Denoising time-domain induced polarisation data using wavelet techniques

NASA Astrophysics Data System (ADS)

Deo, Ravin N.; Cull, James P.

2016-05-01

Time-domain induced polarisation (TDIP) methods are routinely used for near-surface evaluations in quasi-urban environments harbouring networks of buried civil infrastructure. A conventional technique for improving signal to noise ratio in such environments is by using analogue or digital low-pass filtering followed by stacking and rectification. However, this induces large distortions in the processed data. In this study, we have conducted the first application of wavelet based denoising techniques for processing raw TDIP data. Our investigation included laboratory and field measurements to better understand the advantages and limitations of this technique. It was found that distortions arising from conventional filtering can be significantly avoided with the use of wavelet based denoising techniques. With recent advances in full-waveform acquisition and analysis, incorporation of wavelet denoising techniques can further enhance surveying capabilities. In this work, we present the rationale for utilising wavelet denoising methods and discuss some important implications, which can positively influence TDIP methods.

Fungal Diversity in Tomato Rhizosphere Soil under Conventional and Desert Farming Systems

PubMed Central

Kazerooni, Elham A.; Maharachchikumbura, Sajeewa S. N.; Rethinasamy, Velazhahan; Al-Mahrouqi, Hamed; Al-Sadi, Abdullah M.

2017-01-01

This study examined fungal diversity and composition in conventional (CM) and desert farming (DE) systems in Oman. Fungal diversity in the rhizosphere of tomato was assessed using 454-pyrosequencing and culture-based techniques. Both techniques produced variable results in terms of fungal diversity, with 25% of the fungal classes shared between the two techniques. In addition, pyrosequencing recovered more taxa compared to direct plating. These findings could be attributed to the ability of pyrosequencing to recover taxa that cannot grow or are slow growing on culture media. Both techniques showed that fungal diversity in the conventional farm was comparable to that in the desert farm. However, the composition of fungal classes and taxa in the two farming systems were different. Pyrosequencing revealed that Microsporidetes and Dothideomycetes are the two most common fungal classes in CM and DE, respectively. However, the culture-based technique revealed that Eurotiomycetes was the most abundant class in both farming systems and some classes, such as Microsporidetes, were not detected by the culture-based technique. Although some plant pathogens (e.g., Pythium or Fusarium) were detected in the rhizosphere of tomato, the majority of fungal species in the rhizosphere of tomato were saprophytes. Our study shows that the cultivation system may have an impact on fungal diversity. The factors which affected fungal diversity in both farms are discussed. PMID:28824590

[Digital radiography in young children. Considerations based on experiences in practice].

PubMed

Berkhout, W E R; Mileman, P A; Weerheijm, K L

2004-10-01

In dentistry, digital radiology techniques, such as a charge-coupled device and a storage phosphor plate, are gaining popularity. It was the objective of this study to assess the importance of the advantages and disadvantages of digital radiology techniques for bitewing radiography in young children, when compared to conventional film. A group of dentists received a questionnaire regarding their experiences with digital radiology techniques or conventional films among young children. Using the Simple Multi-Attributive Rating Technique (SMART) a final weighted score was calculated for the charge-coupled device, the phosphor plate, and conventional film. The scores were 7.40, 7.38, and 6.98 respectively. The differences were not statistically significant (p > 0.47). It could be concluded that, on the basis of experiences in practice, there are no statistically significant preferences for the use of digital radioogy techniques for bitewing radiography in young children.

The development of additive manufacturing technique for nickel-base alloys: A review

NASA Astrophysics Data System (ADS)

Zadi-Maad, Ahmad; Basuki, Arif

2018-04-01

Nickel-base alloys are an attractive alloy due to its excellent mechanical properties, a high resistance to creep deformation, corrosion, and oxidation. However, it is a hard task to control performance when casting or forging for this material. In recent years, additive manufacturing (AM) process has been implemented to replace the conventional directional solidification process for the production of nickel-base alloys. Due to its potentially lower cost and flexibility manufacturing process, AM is considered as a substitute technique for the existing. This paper provides a comprehensive review of the previous work related to the AM techniques for Ni-base alloys while highlighting current challenges and methods to solving them. The properties of conventionally manufactured Ni-base alloys are also compared with the AM fabricated alloys. The mechanical properties obtained from tension, hardness and fatigue test are included, along with discussions of the effect of post-treatment process. Recommendations for further work are also provided.

Design and Evaluation of Perceptual-based Object Group Selection Techniques

NASA Astrophysics Data System (ADS)

Dehmeshki, Hoda

Selecting groups of objects is a frequent task in graphical user interfaces. It is required prior to many standard operations such as deletion, movement, or modification. Conventional selection techniques are lasso, rectangle selection, and the selection and de-selection of items through the use of modifier keys. These techniques may become time-consuming and error-prone when target objects are densely distributed or when the distances between target objects are large. Perceptual-based selection techniques can considerably improve selection tasks when targets have a perceptual structure, for example when arranged along a line. Current methods to detect such groups use ad hoc grouping algorithms that are not based on results from perception science. Moreover, these techniques do not allow selecting groups with arbitrary arrangements or permit modifying a selection. This dissertation presents two domain-independent perceptual-based systems that address these issues. Based on established group detection models from perception research, the proposed systems detect perceptual groups formed by the Gestalt principles of good continuation and proximity. The new systems provide gesture-based or click-based interaction techniques for selecting groups with curvilinear or arbitrary structures as well as clusters. Moreover, the gesture-based system is adapted for the graph domain to facilitate path selection. This dissertation includes several user studies that show the proposed systems outperform conventional selection techniques when targets form salient perceptual groups and are still competitive when targets are semi-structured.

In silico comparison of the reproducibility of full-arch implant provisional restorations to final restoration between a 3D Scan/CAD/CAM technique and the conventional method.

PubMed

Mino, Takuya; Maekawa, Kenji; Ueda, Akihiro; Higuchi, Shizuo; Sejima, Junichi; Takeuchi, Tetsuo; Hara, Emilio Satoshi; Kimura-Ono, Aya; Sonoyama, Wataru; Kuboki, Takuo

2015-04-01

The aim of this article was to investigate the accuracy in the reproducibility of full-arch implant provisional restorations to final restorations between a 3D Scan/CAD/CAM technique and the conventional method. We fabricated two final restorations for rehabilitation of maxillary and mandibular complete edentulous area and performed a computer-based comparative analysis of the accuracy in the reproducibility of the provisional restoration to final restoration between a 3D scanning and CAD/CAM (Scan/CAD/CAM) technique and the conventional silicone-mold transfer technique. Final restorations fabricated either by the conventional or Scan/CAD/CAM method were successfully installed in the patient. The total concave/convex volume discrepancy observed with the Scan/CAD/CAM technique was 503.50mm(3) and 338.15 mm(3) for maxillary and mandibular implant-supported prostheses (ISPs), respectively. On the other hand, total concave/convex volume discrepancy observed with the conventional method was markedly high (1106.84 mm(3) and 771.23 mm(3) for maxillary and mandibular ISPs, respectively). The results of the present report suggest that Scan/CAD/CAM method enables a more precise and accurate transfer of provisional restorations to final restorations compared to the conventional method. Copyright © 2014 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Computer-Assisted Total Knee Arthroplasty: Is There a Difference Between Image-Based and Imageless Techniques?

PubMed

Tabatabaee, Reza M; Rasouli, Mohammad R; Maltenfort, Mitchell G; Fuino, Robert; Restrepo, Camilo; Oliashirazi, Ali

2018-04-01

Image-based and imageless computer-assisted total knee arthroplasty (CATKA) has become increasingly popular. This study aims to compare outcomes, including perioperative complications and transfusion rate, between CATKA and conventional total knee arthroplasty (TKA), as well as between image-based and imageless CATKA. Using the 9th revision of the International Classification of Diseases codes, we queried the Nationwide Inpatient Sample database from 2005 to 2011 to identify unilateral conventional TKA, image-based, and imageless CATKAs as well as in-hospital complications and transfusion rates. A total of 787,809 conventional TKAs and 13,246 CATKAs (1055 image-based and 12,191 imageless) were identified. The rate of CATKA increased 23.13% per year from 2005 to 2011. Transfusion rates in conventional TKA and CATKA cases were 11.73% and 8.20% respectively (P < .001) and 6.92% in image-based vs 8.27% in imageless (P = .023). Perioperative complications occurred in 4.50%, 3.47%, and 3.41% of cases after conventional, imageless, and imaged-based CATKAs, respectively. Using multivariate analysis, perioperative complications were significantly higher in conventional TKA compared to CATKA (odds ratio = 1.17, 95% confidence interval 1.03-1.33, P = .01). There was no significant difference between imageless and image-based CATKA (P = .34). Length of hospital stay and hospital charges were not significantly different between groups (P > .05). CATKA has low complication rates and may improve patient outcomes after TKA. CATKA, especially the image-based technique, may reduce in-hospital complications and transfusion without increasing hospital charges and length of hospital stay significantly. Large prospective studies with long follow-up are required to verify potential benefits of CATKA. Copyright © 2017 Elsevier Inc. All rights reserved.

Nanoparticle chemisorption printing technique for conductive silver patterning with submicron resolution

PubMed Central

Yamada, Toshikazu; Fukuhara, Katsuo; Matsuoka, Ken; Minemawari, Hiromi; Tsutsumi, Jun'ya; Fukuda, Nobuko; Aoshima, Keisuke; Arai, Shunto; Makita, Yuichi; Kubo, Hitoshi; Enomoto, Takao; Togashi, Takanari; Kurihara, Masato; Hasegawa, Tatsuo

2016-01-01

Silver nanocolloid, a dense suspension of ligand-encapsulated silver nanoparticles, is an important material for printing-based device production technologies. However, printed conductive patterns of sufficiently high quality and resolution for industrial products have not yet been achieved, as the use of conventional printing techniques is severely limiting. Here we report a printing technique to manufacture ultrafine conductive patterns utilizing the exclusive chemisorption phenomenon of weakly encapsulated silver nanoparticles on a photoactivated surface. The process includes masked irradiation of vacuum ultraviolet light on an amorphous perfluorinated polymer layer to photoactivate the surface with pendant carboxylate groups, and subsequent coating of alkylamine-encapsulated silver nanocolloids, which causes amine–carboxylate conversion to trigger the spontaneous formation of a self-fused solid silver layer. The technique can produce silver patterns of submicron fineness adhered strongly to substrates, thus enabling manufacture of flexible transparent conductive sheets. This printing technique could replace conventional vacuum- and photolithography-based device processing. PMID:27091238

Secure positioning technique based on the encrypted visible light map

NASA Astrophysics Data System (ADS)

Lee, Y. U.; Jung, G.

2017-01-01

For overcoming the performance degradation problems of the conventional visible light (VL) positioning system, which are due to the co-channel interference by adjacent light and the irregularity of the VL reception position in the three dimensional (3-D) VL channel, the secure positioning technique based on the two dimensional (2-D) encrypted VL map is proposed, implemented as the prototype for the specific embedded positioning system, and verified by performance tests in this paper. It is shown from the test results that the proposed technique achieves the performance enhancement over 21.7% value better than the conventional one in the real positioning environment, and the well known PN code is the optimal stream encryption key for the good VL positioning.

An automated cross-correlation based event detection technique and its application to surface passive data set

USGS Publications Warehouse

Forghani-Arani, Farnoush; Behura, Jyoti; Haines, Seth S.; Batzle, Mike

2013-01-01

In studies on heavy oil, shale reservoirs, tight gas and enhanced geothermal systems, the use of surface passive seismic data to monitor induced microseismicity due to the fluid flow in the subsurface is becoming more common. However, in most studies passive seismic records contain days and months of data and manually analysing the data can be expensive and inaccurate. Moreover, in the presence of noise, detecting the arrival of weak microseismic events becomes challenging. Hence, the use of an automated, accurate and computationally fast technique for event detection in passive seismic data is essential. The conventional automatic event identification algorithm computes a running-window energy ratio of the short-term average to the long-term average of the passive seismic data for each trace. We show that for the common case of a low signal-to-noise ratio in surface passive records, the conventional method is not sufficiently effective at event identification. Here, we extend the conventional algorithm by introducing a technique that is based on the cross-correlation of the energy ratios computed by the conventional method. With our technique we can measure the similarities amongst the computed energy ratios at different traces. Our approach is successful at improving the detectability of events with a low signal-to-noise ratio that are not detectable with the conventional algorithm. Also, our algorithm has the advantage to identify if an event is common to all stations (a regional event) or to a limited number of stations (a local event). We provide examples of applying our technique to synthetic data and a field surface passive data set recorded at a geothermal site.

Contrast-enhanced spectral mammography based on a photon-counting detector: quantitative accuracy and radiation dose

NASA Astrophysics Data System (ADS)

Lee, Seungwan; Kang, Sooncheol; Eom, Jisoo

2017-03-01

Contrast-enhanced mammography has been used to demonstrate functional information about a breast tumor by injecting contrast agents. However, a conventional technique with a single exposure degrades the efficiency of tumor detection due to structure overlapping. Dual-energy techniques with energy-integrating detectors (EIDs) also cause an increase of radiation dose and an inaccuracy of material decomposition due to the limitations of EIDs. On the other hands, spectral mammography with photon-counting detectors (PCDs) is able to resolve the issues induced by the conventional technique and EIDs using their energy-discrimination capabilities. In this study, the contrast-enhanced spectral mammography based on a PCD was implemented by using a polychromatic dual-energy model, and the proposed technique was compared with the dual-energy technique with an EID in terms of quantitative accuracy and radiation dose. The results showed that the proposed technique improved the quantitative accuracy as well as reduced radiation dose comparing to the dual-energy technique with an EID. The quantitative accuracy of the contrast-enhanced spectral mammography based on a PCD was slightly improved as a function of radiation dose. Therefore, the contrast-enhanced spectral mammography based on a PCD is able to provide useful information for detecting breast tumors and improving diagnostic accuracy.

Analyzing mobile WiMAX base station deployment under different frequency planning strategies

NASA Astrophysics Data System (ADS)

Salman, M. K.; Ahmad, R. B.; Ali, Ziad G.; Aldhaibani, Jaafar A.; Fayadh, Rashid A.

2015-05-01

The frequency spectrum is a precious resource and scarce in the communication markets. Therefore, different techniques are adopted to utilize the available spectrum in deploying WiMAX base stations (BS) in cellular networks. In this paper several types of frequency planning techniques are illustrated, and a comprehensive comparative study between conventional frequency reuse of 1 (FR of 1) and fractional frequency reuse (FFR) is presented. These techniques are widely used in network deployment, because they employ universal frequency (using all the available bandwidth) in their base station installation/configuration within network system. This paper presents a network model of 19 base stations in order to be employed in the comparison of the aforesaid frequency planning techniques. Users are randomly distributed within base stations, users' resource mapping and their burst profile selection are based on the measured signal to interference plus-noise ratio (SINR). Simulation results reveal that the FFR has advantages over the conventional FR of 1 in various metrics. 98 % of downlink resources (slots) are exploited when FFR is applied, whilst it is 81 % at FR of 1. Data rate of FFR has been increased to 10.6 Mbps, while it is 7.98 Mbps at FR of 1. The spectral efficiency is better enhanced (1.072 bps/Hz) at FR of 1 than FFR (0.808 bps/Hz), since FR of 1 exploits all the Bandwidth. The subcarrier efficiency shows how many data bits that can be carried by subcarriers under different frequency planning techniques, the system can carry more data bits under FFR (2.40 bit/subcarrier) than FR of 1 (1.998 bit/subcarrier). This study confirms that FFR can perform better than conventional frequency planning (FR of 1) which made it a strong candidate for WiMAX BS deployment in cellular networks.

Application of advanced techniques for the assessment of bio-stability of biowaste-derived residues: A minireview.

PubMed

Lü, Fan; Shao, Li-Ming; Zhang, Hua; Fu, Wen-Ding; Feng, Shi-Jin; Zhan, Liang-Tong; Chen, Yun-Min; He, Pin-Jing

2018-01-01

Bio-stability is a key feature for the utilization and final disposal of biowaste-derived residues, such as aerobic compost or vermicompost of food waste, bio-dried waste, anaerobic digestate or landfilled waste. The present paper reviews conventional methods and advanced techniques used for the assessment of bio-stability. The conventional methods are reclassified into two categories. Advanced techniques, including spectroscopic (fluorescent, ultraviolet-visible, infrared, Raman, nuclear magnetic resonance), thermogravimetric and thermochemolysis analysis, are emphasized for their application in bio-stability assessment in recent years. Their principles, pros and cons are critically discussed. These advanced techniques are found to be convenient in sample preparation and to supply diversified information. However, the viability of these techniques as potential indicators for bio-stability assessment ultimately lies in the establishment of the relationship of advanced ones with the conventional methods, especially with the methods based on biotic response. Furthermore, some misuses in data explanation should be noted. Copyright © 2017 Elsevier Ltd. All rights reserved.

Detection of swine-origin influenza A (H1N1) viruses using a paired surface plasma waves biosensor

NASA Astrophysics Data System (ADS)

Su, Li-Chen; Chang, Ying-Feng; Li, Ying-Chang; Hsieh, Jo-Ping; Lee, Cheng-Chung; Chou, Chien

2010-08-01

In order to enhance the sensitivity of conventional rapid test technique for the detection of swine-origin influenza A (H1N1) viruses (S-OIVs), we used a paired surface plasma waves biosensor (PSPWB) based on SPR in conjunction with an optical heterodyne technique. Experimentally, PSPWB showed a 125-fold improvement at least in the S-OIV detection as compared to conventional enzyme linked immunosorbent assay. Moreover, the detection limit of the PSPWB for the S-OIV detection was enhanced 250-fold in buffer at least in comparison with that of conventional rapid influenza diagnostic test.

Microbial community composition of the ileum and cecum of broiler chickens as revealed by molecular and culture-based techniques.

PubMed

Bjerrum, L; Engberg, R M; Leser, T D; Jensen, B B; Finster, K; Pedersen, K

2006-07-01

The microbial communities of the ileum and cecum of broiler chickens from a conventional and an organic farm were investigated using conventional culture techniques as well as cloning and sequencing of 16S rRNA genes. Eighty-five percent of the 557 cloned sequences were <97% related to known cultured species. The chicken ileum was dominated by lactobacilli, whereas the cecum harbored a more diverse microbial community. The cecum was dominated by a large group of bacteria with hitherto no close cultured relatives but most closely related to Faecalibacterium prausnitzii. Approximately 49 and 20% of the cecal clones belonged to this cluster in conventional and organic broiler chickens, respectively. We were, however, able to recover a number of these phylotypes by cultivation, and the isolates were shown to be butyric acid producers. The investigation was a descriptive rather than a comparative study of 2 different rearing systems; however, several differences were observed. For instance, Clostridium perfringens was found in significantly higher numbers in the birds from the organic farm compared with the conventional broilers, probably due to the addition of salinomycin to the conventional feed. In the ileum, the abundance of the different Lactobacillus species differed between the 2 broiler types. The culture-based and culture-independent techniques complemented each other well. Strengths and limitations of the different methods are discussed.

Research on ionospheric tomography based on variable pixel height

NASA Astrophysics Data System (ADS)

Zheng, Dunyong; Li, Peiqing; He, Jie; Hu, Wusheng; Li, Chaokui

2016-05-01

A novel ionospheric tomography technique based on variable pixel height was developed for the tomographic reconstruction of the ionospheric electron density distribution. The method considers the height of each pixel as an unknown variable, which is retrieved during the inversion process together with the electron density values. In contrast to conventional computerized ionospheric tomography (CIT), which parameterizes the model with a fixed pixel height, the variable-pixel-height computerized ionospheric tomography (VHCIT) model applies a disturbance to the height of each pixel. In comparison with conventional CIT models, the VHCIT technique achieved superior results in a numerical simulation. A careful validation of the reliability and superiority of VHCIT was performed. According to the results of the statistical analysis of the average root mean square errors, the proposed model offers an improvement by 15% compared with conventional CIT models.

MO-G-BRD-01: Point/Counterpoint Debate: Arc Based Techniques Will Make Conventional IMRT Obsolete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shepard, D; Popple, R; Balter, P

2014-06-15

A variety of intensity modulated radiation therapy (IMRT) delivery techniques have been developed that have provided clinicians with the ability to deliver highly conformal dose distributions. The delivery techniques include compensators, step-and-shoot IMRT, sliding window IMRT, volumetric modulated arc therapy (VMAT), and tomotherapy. A key development in the field of IMRT was the introduction of new planning algorithms and delivery control systems in 2007 that made it possible to coordinate the gantry rotation speed, dose rate, and multileaf collimator leaf positions during the delivery of arc therapy. With these developments, VMAT became a routine clinical tool. The use of VMATmore » has continued to grow in recent years and some would argue that this will soon make conventional IMRT obsolete, and this is the premise of this debate. To introduce the debate, David Shepard, Ph.D. will provide an overview of IMRT delivery techniques including historical context and how they are being used today. The debate will follow with Richard Popple, Ph.D. arguing FOR the Proposition and Peter Balter, Ph.D. arguing AGAINST it. Learning Objectives: Understand the different delivery techniques for IMRT. Understand the potential benefits of conventional IMRT. Understand the potential benefits of arc-based IMRT delivery.« less

Noble-TLBO MPPT Technique and its Comparative Analysis with Conventional methods implemented on Solar Photo Voltaic System

NASA Astrophysics Data System (ADS)

Patsariya, Ajay; Rai, Shiwani; Kumar, Yogendra, Dr.; Kirar, Mukesh, Dr.

2017-08-01

The energy crisis particularly with developing GDPs, has bring up to a new panorama of sustainable power source like solar energy, which has encountered huge development. Progressively high infiltration level of photovoltaic (PV) era emerges in keen matrix. Sunlight based power is irregular and variable, as the sun based source at the ground level is exceedingly subject to overcast cover inconstancy, environmental vaporized levels, and other climate parameters. The inalienable inconstancy of substantial scale sun based era acquaints huge difficulties with keen lattice vitality administration. Exact determining of sun powered power/irradiance is basic to secure financial operation of the shrewd framework. In this paper a noble TLBO-MPPT technique has been proposed to address the vitality of solar energy. A comparative analysis has been presented between conventional PO, IC and the proposed MPPT technique. The research has been done on Matlab Simulink software version 2013.

Robust myoelectric signal detection based on stochastic resonance using multiple-surface-electrode array made of carbon nanotube composite paper

NASA Astrophysics Data System (ADS)

Shirata, Kento; Inden, Yuki; Kasai, Seiya; Oya, Takahide; Hagiwara, Yosuke; Kaeriyama, Shunichi; Nakamura, Hideyuki

2016-04-01

We investigated the robust detection of surface electromyogram (EMG) signals based on the stochastic resonance (SR) phenomenon, in which the response to weak signals is optimized by adding noise, combined with multiple surface electrodes. Flexible carbon nanotube composite paper (CNT-cp) was applied to the surface electrode, which showed good performance that is comparable to that of conventional Ag/AgCl electrodes. The SR-based EMG signal system integrating an 8-Schmitt-trigger network and the multiple-CNT-cp-electrode array successfully detected weak EMG signals even when the subject’s body is in the motion, which was difficult to achieve using the conventional technique. The feasibility of the SR-based EMG detection technique was confirmed by demonstrating its applicability to robot hand control.

SU-F-T-380: Comparing the Effect of Respiration On Dose Distribution Between Conventional Tangent Pair and IMRT Techniques for Adjuvant Radiotherapy in Early Stage Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, M; Ramaseshan, R

2016-06-15

Purpose: In this project, we compared the conventional tangent pair technique to IMRT technique by analyzing the dose distribution. We also investigated the effect of respiration on planning target volume (PTV) dose coverage in both techniques. Methods: In order to implement IMRT technique a template based planning protocol, dose constrains and treatment process was developed. Two open fields with optimized field weights were combined with two beamlet optimization fields in IMRT plans. We compared the dose distribution between standard tangential pair and IMRT. The improvement in dose distribution was measured by parameters such as conformity index, homogeneity index and coveragemore » index. Another end point was the IMRT technique will reduce the planning time for staff. The effect of patient’s respiration on dose distribution was also estimated. The four dimensional computed tomography (4DCT) for different phase of breathing cycle was used to evaluate the effect of respiration on IMRT planned dose distribution. Results: We have accumulated 10 patients that acquired 4DCT and planned by both techniques. Based on the preliminary analysis, the dose distribution in IMRT technique was better than conventional tangent pair technique. Furthermore, the effect of respiration in IMRT plan was not significant as evident from the 95% isodose line coverage of PTV drawn on all phases of 4DCT. Conclusion: Based on the 4DCT images, the breathing effect on dose distribution was smaller than what we expected. We suspect that there are two reasons. First, the PTV movement due to respiration was not significant. It might be because we used a tilted breast board to setup patients. Second, the open fields with optimized field weights in IMRT technique might reduce the breathing effect on dose distribution. A further investigation is necessary.« less

Improved aortic enhancement in CT angiography using slope-based triggering with table speed optimization: a pilot study.

PubMed

Bashir, Mustafa R; Weber, Paul W; Husarik, Daniela B; Howle, Laurens E; Nelson, Rendon C

2012-08-01

To assess whether a scan triggering technique based on the slope of the time-attenuation curve combined with table speed optimization may improve arterial enhancement in aortic CT angiography compared to conventional threshold-based triggering techniques. Measurements of arterial enhancement were performed in a physiologic flow phantom over a range of simulated cardiac outputs (2.2-8.1 L/min) using contrast media boluses of 80 and 150 mL injected at 4 mL/s. These measurements were used to construct computer models of aortic attenuation in CT angiography, using cardiac output, aortic diameter, and CT table speed as input parameters. In-plane enhancement was calculated for normal and aneurysmal aortic diameters. Calculated arterial enhancement was poor (<150 HU) along most of the scan length using the threshold-based triggering technique for low cardiac outputs and the aneurysmal aorta model. Implementation of the slope-based triggering technique with table speed optimization improved enhancement in all scenarios and yielded good- (>200 HU; 13/16 scenarios) to excellent-quality (>300 HU; 3/16 scenarios) enhancement in all cases. Slope-based triggering with table speed optimization may improve the technical quality of aortic CT angiography over conventional threshold-based techniques, and may reduce technical failures related to low cardiac output and slow flow through an aneurysmal aorta.

Dynamic time warping-based averaging framework for functional near-infrared spectroscopy brain imaging studies

NASA Astrophysics Data System (ADS)

Zhu, Li; Najafizadeh, Laleh

2017-06-01

We investigate the problem related to the averaging procedure in functional near-infrared spectroscopy (fNIRS) brain imaging studies. Typically, to reduce noise and to empower the signal strength associated with task-induced activities, recorded signals (e.g., in response to repeated stimuli or from a group of individuals) are averaged through a point-by-point conventional averaging technique. However, due to the existence of variable latencies in recorded activities, the use of the conventional averaging technique can lead to inaccuracies and loss of information in the averaged signal, which may result in inaccurate conclusions about the functionality of the brain. To improve the averaging accuracy in the presence of variable latencies, we present an averaging framework that employs dynamic time warping (DTW) to account for the temporal variation in the alignment of fNIRS signals to be averaged. As a proof of concept, we focus on the problem of localizing task-induced active brain regions. The framework is extensively tested on experimental data (obtained from both block design and event-related design experiments) as well as on simulated data. In all cases, it is shown that the DTW-based averaging technique outperforms the conventional-based averaging technique in estimating the location of task-induced active regions in the brain, suggesting that such advanced averaging methods should be employed in fNIRS brain imaging studies.

Reinforcing the role of the conventional C-arm--a novel method for simplified distal interlocking.

PubMed

Windolf, Markus; Schroeder, Josh; Fliri, Ladina; Dicht, Benno; Liebergall, Meir; Richards, R Geoff

2012-01-25

The common practice for insertion of distal locking screws of intramedullary nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure of the patient and the surgical personnel. A new concept is introduced utilizing information from within conventional radiographic images to help accurately guide the surgeon to place the interlocking bolt into the interlocking hole. The newly developed technique was compared to conventional freehand in an operating room (OR) like setting on human cadaveric lower legs in terms of operating time and radiation exposure. The proposed concept (guided freehand), generally based on the freehand gold standard, additionally guides the surgeon by means of visible landmarks projected into the C-arm image. A computer program plans the correct drilling trajectory by processing the lens-shaped hole projections of the interlocking holes from a single image. Holes can be drilled by visually aligning the drill to the planned trajectory. Besides a conventional C-arm, no additional tracking or navigation equipment is required.Ten fresh frozen human below-knee specimens were instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland). The implants were distally locked by performing the newly proposed technique as well as the conventional freehand technique on each specimen. An orthopedic resident surgeon inserted four distal screws per procedure. Operating time, number of images and radiation time were recorded and statistically compared between interlocking techniques using non-parametric tests. A 58% reduction in number of taken images per screw was found for the guided freehand technique (7.4 ± 3.4) (mean ± SD) compared to the freehand technique (17.6 ± 10.3) (p < 0.001). Total radiation time (all 4 screws) was 55% lower for the guided freehand technique compared to conventional freehand (p = 0.001). Operating time per screw (from first shot to screw tightened) was on average 22% reduced by guided freehand (p = 0.018). In an experimental setting, the newly developed guided freehand technique for distal interlocking has proven to markedly reduce radiation exposure when compared to the conventional freehand technique. The method utilizes established clinical workflows and does not require cost intensive add-on devices or extensive training. The underlying principle carries potential to assist implant positioning in numerous other applications within orthopedics and trauma from screw insertions to placement of plates, nails or prostheses.

Pseudo color ghost coding imaging with pseudo thermal light

NASA Astrophysics Data System (ADS)

Duan, De-yang; Xia, Yun-jie

2018-04-01

We present a new pseudo color imaging scheme named pseudo color ghost coding imaging based on ghost imaging but with multiwavelength source modulated by a spatial light modulator. Compared with conventional pseudo color imaging where there is no nondegenerate wavelength spatial correlations resulting in extra monochromatic images, the degenerate wavelength and nondegenerate wavelength spatial correlations between the idle beam and signal beam can be obtained simultaneously. This scheme can obtain more colorful image with higher quality than that in conventional pseudo color coding techniques. More importantly, a significant advantage of the scheme compared to the conventional pseudo color coding imaging techniques is the image with different colors can be obtained without changing the light source and spatial filter.

Dynamic tables: an architecture for managing evolving, heterogeneous biomedical data in relational database management systems.

PubMed

Corwin, John; Silberschatz, Avi; Miller, Perry L; Marenco, Luis

2007-01-01

Data sparsity and schema evolution issues affecting clinical informatics and bioinformatics communities have led to the adoption of vertical or object-attribute-value-based database schemas to overcome limitations posed when using conventional relational database technology. This paper explores these issues and discusses why biomedical data are difficult to model using conventional relational techniques. The authors propose a solution to these obstacles based on a relational database engine using a sparse, column-store architecture. The authors provide benchmarks comparing the performance of queries and schema-modification operations using three different strategies: (1) the standard conventional relational design; (2) past approaches used by biomedical informatics researchers; and (3) their sparse, column-store architecture. The performance results show that their architecture is a promising technique for storing and processing many types of data that are not handled well by the other two semantic data models.

Timing Recovery Strategies in Magnetic Recording Systems

NASA Astrophysics Data System (ADS)

Kovintavewat, Piya

At some point in a digital communications receiver, the received analog signal must be sampled. Good performance requires that these samples be taken at the right times. The process of synchronizing the sampler with the received analog waveform is known as timing recovery. Conventional timing recovery techniques perform well only when operating at high signal-to-noise ratio (SNR). Nonetheless, iterative error-control codes allow reliable communication at very low SNR, where conventional techniques fail. This paper provides a detailed review on the timing recovery strategies based on per-survivor processing (PSP) that are capable of working at low SNR. We also investigate their performance in magnetic recording systems because magnetic recording is a primary method of storage for a variety of applications, including desktop, mobile, and server systems. Results indicate that the timing recovery strategies based on PSP perform better than the conventional ones and are thus worth being employed in magnetic recording systems.

Fast algorithm for the rendering of three-dimensional surfaces

NASA Astrophysics Data System (ADS)

Pritt, Mark D.

1994-02-01

It is often desirable to draw a detailed and realistic representation of surface data on a computer graphics display. One such representation is a 3D shaded surface. Conventional techniques for rendering shaded surfaces are slow, however, and require substantial computational power. Furthermore, many techniques suffer from aliasing effects, which appear as jagged lines and edges. This paper describes an algorithm for the fast rendering of shaded surfaces without aliasing effects. It is much faster than conventional ray tracing and polygon-based rendering techniques and is suitable for interactive use. On an IBM RISC System/6000TM workstation it renders a 1000 X 1000 surface in about 7 seconds.

Broadband linearisation of high-efficiency power amplifiers

NASA Technical Reports Server (NTRS)

Kenington, Peter B.; Parsons, Kieran J.; Bennett, David W.

1993-01-01

A feedforward-based amplifier linearization technique is presented which is capable of yielding significant improvements in both linearity and power efficiency over conventional amplifier classes (e.g. class-A or class-AB). Theoretical and practical results are presented showing that class-C stages may be used for both the main and error amplifiers yielding practical efficiencies well in excess of 30 percent, with theoretical efficiencies of much greater than 40 percent being possible. The levels of linearity which may be achieved are required for most satellite systems, however if greater linearity is required, the technique may be used in addition to conventional pre-distortion techniques.

Fast measurement of bacterial susceptibility to antibiotics

NASA Technical Reports Server (NTRS)

Chappelle, E. W.; Picciolo, G. L.; Schrock, C. G.

1977-01-01

Method, based on photoanalysis of adenosine triphosphate using light-emitting reaction with luciferase-luciferin technique, saves time by eliminating isolation period required by conventional methods. Technique is also used to determine presence of infection as well as susceptibilities to several antibiotics.

Harnessing Solid-State Ionic Transport for Nanomanufacturing and Nanodevices

ERIC Educational Resources Information Center

Hsu, Keng Hao

2009-01-01

Through this work a new all-solid, ambient processing condition direct metal patterning technique has been developed and characterized. This ionic-transport-based patterning technique is capable of sub-50nm feature resolution under ambient conditions. It generates features with a rate that is comparable to conventional dry-etching techniques. A…

OCT evaluation of single ceramic crowns: comparison between conventional and chair-side CAD/CAM technologies

NASA Astrophysics Data System (ADS)

Gabor, A.; Jivanescu, A.; Zaharia, C.; Hategan, S.; Topala, F. I.; Levai, C. M.; Negrutiu, M. L.; Sinescu, C.; Duma, V.-F.; Bradu, A.; Podoleanu, A. Gh.

2016-03-01

Digital impressions were introduced to overcome some of the obstacles due to traditional impression materials and techniques. The aim of this in vitro study is to compare the accuracy of all ceramic crowns obtained with digital impression and CAD-CAM technology with the accuracy of those obtained with conventional impression techniques. Two groups of 10 crowns each have been considered. The digital data obtained from Group 1 have been processed and the all-ceramic crowns were milled with a CAD/CAM technology (CEREC MCX, Sirona). The all ceramic crowns in Group 2 were obtained with the classical technique of pressing (emax, Ivoclar, Vivadent). The evaluation of the marginal adaptation was performed with Time Domain Optical Coherence Tomography (TD OCT), working at a wavelength of 1300 nm. Tri-dimensional (3D) reconstructions of the selected areas were obtained. Based on the findings in this study, one may conclude that the marginal accuracy of all ceramic crowns fabricated with digital impression and the CAD/CAM technique is superior to the conventional impression technique.

[Strategies to identify supernumerary chromosomal markers in constitutional cytogenetics].

PubMed

Douet-Guilbert, N; Basinko, A; Le Bris, M-J; Herry, A; Morel, F; De Braekeleer, M

2008-09-01

Supernumerary marker chromosomes (SMCs) are defined as extrastructurally abnormal chromosomes which origin and composition cannot be determined by conventional cytogenetics. SMCs are an heterogeneous group of abnormalities concerning all chromosomes with variable structure and size and are associated with phenotypic heterogeneity. The characterisation of SMCs is of utmost importance for genetic counselling. Different molecular techniques are used to identify chromosomal material present in markers such as 24-colour FISH (MFISH, SKY), centromere specific multicolour FISH (cenMFISH) and derivatives (acroMFISH, subcenMFISH), comparative genomic hybridisation (CGH), arrayCGH, and targeted FISH techniques (banding techniques, whole chromosome painting...). Based on the morphology of SMC with conventional cytogenetic and clinical data, we tried to set up different molecular strategies with all available techniques.

Ionic liquid-based ultrasonic/microwave-assisted extraction combined with UPLC-MS-MS for the determination of tannins in Galla chinensis.

PubMed

Lu, Chunxia; Wang, Hongxin; Lv, Wenping; Ma, Chaoyang; Lou, Zaixiang; Xie, Jun; Liu, Bo

2012-01-01

Ionic liquid was used as extraction solvents and applied to the extraction of tannins from Galla chinensis in the simultaneous ultrasonic- and microwave-assisted extraction (UMAE) technique. Several parameters of UMAE were optimised, and the results were compared with of the conventional extraction techniques. Under optimal conditions, the content of tannins was 630.2 ± 12.1 mg g⁻¹. Compared with the conventional heat-reflux extraction, maceration extraction, regular ultrasound- and microwave-assisted extraction, the proposed approach exhibited higher efficiency (11.7-22.0% enhanced) and shorter extraction time (from 6 h to 1 min). The tannins were then identified by ultraperformance liquid chromatography tandem mass spectrometry. This study suggests that ionic liquid-based UMAE is an efficient, rapid, simple and green sample preparation technique.

Comparison of denture base adaptation between CAD-CAM and conventional fabrication techniques.

PubMed

Goodacre, Brian J; Goodacre, Charles J; Baba, Nadim Z; Kattadiyil, Mathew T

2016-08-01

Currently no data comparing the denture base adaptation of CAD-CAM and conventional denture processing techniques have been reported. The purpose of this in vitro study was to compare the denture base adaptation of pack and press, pour, injection, and CAD-CAM techniques for fabricating dentures to determine which process produces the most accurate and reproducible adaptation. A definitive cast was duplicated to create 40 gypsum casts that were laser scanned before any fabrication procedures were initiated. A master denture was made using the CAD-CAM process and was then used to create a putty mold for the fabrication of 30 standardized wax festooned dentures, 10 for each of the conventional processing techniques (pack and press, pour, injection). Scan files from 10 casts were sent to Global Dental Science, LLC for fabrication of the CAD-CAM test specimens. After specimens for each of the 4 techniques had been fabricated, they were hydrated for 24 hours and the intaglio surface laser scanned. The scan file of each denture was superimposed on the scan file of the corresponding preprocessing cast using surface matching software. Measurements were made at 60 locations, providing evaluation of fit discrepancies at the following areas: apex of the denture border, 6 mm from the denture border, crest of the ridge, palate, and posterior palatal seal. The use of median and interquartile range was used to assess accuracy and reproducibility. The Levine and Kruskal-Wallis analysis of variance was used to evaluate differences between processing techniques at the 5 specified locations (α=.05). The ranking of results based on median and interquartile range determined that the accuracy and reproducibility of the CAD-CAM technique was more consistently localized around zero at 3 of the 5 locations. Therefore, the CAD-CAM technique showed the best combination of accuracy and reproducibility among the tested fabrication techniques. The pack and press technique was more accurate at 2 of the 5 locations; however, its interquartile range (reproducibility) was the greatest of the 4 tested processing techniques. The pour technique was the most reproducible at 2 of the 5 locations; however, its accuracy was the lowest of the tested techniques. The CAD-CAM fabrication process was the most accurate and reproducible denture fabrication technique when compared with pack and press, pour, and injection denture base processing techniques. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Systematic methods for the design of a class of fuzzy logic controllers

NASA Astrophysics Data System (ADS)

Yasin, Saad Yaser

2002-09-01

Fuzzy logic control, a relatively new branch of control, can be used effectively whenever conventional control techniques become inapplicable or impractical. Various attempts have been made to create a generalized fuzzy control system and to formulate an analytically based fuzzy control law. In this study, two methods, the left and right parameterization method and the normalized spline-base membership function method, were utilized for formulating analytical fuzzy control laws in important practical control applications. The first model was used to design an idle speed controller, while the second was used to control an inverted control problem. The results of both showed that a fuzzy logic control system based on the developed models could be used effectively to control highly nonlinear and complex systems. This study also investigated the application of fuzzy control in areas not fully utilizing fuzzy logic control. Three important practical applications pertaining to the automotive industries were studied. The first automotive-related application was the idle speed of spark ignition engines, using two fuzzy control methods: (1) left and right parameterization, and (2) fuzzy clustering techniques and experimental data. The simulation and experimental results showed that a conventional controller-like performance fuzzy controller could be designed based only on experimental data and intuitive knowledge of the system. In the second application, the automotive cruise control problem, a fuzzy control model was developed using parameters adaptive Proportional plus Integral plus Derivative (PID)-type fuzzy logic controller. Results were comparable to those using linearized conventional PID and linear quadratic regulator (LQR) controllers and, in certain cases and conditions, the developed controller outperformed the conventional PID and LQR controllers. The third application involved the air/fuel ratio control problem, using fuzzy clustering techniques, experimental data, and a conversion algorithm, to develop a fuzzy-based control algorithm. Results were similar to those obtained by recently published conventional control based studies. The influence of the fuzzy inference operators and parameters on performance and stability of the fuzzy logic controller was studied Results indicated that, the selections of certain parameters or combinations of parameters, affect greatly the performance and stability of the fuzzy controller. Diagnostic guidelines used to tune or change certain factors or parameters to improve controller performance were developed based on knowledge gained from conventional control methods and knowledge gained from the experimental and the simulation results of this study.

A Sparsity-based Framework for Resolution Enhancement in Optical Fault Analysis of Integrated Circuits

DTIC Science & Technology

2015-01-01

for IC fault detection . This section provides background information on inversion methods. Conventional inversion techniques and their shortcomings are...physical techniques, electron beam imaging/analysis, ion beam techniques, scanning probe techniques. Electrical tests are used to detect faults in 13 an...hand, there is also the second harmonic technique through which duty cycle degradation faults are detected by collecting the magnitude and the phase of

ThinPrep versus conventional smear cytologic preparations in the analysis of thyroid fine-needle aspiration specimens.

PubMed

Biscotti, C V; Hollow, J A; Toddy, S M; Easley, K A

1995-08-01

Paired fine-needle aspiration specimens were analyzed from 41 surgically resected thyroid nodules, to compare diagnostic accuracy, amount (absent, mild, moderate, or marked) and pattern (diffuse, droplets, or both) of colloid, nuclear detail (poor, satisfactory, or excellent) and cytoplasmic detail (intact or disrupted) in ThinPrep (TP) (Cytyc, Marlborough, MA) versus conventional smear (CS) cytologic preparations. The 41 surgical specimens included 25 colloid nodules, 6 papillary carcinomas, 4 follicular adenomas, 2 minimally invasive (encapsulated) follicular carcinomas, 3 Hashimoto's thyroiditis, and 1 Grave's disease. Both techniques identified seven of the eight carcinomas with the minimally invasive follicular carcinomas categorized as hypercellular follicular nodule, possibly malignant (HCFN). One papillary carcinoma was classified as a HCFN by both TP and CS techniques. The four follicular adenomas were classified as HCFN based on the TP slides. One oxyphilic follicular adenoma, associated with focal lymphocytic thyroiditis, was misinterpreted as Hashimoto's thyroiditis on a conventional smear. Three colloid nodules were interpreted as HCFN based on the TP slides. Two of these were similarly classified based on the conventional smear. ThinPrep slides contained less colloid and the colloid occurred as droplets rather than a diffuse pattern. TP slides had better nuclear detail but more often disrupted cytoplasm. In conclusion, the TP process does alter some cellular features; however, we experienced similar diagnostic accuracy with the TP and conventional smear preparations.

Comparison of marginal accuracy of castings fabricated by conventional casting technique and accelerated casting technique: an in vitro study.

PubMed

Reddy, S Srikanth; Revathi, Kakkirala; Reddy, S Kranthikumar

2013-01-01

Conventional casting technique is time consuming when compared to accelerated casting technique. In this study, marginal accuracy of castings fabricated using accelerated and conventional casting technique was compared. 20 wax patterns were fabricated and the marginal discrepancy between the die and patterns were measured using Optical stereomicroscope. Ten wax patterns were used for Conventional casting and the rest for Accelerated casting. A Nickel-Chromium alloy was used for the casting. The castings were measured for marginal discrepancies and compared. Castings fabricated using Conventional casting technique showed less vertical marginal discrepancy than the castings fabricated by Accelerated casting technique. The values were statistically highly significant. Conventional casting technique produced better marginal accuracy when compared to Accelerated casting. The vertical marginal discrepancy produced by the Accelerated casting technique was well within the maximum clinical tolerance limits. Accelerated casting technique can be used to save lab time to fabricate clinical crowns with acceptable vertical marginal discrepancy.

Objective response detection in an electroencephalogram during somatosensory stimulation.

PubMed

Simpson, D M; Tierra-Criollo, C J; Leite, R T; Zayen, E J; Infantosi, A F

2000-06-01

Techniques for objective response detection aim to identify the presence of evoked potentials based purely on statistical principles. They have been shown to be potentially more sensitive than the conventional approach of subjective evaluation by experienced clinicians and could be of great clinical use. Three such techniques to detect changes in an electroencephalogram (EEG) synchronous with the stimuli, namely, magnitude-squared coherence (MSC), the phase-synchrony measure (PSM) and the spectral F test (SFT) were applied to EEG signals of 12 normal subjects under conventional somatosensory pulse stimulation to the tibial nerve. The SFT, which uses only the power spectrum, showed the poorest performance, while the PSM, based only on the phase spectrum, gave results almost as good as those of the MSC, which uses both phase and power spectra. With the latter two techniques, stimulus responses were evident in the frequency range of 20-80 Hz in all subjects after 200 stimuli (5 Hz stimulus frequency), whereas for visual recognition at least 500 stimuli are usually applied. Based on these results and on simulations, the phase-based techniques appear promising for the automated detection and monitoring of somatosensory evoked potentials.

Construction of dynamic stochastic simulation models using knowledge-based techniques

NASA Technical Reports Server (NTRS)

Williams, M. Douglas; Shiva, Sajjan G.

1990-01-01

Over the past three decades, computer-based simulation models have proven themselves to be cost-effective alternatives to the more structured deterministic methods of systems analysis. During this time, many techniques, tools and languages for constructing computer-based simulation models have been developed. More recently, advances in knowledge-based system technology have led many researchers to note the similarities between knowledge-based programming and simulation technologies and to investigate the potential application of knowledge-based programming techniques to simulation modeling. The integration of conventional simulation techniques with knowledge-based programming techniques is discussed to provide a development environment for constructing knowledge-based simulation models. A comparison of the techniques used in the construction of dynamic stochastic simulation models and those used in the construction of knowledge-based systems provides the requirements for the environment. This leads to the design and implementation of a knowledge-based simulation development environment. These techniques were used in the construction of several knowledge-based simulation models including the Advanced Launch System Model (ALSYM).

Independent component analysis based digital signal processing in coherent optical fiber communication systems

NASA Astrophysics Data System (ADS)

Li, Xiang; Luo, Ming; Qiu, Ying; Alphones, Arokiaswami; Zhong, Wen-De; Yu, Changyuan; Yang, Qi

2018-02-01

In this paper, channel equalization techniques for coherent optical fiber transmission systems based on independent component analysis (ICA) are reviewed. The principle of ICA for blind source separation is introduced. The ICA based channel equalization after both single-mode fiber and few-mode fiber transmission for single-carrier and orthogonal frequency division multiplexing (OFDM) modulation formats are investigated, respectively. The performance comparisons with conventional channel equalization techniques are discussed.

Development of a New Diagnostic System for Human Liver Diseases Based on Conventional Ultrasonic Diagnostic Equipment

NASA Astrophysics Data System (ADS)

Kikuchi, Tsuneo; Nakazawa, Toshihiro; Harada, Akimitsu; Sato, Hiroaki; Maruyama, Yukio; Sato, Sojun

2001-05-01

In this paper, the authors present the experimental results of using a quantitative ultrasonic diagnosis technique for human liver diseases using the fractal dimension (FD) of the shape of the power spectra (PS) of RF signals. We have developed an experimental system based on a conventional ultrasonic diagnostic system. As a result, we show that normal livers, fatty livers and liver cirrhosis can be identified using the FD values.

Post-processing techniques to enhance reliability of assignment algorithm based performance measures : [technical summary].

DOT National Transportation Integrated Search

2011-01-01

Travel demand modeling plays a key role in the transportation system planning and evaluation process. The four-step sequential travel demand model is the most widely used technique in practice. Traffic assignment is the key step in the conventional f...

Reinforcing the role of the conventional C-arm - a novel method for simplified distal interlocking

PubMed Central

2012-01-01

Background The common practice for insertion of distal locking screws of intramedullary nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure of the patient and the surgical personnel. A new concept is introduced utilizing information from within conventional radiographic images to help accurately guide the surgeon to place the interlocking bolt into the interlocking hole. The newly developed technique was compared to conventional freehand in an operating room (OR) like setting on human cadaveric lower legs in terms of operating time and radiation exposure. Methods The proposed concept (guided freehand), generally based on the freehand gold standard, additionally guides the surgeon by means of visible landmarks projected into the C-arm image. A computer program plans the correct drilling trajectory by processing the lens-shaped hole projections of the interlocking holes from a single image. Holes can be drilled by visually aligning the drill to the planned trajectory. Besides a conventional C-arm, no additional tracking or navigation equipment is required. Ten fresh frozen human below-knee specimens were instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland). The implants were distally locked by performing the newly proposed technique as well as the conventional freehand technique on each specimen. An orthopedic resident surgeon inserted four distal screws per procedure. Operating time, number of images and radiation time were recorded and statistically compared between interlocking techniques using non-parametric tests. Results A 58% reduction in number of taken images per screw was found for the guided freehand technique (7.4 ± 3.4) (mean ± SD) compared to the freehand technique (17.6 ± 10.3) (p < 0.001). Total radiation time (all 4 screws) was 55% lower for the guided freehand technique compared to conventional freehand (p = 0.001). Operating time per screw (from first shot to screw tightened) was on average 22% reduced by guided freehand (p = 0.018). Conclusions In an experimental setting, the newly developed guided freehand technique for distal interlocking has proven to markedly reduce radiation exposure when compared to the conventional freehand technique. The method utilizes established clinical workflows and does not require cost intensive add-on devices or extensive training. The underlying principle carries potential to assist implant positioning in numerous other applications within orthopedics and trauma from screw insertions to placement of plates, nails or prostheses. PMID:22276698

New surgical approach for root coverage of localized gingival recession with acellular dermal matrix: a 12-month comparative clinical study.

PubMed

Barros, Raquel R M; Novaes, Arthur B; Grisi, Márcio F M; Souza, Sérgio L S; Taba, Mário; Palioto, Daniela B

2005-01-01

Acellular dermal matrix graft (ADMG) has been used as an advantageous substitute for autogenous subepithelial connective tissue graft (SCTG). However, the surgical techniques used were primarily developed for the SCTG, and they may not be adequate for ADMG since it has a different healing process than SCTG owing to its different vascular and cellular structures. This study compared the 1-year clinical outcome of a new surgical approach with the outcome of a conventional procedure for the treatment of localized gingival recessions, both performed using the ADMG. The clinical parameters-probing depth, relative clinical attachment level, gingival recession (GR), and width of keratinized tissue-of 32 bilateral Miller Class I or II gingival recessions were assessed at baseline and 12 months postoperatively. Significant clinical changes for both surgical techniques were achieved after this period, including GR reduction from 3.4 mm presurgery to 1.2 mm at 1 year for the conventional technique and from 3.9 mm presurgery to 0.7 mm at 1 year for the new technique. The percentage of root coverage was 62.3% and 82.5% for the conventional and new techniques, respectively. Comparisons between the groups after this period by Mann-Whitney rank sum test revealed statistically significant greater reduction of GR favoring the new procedure (p = .000). Based on the results of this study, it can be concluded that a new surgical technique using an ADMG is more suitable for root coverage when compared with the conventional technique. The results revealed a statistically significant improvement in clinical performance with the ADMG approach.

Wave Propagation Through Inhomogeneities With Applications to Novel Sensing Techniques

NASA Technical Reports Server (NTRS)

Adamovsky, G.; Tokars, R.; Varga, D.; Floyd B.

2008-01-01

The paper describes phenomena observed as a result of laser pencil beam interactions with abrupt interfaces including aerodynamic shocks. Based on these phenomena, a novel flow visualization technique based on a laser scanning pencil beam is introduced. The technique reveals properties of light interaction with interfaces including aerodynamic shocks that are not seen using conventional visualization. Various configurations of scanning beam devices including those with no moving parts, as well as results of "proof-of-concept" tests, are included.

Energy-efficient writing scheme for magnetic domain-wall motion memory

NASA Astrophysics Data System (ADS)

Kim, Kab-Jin; Yoshimura, Yoko; Ham, Woo Seung; Ernst, Rick; Hirata, Yuushou; Li, Tian; Kim, Sanghoon; Moriyama, Takahiro; Nakatani, Yoshinobu; Ono, Teruo

2017-04-01

We present an energy-efficient magnetic domain-writing scheme for domain wall (DW) motion-based memory devices. A cross-shaped nanowire is employed to inject a domain into the nanowire through current-induced DW propagation. The energy required for injecting the magnetic domain is more than one order of magnitude lower than that for the conventional field-based writing scheme. The proposed scheme is beneficial for device miniaturization because the threshold current for DW propagation scales with the device size, which cannot be achieved in the conventional field-based technique.

High-speed machining of Space Shuttle External Tank (ET) panels

NASA Technical Reports Server (NTRS)

Miller, J. A.

1983-01-01

Potential production rates and project cost savings achieved by converting the conventional machining process in manufacturing shuttle external tank panels to high speed machining (HSM) techniques were studied. Savings were projected from the comparison of current production rates with HSM rates and with rates attainable on new conventional machines. The HSM estimates were also based on rates attainable by retrofitting existing conventional equipment with high speed spindle motors and rates attainable using new state of the art machines designed and built for HSM.

Tailor-made Surgical Guide Reduces Incidence of Outliers of Cup Placement.

PubMed

Hananouchi, Takehito; Saito, Masanobu; Koyama, Tsuyoshi; Sugano, Nobuhiko; Yoshikawa, Hideki

2010-04-01

Malalignment of the cup in total hip arthroplasty (THA) increases the risks of postoperative complications such as neck cup impingement, dislocation, and wear. We asked whether a tailor-made surgical guide based on CT images would reduce the incidence of outliers beyond 10 degrees from preoperatively planned alignment of the cup compared with those without the surgical guide. We prospectively followed 38 patients (38 hips, Group 1) having primary THA with the conventional technique and 31 patients (31 hips, Group 2) using the surgical guide. We designed the guide for Group 2 based on CT images and fixed it to the acetabular edge with a Kirschner wire to indicate the planned cup direction. Postoperative CT images showed the guide reduced the number of outliers compared with the conventional method (Group 1, 23.7%; Group 2, 0%). The surgical guide provided more reliable cup insertion compared with conventional techniques. Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

High-speed engine/component performance assessment using exergy and thrust-based methods

NASA Technical Reports Server (NTRS)

Riggins, D. W.

1996-01-01

This investigation summarizes a comparative study of two high-speed engine performance assessment techniques based on energy (available work) and thrust-potential (thrust availability). Simple flow-fields utilizing Rayleigh heat addition and one-dimensional flow with friction are used to demonstrate the fundamental inability of conventional energy techniques to predict engine component performance, aid in component design, or accurately assess flow losses. The use of the thrust-based method on these same examples demonstrates its ability to yield useful information in all these categories. Energy and thrust are related and discussed from the stand-point of their fundamental thermodynamic and fluid dynamic definitions in order to explain the differences in information obtained using the two methods. The conventional definition of energy is shown to include work which is inherently unavailable to an aerospace Brayton engine. An engine-based energy is then developed which accurately accounts for this inherently unavailable work; performance parameters based on this quantity are then shown to yield design and loss information equivalent to the thrust-based method.

Bone Healing Around Dental Implants: Simplified vs Conventional Drilling Protocols at Speed of 400 rpm.

PubMed

Gil, Luiz Fernando; Sarendranath, Alvin; Neiva, Rodrigo; Marão, Heloisa F; Tovar, Nick; Bonfante, Estevam A; Janal, Malvin N; Castellano, Arthur; Coelho, Paulo G

This study evaluated whether simplified drilling protocols would provide comparable histologic and histomorphometric results to conventional drilling protocols at a low rotational speed. A total of 48 alumina-blasted and acid-etched Ti-6Al-4V implants with two diameters (3.75 and 4.2 mm, n = 24 per group) were bilaterally placed in the tibiae of 12 dogs, under a low-speed protocol (400 rpm). Within the same diameter group, half of the implants were inserted after a simplified drilling procedure (pilot drill + final diameter drill), and the other half were placed using the conventional drilling procedure. After 3 and 5 weeks, the animals were euthanized, and the retrieved bone-implant samples were subjected to nondecalcified histologic sectioning. Histomorphology, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) analysis were performed. Histology showed that new bone was formed around implants, and inflammation or bone resorption was not evident for both groups. Histomorphometrically, when all independent variables were collapsed over drilling technique, no differences were detected for BIC and BAFO; when drilling technique was analyzed as a function of time, the conventional groups reached statistically higher BIC and BAFO at 3 weeks, but comparable values between techniques were observed at 5 weeks; 4.2-mm implants obtained statistically higher BAFO relative to 3.75-mm implants. Based on the present methodology, the conventional technique improved bone formation at 3 weeks, and narrower implants were associated with less bone formation.

[Endoscopic full-thickness resection].

PubMed

Meier, B; Schmidt, A; Caca, K

2016-08-01

Conventional endoscopic resection techniques such as endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) are powerful tools for the treatment of gastrointestinal (GI) neoplasms. However, those techniques are limited to the superficial layers of the GI wall (mucosa and submucosa). Lesions without lifting sign (usually arising from deeper layers) or lesions in difficult anatomic positions (appendix, diverticulum) are difficult - if not impossible - to resect using conventional techniques, due to the increased risk of complications. For larger lesions (>2 cm), ESD appears to be superior to the conventional techniques because of the en bloc resection, but the procedure is technically challenging, time consuming, and associated with complications even in experienced hands. Since the development of the over-the-scope clips (OTSC), complications like bleeding or perforation can be endoscopically better managed. In recent years, different endoscopic full-thickness resection techniques came to the focus of interventional endoscopy. Since September 2014, the full-thickness resection device (FTRD) has the CE marking in Europe for full-thickness resection in the lower GI tract. Technically the device is based on the OTSC system and combines OTSC application and snare polypectomy in one step. This study shows all full-thickness resection techniques currently available, but clearly focuses on the experience with the FTRD in the lower GI tract.

Innovations in diagnostic imaging of localized prostate cancer.

PubMed

Pummer, Karl; Rieken, Malte; Augustin, Herbert; Gutschi, Thomas; Shariat, Shahrokh F

2014-08-01

In recent years, various imaging modalities have been developed to improve diagnosis, staging, and localization of early-stage prostate cancer (PCa). A MEDLINE literature search of the time frame between 01/2007 and 06/2013 was performed on imaging of localized PCa. Conventional transrectal ultrasound (TRUS) is mainly used to guide prostate biopsy. Contrast-enhanced ultrasound is based on the assumption that PCa tissue is hypervascularized and might be better identified after intravenous injection of a microbubble contrast agent. However, results on its additional value for cancer detection are controversial. Computer-based analysis of the transrectal ultrasound signal (C-TRUS) appears to detect cancer in a high rate of patients with previous biopsies. Real-time elastography seems to have higher sensitivity, specificity, and positive predictive value than conventional TRUS. However, the method still awaits prospective validation. The same is true for prostate histoscanning, an ultrasound-based method for tissue characterization. Currently, multiparametric MRI provides improved tissue visualization of the prostate, which may be helpful in the diagnosis and targeting of prostate lesions. However, most published series are small and suffer from variations in indication, methodology, quality, interpretation, and reporting. Among ultrasound-based techniques, real-time elastography and C-TRUS seem the most promising techniques. Multiparametric MRI appears to have advantages over conventional T2-weighted MRI in the detection of PCa. Despite these promising results, currently, no recommendation for the routine use of these novel imaging techniques can be made. Prospective studies defining the value of various imaging modalities are urgently needed.

Comparative Analysis Between Computed and Conventional Inferior Alveolar Nerve Block Techniques.

PubMed

Araújo, Gabriela Madeira; Barbalho, Jimmy Charles Melo; Dias, Tasiana Guedes de Souza; Santos, Thiago de Santana; Vasconcellos, Ricardo José de Holanda; de Morais, Hécio Henrique Araújo

2015-11-01

The aim of this randomized, double-blind, controlled trial was to compare the computed and conventional inferior alveolar nerve block techniques in symmetrically positioned inferior third molars. Both computed and conventional anesthetic techniques were performed in 29 healthy patients (58 surgeries) aged between 18 and 40 years. The anesthetic of choice was 2% lidocaine with 1: 200,000 epinephrine. The Visual Analogue Scale assessed the pain variable after anesthetic infiltration. Patient satisfaction was evaluated using the Likert Scale. Heart and respiratory rates, mean time to perform technique, and the need for additional anesthesia were also evaluated. Pain variable means were higher for the conventional technique as compared with computed, 3.45 ± 2.73 and 2.86 ± 1.96, respectively, but no statistically significant differences were found (P > 0.05). Patient satisfaction showed no statistically significant differences. The average computed technique runtime and the conventional were 3.85 and 1.61 minutes, respectively, showing statistically significant differences (P <0.001). The computed anesthetic technique showed lower mean pain perception, but did not show statistically significant differences when contrasted to the conventional technique.

Adherence of Candida to complete denture surfaces in vitro: A comparison of conventional and CAD/CAM complete dentures

PubMed Central

Al-mejrad, Lamya A.; Albarrag, Ahmed M.

2017-01-01

PURPOSE The goal of this study was to compare the adhesion of Candida albicans to the surfaces of CAD/CAM and conventionally fabricated complete denture bases. MATERIALS AND METHODS Twenty discs of acrylic resin poly (methyl methacrylate) were fabricated with CAD/CAM and conventional procedures (heat-polymerized acrylic resin). The specimens were divided into two groups: 10 discs were fabricated using the CAD/CAM procedure (Wieland Digital Denture Ivoclar Vivadent), and 10 discs were fabricated using a conventional flasking and pressure-pack technique. Candida colonization was performed on all the specimens using four Candida albicans isolates. The difference in Candida albicans adhesion on the discs was evaluated. The number of adherent yeast cells was calculated by the colony-forming units (CFU) and by Fluorescence microscopy. RESULTS There was a significant difference in the adhesion of Candida albicans to the complete denture bases created with CAD/CAM and the adhesion to those created with the conventional procedure. The CAD/CAM denture bases exhibited less adhesion of Candida albicans than did the denture bases created with the conventional procedure (P<.05). CONCLUSION The CAD/CAM procedure for fabricating complete dentures showed promising potential for reducing the adherence of Candida to the denture base surface. Clinical Implications. Complete dentures made with the CAD/CAM procedure might decrease the incidence of denture stomatitis compared with conventional dentures. PMID:29142649

Adherence of Candida to complete denture surfaces in vitro: A comparison of conventional and CAD/CAM complete dentures.

PubMed

Al-Fouzan, Afnan F; Al-Mejrad, Lamya A; Albarrag, Ahmed M

2017-10-01

The goal of this study was to compare the adhesion of Candida albicans to the surfaces of CAD/CAM and conventionally fabricated complete denture bases. Twenty discs of acrylic resin poly (methyl methacrylate) were fabricated with CAD/CAM and conventional procedures (heat-polymerized acrylic resin). The specimens were divided into two groups: 10 discs were fabricated using the CAD/CAM procedure (Wieland Digital Denture Ivoclar Vivadent), and 10 discs were fabricated using a conventional flasking and pressure-pack technique. Candida colonization was performed on all the specimens using four Candida albicans isolates. The difference in Candida albicans adhesion on the discs was evaluated. The number of adherent yeast cells was calculated by the colony-forming units (CFU) and by Fluorescence microscopy. There was a significant difference in the adhesion of Candida albicans to the complete denture bases created with CAD/CAM and the adhesion to those created with the conventional procedure. The CAD/CAM denture bases exhibited less adhesion of Candida albicans than did the denture bases created with the conventional procedure ( P <.05). The CAD/CAM procedure for fabricating complete dentures showed promising potential for reducing the adherence of Candida to the denture base surface. Clinical Implications. Complete dentures made with the CAD/CAM procedure might decrease the incidence of denture stomatitis compared with conventional dentures.

Brain-computer interface: changes in performance using virtual reality techniques.

PubMed

Ron-Angevin, Ricardo; Díaz-Estrella, Antonio

2009-01-09

The ability to control electroencephalographic (EEG) signals when different mental tasks are carried out would provide a method of communication for people with serious motor function problems. This system is known as a brain-computer interface (BCI). Due to the difficulty of controlling one's own EEG signals, a suitable training protocol is required to motivate subjects, as it is necessary to provide some type of visual feedback allowing subjects to see their progress. Conventional systems of feedback are based on simple visual presentations, such as a horizontal bar extension. However, virtual reality is a powerful tool with graphical possibilities to improve BCI-feedback presentation. The objective of the study is to explore the advantages of the use of feedback based on virtual reality techniques compared to conventional systems of feedback. Sixteen untrained subjects, divided into two groups, participated in the experiment. A group of subjects was trained using a BCI system, which uses conventional feedback (bar extension), and another group was trained using a BCI system, which submits subjects to a more familiar environment, such as controlling a car to avoid obstacles. The obtained results suggest that EEG behaviour can be modified via feedback presentation. Significant differences in classification error rates between both interfaces were obtained during the feedback period, confirming that an interface based on virtual reality techniques can improve the feedback control, specifically for untrained subjects.

A novel rapid genotyping technique for Collie eye anomaly: SYBR Green-based real-time polymerase chain reaction method applicable to blood and saliva specimens on Flinders Technology Associates filter paper.

PubMed

Chang, Hye-Sook; Mizukami, Keijiro; Yabuki, Akira; Hossain, Mohammad A; Rahman, Mohammad M; Uddin, Mohammad M; Arai, Toshiro; Yamato, Osamu

2010-09-01

Collie eye anomaly (CEA) is a canine inherited ocular disease that shows a wide variety of manifestations and severity of clinical lesions. Recently, a CEA-associated mutation was reported, and a DNA test that uses conventional polymerase chain reaction (PCR) has now become available. The objective of the current study was to develop a novel rapid genotyping technique by using SYBR Green-based real-time PCR for future large-scale surveys as a key part in the strategy to eradicate CEA by selective breeding. First, a SYBR Green-based real-time PCR assay for genotyping of CEA was developed and evaluated by using purified DNA samples from normal, carrier, and affected Border Collies in which genotypes had previously been determined by conventional PCR. This real-time PCR assay demonstrated appropriate amplifications in all genotypes, and the results were consistent with those of conventional PCR. Second, the availability of Flinders Technology Associates filter paper (FTA card) as DNA templates for the real-time PCR assay was evaluated by using blood and saliva specimens to determine suitability for CEA screening. DNA-containing solution prepared from a disc of blood- or saliva-spotted FTA cards was available directly as templates for the real-time PCR assay when the volume of solution was 2.5% of the PCR mixture. In conclusion, SYBR Green-based real-time PCR combined with FTA cards is a rapid genotyping technique for CEA that can markedly shorten the overall time required for genotyping as well as simplify the sample preparation. Therefore, this newly developed technique suits large-scale screening in breeding populations of Collie-related breeds.

Combination of DNA-based and conventional methods to detect human leukocyte antigen polymorphism and its use for paternity testing.

PubMed

Kereszturya, László; Rajczya, Katalin; Lászikb, András; Gyódia, Eva; Pénzes, Mária; Falus, András; Petrányia, Gyõzõ G

2002-03-01

In cases of disputed paternity, the scientific goal is to promote either the exclusion of a falsely accused man or the affiliation of the alleged father. Until now, in addition to anthropologic characteristics, the determination of genetic markers included human leukocyte antigen gene variants; erythrocyte antigens and serum proteins were used for that reason. Recombinant DNA techniques provided a new set of highly variable genetic markers based on DNA nucleotide sequence polymorphism. From the practical standpoint, the application of these techniques to paternity testing provides greater versatility than do conventional genetic marker systems. The use of methods to detect the polymorphism of human leukocyte antigen loci significantly increases the chance of validation of ambiguous results in paternity testing. The outcome of 2384 paternity cases investigated by serologic and/or DNA-based human leukocyte antigen typing was statistically analyzed. Different cases solved by DNA typing are presented involving cases with one or two accused men, exclusions and nonexclusions, and tests of the paternity of a deceased man. The results provide evidence for the advantage of the combined application of various techniques in forensic diagnostics and emphasizes the outstanding possibilities of DNA-based assays. Representative examples demonstrate the strength of combined techniques in paternity testing.

