Investigating Arabic to Speakers of Other Languages (ASOL) Lecturers' Attitudes towards Utilizing Flipped Classroom Instruction (FCI): A Qualitative Study at Jordanian Public Universities

ERIC Educational Resources Information Center

Al rababah, Ibraheem Hasan; Rababah, Luqman

2017-01-01

Although Flipped Classroom Instruction (FCI) is not a new concept, the practice is relatively new in the Arab region, especially, in Jordan, where the face-to face approach is still widely used. This qualitative study examined the attitudes of Arabic language lecturers at three Jordanian public universities towards utilizing FCI in their…

77 FR 19610 - Marc Knapp, Inmate #-06450-015, FCI Safford, P.O. Box 9000, Safford, AZ 85548; Order Denying...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-02

... DEPARTMENT OF COMMERCE Bureau of Industry and Security Marc Knapp, Inmate --06450-015, FCI Safford, P.O. Box 9000, Safford, AZ 85548; Order Denying Export Privileges On September 13, 2011, in the U.S..., with the last known address at: Inmate --06450-015, FCI Safford, P.O. Box 9000, Safford, AZ 85548, and...

Functional recovery patterns in seriously injured automotive crash victims.

PubMed

McMurry, Timothy L; Poplin, Gerald S; Crandall, Jeff

2016-09-01

The functional capacity index (FCI) is designed to predict functional loss 12 months post-injury for each injury in the 2008 Abbreviated Injury Scale (AIS) manual on a scale from 0 (death) to 100 (full recovery), but FCI has never been validated. This study compared FCI predicted loss with patient-reported 12-month outcomes as measured through the Short Form 36 (SF-36) health assessment survey. Using follow-up data collected on 2,858 adult car crash occupants in the Crash Injury Research and Engineering Network (CIREN) database, we compared FCI predicted outcomes to occupants' Physical Component Summary (PCS) scores, which are weighted averages of the SF-36 items addressing physical function. Our analyses included descriptive statistics, plots of typical recovery patterns, and a mixed effects regression model that describes PCS as a function of FCI, demographics, comorbidities, and injury pattern while also adjusting for the occupants' pre-crash physical capabilities. We further examined injuries in patients who report a significant drop in PCS 12 months post-crash despite being predicted to fully recover. At baseline, the CIREN population exhibited PCS scores similar to the overall population (mean = 51.1, SD = 10.3). Twelve months post-crash, occupants with predicted impairment (FCI < 100) report a substantial decrease in physical function, and those who were predicted to fully recover still report some, albeit less, impairment. In the multivariate mixed-effects regression model, FCI is a strongly significant (P-value <.0001) predictor of PCS, with each 1-point drop in FCI predicting a 0.27-point drop in PCS. Maximum AIS severities in the head, spine, and lower extremity body regions were also significantly associated with PCS (P-values <.05). Among occupants who were expected to fully recover but who report a significant drop in PCS at 12 months, spinal fractures without cord involvement account for 5 of the 10 most common AIS 2+ injuries. FCI was associated with 12-month outcomes but may not adequately describe the recovery from some head, spine, and lower extremity injuries. Some occupants who were expected to recover still report functional loss 12 months post-injury.

Current food chain information provides insufficient information for modern meat inspection of pigs.

PubMed

Felin, Elina; Jukola, Elias; Raulo, Saara; Heinonen, Jaakko; Fredriksson-Ahomaa, Maria

2016-05-01

Meat inspection now incorporates a more risk-based approach for protecting human health against meat-borne biological hazards. Official post-mortem meat inspection of pigs has shifted to visual meat inspection. The official veterinarian decides on additional post-mortem inspection procedures, such as incisions and palpations. The decision is based on declarations in the food chain information (FCI), ante-mortem inspection and post-mortem inspection. However, a smooth slaughter and inspection process is essential. Therefore, one should be able to assess prior to slaughter which pigs are suitable for visual meat inspection only, and which need more profound inspection procedures. This study evaluates the usability of the FCI provided by pig producers and considered the possibility for risk ranking of incoming slaughter batches according to the previous meat inspection data and the current FCI. Eighty-five slaughter batches comprising 8954 fattening pigs were randomly selected at a slaughterhouse that receives animals from across Finland. The mortality rate, the FCI and the meat inspection results for each batch were obtained. The current FCI alone provided insufficient and inaccurate information for risk ranking purposes for meat inspection. The partial condemnation rate for a batch was best predicted by the partial condemnation rate calculated for all the pigs sent for slaughter from the same holding in the previous year (p<0.001) and by prior information on cough declared in the current FCI (p=0.02) statement. Training and information to producers are needed to make the FCI reporting procedures more accurate. Historical meat inspection data on pigs slaughtered from the same holdings and well-chosen symptoms/signs for reporting, should be included in the FCI to facilitate the allocation of pigs for visual inspection. The introduced simple scoring system can be easily used for additional information for directing batches to appropriate meat inspection procedures. To control the main biological public health hazards related to pork, serological surveillance should be done and the information obtained from analyses should be used as part of the FCI. Copyright © 2016 Elsevier B.V. All rights reserved.

On the Use of Two Versions of the Force Concept Inventory to Test Conceptual Understanding of Mechanics in Lao PDR

ERIC Educational Resources Information Center

Luangrath, Phimpho; Pettersson, Sune; Benckert, Sylvia

2011-01-01

In this study, we investigated why Laotian students had a low score, when they were tested by the Force Concept Inventory (FCI). About 400 first year university students answered the FCI or a Lao version of the FCI (LFCI) with the contexts of some questions changed. The students answered a questionnaire and 34 of the students were interviewed. The…

Frequency of consuming foods predicts changes in cravings for those foods during weight loss: The POUNDS Lost Study

PubMed Central

Apolzan, John W.; Myers, Candice A.; Champagne, Catherine M.; Beyl, Robbie A.; Raynor, Hollie A.; Anton, Stephen A.; Williamson, Donald A.; Sacks, Frank M.; Bray, George A.; Martin, Corby K.

2017-01-01

Objective Food cravings are thought to be the result of conditioning or pairing hunger with consumption of certain foods. Methods In a two-year weight loss trial, subjects were randomized to one of four diets that varied in macronutrient content. The Food Craving Inventory (FCI) was used to measure cravings at baseline, 6, and 24 months. Also, food intake was measured at those time points. To measure free-living consumption of food items measured in the FCI, items on the FCI were matched to the foods consumed from the food intake assessments. Secondarily, we analyzed the amount of food consumed on food intake assessments from foods on the FCI. Results 367 subjects who were overweight and obese were included. There was an association between change from baseline FCI item consumption and change in cravings at months 6 (p<0.001) and 24 (p<0.05). There was no association between change from baseline amount of energy consumed per FCI item and change in cravings. Conclusions Altering frequency of consuming craved foods is positively associated with cravings; however, changing the amount of foods consumed does not appear to alter cravings. These results support the conditioning model of food cravings and provide guidance on how to reduce food cravings. PMID:28618170

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

Lan, Keng-Hsueh; Shih, Yi-Sheng; Chang, Cheng Allen

Highlights: Black-Right-Pointing-Pointer EGFR-expressing epithelial cancers account for significant portion of cancer deaths. Black-Right-Pointing-Pointer EGF-EGFR signaling pathway is validated as an important anticancer drug target. Black-Right-Pointing-Pointer EGF and Fcy fusion protein (Fcy-hEGF) can bind to EGFR and convert 5-FC to 5-FU. Black-Right-Pointing-Pointer Fcy-hEGF combined with 5-FC preferentially inhibits EGFR-expressing cells viability. -- Abstract: Human epithelial cancers account for approximately 50% of all cancer deaths. This type of cancer is characterized by excessive activation and expression of the epidermal growth factor receptor (EGFR). The EGFR pathway is critical for cancer cell proliferation, survival, metastasis and angiogenesis. The EGF-EGFR signaling pathway has beenmore » validated as an important anticancer drug target. Increasing numbers of targeted therapies against this pathway have been either approved or are currently under development. Here, we adopted a prodrug system that uses 5-fluorocytosine (5-FC) and human EGF (hEGF) fused with yeast cytosine deaminase (Fcy) to target EGFR-overexpressing cancer cells and to convert 5-FC to a significantly more toxic chemotherapeutic, 5-fluorouracil (5-FU). We cloned and purified the Fcy-hEGF fusion protein from Pichia pastoris yeast. This fusion protein specifically binds to EGFR with a similar affinity as hEGF, approximately 10 nM. Fcy-hEGF binds tightly to A431 and MDA-MB-468 cells, which overexpress EGFR, but it binds with a lower affinity to MDA-MB-231 and MCF-7, which express lower levels of EGFR. Similarly, the viability of EGFR-expressing cells was suppressed by Fcy-hEGF in the presence of increasing concentrations of 5-FC, and the IC{sub 50} values for A431 and MDA-MB-468 were approximately 10-fold lower than those of MDA-MB-231 and MCF-7. This novel prodrug system, Fcy-hEGF/5-FC, might represent a promising addition to the available class of inhibitors that specifically target EGFR-expressing cancers.« less

Progress on DCLL Blanket Concept

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

Wong, Clement; Abdou, M.; Katoh, Yutai

2013-09-01

Under the US Fusion Nuclear Science and Technology Development program, we have selected the Dual Coolant Lead Lithium concept (DCLL) as a reference blanket, which has the potential to be a high performance DEMO blanket design with a projected thermal efficiency of >40%. Reduced activation ferritic/martensitic (RAF/M) steel is used as the structural material. The self-cooled breeder PbLi is circulated for power conversion and for tritium breeding. A SiC-based flow channel insert (FCI) is used as a means for magnetohydrodynamic pressure drop reduction from the circulating liquid PbLi and as a thermal insulator to separate the high-temperature PbLi (~700°C) frommore » the helium-cooled RAF/M steel structure. We are making progress on related R&D needs to address critical Fusion Nuclear Science and Facility (FNSF) and DEMO blanket development issues. When performing the function as the Interface Coordinator for the DCLL blanket concept, we had been developing the mechanical design and performing neutronics, structural and thermal hydraulics analyses of the DCLL TBM module. We had estimated the necessary ancillary equipment that will be needed at the ITER site and a detailed safety impact report has been prepared. This provided additional understanding of the DCLL blanket concept in preparation for the FNSF and DEMO. This paper will be a summary report on the progress of the DCLL TBM design and R&Ds for the DCLL blanket concept.« less

Magnetic resonance imaging volume of the angular gyri predicts financial skill deficits in people with amnestic mild cognitive impairment.

PubMed

Griffith, H Randall; Stewart, Christopher C; Stoeckel, Luke E; Okonkwo, Ozioma C; den Hollander, Jan A; Martin, Roy C; Belue, Katherine; Copeland, Jacquelynn N; Harrell, Lindy E; Brockington, John C; Clark, David G; Marson, Daniel C

2010-02-01

To better understand how brain atrophy in amnestic mild cognitive impairment (MCI) as measured using magnetic resonance imaging (MRI) volumetrics could affect instrumental activities of daily living (IADLs) such as financial abilities. Controlled, matched-sample, cross-sectional analysis regressing MRI volumetrics with financial performance measures. University medical and research center. Thirty-eight people with MCI and 28 older adult controls. MRI volumetric measurement of the hippocampi, angular gyri, precunei, and medial frontal lobes. Participants also completed neuropsychological tests and the Financial Capacity Instrument (FCI). Correlations were performed between FCI scores and MRI volumes in the group with MCI. People with MCI performed significantly below controls on the FCI and had significantly smaller hippocampi. Among people with MCI, performance on the FCI was moderately correlated with angular gyri and precunei volumes. Regression models demonstrated that angular gyrus volumes were predictive of FCI scores. Tests of mediation showed that measures of arithmetic and possibly attention partially mediated the relationship between angular gyrus volume and FCI score. Impaired financial abilities in amnestic MCI correspond with volume of the angular gyri as mediated by arithmetic knowledge. The findings suggest that early neuropathology within the lateral parietal region in MCI leads to a breakdown of cognitive abilities that affect everyday financial skills. The findings have implications for diagnosis and clinical care of people with MCI and AD.

Analyzing false positives of four questions in the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Yasuda, Jun-ichiro; Mae, Naohiro; Hull, Michael M.; Taniguchi, Masa-aki

2018-06-01

In this study, we analyze the systematic error from false positives of the Force Concept Inventory (FCI). We compare the systematic errors of question 6 (Q.6), Q.7, and Q.16, for which clearly erroneous reasoning has been found, with Q.5, for which clearly erroneous reasoning has not been found. We determine whether or not a correct response to a given FCI question is a false positive using subquestions. In addition to the 30 original questions, subquestions were introduced for Q.5, Q.6, Q.7, and Q.16. This modified version of the FCI was administered to 1145 university students in Japan from 2015 to 2017. In this paper, we discuss our finding that the systematic errors of Q.6, Q.7, and Q.16 are much larger than that of Q.5 for students with mid-level FCI scores. Furthermore, we find that, averaged over the data sample, the sum of the false positives from Q.5, Q.6, Q.7, and Q.16 is about 10% of the FCI score of a midlevel student.

Examining student performance in an introductory Physics for engineering course: A quantitative case study.

NASA Astrophysics Data System (ADS)

Valente, Diego; Savkar, Amit; Mokaya, Fridah; Wells, James

The Force Concept Inventory (FCI) has been analyzed and studied in various ways with regards to students' understanding of basic physics concepts. We present normalized learning gains and effect size calculations of FCI scores, taken in the context of large-scale classes in a 4-year public university and course instruction that incorporates elements of Just-In-Time teaching and active learning components. In addition, we will present here a novel way of using FCI pre- and post-test as a predictor of students' performance on midterm and final exams. Utilizing a taxonomy table of physics concepts, we will look at student performance broken down by topic, while also examining possible correlations between FCI post-test scores and other course assessments. College of Liberal Arts and Sciences (CLAS), UConn.

Rasch model based analysis of the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Planinic, Maja; Ivanjek, Lana; Susac, Ana

2010-06-01

The Force Concept Inventory (FCI) is an important diagnostic instrument which is widely used in the field of physics education research. It is therefore very important to evaluate and monitor its functioning using different tools for statistical analysis. One of such tools is the stochastic Rasch model, which enables construction of linear measures for persons and items from raw test scores and which can provide important insight in the structure and functioning of the test (how item difficulties are distributed within the test, how well the items fit the model, and how well the items work together to define the underlying construct). The data for the Rasch analysis come from the large-scale research conducted in 2006-07, which investigated Croatian high school students’ conceptual understanding of mechanics on a representative sample of 1676 students (age 17-18 years). The instrument used in research was the FCI. The average FCI score for the whole sample was found to be (27.7±0.4)% , indicating that most of the students were still non-Newtonians at the end of high school, despite the fact that physics is a compulsory subject in Croatian schools. The large set of obtained data was analyzed with the Rasch measurement computer software WINSTEPS 3.66. Since the FCI is routinely used as pretest and post-test on two very different types of population (non-Newtonian and predominantly Newtonian), an additional predominantly Newtonian sample ( N=141 , average FCI score of 64.5%) of first year students enrolled in introductory physics course at University of Zagreb was also analyzed. The Rasch model based analysis suggests that the FCI has succeeded in defining a sufficiently unidimensional construct for each population. The analysis of fit of data to the model found no grossly misfitting items which would degrade measurement. Some items with larger misfit and items with significantly different difficulties in the two samples of students do require further examination. The analysis revealed some problems with item distribution in the FCI and suggested that the FCI may function differently in non-Newtonian and predominantly Newtonian population. Some possible improvements of the test are suggested.

Declining financial capacity in mild cognitive impairment: A 1-year longitudinal study.

PubMed

Triebel, K L; Martin, R; Griffith, H R; Marceaux, J; Okonkwo, O C; Harrell, L; Clark, D; Brockington, J; Bartolucci, A; Marson, Daniel C

2009-09-22

To investigate 1-year change in financial capacity in relation to conversion from amnestic mild cognitive impairment (MCI) to dementia. Seventy-six cognitively healthy older controls, 25 patients with amnestic MCI who converted to Alzheimer-type dementia during the study period (MCI converters), and 62 patients with MCI who did not convert to dementia (MCI nonconverters) were administered the Financial Capacity Instrument (FCI) at baseline and 1-year follow-up. Performance on the FCI domain and global scores was compared within and between groups using multivariate repeated-measures analyses. At baseline, controls performed better than MCI converters and nonconverters on almost all FCI domains and on both FCI total scores. MCI converters performed below nonconverters on domains of financial concepts, cash transactions, bank statement management, and bill payment and on both FCI total scores. At 1-year follow-up, MCI converters showed significantly greater decline than controls and MCI nonconverters for the domain of checkbook management and for both FCI total scores. The domain of bank statement management showed a strong trend. For both the checkbook and bank statement domains, MCI converters showed declines in procedural skills, such as calculating the correct balance in a checkbook register, but not in conceptual understanding of a checkbook or a bank statement. Declining financial skills are detectable in patients with mild cognitive impairment (MCI) in the year before their conversion to Alzheimer disease. Clinicians should proactively monitor patients with MCI for declining financial skills and advise patients and families about appropriate interventions.

Comparing large lecture mechanics curricula using the Force Concept Inventory: A five thousand student study

NASA Astrophysics Data System (ADS)

Caballero, Marcos D.; Greco, Edwin F.; Murray, Eric R.; Bujak, Keith R.; Jackson Marr, M.; Catrambone, Richard; Kohlmyer, Matthew A.; Schatz, Michael F.

2012-07-01

The performance of over 5000 students in introductory calculus-based mechanics courses at the Georgia Institute of Technology was assessed using the Force Concept Inventory (FCI). Results from two different curricula were compared: a traditional mechanics curriculum and the Matter & Interactions (M&I) curriculum. Both were taught with similar interactive pedagogy. Post-instruction FCI averages were significantly higher for the traditional curriculum than for the M&I curriculum; the differences between curricula persist after accounting for factors such as pre-instruction FCI scores, grade point averages, and SAT scores. FCI performance on categories of items organized by concepts was also compared; traditional averages were significantly higher in each concept. We examined differences in student preparation between the curricula and found that the relative fraction of homework and lecture topics devoted to FCI force and motion concepts correlated with the observed performance differences. Concept inventories, as instruments for evaluating curricular reforms, are generally limited to the particular choice of content and goals of the instrument. Moreover, concept inventories fail to measure what are perhaps the most interesting aspects of reform: the non-overlapping content and goals that are not present in courses without reform.

Neurocognitive predictors of financial capacity in traumatic brain injury.

PubMed

Martin, Roy C; Triebel, Kristen; Dreer, Laura E; Novack, Thomas A; Turner, Crystal; Marson, Daniel C

2012-01-01

To develop cognitive models of financial capacity (FC) in patients with traumatic brain injury (TBI). Longitudinal design. Inpatient brain injury rehabilitation unit. Twenty healthy controls, and 24 adults with moderate-to-severe TBI were assessed at baseline (30 days postinjury) and 6 months postinjury. The FC instrument (FCI) and a neuropsychological test battery. Univariate correlation and multiple regression procedures were employed to develop cognitive models of FCI performance in the TBI group, at baseline and 6-month time follow-up. Three cognitive predictor models of FC were developed. At baseline, measures of mental arithmetic/working memory and immediate verbal memory predicted baseline FCI performance (R = 0.72). At 6-month follow-up, measures of executive function and mental arithmetic/working memory predicted 6-month FCI performance (R = 0.79), and a third model found that these 2 measures at baseline predicted 6-month FCI performance (R = 0.71). Multiple cognitive functions are associated with initial impairment and partial recovery of FC in moderate-to-severe TBI patients. In particular, arithmetic, working memory, and executive function skills appear critical to recovery of FC in TBI. The study results represent an initial step toward developing a neurocognitive model of FC in patients with TBI.

National Historic Preservation Act (NHPA) Section 106 Process: Florence Copper, Inc. (FCI)

EPA Pesticide Factsheets

Collection of National Historic Preservation Act (NHPA) documents relating to Public Notice of Intent to Issue a Class III Underground Injection Control Area Permit for Florence Copper, Inc. (FCI) - Florence, AZ (closed)

Core-core and core-valence correlation

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

1988-01-01

The effect of (1s) core correlation on properties and energy separations was analyzed using full configuration-interaction (FCI) calculations. The Be 1 S - 1 P, the C 3 P - 5 S and CH+ 1 Sigma + or - 1 Pi separations, and CH+ spectroscopic constants, dipole moment and 1 Sigma + - 1 Pi transition dipole moment were studied. The results of the FCI calculations are compared to those obtained using approximate methods. In addition, the generation of atomic natural orbital (ANO) basis sets, as a method for contracting a primitive basis set for both valence and core correlation, is discussed. When both core-core and core-valence correlation are included in the calculation, no suitable truncated CI approach consistently reproduces the FCI, and contraction of the basis set is very difficult. If the (nearly constant) core-core correlation is eliminated, and only the core-valence correlation is included, CASSCF/MRCI approached reproduce the FCI results and basis set contraction is significantly easier.

Industrial stator vane with sequential impingement cooling inserts

DOEpatents

Jones, Russell B; Fedock, John A; Goebel, Gloria E; Krueger, Judson J; Rawlings, Christopher K; Memmen, Robert L

2013-08-06

A turbine stator vane for an industrial engine, the vane having two impingement cooling inserts that produce a series of impingement cooling from the pressure side to the suction side of the vane walls. Each insert includes a spar with a row of alternating impingement cooling channels and return air channels extending in a radial direction. Impingement cooling plates cover the two sides of the insert and having rows of impingement cooling holes aligned with the impingement cooling channels and return air openings aligned with the return air channel.

Expanding the FCI to Eevaluate Conceptual Mastery of Energy, Momentum, and Rotational Dynamics

NASA Astrophysics Data System (ADS)

Chediak, Alex; Hay, Katrina

2010-03-01

Normalized gain on the Force Concept Inventory (FCI) has deservedly become a widely accepted assessment tool to evaluate conceptual mastery in a high school, college, or university-level mechanics course. Left out of this assessment, however, are important physics concepts typically presented in the same course. Conservation of energy and momentum as well as rotational motion receive scant (if any) coverage on the FCI (or, for that matter, the Mechanics Baseline Test). Yet these concepts are foundational for popular majors such as mechanical engineering, where high failure rates are often a concern. A revised assessment tool is presented, one that incorporates the strengths of the FCI (and preserves the straightforward multiple choice format), but assesses these other mechanics-related concepts. Ten additional questions are included, inspired in part by material from the Physics Education Group at the University of Washington and in part by the authors' own experiences with common student misperceptions. The questions are given as pre- and post tests at the authors' institutions, California Baptist University and Pacific Lutheran University, in both calculus-based and algebra-based mechanics courses, exploring breadth of applicability for our findings. We present normalized gain data for the traditional thirty FCI questions and for our ten additional questions.

Advantages of flow cytometry immunophenotyping for the diagnosis of central nervous system non-Hodgkin's lymphoma in AIDS patients.

PubMed

Subirá, D; Górgolas, M; Castañón, S; Serrano, C; Román, A; Rivas, F; Tomás, J F

2005-01-01

Neurological disorders are common in HIV-infected patients. Central nervous system (CNS) lymphoma should always be considered because it is an important cause of morbidity and mortality. To investigate the clinical utility of flow cytometry immunophenotyping (FCI) in diagnosing or discarding leptomeningeal involvement in HIV-infected patients and to compare its sensitivity with that of conventional cytological methods. Fifty-six cerebrospinal fluid (CSF) samples from 29 HIV-infected patients were independently evaluated by flow cytometry and cytology. The description of an aberrant immunophenotype was the criterion used to define the malignant nature of any CSF cell population. FCI and cytology gave concordant results for 48 of the 56 CSF samples studied: 37 were negative for malignancy and 11 had evidence of CNS lymphoma. Discordant results were obtained for eight CSF samples, and the accuracy of the FCI findings could be demonstrated for four CSF samples described as positive for malignancy according to the FCI criteria. A high level of agreement was found between the results obtained using the two methods, but FCI gave at least 25% higher sensitivity than conventional cytomorphological methods for the detection of malignant cells. This advantage suggests that, in case of negative flow cytometry results, disorders other than non-Hodgkin's lymphoma should be strongly considered.

Gender fairness within the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Traxler, Adrienne; Henderson, Rachel; Stewart, John; Stewart, Gay; Papak, Alexis; Lindell, Rebecca

2018-01-01

Research on the test structure of the Force Concept Inventory (FCI) has largely ignored gender, and research on FCI gender effects (often reported as "gender gaps") has seldom interrogated the structure of the test. These rarely crossed streams of research leave open the possibility that the FCI may not be structurally valid across genders, particularly since many reported results come from calculus-based courses where 75% or more of the students are men. We examine the FCI considering both psychometrics and gender disaggregation (while acknowledging this as a binary simplification), and find several problematic questions whose removal decreases the apparent gender gap. We analyze three samples (total Npre=5391 , Npost=5769 ) looking for gender asymmetries using classical test theory, item response theory, and differential item functioning. The combination of these methods highlights six items that appear substantially unfair to women and two items biased in favor of women. No single physical concept or prior experience unifies these questions, but they are broadly consistent with problematic items identified in previous research. Removing all significantly gender-unfair items halves the gender gap in the main sample in this study. We recommend that instructors using the FCI report the reduced-instrument score as well as the 30-item score, and that credit or other benefits to students not be assigned using the biased items.

Sequential cooling insert for turbine stator vane

DOEpatents

Jones, Russell B.; Krueger, Judson J.; Plank, William L.

2014-04-01

A sequential impingement cooling insert for a turbine stator vane that forms a double impingement for the pressure and suction sides of the vane or a triple impingement. The insert is formed from a sheet metal formed in a zigzag shape that forms a series of alternating impingement cooling channels with return air channels, where pressure side and suction side impingement cooling plates are secured over the zigzag shaped main piece. Another embodiment includes the insert formed from one or two blocks of material in which the impingement channels and return air channels are machined into each block.

Sequential cooling insert for turbine stator vane

DOEpatents

Jones, Russel B; Krueger, Judson J; Plank, William L

2014-11-04

A sequential impingement cooling insert for a turbine stator vane that forms a double impingement for the pressure and suction sides of the vane or a triple impingement. The insert is formed from a sheet metal formed in a zigzag shape that forms a series of alternating impingement cooling channels with return air channels, where pressure side and suction side impingement cooling plates are secured over the zigzag shaped main piece. Another embodiment includes the insert formed from one or two blocks of material in which the impingement channels and return air channels are machined into each block.

78 FR 49469 - Stephen Glen Guerra, Inmate #98595-279, FCI Yazoo City Medium, Federal Correctional Institution...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-14

... DEPARTMENT OF COMMERCE Bureau of Industry and Security Stephen Glen Guerra, Inmate 98595-279, FCI... Export Privileges On February 6, 2012, in the U.S. District Court, Western District of Texas, Stephen... conviction. [[Page 49470

Modeling the adiabatic connection in H2.

PubMed

Peach, Michael J G; Teale, Andrew M; Tozer, David J

2007-06-28

Full configuration interaction (FCI) data are used to quantify the accuracy of approximate adiabatic connection (AC) forms in describing the ground state potential energy curve of H2, within spin-restricted density functional theory (DFT). For each internuclear separation R, accurate properties of the AC are determined from large basis set FCI calculations. The parameters in the approximate AC form are then determined so as to reproduce these FCI values exactly, yielding an exchange-correlation energy expressed entirely in terms of FCI-derived quantities. This is combined with other FCI-derived energy components to give the total electronic energy; comparison with the FCI energy quantifies the accuracy of the AC form. Initial calculations focus on a [1/1]-Padé-based form. The potential energy curve determined using the procedure is a notable improvement over those from existing DFT functionals. The accuracy near equilibrium is quantified by calculating the bond length and vibrational wave numbers; errors in the latter are below 0.5%. The molecule dissociates correctly, which can be traced to the use of virtual orbital eigenvalues in the slope in the noninteracting limit, capturing static correlation. At intermediate R, the potential energy curve exhibits an unphysical barrier, similar to that noted previously using the random phase approximation. Alternative forms of the AC are also considered, paying attention to size extensivity and the behavior in the strong-interaction limit; none provide an accurate potential energy curve for all R, although good accuracy can be achieved near equilibrium. The study demonstrates how data from correlated ab initio calculations can provide valuable information about AC forms and highlight areas where further theoretical progress is required.

Validating two questions in the Force Concept Inventory with subquestions

NASA Astrophysics Data System (ADS)

Yasuda, Jun-ichiro; Taniguchi, Masa-aki

2013-06-01

In this study, we evaluate the structural validity of Q.16 and Q.7 in the Force Concept Inventory (FCI). We address whether respondents who answer Q.16 and Q.7 correctly actually have an understanding of the concepts of physics tested in the questions. To examine respondents’ levels of understanding, we use subquestions that test them on concepts believed to be required to answer the actual FCI questions. Our sample size comprises 111 respondents; we derive false-positive ratios for prelearners and postlearners and then statistically test the difference between them. We find a difference at the 0.05 significance level for both Q.16 and Q.7, implying that it is possible for postlearners to answer both questions without an understanding of the concepts of physics tested in the questions; therefore, the structures of Q.16 and Q.7 are invalid. In this study, we only evaluate the validity of these two FCI questions; we do not assess the validity of previous studies that have compared total FCI scores.

Applying a Force and Motion Learning Progression over an Extended Time Span using the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Fulmer, Gavin W.; Liang, Ling L.; Liu, Xiufeng

2014-11-01

This exploratory study applied a proposed force and motion learning progression (LP) to high-school and university students and to content involving both one- and two-dimensional force and motion situations. The Force Concept Inventory (FCI) was adapted, based on a previous content analysis and coding of the questions in the FCI in terms of the level descriptors of the LP. Using a Rasch measurement model and latent class analysis, students' responses were tested for fit with the proposed LP. Results indicated that the recoded FCI response options are generally consistent with a progression of difficulties as proposed in the LP, and that the students could be organized into different groups with progressively different levels of ability. However, reliability for the ability estimates was only moderate and response options at lower levels of the LP were not well differentiated. Implications for the assessments with LPs and revisions for both the FCI and the force and motion LP are also discussed.

Using the method of dominant incorrect answers with the FCI test to diagnose misconceptions held by first year college students

NASA Astrophysics Data System (ADS)

Bani-Salameh, Hisham N.

2017-01-01

We started this work with the goal of detecting misconceptions held by our students about force and motion. A total of 341 students participated in this study by taking the force concept inventory (FCI) test both before and after receiving instructions about force or motion. The data from this study were analysed using different statistical techniques with results from frequencies and the dominant incorrect answer reported in this paper. All misconceptions reported in the original paper of the designers of the FCI test (Hestenes et al 1992 Phys. Teach. 30 141-58) were examined and the results are reported. Only pre test results are reported in this paper leaving post data for future work. We used the modified version of the FCI containing 30 questions and therefore used the revised list of misconceptions. Problems with impetus and active force are among the most dominant ones found with the full list reported in this paper.

Phase transitions and adiabatic preparation of a fractional Chern insulator in a boson cold-atom model

NASA Astrophysics Data System (ADS)

Motruk, Johannes; Pollmann, Frank

2017-10-01

We investigate the fate of hardcore bosons in a Harper-Hofstadter model which was experimentally realized by Aidelsburger et al. [Nat. Phys. 11, 162 (2015), 10.1038/nphys3171] at half-filling of the lowest band. We discuss the stability of an emergent fractional Chern insulator (FCI) state in a finite region of the phase diagram that is separated from a superfluid state by a first-order transition when tuning the band topology following the protocol used in the experiment. Since crossing a first-order transition is unfavorable for adiabatically preparing the FCI state, we extend the model to stabilize a featureless insulating state. The transition between this phase and the topological state proves to be continuous, providing a path in parameter space along which an FCI state could be adiabatically prepared. To further corroborate this statement, we perform time-dependent DMRG calculations which demonstrate that the FCI state may indeed be reached by adiabatically tuning a simple product state.

Personality types and student performance in an introductory physics course

NASA Astrophysics Data System (ADS)

Harlow, Jason J. B.; Harrison, David M.; Justason, Michael; Meyertholen, Andrew; Wilson, Brian

2017-12-01

We measured the personality type of the students in a large introductory physics course of mostly life science students using the True Colors instrument. We found large correlations of personality type with performance on the precourse Force Concept Inventory (FCI), both term tests, the postcourse FCI, and the final examination. We also saw correlations with the normalized gain on the FCI. The personality profile of the students in this course is very different from the profile of the physics faculty and graduate students, and also very different from the profile of students taking the introductory physics course intended for physics majors and specialists.

Turbine airfoil having near-wall cooling insert

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

Martin, Jr., Nicholas F.; Wiebe, David J.

A turbine airfoil is provided with at least one insert positioned in a cavity in an airfoil interior. The insert extends along a span-wise extent of the turbine airfoil and includes first and second opposite faces. A first near-wall cooling channel is defined between the first face and a pressure sidewall of an airfoil outer wall. A second near-wall cooling channel is defined between the second face and a suction sidewall of the airfoil outer wall. The insert is configured to occupy an inactive volume in the airfoil interior so as to displace a coolant flow in the cavity towardmore » the first and second near-wall cooling channels. A locating feature engages the insert with the outer wall for supporting the insert in position. The locating feature is configured to control flow of the coolant through the first or second near-wall cooling channel.« less

The Facilities Condition Index: A Useful Tool for Capital Asset Planning.

ERIC Educational Resources Information Center

Briselden, Don J.; Cain, David A.

2001-01-01

Describes the development and history of the Facilities Condition Index (FCI) and its use in rating a facility's condition and measuring the amount of deferred maintenance needed. Also discusses the FCI's position within the Strategic Assessment Model and its usefulness to facilities managers. (GR)

Bioliteracy and Teaching Efficacy: What Biologists Can Learn from Physicists

ERIC Educational Resources Information Center

Klymkowsky, Michael W.; Garvin-Doxas, Kathy; Zeilik, Michael

2003-01-01

The introduction of the Force Concept Inventory (FCI) by David Hestenes and colleagues in 1992 produced a remarkable impact within the community of physics teachers. An instrument to measure student comprehension of the Newtonian concept of force, the FCI demonstrates that active learning leads to far superior student conceptual learning than…

Personality Types and Student Performance in an Introductory Physics Course

ERIC Educational Resources Information Center

Harlow, Jason J. B.; Harrison, David M.; Justason, Michael; Meyertholen, Andrew; Wilson, Brian

2017-01-01

We measured the personality type of the students in a large introductory physics course of mostly life science students using the True Colors instrument. We found large correlations of personality type with performance on the precourse Force Concept Inventory (FCI), both term tests, the postcourse FCI, and the final examination. We also saw…

Vortex-dislodged cells from bone marrow trephine biopsy yield satisfactory results for flow cytometric immunophenotyping.

PubMed

Bommannan, K; Sachdeva, M U S; Gupta, M; Bose, P; Kumar, N; Sharma, P; Naseem, S; Ahluwalia, J; Das, R; Varma, N

2016-10-01

A good bone marrow (BM) sample is essential in evaluating many hematologic disorders. An unsuccessful BM aspiration (BMA) procedure precludes a successful flow cytometric immunophenotyping (FCI) in most hematologic malignancies. Apart from FCI, most ancillary diagnostic techniques in hematology are less informative. We describe the feasibility of FCI in vortex-dislodged cell preparation obtained from unfixed trephine biopsy (TB) specimens. In pancytopenic patients and dry tap cases, routine diagnostic BMA and TB samples were complemented by additional trephine biopsies. These supplementary cores were immediately transferred into sterile tubes filled with phosphate-buffered saline, vortexed, and centrifuged. The cell pellet obtained was used for flow cytometric immunophenotyping. Of 7955 BMAs performed in 42 months, 34 dry tap cases were eligible for the study. Vortexing rendered a cell pellet in 94% of the cases (32 of 34), and FCI rendered a rapid diagnosis in 100% of the cases (32 of 32) where cell pellets were available. We describe an efficient procedure which could be effectively utilized in resource-limited centers and reduce the frequency of repeat BMA procedures. © 2016 John Wiley & Sons Ltd.

Experimental Validation of the Half-Length Force Concept Inventory

ERIC Educational Resources Information Center

Han, Jing; Koenig, Kathleen; Cui, Lili; Fritchman, Joseph; Li, Dan; Sun, Wanyi; Fu, Zhao; Bao, Lei

2016-01-01

In a recent study, the 30-question Force Concept Inventory (FCI) was theoretically split into two 14-question "half-length" tests (HFCIs) covering the same set of concepts and producing mean scores that can be equated to those of the original FCI. The HFCIs require less administration time and reduce test-retest issues when different…

Examining Evolving Performance on the Force Concept Inventory Using Factor Analysis

ERIC Educational Resources Information Center

Semak, M. R.; Dietz, R. D.; Pearson, R. H.; Willis, C. W

2017-01-01

The application of factor analysis to the "Force Concept Inventory" (FCI) has proven to be problematic. Some studies have suggested that factor analysis of test results serves as a helpful tool in assessing the recognition of Newtonian concepts by students. Other work has produced at best ambiguous results. For the FCI administered as a…

Exploratory Factor Analysis of a Force Concept Inventory Data Set

ERIC Educational Resources Information Center

Scott, Terry F.; Schumayer, Daniel; Gray, Andrew R.

2012-01-01

We perform a factor analysis on a "Force Concept Inventory" (FCI) data set collected from 2109 respondents. We address two questions: the appearance of conceptual coherence in student responses to the FCI and some consequences of this factor analysis on the teaching of Newtonian mechanics. We will highlight the apparent conflation of Newton's…

The topogenic function of S4 promotes membrane insertion of the voltage-sensor domain in the KvAP channel.

PubMed

Mishima, Eriko; Sato, Yoko; Nanatani, Kei; Hoshi, Naomi; Lee, Jong-Kook; Schiller, Nina; von Heijne, Gunnar; Sakaguchi, Masao; Uozumi, Nobuyuki

2016-12-01

Voltage-dependent K + (K V ) channels control K + permeability in response to shifts in the membrane potential. Voltage sensing in K V channels is mediated by the positively charged transmembrane domain S4. The best-characterized K V channel, KvAP, lacks the distinct hydrophilic region corresponding to the S3-S4 extracellular loop that is found in other K + channels. In the present study, we evaluated the topogenic properties of the transmembrane regions within the voltage-sensing domain in KvAP. S3 had low membrane insertion activity, whereas S4 possessed a unique type-I signal anchor (SA-I) function, which enabled it to insert into the membrane by itself. S4 was also found to function as a stop-transfer signal for retention in the membrane. The length and structural nature of the extracellular S3-S4 loop affected the membrane insertion of S3 and S4, suggesting that S3 membrane insertion was dependent on S4. Replacement of charged residues within the transmembrane regions with residues of opposite charge revealed that Asp 72 in S2 and Glu 93 in S3 contributed to membrane insertion of S3 and S4, and increased the stability of S4 in the membrane. These results indicate that the SA-I function of S4, unique among K + channels studied to date, promotes the insertion of S3 into the membrane, and that the charged residues essential for voltage sensing contribute to the membrane-insertion of the voltage sensor domain in KvAP. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

Opto-mechanical design of the MTG FCI spectral separation assembly

NASA Astrophysics Data System (ADS)

Riguet, François; Brousse, Emmanuel; Carel, Jean-Louis; Cottenye, Justine; Harmann, David; Joncour, Marc; Makhlouf, Houssine; Mouricaud, Daniel; Oussalah, Meihdi; Rodolfo, Jacques

2015-09-01

The Spectral Separation Assembly is a key component of the Flexible Combined Imager, an instrument that will be on-board Meteosat Third Generation. It splits the input beam coming from the telescope into five spectral groups, for a total of 16 channels, from 0.4 to 13.3 μm. It comprises a set of four dichroics separators followed by four collimating optics for the infrared spectral groups, which feed the cold imaging optics. The visible spectral group is directly imaged on a detector. This paper presents the optical design of the assembly, the mechanical mounting of the optical components, and the coatings developed for the dichroics, mirrors and lenses.

Combination of a fusogenic glycoprotein, prodrug activation, and oncolytic herpes simplex virus for enhanced local tumor control.

PubMed

Simpson, Guy R; Han, Ziqun; Liu, Binlei; Wang, Yibing; Campbell, Gregor; Coffin, Robert S

2006-05-01

We have previously developed an oncolytic herpes simplex virus-1 based on a clinical virus isolate, which was deleted for ICP34.5 to provide tumor selected replication and ICP47 to increase antigen presentation as well as tumor selective virus replication. A phase I/II clinical trial using a version of this virus expressing granulocyte macrophage colony-stimulating factor has shown promising results. The work reported here aimed to develop a version of this virus in which local tumor control was further increased through the combined expression of a highly potent prodrug activating gene [yeast cytosine deaminase/uracil phospho-ribosyltransferase fusion (Fcy::Fur)] and the fusogenic glycoprotein from gibbon ape leukemia virus (GALV), which it was hoped would aid the spread of the activated prodrug through the tumor. Viruses expressing the two genes individually or in combination were constructed and tested, showing (a) GALV and/or Fcy::Fur expression did not affect virus growth; (b) GALV expression causes cell fusion and increases the tumor cell killing at least 30-fold in vitro and tumor shrinkage 5- to 10-fold in vivo; (c) additional expression of Fcy::Fur combined with 5-fluorocytosine administration improves tumor shrinkage further. These results indicate, therefore, that the combined expression of the GALV protein and Fcy::Fur provides a highly potent oncolytic virus with improved capabilities for local tumor control. It is intended to enter the GALV/Fcy::Fur expressing virus into clinical development for the treatment of tumor types, such as pancreatic or lung cancer, where local control would be anticipated to be clinically advantageous.

[Dental fluorosis prevalence in Mexican localities of 27 states and the D.F.: six years after the publication of the Salt Fluoridation Mexican Official Regulation].

PubMed

Betancourt-Lineares, Armandor; Irigoyen-Camacho, María Esther; Mejía-González, Adriana; Zepeda-Zapeda, Marco; Sánchez-Pérez, Leonor

2013-01-01

To identify the prevalence and severity of dental fluorosis in communities located in 28 states of Mexico. The National Dental Caries Survey 2001 (NDCS2001) data base was analyzed. The information of 26,893 students, ages 12 and 15 years old, of 27 states and the Federal District was examined. Dean's dental fluorosis index was applied by standardized examiners. The fluorosis prevalence and the Community Fluorosis Index (FCI) were calculated. The fluorosis prevalence was 27.9% (95% CI 24.4, 28.5). A statistical significance difference in the fluorosis prevalence was observed among the states studied (p < 0.0001). The lowest prevalence was detected in Morelos (3.2%) and the highest in Durango (88.8%). In 18 (64.3%) of the states included more than 90% of the participants showed very mild or lower levels of the dental fluorosis index. A low level of the FCI was found in the localities belonging to 19 (67.9%) of the states studied (FCI < 0.4). The lowest FCI was found in Colima, Yucatán and Morelos. The highest FCI were found in Durango, Zacatecas, Aguascalientes and San Luis Potosí (1 ≤ ICF). This information indicates that in these states dental fluorosis is a public health problem. Two-thirds of the states had localities with low prevalence of dental fluorosis; however, approximately, one-third of the states investigated the fluorosis levels showed the need of a reduction in fluoride exposure among the young population.

Teaching Assistants' Performance at Identifying Common Introductory Student Difficulties in Mechanics Revealed by the Force Concept Inventory

ERIC Educational Resources Information Center

Maries, Alexandru; Singh, Chandralekha

2016-01-01

The Force Concept Inventory (FCI) has been widely used to assess student understanding of introductory mechanics concepts by a variety of educators and physics education researchers. One reason for this extensive use is that many of the items on the FCI have strong distractor choices which correspond to students' alternate conceptions in…

78 FR 49470 - Adrian Jesus Reyna, Inmate Number #80629-280, FCI Bastrop, Federal Correctional Institution, P.O...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-14

... DEPARTMENT OF COMMERCE Bureau of Industry and Security Adrian Jesus Reyna, Inmate Number 80629-280... Privileges On January 27, 2012, in the U.S. District Court, Western District of Texas, Adrian Jesus Reyna.... Until January 27, 2022, Adrian Jesus Reyna, with a last known address at: Inmate Number 80629-280, FCI...