MANTA, a novel plug-based vascular closure device for large bore arteriotomies: technical report.

PubMed

van Gils, Lennart; Daemen, Joost; Walters, Greg; Sorzano, Todd; Grintz, Todd; Nardone, Sam; Lenzen, Mattie; De Jaegere, Peter P T; Roubin, Gary; Van Mieghem, Nicolas M

2016-09-18

Catheter-based interventions have become a less invasive alternative to conventional surgical techniques for a wide array of cardiovascular diseases but often create large arteriotomies. A completely percutaneous technique is attractive as it may reduce the overall complication rate and procedure time. Currently, large bore arteriotomy closure relies on suture-based techniques. Access-site complications are not uncommon and often seem related to closure device failure. The MANTA VCD is a novel collagen-based closure device that specifically targets arteriotomies between 10 and 22 Fr. This technical report discusses the MANTA design concept, practical instructions for use and preliminary clinical experience.

Application of thin layer activation technique for surface wear studies in Zr based materials using charged particle induced nuclear reactions

NASA Astrophysics Data System (ADS)

Chowdhury, D. P.; Pal, Sujit; Parthasarathy, R.; Mathur, P. K.; Kohli, A. K.; Limaye, P. K.

1998-09-01

Thin layer activation (TLA) technique has been developed in Zr based alloy materials, e.g., zircaloy II, using 40 MeV α-particles from Variable Energy Cyclotron Centre at Calcutta. A brief description of the methodology of TLA technique is presented to determine the surface wear. The sensitivity of the measurement of surface wear in zircaloy material is found to be 0.22±0.05 μm. The surface wear is determined by TLA technique in zircaloy material which is used in pressurised heavy water reactor and the values have been compared with that obtained by conventional technique for the analytical validation of the TLA technique.

Wavelet Transform Based Filter to Remove the Notches from Signal Under Harmonic Polluted Environment

NASA Astrophysics Data System (ADS)

Das, Sukanta; Ranjan, Vikash

2017-12-01

The work proposes to annihilate the notches present in the synchronizing signal required for converter operation appearing due to switching of semiconductor devices connected to the system in the harmonic polluted environment. The disturbances in the signal are suppressed by wavelet based novel filtering technique. In the proposed technique, the notches in the signal are determined and eliminated by the wavelet based multi-rate filter using `Daubechies4' (db4) as mother wavelet. The computational complexity of the adapted technique is very less as compared to any other conventional notch filtering techniques. The proposed technique is developed in MATLAB/Simulink and finally validated with dSPACE-1103 interface. The recovered signal, thus obtained, is almost free of the notches.

Experimental validation of spatial Fourier transform-based multiple sound zone generation with a linear loudspeaker array.

PubMed

Okamoto, Takuma; Sakaguchi, Atsushi

2017-03-01

Generating acoustically bright and dark zones using loudspeakers is gaining attention as one of the most important acoustic communication techniques for such uses as personal sound systems and multilingual guide services. Although most conventional methods are based on numerical solutions, an analytical approach based on the spatial Fourier transform with a linear loudspeaker array has been proposed, and its effectiveness has been compared with conventional acoustic energy difference maximization and presented by computer simulations. To describe the effectiveness of the proposal in actual environments, this paper investigates the experimental validation of the proposed approach with rectangular and Hann windows and compared it with three conventional methods: simple delay-and-sum beamforming, contrast maximization, and least squares-based pressure matching using an actually implemented linear array of 64 loudspeakers in an anechoic chamber. The results of both the computer simulations and the actual experiments show that the proposed approach with a Hann window more accurately controlled the bright and dark zones than the conventional methods.

Performance and cost analysis of Siriraj liquid-based cytology: a direct-to-vial study.

PubMed

Laiwejpithaya, Somsak; Benjapibal, Mongkol; Laiwejpithaya, Sujera; Wongtiraporn, Weerasak; Sangkarat, Suthi; Rattanachaiyanont, Manee

2009-12-01

To compare the cytological diagnoses, specimen adequacy, and cost of the Siriraj liquid-based cytology (LBC) with those of the conventional smear technique. An observational study with historical comparison was conducted in a tertiary university hospital. Cytological reports of 23,676 Siriraj-LBC specimens obtained in 2006 were compared with those of 25,510 conventional smears obtained in 2004. Overall prevalence of abnormal cervical cytology detected by conventional smear was 1.76% and by Siriraj-LBC was 3.70%. Compared with the conventional method, the Siriraj-LBC yielded a significantly higher overall detection rate of abnormal cervical cytology, with a 110.23% increase in the detection rate (P<0.001), mainly due to the increase in diagnosis of squamous intraepithelial lesions (SIL), both low and high grade, together with atypical squamous cells of undetermined significance, "atypical squamous cells cannot exclude HSIL", and malignancies, but not atypical glandular cells. The Siriraj-LBC had a smaller proportion of unsatisfactory slides (4.94% vs. 18.60%, P<0.001) and a higher negative predictive value (96.33% vs. 92.74%, P=0.001), but no difference in positive predictive value (83.03% vs. 86.83%, P=0.285). The cost of Siriraj-LBC was approximately 67% higher than that of the conventional cytology used in Siriraj Hospital and 50-70% lower than that of the commercially available LBC techniques in Thailand. The Siriraj-LBC increases the detection rate of abnormal cytology, improves specimen adequacy, and enhances the negative predictive value without compromising the positive predictive value. For centers where conventional Pap smear does not perform well, the introduction of a low cost Siriraj-LBC might help to improve performance and it may be an economical alternative to the commercially available liquid-based cytology.

Office-based narrow band imaging-guided flexible laryngoscopy tissue sampling: A cost-effectiveness analysis evaluating its impact on Taiwanese health insurance program.

PubMed

Fang, Tuan-Jen; Li, Hsueh-Yu; Liao, Chun-Ta; Chiang, Hui-Chen; Chen, I-How

2015-07-01

Narrow band imaging (NBI)-guided flexible laryngoscopy tissue sampling for laryngopharyngeal lesions is a novel technique. Patients underwent the procedure in an office-based setting without being sedated, which is different from the conventional technique performed using direct laryngoscopy. Although the feasibility and effects of this procedure were established, its financial impact on the institution and Taiwanese National Health Insurance program was not determined. This is a retrospective case-control study. From May 2010 to April 2011, 20 consecutive patients who underwent NBI flexible laryngoscopy tissue sampling were recruited. During the same period, another 20 age-, sex-, and lesion-matched cases were enrolled in the control group. The courses for procedures and financial status were analyzed and compared between groups. Office-based NBI flexible laryngoscopy tissue sampling procedure took 27 minutes to be completed, while 191 minutes were required for the conventional technique. Average reimbursement for each case was New Taiwan Dollar (NT$)1264 for patients undergoing office-based NBI flexible laryngoscopy tissue sampling, while NT$10,913 for those undergoing conventional direct laryngoscopy in the operation room (p < 0.001). The institution suffered a loss of at least NT$690 when performing NBI flexible laryngoscopy tissue sampling. Office-based NBI flexible laryngoscopy tissue sampling is a cost-saving procedure for patients and the Taiwanese National Health Insurance program. It also saves the procedure time. However, the net financial loss for the institution and physician would limit its popularization unless reimbursement patterns are changed. Copyright © 2013. Published by Elsevier B.V.

Use of activity theory-based need finding for biomedical device development.

PubMed

Rismani, Shalaleh; Ratto, Matt; Machiel Van der Loos, H F

2016-08-01

Identifying the appropriate needs for biomedical device design is challenging, especially for less structured environments. The paper proposes an alternate need-finding method based on Cultural Historical Activity Theory and expanded to explicitly examine the role of devices within a socioeconomic system. This is compared to a conventional need-finding technique in a preliminary study with engineering student teams. The initial results show that the Activity Theory-based technique allows teams to gain deeper insights into their needs space.

Fostering Sustainable Behavior: An Introduction to Community-Based Social Marketing.

ERIC Educational Resources Information Center

McKenzie-Mohr, Doug; Smith, William

This book discusses incorporating community-based social marketing techniques programs. The first chapter explains why programs that rely heavily on conventional methods to promote behavior change are often ineffective, and introduces community-based social marketing as an attractive alternative for the delivery of programs. Chapter 2 describes…

Fiber-Optic Surface Temperature Sensor Based on Modal Interference.

PubMed

Musin, Frédéric; Mégret, Patrice; Wuilpart, Marc

2016-07-28

Spatially-integrated surface temperature sensing is highly useful when it comes to controlling processes, detecting hazardous conditions or monitoring the health and safety of equipment and people. Fiber-optic sensing based on modal interference has shown great sensitivity to temperature variation, by means of cost-effective image-processing of few-mode interference patterns. New developments in the field of sensor configuration, as described in this paper, include an innovative cooling and heating phase discrimination functionality and more precise measurements, based entirely on the image processing of interference patterns. The proposed technique was applied to the measurement of the integrated surface temperature of a hollow cylinder and compared with a conventional measurement system, consisting of an infrared camera and precision temperature probe. As a result, the optical technique is in line with the reference system. Compared with conventional surface temperature probes, the optical technique has the following advantages: low heat capacity temperature measurement errors, easier spatial deployment, and replacement of multiple angle infrared camera shooting and the continuous monitoring of surfaces that are not visually accessible.

Review of quantitative ultrasound: envelope statistics and backscatter coefficient imaging and contributions to diagnostic ultrasound

PubMed Central

Oelze, Michael L.; Mamou, Jonathan

2017-01-01

Conventional medical imaging technologies, including ultrasound, have continued to improve over the years. For example, in oncology, medical imaging is characterized by high sensitivity, i.e., the ability to detect anomalous tissue features, but the ability to classify these tissue features from images often lacks specificity. As a result, a large number of biopsies of tissues with suspicious image findings are performed each year with a vast majority of these biopsies resulting in a negative finding. To improve specificity of cancer imaging, quantitative imaging techniques can play an important role. Conventional ultrasound B-mode imaging is mainly qualitative in nature. However, quantitative ultrasound (QUS) imaging can provide specific numbers related to tissue features that can increase the specificity of image findings leading to improvements in diagnostic ultrasound. QUS imaging techniques can encompass a wide variety of techniques including spectral-based parameterization, elastography, shear wave imaging, flow estimation and envelope statistics. Currently, spectral-based parameterization and envelope statistics are not available on most conventional clinical ultrasound machines. However, in recent years QUS techniques involving spectral-based parameterization and envelope statistics have demonstrated success in many applications, providing additional diagnostic capabilities. Spectral-based techniques include the estimation of the backscatter coefficient, estimation of attenuation, and estimation of scatterer properties such as the correlation length associated with an effective scatterer diameter and the effective acoustic concentration of scatterers. Envelope statistics include the estimation of the number density of scatterers and quantification of coherent to incoherent signals produced from the tissue. Challenges for clinical application include correctly accounting for attenuation effects and transmission losses and implementation of QUS on clinical devices. Successful clinical and pre-clinical applications demonstrating the ability of QUS to improve medical diagnostics include characterization of the myocardium during the cardiac cycle, cancer detection, classification of solid tumors and lymph nodes, detection and quantification of fatty liver disease, and monitoring and assessment of therapy. PMID:26761606

Biomechanical comparison of the double-push technique and the conventional skate skiing technique in cross-country sprint skiing.

PubMed

Stöggl, Thomas; Müller, Erich; Lindinger, Stefan

2008-09-01

The aims of the study were to: (1) adapt the "double-push" technique from inline skating to cross-country skiing; (2) compare this new skiing technique with the conventional skate skiing cross-country technique; and (3) test the hypothesis that the double-push technique improves skiing speed in a short sprint. 13 elite skiers performed maximum-speed sprints over 100 m using the double-push skate skiing technique and using the conventional "V2" skate skiing technique. Pole and plantar forces, knee angle, cycle characteristics, and electromyography of nine lower body muscles were analysed. We found that the double-push technique could be successfully transferred to cross-country skiing, and that this new technique is faster than the conventional skate skiing technique. The double-push technique was 2.9 +/- 2.2% faster (P < 0.001), which corresponds to a time advantage of 0.41 +/- 0.31 s over 100 m. The double-push technique had a longer cycle length and a lower cycle rate, and it was characterized by higher muscle activity, higher knee extension amplitudes and velocities, and higher peak foot forces, especially in the first phase of the push-off. Also, the foot was more loaded laterally in the double-push technique than in the conventional skate skiing technique.

Comparison of Implant Stability Using Resonance Frequency Analysis: Osteotome Versus Conventional Drilling

PubMed Central

Sadeghi, Rokhsareh; Miremadi, Asghar

2015-01-01

Objectives: Implant primary stability is one of the important factors in achieving implant success. The osteotome technique may improve primary stability in patients with poor bone quality. The aim of this study was to compare implant stability using two different techniques namely osteotome versus conventional drilling in the posterior maxilla. Materials and Methods: In this controlled randomized clinical trial, 54 dental implants were placed in 32 patients; 29 implants were placed in the osteotome group and 25 in the conventional drilling group. Implant stability was assessed at four time intervals namely at baseline, one, two and three months after implant placement using resonance frequency analysis (RFA). Results: Primary stability based on implant stability quotient (ISQ) units was 71.4±7 for the osteotome group and 67.4±10 for the control group. There was no statistically significant difference between the two groups in implant stability at any of the measurement times. In each group, changes in implant stability from baseline to one month and also from two months to three months post-operatively were not significant but from one month to two months after implant placement, implant stability showed a significant increase in both groups. Conclusion: The results of this study revealed that in both techniques, good implant stability was achieved and osteotome technique did not have any advantage compared to conventional drilling in this regard. PMID:27148375

A Simplified Technique for Implant-Abutment Level Impression after Soft Tissue Adaptation around Provisional Restoration

PubMed Central

Kutkut, Ahmad; Abu-Hammad, Osama; Frazer, Robert

2016-01-01

Impression techniques for implant restorations can be implant level or abutment level impressions with open tray or closed tray techniques. Conventional implant-abutment level impression techniques are predictable for maximizing esthetic outcomes. Restoration of the implant traditionally requires the use of the metal or plastic impression copings, analogs, and laboratory components. Simplifying the dental implant restoration by reducing armamentarium through incorporating conventional techniques used daily for crowns and bridges will allow more general dentists to restore implants in their practices. The demonstrated technique is useful when modifications to implant abutments are required to correct the angulation of malpositioned implants. This technique utilizes conventional crown and bridge impression techniques. As an added benefit, it reduces costs by utilizing techniques used daily for crowns and bridges. The aim of this report is to describe a simplified conventional impression technique for custom abutments and modified prefabricated solid abutments for definitive restorations. PMID:29563457

A demonstration of a transportable radio interferometric surveying system with 3-cm accuracy on a 307-m base line

NASA Technical Reports Server (NTRS)

Ong, K. M.; Macdoran, P. F.; Thomas, J. B.; Fliegel, H. F.; Skjerve, L. J.; Spitzmesser, D. J.; Batelaan, P. D.; Paine, S. R.; Newsted, M. G.

1976-01-01

A precision geodetic measurement system (Aries, for Astronomical Radio Interferometric Earth Surveying) based on the technique of very long base line interferometry has been designed and implemented through the use of a 9-m transportable antenna and the NASA 64-m antenna of the Deep Space Communications Complex at Goldstone, California. A series of experiments designed to demonstrate the inherent accuracy of a transportable interferometer was performed on a 307-m base line during the period from December 1973 to June 1974. This short base line was chosen in order to obtain a comparison with a conventional survey with a few-centimeter accuracy and to minimize Aries errors due to transmission media effects, source locations, and earth orientation parameters. The base-line vector derived from a weighted average of the measurements, representing approximately 24 h of data, possessed a formal uncertainty of about 3 cm in all components. This average interferometry base-line vector was in good agreement with the conventional survey vector within the statistical range allowed by the combined uncertainties (3-4 cm) of the two techniques.

Charge plasma technique based dopingless accumulation mode junctionless cylindrical surrounding gate MOSFET: analog performance improvement

NASA Astrophysics Data System (ADS)

Trivedi, Nitin; Kumar, Manoj; Haldar, Subhasis; Deswal, S. S.; Gupta, Mridula; Gupta, R. S.

2017-09-01

A charge plasma technique based dopingless (DL) accumulation mode (AM) junctionless (JL) cylindrical surrounding gate (CSG) MOSFET has been proposed and extensively investigated. Proposed device has no physical junction at source to channel and channel to drain interface. The complete silicon pillar has been considered as undoped. The high free electron density or induced N+ region is designed by keeping the work function of source/drain metal contacts lower than the work function of undoped silicon. Thus, its fabrication complexity is drastically reduced by curbing the requirement of high temperature doping techniques. The electrical/analog characteristics for the proposed device has been extensively investigated using the numerical simulation and are compared with conventional junctionless cylindrical surrounding gate (JL-CSG) MOSFET with identical dimensions. For the numerical simulation purpose ATLAS-3D device simulator is used. The results show that the proposed device is more short channel immune to conventional JL-CSG MOSFET and suitable for faster switching applications due to higher I ON/ I OFF ratio.

Visualizing Molecular Diffusion through Passive Permeability Barriers in Cells: Conventional and Novel Approaches

PubMed Central

Lin, Yu-Chun; Phua, Siew Cheng; Lin, Benjamin; Inoue, Takanari

2013-01-01

Diffusion barriers are universal solutions for cells to achieve distinct organizations, compositions, and activities within a limited space. The influence of diffusion barriers on the spatiotemporal dynamics of signaling molecules often determines cellular physiology and functions. Over the years, the passive permeability barriers in various subcellular locales have been characterized using elaborate analytical techniques. In this review, we will summarize the current state of knowledge on the various passive permeability barriers present in mammalian cells. We will conclude with a description of several conventional techniques and one new approach based on chemically-inducible diffusion trap (C-IDT) for probing permeable barriers. PMID:23731778

Interference Resilient Sigma Delta-Based Pulse Oximeter.

PubMed

Shokouhian, Mohsen; Morling, Richard; Kale, Izzet

2016-06-01

Ambient light and optical interference can severely affect the performance of pulse oximeters. The deployment of a robust modulation technique to drive the pulse oximeter LEDs can reduce these unwanted effects and increases the resilient of the pulse oximeter against artificial ambient light. The time division modulation technique used in conventional pulse oximeters can not remove the effect of modulated light coming from surrounding environment and this may cause huge measurement error in pulse oximeter readings. This paper presents a novel cross-coupled sigma delta modulator which ensures that measurement accuracy will be more robust in comparison with conventional fixed-frequency oximeter modulation technique especially in the presence of pulsed artificial ambient light. Moreover, this novel modulator gives an extra control over the pulse oximeter power consumption leading to improved power management.

Simulations of multi-contrast x-ray imaging using near-field speckles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zdora, Marie-Christine; Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom and Department of Physics & Astronomy, University College London, London, WC1E 6BT; Thibault, Pierre

2016-01-28

X-ray dark-field and phase-contrast imaging using near-field speckles is a novel technique that overcomes limitations inherent in conventional absorption x-ray imaging, i.e. poor contrast for features with similar density. Speckle-based imaging yields a wealth of information with a simple setup tolerant to polychromatic and divergent beams, and simple data acquisition and analysis procedures. Here, we present a simulation software used to model the image formation with the speckle-based technique, and we compare simulated results on a phantom sample with experimental synchrotron data. Thorough simulation of a speckle-based imaging experiment will help for better understanding and optimising the technique itself.

Critical review of analytical techniques for safeguarding the thorium-uranium fuel cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hakkila, E.A.

1978-10-01

Conventional analytical methods applicable to the determination of thorium, uranium, and plutonium in feed, product, and waste streams from reprocessing thorium-based nuclear reactor fuels are reviewed. Separations methods of interest for these analyses are discussed. Recommendations concerning the applicability of various techniques to reprocessing samples are included. 15 tables, 218 references.

Characterization of the Hydrocarbon Potential and Non-Potential Zones Using Wavelet-Based Fractal Analysis

NASA Astrophysics Data System (ADS)

Mukherjee, Bappa; Roy, P. N. S.

The identification of prospective and dry zone is of major importance from well log data. Truthfulness in the identification of potential zone is a very crucial issue in hydrocarbon exploration. In this line, the problem has received considerable attention and many conventional techniques have been proposed. The purpose of this study is to recognize the hydrocarbon and non-hydrocarbon bearing portion within a reservoir by using the non-conventional technique. The wavelet based fractal analysis (WBFA) has been applied on the wire-line log data in order to obtain the pre-defined hydrocarbon (HC) and non-hydrocarbon (NHC) zones by their self-affine signal nature is demonstrated in this paper. The feasibility of the proposed technique is tested with the help of most commonly used logs, like self-potential, gamma ray, resistivity and porosity log responses. These logs are obtained from the industry to make out several HC and NHC zones of all wells in the study region belonging to the upper Assam basin. The results obtained in this study for a particular log response, where in the case of HC bearing zones, it is found that they are mainly situated in a variety of sandstones lithology which leads to the higher Hurst exponent. Further, the NHC zones found to be analogous to lithology with higher shale content having lower Hurst exponent. The above proposed technique can overcome the chance of miss interpretation in conventional reservoir characterization.

Large area fabrication of plasmonic nanoparticle grating structure by conventional scanning electron microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Rai, V. N.

Plasmonic nanoparticle grating (PNG) structure of different periods has been fabricated by electron beam lithography using silver halide based transmission electron microscope film as a substrate. Conventional scanning electron microscope is used as a fabrication tool for electron beam lithography. Optical microscope and energy dispersive spectroscopy (EDS) have been used for its morphological and elemental characterization. Optical characterization is performed by UV-Vis absorption spectroscopic technique.

TiO2-coated mesoporous carbon: conventional vs. microwave-annealing process.

PubMed

Coromelci-Pastravanu, Cristina; Ignat, Maria; Popovici, Evelini; Harabagiu, Valeria

2014-08-15

The study of coating mesoporous carbon materials with titanium oxide nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon materials in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of mesoporous carbon materials and titanium oxide is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. But, their synthesis is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors, which takes time and money. The thermal heating based techniques are time consuming and often lack control of particle size and morphology. Hence, since there is a growing interest in microwave technology, an alternative way of power input into chemical reactions through dielectric heating is the use of microwaves. This work is focused on the advantages of microwave-assisted synthesis of TiO2-coated mesoporous carbon over conventional thermal heating method. The reviewed studies showed that the microwave-assisted synthesis of such composites allows processes to be completed within a shorter reaction time allowing the nanoparticles formation with superior properties than that obtained by conventional method. Copyright © 2014 Elsevier B.V. All rights reserved.

Applications of artificial intelligence to mission planning

NASA Technical Reports Server (NTRS)

Ford, Donnie R.; Rogers, John S.; Floyd, Stephen A.

1990-01-01

The scheduling problem facing NASA-Marshall mission planning is extremely difficult for several reasons. The most critical factor is the computational complexity involved in developing a schedule. The size of the search space is large along some dimensions and infinite along others. It is because of this and other difficulties that many of the conventional operation research techniques are not feasible or inadequate to solve the problems by themselves. Therefore, the purpose is to examine various artificial intelligence (AI) techniques to assist conventional techniques or to replace them. The specific tasks performed were as follows: (1) to identify mission planning applications for object oriented and rule based programming; (2) to investigate interfacing AI dedicated hardware (Lisp machines) to VAX hardware; (3) to demonstrate how Lisp may be called from within FORTRAN programs; (4) to investigate and report on programming techniques used in some commercial AI shells, such as Knowledge Engineering Environment (KEE); and (5) to study and report on algorithmic methods to reduce complexity as related to AI techniques.

A CMOS camera-based system for clinical photoplethysmographic applications

NASA Astrophysics Data System (ADS)

Humphreys, Kenneth; Markham, Charles; Ward, Tomas E.

2005-06-01

In this work an image-based photoplethysmography (PPG) system is developed and tested against a conventional finger-based system as commonly used in clinical practise. A PPG is essentially an optical instrument consisting of a near infrared (NIR) source and detector that is capable of tracking blood flow changes in body tissue. When used with a number of wavelengths in the NIR band blood oxygenation changes as well as other blood chemical signatures can be ascertained yielding a very useful device in the clinical realm. Conventionally such a device requires direct contact with the tissue under investigation which eliminates the possibility of its use for applications like wound management where the tissue oxygenation measurement could be extremely useful. To circumnavigate this shortcoming we have developed a CMOS camera-based system, which can successfully extract the PPG signal without contact with the tissue under investigation. A comparison of our results with conventional techniques has yielded excellent results.

The role of FDG PET/CT in patients with locoregional breast cancer recurrence: a comparison to conventional imaging techniques.

PubMed

Aukema, T S; Rutgers, E J Th; Vogel, W V; Teertstra, H J; Oldenburg, H S; Vrancken Peeters, M T F D; Wesseling, J; Russell, N S; Valdés Olmos, R A

2010-04-01

The aim of this study was to evaluate the impact of (18)F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) on clinical management in patients with locoregional breast cancer recurrence amenable for locoregional treatment and to compare the PET/CT results with the conventional imaging data. From January 2006 to August 2008, all patients with locoregional breast cancer recurrence underwent whole-body PET/CT. PET/CT findings were compared with results of the conventional imaging techniques and final pathology. The impact of PET/CT results on clinical management was evaluated based on clinical decisions obtained from patient files. 56 patients were included. In 32 patients (57%) PET/CT revealed additional tumour localisations. Distant metastases were detected in 11 patients on conventional imaging and in 23 patients on PET/CT images (p < 0.01). In 25 patients (45%), PET/CT detected additional lesions not visible on conventional imaging. PET/CT had an impact on clinical management in 27 patients (48%) by detecting more extensive locoregional disease or distant metastases. In 20 patients (36%) extensive surgery was prevented and treatment was changed to palliative treatment. The sensitivity, specificity, accuracy, positive and negative predictive values of FDG PET/CT were respectively 97%, 92%, 95%, 94% and 96%. PET/CT, in addition to conventional imaging techniques, plays an important role in staging patients with locoregional breast cancer recurrence since its result changed the clinical management in almost half of the patients. PET/CT could potentially replace conventional staging imaging in patients with a locoregional breast cancer recurrence. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

An Approach to V&V of Embedded Adaptive Systems

NASA Technical Reports Server (NTRS)

Liu, Yan; Yerramalla, Sampath; Fuller, Edgar; Cukic, Bojan; Gururajan, Srikaruth

2004-01-01

Rigorous Verification and Validation (V&V) techniques are essential for high assurance systems. Lately, the performance of some of these systems is enhanced by embedded adaptive components in order to cope with environmental changes. Although the ability of adapting is appealing, it actually poses a problem in terms of V&V. Since uncertainties induced by environmental changes have a significant impact on system behavior, the applicability of conventional V&V techniques is limited. In safety-critical applications such as flight control system, the mechanisms of change must be observed, diagnosed, accommodated and well understood prior to deployment. In this paper, we propose a non-conventional V&V approach suitable for online adaptive systems. We apply our approach to an intelligent flight control system that employs a particular type of Neural Networks (NN) as the adaptive learning paradigm. Presented methodology consists of a novelty detection technique and online stability monitoring tools. The novelty detection technique is based on Support Vector Data Description that detects novel (abnormal) data patterns. The Online Stability Monitoring tools based on Lyapunov's Stability Theory detect unstable learning behavior in neural networks. Cases studies based on a high fidelity simulator of NASA's Intelligent Flight Control System demonstrate a successful application of the presented V&V methodology. ,

A timer inventory based upon manual and automated analysis of ERTS-1 and supporting aircraft data using multistage probability sampling. [Plumas National Forest, California

NASA Technical Reports Server (NTRS)

Nichols, J. D.; Gialdini, M.; Jaakkola, S.

1974-01-01

A quasi-operational study demonstrating that a timber inventory based on manual and automated analysis of ERTS-1, supporting aircraft data and ground data was made using multistage sampling techniques. The inventory proved to be a timely, cost effective alternative to conventional timber inventory techniques. The timber volume on the Quincy Ranger District of the Plumas National Forest was estimated to be 2.44 billion board feet with a sampling error of 8.2 percent. Costs per acre for the inventory procedure at 1.1 cent/acre compared favorably with the costs of a conventional inventory at 25 cents/acre. A point-by-point comparison of CALSCAN-classified ERTS data with human-interpreted low altitude photo plots indicated no significant differences in the overall classification accuracies.

Patch-Based Super-Resolution of MR Spectroscopic Images: Application to Multiple Sclerosis

PubMed Central

Jain, Saurabh; Sima, Diana M.; Sanaei Nezhad, Faezeh; Hangel, Gilbert; Bogner, Wolfgang; Williams, Stephen; Van Huffel, Sabine; Maes, Frederik; Smeets, Dirk

2017-01-01

Purpose: Magnetic resonance spectroscopic imaging (MRSI) provides complementary information to conventional magnetic resonance imaging. Acquiring high resolution MRSI is time consuming and requires complex reconstruction techniques. Methods: In this paper, a patch-based super-resolution method is presented to increase the spatial resolution of metabolite maps computed from MRSI. The proposed method uses high resolution anatomical MR images (T1-weighted and Fluid-attenuated inversion recovery) to regularize the super-resolution process. The accuracy of the method is validated against conventional interpolation techniques using a phantom, as well as simulated and in vivo acquired human brain images of multiple sclerosis subjects. Results: The method preserves tissue contrast and structural information, and matches well with the trend of acquired high resolution MRSI. Conclusions: These results suggest that the method has potential for clinically relevant neuroimaging applications. PMID:28197066

Design and fabrication of conventional and unconventional superconductors

NASA Technical Reports Server (NTRS)

Collings, E. W.

1983-01-01

The design and fabrication of conventional and unconventionally processed Ti-Nb base and Al5-compound-base, respectively, composite superconductors is discussed in a nine section review. The first two sections introduce the general properties of alloy and compound superconductors, and the design and processing requirements for the production of long lengths of stable low loss conductor. All aspects of flux jump stability, and the general requirements of cryogenic stabilization are addressed. Conductor design from an a.c.-loss standpoint; some basic formulae describing hysteretic and eddy current losses and the influences on a.c. loss of filament diameter, strand (conductor) diameter, twist pitch, and matrix resistivity are discussed. The basic techniques used in the fabrication of conventional multifilamentary conductors are described.

Comparison of digital and conventional impression techniques: evaluation of patients' perception, treatment comfort, effectiveness and clinical outcomes.

PubMed

Yuzbasioglu, Emir; Kurt, Hanefi; Turunc, Rana; Bilir, Halenur

2014-01-30

The purpose of this study was to compare two impression techniques from the perspective of patient preferences and treatment comfort. Twenty-four (12 male, 12 female) subjects who had no previous experience with either conventional or digital impression participated in this study. Conventional impressions of maxillary and mandibular dental arches were taken with a polyether impression material (Impregum, 3 M ESPE), and bite registrations were made with polysiloxane bite registration material (Futar D, Kettenbach). Two weeks later, digital impressions and bite scans were performed using an intra-oral scanner (CEREC Omnicam, Sirona). Immediately after the impressions were made, the subjects' attitudes, preferences and perceptions towards impression techniques were evaluated using a standardized questionnaire. The perceived source of stress was evaluated using the State-Trait Anxiety Scale. Processing steps of the impression techniques (tray selection, working time etc.) were recorded in seconds. Statistical analyses were performed with the Wilcoxon Rank test, and p < 0.05 was considered significant. There were significant differences among the groups (p < 0.05) in terms of total working time and processing steps. Patients stated that digital impressions were more comfortable than conventional techniques. Digital impressions resulted in a more time-efficient technique than conventional impressions. Patients preferred the digital impression technique rather than conventional techniques.

Evaluation of the marginal fit of metal copings fabricated on three different marginal designs using conventional and accelerated casting techniques: an in vitro study.

PubMed

Vaidya, Sharad; Parkash, Hari; Bhargava, Akshay; Gupta, Sharad

2014-01-01

Abundant resources and techniques have been used for complete coverage crown fabrication. Conventional investing and casting procedures for phosphate-bonded investments require a 2- to 4-h procedure before completion. Accelerated casting techniques have been used, but may not result in castings with matching marginal accuracy. The study measured the marginal gap and determined the clinical acceptability of single cast copings invested in a phosphate-bonded investment with the use of conventional and accelerated methods. One hundred and twenty cast coping samples were fabricated using conventional and accelerated methods, with three finish lines: Chamfer, shoulder and shoulder with bevel. Sixty copings were prepared with each technique. Each coping was examined with a stereomicroscope at four predetermined sites and measurements of marginal gaps were documented for each. A master chart was prepared for all the data and was analyzed using Statistical Package for the Social Sciences version. Evidence of marginal gap was then evaluated by t-test. Analysis of variance and Post-hoc analysis were used to compare two groups as well as to make comparisons between three subgroups . Measurements recorded showed no statistically significant difference between conventional and accelerated groups. Among the three marginal designs studied, shoulder with bevel showed the best marginal fit with conventional as well as accelerated casting techniques. Accelerated casting technique could be a vital alternative to the time-consuming conventional casting technique. The marginal fit between the two casting techniques showed no statistical difference.

Laser welding of vas deferens in rodents: initial experience with fluid solders.

PubMed

Trickett, R I; Wang, D; Maitz, P; Lanzetta, M; Owen, E R

1998-01-01

This study evaluates the use of sutureless laser welding for vasovasostomy. In 14 rodents, the left vas deferens underwent vasovasostomy using an albumin-based solder applied to the adventitia of the vas deferens. The solder contained the dye, indocyanine green, to allow selective absorption and denaturation by a fiber-coupled 800-nm diode laser. The right vas deferens served as a control, receiving conventional layered microsurgical repair. We used a removable 4/0 nylon stent and microclamps to appose the vas deferens during repair, with no need for stay sutures. The mean time to perform laser solder repair (23.5 min) and conventional repair (23.3 min) were not significantly different (P=0.91). However, examination after 8 weeks showed that granuloma formation (G) and patency (P) rates for the conventional suture technique (G, 14%; P, 93%) were significantly better than observed for the laser solder technique (G, 57%; P, 50%).

Indocyanine green videoangiography methodological variations: review.

PubMed

Simal-Julián, Juan A; Miranda-Lloret, Pablo; Evangelista-Zamora, Rocio; Sanromán-Álvarez, Pablo; Pérez de San Román, Laila; Pérez-Borredá, Pedro; Beltrán-Giner, Andrés; Botella-Asunción, Carlos

2015-01-01

Indocyanine green videoangiography (ICGVA) procedures have become widespread within the spectrum of microsurgical techniques for neurovascular pathologies. We have conducted a review to identify and assess the impact of all of the methodological variations of conventional ICGVA applied in the field of neurovascular pathology that have been published to date in the English literature. A total of 18 studies were included in this review, identifying four primary methodological variants compared to conventional ICGVA: techniques based on the transient occlusion, intra-arterial ICG administration via catheters, use of endoscope system with a filter to collect florescence of ICG, and quantitative fluorescence analysis. These variants offer some possibilities for resolving the limitations of the conventional technique (first, the vascular structure to be analyzed must be exposed and second, vascular filling with ICG follows an additive pattern) and allow qualitatively superior information to be obtained during surgery. Advantages and disadvantages of each procedure are discussed. More case studies with a greater number of patients are needed to compare the different procedures with their gold standard, in order to establish these results consistently.

Optimization of white matter tractography for pre-surgical planning and image-guided surgery.

PubMed

Arfanakis, Konstantinos; Gui, Minzhi; Lazar, Mariana

2006-01-01

Accurate localization of white matter fiber tracts in relation to brain tumors is a goal of critical importance to the neurosurgical community. White matter fiber tractography by means of diffusion tensor magnetic resonance imaging (DTI) is the only non-invasive method that can provide estimates of brain connectivity. However, conventional tractography methods are based on data acquisition techniques that suffer from image distortions and artifacts. Thus, a large percentage of white matter fiber bundles are distorted, and/or terminated early, while others are completely undetected. This severely limits the potential of fiber tractography in pre-surgical planning and image-guided surgery. In contrast, Turboprop-DTI is a technique that provides images with significantly fewer distortions and artifacts than conventional DTI data acquisition methods. The purpose of this study was to evaluate fiber tracking results obtained from Turboprop-DTI data. It was demonstrated that Turboprop may be a more appropriate DTI data acquisition technique for tracing white matter fibers than conventional DTI methods, especially in applications such as pre-surgical planning and image-guided surgery.

Comparative Evaluation of Conventional and Accelerated Castings on Marginal Fit and Surface Roughness.

PubMed

Jadhav, Vivek Dattatray; Motwani, Bhagwan K; Shinde, Jitendra; Adhapure, Prasad

2017-01-01

The aim of this study was to evaluate the marginal fit and surface roughness of complete cast crowns made by a conventional and an accelerated casting technique. This study was divided into three parts. In Part I, the marginal fit of full metal crowns made by both casting techniques in the vertical direction was checked, in Part II, the fit of sectional metal crowns in the horizontal direction made by both casting techniques was checked, and in Part III, the surface roughness of disc-shaped metal plate specimens made by both casting techniques was checked. A conventional technique was compared with an accelerated technique. In Part I of the study, the marginal fit of the full metal crowns as well as in Part II, the horizontal fit of sectional metal crowns made by both casting techniques was determined, and in Part III, the surface roughness of castings made with the same techniques was compared. The results of the t -test and independent sample test do not indicate statistically significant differences in the marginal discrepancy detected between the two casting techniques. For the marginal discrepancy and surface roughness, crowns fabricated with the accelerated technique were significantly different from those fabricated with the conventional technique. Accelerated casting technique showed quite satisfactory results, but the conventional technique was superior in terms of marginal fit and surface roughness.

Simple adaptive sparse representation based classification schemes for EEG based brain-computer interface applications.

PubMed

Shin, Younghak; Lee, Seungchan; Ahn, Minkyu; Cho, Hohyun; Jun, Sung Chan; Lee, Heung-No

2015-11-01

One of the main problems related to electroencephalogram (EEG) based brain-computer interface (BCI) systems is the non-stationarity of the underlying EEG signals. This results in the deterioration of the classification performance during experimental sessions. Therefore, adaptive classification techniques are required for EEG based BCI applications. In this paper, we propose simple adaptive sparse representation based classification (SRC) schemes. Supervised and unsupervised dictionary update techniques for new test data and a dictionary modification method by using the incoherence measure of the training data are investigated. The proposed methods are very simple and additional computation for the re-training of the classifier is not needed. The proposed adaptive SRC schemes are evaluated using two BCI experimental datasets. The proposed methods are assessed by comparing classification results with the conventional SRC and other adaptive classification methods. On the basis of the results, we find that the proposed adaptive schemes show relatively improved classification accuracy as compared to conventional methods without requiring additional computation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Polymerization shrinkage of a dental resin composite determined by a fiber optic Fizeau interferometer

NASA Astrophysics Data System (ADS)

Arenas, Gustavo; Noriega, Sergio; Vallo, Claudia; Duchowicz, Ricardo

2007-03-01

A fiber optic sensing method based on a Fizeau-type interferometric scheme was employed for monitoring linear polymerization shrinkage in dental restoratives. This technique offers several advantages over the conventional methods of measuring polymerization contraction. This simple, compact, non-invasive and self-calibrating system competes with both conventional and other high-resolution bulk interferometric techniques. In this work, an analysis of the quality of interference signal and fringes visibility was performed in order to characterize their resolution and application range. The measurements of percent linear contraction as a function of the sample thickness were carried out in this study on two dental composites: Filtek P60 (3M ESPE) Posterior Restorer and Filtek Z250 (3M ESPE) Universal Restorer. The results were discussed with respect to others obtained employing alternative techniques.

Phase contrast imaging of buccal mucosa tissues-Feasibility study

NASA Astrophysics Data System (ADS)

Fatima, A.; Tripathi, S.; Shripathi, T.; Kulkarni, V. K.; Banda, N. R.; Agrawal, A. K.; Sarkar, P. S.; Kashyap, Y.; Sinha, A.

2015-06-01

Phase Contrast Imaging (PCI) technique has been used to interpret physical parameters obtained from the image taken on the normal buccal mucosa tissue extracted from cheek of a patient. The advantages of this method over the conventional imaging techniques are discussed. PCI technique uses the X-ray phase shift at the edges differentiated by very minute density differences and the edge enhanced high contrast images reveal details of soft tissues. The contrast in the images produced is related to changes in the X-ray refractive index of the tissues resulting in higher clarity compared with conventional absorption based X-ray imaging. The results show that this type of imaging has better ability to visualize microstructures of biological soft tissues with good contrast, which can lead to the diagnosis of lesions at an early stage of the diseases.

A comparison of spectral decorrelation techniques and performance evaluation metrics for a wavelet-based, multispectral data compression algorithm

NASA Technical Reports Server (NTRS)

Matic, Roy M.; Mosley, Judith I.

1994-01-01

Future space-based, remote sensing systems will have data transmission requirements that exceed available downlinks necessitating the use of lossy compression techniques for multispectral data. In this paper, we describe several algorithms for lossy compression of multispectral data which combine spectral decorrelation techniques with an adaptive, wavelet-based, image compression algorithm to exploit both spectral and spatial correlation. We compare the performance of several different spectral decorrelation techniques including wavelet transformation in the spectral dimension. The performance of each technique is evaluated at compression ratios ranging from 4:1 to 16:1. Performance measures used are visual examination, conventional distortion measures, and multispectral classification results. We also introduce a family of distortion metrics that are designed to quantify and predict the effect of compression artifacts on multi spectral classification of the reconstructed data.

Unlocking hidden genomic sequence

PubMed Central

Keith, Jonathan M.; Cochran, Duncan A. E.; Lala, Gita H.; Adams, Peter; Bryant, Darryn; Mitchelson, Keith R.

2004-01-01

Despite the success of conventional Sanger sequencing, significant regions of many genomes still present major obstacles to sequencing. Here we propose a novel approach with the potential to alleviate a wide range of sequencing difficulties. The technique involves extracting target DNA sequence from variants generated by introduction of random mutations. The introduction of mutations does not destroy original sequence information, but distributes it amongst multiple variants. Some of these variants lack problematic features of the target and are more amenable to conventional sequencing. The technique has been successfully demonstrated with mutation levels up to an average 18% base substitution and has been used to read previously intractable poly(A), AT-rich and GC-rich motifs. PMID:14973330

Visualizing molecular diffusion through passive permeability barriers in cells: conventional and novel approaches.

PubMed

Lin, Yu-Chun; Phua, Siew Cheng; Lin, Benjamin; Inoue, Takanari

2013-08-01

Diffusion barriers are universal solutions for cells to achieve distinct organizations, compositions, and activities within a limited space. The influence of diffusion barriers on the spatiotemporal dynamics of signaling molecules often determines cellular physiology and functions. Over the years, the passive permeability barriers in various subcellular locales have been characterized using elaborate analytical techniques. In this review, we will summarize the current state of knowledge on the various passive permeability barriers present in mammalian cells. We will conclude with a description of several conventional techniques and one new approach based on chemically inducible diffusion trap (CIDT) for probing permeable barriers. Copyright © 2013 Elsevier Ltd. All rights reserved.

NQR: From imaging to explosives and drugs detection

NASA Astrophysics Data System (ADS)

Osán, Tristán M.; Cerioni, Lucas M. C.; Forguez, José; Ollé, Juan M.; Pusiol, Daniel J.

2007-02-01

The main aim of this work is to present an overview of the nuclear quadrupole resonance (NQR) spectroscopy capabilities for solid state imaging and detection of illegal substances, such as explosives and drugs. We briefly discuss the evolution of different NQR imaging techniques, in particular those involving spatial encoding which permit conservation of spectroscopic information. It has been shown that plastic explosives and other forbidden substances cannot be easily detected by means of conventional inspection techniques, such as those based on conventional X-ray technology. For this kind of applications, the experimental results show that the information inferred from NQR spectroscopy provides excellent means to perform volumetric and surface detection of dangerous explosive and drug compounds.

Web-Based Interactive 3D Visualization as a Tool for Improved Anatomy Learning

ERIC Educational Resources Information Center

Petersson, Helge; Sinkvist, David; Wang, Chunliang; Smedby, Orjan

2009-01-01

Despite a long tradition, conventional anatomy education based on dissection is declining. This study tested a new virtual reality (VR) technique for anatomy learning based on virtual contrast injection. The aim was to assess whether students value this new three-dimensional (3D) visualization method as a learning tool and what value they gain…

A Hybrid Neural Network Model for Sales Forecasting Based on ARIMA and Search Popularity of Article Titles.

PubMed

Omar, Hani; Hoang, Van Hai; Liu, Duen-Ren

2016-01-01

Enhancing sales and operations planning through forecasting analysis and business intelligence is demanded in many industries and enterprises. Publishing industries usually pick attractive titles and headlines for their stories to increase sales, since popular article titles and headlines can attract readers to buy magazines. In this paper, information retrieval techniques are adopted to extract words from article titles. The popularity measures of article titles are then analyzed by using the search indexes obtained from Google search engine. Backpropagation Neural Networks (BPNNs) have successfully been used to develop prediction models for sales forecasting. In this study, we propose a novel hybrid neural network model for sales forecasting based on the prediction result of time series forecasting and the popularity of article titles. The proposed model uses the historical sales data, popularity of article titles, and the prediction result of a time series, Autoregressive Integrated Moving Average (ARIMA) forecasting method to learn a BPNN-based forecasting model. Our proposed forecasting model is experimentally evaluated by comparing with conventional sales prediction techniques. The experimental result shows that our proposed forecasting method outperforms conventional techniques which do not consider the popularity of title words.

A Hybrid Neural Network Model for Sales Forecasting Based on ARIMA and Search Popularity of Article Titles

PubMed Central

Omar, Hani; Hoang, Van Hai; Liu, Duen-Ren

2016-01-01

Enhancing sales and operations planning through forecasting analysis and business intelligence is demanded in many industries and enterprises. Publishing industries usually pick attractive titles and headlines for their stories to increase sales, since popular article titles and headlines can attract readers to buy magazines. In this paper, information retrieval techniques are adopted to extract words from article titles. The popularity measures of article titles are then analyzed by using the search indexes obtained from Google search engine. Backpropagation Neural Networks (BPNNs) have successfully been used to develop prediction models for sales forecasting. In this study, we propose a novel hybrid neural network model for sales forecasting based on the prediction result of time series forecasting and the popularity of article titles. The proposed model uses the historical sales data, popularity of article titles, and the prediction result of a time series, Autoregressive Integrated Moving Average (ARIMA) forecasting method to learn a BPNN-based forecasting model. Our proposed forecasting model is experimentally evaluated by comparing with conventional sales prediction techniques. The experimental result shows that our proposed forecasting method outperforms conventional techniques which do not consider the popularity of title words. PMID:27313605

A discrete wavelet based feature extraction and hybrid classification technique for microarray data analysis.

PubMed

Bennet, Jaison; Ganaprakasam, Chilambuchelvan Arul; Arputharaj, Kannan

2014-01-01

Cancer classification by doctors and radiologists was based on morphological and clinical features and had limited diagnostic ability in olden days. The recent arrival of DNA microarray technology has led to the concurrent monitoring of thousands of gene expressions in a single chip which stimulates the progress in cancer classification. In this paper, we have proposed a hybrid approach for microarray data classification based on nearest neighbor (KNN), naive Bayes, and support vector machine (SVM). Feature selection prior to classification plays a vital role and a feature selection technique which combines discrete wavelet transform (DWT) and moving window technique (MWT) is used. The performance of the proposed method is compared with the conventional classifiers like support vector machine, nearest neighbor, and naive Bayes. Experiments have been conducted on both real and benchmark datasets and the results indicate that the ensemble approach produces higher classification accuracy than conventional classifiers. This paper serves as an automated system for the classification of cancer and can be applied by doctors in real cases which serve as a boon to the medical community. This work further reduces the misclassification of cancers which is highly not allowed in cancer detection.

Estimating propagation velocity through a surface acoustic wave sensor

DOEpatents

Xu, Wenyuan; Huizinga, John S.

2010-03-16

Techniques are described for estimating the propagation velocity through a surface acoustic wave sensor. In particular, techniques which measure and exploit a proper segment of phase frequency response of the surface acoustic wave sensor are described for use as a basis of bacterial detection by the sensor. As described, use of velocity estimation based on a proper segment of phase frequency response has advantages over conventional techniques that use phase shift as the basis for detection.

Instrumental color control for metallic coatings

NASA Astrophysics Data System (ADS)

Chou, W.; Han, Bing; Cui, Guihua; Rigg, Bryan; Luo, Ming R.

2002-06-01

This paper describes work investigating a suitable color quality control method for metallic coatings. A set of psychological experiments was carried out based upon 50 pairs of samples. The results were used to test the performance of various color difference formulae. Different techniques were developed by optimising the weights and/or the lightness parametric factors of colour differences calculated from the four measuring angles. The results show that the new techniques give a significant improvement compared to conventional techniques.

Comparison of digital and conventional impression techniques: evaluation of patients’ perception, treatment comfort, effectiveness and clinical outcomes

PubMed Central

2014-01-01

Background The purpose of this study was to compare two impression techniques from the perspective of patient preferences and treatment comfort. Methods Twenty-four (12 male, 12 female) subjects who had no previous experience with either conventional or digital impression participated in this study. Conventional impressions of maxillary and mandibular dental arches were taken with a polyether impression material (Impregum, 3 M ESPE), and bite registrations were made with polysiloxane bite registration material (Futar D, Kettenbach). Two weeks later, digital impressions and bite scans were performed using an intra-oral scanner (CEREC Omnicam, Sirona). Immediately after the impressions were made, the subjects’ attitudes, preferences and perceptions towards impression techniques were evaluated using a standardized questionnaire. The perceived source of stress was evaluated using the State-Trait Anxiety Scale. Processing steps of the impression techniques (tray selection, working time etc.) were recorded in seconds. Statistical analyses were performed with the Wilcoxon Rank test, and p < 0.05 was considered significant. Results There were significant differences among the groups (p < 0.05) in terms of total working time and processing steps. Patients stated that digital impressions were more comfortable than conventional techniques. Conclusions Digital impressions resulted in a more time-efficient technique than conventional impressions. Patients preferred the digital impression technique rather than conventional techniques. PMID:24479892

An evaluation of student and clinician perception of digital and conventional implant impressions.

PubMed

Lee, Sang J; Macarthur, Robert X; Gallucci, German O

2013-11-01

The accuracy and efficiency of digital implant impressions should match conventional impressions. Comparisons should be made with clinically relevant data. The purpose of this study was to evaluate the difficulty level and operator's perception between dental students and experienced clinicians when making digital and conventional implant impressions. Thirty experienced dental professionals and 30 second-year dental students made conventional and digital impressions of a single implant model. A visual analog scale (VAS) and multiple-choice questionnaires were used to assess the participant's perception of difficulty, preference, and effectiveness. Wilcoxon signed-rank test within the groups and Wilcoxon rank-sum test between the groups were used for statistical analysis (α=.05). On a 0 to 100 VAS, the student group scored a mean difficulty level of 43.1 (±18.5) for the conventional impression technique and 30.6 (±17.6) for the digital impression technique (P=.006). The clinician group scored a mean (standard deviation) difficulty level of 30.9 (±19.6) for conventional impressions and 36.5 (±20.6) for digital impressions (P=.280). Comparison between groups showed a mean difficulty level with the conventional impression technique significantly higher in the student group (P=.030). The digital impression was not significantly different between the groups (P=.228). Sixty percent of the students preferred the digital impression and 7% the conventional impression; 33% expressed no preference. In the clinician group, 33% preferred the digital impression and 37% the conventional impression; 30% had no preference. Seventy-seven percent of the student group felt most effective with digital impressions, 10% with conventional impressions, and 13% with either technique, whereas 40% of the clinician group chose the digital impression as the most effective technique, 53% the conventional impression, and 7% either technique. The conventional impression was more difficult to perform for the student group than the clinician group; however, the difficulty level of the digital impression was the same in both groups. It was also determined that the student group preferred the digital impression as the most efficient impression technique, and the clinician group had an even distribution in the choice of preferred and efficient impression techniques. Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Development of fuzzy air quality index using soft computing approach.

PubMed

Mandal, T; Gorai, A K; Pathak, G

2012-10-01

Proper assessment of air quality status in an atmosphere based on limited observations is an essential task for meeting the goals of environmental management. A number of classification methods are available for estimating the changing status of air quality. However, a discrepancy frequently arises from the quality criteria of air employed and vagueness or fuzziness embedded in the decision making output values. Owing to inherent imprecision, difficulties always exist in some conventional methodologies like air quality index when describing integrated air quality conditions with respect to various pollutants parameters and time of exposure. In recent years, the fuzzy logic-based methods have demonstrated to be appropriated to address uncertainty and subjectivity in environmental issues. In the present study, a methodology based on fuzzy inference systems (FIS) to assess air quality is proposed. This paper presents a comparative study to assess status of air quality using fuzzy logic technique and that of conventional technique. The findings clearly indicate that the FIS may successfully harmonize inherent discrepancies and interpret complex conditions.

Characteristics of low polymerization shrinkage flowable resin composites in newly-developed cavity base materials for bulk filling technique.

PubMed

Nitta, Keiko; Nomoto, Rie; Tsubota, Yuji; Tsuchikawa, Masuji; Hayakawa, Tohru

2017-11-29

The purpose of this study was to evaluate polymerization shrinkage and other physical properties of newly-developed cavity base materials for bulk filling technique, with the brand name BULK BASE (BBS). Polymerization shrinkage was measured according to ISO/FDIS 17304. BBS showed the significantly lowest polymerization shrinkage and significantly higher depth of cure than conventional flowable resin composites (p<0.05). The Knoop hardness, flexural strength and elastic modulus of that were significantly lower than conventional flowable resin composites (p<0.05). BBS had the significantly greatest filler content (p<0.05). SEM images of the surface showed failure of fillers. The lowest polymerization shrinkage was due to the incorporation of a new type of low shrinkage monomer, which has urethane moieties. There were no clear correlations between inorganic filler contents and polymerization shrinkage, flexural strength and elastic modulus. In conclusion, the low polymerization shrinkage of BBS will be useful for cavity treatment in dental clinics.

Cost-effectiveness of liquid-based cytology with or without hybrid-capture II HPV test compared with conventional Pap smears: a study by the French Society of Clinical Cytology.

PubMed

Cochand-Priollet, Béatrix; Cartier, Isabelle; de Cremoux, Patricia; Le Galès, Catherine; Ziol, Marianne; Molinié, Vincent; Petitjean, Alain; Dosda, Anne; Merea, Estelle; Biaggi, Annonciade; Gouget, Isabelle; Arkwright, Sylviane; Vacher-Lavenu, Marie-Cécile; Vielh, Philippe; Coste, Joël

2005-11-01

Many articles concerning conventional Pap smears, ThinPrep liquid-based cytology (LBC) and Hybrid-Capture II HPV test (HC II) have been published. This study, carried out by the French Society of Clinical Cytology, may be conspicuous for several reasons: it was financially independent; it compared the efficiency of the conventional Pap smear and LBC, of the conventional Pap smear and HC II, and included an economic study based on real costs; for all the women, a "gold standard" reference method, colposcopy, was available and biopsies were performed whenever a lesion was detected; The conventional Pap smear, the LBC (split-sample technique), the colposcopy, and the biopsies were done at the same time. This study included 2,585 women shared into two groups: a group A of a high-risk population, a group B of a screening population. The statistical analysis of the results showed that conventional Pap smears consistently had superior or equivalent sensitivity and specificity than LBC for the lesions at threshold CIN-I (Cervical Intraepithelial Neoplasia) or CIN-II or higher. It underlined the low specificity of the HC II. Finally, the LBC mean cost was never covered by the Social Security tariff.

Review of Quantitative Ultrasound: Envelope Statistics and Backscatter Coefficient Imaging and Contributions to Diagnostic Ultrasound.

PubMed

Oelze, Michael L; Mamou, Jonathan

2016-02-01

Conventional medical imaging technologies, including ultrasound, have continued to improve over the years. For example, in oncology, medical imaging is characterized by high sensitivity, i.e., the ability to detect anomalous tissue features, but the ability to classify these tissue features from images often lacks specificity. As a result, a large number of biopsies of tissues with suspicious image findings are performed each year with a vast majority of these biopsies resulting in a negative finding. To improve specificity of cancer imaging, quantitative imaging techniques can play an important role. Conventional ultrasound B-mode imaging is mainly qualitative in nature. However, quantitative ultrasound (QUS) imaging can provide specific numbers related to tissue features that can increase the specificity of image findings leading to improvements in diagnostic ultrasound. QUS imaging can encompass a wide variety of techniques including spectral-based parameterization, elastography, shear wave imaging, flow estimation, and envelope statistics. Currently, spectral-based parameterization and envelope statistics are not available on most conventional clinical ultrasound machines. However, in recent years, QUS techniques involving spectral-based parameterization and envelope statistics have demonstrated success in many applications, providing additional diagnostic capabilities. Spectral-based techniques include the estimation of the backscatter coefficient (BSC), estimation of attenuation, and estimation of scatterer properties such as the correlation length associated with an effective scatterer diameter (ESD) and the effective acoustic concentration (EAC) of scatterers. Envelope statistics include the estimation of the number density of scatterers and quantification of coherent to incoherent signals produced from the tissue. Challenges for clinical application include correctly accounting for attenuation effects and transmission losses and implementation of QUS on clinical devices. Successful clinical and preclinical applications demonstrating the ability of QUS to improve medical diagnostics include characterization of the myocardium during the cardiac cycle, cancer detection, classification of solid tumors and lymph nodes, detection and quantification of fatty liver disease, and monitoring and assessment of therapy.

Intracorporeal hybrid single port vs conventional laparoscopic appendectomy in children.

PubMed

Karam, Paul Anthony; Hiuser, Amy; Magnuson, David; Seifarth, Federico Gian Filippo

2016-12-20

Transumbilical laparoscopic assisted appendectomy combines laparoscopic single port dissection with open appendectomy after exteriorization of the appendix through the port site. Compared to the conventional three-port approach, this technique provides an alternative with excellent cosmetic outcome. We developed a safe and effective technique to perform an intracorporeal single port appendectomy, using the same laparoscope employed in the extracorporeal procedure. Retrospective review of 71 consecutively performed intracorporeal single port appendectomies and 30 conventional three-port appendectomies in children 6 to 17 years of age. A straight 10-mm Storz telescope with inbuilt 6 mm working channel is used to dissect the appendix, combined with one port-less 2.3 mm percutaneous grasper. Polymer WECK® hem-o-lock® clips are applied to seal the base of the appendix and the appendiceal vessels. No intraoperative complications were reported with the hybrid intracorporeal single port appendectomy or three-port appendectomy. There were two post-operative complications in the group treated with the single port hybrid technique: one intra-abdominal abscess and one surgical site infection. Groups did not differ in age, weight, and types of appendicitis. Operative times were shorter for the hybrid technique (70 vs 79 minutes) but did not differ significantly (P=0.19). This modified technique to a previously described single port extracorporeal appendectomy is easy to master and implement. It provides exposure similar to a three-port laparoscopic appendectomy, while maintaining virtually scarless results and potentially reduces the risk for surgical site infections compared to the extracorporeal technique.

Leak Detection and Location of Water Pipes Using Vibration Sensors and Modified ML Prefilter.

PubMed

Choi, Jihoon; Shin, Joonho; Song, Choonggeun; Han, Suyong; Park, Doo Il

2017-09-13

This paper proposes a new leak detection and location method based on vibration sensors and generalised cross-correlation techniques. Considering the estimation errors of the power spectral densities (PSDs) and the cross-spectral density (CSD), the proposed method employs a modified maximum-likelihood (ML) prefilter with a regularisation factor. We derive a theoretical variance of the time difference estimation error through summation in the discrete-frequency domain, and find the optimal regularisation factor that minimises the theoretical variance in practical water pipe channels. The proposed method is compared with conventional correlation-based techniques via numerical simulations using a water pipe channel model, and it is shown through field measurement that the proposed modified ML prefilter outperforms conventional prefilters for the generalised cross-correlation. In addition, we provide a formula to calculate the leak location using the time difference estimate when different types of pipes are connected.

Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques

PubMed Central

Parkash, Om; Hanim Shueb, Rafidah

2015-01-01

Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed. PMID:26492265

Leak Detection and Location of Water Pipes Using Vibration Sensors and Modified ML Prefilter

PubMed Central

Shin, Joonho; Song, Choonggeun; Han, Suyong; Park, Doo Il

2017-01-01

This paper proposes a new leak detection and location method based on vibration sensors and generalised cross-correlation techniques. Considering the estimation errors of the power spectral densities (PSDs) and the cross-spectral density (CSD), the proposed method employs a modified maximum-likelihood (ML) prefilter with a regularisation factor. We derive a theoretical variance of the time difference estimation error through summation in the discrete-frequency domain, and find the optimal regularisation factor that minimises the theoretical variance in practical water pipe channels. The proposed method is compared with conventional correlation-based techniques via numerical simulations using a water pipe channel model, and it is shown through field measurement that the proposed modified ML prefilter outperforms conventional prefilters for the generalised cross-correlation. In addition, we provide a formula to calculate the leak location using the time difference estimate when different types of pipes are connected. PMID:28902154

Domestic and Industrial Water Disinfection Using Boron-Doped Diamond Electrodes

NASA Astrophysics Data System (ADS)

Rychen, Philippe; Provent, Christophe; Pupunat, Laurent; Hermant, Nicolas

This chapter first describes main properties and manufacturing process (production using HF-CVD, quality-control measurements, etc.) of diamond electrodes and more specifically boron-doped diamond (BDD) electrodes. Their exceptional properties make such electrodes particularly suited for many disinfection applications as thanks to their wide working potential window and their high anodic potential, they allow generating a mixture of powerful oxidizing species mainly based on active oxygen and peroxides. Such mixture of disinfecting agents is far more efficient than conventional chemical or physical known techniques. Their efficiency was tested against numerous microorganisms and then proved to be greater than conventional methods. All bacteria and viruses tested up to date were inactivated 3-5 times faster with a treatment based on with BDD electrodes and the DiaCellⓇ technology than with other techniques. Several applications, either industrial or private (wellness and home use), are discussed with a focus on the dedicated products and the main technology advantages.

microRNA biosensors: Opportunities and challenges among conventional and commercially available techniques.

PubMed

Kilic, Tugba; Erdem, Arzum; Ozsoz, Mehmet; Carrara, Sandro

2018-01-15

As being the most extensively studied, non-coding, evolutionary conserved, post-transcriptional gene regulators of genome, microRNAs (miRNAs) have taken great attention among various disciplines due to their important roles in biological processes and link with cancer. Due to their diagnostic value, there have been many conventional methods used in detection of miRNAs including northern blotting, quantitative real time PCR (qRT-PCR) and microarray technology besides novel techniques based on various nanotechnology approaches and molecular biology tools including miRNA biosensors. The aim of this review is to explain the importance of miRNAs in biomedical field with an emphasis on early cancer diagnosis by overviewing both research based and commercially available miRNA detection methods in the last decade considering their strengths and weakness with an emphasis on miRNA biosensors. Copyright © 2017 Elsevier B.V. All rights reserved.

Theory, simulation and experiments for precise deflection control of radiotherapy electron beams.

PubMed

Figueroa, R; Leiva, J; Moncada, R; Rojas, L; Santibáñez, M; Valente, M; Velásquez, J; Young, H; Zelada, G; Yáñez, R; Guillen, Y

2018-03-08

Conventional radiotherapy is mainly applied by linear accelerators. Although linear accelerators provide dual (electron/photon) radiation beam modalities, both of them are intrinsically produced by a megavoltage electron current. Modern radiotherapy treatment techniques are based on suitable devices inserted or attached to conventional linear accelerators. Thus, precise control of delivered beam becomes a main key issue. This work presents an integral description of electron beam deflection control as required for novel radiotherapy technique based on convergent photon beam production. Theoretical and Monte Carlo approaches were initially used for designing and optimizing device´s components. Then, dedicated instrumentation was developed for experimental verification of electron beam deflection due to the designed magnets. Both Monte Carlo simulations and experimental results support the reliability of electrodynamics models used to predict megavoltage electron beam control. Copyright © 2018 Elsevier Ltd. All rights reserved.

Validation of highly reliable, real-time knowledge-based systems

NASA Technical Reports Server (NTRS)

Johnson, Sally C.

1988-01-01

Knowledge-based systems have the potential to greatly increase the capabilities of future aircraft and spacecraft and to significantly reduce support manpower needed for the space station and other space missions. However, a credible validation methodology must be developed before knowledge-based systems can be used for life- or mission-critical applications. Experience with conventional software has shown that the use of good software engineering techniques and static analysis tools can greatly reduce the time needed for testing and simulation of a system. Since exhaustive testing is infeasible, reliability must be built into the software during the design and implementation phases. Unfortunately, many of the software engineering techniques and tools used for conventional software are of little use in the development of knowledge-based systems. Therefore, research at Langley is focused on developing a set of guidelines, methods, and prototype validation tools for building highly reliable, knowledge-based systems. The use of a comprehensive methodology for building highly reliable, knowledge-based systems should significantly decrease the time needed for testing and simulation. A proven record of delivering reliable systems at the beginning of the highly visible testing and simulation phases is crucial to the acceptance of knowledge-based systems in critical applications.

Comparative Evaluation of Conventional and Accelerated Castings on Marginal Fit and Surface Roughness

PubMed Central

Jadhav, Vivek Dattatray; Motwani, Bhagwan K.; Shinde, Jitendra; Adhapure, Prasad

2017-01-01

Aims: The aim of this study was to evaluate the marginal fit and surface roughness of complete cast crowns made by a conventional and an accelerated casting technique. Settings and Design: This study was divided into three parts. In Part I, the marginal fit of full metal crowns made by both casting techniques in the vertical direction was checked, in Part II, the fit of sectional metal crowns in the horizontal direction made by both casting techniques was checked, and in Part III, the surface roughness of disc-shaped metal plate specimens made by both casting techniques was checked. Materials and Methods: A conventional technique was compared with an accelerated technique. In Part I of the study, the marginal fit of the full metal crowns as well as in Part II, the horizontal fit of sectional metal crowns made by both casting techniques was determined, and in Part III, the surface roughness of castings made with the same techniques was compared. Statistical Analysis Used: The results of the t-test and independent sample test do not indicate statistically significant differences in the marginal discrepancy detected between the two casting techniques. Results: For the marginal discrepancy and surface roughness, crowns fabricated with the accelerated technique were significantly different from those fabricated with the conventional technique. Conclusions: Accelerated casting technique showed quite satisfactory results, but the conventional technique was superior in terms of marginal fit and surface roughness. PMID:29042726

Comparison of the fit of cast gold crowns fabricated from the digital and the conventional impression techniques

PubMed Central

Jeon, Young-Chan; Jeong, Chang-Mo

2017-01-01

PURPOSE The purpose of this study was to compare the fit of cast gold crowns fabricated from the conventional and the digital impression technique. MATERIALS AND METHODS Artificial tooth in a master model and abutment teeth in ten patients were restored with cast gold crowns fabricated from the digital and the conventional impression technique. The forty silicone replicas were cut in three sections; each section was evaluated in nine points. The measurement was carried out by using a measuring microscope and I-Soultion. Data from the silicone replica were analyzed and all tests were performed with α-level of 0.05. RESULTS 1. The average gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. 2. In marginal and internal axial gap of cast gold crowns, no statistical differences were found between the two impression techniques. 3. The internal occlusal gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. CONCLUSION Both prostheses presented clinically acceptable results with comparing the fit. The prostheses fabricated from the digital impression technique showed more gaps, in respect of occlusal surface. PMID:28243386

A simple, less invasive stripper micropipetter-based technique for day 3 embryo biopsy.

PubMed

Cedillo, Luciano; Ocampo-Bárcenas, Azucena; Maldonado, Israel; Valdez-Morales, Francisco J; Camargo, Felipe; López-Bayghen, Esther

2016-01-01

Preimplantation genetic screening (PGS) is an important procedure for in vitro fertilization (IVF). A key step of PGS, blastomere removal, is abundant with many technical issues. The aim of this study was to compare a more simple procedure based on the Stipper Micropipetter, named S-biopsy, to the conventional aspiration method. On Day 3, 368 high-quality embryos (>7 cells on Day3 with <10% fragmentation) were collected from 38 women. For each patient, their embryos were equally separated between the conventional method ( n  = 188) and S-biopsy method ( n  = 180). The conventional method was performed using a standardized protocol. For the S-biopsy method, a laser was used to remove a significantly smaller portion of the zona pellucida. Afterwards, the complete embryo was aspirated with a Stripper Micropipetter, forcing the removal of the blastomere. Selected blastomeres went to PGS using CGH microarrays. Embryo integrity and blastocyst formation were assessed on Day 5. Differences between groups were assessed by either the Mann-Whitney test or Fisher Exact test. Both methods resulted in the removal of only one blastomere. The S-biopsy and the conventional method did not differ in terms of affecting embryo integrity (95.0% vs. 95.7%) or blastocyst formation (72.7% vs. 70.7%). PGS analysis indicated that aneuploidy rate were similar between the two methods (63.1% vs. 65.2%). However, the time required to perform the S-biopsy method (179.2 ± 17.5 s) was significantly shorter (5-fold) than the conventional method. The S-biopsy method is comparable to the conventional method that is used to remove a blastomere for PGS, but requires less time. Furthermore, due to the simplicity of the S-biopsy technique, this method is more ideal for IVF laboratories.

Ultrasonic sensor based defect detection and characterisation of ceramics.

PubMed

Kesharaju, Manasa; Nagarajah, Romesh; Zhang, Tonzhua; Crouch, Ian

2014-01-01

Ceramic tiles, used in body armour systems, are currently inspected visually offline using an X-ray technique that is both time consuming and very expensive. The aim of this research is to develop a methodology to detect, locate and classify various manufacturing defects in Reaction Sintered Silicon Carbide (RSSC) ceramic tiles, using an ultrasonic sensing technique. Defects such as free silicon, un-sintered silicon carbide material and conventional porosity are often difficult to detect using conventional X-radiography. An alternative inspection system was developed to detect defects in ceramic components using an Artificial Neural Network (ANN) based signal processing technique. The inspection methodology proposed focuses on pre-processing of signals, de-noising, wavelet decomposition, feature extraction and post-processing of the signals for classification purposes. This research contributes to developing an on-line inspection system that would be far more cost effective than present methods and, moreover, assist manufacturers in checking the location of high density areas, defects and enable real time quality control, including the implementation of accept/reject criteria. Copyright © 2013 Elsevier B.V. All rights reserved.

Fundamentals and techniques of nonimaging optics research

NASA Astrophysics Data System (ADS)

Winston, R.; Ogallagher, J.

1987-07-01

Nonimaging Optics differs from conventional approaches in its relaxation of unnecessary constraints on energy transport imposed by the traditional methods for optimizing image formation and its use of more broadly based analytical techniques such as phase space representations of energy flow, radiative transfer analysis, thermodynamic arguments, etc. Based on these means, techniques for designing optical elements which approach and in some cases attain the maximum concentration permitted by the Second Law of Thermodynamics were developed. The most widely known of these devices are the family of Compound Parabolic Concentrators (CPC's) and their variants and the so called Flow-Line or trumpet concentrator derived from the geometric vector flux formalism developed under this program. Applications of these and other such ideal or near-ideal devices permits increases of typically a factor of four (though in some cases as much as an order of magnitude) in the concentration above that possible with conventional means. Present efforts can be classed into two main areas: (1) classical geometrical nonimaging optics, and (2) logical extensions of nonimaging concepts to the physical optics domain.

Fundamentals and techniques of nonimaging optics research at the University of Chicago

NASA Astrophysics Data System (ADS)

Winston, R.; Ogallagher, J.

1986-11-01

Nonimaging Optics differs from conventional approaches in its relaxation of unnecessary constraints on energy transport imposed by the traditional methods for optimizing image formation and its use of more broadly based analytical techniques such as phase space representations of energy flow, radiative transfer analysis, thermodynamic arguments, etc. Based on these means, techniques for designing optical elements which approach and in some cases attain the maximum concentration permitted by the Second Law of Thermodynamics were developed. The most widely known of these devices are the family of Compound Parabolic Concentrators (CPC's) and their variants and the so called Flow-Line concentrator derived from the geometric vector flux formalism developed under this program. Applications of these and other such ideal or near-ideal devices permits increases of typically a factor of four (though in some cases as much as an order of magnitude) in the concentration above that possible with conventional means. In the most recent phase, our efforts can be classed into two main areas; (a) ''classical'' geometrical nonimaging optics; and (b) logical extensions of nonimaging concepts to the physical optics domain.

Clinical outcomes of individualized botulinum neurotoxin type A injection techniques in patients with essential blepharospasm.

PubMed

Sung, Youngje; Nam, Sang Min; Lew, Helen

2015-04-01

To assess the clinical outcomes following botulinum neurotoxin type A (BoNT-A) treatment with an individualized injection technique based on the types of spasms and to compare the results of the individualized injection technique with those of the conventional injection technique in the same patients. From November 2011 to July 2013, 77 BoNT-A injections were performed in 38 patients. Eighteen patients were treated with conventional BoNT-A injections before 2011, and 20 patients were referred to our hospital for unsatisfactory results after a conventional injection technique. We classified the patients by spasm-dominant sites: the lateral orbital area, representing the orbital orbicularis-dominant group (ODG); the glabella, representing the corrugator-dominant group (CDG); and the ptosis, representing the palpebral part of the orbicularis-dominant group (PDG). We increased the injection dose into the spasm-dominant sites of the blepharospasm groups. We assessed subjective symptom scores (functional disability score, FDS) after treatment. This study included 38 patients (26 women, 12 men; mean age, 60.6 ± 10.9 years). There were 21 patients in the ODG, 10 patients in the CDG, and 7 patients in the PDG. Mean ages were 59.7 ± 12.6, 59.8 ± 8.5, and 66.8 ± 9.0 years, and mean BoNT-A injection dose was 38.8 ± 11.2, 38.8 ± 11.2, and 38.8 ± 10.8 U in each group, respectively (p = 0.44, 0.82 Kruskal-Wallis test). Mean FDS after injection was 1.7 ± 0.7 in the ODG, 1.4 ± 0.8 in the CDG, and 1.2 ± 0.3 in the PDG. There were significant differences in reading and job scale among the three groups. In a comparison between the conventional and individualized injection techniques, there was a significant improvement in mean FDS and in the reading scale in the PDG with the individualized injection technique. The success rate was 92.1% in the conventional injection group and 94.1% in the individualized injection group. The individualized injection technique of BoNT-A according to the spasm-dominant site is an effective and safe treatment method for essential blepharospasm patients.

Development of silicon grisms and immersion gratings for high-resolution infrared spectroscopy

NASA Astrophysics Data System (ADS)

Ge, Jian; McDavitt, Daniel L.; Bernecker, John L.; Miller, Shane; Ciarlo, Dino R.; Kuzmenko, Paul J.

2002-01-01

We report new results on silicon grism and immersion grating development using photolithography and anisotropic chemical etching techniques, which include process recipe finding, prototype grism fabrication, lab performance evaluation and initial scientific observations. The very high refractive index of silicon (n=3.4) enables much higher dispersion power for silicon-based gratings than conventional gratings, e.g. a silicon immersion grating can offer a factor of 3.4 times the dispersion of a conventional immersion grating. Good transmission in the infrared (IR) allows silicon-based gratings to operate in the broad IR wavelength regions (~1- 10 micrometers and far-IR), which make them attractive for both ground and space-based spectroscopic observations. Coarser gratings can be fabricated with these new techniques rather than conventional techniques, allowing observations at very high dispersion orders for larger simultaneous wavelength coverage. We have found new etching techniques for fabricating high quality silicon grisms with low wavefront distortion, low scattered light and high efficiency. Particularly, a new etching process using tetramethyl ammonium hydroxide (TMAH) is significantly simplifying the fabrication process on large, thick silicon substrates, while providing comparable grating quality to our traditional potassium hydroxide (KOH) process. This technique is being used for fabricating inch size silicon grisms for several IR instruments and is planned to be used for fabricating ~ 4 inch size silicon immersion gratings later. We have obtained complete K band spectra of a total of 6 T Tauri and Ae/Be stars and their close companions at a spectral resolution of R ~ 5000 using a silicon echelle grism with a 5 mm pupil diameter at the Lick 3m telescope. These results represent the first scientific observations conducted by the high-resolution silicon grisms, and demonstrate the extremely high dispersing power of silicon- based gratings. The future of silicon-based grating applications in ground and space-based IR instruments is promising. Silicon immersion gratings will make very high-resolution spectroscopy (R>100,000) feasible with compact instruments for implementation on large telescopes. Silicon grisms will offer an efficient way to implement low-cost medium to high resolution IR spectroscopy (R~ 1000-50000) through the conversion of existing cameras into spectrometers by locating a grism in the instrument's pupil location.

Prioritized retransmission in slotted all-optical packet-switched networks

NASA Astrophysics Data System (ADS)

Ghaffar Pour Rahbar, Akbar; Yang, Oliver

2006-12-01

We consider an all-optical slotted packet-switched network interconnected by a number of bufferless all-optical switches with contention-based operation. One approach to reduce the cost of the expensive contention resolution hardware could be retransmission in which each ingress switch keeps a copy of the transmitted traffic in the electronic buffer and retransmits whenever required. The conventional retransmission technique may need a higher number of retransmissions until traffic passes through the network. This in turn may lead to a retransmission at a higher layer and reduce the network throughput. In this paper, we propose and analyze a simple but effective prioritized retransmission technique in which dropped traffic is prioritized when retransmitted from ingress switches so that the core switch can process them with a higher priority. We present the analysis of both techniques in multifiber network architecture and verify it via simulation to demonstrate that our proposed algorithm can limit the number of retransmissions significantly and can improve TCP throughput better than the conventional retransmission technique.

Fracture behavior of metal-ceramic fixed dental prostheses with frameworks from cast or a newly developed sintered cobalt-chromium alloy.

PubMed

Krug, Klaus-Peter; Knauber, Andreas W; Nothdurft, Frank P

2015-03-01

The aim of this study was to investigate the fracture behavior of metal-ceramic bridges with frameworks from cobalt-chromium-molybdenum (CoCrMo), which are manufactured using conventional casting or a new computer-aided design/computer-aided manufacturing (CAD/CAM) milling and sintering technique. A total of 32 metal-ceramic fixed dental prostheses (FDPs), which are based on a nonprecious metal framework, was produced using a conventional casting process (n = 16) or a new CAD/CAM milling and sintering process (n = 16). Eight unveneered frameworks were manufactured using each of the techniques. After thermal and mechanical aging of half of the restorations, all samples were subjected to a static loading test in a universal testing machine, in which acoustic emission monitoring was performed. Three different critical forces were revealed: the fracture force (F max), the force at the first reduction in force (F decr1), and the force at the critical acoustic event (F acoust1). With the exception of the veneered restorations with cast or sintered metal frameworks without artificial aging, which presented a statistically significant but slightly different F max, no statistically significant differences between cast and CAD/CAM sintered and milled FDPs were detected. Thermal and mechanical loading did not significantly affect the resulting forces. Cast and CAD/CAM milled and sintered metal-ceramic bridges were determined to be comparable with respect to the fracture behavior. FDPs based on CAD/CAM milled and sintered frameworks may be an applicable and less technique-sensitive alternative to frameworks that are based on conventionally cast frameworks.

Maxillary incisors changes during space closure with conventional and skeletal anchorage methods: a systematic review.

PubMed

Jayaratne, Yasas Shri Nalaka; Uribe, Flavio; Janakiraman, Nandakumar

2017-01-01

The objective of this systematic review was to compare the antero-posterior, vertical and angular changes of maxillary incisors with conventional anchorage control techniques and mini-implant based space closure methods. The electronic databases Pubmed, Scopus, ISI Web of knowledge, Cochrane Library and Open Grey were searched for potentially eligible studies using a set of predetermined keywords. Full texts meeting the inclusion criteria as well as their references were manually searched. The primary outcome data (linear, angular, and vertical maxillary incisor changes) and secondary outcome data (overbite changes, soft tissue changes, biomechanical factors, root resorption and treatment duration) were extracted from the selected articles and entered into spreadsheets based on the type of anchorage used. The methodological quality of each study was assessed. Six studies met the inclusion criteria. The amount of incisor retraction was greater with buccally placed mini-implants than conventional anchorage techniques. The incisor retraction with indirect anchorage from palatal mini-implants was less when compared with buccally placed mini-implants. Incisor intrusion occurred with buccal mini-implants, whereas extrusion was seen with conventional anchorage. Limited data on the biomechanical variables or adverse effects such as root resorption were reported in these studies. More RCT's that take in to account relevant biomechanical variables and employ three-dimensional quantification of tooth movements are required to provide information on incisor changes during space closure.

Computer-Based Instruction and Health Professions Education: A Meta-Analysis of Outcomes.

ERIC Educational Resources Information Center

Cohen, Peter A.; Dacanay, Lakshmi S.

1992-01-01

The meta-analytic techniques of G. V. Glass were used to statistically integrate findings from 47 comparative studies on computer-based instruction (CBI) in health professions education. A clear majority of the studies favored CBI over conventional methods of instruction. Results show higher-order applications of computers to be especially…

System Identification of Mistuned Bladed Disks from Traveling Wave Response Measurements

NASA Technical Reports Server (NTRS)

Feiner, D. M.; Griffin, J. H.; Jones, K. W.; Kenyon, J. A.; Mehmed, O.; Kurkov, A. P.

2003-01-01

A new approach to modal analysis is presented. By applying this technique to bladed disk system identification methods, one can determine the mistuning in a rotor based on its response to a traveling wave excitation. This allows system identification to be performed under rotating conditions, and thus expands the applicability of existing mistuning identification techniques from integrally bladed rotors to conventional bladed disks.

Colorization-Based RGB-White Color Interpolation using Color Filter Array with Randomly Sampled Pattern

PubMed Central

Oh, Paul; Lee, Sukho; Kang, Moon Gi

2017-01-01

Recently, several RGB-White (RGBW) color filter arrays (CFAs) have been proposed, which have extra white (W) pixels in the filter array that are highly sensitive. Due to the high sensitivity, the W pixels have better SNR (Signal to Noise Ratio) characteristics than other color pixels in the filter array, especially, in low light conditions. However, most of the RGBW CFAs are designed so that the acquired RGBW pattern image can be converted into the conventional Bayer pattern image, which is then again converted into the final color image by using conventional demosaicing methods, i.e., color interpolation techniques. In this paper, we propose a new RGBW color filter array based on a totally different color interpolation technique, the colorization algorithm. The colorization algorithm was initially proposed for colorizing a gray image into a color image using a small number of color seeds. Here, we adopt this algorithm as a color interpolation technique, so that the RGBW color filter array can be designed with a very large number of W pixels to make the most of the highly sensitive characteristics of the W channel. The resulting RGBW color filter array has a pattern with a large proportion of W pixels, while the small-numbered RGB pixels are randomly distributed over the array. The colorization algorithm makes it possible to reconstruct the colors from such a small number of RGB values. Due to the large proportion of W pixels, the reconstructed color image has a high SNR value, especially higher than those of conventional CFAs in low light condition. Experimental results show that many important information which are not perceived in color images reconstructed with conventional CFAs are perceived in the images reconstructed with the proposed method. PMID:28657602

Colorization-Based RGB-White Color Interpolation using Color Filter Array with Randomly Sampled Pattern.

PubMed

Oh, Paul; Lee, Sukho; Kang, Moon Gi

2017-06-28

Recently, several RGB-White (RGBW) color filter arrays (CFAs) have been proposed, which have extra white (W) pixels in the filter array that are highly sensitive. Due to the high sensitivity, the W pixels have better SNR (Signal to Noise Ratio) characteristics than other color pixels in the filter array, especially, in low light conditions. However, most of the RGBW CFAs are designed so that the acquired RGBW pattern image can be converted into the conventional Bayer pattern image, which is then again converted into the final color image by using conventional demosaicing methods, i.e., color interpolation techniques. In this paper, we propose a new RGBW color filter array based on a totally different color interpolation technique, the colorization algorithm. The colorization algorithm was initially proposed for colorizing a gray image into a color image using a small number of color seeds. Here, we adopt this algorithm as a color interpolation technique, so that the RGBW color filter array can be designed with a very large number of W pixels to make the most of the highly sensitive characteristics of the W channel. The resulting RGBW color filter array has a pattern with a large proportion of W pixels, while the small-numbered RGB pixels are randomly distributed over the array. The colorization algorithm makes it possible to reconstruct the colors from such a small number of RGB values. Due to the large proportion of W pixels, the reconstructed color image has a high SNR value, especially higher than those of conventional CFAs in low light condition. Experimental results show that many important information which are not perceived in color images reconstructed with conventional CFAs are perceived in the images reconstructed with the proposed method.

Imaging of the human tooth cementum ultrastructure of archeological teeth, using hard x-ray microtomography to determine age-at-death and stress periods

NASA Astrophysics Data System (ADS)

Mani-Caplazi, Gabriela; Schulz, Georg; Deyhle, Hans; Hotz, Gerhard; Vach, Werner; Wittwer-Backofen, Ursula; Müller, Bert

2017-09-01

Tooth cementum annulation (TCA) is used by anthropologists to decipher age-at-death and stress periods based on yearly deposited incremental lines (ILs). The destructive aspect of the TCA method, which requires cutting the tooth root in sections to display the ILs, using transmission light microscopy, can be problematic for archeological teeth, and so a non-invasive imaging technique is preferred. The purpose of this study is to evaluate conventional micro computed tomography (μCT) and synchrotron radiation-based X-ray micro computed tomography (SRμCT) as a non-destructive technique to explore the tooth cementum ultrastructure and to display ILs. Seven archeological teeth from the Basel- Spitalfriedhof collection (patients died between 1845 and 1868 in the city hospital) were selected for the μCT experiments. This collection is considered a unique worldwide reference series in the anthropological science community, due to the high level of documented life history data in the medical files and the additionally collected and verified birth history by genealogists. The results demonstrate that the conventional μCT is complementary to the SRμCT allowing to prescreen the teeth using conventional μCT to identify the appropriate specimens and areas for the SRμCT measurements. SRμCT displayed cementum ring structure corresponding to the ILs in the microscope view in archeological teeth in a non-invasive fashion with the potential for more accurate assessments of ILs compared to conventional techniques. The ILs were mainly clearly visible, and it was possible to count them for age-at-death assessment and identify qualitatively irregular ILs which could constitute stress markers.

Comparison of the effects of virtual reality-based balance exercises and conventional exercises on balance and fall risk in older adults living in nursing homes in Turkey.

PubMed

Yeşilyaprak, Sevgi Sevi; Yıldırım, Meriç Şenduran; Tomruk, Murat; Ertekin, Özge; Algun, Z Candan

2016-01-01

There is limited information on effective balance training techniques including virtual reality (VR)-based balance exercises in residential settings and no studies have been designed to compare the effects of VR-based balance exercises with conventional balance exercises in older adults living in nursing homes in Turkey. The objective of our study was to investigate the effects of VR-based balance exercises on balance and fall risk in comparison to conventional balance exercises in older adults living in nursing homes. A total sample of 18 subjects (65-82 years of age) with fall history who were randomly assigned to either the VR group (Group 1, n = 7) or the conventional exercise group (Group 2, n = 11) completed the exercise training. In both groups, Berg balance score (BBS), timed up & go duration, and left leg stance and tandem stance duration with eyes closed significantly improved with time (p < 0.05), but changes were similar in both groups (p > 0.05) after training, indicating that neither the exercise method was superior. Similar improvements were found in balance and fall risk with VR-based balance training and conventional balance training in older adults living in the nursing home. Both exercise trainings can be preferable by health care professionals considering fall prevention. Appropriate patient selection is essential.

Simultaneous off-axis multiplexed holography and regular fluorescence microscopy of biological cells.

PubMed

Nygate, Yoav N; Singh, Gyanendra; Barnea, Itay; Shaked, Natan T

2018-06-01

We present a new technique for obtaining simultaneous multimodal quantitative phase and fluorescence microscopy of biological cells, providing both quantitative phase imaging and molecular specificity using a single camera. Our system is based on an interferometric multiplexing module, externally positioned at the exit of an optical microscope. In contrast to previous approaches, the presented technique allows conventional fluorescence imaging, rather than interferometric off-axis fluorescence imaging. We demonstrate the presented technique for imaging fluorescent beads and live biological cells.

Evaluation of direct and indirect additive manufacture of maxillofacial prostheses.

PubMed

Eggbeer, Dominic; Bibb, Richard; Evans, Peter; Ji, Lu

2012-09-01

The efficacy of computer-aided technologies in the design and manufacture of maxillofacial prostheses has not been fully proven. This paper presents research into the evaluation of direct and indirect additive manufacture of a maxillofacial prosthesis against conventional laboratory-based techniques. An implant/magnet-retained nasal prosthesis case from a UK maxillofacial unit was selected as a case study. A benchmark prosthesis was fabricated using conventional laboratory-based techniques for comparison against additive manufactured prostheses. For the computer-aided workflow, photogrammetry, computer-aided design and additive manufacture (AM) methods were evaluated in direct prosthesis body fabrication and indirect production using an additively manufactured mould. Qualitative analysis of position, shape, colour and edge quality was undertaken. Mechanical testing to ISO standards was also used to compare the silicone rubber used in the conventional prosthesis with the AM material. Critical evaluation has shown that utilising a computer-aided work-flow can produce a prosthesis body that is comparable to that produced using existing best practice. Technical limitations currently prevent the direct fabrication method demonstrated in this paper from being clinically viable. This research helps prosthesis providers understand the application of a computer-aided approach and guides technology developers and researchers to address the limitations identified.

Ultrasonic non invasive techniques for microbiological instrumentation

NASA Astrophysics Data System (ADS)

Elvira, L.; Sierra, C.; Galán, B.; Resa, P.

2010-01-01

Non invasive techniques based on ultrasounds have advantageous features to study, characterize and monitor microbiological and enzymatic reactions. These processes may change the sound speed, viscosity or particle distribution size of the medium where they take place, which makes possible their analysis using ultrasonic techniques. In this work, two different systems for the analysis of microbiological liquid media based on ultrasounds are presented. In first place, an industrial application based on an ultrasonic monitoring technique for microbiological growth detection in milk is shown. Such a system may improve the quality control strategies in food production factories, being able to decrease the time required to detect possible contaminations in packed products. Secondly, a study about the growing of the Escherichia coli DH5 α in different conditions is presented. It is shown that the use of ultrasonic non invasive characterization techniques in combination with other conventional measurements like optical density provides complementary information about the metabolism of these bacteria.

Consideration of techniques to mitigate the unauthorized 3D printing production of keys

NASA Astrophysics Data System (ADS)

Straub, Jeremy; Kerlin, Scott

2016-05-01

The illicit production of 3D printed keys based on remote-sensed imagery is problematic as it allows a would-be intruder to access a secured facility without the attack attempt being as obviously detectable as conventional techniques. This paper considers the problem from multiple perspectives. First, it looks at different attack types and considers the prospective attack from a digital information perspective. Second, based on this, techniques for securing keys are considered. Third, the design of keys is considered from the perspective of making them more difficult to duplicate using visible light sensing and 3D printing. Policy and legal considerations are discussed.

[Three-dimensional endoscopic endonasal study of skull base anatomy].

PubMed

Abarca-Olivas, Javier; Monjas-Cánovas, Irene; López-Álvarez, Beatriz; Lloret-García, Jaime; Sanchez-del Campo, Jose; Gras-Albert, Juan Ramon; Moreno-López, Pedro

2014-01-01

Training in dissection of the paranasal sinuses and the skull base is essential for anatomical understanding and correct surgical techniques. Three-dimensional (3D) visualisation of endoscopic skull base anatomy increases spatial orientation and allows depth perception. To show endoscopic skull base anatomy based on the 3D technique. We performed endoscopic dissection in cadaveric specimens fixed with formalin and with the Thiel technique, both prepared using intravascular injection of coloured material. Endonasal approaches were performed with conventional 2D endoscopes. Then we applied the 3D anaglyph technique to illustrate the pictures in 3D. The most important anatomical structures and landmarks of the sellar region under endonasal endoscopic vision are illustrated in 3D images. The skull base consists of complex bony and neurovascular structures. Experience with cadaver dissection is essential to understand complex anatomy and develop surgical skills. A 3D view constitutes a useful tool for understanding skull base anatomy. Copyright © 2012 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

A Novel Technique to Detect Code for SAC-OCDMA System

NASA Astrophysics Data System (ADS)

Bharti, Manisha; Kumar, Manoj; Sharma, Ajay K.

2018-04-01

The main task of optical code division multiple access (OCDMA) system is the detection of code used by a user in presence of multiple access interference (MAI). In this paper, new method of detection known as XOR subtraction detection for spectral amplitude coding OCDMA (SAC-OCDMA) based on double weight codes has been proposed and presented. As MAI is the main source of performance deterioration in OCDMA system, therefore, SAC technique is used in this paper to eliminate the effect of MAI up to a large extent. A comparative analysis is then made between the proposed scheme and other conventional detection schemes used like complimentary subtraction detection, AND subtraction detection and NAND subtraction detection. The system performance is characterized by Q-factor, BER and received optical power (ROP) with respect to input laser power and fiber length. The theoretical and simulation investigations reveal that the proposed detection technique provides better quality factor, security and received power in comparison to other conventional techniques. The wide opening of eye in case of proposed technique also proves its robustness.

Ultrasonic velocity testing of steel pipeline welded joints

NASA Astrophysics Data System (ADS)

Carreón, Hector

2017-04-01

In general the ultrasonic techniques have been used to determine the mechanical properties of materials on based of their relationship with metallurgical characteristics. In this research work, the relationship between ultrasonic velocity and phased array and the microstructure of steel pipeline welded joints is investigated. Measurements of ultrasonic wave velocity were made as a function of the location across the weld. Hardness measurements were performated in an attempt to correlate with ultrasonic response. In addition, the coarse and dendritic grain structure of the weld material is extreme and unpredictably anisotropic. Thus, due to the acoustic anisotropy of the crystal itself weld material of studied joints is anisotropic, too. Such structure is no longer direction-independent to the ultrasonic wave propagation; therefore, the ultrasonic beam deflects and redirects and the wave front becomes distorted. Thus, the use of conventional ultrasonic testing techniques using fixed beam angles is very limited and the application of conventional ultrasonic phased array techniques becomes desirable.

Estimating radiation dose to organs of patients undergoing conventional and novel multidetector CT exams using Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Angel, Erin

Advances in Computed Tomography (CT) technology have led to an increase in the modality's diagnostic capabilities and therefore its utilization, which has in turn led to an increase in radiation exposure to the patient population. As a result, CT imaging currently constitutes approximately half of the collective exposure to ionizing radiation from medical procedures. In order to understand the radiation risk, it is necessary to estimate the radiation doses absorbed by patients undergoing CT imaging. The most widely accepted risk models are based on radiosensitive organ dose as opposed to whole body dose. In this research, radiosensitive organ dose was estimated using Monte Carlo based simulations incorporating detailed multidetector CT (MDCT) scanner models, specific scan protocols, and using patient models based on accurate patient anatomy and representing a range of patient sizes. Organ dose estimates were estimated for clinical MDCT exam protocols which pose a specific concern for radiosensitive organs or regions. These dose estimates include estimation of fetal dose for pregnant patients undergoing abdomen pelvis CT exams or undergoing exams to diagnose pulmonary embolism and venous thromboembolism. Breast and lung dose were estimated for patients undergoing coronary CTA imaging, conventional fixed tube current chest CT, and conventional tube current modulated (TCM) chest CT exams. The correlation of organ dose with patient size was quantified for pregnant patients undergoing abdomen/pelvis exams and for all breast and lung dose estimates presented. Novel dose reduction techniques were developed that incorporate organ location and are specifically designed to reduce close to radiosensitive organs during CT acquisition. A generalizable model was created for simulating conventional and novel attenuation-based TCM algorithms which can be used in simulations estimating organ dose for any patient model. The generalizable model is a significant contribution of this work as it lays the foundation for the future of simulating TCM using Monte Carlo methods. As a result of this research organ dose can be estimated for individual patients undergoing specific conventional MDCT exams. This research also brings understanding to conventional and novel close reduction techniques in CT and their effect on organ dose.

Intraosseous anesthesia with solution injection controlled by a computerized system versus conventional oral anesthesia: a preliminary study.

PubMed

Beneito-Brotons, Rut; Peñarrocha-Oltra, David; Ata-Ali, Javier; Peñarrocha, María

2012-05-01

To compare a computerized intraosseous anesthesia system with the conventional oral anesthesia techniques, and analyze the latency and duration of the anesthetic effect and patient preference. A simple-blind prospective study was made between March 2007 and May 2008. Each patient was subjected to two anesthetic techniques: conventional and intraosseous using the Quicksleeper® system (DHT, Cholet, France). A split-mouth design was adopted in which each patient underwent treatment of a tooth with one of the techniques, and treatment of the homologous contralateral tooth with the other technique. The treatments consisted of restorations, endodontic procedures and simple extractions. The study series comprised 12 females and 18 males with a mean age of 36.8 years. The 30 subjects underwent a total of 60 anesthetic procedures. Intraosseous and conventional oral anesthesia caused discomfort during administration in 46.3% and 32.1% of the patients, respectively. The latency was 7.1±2.23 minutes for the conventional technique and 0.48±0.32 for intraosseous anesthesia--the difference being statistically significant. The depth of the anesthetic effect was sufficient to allow the patients to tolerate the dental treatments. The duration of the anesthetic effect in soft tissues was 199.3 minutes with the conventional technique versus only 1.6 minutes with intraosseous anesthesia--the difference between the two techniques being statistically significant. Most of the patients (69.7%) preferred intraosseous anesthesia. The described intraosseous anesthetic system is effective, with a much shorter latency than the conventional technique, sufficient duration of anesthesia to perform the required dental treatments, and with a much lesser soft tissue anesthetic effect. Most of the patients preferred intraosseous anesthesia.

Computer-assisted versus conventional free fibula flap technique for craniofacial reconstruction: an outcomes comparison.

PubMed

Seruya, Mitchel; Fisher, Mark; Rodriguez, Eduardo D

2013-11-01

There has been rising interest in computer-aided design/computer-aided manufacturing for preoperative planning and execution of osseous free flap reconstruction. The purpose of this study was to compare outcomes between computer-assisted and conventional fibula free flap techniques for craniofacial reconstruction. A two-center, retrospective review was carried out on patients who underwent fibula free flap surgery for craniofacial reconstruction from 2003 to 2012. Patients were categorized by the type of reconstructive technique: conventional (between 2003 and 2009) or computer-aided design/computer-aided manufacturing (from 2010 to 2012). Demographics, surgical factors, and perioperative and long-term outcomes were compared. A total of 68 patients underwent microsurgical craniofacial reconstruction: 58 conventional and 10 computer-aided design and manufacturing fibula free flaps. By demographics, patients undergoing the computer-aided design/computer-aided manufacturing method were significantly older and had a higher rate of radiotherapy exposure compared with conventional patients. Intraoperatively, the median number of osteotomies was significantly higher (2.0 versus 1.0, p=0.002) and the median ischemia time was significantly shorter (120 minutes versus 170 minutes, p=0.004) for the computer-aided design/computer-aided manufacturing technique compared with conventional techniques; operative times were shorter for patients undergoing the computer-aided design/computer-aided manufacturing technique, although this did not reach statistical significance. Perioperative and long-term outcomes were equivalent for the two groups, notably, hospital length of stay, recipient-site infection, partial and total flap loss, and rate of soft-tissue and bony tissue revisions. Microsurgical craniofacial reconstruction using a computer-assisted fibula flap technique yielded significantly shorter ischemia times amidst a higher number of osteotomies compared with conventional techniques. Therapeutic, III.

Intraosseous anesthesia with solution injection controlled by a computerized system versus conventional oral anesthesia: A preliminary study

PubMed Central

Beneito-Brotons, Rut; Peñarrocha-Oltra, David; Ata-Ali, Javier

2012-01-01

Objective: To compare a computerized intraosseous anesthesia system with the conventional oral anesthesia techniques, and analyze the latency and duration of the anesthetic effect and patient preference. Design: A simple-blind prospective study was made between March 2007 and May 2008. Each patient was subjected to two anesthetic techniques: conventional and intraosseous using the Quicksleeper® system (DHT, Cholet, France). A split-mouth design was adopted in which each patient underwent treatment of a tooth with one of the techniques, and treatment of the homologous contralateral tooth with the other technique. The treatments consisted of restorations, endodontic procedures and simple extractions. Results: The study series comprised 12 females and 18 males with a mean age of 36.8 years. The 30 subjects underwent a total of 60 anesthetic procedures. Intraosseous and conventional oral anesthesia caused discomfort during administration in 46.3% and 32.1% of the patients, respectively. The latency was 7.1±2.23 minutes for the conventional technique and 0.48±0.32 for intraosseous anesthesia – the difference being statistically significant. The depth of the anesthetic effect was sufficient to allow the patients to tolerate the dental treatments. The duration of the anesthetic effect in soft tissues was 199.3 minutes with the conventional technique versus only 1.6 minutes with intraosseous anesthesia – the difference between the two techniques being statistically significant. Most of the patients (69.7%) preferred intraosseous anesthesia. Conclusions: The described intraosseous anesthetic system is effective, with a much shorter latency than the conventional technique, sufficient duration of anesthesia to perform the required dental treatments, and with a much lesser soft tissue anesthetic effect. Most of the patients preferred intraosseous anesthesia. Key words:Anesthesia, intraosseous, oral anesthesia, infiltrating, mandibular block, Quicksleeper®. PMID:22143722

Hall versus conventional stainless steel crown techniques: in vitro investigation of marginal fit and microleakage using three different luting agents.

PubMed

Erdemci, Zeynep Yalçınkaya; Cehreli, S Burçak; Tirali, R Ebru

2014-01-01

This study's purpose was to investigate microleakage and marginal discrepancies in stainless steel crowns (SSCs) placed using conventional and Hall techniques and cemented with three different luting agents. Seventy-eight human primary maxillary second molars were randomly assigned to two groups (N=39), and SSCs were applied either with the Hall or conventional technique. These two groups were further subgrouped according to the material used for crown cementation (N=13 per group). Two specimens in each group were processed for scanning electron microscopy investigation. The extent of microleakage and marginal fit was quantified in millimeters on digitally photographed sections using image analysis software. The data were compared with a two-way independent and a two-way mixed analysis of variance (P=.05). The scores in the Hall group were significantly worse than those in the conventional technique group (P<.05). In both groups, resin cement displayed the lowest extent of microleakage, followed by glass ionomer and polycarboxylate cements (P<.05). Stainless steel crowns applied using the Hall technique displayed higher microleakage scores than those applied using the conventional technique, regardless of the cementation material. When the interaction of the material and technique was assessed, resin cement presented as the best choice for minimizing microleakage in both techniques.

High-quality cell block preparation from scraping of conventional cytology slide: a technical report on a modified cytoscrape cell block technique.

PubMed

Choi, Y I; Jakhongir, M; Choi, S J; Kim, L; Park, I S; Han, J Y; Kim, J M; Chu, Y C

2016-12-01

Immunocytochemistry (ICC) on formalin-fixed paraffin embedded cell blocks is an ancillary tool commonly recruited for differential diagnoses of fine needle aspiration cytology (FNAC) samples. However, the quality of conventional cell blocks in terms of adequate cellularity and evenness of distribution of cytologic material is not always satisfactory for ICC. We introduce a modified agarose-based cytoscrape cell block (CCB) technique that can be effectively used for the preparation of cell blocks from scrapings of conventional FNAC slides. A decoverslipped FNAC slide was mounted with a small amount of water. The cytological material was scraped off the slide into a tissue mold by scraping with a cell scraper. The cytoscrape material was pelleted by centrifugation and pre-embedded in ultra-low gelling temperature agarose and then re-embedded in conventional agarose. The final agarose gel disk was processed and embedded in paraffin. The quality of the ICC on the CCB sections was identical to that of the immunohistochemical stains on histological sections. By scrapping and harvesting the entirety of the cytological material off the cytology slide into a compact agarose cell button, we could avoid the risk of losing diagnostic material during the CCB preparation. This modified CCB technique enables concentration and focusing of minute material while maintaining the entire amount of the cytoscrape material on the viewing spot of the CCB sections. We believe this technique can be effectively used to improve the level of confidence in diagnosis of FNAC especially when the FNAC slides are the only sample available.

A review of X-ray explosives detection techniques for checked baggage.

PubMed

Wells, K; Bradley, D A

2012-08-01

In recent times, the security focus for civil aviation has shifted from hijacking in the 1980s, towards deliberate sabotage. X-ray imaging provides a major tool in checked baggage inspection, with various sensitive techniques being brought to bear in determining the form, and density of items within luggage as well as other material dependent parameters. This review first examines the various challenges to X-ray technology in securing a safe system of passenger transportation. An overview is then presented of the various conventional and less conventional approaches that are available to the airline industry, leading to developments in state-of-the-art imaging technology supported by enhanced machine and observer-based decision making principles. Copyright © 2012 Elsevier Ltd. All rights reserved.

Linear discriminant analysis based on L1-norm maximization.

PubMed

Zhong, Fujin; Zhang, Jiashu

2013-08-01

Linear discriminant analysis (LDA) is a well-known dimensionality reduction technique, which is widely used for many purposes. However, conventional LDA is sensitive to outliers because its objective function is based on the distance criterion using L2-norm. This paper proposes a simple but effective robust LDA version based on L1-norm maximization, which learns a set of local optimal projection vectors by maximizing the ratio of the L1-norm-based between-class dispersion and the L1-norm-based within-class dispersion. The proposed method is theoretically proved to be feasible and robust to outliers while overcoming the singular problem of the within-class scatter matrix for conventional LDA. Experiments on artificial datasets, standard classification datasets and three popular image databases demonstrate the efficacy of the proposed method.

Comparison of denture tooth movement between CAD-CAM and conventional fabrication techniques.

PubMed

Goodacre, Brian J; Goodacre, Charles J; Baba, Nadim Z; Kattadiyil, Mathew T

2018-01-01

Data comparing the denture tooth movement of computer-aided design and computer-aided manufacturing (CAD-CAM) and conventional denture processing techniques are lacking. The purpose of this in vitro study was to compare the denture tooth movement of pack-and-press, fluid resin, injection, CAD-CAM-bonded, and CAD-CAM monolithic techniques for fabricating dentures to determine which process produces the most accurate and reproducible prosthesis. A total of 50 dentures were evaluated, 10 for each of the 5 groups. A master denture was fabricated and milled from prepolymerized poly(methyl methacrylate). For the conventional processing techniques (pack-and-press, fluid resin, and injection) a polyvinyl siloxane putty mold of the master denture was made in which denture teeth were placed and molten wax injected. The cameo surface of each wax-festooned denture was laser scanned, resulting in a standard tessellation language (STL) format file. The CAD-CAM dentures included 2 subgroups: CAD-CAM-bonded teeth in which the denture teeth were bonded into the milled denture base and CAD-CAM monolithic teeth in which the denture teeth were milled as part of the denture base. After all specimens had been fabricated, they were hydrated for 24 hours, and the cameo surface laser scanned. The preprocessing and postprocessing scan files of each denture were superimposed using surface-matching software. Measurements were made at 64 locations, allowing evaluation of denture tooth movement in a buccal, lingual, mesial-distal, and occlusal direction. The use of median and interquartile range values was used to assess accuracy and reproducibility. Levene and Kruskal-Wallis analyses of variance were used to evaluate differences between processing techniques (α=.05). The CAD-CAM monolithic technique was the most accurate, followed by fluid resin, CAD-CAM-bonded, pack-and-press, and injection. CAD-CAM monolithic technique was the most reproducible, followed by pack-and-press, CAD-CAM-bonded, injection, and fluid resin. Techniques involving compression during processing showed increased positive occlusal tooth movement compared with techniques not involving compression. CAD-CAM monolithic dentures produced the best combination of accuracy and reproducibility of the tested techniques. The results from this study demonstrate that varying amounts of tooth movement can be expected depending on the processing technique. However, the clinical significance of these differences is unknown. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Accuracy of ringless casting and accelerated wax-elimination technique: a comparative in vitro study.

PubMed

Prasad, Rahul; Al-Keraif, Abdulaziz Abdullah; Kathuria, Nidhi; Gandhi, P V; Bhide, S V

2014-02-01

The purpose of this study was to determine whether the ringless casting and accelerated wax-elimination techniques can be combined to offer a cost-effective, clinically acceptable, and time-saving alternative for fabricating single unit castings in fixed prosthodontics. Sixty standardized wax copings were fabricated on a type IV stone replica of a stainless steel die. The wax patterns were divided into four groups. The first group was cast using the ringless investment technique and conventional wax-elimination method; the second group was cast using the ringless investment technique and accelerated wax-elimination method; the third group was cast using the conventional metal ring investment technique and conventional wax-elimination method; the fourth group was cast using the metal ring investment technique and accelerated wax-elimination method. The vertical marginal gap was measured at four sites per specimen, using a digital optical microscope at 100× magnification. The results were analyzed using two-way ANOVA to determine statistical significance. The vertical marginal gaps of castings fabricated using the ringless technique (76.98 ± 7.59 μm) were significantly less (p < 0.05) than those castings fabricated using the conventional metal ring technique (138.44 ± 28.59 μm); however, the vertical marginal gaps of the conventional (102.63 ± 36.12 μm) and accelerated wax-elimination (112.79 ± 38.34 μm) castings were not statistically significant (p > 0.05). The ringless investment technique can produce castings with higher accuracy and can be favorably combined with the accelerated wax-elimination method as a vital alternative to the time-consuming conventional technique of casting restorations in fixed prosthodontics. © 2013 by the American College of Prosthodontists.

Performance Analysis of Blind Subspace-Based Signature Estimation Algorithms for DS-CDMA Systems with Unknown Correlated Noise

NASA Astrophysics Data System (ADS)

Zarifi, Keyvan; Gershman, Alex B.

2006-12-01

We analyze the performance of two popular blind subspace-based signature waveform estimation techniques proposed by Wang and Poor and Buzzi and Poor for direct-sequence code division multiple-access (DS-CDMA) systems with unknown correlated noise. Using the first-order perturbation theory, analytical expressions for the mean-square error (MSE) of these algorithms are derived. We also obtain simple high SNR approximations of the MSE expressions which explicitly clarify how the performance of these techniques depends on the environmental parameters and how it is related to that of the conventional techniques that are based on the standard white noise assumption. Numerical examples further verify the consistency of the obtained analytical results with simulation results.

Simulation-based evaluation of the resolution and quantitative accuracy of temperature-modulated fluorescence tomography

PubMed Central

Lin, Yuting; Nouizi, Farouk; Kwong, Tiffany C.; Gulsen, Gultekin

2016-01-01

Conventional fluorescence tomography (FT) can recover the distribution of fluorescent agents within a highly scattering medium. However, poor spatial resolution remains its foremost limitation. Previously, we introduced a new fluorescence imaging technique termed “temperature-modulated fluorescence tomography” (TM-FT), which provides high-resolution images of fluorophore distribution. TM-FT is a multimodality technique that combines fluorescence imaging with focused ultrasound to locate thermo-sensitive fluorescence probes using a priori spatial information to drastically improve the resolution of conventional FT. In this paper, we present an extensive simulation study to evaluate the performance of the TM-FT technique on complex phantoms with multiple fluorescent targets of various sizes located at different depths. In addition, the performance of the TM-FT is tested in the presence of background fluorescence. The results obtained using our new method are systematically compared with those obtained with the conventional FT. Overall, TM-FT provides higher resolution and superior quantitative accuracy, making it an ideal candidate for in vivo preclinical and clinical imaging. For example, a 4 mm diameter inclusion positioned in the middle of a synthetic slab geometry phantom (D:40 mm × W :100 mm) is recovered as an elongated object in the conventional FT (x = 4.5 mm; y = 10.4 mm), while TM-FT recovers it successfully in both directions (x = 3.8 mm; y = 4.6 mm). As a result, the quantitative accuracy of the TM-FT is superior because it recovers the concentration of the agent with a 22% error, which is in contrast with the 83% error of the conventional FT. PMID:26368884

Measurements of Soil Carbon Dioxide Emissions from Two Maize Agroecosystems at Harvest under Different Tillage Conditions

PubMed Central

Giacomo, Gerosa; Angelo, Finco; Fabio, Boschetti; Stefano, Brenna; Riccardo, Marzuoli

2014-01-01

In this study a comparison of the soil CO2 fluxes emitted from two maize (Zea mays L.) fields with the same soil type was performed. Each field was treated with a different tillage technique: conventional tillage (30 cm depth ploughing) and no-tillage. Measurements were performed in the Po Valley (Italy) from September to October 2012, covering both pre- and postharvesting conditions, by means of two identical systems based on automatic static soil chambers. Main results show that no-tillage technique caused higher CO2 emissions than conventional tillage (on average 2.78 and 0.79 μmol CO2 m−2 s−1, resp.). This result is likely due to decomposition of the organic litter left on the ground of the no-tillage site and thus to an increased microbial and invertebrate respiration. On the other hand, fuel consumption of conventional tillage technique is greater than no-tillage consumptions. For these reasons this result cannot be taken as general. More investigations are needed to take into account all the emissions related to the field management cycle. PMID:25530990

[The anesthetic effects of Gow-Gates technique of inferior alveolar nerve block in impacted mandibular third molar extraction].

PubMed

Yang, Jieping; Liu, Wei; Gao, Qinghong

2013-08-01

To evaluate the anesthetic effects and safety of Gow-Gates technique of inferior alveolar nerve block in impacted mandibular third molar extraction. A split-mouth study was designed. The bilateral impacted mandibular third molar of 32 participants were divided into Gow-Gates technique of inferior alveolar nerve block (Gow-Gates group) and conventional technique of inferior alveolar nerve block (conventional group) randomly with third molar extracted. The anesthetic effects and adverse events were recorded. All the participants completed the research. The anesthetic success rate was 96.9% in Gow-Gates group and 90.6% in conventional group with no statistical difference ( P= 0.317); but when comparing the anesthesia grade, Gow-Gates group had a 96.9% of grade A and B, and conventional group had a rate of 78.1% (P = 0.034). And the Gow-Gates group had a much lower withdrawn bleeding than conventional group (P = 0.025). Two groups had no hematoma. Gow-Gates technique had a reliable anesthesia effects and safety in impacted mandibular third molar extraction and could be chosen as a candidate for the conventional inferior alveolar nerve block.

Ultrasonic Array for Obstacle Detection Based on CDMA with Kasami Codes

PubMed Central

Diego, Cristina; Hernández, Álvaro; Jiménez, Ana; Álvarez, Fernando J.; Sanz, Rebeca; Aparicio, Joaquín

2011-01-01

This paper raises the design of an ultrasonic array for obstacle detection based on Phased Array (PA) techniques, which steers the acoustic beam through the environment by electronics rather than mechanical means. The transmission of every element in the array has been encoded, according to Code Division for Multiple Access (CDMA), which allows multiple beams to be transmitted simultaneously. All these features together enable a parallel scanning system which does not only improve the image rate but also achieves longer inspection distances in comparison with conventional PA techniques. PMID:22247675

Single particle analysis based on Zernike phase contrast transmission electron microscopy.

PubMed

Danev, Radostin; Nagayama, Kuniaki

2008-02-01

We present the first application of Zernike phase-contrast transmission electron microscopy to single-particle 3D reconstruction of a protein, using GroEL chaperonin as the test specimen. We evaluated the performance of the technique by comparing 3D models derived from Zernike phase contrast imaging, with models from conventional underfocus phase contrast imaging. The same resolution, about 12A, was achieved by both imaging methods. The reconstruction based on Zernike phase contrast data required about 30% fewer particles. The advantages and prospects of each technique are discussed.

Conventional and microwave assisted synthesis of pyrazolone Mannich bases possessing anti-inflammatory, analgesic, ulcerogenic effect and antimicrobial properties.

PubMed

Sivakumar, Kullampalayam Krishnasamy; Rajasekaran, Aiyalu; Senthilkumar, Palaniappan; Wattamwar, Prasad P

2014-07-01

In the present study, an efficient synthesis of some Mannich base of 5-methyl-2-[(2-oxo-2H-chromen-3-yl)carbonyl]-2,4-dihydro-3H-pyrazol-3-one (4a-j) have been described by using conventional and non-conventional (microwave) techniques. Microwave assisted reactions showed that require shorter reaction time and good yield. The newly synthesized compounds were screened for their anti-inflammatory, analgesic activity, antioxidant, and antibacterial effects were compared with standard drug. Among the compounds studied, compound (4f) showing nearly equipotent anti-inflammatory and analgesic activity than the standard drug (indomethacin), along with minimum ulcerogenic index. Compounds (4b and 4i) showing 1.06 times more active than ciprofloxacin against tested Gram-negative bacteria. Copyright © 2014 Elsevier Ltd. All rights reserved.

OntoFire: an ontology-based geo-portal for wildfires

NASA Astrophysics Data System (ADS)

Kalabokidis, K.; Athanasis, N.; Vaitis, M.

2011-12-01

With the proliferation of the geospatial technologies on the Internet, the role of geo-portals (i.e. gateways to Spatial Data Infrastructures) in the area of wildfires management emerges. However, keyword-based techniques often frustrate users when looking for data of interest in geo-portal environments, while little attention has been paid to shift from the conventional keyword-based to navigation-based mechanisms. The presented OntoFire system is an ontology-based geo-portal about wildfires. Through the proposed navigation mechanisms, the relationships between the data can be discovered, which would otherwise not be possible when using conventional querying techniques alone. End users can use the browsing interface to find resources of interest by using the navigation mechanisms provided. Data providers can use the publishing interface to submit new metadata, modify metadata or removing metadata in/from the catalogue. The proposed approach can improve the discovery of valuable information that is necessary to set priorities for disaster mitigation and prevention strategies. OntoFire aspires to be a focal point of integration and management of a very large amount of information, contributing in this way to the dissemination of knowledge and to the preparedness of the operational stakeholders.

Can reliable sage-grouse lek counts be obtained using aerial infrared technology

USGS Publications Warehouse

Gillette, Gifford L.; Coates, Peter S.; Petersen, Steven; Romero, John P.

2013-01-01

More effective methods for counting greater sage-grouse (Centrocercus urophasianus) are needed to better assess population trends through enumeration or location of new leks. We describe an aerial infrared technique for conducting sage-grouse lek counts and compare this method with conventional ground-based lek count methods. During the breeding period in 2010 and 2011, we surveyed leks from fixed-winged aircraft using cryogenically cooled mid-wave infrared cameras and surveyed the same leks on the same day from the ground following a standard lek count protocol. We did not detect significant differences in lek counts between surveying techniques. These findings suggest that using a cryogenically cooled mid-wave infrared camera from an aerial platform to conduct lek surveys is an effective alternative technique to conventional ground-based methods, but further research is needed. We discuss multiple advantages to aerial infrared surveys, including counting in remote areas, representing greater spatial variation, and increasing the number of counted leks per season. Aerial infrared lek counts may be a valuable wildlife management tool that releases time and resources for other conservation efforts. Opportunities exist for wildlife professionals to refine and apply aerial infrared techniques to wildlife monitoring programs because of the increasing reliability and affordability of this technology.

CFAVC scheme for high frequency series resonant inverter-fed domestic induction heating system

NASA Astrophysics Data System (ADS)

Nagarajan, Booma; Reddy Sathi, Rama

2016-01-01

This article presents the investigations on the constant frequency asymmetric voltage cancellation control in the AC-AC resonant converter-fed domestic induction heating system. Conventional fixed frequency control techniques used in the high frequency converters lead to non-zero voltage switching operation and reduced output power. The proposed control technique produces higher output power than the conventional fixed-frequency control strategies. In this control technique, zero-voltage-switching operation is maintained during different duty cycle operation for reduction in the switching losses. Complete analysis of the induction heating power supply system with asymmetric voltage cancellation control is discussed in this article. Simulation and experimental study on constant frequency asymmetric voltage cancellation (CFAVC)-controlled full bridge series resonant inverter is performed. Time domain simulation results for the open and closed loop of the system are obtained using MATLAB simulation tool. The simulation results prove the control of voltage and power in a wide range. PID controller-based closed loop control system achieves the voltage regulation of the proposed system for the step change in load. Hardware implementation of the system under CFAVC control is done using the embedded controller. The simulation and experimental results validate the performance of the CFAVC control technique for series resonant-based induction cooking system.

Gynecomastia: glandular-liposculpture through a single transaxillary one hole incision.

PubMed

Lee, Yung Ki; Lee, Jun Hee; Kang, Sang Yoon

2018-04-01

Gynecomastia is characterized by the benign proliferation of breast tissue in men. Herein, we present a new method for the treatment of gynecomastia, using ultrasound-assisted liposuction with both conventional and reverse-cutting edge tip cannulas in combination with a pull-through lipectomy technique with pituitary forceps through a single transaxillary incision. Thirty patients were treated with this technique at the author's institution from January 2010 to January 2015. Ten patients were treated with conventional surgical excision of the glandular/fibrous breast tissue combined with liposuction through a periareolar incision before January 2010. Medical records, clinical photographs and linear analog scale scores were analyzed to compare the surgical results and complications. The patients were required to rate their cosmetic outcomes based on the linear analog scale with which they rated their own surgical results; the mean overall average score indicated a good or high level of satisfaction. There were no incidences of skin necrosis, hematoma, infection and scar contracture; however, one case each of seroma and nipple inversion did occur. Operative time was reduced overall using the new technique since it is relatively simple and straightforward. According to the evaluation by the four independent researchers, the patients treated with this new technique showed statistically significant improvements in scar and nipple-areolar complex (NAC) deformity compared to those who were treated using the conventional method. Glandular liposculpture through a single transaxillary incision is an efficient and safe technique that can provide aesthetically satisfying and consistent results.

[Virtual CT-pneumocystoscopy: indications, advantages and limitations. Our experience].

PubMed

Regine, Giovanni; Atzori, Maurizio; Buffa, Vitaliano; Miele, Vittorio; Ialongo, Pasquale; Adami, Loredana

2003-09-01

The use of CT volume-rendering techniques allows the evaluation of visceral organs without the need for endoscopy. Conventional endoscopic evaluation of the bladder is limited by the invasiveness of the technique and the difficulty exploring the entire bladder. Virtual evaluation of the bladder by three-dimensional CT reconstruction offers potential advantages and can be used in place of endoscopy. This study investigates the sensitivity of virtual CT in assessing lesion of the bladder wall to compare it with that of conventional endoscopy, and outlines the indications, advantages and disadvantages of virtual CT-pneumocystography. Between September 2001 and May 2002, 21 patients with haematuria and positive cystoscopic findings were studied. After an initial assessment by ultrasound, the patients underwent pelvic CT as a single volumetric scan after preliminary air distension of the bladder by means of 12 F Foley catheter. The images were processed on an independent workstation (Advantage 3.0 GE) running dedicated software for endoluminal navigation. The lesions detected by endoscopy were classified as sessile or pedunculated, and according to size (more or less than 5 mm). Finally, the results obtained at virtual cystoscopy were evaluated by two radiologists blinded to the conventional cystoscopy results. Thirty lesions (24 pedunculated, 6 sessile) were detected at conventional cystoscopy in 16 patients (multiple polyposis in 3 cases). Virtual cystoscopy identified 23 lesions (19 pedunculated and 4 sessile). The undetected lesions were pedunculated <5 mm (5 cases) and sessile (2 cases). One correctly identified pedunculated lesion was associated with a bladder stone. Good quality virtual images were obtained in all of the patients. In only one patient with multiple polyposis the quality of the virtual endoscopic evaluation was limited by the patient's intolerance to bladder distension, although identification of the lesions was not compromised. The overall sensitivity was 77%; this was higher for pedunculated lesions (79%) than for sessile lesions (50%). The virtual technique is less invasive and tends to be associated with fewer complications than is conventional cystoscopy. It also demonstrated a good sensitivity for evaluating pedunculated lesions, allowing evaluation of the bladder base and anterior wall, sites that are commonly poorly accessible at conventional cystoscopy. Further advantages of the virtual technique include the possibility of accurately measuring the extent of the lesion and obtaining virtual images even in patients with severe urethral obstruction and active bleeding. The limitations include the inability to obtain tissue for histologic examination or to perform endoscopic resection of pedunculated lesions. The technique is less sensitive than conventional cystoscopy in the detection of sessile lesions or very small polyps (<5 mm). Furthermore, diffuse wall thickening reduces bladder distension thereby preventing optimal evaluation. The most valuable indication appears to be the follow-up of treated wall lesions. Virtual CT-pneumocystoscopy can replace conventional cystoscopy in cases with pedunculated lesions when there is no need for biopsy, when the lesions are located at the bladder base or when cystoscopic instrumentation cannot be introduced into the bladder due to stenosis. Virtual pneumocystoscopy can also be used in the follow-up of treated polypoid lesions in association with pelvic CT-angiography.

Conventional and conformal technique of external beam radiotherapy in locally advanced cervical cancer: Dose distribution, tumor response, and side effects

NASA Astrophysics Data System (ADS)

Mutrikah, N.; Winarno, H.; Amalia, T.; Djakaria, M.

2017-08-01

The objective of this study was to compare conventional and conformal techniques of external beam radiotherapy (EBRT) in terms of the dose distribution, tumor response, and side effects in the treatment of locally advanced cervical cancer patients. A retrospective cohort study was conducted on cervical cancer patients who underwent EBRT before brachytherapy in the Radiotherapy Department of Cipto Mangunkusumo Hospital. The prescribed dose distribution, tumor response, and acute side effects of EBRT using conventional and conformal techniques were investigated. In total, 51 patients who underwent EBRT using conventional techniques (25 cases using Cobalt-60 and 26 cases using a linear accelerator (LINAC)) and 29 patients who underwent EBRT using conformal techniques were included in the study. The distribution of the prescribed dose in the target had an impact on the patient’s final response to EBRT. The complete response rate of patients to conformal techniques was significantly greater (58%) than that of patients to conventional techniques (42%). No severe acute local side effects were seen in any of the patients (Radiation Therapy Oncology Group (RTOG) grades 3-4). The distribution of the dose and volume to the gastrointestinal tract affected the proportion of mild acute side effects (RTOG grades 1-2). The urinary bladder was significantly greater using conventional techniques (Cobalt-60/LINAC) than using conformal techniques at 72% and 78% compared to 28% and 22%, respectively. The use of conformal techniques in pelvic radiation therapy is suggested in radiotherapy centers with CT simulators and 3D Radiotherapy Treatment Planning Systems (RTPSs) to decrease some uncertainties in radiotherapy planning. The use of AP/PA pelvic radiation techniques with Cobalt-60 should be limited in body thicknesses equal to or less than 18 cm. When using conformal techniques, delineation should be applied in the small bowel, as it is considered a critical organ according to RTOG consensus guidelines.

High-resolution three-dimensional visualization of the rat spinal cord microvasculature by synchrotron radiation micro-CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Jianzhong; Cao, Yong; Wu, Tianding

2014-10-15

Purpose: Understanding the three-dimensional (3D) morphology of the spinal cord microvasculature has been limited by the lack of an effective high-resolution imaging technique. In this study, synchrotron radiation microcomputed tomography (SRµCT), a novel imaging technique based on absorption imaging, was evaluated with regard to the detection of the 3D morphology of the rat spinal cord microvasculature. Methods: Ten Sprague-Dawley rats were used in this ex vivo study. After contrast agent perfusion, their spinal cords were isolated and scanned using conventional x-rays, conventional micro-CT (CµCT), and SRµCT. Results: Based on contrast agent perfusion, the microvasculature of the rat spinal cord wasmore » clearly visualized for the first time ex vivo in 3D by means of SRµCT scanning. Compared to conventional imaging techniques, SRµCT achieved higher resolution 3D vascular imaging, with the smallest vessel that could be distinguished approximately 7.4 μm in diameter. Additionally, a 3D pseudocolored image of the spinal cord microvasculature was generated in a single session of SRµCT imaging, which was conducive to detailed observation of the vessel morphology. Conclusions: The results of this study indicated that SRµCT scanning could provide higher resolution images of the vascular network of the spinal cord. This modality also has the potential to serve as a powerful imaging tool for the investigation of morphology changes in the 3D angioarchitecture of the neurovasculature in preclinical research.« less

Reachability analysis of real-time systems using time Petri nets.

PubMed

Wang, J; Deng, Y; Xu, G

2000-01-01

Time Petri nets (TPNs) are a popular Petri net model for specification and verification of real-time systems. A fundamental and most widely applied method for analyzing Petri nets is reachability analysis. The existing technique for reachability analysis of TPNs, however, is not suitable for timing property verification because one cannot derive end-to-end delay in task execution, an important issue for time-critical systems, from the reachability tree constructed using the technique. In this paper, we present a new reachability based analysis technique for TPNs for timing property analysis and verification that effectively addresses the problem. Our technique is based on a concept called clock-stamped state class (CS-class). With the reachability tree generated based on CS-classes, we can directly compute the end-to-end time delay in task execution. Moreover, a CS-class can be uniquely mapped to a traditional state class based on which the conventional reachability tree is constructed. Therefore, our CS-class-based analysis technique is more general than the existing technique. We show how to apply this technique to timing property verification of the TPN model of a command and control (C2) system.

Mass Spectrometric and Synchrotron Radiation based techniques for the identification and distribution of painting materials in samples from paints of Josep Maria Sert

PubMed Central

2012-01-01

Background Establishing the distribution of materials in paintings and that of their degradation products by imaging techniques is fundamental to understand the painting technique and can improve our knowledge on the conservation status of the painting. The combined use of chromatographic-mass spectrometric techniques, such as GC/MS or Py/GC/MS, and the chemical mapping of functional groups by imaging SR FTIR in transmission mode on thin sections and SR XRD line scans will be presented as a suitable approach to have a detailed characterisation of the materials in a paint sample, assuring their localisation in the sample build-up. This analytical approach has been used to study samples from Catalan paintings by Josep Maria Sert y Badía (20th century), a muralist achieving international recognition whose canvases adorned international buildings. Results The pigments used by the painter as well as the organic materials used as binders and varnishes could be identified by means of conventional techniques. The distribution of these materials by means of Synchrotron Radiation based techniques allowed to establish the mixtures used by the painter depending on the purpose. Conclusions Results show the suitability of the combined use of SR μFTIR and SR μXRD mapping and conventional techniques to unequivocally identify all the materials present in the sample and their localization in the sample build-up. This kind of approach becomes indispensable to solve the challenge of micro heterogeneous samples. The complementary interpretation of the data obtained with all the different techniques allowed the characterization of both organic and inorganic materials in the samples layer by layer as well as to establish the painting techniques used by Sert in the works-of-art under study. PMID:22616949

An inverter-based capacitive trans-impedance amplifier readout with offset cancellation and temporal noise reduction for IR focal plane array

NASA Astrophysics Data System (ADS)

Chen, Hsin-Han; Hsieh, Chih-Cheng

2013-09-01

This paper presents a readout integrated circuit (ROIC) with inverter-based capacitive trans-impedance amplifier (CTIA) and pseudo-multiple sampling technique for infrared focal plane array (IRFPA). The proposed inverter-based CTIA with a coupling capacitor [1], executing auto-zeroing technique to cancel out the varied offset voltage from process variation, is used to substitute differential amplifier in conventional CTIA. The tunable detector bias is applied from a global external bias before exposure. This scheme not only retains stable detector bias voltage and signal injection efficiency, but also reduces the pixel area as well. Pseudo-multiple sampling technique [2] is adopted to reduce the temporal noise of readout circuit. The noise reduction performance is comparable to the conventional multiple sampling operation without need of longer readout time proportional to the number of samples. A CMOS image sensor chip with 55×65 pixel array has been fabricated in 0.18um CMOS technology. It achieves a 12um×12um pixel size, a frame rate of 72 fps, a power-per-pixel of 0.66uW/pixel, and a readout temporal noise of 1.06mVrms (16 times of pseudo-multiple sampling), respectively.

Mathematical model of cycad cones' thermogenic temperature responses: inverse calorimetry to estimate metabolic heating rates.

PubMed

Roemer, R B; Booth, D; Bhavsar, A A; Walter, G H; Terry, L I

2012-12-21

A mathematical model based on conservation of energy has been developed and used to simulate the temperature responses of cones of the Australian cycads Macrozamia lucida and Macrozamia. macleayi during their daily thermogenic cycle. These cones generate diel midday thermogenic temperature increases as large as 12 °C above ambient during their approximately two week pollination period. The cone temperature response model is shown to accurately predict the cones' temperatures over multiple days as based on simulations of experimental results from 28 thermogenic events from 3 different cones, each simulated for either 9 or 10 sequential days. The verified model is then used as the foundation of a new, parameter estimation based technique (termed inverse calorimetry) that estimates the cones' daily metabolic heating rates from temperature measurements alone. The inverse calorimetry technique's predictions of the major features of the cones' thermogenic metabolism compare favorably with the estimates from conventional respirometry (indirect calorimetry). Because the new technique uses only temperature measurements, and does not require measurements of oxygen consumption, it provides a simple, inexpensive and portable complement to conventional respirometry for estimating metabolic heating rates. It thus provides an additional tool to facilitate field and laboratory investigations of the bio-physics of thermogenic plants. Copyright © 2012 Elsevier Ltd. All rights reserved.

Marginal and internal fit of cobalt-chromium copings fabricated using the conventional and the direct metal laser sintering techniques: A comparative in vitro study.

PubMed

Ullattuthodi, Sujana; Cherian, Kandathil Phillip; Anandkumar, R; Nambiar, M Sreedevi

2017-01-01

This in vitro study seeks to evaluate and compare the marginal and internal fit of cobalt-chromium copings fabricated using the conventional and direct metal laser sintering (DMLS) techniques. A master model of a prepared molar tooth was made using cobalt-chromium alloy. Silicone impression of the master model was made and thirty standardized working models were then produced; twenty working models for conventional lost-wax technique and ten working models for DMLS technique. A total of twenty metal copings were fabricated using two different production techniques: conventional lost-wax method and DMLS; ten samples in each group. The conventional and DMLS copings were cemented to the working models using glass ionomer cement. Marginal gap of the copings were measured at predetermined four points. The die with the cemented copings are standardized-sectioned with a heavy duty lathe. Then, each sectioned samples were analyzed for the internal gap between the die and the metal coping using a metallurgical microscope. Digital photographs were taken at ×50 magnification and analyzed using measurement software. Statistical analysis was done by unpaired t -test and analysis of variance (ANOVA). The results of this study reveal that no significant difference was present in the marginal gap of conventional and DMLS copings ( P > 0.05) by means of ANOVA. The mean values of internal gap of DMLS copings were significantly greater than that of conventional copings ( P < 0.05). Within the limitations of this in vitro study, it was concluded that the internal fit of conventional copings was superior to that of the DMLS copings. Marginal fit of the copings fabricated by two different techniques had no significant difference.

SNR Improvement of QEPAS System by Preamplifier Circuit Optimization and Frequency Locked Technique

NASA Astrophysics Data System (ADS)

Zhang, Qinduan; Chang, Jun; Wang, Zongliang; Wang, Fupeng; Jiang, Fengting; Wang, Mengyao

2018-06-01

Preamplifier circuit noise is of great importance in quartz enhanced photoacoustic spectroscopy (QEPAS) system. In this paper, several noise sources are evaluated and discussed in detail. Based on the noise characteristics, the corresponding noise reduction method is proposed. In addition, a frequency locked technique is introduced to further optimize the QEPAS system noise and improve signal, which achieves a better performance than the conventional frequency scan method. As a result, the signal-to-noise ratio (SNR) could be increased 14 times by utilizing frequency locked technique and numerical averaging technique in the QEPAS system for water vapor detection.

Does press-fit technique reduce tunnel volume enlargement after anterior cruciate ligament reconstruction with autologous hamstring tendons? A prospective randomized computed tomography study.

PubMed

Hwang, Dae-Hee; Shetty, Gautam M; Kim, Jong In; Kwon, Jae Ho; Song, Jae-Kwang; Muñoz, Michael; Lee, Jun Seop; Nha, Kyung-Wook

2013-01-01

The purpose of this prospective, randomized, computed tomography-based study was to investigate whether the press-fit technique reduces tunnel volume enlargement (TVE) and improves the clinical outcome after anterior cruciate ligament reconstruction at a minimum follow-up of 1 year compared with conventional technique. Sixty-nine patients undergoing primary ACL reconstruction using hamstring autografts were randomly allocated to either the press-fit technique group (group A) or conventional technique group (group B). All patients were evaluated for TVE and tunnel widening using computed tomography scanning, for functional outcome using International Knee Documentation Committee and Lysholm scores, for rotational stability using the pivot-shift test, and for anterior laxity using the KT-2000 arthrometer at a minimum of 1-year follow-up. There were no significant differences in TVE between the 2 groups. In group A, in which the press-fit technique was used, mean volume enlargement in the femoral tunnel was 65% compared with 71.5% in group B (P = .84). In group A, 57% (20 of 35) of patients developed femoral TVE compared with 67% (23 of 34) of patients in group B (P = .27). Both groups showed no significant difference for functional outcome (mean Lysholm score P = .73, International Knee Documentation Committee score P = .15), or knee laxity (anterior P = .78, rotational P = .22) at a minimum follow-up of 1 year. In a comparison of press-fit and conventional techniques, there were no significant differences in TVE and clinical outcome at short-term follow-up. Level II, therapeutic study, prospective randomized clinical trial. Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Rapid assessment of insect fauna based on local knowledge: comparing ecological and ethnobiological methods.