Dividing the Force Concept Inventory into Two Equivalent Half-Length Tests

ERIC Educational Resources Information Center

Han, Jing; Bao, Lei; Chen, Li; Cai, Tianfang; Pi, Yuan; Zhou, Shaona; Tu, Yan; Koenig, Kathleen

2015-01-01

The Force Concept Inventory (FCI) is a 30-question multiple-choice assessment that has been a building block for much of the physics education research done today. In practice, there are often concerns regarding the length of the test and possible test-retest effects. Since many studies in the literature use the mean score of the FCI as the…

Correlation of understanding of physics and psychological symptoms among high-school students in Greece

NASA Astrophysics Data System (ADS)

Aggeliki, Anagnostopoulou; Miltiades, Kyprianou; Antigoni-Elisavet, Rota; Evangelia, Pavlatou; Loizos, Zaphiris

2017-09-01

Depression may essentially influence cognitive function contributing to poor school performance. The present study undertakes to determine the existence and strength of correlation between depressive symptomatology and other mental conditions with the acquired level of understanding of Newtonian physics taught in schools. The current study recruited 490 students (262 girls, 228 boys) attending the first semester of the Greek Second Grade of General Lyceum School. Force Concept Inventory (FCI) tested the depth of the students’ understanding of Newtonian Physics. Symptom Checklist-90-R assessed general mental status. The tests took place in the classroom during a 1 h session. Low FCI scores significantly correlated with mental conditions, with depression ranking first. Girls had higher scores in all nine symptoms scales of SCL-90 and lower FCI scores. Stepwise regression models proved that the gender effect on FCI could be effectively explained through the significant effect of depression. An understanding of Newtonian physics among high school students may be restricted by common problematic mental conditions, with depression being the greatest among all. Further research, using a more systematic approach to measure depression among adolescents with poor understanding of physics, would help to elucidate the nature of the effect.

Eye-tracking of visual attention in web-based assessment using the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Han, Jing; Chen, Li; Fu, Zhao; Fritchman, Joseph; Bao, Lei

2017-07-01

This study used eye-tracking technology to investigate students’ visual attention while taking the Force Concept Inventory (FCI) in a web-based interface. Eighty nine university students were randomly selected into a pre-test group and a post-test group. Students took the 30-question FCI on a computer equipped with an eye-tracker. There were seven weeks of instruction between the pre- and post-test data collection. Students’ performance on the FCI improved significantly from pre-test to post-test. Meanwhile, the eye-tracking results reveal that the time students spent on taking the FCI test was not affected by student performance and did not change from pre-test to post-test. Analysis of students’ attention to answer choices shows that on the pre-test students primarily focused on the naïve choices and ignored the expert choices. On the post-test, although students had shifted their primary attention to the expert choices, they still kept a high level of attention to the naïve choices, indicating significant conceptual mixing and competition during problem solving. Outcomes of this study provide new insights on students’ conceptual development in learning physics.

Role of fuel carbon intensity in achieving 2050 greenhouse gas reduction goals within the light-duty vehicle sector.

PubMed

Melaina, M; Webster, K

2011-05-01

Recent U.S. climate change policy developments include aggressive proposals to reduce greenhouse gas emissions, including cap-and-trade legislation with a goal of an 83% reduction below 2005 levels by 2050. This study examines behavioral and technological changes required to achieve this reduction within the light-duty vehicle (LDV) sector. Under this "fair share" sectoral assumption, aggressive near-term actions are necessary in three areas: vehicle miles traveled (VMT), vehicle fuel economy (FE), and fuel carbon intensity (FCI). Two generic scenarios demonstrate the important role of FCI in meeting the 2050 goal. The first scenario allows deep reductions in FCI to compensate for relatively modest FE improvements and VMT reductions. The second scenario assumes optimistic improvements in FE, relatively large reductions in VMT and less aggressive FCI reductions. Each generic scenario is expanded into three illustrative scenarios to explore the theoretical implications of meeting the 2050 goal by relying exclusively on biofuels and hybrid vehicles, biofuels and plug-in hybrid vehicles, or hydrogen fuel cell electric vehicles. These scenarios inform a discussion of resource limitations, technology development and deployment challenges, and policy goals required to meet the 2050 GHG goal for LDVs.

The design and development of the father-child instrument (FCI) for assessing the characteristics of fathers' availability and engagement with their preschool children.

PubMed

Halme, Nina; Tarkka, Marja-Terttu; Paavilainen, Eija; Nummi, Tapio; Astedt-Kurki, Päivi

2010-06-01

Despite the fact that father-child involvement has extensive effects on the health and well-being of the family, there is a paucity of research on fathers' presence in health care research. The design and development of an instrument for assessing the characteristics of fathers' availability and engagement with their preschool-aged children in Finland is presented. Data collection was undertaken in two separate periods involving 263 and 821 fathers. Results indicate that the father-child instrument (FCI) is ready for use in research seeking to assess fathers' availability and engagement with their preschoolers. Further research is nonetheless required to assess the potential for a more sensitive interaction and for the generalization of the FCI.

Oxidation promotes insertion of the CLIC1 chloride intracellular channel into the membrane.

PubMed

Goodchild, Sophia C; Howell, Michael W; Cordina, Nicole M; Littler, Dene R; Breit, Samuel N; Curmi, Paul M G; Brown, Louise Jennifer

2009-12-01

Members of the chloride intracellular channel (CLIC) family exist primarily as soluble proteins but can also auto-insert into cellular membranes to form ion channels. While little is known about the process of CLIC membrane insertion, a unique feature of mammalian CLIC1 is its ability to undergo a dramatic structural metamorphosis between a monomeric glutathione-S-transferase homolog and an all-helical dimer upon oxidation in solution. Whether this oxidation-induced metamorphosis facilitates CLIC1 membrane insertion is unclear. In this work, we have sought to characterise the role of oxidation in the process of CLIC1 membrane insertion. We examined how redox conditions modify the ability of CLIC1 to associate with and insert into the membrane using fluorescence quenching studies and a sucrose-loaded vesicle sedimentation assay to measure membrane binding. Our results suggest that oxidation of monomeric CLIC1, in the presence of membranes, promotes insertion into the bilayer more effectively than the oxidised CLIC1 dimer.

Insertable fluid flow passage bridgepiece and method

DOEpatents

Jones, Daniel O.

2000-01-01

A fluid flow passage bridgepiece for insertion into an open-face fluid flow channel of a fluid flow plate is provided. The bridgepiece provides a sealed passage from a columnar fluid flow manifold to the flow channel, thereby preventing undesirable leakage into and out of the columnar fluid flow manifold. When deployed in the various fluid flow plates that are used in a Proton Exchange Membrane (PEM) fuel cell, bridgepieces of this invention prevent mixing of reactant gases, leakage of coolant or humidification water, and occlusion of the fluid flow channel by gasket material. The invention also provides a fluid flow plate assembly including an insertable bridgepiece, a fluid flow plate adapted for use with an insertable bridgepiece, and a method of manufacturing a fluid flow plate with an insertable fluid flow passage bridgepiece.

Applying a Force and Motion Learning Progression over an Extended Time Span Using the Force Concept Inventory

ERIC Educational Resources Information Center

Fulmer, Gavin W.; Liang, Ling L.; Liu, Xiufeng

2014-01-01

This exploratory study applied a proposed force and motion learning progression (LP) to high-school and university students and to content involving both one- and two-dimensional force and motion situations. The Force Concept Inventory (FCI) was adapted, based on a previous content analysis and coding of the questions in the FCI in terms of the…

Using the Method of Dominant Incorrect Answers with the FCI Test to Diagnose Misconceptions Held by First Year College Students

ERIC Educational Resources Information Center

Bani-Salameh, Hisham N.

2017-01-01

We started this work with the goal of detecting misconceptions held by our students about force and motion. A total of 341 students participated in this study by taking the force concept inventory (FCI) test both before and after receiving instructions about force or motion. The data from this study were analysed using different statistical…

The influence of restrained and external eating patterns on overeating.

PubMed

Burton, Pat; Smit, Hendrik J; Lightowler, Helen J

2007-07-01

Eating in response to an increasingly obesogenic environment has been strongly implicated as a salient aspect of eating behaviour, arguably influenced by learning and experience. Interindividual differences in susceptibility to weight gain may be due, in part, to variability in response to environmental triggers. The phenomenon of food craving may also be an important factor influencing appetite control. The present study tested a model, in which food craving was hypothesised to be an intervening causal variable, on a causal pathway between responsivity to environmental cues and the development of obesity. One hundred and twenty four participants (aged 21-71 years, 83 females and 41 males) completed the study. Participants completed the Dutch eating behaviour questionnaire (DEBQ), measuring external eating (externality), emotional eating (emotionality) and restrained eating behaviour (restraint), and an adapted form of the food craving inventory (FCI), assessing cravings for carbohydrate, fats, sweets and fast food fats, in addition to total food cravings. Initial analysis showed positive correlations between FCI-tot and body mass index (BMI), FCI-fats and BMI and FCI-fast food fats and BMI in both men and women, and between FCI-carbohydrates and BMI in men only. Multiple regression analyses showed externality as the principal predictor of food craving, which was greater in males compared to females, but differential for different food groups between genders. Restrained eating and cravings for fats and fast food fats were negatively associated in women only. As predicted, total cravings, and cravings for fats and fast food foods mediated the positive association between external eating and BMI. It is concluded that appetitive response to external cues as an important risk factor in appetite control is mediated through cravings for particular food groups and is gender-dependent.

Food cravings among Brazilian population.

PubMed

Queiroz de Medeiros, Anna Cecília; Pedrosa, Lucia de Fatima Campos; Yamamoto, Maria Emilia

2017-01-01

This study aimed to develop and validate a Brazilian version of the Food Craving Inventory (FCI-Br), adapted to the cultural-gastronomic context of Brazil, and to explore this behavior among adult Brazilians. The Study 1 population consisted of 453 adults from all regions of Brazil. Participants responded to a preliminary form of the instrument online. Exploratory factor analysis revealed an FCI-Br presenting 23 items and three factors: High Fat, Sweet Food and Traditional Meal. The FCI-Br overall reliability was considered adequate (α = 0.82), as were each of the sub-scales. The food items receiving higher average scores from the application of the instrument were chocolate (3.14 ± 1.28; women) and bread (2.94 ± 1.44, men). A significant association was observed between the specific-craving for Sweet Food and female respondents. Most participants reported experiencing more frequent episodes of food craving when alone (68.0%; n = 391) and during the afternoon (32.2%; n = 127) or evening (43.8%; n = 173) hours. Application of the FCI-Br in a population of 649 university students (Study 2) demonstrated a good adjustment of the model developed according to the Confirmatory factor analysis (χ 2 /gl = 2.82, CFI = 0.94; TLI = 0.93; RMSEA = 0.06). The current findings indicate that the FCI-Br has adequate psychometric properties to measure craving behavior with respect to specific food groups in the resident population of Brazil. The results of this study also shed light on the importance of considering the cultural diversity of a population when investigating eating behaviors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification of CD56 and CD57 by flow cytometry in Ewing's sarcoma or primitive neuroectodermal tumor.

PubMed

Gardner, L J; Polski, J M; Fallon, R; Dunphy, C H

1998-07-01

CD56 and CD57 are commonly considered as natural killer and neuroectodermal markers, but their expression has been identified in a wide spectrum of neoplasms including some cases of Ewing's sarcoma (ES) and primitive neuroectodermal tumor (PNET). We report two cases of small, round blue cell tumor (SRBCT), in which flow cytometry immunophenotyping (FCI) detected strong expression of CD56 and CD57 (one case). Immunohistochemical staining with Leu-19 and Leu-7 confirmed the FI results. Although CD56 and CD57 expression is consistent with ES/PNET, it can be potentially misleading if results of FCI are interpreted in the absence of other findings. These cases suggest the utility of FCI in undifferentiated SRBCT. The literature on CD56 and CD57 expression in ES/PNET is reviewed and discussed.

Sequential cooling insert for turbine stator vane

DOEpatents

Jones, Russel B

2017-04-04

A sequential flow cooling insert for a turbine stator vane of a small gas turbine engine, where the impingement cooling insert is formed as a single piece from a metal additive manufacturing process such as 3D metal printing, and where the insert includes a plurality of rows of radial extending impingement cooling air holes alternating with rows of radial extending return air holes on a pressure side wall, and where the insert includes a plurality of rows of chordwise extending second impingement cooling air holes on a suction side wall. The insert includes alternating rows of radial extending cooling air supply channels and return air channels that form a series of impingement cooling on the pressure side followed by the suction side of the insert.

Core-core and core-valence correlation

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

1988-01-01

The effect of 1s core correlation on properties and energy separations are analyzed using full configuration-interaction (FCI) calculations. The Be1S - 1P, the C 3P - 5S,m and CH(+) 1Sigma(+) - 1Pi separations, and CH(+) spectroscopic constants, dipole moment, and 1Sigma(+) - 1Pi transition dipole moment have been studied. The results of the FCI calculations are compared to those obtained using approximate methods.

An item response curves analysis of the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Morris, Gary A.; Harshman, Nathan; Branum-Martin, Lee; Mazur, Eric; Mzoughi, Taha; Baker, Stephen D.

2012-09-01

Several years ago, we introduced the idea of item response curves (IRC), a simplistic form of item response theory (IRT), to the physics education research community as a way to examine item performance on diagnostic instruments such as the Force Concept Inventory (FCI). We noted that a full-blown analysis using IRT would be a next logical step, which several authors have since taken. In this paper, we show that our simple approach not only yields similar conclusions in the analysis of the performance of items on the FCI to the more sophisticated and complex IRT analyses but also permits additional insights by characterizing both the correct and incorrect answer choices. Our IRC approach can be applied to a variety of multiple-choice assessments but, as applied to a carefully designed instrument such as the FCI, allows us to probe student understanding as a function of ability level through an examination of each answer choice. We imagine that physics teachers could use IRC analysis to identify prominent misconceptions and tailor their instruction to combat those misconceptions, fulfilling the FCI authors' original intentions for its use. Furthermore, the IRC analysis can assist test designers to improve their assessments by identifying nonfunctioning distractors that can be replaced with distractors attractive to students at various ability levels.

Cryo-EM structure of lysenin pore elucidates membrane insertion by an aerolysin family protein

NASA Astrophysics Data System (ADS)

Bokori-Brown, Monika; Martin, Thomas G.; Naylor, Claire E.; Basak, Ajit K.; Titball, Richard W.; Savva, Christos G.

2016-04-01

Lysenin from the coelomic fluid of the earthworm Eisenia fetida belongs to the aerolysin family of small β-pore-forming toxins (β-PFTs), some members of which are pathogenic to humans and animals. Despite efforts, a high-resolution structure of a channel for this family of proteins has been elusive and therefore the mechanism of activation and membrane insertion remains unclear. Here we determine the pore structure of lysenin by single particle cryo-EM, to 3.1 Å resolution. The nonameric assembly reveals a long β-barrel channel spanning the length of the complex that, unexpectedly, includes the two pre-insertion strands flanking the hypothetical membrane-insertion loop. Examination of other members of the aerolysin family reveals high structural preservation in this region, indicating that the membrane-insertion pathway in this family is conserved. For some toxins, proteolytic activation and pro-peptide removal will facilitate unfolding of the pre-insertion strands, allowing them to form the β-barrel of the channel.

Turbine component having surface cooling channels and method of forming same

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

Miranda, Carlos Miguel; Trimmer, Andrew Lee; Kottilingam, Srikanth Chandrudu

2017-09-05

A component for a turbine engine includes a substrate that includes a first surface, and an insert coupled to the substrate proximate the substrate first surface. The component also includes a channel. The channel is defined by a first channel wall formed in the substrate and a second channel wall formed by at least one coating disposed on the substrate first surface. The component further includes an inlet opening defined in flow communication with the channel. The inlet opening is defined by a first inlet wall formed in the substrate and a second inlet wall defined by the insert.

Acute promyelocytic leukemia, hypogranular variant, with uncharacteristic staining with chloroacetate esterase.

PubMed

Dunphy, C H; Polski, J M; Johns, G; Evans, H L; Gardner, L J

2001-06-01

A diagnosis of the hypogranular variant of acute promyelocytic leukemia (APLv) may be difficult to establish based on cytomorphology alone. However, the great majority of cases have a classical immunophenotype by flow cytometric immunophenotyping (FCI) (CD13+, CD33+, dim CD64+, HLA-DR-, and CD34-) and a classical enzyme cytochemical (EC) staining pattern. [intensely staining with myeloperoxidase, Sudan Black B, and chloroacetate esterase (CAE) and negative with alpha'-naphthyl acetate and butyrate esterases]. Although the immunophenotype of APLv by FCI has varied in the literature (HLA-DR +/- and CD34 +/-), the EC staining pattern has remained constant. We report a case of APLv with characteristic cytomorphology, compatible FCI data (CD13+, CD33+, dim CD64+, HLA-DR +/-, and CD34-), chromosomal detection of t(15; 17), and molecular detection of the PML/RAR alpha fusion gene; however, staining of the leukemic cells with CAE was quite uncharacteristic. We describe our findings.

Analyzing force concept inventory with item response theory

NASA Astrophysics Data System (ADS)

Wang, Jing; Bao, Lei

2010-10-01

Item response theory is a popular assessment method used in education. It rests on the assumption of a probability framework that relates students' innate ability and their performance on test questions. Item response theory transforms students' raw test scores into a scaled proficiency score, which can be used to compare results obtained with different test questions. The scaled score also addresses the issues of ceiling effects and guessing, which commonly exist in quantitative assessment. We used item response theory to analyze the force concept inventory (FCI). Our results show that item response theory can be useful for analyzing physics concept surveys such as the FCI and produces results about the individual questions and student performance that are beyond the capability of classical statistics. The theory yields detailed measurement parameters regarding the difficulty, discrimination features, and probability of correct guess for each of the FCI questions.

Isometric Arm Strength and Subjective Rating of Upper Limb Fatigue in Two-Handed Carrying Tasks

PubMed Central

Li, Kai Way; Chiu, Wen-Sheng

2015-01-01

Sustained carrying could result in muscular fatigue of the upper limb. Ten male and ten female subjects were recruited for measurements of isometric arm strength before and during carrying a load for a period of 4 minutes. Two levels of load of carrying were tested for each of the male and female subjects. Exponential function based predictive equations for the isometric arm strength were established. The mean absolute deviations of these models in predicting the isometric arm strength were in the range of 3.24 to 17.34 N. Regression analyses between the subjective ratings of upper limb fatigue and force change index (FCI) for the carrying were also performed. The results indicated that the subjective rating of muscular fatigue may be estimated by multiplying the FCI with a constant. The FCI may, therefore, be adopted as an index to assess muscular fatigue for two-handed carrying tasks. PMID:25794159

Isometric arm strength and subjective rating of upper limb fatigue in two-handed carrying tasks.

PubMed

Li, Kai Way; Chiu, Wen-Sheng

2015-01-01

Sustained carrying could result in muscular fatigue of the upper limb. Ten male and ten female subjects were recruited for measurements of isometric arm strength before and during carrying a load for a period of 4 minutes. Two levels of load of carrying were tested for each of the male and female subjects. Exponential function based predictive equations for the isometric arm strength were established. The mean absolute deviations of these models in predicting the isometric arm strength were in the range of 3.24 to 17.34 N. Regression analyses between the subjective ratings of upper limb fatigue and force change index (FCI) for the carrying were also performed. The results indicated that the subjective rating of muscular fatigue may be estimated by multiplying the FCI with a constant. The FCI may, therefore, be adopted as an index to assess muscular fatigue for two-handed carrying tasks.

Measuring Student Effort and Engagement in an Introductory Physics Course

NASA Astrophysics Data System (ADS)

Bonham, Scott

2007-11-01

Multiple scales reflecting student effort were developed using factor and scale analysis on data from an introductory physics course. This data included interactions with an on-line homework system. One of the scales displays many characteristics of a metric of the individual level of engagement in the course. This scale is shown to be a good predictor of performance on class exams and the Force Concept Inventory (FCI). Furthermore, normalized learning gains on the FCI are well predicted by this scale while pre-instructional FCI scores provide no additional predictive ability, agreeing with observations by Richard Hake. This scale also correlates strongly with epistemological beliefs that learning is related to effort and is the responsibility of the student. The factors that enter into this scale, writing and mastering expert-like problem-solving, are consistent with this being a measure of individual levels of class engagement.

British Military freezing cold injuries: a 13-year review.

PubMed

Heil, Kieran M; Oakley, E H N; Wood, A M

2016-12-01

Cold injuries have been a recurrent feature of warfare for millennia and continue to present during British Military operations today. Those affecting the peripheries are divided into freezing cold injury (FCI) and non-FCI. FCI occurs when tissue fluids freeze at around -0.5°C and is commonly referred to as frostnip or frostbite. All FMED7 notes held at the Institute of Naval Medicine's Cold Weather Injury Clinic (CIC) from 2002 to 2014 were searched for the terms 'frostbite' and 'frostnip' and then analysed to identify common themes. In total 245 results were found and from these, 149 patients with a positive FCI diagnosis were identified and formed the cohort of this study. Royal Marines (RM) represented over 50% of patients and Arctic training in Norway accounted for over two thirds of the total cases. The extremities were almost always those areas which were affected by FCI. Further analysis of the RM cases showed the majority of those injured were of the most junior rank (Marine/Private or Lance Corporal). A lack of supporting climatic and activity data meant that it was difficult to draw additional conclusions from the data collected. In future, a greater emphasis should be placed on collection of climatic and additional data when FCIs are diagnosed. These data should be collated at the end of each deployment and published as was regularly done historically. It is hoped that these data could then be used as the starting point for an annual climatic study day, where issues related to FCIs could be discussed in a Tri-Service environment and lessons learned disseminated around all British Forces personnel. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Fabrication of robust tooling for mass production of polymeric microfluidic devices

NASA Astrophysics Data System (ADS)

Fu, G.; Tor, S. B.; Loh, N. H.; Hardt, D. E.

2010-08-01

Polymer microfluidic devices are gaining popularity for bio-applications. In both commonly used methods for the fabrication of polymer microfluidic devices, i.e. injection molding and hot-embossing, the quality of a mold insert is of high importance. Micro powder injection molding (μPIM) provides a suitable option for metal mold insert fabrication. In this paper, two mold inserts with micro-features of different patterns and sizes were produced using 316L stainless steel powder and an in-house binder system. The mold inserts were successfully used to produce cyclic olefin copolymer (COC, trade name TOPAS) micromixer plates with micro-channels of widths 100 µm and 50 µm. Compared with CNC-machined hot work steel mold inserts, the quality of the micro-channels is better as far as geometrical quality and dimensional tolerance are concerned. However, surface finish and flatness of the μPIM mold inserts are inferior to those of CNC-machined mold inserts.

Detecting and Reducing Science Teacher Candidate’s (STC) Misconception About Motion and Force By Using Force Concept Inventory (FCI) and problem Based Learning (PBL)

NASA Astrophysics Data System (ADS)

Oktarisa, Y.; Utami, I. S.; Denny, Y. R.

2017-02-01

This study has been done to 34 science teacher candidates of Teachers’ Training and Education Faculty of Sultan Ageng Tirtayasa University at their first year of study during 2015-2016 school years. This research focused on student’s misconception about motion and force and how Problem Based Learning (PBL) reducing it. Diagnostic test of misconception about motion and force has been detected by using Force Concept Inventory (FCI). FCI had been used in pretest and posttest, and to find the reducing of students’ misconception N-Gain pretest and posttest of each student had been calculated. Quasi experiment one group pretest and posttest had been used as the research method, and Problem Based Learning (PBL) used as the treatment of manipulation. After two weeks learning motion and force with PBL approach, N-gain which obtained prove that misconception about motion and force had been reducing.

Quantum computing applied to calculations of molecular energies: CH2 benchmark.

PubMed

Veis, Libor; Pittner, Jiří

2010-11-21

Quantum computers are appealing for their ability to solve some tasks much faster than their classical counterparts. It was shown in [Aspuru-Guzik et al., Science 309, 1704 (2005)] that they, if available, would be able to perform the full configuration interaction (FCI) energy calculations with a polynomial scaling. This is in contrast to conventional computers where FCI scales exponentially. We have developed a code for simulation of quantum computers and implemented our version of the quantum FCI algorithm. We provide a detailed description of this algorithm and the results of the assessment of its performance on the four lowest lying electronic states of CH(2) molecule. This molecule was chosen as a benchmark, since its two lowest lying (1)A(1) states exhibit a multireference character at the equilibrium geometry. It has been shown that with a suitably chosen initial state of the quantum register, one is able to achieve the probability amplification regime of the iterative phase estimation algorithm even in this case.

Examining gender differences on FCI performance in algebra and calculus based physics courses

NASA Astrophysics Data System (ADS)

Kreutzer, Kimberley; Boudreaux, Andrew

2009-05-01

The Force Concept Inventory (FCI) has been widely used to asses student understanding of Newtonian principles. Studies have shown a marked difference in the performance of men and women on both pre- and post-tests [1,2] and also indicate that experiential based instruction may lead to a reduction in this gender gap [1,3]. This poster presents FCI data collected at Western Washington University. Initial analysis of gender differences are consistent with those reported nationally. We also discuss factors that may contribute to the differences in performance and propose instructional strategies that are designed to address the gender gap. [4pt] [1] M. Lorenzo, et. al., ``Reducing the gender gap in the physics classroom,'' AJP 74(2), 118-122 (2006) [0pt] [2] J. Docktor and K. Heller, ``Gender Differences in Both Force Concept Inventory and Introductory Physics Performance,'' Proceedings at the 2008 PERC [0pt] [3] S. Pollack, et. al., ``Reducing the gender gap in the physics classroom: How sufficient is interactive engagement?'' PRST-PER 3 (2007)

Confirmatory factor analysis applied to the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Eaton, Philip; Willoughby, Shannon D.

2018-06-01

In 1995, Huffman and Heller used exploratory factor analysis to draw into question the factors of the Force Concept Inventory (FCI). Since then several papers have been published examining the factors of the FCI on larger sets of student responses and understandable factors were extracted as a result. However, none of these proposed factor models have been verified to not be unique to their original sample through the use of independent sets of data. This paper seeks to confirm the factor models proposed by Scott et al. in 2012, and Hestenes et al. in 1992, as well as another expert model proposed within this study through the use of confirmatory factor analysis (CFA) and a sample of 20 822 postinstruction student responses to the FCI. Upon application of CFA using the full sample, all three models were found to fit the data with acceptable global fit statistics. However, when CFA was performed using these models on smaller sample sizes the models proposed by Scott et al. and Eaton and Willoughby were found to be far more stable than the model proposed by Hestenes et al. The goodness of fit of these models to the data suggests that the FCI can be scored on factors that are not unique to a single class. These scores could then be used to comment on how instruction methods effect the performance of students along a single factor and more in-depth analyses of curriculum changes may be possible as a result.

Validation of the rheumatic disease comorbidity index.

PubMed

England, Bryant R; Sayles, Harlan; Mikuls, Ted R; Johnson, Dannette S; Michaud, Kaleb

2015-05-01

There is no consensus on which comorbidity index is optimal for rheumatic health outcomes research. We compared a new Rheumatic Disease Comorbidity Index (RDCI) with the Charlson-Deyo Index (CDI), Functional Comorbidity Index (FCI), Elixhauser Total Score (ETS), Elixhauser Point System (EPS), and a simple comorbidity count (COUNT) using a US cohort of rheumatoid arthritis (RA) patients. Using administrative diagnostic codes and patient self-reporting, we tested predictive values of the RDCI, CDI, FCI, ETS, EPS, and COUNT for 2 outcomes: all-cause mortality and physical functioning. Indices were compared using 3 models: bare (consisting of age, sex, and race), administrative (bare plus visit frequency, body mass index, and treatments), and clinic (administrative plus erythrocyte sedimentation rate, nodules, rheumatoid factor positivity, and patient activity scale). The ETS and RDCI best predicted death, with FCI performing the worst. The FCI best predicted function, with ETS and RDCI performing nearly as well. CDI predicted function poorly. The order of indices remained relatively unchanged in the different models, though the magnitude of improvement in Akaike's information criterion decreased in the administrative and clinic models. The RDCI and ETS are excellent indices as a means of accounting for comorbid illness when the RA-related outcomes of death and physical functioning are studied using administrative data. The RDCI is a versatile index and appears to perform well with self-report data as well as administrative data. Further studies are warranted to compare these indices using other outcomes in diverse study populations. © 2015, American College of Rheumatology.

Heat transfer and structure of flow at boiling of refrigerant R134a in channels with inserts in the form of finned twisted tape

NASA Astrophysics Data System (ADS)

Shishkin, A. V.; Tarasevich, S. E.

2018-03-01

The paper presents the results of experimental study of heat transfer for the refrigerant R134a flow in the channels with finned twisted tape inserts at bubble boiling. The flow regimes implemented under the given conditions are shown. The stable cord-like flows appear at boiling in channels with twisted tape inserts and high vapor content when the liquid phase moves in the form of a stream (cord) along the central part of the tape, which is not an active heat exchange surface. At boiling this can lead to an increase in the length required for complete liquid evaporation. Existing geometric modifications of twisted tapes are used in the heat-exchange equipment at forced convection of the coolant and do not solve the problem of cord-like flows elimination. The present work discusses the experimental study of heat transfer at boiling of refrigerant R134a in the channels with twisted tape inserts that have fins on its surface.

Effect of modifying the screw access channels of zirconia implant abutment on the cement flow pattern and retention of zirconia restorations.

PubMed

Wadhwani, Chandur; Chung, Kwok-Hung

2014-07-01

The effect of managing the screw access channels of zirconia implant abutments in the esthetic zone has not been extensively evaluated. The purpose of this study was to determine the effect of an insert placed within the screw access channel of an anterior zirconia implant abutment on the amount of cement retained within the restoration-abutment system and on the dislodging force. Thirty-six paired zirconia abutments and restorations were fabricated by computer-aided design and computer-aided manufacturing and were divided into 3 groups: open abutment, with the screw access channel unfilled; closed abutment, with the screw access channel sealed; and insert abutment, with a thin, tubular metal insert projection continuous with the screw head and placed into the abutment screw access channel. The restorations were cemented to the abutments with preweighed eugenol-free zinc oxide cement (TempBond NE). Excess cement was removed, and the weight of the cement that remained in the restoration-abutment system was measured. Vertical tensile dislodging forces were recorded at a crosshead speed of 5 mm/min after incubation in a 37°C water bath for 24 hours. The specimens were examined for the cement flow pattern into the screw access channel after dislodgement. Data were analyzed with ANOVA, followed by multiple comparisons by using the Tukey honestly significant difference test (α = .05). The mean (standard deviation) of retentive force values ranged from 108.1 ± 29.9 N to 148.3 ± 21.0 N. The retentive force values differed significantly between the insert abutment and both the open abutment (P < .05) and closed abutment groups (P < .01). Distinct patterns of cement failure were noted. The weight of the cement that remained in the system differed significantly, with both open abutment and insert abutment being greater than closed abutment (P < .05). Modifying the internal configuration of the screw access channel of an esthetic zirconia implant abutment with a metal insert significantly affected both the cement retained within the abutment itself and the retention capabilities of the zirconia restoration cemented with TempBond NE cement. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Inductively coupled plasma torch with laminar flow cooling

DOEpatents

Rayson, Gary D.; Shen, Yang

1991-04-30

An improved inductively coupled gas plasma torch. The torch includes inner and outer quartz sleeves and tubular insert snugly fitted between the sleeves. The insert includes outwardly opening longitudinal channels. Gas flowing through the channels of the insert emerges in a laminar flow along the inside surface of the outer sleeve, in the zone of plasma heating. The laminar flow cools the outer sleeve and enables the torch to operate at lower electrical power and gas consumption levels additionally, the laminar flow reduces noise levels in spectroscopic measurements of the gaseous plasma.

Accurate quantum chemical calculations

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

1989-01-01

An important goal of quantum chemical calculations is to provide an understanding of chemical bonding and molecular electronic structure. A second goal, the prediction of energy differences to chemical accuracy, has been much harder to attain. First, the computational resources required to achieve such accuracy are very large, and second, it is not straightforward to demonstrate that an apparently accurate result, in terms of agreement with experiment, does not result from a cancellation of errors. Recent advances in electronic structure methodology, coupled with the power of vector supercomputers, have made it possible to solve a number of electronic structure problems exactly using the full configuration interaction (FCI) method within a subspace of the complete Hilbert space. These exact results can be used to benchmark approximate techniques that are applicable to a wider range of chemical and physical problems. The methodology of many-electron quantum chemistry is reviewed. Methods are considered in detail for performing FCI calculations. The application of FCI methods to several three-electron problems in molecular physics are discussed. A number of benchmark applications of FCI wave functions are described. Atomic basis sets and the development of improved methods for handling very large basis sets are discussed: these are then applied to a number of chemical and spectroscopic problems; to transition metals; and to problems involving potential energy surfaces. Although the experiences described give considerable grounds for optimism about the general ability to perform accurate calculations, there are several problems that have proved less tractable, at least with current computer resources, and these and possible solutions are discussed.

Declining Financial Capacity in Mild Cognitive Impairment: A Six-Year Longitudinal Study.

PubMed

Martin, Roy C; Gerstenecker, Adam; Triebel, Kristen L; Falola, Michael; McPherson, Tarrant; Cutter, Gary; Marson, Daniel C

2018-03-31

To investigate financial skill decline over a 6-year period in persons with mild cognitive impairment (MCI) presumed due to Alzheimer's disease (AD). Study participants were cognitively normal (CN) older adults (n = 82) and adults with MCI (n = 91) based on consensus conference diagnosis. Participants completed baseline and up to six annual follow-up assessments that included standardized financial skills measurement (Financial Capacity Instrument; FCI; nine FCI domain and two global scores). We examined FCI change over time using mixed-model repeated measures analysis adjusted for baseline age and follow-up duration. At baseline, the CN group performed better than the MCI group across both global and seven domain scores. Group × Time interaction effects (all p's <.02) were found for all global and domain scores. The largest interaction effects were observed for complex domains of Financial Conceptual Knowledge, Checkbook Management, Bank Statement Management, and Bill Payment (all p's <.0001). Annualized decline in the MCI group's global scores, calculated in relation to CN group performance, was 10-17% over the initial 3-year time span and 22-24% at 6 years. Decline in FCI domain scores ranged from 6% (Knowledge of Assets/Estate) to 22% (Investment Decision-Making) at 3 year follow-up, and from 15% (Basic Monetary Skills) to 37% (Financial Judgment) at 6 year follow-up. Over a 6-year period, persons with MCI demonstrated significant declines in multiple financial skills and in particular financial judgment. The findings highlight the importance of ongoing oversight by family members and clinicians of financial skills and activities in persons with MCI.

Cluster decomposition of full configuration interaction wave functions: A tool for chemical interpretation of systems with strong correlation

NASA Astrophysics Data System (ADS)

Lehtola, Susi; Tubman, Norm M.; Whaley, K. Birgitta; Head-Gordon, Martin

2017-10-01

Approximate full configuration interaction (FCI) calculations have recently become tractable for systems of unforeseen size, thanks to stochastic and adaptive approximations to the exponentially scaling FCI problem. The result of an FCI calculation is a weighted set of electronic configurations, which can also be expressed in terms of excitations from a reference configuration. The excitation amplitudes contain information on the complexity of the electronic wave function, but this information is contaminated by contributions from disconnected excitations, i.e., those excitations that are just products of independent lower-level excitations. The unwanted contributions can be removed via a cluster decomposition procedure, making it possible to examine the importance of connected excitations in complicated multireference molecules which are outside the reach of conventional algorithms. We present an implementation of the cluster decomposition analysis and apply it to both true FCI wave functions, as well as wave functions generated from the adaptive sampling CI algorithm. The cluster decomposition is useful for interpreting calculations in chemical studies, as a diagnostic for the convergence of various excitation manifolds, as well as as a guidepost for polynomially scaling electronic structure models. Applications are presented for (i) the double dissociation of water, (ii) the carbon dimer, (iii) the π space of polyacenes, and (iv) the chromium dimer. While the cluster amplitudes exhibit rapid decay with an increasing rank for the first three systems, even connected octuple excitations still appear important in Cr2, suggesting that spin-restricted single-reference coupled-cluster approaches may not be tractable for some problems in transition metal chemistry.

Applying the Socratic Method to Physics Education

NASA Astrophysics Data System (ADS)

Corcoran, Ed

2005-04-01

We have restructured University Physics I and II in accordance with methods that PER has shown to be effective, including a more interactive discussion- and activity-based curriculum based on the premise that developing understanding requires an interactive process in which students have the opportunity to talk through and think through ideas with both other students and the teacher. Studies have shown that in classes implementing this approach to teaching as compared to classes using a traditional approach, students have significantly higher gains on the Force Concept Inventory (FCI). This has been true in UPI. However, UPI FCI results seem to suggest that there is a significant conceptual hole in students' understanding of Newton's Second Law. Two labs in UPI which teach Newton's Second Law will be redesigned replacing more activity with students as a group talking through, thinking through, and answering conceptual questions asked by the TA. The results will be measured by comparing FCI results to those from previous semesters, coupled with interviews. The results will be analyzed, and we will attempt to understand why gains were or were not made.

[Resistivity and hemodynamic reactions of essentially healthy pilots to the passive orthostatic test].

PubMed

Bondareva, S V; Vartbaronov, R A; Ponomarenko, K V; Bagaudinov, K G; Khomenko, M N

2009-01-01

The paper analyzes the data of expert tilt testing (-80 degrees, 20 min.) of 66 essentially healthy pilots. Hemodynamic reactions were characterized based on the standard concept of functional classes (FC). Good test tolerance was recorded in 86.4% of cases among which 36.4% were referred to FC-I and 50%--to FC-II. Adequate test tolerance (FC-II) was recorded in 10.6%; reduced and poor test tolerance (FC-IV and FC-V)--in 3%. According to ECG and computerized tachooscillography, the adaptive hemodynamic reactions were optimum in pilots of group FC-I as compared with group FC-II and all the more so when compared with FC-III. The last two groups showed some objective symptoms that had not been looked for in the past (a distinct lability of blood pressure, and incomplete hypertensive and hypotensive reactions) that differentiated these groups from FC-I. Results of the analysis made it possible to put forward additional clinical functional criteria to assess tilt tolerance of pilots with different levels of functional tolerance.

Time-multiplexed two-channel capacitive radiofrequency hyperthermia with nanoparticle mediation.

PubMed

Kim, Ki Soo; Hernandez, Daniel; Lee, Soo Yeol

2015-10-24

Capacitive radiofrequency (RF) hyperthermia suffers from excessive temperature rise near the electrodes and poorly localized heat transfer to the deep-seated tumor region even though it is known to have potential to cure ill-conditioned tumors. To better localize heat transfer to the deep-seated target region in which electrical conductivity is elevated by nanoparticle mediation, two-channel capacitive RF heating has been tried on a phantom. We made a tissue-mimicking phantom consisting of two compartments, a tumor-tissue-mimicking insert against uniform background agarose. The tumor-tissue-mimicking insert was made to have higher electrical conductivity than the normal-tissue-mimicking background by applying magnetic nanoparticle suspension to the insert. Two electrode pairs were attached on the phantom surface by equal-angle separation to apply RF electric field to the phantom. To better localize heat transfer to the tumor-tissue-mimicking insert, RF power with a frequency of 26 MHz was delivered to the two channels in a time-multiplexed way. To monitor the temperature rise inside the phantom, MR thermometry was performed at a 3T MRI intermittently during the RF heating. Finite-difference-time-domain (FDTD) electromagnetic and thermal simulations on the phantom model were also performed to verify the experimental results. As compared to the one-channel RF heating, the two-channel RF heating with time-multiplexed driving improved the spatial localization of heat transfer to the tumor-tissue-mimicking region in both the simulation and experiment. The two-channel RF heating also reduced the temperature rise near the electrodes significantly. Time-multiplexed two-channel capacitive RF heating has the capability to better localize heat transfer to the nanoparticle-mediated tumor region which has higher electrical conductivity than the background normal tissues.

Gas turbine row #1 steam cooled vane

DOEpatents

Cunha, Frank J.

2000-01-01

A design for a vane segment having a closed-loop steam cooling system is provided. The vane segment comprises an outer shroud, an inner shroud and an airfoil, each component having a target surface on the inside surface of its walls. A plurality of rectangular waffle structures are provided on the target surface to enhance heat transfer between each component and cooling steam. Channel systems are provided in the shrouds to improve the flow of steam through the shrouds. Insert legs located in cavities in the airfoil are also provided. Each insert leg comprises outer channels located on a perimeter of the leg, each outer channel having an outer wall and impingement holes on the outer wall for producing impingement jets of cooling steam to contact the airfoil's target surface. Each insert leg further comprises a plurality of substantially rectangular-shaped ribs located on the outer wall and a plurality of openings located between outer channels of the leg to minimize cross flow degradation.

Age and education corrected older adult normative data for a short form version of the Financial Capacity Instrument.

PubMed

Gerstenecker, Adam; Eakin, Amanda; Triebel, Kristen; Martin, Roy; Swenson-Dravis, Dana; Petersen, Ronald C; Marson, Daniel

2016-06-01

Financial capacity is an instrumental activity of daily living (IADL) that comprises multiple abilities and is critical to independence and autonomy in older adults. Because of its cognitive complexity, financial capacity is often the first IADL to show decline in prodromal and clinical Alzheimer's disease and related disorders. Despite its importance, few standardized assessment measures of financial capacity exist and there is little, if any, normative data available to evaluate financial skills in the elderly. The Financial Capacity Instrument-Short Form (FCI-SF) is a brief measure of financial skills designed to evaluate financial skills in older adults with cognitive impairment. In the current study, we present age- and education-adjusted normative data for FCI-SF variables in a sample of 1344 cognitively normal, community-dwelling older adults participating in the Mayo Clinic Study of Aging (MCSA) in Olmsted County, Minnesota. Individual FCI-SF raw scores were first converted to age-corrected scaled scores based on position within a cumulative frequency distribution and then grouped within 4 empirically supported and overlapping age ranges. These age-corrected scaled scores were then converted to age- and education-corrected scaled scores using the same methodology. This study has the potential to substantially enhance financial capacity evaluations of older adults through the introduction of age- and education-corrected normative data for the FCI-SF by allowing clinicians to: (a) compare an individual's performance to that of a sample of similar age and education peers, (b) interpret various aspects of financial capacity relative to a normative sample, and (c) make comparisons between these aspects. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

The H2 + + He proton transfer reaction: quantum reactive differential cross sections to be linked with future velocity mapping experiments

NASA Astrophysics Data System (ADS)

Hernández Vera, Mario; Wester, Roland; Gianturco, Francesco Antonio

2018-01-01

We construct the velocity map images of the proton transfer reaction between helium and molecular hydrogen ion {{{H}}}2+. We perform simulations of imaging experiments at one representative total collision energy taking into account the inherent aberrations of the velocity mapping in order to explore the feasibility of direct comparisons between theory and future experiments planned in our laboratory. The asymptotic angular distributions of the fragments in a 3D velocity space is determined from the quantum state-to-state differential reactive cross sections and reaction probabilities which are computed by using the time-independent coupled channel hyperspherical coordinate method. The calculations employ an earlier ab initio potential energy surface computed at the FCI/cc-pVQZ level of theory. The present simulations indicate that the planned experiments would be selective enough to differentiate between product distributions resulting from different initial internal states of the reactants.