PubMed

Lima, Daniele Cristina de Oliveira; Ramos, Marcelo Alves; da Silva, Henrique Costa Hermenegildo; Alves, Angelo Giuseppe Chaves

2016-03-01

The rapid assessment of biodiversity making use of surveys of local knowledge has been successful for different biological taxa. However, there are no reports on the testing of such tools for sampling insect fauna. The present study aimed to evaluate the efficiency of different ethnobiological techniques for rapid sampling of insect fauna. Field research for the conventional survey of insect fauna was conducted on a private farm (9 ° 43'38.95 "S, 37 ° 45'11.97" W) , where there was intensive cultivation of okra (Abelmoschus esculentus L. (Moench)). The survey of local entomological knowledge was conducted among all the producers of okra living in the rural villages Pereira, Santa Luzia, and Nassau de Souza, within the Jacaré Curituba irrigated settlement scheme. The combined use of the techniques "free list" and projective interviews was analyzed, using two types of visual stimuli: stock photos and an entomological box. During the conventional survey of insect fauna, the species Bemisia tabaci biotype B, Aphis gossypii, Phenacoccus sp., Icerya purchasi and Lagria villosa were the primary pests found in the okra crop. Regarding the survey of insect pests, the results were convergent  in both techniques (conventional sampling and free list). Comparing the interview with visual stimuli (pictures) and specimen witnesses (entomological box) revealed that the latter was more effective. Techniques based on the recording and analysis of local knowledge about insects are effective for quick sampling of pest insects, but ineffective in sampling predator insects. The utilization of collected insects, infested branches, or photos of the symptoms of damage caused by pests in projective interviews is recommended.

Demosaiced pixel super-resolution in digital holography for multiplexed computational color imaging on-a-chip (Conference Presentation)

NASA Astrophysics Data System (ADS)

Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

2017-03-01

Digital holographic on-chip microscopy achieves large space-bandwidth-products (e.g., >1 billion) by making use of pixel super-resolution techniques. To synthesize a digital holographic color image, one can take three sets of holograms representing the red (R), green (G) and blue (B) parts of the spectrum and digitally combine them to synthesize a color image. The data acquisition efficiency of this sequential illumination process can be improved by 3-fold using wavelength-multiplexed R, G and B illumination that simultaneously illuminates the sample, and using a Bayer color image sensor with known or calibrated transmission spectra to digitally demultiplex these three wavelength channels. This demultiplexing step is conventionally used with interpolation-based Bayer demosaicing methods. However, because the pixels of different color channels on a Bayer image sensor chip are not at the same physical location, conventional interpolation-based demosaicing process generates strong color artifacts, especially at rapidly oscillating hologram fringes, which become even more pronounced through digital wave propagation and phase retrieval processes. Here, we demonstrate that by merging the pixel super-resolution framework into the demultiplexing process, such color artifacts can be greatly suppressed. This novel technique, termed demosaiced pixel super-resolution (D-PSR) for digital holographic imaging, achieves very similar color imaging performance compared to conventional sequential R,G,B illumination, with 3-fold improvement in image acquisition time and data-efficiency. We successfully demonstrated the color imaging performance of this approach by imaging stained Pap smears. The D-PSR technique is broadly applicable to high-throughput, high-resolution digital holographic color microscopy techniques that can be used in resource-limited-settings and point-of-care offices.

Improving Simulated Annealing by Replacing Its Variables with Game-Theoretic Utility Maximizers

NASA Technical Reports Server (NTRS)

Wolpert, David H.; Bandari, Esfandiar; Tumer, Kagan

2001-01-01

The game-theory field of Collective INtelligence (COIN) concerns the design of computer-based players engaged in a non-cooperative game so that as those players pursue their self-interests, a pre-specified global goal for the collective computational system is achieved as a side-effect. Previous implementations of COIN algorithms have outperformed conventional techniques by up to several orders of magnitude, on domains ranging from telecommunications control to optimization in congestion problems. Recent mathematical developments have revealed that these previously developed algorithms were based on only two of the three factors determining performance. Consideration of only the third factor would instead lead to conventional optimization techniques like simulated annealing that have little to do with non-cooperative games. In this paper we present an algorithm based on all three terms at once. This algorithm can be viewed as a way to modify simulated annealing by recasting it as a non-cooperative game, with each variable replaced by a player. This recasting allows us to leverage the intelligent behavior of the individual players to substantially improve the exploration step of the simulated annealing. Experiments are presented demonstrating that this recasting significantly improves simulated annealing for a model of an economic process run over an underlying small-worlds topology. Furthermore, these experiments reveal novel small-worlds phenomena, and highlight the shortcomings of conventional mechanism design in bounded rationality domains.

Mapping brain activity in gradient-echo functional MRI using principal component analysis

NASA Astrophysics Data System (ADS)

Khosla, Deepak; Singh, Manbir; Don, Manuel

1997-05-01

The detection of sites of brain activation in functional MRI has been a topic of immense research interest and many technique shave been proposed to this end. Recently, principal component analysis (PCA) has been applied to extract the activated regions and their time course of activation. This method is based on the assumption that the activation is orthogonal to other signal variations such as brain motion, physiological oscillations and other uncorrelated noises. A distinct advantage of this method is that it does not require any knowledge of the time course of the true stimulus paradigm. This technique is well suited to EPI image sequences where the sampling rate is high enough to capture the effects of physiological oscillations. In this work, we propose and apply tow methods that are based on PCA to conventional gradient-echo images and investigate their usefulness as tools to extract reliable information on brain activation. The first method is a conventional technique where a single image sequence with alternating on and off stages is subject to a principal component analysis. The second method is a PCA-based approach called the common spatial factor analysis technique (CSF). As the name suggests, this method relies on common spatial factors between the above fMRI image sequence and a background fMRI. We have applied these methods to identify active brain ares during visual stimulation and motor tasks. The results from these methods are compared to those obtained by using the standard cross-correlation technique. We found good agreement in the areas identified as active across all three techniques. The results suggest that PCA and CSF methods have good potential in detecting the true stimulus correlated changes in the presence of other interfering signals.

Revising the lower statistical limit of x-ray grating-based phase-contrast computed tomography.

PubMed

Marschner, Mathias; Birnbacher, Lorenz; Willner, Marian; Chabior, Michael; Herzen, Julia; Noël, Peter B; Pfeiffer, Franz

2017-01-01

Phase-contrast x-ray computed tomography (PCCT) is currently investigated as an interesting extension of conventional CT, providing high soft-tissue contrast even if examining weakly absorbing specimen. Until now, the potential for dose reduction was thought to be limited compared to attenuation CT, since meaningful phase retrieval fails for scans with very low photon counts when using the conventional phase retrieval method via phase stepping. In this work, we examine the statistical behaviour of the reverse projection method, an alternative phase retrieval approach and compare the results to the conventional phase retrieval technique. We investigate the noise levels in the projections as well as the image quality and quantitative accuracy of the reconstructed tomographic volumes. The results of our study show that this method performs better in a low-dose scenario than the conventional phase retrieval approach, resulting in lower noise levels, enhanced image quality and more accurate quantitative values. Overall, we demonstrate that the lower statistical limit of the phase stepping procedure as proposed by recent literature does not apply to this alternative phase retrieval technique. However, further development is necessary to overcome experimental challenges posed by this method which would enable mainstream or even clinical application of PCCT.

Least-squares model-based halftoning

NASA Astrophysics Data System (ADS)

Pappas, Thrasyvoulos N.; Neuhoff, David L.

1992-08-01

A least-squares model-based approach to digital halftoning is proposed. It exploits both a printer model and a model for visual perception. It attempts to produce an 'optimal' halftoned reproduction, by minimizing the squared error between the response of the cascade of the printer and visual models to the binary image and the response of the visual model to the original gray-scale image. Conventional methods, such as clustered ordered dither, use the properties of the eye only implicitly, and resist printer distortions at the expense of spatial and gray-scale resolution. In previous work we showed that our printer model can be used to modify error diffusion to account for printer distortions. The modified error diffusion algorithm has better spatial and gray-scale resolution than conventional techniques, but produces some well known artifacts and asymmetries because it does not make use of an explicit eye model. Least-squares model-based halftoning uses explicit eye models and relies on printer models that predict distortions and exploit them to increase, rather than decrease, both spatial and gray-scale resolution. We have shown that the one-dimensional least-squares problem, in which each row or column of the image is halftoned independently, can be implemented with the Viterbi's algorithm. Unfortunately, no closed form solution can be found in two dimensions. The two-dimensional least squares solution is obtained by iterative techniques. Experiments show that least-squares model-based halftoning produces more gray levels and better spatial resolution than conventional techniques. We also show that the least- squares approach eliminates the problems associated with error diffusion. Model-based halftoning can be especially useful in transmission of high quality documents using high fidelity gray-scale image encoders. As we have shown, in such cases halftoning can be performed at the receiver, just before printing. Apart from coding efficiency, this approach permits the halftoner to be tuned to the individual printer, whose characteristics may vary considerably from those of other printers, for example, write-black vs. write-white laser printers.

Enzyme assisted extraction of biomolecules as an approach to novel extraction technology: A review.

PubMed

Nadar, Shamraja S; Rao, Priyanka; Rathod, Virendra K

2018-06-01

An interest in the development of extraction techniques of biomolecules from various natural sources has increased in recent years due to their potential applications particularly for food and nutraceutical purposes. The presence of polysaccharides such as hemicelluloses, starch, pectin inside the cell wall, reduces the extraction efficiency of conventional extraction techniques. Conventional techniques also suffer from low extraction yields, time inefficiency and inferior extract quality due to traces of organic solvents present in them. Hence, there is a need of the green and novel extraction methods to recover biomolecules. The present review provides a holistic insight to various aspects related to enzyme aided extraction. Applications of enzymes in the recovery of various biomolecules such as polyphenols, oils, polysaccharides, flavours and colorants have been highlighted. Additionally, the employment of hyphenated extraction technologies can overcome some of the major drawbacks of enzyme based extraction such as longer extraction time and immoderate use of solvents. This review also includes hyphenated intensification techniques by coupling conventional methods with ultrasound, microwave, high pressure and supercritical carbon dioxide. The last section gives an insight on application of enzyme immobilization as a strategy for large scale extraction. Immobilization of enzymes on magnetic nanoparticles can be employed to enhance the operational performance of the system by multiple use of expensive enzymes making them industrially and economically feasible. Copyright © 2018 Elsevier Ltd. All rights reserved.

Electromagnetic interference modeling and suppression techniques in variable-frequency drive systems

NASA Astrophysics Data System (ADS)

Yang, Le; Wang, Shuo; Feng, Jianghua

2017-11-01

Electromagnetic interference (EMI) causes electromechanical damage to the motors and degrades the reliability of variable-frequency drive (VFD) systems. Unlike fundamental frequency components in motor drive systems, high-frequency EMI noise, coupled with the parasitic parameters of the trough system, are difficult to analyze and reduce. In this article, EMI modeling techniques for different function units in a VFD system, including induction motors, motor bearings, and rectifierinverters, are reviewed and evaluated in terms of applied frequency range, model parameterization, and model accuracy. The EMI models for the motors are categorized based on modeling techniques and model topologies. Motor bearing and shaft models are also reviewed, and techniques that are used to eliminate bearing current are evaluated. Modeling techniques for conventional rectifierinverter systems are also summarized. EMI noise suppression techniques, including passive filter, Wheatstone bridge balance, active filter, and optimized modulation, are reviewed and compared based on the VFD system models.

Recent advancements in nanoelectrodes and nanopipettes used in combined scanning electrochemical microscopy techniques.

PubMed

Kranz, Christine

2014-01-21

In recent years, major developments in scanning electrochemical microscopy (SECM) have significantly broadened the application range of this electroanalytical technique from high-resolution electrochemical imaging via nanoscale probes to large scale mapping using arrays of microelectrodes. A major driving force in advancing the SECM methodology is based on developing more sophisticated probes beyond conventional micro-disc electrodes usually based on noble metals or carbon microwires. This critical review focuses on the design and development of advanced electrochemical probes particularly enabling combinations of SECM with other analytical measurement techniques to provide information beyond exclusively measuring electrochemical sample properties. Consequently, this critical review will focus on recent progress and new developments towards multifunctional imaging.

Quartz Crystal Microbalance Electronic Interfacing Systems: A Review.

PubMed

Alassi, Abdulrahman; Benammar, Mohieddine; Brett, Dan

2017-12-05

Quartz Crystal Microbalance (QCM) sensors are actively being implemented in various fields due to their compatibility with different operating conditions in gaseous/liquid mediums for a wide range of measurements. This trend has been matched by the parallel advancement in tailored electronic interfacing systems for QCM sensors. That is, selecting the appropriate electronic circuit is vital for accurate sensor measurements. Many techniques were developed over time to cover the expanding measurement requirements (e.g., accommodating highly-damping environments). This paper presents a comprehensive review of the various existing QCM electronic interfacing systems. Namely, impedance-based analysis, oscillators (conventional and lock-in based techniques), exponential decay methods and the emerging phase-mass based characterization. The aforementioned methods are discussed in detail and qualitatively compared in terms of their performance for various applications. In addition, some theoretical improvements and recommendations are introduced for adequate systems implementation. Finally, specific design considerations of high-temperature microbalance systems (e.g., GaPO₄ crystals (GCM) and Langasite crystals (LCM)) are introduced, while assessing their overall system performance, stability and quality compared to conventional low-temperature applications.

Quartz Crystal Microbalance Electronic Interfacing Systems: A Review

PubMed Central

Benammar, Mohieddine; Brett, Dan

2017-01-01

Quartz Crystal Microbalance (QCM) sensors are actively being implemented in various fields due to their compatibility with different operating conditions in gaseous/liquid mediums for a wide range of measurements. This trend has been matched by the parallel advancement in tailored electronic interfacing systems for QCM sensors. That is, selecting the appropriate electronic circuit is vital for accurate sensor measurements. Many techniques were developed over time to cover the expanding measurement requirements (e.g., accommodating highly-damping environments). This paper presents a comprehensive review of the various existing QCM electronic interfacing systems. Namely, impedance-based analysis, oscillators (conventional and lock-in based techniques), exponential decay methods and the emerging phase-mass based characterization. The aforementioned methods are discussed in detail and qualitatively compared in terms of their performance for various applications. In addition, some theoretical improvements and recommendations are introduced for adequate systems implementation. Finally, specific design considerations of high-temperature microbalance systems (e.g., GaPO4 crystals (GCM) and Langasite crystals (LCM)) are introduced, while assessing their overall system performance, stability and quality compared to conventional low-temperature applications. PMID:29206212

Decision making based on data analysis and optimization algorithm applied for cogeneration systems integration into a grid

NASA Astrophysics Data System (ADS)

Asmar, Joseph Al; Lahoud, Chawki; Brouche, Marwan

2018-05-01

Cogeneration and trigeneration systems can contribute to the reduction of primary energy consumption and greenhouse gas emissions in residential and tertiary sectors, by reducing fossil fuels demand and grid losses with respect to conventional systems. The cogeneration systems are characterized by a very high energy efficiency (80 to 90%) as well as a less polluting aspect compared to the conventional energy production. The integration of these systems into the energy network must simultaneously take into account their economic and environmental challenges. In this paper, a decision-making strategy will be introduced and is divided into two parts. The first one is a strategy based on a multi-objective optimization tool with data analysis and the second part is based on an optimization algorithm. The power dispatching of the Lebanese electricity grid is then simulated and considered as a case study in order to prove the compatibility of the cogeneration power calculated by our decision-making technique. In addition, the thermal energy produced by the cogeneration systems which capacity is selected by our technique shows compatibility with the thermal demand for district heating.

Side effects and complications of intraosseous anesthesia and conventional oral anesthesia.

PubMed

Peñarrocha-Oltra, David; Ata-Ali, Javier; Oltra-Moscardó, María-José; Peñarrocha-Diago, María; Peñarrocha, Miguel

2012-05-01

To analyze the side effects and complications following intraosseous anesthesia (IA), comparing them with those of the conventional oral anesthesia techniques. A simple-blind, prospective clinical study was carried out. Each patient underwent two anesthetic techniques: conventional (local infiltration and locoregional anesthetic block) and intraosseous, for respective dental operations. In order to allow comparison of IA versus conventional anesthesia, the two operations were similar and affected the same two teeth in opposite quadrants. Heart rate was recorded in all cases before injection of the anesthetic solution and again 30 seconds after injection. The complications observed after anesthetic administration were recorded. A total of 200 oral anesthetic procedures were carried out in 100 patients. Both IA and conventional anesthesia resulted in a significant increase in heart rate, though the increase was greater with the latter technique. Incidents were infrequent with either anesthetic technique, with no significant differences between them. Regarding the complications, there were significant differences in pain at the injection site, with more intense pain in the case of IA (x2=3.532, p=0.030, Φ2=0.02), while the limitation of oral aperture was more pronounced with conventional anesthesia (x2=5.128, p<0.05, Φ2=0.014). Post-anesthetic biting showed no significant differences (x2=4.082, p=0.121, Φ2=0.009). Both anesthetic techniques significantly increased heart rate, and IA caused comparatively more pain at the injection site, while limited oral aperture was more frequent with conventional anesthesia. Post-anesthetic biting showed no significant differences between the two techniques.

A Retrospective Comparison of Conventional versus Transverse Mini-Incision Technique for Carpal Tunnel Release

PubMed Central

Gülşen, İsmail; Ak, Hakan; Evcılı, Gökhan; Balbaloglu, Özlem; Sösüncü, Enver

2013-01-01

Background. In this retrospective study, we aimed to compare the results of two surgical techniques, conventional and transverse mini-incision. Materials and Methods. 95 patients were operated between 2011 and 2012 in Bitlis State Hospital. 50 patients were operated with conventional technique and 45 of them were operated with minimal transverse incision. Postoperative complications, incision site problems, and the time of starting to use their hands in daily activities were noted. Results. 95 patients were included in the study. The mean age was 48. 87 of them were female and 8 were male. There was no problem of incision site in both of the two surgical techniques. Only in one patient, anesthesia developed in minimal incision technique. The time of starting to use their hands in daily activities was 22,2 days and 17 days in conventional and minimal incision technique, respectively. Conclusion. Two surgical techniques did not show superiority to each other in terms of postoperative complications and incision site problems except the time of starting to use their hands in daily activities. PMID:24396607

Comparison of three different adenoidectomy techniques in children - has the conventional technique been surpassed?

PubMed

Ferreira, Mayra Soares; Mangussi-Gomes, João; Ximendes, Roberta; Evangelista, Anne Rosso; Miranda, Eloá Lumi; Garcia, Leonardo Bomediano; Stamm, Aldo C

2018-01-01

Pharyngeal tonsil hyperplasia is the most frequent cause of nasal obstruction and chronic mouth breathing during childhood. Adenoidectomy is the procedure of choice for the resolution of these symptoms. It is not yet known, however, whether the conventional technique ("blind curettage") has been surpassed by more modern adenoidectomy techniques (video-assisted, with the aid of instruments). This study aimed to compare the conventional adenoidectomy technique with two other emerging techniques, performed in a reference otorhinolaryngology center. This is a prospective and observational study of 33 children submitted to adenoidectomy using 3 different techniques that were followed up for a period of 3 months after surgery. The patients were divided into 3 different groups, according to the adenoidectomy technique: Group A (conventional technique - "blind curettage"); Group B (video-assisted adenoidectomy with microdebrider); Group C (video-assisted adenoidectomy with radiofrequency - Coblation ® ). The surgical time of each procedure was measured, being considered from the moment of insertion of the mouth gag until complete hemostasis was achieved. The questionnaire for quality of life OSA-18 was applied to all caregivers on the day of the surgery and 30-90 days after the procedure. Postoperative complications were also analyzed. For the entire patient sample, there was an improvement in quality of life after the surgery (p < 0.05). When analyzing the evolution of OSA-18 index, all groups showed statistically significant improvement, for all assessed domains. There were no statistically significant differences between the 3 techniques assessed for quality of life improvement after the surgery (p > 0.05). Regarding the duration of the procedure, the conventional technique showed the shortest surgical time when compared to the others (p < 0.05). No postoperative complications were noted, for any patient. The adenoidectomy resulted in improvement of quality of life, and there were no major postoperative complications, for all operated children, regardless of the technique used. The conventional technique was faster when compared to the more modern adenoidectomy techniques. Copyright © 2017 Elsevier B.V. All rights reserved.

Digital radiography with computerized conventional monitors compared to medical monitors in vertical root fracture diagnosis.

PubMed

Tofangchiha, Maryam; Adel, Mamak; Bakhshi, Mahin; Esfehani, Mahsa; Nazeman, Pantea; Ghorbani Elizeyi, Mojgan; Javadi, Amir

2013-01-01

Vertical root fracture (VRF) is a complication which is chiefly diagnosed radiographically. Recently, film-based radiography has been substituted with digital radiography. At the moment, there is a wide range of monitors available in the market for viewing digital images. The present study aims to compare the diagnostic accuracy, sensitivity and specificity of medical and conventional monitors in detection of vertical root fractures. In this in vitro study 228 extracted single-rooted human teeth were endodontically treated. Vertical root fractures were induced in 114 samples. The teeth were imaged by a digital charge-coupled device radiography using parallel technique. The images were evaluated by a radiologist and an endodontist on two medical and conventional liquid-crystal display (LCD) monitors twice. Z-test was used to analyze the sensitivity, accuracy and specificity of each monitor. Significance level was set at 0.05. Inter and intra observer agreements were calculated by Cohen's kappa. Accuracy, specificity and sensitivity for conventional monitor were calculated as 67.5%, 72%, 62.5% respectively; and data for medical grade monitor were 67.5%, 66.5% and 68% respectively. Statistical analysis showed no significant differences in detecting VRF between the two techniques. Inter-observer agreement for conventional and medical monitor was 0.47 and 0.55 respectively (moderate). Intra-observer agreement was 0.78 for medical monitor and 0.87 for conventional one (substantial). The type of monitor does not influence diagnosis of vertical root fractures.

Non-contact Creep Resistance Measurement for Ultra-High Temperature Materials

NASA Technical Reports Server (NTRS)

Lee, J.; Bradshaw, C.; Rogers, J. R.; Rathz, T. J.; Wall, J. J.; Choo, H.; Liaw, P. K.; Hyers, R. W.

2005-01-01

Conventional techniques for measuring creep are limited to about 1700 C, so a new technique is required for higher temperatures. This technique is based on electrostatic levitation (ESL) of a spherical sample, which is rotated quickly enough to cause creep deformation by centrifugal acceleration. Creep of samples has been demonstrated at up to 2300 C in the ESL facility at NASA MSFC, while ESL itself has been applied at over 3000 C, and has no theoretical maximum temperature. The preliminary results and future directions of this NASA-funded research collaboration will be presented.

Quantitative impedimetric monitoring of cell migration under the stimulation of cytokine or anti-cancer drug in a microfluidic chip

PubMed Central

Xiao, Xia; Lei, Kin Fong; Huang, Chia-Hao

2015-01-01

Cell migration is a cellular response and results in various biological processes such as cancer metastasis, that is, the primary cause of death for cancer patients. Quantitative investigation of the correlation between cell migration and extracellular stimulation is essential for developing effective therapeutic strategies for controlling invasive cancer cells. The conventional method to determine cell migration rate based on comparison of successive images may not be an objective approach. In this work, a microfluidic chip embedded with measurement electrodes has been developed to quantitatively monitor the cell migration activity based on the impedimetric measurement technique. A no-damage wound was constructed by microfluidic phenomenon and cell migration activity under the stimulation of cytokine and an anti-cancer drug, i.e., interleukin-6 and doxorubicin, were, respectively, investigated. Impedance measurement was concurrently performed during the cell migration process. The impedance change was directly correlated to the cell migration activity; therefore, the migration rate could be calculated. In addition, a good match was found between impedance measurement and conventional imaging analysis. But the impedimetric measurement technique provides an objective and quantitative measurement. Based on our technique, cell migration rates were calculated to be 8.5, 19.1, and 34.9 μm/h under the stimulation of cytokine at concentrations of 0 (control), 5, and 10 ng/ml. This technique has high potential to be developed into a powerful analytical platform for cancer research. PMID:26180566

Covariance descriptor fusion for target detection

NASA Astrophysics Data System (ADS)

Cukur, Huseyin; Binol, Hamidullah; Bal, Abdullah; Yavuz, Fatih

2016-05-01

Target detection is one of the most important topics for military or civilian applications. In order to address such detection tasks, hyperspectral imaging sensors provide useful images data containing both spatial and spectral information. Target detection has various challenging scenarios for hyperspectral images. To overcome these challenges, covariance descriptor presents many advantages. Detection capability of the conventional covariance descriptor technique can be improved by fusion methods. In this paper, hyperspectral bands are clustered according to inter-bands correlation. Target detection is then realized by fusion of covariance descriptor results based on the band clusters. The proposed combination technique is denoted Covariance Descriptor Fusion (CDF). The efficiency of the CDF is evaluated by applying to hyperspectral imagery to detect man-made objects. The obtained results show that the CDF presents better performance than the conventional covariance descriptor.

Patterning and templating for nanoelectronics.

PubMed

Galatsis, Kosmas; Wang, Kang L; Ozkan, Mihri; Ozkan, Cengiz S; Huang, Yu; Chang, Jane P; Monbouquette, Harold G; Chen, Yong; Nealey, Paul; Botros, Youssry

2010-02-09

The semiconductor industry will soon be launching 32 nm complementary metal oxide semiconductor (CMOS) technology node using 193 nm lithography patterning technology to fabricate microprocessors with more than 2 billion transistors. To ensure the survival of Moore's law, alternative patterning techniques that offer advantages beyond conventional top-down patterning are aggressively being explored. It is evident that most alternative patterning techniques may not offer compelling advantages to succeed conventional top-down lithography for silicon integrated circuits, but alternative approaches may well indeed offer functional advantages in realising next-generation information processing nanoarchitectures such as those based on cellular, bioinsipired, magnetic dot logic, and crossbar schemes. This paper highlights and evaluates some patterning methods from the Center on Functional Engineered Nano Architectonics in Los Angeles and discusses key benchmarking criteria with respect to CMOS scaling.

An efficient ensemble learning method for gene microarray classification.

PubMed

Osareh, Alireza; Shadgar, Bita

2013-01-01

The gene microarray analysis and classification have demonstrated an effective way for the effective diagnosis of diseases and cancers. However, it has been also revealed that the basic classification techniques have intrinsic drawbacks in achieving accurate gene classification and cancer diagnosis. On the other hand, classifier ensembles have received increasing attention in various applications. Here, we address the gene classification issue using RotBoost ensemble methodology. This method is a combination of Rotation Forest and AdaBoost techniques which in turn preserve both desirable features of an ensemble architecture, that is, accuracy and diversity. To select a concise subset of informative genes, 5 different feature selection algorithms are considered. To assess the efficiency of the RotBoost, other nonensemble/ensemble techniques including Decision Trees, Support Vector Machines, Rotation Forest, AdaBoost, and Bagging are also deployed. Experimental results have revealed that the combination of the fast correlation-based feature selection method with ICA-based RotBoost ensemble is highly effective for gene classification. In fact, the proposed method can create ensemble classifiers which outperform not only the classifiers produced by the conventional machine learning but also the classifiers generated by two widely used conventional ensemble learning methods, that is, Bagging and AdaBoost.

Novel KCNQ2 channel activators discovered using fluorescence-based and automated patch-clamp-based high-throughput screening techniques

PubMed Central

Yue, Jin-feng; Qiao, Guan-hua; Liu, Ni; Nan, Fa-jun; Gao, Zhao-bing

2016-01-01

Aim: To establish an improved, high-throughput screening techniques for identifying novel KCNQ2 channel activators. Methods: KCNQ2 channels were stably expressed in CHO cells (KCNQ2 cells). Thallium flux assay was used for primary screening, and 384-well automated patch-clamp IonWorks Barracuda was used for hit validation. Two validated activators were characterized using a conventional patch-clamp recording technique. Results: From a collection of 80 000 compounds, the primary screening revealed a total of 565 compounds that potentiated the fluorescence signals in thallium flux assay by more than 150%. When the 565 hits were examined in IonWorks Barracuda, 38 compounds significantly enhanced the outward currents recorded in KCNQ2 cells, and were confirmed as KCNQ2 activators. In the conventional patch-clamp recordings, two validated activators ZG1732 and ZG2083 enhanced KCNQ2 currents with EC50 values of 1.04±0.18 μmol/L and 1.37±0.06 μmol/L, respectively. Conclusion: The combination of thallium flux assay and IonWorks Barracuda assay is an efficient high-throughput screening (HTS) route for discovering KCNQ2 activators. PMID:26725738

Advanced Feedback Methods in Information Retrieval.

ERIC Educational Resources Information Center

Salton, G.; And Others

1985-01-01

In this study, automatic feedback techniques are applied to Boolean query statements in online information retrieval to generate improved query statements based on information contained in previously retrieved documents. Feedback operations are carried out using conventional Boolean logic and extended logic. Experimental output is included to…

C style guide

NASA Technical Reports Server (NTRS)

Doland, Jerry; Valett, Jon

1994-01-01

This document discusses recommended practices and style for programmers using the C language in the Flight Dynamics Division environment. Guidelines are based on generally recommended software engineering techniques, industry resources, and local convention. The Guide offers preferred solutions to common C programming issues and illustrates through examples of C Code.

Rapid Prototyping Technique for the Fabrication of Millifluidic Devices for Polymer Formulations

NASA Astrophysics Data System (ADS)

Cabral, Joao; Harrison, Christopher; Eric, Amis; Karim, Alamgir

2003-03-01

We describe a rapid prototyping technique for the fabrication of 600 micron deep fluidic channels in a solvent-resistant polymeric matrix. Using a conventional illumination source, a laser-jet printed mask, and a commercially available thioelene-based adhesive, we demonstrate the fabrication of fluidic channels which are impervious to a wide range of solvents. The fabrication of channels with this depth by conventional lithography would be both challenging and time-consuming. We demonstrate two lithography methods: one which fabricates channels sealed between glass plates (closed face) and one which fabricates structures on a single plate (open-faced). Furthermore, we demonstrate that this technology can be used to fabricate channels with a depth which varies linearly with distance. The latter is completely compatible with silicone replication technniques. Additionally, we demonstrate that siloxane-based elastomer molds of these channels can be readily made for aqueous applications. Applications to on-line phase mapping of polymer solutions (PEO-Water-Salt) and off line phase separation studies will be discussed.

First international two-way satellite time and frequency transfer experiment employing dual pseudo-random noise codes.

PubMed

Tseng, Wen-Hung; Huang, Yi-Jiun; Gotoh, Tadahiro; Hobiger, Thomas; Fujieda, Miho; Aida, Masanori; Li, Tingyu; Lin, Shinn-Yan; Lin, Huang-Tien; Feng, Kai-Ming

2012-03-01

Two-way satellite time and frequency transfer (TWSTFT) is one of the main techniques used to compare atomic time scales over long distances. To both improve the precision of TWSTFT and decrease the satellite link fee, a new software-defined modem with dual pseudo-random noise (DPN) codes has been developed. In this paper, we demonstrate the first international DPN-based TWSTFT experiment over a period of 6 months. The results of DPN exhibit excellent performance, which is competitive with the Global Positioning System (GPS) precise point positioning (PPP) technique in the short-term and consistent with the conventional TWSTFT in the long-term. Time deviations of less than 75 ps are achieved for averaging times from 1 s to 1 d. Moreover, the DPN data has less diurnal variation than that of the conventional TWSTFT. Because the DPN-based system has advantages of higher precision and lower bandwidth cost, it is one of the most promising methods to improve international time-transfer links.

A comparative analysis of conventional cytopreparatory and liquid based cytological techniques (Sure Path) in evaluation of serous effusion fluids.

PubMed

Dadhich, Hrishikesh; Toi, Pampa Ch; Siddaraju, Neelaiah; Sevvanthi, Kalidas

2016-11-01

Clinically, detection of malignant cells in serous body fluids is critical, as their presence implies the upstaging of the disease. Cytology of body cavity fluids serves as an important tool when other diagnostic tests cannot be performed. In most laboratories, currently, the effusion fluid samples are analysed chiefly by the conventional cytopreparatory (CCP) technique. Although, there are several studies comparing the liquid-based cytology (LBC), with CCP technique in the field of cervicovaginal cytology; the literature on such comparison with respect to serous body fluid examination is sparse. One hundred samples of serous body fluids were processed by both CCP and LBC techniques. Slides prepared by these techniques were studied using six parameters. A comparative analysis of the advantages and disadvantages of the techniques in detection of malignant cells was carried out with appropriate statistical tests. The samples comprised 52 pleural, 44 peritoneal and four pericardial fluids. No statistically significant difference was noted with respect to cellularity (P values = 0.22), cell distribution (P values = 0.39) and diagnosis of malignancy (P values = 0.20). As for the remaining parameters, LBC provided statistically significant clearer smear background (P values < 0.0001) and shorter screening time (P values < 0.0001), while CPP technique provided a significantly better staining quality (P values 0.01) and sharper cytomorphologic features (P values 0.05). Although, a reduced screening time and clearer smear background are the two major advantages of LBC; the CCP technique provides the better staining quality with sharper cytomorphologic features which is more critical from the cytologic interpretation point of view. Diagn. Cytopathol. 2016;44:874-879. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

[Application of array-based comparative genomic hybridization technique in genetic analysis of patients with spontaneous abortion].

PubMed

Chu, Y; Wu, D; Hou, Q F; Huo, X D; Gao, Y; Wang, T; Wang, H D; Yang, Y L; Liao, S X

2016-08-25

To investigate the value of array-based comparative genomic hybridization (array-CGH) technique for the detection of chromosomal analysis of miscarried embryo, and to provide genetic counseling for couples with spontaneous abortion. Totally 382 patients who underwent miscarriage were enrolled in this study. All aborted tissues were analyzed with conventional cytogenetic karyotyping and array-CGH, respectively. Through genetic analysis, all of the 382 specimens were successfully analyzed by array-CGH (100.0%, 382/382), and the detection rate of chromosomal aberrations was 46.6% (178/382). However, conventional karyotype analysis was successfully performed in 281 cases (73.6%, 281/382), and 113 (40.2%, 113/281) were found with chromosomal aberrations. Of these 178 samples identified by array-CGH, 163 samples (91.6%, 163/178) were aneuploidy, 15 samples (8.4%, 15/178) were segmental deletion and (or) duplication cases. Four of 10 cases with small segmental deletion and duplication were validated to be transferred from their fathers or mathers who were carriers of submicroscopic reciprocal translocation. Of these 113 abnormal karyotypes founded by conventional karyotyping, 108 cases (95.6%, 108/113) were aneuploidy and 5 cases (4.4%, 5/113) had chromosome structural aberrations. Most array-CGH results were consistent with conventional karyotyping but with 3 cases of discrepancy, which included 2 cases of triploids, 1 case of low-level mosaicism that undetcted by array-CGH. Compared with conventional karyotyping, there is an increased detection rate of chromosomal abnormalities when array-CGH is used to analyse the products of conception, primarilly because of its sucess with nonviable tissues. It could be a first-line method to determine the reason of miscarrage with higher accuracy and sensitivity.

Non-conventional solvents in liquid phase microextraction and aqueous biphasic systems.

PubMed

An, Jiwoo; Trujillo-Rodríguez, María J; Pino, Verónica; Anderson, Jared L

2017-06-02

The development of rapid, convenient, and high throughput sample preparation approaches such as liquid phase microextraction techniques have been continuously developed over the last decade. More recently, significant attention has been given to the replacement of conventional organic solvents used in liquid phase microextraction techniques in order to reduce toxic waste and to improve selectivity and/or extraction efficiency. With these objectives, non-conventional solvents have been explored in liquid phase microextraction and aqueous biphasic systems. The utilized non-conventional solvents include ionic liquids, magnetic ionic liquids, and deep eutectic solvents. They have been widely used as extraction solvents or additives in various liquid phase microextraction modes including dispersive liquid-liquid microextraction, single-drop microextraction, hollow fiber-liquid phase microextraction, as well as in aqueous biphasic systems. This review provides an overview into the use of non-conventional solvents in these microextraction techniques in the past 5 years (2012-2016). Analytical applications of the techniques are also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

A rigorous assessment of tree height measurements obtained using airborne LIDAR and conventional field methods.

Treesearch

Hans-Erik Andersen; Stephen E. Reutebuch; Robert J. McGaughey

2006-01-01

Tree height is an important variable in forest inventory programs but is typically time-consuming and costly to measure in the field using conventional techniques. Airborne light detection and ranging (LIDAR) provides individual tree height measurements that are highly correlated with field-derived measurements, but the imprecision of conventional field techniques does...

Are conventional statistical techniques exhaustive for defining metal background concentrations in harbour sediments? A case study: The Coastal Area of Bari (Southeast Italy).

PubMed

Mali, Matilda; Dell'Anna, Maria Michela; Mastrorilli, Piero; Damiani, Leonardo; Ungaro, Nicola; Belviso, Claudia; Fiore, Saverio

2015-11-01

Sediment contamination by metals poses significant risks to coastal ecosystems and is considered to be problematic for dredging operations. The determination of the background values of metal and metalloid distribution based on site-specific variability is fundamental in assessing pollution levels in harbour sediments. The novelty of the present work consists of addressing the scope and limitation of analysing port sediments through the use of conventional statistical techniques (such as: linear regression analysis, construction of cumulative frequency curves and the iterative 2σ technique), that are commonly employed for assessing Regional Geochemical Background (RGB) values in coastal sediments. This study ascertained that although the tout court use of such techniques in determining the RGB values in harbour sediments seems appropriate (the chemical-physical parameters of port sediments fit well with statistical equations), it should nevertheless be avoided because it may be misleading and can mask key aspects of the study area that can only be revealed by further investigations, such as mineralogical and multivariate statistical analyses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Trying to detect gas-phase ions? Understanding Ion Mobility Spectrometry

PubMed Central

Cumeras, R.; Figueras, E.; Davis, C.E.; Baumbach, J.I.; Gràcia, I.

2014-01-01

Ion Mobility Spectrometry (IMS) is a widely used and ‘well-known’ technique of ion separation in gaseous phase based on the differences of ion mobilities under an electric field. This technique has received increased interest over the last several decades as evidenced by the pace and advances of new IMS devices available. In this review we explore the hyphenated techniques that are used with IMS, especially mass spectrometry as identification approach and multi-capillary column as pre-separation approach. Also, we will pay special attention to the key figures of merit of the ion mobility spectrum and how data is treated, and the influences of the experimental parameters in both a conventional drift time IMS (DTIMS) and a miniaturized IMS also known as high Field Asymmetric IMS (FAIMS) in the planar configuration. The current review article is preceded by a companion review article which details the current instrumentation and to the sections that configures both a conventional DTIMS and FAIMS devices. Those reviews will give the reader an insightful view of the main characteristics and aspects of the IMS technique. PMID:25465248

Productivity and cost estimators for conventional ground-based skidding on steep terrain using preplanned skid roads

Treesearch

Michael D. Erickson; Curt C. Hassler; Chris B. LeDoux

1991-01-01

Continuous time and motion study techniques were used to develop productivity and cost estimators for the skidding component of ground-based logging systems, operating on steep terrain using preplanned skid roads. Comparisons of productivity and costs were analyzed for an overland random access skidding method, verses a skidding method utilizing a network of preplanned...

Use of Digital Game Based Learning and Gamification in Secondary School Science: The Effect on Student Engagement, Learning and Gender Difference

ERIC Educational Resources Information Center

Khan, Amna; Ahmad, Farzana Hayat; Malik, Muhammad Muddassir

2017-01-01

This study aimed to identify the impact of a game based learning (GBL) application using computer technologies on student engagement in secondary school science classrooms. The literature reveals that conventional Science teaching techniques (teacher-centered lecture and teaching), which foster rote learning among students, are one of the major…

[Authentication of Trace Material Evidence in Forensic Science Field with Infrared Microscopic Technique].

PubMed

Jiang, Zhi-quan; Hu, Ke-liang

2016-03-01

In the field of forensic science, conventional infrared spectral analysis technique is usually unable to meet the detection requirements, because only very a few trace material evidence with diverse shapes and complex compositions, can be extracted from the crime scene. Infrared microscopic technique is developed based on a combination of Fourier-transform infrared spectroscopic technique and microscopic technique. Infrared microscopic technique has a lot of advantages over conventional infrared spectroscopic technique, such as high detection sensitivity, micro-area analysisand nondestructive examination. It has effectively solved the problem of authentication of trace material evidence in the field of forensic science. Additionally, almost no external interference is introduced during measurements by infrared microscopic technique. It can satisfy the special need that the trace material evidence must be reserved for witness in court. It is illustrated in detail through real case analysis in this experimental center that, infrared microscopic technique has advantages in authentication of trace material evidence in forensic science field. In this paper, the vibration features in infrared spectra of material evidences, including paints, plastics, rubbers, fibers, drugs and toxicants, can be comparatively analyzed by means of infrared microscopic technique, in an attempt to provide powerful spectroscopic evidence for qualitative diagnosis of various criminal and traffic accident cases. The experimental results clearly suggest that infrared microscopic technique has an incomparable advantage and it has become an effective method for authentication of trace material evidence in the field of forensic science.

Simulation-based evaluation of the resolution and quantitative accuracy of temperature-modulated fluorescence tomography.

PubMed

Lin, Yuting; Nouizi, Farouk; Kwong, Tiffany C; Gulsen, Gultekin

2015-09-01

Conventional fluorescence tomography (FT) can recover the distribution of fluorescent agents within a highly scattering medium. However, poor spatial resolution remains its foremost limitation. Previously, we introduced a new fluorescence imaging technique termed "temperature-modulated fluorescence tomography" (TM-FT), which provides high-resolution images of fluorophore distribution. TM-FT is a multimodality technique that combines fluorescence imaging with focused ultrasound to locate thermo-sensitive fluorescence probes using a priori spatial information to drastically improve the resolution of conventional FT. In this paper, we present an extensive simulation study to evaluate the performance of the TM-FT technique on complex phantoms with multiple fluorescent targets of various sizes located at different depths. In addition, the performance of the TM-FT is tested in the presence of background fluorescence. The results obtained using our new method are systematically compared with those obtained with the conventional FT. Overall, TM-FT provides higher resolution and superior quantitative accuracy, making it an ideal candidate for in vivo preclinical and clinical imaging. For example, a 4 mm diameter inclusion positioned in the middle of a synthetic slab geometry phantom (D:40  mm×W:100  mm) is recovered as an elongated object in the conventional FT (x=4.5  mm; y=10.4  mm), while TM-FT recovers it successfully in both directions (x=3.8  mm; y=4.6  mm). As a result, the quantitative accuracy of the TM-FT is superior because it recovers the concentration of the agent with a 22% error, which is in contrast with the 83% error of the conventional FT.

Modified fluoroscopy-guided sacroiliac joint injection: a technical report.

PubMed

Liliang, Po-Chou; Liang, Cheng-Loong; Lu, Kang; Weng, Hui-Ching; Syu, Fei-Kai

2014-09-01

Sacroiliac joint (SIJ) injection can occasionally be challenging. We describe our experience in using conventional technique, and we developed an adjustment to overcome difficulties incurred. Conventional technique required superimposition of the posterior and anterior SIJ lines. If this technique failed to provide entry into the joint, fluoroscopy was slightly adjusted to obtain an oblique view. Of 50 SIJ injections, 29 (58%; 44-72%) were successfully performed using conventional technique. In another 21 procedures, 18 (85.7%; 64-99%) were subsequently completed using oblique view technique. The medial joint line, viewed from this angle, corresponded to the posterior joint line in 17 cases. The lateral joint line corresponded to the posterior joint line in one case. Oblique view technique can improve the success rate of SIJ injection. Wiley Periodicals, Inc.

Discriminant locality preserving projections based on L1-norm maximization.

PubMed

Zhong, Fujin; Zhang, Jiashu; Li, Defang

2014-11-01

Conventional discriminant locality preserving projection (DLPP) is a dimensionality reduction technique based on manifold learning, which has demonstrated good performance in pattern recognition. However, because its objective function is based on the distance criterion using L2-norm, conventional DLPP is not robust to outliers which are present in many applications. This paper proposes an effective and robust DLPP version based on L1-norm maximization, which learns a set of local optimal projection vectors by maximizing the ratio of the L1-norm-based locality preserving between-class dispersion and the L1-norm-based locality preserving within-class dispersion. The proposed method is proven to be feasible and also robust to outliers while overcoming the small sample size problem. The experimental results on artificial datasets, Binary Alphadigits dataset, FERET face dataset and PolyU palmprint dataset have demonstrated the effectiveness of the proposed method.

A Novel Augmented Reality Navigation System for Endoscopic Sinus and Skull Base Surgery: A Feasibility Study

PubMed Central

Li, Liang; Yang, Jian; Chu, Yakui; Wu, Wenbo; Xue, Jin; Liang, Ping; Chen, Lei

2016-01-01

Objective To verify the reliability and clinical feasibility of a self-developed navigation system based on an augmented reality technique for endoscopic sinus and skull base surgery. Materials and Methods In this study we performed a head phantom and cadaver experiment to determine the display effect and accuracy of our navigational system. We compared cadaver head-based simulated operations, the target registration error, operation time, and National Aeronautics and Space Administration Task Load Index scores of our navigation system to conventional navigation systems. Results The navigation system developed in this study has a novel display mode capable of fusing endoscopic images to three-dimensional (3-D) virtual images. In the cadaver head experiment, the target registration error was 1.28 ± 0.45 mm, which met the accepted standards of a navigation system used for nasal endoscopic surgery. Compared with conventional navigation systems, the new system was more effective in terms of operation time and the mental workload of surgeons, which is especially important for less experienced surgeons. Conclusion The self-developed augmented reality navigation system for endoscopic sinus and skull base surgery appears to have advantages that outweigh those of conventional navigation systems. We conclude that this navigational system will provide rhinologists with more intuitive and more detailed imaging information, thus reducing the judgment time and mental workload of surgeons when performing complex sinus and skull base surgeries. Ultimately, this new navigational system has potential to increase the quality of surgeries. In addition, the augmented reality navigational system could be of interest to junior doctors being trained in endoscopic techniques because it could speed up their learning. However, it should be noted that the navigation system serves as an adjunct to a surgeon’s skills and knowledge, not as a substitute. PMID:26757365

A Novel Augmented Reality Navigation System for Endoscopic Sinus and Skull Base Surgery: A Feasibility Study.

PubMed

Li, Liang; Yang, Jian; Chu, Yakui; Wu, Wenbo; Xue, Jin; Liang, Ping; Chen, Lei

2016-01-01

To verify the reliability and clinical feasibility of a self-developed navigation system based on an augmented reality technique for endoscopic sinus and skull base surgery. In this study we performed a head phantom and cadaver experiment to determine the display effect and accuracy of our navigational system. We compared cadaver head-based simulated operations, the target registration error, operation time, and National Aeronautics and Space Administration Task Load Index scores of our navigation system to conventional navigation systems. The navigation system developed in this study has a novel display mode capable of fusing endoscopic images to three-dimensional (3-D) virtual images. In the cadaver head experiment, the target registration error was 1.28 ± 0.45 mm, which met the accepted standards of a navigation system used for nasal endoscopic surgery. Compared with conventional navigation systems, the new system was more effective in terms of operation time and the mental workload of surgeons, which is especially important for less experienced surgeons. The self-developed augmented reality navigation system for endoscopic sinus and skull base surgery appears to have advantages that outweigh those of conventional navigation systems. We conclude that this navigational system will provide rhinologists with more intuitive and more detailed imaging information, thus reducing the judgment time and mental workload of surgeons when performing complex sinus and skull base surgeries. Ultimately, this new navigational system has potential to increase the quality of surgeries. In addition, the augmented reality navigational system could be of interest to junior doctors being trained in endoscopic techniques because it could speed up their learning. However, it should be noted that the navigation system serves as an adjunct to a surgeon's skills and knowledge, not as a substitute.

Intraseptal anesthesia: a review of a relevant injection technique.

PubMed

Woodmansey, Karl

2005-01-01

Although overshadowed by intraosseous anesthesia and the periodontal ligament injection, intraseptal anesthesia remains a useful local anesthesia technique for general dentists. Intraseptal anesthesia can be employed with safety and efficacy as an alternative to conventional local infiltration or regional nerve block injections. It also can serve as an adjunctive technique when conventional techniques fail to achieve adequate local anesthesia. This article reviews the intraseptal anesthesia technique, including its indications and limitations.

Computer-Aided Diagnosis with Deep Learning Architecture: Applications to Breast Lesions in US Images and Pulmonary Nodules in CT Scans

NASA Astrophysics Data System (ADS)

Cheng, Jie-Zhi; Ni, Dong; Chou, Yi-Hong; Qin, Jing; Tiu, Chui-Mei; Chang, Yeun-Chung; Huang, Chiun-Sheng; Shen, Dinggang; Chen, Chung-Ming

2016-04-01

This paper performs a comprehensive study on the deep-learning-based computer-aided diagnosis (CADx) for the differential diagnosis of benign and malignant nodules/lesions by avoiding the potential errors caused by inaccurate image processing results (e.g., boundary segmentation), as well as the classification bias resulting from a less robust feature set, as involved in most conventional CADx algorithms. Specifically, the stacked denoising auto-encoder (SDAE) is exploited on the two CADx applications for the differentiation of breast ultrasound lesions and lung CT nodules. The SDAE architecture is well equipped with the automatic feature exploration mechanism and noise tolerance advantage, and hence may be suitable to deal with the intrinsically noisy property of medical image data from various imaging modalities. To show the outperformance of SDAE-based CADx over the conventional scheme, two latest conventional CADx algorithms are implemented for comparison. 10 times of 10-fold cross-validations are conducted to illustrate the efficacy of the SDAE-based CADx algorithm. The experimental results show the significant performance boost by the SDAE-based CADx algorithm over the two conventional methods, suggesting that deep learning techniques can potentially change the design paradigm of the CADx systems without the need of explicit design and selection of problem-oriented features.

Computer-Aided Diagnosis with Deep Learning Architecture: Applications to Breast Lesions in US Images and Pulmonary Nodules in CT Scans.

PubMed

Cheng, Jie-Zhi; Ni, Dong; Chou, Yi-Hong; Qin, Jing; Tiu, Chui-Mei; Chang, Yeun-Chung; Huang, Chiun-Sheng; Shen, Dinggang; Chen, Chung-Ming

2016-04-15

This paper performs a comprehensive study on the deep-learning-based computer-aided diagnosis (CADx) for the differential diagnosis of benign and malignant nodules/lesions by avoiding the potential errors caused by inaccurate image processing results (e.g., boundary segmentation), as well as the classification bias resulting from a less robust feature set, as involved in most conventional CADx algorithms. Specifically, the stacked denoising auto-encoder (SDAE) is exploited on the two CADx applications for the differentiation of breast ultrasound lesions and lung CT nodules. The SDAE architecture is well equipped with the automatic feature exploration mechanism and noise tolerance advantage, and hence may be suitable to deal with the intrinsically noisy property of medical image data from various imaging modalities. To show the outperformance of SDAE-based CADx over the conventional scheme, two latest conventional CADx algorithms are implemented for comparison. 10 times of 10-fold cross-validations are conducted to illustrate the efficacy of the SDAE-based CADx algorithm. The experimental results show the significant performance boost by the SDAE-based CADx algorithm over the two conventional methods, suggesting that deep learning techniques can potentially change the design paradigm of the CADx systems without the need of explicit design and selection of problem-oriented features.

Computer-Aided Diagnosis with Deep Learning Architecture: Applications to Breast Lesions in US Images and Pulmonary Nodules in CT Scans

PubMed Central

Cheng, Jie-Zhi; Ni, Dong; Chou, Yi-Hong; Qin, Jing; Tiu, Chui-Mei; Chang, Yeun-Chung; Huang, Chiun-Sheng; Shen, Dinggang; Chen, Chung-Ming

2016-01-01

This paper performs a comprehensive study on the deep-learning-based computer-aided diagnosis (CADx) for the differential diagnosis of benign and malignant nodules/lesions by avoiding the potential errors caused by inaccurate image processing results (e.g., boundary segmentation), as well as the classification bias resulting from a less robust feature set, as involved in most conventional CADx algorithms. Specifically, the stacked denoising auto-encoder (SDAE) is exploited on the two CADx applications for the differentiation of breast ultrasound lesions and lung CT nodules. The SDAE architecture is well equipped with the automatic feature exploration mechanism and noise tolerance advantage, and hence may be suitable to deal with the intrinsically noisy property of medical image data from various imaging modalities. To show the outperformance of SDAE-based CADx over the conventional scheme, two latest conventional CADx algorithms are implemented for comparison. 10 times of 10-fold cross-validations are conducted to illustrate the efficacy of the SDAE-based CADx algorithm. The experimental results show the significant performance boost by the SDAE-based CADx algorithm over the two conventional methods, suggesting that deep learning techniques can potentially change the design paradigm of the CADx systems without the need of explicit design and selection of problem-oriented features. PMID:27079888

Radar fall detection using principal component analysis

NASA Astrophysics Data System (ADS)

Jokanovic, Branka; Amin, Moeness; Ahmad, Fauzia; Boashash, Boualem

2016-05-01

Falls are a major cause of fatal and nonfatal injuries in people aged 65 years and older. Radar has the potential to become one of the leading technologies for fall detection, thereby enabling the elderly to live independently. Existing techniques for fall detection using radar are based on manual feature extraction and require significant parameter tuning in order to provide successful detections. In this paper, we employ principal component analysis for fall detection, wherein eigen images of observed motions are employed for classification. Using real data, we demonstrate that the PCA based technique provides performance improvement over the conventional feature extraction methods.

Nanoscale patterning of electronic devices at the amorphous LaAlO3/SrTiO3 oxide interface using an electron sensitive polymer mask

NASA Astrophysics Data System (ADS)

Bjørlig, Anders V.; von Soosten, Merlin; Erlandsen, Ricci; Dahm, Rasmus Tindal; Zhang, Yu; Gan, Yulin; Chen, Yunzhong; Pryds, Nini; Jespersen, Thomas S.

2018-04-01

A simple approach is presented for designing complex oxide mesoscopic electronic devices based on the conducting interfaces of room temperature grown LaAlO3/SrTiO3 heterostructures. The technique is based entirely on methods known from conventional semiconductor processing technology, and we demonstrate a lateral resolution of ˜100 nm. We study the low temperature transport properties of nanoscale wires and demonstrate the feasibility of the technique for defining in-plane gates allowing local control of the electrostatic environment in mesoscopic devices.

Cost-effective large-scale fabrication of diffractive optical elements by using conventional semiconducting processes.

PubMed

Yoo, Seunghwan; Song, Ho Young; Lee, Junghoon; Jang, Cheol-Yong; Jeong, Hakgeun

2012-11-20

In this article, we introduce a simple fabrication method for SiO(2)-based thin diffractive optical elements (DOEs) that uses the conventional processes widely used in the semiconductor industry. Photolithography and an inductively coupled plasma etching technique are easy and cost-effective methods for fabricating subnanometer-scale and thin DOEs with a refractive index of 1.45, based on SiO(2). After fabricating DOEs, we confirmed the shape of the output light emitted from the laser diode light source and applied to a light-emitting diode (LED) module. The results represent a new approach to mass-produce DOEs and realize a high-brightness LED module.

General aviation internal-combustion engine research programs at NASA-Lewis Research Center

NASA Technical Reports Server (NTRS)

Willis, E. A.

1978-01-01

An update is presented of non-turbine general aviation engine programs. The program encompasses conventional, lightweight diesel and rotary engines. It's three major thrusts are: (1) reduced SFC's; (2) improved fuels tolerance; and (3) reduced emissions. Current and planned future programs in such areas as lean operation, improved fuel management, advanced cooling techniques and advanced engine concepts, are described. These are expected to lay the technology base, by the mid to latter 1980's, for engines whose life cycle fuel costs are 30 to 50% lower than today's conventional engines.

Digital evaluation of absolute marginal discrepancy: A comparison of ceramic crowns fabricated with conventional and digital techniques.

PubMed

Liang, Shanshan; Yuan, Fusong; Luo, Xu; Yu, Zhuoren; Tang, Zhihui

2018-04-05

Marginal discrepancy is key to evaluating the accuracy of fixed dental prostheses. An improved method of evaluating marginal discrepancy is needed. The purpose of this in vitro study was to evaluate the absolute marginal discrepancy of ceramic crowns fabricated using conventional and digital methods with a digital method for the quantitative evaluation of absolute marginal discrepancy. The novel method was based on 3-dimensional scanning, iterative closest point registration techniques, and reverse engineering theory. Six standard tooth preparations for the right maxillary central incisor, right maxillary second premolar, right maxillary second molar, left mandibular lateral incisor, left mandibular first premolar, and left mandibular first molar were selected. Ten conventional ceramic crowns and 10 CEREC crowns were fabricated for each tooth preparation. A dental cast scanner was used to obtain 3-dimensional data of the preparations and ceramic crowns, and the data were compared with the "virtual seating" iterative closest point technique. Reverse engineering software used edge sharpening and other functional modules to extract the margins of the preparations and crowns. Finally, quantitative evaluation of the absolute marginal discrepancy of the ceramic crowns was obtained from the 2-dimensional cross-sectional straight-line distance between points on the margin of the ceramic crowns and the standard preparations based on the circumferential function module along the long axis. The absolute marginal discrepancy of the ceramic crowns fabricated using conventional methods was 115 ±15.2 μm, and 110 ±14.3 μm for those fabricated using the digital technique was. ANOVA showed no statistical difference between the 2 methods or among ceramic crowns for different teeth (P>.05). The digital quantitative evaluation method for the absolute marginal discrepancy of ceramic crowns was established. The evaluations determined that the absolute marginal discrepancies were within a clinically acceptable range. This method is acceptable for the digital evaluation of the accuracy of complete crowns. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Recent developments in fast kurtosis imaging

NASA Astrophysics Data System (ADS)

Hansen, Brian; Jespersen, Sune N.

2017-09-01

Diffusion kurtosis imaging (DKI) is an extension of the popular diffusion tensor imaging (DTI) technique. DKI takes into account leading deviations from Gaussian diffusion stemming from a number of effects related to the microarchitecture and compartmentalization in biological tissues. DKI therefore offers increased sensitivity to subtle microstructural alterations over conventional diffusion imaging such as DTI, as has been demonstrated in numerous reports. For this reason, interest in routine clinical application of DKI is growing rapidly. In an effort to facilitate more widespread use of DKI, recent work by our group has focused on developing experimentally fast and robust estimates of DKI metrics. A significant increase in speed is made possible by a reduction in data demand achieved through rigorous analysis of the relation between the DKI signal and the kurtosis tensor based metrics. The fast DKI methods therefore need only 13 or 19 images for DKI parameter estimation compared to more than 60 for the most modest DKI protocols applied today. Closed form solutions also ensure rapid calculation of most DKI metrics. Some parameters can even be reconstructed in real time, which may be valuable in the clinic. The fast techniques are based on conventional diffusion sequences and are therefore easily implemented on almost any clinical system, in contrast to a range of other recently proposed advanced diffusion techniques. In addition to its general applicability, this also ensures that any acceleration achieved in conventional DKI through sequence or hardware optimization will also translate directly to fast DKI acquisitions. In this review, we recapitulate the theoretical basis for the fast kurtosis techniques and their relation to conventional DKI. We then discuss the currently available variants of the fast DKI methods, their strengths and weaknesses, as well as their respective realms of application. These range from whole body applications to methods mostly suited for spinal cord or peripheral nerve, and analysis specific to brain white matter. Having covered these technical aspects, we proceed to review the fast kurtosis literature including validation studies, organ specific optimization studies and results from clinical applications.

Side effects and complications of intraosseous anesthesia and conventional oral anesthesia

PubMed Central

Peñarrocha-Oltra, David; Ata-Ali, Javier; Oltra-Moscardó, María J.; Peñarrocha, Miguel

2012-01-01

Objective: To analyze the side effects and complications following intraosseous anesthesia (IA), comparing them with those of the conventional oral anesthesia techniques. Material and method: A simple-blind, prospective clinical study was carried out. Each patient underwent two anesthetic techniques: conventional (local infiltration and locoregional anesthetic block) and intraosseous, for respective dental operations. In order to allow comparison of IA versus conventional anesthesia, the two operations were similar and affected the same two teeth in opposite quadrants. Heart rate was recorded in all cases before injection of the anesthetic solution and again 30 seconds after injection. The complications observed after anesthetic administration were recorded. Results: A total of 200 oral anesthetic procedures were carried out in 100 patients. Both IA and conventional anesthesia resulted in a significant increase in heart rate, though the increase was greater with the latter technique. Incidents were infrequent with either anesthetic technique, with no significant differences between them. Regarding the complications, there were significant differences in pain at the injection site, with more intense pain in the case of IA (x2=3.532, p=0.030, Φ2=0.02), while the limitation of oral aperture was more pronounced with conventional anesthesia (x2=5.128, p<0.05, Φ2=0.014). Post-anesthetic biting showed no significant differences (x2=4.082, p=0.121, Φ2=0.009). Conclusions: Both anesthetic techniques significantly increased heart rate, and IA caused comparatively more pain at the injection site, while limited oral aperture was more frequent with conventional anesthesia. Post-anesthetic biting showed no significant differences between the two techniques. Key words:Intraosseous anesthesia, oral anesthesia, mandibular block, heart rate, adrenalin, complications. PMID:22143716

Single-energy intensity modulated proton therapy

NASA Astrophysics Data System (ADS)

Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

2015-09-01

In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described. The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods. It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan. When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT.

Spatial Specificity in Spatiotemporal Encoding and Fourier Imaging

PubMed Central

Goerke, Ute

2015-01-01

Purpose Ultrafast imaging techniques based on spatiotemporal-encoding (SPEN), such as RASER (rapid acquisition with sequential excitation and refocusing), is a promising new class of sequences since they are largely insensitive to magnetic field variations which cause signal loss and geometric distortion in EPI. So far, attempts to theoretically describe the point-spread-function (PSF) for the original SPEN-imaging techniques have yielded limited success. To fill this gap a novel definition for an apparent PSF is proposed. Theory Spatial resolution in SPEN-imaging is determined by the spatial phase dispersion imprinted on the acquired signal by a frequency-swept excitation or refocusing pulse. The resulting signal attenuation increases with larger distance from the vertex of the quadratic phase profile. Methods Bloch simulations and experiments were performed to validate theoretical derivations. Results The apparent PSF quantifies the fractional contribution of magnetization to a voxel’s signal as a function of distance to the voxel. In contrast, the conventional PSF represents the signal intensity at various locations. Conclusion The definition of the conventional PSF fails for SPEN-imaging since only the phase of isochromats, but not the amplitude of the signal varies. The concept of the apparent PSF is shown to be generalizable to conventional Fourier- imaging techniques. PMID:26712657

Single-energy intensity modulated proton therapy.

PubMed

Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

2015-10-07

In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described.The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods.It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan.When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT.

Imaging technique for the complete edentulous patient treated conventionally or with mini implant overdenture

PubMed Central

Meleşcanu Imre, M; Preoteasa, E; Țâncu, AM; Preoteasa, CT

2013-01-01

Rationale. The imaging methods are more and more used in the clinical process of modern dentistry. Once the implant based treatment alternatives are nowadays seen as being the standard of care in edentulous patients, these techniques must be integrated in the complete denture treatment. Aim. The study presents some evaluation techniques for the edentulous patient treated by conventional dentures or mini dental implants (mini SKY Bredent) overdentures, using the profile teleradiography. These offer data useful for an optimal positioning of the artificial teeth and the mini dental implants, favoring to obtain an esthetic and functional treatment outcome. We proposed also a method to conceive a simple surgical guide that allows the prosthetically driven implants placement. Material and method. Clinical case reports were made, highlighting the importance of cephalometric evaluation on lateral teleradiographs in complete edentulous patients. A clinical case that gradually reports the surgical guide preparation (Bredent silicon radio opaque), in order to place the mini dental implants in the best prosthetic and anatomic conditions, was presented. Conclusions. The profile teleradiograph is a useful tool for the practitioner. It allows establishing the optimal site for implant placement, in a good relation with the overdenture. The conventional denture can be easily and relatively costless transformed in a surgical guide used during implant placement. PMID:23599828

Czochralski growth of NaNO3-LiNO3 solid solution single crystals using axial vibrational control technique

NASA Astrophysics Data System (ADS)

Avetissov, Igor; Sadovskiy, Andrei; Belov, Stanislav; Kong Khan, Chan; Mozhevitina, Elena; Sukhanova, Ekaterina; Zharikov, Eugeniy

2014-09-01

T-x diagram of LiNO3-NaNO3 quasi-binary system has been improved using an original technique based on Raman measurements of condense phase. (LiNO3)x(NaNO3)1-x solid solution single crystal has been grown at different regimes of axial vibrational control (AVC) technique. Significant difference in segregation coefficient behavior between AVC-CZ and conventional CZ grown crystals has appeared: with AVC intensity increase the segregation coefficient (SC) raises for light molecular weight elements, SC reduces for medium molecular weight elements, and SC remains practically unchangeable for heavy molecular weight elements. Effect of vibrational intensity on vibron and optical characteristics, microhardness of AVC-CZ (LiNO3)x(NaNO3)1-x solid solution single crystals has been studied. For the AVC-CZ crystals has been observed increases in microhardness as well as in optical transmission up to 10 rel% compare to conventional CZ grown crystals.

NCTM of liquids at high temperatures using polarization techniques

NASA Technical Reports Server (NTRS)

Krishnan, Shankar; Weber, J. K. Richard; Nordine, Paul C.; Schiffman, Robert A.

1990-01-01

Temperature measurement and control is extremely important in any materials processing application. However, conventional techniques for non-contact temperature measurement (mainly optical pyrometry) are very uncertain because of unknown or varying surface emittance. Optical properties like other properties change during processing. A dynamic, in-situ measurement of optical properties including the emittance is required. Intersonics is developing new technologies using polarized laser light scattering to determine surface emittance of freely radiating bodies concurrent with conventional optical pyrometry. These are sufficient to determine the true surface temperature of the target. Intersonics is currently developing a system called DAPP, the Division of Amplitude Polarimetric Pyrometer, that uses polarization information to measure the true thermodynamic temperature of freely radiating objects. This instrument has potential use in materials processing applications in ground and space based equipment. Results of thermophysical and thermodynamic measurements using laser reflection as a temperature measuring tool are presented. The impact of these techniques on thermophysical property measurements at high temperature is discussed.

Static in-plane shear behaviour of prefabricated wood-wool panel wallettes

NASA Astrophysics Data System (ADS)

Noh, M. S. Md; Ahmad, Z.; Ibrahim, A.; Kamarudin, A. F.; Mokhatar, S. N.

2018-04-01

The green construction material and technique are the current issue toward improving sustainability in the construction industry in Malaysia. The use of construction material that produced from renewable resources is a part of the effort for greening this industry. WWCP (Wood-wool cement panel) is a wood based product available to the construction industry to be used as a structural building wall element. This renewable material has the potential to replace the less eco-friendly materials such as bricks and other masonry element. However, the behaviour of wall subjected to the different load conditions is not well established and therefore, this study aimed to investigate the structural behaviour of the small scale wall (wallettes) subjected to in-plane lateral load. As a comparison, two types of fabrication technique of wallettes with dimension of 1200 mm × 1200 mm (± 30 mm) were considered. The conventional vertical stacking technique was denoted as W1 and new propose techniques (cross laminated) was denoted as W2. Three replicates of each type were fabricated and tested under in-plane lateral load until failure. The test results revealed that, the wallettes fabricated using the new fabrication technique significantly increased two times in load carrying capacity compared to wallettes with conventional technique.