Can dual processing theory explain physics students' performance on the Force Concept Inventory?

NASA Astrophysics Data System (ADS)

Wood, Anna K.; Galloway, Ross K.; Hardy, Judy

2016-12-01

According to dual processing theory there are two types, or modes, of thinking: system 1, which involves intuitive and nonreflective thinking, and system 2, which is more deliberate and requires conscious effort and thought. The Cognitive Reflection Test (CRT) is a widely used and robust three item instrument that measures the tendency to override system 1 thinking and to engage in reflective, system 2 thinking. Each item on the CRT has an intuitive (but wrong) answer that must be rejected in order to answer the item correctly. We therefore hypothesized that performance on the CRT may give useful insights into the cognitive processes involved in learning physics, where success involves rejecting the common, intuitive ideas about the world (often called misconceptions) and instead carefully applying physical concepts. This paper presents initial results from an ongoing study examining the relationship between students' CRT scores and their performance on the Force Concept Inventory (FCI), which tests students' understanding of Newtonian mechanics. We find that a higher CRT score predicts a higher FCI score for both precourse and postcourse tests. However, we also find that the FCI normalized gain is independent of CRT score. The implications of these results are discussed.

The mechanistic basis of pH-dependent 5-flucytosine resistance in Aspergillus fumigatus.

PubMed

Gsaller, Fabio; Furukawa, Takanori; Carr, Paul D; Rash, Bharat; Jöchl, Christoph; Bertuzzi, Margherita; Bignell, Elaine M; Bromley, Michael J

2018-04-02

The antifungal drug 5-flucytosine (5FC), a derivative of the nucleobase cytosine, is licenced for treatment of fungal diseases however it is rarely used as a monotherapeutic to treat Aspergillus infection. Despite being potent against other fungal pathogens, 5FC has limited activity against A. fumigatus when standard in vitro assays are used to determine susceptibility. However, in modified in vitro assays where the pH is set to pH 5 the activity of 5FC increases significantly.Here we provide evidence that fcyB , a gene that encodes a purine-cytosine permease orthologous to known 5FC importers is downregulated at pH 7 and is the primary factor responsible for the low efficacy of 5FC at pH 7. We also uncover two transcriptional regulators that are responsible for repression of fcyB and consequently mediators of 5FC resistance, the CCAAT binding complex (CBC) and the pH regulatory protein PacC. We propose that the activity of 5FC might be enhanced by perturbation of factors that repress fcyB expression such as PacC or other components of the pH sensing machinery. Copyright © 2018 American Society for Microbiology.

A Study of Impairing Injuries in Real World Crashes Using the Injury Impairment Scale (IIS) and the Predicted Functional Capacity Index (PFCI-AIS)

PubMed Central

Barnes, Jo; Morris, Andrew

2009-01-01

The ability to predict impairment outcomes in large databases using a simplified technique allows researchers to focus attention on preventing costly impairing injuries. The dilemma that exists for researchers is to determine which method is the most reliable and valid. This study examines available methods to predict impairment and explores the differences between the IIS and pFCI applied to real world crash injury data. Occupant injury data from the UK Co-operative Crash Injury Study (CCIS) database have been coded using AIS 1990 and AIS 2005. The data have subsequently been recoded using the associated impairment scales namely the Injury Impairment Scale (IIS) and the predicted Functional Capacity Index (pFCI) to determine the predicted impairment levels of injuries at one year post crash. Comparisons between the levels of impairment were made and any differences further explored. Injury data for the period February 2006 to September 2008 from the CCIS database were used in the analysis which involved a dataset of 2,437 occcupants who sustained over 8000 injuries. This study found some differences between the impairment scales for injuries coded to the AIS 1990 and AIS 2005 coding dictionaries. The pFCI predicts 31.5% of injuries to be impairing in AIS 2005, less than the IIS (38.5%) using AIS 1990. Using CCIS data the pFCI predicted that only 6% of the occupants with a coded injury would have an impairing injury compared to 24% of occupants using the IIS. The main body regions identified as having the major differences between the two impairment scales for car occupants were the head and spine. Follow up data were then used for a small number of cases (n=31, lower extremity and whiplash injuries) to examine any differences in predicted impairment versus perceived impairment. These data were selected from a previous study conducted between 2003 and 2006 and identified the discrepancy between predicted impairment and actual perceived impairment as defined by the participant. Overall the work highlights the variaton between the pFCI and IIS and emphasises the importance and need for a single validated impairment scale that can be universally applied. This would allow emphasis to be directed towards preventing injuries that are associated with the most significant impairment outcomes. PMID:20184844

A study of impairing injuries in real world crashes using the Injury Impairment Scale (IIS) and the predicted Functional Capacity Index (PFCI-AIS).

PubMed

Barnes, Jo; Morris, Andrew

2009-10-01

The ability to predict impairment outcomes in large databases using a simplified technique allows researchers to focus attention on preventing costly impairing injuries. The dilemma that exists for researchers is to determine which method is the most reliable and valid. This study examines available methods to predict impairment and explores the differences between the IIS and pFCI applied to real world crash injury data. Occupant injury data from the UK Co-operative Crash Injury Study (CCIS) database have been coded using AIS 1990 and AIS 2005. The data have subsequently been recoded using the associated impairment scales namely the Injury Impairment Scale (IIS) and the predicted Functional Capacity Index (pFCI) to determine the predicted impairment levels of injuries at one year post crash. Comparisons between the levels of impairment were made and any differences further explored. Injury data for the period February 2006 to September 2008 from the CCIS database were used in the analysis which involved a dataset of 2,437 occcupants who sustained over 8000 injuries. This study found some differences between the impairment scales for injuries coded to the AIS 1990 and AIS 2005 coding dictionaries. The pFCI predicts 31.5% of injuries to be impairing in AIS 2005, less than the IIS (38.5%) using AIS 1990. Using CCIS data the pFCI predicted that only 6% of the occupants with a coded injury would have an impairing injury compared to 24% of occupants using the IIS. The main body regions identified as having the major differences between the two impairment scales for car occupants were the head and spine. Follow up data were then used for a small number of cases (n=31, lower extremity and whiplash injuries) to examine any differences in predicted impairment versus perceived impairment. These data were selected from a previous study conducted between 2003 and 2006 and identified the discrepancy between predicted impairment and actual perceived impairment as defined by the participant. Overall the work highlights the variation between the pFCI and IIS and emphasises the importance and need for a single validated impairment scale that can be universally applied. This would allow emphasis to be directed towards preventing injuries that are associated with the most significant impairment outcomes.

Channel nut tool

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

Olson, Marvin

A method, system, and apparatus for installing channel nuts includes a shank, a handle formed on a first end of a shank, and an end piece with a threaded shaft configured to receive a channel nut formed on the second end of the shaft. The tool can be used to insert or remove a channel nut in a channel framing system and then removed from the channel nut.

Voltage-driven reversible insertion into and leaving from a lipid bilayer: tuning transmembrane transport of artificial channels.

PubMed

Si, Wen; Li, Zhan-Ting; Hou, Jun-Li

2014-04-25

Three new artificial transmembrane channel molecules have been designed and synthesized by attaching positively charged Arg-incorporated tripeptide chains to pillar[5]arene. Fluorescent and patch-clamp experiments revealed that voltage can drive the molecules to insert into and leave from a lipid bilayer and thus switch on and off the transport of K(+) ions. One of the molecules was found to display antimicrobial activity toward Bacillus subtilis with half maximal inhibitory concentration (IC50 ) of 10 μM which is comparable to that of natural channel-forming peptide alamethicin. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interrogation cradle and insertable containment fixture for detecting birefringent microcrystals in bile

DOEpatents

Darrow, Chris; Seger, Tino

2003-09-30

A transparent flow channel fluidly communicates a fluid source and a collection reservoir. An interrogating light beam passes through a first polarizer having a first plane of polarization. The flow channel is orthogonal to the light beam. The light beam passes through a fluid sample as it flows through the flow channel, and is then filtered through a second polarizer having a second plane of polarization rotated 90.degree. from the first plane of polarization. An electronic photo-detector is aligned with the light beam, and signals the presence of birefringent microcrystals in the fluid sample by generating voltage pulses. A disposable containment fixture includes the flow channel and the collection reservoir. The fixture is adapted for removable insertion into an interrogation cradle that includes optical and data processing components. The cradle rigidly positions the centerline of the flow channel orthogonal to the light beam.

Theoretical study of the hyperfine parameters of OH

NASA Technical Reports Server (NTRS)

Chong, Delano P.; Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.

1991-01-01

In the present study of the hyperfine parameters of O-17H as a function of the one- and n-particle spaces, all of the parameters except oxygen's spin density, b sub F(O), are sufficiently easily tractable to allow concentration on the computational requirements for accurate determination of b sub F(O). Full configuration-interaction (FCI) calculations in six Gaussian basis sets yield unambiguous results for (1) the effect of uncontracting the O s and p basis sets; (2) that of adding diffuse s and p functions; and (3) that of adding polarization functions to O. The size-extensive modified coupled-pair functional method yields b sub F values which are in fair agreement with FCI results.

LETTERS AND COMMENTS: Comment on 'The effects of students' reasoning abilities on conceptual understanding and problem-solving skills in introductory mechanics'

NASA Astrophysics Data System (ADS)

Coletta, Vincent P.; Phillips, Jeffrey A.; Savinainen, Antti; Steinert, Jeffrey J.

2008-09-01

In a recent article, Ates and Cataloglu (2007 Eur. J. Phys. 28 1161-71), in analysing results for a course in introductory mechanics for prospective science teachers, found no statistically significant correlation between students' pre-instruction scores on the Lawson classroom test of scientific reasoning ability (CTSR) and post-instruction scores on the force concept inventory (FCI). As a possible explanation, the authors suggest that the FCI does not probe for skills required to determine reasoning abilities. Our previously published research directly contradicts the authors' finding. We summarize our research and present a likely explanation for their observation of no correlation.

Essential role of the unordered VP2 n-terminal domain of the parvovirus MVM capsid in nuclear assembly and endosomal enlargement of the virion fivefold channel for cell entry

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

Sanchez-Martinez, Cristina; Grueso, Esther; Carroll, Miles

The unordered N-termini of parvovirus capsid proteins (Nt) are translocated through a channel at the icosahedral five-fold axis to serve for virus traffick. Heterologous peptides were genetically inserted at the Nt of MVM to study their functional tolerance to manipulations. Insertion of a 5T4-single-chain antibody at VP2-Nt (2Nt) yielded chimeric capsid subunits failing to enter the nucleus. The VEGFR2-binding peptide (V1) inserted at both 2Nt and VP1-Nt efficiently assembled in virions, but V1 disrupted VP1 and VP2 entry functions. The VP2 defect correlated with restricted externalization of V1-2Nt out of the coat. The specific infectivity of MVM and wtVP-pseudotyped mosaicmore » MVM-V1 virions, upon heating and/or partial 2Nt cleavage, demonstrated that some 2Nt domains become intracellularly translocated out of the virus shell and cleaved to initiate entry. The V1 insertion defines a VP2-driven endosomal enlargement of the channel as an essential structural rearrangement performed by the MVM virion to infect.« less

Fetal Intervention in Right Outflow Tract Obstructive Disease: Selection of Candidates and Results

PubMed Central

Gómez Montes, E.; Herraiz, I.; Mendoza, A.; Galindo, A.

2012-01-01

Objectives. To describe the process of selection of candidates for fetal cardiac intervention (FCI) in fetuses diagnosed with pulmonary atresia-critical stenosis with intact ventricular septum (PA/CS-IVS) and report our own experience with FCI for such disease. Methods. We searched our database for cases of PA/CS-IVS prenatally diagnosed in 2003–2012. Data of 38 fetuses were retrieved and analyzed. FCI were offered to 6 patients (2 refused). In the remaining it was not offered due to the presence of either favourable prognostic echocardiographic markers (n = 20) or poor prognostic indicators (n = 12). Results. The outcome of fetuses with PA/CS-IVS was accurately predicted with multiparametric scoring systems. Pulmonary valvuloplasty was technically successful in all 4 fetuses. The growth of the fetal right heart and hemodynamic parameters showed a Gaussian-like behaviour with an improvement in the first weeks and slow worsening as pregnancy advanced, probably indicating a restenosis. Conclusions. The most likely type of circulation after birth may be predicted in the second trimester of pregnancy by means of combining cardiac dimensions and functional parameters. Fetal pulmonary valvuloplasty in midgestation is technically feasible and in well-selected cases may improve right heart growth, fetal hemodynamics, and postnatal outcome. PMID:22928144

Cognitive correlates of financial abilities in mild cognitive impairment.

PubMed

Okonkwo, Ozioma C; Wadley, Virginia G; Griffith, H Randall; Ball, Karlene; Marson, Daniel C

2006-11-01

To investigate the cognitive correlates of financial abilities in mild cognitive impairment (MCI). Controlled, matched-sample, cross-sectional analysis regressing five cognitive composites on financial performance measures. University medical and research centers. Forty-three persons with MCI and 43 normal controls. The Financial Capacity Instrument (FCI) and a comprehensive neurocognitive battery. Patients with MCI performed significantly worse than controls on cognitive domains of executive function, memory, and language and on FCI domains of financial conceptual knowledge, bank statement management, and bill payment. Patients with MCI also needed significantly more time to complete a multistep financial task and were significantly more likely than controls to make errors on this task. Stepwise regression models revealed that, within the MCI group, attention and executive function were significant correlates of FCI performance. Although impaired memory is the cardinal deficit in MCI, the neurocognitive basis of lower functional performance in MCI appears to be emergent declines in abilities to selectively attend, self-monitor, and temporally integrate information. Compromised performance on cognitive measures of attention and executive function may constitute clinical markers of lower financial abilities and should be evaluated for its relationship to functional ability in general. These cognitive domains may be appropriate targets of future intervention studies aimed at preservation of functional independence in people with MCI.

Experimental studies of thermal and chemical interactions between oxide and silicide nuclear fuels with water

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

farahani, A.A.; Corradini, M.L.

Given some transient power/cooling mismatch is a nuclear reactor and its inability to establish the necessary core cooling, energetic fuel-coolant interactions (FCI`s commonly called `vapor explosions`) could occur as a result of the core melting and coolant contact. Although a large number of studies have been done on energetic FCI`s, very few experiments have been performed with the actual fuel materials postulated to be produced in severe accidents. Because of the scarcity of well-characterized FCI data for uranium allows in noncommercial reactors (cermet and silicide fuels), we have conducted a series of experiments to provide a data base for themore » foregoing materials. An existing 1-D shock-tube facility was modified to handle depleted radioactive materials (U{sub 3}O{sub 8}-Al, and U{sub 3}Si{sub 2}-Al). Our objectives have been to determine the effects of the initial fuel composition and temperature and the driving pressure (triggering) on the explosion work output, dynamic pressures, transient temperatures, and the hydrogen production. Experimental results indicate limited energetics, mainly thermal interactions, for these fuel materials as compared to aluminum where more chemical reactions occur between the molten aluminum and water.« less

Dirichlet boundary conditions for arbitrary-shaped boundaries in stellarator-like magnetic fields for the Flux-Coordinate Independent method

NASA Astrophysics Data System (ADS)

Hill, Peter; Shanahan, Brendan; Dudson, Ben

2017-04-01

We present a technique for handling Dirichlet boundary conditions with the Flux Coordinate Independent (FCI) parallel derivative operator with arbitrary-shaped material geometry in general 3D magnetic fields. The FCI method constructs a finite difference scheme for ∇∥ by following field lines between poloidal planes and interpolating within planes. Doing so removes the need for field-aligned coordinate systems that suffer from singularities in the metric tensor at null points in the magnetic field (or equivalently, when q → ∞). One cost of this method is that as the field lines are not on the mesh, they may leave the domain at any point between neighbouring planes, complicating the application of boundary conditions. The Leg Value Fill (LVF) boundary condition scheme presented here involves an extrapolation/interpolation of the boundary value onto the field line end point. The usual finite difference scheme can then be used unmodified. We implement the LVF scheme in BOUT++ and use the Method of Manufactured Solutions to verify the implementation in a rectangular domain, and show that it does not modify the error scaling of the finite difference scheme. The use of LVF for arbitrary wall geometry is outlined. We also demonstrate the feasibility of using the FCI approach in no n-axisymmetric configurations for a simple diffusion model in a "straight stellarator" magnetic field. A Gaussian blob diffuses along the field lines, tracing out flux surfaces. Dirichlet boundary conditions impose a last closed flux surface (LCFS) that confines the density. Including a poloidal limiter moves the LCFS to a smaller radius. The expected scaling of the numerical perpendicular diffusion, which is a consequence of the FCI method, in stellarator-like geometry is recovered. A novel technique for increasing the parallel resolution during post-processing, in order to reduce artefacts in visualisations, is described.

Dual-energy-X-ray imaging to measure phase volume fractions in a transient multiphase flow

NASA Astrophysics Data System (ADS)

Loewen, Eric Paul

1999-12-01

The objective of this research was to visualize the pre-mixing phase of a fuel-coolant interaction (FCI) by using combinations of high-speed cinematography and dual energy X-ray imaging to identify and quantify the spatial and temporal characteristics of the three FCI phases---metal (fuel), liquid (coolant water), and voids (generated steam). (1) The high-speed cinematography imaging subsystem and the low-energy X-ray imaging subsystem provided visual photographs and distinguished generated voids from water. (2) The high-energy X-Ray imaging subsystem provided additional discernment of metal from water and vapor. This is the first time that dynamic dual X-ray images have been provided with quantitative results. The data provide new information concerning the melt fractions, melt jet configuration, melt jet velocity, and qualitative spatial and temporal quantification of the pre-mixing event. This information provides new insight into the FCI phenomenon that could not have been deduced from visible-light imaging or other instrumentation such as thermocouples, void sensors, or pressure transmitters. Significant findings include: (1) the fuel column (molten Pb jet) penetrated deeply (<7 cm) into the coolant (water) while maintaining its columnar shape. (2) Energetic FCIs occurred (and were imaged) below the melt-coolant interface temperature equal to the homogenous nucleation temperature (310°C). (3) The molten jet breakup was observed to be caused by hydrodynamic forces. (4) The Pb/water thermal interaction zone was imaged over melt temperatures from 330°C to 640°C and coolant subcooling of 4°C to 80°C. (5) The interface regions between the molten Pb and coolant was observed to grow with decreasing coolant subcooling. This imaging process can be applied to further study of the FCI phenomena at other test facilities. It can also be applied for observation of other two- or three-phase flow phenomena previously opaque to conventional imaging systems.

Deriving common comorbidity indices from the MedDRA classification and exploring their performance on key outcomes in patients with rheumatoid arthritis.

PubMed

Putrik, Polina; Ramiro, Sofia; Lie, Elisabeth; Michaud, Kaleb; Kvamme, Maria K; Keszei, Andras P; Kvien, Tore K; Uhlig, Till; Boonen, Annelies

2018-03-01

To develop algorithms for calculating the Rheumatic Diseases Comorbidity Index (RDCI), Charlson-Deyo Index (CDI) and Functional Comorbidity Index (FCI) from the Medical Dictionary for Regulatory Activities (MedDRA), and to assess how these MedDRA-derived indices predict clinical outcomes, utility and health resource utilization (HRU). Two independent researchers linked the preferred terms of the MedDRA classification into the conditions included in the RDCI, the CDI and the FCI. Next, using data from the Norwegian Register-DMARD study (a register of patients with inflammatory joint diseases treated with DMARDs), the explanatory value of these indices was studied in models adjusted for age, gender and DAS28. Model fit statistics were compared in generalized estimating equation (prediction of outcome over time) models using as outcomes: modified HAQ, HAQ, physical and mental component summary of SF-36, SF6D and non-RA related HRU. Among 4126 patients with RA [72% female, mean (s.d.) age 56 (14) years], median (interquartile range) of RDCI at baseline was 0.0 (1.0) [range 0-6], CDI 0.0 (0.0) [0-7] and FCI 0.0 (1.0) [0-6]. All the comorbidity indices were associated with each outcome, and differences in their performance were moderate. The RDCI and FCI performed better on clinical outcomes: modified HAQ and HAQ, hospitalization, physical and mental component summary, and SF6D. Any non-RA related HRU was best predicted by RDCI followed by CDI. An algorithm is now available to compute three commonly used comorbidity indices from MedDRA classification. Indices performed comparably well in predicting a variety of outcomes, with the CDI performing slightly worse when predicting outcomes reflecting functioning and health. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Laser beam guard clamps

DOEpatents

Dickson, Richard K.

2010-09-07

A quick insert and release laser beam guard panel clamping apparatus having a base plate mountable on an optical table, a first jaw affixed to the base plate, and a spring-loaded second jaw slidably carried by the base plate to exert a clamping force. The first and second jaws each having a face acutely angled relative to the other face to form a V-shaped, open channel mouth, which enables wedge-action jaw separation by and subsequent clamping of a laser beam guard panel inserted through the open channel mouth. Preferably, the clamping apparatus also includes a support structure having an open slot aperture which is positioned over and parallel with the open channel mouth.

Miniature ureteroscope tip designs for use in thulium fiber laser lithotripsy

NASA Astrophysics Data System (ADS)

Kennedy, Joshua D.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

2017-02-01

A miniature ureteroscope has the potential to eliminate need for full anesthesia and dilation, increase comfort and safety of laser lithotripsy via ureteroscopy, and reduce hospital costs via an office based procedure. A prototype, 4.5 Fr (1.5-mm-OD), five channel ureteroscope tip was developed, housing a 200-μm-ID central channel for insertion of small, 100-μm-core fibers and four surrounding channels, each with 510-μm-ID for instrumentation, irrigation, imaging, and illumination, respectively. Common urological instruments (including fibers, guidewires, and stone baskets) were inserted through tip's working channels to demonstrate feasibility. Low irrigation rates were measured, revealing a need for manual pump-assisted irrigation. Imaging was conducted using 3k, 6k, and 10k pixel miniature flexible endoscopes with 0.4, 0.6, and 0.9 mm outer diameters, respectively. The 3k pixel endoscope with integrated illumination was inserted through the prototype unimpeded, and successfully demonstrated ability to differentiate between hard tissues (e.g. kidney stones) and soft tissues (e.g. ureter wall), for visibility and safety during potential clinical application. Based on both image quality and instrument diameter, the 6k pixel endoscope provided an optimal solution for miniature ureteroscopy.

Secondary analysis of teaching methods in introductory physics: A 50 k-student study

NASA Astrophysics Data System (ADS)

Von Korff, Joshua; Archibeque, Benjamin; Gomez, K. Alison; Heckendorf, Tyrel; McKagan, Sarah B.; Sayre, Eleanor C.; Schenk, Edward W.; Shepherd, Chase; Sorell, Lane

2016-12-01

Physics education researchers have developed many evidence-based instructional strategies to enhance conceptual learning of students in introductory physics courses. These strategies have historically been tested using assessments such as the Force Concept Inventory (FCI) and the Force and Motion Conceptual Evaluation (FMCE). We have performed a review and analysis of FCI and FMCE data published between 1995 and 2014. We confirm previous findings that interactive engagement teaching techniques are significantly more likely to produce high student learning gains than traditional lecture-based instruction. We also establish that interactive engagement instruction works in many settings, including those with students having a high and low level of prior knowledge, at liberal arts and research universities, and enrolled in both small and large classes.

Cooling system for a gas turbine using a cylindrical insert having V-shaped notch weirs

DOEpatents

Grondahl, Clayton M.; Germain, Malcolm R.

1981-01-01

An improved cooling system for a gas turbine is disclosed. A plurality of V-shaped notch weirs are utilized to meter a coolant liquid from a pool of coolant into a plurality of platform and airfoil coolant channels formed in the buckets of the turbine. The V-shaped notch weirs are formed in a separately machined cylindrical insert and serve to desensitize the flow of coolant into the individual platform and airfoil coolant channels to design tolerances and non-uniform flow distribution.

Essential role of the unordered VP2 n-terminal domain of the parvovirus MVM capsid in nuclear assembly and endosomal enlargement of the virion fivefold channel for cell entry.

PubMed

Sánchez-Martínez, Cristina; Grueso, Esther; Carroll, Miles; Rommelaere, Jean; Almendral, José M

2012-10-10

The unordered N-termini of parvovirus capsid proteins (Nt) are translocated through a channel at the icosahedral five-fold axis to serve for virus traffick. Heterologous peptides were genetically inserted at the Nt of MVM to study their functional tolerance to manipulations. Insertion of a 5T4-single-chain antibody at VP2-Nt (2Nt) yielded chimeric capsid subunits failing to enter the nucleus. The VEGFR2-binding peptide (V1) inserted at both 2Nt and VP1-Nt efficiently assembled in virions, but V1 disrupted VP1 and VP2 entry functions. The VP2 defect correlated with restricted externalization of V1-2Nt out of the coat. The specific infectivity of MVM and wtVP-pseudotyped mosaic MVM-V1 virions, upon heating and/or partial 2Nt cleavage, demonstrated that some 2Nt domains become intracellularly translocated out of the virus shell and cleaved to initiate entry. The V1 insertion defines a VP2-driven endosomal enlargement of the channel as an essential structural rearrangement performed by the MVM virion to infect. Copyright © 2012 Elsevier Inc. All rights reserved.

The sorting of a small potassium channel in mammalian cells can be shifted between mitochondria and plasma membrane.

PubMed

von Charpuis, Charlotte; Meckel, Tobias; Moroni, Anna; Thiel, Gerhard

2015-07-01

The two small and similar viral K(+) channels Kcv and Kesv are sorted in mammalian cells and yeast to different destinations. Analysis of the sorting pathways shows that Kcv is trafficking via the secretory pathway to the plasma membrane, while Kesv is inserted via the TIM/TOM complex to the inner membrane of mitochondria. Studies with Kesv mutants show that an N-terminal mitochondrial targeting sequence in this channel is neither necessary nor sufficient for sorting of Kesv the mitochondria. Instead the sorting of Kesv can be redirected from the mitochondria to the plasma membrane by an insertion of ≥2 amino acids in a position sensitive manner into the C-terminal transmembrane domain (TMD2) of this channel. The available data advocate the presence of a C-terminal sorting signal in TMD2 of Kesv channel, which is presumably not determined by the length of this domain. Copyright © 2014. Published by Elsevier Ltd.

Biochemical non-invasive assessment of liver fibrosis cannot replace biopsy in HIV-HCV coinfected patients.

PubMed

Kliemann, Dimas A; Wolff, Fernando H; Tovo, Cristiane V; Alencastro, Paulo R; Ikeda, Maria L R; Brandão, Ajácio B M; Barcellos, Nêmora; Fuchs, Sandra C

2016-01-01

The liver biopsy has been considered the gold standard for the diagnosis and quantification of fibrosis. However, this method presents limitations. In addition, the non-invasive evaluation of liver fibrosis is a challenge. The aim of this study was to validate the fibrosis cirrhosis index (FCI) index in a cohort of human immunodeficiency virus (HIV)/hepatitis C virus (HCV) coinfected patients, and compare to AST/ALT ratio (AAR), AST to platelet ratio index (APRI) and FIB-4 scores, as a tool for the assessment of liver fibrosis in coinfected patients. Retrospective cross sectional study including 92 HIV-HCV coinfected patients evaluated in two reference centers for HIV treatment in the Public Health System in Southern Brazil. Patients who underwent liver biopsy for any indication and had concomitant laboratory data in the 3 months prior to liver biopsy, to allow the calculation of studied noninvasive markers (AAR, APRI, FIB-4 and FCI) were included. APRI < 0.5 presents the higher specificity to detect no or minimal fibrosis, whereas APRI > 1.5 presents the best negative predictive value and FCI > 1.25 the best specificity to detect significant fibrosis. The values of noninvasive markers for each Metavir fibrosis stage showed statistically significant differences only for APRI. In conclusion, until better noninvasive markers for liver fibrosis are developed and validated for HIV-HCV coinfected patients, noninvasive serum markers should be used carefully in this population.

Implications of Functional Capacity Loss and Fatality for Vehicle Safety Prioritization.

PubMed

McMurry, Timothy L; Sherwood, Chris; Poplin, Gerald S; Seguí-Gómez, María; Crandall, Jeff

2015-01-01

We investigate the use of the Functional Capacity Index (FCI) as a tool for establishing vehicle safety priorities by comparing the life year burden of injuries to the burden of fatality in frontal and side automotive crashes. We demonstrate FCI's utility by investigating in detail the resulting disabling injuries and their life year costs. We selected occupants in the 2000-2013 NASS-CDS database involved in frontal and side crashes, merged their injuries with FCI, and then used the merged data to estimate each occupant's overall functional loss. Lifetime functional loss was assessed by combining this measure of impairment with the occupants' expected future life spans, estimated from the Social Security Administration's Actuarial Life Table. Frontal crashes produce a large number of disabling injuries, particularly to the lower extremities. In our population, these crashes are estimated to account for approximately 400,000 life years lost to disability in comparison with 500,000 life years lost to fatality. Victims of side crashes experienced a higher rate of fatality but a significantly lower rate of disabling injury (0.3 vs. 1.0%), resulting in approximately 370,000 life years lost to fatality versus 50,000 life years lost to disability. The burden of disabling injuries to car crash survivors should be considered when setting vehicle safety design priorities. In frontal crashes this burden in life years is similar to the burden attributable to fatality.

Arrays of Molecular Rotors with Triptycene Stoppers: Surface Inclusion in Hexagonal Tris(o-phenylenedioxy)cyclotriphosphazene.

PubMed

Kaleta, Jiří; Dron, Paul I; Zhao, Ke; Shen, Yongqiang; Císařová, Ivana; Rogers, Charles T; Michl, Josef

2015-06-19

A new generation of rod-shaped dipolar molecular rotors designed for controlled insertion into channel arrays in the surface of hexagonal tris(o-phenylenedioxy)cyclotriphosphazene (TPP) has been designed and synthesized. Triptycene is used as a stopper intended to prevent complete insertion, forcing the formation of a surface inclusion. Two widely separated (13)C NMR markers are present in the shaft for monitoring the degree of insertion. The structure of the two-dimensional rotor arrays contained in these surface inclusions was examined by solid-state NMR and X-ray powder diffraction. The NMR markers and the triptycene stopper functioned as designed, but half of the guest molecules were not inserted as deeply into the TPP channels as the other half. As a result, the dipolar rotators were distributed equally in two planes parallel to the crystal surface instead of being located in a single plane as would be required for ferroelectricity. Dielectric spectroscopy revealed rotational barriers of ∼4 kcal/mol but no ferroelectric behavior.

A novel and facile decay path of Criegee intermediates by intramolecular insertion reactions via roaming transition states

NASA Astrophysics Data System (ADS)

Nguyen, Trong-Nghia; Putikam, Raghunath; Lin, M. C.

2015-03-01

We have discovered a new and highly competitive product channel in the unimolecular decay process for small Criegee intermediates, CH2OO and anti/syn-CH3C(H)OO, occurring by intramolecular insertion reactions via a roaming-like transition state (TS) based on quantum-chemical calculations. Our results show that in the decomposition of CH2OO and anti-CH3C(H)OO, the predominant paths directly produce cis-HC(O)OH and syn-CH3C(O)OH acids with >110 kcal/mol exothermicities via loose roaming-like insertion TSs involving the terminal O atom and the neighboring C-H bonds. For syn-CH3C(H)OO, the major decomposition channel occurs by abstraction of a H atom from the CH3 group by the terminal O atom producing CH2C(H)O-OH. At 298 K, the intramolecular insertion process in CH2OO was found to be 600 times faster than the commonly assumed ring-closing reaction.

Deep electrode insertion and sound coding in cochlear implants.

PubMed

Hochmair, Ingeborg; Hochmair, Erwin; Nopp, Peter; Waller, Melissa; Jolly, Claude

2015-04-01

Present-day cochlear implants demonstrate remarkable speech understanding performance despite the use of non-optimized coding strategies concerning the transmission of tonal information. Most systems rely on place pitch information despite possibly large deviations from correct tonotopic placement of stimulation sites. Low frequency information is limited as well because of the constant pulse rate stimulation generally used and, being even more restrictive, of the limited insertion depth of the electrodes. This results in a compromised perception of music and tonal languages. Newly available flexible long straight electrodes permit deep insertion reaching the apical region with little or no insertion trauma. This article discusses the potential benefits of deep insertion which are obtained using pitch-locked temporal stimulation patterns. Besides the access to low frequency information, further advantages of deeply inserted long electrodes are the possibility to better approximate the correct tonotopic location of contacts, the coverage of a wider range of cochlear locations, and the somewhat reduced channel interaction due to the wider contact separation for a given number of channels. A newly developed set of strategies has been shown to improve speech understanding in noise and to enhance sound quality by providing a more "natural" impression, which especially becomes obvious when listening to music. The benefits of deep insertion should not, however, be compromised by structural damage during insertion. The small cross section and the high flexibility of the new electrodes can help to ensure less traumatic insertions as demonstrated by patients' hearing preservation rate. This article is part of a Special Issue entitled . Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Stimulated Brillouin scatter in a magnetized ionospheric plasma.

PubMed

Bernhardt, P A; Selcher, C A; Lehmberg, R H; Rodriguez, S P; Thomason, J F; Groves, K M; McCarrick, M J; Frazer, G J

2010-04-23

High power electromagnetic waves transmitted from the HAARP facility in Alaska can excite low-frequency electrostatic waves by magnetized stimulated Brillouin scatter. Either an ion-acoustic wave with a frequency less than the ion cyclotron frequency (f(CI)) or an electrostatic ion cyclotron (EIC) wave just above f(CI) can be produced. The coupled equations describing the magnetized stimulated Brillouin scatter instability show that the production of both ion-acoustic and EIC waves is strongly influenced by the wave propagation relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions using the HAARP transmitter have confirmed that only ion-acoustic waves are excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The ion composition can be obtained from the measured EIC frequency.

A Taxonomy of Introductory Physics Concepts.

NASA Astrophysics Data System (ADS)

Mokaya, Fridah; Savkar, Amit; Valente, Diego

We have designed and implemented a hierarchical taxonomic classification of physics concepts for our introductory physics for engineers course sequence taught at the University of Connecticut. This classification can be used to provide a mechanism to measure student progress in learning at the level of individual concepts or clusters of concepts, and also as part of a tool to measure effectiveness of teaching pedagogy. We examine our pre- and post-test FCI results broken down by topics using Hestenes et al.'s taxonomy classification for the FCI, and compare these results with those found using our own taxonomy classification. In addition, we expand this taxonomic classification to measure performance in our other course exams, investigating possible correlations in results achieved across different assessments at the individual topic level. UCONN CLAS(College of Liberal Arts and Science).

On the Foundations of the Two Measures Field Theory

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

Guendelman, E. I.; Kaganovich, A. B.

2006-11-03

Two Measures Field Theory (TMT) uses both the Riemannian volume element {radical}(-g)d{sup 4}x and a new one Fcy d4x where the new measure of integration Fcy can be build of four scalar fields. Arguments in favor of TMT, both from the point of view of first principles and from the TMT results are summarized. Possible origin of the TMT and symmetries that protect the structure of TMT are reviewed. It appears that four measure scalar fields treated as 'physical coordinates' allow to define local observables in quantum gravity. The resolution of the old cosmological constant problem as a possible directmore » consequence of the TMT structure is discussed. Other applications of TMT to cosmology and particle physics are also mentioned.« less

16-channel arrayed waveguide grating (AWG) demultiplexer design on SOI wafer for application in CWDM-PON

NASA Astrophysics Data System (ADS)

Juhari, Nurjuliana; Menon, P. Susthitha; Ehsan, Abang Annuar; Shaari, Sahbudin

2015-01-01

Arrayed Waveguide Grating (AWG) functioning as a demultiplexer is designed on SOI platform with rib waveguide structure to be utilized in coarse wavelength division multiplexing-passive optical network (CWDM-PON) systems. Two design approaches; conventional and tapered configuration of AWG was developed with channel spacing of 20 nm that covers the standard transmission spectrum of CWDM ranging from 1311 nm to 1611 nm. The performance of insertion loss for tapered configuration offered the lowest insertion loss of 0.77 dB but the adjacent crosstalk gave non-significant relation for both designs. With average channel spacing of 20.4 nm, the nominal central wavelength of this design is close to the standard CWDM wavelength grid over 484 nm free spectrum range (FSR).

The effects of modeling instruction on high school physics academic achievement

NASA Astrophysics Data System (ADS)

Wright, Tiffanie L.

The purpose of this study was to explore whether Modeling Instruction, compared to traditional lecturing, is an effective instructional method to promote academic achievement in selected high school physics classes at a rural middle Tennessee high school. This study used an ex post facto , quasi-experimental research methodology. The independent variables in this study were the instructional methods of teaching. The treatment variable was Modeling Instruction and the control variable was traditional lecture instruction. The Treatment Group consisted of participants in Physical World Concepts who received Modeling Instruction. The Control Group consisted of participants in Physical Science who received traditional lecture instruction. The dependent variable was gains scores on the Force Concepts Inventory (FCI). The participants for this study were 133 students each in both the Treatment and Control Groups (n = 266), who attended a public, high school in rural middle Tennessee. The participants were administered the Force Concepts Inventory (FCI) prior to being taught the mechanics of physics. The FCI data were entered into the computer-based Statistical Package for the Social Science (SPSS). Two independent samples t-tests were conducted to answer the research questions. There was a statistically significant difference between the treatment and control groups concerning the instructional method. Modeling Instructional methods were found to be effective in increasing the academic achievement of students in high school physics. There was no statistically significant difference between FCI gains scores for gender. Gender was found to have no effect on the academic achievement of students in high school physics classes. However, even though there was not a statistically significant difference, female students' gains scores were higher than male students' gains scores when Modeling Instructional methods of teaching were used. Based on these findings, it is recommended that high school science teachers should use Modeling Instructional methods of teaching daily in their classrooms. A recommendation for further research is to expand the Modeling Instructional methods of teaching into different content areas, (i.e., reading and language arts) to explore academic achievement gains.

Toward equity through participation in Modeling Instruction in introductory university physics

NASA Astrophysics Data System (ADS)

Brewe, Eric; Sawtelle, Vashti; Kramer, Laird H.; O'Brien, George E.; Rodriguez, Idaykis; Pamelá, Priscilla

2010-06-01

We report the results of a five year evaluation of the reform of introductory calculus-based physics by implementation of Modeling Instruction (MI) at Florida International University (FIU), a Hispanic-serving institution. MI is described in the context of FIU’s overall effort to enhance student participation in physics and science broadly. Our analysis of MI from a “participationist” perspective on learning identifies aspects of MI including conceptually based instruction, culturally sensitive instruction, and cooperative group learning, which are consistent with research on supporting equitable learning and participation by students historically under-represented in physics (i.e., Black, Hispanic, women). This study uses markers of conceptual understanding as measured by the Force Concept Inventory (FCI) and odds of success as measured by the ratio of students completing introductory physics and earning a passing grade (i.e., C- or better) by students historically under-represented in physics to reflect equity and participation in introductory physics. FCI pre and post scores for students in MI are compared with lecture-format taught students. Modeling Instruction students outperform students taught in lecture-format classes on post instruction FCI (61.9% vs 47.9%, p<0.001 ), where these benefits are seen across both ethnic and gender comparisons. In addition, we report that the odds of success in MI are 6.73 times greater than in lecture instruction. Both odds of success and FCI scores within Modeling Instruction are further disaggregated by ethnicity and by gender to address the question of equity within the treatment. The results of this disaggregation indicate that although ethnically under-represented students enter with lower overall conceptual understanding scores, the gap is not widened during introductory physics but instead is maintained, and the odds of success for under-represented students is not different from majority students. Women, similarly enter with scores indicating lower conceptual understanding, and over the course of MI this understanding gap increases, yet we do not find differences in the odds of success between men and women. Contrasting these results with the participationist view on learning indicates a movement toward greater equity in introductory physics but also indicates that the instructional environment can be improved.

Methanol Formation via Oxygen Insertion Chemistry in Ices

NASA Astrophysics Data System (ADS)

Bergner, Jennifer B.; Öberg, Karin I.; Rajappan, Mahesh

2017-08-01

We present experimental constraints on the insertion of oxygen atoms into methane to form methanol in astrophysical ice analogs. In gas-phase and theoretical studies this process has previously been demonstrated to have a very low or nonexistent energy barrier, but the energetics and mechanisms have not yet been characterized in the solid state. We use a deuterium UV lamp filtered by a sapphire window to selectively dissociate O2 within a mixture of O2:CH4 and observe efficient production of CH3OH via O(1D) insertion. CH3OH growth curves are fit with a kinetic model, and we observe no temperature dependence of the reaction rate constant at temperatures below the oxygen desorption temperature of 25 K. Through an analysis of side products we determine the branching ratio of ice-phase oxygen insertion into CH4: ˜65% of insertions lead to CH3OH, with the remainder leading instead to H2CO formation. There is no evidence for CH3 or OH radical formation, indicating that the fragmentation is not an important channel and that insertions typically lead to increased chemical complexity. CH3OH formation from O2 and CH4 diluted in a CO-dominated ice similarly shows no temperature dependence, consistent with expectations that insertion proceeds with a small or nonexistent barrier. Oxygen insertion chemistry in ices should therefore be efficient under low-temperature ISM-like conditions and could provide an important channel to complex organic molecule formation on grain surfaces in cold interstellar regions such as cloud cores and protoplanetary disk midplanes.

Enhanced electrical properties of oxide semiconductor thin-film transistors with high conductivity thin layer insertion for the channel region

NASA Astrophysics Data System (ADS)

Nguyen, Cam Phu Thi; Raja, Jayapal; Kim, Sunbo; Jang, Kyungsoo; Le, Anh Huy Tuan; Lee, Youn-Jung; Yi, Junsin

2017-02-01

This study examined the performance and the stability of indium tin zinc oxide (ITZO) thin film transistors (TFTs) by inserting an ultra-thin indium tin oxide (ITO) layer at the active/insulator interface. The electrical properties of the double channel device (ITO thickness of 5 nm) were improved in comparison with the single channel ITZO or ITO devices. The TFT characteristics of the device with an ITO thickness of less than 5 nm were degraded due to the formation of an island-like morphology and the carriers scattering at the active/insulator interface. The 5 nm-thick ITO inserted ITZO TFTs (optimal condition) exhibited a superior field effect mobility (∼95 cm2/V·s) compared with the ITZO-only TFTs (∼34 cm2/V·s). The best characteristics of the TFT devices with double channel layer are due to the lowest surface roughness (0.14 nm) and contact angle (50.1°) that result in the highest hydrophicility, and the most effective adhesion at the surface. Furthermore, the threshold voltage shifts for the ITO/ITZO double layer device decreased to 0.80 and -2.39 V compared with 6.10 and -6.79 V (for the ITZO only device) under positive and negative bias stress, respectively. The falling rates of EA were 0.38 eV/V and 0.54 eV/V for the ITZO and ITO/ITZO bi-layer devices, respectively. The faster falling rate of the double channel devices suggests that the trap density, including interface trap and semiconductor bulk trap, can be decreased by the ion insertion of a very thin ITO film into the ITZO/SiO2 reference device. These results demonstrate that the double active layer TFT can potentially be applied to the flat panel display.

Frequency of DEA 1 antigen in 1037 mongrel and PUREBREED dogs in ITALY.