Practical Framework for an Electron Beam Induced Current Technique Based on a Numerical Optimization Approach

NASA Astrophysics Data System (ADS)

Yamaguchi, Hideshi; Soeda, Takeshi

2015-03-01

A practical framework for an electron beam induced current (EBIC) technique has been established for conductive materials based on a numerical optimization approach. Although the conventional EBIC technique is useful for evaluating the distributions of dopants or crystal defects in semiconductor transistors, issues related to the reproducibility and quantitative capability of measurements using this technique persist. For instance, it is difficult to acquire high-quality EBIC images throughout continuous tests due to variation in operator skill or test environment. Recently, due to the evaluation of EBIC equipment performance and the numerical optimization of equipment items, the constant acquisition of high contrast images has become possible, improving the reproducibility as well as yield regardless of operator skill or test environment. The technique proposed herein is even more sensitive and quantitative than scanning probe microscopy, an imaging technique that can possibly damage the sample. The new technique is expected to benefit the electrical evaluation of fragile or soft materials along with LSI materials.

Alternate deposition and hydrogen doping technique for ZnO thin films

NASA Astrophysics Data System (ADS)

Myong, Seung Yeop; Lim, Koeng Su

2006-08-01

We propose an alternate deposition and hydrogen doping (ADHD) technique for polycrystalline hydrogen-doped ZnO thin films, which is a sublayer-by-sublayer deposition based on metalorganic chemical vapor deposition and mercury-sensitized photodecomposition of hydrogen doping gas. Compared to conventional post-deposition hydrogen doping, the ADHD process provides superior electrical conductivity, stability, and surface roughness. Photoluminescence spectra measured at 10 K reveal that the ADHD technique improves ultraviolet and violet emissions by suppressing the green and yellow emissions. Therefore, the ADHD technique is shown to be very promising aid to the manufacture of improved transparent conducting electrodes and light emitting materials.

The Sine Method: An Alternative Height Measurement Technique

Treesearch

Don C. Bragg; Lee E. Frelich; Robert T. Leverett; Will Blozan; Dale J. Luthringer

2011-01-01

Height is one of the most important dimensions of trees, but few observers are fully aware of the consequences of the misapplication of conventional height measurement techniques. A new approach, the sine method, can improve height measurement by being less sensitive to the requirements of conventional techniques (similar triangles and the tangent method). We studied...

Hot-wire anemometry in hypersonic helium flow

NASA Technical Reports Server (NTRS)

Wagner, R. D.; Weinstein, L. M.

1974-01-01

Hot-wire anemometry techniques are described that have been developed and used for hypersonic-helium-flow studies. The short run time available dictated certain innovations in applying conventional hot-wire techniques. Some examples are given to show the application of the techniques used. Modifications to conventional equipment are described, including probe modifications and probe heating controls.

Comparison of surgically induced astigmatism in patients with horizontal rectus muscle recession

PubMed Central

Çakmak, Harun; Kocatürk, Tolga; Dündar, Sema Oruç

2014-01-01

AIM To compare surgically induced astigmatism (SIA) following horizontal rectus muscle recession surgery between suspension recession with both the “hang-back” technique and conventional recession technique. METHODS Totally, 48 eyes of 24 patients who had undergone horizontal rectus muscle recession surgery were reviewed retrospectively. The patients were divided into two groups. Twelve patients were operated on by the hang-back technique (Group 1), and 12 by the conventional recession technique (Group 2). SIA was calculated on the 1st wk, 1st and in the 3rd mo after surgery using the SIA calculator. RESULTS SIA was statistically higher in the Group 1 all postoperative follow-up. SIA was the highest in the 1st wk, and decreased gradually in both groups. CONCLUSION The suspension recession technique induced much more SIA than the conventional recession technique. This difference also continued in the following visits. Therefore, the refractive power should be checked postoperatively in order to avoid refractive amblyopia. Conventional recession surgery should be the preferred method so as to minimize the postoperative refractive changes in patients with amblyopia. PMID:25161948

Comparison of computer-assisted surgery with conventional technique for the treatment of axial distal phalanx fractures in horses: an in vitro study.

PubMed

Andritzky, Juliane; Rossol, Melanie; Lischer, Christoph; Auer, Joerg A

2005-01-01

To compare the precision obtained with computer-assisted screw insertion for treatment of mid-sagittal articular fractures of the distal phalanx (P3) with results achieved with a conventional technique. In vitro experimental study. Thirty-two cadaveric equine limbs. Four groups of 8 limbs were studied. Either 1 or 2 screws were inserted perpendicular to an imaginary axial fracture of P3 using computer-assisted surgery (CAS) or conventional technique. Screw insertion time, predetermined screw length, inserted screw length, fit of the screw, and errors in placement were recorded. CAS technique took 15-20 minutes longer but resulted in greater precision of screw length and placement compared with the conventional technique. Improved precision in screw insertion with CAS makes insertion of 2 screws possible for repair of mid-sagittal P3 fractures. CAS although expensive improves precision in screw insertion into P3 and consequently should yield improved clinical outcome.

SSM-based electrophysiology.

PubMed

Schulz, Patrick; Garcia-Celma, Juan J; Fendler, Klaus

2008-10-01

An assay technique for the electrical characterization of electrogenic transport proteins on solid supported membranes is presented. Membrane vesicles, proteoliposomes or membrane fragments containing the transporter are adsorbed to the solid supported membrane and are activated by providing a substrate or a ligand via a rapid solution exchange. This technique opens up new possibilities where conventional electrophysiology fails like transporters or ion channels from bacteria and from intracellular compartments. Its rugged design and potential for automation make it suitable for drug screening.

A single-gradient junction technique to replace multiple-junction shifts for craniospinal irradiation treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadley, Austin; Ding, George X., E-mail: george.ding@vanderbilt.edu

2014-01-01

Craniospinal irradiation (CSI) requires abutting fields at the cervical spine. Junction shifts are conventionally used to prevent setup error–induced overdosage/underdosage from occurring at the same location. This study compared the dosimetric differences at the cranial-spinal junction between a single-gradient junction technique and conventional multiple-junction shifts and evaluated the effect of setup errors on the dose distributions between both techniques for a treatment course and single fraction. Conventionally, 2 lateral brain fields and a posterior spine field(s) are used for CSI with weekly 1-cm junction shifts. We retrospectively replanned 4 CSI patients using a single-gradient junction between the lateral brain fieldsmore » and the posterior spine field. The fields were extended to allow a minimum 3-cm field overlap. The dose gradient at the junction was achieved using dose painting and intensity-modulated radiation therapy planning. The effect of positioning setup errors on the dose distributions for both techniques was simulated by applying shifts of ± 3 and 5 mm. The resulting cervical spine doses across the field junction for both techniques were calculated and compared. Dose profiles were obtained for both a single fraction and entire treatment course to include the effects of the conventional weekly junction shifts. Compared with the conventional technique, the gradient-dose technique resulted in higher dose uniformity and conformity to the target volumes, lower organ at risk (OAR) mean and maximum doses, and diminished hot spots from systematic positioning errors over the course of treatment. Single-fraction hot and cold spots were improved for the gradient-dose technique. The single-gradient junction technique provides improved conformity, dose uniformity, diminished hot spots, lower OAR mean and maximum dose, and one plan for the entire treatment course, which reduces the potential human error associated with conventional 4-shifted plans.« less

Knowledge-based vision for space station object motion detection, recognition, and tracking

NASA Technical Reports Server (NTRS)

Symosek, P.; Panda, D.; Yalamanchili, S.; Wehner, W., III

1987-01-01

Computer vision, especially color image analysis and understanding, has much to offer in the area of the automation of Space Station tasks such as construction, satellite servicing, rendezvous and proximity operations, inspection, experiment monitoring, data management and training. Knowledge-based techniques improve the performance of vision algorithms for unstructured environments because of their ability to deal with imprecise a priori information or inaccurately estimated feature data and still produce useful results. Conventional techniques using statistical and purely model-based approaches lack flexibility in dealing with the variabilities anticipated in the unstructured viewing environment of space. Algorithms developed under NASA sponsorship for Space Station applications to demonstrate the value of a hypothesized architecture for a Video Image Processor (VIP) are presented. Approaches to the enhancement of the performance of these algorithms with knowledge-based techniques and the potential for deployment of highly-parallel multi-processor systems for these algorithms are discussed.

To t-Test or Not to t-Test? A p-Values-Based Point of View in the Receiver Operating Characteristic Curve Framework.

PubMed

Vexler, Albert; Yu, Jihnhee

2018-04-13

A common statistical doctrine supported by many introductory courses and textbooks is that t-test type procedures based on normally distributed data points are anticipated to provide a standard in decision-making. In order to motivate scholars to examine this convention, we introduce a simple approach based on graphical tools of receiver operating characteristic (ROC) curve analysis, a well-established biostatistical methodology. In this context, we propose employing a p-values-based method, taking into account the stochastic nature of p-values. We focus on the modern statistical literature to address the expected p-value (EPV) as a measure of the performance of decision-making rules. During the course of our study, we extend the EPV concept to be considered in terms of the ROC curve technique. This provides expressive evaluations and visualizations of a wide spectrum of testing mechanisms' properties. We show that the conventional power characterization of tests is a partial aspect of the presented EPV/ROC technique. We desire that this explanation of the EPV/ROC approach convinces researchers of the usefulness of the EPV/ROC approach for depicting different characteristics of decision-making procedures, in light of the growing interest regarding correct p-values-based applications.

Comparison of Para-Selles Bailenger/Kop-Color Fumouze, Para-Selles-Iodésine/Kop-Color II Fumouze diagnostic kits with conventional microscopic methods in identifying intestinal parasitic diseases in Senegal.

PubMed

Sow, Doudou; Dieng, Yémou; Haouchine, Djamal; Niang, Khadim; Niang, Thiane; Sylla, Khadime; Tine, Roger Clément; Ndiaye, Magatte; Ndiaye, Jean Louis; Faye, Babacar; Faye, Omar; Gaye, Oumar; Dieng, Thérèse; Izri, Arezki

2017-09-01

In the context of controlling intestinal parasites, accurate diagnosis is essential. Our objective was to evaluate the performance of new diagnostic kits compared to conventional microscopic methods in identifying intestinal parasites. Faeces collected in rural area in Senegal were subjected to several detection techniques. Thus, the sensitivity, specificity, positive and negative predictive values of new diagnostic techniques were compared to conventional merthiolate-iodine-formalin, conventional Bailenger and modified Ritchie. Furthermore, the kappa coefficient was calculated to evaluate the correlation between the new kit and those of modified Ritchie. Out of the 117 patients examined, 102 presented with a parasite, or prevalence of 87.1%. The Fumouze techniques proved to be as effective as the conventional methods in detecting flagellates and helminths with sensitivities ranging from 97 to 100%. However, conventional techniques were slightly more sensitive in identifying Endolimax nana and Blastocystis hominis . The correlation was nearly perfect (k = 0.83 and 1), respectively between Bailenger Fumouze, Iodesine Fumouze and modified Ritchie in identifying helminths while it was just acceptable (k = 0.27 and 0.28) in identifying B. hominis . The modified Ritchie technique routinely used in our laboratory remains a good diagnostic tool. However, the use of kit techniques was interesting when reading the pellet after concentration and the Colour KOP staining was a considerable contribution to the diagnosis of the vegetative forms. Therefore, it would be interesting to determine the cost of a stool test using Fumouze kit techniques to provide the most cost effective way.

Preliminary Design of a Consultation Knowledge-Based System for the Minimization of Distortion in Welded Structures

DTIC Science & Technology

1989-02-01

which capture the knowledge of such experts. These Expert Systems, or Knowledge-Based Systems’, differ from the usual computer programming techniques...their applications in the fields of structural design and welding is reviewed. 5.1 Introduction Expert Systems, or KBES, are computer programs using Al...procedurally constructed as conventional computer programs usually are; * The knowledge base of such systems is executable, unlike databases 3 "Ill

Intuitive color-based visualization of multimedia content as large graphs

NASA Astrophysics Data System (ADS)

Delest, Maylis; Don, Anthony; Benois-Pineau, Jenny

2004-06-01

Data visualization techniques are penetrating in various technological areas. In the field of multimedia such as information search and retrieval in multimedia archives, or digital media production and post-production, data visualization methodologies based on large graphs give an exciting alternative to conventional storyboard visualization. In this paper we develop a new approach to visualization of multimedia (video) documents based both on large graph clustering and preliminary video segmenting and indexing.

Biocompatibility of Resin-based Dental Materials

PubMed Central

Moharamzadeh, Keyvan; Brook, Ian M.; Van Noort, Richard

2009-01-01

Oral and mucosal adverse reactions to resin-based dental materials have been reported. Numerous studies have examined the biocompatibility of restorative dental materials and their components, and a wide range of test systems for the evaluation of the biological effects of these materials have been developed. This article reviews the biological aspects of resin-based dental materials and discusses the conventional as well as the new techniques used for biocompatibility assessment of dental materials.

Sliding Mode Control (SMC) of Robot Manipulator via Intelligent Controllers

NASA Astrophysics Data System (ADS)

Kapoor, Neha; Ohri, Jyoti

2017-02-01

Inspite of so much research, key technical problem, naming chattering of conventional, simple and robust SMC is still a challenge to the researchers and hence limits its practical application. However, newly developed soft computing based techniques can provide solution. In order to have advantages of conventional and heuristic soft computing based control techniques, in this paper various commonly used intelligent techniques, neural network, fuzzy logic and adaptive neuro fuzzy inference system (ANFIS) have been combined with sliding mode controller (SMC). For validation, proposed hybrid control schemes have been implemented for tracking a predefined trajectory by robotic manipulator, incorporating structured and unstructured uncertainties in the system. After reviewing numerous papers, all the commonly occurring uncertainties like continuous disturbance, uniform random white noise, static friction like coulomb friction and viscous friction, dynamic friction like Dhal friction and LuGre friction have been inserted in the system. Various performance indices like norm of tracking error, chattering in control input, norm of input torque, disturbance rejection, chattering rejection have been used. Comparative results show that with almost eliminated chattering the intelligent SMC controllers are found to be more efficient over simple SMC. It has also been observed from results that ANFIS based controller has the best tracking performance with the reduced burden on the system. No paper in the literature has found to have all these structured and unstructured uncertainties together for motion control of robotic manipulator.

Design of novel dual-port tapered waveguide plasma apparatus by numerical analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, D.; Zhou, R.; Yang, X. Q., E-mail: yyxxqq-mail@163.com

Microwave plasma apparatus is often of particular interest due to their superiority of low cost, electrode contamination free, and suitability for industrial production. However, there exist problems of unstable plasma and low electron density in conventional waveguide apparatus based on single port, due to low strength and non-uniformity of microwave field. This study proposes a novel dual-port tapered waveguide plasma apparatus based on power-combining technique, to improve the strength and uniformity of microwave field for the applications of plasma. A 3D model of microwave-induced plasma (field frequency 2.45 GHz) in argon at atmospheric pressure is presented. On the condition thatmore » the total input power is 500 W, simulations indicate that coherent power-combining will maximize the electric-field strength to 3.32 × 10{sup 5 }V/m and improve the uniformity of distributed microwave field, which raised 36.7% and 47.2%, respectively, compared to conventional waveguide apparatus of single port. To study the optimum conditions for industrial application, a 2D argon fluid model based on above structure is presented. It demonstrates that relatively uniform and high-density plasma is obtained at an argon flow rate of 200 ml/min. The contrastive result of electric-field distribution, electron density, and gas temperature is also valid and clearly proves the superiority of coherent power-combining to conventional technique in flow field.« less

Laboratory Workflow Analysis of Culture of Periprosthetic Tissues in Blood Culture Bottles.

PubMed

Peel, Trisha N; Sedarski, John A; Dylla, Brenda L; Shannon, Samantha K; Amirahmadi, Fazlollaah; Hughes, John G; Cheng, Allen C; Patel, Robin

2017-09-01

Culture of periprosthetic tissue specimens in blood culture bottles is more sensitive than conventional techniques, but the impact on laboratory workflow has yet to be addressed. Herein, we examined the impact of culture of periprosthetic tissues in blood culture bottles on laboratory workflow and cost. The workflow was process mapped, decision tree models were constructed using probabilities of positive and negative cultures drawn from our published study (T. N. Peel, B. L. Dylla, J. G. Hughes, D. T. Lynch, K. E. Greenwood-Quaintance, A. C. Cheng, J. N. Mandrekar, and R. Patel, mBio 7:e01776-15, 2016, https://doi.org/10.1128/mBio.01776-15), and the processing times and resource costs from the laboratory staff time viewpoint were used to compare periprosthetic tissues culture processes using conventional techniques with culture in blood culture bottles. Sensitivity analysis was performed using various rates of positive cultures. Annualized labor savings were estimated based on salary costs from the U.S. Labor Bureau for Laboratory staff. The model demonstrated a 60.1% reduction in mean total staff time with the adoption of tissue inoculation into blood culture bottles compared to conventional techniques (mean ± standard deviation, 30.7 ± 27.6 versus 77.0 ± 35.3 h per month, respectively; P < 0.001). The estimated annualized labor cost savings of culture using blood culture bottles was $10,876.83 (±$337.16). Sensitivity analysis was performed using various rates of culture positivity (5 to 50%). Culture in blood culture bottles was cost-effective, based on the estimated labor cost savings of $2,132.71 for each percent increase in test accuracy. In conclusion, culture of periprosthetic tissue in blood culture bottles is not only more accurate than but is also cost-saving compared to conventional culture methods. Copyright © 2017 American Society for Microbiology.

Single-incision Laparoscopic Surgery (SILS) in general surgery: a review of current practice.

PubMed

Froghi, Farid; Sodergren, Mikael Hans; Darzi, Ara; Paraskeva, Paraskevas

2010-08-01

Single-incision laparoscopic surgery (SILS) aims to eliminate multiple port incisions. Although general operative principles of SILS are similar to conventional laparoscopic surgery, operative techniques are not standardized. This review aims to evaluate the current use of SILS published in the literature by examining the types of operations performed, techniques employed, and relevant complications and morbidity. This review considered a total of 94 studies reporting 1889 patients evaluating 17 different general surgical operations. There were 8 different access techniques reported using conventional laparoscopic instruments and specifically designed SILS ports. There is extensive heterogeneity associated with operating methods and in particular ways of overcoming problems with retraction and instrumentation. Published complications, morbidity, and hospital length of stay are comparable to conventional laparoscopy. Although SILS provides excellent cosmetic results and morbidity seems similar to conventional laparoscopy, larger randomized controlled trials are needed to assess the safety and efficacy of this novel technique.

The German Passive: Analysis and Teaching Technique.

ERIC Educational Resources Information Center

Griffen, T. D.

1981-01-01

Proposes an analysis of German passive based upon internal structure rather than translation conventions from Latin and Greek. Claims that this approach leads to a description of the perfect participle as an adjectival complement, which eliminates the classification of a passive voice for German and simplifies the learning task. (MES)

Novel Features for Brain-Computer Interfaces

PubMed Central

Woon, W. L.; Cichocki, A.

2007-01-01

While conventional approaches of BCI feature extraction are based on the power spectrum, we have tried using nonlinear features for classifying BCI data. In this paper, we report our test results and findings, which indicate that the proposed method is a potentially useful addition to current feature extraction techniques. PMID:18364991

High-performance wavelet engine

NASA Astrophysics Data System (ADS)

Taylor, Fred J.; Mellot, Jonathon D.; Strom, Erik; Koren, Iztok; Lewis, Michael P.

1993-11-01

Wavelet processing has shown great promise for a variety of image and signal processing applications. Wavelets are also among the most computationally expensive techniques in signal processing. It is demonstrated that a wavelet engine constructed with residue number system arithmetic elements offers significant advantages over commercially available wavelet accelerators based upon conventional arithmetic elements. Analysis is presented predicting the dynamic range requirements of the reported residue number system based wavelet accelerator.

High-Accuracy Ultrasound Contrast Agent Detection Method for Diagnostic Ultrasound Imaging Systems.

PubMed

Ito, Koichi; Noro, Kazumasa; Yanagisawa, Yukari; Sakamoto, Maya; Mori, Shiro; Shiga, Kiyoto; Kodama, Tetsuya; Aoki, Takafumi

2015-12-01

An accurate method for detecting contrast agents using diagnostic ultrasound imaging systems is proposed. Contrast agents, such as microbubbles, passing through a blood vessel during ultrasound imaging are detected as blinking signals in the temporal axis, because their intensity value is constantly in motion. Ultrasound contrast agents are detected by evaluating the intensity variation of a pixel in the temporal axis. Conventional methods are based on simple subtraction of ultrasound images to detect ultrasound contrast agents. Even if the subject moves only slightly, a conventional detection method will introduce significant error. In contrast, the proposed technique employs spatiotemporal analysis of the pixel intensity variation over several frames. Experiments visualizing blood vessels in the mouse tail illustrated that the proposed method performs efficiently compared with conventional approaches. We also report that the new technique is useful for observing temporal changes in microvessel density in subiliac lymph nodes containing tumors. The results are compared with those of contrast-enhanced computed tomography. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Ultrasound Imaging Velocimetry: a review

NASA Astrophysics Data System (ADS)

Poelma, Christian

2017-01-01

Whole-field velocity measurement techniques based on ultrasound imaging (a.k.a. `ultrasound imaging velocimetry' or `echo-PIV') have received significant attention from the fluid mechanics community in the last decade, in particular because of their ability to obtain velocity fields in flows that elude characterisation by conventional optical methods. In this review, an overview is given of the history, typical components and challenges of these techniques. The basic principles of ultrasound image formation are summarised, as well as various techniques to estimate flow velocities; the emphasis is on correlation-based techniques. Examples are given for a wide range of applications, including in vivo cardiovascular flow measurements, the characterisation of sediment transport and the characterisation of complex non-Newtonian fluids. To conclude, future opportunities are identified. These encompass not just optimisation of the accuracy and dynamic range, but also extension to other application areas.

Combined CT-based and image-free navigation systems in TKA reduces postoperative outliers of rotational alignment of the tibial component.

PubMed

Mitsuhashi, Shota; Akamatsu, Yasushi; Kobayashi, Hideo; Kusayama, Yoshihiro; Kumagai, Ken; Saito, Tomoyuki

2018-02-01

Rotational malpositioning of the tibial component can lead to poor functional outcome in TKA. Although various surgical techniques have been proposed, precise rotational placement of the tibial component was difficult to accomplish even with the use of a navigation system. The purpose of this study is to assess whether combined CT-based and image-free navigation systems replicate accurately the rotational alignment of tibial component that was preoperatively planned on CT, compared with the conventional method. We compared the number of outliers for rotational alignment of the tibial component using combined CT-based and image-free navigation systems (navigated group) with those of conventional method (conventional group). Seventy-two TKAs were performed between May 2012 and December 2014. In the navigated group, the anteroposterior axis was prepared using CT-based navigation system and the tibial component was positioned under control of the navigation. In the conventional group, the tibial component was placed with reference to the Akagi line that was determined visually. Fisher's exact probability test was performed to evaluate the results. There was a significant difference between the two groups with regard to the number of outliers: 3 outliers in the navigated group compared with 12 outliers in the conventional group (P < 0.01). We concluded that combined CT-based and image-free navigation systems decreased the number of rotational outliers of tibial component, and was helpful for the replication of the accurate rotational alignment of the tibial component that was preoperatively planned.

Differential tracking data types for accurate and efficient Mars planetary navigation

NASA Technical Reports Server (NTRS)

Edwards, C. D., Jr.; Kahn, R. D.; Folkner, W. M.; Border, J. S.

1991-01-01

Ways in which high-accuracy differential observations of two or more deep space vehicles can dramatically extend the power of earth-based tracking over conventional range and Doppler tracking are discussed. Two techniques - spacecraft-spacecraft differential very long baseline interferometry (S/C-S/C Delta(VLBI)) and same-beam interferometry (SBI) - are discussed. The tracking and navigation capabilities of conventional range, Doppler, and quasar-relative Delta(VLBI) are reviewed, and the S/C-S/C Delta (VLBI) and SBI types are introduced. For each data type, the formation of the observable is discussed, an error budget describing how physical error sources manifest themselves in the observable is presented, and potential applications of the technique for Space Exploration Initiative scenarios are examined. Requirements for spacecraft and ground systems needed to enable and optimize these types of observations are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Ying; Li, Hong; Bridges, Denzel

We report that the continuing miniaturization of microelectronics is pushing advanced manufacturing into nanomanufacturing. Nanojoining is a bottom-up assembly technique that enables functional nanodevice fabrication with dissimilar nanoscopic building blocks and/or molecular components. Various conventional joining techniques have been modified and re-invented for joining nanomaterials. Our review surveys recent progress in nanojoining methods, as compared to conventional joining processes. Examples of nanojoining are given and classified by the dimensionality of the joining materials. At each classification, nanojoining is reviewed and discussed according to materials specialties, low dimensional processing features, energy input mechanisms and potential applications. The preparation of new intermetallicmore » materials by reactive nanoscale multilayer foils based on self-propagating high-temperature synthesis is highlighted. This review will provide insight into nanojoining fundamentals and innovative applications in power electronics packaging, plasmonic devices, nanosoldering for printable electronics, 3D printing and space manufacturing.« less

Nonredundant sparse feature extraction using autoencoders with receptive fields clustering.

PubMed

Ayinde, Babajide O; Zurada, Jacek M

2017-09-01

This paper proposes new techniques for data representation in the context of deep learning using agglomerative clustering. Existing autoencoder-based data representation techniques tend to produce a number of encoding and decoding receptive fields of layered autoencoders that are duplicative, thereby leading to extraction of similar features, thus resulting in filtering redundancy. We propose a way to address this problem and show that such redundancy can be eliminated. This yields smaller networks and produces unique receptive fields that extract distinct features. It is also shown that autoencoders with nonnegativity constraints on weights are capable of extracting fewer redundant features than conventional sparse autoencoders. The concept is illustrated using conventional sparse autoencoder and nonnegativity-constrained autoencoders with MNIST digits recognition, NORB normalized-uniform object data and Yale face dataset. Copyright © 2017 Elsevier Ltd. All rights reserved.

Color digital halftoning taking colorimetric color reproduction into account

NASA Astrophysics Data System (ADS)

Haneishi, Hideaki; Suzuki, Toshiaki; Shimoyama, Nobukatsu; Miyake, Yoichi

1996-01-01

Taking colorimetric color reproduction into account, the conventional error diffusion method is modified for color digital half-toning. Assuming that the input to a bilevel color printer is given in CIE-XYZ tristimulus values or CIE-LAB values instead of the more conventional RGB or YMC values, two modified versions based on vector operation in (1) the XYZ color space and (2) the LAB color space were tested. Experimental results show that the modified methods, especially the method using the LAB color space, resulted in better color reproduction performance than the conventional methods. Spatial artifacts that appear in the modified methods are presented and analyzed. It is also shown that the modified method (2) with a thresholding technique achieves a good spatial image quality.

Anovulation and ovulation induction

PubMed Central

Katsikis, I; Kita, M; Karkanaki, A; Prapas, N; Panidis, D

2006-01-01

Conventional treatment of normogonadotropic anovulatory infertility is ovulation induction using the antiestrogen clomiphene citrate, followed by follicle-stimulating hormone. Multiple follicle development, associated with ovarian hyperstimulation, and multiple pregnancy remain the major complications. Cumulative singleton and multiple pregnancy rate data after different induction treatments are needed. Newer ovulation induction interventions, such as insulin-sensitizing drugs, aromatase inhibitors and laparoscopic ovarian electrocoagulation, should be compared with conventional treatments. Ovulation induction efficiency might improve if patient subgroups with altered chances for success or complications with new or conventional techniques could be identified, using multivariate prediction models based on initial screening characteristics. This would make ovulation induction more cost-effective, safe and convenient, enabling doctors to advise patients on the most effective and patient-tailored treatment strategy. PMID:20351807

Accelerators for Cancer Therapy

DOE R&D Accomplishments Database

Lennox, Arlene J.

2000-05-30

The vast majority of radiation treatments for cancerous tumors are given using electron linacs that provide both electrons and photons at several energies. Design and construction of these linacs are based on mature technology that is rapidly becoming more and more standardized and sophisticated. The use of hadrons such as neutrons, protons, alphas, or carbon, oxygen and neon ions is relatively new. Accelerators for hadron therapy are far from standardized, but the use of hadron therapy as an alternative to conventional radiation has led to significant improvements and refinements in conventional treatment techniques. This paper presents the rationale for radiation therapy, describes the accelerators used in conventional and hadron therapy, and outlines the issues that must still be resolved in the emerging field of hadron therapy.

TH-C-BRC-03: Emerging Linac Based SRS/SBRT Technologies with Modulated Arc Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, L.

2016-06-15

The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioningmore » capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to deliver highly conformal radiosurgery treatments to multiple targets simultaneously via a single isocenter to replace the conventional multi-iso multi-plan treatments. It becomes important to understand the advantages and limitations of this technique, and the pitfalls for implementing this technique in clinical practice. The planning process of single-iso multi-target MAT will be described, and its plan quality and delivery efficiency will be compared with multi-iso plans. The QA process for verifying such complex plans will be illustrated, and pitfalls in imaging and patient set up will be discussed. Overall, this session will focus on the following areas: 1) Update on the emerging technology in current SRS/SBRT delivery. 2) New developments in treatment planning and Quality Assurance program. 3) Imaging guidance and motion management. Learning Objectives: To understand the SRS/SBRT principles and its clinical applications, and gain knowledge on the emerging technologies in SRS/SBRT. To review planning concepts and useful tips in treatment planning. To learn about the imaging guidance procedures and the quality assurance program in SRS/SBRT. National Institutes of Health, Varian Medical System; L. Ren, The presenter is funded by National Institutes of Health and Varian Medical System.« less

Secure positioning technique based on encrypted visible light map for smart indoor service

NASA Astrophysics Data System (ADS)

Lee, Yong Up; Jung, Gillyoung

2018-03-01

Indoor visible light (VL) positioning systems for smart indoor services are negatively affected by both cochannel interference from adjacent light sources and VL reception position irregularity in the three-dimensional (3-D) VL channel. A secure positioning methodology based on a two-dimensional (2-D) encrypted VL map is proposed, implemented in prototypes of the specific positioning system, and analyzed based on performance tests. The proposed positioning technique enhances the positioning performance by more than 21.7% compared to the conventional method in real VL positioning tests. Further, the pseudonoise code is found to be the optimal encryption key for secure VL positioning for this smart indoor service.

Head ballistocardiogram based on wireless multi-location sensors.

PubMed

Onizuka, Kohei; Sodini, Charles G

2015-08-01

Recently a wearable BCG monitoring technique based on an accelerometer worn at the ear was demonstrated to replace a conventional bulky BCG acquisition system. In this work, a multi-location wireless vital signs monitor was developed, and at least two common acceleration vectors correlating to sitting-BCG were found in the supine position by using head PPG signal as a reference for eight healthy human subjects. The head side amplitude in the supine position is roughly proportional to the sitting amplitude that is in turn proportional to the stroke volume. Signal processing techniques to identify J-waves in a subject having small amplitude was also developed based on the two common vectors at the head side and top.

Laser cleaning of steel for paint removal

NASA Astrophysics Data System (ADS)

Chen, G. X.; Kwee, T. J.; Tan, K. P.; Choo, Y. S.; Hong, M. H.

2010-11-01

Paint removal is an important part of steel processing for marine and offshore engineering. For centuries, a blasting techniques have been widely used for this surface preparation purpose. But conventional blasting always has intrinsic problems, such as noise, explosion risk, contaminant particles, vibration, and dust. In addition, processing wastes often cause environmental problems. In recent years, laser cleaning has attracted much research effort for its significant advantages, such as precise treatment, and high selectivity and flexibility in comparison with conventional cleaning techniques. In the present study, we use this environmentally friendly technique to overcome the problems of conventional blasting. Processed samples are examined with optical microscopes and other surface characterization tools. Experimental results show that laser cleaning can be a good alternative candidate to conventional blasting.

Strain gage measurement errors in the transient heating of structural components

NASA Technical Reports Server (NTRS)

Richards, W. Lance

1993-01-01

Significant strain-gage errors may exist in measurements acquired in transient thermal environments if conventional correction methods are applied. Conventional correction theory was modified and a new experimental method was developed to correct indicated strain data for errors created in radiant heating environments ranging from 0.6 C/sec (1 F/sec) to over 56 C/sec (100 F/sec). In some cases the new and conventional methods differed by as much as 30 percent. Experimental and analytical results were compared to demonstrate the new technique. For heating conditions greater than 6 C/sec (10 F/sec), the indicated strain data corrected with the developed technique compared much better to analysis than the same data corrected with the conventional technique.

Feasibility of ballistic strengthening exercises in neurologic rehabilitation.

PubMed

Williams, Gavin; Clark, Ross A; Hansson, Jessica; Paterson, Kade

2014-09-01

Conventional methods for strength training in neurologic rehabilitation are not task specific for walking. Ballistic strength training was developed to improve the functional transfer of strength training; however, no research has investigated this in neurologic populations. The aim of this pilot study was to evaluate the feasibility of applying ballistic principles to conventional leg strengthening exercises in individuals with mobility limitations as a result of neurologic injuries. Eleven individuals with neurologic injuries completed seated and reclined leg press using conventional and ballistic techniques. A 2 × 2 repeated-measures analysis of variance was used to compare power measures (peak movement height and peak velocity) between exercises and conditions. Peak jump velocity and peak jump height were greater when using the ballistic jump technique rather than the conventional concentric technique (P < 0.01). These findings suggest that when compared with conventional strengthening exercises, the incorporation of ballistic principles was associated with increased peak height and peak velocities.

Manufacturing implant supported auricular prostheses by rapid prototyping techniques.

PubMed

Karatas, Meltem Ozdemir; Cifter, Ebru Demet; Ozenen, Didem Ozdemir; Balik, Ali; Tuncer, Erman Bulent

2011-08-01

Maxillofacial prostheses are usually fabricated on the models obtained following the impression procedures. Disadvantages of conventional impression techniques used in production of facial prosthesis are deformation of soft tissues caused by impression material and disturbance of the patient due to. Additionally production of prosthesis by conventional methods takes longer time. Recently, rapid prototyping techniques have been developed for extraoral prosthesis in order to reduce these disadvantages of conventional methods. Rapid prototyping technique has the potential to simplify the procedure and decrease the laboratory work required. It eliminates the need for measurement impression procedures and preparation of wax model to be performed by prosthodontists themselves In the near future this technology will become a standard for fabricating maxillofacial prostheses.

Comparison of Kato-Katz, ethyl-acetate sedimentation, and Midi Parasep® in the diagnosis of hookworm, Ascaris and Trichuris infections in the context of an evaluation of rural sanitation in India.

PubMed

Funk, Anna L; Boisson, Sophie; Clasen, Thomas; Ensink, Jeroen H J

2013-06-01

The Kato-Katz, conventional ethyl-acetate sedimentation, and Midi Parasep(®) methods for diagnosing infection with soil-transmitted helminths were compared. The Kato-Katz technique gave the best overall diagnostic performance with the highest results in all measures (prevalence, faecal egg count, sensitivity) followed by the conventional ethyl-acetate and then the Midi Parasep(®) technique. The Kato-Katz technique showed a significantly higher faecal egg count and sensitivity for both hookworm and Trichuris as compared to the Midi Parasep(®) technique. The conventional ethyl-acetate technique produced smaller pellets and showed lower pellet mobility as compared to the Midi Parasep(®). Copyright © 2013 Elsevier B.V. All rights reserved.

Occlusal contact of fixed implant prostheses using functional bite impression technique.

PubMed

Suzuki, Yasunori; Shimpo, Hidemasa; Ohkubo, Chikahiro

2015-02-01

Functional bite impression (FBI) has been described as a definitive impression made under occlusal force after functional generated path (FGP) recording. This study compared the accuracy of occlusal contact of implant-fixed prostheses using the FBI technique and the conventional impression technique. Twelve subjects, each missing a single premolar or molar, were selected for this study. The conditions of the occlusal contacts were identified by the modified transillumination method. The occlusal contact condition was determined by comparing the rate of change in the occlusal contact area of the implant-fixed prostheses and both adjacent teeth before and after occlusal adjustment. The rate of change in the occlusal contact area using the FBI technique was 96%, and the rate using the conventional technique was 54%. The occlusal contact of implant prostheses using the FBI technique revealed better accuracy than that of the conventional technique. Regarding the FBI technique, a precise and functional prosthesis could be produced by completing the maxillomandibular registration, impression, and FGP at the same time.

SU-G-IeP2-06: Evaluation of Registration Accuracy for Cone-Beam CT Reconstruction Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, J; Wang, P; Zhang, H

2016-06-15

Purpose: Cone-beam (CB) computed tomography (CT) is used for image guidance during radiotherapy treatment delivery. Conventional Feldkamp and compressed sensing (CS) based CBCT recon-struction techniques are compared for image registration. This study is to evaluate the image registration accuracy of conventional and CS CBCT for head-and-neck (HN) patients. Methods: Ten HN patients with oropharyngeal tumors were retrospectively selected. Each HN patient had one planning CT (CTP) and three CBCTs were acquired during an adaptive radiotherapy proto-col. Each CBCT was reconstructed by both the conventional (CBCTCON) and compressed sens-ing (CBCTCS) methods. Two oncologists manually labeled 23 landmarks of normal tissue andmore » implanted gold markers on both the CTP and CBCTCON. Subsequently, landmarks on CTp were propagated to CBCTs, using a b-spline-based deformable image registration (DIR) and rigid registration (RR). The errors of these registration methods between two CBCT methods were calcu-lated. Results: For DIR, the mean distance between the propagated and the labeled landmarks was 2.8 mm ± 0.52 for CBCTCS, and 3.5 mm ± 0.75 for CBCTCON. For RR, the mean distance between the propagated and the labeled landmarks was 6.8 mm ± 0.92 for CBCTCS, and 8.7 mm ± 0.95 CBCTCON. Conclusion: This study has demonstrated that CS CBCT is more accurate than conventional CBCT in image registration by both rigid and non-rigid methods. It is potentially suggested that CS CBCT is an improved image modality for image guided adaptive applications.« less

Finite Element Modelling and Analysis of Conventional Pultrusion Processes

NASA Astrophysics Data System (ADS)

Akishin, P.; Barkanov, E.; Bondarchuk, A.

2015-11-01

Pultrusion is one of many composite manufacturing techniques and one of the most efficient methods for producing fiber reinforced polymer composite parts with a constant cross-section. Numerical simulation is helpful for understanding the manufacturing process and developing scientific means for the pultrusion tooling design. Numerical technique based on the finite element method has been developed for the simulation of pultrusion processes. It uses the general purpose finite element software ANSYS Mechanical. It is shown that the developed technique predicts the temperature and cure profiles, which are in good agreement with those published in the open literature.

Ultrathin Silicon Sheet in the Management of Unilateral Post-traumatic Temporo-Mandibuar Joint Ankylosis in Children: A Good Alternative to Conventional Techniques.

PubMed

Aggarwal, Sushil Kumar; Ankur, Bhatnagar; Jain, R K

2015-09-01

We have described a new technique of using ultra-thin silicon sheet (0.2 mm) between two transected bony ends for temporo-mandibular joint (TMJ) ankylosis in children with advantages of short operative time, minimal foreign material insertion and faster recovery time post-operatively which makes our technique a good alternative to conventional techniques. Our study is a non-randomized prospective study conducted on 10 children aged between 4 and 15 years who presented to our tertiary care institute with severe trismus after traumatic injury and were willing to undergo this new technique. The main outcome measure taken into consideration was difference between pre-operative, intra-operative (on table) and post-operative mouth opening (minimum 2 years follow-up). The pre-operative mouth opening in our cases varied from 1 to 5 mm. The intra-operative mouth opening achieved ranged from 2.8 to 3.2 cm. The mouth opening was about more than 2.7 cm in all our cases at 2 years of follow-up. Our technique is a good alternative to conventional techniques used for TMJ ankylosis in children but few more randomized controlled trials are required to assess its effectiveness in comparison to conventional techniques and for universal adoption of this technique.

New layer-based imaging and rapid prototyping techniques for computer-aided design and manufacture of custom dental restoration.

PubMed

Lee, M-Y; Chang, C-C; Ku, Y C

2008-01-01

Fixed dental restoration by conventional methods greatly relies on the skill and experience of the dental technician. The quality and accuracy of the final product depends mostly on the technician's subjective judgment. In addition, the traditional manual operation involves many complex procedures, and is a time-consuming and labour-intensive job. Most importantly, no quantitative design and manufacturing information is preserved for future retrieval. In this paper, a new device for scanning the dental profile and reconstructing 3D digital information of a dental model based on a layer-based imaging technique, called abrasive computer tomography (ACT) was designed in-house and proposed for the design of custom dental restoration. The fixed partial dental restoration was then produced by rapid prototyping (RP) and computer numerical control (CNC) machining methods based on the ACT scanned digital information. A force feedback sculptor (FreeForm system, Sensible Technologies, Inc., Cambridge MA, USA), which comprises 3D Touch technology, was applied to modify the morphology and design of the fixed dental restoration. In addition, a comparison of conventional manual operation and digital manufacture using both RP and CNC machining technologies for fixed dental restoration production is presented. Finally, a digital custom fixed restoration manufacturing protocol integrating proposed layer-based dental profile scanning, computer-aided design, 3D force feedback feature modification and advanced fixed restoration manufacturing techniques is illustrated. The proposed method provides solid evidence that computer-aided design and manufacturing technologies may become a new avenue for custom-made fixed restoration design, analysis, and production in the 21st century.

CNN: a speaker recognition system using a cascaded neural network.

PubMed

Zaki, M; Ghalwash, A; Elkouny, A A

1996-05-01

The main emphasis of this paper is to present an approach for combining supervised and unsupervised neural network models to the issue of speaker recognition. To enhance the overall operation and performance of recognition, the proposed strategy integrates the two techniques, forming one global model called the cascaded model. We first present a simple conventional technique based on the distance measured between a test vector and a reference vector for different speakers in the population. This particular distance metric has the property of weighting down the components in those directions along which the intraspeaker variance is large. The reason for presenting this method is to clarify the discrepancy in performance between the conventional and neural network approach. We then introduce the idea of using unsupervised learning technique, presented by the winner-take-all model, as a means of recognition. Due to several tests that have been conducted and in order to enhance the performance of this model, dealing with noisy patterns, we have preceded it with a supervised learning model--the pattern association model--which acts as a filtration stage. This work includes both the design and implementation of both conventional and neural network approaches to recognize the speakers templates--which are introduced to the system via a voice master card and preprocessed before extracting the features used in the recognition. The conclusion indicates that the system performance in case of neural network is better than that of the conventional one, achieving a smooth degradation in respect of noisy patterns, and higher performance in respect of noise-free patterns.

Artificial intelligence techniques used in respiratory sound analysis--a systematic review.

PubMed

Palaniappan, Rajkumar; Sundaraj, Kenneth; Sundaraj, Sebastian

2014-02-01

Artificial intelligence (AI) has recently been established as an alternative method to many conventional methods. The implementation of AI techniques for respiratory sound analysis can assist medical professionals in the diagnosis of lung pathologies. This article highlights the importance of AI techniques in the implementation of computer-based respiratory sound analysis. Articles on computer-based respiratory sound analysis using AI techniques were identified by searches conducted on various electronic resources, such as the IEEE, Springer, Elsevier, PubMed, and ACM digital library databases. Brief descriptions of the types of respiratory sounds and their respective characteristics are provided. We then analyzed each of the previous studies to determine the specific respiratory sounds/pathology analyzed, the number of subjects, the signal processing method used, the AI techniques used, and the performance of the AI technique used in the analysis of respiratory sounds. A detailed description of each of these studies is provided. In conclusion, this article provides recommendations for further advancements in respiratory sound analysis.

New optical frequency domain differential mode delay measurement method for a multimode optical fiber.

PubMed

Ahn, T; Moon, S; Youk, Y; Jung, Y; Oh, K; Kim, D

2005-05-30

A novel mode analysis method and differential mode delay (DMD) measurement technique for a multimode optical fiber based on optical frequency domain reflectometry has been proposed for the first time. We have used a conventional OFDR with a tunable external cavity laser and a Michelson interferometer. A few-mode optical multimode fiber was prepared to test our proposed measurement technique. We have also compared the OFDR measurement results with those obtained using a traditional time-domain measurement method.

Qualitative and quantitative detection of T7 bacteriophages using paper based sandwich ELISA.

PubMed

Khan, Mohidus Samad; Pande, Tripti; van de Ven, Theo G M

2015-08-01

Viruses cause many infectious diseases and consequently epidemic health threats. Paper based diagnostics and filters can offer attractive options for detecting and deactivating pathogens. However, due to their infectious characteristics, virus detection using paper diagnostics is more challenging compared to the detection of bacteria, enzymes, DNA or antigens. The major objective of this study was to prepare reliable, degradable and low cost paper diagnostics to detect viruses, without using sophisticated optical or microfluidic analytical instruments. T7 bacteriophage was used as a model virus. A paper based sandwich ELISA technique was developed to detect and quantify the T7 phages in solution. The paper based sandwich ELISA detected T7 phage concentrations as low as 100 pfu/mL to as high as 10(9) pfu/mL. The compatibility of paper based sandwich ELISA with the conventional titre count was tested using T7 phage solutions of unknown concentrations. The paper based sandwich ELISA technique is faster and economical compared to the traditional detection techniques. Therefore, with proper calibration and right reagents, and by following the biosafety regulations, the paper based technique can be said to be compatible and economical to the sophisticated laboratory diagnostic techniques applied to detect pathogenic viruses and other microorganisms. Copyright © 2015 Elsevier B.V. All rights reserved.

Nanosilica coating for bonding improvements to zirconia.

PubMed

Chen, Chen; Chen, Gang; Xie, Haifeng; Dai, Wenyong; Zhang, Feimin

2013-01-01

Resin bonding to zirconia cannot be established from standard methods that are currently utilized in conventional silica-based dental ceramics. The solution-gelatin (sol-gel) process is a well developed silica-coating technique used to modify the surface of nonsilica-based ceramics. Here, we use this technique to improve resin bonding to zirconia, which we compared to zirconia surfaces treated with alumina sandblasting and tribochemical silica coating. We used the shear bond strength test to examine the effect of the various coatings on the short-term resin bonding of zirconia. Furthermore, we employed field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier transform infrared spectroscopy to characterize the zirconia surfaces. Water-mist spraying was used to evaluate the durability of the coatings. To evaluate the biological safety of the experimental sol-gel silica coating, we conducted an in vitro Salmonella typhimurium reverse mutation assay (Ames mutagenicity test), cytotoxicity tests, and in vivo oral mucous membrane irritation tests. When compared to the conventional tribochemical silica coating, the experimental sol-gel silica coating provided the same shear bond strength, higher silicon contents, and better durability. Moreover, we observed no apparent mutagenicity, cytotoxicity, or irritation in this study. Therefore, the sol-gel technique represents a promising method for producing silica coatings on zirconia.

Analysis of Thick Sandwich Shells with Embedded Ceramic Tiles

NASA Technical Reports Server (NTRS)

Davila, Carlos G.; Smith, C.; Lumban-Tobing, F.

1996-01-01

The Composite Armored Vehicle (CAV) is an advanced technology demonstrator of an all-composite ground combat vehicle. The CAV upper hull is made of a tough light-weight S2-glass/epoxy laminate with embedded ceramic tiles that serve as armor. The tiles are bonded to a rubber mat with a carefully selected, highly viscoelastic adhesive. The integration of armor and structure offers an efficient combination of ballistic protection and structural performance. The analysis of this anisotropic construction, with its inherent discontinuous and periodic nature, however, poses several challenges. The present paper describes a shell-based 'element-layering' technique that properly accounts for these effects and for the concentrated transverse shear flexibility in the rubber mat. One of the most important advantages of the element-layering technique over advanced higher-order elements is that it is based on conventional elements. This advantage allows the models to be portable to other structural analysis codes, a prerequisite in a program that involves the computational facilities of several manufacturers and government laboratories. The element-layering technique was implemented into an auto-layering program that automatically transforms a conventional shell model into a multi-layered model. The effects of tile layer homogenization, tile placement patterns, and tile gap size on the analysis results are described.

Nanosilica coating for bonding improvements to zirconia

PubMed Central

Chen, Chen; Chen, Gang; Xie, Haifeng; Dai, Wenyong; Zhang, Feimin

2013-01-01

Resin bonding to zirconia cannot be established from standard methods that are currently utilized in conventional silica-based dental ceramics. The solution–gelatin (sol–gel) process is a well developed silica-coating technique used to modify the surface of nonsilica-based ceramics. Here, we use this technique to improve resin bonding to zirconia, which we compared to zirconia surfaces treated with alumina sandblasting and tribochemical silica coating. We used the shear bond strength test to examine the effect of the various coatings on the short-term resin bonding of zirconia. Furthermore, we employed field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier transform infrared spectroscopy to characterize the zirconia surfaces. Water–mist spraying was used to evaluate the durability of the coatings. To evaluate the biological safety of the experimental sol–gel silica coating, we conducted an in vitro Salmonella typhimurium reverse mutation assay (Ames mutagenicity test), cytotoxicity tests, and in vivo oral mucous membrane irritation tests. When compared to the conventional tribochemical silica coating, the experimental sol–gel silica coating provided the same shear bond strength, higher silicon contents, and better durability. Moreover, we observed no apparent mutagenicity, cytotoxicity, or irritation in this study. Therefore, the sol–gel technique represents a promising method for producing silica coatings on zirconia. PMID:24179333

Laser-based direct-write techniques for cell printing

PubMed Central

Schiele, Nathan R; Corr, David T; Huang, Yong; Raof, Nurazhani Abdul; Xie, Yubing; Chrisey, Douglas B

2016-01-01

Fabrication of cellular constructs with spatial control of cell location (±5 μm) is essential to the advancement of a wide range of applications including tissue engineering, stem cell and cancer research. Precise cell placement, especially of multiple cell types in co- or multi-cultures and in three dimensions, can enable research possibilities otherwise impossible, such as the cell-by-cell assembly of complex cellular constructs. Laser-based direct writing, a printing technique first utilized in electronics applications, has been adapted to transfer living cells and other biological materials (e.g., enzymes, proteins and bioceramics). Many different cell types have been printed using laser-based direct writing, and this technique offers significant improvements when compared to conventional cell patterning techniques. The predominance of work to date has not been in application of the technique, but rather focused on demonstrating the ability of direct writing to pattern living cells, in a spatially precise manner, while maintaining cellular viability. This paper reviews laser-based additive direct-write techniques for cell printing, and the various cell types successfully laser direct-written that have applications in tissue engineering, stem cell and cancer research are highlighted. A particular focus is paid to process dynamics modeling and process-induced cell injury during laser-based cell direct writing. PMID:20814088

Advances in Candida detection platforms for clinical and point-of-care applications

PubMed Central

Safavieh, Mohammadali; Coarsey, Chad; Esiobu, Nwadiuto; Memic, Adnan; Vyas, Jatin Mahesh; Shafiee, Hadi; Asghar, Waseem

2016-01-01

Invasive candidiasis remains one of the most serious community and healthcare-acquired infections worldwide. Conventional Candida detection methods based on blood and plate culture are time-consuming and require at least 2–4 days to identify various Candida species. Despite considerable advances for candidiasis detection, the development of simple, compact and portable point-of-care diagnostics for rapid and precise testing that automatically performs cell lysis, nucleic acid extraction, purification and detection still remains a challenge. Here, we systematically review most prominent conventional and nonconventional techniques for the detection of various Candida species, including Candida staining, blood culture, serological testing and nucleic acid-based analysis. We also discuss the most advanced lab on a chip devices for candida detection. PMID:27093473

Digital super-resolution holographic data storage based on Hermitian symmetry for achieving high areal density.

PubMed

Nobukawa, Teruyoshi; Nomura, Takanori

2017-01-23

Digital super-resolution holographic data storage based on Hermitian symmetry is proposed to store digital data in a tiny area of a medium. In general, reducing a recording area with an aperture leads to the improvement in the storage capacity of holographic data storage. Conventional holographic data storage systems however have a limitation in reducing a recording area. This limitation is called a Nyquist size. Unlike the conventional systems, our proposed system can overcome the limitation with the help of a digital holographic technique and digital signal processing. Experimental result shows that the proposed system can record and retrieve a hologram in a smaller area than the Nyquist size on the basis of Hermitian symmetry.

Comparison the Marginal and Internal Fit of Metal Copings Cast from Wax Patterns Fabricated by CAD/CAM and Conventional Wax up Techniques.

PubMed

Vojdani, M; Torabi, K; Farjood, E; Khaledi, Aar

2013-09-01

Metal-ceramic crowns are most commonly used as the complete coverage restorations in clinical daily use. Disadvantages of conventional hand-made wax-patterns introduce some alternative ways by means of CAD/CAM technologies. This study compares the marginal and internal fit of copings cast from CAD/CAM and conventional fabricated wax-patterns. Twenty-four standardized brass dies were prepared and randomly divided into 2 groups according to the wax-patterns fabrication method (CAD/CAM technique and conventional method) (n=12). All the wax-patterns were fabricated in a standard fashion by means of contour, thickness and internal relief (M1-M12: representative of CAD/CAM group, C1-C12: representative of conventional group). CAD/CAM milling machine (Cori TEC 340i; imes-icore GmbH, Eiterfeld, Germany) was used to fabricate the CAD/CAM group wax-patterns. The copings cast from 24 wax-patterns were cemented to the corresponding dies. For all the coping-die assemblies cross-sectional technique was used to evaluate the marginal and internal fit at 15 points. The Student's t- test was used for statistical analysis (α=0.05). The overall mean (SD) for absolute marginal discrepancy (AMD) was 254.46 (25.10) um for CAD/CAM group and 88.08(10.67) um for conventional group (control). The overall mean of internal gap total (IGT) was 110.77(5.92) um for CAD/CAM group and 76.90 (10.17) um for conventional group. The Student's t-test revealed significant differences between 2 groups. Marginal and internal gaps were found to be significantly higher at all measured areas in CAD/CAM group than conventional group (p< 0.001). Within limitations of this study, conventional method of wax-pattern fabrication produced copings with significantly better marginal and internal fit than CAD/CAM (machine-milled) technique. All the factors for 2 groups were standardized except wax pattern fabrication technique, therefore, only the conventional group results in copings with clinically acceptable margins of less than 120um.

Comparison the Marginal and Internal Fit of Metal Copings Cast from Wax Patterns Fabricated by CAD/CAM and Conventional Wax up Techniques

PubMed Central

Vojdani, M; Torabi, K; Farjood, E; Khaledi, AAR

2013-01-01

Statement of Problem: Metal-ceramic crowns are most commonly used as the complete coverage restorations in clinical daily use. Disadvantages of conventional hand-made wax-patterns introduce some alternative ways by means of CAD/CAM technologies. Purpose: This study compares the marginal and internal fit of copings cast from CAD/CAM and conventional fabricated wax-patterns. Materials and Method: Twenty-four standardized brass dies were prepared and randomly divided into 2 groups according to the wax-patterns fabrication method (CAD/CAM technique and conventional method) (n=12). All the wax-patterns were fabricated in a standard fashion by means of contour, thickness and internal relief (M1-M12: representative of CAD/CAM group, C1-C12: representative of conventional group). CAD/CAM milling machine (Cori TEC 340i; imes-icore GmbH, Eiterfeld, Germany) was used to fabricate the CAD/CAM group wax-patterns. The copings cast from 24 wax-patterns were cemented to the corresponding dies. For all the coping-die assemblies cross-sectional technique was used to evaluate the marginal and internal fit at 15 points. The Student’s t- test was used for statistical analysis (α=0.05). Results: The overall mean (SD) for absolute marginal discrepancy (AMD) was 254.46 (25.10) um for CAD/CAM group and 88.08(10.67) um for conventional group (control). The overall mean of internal gap total (IGT) was 110.77(5.92) um for CAD/CAM group and 76.90 (10.17) um for conventional group. The Student’s t-test revealed significant differences between 2 groups. Marginal and internal gaps were found to be significantly higher at all measured areas in CAD/CAM group than conventional group (p< 0.001). Conclusion: Within limitations of this study, conventional method of wax-pattern fabrication produced copings with significantly better marginal and internal fit than CAD/CAM (machine-milled) technique. All the factors for 2 groups were standardized except wax pattern fabrication technique, therefore, only the conventional group results in copings with clinically acceptable margins of less than 120um. PMID:24724133

Adaptation and micro-structure of Co-Cr alloy maxillary complete denture base plates fabricated by selective laser melting technique.

PubMed

Ye, Ye; Jiao, Ting; Zhu, Jiarui; Sun, Jian

2018-01-24

The purpose of the study was to evaluate the adaptation and micro-structure of Co-Cr alloy maxillary complete denture base plates fabricated by the selective laser melting (SLM) technique. Twenty pairs of edentulous casts were randomly and evenly divided into two groups, and manufacturing of the Co-Cr alloy maxillary complete denture base was conducted either by the SLM technique or by the conventional method. The base-cast sets were transversally sectioned into three sections at the distal canines, mesial of the first molars and the posterior palatal zone. The gap between the metal base and cast was measured in these three sections with a stereoscopic microscope, and the data were analysed using t tests. A total of five specimens of 5 mm diameter were fabricated with the Co-Cr alloy by SLM and the traditional casting technology. A scanning electron microscope (SEM) was used to evaluate the differences in microstructure between these specimens. There was no statistical difference between the three sections in all four groups (P > 0.05). At the region of the canines, the clearance value for the SLM Co-Cr alloy group was larger than that of the conventional method group (P < 0.05). At the mesial of the first molar region and the posterior palatal zone, there was no statistical difference between the gaps observed in the two groups (P > 0.05). The SLM Co-Cr alloy has a denser microstructure behaviour and less casting defect than the cast Co-Cr alloy. The SLM technique showed initial feasibility for the manufacture of dental bases of complete dentures, but large sample studies are needed to prove its reliability in clinical applications. The mechanical properties and microstructure of the denture frameworks prepared by selective laser melting indicate that these dentures are appropriate for clinical use.

Liposomal Bupivacaine Injection Technique in Total Knee Arthroplasty.

PubMed

Meneghini, R Michael; Bagsby, Deren; Ireland, Philip H; Ziemba-Davis, Mary; Lovro, Luke R

2017-01-01

Liposomal bupivacaine has gained popularity for pain control after total knee arthroplasty (TKA), yet its true efficacy remains unproven. We compared the efficacy of two different periarticular injection (PAI) techniques for liposomal bupivacaine with a conventional PAI control group. This retrospective cohort study compared consecutive patients undergoing TKA with a manufacturer-recommended, optimized injection technique for liposomal bupivacaine, a traditional injection technique for liposomal bupivacaine, and a conventional PAI of ropivacaine, morphine, and epinephrine. The optimized technique utilized a smaller gauge needle and more injection sites. Self-reported pain scores, rescue opioids, and side effects were compared. There were 41 patients in the liposomal bupivacaine optimized injection group, 60 in the liposomal bupivacaine traditional injection group, and 184 in the conventional PAI control group. PAI liposomal bupivacaine delivered via manufacturer-recommended technique offered no benefit over PAI ropivacaine, morphine, and epinephrine. Mean pain scores and the proportions reporting no or mild pain, time to first opioid, and amount of opioids consumed were not better with PAI liposomal bupivacaine compared with PAI ropivacaine, morphine, and epinephrine. The use of the manufacturer-recommended technique for PAI of liposomal bupivacaine does not offer benefit over a conventional, less expensive PAI during TKA. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

A hybrid algorithm for clustering of time series data based on affinity search technique.

PubMed

Aghabozorgi, Saeed; Ying Wah, Teh; Herawan, Tutut; Jalab, Hamid A; Shaygan, Mohammad Amin; Jalali, Alireza

2014-01-01

Time series clustering is an important solution to various problems in numerous fields of research, including business, medical science, and finance. However, conventional clustering algorithms are not practical for time series data because they are essentially designed for static data. This impracticality results in poor clustering accuracy in several systems. In this paper, a new hybrid clustering algorithm is proposed based on the similarity in shape of time series data. Time series data are first grouped as subclusters based on similarity in time. The subclusters are then merged using the k-Medoids algorithm based on similarity in shape. This model has two contributions: (1) it is more accurate than other conventional and hybrid approaches and (2) it determines the similarity in shape among time series data with a low complexity. To evaluate the accuracy of the proposed model, the model is tested extensively using syntactic and real-world time series datasets.

A Hybrid Algorithm for Clustering of Time Series Data Based on Affinity Search Technique

PubMed Central

Aghabozorgi, Saeed; Ying Wah, Teh; Herawan, Tutut; Jalab, Hamid A.; Shaygan, Mohammad Amin; Jalali, Alireza

2014-01-01

Time series clustering is an important solution to various problems in numerous fields of research, including business, medical science, and finance. However, conventional clustering algorithms are not practical for time series data because they are essentially designed for static data. This impracticality results in poor clustering accuracy in several systems. In this paper, a new hybrid clustering algorithm is proposed based on the similarity in shape of time series data. Time series data are first grouped as subclusters based on similarity in time. The subclusters are then merged using the k-Medoids algorithm based on similarity in shape. This model has two contributions: (1) it is more accurate than other conventional and hybrid approaches and (2) it determines the similarity in shape among time series data with a low complexity. To evaluate the accuracy of the proposed model, the model is tested extensively using syntactic and real-world time series datasets. PMID:24982966

TH-C-BRC-02: A Review of Emerging Technologies in Robotic SRS/SBRT Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, L.

The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioningmore » capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to deliver highly conformal radiosurgery treatments to multiple targets simultaneously via a single isocenter to replace the conventional multi-iso multi-plan treatments. It becomes important to understand the advantages and limitations of this technique, and the pitfalls for implementing this technique in clinical practice. The planning process of single-iso multi-target MAT will be described, and its plan quality and delivery efficiency will be compared with multi-iso plans. The QA process for verifying such complex plans will be illustrated, and pitfalls in imaging and patient set up will be discussed. Overall, this session will focus on the following areas: 1) Update on the emerging technology in current SRS/SBRT delivery. 2) New developments in treatment planning and Quality Assurance program. 3) Imaging guidance and motion management. Learning Objectives: To understand the SRS/SBRT principles and its clinical applications, and gain knowledge on the emerging technologies in SRS/SBRT. To review planning concepts and useful tips in treatment planning. To learn about the imaging guidance procedures and the quality assurance program in SRS/SBRT. National Institutes of Health, Varian Medical System; L. Ren, The presenter is funded by National Institutes of Health and Varian Medical System.« less

TH-C-BRC-01: An Overview of Emerging Technologies in SRS/SBRT Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, L.

2016-06-15

The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioningmore » capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to deliver highly conformal radiosurgery treatments to multiple targets simultaneously via a single isocenter to replace the conventional multi-iso multi-plan treatments. It becomes important to understand the advantages and limitations of this technique, and the pitfalls for implementing this technique in clinical practice. The planning process of single-iso multi-target MAT will be described, and its plan quality and delivery efficiency will be compared with multi-iso plans. The QA process for verifying such complex plans will be illustrated, and pitfalls in imaging and patient set up will be discussed. Overall, this session will focus on the following areas: 1) Update on the emerging technology in current SRS/SBRT delivery. 2) New developments in treatment planning and Quality Assurance program. 3) Imaging guidance and motion management. Learning Objectives: To understand the SRS/SBRT principles and its clinical applications, and gain knowledge on the emerging technologies in SRS/SBRT. To review planning concepts and useful tips in treatment planning. To learn about the imaging guidance procedures and the quality assurance program in SRS/SBRT. National Institutes of Health, Varian Medical System; L. Ren, The presenter is funded by National Institutes of Health and Varian Medical System.« less

TH-C-BRC-00: Emerging Technologies in SRS/SBRT Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2016-06-15

The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioningmore » capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to deliver highly conformal radiosurgery treatments to multiple targets simultaneously via a single isocenter to replace the conventional multi-iso multi-plan treatments. It becomes important to understand the advantages and limitations of this technique, and the pitfalls for implementing this technique in clinical practice. The planning process of single-iso multi-target MAT will be described, and its plan quality and delivery efficiency will be compared with multi-iso plans. The QA process for verifying such complex plans will be illustrated, and pitfalls in imaging and patient set up will be discussed. Overall, this session will focus on the following areas: 1) Update on the emerging technology in current SRS/SBRT delivery. 2) New developments in treatment planning and Quality Assurance program. 3) Imaging guidance and motion management. Learning Objectives: To understand the SRS/SBRT principles and its clinical applications, and gain knowledge on the emerging technologies in SRS/SBRT. To review planning concepts and useful tips in treatment planning. To learn about the imaging guidance procedures and the quality assurance program in SRS/SBRT. National Institutes of Health, Varian Medical System; L. Ren, The presenter is funded by National Institutes of Health and Varian Medical System.« less

Dimensional change in complete dentures fabricated by injection molding and microwave processing.

PubMed

Keenan, Phillip L J; Radford, David R; Clark, Robert K F

2003-01-01

Acrylic resin complete dentures undergo dimensional changes during polymerization. Techniques with injection molding and polymerization and microwave polymerization are reported to reduce these changes and thereby improve clinical fit. These dimensional changes need to be quantified. The purpose of this study was to compare differences in dimensional changes of simulated maxillary complete dentures during polymerization and storage in water after injection molding and conventional polymerization, or microwave polymerization against a control of conventionally packed and polymerized simulated maxillary complete dentures. Forty identical maxillary denture bases were prepared in dental wax with anatomic teeth. They were invested and the wax eliminated from the molds. Ten specimens each were randomly assigned to 1 of 4 groups. Group 1 was compression molded and conventionally polymerized; group 2 was injection molded and conventionally polymerized (Success); group 3 was injection molded and microwave polymerized (Acron MC); and group 4 was injection molded and microwave polymerized (Microbase). Intermolar width and changes in vertical dimension of occlusion, were determined after polymerization and after storage in water for 28 days. Measurements in triplicate were made between points scribed on the second molar teeth with a traveling microscope (accurate to 0.005 mm). Vertical dimension of occlusion was measured between points scribed on the upper and lower members of an articulator by use of an internal micrometer (accurate to 0.05 mm). Data were analyzed by use of a 1-way analysis of variance with Tukey post-hoc contrasts (P <.05). Polymerization contractions (intermolar widths) for each group were: group 1, -0.24%; group 2, -0.27%; group 3, -0.35%; and group 4, -0.37%. The Microbase specimens had greater shrinkage than conventionally polymerized specimens, but there were no significant differences between the groups. All injection methods had less postpolymerization increase in vertical dimension of occlusion (0.63 to 0.41 mm) than the conventional Trevalon control (0.74 mm), but only group 4 was significantly different (P<.004). After storage in water for 28 days, all specimens increased in vertical dimension of occlusion (0.10% to 0.16%) from polymerization techniques, but there were no significant differences between groups. Within the limitations of this study, injection molding resulted in a slightly less increase of vertical dimension of occlusion than conventional polymerization techniques, the difference being significant for Microbase compared with the conventional Trevalon control.

Identification of exhumed remains of fire tragedy victims using conventional methods and autosomal/Y-chromosomal short tandem repeat DNA profiling.

PubMed

Calacal, Gayvelline C; Delfin, Frederick C; Tan, Michelle Music M; Roewer, Lutz; Magtanong, Danilo L; Lara, Myra C; Fortun, Raquel dR; De Ungria, Maria Corazon A

2005-09-01

In a fire tragedy in Manila in December 1998, one of the worst tragic incidents which resulted in the reported death of 23 children, identity could not be established initially resulting in the burial of still unidentified bodies. Underscoring the importance of identifying each of the human remains, the bodies were exhumed 3 months after the tragedy. We describe here our work, which was the first national case handled by local laboratories wherein conventional and molecular-based techniques were successfully applied in forensic identification. The study reports analysis of DNA obtained from skeletal remains exposed to conditions of burning, burial, and exhumation. DNA typing methods using autosomal and Y-chromosomal short tandem repeat (Y-STR) markers reinforced postmortem examinations using conventional identification techniques. The strategy resulted in the identification of 18 out of the 21 human remains analyzed, overcoming challenges encountered due to the absence of established procedures for the recovery of mass disaster remains. There was incomplete antemortem information to match the postmortem data obtained from the remains of 3 female child victims. Two victims were readily identified due to the availability of antemortem tissues. In the absence of this biologic material, parentage testing was performed using reference blood samples collected from parents and relatives. Data on patrilineal lineage based on common Y-STR haplotypes augmented autosomal DNA typing, particularly in deficiency cases.

Comparison of Factorization-Based Filtering for Landing Navigation

NASA Technical Reports Server (NTRS)

McCabe, James S.; Brown, Aaron J.; DeMars, Kyle J.; Carson, John M., III

2017-01-01

This paper develops and analyzes methods for fusing inertial navigation data with external data, such as data obtained from an altimeter and a star camera. The particular filtering techniques are based upon factorized forms of the Kalman filter, specifically the UDU and Cholesky factorizations. The factorized Kalman filters are utilized to ensure numerical stability of the navigation solution. Simulations are carried out to compare the performance of the different approaches along a lunar descent trajectory using inertial and external data sources. It is found that the factorized forms improve upon conventional filtering techniques in terms of ensuring numerical stability for the investigated landing navigation scenario.