PubMed

Carli, E; Carminato, A; Ravagnan, S; Capello, K; Antognoni, M T; Miglio, A; Furlanello, T; Proverbio, D; Spada, E; Stefani, A; Mutinelli, F; Vascellari, M

2017-11-29

The prevalence of dog erythrocyte antigen (DEA 1) in canine population is approximately 40-60%. Often data are limited to a small number of breeds and/or dogs. The aims of this study were to evaluate frequency of DEA 1 in a large population of purebred and mongrel dogs including Italian native breeds and to recognize a possible association between DEA 1 and breed, sex, and genetic and phenotypical/functional classifications of breeds. Frequencies of DEA 1 blood group collected from screened/enrolled blood donors and from healthy and sick dogs were retrospectively evaluated. The breed and the sex were recorded when available. DEA 1 blood typing was assessed by immunocromatographic test on K3EDTA blood samples. The prevalence of DEA 1 antigen was statistically related to breed, gender, Fédération Cynologique Internationale (FCI) and genotypic grouping. Sixty-two per cent dogs resulted DEA 1+ and 38% DEA 1-. DEA 1- was statistically associated with Dogo Argentino, Dobermann, German Shepherd, Boxer, Corso dogs, the molossian dogs, the FCI group 1, 2 and 3 and the genetic groups "working dogs" and "mastiff". DEA 1+ was statistically associated with Rottweiler, Briquet Griffon Vendéen, Bernese mountain dog, Golden Retriever, the hunting breeds, the FCI group 4, 6, 7 and 8 and the genetic groups "scent hounds" and "retrievers". No gender association was observed. Data obtained by this work may be clinically useful to drive blood donor enrollment and selection among different breeds.

Assessing students' conceptual knowledge of electricity and magnetism

NASA Astrophysics Data System (ADS)

McColgan, Michele W.; Finn, Rose A.; Broder, Darren L.; Hassel, George E.

2017-12-01

We present the Electricity and Magnetism Conceptual Assessment (EMCA), a new assessment aligned with second-semester introductory physics courses. Topics covered include electrostatics, electric fields, circuits, magnetism, and induction. We have two motives for writing a new assessment. First, we find other assessments such as the Brief Electricity and Magnetism Assessment and the Conceptual Survey on Electricity and Magnetism not well aligned with the topics and content depth of our courses. We want to test introductory physics content at a level appropriate for our students. Second, we want the assessment to yield scores and gains comparable to the widely used Force Concept Inventory (FCI). After five testing and revision cycles, the assessment was finalized in early 2015 and is available online. We present performance results for a cohort of 225 students at Siena College who were enrolled in our algebra- and calculus-based physics courses during the spring 2015 and 2016 semesters. We provide pretest, post-test, and gain analyses, as well as individual question and whole test statistics to quantify difficulty and reliability. In addition, we compare EMCA and FCI scores and gains, and we find that students' FCI scores are strongly correlated with their performance on the EMCA. Finally, the assessment was piloted in an algebra-based physics course at George Washington University (GWU). We present performance results for a cohort of 130 GWU students and we find that their EMCA scores are comparable to the scores of students in our calculus-based physics course.

Treatment summaries, follow-up care instructions, and patient navigation: could they be combined to improve cancer survivor's receipt of follow-up care?

PubMed

Jabson, Jennifer M

2015-12-01

Cancer survivors require follow-up care to ensure early detection of recurrence, management of late/long term effects, preventive screening for early detection of second primary malignancies, as well as other forms of preventive care. But not all survivors receive necessary follow-up care. Combining survivorship care plans and patient navigation may be a successful strategy to improve survivor's receipt of necessary follow-up care. Using data from the 2010 LIVESTRONG online survey of cancer survivors (N = 3854), this study tested associations between receipt of follow-up care instructions (FCI) and treatment summaries (TS) paired with patient navigation (PN), and survivor's receipt of cancer surveillance, preventive cancer screening, and attendance at regular medical appointments. Survivors who received FCI, TS, and patient navigation were the most likely to report attendance at all medical appointments (aOR 4.17, 95% CI 2.30, 7.57, p ≤ .001) and receipt of preventive cancer screening (aOR 3.56, 95% CI 2.28, 5.55, p ≤ .001). Likelihood of receiving follow-up care was greatest when survivors received FCI, TS, and PN. This pairing appeared to be most beneficial for survivor's attendance at medical appointments and receipt of preventive cancer screening. By improving attendance at medical appointments and prevention cancer screening, pairing SCP and PN could benefit survivors through reduced recurrence, earlier recurrence detection, and prevention of second primaries.

Optimum Code Rates for Noncoherent MFSK with Errors and Erasures Decoding over Rayleigh Fading Channels

NASA Technical Reports Server (NTRS)

Ritcey, Adina Matache James A.

1997-01-01

In this paper, we analyze the performance of a communication system employing M-ary frequency shift keying (FSK) modulation with errors-and-erasures decoding using Viterbi ratio threshold technique for erasure insertion, in Rayleigh fading and AWGN channels.

Double emulsions from a capillary array injection microfluidic device.

PubMed

Shang, Luoran; Cheng, Yao; Wang, Jie; Ding, Haibo; Rong, Fei; Zhao, Yuanjin; Gu, Zhongze

2014-09-21

A facile microfluidic device was developed by inserting an annular capillary array into a collection channel for single-step emulsification of double emulsions. By inserting multiple inner-phase solutions into the capillary array, multicomponent double emulsions or microcapsules with inner droplets of different content could also be obtained from the device.

46 CFR 184.510 - Recommended emergency broadcast instructions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... NAME), (INSERT VESSEL'S NAME), (INSERT VESSEL'S CALL SIGN), OVER.” (5) Release the microphone button... VESSEL'S NAME & CALL SIGN).” (14) If your situation permits, stand by the radio to await further... 2182 kHz. (Channel 16 VHF and 2182 kHz on SSB are for emergency and calling purposes only.) (3) Press...

Investigation of AWG demultiplexer based SOI for CWDM application

NASA Astrophysics Data System (ADS)

Juhari, Nurjuliana; Susthitha Menon, P.; Shaari, Sahbudin; Annuar Ehsan, Abang

2017-11-01

9-channel Arrayed Waveguide Grating (AWG) demultiplexer for conventional and tapered structure were simulated using beam propagation method (BPM) with channel spacing of 20 nm. The AWG demultiplexer was design using high refractive index (n 3.47) material namely silicon-on-insulator (SOI) with rib waveguide structure. The characteristics of insertion loss, adjacent crosstalk and output spectrum response at central wavelength of 1.55 μm for both designs were compared and analyzed. The conventional AWG produced a minimum insertion loss of 6.64 dB whereas the tapered AWG design reduced the insertion loss by 2.66 dB. The lowest adjacent crosstalk value of -16.96 dB was obtained in the conventional AWG design and this was much smaller compared to the tapered AWG design where the lowest crosstalk value is -17.23 dB. Hence, a tapered AWG design significantly reduces the insertion loss but has a slightly higher adjacent crosstalk compared to the conventional AWG design. On the other hand, the output spectrum responses that are obtained from both designs were close to the Coarse Wavelength Division Multiplexing (CWDM) wavelength grid.

A novel and facile decay path of Criegee intermediates by intramolecular insertion reactions via roaming transition states

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

Nguyen, Trong-Nghia; Department of Physical Chemistry, Hanoi University of Science and Technology, Hanoi; Putikam, Raghunath

2015-03-28

We have discovered a new and highly competitive product channel in the unimolecular decay process for small Criegee intermediates, CH{sub 2}OO and anti/syn-CH{sub 3}C(H)OO, occurring by intramolecular insertion reactions via a roaming-like transition state (TS) based on quantum-chemical calculations. Our results show that in the decomposition of CH{sub 2}OO and anti-CH{sub 3}C(H)OO, the predominant paths directly produce cis-HC(O)OH and syn-CH{sub 3}C(O)OH acids with >110 kcal/mol exothermicities via loose roaming-like insertion TSs involving the terminal O atom and the neighboring C–H bonds. For syn-CH{sub 3}C(H)OO, the major decomposition channel occurs by abstraction of a H atom from the CH{sub 3} groupmore » by the terminal O atom producing CH{sub 2}C(H)O–OH. At 298 K, the intramolecular insertion process in CH{sub 2}OO was found to be 600 times faster than the commonly assumed ring-closing reaction.« less

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

Tran, Ich C.; Tunuguntla, Ramya H.; Kim, Kyunghoon

Carbon nanotube porins (CNTPs), small segments of carbon nanotubes capable of forming defined pores in lipid membranes, are important future components for bionanoelectronic devices as they could provide a robust analog of biological membrane channels. Furthermore, in order to control the incorporation of these CNT channels into lipid bilayers, it is important to understand the structure of the CNTPs before and after insertion into the lipid bilayer as well as the impact of such insertion on the bilayer structure. Here we employed a noninvasive in situ probe, small-angle X-ray scattering, to study the integration of CNT porins into dioleoylphosphatidylcholine bilayers.more » These results show that CNTPs in solution are stabilized by a monolayer of lipid molecules wrapped around their outer surface. We also demonstrate that insertion of CNTPs into the lipid bilayer results in decreased bilayer thickness with the magnitude of this effect increasing with the concentration of CNTPs.« less

The acoustic sensor for rapid analysis of bacterial cells in the conductive suspensions.

PubMed

Borodina, I A; Zaitsev, B D; Guliy, O; Teplykh, A A; Shikhabudinov, A M

2017-11-01

The possibility of using the acoustic sensor on the basis of a two-channel delay line for rapid analysis of bacterial cells in the conductive suspensions was investigated. The dependencies of change in phase and insertion loss of output signal of the sensor on conductivity of buffer solution with various concentrations of cells due to a specific interaction "bacterial cells - mini-antibodies" for electrically open and electrically shorted channels of delay line were measured. It has been found that these changes have the most values for the electrically open channel. It has been also shown that the sensor rapidly responds to the specific interaction and the time stabilization of the phase and insertion loss of output signal is less than 10min. Copyright © 2017 Elsevier B.V. All rights reserved.

The core domain as the force sensor of the yeast mechanosensitive TRP channel.

PubMed

Su, Zhenwei; Anishkin, Andriy; Kung, Ching; Saimi, Yoshiro

2011-12-01

Stretch-activated conductances are commonly encountered in careful electric recordings. Those of known proteins (TRP, MscL, MscS, K(2p), Kv, etc.) all share a core, which houses the ion pathway and the gate, but no recognizable force-sensing domain. Like animal TRPs, the yeast TRPY1 is polymodal, activated by stretch force, Ca(2+), etc. To test whether its S5-S6 core senses the stretch force, we tried to uncouple it from the peripheral domains by strategic peptide insertions to block the covalent core-periphery interactions. Insertion of long unstructured peptides should distort, if not disrupt, protein structures that transmit force. Such insertions between S6 and the C-terminal tail largely removed Ca(2+) activation, showing their effectiveness. However, such insertions as well as those between S5 and the N-terminal region, which includes S1-S4, did not significantly alter mechanosensitivity. Even insertions at both locations flanking the S5-S6 core did not much alter mechanosensitivity. Tryptophan scanning mutations in S5 were also constructed to perturb possible noncovalent core-periphery contacts. The testable tryptophan mutations also have little or no effects on mechanosensitivity. Boltzmann fits of the wild-type force-response curves agree with a structural homology model for a stretch-induced core expansion of ~2 nm(2) upon opening. We hypothesize that membrane tension pulls on S5-S6, expanding the core and opening the TRPY1 gate. The core being the major force sensor offers the simplest, though not the only, explanation of why so many channels of disparate designs are mechanically sensitive. Compared with the bacterial MscL, TRPY1 is much less sensitive to force, befitting a polymodal channel that relies on multiple stimuli.

Role of Transmembrane Potential and Defects on the Permeabilization of Lipid Bilayers by Alamethicin, an Ion-Channel-Forming Peptide.

PubMed

Su, ZhangFei; Shodiev, Muzaffar; Leitch, J Jay; Abbasi, Fatemeh; Lipkowski, Jacek

2018-05-29

The insertion and ion-conducting channel properties of alamethicin reconstituted into a 1,2-di- O-phytanyl- sn-glycero-3-phosphocholine bilayer floating on the surface of a gold (111) electrode modified with a 1-thio-β-d-glucose (β-Tg) self-assembled monolayer were investigated using a combination of electrochemical impedance spectroscopy (EIS) and polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). The hydrophilic β-Tg monolayer separated the bilayer from the gold substrate and created a water-rich spacer region, which better represents natural cell membranes. The EIS measurements acquired information about the membrane resistivity (a measure of membrane porosity), and the PM-IRRAS experiments provided insight into the conformation and orientation of the membrane constituents as a function of the transmembrane potential. The results showed that the presence of alamethicin had a small effect on the conformation and orientation of phospholipid molecules within the bilayer for all studied potentials. In contrast, the alamethicin peptides assumed a surface state, where the helical axes adopted a large tilt angle with respect to the surface normal, at small transmembrane potentials, and inserted into the bilayer at sufficiently negative transmembrane potentials forming pores, which behaved as barrel-stave ion channels for ionic transport across the membrane. The results indicated that insertion of alamethincin peptides into the bilayer was driven by the dipole-field interactions and that the transitions between the inserted and surface states were electrochemically reversible. Additionally, the EIS measurements performed on phospholipid bilayers without alamethicin also showed that the application of negative transmembrane potentials introduces defects into the bilayer. The membrane resistances measured in both the absence and presence of alamethicin show similar dependencies on the electrode potential, suggesting that the insertion of the peptide may also be assisted by the electroporation of the membrane. The findings in this study provide new insights into the mechanism of alamethicin insertion into phospholipid bilayers.

[The contribution of different cochlear insertion region to Mandarin speech perception in users of cochlear implant].

PubMed

Qi, Beier; Liu, Bo; Liu, Sha; Liu, Haihong; Dong, Ruijuan; Zhang, Ning; Gong, Shusheng

2011-05-01

To study the effect of cochlear electrode coverage and different insertion region on speech recognition, especially tone perception of cochlear implant users whose native language is Mandarin Chinese. Setting seven test conditions by fitting software. All conditions were created by switching on/off respective channels in order to simulate different insertion position. Then Mandarin CI users received 4 Speech tests, including Vowel Identification test, Consonant Identification test, Tone Identification test-male speaker, Mandarin HINT test (SRS) in quiet and noise. To all test conditions: the average score of vowel identification was significantly different, from 56% to 91% (Rank sum test, P < 0.05). The average score of consonant identification was significantly different, from 72% to 85% (ANOVNA, P < 0.05). The average score of Tone identification was not significantly different (ANOVNA, P > 0.05). However the more channels activated, the higher scores obtained, from 68% to 81%. This study shows that there is a correlation between insertion depth and speech recognition. Because all parts of the basement membrane can help CI users to improve their speech recognition ability, it is very important to enhance verbal communication ability and social interaction ability of CI users by increasing insertion depth and actively stimulating the top region of cochlear.

Placement of percutaneous transhepatic biliary stent using a silicone drain with channels

PubMed Central

Yoshida, Hiroshi; Mamada, Yasuhiro; Taniai, Nobuhiko; Mineta, Sho; Mizuguchi, Yoshiaki; Kawano, Yoichi; Sasaki, Junpei; Nakamura, Yoshiharu; Aimoto, Takayuki; Tajiri, Takashi

2009-01-01

This report describes a method for percutaneous transhepatic biliary stenting with a BLAKE Silicone Drain, and discusses the usefulness of placement of the drain connected to a J-VAC Suction Reservoir for the treatment of stenotic hepaticojejunostomy. Percutaneous transhepatic biliary drainage was performed under ultrasonographic guidance in a patient with stenotic hepaticojejunostomy after hepatectomy for hepatic hilum malignancy. The technique used was as follows. After dilatation of the drainage root, an 11-Fr tube with several side holes was passed through the stenosis of the hepaticojejunostomy. A 10-Fr BLAKE Silicone Drain is flexible, which precludes one-step insertion. One week after insertion of the 11-Fr tube, a 0.035-inch guidewire was inserted into the tube. After removal of the 11-Fr tube, the guidewire was put into the channel of a 10-Fr BLAKE Silicone Drain. The drain was inserted into the jejunal limb through the intrahepatic bile duct and was connected to a J-VAC Suction Reservoir. Low-pressure continued suction was applied. Patients can be discharged after insertion of the 10-Fr BLAKE Silicone Drain connected to the J-VAC Suction Reservoir. Placement of a percutaneous transhepatic biliary stent using a 10-Fr BLAKE Silicone Drain connected to a J-VAC Suction Reservoir is useful for the treatment of stenotic hepaticojejunostomy. PMID:19725159

Methanol Formation via Oxygen Insertion Chemistry in Ices

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

Bergner, Jennifer B.; Öberg, Karin I.; Rajappan, Mahesh

We present experimental constraints on the insertion of oxygen atoms into methane to form methanol in astrophysical ice analogs. In gas-phase and theoretical studies this process has previously been demonstrated to have a very low or nonexistent energy barrier, but the energetics and mechanisms have not yet been characterized in the solid state. We use a deuterium UV lamp filtered by a sapphire window to selectively dissociate O{sub 2} within a mixture of O{sub 2}:CH{sub 4} and observe efficient production of CH{sub 3}OH via O({sup 1}D) insertion. CH{sub 3}OH growth curves are fit with a kinetic model, and we observemore » no temperature dependence of the reaction rate constant at temperatures below the oxygen desorption temperature of 25 K. Through an analysis of side products we determine the branching ratio of ice-phase oxygen insertion into CH{sub 4}: ∼65% of insertions lead to CH{sub 3}OH, with the remainder leading instead to H{sub 2}CO formation. There is no evidence for CH{sub 3} or OH radical formation, indicating that the fragmentation is not an important channel and that insertions typically lead to increased chemical complexity. CH{sub 3}OH formation from O{sub 2} and CH{sub 4} diluted in a CO-dominated ice similarly shows no temperature dependence, consistent with expectations that insertion proceeds with a small or nonexistent barrier. Oxygen insertion chemistry in ices should therefore be efficient under low-temperature ISM-like conditions and could provide an important channel to complex organic molecule formation on grain surfaces in cold interstellar regions such as cloud cores and protoplanetary disk midplanes.« less

Preparation of high temperature gas-cooled reactor fuel element

DOEpatents

Bradley, Ronnie A.; Sease, John D.

1976-01-01

This invention relates to a method for the preparation of high temperature gas-cooled reactor (HTGR) fuel elements wherein uncarbonized fuel rods are inserted in appropriate channels of an HTGR fuel element block and the entire block is inserted in an autoclave for in situ carbonization under high pressure. The method is particularly applicable to remote handling techniques.

Nonaxisymmetric modelling in BOUT++; toward global edge fluid turbulence in stellarators

NASA Astrophysics Data System (ADS)

Shanahan, Brendan; Hill, Peter; Dudson, Ben

2016-10-01

As Wendelstein 7-X has been optimized for neoclassical transport, turbulent transport could potentially become comparable to neoclassical losses. Furthermore, the imminent installation of an island divertor merits global edge modelling to determine heat flux profiles and the efficacy of the system. Currently, however, nonaxisymmetric edge plasma modelling is limited to either steady state (non-turbulent) transport modelling, or computationally expensive gyrokinetics. The implementation of the Flux Coordinate Independent (FCI) approach to parallel derivatives has allowed the extension of the BOUT++ edge fluid turbulence framework to nonaxisymmetric geometries. Here we first investigate the implementation of the FCI method in BOUT++ by modelling diffusion equations in nonaxisymmetric geometries with and without boundary interaction, and quantify the inherent error. We then present the results of non-turbulent transport modelling and compare with analytical theory. The ongoing extension of BOUT++ to nonaxisymmetric configurations, and the prospects of stellarator edge fluid turbulence simulations will be discussed.

Quantum Chemistry on Quantum Computers: A Polynomial-Time Quantum Algorithm for Constructing the Wave Functions of Open-Shell Molecules.

PubMed

Sugisaki, Kenji; Yamamoto, Satoru; Nakazawa, Shigeaki; Toyota, Kazuo; Sato, Kazunobu; Shiomi, Daisuke; Takui, Takeji

2016-08-18

Quantum computers are capable to efficiently perform full configuration interaction (FCI) calculations of atoms and molecules by using the quantum phase estimation (QPE) algorithm. Because the success probability of the QPE depends on the overlap between approximate and exact wave functions, efficient methods to prepare accurate initial guess wave functions enough to have sufficiently large overlap with the exact ones are highly desired. Here, we propose a quantum algorithm to construct the wave function consisting of one configuration state function, which is suitable for the initial guess wave function in QPE-based FCI calculations of open-shell molecules, based on the addition theorem of angular momentum. The proposed quantum algorithm enables us to prepare the wave function consisting of an exponential number of Slater determinants only by a polynomial number of quantum operations.

Gender Differences in Both Force Concept Inventory and Introductory Physics Performance

NASA Astrophysics Data System (ADS)

Docktor, Jennifer; Heller, Kenneth

2008-10-01

We present data from a decade of introductory calculus-based physics courses for science and engineering students at the University of Minnesota taught using cooperative group problem solving. The data include 40 classes with more than 5500 students taught by 22 different professors. The average normalized gain for males is 0.4 for these large classes that emphasized problem solving. Female students made up approximately 20% of these classes. We present relationships between pre and post Force Concept Inventory (FCI) scores, course grades, and final exam scores for females and males. We compare our results with previous studies from Harvard [2] and the University of Colorado [3,4]. Our data show there is a significant gender gap in pre-test FCI scores that persists post-instruction although there is essentially no gender difference in course performance as determined by course grade.

Accelerating Full Configuration Interaction Calculations for Nuclear Structure

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

Yang, Chao; Sternberg, Philip; Maris, Pieter

2008-04-14

One of the emerging computational approaches in nuclear physics is the full configuration interaction (FCI) method for solving the many-body nuclear Hamiltonian in a sufficiently large single-particle basis space to obtain exact answers - either directly or by extrapolation. The lowest eigenvalues and correspondingeigenvectors for very large, sparse and unstructured nuclear Hamiltonian matrices are obtained and used to evaluate additional experimental quantities. These matrices pose a significant challenge to the design and implementation of efficient and scalable algorithms for obtaining solutions on massively parallel computer systems. In this paper, we describe the computational strategies employed in a state-of-the-art FCI codemore » MFDn (Many Fermion Dynamics - nuclear) as well as techniques we recently developed to enhance the computational efficiency of MFDn. We will demonstrate the current capability of MFDn and report the latest performance improvement we have achieved. We will also outline our future research directions.« less

Nanoscale multireference quantum chemistry: full configuration interaction on graphical processing units.

PubMed

Fales, B Scott; Levine, Benjamin G

2015-10-13

Methods based on a full configuration interaction (FCI) expansion in an active space of orbitals are widely used for modeling chemical phenomena such as bond breaking, multiply excited states, and conical intersections in small-to-medium-sized molecules, but these phenomena occur in systems of all sizes. To scale such calculations up to the nanoscale, we have developed an implementation of FCI in which electron repulsion integral transformation and several of the more expensive steps in σ vector formation are performed on graphical processing unit (GPU) hardware. When applied to a 1.7 × 1.4 × 1.4 nm silicon nanoparticle (Si72H64) described with the polarized, all-electron 6-31G** basis set, our implementation can solve for the ground state of the 16-active-electron/16-active-orbital CASCI Hamiltonian (more than 100,000,000 configurations) in 39 min on a single NVidia K40 GPU.

Micro-droplet formation via 3D printed micro channel

NASA Astrophysics Data System (ADS)

Jian, Zhen; Zhang, Jiaming; Li, Erqiang; Thoroddsen, Sigurdur T.

2016-11-01

Low cost, fast-designed and fast-fabricated 3D micro channel was used to create micro-droplets. Capillary with an outer diameter of 1.5 mm and an inner diameter of 150 μm was inserted into a 3D printed cylindrical channel with a diameter of 2 mm . Flow rate of the two inlets, insert depth, liquid (density, viscosity and surface tension) and solid (roughness, contact angle) properties all play a role in the droplet formation. Different regimes - dripping, jetting, unstable state - were observed in the micro-channel on varying these parameters. With certain parameter combinations, successive formation of micro-droplets with equal size was observed and its size can be much smaller than the smallest channel size. Based on our experimental results, the droplet formation via 3D printed micro T-junction was investigated through direct numerical simulations with a code called Gerris. Reynolds numbers Re = ρUL / μ and Weber numbers We = ρU2 L / σ of the two liquids were introduced to measure the liquid effect. The parameter regime where different physical dynamics occur was studied and the regime transition was observed with certain threshold values. Qualitative and quantitative analysis were performed as well between simulations and experiments.

Effect of Modeling Instruction on Concept Knowledge Among Ninth Grade Physics Students

NASA Astrophysics Data System (ADS)

Ditmore, Devin Alan

A basic knowledge of physics concepts is the gateway to success through high-paying careers in science, technology, engineering, and mathematics (STEM). Many students show little understanding of concepts following traditional physics instruction. As an alternative to current lecture-based approaches for high school physics instruction, Piaget's theory of cognitive development supports using real scientific experiences to lead learners from concrete to formal understanding of complex concepts. Modeling instruction (MI) is a pedagogy that guides learners through genuine scientific experiences. This project study analyzed the effects of MI on 9th grade physics students' gains on the test measuring mastery of physics concepts, Force Concept Inventory (FCI). A quasi-experimental design was used to compare the FCI scores of a traditional lecture-taught control group to a treatment group taught using MI. A t test t(-.201) = 180.26, p = .841 comparing the groups and an analysis of variance F(2,181) = 5.20 comparing female to male students indicated MI had no significant positive effect on students. A partial eta squared of the effect size showed that 5.4% of the variance in FCI gains was accounted for by gender, favoring female participants for both groups. The significant relationship between content and gender bears further inquiry. A lesson plan guide was designed to help teachers use computer simulation technology within the MI curriculum. The project promotes positive social change by exploring further ways to help adolescents experience success in physics at the beginning of high school, leading to future success in all STEM areas.

GRILLIX: a 3D turbulence code based on the flux-coordinate independent approach

NASA Astrophysics Data System (ADS)

Stegmeir, Andreas; Coster, David; Ross, Alexander; Maj, Omar; Lackner, Karl; Poli, Emanuele

2018-03-01

The GRILLIX code is presented with which plasma turbulence/transport in various geometries can be simulated in 3D. The distinguishing feature of the code is that it is based on the flux-coordinate independent approach (FCI) (Hariri and Ottaviani 2013 Comput. Phys. Commun. 184 2419; Stegmeir et al 2016 Comput. Phys. Commun. 198 139). Cylindrical or Cartesian grids are used on which perpendicular operators are discretised via standard finite difference methods and parallel operators via a field line tracing and interpolation procedure (field line map). This offers a very high flexibility with respect to geometry, especially a separatrix with X-point(s) or a magnetic axis can be treated easily in contrast to approaches which are based on field aligned coordinates and suffer from coordinate singularities. Aiming finally for simulation of edge and scrape-off layer (SOL) turbulence, an isothermal electrostatic drift-reduced Braginskii model (Zeiler et al 1997 Phys. Plasmas 4 2134) has been implemented in GRILLIX. We present the numerical approach, which is based on a toroidally staggered formulation of the FCI, we show verification of the code with the method of manufactured solutions and show a benchmark based on a TORPEX blob experiment, previously performed by several edge/SOL codes (Riva et al 2016 Plasma Phys. Control. Fusion 58 044005). Examples for slab, circular, limiter and diverted geometry are presented. Finally, the results show that the FCI approach in general and GRILLIX in particular are viable approaches in order to tackle simulation of edge/SOL turbulence in diverted geometry.

Students' proficiency scores within multitrait item response theory

NASA Astrophysics Data System (ADS)

Scott, Terry F.; Schumayer, Daniel

2015-12-01

In this paper we present a series of item response models of data collected using the Force Concept Inventory. The Force Concept Inventory (FCI) was designed to poll the Newtonian conception of force viewed as a multidimensional concept, that is, as a complex of distinguishable conceptual dimensions. Several previous studies have developed single-trait item response models of FCI data; however, we feel that multidimensional models are also appropriate given the explicitly multidimensional design of the inventory. The models employed in the research reported here vary in both the number of fitting parameters and the number of underlying latent traits assumed. We calculate several model information statistics to ensure adequate model fit and to determine which of the models provides the optimal balance of information and parsimony. Our analysis indicates that all item response models tested, from the single-trait Rasch model through to a model with ten latent traits, satisfy the standard requirements of fit. However, analysis of model information criteria indicates that the five-trait model is optimal. We note that an earlier factor analysis of the same FCI data also led to a five-factor model. Furthermore the factors in our previous study and the traits identified in the current work match each other well. The optimal five-trait model assigns proficiency scores to all respondents for each of the five traits. We construct a correlation matrix between the proficiencies in each of these traits. This correlation matrix shows strong correlations between some proficiencies, and strong anticorrelations between others. We present an interpretation of this correlation matrix.

78 FR 49468 - Arturo Guillermo Nino, Inmate Number #04908-379, FCI Beaumont Low, Federal Correctional Institute...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-14

... to Mexico a defense article, that is to wit: several AK-47 type rifles and magazines, without having..., or business organization related to Nino by affiliation, ownership, control or position of...

Flexible ambipolar organic field-effect transistors with reverse-offset-printed silver electrodes for a complementary inverter.

PubMed

Park, Junsu; Kim, Minseok; Yeom, Seung-Won; Ha, Hyeon Jun; Song, Hyenggun; Min Jhon, Young; Kim, Yun-Hi; Ju, Byeong-Kwon

2016-06-03

We report ambipolar organic field-effect transistors and complementary inverter circuits with reverse-offset-printed (ROP) Ag electrodes fabricated on a flexible substrate. A diketopyrrolopyrrole-based co-polymer (PDPP-TAT) was used as the semiconductor and poly(methyl methacrylate) was used as the gate insulator. Considerable improvement is observed in the n-channel electrical characteristics by inserting a cesium carbonate (Cs2CO3) as the electron-injection/hole-blocking layer at the interface between the semiconductors and the electrodes. The saturation mobility values are 0.35 cm(2) V(-1) s(-1) for the p-channel and 0.027 cm(2) V(-1) s(-1) for the n-channel. A complementary inverter is demonstrated based on the ROP process, and it is selectively controlled by the insertion of Cs2CO3 onto the n-channel region via thermal evaporation. Moreover, the devices show stable operation during the mechanical bending test using tensile strains ranging from 0.05% to 0.5%. The results confirm that these devices have great potential for use in flexible and inexpensive integrated circuits over a large area.

Functional assay for T4 lysozyme-engineered G protein-coupled receptors with an ion channel reporter.

PubMed

Niescierowicz, Katarzyna; Caro, Lydia; Cherezov, Vadim; Vivaudou, Michel; Moreau, Christophe J

2014-01-07

Structural studies of G protein-coupled receptors (GPCRs) extensively use the insertion of globular soluble protein domains to facilitate their crystallization. However, when inserted in the third intracellular loop (i3 loop), the soluble protein domain disrupts their coupling to G proteins and impedes the GPCRs functional characterization by standard G protein-based assays. Therefore, activity tests of crystallization-optimized GPCRs are essentially limited to their ligand binding properties using radioligand binding assays. Functional characterization of additional thermostabilizing mutations requires the insertion of similar mutations in the wild-type receptor to allow G protein-activation tests. We demonstrate that ion channel-coupled receptor technology is a complementary approach for a comprehensive functional characterization of crystallization-optimized GPCRs and potentially of any engineered GPCR. Ligand-induced conformational changes of the GPCRs are translated into electrical signal and detected by simple current recordings, even though binding of G proteins is sterically blocked by the added soluble protein domain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of graphene tunnel barrier on Schottky barrier height of Heusler alloy Co2MnSi/graphene/n-Ge junction

NASA Astrophysics Data System (ADS)

Gui-fang, Li; Jing, Hu; Hui, Lv; Zhijun, Cui; Xiaowei, Hou; Shibin, Liu; Yongqian, Du

2016-02-01

We demonstrate that the insertion of a graphene tunnel barrier between Heusler alloy Co2MnSi and the germanium (Ge) channel modulates the Schottky barrier height and the resistance-area product of the spin diode. We confirm that the Fermi level is depinned and a reduction in the electron Schottky barrier height (SBH) occurs following the insertion of the graphene layer between Co2MnSi and Ge. The electron SBH is modulated in the 0.34 eV-0.61 eV range. Furthermore, the transport mechanism changes from rectifying to symmetric tunneling following the insertion. This behavior provides a pathway for highly efficient spin injection from a Heusler alloy into a Ge channel with high electron and hole mobility. Project supported by the National Natural Science Foundation of China (Grant No. 61504107) and the Fundamental Research Funds for the Central Universities, China (Grant Nos. 3102014JCQ01059 and 3102015ZY043).

Damping element for reducing the vibration of an airfoil

DOEpatents

Campbell, Christian X; Marra, John J

2013-11-12

An airfoil (10) is provided with a tip (12) having an opening (14) to a center channel (24). A damping element (16) is inserted within the opening of the center channel, to reduce an induced vibration of the airfoil. The mass of the damping element, a spring constant of the damping element within the center channel, and/or a mounting location (58) of the damping element within the center channel may be adjustably varied, to shift a resonance frequency of the airfoil outside a natural operating frequency of the airfoil.

Fluid delivery manifolds and microfluidic systems

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

Renzi, Ronald F.; Sommer, Gregory J.; Singh, Anup K.

2017-02-28

Embodiments of fluid distribution manifolds, cartridges, and microfluidic systems are described herein. Fluid distribution manifolds may include an insert member and a manifold base and may define a substantially closed channel within the manifold when the insert member is press-fit into the base. Cartridges described herein may allow for simultaneous electrical and fluidic interconnection with an electrical multiplex board and may be held in place using magnetic attraction.

Flight Crew Integration (FCI) ISS Crew Comments Database & Products Summary

NASA Technical Reports Server (NTRS)

Schuh, Susan

2016-01-01

This Crew Debrief Data provides support for design and development of vehicles, hardware, requirements, procedures, processes, issue resolution, lessons learned, consolidation and trending for current Programs; and much of the data is also used to support development of future Programs.

Micro Machining of Injection Mold Inserts for Fluidic Channel of Polymeric Biochips

PubMed Central

Jung, Woo-Chul; Heo, Young-Moo; Yoon, Gil-Sang; Shin, Kwang-Ho; Chang, Sung-Ho; Kim, Gun-Hee; Cho, Myeong-Woo

2007-01-01

Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip), has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for microfluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

Risk based meat hygiene--examples on food chain information and visual meat inspection.

PubMed

Ellerbroek, Lüppo

2007-08-01

The Regulation (EC) No. 854/2004 refers in particularly to a broad spectrum of official supervision of products of animal origin. The supervision should be based on the most current relevant information which is available. The proposal presented includes forms for implementation of Food Chain Information (FCI) as laid down in the Regulation (EC) No. 853/2004 as well as suggestions for the implementation of the visual inspection and criteria for a practical approach to assist the competent authority and the business operator. These suggestions are summarised in two forms including the FCI and practical information from the farm of origin as well as from the slaughterhouse needed for the competent authority to permit the visual meat inspection of fattening pigs. The requested information from the farm level include i.e. an animal loss rate during the fattening period and diagnostic findings of carcasses and respectively on organs of the animals during meat inspection procedure. The evaluation of findings in liver and pleura at the slaughterhouse level indicate a correlation to the general health status of the fattening conditions at farm level. The criteria developed are in principle suited for a "gold standard" of the health status of fattening pigs and the criteria may serve as practical implementation of the term Good Farming Practice in relation to consumer protection. Only for fattening pigs deriving from farms fulfilling this "gold standard" the visual meat inspection shall be permitted. It is proposed to integrate the two forms for FCI and additional information for authorisation of visual meat inspection for fattening pigs in the working document of the DG SANCO titled "Commission regulation of laying down specific rules on official controls for the inspection of meat" (SANCO/2696/2006).

Adrenocortical reserves in hyperthyroidism.

PubMed

Agbaht, Kemal; Gullu, Sevim

2014-02-01

Explicit data regarding the changes in adrenocortical reserves during hyperthyroidism do not exist. We aimed to document the capability (response) of adrenal gland to secrete cortisol and DHEA-S during hyperthyroidism compared to euthyroidism, and to describe factors associated with these responses. A standard-dose (0.25 mg/i.v.) ACTH stimulation test was performed to the same patients before hyperthyroidism treatment, and after attainment of euthyroidism. Baseline cortisol (Cor(0)), DHEA-S (DHEA-S(0)), cortisol binding globulin (CBG), ACTH, calculated free cortisol (by Coolen's equation = CFC), free cortisol index (FCI), 60-min cortisol (Cor(60)), and DHEA-S (DHEA-S(60)), delta cortisol (ΔCor), delta DHEA-S (ΔDHEA-S) responses were evaluated. Forty-one patients [22 females, 49.5 ± 15.2 years old, 32 Graves disease, nine toxic nodular goiter] had similar Cor(0), DHEA-S(0), CFC, FCI, and DHEA-S(60) in hyperthyroid and euthyroid states. Cor(60), ΔCor, and ΔDHEA-S were lower in hyperthyroidism. In four (10 %) patients the peak ACTH-stimulated cortisol values were lower than 18 μg/dL. When the test repeated after attainment of euthyroidism, all of the patients had normal cortisol response. Regression analysis demonstrated an independent association of Cor(60) with free T3 in hyperthyroidism. However, the predictors of CFC, FCI, and DHEA-S levels were serum creatinine levels in hyperthyroidism, and both creatinine and transaminase levels in euthyroidism. ACTH-stimulated peak cortisol, delta cortisol, and delta DHEA-S levels are decreased during hyperthyroidism, probably due to increased turnover. Since about 10 % of the subjects with hyperthyroidism are at risk for adrenal insufficiency, clinicians dealing with Graves' disease should be alert to the possibility of adrenal insufficiency during hyperthyroid stage.

Epidemiology of ocular disorders presumed to be inherited in three large Italian dog breeds in Italy.

PubMed

Guandalini, Adolfo; Di Girolamo, Nicola; Santillo, Daniele; Andreani, Valentina; Corvi, Roberta; Bandini, Marina; Peruccio, Claudio

2017-09-01

To describe the epidemiology and the types of eye disorders that are presumed to be inherited (PIED) in three large Italian dog breeds. Three large Italian dog breeds: Neapolitan Mastiff (FCI code: 197), Maremma Sheepdog (FCI code: 201), and Italian Corso dog (FCI code: 343). All dogs that underwent a complete ophthalmic examination between 1992 and 2012 were included in this prospective observational study. The prevalence of eye disorders with 95% confidence intervals was reported for presumed healthy dogs and for dogs referred to a veterinary center for an ophthalmic consultation. Univariate and multivariate logistic regression techniques were used to generate odds ratios. Of 605 dogs examined during the study period, 351 dogs were affected by at least one PIED (58%; 95% CI: 54-62%). The prevalence of PIED was significantly lower in dogs presented for ophthalmic examination (53.8%) as compared to presumed healthy dogs (62.2%)(OR: 1.4; 95% CI: 1.02-1.9; P = 0.037). Also after multivariate adjustment for the period of observation, the odds of Neapolitan Mastiff (92.1%; OR: 21.4; 95% CI: 11.1-41.4) and of Cane Corso (57.7%; OR: 2.5; 95% CI: 1.7-3.6) suffering a PIED were greater than the Maremma Sheepdog (35.4%). The most common PIED in each breed were entropion (24.3% of all the PIED) in the Neapolitan Mastiff, ectropion (36.6%) in the Corso dog, and cataract (27.9%) in the Maremma Sheepdog. Clinicians should be aware that three large Italian dog breeds frequently suffer PIED. Breed standards should be reconsidered, and breeding programs should be directed at limiting such disorders. © 2016 American College of Veterinary Ophthalmologists.

From the Cover: Understanding nature's design for a nanosyringe

NASA Astrophysics Data System (ADS)

Lopez, Carlos F.; Nielsen, Steve O.; Moore, Preston B.; Klein, Michael L.

2004-03-01

Synthetic and natural peptide assemblies can possess transport or conductance activity across biomembranes through the formation of nanopores. The fundamental mechanisms of membrane insertion necessary for antimicrobial or synthetic pore formation are poorly understood. We observe a lipid-assisted mechanism for passive insertion into a model membrane from molecular dynamics simulations. The assembly used in the study, a generic nanotube functionalized with hydrophilic termini, is assisted in crossing the membrane core by transleaflet lipid flips. Lipid tails occlude a purely hydrophobic nanotube. The observed insertion mechanism requirements for hydrophobic-hydrophilic matching have implications for the design of synthetic channels and antibiotics.

Esthetic abutment design for angulated screw channels: A technical report.

PubMed

Sakamoto, Satoshi; Ro, Munehiko; Al Ardah, Aladdin; Goodacre, Charles

2017-11-15

Angulated screw channel system abutments (ASCs) have recently been introduced to address the problem with visible screw access that may compromise esthetics. ASCs allow the screw access to be modified up to 25 degrees relative to the implant axis. However, a widened channel, which may cause thinning of the facial ceramic, is needed at the implant screw head to allow for proper engagement of the screwdriver. This technical report introduces a custom titanium insert design, the Satoshi Sakamoto (SS) abutment. The SS abutment consists of a custom titanium metal insert and zirconia coping in which the access hole is located in an esthetic position with an ASC system. The SS abutment results in a crown with more normal crown dimensions that also provides more space for the soft tissues. This SS abutment design allows clinicians to obtain screw-retained restorations with optimal esthetics and mechanical strength. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Benchmarking the FCI at Illinois State's Residential Life.

ERIC Educational Resources Information Center

Cain, David A.

1998-01-01

Describes how Office of Residential Life at one university met maintenance challenges facing its residential and food-service facilities. Discusses study conducted in 1992 to evaluate widespread management practices and addresses its findings, including six recommended practices. Examines development and implementation of facilities audit,…

The role of optical sensors in environmental applications

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

Coulter, S.L.; Klainer, S.M.; Saini, D.

1995-12-31

With the ever increasing regulations and public consciousness on pollution control there is an increasing demand for effective monitors for field use. The specifications for an effective field monitor are that it be an in situ sensor which presents real time data; that data are received without sampling or testing artifacts; and, that there is a low cost associated with running multiple tests. Fiber optic chemical sensors have been designed by FCI Environmental, Inc. which meet these specifications for the detection of hydrocarbons in air, water or soil. Recent developments at FCI Environmental in the field of optic chemical sensorsmore » include the development of a chip level waveguide sensor. With the improvements in the size and function of the sensor, which impacts the manufacturability and cost of the sensors, this new technology presents new opportunities in the fields of in situ monitoring. Current activities in the development of this technology and applications of specific solid-state immunoassay are discussed.« less

Evidence on the coherence-pieces debate from the force concept inventory

NASA Astrophysics Data System (ADS)

Badagnani, D.; Petrucci, D.; Cappannini, O.

2018-01-01

We use force concept inventory (FCI) data to probe the consistency of commonsense physics as a knowledge system. The source of this data is the administration of the FCI to first-year science university students. Data quality was checked using item response theory and studying answer distributions for each question. We find apparently paradoxical results: depending on how the data is analysed, answers seem highly systematic or almost random-like. These results are compatible with others found in the literature and can be construed as arising either from a coherent knowledge system or from knowledge in pieces. We hypothesise as a possible source of this apparent contradiction that predictions and explanations use different resources: the former would use reflex, low-cost cognitive resources while the latter would involve conceptualisations. We show that the articulation of both resources may be crucial for expert thinking productivity (the ability to apply a theory to novel situations). We sketch some consequences of the proposed structure of commonsense thinking for teaching and further research.

Analysis of Newton's Third Law Questions on the Force Concepts Inventory at Georgia State University

NASA Astrophysics Data System (ADS)

Oakley, Christopher; Thoms, Brian

2012-03-01

A major emphasis of the Physics Education Research program at Georgia State University is an effort to assess and improve students' understanding of Newton's Laws concepts. As part of these efforts the Force Concepts Inventory (FCI) has been given to students in both the algebra-based and calculus-based introductory physics sequences. In addition, the algebra-based introductory physics sequence is taught in both a SCALE-UP and a traditional lecture format. The results of the FCI have been analyzed by individual question and also as categorized by content. The analysis indicates that students in both algebra and calculus-based courses are successful at overcoming Aristotelian misconceptions regarding Newton's Third Law (N3) in the context of a stationary system. However, students are less successful on N3 questions involving objects in constant motion or accelerating. Interference between understanding of Newton's Second and Third Laws as well as other possible explanations for lower student performance on N3 questions involving non-stationary objects will be discussed.

4 channel × 10 Gb/s bidirectional optical subassembly using silicon optical bench with precise passive optical alignment.

PubMed

Kang, Eun Kyu; Lee, Yong Woo; Ravindran, Sooraj; Lee, Jun Ki; Choi, Hee Ju; Ju, Gun Wu; Min, Jung Wook; Song, Young Min; Sohn, Ik-Bu; Lee, Yong Tak

2016-05-16

We demonstrate an advanced structure for optical interconnect consisting of 4 channel × 10 Gb/s bidirectional optical subassembly (BOSA) formed using silicon optical bench (SiOB) with tapered fiber guiding holes (TFGHs) for precise and passive optical alignment of vertical-cavity surface-emitting laser (VCSEL)-to-multi mode fiber (MMF) and MMF-to-photodiode (PD). The co-planar waveguide (CPW) transmission line (Tline) was formed on the backside of silicon substrate to reduce the insertion loss of electrical data signal. The 4 channel VCSEL and PD array are attached at the end of CPW Tline using a flip-chip bonder and solder pad. The 12-channel ribbon fiber is simply inserted into the TFGHs of SiOB and is passively aligned to the VCSEL and PD in which no additional coupling optics are required. The fabricated BOSA shows high coupling efficiency and good performance with the clearly open eye patterns and a very low bit error rate of less than 10^-12 order at a data rate of 10 Gb/s with a PRBS pattern of 2³¹-1.

Prototype positron emission tomography insert with electro-optical signal transmission for simultaneous operation with MRI.

PubMed

Olcott, Peter; Kim, Ealgoo; Hong, Keyjo; Lee, Brian J; Grant, Alexander M; Chang, Chen-Ming; Glover, Gary; Levin, Craig S

2015-05-07

The simultaneous acquisition of PET and MRI data shows promise to provide powerful capabilities to study disease processes in human subjects, guide the development of novel treatments, and monitor therapy response and disease progression. A brain-size PET detector ring insert for an MRI system is being developed that, if successful, can be inserted into any existing MRI system to enable simultaneous PET and MRI images of the brain to be acquired without mutual interference. The PET insert uses electro-optical coupling to relay all the signals from the PET detectors out of the MRI system using analog modulated lasers coupled to fiber optics. Because the fibers use light instead of electrical signals, the PET detector can be electrically decoupled from the MRI making it partially transmissive to the RF field of the MRI. The SiPM devices and low power lasers were powered using non-magnetic MRI compatible batteries. Also, the number of laser-fiber channels in the system was reduced using techniques adapted from the field of compressed sensing. Using the fact that incoming PET data is sparse in time and space, electronic circuits implementing constant weight codes uniquely encode the detector signals in order to reduce the number of electro-optical readout channels by 8-fold. Two out of a total of sixteen electro-optical detector modules have been built and tested with the entire RF-shielded detector gantry for the PET ring insert. The two detectors have been tested outside and inside of a 3T MRI system to study mutual interference effects and simultaneous performance with MRI. Preliminary results show that the PET insert is feasible for high resolution simultaneous PET/MRI imaging for applications in the brain.

Prototype positron emission tomography insert with electro-optical signal transmission for simultaneous operation with MRI

NASA Astrophysics Data System (ADS)

Olcott, Peter; Kim, Ealgoo; Hong, Keyjo; Lee, Brian J.; Grant, Alexander M.; Chang, Chen-Ming; Glover, Gary; Levin, Craig S.

2015-05-01

The simultaneous acquisition of PET and MRI data shows promise to provide powerful capabilities to study disease processes in human subjects, guide the development of novel treatments, and monitor therapy response and disease progression. A brain-size PET detector ring insert for an MRI system is being developed that, if successful, can be inserted into any existing MRI system to enable simultaneous PET and MRI images of the brain to be acquired without mutual interference. The PET insert uses electro-optical coupling to relay all the signals from the PET detectors out of the MRI system using analog modulated lasers coupled to fiber optics. Because the fibers use light instead of electrical signals, the PET detector can be electrically decoupled from the MRI making it partially transmissive to the RF field of the MRI. The SiPM devices and low power lasers were powered using non-magnetic MRI compatible batteries. Also, the number of laser-fiber channels in the system was reduced using techniques adapted from the field of compressed sensing. Using the fact that incoming PET data is sparse in time and space, electronic circuits implementing constant weight codes uniquely encode the detector signals in order to reduce the number of electro-optical readout channels by 8-fold. Two out of a total of sixteen electro-optical detector modules have been built and tested with the entire RF-shielded detector gantry for the PET ring insert. The two detectors have been tested outside and inside of a 3T MRI system to study mutual interference effects and simultaneous performance with MRI. Preliminary results show that the PET insert is feasible for high resolution simultaneous PET/MRI imaging for applications in the brain.

Cookbook Procedures in MBL Physics Exercises.

ERIC Educational Resources Information Center

Royuk, Brent; Brooks, David W.

2003-01-01

Presents results of a controlled experiment comparing the conceptual mechanics learning gains as measured by the Force Concept Inventory (FCI) between two laboratory groups. One group completed cookbook labs while the other completed Interactive-Engagement (IE) labs in RealTime Physics. Suggests that laboratory activities should engage students in…

Condition of Florida Educational Facilities and Balancing Budgets

ERIC Educational Resources Information Center

Jones, Margaret Moore

2012-01-01

The purpose of this study was to examine if relationships existed between the condition of instructional facilities within Florida Coastal School District, as measured by the Facilities Condition Index (FCI), and enrollment percentages for special education students, African American students, Caucasian students, and students receiving free and…

Effects of increasing the allowable compressive stress at release on the shear strength of prestressed concrete girders.

DOT National Transportation Integrated Search

2008-09-01

In recent years, several research projects have been conducted to study the feasibility of increasing the allowable : compressive stress in concrete at prestress transfer, currently defined as 0.60f'ci in the AASHTO LRFD Bridge : Design Specification...

NPDES Permit for Federal Corrections Institution, Englewood Municipal Separate Storm Sewer System in Colorado

EPA Pesticide Factsheets

Under NPDES permit CO-R042005, the Federal Corrections Institution (FCI), Englewood is authorized to discharge from all MS4 outfalls to receiving waters which include Bear Creek, the South Platte River in the City of Lakewood, Jefferson County, Colo.

Tire deflation device

DOEpatents

Barker, Stacey G [Idaho Falls, ID

2010-01-05

A tire deflation device includes (1) a component having a plurality of bores, (2) a plurality of spikes removably insertable into the plurality of bores and (3) a keeper within each among the plurality of bores, the keeper being configured to contact a sidewall surface of a spike among the plurality of spikes and to exert force upon the sidewall surface. In an embodiment, the tire deflation device includes (a) a component including a bore in a material, the bore including a receiving region, a sidewall surface and a base surface, (b) a channel extending from the sidewall surface into the material, (c) a keeper having a first section housed within the channel and a second section which extends past the sidewall surface into the receiving region, and (d) a spike removably insertable into the bore.

Structure of Carbon Nanotube Porins in Lipid Bilayers: An in Situ Small-Angle X-ray Scattering (SAXS) Study [Atomic-level structure of carbon nanotube porins in lipid bilayers: an in-situ small-angle x-ray scattering (SAXS) study

DOE PAGES

Tran, Ich C.; Tunuguntla, Ramya H.; Kim, Kyunghoon; ...

2016-06-20

Carbon nanotube porins (CNTPs), small segments of carbon nanotubes capable of forming defined pores in lipid membranes, are important future components for bionanoelectronic devices as they could provide a robust analog of biological membrane channels. Furthermore, in order to control the incorporation of these CNT channels into lipid bilayers, it is important to understand the structure of the CNTPs before and after insertion into the lipid bilayer as well as the impact of such insertion on the bilayer structure. Here we employed a noninvasive in situ probe, small-angle X-ray scattering, to study the integration of CNT porins into dioleoylphosphatidylcholine bilayers.more » These results show that CNTPs in solution are stabilized by a monolayer of lipid molecules wrapped around their outer surface. We also demonstrate that insertion of CNTPs into the lipid bilayer results in decreased bilayer thickness with the magnitude of this effect increasing with the concentration of CNTPs.« less

Decrypting protein insertion through the translocon with free-energy calculations.

PubMed

Gumbart, James C; Chipot, Christophe

2016-07-01

Protein insertion into a membrane is a complex process involving numerous players. The most prominent of these players is the Sec translocon complex, a conserved protein-conducting channel present in the cytoplasmic membrane of bacteria and the membrane of the endoplasmic reticulum in eukaryotes. The last decade has seen tremendous leaps forward in our understanding of how insertion is managed by the translocon and its partners, coming from atomic-detailed structures, innovative experiments, and well-designed simulations. In this review, we discuss how experiments and simulations, hand-in-hand, teased out the secrets of the translocon-facilitated membrane insertion process. In particular, we focus on the role of free-energy calculations in elucidating membrane insertion. Amazingly, despite all its apparent complexity, protein insertion into membranes is primarily driven by simple thermodynamic and kinetic principles. This article is part of a Special Issue entitled: Membrane proteins edited by J.C. Gumbart and Sergei Noskov. Copyright © 2016 Elsevier B.V. All rights reserved.

Intelligent vision guide for automatic ventilation grommet insertion into the tympanic membrane.

PubMed

Gao, Wenchao; Tan, Kok Kiong; Liang, Wenyu; Gan, Chee Wee; Lim, Hsueh Yee

2016-03-01

Otitis media with effusion is a worldwide ear disease. The current treatment is to surgically insert a ventilation grommet into the tympanic membrane. A robotic device allowing automatic grommet insertion has been designed in a previous study; however, the part of the membrane where the malleus bone is attached to the inner surface is to be avoided during the insertion process. This paper proposes a synergy of optical flow technique and a gradient vector flow active contours algorithm to achieve an online tracking of the malleus under endoscopic vision, to guide the working channel to move efficiently during the surgery. The proposed method shows a more stable and accurate tracking performance than the current tracking methods in preclinical tests. With satisfactory tracking results, vision guidance of a suitable insertion spot can be provided to the device to perform the surgery in an automatic way. Copyright © 2015 John Wiley & Sons, Ltd.

Tutorials in Introductory Physics: The Pain and the Gain

ERIC Educational Resources Information Center

Cruz, Emerson; O'Shea, Brian; Schaffenberger, Werner; Wolf, Steven; Kortemeyer, Gerd

2010-01-01

In an introductory physics sequence with a large enrollment of premedical students, traditional recitation sessions were replaced by "Tutorials in Introductory Physics," developed by the Physics Education Group at the University of Washington. Initially, summative test scores (as well as FCI scores) dramatically increased, but so did…

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Assessing Conceptual Knowledge for the Physics of Semiconductors

ERIC Educational Resources Information Center

Ene, Emanuela

2013-01-01

Following the trend in science and engineering education generated by the visible impact created by the Force Concept Inventory (FCI), the investigator developed a Physics of Semiconductors Concept Inventory (PSCI). PSCI fills the need of standardized concept tests for undergraduate education in photonics and electrical engineering. The structure…

Mass-flow-rate-controlled fluid flow in nanochannels by particle insertion and deletion.

PubMed

Barclay, Paul L; Lukes, Jennifer R

2016-12-01

A nonequilibrium molecular dynamics method to induce fluid flow in nanochannels, the insertion-deletion method (IDM), is introduced. IDM inserts and deletes particles within distinct regions in the domain, creating locally high and low pressures. The benefits of IDM are that it directly controls a physically meaningful quantity, the mass flow rate, allows for pressure and density gradients to develop in the direction of flow, and permits treatment of complex aperiodic geometries. Validation of IDM is performed, yielding good agreement with the analytical solution of Poiseuille flow in a planar channel. Comparison of IDM to existing methods indicates that it is best suited for gases, both because it intrinsically accounts for compressibility effects on the flow and because the computational cost of particle insertion is lowest for low-density fluids.

Lithiation Thermodynamics and Kinetics of the TiO 2 (B) Nanoparticles

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

Hua, Xiao; Liu, Zheng; Fischer, Michael G.

TiO2 (B) has attracted a lot of attention in recent years because it exhibits the largest capacity among all studied titania polymorphs with high rate performance for Li intercalation achieved when this material is nanostructured. However, due to the complex nature of its lithiation mechanism and practical challenges in probing Li local environments in nanostructured materials, a definitive understanding of the lithiation thermodynamics has yet to be established. A comprehensive mechanistic investigation of the TiO2 (B) nanoparticles is therefore presented using a combination of in situ / operando X-ray pair distribution function (PDF) and electrochemical techniques. The discharge begins withmore » surface reactions involving surface hydroxyl groups. Such reactions contribute to the capacity loss and take place in parallel with Li insertion into the near-surface region of the nanoparticles. The Li bulk insertion starts with a single-phase reaction into the A2 site, a position adjacent to the b channel. A change of the Li diffusion pathway from that along this open channel to that along the c-direction is likely to occur at the composition of Li0.25TiO2 until Li0.5TiO2 is attained, leading to a two-step A2-site incorporation with one step kinetically distinct from the other. Subsequent Li insertion involves C’ site, a position situated inside the channel, and follows a rapid two-phase reaction to form Li0.75TiO2. Due to the high diffusion barrier associated with the further lithiation, Li insertion into the A1 site, another position adjacent to the channel neighboring the A2 sites, is kinetically restricted. It can be promoted by either nanostructuring or raising the operating temperature, the latter however triggering concurrent electrolyte decomposition giving rise to additional capacity loss. This study not only provides compelling experimental evidence for the unresolved reaction thermodynamics of nanoparticulate TiO2 (B), but also serves as a strong reference for future studies of the bulk phase, and for future calculations to study the kinetic properties of TiO2 (B).« less

Low jitter, low inductance solid dielectric switches.

PubMed

Guenther, A H; Strickland, D M; Bettis, J R

1979-11-01

It has been shown that the use of graded solid dielectric sandwiches in laser-triggered spark gaps (LTS) can lead to highly desirable multichannel operations while maintaining the low delay and jitter performance characteristics of LTS. As many as ten separate breakdown channels were observed when small circular or hexagonal aluminum inserts were inserted between two Mylar dielectric sheets stressed at 4.1 kV/mil. A reduction in rise time was noted for these multichannel switching events.

Membrane-Based Functions in the Origin of Cellular Life

NASA Technical Reports Server (NTRS)

Wilson, Michael A.

2003-01-01

How simple membrane peptides performed such essential proto-cellular functions as transport of ions and organic matter across membranes separating the interior of the cell from the environment, capture and utilization of energy, and transduction of environmental signals, is a key question in protobiological evolution. On the basis of detailed, molecular-level computer simulations we investigate how these peptides insert into membranes, self-assemble into higher-order structures and acquire functions. We have studied the insertion of an a-helical peptide containing leucine (L) and serine (S) of the form (LSLLLSL)S into a model membrane. The transmembrane state is metastable, and approximately 15 kcal/mol is required to insert the peptide into the membrane. Investigations of dimers formed by (LSLLLSL)S and glycophorin A demonstrate how the favorable free energy of helix association can offset the unfavorable free energy of insertion, leading to self- assembly of peptide helices in the membrane. An example of a self-assembled structure is the tetrameric transmembrane pore of the influenza virus M2 protein, which is an efficient and selective voltage-gated proton channel. Our simulations explain the gating mechanism and provide guidelines how to reengineering the channel to act as a simple proton pump. In general, emergence of integral membrane proteins appears to be quite feasible and may be easier to envision than the emergence of water-soluble proteins.

Genome-wide screening identifies a KCNIP1 copy number variant as a genetic predictor for atrial fibrillation

PubMed Central

Tsai, Chia-Ti; Hsieh, Chia-Shan; Chang, Sheng-Nan; Chuang, Eric Y.; Ueng, Kwo-Chang; Tsai, Chin-Feng; Lin, Tsung-Hsien; Wu, Cho-Kai; Lee, Jen-Kuang; Lin, Lian-Yu; Wang, Yi-Chih; Yu, Chih-Chieh; Lai, Ling-Ping; Tseng, Chuen-Den; Hwang, Juey-Jen; Chiang, Fu-Tien; Lin, Jiunn-Lee

2016-01-01

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Previous genome-wide association studies had identified single-nucleotide polymorphisms in several genomic regions to be associated with AF. In human genome, copy number variations (CNVs) are known to contribute to disease susceptibility. Using a genome-wide multistage approach to identify AF susceptibility CNVs, we here show a common 4,470-bp diallelic CNV in the first intron of potassium interacting channel 1 gene (KCNIP1) is strongly associated with AF in Taiwanese populations (odds ratio=2.27 for insertion allele; P=6.23 × 10−24). KCNIP1 insertion is associated with higher KCNIP1 mRNA expression. KCNIP1-encoded protein potassium interacting channel 1 (KCHIP1) is physically associated with potassium Kv channels and modulates atrial transient outward current in cardiac myocytes. Overexpression of KCNIP1 results in inducible AF in zebrafish. In conclusions, a common CNV in KCNIP1 gene is a genetic predictor of AF risk possibly pointing to a functional pathway. PMID:26831368

Study on airflow characteristics in the semi-closed irregular narrow flow channel

NASA Astrophysics Data System (ADS)

Jin, Yuzhen; Hu, Xiaodong; Zhu, Linhang; Hu, Xudong; Jin, Yingzi

2016-04-01

The air-jet loom is widely used in the textile industry. The interaction mechanism of airflow and yarn is not clear in such a narrow flow channel, the gas consumption is relatively large, the yarn motion is unstable and the weft insertion is often interrupted during the operation. In order to study the characteristics of the semi-closed flow field in profiled dents, the momentum conservation equation is modified and the model parameters and boundary conditions are set. Compared with the different r, the ratio of profiled dent's thickness and gap, the results show that the smaller the r is, the smaller the velocity fluctuations of the airflow is. When the angle of profiled dents α is close to zero, the diffusion of the airflow will be less. The experiment is also conducted to verify the result of the simulation with a high-speed camera and pressure sensor in profiled dents. The airflow characteristics in the semi-closed irregular narrow flow channel in the paper would provide the theoretical basis for optimizing the weft insertion process of the air-jet loom.

Characterization of a purine permease family gene OsPUP7 involved in growth and development control in rice.

PubMed

Qi, Zhuyun; Xiong, Lizhong

2013-11-01

In this study, PUP-type cytokinin transporter genes were identified in rice (Oryza sativa L.). The Oryza sativa purine permease (OsPUP) family has 12 members that show similar predicted protein sequences with AtPUPs. To reveal the functions of OsPUP genes, we searched the T-DNA mutant library of rice and found one mutant for the member OsPUP7. The T-DNA insertion caused a new transcript that encodes a protein with 26 amino acids different from the native OsPUP7 at the C-terminus. The mutant showed multiple phenotypic changes including increased plant height, big seeds, and delayed flowering. The mutant also showed increased sensitivity to drought and salt stresses and treatments with kinetin and abscisic acid. OsPUP7 is expressed mainly in the vascular bundle, pistil, and stamens. The measurement of cytokinins (CKs) showed that CK content in the mutant spikelets accumulated higher than that in the wild type. Moreover, uptake experiment in the yeast fcy2 mutant suggested that OsPUP7 has the ability to transport caffeine, a CK derivative. Our results indicate that the PUP transport system also exists in rice, and OsPUP7 has an important role in the transport of CK, thus affecting developmental process and stress responses. © 2013 Institute of Botany, Chinese Academy of Sciences.

Tunable dual-channel filter based on the photonic crystal with air defects.

PubMed

Zhao, Xiaodan; Yang, Yibiao; Wen, Jianhua; Chen, Zhihui; Zhang, Mingda; Fei, Hongming; Hao, Yuying

2017-07-01

We propose a tuning filter containing two channels by inserting a defect layer (Air/Si/Air/Si/Air) into a one-dimensional photonic crystal of Si/SiO 2 , which is on the symmetry of the defect. Two transmission peaks (1528.98 and 1564.74 nm) appear in the optical communication S-band and C-band, and the transmittance of these two channels is up to 100%. In addition, this design realizes multi-channel filtering to process large dynamic range or multiple independent signals in the near-infrared band by changing the structure. The tuning range will be enlarged, and the channels can be moved in this range through the easy control of air thickness and incident angle.

Intelligent switches of integrated lightwave circuits with core telecommunication functions

NASA Astrophysics Data System (ADS)

Izhaky, Nahum; Duer, Reuven; Berns, Neil; Tal, Eran; Vinikman, Shirly; Schoenwald, Jeffrey S.; Shani, Yosi

2001-05-01

We present a brief overview of a promising switching technology based on Silica on Silicon thermo-optic integrated circuits. This is basically a 2D solid-state optical device capable of non-blocking switching operation. Except of its excellent performance (insertion loss<5dB, switching time<2ms...), the switch enables additional important build-in functionalities. It enables single-to- single channel switching and single-to-multiple channel multicasting/broadcasting. In addition, it has the capability of channel weighting and variable output power control (attenuation), for instance, to equalize signal levels and compensate for unbalanced different optical input powers, or to equalize unbalanced EDFA gain curve. We examine the market segments appropriate for the switch size and technology, followed by a discussion of the basic features of the technology. The discussion is focused on important requirements from the switch and the technology (e.g., insertion loss, power consumption, channel isolation, extinction ratio, switching time, and heat dissipation). The mechanical design is also considered. It must take into account integration of optical fiber, optical planar wafer, analog electronics and digital microprocessor controls, embedded software, and heating power dissipation. The Lynx Photon.8x8 switch is compared to competing technologies, in terms of typical market performance requirements.

Characterization of a novel 132-bp exon of the human maxi-K channel.

PubMed

Korovkina, V P; Fergus, D J; Holdiman, A J; England, S K

2001-07-01

The large-conductance Ca2+-activated voltage-dependent K+ channel (maxi-K channel) induces a significant repolarizing current that buffers cell excitability. This channel can derive its diversity by alternative splicing of its transcript-producing isoforms that differ in their sensitivity to voltage and intracellular Ca2+. We have identified a novel 132-bp exon of the maxi-K channel from human myometrial cells that encodes 44 amino acids within the first intracellular loop of the channel protein. Distribution analysis reveals that this exon is expressed predominantly in human smooth muscle tissues with the highest abundance in the uterus and aorta and resembles the previously reported distribution of the total maxi-K channel transcript. Single-channel K+ current measurements in fibroblasts transfected with the maxi-K channel containing this novel 132-bp exon demonstrate that the presence of this insert attenuates the sensitivity to voltage and intracellular Ca2+. Alternative splicing to introduce this 132-bp exon into the maxi-K channel may elicit another mode to modulate cell excitability.

The NH2 terminus regulates voltage-dependent gating of CALHM ion channels.

PubMed

Tanis, Jessica E; Ma, Zhongming; Foskett, J Kevin

2017-08-01

Calcium homeostasis modulator protein-1 (CALHM1) and its Caenorhabditis elegans (ce) homolog, CLHM-1, belong to a new family of physiologically important ion channels that are regulated by voltage and extracellular Ca 2+ (Ca 2+ o ) but lack a canonical voltage-sensing domain. Consequently, the intrinsic voltage-dependent gating mechanisms for CALHM channels are unknown. Here, we performed voltage-clamp experiments on ceCLHM-1 chimeric, deletion, insertion, and point mutants to assess the role of the NH 2 terminus (NT) in CALHM channel gating. Analyses of chimeric channels in which the ceCLHM-1 and human (h)CALHM1 NH 2 termini were interchanged showed that the hCALHM1 NT destabilized channel-closed states, whereas the ceCLHM-1 NT had a stabilizing effect. In the absence of Ca 2+ o , deletion of up to eight amino acids from the ceCLHM-1 NT caused a hyperpolarizing shift in the conductance-voltage relationship with little effect on voltage-dependent slope. However, deletion of nine or more amino acids decreased voltage dependence and induced a residual conductance at hyperpolarized voltages. Insertion of amino acids into the NH 2 -terminal helix also decreased voltage dependence but did not prevent channel closure. Mutation of ceCLHM-1 valine 9 and glutamine 13 altered half-maximal activation and voltage dependence, respectively, in 0 Ca 2+ In 2 mM Ca 2+ o , ceCLHM-1 NH 2 -terminal deletion and point mutant channels closed completely at hyperpolarized voltages with apparent affinity for Ca 2+ o indistinguishable from wild-type ceCLHM-1, although the ceCLHM-1 valine 9 mutant exhibited an altered conductance-voltage relationship and kinetics. We conclude that the NT plays critical roles modulating voltage dependence and stabilizing the closed states of CALHM channels. Copyright © 2017 the American Physiological Society.

Rasch Model Based Analysis of the Force Concept Inventory

ERIC Educational Resources Information Center

Planinic, Maja; Ivanjek, Lana; Susac, Ana

2010-01-01

The Force Concept Inventory (FCI) is an important diagnostic instrument which is widely used in the field of physics education research. It is therefore very important to evaluate and monitor its functioning using different tools for statistical analysis. One of such tools is the stochastic Rasch model, which enables construction of linear…

Uncovering the Hidden Meaning of Cross-Curriculum Comparison Results on the Force Concept Inventory

ERIC Educational Resources Information Center

Ding, Lin; Caballero, Marcos D.

2014-01-01

In a recent study, Caballero and colleagues conducted a large-scale evaluation using the Force Concept Inventory (FCI) to compare student learning outcomes between two introductory physics curricula: the Matter and Interactions (M&I) mechanics course and a pedagogically-reformed-traditional-content (PRTC) mechanics course. Using a conventional…

Force Concept Inventory-Based Multiple-Choice Test for Investigating Students' Representational Consistency

ERIC Educational Resources Information Center

Nieminen, Pasi; Savinainen, Antti; Viiri, Jouni

2010-01-01

This study investigates students' ability to interpret multiple representations consistently (i.e., representational consistency) in the context of the force concept. For this purpose we developed the Representational Variant of the Force Concept Inventory (R-FCI), which makes use of nine items from the 1995 version of the Force Concept Inventory…

Students' Proficiency Scores within Multitrait Item Response Theory

ERIC Educational Resources Information Center

Scott, Terry F.; Schumayer, Daniel

2015-01-01

In this paper we present a series of item response models of data collected using the Force Concept Inventory. The Force Concept Inventory (FCI) was designed to poll the Newtonian conception of force viewed as a multidimensional concept, that is, as a complex of distinguishable conceptual dimensions. Several previous studies have developed…

High performance equipped mirrors for MTG FCI-TA and IRS-FTO

NASA Astrophysics Data System (ADS)

Kazakov, T.; San Juan, J. L.; Serrano, J.; Moreno, J.; González, D.; Rodríguez, G.; López, D.; Vázquez, E.; Aivar, J.; Motos, A.; Rahmouni, Christophe; Imperiali, Stephan; Fappani, Denis

2017-09-01

The Meteosat Third Generation (MTG) Programme is being realised through the well established and successful Cooperation between EUMETSAT and ESA. It will ensure the future continuity of MSG with the capabilities to enhance nowcasting, global and regional numerical weather prediction, climate and atmospheric chemistry monitoring data from Geostationary Orbit.

Polarization of Physics on Global Courses

ERIC Educational Resources Information Center

Alinea, Allan L.; Naylor, Wade

2015-01-01

Since October 2010, the Chemistry-Biology Combined Major Program, an international course taught in English at Osaka University, has been teaching small classes (no more than 20 in size). We present data from the Force Concept Inventory (FCI) given to first-year classical mechanics students (N = 47 students over three years) pre and post score,…

NIF Rugby High Foot Campaign from the design side

NASA Astrophysics Data System (ADS)

Leidinger, J.-P.; Callahan, D. A.; Berzak-Hopkins, L. F.; Ralph, J. E.; Amendt, P.; Hinkel, D. E.; Michel, P.; Moody, J. D.; Ross, J. S.; Rygg, J. R.; Celliers, P.; Clouët, J.-F.; Dewald, E. L.; Kaiser, P.; Khan, S.; Kritcher, A. L.; Liberatore, S.; Marion, D.; Masson-Laborde, P.-E.; Milovich, J. L.; Morice, O.; Pak, A. E.; Poujade, O.; Strozzi, D.; Hurricane, O. A.

2016-05-01

The NIF Rugby High Foot campaign results, with 8 shots to date, are compared with the 2D FCI2 design simulations. A special emphasis is placed on the predictive features and on those areas where some work is still required to achieve the best possible modelling of these MJ-class experiments.

Finding Frequent Closed Itemsets in Sliding Window in Linear Time

NASA Astrophysics Data System (ADS)

Chen, Junbo; Zhou, Bo; Chen, Lu; Wang, Xinyu; Ding, Yiqun

One of the most well-studied problems in data mining is computing the collection of frequent itemsets in large transactional databases. Since the introduction of the famous Apriori algorithm [14], many others have been proposed to find the frequent itemsets. Among such algorithms, the approach of mining closed itemsets has raised much interest in data mining community. The algorithms taking this approach include TITANIC [8], CLOSET+[6], DCI-Closed [4], FCI-Stream [3], GC-Tree [15], TGC-Tree [16] etc. Among these algorithms, FCI-Stream, GC-Tree and TGC-Tree are online algorithms work under sliding window environments. By the performance evaluation in [16], GC-Tree [15] is the fastest one. In this paper, an improved algorithm based on GC-Tree is proposed, the computational complexity of which is proved to be a linear combination of the average transaction size and the average closed itemset size. The algorithm is based on the essential theorem presented in Sect. 4.2. Empirically, the new algorithm is several orders of magnitude faster than the state of art algorithm, GC-Tree.

Assessing the Impacts of a Hybrid ``Flipped'' Approach to University Physics.

NASA Astrophysics Data System (ADS)

Hughes, Chris; Paulson, Scott

2015-03-01

Over the course of several years, the physics faculty at James Madison University has been gradually reforming the introductory calculus-based physics sequence to a hybrid model using a ``flipped classroom'' approach. The content traditionally delivered during lecture was divided into approximately 150 short (5-10 minute) videos. For homework, students are assigned 3-5 videos to watch before each class session. These assignments are combined with in-class activities including gouger problem solving and the tutorials developed by the University of Washington group to provide the students with focused guidance on concepts and skills that students traditionally have left our classes not having mastered. For the fall semester course on mechanics, the Force Concept Inventory (FCI) was used to evaluate student outcomes. For the spring semester course on E&M and optics, the Conceptual Survey of Electricity and Magnetism (CSEM) was used. Student reaction to the course structure was generally positive though there were some complaints in the student evaluations at the end of each semester. However, a positive impact on student outcomes was observed based on the Hake gains on the FCI.

Financial capacity in dementia: a systematic review.

PubMed

Sudo, Felipe Kenji; Laks, Jerson

2017-07-01

Financial capacity (FC) refers to a set of cognitively mediated abilities related to one's competency to manage propriety and income. Identifying intact from impaired FC in older persons with dementia is a growing concern in geriatric practice, but the best methods to assess this function still need to be determined. This study aims to review data on FC in dementia and on instruments used to assess this domain of capacity. Database search was performed in Medline, ISI Web of Knowledge, LILACS and PsycINFO. Studies that objectively assessed FC in dementia of any etiology were included. Of a total of 125 articles, 10 were included. Mild Alzheimer's Disease (AD) was associated with impaired complex FC abilities, namely checkbook management, bank statement management and financial judgment, but simple FC skills were preserved. Moderate AD was associated with impairment in all domains of FC. The Financial Capacity Instrument (FCI) was applied in most of the selected studies and correlated with neuropsychological and neuroimaging variables. Early dementia is associated with partially preserved FC. More validation studies using objective and evidence-based FC assessment tools, such as the FCI, are still needed.

Moving toward change: Institutionalizing reform through implementation of the Learning Assistant model and Open Source Tutorials

NASA Astrophysics Data System (ADS)

Goertzen, Renee Michelle; Brewe, Eric; Kramer, Laird H.; Wells, Leanne; Jones, David

2011-12-01

Florida International University has undergone a reform in the introductory physics classes by focusing on the laboratory component of these classes. We present results from the secondary implementation of two research-based instructional strategies: the implementation of the Learning Assistant model as developed by the University of Colorado at Boulder and the Open Source Tutorial curriculum developed at the University of Maryland, College Park. We examine the results of the Force Concept Inventory (FCI) for introductory students over five years (n=872) and find that the mean raw gain of students in transformed lab sections was 0.243, while the mean raw gain of the traditional labs was 0.159, with a Cohen’s d effect size of 0.59. Average raw gains on the FCI were 0.243 for Hispanic students and 0.213 for women in the transformed labs, indicating that these reforms are not widening the gaps between underrepresented student groups and majority groups. Our results illustrate how research-based instructional strategies can be successfully implemented in a physics department with minimal department engagement and in a sustainable manner.

Image Reconstruction from Data Collected with an Imaging Interferometer

NASA Astrophysics Data System (ADS)

DeSantis, Z. J.; Thurman, S. T.; Hix, T. T.; Ogden, C. E.

The intensity distribution of an incoherent source and the spatial coherence function at some distance away are related by a Fourier transform, via the Van Cittert-Zernike theorem. Imaging interferometers measure the spatial coherence of light propagated from the incoherently illuminated object by combining light from spatially separated points to measure interference fringes. The contrast and phase of the fringe are the amplitude and phase of a Fourier component of the source’s intensity distribution. The Fiber-Coupled Interferometer (FCI) testbed is a visible light, lab-based imaging interferometer designed to test aspects of an envisioned ground-based interferometer for imaging geosynchronous satellites. The front half of the FCI testbed consists of the scene projection optics, which includes an incoherently backlit scene, located at the focus of a 1 m aperture f/100 telescope. The projected light was collected by the back half of the FCI testbed. The collection optics consisted of three 11 mm aperture fiber-coupled telescopes. Light in the fibers was combined pairwise and dispersed onto a sensor to measure the interference fringe as a function of wavelength, which produces a radial spoke of measurements in the Fourier domain. The visibility function was sampled throughout the Fourier domain by recording fringe data at many different scene rotations and collection telescope separations. Our image reconstruction algorithm successfully produced images for the three scenes we tested: asymmetric pair of pinholes, U.S. Air Force resolution bar target, and satellite scene. The bar target reconstruction shows detail and resolution near the predicted resolution limit. This research was developed with funding from the Defense Advanced Research Projects Agency (DARPA). The views, opinions and/or findings expressed are those of the author(s) and should not be interpreted as reflecting the official views or policies of the Department of Defense or the U.S. Government.

Quantum Algorithms for Scientific Computing and Approximate Optimization

NASA Astrophysics Data System (ADS)

Hadfield, Stuart Andrew

Diversity and inclusion has been a concern for the physics community for nearly 50 years. Despite significant efforts including the American Physical Society (APS) Conferences for Undergraduate Women in Physics (CUWiP) and the APS Bridge Program, women, African Americans, and Hispanics continue to be substantially underrepresented in the physics profession. Similar efforts within the field of engineering, whose students make up the majority of students in the introductory calculus-based physics courses, have also met with limited success. With the introduction of research-based instruments such as the Force Concept Inventory (FCI), the Force and Motion Conceptual Evaluation (FMCE), and the Conceptual Survey of Electricity and Magnetism (CSEM), differences in performance by gender began to be reported. Researchers have yet to come to an agreement as to why these "gender gaps" exist in the conceptual inventories that are widely used in physics education research and/or how to reduce the gaps. The "gender gap" has been extensively studied; on average, for the mechanics conceptual inventories, male students outperform female students by 13% on the pretest and by 12% post instruction. While much of the gender gap research has been geared toward the mechanics conceptual inventories, there have been few studies exploring the gender gap in the electricity and magnetism conceptual inventories. Overall, male students outperform female students by 3.7% on the pretest and 8.5% on the post-test; however, these studies have much more variation including one study showing female students outperforming male students on the CSEM. Many factors have been proposed that may influence the gender gap, from differences in background and preparation to various psychological and sociocultural effects. A parallel but largely disconnected set of research has identified gender biased questions within the FCI. This research has produced sporadic results and has only been performed on the FCI. The work performed in this manuscript will seek to synthesize these strands and use large datasets and deep demographic data to understand the persistent differences in male and female performance.

Learning physics concepts as a function of colloquial language usage

NASA Astrophysics Data System (ADS)

Maier, Steven J.

Data from two sections of college introductory, algebra-based physics courses (n1 = 139, n2 = 91) were collected using three separate instruments to investigate the relationships between reasoning ability, conceptual gain and colloquial language usage. To obtain a measure of reasoning ability, Lawson's Classroom Test of Scientific Reasoning Ability (TSR) was administered once near mid-term for each sample. The Force Concept Inventory (FCI) was administered at the beginning and at the end of the term for pre- and post-test measures. Pre- and post-test data from the Mechanics Language Usage instrument were also collected in conjunction with FCI data collection at the beginning and end of the term. The MLU was developed specifically for this study prior to data collection, and results of a pilot test to establish validity and reliability are reported. T-tests were performed on the data collected to compare the means from each sample. In addition, correlations among the measures were investigated between the samples separately and combined. Results from these investigations served as justification for combining the samples into a single sample of 230 for performing further statistical analyses. The primary objective of this study was to determine if scientific reasoning ability (a function of developmental stage) and conceptual gains in Newtonian mechanics predict students' usages of "force" as measured by the MLU. Regression analyses were performed to evaluate these mediated relationships among TSR and FCI performance as a predictor of MLU performance. Statistically significant correlations and relationships existed among several of the measures, which are discussed at length in the body of the narrative. The findings of this research are that although there exists a discernable relationship between reasoning ability and conceptual change, more work needs to be done to establish improved quantitative measures of the role language usage has in developing understandings of course content.

Acute ENaC Stimulation by cAMP in a Kidney Cell Line is Mediated by Exocytic Insertion from a Recycling Channel Pool

PubMed Central

Butterworth, Michael B.; Edinger, Robert S.; Johnson, John P.; Frizzell, Raymond A.

2005-01-01

Acute hormonal regulation of the epithelial sodium channel (ENaC) in tight epithelia increases transcellular Na+ transport via trafficking of intracellular channels to the apical surface. The fate of the channels removed from the apical surface following agonist washout is less clear. By repetitively stimulating polarized mouse cortical collecting duct (mCCD, MPKCCD14) epithelia, we evaluated the hypothesis that ENaC recycles through an intracellular pool to be available for reinsertion into the apical membrane. Short circuit current (ISC), membrane capacitance (CT), and conductance (GT) were recorded from mCCD epithelia mounted in modified Ussing chambers. Surface biotinylation of ENaC demonstrated an increase in channel number in the apical membrane following cAMP stimulation. This increase was accompanied by a 83 ± 6% (n = 31) increase in ISC and a 15.3 ± 1.5% (n = 15) increase in CT. Selective membrane permeabilization demonstrated that the CT increase was due to an increase in apical membrane capacitance. ISC and CT declined to basal levels on stimulus washout. Repetitive cAMP stimulation and washout (∼1 h each cycle) resulted in response fatigue; ΔISC decreased ∼10% per stimulation–recovery cycle. When channel production was blocked by cycloheximide, ΔISC decreased ∼15% per stimulation cycle, indicating that newly synthesized ENaC contributed a relatively small fraction of the channels mobilized to the apical membrane. Selective block of surface ENaC by benzamil demonstrated that channels inserted from a subapical pool made up >90% of the stimulated ISC, and that on restimulation a large proportion of channels retrieved from the apical surface were reinserted into the apical membrane. Channel recycling was disrupted by brefeldin A, which inhibited ENaC exocytosis, by chloroquine, which inhibited ENaC endocytosis and recycling, and by latrunculin A, which blocked ENaC exocytosis. A compartment model featuring channel populations in the apical membrane and intracellular recycling pool provided an adequate kinetic description of the ISC responses to repetitive stimulation. The model supports the concept of ENaC recycling in response to repetitive cAMP stimulation. PMID:15623897

Near-limit propagation of gaseous detonations in narrow annular channels

NASA Astrophysics Data System (ADS)

Gao, Y.; Ng, H. D.; Lee, J. H. S.

2017-03-01

New results on the near-limit behaviors of gaseous detonations in narrow annular channels are reported in this paper. Annular channels of widths 3.2 and 5.9 mm were made using circular inserts in a 50.8 mm-diameter external tube. The length of each annular channel was 1.8 m. Detonations were initiated in a steel driver tube where a small volume of a sensitive C2H2+ 2.5O2 mixture was injected to facilitate detonation initiation. A 2 m length of circular tube with a 50.8 mm diameter preceded the annular channel so that a steady Chapman-Jouguet (CJ) detonation was established prior to entering the annular channel. Four detonable mixtures of C2H2 {+} 2.5O2 {+} 85 % Ar, C2H2 {+} 2.5O2 {+} 70 % Ar, C3H8 {+} 5O2, and CH4 {+} 2O2 were used in the present study. Photodiodes spaced 10 cm throughout the length of both the annular channel and circular tube were used to measure the detonation velocity. In addition, smoked foils were inserted into the annular channel to monitor the cellular structure of the detonation wave. The results show that, well within the detonability limits, the detonation wave propagates along the channel with a small local velocity fluctuation and an average global velocity can be deduced. The average detonation velocity has a small deficit of 5-15 % far from the limits and the velocity rapidly decreases to 0.7V_{CJ}-0.8V_{CJ} when the detonation propagates near the limit. Subsequently, the fluctuation of local velocity also increases as the decreasing initial pressure approaches the limit. In the two annular channels used in this work, no galloping detonations were observed for both the stable and unstable mixtures tested. The present study also confirms that single-headed spinning detonation occurs at the limit, as in a circular tube, rather than the up and down "zig zag" mode in a two-dimensional, rectangular channel.

Acute ENaC stimulation by cAMP in a kidney cell line is mediated by exocytic insertion from a recycling channel pool.

PubMed

Butterworth, Michael B; Edinger, Robert S; Johnson, John P; Frizzell, Raymond A

2005-01-01

Acute hormonal regulation of the epithelial sodium channel (ENaC) in tight epithelia increases transcellular Na(+) transport via trafficking of intracellular channels to the apical surface. The fate of the channels removed from the apical surface following agonist washout is less clear. By repetitively stimulating polarized mouse cortical collecting duct (mCCD, (MPK)CCD(14)) epithelia, we evaluated the hypothesis that ENaC recycles through an intracellular pool to be available for reinsertion into the apical membrane. Short circuit current (I(SC)), membrane capacitance (C(T)), and conductance (G(T)) were recorded from mCCD epithelia mounted in modified Ussing chambers. Surface biotinylation of ENaC demonstrated an increase in channel number in the apical membrane following cAMP stimulation. This increase was accompanied by a 83 +/- 6% (n = 31) increase in I(SC) and a 15.3 +/- 1.5% (n = 15) increase in C(T). Selective membrane permeabilization demonstrated that the C(T) increase was due to an increase in apical membrane capacitance. I(SC) and C(T) declined to basal levels on stimulus washout. Repetitive cAMP stimulation and washout (approximately 1 h each cycle) resulted in response fatigue; DeltaI(SC) decreased approximately 10% per stimulation-recovery cycle. When channel production was blocked by cycloheximide, DeltaI(SC) decreased approximately 15% per stimulation cycle, indicating that newly synthesized ENaC contributed a relatively small fraction of the channels mobilized to the apical membrane. Selective block of surface ENaC by benzamil demonstrated that channels inserted from a subapical pool made up >90% of the stimulated I(SC), and that on restimulation a large proportion of channels retrieved from the apical surface were reinserted into the apical membrane. Channel recycling was disrupted by brefeldin A, which inhibited ENaC exocytosis, by chloroquine, which inhibited ENaC endocytosis and recycling, and by latrunculin A, which blocked ENaC exocytosis. A compartment model featuring channel populations in the apical membrane and intracellular recycling pool provided an adequate kinetic description of the I(SC) responses to repetitive stimulation. The model supports the concept of ENaC recycling in response to repetitive cAMP stimulation.