Calorimetric Measurement for Internal Conversion Efficiency of Photovoltaic Cells/Modules Based on Electrical Substitution Method

NASA Astrophysics Data System (ADS)

Saito, Terubumi; Tatsuta, Muneaki; Abe, Yamato; Takesawa, Minato

2018-02-01

We have succeeded in the direct measurement for solar cell/module internal conversion efficiency based on a calorimetric method or electrical substitution method by which the absorbed radiant power is determined by replacing the heat absorbed in the cell/module with the electrical power. The technique is advantageous in that the reflectance and transmittance measurements, which are required in the conventional methods, are not necessary. Also, the internal quantum efficiency can be derived from conversion efficiencies by using the average photon energy. Agreements of the measured data with the values estimated from the nominal values support the validity of this technique.

Applications of Support Vector Machines In Chemo And Bioinformatics

NASA Astrophysics Data System (ADS)

Jayaraman, V. K.; Sundararajan, V.

2010-10-01

Conventional linear & nonlinear tools for classification, regression & data driven modeling are being replaced on a rapid scale by newer techniques & tools based on artificial intelligence and machine learning. While the linear techniques are not applicable for inherently nonlinear problems, newer methods serve as attractive alternatives for solving real life problems. Support Vector Machine (SVM) classifiers are a set of universal feed-forward network based classification algorithms that have been formulated from statistical learning theory and structural risk minimization principle. SVM regression closely follows the classification methodology. In this work recent applications of SVM in Chemo & Bioinformatics will be described with suitable illustrative examples.

Fibre Optic Sensors for Selected Wastewater Characteristics

PubMed Central

Chong, Su Sin; Abdul Aziz, A. R.; Harun, Sulaiman W.

2013-01-01

Demand for online and real-time measurements techniques to meet environmental regulation and treatment compliance are increasing. However the conventional techniques, which involve scheduled sampling and chemical analysis can be expensive and time consuming. Therefore cheaper and faster alternatives to monitor wastewater characteristics are required as alternatives to conventional methods. This paper reviews existing conventional techniques and optical and fibre optic sensors to determine selected wastewater characteristics which are colour, Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). The review confirms that with appropriate configuration, calibration and fibre features the parameters can be determined with accuracy comparable to conventional method. With more research in this area, the potential for using FOS for online and real-time measurement of more wastewater parameters for various types of industrial effluent are promising. PMID:23881131

Gene-expression programming for flip-bucket spillway scour.

PubMed

Guven, Aytac; Azamathulla, H Md

2012-01-01

During the last two decades, researchers have noticed that the use of soft computing techniques as an alternative to conventional statistical methods based on controlled laboratory or field data, gave significantly better results. Gene-expression programming (GEP), which is an extension to genetic programming (GP), has nowadays attracted the attention of researchers in prediction of hydraulic data. This study presents GEP as an alternative tool in the prediction of scour downstream of a flip-bucket spillway. Actual field measurements were used to develop GEP models. The proposed GEP models are compared with the earlier conventional GP results of others (Azamathulla et al. 2008b; RMSE = 2.347, δ = 0.377, R = 0.842) and those of commonly used regression-based formulae. The predictions of GEP models were observed to be in strictly good agreement with measured ones, and quite a bit better than conventional GP and the regression-based formulae. The results are tabulated in terms of statistical error measures (GEP1; RMSE = 1.596, δ = 0.109, R = 0.917) and illustrated via scatter plots.

Input design for identification of aircraft stability and control derivatives

NASA Technical Reports Server (NTRS)

Gupta, N. K.; Hall, W. E., Jr.

1975-01-01

An approach for designing inputs to identify stability and control derivatives from flight test data is presented. This approach is based on finding inputs which provide the maximum possible accuracy of derivative estimates. Two techniques of input specification are implemented for this objective - a time domain technique and a frequency domain technique. The time domain technique gives the control input time history and can be used for any allowable duration of test maneuver, including those where data lengths can only be of short duration. The frequency domain technique specifies the input frequency spectrum, and is best applied for tests where extended data lengths, much longer than the time constants of the modes of interest, are possible. These technqiues are used to design inputs to identify parameters in longitudinal and lateral linear models of conventional aircraft. The constraints of aircraft response limits, such as on structural loads, are realized indirectly through a total energy constraint on the input. Tests with simulated data and theoretical predictions show that the new approaches give input signals which can provide more accurate parameter estimates than can conventional inputs of the same total energy. Results obtained indicate that the approach has been brought to the point where it should be used on flight tests for further evaluation.

Automatic transfer function generation for volume rendering of high-resolution x-ray 3D digital mammography images

NASA Astrophysics Data System (ADS)

Alyassin, Abdal M.

2002-05-01

3D Digital mammography (3DDM) is a new technology that provides high resolution X-ray breast tomographic data. Like any other tomographic medical imaging modalities, viewing a stack of tomographic images may require time especially if the images are of large matrix size. In addition, it may cause difficulty to conceptually construct 3D breast structures. Therefore, there is a need to readily visualize the data in 3D. However, one of the issues that hinder the usage of volume rendering (VR) is finding an automatic way to generate transfer functions that efficiently map the important diagnostic information in the data. We have developed a method that randomly samples the volume. Based on the mean and the standard deviation of these samples, the technique determines the lower limit and upper limit of a piecewise linear ramp transfer function. We have volume rendered several 3DDM data using this technique and compared visually the outcome with the result from a conventional automatic technique. The transfer function generated through the proposed technique provided superior VR images over the conventional technique. Furthermore, the improvement in the reproducibility of the transfer function correlated with the number of samples taken from the volume at the expense of the processing time.

New Researches and Application Progress of Commonly Used Optical Molecular Imaging Technology

PubMed Central

Chen, Zhi-Yi; Yang, Feng; Lin, Yan; Zhou, Qiu-Lan; Liao, Yang-Ying

2014-01-01

Optical molecular imaging, a new medical imaging technique, is developed based on genomics, proteomics and modern optical imaging technique, characterized by non-invasiveness, non-radiativity, high cost-effectiveness, high resolution, high sensitivity and simple operation in comparison with conventional imaging modalities. Currently, it has become one of the most widely used molecular imaging techniques and has been applied in gene expression regulation and activity detection, biological development and cytological detection, drug research and development, pathogenesis research, pharmaceutical effect evaluation and therapeutic effect evaluation, and so forth, This paper will review the latest researches and application progresses of commonly used optical molecular imaging techniques such as bioluminescence imaging and fluorescence molecular imaging. PMID:24696850

Keypoint Density-Based Region Proposal for Fine-Grained Object Detection and Classification Using Regions with Convolutional Neural Network Features

DTIC Science & Technology

2015-12-15

Keypoint Density-based Region Proposal for Fine-Grained Object Detection and Classification using Regions with Convolutional Neural Network ... Convolutional Neural Networks (CNNs) enable them to outperform conventional techniques on standard object detection and classification tasks, their...detection accuracy and speed on the fine-grained Caltech UCSD bird dataset (Wah et al., 2011). Recently, Convolutional Neural Networks (CNNs), a deep

TOPS On-Line: Automating the Construction and Maintenance of HTML Pages

NASA Technical Reports Server (NTRS)

Jones, Kennie H.

1994-01-01

After the Technology Opportunities Showcase (TOPS), in October, 1993, Langley Research Center's (LaRC) Information Systems Division (ISD) accepted the challenge to preserve the investment in information assembled in the TOPS exhibits by establishing a data base. Following the lead of several people at LaRC and others around the world, the HyperText Transport Protocol (HTTP) server and Mosaic were the obvious tools of choice for implementation. Initially, some TOPS exhibitors began the conventional approach of constructing HyperText Markup Language (HTML) pages of their exhibits as input to Mosaic. Considering the number of pages to construct, a better approach was conceived that would automate the construction of pages. This approach allowed completion of the data base construction in a shorter period of time using fewer resources than would have been possible with the conventional approach. It also provided flexibility for the maintenance and enhancement of the data base. Since that time, this approach has been used to automate construction of other HTML data bases. Through these experiences, it is concluded that the most effective use of the HTTP/Mosaic technology will require better tools and techniques for creating, maintaining and managing the HTML pages. The development and use of these tools and techniques are the subject of this document.

Design of a Physiology-Sensitive VR-Based Social Communication Platform for Children With Autism.

PubMed

Kuriakose, Selvia; Lahiri, Uttama

2017-08-01

Individuals with autism are often characterized by impairments in communication, reciprocal social interaction and explicit expression of their affective states. In conventional techniques, a therapist adjusts the intervention paradigm by monitoring the affective state e.g., anxiety of these individuals for effective floor-time-therapy. Conventional techniques, though powerful, are observation-based and face resource limitations. Technology-assisted systems can provide a quantitative, individualized rehabilitation platform. Presently-available systems are designed primarily to chain learning via aspects of one's performance alone restricting individualization. Specifically, these systems are not sensitive to one's anxiety. Our presented work seeks to bridge this gap by developing a novel VR-based interactive system with Anxiety-Sensitive adaptive technology. Specifically, such a system is capable of objectively identifying and quantifying one's anxiety level from real-time biomarkers, along with performance metrics. In turn it can adaptively respond in an individualized manner to foster improved social communication skills. In our present research, we have used Virtual Reality (VR) to design a proof-of-concept application that exposes participants to social tasks of varying challenges. Results of a preliminary usability study indicate the potential of our VR-based Anxiety-Sensitive system to foster improved task performance, thereby serving as a potent complementary tool in the hands of therapist.

Utilizing collagen membranes for guided tissue regeneration-based root coverage.

PubMed

Wang, Hom-Lay; Modarressi, Marmar; Fu, Jia-Hui

2012-06-01

Gingival recession is a common clinical problem that can result in hypersensitivity, pain, root caries and esthetic concerns. Conventional soft tissue procedures for root coverage require an additional surgical site, thereby causing additional trauma and donor site morbidity. In addition, the grafted tissues heal by repair, with formation of long junctional epithelium with some connective tissue attachment. Guided tissue regeneration-based root coverage was thus developed in an attempt to overcome these limitations while providing comparable clinical results. This paper addresses the biologic foundation of guided tissue regeneration-based root coverage, and describes the indications and contraindications for this technique, as well as the factors that influence outcomes. The step-by-step clinical techniques utilizing collagen membranes are also described. In comparison with conventional soft tissue procedures, the benefits of guided tissue regeneration-based root coverage procedures include new attachment formation, elimination of donor site morbidity, less chair-time, and unlimited availability and uniform thickness of the product. Collagen membranes, in particular, benefit from product biocompatibility with the host, while promoting chemotaxis, hemostasis, and exchange of gas and nutrients. Such characteristics lead to better wound healing by promoting primary wound coverage, angiogenesis, space creation and maintenance, and clot stability. In conclusion, collagen membranes are a reliable alternative for use in root coverage procedures. © 2012 John Wiley & Sons A/S.

Strain Induced Elastomer Buckling Instability for Mechanical Measurements (SIEBIMM)

NASA Astrophysics Data System (ADS)

Harrison, Christopher; Stafford, Christopher M.; Amis, Eric J.; Karim, Alamgir

2003-03-01

We introduce a new technique (SIEBIMM) for high-throughput measurements of the mechanical properties of thin polymeric films. This technique relies upon a highly periodic strain-induced buckling instability that arises from a mismatch of the moduli of a relatively stiff polymer coating on a soft silicone sheet. The modulus-dependent buckling wavelength, typically 1-10 microns for 100 nm thick glassy films, is rapidly measured by conventional light scattering. The SIEBIMM-measured modulus is shown to agree with that measured by conventional Instron-like techniques. We directly show that the buckling instability is highly sinusoidal at low strain thereby insuring the suitability of simple mechanical analysis. Utilizing our expertise in preparing thickness gradients via flow coating, we demonstrate that the flexural rigidities of thin films having a wide range of thicknesses can be measured in minutes. By measuring the temporal decay of strain-induced diffraction peaks for plasticized coatings we show that this technique can evaluate viscoelastic properties, such as creep. We demonstrate SIEBIMM's capability with several academic and industrially-relevant polymeric systems, including polystyrene loaded with a wide range of plasticizer, a blend of block copolymers with polystyrene and polyisoprene blocks (Vector 4215 and 4411), and a thiolene-based ultraviolet curing adhesive.

Manufacturing Implant Supported Auricular Prostheses by Rapid Prototyping Techniques

PubMed Central

Karatas, Meltem Ozdemir; Cifter, Ebru Demet; Ozenen, Didem Ozdemir; Balik, Ali; Tuncer, Erman Bulent

2011-01-01

Maxillofacial prostheses are usually fabricated on the models obtained following the impression procedures. Disadvantages of conventional impression techniques used in production of facial prosthesis are deformation of soft tissues caused by impression material and disturbance of the patient due to. Additionally production of prosthesis by conventional methods takes longer time. Recently, rapid prototyping techniques have been developed for extraoral prosthesis in order to reduce these disadvantages of conventional methods. Rapid prototyping technique has the potential to simplify the procedure and decrease the laboratory work required. It eliminates the need for measurement impression procedures and preparation of wax model to be performed by prosthodontists themselves In the near future this technology will become a standard for fabricating maxillofacial prostheses. PMID:21912504

WE-EF-207-01: FEATURED PRESENTATION and BEST IN PHYSICS (IMAGING): Task-Driven Imaging for Cone-Beam CT in Interventional Guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gang, G; Stayman, J; Ouadah, S

2015-06-15

Purpose: This work introduces a task-driven imaging framework that utilizes a patient-specific anatomical model, mathematical definition of the imaging task, and a model of the imaging system to prospectively design acquisition and reconstruction techniques that maximize task-based imaging performance. Utility of the framework is demonstrated in the joint optimization of tube current modulation and view-dependent reconstruction kernel in filtered-backprojection reconstruction and non-circular orbit design in model-based reconstruction. Methods: The system model is based on a cascaded systems analysis of cone-beam CT capable of predicting the spatially varying noise and resolution characteristics as a function of the anatomical model and amore » wide range of imaging parameters. Detectability index for a non-prewhitening observer model is used as the objective function in a task-driven optimization. The combination of tube current and reconstruction kernel modulation profiles were identified through an alternating optimization algorithm where tube current was updated analytically followed by a gradient-based optimization of reconstruction kernel. The non-circular orbit is first parameterized as a linear combination of bases functions and the coefficients were then optimized using an evolutionary algorithm. The task-driven strategy was compared with conventional acquisitions without modulation, using automatic exposure control, and in a circular orbit. Results: The task-driven strategy outperformed conventional techniques in all tasks investigated, improving the detectability of a spherical lesion detection task by an average of 50% in the interior of a pelvis phantom. The non-circular orbit design successfully mitigated photon starvation effects arising from a dense embolization coil in a head phantom, improving the conspicuity of an intracranial hemorrhage proximal to the coil. Conclusion: The task-driven imaging framework leverages a knowledge of the imaging task within a patient-specific anatomical model to optimize image acquisition and reconstruction techniques, thereby improving imaging performance beyond that achievable with conventional approaches. 2R01-CA-112163; R01-EB-017226; U01-EB-018758; Siemens Healthcare (Forcheim, Germany)« less

Conventional and Advanced Separations in Mass Spectrometry-Based Metabolomics: Methodologies and Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heyman, Heino M.; Zhang, Xing; Tang, Keqi

2016-02-16

Metabolomics is the quantitative analysis of all metabolites in a given sample. Due to the chemical complexity of the metabolome, optimal separations are required for comprehensive identification and quantification of sample constituents. This chapter provides an overview of both conventional and advanced separations methods in practice for reducing the complexity of metabolite extracts delivered to the mass spectrometer detector, and covers gas chromatography (GC), liquid chromatography (LC), capillary electrophoresis (CE), supercritical fluid chromatography (SFC) and ion mobility spectrometry (IMS) separation techniques coupled with mass spectrometry (MS) as both uni-dimensional and as multi-dimensional approaches.

A Corpus-Based Approach for Automatic Thai Unknown Word Recognition Using Boosting Techniques

NASA Astrophysics Data System (ADS)

Techo, Jakkrit; Nattee, Cholwich; Theeramunkong, Thanaruk

While classification techniques can be applied for automatic unknown word recognition in a language without word boundary, it faces with the problem of unbalanced datasets where the number of positive unknown word candidates is dominantly smaller than that of negative candidates. To solve this problem, this paper presents a corpus-based approach that introduces a so-called group-based ranking evaluation technique into ensemble learning in order to generate a sequence of classification models that later collaborate to select the most probable unknown word from multiple candidates. Given a classification model, the group-based ranking evaluation (GRE) is applied to construct a training dataset for learning the succeeding model, by weighing each of its candidates according to their ranks and correctness when the candidates of an unknown word are considered as one group. A number of experiments have been conducted on a large Thai medical text to evaluate performance of the proposed group-based ranking evaluation approach, namely V-GRE, compared to the conventional naïve Bayes classifier and our vanilla version without ensemble learning. As the result, the proposed method achieves an accuracy of 90.93±0.50% when the first rank is selected while it gains 97.26±0.26% when the top-ten candidates are considered, that is 8.45% and 6.79% improvement over the conventional record-based naïve Bayes classifier and the vanilla version. Another result on applying only best features show 93.93±0.22% and up to 98.85±0.15% accuracy for top-1 and top-10, respectively. They are 3.97% and 9.78% improvement over naive Bayes and the vanilla version. Finally, an error analysis is given.

Directed Student Inquiry: Modeling in Roborovsky Hamsters

ERIC Educational Resources Information Center

Elwess, Nancy L.; Bouchard, Adam

2007-01-01

In this inquiry-based activity, Roborovsky hamsters are used to provide students with an opportunity to develop their skills of analysis, inquiry, and design. These hamsters are easy to maintain, yet offer students a means to use conventional techniques and those of their own design to make further observations through measuring, assessing, and…

Screening and rapid identification of Campylobacter spp. DNA by FlaA PCR based method on chicken and human fecal samples in Egypt

USDA-ARS?s Scientific Manuscript database

Campylobacter is a foodborne pathogen which has a potential public health concern worldwide. Due to discriminatory problems encountered by conventional isolation of Campylobacter spp. and its genetic similarities, rapid molecular techniques for its genetic characterization are useful. In this study,...

Immunodetection of T-2 Metabolites in Rat Urines after Dermal, Oral, or Intramuscular Exposure to T-2 Toxin

DTIC Science & Technology

1988-07-25

laboratory studies, but not useful for evaluation of natural exposure. Several conventional immunoassay techniques based on tritiated ligands (Fontelo. et...1978. Natural occurrence of trichothecenes (nivaienol, deoxynivalenol, T-2) and zearalenone in corn. ExperiLentia 34, 1333-1334. LEE. S. and CHU, F.S

Detection limits and cost comparisons of human- and gull-associated conventional and quantitative PCR assays in artificial and environmental waters

EPA Science Inventory

Modern techniques for tracking fecal pollution in environmental waters require investing in DNA-based methods to determine the presence of specific fecal sources. To help water quality managers decide whether to employ routine polymerase chain reaction (PCR) or quantitative PC...

The "Spread" of Merit-Based College Aid: Politics, Policy Consortia, and Interstate Competition

ERIC Educational Resources Information Center

Cohen-Vogel, Lora; Ingle, William Kyle; Levine, Amy Albee; Spence, Matthew

2008-01-01

Many political scientists maintain that public policies diffuse across states and that proximate states, in particular, influence one another's policy activities. Using state-funded merit aid for college as its case, this article takes a new approach to the study of the diffusion phenomenon, leaving behind conventional techniques used by…

A review on recent contribution of meshfree methods to structure and fracture mechanics applications.

PubMed

Daxini, S D; Prajapati, J M

2014-01-01

Meshfree methods are viewed as next generation computational techniques. With evident limitations of conventional grid based methods, like FEM, in dealing with problems of fracture mechanics, large deformation, and simulation of manufacturing processes, meshfree methods have gained much attention by researchers. A number of meshfree methods have been proposed till now for analyzing complex problems in various fields of engineering. Present work attempts to review recent developments and some earlier applications of well-known meshfree methods like EFG and MLPG to various types of structure mechanics and fracture mechanics applications like bending, buckling, free vibration analysis, sensitivity analysis and topology optimization, single and mixed mode crack problems, fatigue crack growth, and dynamic crack analysis and some typical applications like vibration of cracked structures, thermoelastic crack problems, and failure transition in impact problems. Due to complex nature of meshfree shape functions and evaluation of integrals in domain, meshless methods are computationally expensive as compared to conventional mesh based methods. Some improved versions of original meshfree methods and other techniques suggested by researchers to improve computational efficiency of meshfree methods are also reviewed here.

Design of a Programmable Gain, Temperature Compensated Current-Input Current-Output CMOS Logarithmic Amplifier.

PubMed

Ming Gu; Chakrabartty, Shantanu

2014-06-01

This paper presents the design of a programmable gain, temperature compensated, current-mode CMOS logarithmic amplifier that can be used for biomedical signal processing. Unlike conventional logarithmic amplifiers that use a transimpedance technique to generate a voltage signal as a logarithmic function of the input current, the proposed approach directly produces a current output as a logarithmic function of the input current. Also, unlike a conventional transimpedance amplifier the gain of the proposed logarithmic amplifier can be programmed using floating-gate trimming circuits. The synthesis of the proposed circuit is based on the Hart's extended translinear principle which involves embedding a floating-voltage source and a linear resistive element within a translinear loop. Temperature compensation is then achieved using a translinear-based resistive cancelation technique. Measured results from prototypes fabricated in a 0.5 μm CMOS process show that the amplifier has an input dynamic range of 120 dB and a temperature sensitivity of 230 ppm/°C (27 °C- 57°C), while consuming less than 100 nW of power.

Formation mechanisms of boron oxide films fabricated by large-area electron beam-induced deposition of trimethyl borate

PubMed Central

Depond, Philip J

2018-01-01

Boron-containing materials are increasingly drawing interest for the use in electronics, optics, laser targets, neutron absorbers, and high-temperature and chemically resistant ceramics. In this article, the first investigation into the deposition of boron-based material via electron beam-induced deposition (EBID) is reported. Thin films were deposited using a novel, large-area EBID system that is shown to deposit material at rates comparable to conventional techniques such as laser-induced chemical vapor deposition. The deposition rate and stoichiometry of boron oxide fabricated by EBID using trimethyl borate (TMB) as precursor is found to be critically dependent on the substrate temperature. By comparing the deposition mechanisms of TMB to the conventional, alkoxide-based precursor tetraethyl orthosilicate it is revealed that ligand chemistry does not precisely predict the pathways leading to deposition of material via EBID. The results demonstrate the first boron-containing material deposited by the EBID process and the potential for EBID as a scalable fabrication technique that could have a transformative effect on the athermal deposition of materials. PMID:29765806

Formation mechanisms of boron oxide films fabricated by large-area electron beam-induced deposition of trimethyl borate.

PubMed

Martin, Aiden A; Depond, Philip J

2018-01-01

Boron-containing materials are increasingly drawing interest for the use in electronics, optics, laser targets, neutron absorbers, and high-temperature and chemically resistant ceramics. In this article, the first investigation into the deposition of boron-based material via electron beam-induced deposition (EBID) is reported. Thin films were deposited using a novel, large-area EBID system that is shown to deposit material at rates comparable to conventional techniques such as laser-induced chemical vapor deposition. The deposition rate and stoichiometry of boron oxide fabricated by EBID using trimethyl borate (TMB) as precursor is found to be critically dependent on the substrate temperature. By comparing the deposition mechanisms of TMB to the conventional, alkoxide-based precursor tetraethyl orthosilicate it is revealed that ligand chemistry does not precisely predict the pathways leading to deposition of material via EBID. The results demonstrate the first boron-containing material deposited by the EBID process and the potential for EBID as a scalable fabrication technique that could have a transformative effect on the athermal deposition of materials.

Study of support vector machine and serum surface-enhanced Raman spectroscopy for noninvasive esophageal cancer detection

NASA Astrophysics Data System (ADS)

Li, Shao-Xin; Zeng, Qiu-Yao; Li, Lin-Fang; Zhang, Yan-Jiao; Wan, Ming-Ming; Liu, Zhi-Ming; Xiong, Hong-Lian; Guo, Zhou-Yi; Liu, Song-Hao

2013-02-01

The ability of combining serum surface-enhanced Raman spectroscopy (SERS) with support vector machine (SVM) for improving classification esophageal cancer patients from normal volunteers is investigated. Two groups of serum SERS spectra based on silver nanoparticles (AgNPs) are obtained: one group from patients with pathologically confirmed esophageal cancer (n=30) and the other group from healthy volunteers (n=31). Principal components analysis (PCA), conventional SVM (C-SVM) and conventional SVM combination with PCA (PCA-SVM) methods are implemented to classify the same spectral dataset. Results show that a diagnostic accuracy of 77.0% is acquired for PCA technique, while diagnostic accuracies of 83.6% and 85.2% are obtained for C-SVM and PCA-SVM methods based on radial basis functions (RBF) models. The results prove that RBF SVM models are superior to PCA algorithm in classification serum SERS spectra. The study demonstrates that serum SERS in combination with SVM technique has great potential to provide an effective and accurate diagnostic schema for noninvasive detection of esophageal cancer.

Advances in Laser Microprobe (U-Th)/He Geochronology

NASA Astrophysics Data System (ADS)

van Soest, M. C.; Monteleone, B. D.; Boyce, J. W.; Hodges, K. V.

2008-12-01

The development of the laser microprobe (U-Th)/He dating method has the potential to overcome many of the limitations that affect conventional (U-Th)/He geochronology. Conventional single- or multi-crystal (U- Th)/He geochronology requires the use of pristine, inclusion-free, euhedral crystals. Furthermore, the ages that are obtained require corrections for the effects of zoning and alpha ejection based on an ensemble of assumptions before interpretation of their geological relevance is possible. With the utilization of microbeam techniques many of the limitations of conventional (U-Th)/He geochronology can either be eliminated by careful spot selection or accounted for by detailed depth profiling analyses of He, U and Th on the same crystal. Combined He, Th, and U depth profiling on the same crystal potentially even offers the ability to extract thermal histories from the analyzed grains. Boyce et al. (2006) first demonstrated the laser microprobe (U-Th)/He dating technique by successfully dating monazite crystals using UV laser ablation to liberate He and determined U and Th concentrations using a Cameca SX-Ultrachron microprobe. At Arizona State University, further development of the microprobe (U-Th)/He dating technique continues using an ArF Excimer laser connected to a GVI Helix Split Flight Tube noble gas mass spectrometer for He analysis and SIMS techniques for U and Th. The Durango apatite age standard has been successfully dated at 30.7 +/- 1.7 Ma (2SD). Work on dating zircons by laser ablation is currently underway, with initial results from Sri Lanka zircon at 437 +/- 14 Ma (2SD) confirmed by conventional (U-Th)/He analysis and in agreement with the published (U-Th)/He age of 443 +/- 9 Ma (2SD) for zircons from this region in Sri Lanka (Nasdala et al., 2004). The results presented here demonstrate the laser microprobe (U-Th)/He method as a powerful tool that allows application of (U- Th)/He dating to areas of research such as detrital apatite and zircon dating, where conventional (U-Th)/He geochronology has limited applicability. Boyce et al. (2006) GCA 70 (3031-3039), Nasdala et al. (2004) Am. Min. 89 (219-231)

Effect of shoulder abduction angle on biomechanical properties of the repaired rotator cuff tendons with 3 types of double-row technique.

PubMed

Mihata, Teruhisa; Fukuhara, Tetsutaro; Jun, Bong Jae; Watanabe, Chisato; Kinoshita, Mitsuo

2011-03-01

After rotator cuff repair, the shoulder is immobilized in various abduction positions. However, there is no consensus on the proper abduction angle. To assess the effect of shoulder abduction angle on the biomechanical properties of the repaired rotator cuff tendons among 3 types of double-row techniques. Controlled laboratory study. Thirty-two fresh-frozen porcine shoulders were used. A simulated rotator cuff tear was repaired by 1 of 3 double-row techniques: conventional double-row repair, transosseous-equivalent repair, and a combination of conventional double-row and bridging sutures (compression double-row repair). Each specimen underwent cyclic testing followed by tensile testing to failure at a simulated shoulder abduction angle of 0° or 40° on a material testing machine. Gap formation and failure loads were measured. Gap formation in conventional double-row repair at 0° (1.2 ± 0.5 mm) was significantly greater than that at 40° (0.5 ± 0.3mm, P = .01). The yield and ultimate failure loads for conventional double-row repair at 40° were significantly larger than those at 0° (P < .01), whereas those for transosseous-equivalent repair (P < .01) and compression double-row repair (P < .0001) at 0° were significantly larger than those at 40°. The failure load for compression double-row repair was the greatest among the 3 double-row techniques at both 0° and 40° of abduction. Bridging sutures have a greater effect on the biomechanical properties of the repaired rotator cuff tendon at a low abduction angle, and the conventional double-row technique has a greater effect at a high abduction angle. Proper abduction position after rotator cuff repair differs between conventional double-row repair and transosseous-equivalent repair. The authors recommend the use of the combined technique of conventional double-row and bridging sutures to obtain better biomechanical properties at both low and high abduction angles.

Improvement of attenuation correction in time-of-flight PET/MR imaging with a positron-emitting source.

PubMed

Mollet, Pieter; Keereman, Vincent; Bini, Jason; Izquierdo-Garcia, David; Fayad, Zahi A; Vandenberghe, Stefaan

2014-02-01

Quantitative PET imaging relies on accurate attenuation correction. Recently, there has been growing interest in combining state-of-the-art PET systems with MR imaging in a sequential or fully integrated setup. As CT becomes unavailable for these systems, an alternative approach to the CT-based reconstruction of attenuation coefficients (μ values) at 511 keV must be found. Deriving μ values directly from MR images is difficult because MR signals are related to the proton density and relaxation properties of tissue. Therefore, most research groups focus on segmentation or atlas registration techniques. Although studies have shown that these methods provide viable solutions in particular applications, some major drawbacks limit their use in whole-body PET/MR. Previously, we used an annulus-shaped PET transmission source inside the field of view of a PET scanner to measure attenuation coefficients at 511 keV. In this work, we describe the use of this method in studies of patients with the sequential time-of-flight (TOF) PET/MR scanner installed at the Icahn School of Medicine at Mount Sinai, New York, NY. Five human PET/MR and CT datasets were acquired. The transmission-based attenuation correction method was compared with conventional CT-based attenuation correction and the 3-segment, MR-based attenuation correction available on the TOF PET/MR imaging scanner. The transmission-based method overcame most problems related to the MR-based technique, such as truncation artifacts of the arms, segmentation artifacts in the lungs, and imaging of cortical bone. Additionally, the TOF capabilities of the PET detectors allowed the simultaneous acquisition of transmission and emission data. Compared with the MR-based approach, the transmission-based method provided average improvements in PET quantification of 6.4%, 2.4%, and 18.7% in volumes of interest inside the lung, soft tissue, and bone tissue, respectively. In conclusion, a transmission-based technique with an annulus-shaped transmission source will be more accurate than a conventional MR-based technique for measuring attenuation coefficients at 511 keV in future whole-body PET/MR studies.

Feasibility of new breeding techniques for organic farming.

PubMed

Andersen, Martin Marchman; Landes, Xavier; Xiang, Wen; Anyshchenko, Artem; Falhof, Janus; Østerberg, Jeppe Thulin; Olsen, Lene Irene; Edenbrandt, Anna Kristina; Vedel, Suzanne Elizabeth; Thorsen, Bo Jellesmark; Sandøe, Peter; Gamborg, Christian; Kappel, Klemens; Palmgren, Michael G

2015-07-01

Organic farming is based on the concept of working 'with nature' instead of against it; however, compared with conventional farming, organic farming reportedly has lower productivity. Ideally, the goal should be to narrow this yield gap. In this review, we specifically discuss the feasibility of new breeding techniques (NBTs) for rewilding, a process involving the reintroduction of properties from the wild relatives of crops, as a method to close the productivity gap. The most efficient methods of rewilding are based on modern biotechnology techniques, which have yet to be embraced by the organic farming movement. Thus, the question arises of whether the adoption of such methods is feasible, not only from a technological perspective, but also from conceptual, socioeconomic, ethical, and regulatory perspectives. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multispectral Wavefronts Retrieval in Digital Holographic Three-Dimensional Imaging Spectrometry

NASA Astrophysics Data System (ADS)

Yoshimori, Kyu

2010-04-01

This paper deals with a recently developed passive interferometric technique for retrieving a set of spectral components of wavefronts that are propagating from a spatially incoherent, polychromatic object. The technique is based on measurement of 5-D spatial coherence function using a suitably designed interferometer. By applying signal processing, including aperture synthesis and spectral decomposition, one may obtains a set of wavefronts of different spectral bands. Since each wavefront is equivalent to the complex Fresnel hologram at a particular spectrum of the polychromatic object, application of the conventional Fresnel transform yields 3-D image of different spectrum. Thus, this technique of multispectral wavefronts retrieval provides a new type of 3-D imaging spectrometry based on a fully passive interferometry. Experimental results are also shown to demonstrate the validity of the method.

Comparison of Artificial Immune System and Particle Swarm Optimization Techniques for Error Optimization of Machine Vision Based Tool Movements

NASA Astrophysics Data System (ADS)

Mahapatra, Prasant Kumar; Sethi, Spardha; Kumar, Amod

2015-10-01

In conventional tool positioning technique, sensors embedded in the motion stages provide the accurate tool position information. In this paper, a machine vision based system and image processing technique for motion measurement of lathe tool from two-dimensional sequential images captured using charge coupled device camera having a resolution of 250 microns has been described. An algorithm was developed to calculate the observed distance travelled by the tool from the captured images. As expected, error was observed in the value of the distance traversed by the tool calculated from these images. Optimization of errors due to machine vision system, calibration, environmental factors, etc. in lathe tool movement was carried out using two soft computing techniques, namely, artificial immune system (AIS) and particle swarm optimization (PSO). The results show better capability of AIS over PSO.

Femoral graft-tunnel angles in posterior cruciate ligament reconstruction: analysis with 3-dimensional models and cadaveric experiments.

PubMed

Kim, Sung-Jae; Chun, Yong-Min; Kim, Sung-Hwan; Moon, Hong-Kyo; Jang, Jae-Won

2013-07-01

The purpose of this study was to compare four graft-tunnel angles (GTA), the femoral GTA formed by three different femoral tunneling techniques (the outside-in, a modified inside-out technique in the posterior sag position with knee hyperflexion, and the conventional inside-out technique) and the tibia GTA in 3-dimensional (3D) knee flexion models, as well as to examine the influence of femoral tunneling techniques on the contact pressure between the intra-articular aperture of the femoral tunnel and the graft. Twelve cadaveric knees were tested. Computed tomography scans were performed at different knee flexion angles (0°, 45°, 90°, and 120°). Femoral and tibial GTAs were measured at different knee flexion angles on the 3D knee models. Using pressure sensitive films, stress on the graft of the angulation of the femoral tunnel aperture was measured in posterior cruciate ligament reconstructed cadaveric knees. Between 45° and 120° of knee flexion, there were no significant differences between the outside-in and modified inside-out techniques. However, the femoral GTA for the conventional inside-out technique was significantly less than that for the other two techniques (p<0.001). In cadaveric experiments using pressure-sensitive film, the maximum contact pressure for the modified inside-out and outside-in technique was significantly lower than that for the conventional inside-out technique (p=0.024 and p=0.017). The conventional inside-out technique results in a significantly lesser GTA and higher stress at the intra-articular aperture of the femoral tunnel than the outside-in technique. However, the results for the modified inside-out technique are similar to those for the outside-in technique.

Applications of Advanced, Waveform Based AE Techniques for Testing Composite Materials

NASA Technical Reports Server (NTRS)

Prosser, William H.

1996-01-01

Advanced, waveform based acoustic emission (AE) techniques have been previously used to evaluate damage progression in laboratory tests of composite coupons. In these tests, broad band, high fidelity acoustic sensors were used to detect signals which were then digitized and stored for analysis. Analysis techniques were based on plate mode wave propagation characteristics. This approach, more recently referred to as Modal AE, provides an enhanced capability to discriminate and eliminate noise signals from those generated by damage mechanisms. This technique also allows much more precise source location than conventional, threshold crossing arrival time determination techniques. To apply Modal AE concepts to the interpretation of AE on larger composite structures, the effects of wave propagation over larger distances and through structural complexities must be well characterized and understood. In this research, measurements were made of the attenuation of the extensional and flexural plate mode components of broad band simulated AE signals in large composite panels. As these materials have applications in a cryogenic environment, the effects of cryogenic insulation on the attenuation of plate mode AE signals were also documented.

Monitoring of pipelines in nuclear power plants by measuring laser-based mechanical impedance

NASA Astrophysics Data System (ADS)

Lee, Hyeonseok; Sohn, Hoon; Yang, Suyoung; Yang, Jinyeol

2014-06-01

Using laser-based mechanical impedance (LMI) measurement, this study proposes a damage detection technique that enables structural health monitoring of pipelines under the high temperature and radioactive environments of nuclear power plants (NPPs). The applications of conventional electromechanical impedance (EMI) based techniques to NPPs have been limited, mainly due to the contact nature of piezoelectric transducers, which cannot survive under the high temperature and high radiation environments of NPPs. The proposed LMI measurement technique aims to tackle the limitations of the EMI techniques by utilizing noncontact laser beams for both ultrasound generation and sensing. An Nd:Yag pulse laser is used for ultrasound generation, and a laser Doppler vibrometer is employed for the measurement of the corresponding ultrasound responses. For the monitoring of pipes covered by insulation layers, this study utilizes optical fibers to guide the laser beams to specific target locations. Then, an outlier analysis is adopted for autonomous damage diagnosis. Validation of the proposed LMI technique is carried out on a carbon steel pipe elbow under varying temperatures. A corrosion defect chemically engraved in the specimen is successfully detected.

Translation of Atherosclerotic Plaque Phase-Contrast CT Imaging from Synchrotron Radiation to a Conventional Lab-Based X-Ray Source

PubMed Central

Saam, Tobias; Herzen, Julia; Hetterich, Holger; Fill, Sandra; Willner, Marian; Stockmar, Marco; Achterhold, Klaus; Zanette, Irene; Weitkamp, Timm; Schüller, Ulrich; Auweter, Sigrid; Adam-Neumair, Silvia; Nikolaou, Konstantin; Reiser, Maximilian F.; Pfeiffer, Franz; Bamberg, Fabian

2013-01-01

Objectives Phase-contrast imaging is a novel X-ray based technique that provides enhanced soft tissue contrast. The aim of this study was to evaluate the feasibility of visualizing human carotid arteries by grating-based phase-contrast tomography (PC-CT) at two different experimental set-ups: (i) applying synchrotron radiation and (ii) using a conventional X-ray tube. Materials and Methods Five ex-vivo carotid artery specimens were examined with PC-CT either at the European Synchrotron Radiation Facility using a monochromatic X-ray beam (2 specimens; 23 keV; pixel size 5.4 µm), or at a laboratory set-up on a conventional X-ray tube (3 specimens; 35-40 kVp; 70 mA; pixel size 100 µm). Tomographic images were reconstructed and compared to histopathology. Two independent readers determined vessel dimensions and one reader determined signal-to-noise ratios (SNR) between PC-CT and absorption images. Results In total, 51 sections were included in the analysis. Images from both set-ups provided sufficient contrast to differentiate individual vessel layers. All PCI-based measurements strongly predicted but significantly overestimated lumen, intima and vessel wall area for both the synchrotron and the laboratory-based measurements as compared with histology (all p<0.001 with slope >0.53 per mm2, 95%-CI: 0.35 to 0.70). Although synchrotron-based images were characterized by higher SNRs than laboratory-based images; both PC-CT set-ups had superior SNRs compared to corresponding conventional absorption-based images (p<0.001). Inter-reader reproducibility was excellent (ICCs >0.98 and >0.84 for synchrotron and for laboratory-based measurements; respectively). Conclusion Experimental PC-CT of carotid specimens is feasible with both synchrotron and conventional X-ray sources, producing high-resolution images suitable for vessel characterization and atherosclerosis research. PMID:24039969

Weighted minimum-norm source estimation of magnetoencephalography utilizing the temporal information of the measured data

NASA Astrophysics Data System (ADS)

Iwaki, Sunao; Ueno, Shoogo

1998-06-01

The weighted minimum-norm estimation (wMNE) is a popular method to obtain the source distribution in the human brain from magneto- and electro- encephalograpic measurements when detailed information about the generator profile is not available. We propose a method to reconstruct current distributions in the human brain based on the wMNE technique with the weighting factors defined by a simplified multiple signal classification (MUSIC) prescanning. In this method, in addition to the conventional depth normalization technique, weighting factors of the wMNE were determined by the cost values previously calculated by a simplified MUSIC scanning which contains the temporal information of the measured data. We performed computer simulations of this method and compared it with the conventional wMNE method. The results show that the proposed method is effective for the reconstruction of the current distributions from noisy data.

Zero-dimensional to three-dimensional nanojoining: current status and potential applications

DOE PAGES

Ma, Ying; Li, Hong; Bridges, Denzel; ...

2016-08-01

We report that the continuing miniaturization of microelectronics is pushing advanced manufacturing into nanomanufacturing. Nanojoining is a bottom-up assembly technique that enables functional nanodevice fabrication with dissimilar nanoscopic building blocks and/or molecular components. Various conventional joining techniques have been modified and re-invented for joining nanomaterials. Our review surveys recent progress in nanojoining methods, as compared to conventional joining processes. Examples of nanojoining are given and classified by the dimensionality of the joining materials. At each classification, nanojoining is reviewed and discussed according to materials specialties, low dimensional processing features, energy input mechanisms and potential applications. The preparation of new intermetallicmore » materials by reactive nanoscale multilayer foils based on self-propagating high-temperature synthesis is highlighted. This review will provide insight into nanojoining fundamentals and innovative applications in power electronics packaging, plasmonic devices, nanosoldering for printable electronics, 3D printing and space manufacturing.« less

Discrimination of transgenic soybean seeds by terahertz spectroscopy

NASA Astrophysics Data System (ADS)

Liu, Wei; Liu, Changhong; Chen, Feng; Yang, Jianbo; Zheng, Lei

2016-10-01

Discrimination of genetically modified organisms is increasingly demanded by legislation and consumers worldwide. The feasibility of a non-destructive discrimination of glyphosate-resistant and conventional soybean seeds and their hybrid descendants was examined by terahertz time-domain spectroscopy system combined with chemometrics. Principal component analysis (PCA), least squares-support vector machines (LS-SVM) and PCA-back propagation neural network (PCA-BPNN) models with the first and second derivative and standard normal variate (SNV) transformation pre-treatments were applied to classify soybean seeds based on genotype. Results demonstrated clear differences among glyphosate-resistant, hybrid descendants and conventional non-transformed soybean seeds could easily be visualized with an excellent classification (accuracy was 88.33% in validation set) using the LS-SVM and the spectra with SNV pre-treatment. The results indicated that THz spectroscopy techniques together with chemometrics would be a promising technique to distinguish transgenic soybean seeds from non-transformed seeds with high efficiency and without any major sample preparation.

Method for nanomachining high aspect ratio structures

DOEpatents

Yun, Wenbing; Spence, John; Padmore, Howard A.; MacDowell, Alastair A.; Howells, Malcolm R.

2004-11-09

A nanomachining method for producing high-aspect ratio precise nanostructures. The method begins by irradiating a wafer with an energetic charged-particle beam. Next, a layer of patterning material is deposited on one side of the wafer and a layer of etch stop or metal plating base is coated on the other side of the wafer. A desired pattern is generated in the patterning material on the top surface of the irradiated wafer using conventional electron-beam lithography techniques. Lastly, the wafer is placed in an appropriate chemical solution that produces a directional etch of the wafer only in the area from which the resist has been removed by the patterning process. The high mechanical strength of the wafer materials compared to the organic resists used in conventional lithography techniques with allows the transfer of the precise patterns into structures with aspect ratios much larger than those previously achievable.

A New Correction Technique for Strain-Gage Measurements Acquired in Transient-Temperature Environments

NASA Technical Reports Server (NTRS)

Richards, W. Lance

1996-01-01

Significant strain-gage errors may exist in measurements acquired in transient-temperature environments if conventional correction methods are applied. As heating or cooling rates increase, temperature gradients between the strain-gage sensor and substrate surface increase proportionally. These temperature gradients introduce strain-measurement errors that are currently neglected in both conventional strain-correction theory and practice. Therefore, the conventional correction theory has been modified to account for these errors. A new experimental method has been developed to correct strain-gage measurements acquired in environments experiencing significant temperature transients. The new correction technique has been demonstrated through a series of tests in which strain measurements were acquired for temperature-rise rates ranging from 1 to greater than 100 degrees F/sec. Strain-gage data from these tests have been corrected with both the new and conventional methods and then compared with an analysis. Results show that, for temperature-rise rates greater than 10 degrees F/sec, the strain measurements corrected with the conventional technique produced strain errors that deviated from analysis by as much as 45 percent, whereas results corrected with the new technique were in good agreement with analytical results.

Accuracy of single-tooth restorations based on intraoral digital and conventional impressions in patients.

PubMed

Boeddinghaus, Moritz; Breloer, Eva Sabina; Rehmann, Peter; Wöstmann, Bernd

2015-11-01

The purpose of this clinical study was to compare the marginal fit of dental crowns based on three different intraoral digital and one conventional impression methods. Forty-nine teeth of altogether 24 patients were prepared to be treated with full-coverage restorations. Digital impressions were made using three intraoral scanners: Sirona CEREC AC Omnicam (OCam), Heraeus Cara TRIOS and 3M Lava True Definition (TDef). Furthermore, a gypsum model based on a conventional impression (EXA'lence, GC, Tokyo, Japan) was scanned with a standard laboratory scanner (3Shape D700). Based on the dataset obtained, four zirconia copings per tooth were produced. The marginal fit of the copings in the patient's mouth was assessed employing a replica technique. Overall, seven measurement copings did not fit and, therefore, could not be assessed. The marginal gap was 88 μm (68-136 μm) [median/interquartile range] for the TDef, 112 μm (94-149 μm) for the Cara TRIOS, 113 μm (81-157 μm) for the laboratory scanner and 149 μm (114-218 μm) for the OCam. There was a statistically significant difference between the OCam and the other groups (p < 0.05). Within the limitations of this study, it can be concluded that zirconia copings based on intraoral scans and a laboratory scans of a conventional model are comparable to one another with regard to their marginal fit. Regarding the results of this study, the digital intraoral impression can be considered as an alternative to a conventional impression with a consecutive digital workflow when the finish line is clearly visible and it is possible to keep it dry.

MEMS-based platforms for mechanical manipulation and characterization of cells

NASA Astrophysics Data System (ADS)

Pan, Peng; Wang, Wenhui; Ru, Changhai; Sun, Yu; Liu, Xinyu

2017-12-01

Mechanical manipulation and characterization of single cells are important experimental techniques in biological and medical research. Because of the microscale sizes and highly fragile structures of cells, conventional cell manipulation and characterization techniques are not accurate and/or efficient enough or even cannot meet the more and more demanding needs in different types of cell-based studies. To this end, novel microelectromechanical systems (MEMS)-based technologies have been developed to improve the accuracy, efficiency, and consistency of various cell manipulation and characterization tasks, and enable new types of cell research. This article summarizes existing MEMS-based platforms developed for cell mechanical manipulation and characterization, highlights their specific design considerations making them suitable for their designated tasks, and discuss their advantages and limitations. In closing, an outlook into future trends is also provided.

New method for characterizing paper coating structures using argon ion beam milling and field emission scanning electron microscopy.

PubMed

Dahlström, C; Allem, R; Uesaka, T

2011-02-01

We have developed a new method for characterizing microstructures of paper coating using argon ion beam milling technique and field emission scanning electron microscopy. The combination of these two techniques produces extremely high-quality images with very few artefacts, which are particularly suited for quantitative analyses of coating structures. A new evaluation method has been developed by using marker-controlled watershed segmentation technique of the secondary electron images. The high-quality secondary electron images with well-defined pores makes it possible to use this semi-automatic segmentation method. One advantage of using secondary electron images instead of backscattered electron images is being able to avoid possible overestimation of the porosity because of the signal depth. A comparison was made between the new method and the conventional method using greyscale histogram thresholding of backscattered electron images. The results showed that the conventional method overestimated the pore area by 20% and detected around 5% more pores than the new method. As examples of the application of the new method, we have investigated the distributions of coating binders, and the relationship between local coating porosity and base sheet structures. The technique revealed, for the first time with direct evidence, the long-suspected coating non-uniformity, i.e. binder migration, and the correlation between coating porosity versus base sheet mass density, in a straightforward way. © 2010 The Authors Journal compilation © 2010 The Royal Microscopical Society.

Fabricating fiber Bragg gratings with two phase masks based on reconstruction-equivalent-chirp technique.

PubMed

Gao, Liang; Chen, Xiangfei; Xiong, Jintian; Liu, Shengchun; Pu, Tao

2012-01-30

Based on reconstruction-equivalent-chirp (REC) technique, a novel solution for fabricating low-cost long fiber Bragg gratings (FBGs) with desired properties is proposed and initially studied. A proof-of-concept experiment is demonstrated with two conventional uniform phase masks and a submicron-precision translation stage, successfully. It is shown that the original phase shift (OPS) caused by phase mismatch of the two phase masks can be compensated by the equivalent phase shift (EPS) at the ±1st channels of sampled FBGs, separately. Furthermore, as an example, a π phase-shifted FBG of about 90 mm is fabricated by using these two 50mm-long uniform phase masks based on the presented method.

Single-step fabrication of thin-film linear variable bandpass filters based on metal-insulator-metal geometry.

PubMed

Williams, Calum; Rughoobur, Girish; Flewitt, Andrew J; Wilkinson, Timothy D

2016-11-10

A single-step fabrication method is presented for ultra-thin, linearly variable optical bandpass filters (LVBFs) based on a metal-insulator-metal arrangement using modified evaporation deposition techniques. This alternate process methodology offers reduced complexity and cost in comparison to conventional techniques for fabricating LVBFs. We are able to achieve linear variation of insulator thickness across a sample, by adjusting the geometrical parameters of a typical physical vapor deposition process. We demonstrate LVBFs with spectral selectivity from 400 to 850 nm based on Ag (25 nm) and MgF₂ (75-250 nm). Maximum spectral transmittance is measured at ∼70% with a Q-factor of ∼20.

Steganographic optical image encryption system based on reversible data hiding and double random phase encoding

NASA Astrophysics Data System (ADS)

Chuang, Cheng-Hung; Chen, Yen-Lin

2013-02-01

This study presents a steganographic optical image encryption system based on reversible data hiding and double random phase encoding (DRPE) techniques. Conventional optical image encryption systems can securely transmit valuable images using an encryption method for possible application in optical transmission systems. The steganographic optical image encryption system based on the DRPE technique has been investigated to hide secret data in encrypted images. However, the DRPE techniques vulnerable to attacks and many of the data hiding methods in the DRPE system can distort the decrypted images. The proposed system, based on reversible data hiding, uses a JBIG2 compression scheme to achieve lossless decrypted image quality and perform a prior encryption process. Thus, the DRPE technique enables a more secured optical encryption process. The proposed method extracts and compresses the bit planes of the original image using the lossless JBIG2 technique. The secret data are embedded in the remaining storage space. The RSA algorithm can cipher the compressed binary bits and secret data for advanced security. Experimental results show that the proposed system achieves a high data embedding capacity and lossless reconstruction of the original images.

Conventional Vs Digital Impressions: Acceptability, Treatment Comfort and Stress Among Young Orthodontic Patients.

PubMed

Mangano, Alessandro; Beretta, Matteo; Luongo, Giuseppe; Mangano, Carlo; Mangano, Francesco

2018-01-01

The objective of the present study was to compare patients' acceptability, comfort and stress with conventional and digital impressions. Thirty young orthodontic patients (15 males and 15 females) who had no previous experience of impressions were enrolled in this study. Conventional impressions for orthodontic study models of the dental arches were taken using an alginate impression material (Hydrogum ® , Zhermack Spa, Badia Polesine, Rovigo, Italy). Fifteen days later, digital impressions of both arches were acquired using an intraoral scanner (CS3600 ® , Carestream Dental, Rochester, NY, USA). Immediately after impression taking, patients' acceptability, comfort and stress were measured using two questionnaires and the State anxiety scale. Data showed no difference in terms of anxiety and stress; however, patients preferred the use of digital impressions systems instead of conventional impression techniques. Alginate impressions resulted as fast as digital impressions. Digital impressions resulted the most accepted and comfortable impression technique in young orthodontic patients, when compared to conventional techniques.

Pain control in a randomized, controlled, clinical trial comparing moist exposed burn ointment and conventional methods in patients with partial-thickness burns.

PubMed

Ang, Erik; Lee, S-T; Gan, Christine S-G; Chan, Y-H; Cheung, Y-B; Machin, D

2003-01-01

Conventional management of partial-thickness burn wounds includes the use of paraffin gauze dressing, frequently with topical silver-based antibacterial creams. Some creams form an overlying slough that renders wound assessment difficult and are painful upon application. An alternative to conventional management, moist exposed burn ointment (MEBO), has been proposed as a topical agent that may accelerate wound healing and have antibacterial and analgesic properties. One hundred fifteen patients with partial-thickness burns were randomly assigned to conventional (n = 58) or MEBO treatment (n = 57). A verbal numerical rating score of pain was made in the morning, after burn dressing, and some 8 hours later. Patient pain profiles were summarized by locally weighted regression smoothing technique curves and the difference between treatments estimated using multilevel regression techniques. Mean verbal numerical rating scale pain levels (cm) in week 1 for all patients were highest at 3.2 for the after dressing assessment, lowest in the evening at 2.6, and intermediate in the morning at 3.0. This pattern continued at similar levels in week 2 and then declined by a mean of 0.5 in all groups in week 3. There was little evidence to suggest a difference in pain levels by treatment group with the exception of the postdressing pain levels in the first week when those receiving MEBO had a mean level of 0.7 cm (95% confidence interval, 0.2 to 1.1) lower than those on conventional therapy. MEBO appeared to bring greater pain relief for the postdressing assessment during the first week after burns. This initial relief, together with comparable pain levels experienced on other occasions, indicates that MEBO could be an alternative to conventional burns management.

Renal autotransplantation: current perspectives.

PubMed

Stewart, B H; Banowsky, L H; Hewitt, C B; Straffon, R A

1977-09-01

Autotransplantation, with or without an extracorporeal renal operation, has been done 39 times in 37 patients. Indications for the procedure included several ureteral injury in 4 patients, failed supravesical diversion in 2, renal carcinoma in a solitary kidney in 1, renovascular hypertension in 1 and donor arterial reconstruction before renal transplantation in 29. Success was obtained in all but 2 procedures, both of which involved previously operated kidneys with severe inflammation and adhesions involving the renal pelvis and pedicle. Based on our experience and a review of currently available literature we believe that renal autotransplantation and extracorporeal reconstruction can provide the best solution for patients with severe renovascular and ureteral disease not correctable by conventional operative techniques. The technique can be of particular value in removing centrally located tumors in solitary kidneys and in preparing donor kidneys with abnormal arteries for renal transplantation. The role of autotransplantation in the management of advanced renal trauma and calculus disease is less clear. A long-term comparison of patients treated by extracorporeal nephrolithotomy versus conventional lithotomy techniques will be necessary before a conclusion is reached in these disease categories.

Renal autotransplantation: current perspectives.

PubMed

Stewart, B H; Banowsky, L H; Hewitt, C B; Straffon, R A

1976-01-01

Autotransplantation, with or without an extracorporeal renal operation, has been done 39 times in 37 patients. Indications for the procedure included severe ureteral injury in 4 patients, failed supravesical diversion in 2, renal carcinoma in a solitary kidney in 1, renovascular hypertension in 1 and donor arterial reconstruction before renal transplantation in 29. Success was obtained in all but 2 procedures, both of which involved previously operated kidneys with severe inflammation and adhesions involving the renal pelvis and pedicle. Based on our experience and a review of currently available literature we believe that renal autotransplantation and extracorporeal reconstruction can provide the best solution for patients with severe renovascular and ureteral disease not correctable by conventional operative techniques. The technique can be of particular value in removing centrally located tumors in solitary kidneys and in preparing donor kidneys with abnormal arteries for renal transplantation. The role of autotransplantation in the management of advanced renal trauma and calculus disease is less clear. A long-term comparison of patients treated by extracorporeal nephrolithotomy versus conventional lithotomy techniques will be necessary before a conclusion is reached in these disease categories.

MX Siting Investigation. Geotechnical Siting Status Report. Volume 2.

DTIC Science & Technology

1978-06-21

greater tnan a nominal 50 feet deep. Rock is considered any earth material which is not readily rippable by conventional excavation techniques. b. Surface...material which is not readily rippable by conventional excavation techniques. _ b. Surface water absent and occurrences of ground water greater than a

Joint Dictionary Learning-Based Non-Negative Matrix Factorization for Voice Conversion to Improve Speech Intelligibility After Oral Surgery.

PubMed

Fu, Szu-Wei; Li, Pei-Chun; Lai, Ying-Hui; Yang, Cheng-Chien; Hsieh, Li-Chun; Tsao, Yu

2017-11-01

Objective: This paper focuses on machine learning based voice conversion (VC) techniques for improving the speech intelligibility of surgical patients who have had parts of their articulators removed. Because of the removal of parts of the articulator, a patient's speech may be distorted and difficult to understand. To overcome this problem, VC methods can be applied to convert the distorted speech such that it is clear and more intelligible. To design an effective VC method, two key points must be considered: 1) the amount of training data may be limited (because speaking for a long time is usually difficult for postoperative patients); 2) rapid conversion is desirable (for better communication). Methods: We propose a novel joint dictionary learning based non-negative matrix factorization (JD-NMF) algorithm. Compared to conventional VC techniques, JD-NMF can perform VC efficiently and effectively with only a small amount of training data. Results: The experimental results demonstrate that the proposed JD-NMF method not only achieves notably higher short-time objective intelligibility (STOI) scores (a standardized objective intelligibility evaluation metric) than those obtained using the original unconverted speech but is also significantly more efficient and effective than a conventional exemplar-based NMF VC method. Conclusion: The proposed JD-NMF method may outperform the state-of-the-art exemplar-based NMF VC method in terms of STOI scores under the desired scenario. Significance: We confirmed the advantages of the proposed joint training criterion for the NMF-based VC. Moreover, we verified that the proposed JD-NMF can effectively improve the speech intelligibility scores of oral surgery patients. Objective: This paper focuses on machine learning based voice conversion (VC) techniques for improving the speech intelligibility of surgical patients who have had parts of their articulators removed. Because of the removal of parts of the articulator, a patient's speech may be distorted and difficult to understand. To overcome this problem, VC methods can be applied to convert the distorted speech such that it is clear and more intelligible. To design an effective VC method, two key points must be considered: 1) the amount of training data may be limited (because speaking for a long time is usually difficult for postoperative patients); 2) rapid conversion is desirable (for better communication). Methods: We propose a novel joint dictionary learning based non-negative matrix factorization (JD-NMF) algorithm. Compared to conventional VC techniques, JD-NMF can perform VC efficiently and effectively with only a small amount of training data. Results: The experimental results demonstrate that the proposed JD-NMF method not only achieves notably higher short-time objective intelligibility (STOI) scores (a standardized objective intelligibility evaluation metric) than those obtained using the original unconverted speech but is also significantly more efficient and effective than a conventional exemplar-based NMF VC method. Conclusion: The proposed JD-NMF method may outperform the state-of-the-art exemplar-based NMF VC method in terms of STOI scores under the desired scenario. Significance: We confirmed the advantages of the proposed joint training criterion for the NMF-based VC. Moreover, we verified that the proposed JD-NMF can effectively improve the speech intelligibility scores of oral surgery patients.

Applying problem-based learning to otolaryngology teaching.

PubMed

Abou-Elhamd, K A; Rashad, U M; Al-Sultan, A I

2011-02-01

Undergraduate medical education requires ongoing improvement in order to keep pace with the changing demands of twenty-first century medical practice. Problem-based learning is increasingly being adopted in medical schools worldwide. We review its application in the specialty of ENT, and we present our experience of using this approach combined with more traditional methods. We introduced problem-based learning techniques into the ENT course taught to fifth-year medical students at Al-Ahsa College of Medicine, King Faisal University, Saudi Arabia. As a result, the teaching schedule included both clinical and theoretical activities. Six clinical teaching days were allowed for history-taking, examination techniques and clinical scenario discussion. Case scenarios were discussed in small group teaching sessions. Conventional methods were employed to teach audiology and ENT radiology (one three-hour session each); a three-hour simulation laboratory session and three-hour student presentation were also scheduled. In addition, students attended out-patient clinics for three days, and used multimedia facilities to learn about various otolaryngology diseases (in another three-hour session). This input was supplemented with didactic teaching in the form of 16 instructional lectures per semester (one hour per week). From our teaching experience, we believe that the application of problem-based learning to ENT teaching has resulted in a substantial increase in students' knowledge. Furthermore, students have given encouraging feedback on their experience of combined problem-based learning and conventional teaching methods.

Comparison of stromal hydration techniques for clear corneal cataract incisions: conventional hydration versus anterior stromal pocket hydration.

PubMed

Mifflin, Mark D; Kinard, Krista; Neuffer, Marcus C

2012-06-01

Anterior stromal pocket hydration was compared with conventional hydration for preventing wound leak after 2.8 mm uniplanar clear corneal incisions (CCIs) in patients having routine cataract surgery. Conventional hydration involves hydration of the lateral walls of the main incision with visible whitening of the stroma. The anterior stromal pocket hydration technique involves creation of an additional supraincisional stromal pocket overlying the main incision, which is then hydrated instead of the main incision. Sixty-six eyes of 48 patients were included in the data analysis with 33 assigned to each study group. The anterior stromal pocket hydration technique was significantly better than conventional hydration in preventing wound leak due to direct pressure on the posterior lip of the incision. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

The voice of Holland: Dutch public and patient's opinion favours single-port laparoscopy.

PubMed

Fransen, Sofie Af; Broeders, Epm; Stassen, Lps; Bouvy, Nd

2014-07-01

Single-port laparoscopy is prospected as the future of minimal invasive surgery. It is hypothesised to cause less post operative pain, with a shorter hospitalisation period and improved cosmetic results. Population- and patient-based opinion is important for the adaptation of new techniques. This study aimed to assess the opinion and perception of a healthy population and a patient population on single-port laparoscopy compared with conventional laparoscopy. An anonymous 33-item questionnaire, describing conventional and single-port laparoscopy, was given to 101 patients and 104 healthy volunteers. The survey participants (median age 44 years; range 17-82 years) were asked questions about their personal situation and their expectations and perceptions of the two different surgical techniques; conventional multi-port laparoscopy and single-port laparoscopy. A total of 72% of the participants had never heard of single-port laparoscopy before. The most important concern in both groups was the risk of surgical complications. When complication risks remain similar, 80% prefers single-port laparoscopy to conventional laparoscopy. When the risk of complications increases from 1% to 10%, 43% of all participants prefer single-port laparoscopy. A total of 70% of the participants are prepared to receive treatment in another hospital if single-port surgery is not performed in their hometown hospital. The preference for single-port approach was higher in the female population. Although cure and safety remain the main concerns, the population and patients group have a favourable perception of single-port surgery. The impact of public opinion and patient perception towards innovative techniques is undeniable. If the safety of the two different procedures is similar, this study shows a positive attitude of both participant groups in favour of single-port laparoscopy. However, solid scientific proof for the safety and feasibility of this new surgical technique needs to be obtained before this procedure can be implemented into everyday practice.

[Bases and methods of suturing].

PubMed

Vogt, P M; Altintas, M A; Radtke, C; Meyer-Marcotty, M

2009-05-01

If pharmaceutic modulation of scar formation does not improve the quality of the healing process over conventional healing, the surgeon must rely on personal skill and experience. Therefore a profound knowledge of wound healing based on experimental and clinical studies supplemented by postsurgical means of scar management and basic techniques of planning incisions, careful tissue handling, and thorough knowledge of suturing remain the most important ways to avoid abnormal scarring. This review summarizes the current experimental and clinical bases of surgical scar management.

CAD/CAM complete dentures: a review of two commercial fabrication systems.

PubMed

Kattadiyil, Mathew T; Goodacre, Charles J; Baba, Nadim Z

2013-06-01

The use of computer-aided design and computer-aided manufacturing (CAD/CAM) has become available for complete dentures through the AvaDent and Dentca systems. AvaDent uses laser scanning and computer technology. Teeth are arranged and bases formed using proprietary software.The bases are milled from prepolymerized pucks of resin. Dentca uses computer software to produce virtual maxillary and mandibular edentulous ridges, arrange the teeth and form bases. The dentures are fabricated using a conventional processing technique.

A new fiber sensor based on graphene coating technique for wearable equipment

NASA Astrophysics Data System (ADS)

Wu, Ensen; Zhang, Jinnan; Qiao, Min; Cao, Yanghua; Wang, Qi; Ren, Xiaomin; Zuo, Yong

2018-02-01

We propose and implement a graphene-based composite fiber sensor in this paper. The advantages of this composite fiber lie in simple and practicable fabrication, high sensitivity to tensile strain deformation, wide maximal sensing range. The experiment shows that the composite fiber can monitor small signals of the body and massive movements in conventionality condition such as human pulse and the movement of elbow. This suggests that this graphene-based composite fiber has a broad prospect in health monitoring and movement recognition.

Design and optimization of resonance-based efficient wireless power delivery systems for biomedical implants.

PubMed

Ramrakhyani, A K; Mirabbasi, S; Mu Chiao

2011-02-01

Resonance-based wireless power delivery is an efficient technique to transfer power over a relatively long distance. This technique typically uses four coils as opposed to two coils used in conventional inductive links. In the four-coil system, the adverse effects of a low coupling coefficient between primary and secondary coils are compensated by using high-quality (Q) factor coils, and the efficiency of the system is improved. Unlike its two-coil counterpart, the efficiency profile of the power transfer is not a monotonically decreasing function of the operating distance and is less sensitive to changes in the distance between the primary and secondary coils. A four-coil energy transfer system can be optimized to provide maximum efficiency at a given operating distance. We have analyzed the four-coil energy transfer systems and outlined the effect of design parameters on power-transfer efficiency. Design steps to obtain the efficient power-transfer system are presented and a design example is provided. A proof-of-concept prototype system is implemented and confirms the validity of the proposed analysis and design techniques. In the prototype system, for a power-link frequency of 700 kHz and a coil distance range of 10 to 20 mm, using a 22-mm diameter implantable coil resonance-based system shows a power-transfer efficiency of more than 80% with an enhanced operating range compared to ~40% efficiency achieved by a conventional two-coil system.

Invariant domain watermarking using heaviside function of order alpha and fractional Gaussian field.

PubMed

Abbasi, Almas; Woo, Chaw Seng; Ibrahim, Rabha Waell; Islam, Saeed

2015-01-01

Digital image watermarking is an important technique for the authentication of multimedia content and copyright protection. Conventional digital image watermarking techniques are often vulnerable to geometric distortions such as Rotation, Scaling, and Translation (RST). These distortions desynchronize the watermark information embedded in an image and thus disable watermark detection. To solve this problem, we propose an RST invariant domain watermarking technique based on fractional calculus. We have constructed a domain using Heaviside function of order alpha (HFOA). The HFOA models the signal as a polynomial for watermark embedding. The watermark is embedded in all the coefficients of the image. We have also constructed a fractional variance formula using fractional Gaussian field. A cross correlation method based on the fractional Gaussian field is used for watermark detection. Furthermore the proposed method enables blind watermark detection where the original image is not required during the watermark detection thereby making it more practical than non-blind watermarking techniques. Experimental results confirmed that the proposed technique has a high level of robustness.

Non-Conventional Techniques for the Study of Phase Transitions in NiTi-Based Alloys

NASA Astrophysics Data System (ADS)

Nespoli, Adelaide; Villa, Elena; Passaretti, Francesca; Albertini, Franca; Cabassi, Riccardo; Pasquale, Massimo; Sasso, Carlo Paolo; Coïsson, Marco

2014-07-01

Differential scanning calorimetry and electrical resistance measurements are the two most common techniques for the study of the phase transition path and temperatures of shape memory alloys (SMA) in stress-free condition. Besides, it is well known that internal friction measurements are also useful for this purpose. There are indeed some further techniques which are seldom used for the basic characterization of SMA transition: dilatometric analysis, magnetic measurements, and Seebeck coefficient study. In this work, we discuss the attitude of these techniques for the study of NiTi-based phase transition. Measurements were conducted on several fully annealed Ni50- x Ti50Cu x samples ranging from 3 to 10 at.% in Cu content, fully annealed at 850 °C for 1 h in vacuum and quenched in water at room temperature. Results show that all these techniques are sensitive to phase transition, and they provide significant information about the existence of intermediate phases.