Modular jet impingement assemblies with passive and active flow control for electronics cooling

DOEpatents

Zhou, Feng; Dede, Ercan Mehmet; Joshi, Shailesh

2016-09-13

Power electronics modules having modular jet impingement assembly utilized to cool heat generating devices are disclosed. The modular jet impingement assemblies include a modular manifold having a distribution recess, one or more angled inlet connection tubes positioned at an inlet end of the modular manifold that fluidly couple the inlet tube to the distribution recess and one or more outlet connection tubes positioned at an outlet end of the modular manifold that fluidly coupling the outlet tube to the distribution recess. The modular jet impingement assemblies include a manifold insert removably positioned within the distribution recess and include one or more inlet branch channels each including an impinging slot and one or more outlet branch channels each including a collecting slot. Further a heat transfer plate coupled to the modular manifold, the heat transfer plate comprising an impingement surface including an array of fins that extend toward the manifold insert.

Functional nicotinic acetylcholine receptor reconstitution in Au(111)-supported thiolipid monolayers

NASA Astrophysics Data System (ADS)

Pissinis, Diego E.; Diaz, Carolina; Maza, Eliana; Bonini, Ida C.; Barrantes, Francisco J.; Salvarezza, Roberto C.; Schilardi, Patricia L.

2015-09-01

The insertion and function of the muscle-type nicotinic acetylcholine receptor (nAChR) in Au(111)-supported thiolipid self-assembled monolayers have been studied by atomic force microscopy (AFM), surface plasmon resonance (SPR), and electrochemical techniques. It was possible for the first time to resolve the supramolecular arrangement of the protein spontaneously inserted in a thiolipid monolayer in an aqueous solution. Geometric supramolecular arrays of nAChRs were observed, most commonly in a triangular form compatible with three nAChR dimers of ~20 nm each. Addition of the full agonist carbamoylcholine activated and opened the nAChR ion channel, as revealed by the increase in capacitance relative to that of the nAChR-thiolipid system under basal conditions. Thus, the self-assembled system appears to be a viable biomimetic model to measure ionic conductance mediated by ion-gated ion channels under different experimental conditions, with potential applications in biotechnology and pharmacology.

Based on Cu as framework constructed nanoporous CuO/Cu composites by a dealloy method for sodium-ion battery anode

NASA Astrophysics Data System (ADS)

Zheng, Tian; Li, Guangda; Li, Deming; Meng, Xiangeng

2018-05-01

Nanoporous CuO/Cu composites with a continuous channel structure were fabricated through a corroding Cu-Al alloy process. The width of the continuous channels was about 20 50 nm. Nanoporous structure could effectively sustain the volume expansion during the Na+ insertion/extraction process and shorten the Na+ diffusion length as well, which thus helps improve the Na+ storage performance. Moreover, the nanoporous structure can improve the contact area between the electrolyte and the electrode, leading to an increment in the number of Na+ insertion/extraction sites. When used as the anode for sodium-ion batteries, the CuO/Cu exhibited an initial capacity of 580 mAh g-1, and the capacity is maintained at 200 mAh g-1 after 200 cycles at a current density of 500 mA g-1.

Bi-layer Channel AZO/ZnO Thin Film Transistors Fabricated by Atomic Layer Deposition Technique

NASA Astrophysics Data System (ADS)

Li, Huijin; Han, Dedong; Liu, Liqiao; Dong, Junchen; Cui, Guodong; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2017-03-01

This letter demonstrates bi-layer channel Al-doped ZnO/ZnO thin film transistors (AZO/ZnO TFTs) via atomic layer deposition process at a relatively low temperature. The effects of annealing in oxygen atmosphere at different temperatures have also been investigated. The ALD bi-layer channel AZO/ZnO TFTs annealed in dry O2 at 300 °C exhibit a low leakage current of 2.5 × 10-13A, I on/ I off ratio of 1.4 × 107, subthreshold swing (SS) of 0.23 V/decade, and high transmittance. The enhanced performance obtained from the bi-layer channel AZO/ZnO TFT devices is explained by the inserted AZO front channel layer playing the role of the mobility booster.

Insertion of linear 8.4 μm diameter 16 channel carbon fiber electrode arrays for single unit recordings

PubMed Central

Patel, Paras R.; Na, Kyounghwan; Zhang, Huanan; Kozai, Takashi D. Y.; Kotov, Nicholas A.; Yoon, Euisik; Chestek, Cynthia A.

2016-01-01

Objective Single carbon fiber electrodes (d=8.4 μm) insulated with parylene-c and functionalized with PEDOT:pTS have been shown to record single unit activity but manual implantation of these devices with forceps can be difficult. Without an improvement in the insertion method any increase in the channel count by fabricating carbon fiber arrays would be impractical. In this study, we utilize a water soluble coating and structural backbones that allow us to create, implant, and record from fully functionalized arrays of carbon fibers with ~150 μm pitch. Approach Two approaches were tested for the insertion of carbon fiber arrays. The first method used a PEG coating that temporarily stiffened the fibers while leaving a small portion at the tip exposed. The small exposed portion (500 μm – 1 mm) readily penetrated the brain allowing for an insertion that did not require the handling of each fiber by forceps. The second method involved the fabrication of silicon support structures with individual shanks spaced 150 μm apart. Each shank consisted of a small groove that held an individual carbon fiber. Main results Our results showed that the PEG coating allowed for the chronic implantation of carbon fiber arrays in 5 rats with unit activity detected at 31 days post-implant. The silicon support structures recorded single unit activity in 3 acute rat surgeries. In one of those surgeries a stacked device with 3 layers of silicon support structures and carbon fibers was built and shown to readily insert into the brain with unit activity on select sites. Significance From these studies we have found that carbon fibers spaced at ~150 μm readily insert into the brain. This greatly increases the recording density of chronic neural probes and paves the way for even higher density devices that have a minimal scarring response. PMID:26035638

Localization of PKA Phosphorylation Site, Serine-2030, in the Three-Dimensional Structure of Cardiac Ryanodine Receptor

PubMed Central

Jones, Peter P.; Meng, Xing; Xiao, Bailong; Cai, Shitian; Bolstad, Jeff; Wagenknecht, Terence; Liu, Zheng; Chen, S. R. Wayne

2009-01-01

Protein kinase A (PKA)-dependent phosphorylation of the cardiac Ca2+ release channel/ryanodine receptor (RyR2) is believed to directly dissociate FKBP12.6 from the channel, causing abnormal channel activation and Ca2+ release. To gain insight into the structural basis of the regulation of RyR2 by PKA, we determined the three-dimensional location of the PKA site S2030. Green fluorescent protein (GFP) was inserted into the wild type (wt) RyR2 and RyR2 mutant, A4860G, after T2023. The resultant GFP-RyR2 fusion proteins, RyR2T2023-GFP and RyR2(A4860G)T2023-GFP, were expressed in HEK293 cells and functionally characterized. Ca2+ release assays revealed that both GFP-RyR2 fusion proteins formed caffeine- and ryanodine-sensitive Ca2+ release channels. Further analyses using [3H]ryanodine binding demonstrated that the insertion of GFP into RyR2 wt after T2023 reduced the sensitivity of the channel to activation by Ca2+ or caffeine. RyR2(A4860G)T2023-GFP was found to be structurally more stable than RyR2T2023-GFP and was subsequently used as a basis for three-dimensional reconstruction. Cryo-electron microscopy and single particle image processing of the purified RyR2(A4860G)T2023-GFP protein revealed the location of the inserted GFP, and hence the S2030 PKA site in domain 4, a region that may be involved in signal transduction between the transmembrane and cytoplasmic domains. Like the S2808 PKA site reported previously, the S2030 site is not located close to the FKBP12.6 binding site mapped previously, indicating that neither of these PKA sites is directly involved in FKBP12.6 binding. Based on the three-dimensional localizations of a number of residues or regions, a model for the subunit organization in the structure of RyR2 is proposed. PMID:17967164

(Wh-)Indeterminates, Free Choice, and Expressive Content in Korean

ERIC Educational Resources Information Center

Park, Eun-Hae

2009-01-01

This dissertation investigates the semantics and pragmatics of two types of free choice items (FCIs) in Korean which employ a wh-indeterminate (i.e., wh-morphology. e.g., "nwukwu" "who/someone") and a non-deictic-indefinite (e.g., "amwu") respectively in combination with a suffixal particle--"na." Both wh-indeterminate-based FCI (wh-(N)-"na")…

Coping with Separation: An Analysis of Outcomes and Strategies Used by Working and Nonworking Wives during Routine Deployment. Part A

DTIC Science & Technology

1987-06-22

of approaching problems) and specfic coping efforts (behavioral or intra- psychic action taken in situations that are aimed at reducing stress... unemployed . Military Medicine, 1981, 146, 10. * I McCubbin, H.I., Boss, P., Wilson, L. & Dahl, B. Family Coping Inventory WI (FCI). In Family

Activation of the mechanosensitive ion channel MscL by mechanical stimulation of supported Droplet-Hydrogel bilayers

PubMed Central

Rosholm, Kadla R.; Baker, Matthew A. B.; Ridone, Pietro; Nakayama, Yoshitaka; Rohde, Paul R.; Cuello, Luis G.; Lee, Lawrence K.; Martinac, Boris

2017-01-01

The droplet on hydrogel bilayer (DHB) is a novel platform for investigating the function of ion channels. Advantages of this setup include tight control of all bilayer components, which is compelling for the investigation of mechanosensitive (MS) ion channels, since they are highly sensitive to their lipid environment. However, the activation of MS ion channels in planar supported lipid bilayers, such as the DHB, has not yet been established. Here we present the activation of the large conductance MS channel of E. coli, (MscL), in DHBs. By selectively stretching the droplet monolayer with nanolitre injections of buffer, we induced quantifiable DHB tension, which could be related to channel activity. The MscL activity response revealed that the droplet monolayer tension equilibrated over time, likely by insertion of lipid from solution. Our study thus establishes a method to controllably activate MS channels in DHBs and thereby advances studies of MS channels in this novel platform. PMID:28345591

Observation of backscattering-immune chiral electromagnetic modes without time reversal breaking.

PubMed

Chen, Wen-Jie; Hang, Zhi Hong; Dong, Jian-Wen; Xiao, Xiao; Wang, He-Zhou; Chan, C T

2011-07-08

A strategy is proposed to realize robust transport in a time reversal invariant photonic system. Using numerical simulation and a microwave experiment, we demonstrate that a chiral guided mode in the channel of a three-dimensional dielectric layer-by-layer photonic crystal is immune to the scattering of a square patch of metal or dielectric inserted to block the channel. The chirality based robust transport can be realized in nonmagnetic dielectric materials without any external field.

Light-activated control of protein channel assembly mediated by membrane mechanics

NASA Astrophysics Data System (ADS)

Miller, David M.; Findlay, Heather E.; Ces, Oscar; Templer, Richard H.; Booth, Paula J.

2016-12-01

Photochemical processes provide versatile triggers of chemical reactions. Here, we use a photoactivated lipid switch to modulate the folding and assembly of a protein channel within a model biological membrane. In contrast to the information rich field of water-soluble protein folding, there is only a limited understanding of the assembly of proteins that are integral to biological membranes. It is however possible to exploit the foreboding hydrophobic lipid environment and control membrane protein folding via lipid bilayer mechanics. Mechanical properties such as lipid chain lateral pressure influence the insertion and folding of proteins in membranes, with different stages of folding having contrasting sensitivities to the bilayer properties. Studies to date have relied on altering bilayer properties through lipid compositional changes made at equilibrium, and thus can only be made before or after folding. We show that light-activation of photoisomerisable di-(5-[[4-(4-butylphenyl)azo]phenoxy]pentyl)phosphate (4-Azo-5P) lipids influences the folding and assembly of the pentameric bacterial mechanosensitive channel MscL. The use of a photochemical reaction enables the bilayer properties to be altered during folding, which is unprecedented. This mechanical manipulation during folding, allows for optimisation of different stages of the component insertion, folding and assembly steps within the same lipid system. The photochemical approach offers the potential to control channel assembly when generating synthetic devices that exploit the mechanosensitive protein as a nanovalve.

Thermal management improvement of an air-cooled high-power lithium-ion battery by embedding metal foam

NASA Astrophysics Data System (ADS)

Mohammadian, Shahabeddin K.; Rassoulinejad-Mousavi, Seyed Moein; Zhang, Yuwen

2015-11-01

Effect of embedding aluminum porous metal foam inside the flow channels of an air-cooled Li-ion battery module was studied to improve its thermal management. Four different cases of metal foam insert were examined using three-dimensional transient numerical simulations. The effects of permeability and porosity of the porous medium as well as state of charge were investigated on the standard deviation of the temperature field and maximum temperature inside the battery in all four cases. Compared to the case of no porous insert, embedding aluminum metal foam in the air flow channel significantly improved the thermal management of Li-ion battery cell. The results also indicated that, decreasing the porosity of the porous structure decreases both standard deviation of the temperature field and maximum temperature inside the battery. Moreover, increasing the permeability of the metal foam drops the maximum temperature inside the battery while decreasing this property leads to improving the temperature uniformity. Our results suggested that, among the all studied cases, desirable temperature uniformity and maximum temperature were achieved when two-third and the entire air flow channel is filled with aluminum metal foam, respectively.

Evidence for a Retroviral Insertion in TRPM1 as the Cause of Congenital Stationary Night Blindness and Leopard Complex Spotting in the Horse

PubMed Central

Bellone, Rebecca R.; Holl, Heather; Setaluri, Vijayasaradhi; Devi, Sulochana; Maddodi, Nityanand; Archer, Sheila; Sandmeyer, Lynne; Ludwig, Arne; Foerster, Daniel; Pruvost, Melanie; Reissmann, Monika; Bortfeldt, Ralf; Adelson, David L.; Lim, Sim Lin; Nelson, Janelle; Haase, Bianca; Engensteiner, Martina; Leeb, Tosso; Forsyth, George; Mienaltowski, Michael J.; Mahadevan, Padmanabhan; Hofreiter, Michael; Paijmans, Johanna L. A.; Gonzalez-Fortes, Gloria; Grahn, Bruce; Brooks, Samantha A.

2013-01-01

Leopard complex spotting is a group of white spotting patterns in horses caused by an incompletely dominant gene (LP) where homozygotes (LP/LP) are also affected with congenital stationary night blindness. Previous studies implicated Transient Receptor Potential Cation Channel, Subfamily M, Member 1 (TRPM1) as the best candidate gene for both CSNB and LP. RNA-Seq data pinpointed a 1378 bp insertion in intron 1 of TRPM1 as the potential cause. This insertion, a long terminal repeat (LTR) of an endogenous retrovirus, was completely associated with LP, testing 511 horses (χ2=1022.00, p<<0.0005), and CSNB, testing 43 horses (χ2=43, p<<0.0005). The LTR was shown to disrupt TRPM1 transcription by premature poly-adenylation. Furthermore, while deleterious transposable element insertions should be quickly selected against the identification of this insertion in three ancient DNA samples suggests it has been maintained in the horse gene pool for at least 17,000 years. This study represents the first description of an LTR insertion being associated with both a pigmentation phenotype and an eye disorder. PMID:24167615

Evidence for a retroviral insertion in TRPM1 as the cause of congenital stationary night blindness and leopard complex spotting in the horse.

PubMed

Bellone, Rebecca R; Holl, Heather; Setaluri, Vijayasaradhi; Devi, Sulochana; Maddodi, Nityanand; Archer, Sheila; Sandmeyer, Lynne; Ludwig, Arne; Foerster, Daniel; Pruvost, Melanie; Reissmann, Monika; Bortfeldt, Ralf; Adelson, David L; Lim, Sim Lin; Nelson, Janelle; Haase, Bianca; Engensteiner, Martina; Leeb, Tosso; Forsyth, George; Mienaltowski, Michael J; Mahadevan, Padmanabhan; Hofreiter, Michael; Paijmans, Johanna L A; Gonzalez-Fortes, Gloria; Grahn, Bruce; Brooks, Samantha A

2013-01-01

Leopard complex spotting is a group of white spotting patterns in horses caused by an incompletely dominant gene (LP) where homozygotes (LP/LP) are also affected with congenital stationary night blindness. Previous studies implicated Transient Receptor Potential Cation Channel, Subfamily M, Member 1 (TRPM1) as the best candidate gene for both CSNB and LP. RNA-Seq data pinpointed a 1378 bp insertion in intron 1 of TRPM1 as the potential cause. This insertion, a long terminal repeat (LTR) of an endogenous retrovirus, was completely associated with LP, testing 511 horses (χ(2)=1022.00, p<0.0005), and CSNB, testing 43 horses (χ(2)=43, p<0.0005). The LTR was shown to disrupt TRPM1 transcription by premature poly-adenylation. Furthermore, while deleterious transposable element insertions should be quickly selected against the identification of this insertion in three ancient DNA samples suggests it has been maintained in the horse gene pool for at least 17,000 years. This study represents the first description of an LTR insertion being associated with both a pigmentation phenotype and an eye disorder.

Bi-layer Channel AZO/ZnO Thin Film Transistors Fabricated by Atomic Layer Deposition Technique.

PubMed

Li, Huijin; Han, Dedong; Liu, Liqiao; Dong, Junchen; Cui, Guodong; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2017-12-01

This letter demonstrates bi-layer channel Al-doped ZnO/ZnO thin film transistors (AZO/ZnO TFTs) via atomic layer deposition process at a relatively low temperature. The effects of annealing in oxygen atmosphere at different temperatures have also been investigated. The ALD bi-layer channel AZO/ZnO TFTs annealed in dry O 2 at 300 °C exhibit a low leakage current of 2.5 × 10 -13 A, I on /I off ratio of 1.4 × 10 7 , subthreshold swing (SS) of 0.23 V/decade, and high transmittance. The enhanced performance obtained from the bi-layer channel AZO/ZnO TFT devices is explained by the inserted AZO front channel layer playing the role of the mobility booster.

Quantitative multiplex detection of pathogen biomarkers

DOEpatents

Mukundan, Harshini; Xie, Hongzhi; Swanson, Basil I.; Martinez, Jennifer; Grace, Wynne K.

2016-02-09

The present invention addresses the simultaneous detection and quantitative measurement of multiple biomolecules, e.g., pathogen biomarkers through either a sandwich assay approach or a lipid insertion approach. The invention can further employ a multichannel, structure with multi-sensor elements per channel.

Quantitative multiplex detection of pathogen biomarkers

DOEpatents

Mukundan, Harshini; Xie, Hongzhi; Swanson, Basil I; Martinez, Jennifer; Grace, Wynne K

2014-10-14

The present invention addresses the simultaneous detection and quantitative measurement of multiple biomolecules, e.g., pathogen biomarkers through either a sandwich assay approach or a lipid insertion approach. The invention can further employ a multichannel, structure with multi-sensor elements per channel.

A feasibility study for using ABS plastic and a low-cost 3D printer for patient-specific brachytherapy mould design.

PubMed

Harris, Benjamin D; Nilsson, Sanna; Poole, Christopher M

2015-09-01

This feasibility study aims to determine if a low-cost 3D printer (BitsFromBytes 3D Touch) with ABS plastic can print custom mould structures and catheter channels defined in a brachytherapy treatment planning system (Nucletron Oncentra) for patient-specific treatment. Printer accuracy was evaluated through physical measurement, and print quality was investigated by adjusting print parameters (print speed, layer thickness, percentage infill). Catheter positioning and reproducibility were measured over repeated insertions. ABS plastic water equivalency was investigated by comparing Ir-192 HDR source dose distributions, measured with radiochromic film, in ABS plastic and in water. Structures and catheter channels were printed accurately to within 0.5 mm laterally and 1 mm in the vertical print direction. Adjusting print parameters could reduce print time, albeit with reduced print quality. 3.5 mm channel diameters allowed for easy catheter insertion. Catheter positioning was reproducible to within 0.5 mm but, because of catheter flex within the channel, was on average 1 mm offset from defined TPS positions. This offset could be accounted for by repeating the treatment planning CT scan with the printed mould positioned on the patient. Dose attenuation in ABS plastic and in water was equivalent to within the measurement limitations. While clinical uses for this particular low-cost printer and ABS plastic are limited by print size restrictions and non-certification for biocompatibility, it has been demonstrated that a low-cost 3D printer set-up can accurately create custom moulds and catheter channels potentially acceptable for clinical use.

Enlargement and contracture of C2-ceramide channels.

PubMed

Siskind, Leah J; Davoody, Amirparviz; Lewin, Naomi; Marshall, Stephanie; Colombini, Marco

2003-09-01

Ceramides are known to play a major regulatory role in apoptosis by inducing cytochrome c release from mitochondria. We have previously reported that ceramide, but not dihydroceramide, forms large and stable channels in phospholipid membranes and outer membranes of isolated mitochondria. C(2)-ceramide channel formation is characterized by conductance increments ranging from <1 to >200 nS. These conductance increments often represent the enlargement and contracture of channels rather than the opening and closure of independent channels. Enlargement is supported by the observation that many small conductance increments can lead to a large decrement. Also the initial conductances favor cations, but this selectivity drops dramatically with increasing total conductance. La(+3) causes rapid ceramide channel disassembly in a manner indicative of large conducting structures. These channels have a propensity to contract by a defined size (often multiples of 4 nS) indicating the formation of cylindrical channels with preferred diameters rather than a continuum of sizes. The results are consistent with ceramides forming barrel-stave channels whose size can change by loss or insertion of multiple ceramide columns.

Enlargement and Contracture of C2-Ceramide Channels

PubMed Central

Siskind, Leah J.; Davoody, Amirparviz; Lewin, Naomi; Marshall, Stephanie; Colombini, Marco

2003-01-01

Ceramides are known to play a major regulatory role in apoptosis by inducing cytochrome c release from mitochondria. We have previously reported that ceramide, but not dihydroceramide, forms large and stable channels in phospholipid membranes and outer membranes of isolated mitochondria. C2-ceramide channel formation is characterized by conductance increments ranging from <1 to >200 nS. These conductance increments often represent the enlargement and contracture of channels rather than the opening and closure of independent channels. Enlargement is supported by the observation that many small conductance increments can lead to a large decrement. Also the initial conductances favor cations, but this selectivity drops dramatically with increasing total conductance. La+3 causes rapid ceramide channel disassembly in a manner indicative of large conducting structures. These channels have a propensity to contract by a defined size (often multiples of 4 nS) indicating the formation of cylindrical channels with preferred diameters rather than a continuum of sizes. The results are consistent with ceramides forming barrel-stave channels whose size can change by loss or insertion of multiple ceramide columns. PMID:12944273

78 FR 19193 - Richard Phillips, Currently Incarcerated at: Inmate No. 81783-079, FCI Ray Brook Federal...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-29

...'') was convicted of violating the International Emergency Economic Powers Act (50 U.S.C. 1701, et seq..., license, or order issued under the International Emergency Economic Powers Act (50 U.S.C. 1701-1706); 18.... Obtain from the Denied Person in the United States any item subject to the Regulations with knowledge or...

Validating Two Questions in the Force Concept Inventory with Subquestions

ERIC Educational Resources Information Center

Yasuda, Jun-ichiro; Taniguchi, Masa-aki

2013-01-01

In this study, we evaluate the structural validity of Q.16 and Q.7 in the Force Concept Inventory (FCI). We address whether respondents who answer Q.16 and Q.7 correctly actually have an understanding of the concepts of physics tested in the questions. To examine respondents' levels of understanding, we use subquestions that test them on concepts…

78 FR 37788 - In the Matter of: Juan Ricardo Puente-Paez, Inmate Number #05086-379, FCI McDowell, Federal...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-24

... exported from the United States to Mexico four military spec Interceptor body armor vests, which were... owned, possessed or controlled by the Denied Person, or service any item, of whatever origin, that is... subject to the Regulations are the foreign-produced direct product of U.S.-origin technology. V. This...

The Presence of Gender Disparity on the Force Concept Inventory in a Sample of Canadian Undergraduate Students

ERIC Educational Resources Information Center

Normandeau, Magdalen; Iyengar, Seshu; Newling, Benedict

2017-01-01

Concept inventories (CI) are validated, research-based, multiple-choice tests, which are widely used to assess the effectiveness of pedagogical practices in bringing about conceptual change. In order to be a useful diagnostic tool, a CI must reflect only the student understanding of the conceptual material. The Force Concept Inventory (FCI) is…

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2013-06-11

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Understanding the relationship between student attitudes and student learning

NASA Astrophysics Data System (ADS)

Cahill, Michael J.; McDaniel, Mark A.; Frey, Regina F.; Hynes, K. Mairin; Repice, Michelle; Zhao, Jiuqing; Trousil, Rebecca

2018-02-01

Student attitudes, defined as the extent to which one holds expertlike beliefs about and approaches to physics, are a major research topic in physics education research. An implicit but rarely tested assumption underlying much of this research is that student attitudes play a significant part in student learning and performance. The current study directly tested this attitude-learning link by measuring the association between incoming attitudes (Colorado Learning Attitudes about Science Survey) and student learning during the semester after statistically controlling for the effects of prior knowledge [early-semester Force Concept Inventory (FCI) or Brief Electricity and Magnetism Assessment (BEMA)]. This study spanned four different courses and included two complementary measures of student knowledge: late-semester concept inventory scores (FCI or BEMA) and exam averages. In three of the four courses, after controlling for prior knowledge, attitudes significantly predicted both late-semester concept inventory scores and exam averages, but in all cases these attitudes explained only a small amount of variance in concept-inventory and exam scores. Results indicate that after accounting for students' incoming knowledge, attitudes may uniquely but modestly relate to how much students learn and how well they perform in the course.

Surgical Stabilization of Costoclavicular Injuries - A Combination of Flail Chest Injuries and a Clavicula Fracture.

PubMed

Langenbach, Andreas; Pinther, Melina; Krinner, Sebastian; Grupp, Sina; Ekkernkamp, Axel; Hennig, Friedrich F; Schulz-Drost, Stefan

2017-01-01

Background: Flail chest injuries (FCI) are associated with a high morbidity and mortality rate. As a concomitant clavicle fracture in FCI even worsens the outcome, the question is how can those costoclavicular injuries (CCI) be managed surgically. Methods: 11 patients with CCI were surgically treated by a locked plate osteosynthesis of the Clavicle and the underlying ribs through limited surgical approaches under general anesthesia. Patients were followed up after 2, 6, 12, 26 and 52 weeks. Results: All patients showed severe chest wall deformity due to severely displaced fractures of the ribs and the clavicle. They were suffering from pain and restriction of respiratory movements. The chest wall could be restored to normal shape in all cases with uneventful bone healing and a high patient convenience. Fractures of the clavicle and the second rib were managed through an innovative clavipectoral approach, the others through standard approaches to the anterolateral and the posterolateral chest wall. Two patients complained about numbness around the lateral approach and lasting periscapular pain. Conclusions: Surgical stabilization might be the appropriate therapy in CCI with dislocated fractures since they would cause severe deformity and loss of function of the chest wall and the shoulder. Celsius.

Meta-analysis of teaching methods: a 50k+ student study

NASA Astrophysics Data System (ADS)

Sayre, Eleanor; Archibeque, Benjamin; Gomez, K. Alison; Heckendorf, Tyrel; Madsen, Adrian M.; McKagan, Sarah B.; Schenk, Edward W.; Shepard, Chase; Sorell, Lane; von Korff, Joshua

2015-04-01

The Force Concept Inventory (FCI) and the Force and Motion Conceptual Evaluation (FMCE) are the two most widely-used conceptual tests in introductory mechanics. Because they are so popular, they provide an excellent avenue to compare different teaching methods at different kinds of institutions with varying student populations. We conducted a secondary analysis of all peer-reviewed papers which publish data from US and Canadian colleges and universities. Our data include over fifty thousand students drawn from approximately 100 papers; papers were drawn from Scopus, ERIC, ComPADRE, and journal websites. We augment published data about teaching methods with institutional data such as Carnegie Classification and average SAT scores. We statistically determine the effectiveness of different teaching methods as measured by FCI and FMCE gains and mediated by institutional and course factors. As in the landmark 1998 Hake study, we find that classes using interactive engagement (IE) have significantly larger learning gains than classes using traditional instruction. However, we find a broader distribution of normalized gains occurs in each of traditional and IE classes, and the differences between IE and traditional instruction have changed over time and are more context dependent.

Seniority and orbital symmetry as tools for establishing a full configuration interaction hierarchy.

PubMed

Bytautas, Laimutis; Henderson, Thomas M; Jiménez-Hoyos, Carlos A; Ellis, Jason K; Scuseria, Gustavo E

2011-07-28

We explore the concept of seniority number (defined as the number of unpaired electrons in a determinant) when applied to the problem of electron correlation in atomic and molecular systems. Although seniority is a good quantum number only for certain model Hamiltonians (such as the pairing Hamiltonian), we show that it provides a useful partitioning of the electronic full configuration interaction (FCI) wave function into rapidly convergent Hilbert subspaces whose weight diminishes as its seniority number increases. The primary focus of this study is the adequate description of static correlation effects. The examples considered are the ground states of the helium, beryllium, and neon atoms, the symmetric dissociation of the N(2) and CO(2) molecules, as well as the symmetric dissociation of an H(8) hydrogen chain. It is found that the symmetry constraints that are normally placed on the spatial orbitals greatly affect the convergence rate of the FCI expansion. The energy relevance of the seniority zero sector (determinants with all paired electrons) increases dramatically if orbitals of broken spatial symmetry (as those commonly used for Hubbard Hamiltonian studies) are allowed in the wave function construction. © 2011 American Institute of Physics

Method for fabricating multi-strand superconducting cable

DOEpatents

Borden, A.R.

1985-04-01

Multi-strand superconducting cables adapted to be used, for example, to wind a magnet are fabricated by directing wire strands inwardly from spools disposed on the perimeter of a rotating disk and wrapping them diagonally around a tapered mandrel with a flattened cross-sectional shape with a core having a wedge-shaped channel. As the cable is pulled axially, flexibly coupled wedge-shaped pieces are continuously passed through the channel in the mandrel and inserted into the cable as an internal support therefor.

Apparatus and method for fabricating multi-strand superconducting cable

DOEpatents

Borden, Albert R.

1986-01-01

Multi-strand superconducting cables adapted to be used, for example, to wind a magnet is fabricated by directing wire strands inwardly from spools disposed on the perimeter of a rotating disk and wrapping them diagonally around a tapered mandrel with a flattened cross-sectional shape with a core having a wedge-shaped channel. As the cable is pulled axially, flexibly coupled wedge-shaped pieces are continuously passed through the channel in the mandrel and inserted into the cable as an internal support therefor.

Rare Gases Inserted into Biological Building Blocks: A Theoretical Study of Glycine - Rg Compounds (Rg-Xe, Kr, Ar)

NASA Technical Reports Server (NTRS)

Chaban, Galina M.

2005-01-01

Compounds formed by insertion of rare-gas atoms (Xe, Kr, and Ar) into glycine molecule are investigated using accurate ab initio computational methods. Identification of such insertion compounds may open new frontiers in the field of rare-gas chemistry, such as possible existence of biological molecules that include chemically bound rare gas atoms. The most stable glycine-Rg configuration is found to correspond to insertion of Rg atoms into the 0-H bond of glycine. These NH2CH2COORgH compounds are metastable , but separated by sizable potential barriers from the Rg + glycine dissociation products. Preliminary calculations show that NH2CH2COOXeH compound is energetically stable with respect to another (3-body) dissociation channel (NH2CH2COO + Rg + H), while the corresponding Ar species is not stable in this respect. The compound with the inserted Kr is a borderline case, with the 3-body dissociation products being close in energy to the NH2CH2COOKrH minimum.

Long distance quantum communication using quantum error correction

NASA Technical Reports Server (NTRS)

Gingrich, R. M.; Lee, H.; Dowling, J. P.

2004-01-01

We describe a quantum error correction scheme that can increase the effective absorption length of the communication channel. This device can play the role of a quantum transponder when placed in series, or a cyclic quantum memory when inserted in an optical loop.

"Space slitter" for film or tape

NASA Technical Reports Server (NTRS)

Johnson, W. H.

1978-01-01

Device cuts film or tape into strips by guiding film in channel under cutting blades. Device is operated by lifting pressure bar to insert blades into film. Film is then pulled through blades. Cutter has potential uses in advertising, commercial art, and publishing fields.

Investigating High Frequency Magnetic Activity During Local Helicity Injection on the Pegasus Toroidal Experiment

NASA Astrophysics Data System (ADS)

Richner, N. J.; Bongard, M. W.; Fonck, R. J.; Pachicano, J. L.; Perry, J. M.; Reusch, J. A.

2017-10-01

Understanding the current drive mechanism(s) of Local Helicity Injection (LHI) is needed for confident scaling to next-step devices. 3D resistive MHD NIMROD simulations ascribe large-scale reconnection events of helical injector current streams as a current drive mechanism. The events generate n = 1 B fluctuations on outboard Mirnov coils, consistent with experiment. New results suggest additional mechanisms are also active during LHI. Reconnection-driven ion heating is better correlated with high frequency activity than the n = 1 bursts. Experiments with inboard injectors can exhibit an abrupt ( 250 μs) transition to a reduced MHD state on outboard Mirnovs where the n = 1 feature vanishes, while still maintaining current growth and/or sustainment. A new insertable magnetics probe was developed to investigate these phenomena. It measures TeXBz up to 3.5 MHz at 15 points over a 14 cm radial extent (ΔR 1 cm). Measurements with this probe are consistent with the outboard Mirnovs when positioned far from the plasma boundary. However, measurements near the plasma edge lack the reduction in broadband power (up to 2 MHz) following the transition. The probe shows power is concentrated at higher frequencies during LHI, with mostly flat B spectra up to 600-800 kHz ( fci) at which there is a resonance-like feature; at higher frequencies, the power decreases. These measurements suggest short-wavelength activity may play a significant role in LHI current drive. Work supported by US DOE Grant DE-FG02-96ER54375.

Membrane peptides and their role in protobiological evolution

NASA Technical Reports Server (NTRS)

Pohorille, Andrew; Wilson, Michael A.; Chipot, Christophe

2003-01-01

How simple membrane peptides performed such essential protocellular functions as transport of ions and organic matter across membranes separating the interior of the cell from the environment, capture and utilization of energy, and transduction of environmental signals, is a key question in protobiological evolution. On the basis of detailed, molecular-level computer simulations we explain how these peptides fold at water-membrane interfaces, insert into membranes, self-assemble into higher-order structures and acquire functions. We have investigated the interfacial behavior and folding of several peptides built of leucine and glutamine residues and have demonstrated that many of them tend to adopt ordered structures. Further, we have studied the insertion of an alpha-helical peptide containing leucine (L) and serine (S) of the form (LSLLLSL)3 into a model membrane. The transmembrane state is metastable, and approximately 15 kcal mol(-1) is required to insert the peptide into the membrane. Investigations of dimers formed by (LSLLLSL)3 and glycophorin A demonstrate how the favorable free energy of helix association can offset the unfavorable free energy of insertion, leading to self-assembly of peptide helices in the membrane. An example of a self-assembled structure is the tetrameric transmembrane pore of the influenza virus M2 protein, which is an efficient and selective voltage-gated proton channel. Our simulations explain the gating mechanism and provide guidelines how to re-engineer the channel to act as a simple proton pump. In general, emergence of integral membrane proteins appears to be quite feasible and may be easier to envision than the emergence of water-soluble proteins.

Prospects of zero Schottky barrier height in a graphene-inserted MoS2-metal interface

NASA Astrophysics Data System (ADS)

Chanana, Anuja; Mahapatra, Santanu

2016-01-01

A low Schottky barrier height (SBH) at source/drain contact is essential for achieving high drive current in atomic layer MoS2-channel-based field effect transistors. Approaches such as choosing metals with appropriate work functions and chemical doping are employed previously to improve the carrier injection from the contact electrodes to the channel and to mitigate the SBH between the MoS2 and metal. Recent experiments demonstrate significant SBH reduction when graphene layer is inserted between metal slab (Ti and Ni) and MoS2. However, the physical or chemical origin of this phenomenon is not yet clearly understood. In this work, density functional theory simulations are performed, employing pseudopotentials with very high basis sets to get insights of the charge transfer between metal and monolayer MoS2 through the inserted graphene layer. Our atomistic simulations on 16 different interfaces involving five different metals (Ti, Ag, Ru, Au, and Pt) reveal that (i) such a decrease in SBH is not consistent among various metals, rather an increase in SBH is observed in case of Au and Pt; (ii) unlike MoS2-metal interface, the projected dispersion of MoS2 remains preserved in any MoS2-graphene-metal system with shift in the bands on the energy axis. (iii) A proper choice of metal (e.g., Ru) may exhibit ohmic nature in a graphene-inserted MoS2-metal contact. These understandings would provide a direction in developing high-performance transistors involving heteroatomic layers as contact electrodes.

Voltage-dependent blockade of muscle Na+ channels by guanidinium toxins

PubMed Central

1984-01-01

Na+ channels from rat muscle plasma membrane vesicles were inserted into neutral planar phospholipid bilayers and were activated by batrachotoxin. Single channel blocking events induced by the addition of various guanidinium toxins were analyzed to derive the rates of channel-toxin association and dissociation. Blocking by tetrodotoxin, saxitoxin, and six natural saxitoxin derivatives containing sulfate or hydroxyl groups were studied. Although the binding affinities vary over 2,000-fold, all of the toxins exhibit identical voltage dependence of the blocking reactions, regardless of the toxin's net charge. The results suggest that the voltage dependence of toxin binding is due to a voltage-dependent conformational equilibrium of the toxin receptor, rather than to direct entry of the charged toxin molecule into the applied transmembrane electric field. PMID:6096479

Generation of Myostatin Gene-Edited Channel Catfish (Ictalurus punctatus) via Zygote Injection of CRISPR/Cas9 System.

PubMed

Khalil, Karim; Elayat, Medhat; Khalifa, Elsayed; Daghash, Samer; Elaswad, Ahmed; Miller, Michael; Abdelrahman, Hisham; Ye, Zhi; Odin, Ramjie; Drescher, David; Vo, Khoi; Gosh, Kamal; Bugg, William; Robinson, Dalton; Dunham, Rex

2017-08-04

The myostatin (MSTN) gene is important because of its role in regulation of skeletal muscle growth in all vertebrates. In this study, CRISPR/Cas9 was utilized to successfully target the channel catfish, Ictalurus punctatus, muscle suppressor gene MSTN. CRISPR/Cas9 induced high rates (88-100%) of mutagenesis in the target protein-encoding sites of MSTN. MSTN-edited fry had more muscle cells (p < 0.001) than controls, and the mean body weight of gene-edited fry increased by 29.7%. The nucleic acid alignment of the mutated sequences against the wild-type sequence revealed multiple insertions and deletions. These results demonstrate that CRISPR/Cas9 is a highly efficient tool for editing the channel catfish genome, and opens ways for facilitating channel catfish genetic enhancement and functional genomics. This approach may produce growth-enhanced channel catfish and increase productivity.

Strain relief for power-cable connectors

NASA Technical Reports Server (NTRS)

Dean, W. T., III

1980-01-01

Easily fabricated grommet composed of polytetrafluoroethylene cylinder, containing U-shaped channels equally spaced around periphery, is used in power cable connectors to relieve strain on cables. Utilization of grommets provides more ease in cable insertion and removal. Potential applications include wiring in large residential and commercial buildings.

Sensitivity Analysis of Digital I&C Modules in Protection and Safety Systems

NASA Astrophysics Data System (ADS)

Khalil Ur, Rahman; Zubair, M.; Heo, G.

2013-12-01

This research is performed to examine the sensitivity of digital Instrumentation and Control (I&C) components and modules used in regulating and protection systems architectures of nuclear industry. Fault Tree Analysis (FTA) was performed for four configurations of RPS channel architecture. The channel unavailability has been calculated by using AIMS-PSA, which comes out 4.517E-03, 2.551E-03, 2.246E-03 and 2.7613-04 for architecture configuration I, II, III and IV respectively. It is observed that unavailability decreases by 43.5 % & 50.4% by inserting partial redundancy whereas maximum reduction of 93.9 % in unavailability happens when double redundancy is inserted in architecture. Coincidence module output failure and bi-stable output failures are identified as sensitive failures by Risk Reduction Worth (RRW) and Fussell-Vesely (FV) importance. RRW highlights that risk from coincidence processor output failure can reduced by 48.83 folds and FV indicates that BP output is sensitive by 0.9796 (on a scale of 1).

Severe manifestation of Bartter syndrome Type IV caused by a novel insertion mutation in the BSND gene.

PubMed

de Pablos, Augusto Luque; García-Nieto, Victor; López-Menchero, Jesús C; Ramos-Trujillo, Elena; González-Acosta, Hilaria; Claverie-Martín, Félix

2014-05-01

Bartter syndrome Type IV is a rare subtype of the Bartter syndromes that leads to both severe renal salt wasting and sensorineural deafness. This autosomal recessive disease is caused by mutations in the gene encoding barttin, BSND, an essential subunit of the ClC-K chloride channels expressed in renal and inner ear epithelia. Patients differ in the severity of renal symptoms, which appears to depend on the modification of channel function by the mutant barttin. To date, only a few BSND mutations have been reported, most of which are missense or nonsense mutations. In this study, we report the identification of the first insertion mutation, p.W102Vfs*7, in the BSND gene of a newborn girl with acute clinical symptoms including early-onset chronic renal failure. The results support previous data indicating that mutations that are predicted to abolish barttin expression are associated with a severe phenotype and early onset renal failure.

Memristive Ion Channel-Doped Biomembranes as Synaptic Mimics.

PubMed

Najem, Joseph S; Taylor, Graham J; Weiss, Ryan J; Hasan, Md Sakib; Rose, Garrett; Schuman, Catherine D; Belianinov, Alex; Collier, C Patrick; Sarles, Stephen A

2018-05-22

Solid-state neuromorphic systems based on transistors or memristors have yet to achieve the interconnectivity, performance, and energy efficiency of the brain due to excessive noise, undesirable material properties, and nonbiological switching mechanisms. Here we demonstrate that an alamethicin-doped, synthetic biomembrane exhibits memristive behavior, emulates key synaptic functions including paired-pulse facilitation and depression, and enables learning and computing. Unlike state-of-the-art devices, our two-terminal, biomolecular memristor features similar structure (biomembrane), switching mechanism (ion channels), and ionic transport modality as biological synapses while operating at considerably lower power. The reversible and volatile voltage-driven insertion of alamethicin peptides into an insulating lipid bilayer creates conductive pathways that exhibit pinched current-voltage hysteresis at potentials above their insertion threshold. Moreover, the synapse-like dynamic properties of the biomolecular memristor allow for simplified learning circuit implementations. Low-power memristive devices based on stimuli-responsive biomolecules represent a major advance toward implementation of full synaptic functionality in neuromorphic hardware.

RELAP5 Application to Accident Analysis of the NIST Research Reactor

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

Baek, J.; Cuadra Gascon, A.; Cheng, L.Y.

Detailed safety analyses have been performed for the 20 MW D{sub 2}O moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The time-dependent analysis of the primary system is determined with a RELAP5 transient analysis model that includes the reactor vessel, the pump, heat exchanger, fuel element geometry, and flow channels for both the six inner and twenty-four outer fuel elements. A post-processing of the simulation results has been conducted to evaluate minimum critical heat flux ratio (CHFR) using the Sudo-Kaminaga correlation. Evaluations are performed for the following accidents: (1) the control rod withdrawal startup accidentmore » and (2) the maximum reactivity insertion accident. In both cases the RELAP5 results indicate that there is adequate margin to CHF and no damage to the fuel will occur because of sufficient coolant flow through the fuel channels and the negative scram reactivity insertion.« less

The transport of extremely low-frequency electrical signals through an acupuncture meridian compared to nonmeridian tissue.

PubMed

Spaulding, Keith; Chamberlin, Kent

2011-02-01

This study investigated the manner in which extremely low-frequency (ELF) electrical energy is transported through biologic tissues, focusing on the differences between an acupuncture meridian and nonmeridian tissues. Using inserted needles as the electrodes, the energy transport properties of the Large Intestine (LI) meridian were compared to a control channel that had the same length as the meridian channel and comprised similar soft tissue. Twenty (20) participants were tested at the University of New Hampshire, Durham, with ages ranging from 22 to 60 years old. A Gaussian pulse with spectral energy extending into the kilohertz range was launched using a low-impedance amplifier at the distal point on either the LI meridian or a nearby control channel. The signal launched was measured at the proximal point using a high-impedance instrumentation amplifier. The ground reference for both the launch and receiver locations was a needle inserted in the lower leg. After taking the Fast Fourier Transform, power spectral measurements were calculated, giving a single value representing power density of the measured potential in the 2-100-Hz range. A paired, two-sided signed rank test was performed. For the data pairs in this study, p = 0.035, indicating that they are dissimilar with a statistical significance. The ELF electric energy is transported somewhat more efficiently through the LI meridian compared to a nonmeridian control. The results were not dramatic, with some participants giving greater values on the control channel, but they were statistically significant.

A COMPARISON OF EXPERIMENTS AND THREE-DIMENSIONAL ANALYSIS TECHNIQUES. PART II. UNPOISONED UNIFORM SLAB CORE WITH A PARTIALLY INSERTED HAFNIUM ROD AND A PARTIALLY INSERTED WATER GAP

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

Roseberry, R.J.

The experimental measurements and nuclear analysis of a uniformly loaded, unpoisoned slab core with a partially inserted hafnium rod and/or a partially inserted water gap are described. Comparisons of experimental data with calculated results of the UFO core and flux synthesis techniques are given. It is concluded that one of the flux synthesis techniques and the UFO code are able to predict flux distributions to within approximately -5% of experiment for most cases, with a maximum error of approximately -10% for a channel at the core- reflector boundary. The second synthesis technique failed to give comparable agreement with experiment evenmore » when various refinements were used, e.g. increasing the number of mesh points, performing the flux synthesis technique of iteration, and spectrum-weighting the appropriate calculated fluxes through the use of the SWAKRAUM code. These results are comparable to those reported in Part I of this study. (auth)« less

Two potential calmodulin-binding sequences in the ryanodine receptor contribute to a mobile, intra-subunit calmodulin-binding domain

PubMed Central

Huang, Xiaojun; Liu, Ying; Wang, Ruiwu; Zhong, Xiaowei; Liu, Yingjie; Koop, Andrea; Chen, S. R. Wayne; Wagenknecht, Terence; Liu, Zheng

2013-01-01

Summary Calmodulin (CaM), a 16 kDa ubiquitous calcium-sensing protein, is known to bind tightly to the calcium release channel/ryanodine receptor (RyR), and modulate RyR function. CaM binding studies using RyR fragments or synthetic peptides have revealed the presence of multiple, potential CaM-binding regions in the primary sequence of RyR. In the present study, we inserted GFP into two of these proposed CaM-binding sequences and mapped them onto the three-dimensional structure of intact cardiac RyR2 by cryo-electron microscopy. Interestingly, we found that the two potential CaM-binding regions encompassing, Arg3595 and Lys4269, respectively, are in close proximity and are adjacent to the previously mapped CaM-binding sites. To monitor the conformational dynamics of these CaM-binding regions, we generated a fluorescence resonance energy transfer (FRET) pair, a dual CFP- and YFP-labeled RyR2 (RyR2R3595-CFP/K4269-YFP) with CFP inserted after Arg3595 and YFP inserted after Lys4269. We transfected HEK293 cells with the RyR2R3595-CFP/K4269-YFP cDNA, and examined their FRET signal in live cells. We detected significant FRET signals in transfected cells that are sensitive to the channel activator caffeine, suggesting that caffeine is able to induce conformational changes in these CaM-binding regions. Importantly, no significant FRET signals were detected in cells co-transfected with cDNAs encoding the single CFP (RyR2R3595-CFP) and single YFP (RyR2K4269-YFP) insertions, indicating that the FRET signal stemmed from the interaction between R3595–CFP and K4269–YFP that are in the same RyR subunit. These observations suggest that multiple regions in the RyR2 sequence may contribute to an intra-subunit CaM-binding pocket that undergoes conformational changes during channel gating. PMID:23868982

Analyzing False Positives of Four Questions in the Force Concept Inventory

ERIC Educational Resources Information Center

Yasuda, Jun-ichro; Mae, Naohiro; Hull, Michael M.; Taniguchi, Masa-aki

2018-01-01

In this study, we analyze the systematic error from false positives of the Force Concept Inventory (FCI). We compare the systematic errors of question 6 (Q.6), Q.7, and Q.16, for which clearly erroneous reasoning has been found, with Q.5, for which clearly erroneous reasoning has not been found. We determine whether or not a correct response to a…

Validating Proposed Learning Progressions on Force and Motion Using the Force Concept Inventory: Findings from Singapore Secondary Schools

ERIC Educational Resources Information Center

Fulmer, Gavin W.

2015-01-01

This study examines the validity of 2 proposed learning progressions on the force concept when tested using items from the Force Concept Inventory (FCI). This is the first study to compare students' performance with respect to learning progressions both for force and motion and for Newton's third law in parallel. It is also among the first studies…

The Development of Alternative Food Cost Indexes

DTIC Science & Technology

1974-11-01

Frozen frufts, vegetables , fruit juices , and cake mixes are added and the quantity of purchased bread increased in this FCI. Comment was made that some... Grain , Frozen Vegetables , Mixed, Frozen Beans, Green, Frozen Peaches, Canned Apples, Fresh Oranges, Fresh Strawberries, Frozen Juice , Pineapple...also falls to recognize such accepted food service practices as the use of frozen fruits , vegetables , and juices , or prepared cake mixes, Tj,e

A novel scheme to aid coherent detection of GMSK signals in fast Rayleigh fading channels

NASA Technical Reports Server (NTRS)

Leung, Patrick S. K.; Feher, Kamilo

1990-01-01

A novel scheme to insert carrier pilot to Gaussian Minimum Shift Keying (GMSK) signal using Binary Block Code (BBC) and a highpass filter in baseband is proposed. This allows the signal to be coherently demodulated even in a fast Rayleigh fading environment. As an illustrative example, the scheme is applied to a 16 kb/s GMSK signal, and its performance over a fast Rayleigh fading channel is investigated using computer simulation. This modem's 'irreducible error rate' is found to be Pe = 5.5 x 10(exp -5) which is more than that of differential detection. The modem's performance in Rician fading channel is currently under investigation.

Characterization of Ether-à-go-go Channels Present in Photoreceptors Reveals Similarity to IKx, a K+ Current in Rod Inner Segments

PubMed Central

Frings, Stephan; Brüll, Nicole; Dzeja, Claudia; Angele, Albert; Hagen, Volker; Kaupp, U. Benjamin; Baumann, Arnd

1998-01-01

In this study, we describe two splice variants of an ether-à-go-go (EAG) K+ channel cloned from bovine retina: bEAG1 and bEAG2. The bEAG2 polypeptide contains an additional insertion of 27 amino acids in the extracellular linker between transmembrane segments S3 and S4. The heterologously expressed splice variants differ in their activation kinetics and are differently modulated by extracellular Mg2+. Cooperativity of modulation by Mg2+ suggests that each subunit of the putative tetrameric channel binds a Mg2+ ion. The channels are neither permeable to Ca2+ ions nor modulated by cyclic nucleotides. In situ hybridization localizes channel transcripts to photoreceptors and retinal ganglion cells. Comparison of EAG currents with IKx, a noninactivating K+ current in the inner segment of rod photoreceptors, reveals an intriguing similarity, suggesting that EAG polypeptides are involved in the formation of Kx channels. PMID:9524140

80-Channel Multiplexer-Demultiplexer Module for DWDM Communications using Hybrid AWG -- Interleaver Technology

NASA Astrophysics Data System (ADS)

Rablau, Corneliu; Bredthauer, Lance

2007-10-01

Aside from the more traditional data, voice and e-mail communications, new bandwidth intensive applications in the larger consumer markets, such as music, digital pictures and movies, have led to an explosive increase in the demand for transmission capacity for optical communications networks. This has resulted in a widespread deployment of Dense Wavelength Division Multiplexing (DWDM) as a means of increasing the communications capacity by multiplexing and transmitting signals of different wavelengths (establishing multiple communication channels) through a single strand of fiber. We report on the design, assembly and characterization of a 50-GHz, 80-channel Mux-Demux module for DWDM systems. The module has been assembled from two commercially available 100 GHz, 40-channel Array Waveguide Grating (AWG) modules and a 50-GHz to 100-GHz interleaver. Relevant performance parameters such as insertion loss, channel uniformity, next-channel isolation (crosstalk) and integrated cross-talk are presented and discussed in contrast with the performance of other competing technologies such as Thin-Film-Filter-based Mux-Demux devices.

Damage-free back channel wet-etch process in amorphous indium-zinc-oxide thin-film transistors using a carbon-nanofilm barrier layer.

PubMed

Luo, Dongxiang; Zhao, Mingjie; Xu, Miao; Li, Min; Chen, Zikai; Wang, Lang; Zou, Jianhua; Tao, Hong; Wang, Lei; Peng, Junbiao

2014-07-23

Amorphous indium-zinc-oxide thin film transistors (IZO-TFTs) with damage-free back channel wet-etch (BCE) process were investigated. A carbon (C) nanofilm was inserted into the interface between IZO layer and source/drain (S/D) electrodes as a barrier layer. Transmittance electron microscope images revealed that the 3 nm-thick C nanofilm exhibited a good corrosion resistance to a commonly used H3PO4-based etchant and could be easily eliminated. The TFT device with a 3 nm-thick C barrier layer showed a saturated field effect mobility of 14.4 cm(2) V(-1) s(-1), a subthreshold swing of 0.21 V/decade, an on-to-off current ratio of 8.3 × 10(10), and a threshold voltage of 2.0 V. The favorable electrical performance of this kind of IZO-TFTs was due to the protection of the inserted C to IZO layer in the back-channel-etch process. Moreover, the low contact resistance of the devices was proved to be due to the graphitization of the C nanofilms after annealing. In addition, the hysteresis and thermal stress testing confirmed that the usage of C barrier nanofilms is an effective method to fabricate the damage-free BCE-type devices with high reliability.

The biological acoustic sensor to record the interactions of the microbial cells with the phage antibodies in conducting suspensions.

PubMed

Guliy, О I; Zaitsev, B D; Borodina, I A; Shikhabudinov, А М; Teplykh, A A; Staroverov, S A; Fomin, A S

2018-02-01

The acoustic biological sensor for the analysis of the bacterial cells in conducting suspension was developed. The sensor represented the two channel delay line based on the piezoelectric plate of Y-X lithium niobate thick of 0.2mm. Two pairs of the interdigital transducers (IDT) for the excitation and reception of shear horizontal acoustic wave of zero order (SH 0 ) in each channel were deposited by the method of photolithography. One channel of the delay line was electrically shorted by the deposition of thin aluminum film between IDTs. The second channel remained as electrically open. The liquid container with the volume of 5ml was fixed on the plate surface between IDTs by the glue, which did not cause the additional insertion loss. For the first time the influence of the conductivity of the cell suspension on the registration of the specific and nonspecific interactions of the bacterial cells with phage-antibodies (phage-Abs) was studied by means of the developed sensor. The dependencies of the change in insertion loss and phase of the output signal on the conductivity of the buffer solution at specific/nonspecific interactions for the electrically open and shorted channels of the delay line were obtained. It was shown that the sensor successfully registered the interactions of microbial cells with phage-Abs in the range of the conductivity of 2-20 μS/cm on the model samples A. brasilense Sp245 - specific phage-Abs. The sensor in the time regime of the operation fast reacted on the specific/nonspecific interaction and the time of the stabilization of the output parameters did not exceed 10min. Copyright © 2017 Elsevier B.V. All rights reserved.

Engineering of the E. coli outer membrane protein FhuA to overcome the hydrophobic mismatch in thick polymeric membranes.

PubMed

Muhammad, Noor; Dworeck, Tamara; Fioroni, Marco; Schwaneberg, Ulrich

2011-03-17

Channel proteins like the engineered FhuA Δ1-159 often cannot insert into thick polymeric membranes due to a mismatch between the hydrophobic surface of the protein and the hydrophobic surface of the polymer membrane. To address this problem usually specific block copolymers are synthesized to facilitate protein insertion. Within this study in a reverse approach we match the protein to the polymer instead of matching the polymer to the protein. To increase the FhuA Δ1-159 hydrophobic surface by 1 nm, the last 5 amino acids of each of the 22 β-sheets, prior to the more regular periplasmatic β-turns, were doubled leading to an extended FhuA Δ1-159 (FhuA Δ1-159 Ext). The secondary structure prediction and CD spectroscopy indicate the β-barrel folding of FhuA Δ1-159 Ext. The FhuA Δ1-159 Ext insertion and functionality within a nanocontainer polymeric membrane based on the triblock copolymer PIB(1000)-PEG(6000)-PIB(1000) (PIB = polyisobutylene, PEG = polyethyleneglycol) has been proven by kinetic analysis using the HRP-TMB assay (HRP = Horse Radish Peroxidase, TMB = 3,3',5,5'-tetramethylbenzidine). Identical experiments with the unmodified FhuA Δ1-159 report no kinetics and presumably no insertion into the PIB(1000)-PEG(6000)-PIB(1000) membrane. Furthermore labeling of the Lys-NH(2) groups present in the FhuA Δ1-159 Ext channel, leads to controllability of in/out flux of substrates and products from the nanocontainer. Using a simple "semi rational" approach the protein's hydrophobic transmembrane region was increased by 1 nm, leading to a predicted lower hydrophobic mismatch between the protein and polymer membrane, minimizing the insertion energy penalty. The strategy of adding amino acids to the FhuA Δ1-159 Ext hydrophobic part can be further expanded to increase the protein's hydrophobicity, promoting the efficient embedding into thicker/more hydrophobic block copolymer membranes.

Genomics analysis of potassium channel genes in songbirds reveals molecular specializations of brain circuits for the maintenance and production of learned vocalizations

PubMed Central

2013-01-01

Background A fundamental question in molecular neurobiology is how genes that determine basic neuronal properties shape the functional organization of brain circuits underlying complex learned behaviors. Given the growing availability of complete vertebrate genomes, comparative genomics represents a promising approach to address this question. Here we used genomics and molecular approaches to study how ion channel genes influence the properties of the brain circuitry that regulates birdsong, a learned vocal behavior with important similarities to human speech acquisition. We focused on potassium (K-)Channels, which are major determinants of neuronal cell excitability. Starting with the human gene set of K-Channels, we used cross-species mRNA/protein alignments, and syntenic analysis to define the full complement of orthologs, paralogs, allelic variants, as well as novel loci not previously predicted in the genome of zebra finch (Taeniopygia guttata). We also compared protein coding domains in chicken and zebra finch orthologs to identify genes under positive selective pressure, and those that contained lineage-specific insertions/deletions in functional domains. Finally, we conducted comprehensive in situ hybridizations to determine the extent of brain expression, and identify K-Channel gene enrichments in nuclei of the avian song system. Results We identified 107 K-Channel finch genes, including 6 novel genes common to non-mammalian vertebrate lineages. Twenty human genes are absent in songbirds, birds, or sauropsids, or unique to mammals, suggesting K-Channel properties may be lineage-specific. We also identified specific family members with insertions/deletions and/or high dN/dS ratios compared to chicken, a non-vocal learner. In situ hybridization revealed that while most K-Channel genes are broadly expressed in the brain, a subset is selectively expressed in song nuclei, representing molecular specializations of the vocal circuitry. Conclusions Together, these findings shed new light on genes that may regulate biophysical and excitable properties of the song circuitry, identify potential targets for the manipulation of the song system, and reveal genomic specializations that may relate to the emergence of vocal learning and associated brain areas in birds. PMID:23845108

System and method for chromatography and electrophoresis using circular optical scanning

DOEpatents

Balch, Joseph W.; Brewer, Laurence R.; Davidson, James C.; Kimbrough, Joseph R.

2001-01-01

A system and method is disclosed for chromatography and electrophoresis using circular optical scanning. One or more rectangular microchannel plates or radial microchannel plates has a set of analysis channels for insertion of molecular samples. One or more scanning devices repeatedly pass over the analysis channels in one direction at a predetermined rotational velocity and with a predetermined rotational radius. The rotational radius may be dynamically varied so as to monitor the molecular sample at various positions along a analysis channel. Sample loading robots may also be used to input molecular samples into the analysis channels. Radial microchannel plates are built from a substrate whose analysis channels are disposed at a non-parallel angle with respect to each other. A first step in the method accesses either a rectangular or radial microchannel plate, having a set of analysis channels, and second step passes a scanning device repeatedly in one direction over the analysis channels. As a third step, the scanning device is passed over the analysis channels at dynamically varying distances from a centerpoint of the scanning device. As a fourth step, molecular samples are loaded into the analysis channels with a robot.

Structural insights into the mechanism of activation of the TRPV1 channel by a membrane-bound tarantula toxin

PubMed Central

Bae, Chanhyung; Anselmi, Claudio; Kalia, Jeet; Jara-Oseguera, Andres; Schwieters, Charles D; Krepkiy, Dmitriy; Won Lee, Chul; Kim, Eun-Hee; Kim, Jae Il; Faraldo-Gómez, José D; Swartz, Kenton J

2016-01-01

Venom toxins are invaluable tools for exploring the structure and mechanisms of ion channels. Here, we solve the structure of double-knot toxin (DkTx), a tarantula toxin that activates the heat-activated TRPV1 channel. We also provide improved structures of TRPV1 with and without the toxin bound, and investigate the interactions of DkTx with the channel and membranes. We find that DkTx binds to the outer edge of the external pore of TRPV1 in a counterclockwise configuration, using a limited protein-protein interface and inserting hydrophobic residues into the bilayer. We also show that DkTx partitions naturally into membranes, with the two lobes exhibiting opposing energetics for membrane partitioning and channel activation. Finally, we find that the toxin disrupts a cluster of hydrophobic residues behind the selectivity filter that are critical for channel activation. Collectively, our findings reveal a novel mode of toxin-channel recognition that has important implications for the mechanism of thermosensation. DOI: http://dx.doi.org/10.7554/eLife.11273.001 PMID:26880553

Energy transduction and signal averaging of fluctuating electric fields by a single protein ion channel.

PubMed

Verdia-Baguena, C; Gomez, V; Cervera, J; Ramirez, P; Mafe, S

2016-12-21

We demonstrate the electrical rectification and signal averaging of fluctuating signals using a biological nanostructure in aqueous solution: a single protein ion channel inserted in the lipid bilayer characteristic of cell membranes. The conversion of oscillating, zero time-average potentials into directional currents permits charging of a load capacitor to significant steady-state voltages within a few minutes in the case of the outer membrane porin F (OmpF) protein, a bacterial channel of Escherichia coli. The experiments and simulations show signal averaging effects at a more fundamental level than the traditional cell and tissue scales, which are characterized by ensembles of many ion channels operating simultaneously. The results also suggest signal transduction schemes with bio-electronic interfaces and ionic circuits where soft matter nanodiodes can be coupled to conventional electronic elements.

Results for diffusion-weighted imaging with a fourth-channel gradient insert.

PubMed

Feldman, Rebecca E; Scholl, Timothy J; Alford, Jamu K; Handler, William B; Harris, Chad T; Chronik, Blaine A

2011-12-01

Diffusion-weighted imaging suffers from motion artifacts and relatively low signal quality due to the long echo times required to permit the diffusion encoding. We investigated the inclusion of a noncylindrical fourth gradient coil, dedicated entirely to diffusion encoding, into the imaging system. Standard three-axis whole body gradients were used during image acquisition, but we designed and constructed an insert coil to perform diffusion encodings. We imaged three phantoms on a 3-T system with a range of diffusion coefficients. Using the insert gradient, we were able to encode b values of greater than 1300 s/mm(2) with an echo time of just 83 ms. Images obtained using the insert gradient had higher signal to noise ratios than those obtained using the whole body gradient: at 500 s/mm(2) there was a 18% improvement in signal to noise ratio, at 1000 s/mm(2) there was a 39% improvement in signal to noise ratio, and at 1350 s/mm(2) there was a 56% improvement in signal to noise ratio. Using the insert gradient, we were capable of doing diffusion encoding at high b values by using relatively short echo times. Copyright © 2011 Wiley Periodicals, Inc.

High aspect ratio catalytic reactor and catalyst inserts therefor

DOEpatents

Lin, Jiefeng; Kelly, Sean M.

2018-04-10

The present invention relates to high efficient tubular catalytic steam reforming reactor configured from about 0.2 inch to about 2 inch inside diameter high temperature metal alloy tube or pipe and loaded with a plurality of rolled catalyst inserts comprising metallic monoliths. The catalyst insert substrate is formed from a single metal foil without a central supporting structure in the form of a spiral monolith. The single metal foil is treated to have 3-dimensional surface features that provide mechanical support and establish open gas channels between each of the rolled layers. This unique geometry accelerates gas mixing and heat transfer and provides a high catalytic active surface area. The small diameter, high aspect ratio tubular catalytic steam reforming reactors loaded with rolled catalyst inserts can be arranged in a multi-pass non-vertical parallel configuration thermally coupled with a heat source to carry out steam reforming of hydrocarbon-containing feeds. The rolled catalyst inserts are self-supported on the reactor wall and enable efficient heat transfer from the reactor wall to the reactor interior, and lower pressure drop than known particulate catalysts. The heat source can be oxygen transport membrane reactors.

Prospects of zero Schottky barrier height in a graphene-inserted MoS{sub 2}-metal interface

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

Chanana, Anuja; Mahapatra, Santanu

2016-01-07

A low Schottky barrier height (SBH) at source/drain contact is essential for achieving high drive current in atomic layer MoS{sub 2}-channel-based field effect transistors. Approaches such as choosing metals with appropriate work functions and chemical doping are employed previously to improve the carrier injection from the contact electrodes to the channel and to mitigate the SBH between the MoS{sub 2} and metal. Recent experiments demonstrate significant SBH reduction when graphene layer is inserted between metal slab (Ti and Ni) and MoS{sub 2}. However, the physical or chemical origin of this phenomenon is not yet clearly understood. In this work, densitymore » functional theory simulations are performed, employing pseudopotentials with very high basis sets to get insights of the charge transfer between metal and monolayer MoS{sub 2} through the inserted graphene layer. Our atomistic simulations on 16 different interfaces involving five different metals (Ti, Ag, Ru, Au, and Pt) reveal that (i) such a decrease in SBH is not consistent among various metals, rather an increase in SBH is observed in case of Au and Pt; (ii) unlike MoS{sub 2}-metal interface, the projected dispersion of MoS{sub 2} remains preserved in any MoS{sub 2}-graphene-metal system with shift in the bands on the energy axis. (iii) A proper choice of metal (e.g., Ru) may exhibit ohmic nature in a graphene-inserted MoS{sub 2}-metal contact. These understandings would provide a direction in developing high-performance transistors involving heteroatomic layers as contact electrodes.« less

Structure, Function, Self-Assembly and Origin of Simple Membrane Proteins

NASA Technical Reports Server (NTRS)

Pohorille, Andrew

2003-01-01

Integral membrane proteins perform such essential cellular functions as transport of ions, nutrients and waste products across cell walls, transduction of environmental signals, regulation of cell fusion, recognition of other cells, energy capture and its conversion into high-energy compounds. In fact, 30-40% of genes in modem organisms codes for membrane proteins. Although contemporary membrane proteins or their functional assemblies can be quite complex, their transmembrane fragments are usually remarkably simple. The most common structural motif for these fragments is a bundle of alpha-helices, but occasionally it could be a beta-barrel. In a series of molecular dynamics computer simulations we investigated self-organizing properties of simple membrane proteins based on these structural motifs. Specifically, we studied folding and insertion into membranes of short, nonpolar or amphiphatic peptides. We also investigated glycophorin A, a peptide that forms sequence-specific dimers, and a transmembrane aggregate of four identical alpha-helices that forms an efficient and selective voltage-gated proton channel was investigated. Many peptides are attracted to water-membrane interfaces. Once at the interface, nonpolar peptides spontaneously fold to a-helices. Whenever the sequence permits, peptides that contain both polar and nonpolar amino also adopt helical structures, in which polar and nonpolar amino acid side chains are immersed in water and membrane, respectively. Specific identity of side chains is less important. Helical peptides at the interface could insert into the membrane and adopt a transmembrane conformation. However, insertion of a single helix is unfavorable because polar groups in the peptide become completely dehydrated upon insertion. The unfavorable free energy of insertion can be regained by spontaneous association of peptides in the membrane. The first step in this process is the formation of dimers, although the most common are aggregates of 4-7 helices. The helices could arrange themselves such that they formed pores capable of transporting ions and small molecules across membranes. Stability of transmembrane aggregates of simple proteins is often only marginal and, therefore, it can be regulated by environmental signals or small sequence modifications in the region of interhelical interactions. A key step in the earliest evolution of membrane proteins was the emergence of selectivity for specific substrates. Many channels could become selective if one or only a few properly chosen amino acids are properly placed along the channel, acting as filters or gates. This is a convenient evolutionary solution because it does not require imposing conditions on the whole sequence.

European Immunology Congress (7th), Jerusalem, Israel.

DTIC Science & Technology

1985-11-22

Zan-Bar, Israel. glycoprotein hormone which plays a key tivity, and the authors postulated that immunoregulatory role by inducing ac- IL-2 may have a...the expres- tion relationship of this important im- sion of 33B31 receptors, slows down the . munoregulatory hormone . turnover of these receptors once...Israel) have been studying the stimula- stimulation with monoclonal anti-idio- tion of growth by an FCy receptor ex- typic antibodies against

Examining the effects of testwiseness in conceptual physics evaluations

NASA Astrophysics Data System (ADS)

DeVore, Seth; Stewart, John; Stewart, Gay

2016-12-01

Testwiseness is defined as the set of cognitive strategies used by a student that is intended to improve his or her score on a test regardless of the test's subject matter. Questions with elements that may be affected by testwiseness are common in physics assessments, even in those which have been extensively validated and widely used as evaluation tools in physics education research. The potential effect of several elements of testwiseness were analyzed for questions in the Force Concept Inventory (FCI) and Conceptual Survey on Electricity and Magnetism that contain distractors that are predicted to be influenced by testwiseness. This analysis was performed using data sets collected between fall 2001 and spring 2014 at one midwestern U.S. university (including over 9500 students) and between Spring 2011 and Spring 2015 at a second eastern U.S. university (including over 2500 students). Student avoidance of "none of the above" or "zero" distractors was statistically significant. The effect of the position of a distractor on its likelihood to be selected was also significant. The effects of several potential positive and negative testwiseness effects on student scores were also examined by developing two modified versions of the FCI designed to include additional elements related to testwiseness; testwiseness produced little effect post-instruction in student performance on the modified instruments.

Exciting Alfven Waves using Modulated Electron Heating by High Power Microwaves

NASA Astrophysics Data System (ADS)

Wang, Yuhou; Gekelman, Walter; Pribyl, Patrick; van Compernolle, Bart; Papadopoulos, Konstantinos

2014-10-01

Experiments exploring the physics of ionospheric modification with intense perpendicular propagating waves (k-> ⊥B->0) on the Large Plasma Device (LaPD) at UCLA have been upgraded with the addition of a high power rapidly pulsed microwave source. The plasma is irradiated with ten pulses (250 kW X-band) near the upper-hybrid frequency. The pulses are modulated at a frequency of a fraction (0.1-1.0) of fci (ion cyclotron frequency). Based on a previous single-pulse experiment, the modulated electron heating may drive a large amplitude shear Alfvén wave (f

Active Learning in the Physics Classroom

NASA Astrophysics Data System (ADS)

Naron, Carol

Many students enter physics classes filled with misconceptions about physics concepts. Students tend to retain these misconceptions into their adult lives, even after physics instruction. Constructivist researchers have found that students gain understanding through their experiences. Researchers have also found that active learning practices increase conceptual understanding of introductory physics students. This project study sought to examine whether incorporating active learning practices in an advanced placement physics classroom increased conceptual understanding as measured by the force concept inventory (FCI). Physics students at the study site were given the FCI as both a pre- and posttest. Test data were analyzed using two different methods---a repeated-measures t test and the Hake gain method. The results of this research project showed that test score gains were statistically significant, as measured by the t test. The Hake gain results indicated a low (22.5%) gain for the class. The resulting project was a curriculum plan for teaching the mechanics portion of Advanced Placement (AP) physics B as well as several active learning classroom practices supported by the research. This project will allow AP physics teachers an opportunity to improve their curricular practices. Locally, the results of this project study showed that research participants gained understanding of physics concepts. Social change may occur as teachers implement active learning strategies, thus creating improved student understanding of physics concepts.

Innovative Training of In-service Teachers for Active Learning: A Short Teacher Development Course Based on Physics Education Research

NASA Astrophysics Data System (ADS)

Zavala, Genaro; Alarcón, Hugo; Benegas, Julio

2007-08-01

In this contribution we describe a short development course for in-service physics teachers. The course structure and materials are based on the results of educational research, and its main objective is to provide in-service teachers with a first contact with the active learning strategy “Tutorials in Introductory Physics,” developed by the Physics Education Research Group at the University of Washington. The course was organized in a constructivist, active learning environment, so that teachers have first to experience, as regular students, the whole Tutorial sequence of activities: Tutorial pre-test, Tutorial, and Tutorial Homework. After each Tutorial, teachers reflect on, and recognize their own students’ learning difficulties, discussing their teaching experiences with their colleagues in small collaborative groups first and the whole class later. Finally they read and discuss specific Physics Education Research literature, where these learning difficulties have been extensively studied by researchers. At the beginning and at the end of the course the participants were given the conceptual multiple-choice test Force Concept Inventory (FCI). The pre-/post-instruction FCI data were presented as a practical example of the use of a research-based test widely used in educational research and in formative assessment processes designed to improve instruction.

Neuroprotective effect of mesenchymal stem cell through complement component 3 downregulation after transient focal cerebral ischemia in mice.

PubMed

Jung, Hye-Seon; Jeong, Si-Yeon; Yang, Jiwon; Kim, So-Dam; Zhang, Baojin; Yoo, Hyun Seung; Song, Sun U; Jeon, Myung-Shin; Song, Yun Seon

2016-10-28

Bone marrow-derived mesenchymal stem cells (MSCs) are used in stroke treatment despite the poor understanding of its mode of action. The immune suppressive and anti-inflammatory properties of MSCs possibly play important roles in regulating neuroinflammation after stroke. We investigated whether MSCs reduce the inflammatory complement component 3 (C3) levels, thus, providing neuroprotection during stroke. Mice were subjected to transient focal cerebral ischemia (tFCI), after which MSCs were intravenously injected. The infarct volume of the brain was reduced in MSC-injected tFCI mice, and C3 expression was significantly reduced in both the brain and the blood. Additionally, the profiles of other inflammatory mediators demonstrated neuroprotective changes in the MSCs-treated group. In order to analyze the effect of MSCs on neurons during cerebral ischemia, primary cortical neurons were co-cultured with MSCs under oxygen-glucose deprivation (OGD). Primary neurons co-cultured with MSCs exhibited reduced levels of C3 expression and increased protection against OGD, indicating that treatment with MSCs reduces excessive C3 expression and rescues ischemia-induced neuronal damage. Our finding suggests that reduction of C3 expression by MSCs can help to ameliorate ischemic brain damage, offering a new neuroprotective strategy in stroke therapy. Copyright © 2016. Published by Elsevier Ireland Ltd.

Prevalence and co-occurrence of hip dysplasia and elbow dysplasia in Dutch pure-bred dogs.

PubMed

Lavrijsen, I C M; Heuven, H C M; Meij, B P; Theyse, L F H; Nap, R C; Leegwater, P A J; Hazewinkel, H A W

2014-05-01

Hip as well as elbow dysplasia (HD, ED) are developmental disorders leading to malformation of their respective joints. For a long time both disorders have been scored and targeted for improvement using selective breeding in several Dutch dog populations. In this paper all scores for both HD and ED, given to pure bred dogs in the Netherlands from 2002 to 2010, were analyzed. Heritabilities and correlations between HD and ED were calculated for the 4 most frequently scored breeds. Heritabilities ranged from 0.0 to 0.37 for HD related traits (FCI-score, osteoarthritis, congruity, shape and laxity (Norberg angle); FCI: Fédération Cynologique Internationale) and from 0.0 to 0.39 for ED related traits (IEWG score, osteoarthritis, sclerosis and indentation; IEWG: International Elbow Working Group). HD related traits showed high genetic and residual correlations among each other but were only to a minor extent correlated with ED related traits, which also showed high correlations among each other. Genetic correlations were higher than residual correlations. Phenotypic and genetic trends since 2001 for the four most scored breeds were slightly positive but decreasing over time, indicating that selection over the past decade has not been effective. Copyright © 2014. Published by Elsevier B.V.

Effect of inclusion or non-inclusion of short lactations and cow and/or dam genetic group on genetic evaluation of Girolando dairy cattle.

PubMed

Canaza-Cayo, A W; Silva, M V G B; Cobuci, J A; Martins, M F; Lopes, P S

2016-04-04

The objective of this study was to evaluate the effects of inclusion or non-inclusion of short lactations and cow (CGG) and/or dam (DGG) genetic group on the genetic evaluation of 305-day milk yield (MY305), age at first calving (AFC), and first calving interval (FCI) of Girolando cows. Covariance components were estimated by the restricted maximum likelihood method in an animal model of single trait analyses. The heritability estimates for MY305, AFC, and FCI ranged from 0.23 to 0.29, 0.40 to 0.44, and 0.13 to 0.14, respectively, when short lactations were not included, and from 0.23 to 0.28, 0.39 to 0.43, and 0.13 to 0.14, respectively, when short lactations were included. The inclusion of short lactations caused little variation in the variance components and heritability estimates of traits, but their non-inclusion resulted in the re-ranking of animals. Models with CGG or DGG fixed effects had higher heritability estimates for all traits compared with models that consider these two effects simultaneously. We recommend using the model with fixed effects of CGG and inclusion of short lactations for the genetic evaluation of Girolando cattle.

Reduced-rank technique for joint channel estimation in TD-SCDMA systems

NASA Astrophysics Data System (ADS)

Kamil Marzook, Ali; Ismail, Alyani; Mohd Ali, Borhanuddin; Sali, Adawati; Khatun, Sabira

2013-02-01

In time division-synchronous code division multiple access systems, increasing the system capacity by exploiting the inserting of the largest number of users in one time slot (TS) requires adding more estimation processes to estimate the joint channel matrix for the whole system. The increase in the number of channel parameters due the increase in the number of users in one TS directly affects the precision of the estimator's performance. This article presents a novel channel estimation with low complexity, which relies on reducing the rank order of the total channel matrix H. The proposed method exploits the rank deficiency of H to reduce the number of parameters that characterise this matrix. The adopted reduced-rank technique is based on truncated singular value decomposition algorithm. The algorithms for reduced-rank joint channel estimation (JCE) are derived and compared against traditional full-rank JCEs: least squares (LS) or Steiner and enhanced (LS or MMSE) algorithms. Simulation results of the normalised mean square error showed the superiority of reduced-rank estimators. In addition, the channel impulse responses founded by reduced-rank estimator for all active users offers considerable performance improvement over the conventional estimator along the channel window length.

Trap seal for open circuit liquid cooled turbines

DOEpatents

Grondahl, Clayton M.; Germain, Malcolm R.

1980-01-01

An improved trap seal for open circuit liquid cooled turbines is disclosed. The trap seal of the present invention includes an annular recess formed in the supply conduit of cooling channels formed in the airfoil of the turbine buckets. A cylindrical insert is located in the annular recesses and has a plurality of axial grooves formed along the outer periphery thereof and a central recess formed in one end thereof. The axial grooves and central recess formed in the cylindrical insert cooperate with the annular recess to define a plurality of S-shaped trap seals which permit the passage of liquid coolant but prohibit passage of gaseous coolant.

Fluorescence detection of the movement of single KcsA subunits reveals cooperativity

PubMed Central

Blunck, Rikard; McGuire, Hugo; Hyde, H. Clark; Bezanilla, Francisco

2008-01-01

The prokaryotic KcsA channel is gated at the helical bundle crossing by intracellular protons and inactivates at the extracellular selectivity filter. The C-terminal transmembrane helix has to undergo a conformational change for potassium ions to access the central cavity. Whereas a partial opening of the tetrameric channel is suggested to be responsible for subconductance levels of ion channels, including KcsA, a cooperative opening of the 4 subunits is postulated as the final opening step. In this study, we used single-channel fluorescence spectroscopy of KcsA to directly observe the movement of each subunit and the temporal correlation between subunits. Purified KcsA channels labeled at the C terminus near the bundle crossing have been inserted into supported lipid bilayer, and the fluorescence traces analyzed by means of a cooperative or independent Markov model. The analysis revealed that the 4 subunits do not move fully independently but instead showed a certain degree of cooperativity. However, the 4 subunits do not simply open in 1 concerted step. PMID:19074286

Thermodynamic study of benzocaine insertion into different lipid bilayers

NASA Astrophysics Data System (ADS)

Cascales, J. J. López; Costa, S. D. Oliveira; Porasso, R. D.

2011-10-01

Despite the general consensus concerning the role played by sodium channels in the molecular mechanism of local anesthetics, the potency of anaesthetic drugs also seems to be related with their solubility in lipid bilayers. In this respect, this work represents a thermodynamic study of benzocaine insertion into lipid bilayers of different compositions by means of molecular dynamics simulation. Thus, the free energy profiles associated with benzocaine insertion into symmetric lipid bilayers composed of different proportions of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylserine were studied. From the simulation results, a maximum in the free energy (ΔG) profile was measured in the region of the lipid/solution interface. This free energy barrier appears to be very much dependent on the lipid composition of the membrane. On the other hand, the minimum free energy (ΔG) within the bilayer remained almost independent of the lipid composition of the bilayer. By repeating the study at different temperatures, it was seen how the spontaneity of benzocaine insertion into the lipid bilayer is due to an increase in the entropy associated with the process.

Thermodynamic study of benzocaine insertion into different lipid bilayers.

PubMed

Cascales, J J López; Costa, S D Oliveira; Porasso, R D

2011-10-07

Despite the general consensus concerning the role played by sodium channels in the molecular mechanism of local anesthetics, the potency of anaesthetic drugs also seems to be related with their solubility in lipid bilayers. In this respect, this work represents a thermodynamic study of benzocaine insertion into lipid bilayers of different compositions by means of molecular dynamics simulation. Thus, the free energy profiles associated with benzocaine insertion into symmetric lipid bilayers composed of different proportions of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylserine were studied. From the simulation results, a maximum in the free energy (ΔG) profile was measured in the region of the lipid/solution interface. This free energy barrier appears to be very much dependent on the lipid composition of the membrane. On the other hand, the minimum free energy (ΔG) within the bilayer remained almost independent of the lipid composition of the bilayer. By repeating the study at different temperatures, it was seen how the spontaneity of benzocaine insertion into the lipid bilayer is due to an increase in the entropy associated with the process. © 2011 American Institute of Physics

Turbulence scaling study in an MHD wind tunnel on the Swarthmore Spheromak Experiment

NASA Astrophysics Data System (ADS)

Schaffner, D. A.; Wan, A.; Owusu-Boateng, J.; Brown, M. R.; Lukin, V. S.

2013-10-01

The turbulence of colliding spheromaks are explored in the MHD wind tunnel on the SSX. Fully ionized hydrogen plasma is produced by two plasma guns on opposite sides of a 1 m by 15 cm copper cylinder. Modification of B-field, Ti and β are made through stuffing flux variation of the plasma guns. Presented here are turbulent f-/ k-spectra and correlation times/lengths of B-field fluctuations as measured by a 16 channel B-dot radial probe array at the chamber midplane. Power-law fits to spectra show scaling that is robust to changes in stuffing flux; fits are on the order of f-3 and k - 2 . 1 for all flux variations. Dissipation range modification of the spectra is observed; changes to the f-spectra slopes occur around f =fci while changes in k-spectra slopes appear around ~ 5ρi . Dissipation range fits are made with an exponentially modified power-law model [Terry et al., PoP 2012]. Fluctuations in axial velocity are made using a Mach probe. Both B-field and velocity fluctuations persist on the same timescale in these experiments. Mach velocity f-spectra show power-laws similar to that for B-field. Comparison of spectra from MHD and Hall MHD simulations of SSX performed within the HiFi modeling framework are made to the experimental results.

Design and fabrication of pHEMT MMIC switches for IEEE 802.11.a/b/g WLAN applications

NASA Astrophysics Data System (ADS)

Mun, Jae Kyoung; Ji, Hong Gu; Ahn, Hyokyun; Kim, Haecheon; Park, Chong-Ook

2005-08-01

In this paper, we propose a channel structure for a promising switch pHEMT with excellent isolation characteristics based on the distribution of electric field intensity beneath the Schottky contact in the transistor. Using the proposed device channel structure, SPST and SPDT switches were designed and fabricated, applicable to 2.4 GHz and 5.8 GHz WLAN systems. We discuss the relationship between dc characteristics and switch parameters in this paper in detail. The developed SPST switch exhibits a low insertion loss of 0.26 dB and a high isolation of 34.3 dB with a control voltage of 0 V/-3 V at 5.8 GHz. The SPDT also shows a good performance of 0.85 dB insertion loss and 31.5 dB isolation under the same conditions. The measured power-handling capability at 2.4 GHz reveals that the SPDT has an output power of 27 dBm at the 1 dB compression point and a third-order intercept point of more than 46 dBm.

A novel frequency analysis method for assessing K(ir)2.1 and Na (v)1.5 currents.

PubMed

Rigby, J R; Poelzing, S

2012-04-01

Voltage clamping is an important tool for measuring individual currents from an electrically active cell. However, it is difficult to isolate individual currents without pharmacological or voltage inhibition. Herein, we present a technique that involves inserting a noise function into a standard voltage step protocol, which allows one to characterize the unique frequency response of an ion channel at different step potentials. Specifically, we compute the fast Fourier transform for a family of current traces at different step potentials for the inward rectifying potassium channel, K(ir)2.1, and the channel encoding the cardiac fast sodium current, Na(v)1.5. Each individual frequency magnitude, as a function of voltage step, is correlated to the peak current produced by each channel. The correlation coefficient vs. frequency relationship reveals that these two channels are associated with some unique frequencies with high absolute correlation. The individual IV relationship can then be recreated using only the unique frequencies with magnitudes of high absolute correlation. Thus, this study demonstrates that ion channels may exhibit unique frequency responses.

Molecular dissection of botulinum neurotoxin reveals interdomain chaperone function.