Invariant Domain Watermarking Using Heaviside Function of Order Alpha and Fractional Gaussian Field

PubMed Central

Abbasi, Almas; Woo, Chaw Seng; Ibrahim, Rabha Waell; Islam, Saeed

2015-01-01

Digital image watermarking is an important technique for the authentication of multimedia content and copyright protection. Conventional digital image watermarking techniques are often vulnerable to geometric distortions such as Rotation, Scaling, and Translation (RST). These distortions desynchronize the watermark information embedded in an image and thus disable watermark detection. To solve this problem, we propose an RST invariant domain watermarking technique based on fractional calculus. We have constructed a domain using Heaviside function of order alpha (HFOA). The HFOA models the signal as a polynomial for watermark embedding. The watermark is embedded in all the coefficients of the image. We have also constructed a fractional variance formula using fractional Gaussian field. A cross correlation method based on the fractional Gaussian field is used for watermark detection. Furthermore the proposed method enables blind watermark detection where the original image is not required during the watermark detection thereby making it more practical than non-blind watermarking techniques. Experimental results confirmed that the proposed technique has a high level of robustness. PMID:25884854

Comparative study between manual injection intraosseous anesthesia and conventional oral anesthesia.

PubMed

Peñarrocha-Oltra, D; Ata-Ali, J; Oltra-Moscardó, M-J; Peñarrocha-Diago, M-A; Peñarrocha, M

2012-03-01

To compare intraosseous anesthesia (IA) with the conventional oral anesthesia techniques. A simple-blind, prospective clinical study was carried out. Each patient underwent two anesthetic techniques: conventional (local infiltration and locoregional anesthetic block) and intraosseous, for respective dental operations. In order to allow comparison of IA versus conventional anesthesia, the two operations were similar and affected the same two teeth in opposite quadrants. A total of 200 oral anesthetic procedures were carried out in 100 patients. The mean patient age was 28.6±9.92 years. Fifty-five vestibular infiltrations and 45 mandibular blocks were performed. All patients were also subjected to IA. The type of intervention (conservative or endodontic) exerted no significant influence (p=0.58 and p=0.62, respectively). The latency period was 8.52±2.44 minutes for the conventional techniques and 0.89±0.73 minutes for IA - the difference being statistically significant (p<0.05). Regarding patient anesthesia sensation, the infiltrative techniques lasted a maximum of one hour, the inferior alveolar nerve blocks lasted between 1-3 hours, and IA lasted only 2.5 minutes - the differences being statistically significant (p≤0.0000, Φ=0.29). Anesthetic success was recorded in 89% of the conventional procedures and in 78% of the IA. Most patients preferred IA (61%)(p=0.0032). The two anesthetic procedures have been compared for latency, duration of anesthetic effect, anesthetic success rate and patient preference. Intraosseous anesthesia has been shown to be a technique to be taken into account when planning conservative and endodontic treatments.

A comparison of conventional capture versus PIT reader techniques for estimating survival and capture probabilities of big brown bats (Eptesicus fuscus)

USGS Publications Warehouse

Ellison, L.E.; O'Shea, T.J.; Neubaum, D.J.; Neubaum, M.A.; Pearce, R.D.; Bowen, R.A.

2007-01-01

We compared conventional capture (primarily mist nets and harp traps) and passive integrated transponder (PIT) tagging techniques for estimating capture and survival probabilities of big brown bats (Eptesicus fuscus) roosting in buildings in Fort Collins, Colorado. A total of 987 female adult and juvenile bats were captured and marked by subdermal injection of PIT tags during the summers of 2001-2005 at five maternity colonies in buildings. Openings to roosts were equipped with PIT hoop-style readers, and exit and entry of bats were passively monitored on a daily basis throughout the summers of 2002-2005. PIT readers 'recaptured' adult and juvenile females more often than conventional capture events at each roost. Estimates of annual capture probabilities for all five colonies were on average twice as high when estimated from PIT reader data (P?? = 0.93-1.00) than when derived from conventional techniques (P?? = 0.26-0.66), and as a consequence annual survival estimates were more precisely estimated when using PIT reader encounters. Short-term, daily capture estimates were also higher using PIT readers than conventional captures. We discuss the advantages and limitations of using PIT tags and passive encounters with hoop readers vs. conventional capture techniques for estimating these vital parameters in big brown bats. ?? Museum and Institute of Zoology PAS.

Effect of Simplifying Drilling Technique on Heat Generation During Osteotomy Preparation for Dental Implant.

PubMed

El-Kholey, Khalid E; Ramasamy, Saravanan; Kumar R, Sheetal; Elkomy, Aamna

2017-12-01

To test the hypothesis that there would be no difference in heat production by reducing the number of drills during the implant site preparation relative to conventional drilling sequence. A total of 120 implant site preparations with 3 different diameters (3.6, 4.3, and 4.6 mm) were performed on bovine ribs. Within the same diameter group, half of the preparations were performed by a simplified drilling procedure (pilot drill + final diameter drill) and other half using the conventional drilling protocol (pilot drill followed by graduated series of drills to widen the site). Heat production by different drilling techniques was evaluated by measuring the bone temperature using k-type thermocouple and a sensitive thermometer before and after each drill. Mean for maximum temperature increase during site preparation of the 3.6, 4.3, and 4.6-mm implants was 2.45, 2.60, and 2.95° when the site was prepared by the simplified procedure, whereas it was 2.85, 3.10, and 3.60° for the sites prepared by the conventional technique, respectively. No significant difference in temperature increase was found when implants of the 3 different diameters were prepared either by the conventional or simplified drilling procedure. The simplified drilling technique produced similar amount of heat comparable to the conventional technique that proved the initial hypothesis.

Dental Students' Perceptions of Digital and Conventional Impression Techniques: A Randomized Controlled Trial.

PubMed

Zitzmann, Nicola U; Kovaltschuk, Irina; Lenherr, Patrik; Dedem, Philipp; Joda, Tim

2017-10-01

The aim of this randomized controlled trial was to analyze inexperienced dental students' perceptions of the difficulty and applicability of digital and conventional implant impressions and their preferences including performance. Fifty undergraduate dental students at a dental school in Switzerland were randomly divided into two groups (2×25). Group A first took digital impressions in a standardized phantom model and then conventional impressions, while the procedures were reversed for Group B. Participants were asked to complete a VAS questionnaire (0-100) on the level of difficulty and applicability (user/patient-friendliness) of both techniques. They were asked which technique they preferred and perceived to be more efficient. A quotient of "effective scan time per software-recorded time" (TRIOS) was calculated as an objective quality indicator for intraoral optical scanning (IOS). The majority of students perceived IOS as easier than the conventional technique. Most (72%) preferred the digital approach using IOS to take the implant impression to the conventional method (12%) or had no preference (12%). Although total work was similar for males and females, the TRIOS quotient indicated that male students tended to use their time more efficiently. In this study, dental students with no clinical experience were very capable of acquiring digital tools, indicating that digital impression techniques can be included early in the dental curriculum to help them catch up with ongoing development in computer-assisted technologies used in oral rehabilitation.

Pilot Study of an Open-source Image Analysis Software for Automated Screening of Conventional Cervical Smears.

PubMed

Sanyal, Parikshit; Ganguli, Prosenjit; Barui, Sanghita; Deb, Prabal

2018-01-01

The Pap stained cervical smear is a screening tool for cervical cancer. Commercial systems are used for automated screening of liquid based cervical smears. However, there is no image analysis software used for conventional cervical smears. The aim of this study was to develop and test the diagnostic accuracy of a software for analysis of conventional smears. The software was developed using Python programming language and open source libraries. It was standardized with images from Bethesda Interobserver Reproducibility Project. One hundred and thirty images from smears which were reported Negative for Intraepithelial Lesion or Malignancy (NILM), and 45 images where some abnormality has been reported, were collected from the archives of the hospital. The software was then tested on the images. The software was able to segregate images based on overall nuclear: cytoplasmic ratio, coefficient of variation (CV) in nuclear size, nuclear membrane irregularity, and clustering. 68.88% of abnormal images were flagged by the software, as well as 19.23% of NILM images. The major difficulties faced were segmentation of overlapping cell clusters and separation of neutrophils. The software shows potential as a screening tool for conventional cervical smears; however, further refinement in technique is required.

Method for improving accuracy in full evaporation headspace analysis.

PubMed

Xie, Wei-Qi; Chai, Xin-Sheng

2017-05-01

We report a new headspace analytical method in which multiple headspace extraction is incorporated with the full evaporation technique. The pressure uncertainty caused by the solid content change in the samples has a great impact to the measurement accuracy in the conventional full evaporation headspace analysis. The results (using ethanol solution as the model sample) showed that the present technique is effective to minimize such a problem. The proposed full evaporation multiple headspace extraction analysis technique is also automated and practical, and which could greatly broaden the applications of the full-evaporation-based headspace analysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diffraction enhance x-ray imaging for quantitative phase contrast studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agrawal, A. K.; Singh, B., E-mail: balwants@rrcat.gov.in; Kashyap, Y. S.

2016-05-23

Conventional X-ray imaging based on absorption contrast permits limited visibility of feature having small density and thickness variations. For imaging of weakly absorbing material or materials possessing similar densities, a novel phase contrast imaging techniques called diffraction enhanced imaging has been designed and developed at imaging beamline Indus-2 RRCAT Indore. The technique provides improved visibility of the interfaces and show high contrast in the image forsmall density or thickness gradients in the bulk. This paper presents basic principle, instrumentation and analysis methods for this technique. Initial results of quantitative phase retrieval carried out on various samples have also been presented.

Dual-energy contrast-enhanced mammography.

PubMed

Travieso Aja, M M; Rodríguez Rodríguez, M; Alayón Hernández, S; Vega Benítez, V; Luzardo, O P

2014-01-01

The degree of vascularization in breast lesions is related to their malignancy. For this reason, functional diagnostic imaging techniques have become important in recent years. Dual-energy contrast-enhanced mammography is a new, apparently promising technique in breast cancer that provides information about the degree of vascularization of the lesion in addition to the morphological information provided by conventional mammography. This article describes the state of the art for dual-energy contrast-enhanced mammography. Based on 15 months' clinical experience, we illustrate this review with clinical cases that allow us to discuss the advantages and limitations of this technique. Copyright © 2014 SERAM. Published by Elsevier Espana. All rights reserved.

MO-FG-CAMPUS-IeP1-02: Dose Reduction in Contrast-Enhanced Digital Mammography Using a Photon-Counting Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S; Kang, S; Eom, J

Purpose: Photon-counting detectors (PCDs) allow multi-energy X-ray imaging without additional exposures and spectral overlap. This capability results in the improvement of accuracy of material decomposition for dual-energy X-ray imaging and the reduction of radiation dose. In this study, the PCD-based contrast-enhanced dual-energy mammography (CEDM) was compared with the conventional CDEM in terms of radiation dose, image quality and accuracy of material decomposition. Methods: A dual-energy model was designed by using Beer-Lambert’s law and rational inverse fitting function for decomposing materials from a polychromatic X-ray source. A cadmium zinc telluride (CZT)-based PCD, which has five energy thresholds, and iodine solutions includedmore » in a 3D half-cylindrical phantom, which composed of 50% glandular and 50% adipose tissues, were simulated by using a Monte Carlo simulation tool. The low- and high-energy images were obtained in accordance with the clinical exposure conditions for the conventional CDEM. Energy bins of 20–33 and 34–50 keV were defined from X-ray energy spectra simulated at 50 kVp with different dose levels for implementing the PCD-based CDEM. The dual-energy mammographic techniques were compared by means of absorbed dose, noise property and normalized root-mean-square error (NRMSE). Results: Comparing to the conventional CEDM, the iodine solutions were clearly decomposed for the PCD-based CEDM. Although the radiation dose for the PCD-based CDEM was lower than that for the conventional CEDM, the PCD-based CDEM improved the noise property and accuracy of decomposition images. Conclusion: This study demonstrates that the PCD-based CDEM allows the quantitative material decomposition, and reduces radiation dose in comparison with the conventional CDEM. Therefore, the PCD-based CDEM is able to provide useful information for detecting breast tumor and enhancing diagnostic accuracy in mammography.« less

Problem Based Learning (PBL) - An Effective Approach to Improve Learning Outcomes in Medical Teaching.

PubMed

Preeti, Bajaj; Ashish, Ahuja; Shriram, Gosavi

2013-12-01

As the "Science of Medicine" is getting advanced day-by-day, need for better pedagogies & learning techniques are imperative. Problem Based Learning (PBL) is an effective way of delivering medical education in a coherent, integrated & focused manner. It has several advantages over conventional and age-old teaching methods of routine. It is based on principles of adult learning theory, including student's motivation, encouragement to set goals, think critically about decision making in day-to-day operations. Above all these, it stimulates challenge acceptance and learning curiosity among students and creates pragmatic educational program. To measure the effectiveness of the "Problem Based Learning" as compared to conventional theory/didactic lectures based learning. The study was conducted on 72 medical students from Dayanand Medical College & Hospital, Ludhiana. Two modules of problem based sessions designed and delivered. Pre & Post-test score's scientific statistical analysis was done. Student feed-back received based on questionnaire in the five-point Likert scale format. Significant improvement in overall performance observed. Feedback revealed majority agreement that "Problem-based learning" helped them create interest (88.8 %), better understanding (86%) & promotes self-directed subject learning (91.6 %). Substantial improvement in the post-test scores clearly reveals acceptance of PBL over conventional learning. PBL ensures better practical learning, ability to create interest, subject understanding. It is a modern-day educational strategy, an effective tool to objectively improve the knowledge acquisition in Medical Teaching.

Combining conventional and thermal drilling in order to increase speed and reduce costs of drilling operations to access deep geothermal resources

NASA Astrophysics Data System (ADS)

Rossi, Edoardo; Kant, Michael A.; von Rohr, Philipp Rudolf; Saar, Martin O.

2017-04-01

The exploitation of deep geothermal resources for energy production relies on finding cost effective solutions to increase the drilling performance in hard rocks. Conventional rotary drilling techniques, based on mechanical rock exportation, result in high rates of drilling tool wearing, causing significant costs. Additionally, rotary drilling results in low drilling speeds in the typically hard crystalline basement rocks targeted for enhanced geothermal energy utilization technologies. Furthermore, even lower overall drilling rates result, when considering tripping times required to exchange worn drill tools. Therefore, alternative drilling techniques, such as hammering, thermal drilling, plasma drilling, and jetting processes are widely investigated in order to provide cost-effective alternatives to conventional drilling methods. A promising approach, that combines conventional rotary and thermal drilling techniques, is investigated in the present work. Here, the rock material is thermally weakened before being exported by conventional cutters. Heat is locally provided by a flame, which moves over the rock surface, heat-treating the material. Besides reducing the rock strength, an in-depth smoothening effect of the mechanical rock properties is observed due to the thermal treatment. This results in reduced rates of drill bit wearing and higher rates of penetration, which in turn decreases drilling costs significantly, particularly for deep-drilling projects. Due to the high heating rates, rock-hardening, commonly observed at moderate temperatures, can be avoided. The flame action can be modelled as a localized, high heat transfer coefficient flame treatment, which results in orders of magnitude higher heating rates than conventional oven treatments. Therefore, we analyse rock strength variations after different maximum temperatures, flame-based heating rates, and rock confinement pressures. The results show that flame treatments lead to a monotonous decrease of rock strength with temperature. This is different from oven treatments, where an initial increase of strength is typically observed, followed by a steep decrease upon further (slow) oven-heating. Thus, the weakening of sandstone and granite samples due to flame treatments indicates the feasibility of a combined mechanical-thermal drilling system. These results suggest that the new combined method enables improved rates of penetration in hard rocks while reducing the rate of drill tool wear. We also present possible implementations of this combined drilling system in the field. From field test results, advantages and limitations of the proposed new technology are presented, with an emphasis on accessing geothermal energy resources in crystalline basement rocks.

The Misgav Ladach method: a step forward in the operative technique of caesarean section.

PubMed

Poonam; Banerjee, B; Singh, S N; Raina, A

2006-01-01

Caesarean delivery remains the most common intraperitoneal surgical procedure in obstetric and gynaecologic practice. Since time immemorial there have been countless efforts to improve the technique of caesarean section. One such innovative breakthrough technique is the Misgav Ladach method of caesarean of section. The objective of this trial was to compare the intraoperative and short-term postoperative outcomes between the conventional and the Misgav-Ladach technique for caesarean section. The randomized prospective comparative study was carried out in the department of Obstetrics and Gynaecology, B.P Koirala Institute of Health Sciences, Dharan Nepal. Four hundred patients were randomized to either Misgav Ladach or the Conventional method of caesarean section. Only term pregnancies with singleton foetuses' were included whereas pregnancies with previous caesarean section were excluded from the study. The study period was from September 2001 to September 2004. There was not much difference in the demographic variables between the two groups. The age of the patients ranged between 18-40 years. The mean age of patients in Misgav Ladach and conventional group was 24.5 and 23.6 years respectively. Foetal distress was the commonest indication for caesarean section followed by non progress of labour. The mean incision to delivery interval, operating time and blood loss in the Misgav Ladach group was 1 minute 30 seconds, 16 minutes and 35 0ml as compared to 3 minutes, 28 minutes and 600 ml in the conventional group respectively. 3.5%of patients in the Misgav Ladach group showed febrile morbidity as compared to 7% in the conventional group. 19% from conventional group and only 4%from Misgav Ladach group required added analgesia. Almost equal number of patients (10-12) in each group experienced significant headache.).0.1%in the Misgav group and 5% in the Conventional group required post operative blood transfusion. Four patients from the conventional group had their wound gaped. The number of neonates requiring intensive care was sixteen (8% ) in the conventional group and 3 (1.5%) in the Misgav group.6.5% from conventional group and 2% from Misgav Ladach group required maternal intensive care admissions. Misgav-Ladach technique has been be associated with shorter operative time, quicker recovery, and lesser need for postoperative medications, when compared with traditional caesarean section. It has also been shown to be more cost-effective. A further advantage of the technique may be the shorter time taken for the delivery of the child.

Land-based lidar mapping: a new surveying technique to shed light on rapid topographic change

USGS Publications Warehouse

Collins, Brian D.; Kayen, Robert

2006-01-01

The rate of natural change in such dynamic environments as rivers and coastlines can sometimes overwhelm the monitoring capacity of conventional surveying methods. In response to this limitation, U.S. Geological Survey (USGS) scientists are pioneering new applications of light detection and ranging (lidar), a laser-based scanning technology that promises to greatly increase our ability to track rapid topographic changes and manage their impact on affected communities.

Lenticuloschisis: A "No Dissection" Technique for Lenticule Extraction in Small Incision Lenticule Extraction.

PubMed

Ganesh, Sri; Brar, Sheetal

2017-08-01

To describe a "no dissection" technique of lenticule removal in small incision lenticule extraction (SMILE). After docking and laser delivery, a microforceps is used to grasp and gently peel off the lenticule from the underlying stromal bed, without performing any dissection of the upper and lower planes of the lenticule. Prerequisites are a surgeon experienced in the conventional SMILE technique, optimized laser energy settings, and a minimum peripheral lenticule thickness of 25 to 30 µm. The interface as assessed in postoperative dilated clinical photographs was seen to be clearer with less roughness compared to the conventional dissection technique. This may potentially result in better first postoperative visual acuity and quality of vision due to less corneal tissue trauma and minimal tissue handling, thus potentially resulting in faster visual recovery. No dissection lenticule removal is a feasible and reproducible technique that may result in better immediate visual quality compared to the conventional SMILE technique. [J Refract Surg. 2017;33(8):563-566.]. Copyright 2017, SLACK Incorporated.

A Clinical Comparative Study of 3-Dimensional Accuracy between Digital and Conventional Implant Impression Techniques.

PubMed

Alsharbaty, Mohammed Hussein M; Alikhasi, Marzieh; Zarrati, Simindokht; Shamshiri, Ahmed Reza

2018-02-09

To evaluate the accuracy of a digital implant impression technique using a TRIOS 3Shape intraoral scanner (IOS) compared to conventional implant impression techniques (pick-up and transfer) in clinical situations. Thirty-six patients who had two implants (Implantium, internal connection) ranging in diameter between 3.8 and 4.8 mm in posterior regions participated in this study after signing a consent form. Thirty-six reference models (RM) were fabricated by attaching two impression copings intraorally, splinted with autopolymerizing acrylic resin, verified by sectioning through the middle of the index, and rejoined again with freshly mixed autopolymerizing acrylic resin pattern (Pattern Resin) with the brush bead method. After that, the splinted assemblies were attached to implant analogs (DANSE) and impressed with type III dental stone (Gypsum Microstone) in standard plastic die lock trays. Thirty-six working casts were fabricated for each conventional impression technique (i.e., pick-up and transfer). Thirty-six digital impressions were made with a TRIOS 3Shape IOS. Eight of the digitally scanned files were damaged; 28 digital scan files were retrieved to STL format. A coordinate-measuring machine (CMM) was used to record linear displacement measurements (x, y, and z-coordinates), interimplant distances, and angular displacements for the RMs and conventionally fabricated working casts. CATIA 3D evaluation software was used to assess the digital STL files for the same variables as the CMM measurements. CMM measurements made on the RMs and conventionally fabricated working casts were compared with 3D software measurements made on the digitally scanned files. Data were statistically analyzed using the generalized estimating equation (GEE) with an exchangeable correlation matrix and linear method, followed by the Bonferroni method for pairwise comparisons (α = 0.05). The results showed significant differences between the pick-up and digital groups in all of the measured variables (p < 0.001). Concerning the transfer and digital groups, the results were statistically significant in angular displacement (p < 0.001), distance measurements (p = 0.01), and linear displacement (p = 0.03); however, between the pick-up and transfer groups, there was no statistical significance in all of the measured variables (interimplant distance deviation, linear displacement, and angular displacement deviations). According to the results of this study, the digital implant impression technique had the least accuracy. Based on the study outcomes, distance and angulation errors associated with the intraoral digital implant impressions were too large to fabricate well-fitting restorations for partially edentulous patients. The pick-up implant impression technique was the most accurate, and the transfer technique revealed comparable accuracy to it. © 2018 by the American College of Prosthodontists.

A Fast Hartley Transform based novel optical OFDM system for VLC indoor application with constant envelope PAPR reduction technique using frequency modulation

NASA Astrophysics Data System (ADS)

Singh, Vinay Kumar; Dalal, U. D.

2017-10-01

In this research literature we present a unique optical OFDM system for Visible Light Communication (VLC) intended for indoor application which uses a non conventional transform-Fast Hartley Transform and an effective method to reduce the peak to average power ratio (PAPR) of the OFDM signal based on frequency modulation leading to a constant envelope (CE) signal. The proposed system is analyzed by a complete mathematical model and verified by the concurrent simulations results. The use of the non conventional transform makes the system computationally more desirable as it does not require the Hermitian symmetry constraint to yield real signals. The frequency modulation of the baseband signal converge random peaks into a CE signal. This leads to alleviation of the non linearity effects of the LED used in the link for electrical to optical conversion. The PAPR is reduced to 2 dB by this technique in this work. The impact of the modulation index on the performance of the system is also investigated. An optimum modulation depth of 30% gives better results. The additional phase discontinuity incurring on the demodulated signal at the receiver is also significantly reduced. A comparison of the improvement in phase discontinuity of the proposed technique of combating the PAPR with the previously known phase modulation technique is also presented in this work. Based on the channel metrics we evaluate the system performance and report an improvement of 1.2 dB at the FEC threshold. The proposed system is simple in design and computationally efficient and this can be incorporated into the present VLC system without much alteration thereby making it a cost effective solution.

Feasibility and performance of an adaptive contrast-oriented FDG PET/CT quantification technique for global disease assessment of malignant pleural mesothelioma and a brief review of the literature.

PubMed

Marin-Oyaga, Victor A; Salavati, Ali; Houshmand, Sina; Pasha, Ahmed Khurshid; Gharavi, Mohammad; Saboury, Babak; Basu, Sandip; Torigian, Drew A; Alavi, Abass

2015-01-01

Treatment of malignant pleural mesothelioma (MPM) remains very challenging. Assessment of response to treatment is necessary for modifying treatment and using new drugs. Global disease assessment (GDA) by implementing image processing methods to extract more information out of positron emission tomography (PET) images may provide reliable information. In this study we show the feasibility of this method of semi-quantification in patients with mesothelioma, and compare it with the conventional methods. We also present a review of the literature about this topic. Nineteen subjects with histologically proven MPM who had undergone fluoride-18-fluorodeoxyglucose PET/computed tomography ((18)F-FDG PET/CT) before and after treatment were included in this study. An adaptive contrast-oriented thresholding algorithm was used for the image analysis and semi-quantification. Metabolic tumor volume (MTV), maximum and mean standardized uptake volume (SUVmax, SUVmean) and total lesion glycolysis (TLG) were calculated for each region of interest. The global tumor glycolysis (GTG) was obtained by summing up all TLG. Treatment response was assessed by the European Organisation for Research and Treatment of Cancer (EORTC) criteria and the changes of GTG. Agreement between global disease assessment and conventional method was also determined. In patients with progressive disease based on EORTC criteria, GTG showed an increase of 150.7 but in patients with stable or partial response, GTG showed a decrease of 433.1. The SUVmax of patients before treatment was 5.95 (SD: 2.93) and after the treatment it increased to 6.38 (SD: 3.19). Overall concordance of conventional method with GDA method was 57%. Concordance of progression of disease based on conventional method was 44%, stable disease was 85% and partial response was 33%. Discordance was 55%, 14% and 66%. Adaptive contrast-oriented thresholding algorithm is a promising method to quantify the whole tumor glycolysis in patients with mesothelioma. We are able to assess the total metabolic lesion volume, lesion glycolysis, SUVmax, tumor SUVmean and GTG for this particular tumor. Also we were able to demonstrate the potential use of this technique in the monitoring of treatment response. More studies comparing this technique with conventional and other global disease assessment methods are needed in order to clarify its role in the assessment of treatment response and prognosis of these patients.

Experimental Study on Damage Detection in Timber Specimens Based on an Electromechanical Impedance Technique and RMSD-Based Mahalanobis Distance

PubMed Central

Wang, Dansheng; Wang, Qinghua; Wang, Hao; Zhu, Hongping

2016-01-01

In the electromechanical impedance (EMI) method, the PZT patch performs the functions of both sensor and exciter. Due to the high frequency actuation and non-model based characteristics, the EMI method can be utilized to detect incipient structural damage. In recent years EMI techniques have been widely applied to monitor the health status of concrete and steel materials, however, studies on application to timber are limited. This paper will explore the feasibility of using the EMI technique for damage detection in timber specimens. In addition, the conventional damage index, namely root mean square deviation (RMSD) is employed to evaluate the level of damage. On that basis, a new damage index, Mahalanobis distance based on RMSD, is proposed to evaluate the damage severity of timber specimens. Experimental studies are implemented to detect notch and hole damage in the timber specimens. Experimental results verify the availability and robustness of the proposed damage index and its superiority over the RMSD indexes. PMID:27782088

Experimental Study on Damage Detection in Timber Specimens Based on an Electromechanical Impedance Technique and RMSD-Based Mahalanobis Distance.

PubMed

Wang, Dansheng; Wang, Qinghua; Wang, Hao; Zhu, Hongping

2016-10-22

In the electromechanical impedance (EMI) method, the PZT patch performs the functions of both sensor and exciter. Due to the high frequency actuation and non-model based characteristics, the EMI method can be utilized to detect incipient structural damage. In recent years EMI techniques have been widely applied to monitor the health status of concrete and steel materials, however, studies on application to timber are limited. This paper will explore the feasibility of using the EMI technique for damage detection in timber specimens. In addition, the conventional damage index, namely root mean square deviation (RMSD) is employed to evaluate the level of damage. On that basis, a new damage index, Mahalanobis distance based on RMSD, is proposed to evaluate the damage severity of timber specimens. Experimental studies are implemented to detect notch and hole damage in the timber specimens. Experimental results verify the availability and robustness of the proposed damage index and its superiority over the RMSD indexes.

A TEMPLATE-BASED FABRICATION TECHNIQUE FOR SPATIALLY-DESIGNED POLYMER MICRO/NANOFIBER COMPOSITES

PubMed Central

Naik, Nisarga; Caves, Jeff; Kumar, Vivek; Chaikof, Elliot; Allen, Mark G.

2013-01-01

This paper reports a template-based technique for the fabrication of polymer micro/nanofiber composites, exercising control over the fiber dimensions and alignment. Unlike conventional spinning-based methods of fiber production, the presented approach is based on micro-transfer molding. It is a parallel processing technique capable of producing fibers with control over both in-plane and out-of-plane geometries, in addition to packing density and layout of the fibers. Collagen has been used as a test polymer to demonstrate the concept. Hollow and solid collagen fibers with various spatial layouts have been fabricated. Produced fibers have widths ranging from 2 µm to 50 µm, and fiber thicknesses ranging from 300 nm to 3 µm. Also, three-dimensionality of the process has been demonstrated by producing in-plane serpentine fibers with designed arc lengths, out-of-plane wavy fibers, fibers with focalized particle encapsulation, and porous fibers with desired periodicity and pore sizes. PMID:24533428

Use of partial dissolution techniques in geochemical exploration

USGS Publications Warehouse

Chao, T.T.

1984-01-01

Application of partial dissolution techniques to geochemical exploration has advanced from an early empirical approach to an approach based on sound geochemical principles. This advance assures a prominent future position for the use of these techniques in geochemical exploration for concealed mineral deposits. Partial dissolution techniques are classified as single dissolution or sequential multiple dissolution depending on the number of steps taken in the procedure, or as "nonselective" extraction and as "selective" extraction in terms of the relative specificity of the extraction. The choice of dissolution techniques for use in geochemical exploration is dictated by the geology of the area, the type and degree of weathering, and the expected chemical forms of the ore and of the pathfinding elements. Case histories have illustrated many instances where partial dissolution techniques exhibit advantages over conventional methods of chemical analysis used in geochemical exploration. ?? 1984.

Rectangular Microstrip Antenna with Slot Embedded Geometry

NASA Astrophysics Data System (ADS)

Ambresh, P. A.; Hadalgi, P. M.; Hunagund, P. V.; Sujata, A. A.

2014-09-01

In this paper, a novel design that improves the performance of conventional rectangular microstrip antenna is discussed. Design adopts basic techniques such as probe feeding technique with rectangular inverted patch structure as superstrate, air filled dielectric medium as substrate and slot embedded patch. Prototype of the proposed antenna has been fabricated and various antenna performance parameters such as impedance bandwidth, return loss, radiation pattern and antenna gain are considered for Electromagnetic-study. The antennas are designed for the wireless application operating in the frequency range of 3.3 GHz to 3.6 GHz, and UK based fixed satellite service application (3 GHz to 4 GHz), and are named as single inverted patch conventional rectangular microstrip antenna (SIP-CRMSA) and slots embedded inverted patch rectangular microstrip antenna (SEIP-RMSA), respectively. Measurement outcomes for SEIP-RMSA1 and SEIP-RMSA2 showed the satisfactory performance with an achievable impedance bandwidth of 260 MHz (7 %) and 250 MHz (6.72 %), with return loss (RL) of -11.06 dB and -17.98 dB, achieved gain of 8.17 dB and 5.17 dB with 10% and 8% size reduction in comparison with the conventional patch antenna.

Comparison of detection limit in fiber-based conventional, amplified, and gain-clamped cavity ring-down techniques

NASA Astrophysics Data System (ADS)

Sharma, K.; Abdul Khudus, M. I. M.; Alam, S. U.; Bhattacharya, S.; Venkitesh, D.; Brambilla, G.

2018-01-01

Relative performance and detection limit of conventional, amplified, and gain-clamped cavity ring-down techniques (CRDT) in all-fiber configurations are compared experimentally for the first time. Refractive index measurement using evanescent field in tapered fibers is used as a benchmark for the comparison. The systematic optimization of a nested-loop configuration in gain-clamped CRDT is also discussed, which is crucial for achieving a constant gain in a CRDT experiment. It is found that even though conventional CRDT has the lowest standard error in ring-down time (Δτ), the value of ring-down time (τ) is very small, thus leading to poor detection limit. Amplified CRDT provides an improvement in τ, albeit with two orders of magnitude higher Δτ due to amplifier noise. The nested-loop configuration in gain-clamped CRDT helps in reducing Δτ by an order of magnitude as compared to amplified CRDT whilst retaining the improvement in τ. A detection limit of 1 . 03 × 10-4 RIU at refractive index of 1.322 with a 3 mm long and 4.5 μm diameter tapered fiber is demonstrated with the gain-clamped CRDT.

Two-surgeon technique for liver transection using precoagulation by a soft-coagulation system and ultrasonic dissection.

PubMed

Yamada, Nobuya; Amano, Ryosuke; Kimura, Kenjiro; Murata, Akihiro; Yashiro, Masakazu; Tanaka, Sayaka; Wakasa, Kenichi; Hirakawa, Kosei

2015-01-01

A soft-coagulation system (SCS) was introduced as an effective device to reduce blood loss in hepatectomy. Here we evaluated the efficacy of a two-surgeon technique using precoagulation by an SCS and the Cavitron Ultrasonic Surgical Aspirator (CUSA) for liver transection. The 163 patients with liver tumors were divided into two groups (conventional group and two-surgeon group). Liver transection was conducted using saline-coupled bipolar electrocautery and CUSA in 102 patients (conventional group). In 61 patients (the two-surgeon group), a two-surgeon technique using precoagulation by an SCS and CUSA for liver resection was performed. The median blood loss was significantly less in the two-surgeon group compared to the conventional group (354.8 mL vs. 557.8 mL, respec tively: p = 0.0011). The postoperative hospital stay was significantly shorter in the two-surgeon group compared to the conventional group (12.7 days vs. 15.5 days, p = 0.0035). The two-surgeon technique using precoagulation by an SCS and CUSA was significantly reduced blood loss during liver transection, and associated with low morbidity and mortality. This technique may be useful for many hepatobiliary surgeons.

Novel Techniques for Pulsed Field Gradient NMR Measurements

NASA Astrophysics Data System (ADS)

Brey, William Wallace

Pulsed field gradient (PFG) techniques now find application in multiple quantum filtering and diffusion experiments as well as in magnetic resonance imaging and spatially selective spectroscopy. Conventionally, the gradient fields are produced by azimuthal and longitudinal currents on the surfaces of one or two cylinders. Using a series of planar units consisting of azimuthal and radial current elements spaced along the longitudinal axis, we have designed gradient coils having linear regions that extend axially nearly to the ends of the coil and to more than 80% of the inner radius. These designs locate the current return paths on a concentric cylinder, so the coils are called Concentric Return Path (CRP) coils. Coils having extended linear regions can be made smaller for a given sample size. Among the advantages that can accrue from using smaller coils are improved gradient strength and switching time, reduced eddy currents in the absence of shielding, and improved use of bore space. We used an approximation technique to predict the remaining eddy currents and a time-domain model of coil performance to simulate the electrical performance of the CRP coil and several reduced volume coils of more conventional design. One of the conventional coils was designed based on the time-domain performance model. A single-point acquisition technique was developed to measure the remaining eddy currents of the reduced volume coils. Adaptive sampling increases the dynamic range of the measurement. Measuring only the center of the stimulated echo removes chemical shift and B_0 inhomogeneity effects. The technique was also used to design an inverse filter to remove the eddy current effects in a larger coil set. We added pulsed field gradient and imaging capability to a 7 T commercial spectrometer to perform neuroscience and embryology research and used it in preliminary studies of binary liquid mixtures separating near a critical point. These techniques and coil designs will find application in research areas ranging from functional imaging to NMR microscopy.

Generation of Protein Crystals Using a Solution-Stirring Technique

NASA Astrophysics Data System (ADS)

Adachi, Hiroaki; Niino, Ai; Matsumura, Hiroyoshi; Takano, Kazufumi; Kinoshita, Takayoshi; Warizaya, Masaichi; Inoue, Tsuyoshi; Mori, Yusuke; Sasaki, Takatomo

2004-06-01

Crystals of bovine adenosine deaminase (ADA) were grown over a two week period in the presence of an inhibitor, whereas ADA crystals did not form using conventional crystallization methods when the inhibitor was excluded. To obtain ADA crystals in the absence of the inhibitor, a solution-stirring technique was used. The crystals obtained using this technique were found to be of high quality and were shown to have high structural resolution for X-ray diffraction analysis. The results of this study indicate that the stirring technique is a useful method for obtaining crystals of proteins that do not crystallize using conventional techniques.

Development of Sex-Trait Stereotypes Among Young Children in the United States, England, and Ireland.

ERIC Educational Resources Information Center

Best, Deborah L.; And Others

The Sex Stereotype Measure II (SSM II), a 32-item picture-story technique, was developed to assess children's knowledge of conventional, adult-defined, sex-trait stereotypes. The procedure was based on stereotype characteristics identified by college students using the Adjective Check List item pool. A second procedure, the Sex Attitude Measure…

Array-Based Discovery of Aptamer Pairs

DTIC Science & Technology

2014-12-11

affinities greatly exceeding either monovalent component. DNA aptamers are especially well-suited for such constructs, because they can be linked via...standard synthesis techniques without requiring chemical conjugation. Unfortunately, aptamer pairs are difficult to generate, primarily because...conventional selection methods preferentially yield aptamers that recognize a dominant “hot spot” epitope. Our 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND

Sentinel Lymph Node Biopsy: Quantification of Lymphedema Risk Reduction

DTIC Science & Technology

2006-10-01

dimensional internal mammary lymphoscintigraphy: implications for radiation therapy treatment planning for breast carcinoma. Int J Radiat Oncol Biol Phys...techniques based on conventional photon beams, intensity modulated photon beams and proton beams for therapy of intact breast. Radiother Oncol. Feb...Harris JR. Three-dimensional internal mammary lymphoscintigraphy: implications for radiation therapy treatment planning for breast carcinoma. Int J

Production of durable expanded perlite microspheres in a Vertical Electrical Furnace

NASA Astrophysics Data System (ADS)

Panagiotis, M.; Angelopoulos, P.; Taxiarchou, M.; Paspaliaris, I.

2016-04-01

Expanded perlite constitutes one of the most competitive insulating materials that is widely used in construction and manufacturing industry due to its unique properties combination; it is white, natural, lightweight, chemically inert, and exhibits superior insulating properties (thermal and acoustic) and fire resistance. Conventionally, perlite expansion is performed in vertical gas-fired furnaces; the conventional perlite expansion process has certain disadvantages which affect expanded products quality, thus limiting their performance and range of applications. In order to overcome the drawbacks of the conventional expansion technique, a new perlite expansion process has been designed based on a vertical electrical furnace (VEF). In the current study, fine perlite samples (-150 μm) from Milos Island, Greece, were expansed in the novel VEF and a conventional gas-fired furnace with the aim to evaluate and compare the main physical properties of the expanded products. The novel expanded perlite particles were characterised by superior properties, namely increased compression strength, competitive water and oil absorption capability, size homogeneity, spherical shape and decreased surface porosity in comparison to conventionally expanded samples.

Linewidth measurements of tunable diode lasers using heterodyne and etalon techniques

NASA Technical Reports Server (NTRS)

Reid, J.; Cassidy, D. T.; Menzies, R. T.

1982-01-01

Measurements of the linewidths of Pb-salt diode lasers operating in the 8- and 9-micron region are reported. The linewidths of the 9-micron lasers were determined by conventional heterodyne techniques, while for the 8-micron lasers a new technique based on a Fabry-Perot etalon was used. The new technique avoids the complexity and limited wavelength range of the heterodyne measurements and can be used for any tunable laser. The linewidths observed varied from 0.6 to more than 500-MHz FWHM. The linewidth was found to vary dramatically from device to device, to depend strongly on junction temperature and injection current, and to be correlated with vibrations caused by operation of a closed-cycle refrigerator.

Recent Experimental Results Related to Ejector Mode Studies of Rocket-Based Combined Cycle (RBCC) Engines

NASA Technical Reports Server (NTRS)

Cramer, J. M.; Pal, S.; Marshall, W. M.; Santoro, R. J.

2003-01-01

Contents include the folloving: 1. Motivation. Support NASA's 3d generation launch vehicle technology program. RBCC is promising candidate for 3d generation propulsion system. 2. Approach. Focus on ejector mode p3erformance (Mach 0-3). Perform testing on established flowpath geometry. Use conventional propulsion measurement techniques. Use advanced optical diagnostic techniques to measure local combustion gas properties. 3. Objectives. Gain physical understanding of detailing mixing and combustion phenomena. Establish an experimental data set for CFD code development and validation.

Single-pulse measurement of density and temperature in a turbulent, supersonic flow using UV laser spectroscopy

NASA Technical Reports Server (NTRS)

Fletcher, D. G.; Mckenzie, R. L.

1992-01-01

Nonintrusive measurements of density and temperature and their turbulent fluctuation levels have been obtained in the boundary layer of an unseeded, Mach 2 wind tunnel flow. The spectroscopic technique that was used to make the measurements is based on the combination of laser-induced oxygen fluorescence and Raman scattering by oxygen and nitrogen from the same laser pulse. Results from this demonstration experiment compare favorably with previous measurements obtained in the same facility from conventional probes and an earlier spectroscopic technique.

A stiffness derivative finite element technique for determination of crack tip stress intensity factors

NASA Technical Reports Server (NTRS)

Parks, D. M.

1974-01-01

A finite element technique for determination of elastic crack tip stress intensity factors is presented. The method, based on the energy release rate, requires no special crack tip elements. Further, the solution for only a single crack length is required, and the crack is 'advanced' by moving nodal points rather than by removing nodal tractions at the crack tip and performing a second analysis. The promising straightforward extension of the method to general three-dimensional crack configurations is presented and contrasted with the practical impossibility of conventional energy methods.

Quantum-optical coherence tomography with classical light.

PubMed

Lavoie, J; Kaltenbaek, R; Resch, K J

2009-03-02

Quantum-optical coherence tomography (Q-OCT) is an interferometric technique for axial imaging offering several advantages over conventional methods. Chirped-pulse interferometry (CPI) was recently demonstrated to exhibit all of the benefits of the quantum interferometer upon which Q-OCT is based. Here we use CPI to measure axial interferograms to profile a sample accruing the important benefits of Q-OCT, including automatic dispersion cancellation, but with 10 million times higher signal. Our technique solves the artifact problem in Q-OCT and highlights the power of classical correlation in optical imaging.

AGARD Flight Test Instrumentation Series. Volume 1, Issue 2. Basic Principles of Flight Test Instrumentation Engineering (Introduction Generale aux Principles de Base de l’Instrumentation des Essais en Vol)

DTIC Science & Technology

1994-03-01

evaluation of its anticipated value. If the program can be accomplished using conventional techniques , this should be seriously considered. Development or...the direct frequency generating principles such as, pulse tachos, turbine flowmeters, and encoders, also Doppler and laser techniques used for...CERAMIC BLOCK Figure 5.3. The basic concepts of the laser ring gyro (LRG). The principle depends upon the guidance of two beams of laser light around an

Information Gain Based Dimensionality Selection for Classifying Text Documents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumidu Wijayasekara; Milos Manic; Miles McQueen

2013-06-01

Selecting the optimal dimensions for various knowledge extraction applications is an essential component of data mining. Dimensionality selection techniques are utilized in classification applications to increase the classification accuracy and reduce the computational complexity. In text classification, where the dimensionality of the dataset is extremely high, dimensionality selection is even more important. This paper presents a novel, genetic algorithm based methodology, for dimensionality selection in text mining applications that utilizes information gain. The presented methodology uses information gain of each dimension to change the mutation probability of chromosomes dynamically. Since the information gain is calculated a priori, the computational complexitymore » is not affected. The presented method was tested on a specific text classification problem and compared with conventional genetic algorithm based dimensionality selection. The results show an improvement of 3% in the true positives and 1.6% in the true negatives over conventional dimensionality selection methods.« less

Design, fabrication, and experimental characterization of plasmonic photoconductive terahertz emitters.

PubMed

Berry, Christopher; Hashemi, Mohammad Reza; Unlu, Mehmet; Jarrahi, Mona

2013-07-08

In this video article we present a detailed demonstration of a highly efficient method for generating terahertz waves. Our technique is based on photoconduction, which has been one of the most commonly used techniques for terahertz generation (1-8). Terahertz generation in a photoconductive emitter is achieved by pumping an ultrafast photoconductor with a pulsed or heterodyned laser illumination. The induced photocurrent, which follows the envelope of the pump laser, is routed to a terahertz radiating antenna connected to the photoconductor contact electrodes to generate terahertz radiation. Although the quantum efficiency of a photoconductive emitter can theoretically reach 100%, the relatively long transport path lengths of photo-generated carriers to the contact electrodes of conventional photoconductors have severely limited their quantum efficiency. Additionally, the carrier screening effect and thermal breakdown strictly limit the maximum output power of conventional photoconductive terahertz sources. To address the quantum efficiency limitations of conventional photoconductive terahertz emitters, we have developed a new photoconductive emitter concept which incorporates a plasmonic contact electrode configuration to offer high quantum-efficiency and ultrafast operation simultaneously. By using nano-scale plasmonic contact electrodes, we significantly reduce the average photo-generated carrier transport path to photoconductor contact electrodes compared to conventional photoconductors (9). Our method also allows increasing photoconductor active area without a considerable increase in the capacitive loading to the antenna, boosting the maximum terahertz radiation power by preventing the carrier screening effect and thermal breakdown at high optical pump powers. By incorporating plasmonic contact electrodes, we demonstrate enhancing the optical-to-terahertz power conversion efficiency of a conventional photoconductive terahertz emitter by a factor of 50 (10).

Electron tomography of whole cultured cells using novel transmission electron imaging technique.

PubMed

Okumura, Taiga; Shoji, Minami; Hisada, Akiko; Ominami, Yusuke; Ito, Sukehiro; Ushiki, Tatsuo; Nakajima, Masato; Ohshima, Takashi

2018-01-01

Since a three-dimensional (3D) cellular ultrastructure is significant for biological functions, it has been investigated using various electron microscopic techniques. Although transmission electron microscopy (TEM)-based techniques are traditionally used, cells must be embedded in resin and sliced into ultrathin sections in sample preparation processes. Block-face observation using a scanning electron microscope (SEM) has also been recently applied to 3D observation of cellular components, but this is a destructive inspection and does not allow re-examination. Therefore, we developed electron tomography using a transmission electron imaging technique called Plate-TEM. With Plate-TEM, the cells cultured directly on a scintillator plate are inserted into a conventional SEM equipped with a Plate-TEM observation system, and their internal structures are observed by detecting scintillation light produced by electrons passing through the cells. This technology has the following four advantages. First, the cells cultured on the plate can be observed at electron-microscopic resolution since they remain on the plate. Second, both surface and internal information can be obtained simultaneously by using electron- and photo-detectors, respectively, because a Plate-TEM detector is installed in an SEM. Third, the cells on the scintillator plate can also be inspected using light microscopy because the plate has transparent features. Finally, correlative observation with other techniques, such as conventional TEM, is possible after Plate-TEM observation because Plate-TEM is a non-destructive analysis technique. We also designed a sample stage to tilt the samples for tomography with Plate-TEM, by which 3D organization of cellular structures can be visualized as a whole cell. In the present study, Mm2T cells were investigated using our tomography system, resulting in 3D visualization of cell organelles such as mitochondria, lipid droplets, and microvilli. Correlative observations with various imaging techniques were also conducted by successive observations with light microscopy, SEM, Plate-TEM, and conventional TEM. Consequently, the Plate-TEM tomography technique encourages understanding of cellular structures at high resolution, which can contribute to cellular biological research. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prelaunch optical characterization of the Laser Geodynamic Satellite (LAGEOS 2)

NASA Technical Reports Server (NTRS)

Minott, Peter O.; Zagwodzki, Thomas W.; Varghese, Thomas; Seldon, Michael

1993-01-01

The optical range correction (the distance between the apparent retroreflective skin of the satellite and the center of mass) of the LAGEOS 2 was determined using computer analysis of theoretical and experimentally measured far field diffraction patterns, and with short pulse lasers using both streak camera-based range receivers and more conventional PMT-based range receivers. The three measurement techniques yielded range correction values from 248 to 253 millimeters dependent on laser wavelength, pulsewidth, and polarization, location of the receiver in the far field diffraction pattern and detection technique (peak, half maximum, centroid, or constant fraction). The Lidar cross section of LAGEOS 2 was measured at 4 to 10 million square meters, comparable to the LAGEOS 1.

Magnetic resonance imaging based functional imaging in paediatric oncology.

PubMed

Manias, Karen A; Gill, Simrandip K; MacPherson, Lesley; Foster, Katharine; Oates, Adam; Peet, Andrew C

2017-02-01

Imaging is central to management of solid tumours in children. Conventional magnetic resonance imaging (MRI) is the standard imaging modality for tumours of the central nervous system (CNS) and limbs and is increasingly used in the abdomen. It provides excellent structural detail, but imparts limited information about tumour type, aggressiveness, metastatic potential or early treatment response. MRI based functional imaging techniques, such as magnetic resonance spectroscopy, diffusion and perfusion weighted imaging, probe tissue properties to provide clinically important information about metabolites, structure and blood flow. This review describes the role of and evidence behind these functional imaging techniques in paediatric oncology and implications for integrating them into routine clinical practice. Copyright © 2016 Elsevier Ltd. All rights reserved.

Laser tissue welding in ophthalmic surgery.

PubMed

Rossi, Francesca; Matteini, Paolo; Ratto, Fulvio; Menabuoni, Luca; Lenzetti, Ivo; Pini, Roberto

2008-09-01

Laser welding of ocular tissues is an alternative technique or adjunct to conventional suturing in ophthalmic surgery. It is based on the photothermal interaction of laser light with the main components of the extracellular matrix of connective tissues. The advantages of the welding procedure with respect to standard suturing and stapling are reduced operation times, lesser inflammation, faster healing and increased ability to induce tissue regeneration. The procedure we set up is based on the use of an infrared diode laser in association with the topical application of the chromophore Indocyanine Green. Laser light may be delivered either continuously or in pulses, thus identifying two different techniques that have been applied clinically in various types of transplants of the cornea.

Verification and Validation of Autonomy Software at NASA

NASA Technical Reports Server (NTRS)

Pecheur, Charles

2000-01-01

Autonomous software holds the promise of new operation possibilities, easier design and development and lower operating costs. However, as those system close control loops and arbitrate resources on board with specialized reasoning, the range of possible situations becomes very large and uncontrollable from the outside, making conventional scenario-based testing very inefficient. Analytic verification and validation (V&V) techniques, and model checking in particular, can provide significant help for designing autonomous systems in a more efficient and reliable manner, by providing a better coverage and allowing early error detection. This article discusses the general issue of V&V of autonomy software, with an emphasis towards model-based autonomy, model-checking techniques and concrete experiments at NASA.

Verification and Validation of Autonomy Software at NASA

NASA Technical Reports Server (NTRS)

Pecheur, Charles

2000-01-01

Autonomous software holds the promise of new operation possibilities, easier design and development, and lower operating costs. However, as those system close control loops and arbitrate resources on-board with specialized reasoning, the range of possible situations becomes very large and uncontrollable from the outside, making conventional scenario-based testing very inefficient. Analytic verification and validation (V&V) techniques, and model checking in particular, can provide significant help for designing autonomous systems in a more efficient and reliable manner, by providing a better coverage and allowing early error detection. This article discusses the general issue of V&V of autonomy software, with an emphasis towards model-based autonomy, model-checking techniques, and concrete experiments at NASA.

Comparison on extraction yield of sennoside A and sennoside B from senna (Cassia angustifolia) using conventional and non conventional extraction techniques and their quantification using a validated HPLC-PDA detection method.

PubMed

Dhanani, Tushar; Singh, Raghuraj; Reddy, Nagaraja; Trivedi, A; Kumar, Satyanshu

2017-05-01

Senna is an important medicinal plant and is used in many Ayurvedic formulations. Dianthraquinone glucosides are the main bioactive phytochemicals present in leaves and pods of senna. The extraction efficiency in terms of yield and composition of the extract of senna prepared using both conventional (cold percolation at room temperature and refluxing) and non conventional (ultrasound and microwave assisted solvent extraction as well as supercritical fluid extraction) techniques were compared in the present study. Also a rapid reverse phase HPLC-PDA detection method was developed and validated for the simultaneous determination of sennoside A and sennoside B in the different extracts of senna leaves. Ultrasound and microwave assisted solvent extraction techniques were more effective in terms of yield and composition of the extracts compared to cold percolation at room temperature and refluxing methods of extraction.

Manufacturing the Gas Diffusion Layer for PEM Fuel Cell Using a Novel 3D Printing Technique and Critical Assessment of the Challenges Encountered

PubMed Central

Singamneni, Sarat; Ramos, Maximiano; Al-Jumaily, Ahmed M

2017-01-01

The conventional gas diffusion layer (GDL) of polymer electrolyte membrane (PEM) fuel cells incorporates a carbon-based substrate, which suffers from electrochemical oxidation as well as mechanical degradation, resulting in reduced durability and performance. In addition, it involves a complex manufacturing process to produce it. The proposed technique aims to resolve both these issues by an advanced 3D printing technique, namely selective laser sintering (SLS). In the proposed work, polyamide (PA) is used as the base powder and titanium metal powder is added at an optimised level to enhance the electrical conductivity, thermal, and mechanical properties. The application of selective laser sintering to fabricate a robust gas diffusion substrate for PEM fuel cell applications is quite novel and is attempted here for the first time. PMID:28773156

Manufacturing the Gas Diffusion Layer for PEM Fuel Cell Using a Novel 3D Printing Technique and Critical Assessment of the Challenges Encountered.

PubMed

Jayakumar, Arunkumar; Singamneni, Sarat; Ramos, Maximiano; Al-Jumaily, Ahmed M; Pethaiah, Sethu Sundar

2017-07-14

The conventional gas diffusion layer (GDL) of polymer electrolyte membrane (PEM) fuel cells incorporates a carbon-based substrate, which suffers from electrochemical oxidation as well as mechanical degradation, resulting in reduced durability and performance. In addition, it involves a complex manufacturing process to produce it. The proposed technique aims to resolve both these issues by an advanced 3D printing technique, namely selective laser sintering (SLS). In the proposed work, polyamide (PA) is used as the base powder and titanium metal powder is added at an optimised level to enhance the electrical conductivity, thermal, and mechanical properties. The application of selective laser sintering to fabricate a robust gas diffusion substrate for PEM fuel cell applications is quite novel and is attempted here for the first time.

A fast response, low heat generating activation method for LHe level sensors

NASA Astrophysics Data System (ADS)

Choudhury, Anup; Sahu, Santosh; Kanjilal, Dinakar

2018-06-01

A superconducting liquid helium (LHe) level sensor of length 300 mm has been fabricated based on the principle of differential heat transfer characteristic in helium gas compared to that in liquid. The sensor wire used has a diameter of 38 μm, and the wire was obtained from a pack of multifilament wires. A full thermo-electrical characterisation of the sensor was carried out in a dedicated setup. Its dynamic thermal response was also studied to understand its timing characteristics at different liquid levels and excitation currents. Based on the sensor characterisation, a new level measurement technique is evaluated which can reduce the heat load going to LHe during sensor activation without compromising on its sensitivity or accuracy. The timing response with this technique will make the level detection faster compared to the conventional techniques.

Evaluation of Clipping Based Iterative PAPR Reduction Techniques for FBMC Systems

PubMed Central

Kollár, Zsolt

2014-01-01

This paper investigates filter bankmulticarrier (FBMC), a multicarrier modulation technique exhibiting an extremely low adjacent channel leakage ratio (ACLR) compared to conventional orthogonal frequency division multiplexing (OFDM) technique. The low ACLR of the transmitted FBMC signal makes it especially favorable in cognitive radio applications, where strict requirements are posed on out-of-band radiation. Large dynamic range resulting in high peak-to-average power ratio (PAPR) is characteristic of all sorts of multicarrier signals. The advantageous spectral properties of the high-PAPR FBMC signal are significantly degraded if nonlinearities are present in the transceiver chain. Spectral regrowth may appear, causing harmful interference in the neighboring frequency bands. This paper presents novel clipping based PAPR reduction techniques, evaluated and compared by simulations and measurements, with an emphasis on spectral aspects. The paper gives an overall comparison of PAPR reduction techniques, focusing on the reduction of the dynamic range of FBMC signals without increasing out-of-band radiation. An overview is presented on transmitter oriented techniques employing baseband clipping, which can maintain the system performance with a desired bit error rate (BER). PMID:24558338

Preoperative planning of left-sided valve surgery with 3D computed tomography reconstruction models: sternotomy or a minimally invasive approach?

PubMed

Heuts, Samuel; Maessen, Jos G; Sardari Nia, Peyman

2016-05-01

With the emergence of a new concept aimed at individualization of patient care, the focus will shift from whether a minimally invasive procedure is better than conventional treatment, to the question of which patients will benefit most from which technique? The superiority of minimally invasive valve surgery (MIVS) has not yet been proved. We believe that through better patient selection advantages of this technique can become more pronounced. In our current study, we evaluate the feasibility of 3D computed tomography (CT) imaging reconstruction in the preoperative planning of patients referred for MIVS. We retrospectively analysed all consecutive patients who were referred for minimally invasive mitral valve surgery (MIMVS) and minimally invasive aortic valve replacement (MIAVR) to a single surgeon in a tertiary referral centre for MIVS between March 2014 and 2015. Prospective preoperative planning was done for all patients and was based on evaluations by a multidisciplinary heart-team, an echocardiography, conventional CT images and 3D CT reconstruction models. A total of 39 patients were included in our study; 16 for mitral valve surgery (MVS) and 23 patients for aortic valve replacement (AVR). Eleven patients (69%) within the MVS group underwent MIMVS. Five patients (31%) underwent conventional MVS. Findings leading to exclusion for MIMVS were a tortuous or slender femoro-iliac tract, calcification of the aortic bifurcation, aortic elongation and pericardial calcifications. Furthermore, 2 patients had a change of operative strategy based on preoperative planning. Seventeen (74%) patients in the AVR group underwent MIAVR. Six patients (26%) underwent conventional AVR. Indications for conventional AVR instead of MIAVR were an elongated ascending aorta, ascending aortic calcification and ascending aortic dilatation. One patient (6%) in the MIAVR group was converted to a sternotomy due to excessive intraoperative bleeding. Two mortalities were reported during conventional MVS. There were no mortalities reported in the MIMVS, MIAVR or conventional AVR group. Preoperative planning of minimally invasive left-sided valve surgery with 3D CT reconstruction models is a useful and feasible method to determine operative strategy and exclude patients ineligible for a minimally invasive approach, thus potentially preventing complications. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

General aviation internal combustion engine research programs at NASA-Lewis Research Center

NASA Technical Reports Server (NTRS)

Willis, E. A.

1978-01-01

An update is presented of non-turbine general aviation engine programs underway at the NASA-Lewis Research Center in Cleveland, Ohio. The program encompasses conventional, lightweight diesel and rotary engines. Its three major thrusts are: (a) reduced SFC's; (b) improved fuels tolerance; and (c) reducing emissions. Current and planned future programs in such areas as lean operation, improved fuel management, advanced cooling techniques and advanced engine concepts, are described. These are expected to lay the technology base, by the mid to late 1980's, for engines whose life cycle fuel costs are 30 to 50% lower than today's conventional engines.

Extraction of kiwi seed oil: Soxhlet versus four different non-conventional techniques.

PubMed

Cravotto, Giancarlo; Bicchi, Carlo; Mantegna, Stefano; Binello, Arianna; Tomao, Valerie; Chemat, Farid

2011-06-01

Kiwi seed oil has a nutritionally interesting fatty acid profile, but a rather low oxidative stability, which requires careful extraction procedures and adequate packaging and storage. For these reasons and with the aim to achieve process intensification with shorter extraction time, lower energy consumption and higher yields, four different non-conventional techniques were experimented. Kiwi seeds were extracted in hexane using classic Soxhlet as well as under power ultrasound (US), microwaves (MWs; closed vessel) and MW-integrated Soxhlet. Supercritical CO₂ was also employed and compared to the other techniques in term of yield, extraction time, fatty acid profiles and organoleptic properties. All these non-conventional techniques are fast, effective and safe. A sensory evaluation test showed the presence of off-flavours in oil samples extracted by Soxhlet and US, an indicator of partial degradation.

Improved accuracy of markerless motion tracking on bone suppression images: preliminary study for image-guided radiation therapy (IGRT)

NASA Astrophysics Data System (ADS)

Tanaka, Rie; Sanada, Shigeru; Sakuta, Keita; Kawashima, Hiroki

2015-05-01

The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images obtained by the dual-energy subtraction technique. This study was performed to evaluate the usefulness of bone suppression image processing in image-guided radiation therapy. We demonstrated the improved accuracy of markerless motion tracking on bone suppression images. Chest fluoroscopic images of nine patients with lung nodules during respiration were obtained using a flat-panel detector system (120 kV, 0.1 mAs/pulse, 5 fps). Commercial bone suppression image processing software was applied to the fluoroscopic images to create corresponding bone suppression images. Regions of interest were manually located on lung nodules and automatic target tracking was conducted based on the template matching technique. To evaluate the accuracy of target tracking, the maximum tracking error in the resulting images was compared with that of conventional fluoroscopic images. The tracking errors were decreased by half in eight of nine cases. The average maximum tracking errors in bone suppression and conventional fluoroscopic images were 1.3   ±   1.0 and 3.3   ±   3.3 mm, respectively. The bone suppression technique was especially effective in the lower lung area where pulmonary vessels, bronchi, and ribs showed complex movements. The bone suppression technique improved tracking accuracy without special equipment and implantation of fiducial markers, and with only additional small dose to the patient. Bone suppression fluoroscopy is a potential measure for respiratory displacement of the target. This paper was presented at RSNA 2013 and was carried out at Kanazawa University, JAPAN.

Improving Simulated Annealing by Recasting it as a Non-Cooperative Game

NASA Technical Reports Server (NTRS)

Wolpert, David; Bandari, Esfandiar; Tumer, Kagan

2001-01-01

The game-theoretic field of COllective INtelligence (COIN) concerns the design of computer-based players engaged in a non-cooperative game so that as those players pursue their self-interests, a pre-specified global goal for the collective computational system is achieved "as a side-effect". Previous implementations of COIN algorithms have outperformed conventional techniques by up to several orders of magnitude, on domains ranging from telecommunications control to optimization in congestion problems. Recent mathematical developments have revealed that these previously developed game-theory-motivated algorithms were based on only two of the three factors determining performance. Consideration of only the third factor would instead lead to conventional optimization techniques like simulated annealing that have little to do with non-cooperative games. In this paper we present an algorithm based on all three terms at once. This algorithm can be viewed as a way to modify simulated annealing by recasting it as a non-cooperative game, with each variable replaced by a player. This recasting allows us to leverage the intelligent behavior of the individual players to substantially improve the exploration step of the simulated annealing. Experiments are presented demonstrating that this recasting improves simulated annealing by several orders of magnitude for spin glass relaxation and bin-packing.

Social Image Tag Ranking by Two-View Learning

NASA Astrophysics Data System (ADS)

Zhuang, Jinfeng; Hoi, Steven C. H.

Tags play a central role in text-based social image retrieval and browsing. However, the tags annotated by web users could be noisy, irrelevant, and often incomplete for describing the image contents, which may severely deteriorate the performance of text-based image retrieval models. In order to solve this problem, researchers have proposed techniques to rank the annotated tags of a social image according to their relevance to the visual content of the image. In this paper, we aim to overcome the challenge of social image tag ranking for a corpus of social images with rich user-generated tags by proposing a novel two-view learning approach. It can effectively exploit both textual and visual contents of social images to discover the complicated relationship between tags and images. Unlike the conventional learning approaches that usually assumes some parametric models, our method is completely data-driven and makes no assumption about the underlying models, making the proposed solution practically more effective. We formulate our method as an optimization task and present an efficient algorithm to solve it. To evaluate the efficacy of our method, we conducted an extensive set of experiments by applying our technique to both text-based social image retrieval and automatic image annotation tasks. Our empirical results showed that the proposed method can be more effective than the conventional approaches.

Laser Surgery of Soft Tissue in Orthodontics: Review of the Clinical Trials.

PubMed

Seifi, Massoud; Matini, Negin-Sadat

2017-01-01

Introduction: Recently, a wide variety of procedures have been done by laser application in orthodontics. Apart from the mentioned range of various treatments, laser has become a tool for many soft tissue surgeries as an alternative to conventional scalpel-based technique during orthodontic treatments in the management of soft tissue. Due to scarce information in the latter subject, this study was designed in order to include clinical trials that included soft tissue ablation by laser in orthodontics. Methods: Literature was searched based on PubMed and Google Scholar databases in 5 years (2010-2015) with English language restriction and clinical trial design. Studies that performed soft tissue application of laser during orthodontic treatment were extracted by the authors. Results: Only eight studies met the inclusion criteria. No significant difference was found between laser ablation and conventional scalpel technique in the matter of treatment outcome. However, few issues remained to clarify the differences in the mentioned procedures. Conclusion: Laser performance can be recommended in case of preceding less bleeding and discomfort during surgical procedure. There are still quandaries among clinical application of scalpel-based surgery in aesthetic region with bracket-bonded teeth. Precaution and knowledge regarding the characteristics of laser beam such as wavelength, frequency, power and timing is extremely needed.

Laser Surgery of Soft Tissue in Orthodontics: Review of the Clinical Trials

PubMed Central

Seifi, Massoud; Matini, Negin-Sadat

2017-01-01

Introduction: Recently, a wide variety of procedures have been done by laser application in orthodontics. Apart from the mentioned range of various treatments, laser has become a tool for many soft tissue surgeries as an alternative to conventional scalpel-based technique during orthodontic treatments in the management of soft tissue. Due to scarce information in the latter subject, this study was designed in order to include clinical trials that included soft tissue ablation by laser in orthodontics. Methods: Literature was searched based on PubMed and Google Scholar databases in 5 years (2010-2015) with English language restriction and clinical trial design. Studies that performed soft tissue application of laser during orthodontic treatment were extracted by the authors. Results: Only eight studies met the inclusion criteria. No significant difference was found between laser ablation and conventional scalpel technique in the matter of treatment outcome. However, few issues remained to clarify the differences in the mentioned procedures. Conclusion: Laser performance can be recommended in case of preceding less bleeding and discomfort during surgical procedure. There are still quandaries among clinical application of scalpel-based surgery in aesthetic region with bracket-bonded teeth. Precaution and knowledge regarding the characteristics of laser beam such as wavelength, frequency, power and timing is extremely needed. PMID:29263776

Local defect resonance for sensitive non-destructive testing

NASA Astrophysics Data System (ADS)

Adebahr, W.; Solodov, I.; Rahammer, M.; Gulnizkij, N.; Kreutzbruck, M.

2016-02-01

Ultrasonic wave-defect interaction is a background of ultrasound activated techniques for imaging and non-destructive testing (NDT) of materials and industrial components. The interaction, primarily, results in acoustic response of a defect which provides attenuation and scattering of ultrasound used as an indicator of defects in conventional ultrasonic NDT. The derivative ultrasonic-induced effects include e.g. nonlinear, thermal, acousto-optic, etc. responses also applied for NDT and defect imaging. These secondary effects are normally relatively inefficient so that the corresponding NDT techniques require an elevated acoustic power and stand out from conventional ultrasonic NDT counterparts for their specific instrumentation particularly adapted to high-power ultrasonic. In this paper, a consistent way to enhance ultrasonic, optical and thermal defect responses and thus to reduce an ultrasonic power required is suggested by using selective ultrasonic activation of defects based on the concept of local defect resonance (LDR). A strong increase in vibration amplitude at LDR enables to reliably detect and visualize the defect as soon as the driving ultrasonic frequency is matched to the LDR frequency. This also provides a high frequency selectivity of the LDR-based imaging, i.e. an opportunity of detecting a certain defect among a multitude of other defects in material. Some examples are shown how to use LDR in non-destructive testing techniques, like vibrometry, ultrasonic thermography and shearography in order to enhance the sensitivity of defect visualization.

In vivo evaluation of inter-operator reproducibility of digital dental and conventional impression techniques.

PubMed

Kamimura, Emi; Tanaka, Shinpei; Takaba, Masayuki; Tachi, Keita; Baba, Kazuyoshi

2017-01-01

The aim of this study was to evaluate and compare the inter-operator reproducibility of three-dimensional (3D) images of teeth captured by a digital impression technique to a conventional impression technique in vivo. Twelve participants with complete natural dentition were included in this study. A digital impression of the mandibular molars of these participants was made by two operators with different levels of clinical experience, 3 or 16 years, using an intra-oral scanner (Lava COS, 3M ESPE). A silicone impression also was made by the same operators using the double mix impression technique (Imprint3, 3M ESPE). Stereolithography (STL) data were directly exported from the Lava COS system, while STL data of a plaster model made from silicone impression were captured by a three-dimensional (3D) laboratory scanner (D810, 3shape). The STL datasets recorded by two different operators were compared using 3D evaluation software and superimposed using the best-fit-algorithm method (least-squares method, PolyWorks, InnovMetric Software) for each impression technique. Inter-operator reproducibility as evaluated by average discrepancies of corresponding 3D data was compared between the two techniques (Wilcoxon signed-rank test). The visual inspection of superimposed datasets revealed that discrepancies between repeated digital impression were smaller than observed with silicone impression. Confirmation was forthcoming from statistical analysis revealing significantly smaller average inter-operator reproducibility using a digital impression technique (0.014± 0.02 mm) than when using a conventional impression technique (0.023 ± 0.01 mm). The results of this in vivo study suggest that inter-operator reproducibility with a digital impression technique may be better than that of a conventional impression technique and is independent of the clinical experience of the operator.

Green extraction of grape skin phenolics by using deep eutectic solvents.

PubMed

Cvjetko Bubalo, Marina; Ćurko, Natka; Tomašević, Marina; Kovačević Ganić, Karin; Radojčić Redovniković, Ivana

2016-06-01

Conventional extraction techniques for plant phenolics are usually associated with high organic solvent consumption and long extraction times. In order to establish an environmentally friendly extraction method for grape skin phenolics, deep eutectic solvents (DES) as a green alternative to conventional solvents coupled with highly efficient microwave-assisted and ultrasound-assisted extraction methods (MAE and UAE, respectively) have been considered. Initially, screening of five different DES for proposed extraction was performed and choline chloride-based DES containing oxalic acid as a hydrogen bond donor with 25% of water was selected as the most promising one, resulting in more effective extraction of grape skin phenolic compounds compared to conventional solvents. Additionally, in our study, UAE proved to be the best extraction method with extraction efficiency superior to both MAE and conventional extraction method. The knowledge acquired in this study will contribute to further DES implementation in extraction of biologically active compounds from various plant sources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Radiation shielding design of a new tomotherapy facility.

PubMed

Zacarias, Albert; Balog, John; Mills, Michael

2006-10-01

It is expected that intensity modulated radiation therapy (IMRT) and image guided radiation therapy (IGRT) will replace a large portion of radiation therapy treatments currently performed with conventional MLC-based 3D conformal techniques. IGRT may become the standard of treatment in the future for prostate and head and neck cancer. Many established facilities may convert existing vaults to perform this treatment method using new or upgraded equipment. In the future, more facilities undoubtedly will be considering de novo designs for their treatment vaults. A reevaluation of the design principles used in conventional vault design is of benefit to those considering this approach with a new tomotherapy facility. This is made more imperative as the design of the TomoTherapy system is unique in several aspects and does not fit well into the formalism of NCRP 49 for a conventional linear accelerator.

Bioactive calcium pyrophosphate glasses and glass-ceramics.

PubMed

Kasuga, Toshihiro

2005-01-01

Calcium phosphate glass-based materials in the pyrophosphate region are briefly reviewed. Calcium pyrophosphate glasses can be prepared by including a small amount of TiO(2) (

Techniques for Submitting Successful Proposals for SHAPE America National Conventions

ERIC Educational Resources Information Center

Stevens-Smith, Deborah

2016-01-01

This article covers the basic components of the submission process before submitting a proposal for the SHAPE America national convention. The article discusses various techniques specific to the process, including the unique discipline areas. Other issues addressed include an understanding of the SHAPE America review process and how it works,…

Design of a practical model-observer-based image quality assessment method for x-ray computed tomography imaging systems

PubMed Central

Tseng, Hsin-Wu; Fan, Jiahua; Kupinski, Matthew A.

2016-01-01

Abstract. The use of a channelization mechanism on model observers not only makes mimicking human visual behavior possible, but also reduces the amount of image data needed to estimate the model observer parameters. The channelized Hotelling observer (CHO) and channelized scanning linear observer (CSLO) have recently been used to assess CT image quality for detection tasks and combined detection/estimation tasks, respectively. Although the use of channels substantially reduces the amount of data required to compute image quality, the number of scans required for CT imaging is still not practical for routine use. It is our desire to further reduce the number of scans required to make CHO or CSLO an image quality tool for routine and frequent system validations and evaluations. This work explores different data-reduction schemes and designs an approach that requires only a few CT scans. Three different kinds of approaches are included in this study: a conventional CHO/CSLO technique with a large sample size, a conventional CHO/CSLO technique with fewer samples, and an approach that we will show requires fewer samples to mimic conventional performance with a large sample size. The mean value and standard deviation of areas under ROC/EROC curve were estimated using the well-validated shuffle approach. The results indicate that an 80% data reduction can be achieved without loss of accuracy. This substantial data reduction is a step toward a practical tool for routine-task-based QA/QC CT system assessment. PMID:27493982

Training Deep Spiking Neural Networks Using Backpropagation.

PubMed

Lee, Jun Haeng; Delbruck, Tobi; Pfeiffer, Michael

2016-01-01

Deep spiking neural networks (SNNs) hold the potential for improving the latency and energy efficiency of deep neural networks through data-driven event-based computation. However, training such networks is difficult due to the non-differentiable nature of spike events. In this paper, we introduce a novel technique, which treats the membrane potentials of spiking neurons as differentiable signals, where discontinuities at spike times are considered as noise. This enables an error backpropagation mechanism for deep SNNs that follows the same principles as in conventional deep networks, but works directly on spike signals and membrane potentials. Compared with previous methods relying on indirect training and conversion, our technique has the potential to capture the statistics of spikes more precisely. We evaluate the proposed framework on artificially generated events from the original MNIST handwritten digit benchmark, and also on the N-MNIST benchmark recorded with an event-based dynamic vision sensor, in which the proposed method reduces the error rate by a factor of more than three compared to the best previous SNN, and also achieves a higher accuracy than a conventional convolutional neural network (CNN) trained and tested on the same data. We demonstrate in the context of the MNIST task that thanks to their event-driven operation, deep SNNs (both fully connected and convolutional) trained with our method achieve accuracy equivalent with conventional neural networks. In the N-MNIST example, equivalent accuracy is achieved with about five times fewer computational operations.

Comparative study between manual injection intraosseous anesthesia and conventional oral anesthesia

PubMed Central

Ata-Ali, Javier; Oltra-Moscardó, María J.; Peñarrocha-Diago, María; Peñarrocha, Miguel

2012-01-01

Objective: To compare intraosseous anesthesia (IA) with the conventional oral anesthesia techniques. Materials and methods: A simple-blind, prospective clinical study was carried out. Each patient underwent two anesthetic techniques: conventional (local infiltration and locoregional anesthetic block) and intraosseous, for res-pective dental operations. In order to allow comparison of IA versus conventional anesthesia, the two operations were similar and affected the same two teeth in opposite quadrants. Results: A total of 200 oral anesthetic procedures were carried out in 100 patients. The mean patient age was 28.6±9.92 years. Fifty-five vestibular infiltrations and 45 mandibular blocks were performed. All patients were also subjected to IA. The type of intervention (conservative or endodontic) exerted no significant influence (p=0.58 and p=0.62, respectively). The latency period was 8.52±2.44 minutes for the conventional techniques and 0.89±0.73 minutes for IA – the difference being statistically significant (p<0.05). Regarding patient anesthesia sensation, the infiltrative techniques lasted a maximum of one hour, the inferior alveolar nerve blocks lasted between 1-3 hours, and IA lasted only 2.5 minutes – the differences being statistically significant (p≤0.0000, Φ=0.29). Anesthetic success was recorded in 89% of the conventional procedures and in 78% of the IA. Most patients preferred IA (61%) (p=0.0032). Conclusions: The two anesthetic procedures have been compared for latency, duration of anesthetic effect, anesthetic success rate and patient preference. Intraosseous anesthesia has been shown to be a technique to be taken into account when planning conservative and endodontic treatments. Key words: Anesthesia, intraosseous, oral anesthesia, Stabident®, infiltrative, mandibular block. PMID:22143700

Development of a HIV-1 Virus Detection System Based on Nanotechnology.

PubMed

Lee, Jin-Ho; Oh, Byung-Keun; Choi, Jeong-Woo

2015-04-27

Development of a sensitive and selective detection system for pathogenic viral agents is essential for medical healthcare from diagnostics to therapeutics. However, conventional detection systems are time consuming, resource-intensive and tedious to perform. Hence, the demand for sensitive and selective detection system for virus are highly increasing. To attain this aim, different aspects and techniques have been applied to develop virus sensor with improved sensitivity and selectivity. Here, among those aspects and techniques, this article reviews HIV virus particle detection systems incorporated with nanotechnology to enhance the sensitivity. This review mainly focused on four different detection system including vertically configured electrical detection based on scanning tunneling microscopy (STM), electrochemical detection based on direct electron transfer in virus, optical detection system based on localized surface plasmon resonance (LSPR) and surface enhanced Raman spectroscopy (SERS) using plasmonic nanoparticle.

Systemic inflammatory response after endoscopic (TEP) vs Shouldice groin hernia repair.

PubMed

Schwab, R; Eissele, S; Brückner, U B; Gebhard, F; Becker, H P

2004-08-01

Endoscopic techniques are commonly used for many different types of surgery. It is claimed that videoendoscopic procedures have the advantage of being less traumatic and of offering higher postoperative patient comfort than conventional open techniques. The extent of tissue trauma can be evaluated on the basis of the inflammatory response observed in the wake of surgery. Available studies that have compared endoscopic and conventional techniques suggest that endoscopic cholecystectomy, laparoscopic colorectal resection, and thoracoscopic pulmonary resection have immunologic advantages over conventional approaches. The objective of this prospective study was to determine whether endoscopic hernia repair techniques are also preferable to conventional procedures and to what extent the anesthetic technique (local or general anesthesia) influences the postoperative inflammatory response. For this purpose, biochemical monitoring of cytokine activity [C-reactive protein (CRP), prostaglandin F1alpha (PGF1alpha), neopterin, interleukin-6 (IL-6)] was done prospectively in 101 patients [totally extraperitoneal approach (TEP) n=32, unilateral n=12, bilateral n=20; Shouldice n=69, local anesthesia (LA) n=23, general anesthesia (GA) n=46] before and until 3 days after surgery. The parameters IL-6 and PGF1alpha suggested that the immune trauma immediately after surgery was significantly higher in the group of patients with endoscopic hernia repair than in the group of patients who received a Shouldice repair. No significant differences were observed after the first postoperative day. A comparison between the TEP group and the patients who received conventional surgery under local anesthesia showed that the TEP approach was also associated with a higher postoperative neopterin level. Within the first 3 days after surgical intervention, bilateral endoscopic hernia repair induced no significantly higher inflammatory response than the surgical treatment of unilateral conditions. The anesthetic procedure that was used in the Shouldice operation had no significant effect on inflammatory response. Unlike other types of endoscopic surgery, the repair of groin hernias using an endoscopic technique cannot be regarded as a minimally invasive procedure that is less traumatic than conventional approaches. Instead, the conventional Shouldice procedure appears to cause the lowest inflammatory response and to be the least traumatic approach to hernia repair, especially when it is performed under local anesthesia.

Short-Term Audiological Results of Diode Laser in Comparison with Manual Perforation in Stapes Surgery

PubMed Central

Hamerschmidt, Rogerio; Saab, Stephanie Sbizera; Carvalho, Bettina; Carmo, Carolina do

2018-01-01

Introduction  Diode laser is a new alternative in stapes surgery for otosclerosis. The present study is the first to compare the short-term results of the surgery performed using diode laser to those obtained through the conventional fenestration technique. Objective  To use audiometry to establish a comparative analysis between the functional results obtained through surgery for otosclerosis using diode laser and the conventional technique. Method  Audiometric evaluation of 12 patients submitted to stapes surgery for otosclerosis, using diode laser or conventional fenestration by needle and drills, between 2014 and 2015. Each group was composed of 6 patients. Pre and post-operative measures were compared for three months in both groups. The speech recognition threshold, the air and bone conduction threshold, as well as the gap between them at 500 Hz, 1 KHz, 2 KHz and 4 KHz were measured. Results  Significant difference in bone conduction and SRT was observed when compared post- and preoperative results in the diode group. However diode and conventional technique groups presented significant differences in air conduction and air-bone gap, suggesting that both can provide functional improvement. Conclusion  Laser stapedotomy is a safe technique with good results. Both laser surgery and the conventional technique have improved the hearing of patients with a discreet advantage for the diode laser. Further prospective and randomized clinical trials are required to disclose all possible benefits of the stapes surgery using diode laser. PMID:29619098

Short-Term Audiological Results of Diode Laser in Comparison with Manual Perforation in Stapes Surgery.

PubMed

Hamerschmidt, Rogerio; Saab, Stephanie Sbizera; Carvalho, Bettina; Carmo, Carolina do

2018-04-01

Introduction  Diode laser is a new alternative in stapes surgery for otosclerosis. The present study is the first to compare the short-term results of the surgery performed using diode laser to those obtained through the conventional fenestration technique. Objective  To use audiometry to establish a comparative analysis between the functional results obtained through surgery for otosclerosis using diode laser and the conventional technique. Method  Audiometric evaluation of 12 patients submitted to stapes surgery for otosclerosis, using diode laser or conventional fenestration by needle and drills, between 2014 and 2015. Each group was composed of 6 patients. Pre and post-operative measures were compared for three months in both groups. The speech recognition threshold, the air and bone conduction threshold, as well as the gap between them at 500 Hz, 1 KHz, 2 KHz and 4 KHz were measured. Results  Significant difference in bone conduction and SRT was observed when compared post- and preoperative results in the diode group. However diode and conventional technique groups presented significant differences in air conduction and air-bone gap, suggesting that both can provide functional improvement. Conclusion  Laser stapedotomy is a safe technique with good results. Both laser surgery and the conventional technique have improved the hearing of patients with a discreet advantage for the diode laser. Further prospective and randomized clinical trials are required to disclose all possible benefits of the stapes surgery using diode laser.

Environmentally-assisted technique for transferring devices onto non-conventional substrates

DOEpatents

Lee, Chi-Hwan; Kim, Dong Rip; Zheng, Xiaolin

2014-08-26

A device fabrication method includes: (1) providing a growth substrate including a base and an oxide layer disposed over the base; (2) forming a metal layer over the oxide layer; (3) forming a stack of device layers over the metal layer; (4) performing interfacial debonding of the metal layer to separate the stack of device layers and the metal layer from the growth substrate; and (5) affixing the stack of device layers to a target substrate.

Field ion spectrometry: a new technology for cocaine and heroin detection

NASA Astrophysics Data System (ADS)

Carnahan, Byron L.; Day, Stephen; Kouznetsov, Viktor; Tarassov, Alexandre

1997-02-01

Field ion spectrometry, also known as transverse field compensation ion mobility spectrometry, is a new technique for trace gas analysis that can be applied to the detection of cocaine and heroin. Its principle is based on filtering ion species according to the functional dependence of their mobilities with electric field strength. Field ion spectrometry eliminates the gating electrodes needed in conventional IMS to pulse ions into the spectrometer; instead, ions are injected in to the spectrometer and reach the detector continuously, resulting in improved sensitivity. The technique enables analyses that are difficult with conventional constant field strength ion mobility spectrometers. We have shown that a filed ion spectrometer can selectively detect the vapors from cocaine and heroin emitted from both their base and hydrochloride forms. The estimated volumetric limits of detection are in the low pptv range, based on testing with standardized drug vapor generation systems. The spectrometer can detect cocaine base in the vapor phase, at concentrations well below its estimated 100 pptv vapor pressure equivalent at 20 degrees C. This paper describes the underlying principles of field ion spectrometry in relation to narcotic drug detection, and recent results obtained for cocaine and heroin. The work has been sponsored in part by the United States Advanced Research Projects Agency under contract DAAB10-95C-0004, for the DOD Counterdrug Technology Development Program.

Lesion Detection in CT Images Using Deep Learning Semantic Segmentation Technique

NASA Astrophysics Data System (ADS)

Kalinovsky, A.; Liauchuk, V.; Tarasau, A.

2017-05-01

In this paper, the problem of automatic detection of tuberculosis lesion on 3D lung CT images is considered as a benchmark for testing out algorithms based on a modern concept of Deep Learning. For training and testing of the algorithms a domestic dataset of 338 3D CT scans of tuberculosis patients with manually labelled lesions was used. The algorithms which are based on using Deep Convolutional Networks were implemented and applied in three different ways including slice-wise lesion detection in 2D images using semantic segmentation, slice-wise lesion detection in 2D images using sliding window technique as well as straightforward detection of lesions via semantic segmentation in whole 3D CT scans. The algorithms demonstrate superior performance compared to algorithms based on conventional image analysis methods.

Evaluation of gravimetric techniques to estimate the microvascular filtration coefficient

PubMed Central

Dongaonkar, R. M.; Laine, G. A.; Stewart, R. H.

2011-01-01

Microvascular permeability to water is characterized by the microvascular filtration coefficient (Kf). Conventional gravimetric techniques to estimate Kf rely on data obtained from either transient or steady-state increases in organ weight in response to increases in microvascular pressure. Both techniques result in considerably different estimates and neither account for interstitial fluid storage and lymphatic return. We therefore developed a theoretical framework to evaluate Kf estimation techniques by 1) comparing conventional techniques to a novel technique that includes effects of interstitial fluid storage and lymphatic return, 2) evaluating the ability of conventional techniques to reproduce Kf from simulated gravimetric data generated by a realistic interstitial fluid balance model, 3) analyzing new data collected from rat intestine, and 4) analyzing previously reported data. These approaches revealed that the steady-state gravimetric technique yields estimates that are not directly related to Kf and are in some cases directly proportional to interstitial compliance. However, the transient gravimetric technique yields accurate estimates in some organs, because the typical experimental duration minimizes the effects of interstitial fluid storage and lymphatic return. Furthermore, our analytical framework reveals that the supposed requirement of tying off all draining lymphatic vessels for the transient technique is unnecessary. Finally, our numerical simulations indicate that our comprehensive technique accurately reproduces the value of Kf in all organs, is not confounded by interstitial storage and lymphatic return, and provides corroboration of the estimate from the transient technique. PMID:21346245

Effect of mechanical alloying synthesis process on the dielectric properties of (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} piezoceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghazanfari, Mohammad Reza, E-mail: Ghazanfari.mr@gmail.com; Amini, Rasool; Shams, Seyyedeh Fatemeh

Highlights: • MA samples show higher dielectric permittivity and Curie temperature. • In MA samples, dielectric loss is almost 27% less than conventional ones. • In MA samples, sintering time and temperature are lower than conventional ones. • In MA samples, particle morphology is more homogeneous conventional ones. • In MA samples, crystallite size is smaller conventional ones. - Abstract: In present work, in order to study the effects of synthesis techniques on dielectric properties, the BNBT lead-free piezoceramics with (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} stoichiometry (called as BNBT6) were synthesized by mechanical alloying (MA) and conventional mixed oxidesmore » methods. The structural, microstructural, and dielectric properties were carried out by X-ray diffractometer (XRD), scanning electron microscope (SEM), and impedance analyzer LCR meter, respectively. Based on results, the density of MA samples is considerably higher than conventional samples owning to smaller particles size and more uniformity of particle shape of MA samples. Moreover, the dielectric properties of MA samples are comparatively improved in which the dielectric loss of these samples is almost 27% less than conventional ones. Furthermore, MA samples exhibit obviously higher dielectric permittivity and Curie temperature compared to the conventional samples.« less

A hot-cracking mitigation technique for welding high-strength aluminum alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Y.P.; Dong, P.; Zhang, J.

2000-01-01

A hot-cracking mitigation technique for gas tungsten arc welding (GTAW) of high-strength aluminum alloy 2024 is presented. The proposed welding technique incorporates a trailing heat sink (an intense cooling source) with respect to the welding torch. The development of the mitigation technique was based on both detailed welding process simulation using advanced finite element techniques and systematic laboratory experiments. The finite element methods were used to investigate the detailed thermomechanical behavior of the weld metal that undergoes the brittle temperature range (BTR) during welding. As expected, a tensile deformation zone within the material BTR region was identified behind the weldmore » pool under conventional GTA welding process conventional GTA welding process conditions for the aluminum alloy studied. To mitigate hot cracking, the tensile zone behind the weld pool must be eliminated or reduce to a satisfactory level if the weld metal hot ductility cannot be further improved. With detailed computational modeling, it was found that by the introduction of a trailing heat sink at some distance behind the welding arc, the tensile strain rate with respect to temperature in the zone encompassing the BTR region can be significantly reduced. A series of parametric studies were also conducted to derive optimal process parameters for the trailing heat sink. The experimental results confirmed the effectiveness of the trailing heat sink technique. With a proper implementation of the trailing heat sink method, hot cracking can be completely eliminated in welding aluminum alloy 2024 (AA 2024).« less

Improving mathematical problem solving ability through problem-based learning and authentic assessment for the students of Bali State Polytechnic

NASA Astrophysics Data System (ADS)

Darma, I. K.

2018-01-01

This research is aimed at determining: 1) the differences of mathematical problem solving ability between the students facilitated with problem-based learning model and conventional learning model, 2) the differences of mathematical problem solving ability between the students facilitated with authentic and conventional assessment model, and 3) interaction effect between learning and assessment model on mathematical problem solving. The research was conducted in Bali State Polytechnic, using the 2x2 experiment factorial design. The samples of this research were 110 students. The data were collected using a theoretically and empirically-validated test. Instruments were validated by using Aiken’s approach of technique content validity and item analysis, and then analyzed using anova stylistic. The result of the analysis shows that the students facilitated with problem-based learning and authentic assessment models get the highest score average compared to the other students, both in the concept understanding and mathematical problem solving. The result of hypothesis test shows that, significantly: 1) there is difference of mathematical problem solving ability between the students facilitated with problem-based learning model and conventional learning model, 2) there is difference of mathematical problem solving ability between the students facilitated with authentic assessment model and conventional assessment model, and 3) there is interaction effect between learning model and assessment model on mathematical problem solving. In order to improve the effectiveness of mathematics learning, collaboration between problem-based learning model and authentic assessment model can be considered as one of learning models in class.

Analyser-based mammography using single-image reconstruction.

PubMed

Briedis, Dahliyani; Siu, Karen K W; Paganin, David M; Pavlov, Konstantin M; Lewis, Rob A

2005-08-07

We implement an algorithm that is able to decode a single analyser-based x-ray phase-contrast image of a sample, converting it into an equivalent conventional absorption-contrast radiograph. The algorithm assumes the projection approximation for x-ray propagation in a single-material object embedded in a substrate of approximately uniform thickness. Unlike the phase-contrast images, which have both directional bias and a bias towards edges present in the sample, the reconstructed images are directly interpretable in terms of the projected absorption coefficient of the sample. The technique was applied to a Leeds TOR[MAM] phantom, which is designed to test mammogram quality by the inclusion of simulated microcalcifications, filaments and circular discs. This phantom was imaged at varying doses using three modalities: analyser-based synchrotron phase-contrast images converted to equivalent absorption radiographs using our algorithm, slot-scanned synchrotron imaging and imaging using a conventional mammography unit. Features in the resulting images were then assigned a quality score by volunteers. The single-image reconstruction method achieved higher scores at equivalent and lower doses than the conventional mammography images, but no improvement of visualization of the simulated microcalcifications, and some degradation in image quality at reduced doses for filament features.

Radiosurgical fistulotomy; an alternative to conventional procedure in fistula in ano.

PubMed

Gupta, Pravin J

2003-01-01

Most surgeons continue to prefer the classic lay open technique [fistulotomy] as the gold standard of treatment in anal fistula. In this randomized study, a comparison is made between conventional fistulotomy and fistulotomy performed by a radio frequency device. One hundred patients of low anal fistula posted for fistulotomy were randomized prospectively to either a conventional or radio frequency technique. Parameters measured included time taken for the procedure, amount of blood loss, postoperative pain, return to work, and recurrence rate. The patient demographic was comparable in 2 groups. The radio frequency fistulotomy was quicker as compared to a conventional one [22 versus 37 minutes, p = 0.001], amount of bleeding was significantly less [47 ml versus 134 ml, p = 0.002], and hospital stay was less when patient was operated by radio frequency method [37 hours versus 56 hours in conventional method, p = 0.001]. The postoperative pain in the first 24 hours was more in conventional group [2 to 5 versus 0 to 3 on visual analogue scale]. The patients from radio frequency group resumed their duties early with a reduced healing period of the wounds [47 versus 64 days, p = 0.01]. The recurrence or failure rates were comparable in the radio frequency and conventional groups [2% versus 6%]. Fistulotomy procedure using a radio frequency technique has significant advantages over a conventional procedure with regard to operation time, blood loss, return to normal activity, and healing time of the wound.

Viability PCR, a Culture-Independent Method for Rapid and Selective Quantification of Viable Legionella pneumophila Cells in Environmental Water Samples▿

PubMed Central

Delgado-Viscogliosi, Pilar; Solignac, Lydie; Delattre, Jean-Marie

2009-01-01

PCR-based methods have been developed to rapidly screen for Legionella pneumophila in water as an alternative to time-consuming culture techniques. However, these methods fail to discriminate between live and dead bacteria. Here, we report a viability assay (viability PCR [v-PCR]) for L. pneumophila that combines ethidium monoazide bromide with quantitative real-time PCR (qPCR). The ability of v-PCR to differentiate viable from nonviable L. pneumophila cells was confirmed with permeabilizing agents, toluene, or isopropanol. v-PCR suppressed more than 99.9% of the L. pneumophila PCR signal in nonviable cultures and was able to discriminate viable cells in mixed samples. A wide range of physiological states, from culturable to dead cells, was observed with 64 domestic hot-water samples after simultaneous quantification of L. pneumophila cells by v-PCR, conventional qPCR, and culture methods. v-PCR counts were equal to or higher than those obtained by culture and lower than or equal to conventional qPCR counts. v-PCR was used to successfully monitor in vitro the disinfection efficacy of heating to 70°C and glutaraldehyde and chlorine curative treatments. The v-PCR method appears to be a promising and rapid technique for enumerating L. pneumophila bacteria in water and, in comparison with conventional qPCR techniques used to monitor Legionella, has the advantage of selectively amplifying only viable cells. PMID:19363080

Fusion and Gaussian mixture based classifiers for SONAR data

NASA Astrophysics Data System (ADS)

Kotari, Vikas; Chang, KC

2011-06-01

Underwater mines are inexpensive and highly effective weapons. They are difficult to detect and classify. Hence detection and classification of underwater mines is essential for the safety of naval vessels. This necessitates a formulation of highly efficient classifiers and detection techniques. Current techniques primarily focus on signals from one source. Data fusion is known to increase the accuracy of detection and classification. In this paper, we formulated a fusion-based classifier and a Gaussian mixture model (GMM) based classifier for classification of underwater mines. The emphasis has been on sound navigation and ranging (SONAR) signals due to their extensive use in current naval operations. The classifiers have been tested on real SONAR data obtained from University of California Irvine (UCI) repository. The performance of both GMM based classifier and fusion based classifier clearly demonstrate their superior classification accuracy over conventional single source cases and validate our approach.

Single Wall Carbon Nanotube-Based Structural Health Sensing Materials

NASA Technical Reports Server (NTRS)

Watkins, A. Neal; Ingram, JoAnne L.; Jordan, Jeffrey D.; Wincheski, Russell A.; Smits, Jan M.; Williams, Phillip A.

2004-01-01

Single wall carbon nanotube (SWCNT)-based materials represent the future aerospace vehicle construction material of choice based primarily on predicted strength-to-weight advantages and inherent multifunctionality. The multifunctionality of SWCNTs arises from the ability of the nanotubes to be either metallic or semi-conducting based on their chirality. Furthermore, simply changing the environment around a SWCNT can change its conducting behavior. This phenomenon is being exploited to create sensors capable of measuring several parameters related to vehicle structural health (i.e. strain, pressure, temperature, etc.) The structural health monitor is constructed using conventional electron-beam lithographic and photolithographic techniques to place specific electrode patterns on a surface. SWCNTs are then deposited between the electrodes using a dielectrophoretic alignment technique. Prototypes have been constructed on both silicon and polyimide substrates, demonstrating that surface-mountable and multifunctional devices based on SWCNTs can be realized.

Aeroservoelastic stabilization technique refinement for hypersonic flight vehicles

NASA Technical Reports Server (NTRS)

Cheng, Peter Y.; Chan, Samuel Y.; Myers, Thomas T.; Klyde, David H.; Mcruer, Duane T.

1992-01-01

Conventional gain-stabilization techniques introduce low frequency effective time delays which can be troublesome from the viewpoint of SSTOV vehicles' flying qualities. These time delays can be alleviated through a blending of gain-stabilization and phase-stabilization techniques; the resulting hybrid phase stabilization (HPS) for the low-frequency structural modes has been noted to have greater residual response than a conventional gain-stabilizer design. HPS design procedures are presently refined, and residual response metrics are developed.

High prevalence of Strongyloides stercoralis in school-aged children in a rural highland of north-western Ethiopia: the role of intensive diagnostic work-up.

PubMed

Amor, Aranzazu; Rodriguez, Esperanza; Saugar, José M; Arroyo, Ana; López-Quintana, Beatriz; Abera, Bayeh; Yimer, Mulat; Yizengaw, Endalew; Zewdie, Derejew; Ayehubizu, Zimman; Hailu, Tadesse; Mulu, Wondemagegn; Echazú, Adriana; Krolewieki, Alejandro J; Aparicio, Pilar; Herrador, Zaida; Anegagrie, Melaku; Benito, Agustín

2016-12-01

Soil-transmitted helminthiases (hookworms, Ascaris lumbricoides and Trichuris trichiura) are extremely prevalent in school-aged children living in poor sanitary conditions. Recent epidemiological data suggest that Strongyloides stercoralis is highly unreported. However, accurate data are essential for conducting interventions aimed at introducing control and elimination programmes. We conducted a cross-sectional survey of 396 randomly selected school-aged children in Amhara region in rural area in north-western Ethiopia, to assess the prevalence of S. stercoralis and other intestinal helminths. We examined stools using three techniques: conventional stool concentration; and two S. stercoralis-specific methods, i.e. the Baermann technique and polymerase chain reaction. The diagnostic accuracy of these three methods was then compared. There was an overall prevalence of helminths of 77.5%, with distribution differing according to school setting. Soil-transmitted helminths were recorded in 69.2%. Prevalence of S. stercoralis and hookworm infection was 20.7 and 54.5%, respectively, and co-infection was detected in 16.3% of cases. Schistosoma mansoni had a prevalence of 15.7%. Prevalence of S. stercoralis was shown 3.5% by the conventional method, 12.1% by the Baermann method, and 13.4% by PCR, which thus proved to be the most sensitive. Our results suggest that S. stercoralis could be overlooked and neglected in Ethiopia, if studies of soil-transmitted helminths rely on conventional diagnostic techniques alone. A combination of molecular and stool microscopy techniques yields a significantly higher prevalence. In view of the fact that current control policies for triggering drug administration are based on parasite prevalence levels, a comprehensive diagnostic approach should instead be applied to ensure comprehensive control of helminth infections.

Relation between hardness and ultrasonic velocity on pipeline steel welded joints

NASA Astrophysics Data System (ADS)

Carreón, H.; Barrera, G.; Natividad, C.; Salazar, M.; Contreras, A.

2016-04-01

In general, the ultrasonic techniques have been used to determine the mechanical properties of materials based on their relationship with metallurgical characteristics. In this research work, the relationship between ultrasonic wave velocity, hardness and the microstructure of steel pipeline welded joints is investigated. Measurements of ultrasonic wave velocity were made as a function of the location across the weld. Hardness measurements were performed in an attempt to correlate with ultrasonic response. In addition, the coarse and dendritic grain structure of the weld material is extreme and unpredictably anisotropic. Thus, due to the acoustic anisotropy of the crystal, weld material of studied joints is anisotropic too. Such structure is no longer direction-independent to the ultrasonic wave propagation; therefore, the ultrasonic beam deflects and redirects and the wave front becomes distorted. Thus, the use of conventional ultrasonic testing techniques using fixed beam angles is very limited and the application of conventional ultrasonic phased array techniques becomes desirable. This technique is proposed to assist pipeline operators in estimating the hardness through ultrasonic measures to evaluate the susceptibility to stress sulphide cracking and hydrogen-induced cracking due to hard spots in steel pipeline welded joints in service. Sound wave velocity and hardness measurements have been carried out on a steel welded joint. For each section of the welding, weld bead, fusion zone, heat affected zone and base metal were found to correspond particular values of the ultrasound velocity. These results were correlated with electron microscopy observations of the microstructure and sectorial scan view of welded joints by ultrasonic phased array.

Design and application of discrete wavelet packet transform based multiresolution controller for liquid level system.

PubMed

Paul, Rimi; Sengupta, Anindita

2017-11-01

A new controller based on discrete wavelet packet transform (DWPT) for liquid level system (LLS) has been presented here. This controller generates control signal using node coefficients of the error signal which interprets many implicit phenomena such as process dynamics, measurement noise and effect of external disturbances. Through simulation results on LLS problem, this controller is shown to perform faster than both the discrete wavelet transform based controller and conventional proportional integral controller. Also, it is more efficient in terms of its ability to provide better noise rejection. To overcome the wind up phenomenon by considering the saturation due to presence of actuator, anti-wind up technique is applied to the conventional PI controller and compared to the wavelet packet transform based controller. In this case also, packet controller is found better than the other ones. This similar work has been extended for analogous first order RC plant as well as second order plant also. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Fluence-based and microdosimetric event-based methods for radiation protection in space

NASA Technical Reports Server (NTRS)

Curtis, Stanley B.; Meinhold, C. B. (Principal Investigator)

2002-01-01

The National Council on Radiation Protection and Measurements (NCRP) has recently published a report (Report #137) that discusses various aspects of the concepts used in radiation protection and the difficulties in measuring the radiation environment in spacecraft for the estimation of radiation risk to space travelers. Two novel dosimetric methodologies, fluence-based and microdosimetric event-based methods, are discussed and evaluated, along with the more conventional quality factor/LET method. It was concluded that for the present, any reason to switch to a new methodology is not compelling. It is suggested that because of certain drawbacks in the presently-used conventional method, these alternative methodologies should be kept in mind. As new data become available and dosimetric techniques become more refined, the question should be revisited and that in the future, significant improvement might be realized. In addition, such concepts as equivalent dose and organ dose equivalent are discussed and various problems regarding the measurement/estimation of these quantities are presented.

Comparison of dual and single exposure techniques in dual-energy chest radiography.

PubMed

Ho, J T; Kruger, R A; Sorenson, J A

1989-01-01

Conventional chest radiography is the most effective tool for lung cancer detection and diagnosis; nevertheless, a high percentage of lung cancer tumors are missed because of the overlap of lung nodule image contrast with bone image contrast in a chest radiograph. Two different energy subtraction strategies, dual exposure and single exposure techniques, were studied for decomposing a radiograph into bone-free and soft tissue-free images to address this problem. For comparing the efficiency of these two techniques in lung nodule detection, the performances of the techniques were evaluated on the basis of residual tissue contrast, energy separation, and signal-to-noise ratio. The evaluation was based on both computer simulation and experimental verification. The dual exposure technique was found to be better than the single exposure technique because of its higher signal-to-noise ratio and greater residual tissue contrast. However, x-ray tube loading and patient motion are problems.

Geophysical monitoring technology for CO2 sequestration

NASA Astrophysics Data System (ADS)

Ma, Jin-Feng; Li, Lin; Wang, Hao-Fan; Tan, Ming-You; Cui, Shi-Ling; Zhang, Yun-Yin; Qu, Zhi-Peng; Jia, Ling-Yun; Zhang, Shu-Hai

2016-06-01

Geophysical techniques play key roles in the measuring, monitoring, and verifying the safety of CO2 sequestration and in identifying the efficiency of CO2-enhanced oil recovery. Although geophysical monitoring techniques for CO2 sequestration have grown out of conventional oil and gas geophysical exploration techniques, it takes a long time to conduct geophysical monitoring, and there are many barriers and challenges. In this paper, with the initial objective of performing CO2 sequestration, we studied the geophysical tasks associated with evaluating geological storage sites and monitoring CO2 sequestration. Based on our review of the scope of geophysical monitoring techniques and our experience in domestic and international carbon capture and sequestration projects, we analyzed the inherent difficulties and our experiences in geophysical monitoring techniques, especially, with respect to 4D seismic acquisition, processing, and interpretation.

A novel fiber-free technique for brain activity imaging in multiple freely behaving mice

NASA Astrophysics Data System (ADS)

Inagaki, Shigenori; Agetsuma, Masakazu; Nagai, Takeharu

2018-02-01

Brain functions and related psychiatric disorders have been investigated by recording electrophysiological field potential. When recording it, a conventional method requires fiber-based apparatus connected to the brain, which however hampers the simultaneous measurement in multiple animals (e.g. by a tangle of fibers). Here, we propose a fiber-free recording technique in conjunction with a ratiometric bioluminescent voltage indicator. Our method allows investigation of electrophysiological filed potential dynamics in multiple freely behaving animals simultaneously over a long time period. Therefore, this fiber-free technique opens up the way to investigate a new mechanism of brain function that governs social behaviors and animal-to-animal interaction.

Electrospinning bioactive supramolecular polymers from water.

PubMed

Tayi, Alok S; Pashuck, E Thomas; Newcomb, Christina J; McClendon, Mark T; Stupp, Samuel I

2014-04-14

Electrospinning is a high-throughput, low-cost technique for manufacturing long fibers from solution. Conventionally, this technique is used with covalent polymers with large molecular weights. We report here the electrospinning of functional peptide-based supramolecular polymers from water at very low concentrations (<4 wt %). Molecules with low molecular weights (<1 kDa) could be electrospun because they self-assembled into one-dimensional supramolecular polymers upon solvation and the critical parameters of viscosity, solution conductivity, and surface tension were optimized for this technique. The supramolecular structure of the electrospun fibers could ensure that certain residues, like bioepitopes, are displayed on the surface even after processing. This system provides an opportunity to electrospin bioactive supramolecular materials from water for biomedical applications.

Compton imaging tomography technique for NDE of large nonuniform structures

NASA Astrophysics Data System (ADS)

Grubsky, Victor; Romanov, Volodymyr; Patton, Ned; Jannson, Tomasz

2011-09-01

In this paper we describe a new nondestructive evaluation (NDE) technique called Compton Imaging Tomography (CIT) for reconstructing the complete three-dimensional internal structure of an object, based on the registration of multiple two-dimensional Compton-scattered x-ray images of the object. CIT provides high resolution and sensitivity with virtually any material, including lightweight structures and organics, which normally pose problems in conventional x-ray computed tomography because of low contrast. The CIT technique requires only one-sided access to the object, has no limitation on the object's size, and can be applied to high-resolution real-time in situ NDE of large aircraft/spacecraft structures and components. Theoretical and experimental results will be presented.

Enhanced subcarrier-index modulation-based asymmetrically clipped optical OFDM using even subcarriers

NASA Astrophysics Data System (ADS)

Guan, Rui; Xu, Wei; Yang, Zhaohui; Huang, Nuo; Wang, Jin-Yuan; Chen, Ming

2017-11-01

In this paper, we propose a subcarrier-index modulation-based asymmetrically clipped optical orthogonal frequency division multiplexing (SACO-OFDM) scheme for optical wireless communication (OWC) systems, which benefits from the subcarrier-index modulation (SIM) and asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) techniques. SACO-OFDM conveys additional information via the subcarrier indexing, and the error rate of the bit transmitted by the subcarrier indexing is much lower than that of the conventional M-ary modulation scheme. On the other hand, as the signal constellation in M-ary modulation is relieved, SACO-OFDM has simple transceiver structure and low detection complexity. Moreover, considering the spectral, an enhanced SACO-OFDM (ESACO-OFDM) using even subcarriers is proposed. In this technique, the odd subcarriers are activated for SACO-OFDM, and the imaginary part of even subcarriers are activated for pulse-amplitude-modulated discrete multitone (PAM-DMT). Clearly, ESACO-OFDM achieves better spectral efficiency than the conventional optical OFDM, since all subcarriers are used for data transmission. Simulation results verify the significant bit error rate (BER) and peak-to-average power ratio (PAPR) improvement by the proposed ESACO-OFDM, especially for the medium-to-high signal-to-noise ratio (SNR) regime.

Formation mechanisms of boron oxide films fabricated by large-area electron beam-induced deposition of trimethyl borate [Formation Mechanisms of Boron Oxide Fillms Fabricated by Large Area Electron Beam-Induced Deposition of Trimethyl Borate

DOE PAGES

Martin, Aiden A.; Depond, Philip J.

2018-04-24

Boron-containing materials are increasingly drawing interest for the use in electronics, optics, laser targets, neutron absorbers, and high-temperature and chemically resistant ceramics. In this article, the first investigation into the deposition of boron-based material via electron beam-induced deposition (EBID) is reported. Thin films were deposited using a novel, large-area EBID system that is shown to deposit material at rates comparable to conventional techniques such as laser-induced chemical vapor deposition. The deposition rate and stoichiometry of boron oxide fabricated by EBID using trimethyl borate (TMB) as precursor is found to be critically dependent on the substrate temperature. By comparing the depositionmore » mechanisms of TMB to the conventional, alkoxide-based precursor tetraethyl orthosilicate it is revealed that ligand chemistry does not precisely predict the pathways leading to deposition of material via EBID. Lastly, the results demonstrate the first boron-containing material deposited by the EBID process and the potential for EBID as a scalable fabrication technique that could have a transformative effect on the athermal deposition of materials.« less

Formation mechanisms of boron oxide films fabricated by large-area electron beam-induced deposition of trimethyl borate [Formation Mechanisms of Boron Oxide Fillms Fabricated by Large Area Electron Beam-Induced Deposition of Trimethyl Borate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Aiden A.; Depond, Philip J.

Boron-containing materials are increasingly drawing interest for the use in electronics, optics, laser targets, neutron absorbers, and high-temperature and chemically resistant ceramics. In this article, the first investigation into the deposition of boron-based material via electron beam-induced deposition (EBID) is reported. Thin films were deposited using a novel, large-area EBID system that is shown to deposit material at rates comparable to conventional techniques such as laser-induced chemical vapor deposition. The deposition rate and stoichiometry of boron oxide fabricated by EBID using trimethyl borate (TMB) as precursor is found to be critically dependent on the substrate temperature. By comparing the depositionmore » mechanisms of TMB to the conventional, alkoxide-based precursor tetraethyl orthosilicate it is revealed that ligand chemistry does not precisely predict the pathways leading to deposition of material via EBID. Lastly, the results demonstrate the first boron-containing material deposited by the EBID process and the potential for EBID as a scalable fabrication technique that could have a transformative effect on the athermal deposition of materials.« less

Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes.

PubMed

Zhou, Du; Yuan, Xi; Gao, Haoxiang; Wang, Ailing; Liu, Jun; El Fakir, Omer; Politis, Denis J; Wang, Liliang; Lin, Jianguo

2016-12-13

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the efficiency and lowering the development time of such processes, whilst reducing costs involved in trial-and-error prototyping. Recent focus on the substitution of steel components with aluminum alloy alternatives in the automotive and aerospace sectors has increased the need to simulate the forming behavior of such alloys for ever more complex component geometries. However these alloys, and in particular their high strength variants, exhibit limited formability at room temperature, and high temperature manufacturing technologies have been developed to form them. Consequently, advanced constitutive models are required to reflect the associated temperature and strain rate effects. Simulating such behavior is computationally very expensive using conventional FE simulation techniques. This paper presents a novel Knowledge Based Cloud FE (KBC-FE) simulation technique that combines advanced material and friction models with conventional FE simulations in an efficient manner thus enhancing the capability of commercial simulation software packages. The application of these methods is demonstrated through two example case studies, namely: the prediction of a material's forming limit under hot stamping conditions, and the tool life prediction under multi-cycle loading conditions.

Label-Free, Flow-Imaging Methods for Determination of Cell Concentration and Viability.

PubMed

Sediq, A S; Klem, R; Nejadnik, M R; Meij, P; Jiskoot, Wim

2018-05-30

To investigate the potential of two flow imaging microscopy (FIM) techniques (Micro-Flow Imaging (MFI) and FlowCAM) to determine total cell concentration and cell viability. B-lineage acute lymphoblastic leukemia (B-ALL) cells of 2 different donors were exposed to ambient conditions. Samples were taken at different days and measured with MFI, FlowCAM, hemocytometry and automated cell counting. Dead and live cells from a fresh B-ALL cell suspension were fractionated by flow cytometry in order to derive software filters based on morphological parameters of separate cell populations with MFI and FlowCAM. The filter sets were used to assess cell viability in the measured samples. All techniques gave fairly similar cell concentration values over the whole incubation period. MFI showed to be superior with respect to precision, whereas FlowCAM provided particle images with a higher resolution. Moreover, both FIM methods were able to provide similar results for cell viability as the conventional methods (hemocytometry and automated cell counting). FIM-based methods may be advantageous over conventional cell methods for determining total cell concentration and cell viability, as FIM measures much larger sample volumes, does not require labeling, is less laborious and provides images of individual cells.

Evolutionary Optimization of Centrifugal Nozzles for Organic Vapours

NASA Astrophysics Data System (ADS)

Persico, Giacomo

2017-03-01

This paper discusses the shape-optimization of non-conventional centrifugal turbine nozzles for Organic Rankine Cycle applications. The optimal aerodynamic design is supported by the use of a non-intrusive, gradient-free technique specifically developed for shape optimization of turbomachinery profiles. The method is constructed as a combination of a geometrical parametrization technique based on B-Splines, a high-fidelity and experimentally validated Computational Fluid Dynamic solver, and a surrogate-based evolutionary algorithm. The non-ideal gas behaviour featuring the flow of organic fluids in the cascades of interest is introduced via a look-up-table approach, which is rigorously applied throughout the whole optimization process. Two transonic centrifugal nozzles are considered, featuring very different loading and radial extension. The use of a systematic and automatic design method to such a non-conventional configuration highlights the character of centrifugal cascades; the blades require a specific and non-trivial definition of the shape, especially in the rear part, to avoid the onset of shock waves. It is shown that the optimization acts in similar way for the two cascades, identifying an optimal curvature of the blade that both provides a relevant increase of cascade performance and a reduction of downstream gradients.

Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes

PubMed Central

Zhou, Du; Yuan, Xi; Gao, Haoxiang; Wang, Ailing; Liu, Jun; El Fakir, Omer; Politis, Denis J.; Wang, Liliang; Lin, Jianguo

2016-01-01

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the efficiency and lowering the development time of such processes, whilst reducing costs involved in trial-and-error prototyping. Recent focus on the substitution of steel components with aluminum alloy alternatives in the automotive and aerospace sectors has increased the need to simulate the forming behavior of such alloys for ever more complex component geometries. However these alloys, and in particular their high strength variants, exhibit limited formability at room temperature, and high temperature manufacturing technologies have been developed to form them. Consequently, advanced constitutive models are required to reflect the associated temperature and strain rate effects. Simulating such behavior is computationally very expensive using conventional FE simulation techniques. This paper presents a novel Knowledge Based Cloud FE (KBC-FE) simulation technique that combines advanced material and friction models with conventional FE simulations in an efficient manner thus enhancing the capability of commercial simulation software packages. The application of these methods is demonstrated through two example case studies, namely: the prediction of a material's forming limit under hot stamping conditions, and the tool life prediction under multi-cycle loading conditions. PMID:28060298

Task-driven imaging in cone-beam computed tomography.

PubMed

Gang, G J; Stayman, J W; Ouadah, S; Ehtiati, T; Siewerdsen, J H

Conventional workflow in interventional imaging often ignores a wealth of prior information of the patient anatomy and the imaging task. This work introduces a task-driven imaging framework that utilizes such information to prospectively design acquisition and reconstruction techniques for cone-beam CT (CBCT) in a manner that maximizes task-based performance in subsequent imaging procedures. The framework is employed in jointly optimizing tube current modulation, orbital tilt, and reconstruction parameters in filtered backprojection reconstruction for interventional imaging. Theoretical predictors of noise and resolution relates acquisition and reconstruction parameters to task-based detectability. Given a patient-specific prior image and specification of the imaging task, an optimization algorithm prospectively identifies the combination of imaging parameters that maximizes task-based detectability. Initial investigations were performed for a variety of imaging tasks in an elliptical phantom and an anthropomorphic head phantom. Optimization of tube current modulation and view-dependent reconstruction kernel was shown to have greatest benefits for a directional task (e.g., identification of device or tissue orientation). The task-driven approach yielded techniques in which the dose and sharp kernels were concentrated in views contributing the most to the signal power associated with the imaging task. For example, detectability of a line pair detection task was improved by at least three fold compared to conventional approaches. For radially symmetric tasks, the task-driven strategy yielded results similar to a minimum variance strategy in the absence of kernel modulation. Optimization of the orbital tilt successfully avoided highly attenuating structures that can confound the imaging task by introducing noise correlations masquerading at spatial frequencies of interest. This work demonstrated the potential of a task-driven imaging framework to improve image quality and reduce dose beyond that achievable with conventional imaging approaches.

An adaptive technique to maximize lossless image data compression of satellite images

NASA Technical Reports Server (NTRS)

Stewart, Robert J.; Lure, Y. M. Fleming; Liou, C. S. Joe

1994-01-01

Data compression will pay an increasingly important role in the storage and transmission of image data within NASA science programs as the Earth Observing System comes into operation. It is important that the science data be preserved at the fidelity the instrument and the satellite communication systems were designed to produce. Lossless compression must therefore be applied, at least, to archive the processed instrument data. In this paper, we present an analysis of the performance of lossless compression techniques and develop an adaptive approach which applied image remapping, feature-based image segmentation to determine regions of similar entropy and high-order arithmetic coding to obtain significant improvements over the use of conventional compression techniques alone. Image remapping is used to transform the original image into a lower entropy state. Several techniques were tested on satellite images including differential pulse code modulation, bi-linear interpolation, and block-based linear predictive coding. The results of these experiments are discussed and trade-offs between computation requirements and entropy reductions are used to identify the optimum approach for a variety of satellite images. Further entropy reduction can be achieved by segmenting the image based on local entropy properties then applying a coding technique which maximizes compression for the region. Experimental results are presented showing the effect of different coding techniques for regions of different entropy. A rule-base is developed through which the technique giving the best compression is selected. The paper concludes that maximum compression can be achieved cost effectively and at acceptable performance rates with a combination of techniques which are selected based on image contextual information.

Discrete square root filtering - A survey of current techniques.

NASA Technical Reports Server (NTRS)

Kaminskii, P. G.; Bryson, A. E., Jr.; Schmidt, S. F.

1971-01-01

Current techniques in square root filtering are surveyed and related by applying a duality association. Four efficient square root implementations are suggested, and compared with three common conventional implementations in terms of computational complexity and precision. It is shown that the square root computational burden should not exceed the conventional by more than 50% in most practical problems. An examination of numerical conditioning predicts that the square root approach can yield twice the effective precision of the conventional filter in ill-conditioned problems. This prediction is verified in two examples.

Conventional and Piecewise Growth Modeling Techniques: Applications and Implications for Investigating Head Start Children's Early Literacy Learning

ERIC Educational Resources Information Center

Hindman, Annemarie H.; Cromley, Jennifer G.; Skibbe, Lori E.; Miller, Alison L.

2011-01-01

This article reviews the mechanics of conventional and piecewise growth models to demonstrate the unique affordances of each technique for examining the nature and predictors of children's early literacy learning during the transition from preschool through first grade. Using the nationally representative Family and Child Experiences Survey…

Clinical application of microsampling versus conventional sampling techniques in the quantitative bioanalysis of antibiotics: a systematic review.

PubMed

Guerra Valero, Yarmarly C; Wallis, Steven C; Lipman, Jeffrey; Stove, Christophe; Roberts, Jason A; Parker, Suzanne L

2018-03-01

Conventional sampling techniques for clinical pharmacokinetic studies often require the removal of large blood volumes from patients. This can result in a physiological or emotional burden, particularly for neonates or pediatric patients. Antibiotic pharmacokinetic studies are typically performed on healthy adults or general ward patients. These may not account for alterations to a patient's pathophysiology and can lead to suboptimal treatment. Microsampling offers an important opportunity for clinical pharmacokinetic studies in vulnerable patient populations, where smaller sample volumes can be collected. This systematic review provides a description of currently available microsampling techniques and an overview of studies reporting the quantitation and validation of antibiotics using microsampling. A comparison of microsampling to conventional sampling in clinical studies is included.

An in vitro comparison of photogrammetric and conventional complete-arch implant impression techniques.

PubMed

Bergin, Junping Ma; Rubenstein, Jeffrey E; Mancl, Lloyd; Brudvik, James S; Raigrodski, Ariel J

2013-10-01

Conventional impression techniques for recording the location and orientation of implant-supported, complete-arch prostheses are time consuming and prone to error. The direct optical recording of the location and orientation of implants, without the need for intermediate transfer steps, could reduce or eliminate those disadvantages. The objective of this study was to assess the feasibility of using a photogrammetric technique to record the location and orientation of multiple implants and to compare the results with those of a conventional complete-arch impression technique. A stone cast of an edentulous mandibular arch containing 5 implant analogs was fabricated to create a master model. The 3-dimensional (3D) spatial orientations of implant analogs on the master model were measured with a coordinate measuring machine (CMM) (control). Five definitive casts were made from the master model with a splinted impression technique. The positions of the implant analogs on the 5 casts were measured with a NobelProcera scanner (conventional method). Prototype optical targets were attached to the master model implant analogs, and 5 sets of images were recorded with a digital camera and a standardized image capture protocol. Dimensional data were imported into commercially available photogrammetry software (photogrammetric method). The precision and accuracy of the 2 methods were compared with a 2-sample t test (α=.05) and a 95% confidence interval. The location precision (standard error of measurement) for CMM was 3.9 µm (95% CI 2.7 to 7.1), for photogrammetry, 5.6 µm (95% CI 3.4 to 16.1), and for the conventional method, 17.2 µm (95% CI 10.3 to 49.4). The average measurement error was 26.2 µm (95% CI 15.9 to 36.6) for the conventional method and 28.8 µm (95% CI 24.8 to 32.9) for the photogrammetric method. The overall measurement accuracy was not significantly different when comparing the conventional to the photogrammetric method (mean difference = -2.6 µm, 95% CI -12.8 to 7.6). The precision of the photogrammetric method was similar to CMM, but lower for the conventional method as compared to CMM and the photogrammetric method. However, the overall measurement accuracy of the photogrammetric and conventional methods was similar. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Remote sensing techniques for prediction of watershed runoff

NASA Technical Reports Server (NTRS)

Blanchard, B. J.

1975-01-01

Hydrologic parameters of watersheds for use in mathematical models and as design criteria for flood detention structures are sometimes difficult to quantify using conventional measuring systems. The advent of remote sensing devices developed in the past decade offers the possibility that watershed characteristics such as vegetative cover, soils, soil moisture, etc., may be quantified rapidly and economically. Experiments with visible and near infrared data from the LANDSAT-1 multispectral scanner indicate a simple technique for calibration of runoff equation coefficients is feasible. The technique was tested on 10 watersheds in the Chickasha area and test results show more accurate runoff coefficients were obtained than with conventional methods. The technique worked equally as well using a dry fall scene. The runoff equation coefficients were then predicted for 22 subwatersheds with flood detention structures. Predicted values were again more accurate than coefficients produced by conventional methods.

New spatial diversity equalizer based on PLL

NASA Astrophysics Data System (ADS)

Rao, Wei

2011-10-01

A new Spatial Diversity Equalizer (SDE) based on phase-locked loop (PLL) is proposed to overcome the inter-symbol interference (ISI) and phase rotations simultaneously in the digital communication system. The proposed SDE consists of equal gain combining technique based on a famous blind equalization algorithm constant modulus algorithm (CMA) and a PLL. Compared with conventional SDE, the proposed SDE has not only faster convergence rate and lower residual error but also the ability to recover carrier phase rotation. The efficiency of the method is proved by computer simulation.

Exploration of oxide-based diluted magnetic semiconductors toward transparent spintronics

NASA Astrophysics Data System (ADS)

Fukumura, T.; Yamada, Y.; Toyosaki, H.; Hasegawa, T.; Koinuma, H.; Kawasaki, M.

2004-02-01

A review is given for the recent progress of research in the field of oxide-based diluted magnetic semiconductor (DMS), which was triggered by combinatorial discovery of transparent ferromagnet. The possible advantages of oxide semiconductor as a host of DMS are described in comparison with conventional compound semiconductors. Limits and problems for identifying novel ferromagnetic DMS are described in view of recent reports in this field. Several characterization techniques are proposed in order to eliminate unidentified ferromagnetism of oxide-based DMS unidentified ferromagnetic oxide (UFO). Perspectives and possible devices are also given.

Plant Ethylene Detection Using Laser-Based Photo-Acoustic Spectroscopy.

PubMed

Van de Poel, Bram; Van Der Straeten, Dominique

2017-01-01

Analytical detection of the plant hormone ethylene is an important prerequisite in physiological studies. Real-time and super sensitive detection of trace amounts of ethylene gas is possible using laser-based photo-acoustic spectroscopy. This Chapter will provide some background on the technique, compare it with conventional gas chromatography, and provide a detailed user-friendly hand-out on how to operate the machine and the software. In addition, this Chapter provides some tips and tricks for designing and performing physiological experiments suited for ethylene detection with laser-based photo-acoustic spectroscopy.

Diagnosis of toxoplasmosis and typing of Toxoplasma gondii.

PubMed

Liu, Quan; Wang, Ze-Dong; Huang, Si-Yang; Zhu, Xing-Quan

2015-05-28

Toxoplasmosis, caused by the obligate intracellular protozoan Toxoplasma gondii, is an important zoonosis with medical and veterinary importance worldwide. The disease is mainly contracted by ingesting undercooked or raw meat containing viable tissue cysts, or by ingesting food or water contaminated with oocysts. The diagnosis and genetic characterization of T. gondii infection is crucial for the surveillance, prevention and control of toxoplasmosis. Traditional approaches for the diagnosis of toxoplasmosis include etiological, immunological and imaging techniques. Diagnosis of toxoplasmosis has been improved by the emergence of molecular technologies to amplify parasite nucleic acids. Among these, polymerase chain reaction (PCR)-based molecular techniques have been useful for the genetic characterization of T. gondii. Serotyping methods based on polymorphic polypeptides have the potential to become the choice for typing T. gondii in humans and animals. In this review, we summarize conventional non-DNA-based diagnostic methods, and the DNA-based molecular techniques for the diagnosis and genetic characterization of T. gondii. These techniques have provided foundations for further development of more effective and accurate detection of T. gondii infection. These advances will contribute to an improved understanding of the epidemiology, prevention and control of toxoplasmosis.

A Profilometry-Based Dentifrice Abrasion Method for V8 Brushing Machines Part II: Comparison of RDA-PE and Radiotracer RDA Measures.

PubMed

Schneiderman, Eva; Colón, Ellen; White, Donald J; St John, Samuel

2015-01-01

The purpose of this study was to compare the abrasivity of commercial dentifrices by two techniques: the conventional gold standard radiotracer-based Radioactive Dentin Abrasivity (RDA) method; and a newly validated technique based on V8 brushing that included a profilometry-based evaluation of dentin wear. This profilometry-based method is referred to as RDA-Profilometry Equivalent, or RDA-PE. A total of 36 dentifrices were sourced from four global dentifrice markets (Asia Pacific [including China], Europe, Latin America, and North America) and tested blindly using both the standard radiotracer (RDA) method and the new profilometry method (RDA-PE), taking care to follow specific details related to specimen preparation and treatment. Commercial dentifrices tested exhibited a wide range of abrasivity, with virtually all falling well under the industry accepted upper limit of 250; that is, 2.5 times the level of abrasion measured using an ISO 11609 abrasivity reference calcium pyrophosphate as the reference control. RDA and RDA-PE comparisons were linear across the entire range of abrasivity (r2 = 0.7102) and both measures exhibited similar reproducibility with replicate assessments. RDA-PE assessments were not just linearly correlated, but were also proportional to conventional RDA measures. The linearity and proportionality of the results of the current study support that both methods (RDA or RDA-PE) provide similar results and justify a rationale for making the upper abrasivity limit of 250 apply to both RDA and RDA-PE.

Low-Temperature Growth and Doping of Mercury-Based II-Vi Multiple Quantum Well Structures by Molecular Beam Epitaxy

NASA Astrophysics Data System (ADS)

Lansari, Yamina

The growth of Hg-based single layers and multiple quantum well structures by conventional molecular beam epitaxy (MBE) and photoassisted MBE was studied. The use of photoassisted MBE, an epitaxial growth technique developed at NCSU, has resulted in a substantial reduction of the film growth temperature. Indeed, substrate temperatures 50 to 100^circC lower than those customarily used by others for conventional MBE growth of Hg-based layers were successfully employed. Photoassisted MBE allowed the preparation of excellent structural quality HgTe layers (FWHM for the (400) diffraction peak ~ 40 arcsec), HgCdTe layers (FWHM for the (400) diffraction peak ~ 14 arcsec), and HgTeCdTe superlattices (FWHM for the (400) diffraction peak ~ 28 arcsec). In addition, n-type and p-type modulation-doping of Hg-based multilayers was accomplished by photoassisted MBE. This technique has been shown to have a significant effect on the growth process kinetics as well as on the desorption rates of the film species, thereby affecting dopant incorporation mechanisms and allowing for the successful substitutional doping of the multilayer structures. Finally, surface morphology studies were completed using scanning electron microscopy (SEM) and Nomarsky optical microscopy to study the effects of substrate surface preparation, growth initiation, and growth parameters on the density of pyramidal hillocks, a common growth defect plaguing the Hg-based layers grown in the (100) direction. Conditions which minimize the hillock density for (100) film growth have been determined.

A study of reduced chromium content in a nickel-base superalloy via element substitution and rapid solidification processing. Ph.D. ThesisFinal Report

NASA Technical Reports Server (NTRS)

Powers, William O.

1987-01-01

A study of reduced chromium content in a nickel base superalloy via element substitution and rapid solidification processing was performed. The two elements used as partial substitutes for chromium were Si and Zr. The microstructure of conventionally solidified materials was characterized using microscopy techniques. These alloys were rapidly solidified using the chill block melt spinning technique and the rapidly solidified microstructures were characterized using electron microscopy. The spinning technique and the rapidly solidified microstructures was assessed following heat treatments at 1033 and 1272 K. Rapidly solidified material of three alloys was reduced to particulate form and consolidated using hot isostatic pressing (HIP). The consolidated materials were also characterized using microscopy techniques. In order to evaluate the relative strengths of the consolidated alloys, compression tests were performed at room temperature and 1033 K on samples of as-HIPed and HIPed plus solution treated material. Yield strength, porosity, and oxidation resistance characteristics are given and compared.

Low cost MATLAB-based pulse oximeter for deployment in research and development applications.

PubMed

Shokouhian, M; Morling, R C S; Kale, I

2013-01-01

Problems such as motion artifact and effects of ambient lights have forced developers to design different signal processing techniques and algorithms to increase the reliability and accuracy of the conventional pulse oximeter device. To evaluate the robustness of these techniques, they are applied either to recorded data or are implemented on chip to be applied to real-time data. Recorded data is the most common method of evaluating however it is not as reliable as real-time measurements. On the other hand, hardware implementation can be both expensive and time consuming. This paper presents a low cost MATLAB-based pulse oximeter that can be used for rapid evaluation of newly developed signal processing techniques and algorithms. Flexibility to apply different signal processing techniques, providing both processed and unprocessed data along with low implementation cost are the important features of this design which makes it ideal for research and development purposes, as well as commercial, hospital and healthcare application.

Assessing a novel polymer-wick based electrode for EEG neurophysiological research.

PubMed

Pasion, Rita; Paiva, Tiago O; Pedrosa, Paulo; Gaspar, Hugo; Vasconcelos, Beatriz; Martins, Ana C; Amaral, Maria H; Nóbrega, João M; Páscoa, Ricardo; Fonseca, Carlos; Barbosa, Fernando

2016-07-15

The EEG technique has decades of valid applications in clinical and experimental neurophysiology. EEG equipment and data analysis methods have been characterized by remarkable developments, but the skin-to-electrode signal transfer remains a challenge for EEG recording. A novel quasi-dry system - the polymer wick-based electrode - was developed to overcome the limitations of conventional dry and wet silver/silver-chloride (Ag/AgCl) electrodes for EEG recording. Nine participants completed an auditory oddball protocol with simultaneous EEG acquisition using both the conventional Ag/AgCl and the wick electrodes. Wick system successfully recorded the expected P300 modulation. Standard ERP analysis, residual random noise analysis, and single-trial analysis of the P300 wave were performed in order to compare signal acquired by both electrodes. It was found that the novel wick electrode performed similarly to the conventional Ag/AgCl electrodes. The developed wick electrode appears to be a reliable alternative for EEG research, representing a promising halfway alternative between wet and dry electrodes. Copyright © 2016 Elsevier B.V. All rights reserved.

UV shielding with visible transparency based properties of poly (styrene-co-acrylonitrile)/Ag doped ZnO nanocomposite

NASA Astrophysics Data System (ADS)

Singh, Rajender; Verma, Karan; Singh, Tejbir; Barman, P. B.; Sharma, Dheeraj

2018-02-01

Development of ultraviolet (UV) shielding with visible transparency based thermoplastic polymer nanocomposite (PNs) presents an important requisite in terms of their efficiency and cost. Present study contributed for the same approach by dispersion of Ag doped ZnO nanoparticles upto 10 wt% in poly (styrene-co-acrylonitrile) matrix by insitu emulsion polymerization method. The crystal and chemical structure of PNs has been analyzed by x-ray diffraction (XRD) and fourier infrared spectrometer (FTIR) techniques. The morphological and elemental information of synthesized nanomaterial has been studied by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) technique. The optical properties of PNs has been studied by UV-visible spectroscopy technique. The incorporation of nanoparticles in polymer matrix absorb the complete UV light with visible transparency. The present reported polymer nanocomposite (PNs) have tuned refractive index with UV blocking and visible transparency based properties which can serve as a viable alternative as compared to related conventional materials.

An Enzyme-Free Signal Amplification Technique for Ultrasensitive Colorimetric Assay of Disease Biomarkers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Haihang; Yang, Kuikun; Tao, Jing

Enzyme-based colorimetric assays have been widely used in research labs and clinical diagnosis for decades. Nevertheless, as constrained by the performance of enzymes, their detection sensitivity has not been substantially improved in recent years, which inhibits many critical applications such as early detection of cancers. In this work, we demonstrate an enzyme-free signal amplification technique, based on gold vesicles encapsulated with Pd-Ir nanoparticles as peroxidase mimics, for colorimetric assay of disease biomarkers with significantly enhanced sensitivity. This technique overcomes the intrinsic limitations of enzymes, thanks to the superior catalytic efficiency of peroxidase mimics and the efficient loading and release ofmore » these mimics. Using human prostate surface antigen as a model biomarker, we demonstrated that the enzyme-free assay could reach a limit of detection at the femtogram/mL level, which is over 10 3-fold lower than that of conventional enzyme-based assay when the same antibodies and similar procedure were used.« less

An Enzyme-Free Signal Amplification Technique for Ultrasensitive Colorimetric Assay of Disease Biomarkers

DOE PAGES

Ye, Haihang; Yang, Kuikun; Tao, Jing; ...

2017-01-30

Enzyme-based colorimetric assays have been widely used in research labs and clinical diagnosis for decades. Nevertheless, as constrained by the performance of enzymes, their detection sensitivity has not been substantially improved in recent years, which inhibits many critical applications such as early detection of cancers. In this work, we demonstrate an enzyme-free signal amplification technique, based on gold vesicles encapsulated with Pd-Ir nanoparticles as peroxidase mimics, for colorimetric assay of disease biomarkers with significantly enhanced sensitivity. This technique overcomes the intrinsic limitations of enzymes, thanks to the superior catalytic efficiency of peroxidase mimics and the efficient loading and release ofmore » these mimics. Using human prostate surface antigen as a model biomarker, we demonstrated that the enzyme-free assay could reach a limit of detection at the femtogram/mL level, which is over 10 3-fold lower than that of conventional enzyme-based assay when the same antibodies and similar procedure were used.« less