PubMed

Fischer, Audrey; Montal, Mauricio

2013-12-01

Clostridium botulinum neurotoxin (BoNT) is a multi-domain protein made up of the approximately 100 kDa heavy chain (HC) and the approximately 50 kDa light chain (LC). The HC can be further subdivided into two halves: the N-terminal translocation domain (TD) and the C-terminal Receptor Binding Domain (RBD). We have investigated the minimal requirements for channel activity and LC translocation. We utilize a cellular protection assay and a single channel/single molecule LC translocation assay to characterize in real time the channel and chaperone activities of BoNT/A truncation constructs in Neuro 2A cells. The unstructured, elongated belt region of the TD is demonstrated to be dispensable for channel activity, although may be required for productive LC translocation. We show that the RBD is not necessary for channel activity or LC translocation, however it dictates the pH threshold of channel insertion into the membrane. These findings indicate that each domain functions as a chaperone for the others in addition to their individual functions, working in concert to achieve productive intoxication. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tackling sun intrusion: a challenge of close collaboration of thermal, mechanical, structural and optical engineers

NASA Astrophysics Data System (ADS)

Kroneberger, Monika; Calleri, Andrea; Ulfers, Hendrik; Klossek, Andreas; Goepel, Michael

2017-09-01

The Meteosat Third Generation (MTG) program will ensure the continuity and enhancement of meteorological data from geostationary orbit as currently provided by the Meteosat Second Generation (MSG) system. OHB-Munich, as part of the core team consortium of the industrial prime contractor for the space segment Thales Alenia Space (France), is responsible for the Flexible Combined Imager - Telescope Assembly (FCI-TA) as well as the Infrared Sounder (IRS).

Physiology and pathophysiology of ClC-K/barttin channels.

PubMed

Fahlke, Christoph; Fischer, Martin

2010-01-01

ClC-K channels form a subgroup of anion channels within the ClC family of anion transport proteins. They are expressed predominantly in the kidney and in the inner ear, and are necessary for NaCl resorption in the loop of Henle and for K+ secretion by the stria vascularis. Subcellular distribution as well as the function of these channels are tightly regulated by an accessory subunit, barttin. Barttin improves the stability of ClC-K channel protein, stimulates the exit from the endoplasmic reticulum and insertion into the plasma membrane and changes its function by modifying voltage-dependent gating processes. The importance of ClC-K/barttin channels is highlighted by several genetic diseases. Dysfunctions of ClC-K channels result in Bartter syndrome, an inherited human condition characterized by impaired urinary concentration. Mutations in the gene encoding barttin, BSND, affect the urinary concentration as well as the sensory function of the inner ear. Surprisingly, there is one BSND mutation that causes deafness without affecting renal function, indicating that kidney function tolerates a reduction of anion channel activity that is not sufficient to support normal signal transduction in inner hair cells. This review summarizes recent work on molecular mechanisms, physiology, and pathophysiology of ClC-K/barttin channels.

Tubular Unimolecular Transmembrane Channels: Construction Strategy and Transport Activities.

PubMed

Si, Wen; Xin, Pengyang; Li, Zhan-Ting; Hou, Jun-Li

2015-06-16

Lipid bilayer membranes separate living cells from their environment. Membrane proteins are responsible for the processing of ion and molecular inputs and exports, sensing stimuli and signals across the bilayers, which may operate in a channel or carrier mechanism. Inspired by these wide-ranging functions of membrane proteins, chemists have made great efforts in constructing synthetic mimics in order to understand the transport mechanisms, create materials for separation, and develop therapeutic agents. Since the report of an alkylated cyclodextrin for transporting Cu(2+) and Co(2+) by Tabushi and co-workers in 1982, chemists have constructed a variety of artificial transmembrane channels by making use of either the multimolecular self-assembly or unimolecular strategy. In the context of the design of unimolecular channels, important advances have been made, including, among others, the tethering of natural gramicidin A or alamethicin and the modification of various macrocycles such as crown ethers, cyclodextrins, calixarenes, and cucurbiturils. Many of these unimolecular channels exhibit high transport ability for metal ions, particularly K(+) and Na(+). Concerning the development of artificial channels based on macrocyclic frameworks, one straightforward and efficient approach is to introduce discrete chains to reinforce their capability to insert into bilayers. Currently, this approach has found the widest applications in the systems of crown ethers and calixarenes. We envisioned that for macrocycle-based unimolecular channels, control of the arrangement of the appended chains in the upward and/or downward direction would favor the insertion of the molecular systems into bilayers, while the introduction of additional interactions among the chains would further stabilize a tubular conformation. Both factors should be helpful for the formation of new efficient channels. In this Account, we discuss our efforts in designing new unimolecular artificial channels from tubular pillar[n]arenes by extending their lengths with various ester, hydrazide, and short peptide chains. We have utilized well-defined pillar[5]arene and pillar[6]arene as rigid frameworks that allow the appended chains to afford extended tubular structures. We demonstrate that the hydrazide and peptide chains form intramolecular N-H···O═C hydrogen bonds that enhance the tubular conformation of the whole molecule. The new pillar[n]arene derivatives have been successfully applied as unimolecular channels for the selective transport of protons, water, and amino acids and the voltage-gated transport of K(+). We also show that aromatic hydrazide helices and macrocycles appended with peptide chains are able to mediate the selective transport of NH4(+).

In vitro performance and fracture resistance of CAD/CAM-fabricated implant supported molar crowns.

PubMed

Rosentritt, Martin; Hahnel, Sebastian; Engelhardt, Frank; Behr, Michael; Preis, Verena

2017-05-01

The aim of this study is to investigate the performance and fracture resistance of different CAD/CAM ceramic and composite materials as implant- or tooth-supported single crowns with respect to the clinical procedure (screwed/bonded restoration). One hundred twenty crowns were fabricated on implants or human molar teeth simulating (a) chairside procedure ([CHAIR] implant crown bonded to abutment), (b) labside procedure ([LAB] abutment and implant crown bonded in laboratory, screwed chairside), and (c) reference ([TOOTH] crowns luted on human teeth). Four materials were investigated: ZLS (zirconia-reinforced lithium silicate ceramic; Celtra Duo, Degudent: polished (P)/crystallized (C)), RB (resin-based composite; Cerasmart, GC), and RIC (resin-infiltrated ceramic; Enamic, Vita-Zahnfabrik). LiS (lithiumdisilicate; Emax CAD, Ivoclar-Vivadent) served as reference. Combined thermal cycling and mechanical loading (TCML) was performed simulating a 5-year clinical situation. Fracture force was determined. Data were statistically analyzed (Kolmogorov-Smirnov test, one-way ANOVA; post hoc Bonferroni, α = 0.05). One crown of ZLS_C[LAB] (1,200,000 cycles) and RB[CHAIR] (890 cycles) failed during TCML. Fracture values varied between 977.7 N(RB) and 3070.4 N(LiS)[CHAIR], 1130.6 N(RB) and 2998.1 N(LiS)[LAB], and 1802.4 N(ZLS) and 2664.3 N(LiS)[TOOTH]. Significantly (p < 0.003) different forces were found between the materials in all three groups. ZLS_C, RIC, and RB showed significantly (p < 0.014) different values for the individual groups. Partly ceramic and resin-based materials performed differently on implant or tooth abutments. The insertion of a screw channel reduced the stability for individual crown materials. Insertion of the screw channel should be performed carefully. All restorations were in a range where clinical application seems not restricted, but insertion of a screw channel might reduce stability of individual materials.

High-resolution orientation and depth of insertion of the voltage-sensing S4 helix of a potassium channel in lipid bilayers.

PubMed

Doherty, Tim; Su, Yongchao; Hong, Mei

2010-08-27

The opening and closing of voltage-gated potassium (Kv) channels are controlled by several conserved Arg residues in the S4 helix of the voltage-sensing domain. The interaction of these positively charged Arg residues with the lipid membrane has been of intense interest for understanding how membrane proteins fold to allow charged residues to insert into lipid bilayers against free-energy barriers. Using solid-state NMR, we have now determined the orientation and insertion depth of the S4 peptide of the KvAP channel in lipid bilayers. Two-dimensional (15)N correlation experiments of macroscopically oriented S4 peptide in phospholipid bilayers revealed a tilt angle of 40 degrees and two possible rotation angles differing by 180 degrees around the helix axis. Remarkably, the tilt angle and one of the two rotation angles are identical to those of the S4 helix in the intact voltage-sensing domain, suggesting that interactions between the S4 segment and other helices of the voltage-sensing domain are not essential for the membrane topology of the S4 helix. (13)C-(31)P distances between the S4 backbone and the lipid (31)P indicate a approximately 9 A local thinning and 2 A average thinning of the DMPC (1,2-dimyristoyl-sn-glycero-3-phosphochloline)/DMPG (1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol) bilayer, consistent with neutron diffraction data. Moreover, a short distance of 4.6 A from the guanidinium C(zeta) of the second Arg to (31)P indicates the existence of guanidinium phosphate hydrogen bonding and salt bridges. These data suggest that the structure of the Kv gating helix is mainly determined by protein-lipid interactions instead of interhelical protein-protein interactions, and the S4 amino acid sequence encodes sufficient information for the membrane topology of this crucial gating helix. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Nano-oxide-layer insertion and specular effects in spin valves: Experiment and theory

NASA Astrophysics Data System (ADS)

Wang, L.; Qiu, J. J.; McMahon, W. J.; Li, K. B.; Wu, Y. H.

2004-06-01

We report a systematic study of NOL (nano-oxide-layer) insertion and specular effects on the giant magnetoresistance (GMR) of single, synthetic, and dual spin valves, using a semiclassical Boltzmann theory. It is confirmed that the GMR ratio is enhanced by NOL insertion inside the pinned layer or after the free layer. The enhancements are primarily due to the contribution of the majority carriers. The NOL insertions inside the inactive layers of spin valves such as the seed, under, and capping layers reduce the GMR ratio. Though introducing a NOL before or after the Cu spacer would, in principle, significantly suppress the GMR ratio due to the blocking effect or the average effect of different spin channels, large positive or negative (inverse) GMR is found by assuming spin-dependent NOL specular reflections. We have also demonstrated that specular reflection, even beyond a capping layer, may result in reduction of GMR. Upon appropriate NOL insertion, the amplitude of curve of GMR versus thickness of individual layer of spin valves may be generally enhanced, but the shape may change, depending on whether the distance of the NOL to the layer is small or large (distance effect). Finally, it is found that most results obtained for the single realistic spin valves are applicable to synthetic and dual spin valves.

Computer Modeling of Protocellular Functions: Peptide Insertion in Membranes

NASA Technical Reports Server (NTRS)

Rodriquez-Gomez, D.; Darve, E.; Pohorille, A.

2006-01-01

Lipid vesicles became the precursors to protocells by acquiring the capabilities needed to survive and reproduce. These include transport of ions, nutrients and waste products across cell walls and capture of energy and its conversion into a chemically usable form. In modem organisms these functions are carried out by membrane-bound proteins (about 30% of the genome codes for this kind of proteins). A number of properties of alpha-helical peptides suggest that their associations are excellent candidates for protobiological precursors of proteins. In particular, some simple a-helical peptides can aggregate spontaneously and form functional channels. This process can be described conceptually by a three-step thermodynamic cycle: 1 - folding of helices at the water-membrane interface, 2 - helix insertion into the lipid bilayer and 3 - specific interactions of these helices that result in functional tertiary structures. Although a crucial step, helix insertion has not been adequately studied because of the insolubility and aggregation of hydrophobic peptides. In this work, we use computer simulation methods (Molecular Dynamics) to characterize the energetics of helix insertion and we discuss its importance in an evolutionary context. Specifically, helices could self-assemble only if their interactions were sufficiently strong to compensate the unfavorable Free Energy of insertion of individual helices into membranes, providing a selection mechanism for protobiological evolution.

Dual-channel operation in a synchronously pumped optical parametric oscillator for the generation of broadband mid-infrared coherent light sources.

PubMed

Liu, Pei; Wang, Sicong; He, Puyuan; Zhang, Zhaowei

2018-05-01

We report, to the best of our knowledge, a novel approach for generating broadband mid-infrared (mid-IR) light by implementing a dual-channel scheme in a synchronously pumped optical parametric oscillator (SPOPO). Two-channel operation was achieved by inserting a prism pair and two reflection mirrors inside an optical parametric oscillator (OPO) cavity. Pumped by a Yb-fiber laser, the OPO generated an idler wave at ∼3150  nm with a -10  dB bandwidth of ∼13.2  THz, which was twice as much as that of the pump source. This scheme represents a promising technical route to transform conventional SPOPOs into a device capable of generating mid-IR light with very broad instantaneous bandwidth.

Secondary implementation of interactive engagement teaching techniques: Choices and challenges in a Gulf Arab context

NASA Astrophysics Data System (ADS)

Hitt, G. W.; Isakovic, A. F.; Fawwaz, O.; Bawa'aneh, M. S.; El-Kork, N.; Makkiyil, S.; Qattan, I. A.

2014-12-01

We report on efforts to design the "Collaborative Workshop Physics" (CWP) instructional strategy to deliver the first interactive engagement (IE) physics course at Khalifa University of Science, Technology and Research (KU), United Arab Emirates (UAE). To our knowledge, this work reports the first calculus-based, introductory mechanics course on the Arabian Peninsula using physics education research (PER)-based instruction. A brief history and present context of general university and STEM teaching in the UAE is given. We present this secondary implementation (SI) as a case study of a novel context and use it to determine if PER-based instruction can be successfully implemented far from the cultural context of the primary developer and, if so, how might such SIs differ from SIs within the United States (U.S.) in terms of criteria for and risks to their success. With these questions in view, a prereform baseline comprised of Maryland Physics Expectations in Physics survey, Force Concept Inventory (FCI), course exam grades, and English language proficiency data are used to design a hybrid implementation of Cooperative Group Problem Solving. We find that for students with high English proficiency, normalized gain on FCI improves substantially, from ⟨g⟩=0.16±0.10 prereform to ⟨g⟩=0.47±0.08 in the CWP pilot (standard errors), indicating a successful SI. However, we also find evidence that normalized gains on FCI are strongly modulated by language proficiency and discuss likely causes. Regardless of language ability, problem-solving skill is also substantially improved and course drop-fail-withdrawal rates are cut from 50% to 24%. In particular, we find evidence in postreform student interviews that prior classroom experiences, and not broader cultural expectations about education, are the more significant cause of expectations that are at odds with the classroom norms of well-functioning PER-based instruction. We present this result as evidence that PER-based innovations can be implemented across great changes in cultural context, provided that the method is thoughtfully adapted in anticipation of context and culture-specific student expectations. This case study should be valuable for future reforms at KU, the broader Gulf region, and other institutions facing similar challenges involving SI of PER-based instruction outside the U.S.

STIM1 converts TRPC1 from a receptor-operated to a store-operated channel: moving TRPC1 in and out of lipid rafts.

PubMed

Alicia, Sampieri; Angélica, Zepeda; Carlos, Saldaña; Alfonso, Salgado; Vaca, Luis

2008-11-01

While the role of members from the TRPC family of channels as receptor-operated channels (ROC) is well established and supported by numerous studies, the role of this family of channels as store-operated channels (SOC) has been the focus of a heated controversy over the last few years. In the present study, we have explored the modulation of STIM1 on human TRPC1 channel. We show that the association of STIM1 to TRPC1 favors the insertion of TRPC1 into lipid rafts, where TRPC1 functions as a SOC. In the absence of STIM1, TRPC1 associates to other members from the TRPC family of channels to form ROCs. A novel TIRFM-FRET method illustrates the relevance of the dynamic association between STIM1 and TRPC1 for the activation of SOC and the lipid raft localization of the STIM1-TRPC1 complex. This study provides new evidence about the dual activity of TRPC1 (forming ROC or SOC) and the partners needed to determine TRPC1 functional fate. It highlights also the role of plasma membrane microdomains and ER-PM junctions in modulating TRPC1 channel function and its association to STIM1.

26. Detail, typical section of roof; note condition of slates, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. Detail, typical section of roof; note condition of slates, missing slates replaced by sheet metal inserts, heavy moss growth on lower edges of slates and completely filling channel of remaining gutter section; view to southwest from lift-bed truck, 135mm lens. - Southern Pacific Depot, 559 El Camino Real, San Carlos, San Mateo County, CA

Force Balance Allocation Model

DTIC Science & Technology

1982-11-19

1 53V jiAiA 2 400 , I,4 v 1 fCI A., 𔃺. " 3,. 54 QVA fA 8,1...Virginia 22209 19 November 1982 Technical Report CONTRACT No. DNA 001-82-C-0283 C’ APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. N" . 1 ’ CI" THIS...JAN 1 2 1984 DEFENSE NUCLEAR AGENCY Washington, DC 20305 ’-’C *" ’ . . . • mw Destroy this report when it is no longer needed. Do not return to

Generation of Shear Alfvén Waves by Repetitive High Power Microwave Pulses Near the Electron Plasma Frequency - A laboratory study of a ``Virtual Antenna''

NASA Astrophysics Data System (ADS)

Wang, Yuhou; Gekelman, Walter; Pribyl, Patrick; van Compernolle, Bart; Papadopoulos, Konstantinos

2015-11-01

ELF / ULF waves are important in terrestrial radio communications but difficult to launch using ground-based structures due to their enormous wavelengths. In spite of this generation of such waves by field-aligned ionospheric heating modulation was first demonstrated using the HAARP facility. In the future heaters near the equator will be constructed and laboratory experiments on cross-field wave propagation could be key to the program's success. Here we report a detailed laboratory study conducted on the Large Plasma Device (LaPD) at UCLA. In this experiment, ten rapid pulses of high power microwaves (250 kW X-band) near the plasma frequency were launched transverse to the background field, and were modulated at a variable fraction (0.1-1.0) of fci. Along with bulk electron heating and density modification, the microwave pulses generated a population of fast electrons. The field-aligned current carried by the fast electrons acted as an antenna that radiated shear Alfvén waves. It was demonstrated that a controllable arbitrary frequency (f

On ancestors of dog breeds with focus on Weimaraner hunting dogs.

PubMed

Kropatsch, R; Streitberger, K; Schulte-Middelmann, T; Dekomien, G; Epplen, J T

2011-02-01

Paternally inherited Y chromosomal markers and maternally inherited mitochondrial (mt) DNA sequences were investigated in 27 dog breeds (Canis familiaris), of which the Weimaraner hunting dog was studied in greater detail. Altogether, nine potentially polymorphic markers of the Y chromosome were examined as well as parts of the canine mt genome (1947 base pairs) in 111 male dogs and four wolves for comparison. Twenty Y chromosomal and fifty-nine mitochondrial DNA (mtDNA) haplotypes were identified in the canine breeds and wolves. In 34 Weimaraners, four distinct Y chromosomal haplotypes were observed as well as three mtDNA types thus reflecting at least four male and three female ancestors for the current population in Germany. Tracing patri- and matrilineages, several entries in the Weimaraner stud book cannot be reconciled with the male-only, Y chromosomal neither the female-only, mt inheritance patterns, respectively. The investigated breeds represent 9 of 10 groups defined by the Fédération Cynologique Internationale (FCI). The level of Y chromosomal and especially mtDNA diversity was immense considering the relatively small number of individuals investigated per breed. Unique haplotypes were found only in a few breeds and the wolf. Other haplotypes were shared among several breeds, also across different FCI groups, suggesting that these canine breeds had common male and female ancestors. © 2010 Blackwell Verlag GmbH.

Natural and technical factors in faecal contamination incidents of drinking water in small distribution networks, France, 2003-2004: a geographical study.

PubMed

Beaudeau, Pascal; Valdes, Danièle; Mouly, Damien; Stempfelet, Morgane; Seux, René

2010-03-01

This geographical study aimed to show natural or water-processing-related factors of faecal contamination incidents (FCIs) of drinking water in continental France. We defined a FCI as the occurrence of at least 20 colony-forming Escherichia coli or enterococci among all the 100 mL samples collected for regulatory purpose within one day from a given drinking water supply zone (SZ). We explored correlations between the standardized number of FCIs per département (N_Pols) and various indicators related to weather, land cover, topography, geology and water management for three SZ size sub-classes. In 2003-2004, 2,739 FCIs occurred in SZs supplying fewer than 2,000 people, mainly with simply disinfected groundwater. N_Pols correlates with four covariates: (1) precipitation; (2) the extension of the karst outcrops; (3) the extent of disinfection; and (4) catchment protection. One hundred millimetres of yearly excess in precipitation increases the pollution risk by 28-37%, depending on the sub-class. A 10% extension of the karst areas, a 10% increase of unprotected resources, or of SZs with no disinfection, could entail a higher risk of FCI by about 10%. The correlations are reproducible over the three sub-classes and corroborate expert appraisals. These results encourage the ongoing effort to generalize disinfection and catchment protection.

Reconstitution of a Kv channel into lipid membranes for structural and functional studies.

PubMed

Lee, Sungsoo; Zheng, Hui; Shi, Liang; Jiang, Qiu-Xing

2013-07-13

To study the lipid-protein interaction in a reductionistic fashion, it is necessary to incorporate the membrane proteins into membranes of well-defined lipid composition. We are studying the lipid-dependent gating effects in a prototype voltage-gated potassium (Kv) channel, and have worked out detailed procedures to reconstitute the channels into different membrane systems. Our reconstitution procedures take consideration of both detergent-induced fusion of vesicles and the fusion of protein/detergent micelles with the lipid/detergent mixed micelles as well as the importance of reaching an equilibrium distribution of lipids among the protein/detergent/lipid and the detergent/lipid mixed micelles. Our data suggested that the insertion of the channels in the lipid vesicles is relatively random in orientations, and the reconstitution efficiency is so high that no detectable protein aggregates were seen in fractionation experiments. We have utilized the reconstituted channels to determine the conformational states of the channels in different lipids, record electrical activities of a small number of channels incorporated in planar lipid bilayers, screen for conformation-specific ligands from a phage-displayed peptide library, and support the growth of 2D crystals of the channels in membranes. The reconstitution procedures described here may be adapted for studying other membrane proteins in lipid bilayers, especially for the investigation of the lipid effects on the eukaryotic voltage-gated ion channels.

An algorithm for direct causal learning of influences on patient outcomes.

PubMed

Rathnam, Chandramouli; Lee, Sanghoon; Jiang, Xia

2017-01-01

This study aims at developing and introducing a new algorithm, called direct causal learner (DCL), for learning the direct causal influences of a single target. We applied it to both simulated and real clinical and genome wide association study (GWAS) datasets and compared its performance to classic causal learning algorithms. The DCL algorithm learns the causes of a single target from passive data using Bayesian-scoring, instead of using independence checks, and a novel deletion algorithm. We generate 14,400 simulated datasets and measure the number of datasets for which DCL correctly and partially predicts the direct causes. We then compare its performance with the constraint-based path consistency (PC) and conservative PC (CPC) algorithms, the Bayesian-score based fast greedy search (FGS) algorithm, and the partial ancestral graphs algorithm fast causal inference (FCI). In addition, we extend our comparison of all five algorithms to both a real GWAS dataset and real breast cancer datasets over various time-points in order to observe how effective they are at predicting the causal influences of Alzheimer's disease and breast cancer survival. DCL consistently outperforms FGS, PC, CPC, and FCI in discovering the parents of the target for the datasets simulated using a simple network. Overall, DCL predicts significantly more datasets correctly (McNemar's test significance: p<0.0001) than any of the other algorithms for these network types. For example, when assessing overall performance (simple and complex network results combined), DCL correctly predicts approximately 1400 more datasets than the top FGS method, 1600 more datasets than the top CPC method, 4500 more datasets than the top PC method, and 5600 more datasets than the top FCI method. Although FGS did correctly predict more datasets than DCL for the complex networks, and DCL correctly predicted only a few more datasets than CPC for these networks, there is no significant difference in performance between these three algorithms for this network type. However, when we use a more continuous measure of accuracy, we find that all the DCL methods are able to better partially predict more direct causes than FGS and CPC for the complex networks. In addition, DCL consistently had faster runtimes than the other algorithms. In the application to the real datasets, DCL identified rs6784615, located on the NISCH gene, and rs10824310, located on the PRKG1 gene, as direct causes of late onset Alzheimer's disease (LOAD) development. In addition, DCL identified ER category as a direct predictor of breast cancer mortality within 5 years, and HER2 status as a direct predictor of 10-year breast cancer mortality. These predictors have been identified in previous studies to have a direct causal relationship with their respective phenotypes, supporting the predictive power of DCL. When the other algorithms discovered predictors from the real datasets, these predictors were either also found by DCL or could not be supported by previous studies. Our results show that DCL outperforms FGS, PC, CPC, and FCI in almost every case, demonstrating its potential to advance causal learning. Furthermore, our DCL algorithm effectively identifies direct causes in the LOAD and Metabric GWAS datasets, which indicates its potential for clinical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

PI3-kinase promotes TRPV2 activity independently of channel translocation to the plasma membrane.

PubMed

Penna, Aubin; Juvin, Véronique; Chemin, Jean; Compan, Vincent; Monet, Michael; Rassendren, François-A

2006-06-01

Cellular or chemical activators for most transient receptor potential channels of the vanilloid subfamily (TRPV) have been identified in recent years. A remarkable exception to this is TRPV2, for which cellular events leading to channel activation are still a matter of debate. Diverse stimuli such as extreme heat or phosphatidylinositol-3 kinase (PI3-kinase) regulated membrane insertion have been shown to promote TRPV2 channel activity. However, some of these results have proved difficult to reproduce and may underlie different gating mechanisms depending on the cell type in which TRPV2 channels are expressed. Here, we show that expression of recombinant TRPV2 can induce cytotoxicity that is directly related to channel activity since it can be prevented by introducing a charge substitution in the pore-forming domain of the channel, or by reducing extracellular calcium. In stably transfected cells, TRPV2 expression results in an outwardly rectifying current that can be recorded at all potentials, and in an increase of resting intracellular calcium concentration that can be partly prevented by serum starvation. Using cytotoxicity as a read-out of channel activity and direct measurements of cell surface expression of TRPV2, we show that inhibition of the PI3-kinase decreases TRPV2 channel activity but does not affect the trafficking of the channel to the plasma membrane. It is concluded that PI3-kinase induces or modulates the activity of recombinant TRPV2 channels; in contrast to the previously proposed mechanism, activation of TRPV2 channels by PI3-kinase is not due to channel translocation to the plasma membrane.

SU-F-207-16: CT Protocols Optimization Using Model Observer

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

Tseng, H; Fan, J; Kupinski, M

2015-06-15

Purpose: To quantitatively evaluate the performance of different CT protocols using task-based measures of image quality. This work studies the task of size and the contrast estimation of different iodine concentration rods inserted in head- and body-sized phantoms using different imaging protocols. These protocols are designed to have the same dose level (CTDIvol) but using different X-ray tube voltage settings (kVp). Methods: Different concentrations of iodine objects inserted in a head size phantom and a body size phantom are imaged on a 64-slice commercial CT scanner. Scanning protocols with various tube voltages (80, 100, and 120 kVp) and current settingsmore » are selected, which output the same absorbed dose level (CTDIvol). Because the phantom design (size of the iodine objects, the air gap between the inserted objects and the phantom) is not ideal for a model observer study, the acquired CT images are used to generate simulation images with four different sizes and five different contracts iodine objects. For each type of the objects, 500 images (100 x 100 pixels) are generated for the observer study. The observer selected in this study is the channelized scanning linear observer which could be applied to estimate the size and the contrast. The figure of merit used is the correct estimation ratio. The mean and the variance are estimated by the shuffle method. Results: The results indicate that the protocols with 100 kVp tube voltage setting provides the best performance for iodine insert size and contrast estimation for both head and body phantom cases. Conclusion: This work presents a practical and robust quantitative approach using channelized scanning linear observer to study contrast and size estimation performance from different CT protocols. Different protocols at same CTDIvol setting could Result in different image quality performance. The relationship between the absorbed dose and the diagnostic image quality is not linear.« less

Mapping of voltage sensor positions in resting and inactivated mammalian sodium channels by LRET

PubMed Central

Kubota, Tomoya; Durek, Thomas; Dang, Bobo; Finol-Urdaneta, Rocio K.; Craik, David J.; Kent, Stephen B. H.; French, Robert J.; Bezanilla, Francisco; Correa, Ana M.

2017-01-01

Voltage-gated sodium channels (Navs) play crucial roles in excitable cells. Although vertebrate Nav function has been extensively studied, the detailed structural basis for voltage-dependent gating mechanisms remain obscure. We have assessed the structural changes of the Nav voltage sensor domain using lanthanide-based resonance energy transfer (LRET) between the rat skeletal muscle voltage-gated sodium channel (Nav1.4) and fluorescently labeled Nav1.4-targeting toxins. We generated donor constructs with genetically encoded lanthanide-binding tags (LBTs) inserted at the extracellular end of the S4 segment of each domain (with a single LBT per construct). Three different Bodipy-labeled, Nav1.4-targeting toxins were synthesized as acceptors: β-scorpion toxin (Ts1)-Bodipy, KIIIA-Bodipy, and GIIIA-Bodipy analogs. Functional Nav-LBT channels expressed in Xenopus oocytes were voltage-clamped, and distinct LRET signals were obtained in the resting and slow inactivated states. Intramolecular distances computed from the LRET signals define a geometrical map of Nav1.4 with the bound toxins, and reveal voltage-dependent structural changes related to channel gating. PMID:28202723

Mapping of voltage sensor positions in resting and inactivated mammalian sodium channels by LRET.

PubMed

Kubota, Tomoya; Durek, Thomas; Dang, Bobo; Finol-Urdaneta, Rocio K; Craik, David J; Kent, Stephen B H; French, Robert J; Bezanilla, Francisco; Correa, Ana M

2017-03-07

Voltage-gated sodium channels (Navs) play crucial roles in excitable cells. Although vertebrate Nav function has been extensively studied, the detailed structural basis for voltage-dependent gating mechanisms remain obscure. We have assessed the structural changes of the Nav voltage sensor domain using lanthanide-based resonance energy transfer (LRET) between the rat skeletal muscle voltage-gated sodium channel (Nav1.4) and fluorescently labeled Nav1.4-targeting toxins. We generated donor constructs with genetically encoded lanthanide-binding tags (LBTs) inserted at the extracellular end of the S4 segment of each domain (with a single LBT per construct). Three different Bodipy-labeled, Nav1.4-targeting toxins were synthesized as acceptors: β-scorpion toxin (Ts1)-Bodipy, KIIIA-Bodipy, and GIIIA-Bodipy analogs. Functional Nav-LBT channels expressed in Xenopus oocytes were voltage-clamped, and distinct LRET signals were obtained in the resting and slow inactivated states. Intramolecular distances computed from the LRET signals define a geometrical map of Nav1.4 with the bound toxins, and reveal voltage-dependent structural changes related to channel gating.

Handheld Universal Diagnostic Sensor

NASA Technical Reports Server (NTRS)

Chan, Eugene

2012-01-01

The rHEALTH technology is designed to shrink an entire hospital testing laboratory onto a handheld device. A physician or healthcare provider performs the test by collecting a fingerstick of blood from a patient. The tiny volume of blood is inserted into the rHEALTH device. Inside the device is a microfluidic chip that contains small channels about the width of a human hair. These channels help move the blood and analyze the blood sample. The rHEALTH sensor uses proprietary reagents called nanostrips, which are nanoscale test strips that enable the clinical assays. The readout is performed by laser-induced fluorescence. Overall, the time from blood collection through analysis is less than a minute.

HIGH TEMPERATURE, HIGH POWER HETEROGENEOUS NUCLEAR REACTOR

DOEpatents

Hammond, R.P.; Wykoff, W.R.; Busey, H.M.

1960-06-14

A heterogeneous nuclear reactor is designed comprising a stationary housing and a rotatable annular core being supported for rotation about a vertical axis in the housing, the core containing a plurality of radial fuel- element supporting channels, the cylindrical empty space along the axis of the core providing a central plenum for the disposal of spent fuel elements, the core cross section outer periphery being vertically gradated in radius one end from the other to provide a coolant duct between the core and the housing, and means for inserting fresh fuel elements in the supporting channels under pressure and while the reactor is in operation.

Performance interface document for the S-band diplexer for space users of NASA networks

NASA Technical Reports Server (NTRS)

Line, L. G.

1985-01-01

This report discusses the test results and interfacing information of the S-band diplexer development program supported by RTOP 310 funding. The program was implemented to reduce the S-band transponder noise figure by minimizing the receive channel insertion loss and to also provide Space Transportation System (STS) compatibility by providing 70-db rejection up to 16 GHz in the receive channel. This compatibility includes rejection of signals from the Shuttle S-band Data Link, the K-band Data Link, and the K-band Rendezvous Radar. The first of many projects to benefit from this accomplishment was the Earth Radiation Budget Satellite (ERBS).

Heat Transport Enhancement of Turbulent Thermal Convection by Inserted Channels

NASA Astrophysics Data System (ADS)

Xia, Ke-Qing; Zhang, Lu

2017-11-01

We report an experimental study on the heat transport properties of turbulent Rayleigh Benard Convection (RBC) in a rectangular cell with two types of 3D-printed structures inserted inside. The first one splits the original rectangular cell into 60 identical sub cells whose aspect ratio is 1:1:10 (length, width, height). The second one splits the cell into 30 sub cells, each with a 1:2:10 aspect ratio and a baffle in the center. We find that for large Rayleigh numbers (Ra), the Nusselt numbers (Nu) of both structures increase compared with that of the empty rectangular cell. An enhancement in Nu as much as 20% is found for the second type of insertion at Rayleigh number 2 ×109 . Moreover, the Nu-Ra scaling shows a transition with both geometries. The particle image velocimetry (PIV) measurement within a single sub unit indicates that the transition may be related to the laminar to turbulent transition in flow field. Direct numerical simulations (DNS) confirm the experimental results. Our results demonstrate the potential in using insertions to enhance passive heat transfer. This work was supported by the Research Grants Council (RGC) of HKSAR (Nos. CUHK404513 and CUHK14301115).

Non-common path aberration correction in an adaptive optics scanning ophthalmoscope.

PubMed

Sulai, Yusufu N; Dubra, Alfredo

2014-09-01

The correction of non-common path aberrations (NCPAs) between the imaging and wavefront sensing channel in a confocal scanning adaptive optics ophthalmoscope is demonstrated. NCPA correction is achieved by maximizing an image sharpness metric while the confocal detection aperture is temporarily removed, effectively minimizing the monochromatic aberrations in the illumination path of the imaging channel. Comparison of NCPA estimated using zonal and modal orthogonal wavefront corrector bases provided wavefronts that differ by ~λ/20 in root-mean-squared (~λ/30 standard deviation). Sequential insertion of a cylindrical lens in the illumination and light collection paths of the imaging channel was used to compare image resolution after changing the wavefront correction to maximize image sharpness and intensity metrics. Finally, the NCPA correction was incorporated into the closed-loop adaptive optics control by biasing the wavefront sensor signals without reducing its bandwidth.

Molecular transport through large-diameter DNA nanopores

NASA Astrophysics Data System (ADS)

Krishnan, Swati; Ziegler, Daniela; Arnaut, Vera; Martin, Thomas G.; Kapsner, Korbinian; Henneberg, Katharina; Bausch, Andreas R.; Dietz, Hendrik; Simmel, Friedrich C.

2016-09-01

DNA-based nanopores are synthetic biomolecular membrane pores, whose geometry and chemical functionality can be tuned using the tools of DNA nanotechnology, making them promising molecular devices for applications in single-molecule biosensing and synthetic biology. Here we introduce a large DNA membrane channel with an ~4 nm diameter pore, which has stable electrical properties and spontaneously inserts into flat lipid bilayer membranes. Membrane incorporation is facilitated by a large number of hydrophobic functionalizations or, alternatively, streptavidin linkages between biotinylated channels and lipids. The channel displays an Ohmic conductance of ~3 nS, consistent with its size, and allows electrically driven translocation of single-stranded and double-stranded DNA analytes. Using confocal microscopy and a dye influx assay, we demonstrate the spontaneous formation of membrane pores in giant unilamellar vesicles. Pores can be created both in an outside-in and an inside-out configuration.

Modular, security enclosure and method of assembly

DOEpatents

Linker, Kevin L.; Moyer, John W.

1995-01-01

A transportable, reusable rapidly assembled and disassembled, resizable modular, security enclosure utilizes a stepped panel construction. Each panel has an inner portion and an outer portion which form joints. A plurality of channels can be affixed to selected joints of the panels. Panels can be affixed to a base member and then affixed to one another by the use of elongated pins extending through the channel joints. Alternatively, the base member can be omitted and the panels themselves can be used as the floor of the enclosure. The pins will extend generally parallel to the joint in which they are located. These elongated pins are readily inserted into and removable from the channels in a predetermined sequence to allow assembly and disassembly of the enclosure. A door constructed from panels is used to close the opening to the enclosure.

Experimental study of multichromatic terahertz wave propagation through planar micro-channels

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

Shin, Young-Min -Min; Northern Illinois Univ., Dekalb, IL; Fermi National Accelerator Lab.

2012-04-10

Previous theoretical and numerical studies [Y. M. Shin and L. R. Barnett, Appl. Phys. Lett. 92, 091501 (2008) and Y. M. Shin et al., Appl. Phys. Lett. 93, 221504 (2008)] have reported that a planar micro-channel with an asymmetric corrugation array supports strongly confined propagation of broadband THz plasmonic waves. The highly broad spectral response is experimentally demonstrated in the near-THz regime of 0.19-0.265 THz. Signal reflection and transmission tests on the three designed micro-channels including directional couplers resulted in a full-width-half-maximum bandwidth of ~ 50-60GHz with an insertion loss of approximately -5 dB, which is in good agreement withmore » simulation data. As a result, these micro-structures can be utilized for free electron beam and electronic/optic integrated devices« less

Structure and dynamics of cationic membrane peptides and proteins: Insights from solid-state NMR

PubMed Central

Hong, Mei; Su, Yongchao

2011-01-01

Many membrane peptides and protein domains contain functionally important cationic Arg and Lys residues, whose insertion into the hydrophobic interior of the lipid bilayer encounters significant energy barriers. To understand how these cationic molecules overcome the free energy barrier to insert into the lipid membrane, we have used solid-state NMR spectroscopy to determine the membrane-bound topology of these peptides. A versatile array of solid-state NMR experiments now readily yields the conformation, dynamics, orientation, depth of insertion, and site-specific protein–lipid interactions of these molecules. We summarize key findings of several Arg-rich membrane peptides, including β-sheet antimicrobial peptides, unstructured cell-penetrating peptides, and the voltage-sensing helix of voltage-gated potassium channels. Our results indicate the central role of guanidinium-phosphate and guanidinium-water interactions in dictating the structural topology of these cationic molecules in the lipid membrane, which in turn account for the mechanisms of this functionally diverse class of membrane peptides. PMID:21344534

[Cochlear implantation in patients with Waardenburg syndrome type II].

PubMed

Wan, Liangcai; Guo, Menghe; Chen, Shuaijun; Liu, Shuangriu; Chen, Hao; Gong, Jian

2010-05-01

To describe the multi-channel cochlear implantation in patients with Waardenburg syndrome including surgeries, pre and postoperative hearing assessments as well as outcomes of speech recognition. Multi-channel cochlear implantation surgeries have been performed in 12 cases with Waardenburg syndrome type II in our department from 2000 to 2008. All the patients received multi-channel cochlear implantation through transmastoid facial recess approach. The postoperative outcomes of 12 cases were compared with 12 cases with no inner ear malformation as a control group. The electrodes were totally inserted into the cochlear successfully, there was no facial paralysis and cerebrospinal fluid leakage occurred after operation. The hearing threshold in this series were similar to that of the normal cochlear implantation. After more than half a year of speech rehabilitation, the abilities of speech discrimination and spoken language of all the patients were improved compared with that of preoperation. Multi-channel cochlear implantation could be performed in the cases with Waardenburg syndrome, preoperative hearing and images assessments should be done.

Design, synthesis, and biological evaluation of stable β6.3-Helices: Discovery of non-hemolytic antibacterial peptides.

PubMed

Reddy, Damodara N; Singh, Sukrit; Ho, Chris M W; Patel, Janki; Schlesinger, Paul; Rodgers, Stephen; Doctor, Allan; Marshall, Garland R

2018-04-10

Gramicidin A, a topical antibiotic made from alternating L and D amino acids, is characterized by its wide central pore; upon insertion into membranes, it forms channels that disrupts ion gradients. We present helical peptidomimetics with this characteristic wide central pore that have been designed to mimic gramicidin A channels. Mimetics were designed using molecular modeling focused on oligomers of heterochiral dipeptides of proline analogs, in particular azaproline (AzPro). Molecular Dynamics simulations in water confirmed the stability of the designed helices. A sixteen-residue Formyl-(AzPro-Pro) 8 -NHCH 2 CH 2 OH helix was synthesized as well as a full thirty-two residue Cbz-(AzPro-Pro) 16 -O t Bu channels. No liposomal lysis activity was observed suggesting lack of channel formation, possibly due to inappropriate hydrogen-bonding interactions in the membrane. These peptidomimetics also did not hemolyze red blood cells, unlike gramicidin A. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

The Mosquito and the Colossus: Operation Just Cause through the Eyes of General Manuel Antonio Noriega

DTIC Science & Technology

2008-05-22

power via a coup. 2. Historical role is the modernization of society. 3. The bourgeoisie trades its political rights and power in exchange for the...years at Miami’s Federal Correctional Institution (FCI).60 General Noriega is now to be sent to France where he was convicted for money laundering...2165809,00.html (accessed December 22, 2007). 61 Cristina Machin, interview by author, Leavenworth, KS., October 7, 2007. In 1987 France gave General

Communication Interface for a System of Distributed Processes.

DTIC Science & Technology

1981-03-03

Tnterprocess Communication Service Apnlied in a nistrihuted Data Rase System" (submitte to VCI, Miinchen 10/Rl) and "The Trans- port Service of an...1980 4) B6’-hme, K.: An Tnternrocess Communication Service Applied in a Distribut.1 Data Pase System. Submitted to FCI, tliinchen, Oct. 3091l 5) ribme...K(. The "ransport Service of an Tnterprocess Commiunication Systell. Snbmitte to 7th Data Cor’nunicatinrin rooi1 !’exico City, Oct. 1091 ’"’h~e oi1

Efficacy of a Novel Narrow Knife with Water Jet Function for Colorectal Endoscopic Submucosal Dissection.

PubMed

Yoshida, Naohisa; Toyonaga, Takashi; Murakami, Takaaki; Hirose, Ryohei; Ogiso, Kiyoshi; Inada, Yutaka; Rani, Rafiz Abdul; Naito, Yuji; Kishimoto, Mitsuo; Ohara, Yoshiko; Azuma, Takeshi; Itoh, Yoshito

2017-01-01

With respect to the knife's design in colorectal endoscopic submucosal dissection (ESD), diameter, water jet function, and electric power are important because these relate to efficient dissection. In this study, we analyzed a novel, narrow ball tip-typed ESD knife with water jet function (Flush knife BT-S, diameter: 2.2 mm, length: 2000 mm, Fujifilm Co., Tokyo, Japan) compared to a regular diameter knife (Flush knife BT, diameter: 2.6 mm, length: 1800 mm). In laboratory and clinical research, electric power, knife insertion time, vacuum/suction amount with knife in the endoscopic channel, and water jet function were analyzed. We used a knife 2.0 mm long for BT-S and BT knives. The BT-S showed faster mean knife insertion time (sec) and better vacuum amount (ml/min) compared to the BT (insertion time: 16.7 versus 21.6, p < 0.001, vacuum amount: 38.0 versus 14.0, p < 0.01). Additionally, the water jet function of the BT-S was not inferior. In 39 colorectal ESD cases in two institutions, there were mean 4.7 times (range: 1-28) of knife insertion. Suction under knife happened 59% (23/39) and suction of fluid could be done in 100%. Our study showed that the narrow knife allows significantly faster knife insertion, better vacuum function, and effective clinical results.

The Droplets Condensate Centering in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

NASA Astrophysics Data System (ADS)

Seryakov, A. V.; Shakshin, S. L.; Alekseev, A. P.

2017-11-01

The results of experimental studies of the process of condensate microdroplets centering contained in the moving moist vapour in the vapour channel of short heat pipes (HPs) for large thermal loads are presented. A vapour channel formed by capillary-porous insert in the form of the inner Laval-liked nozzle along the entire length of the HP. In the upper cover forming a condensation surface in the HP, on the diametrical line are installed capacitive sensors, forming three capacitors located at different distances from the longitudinal axis of the vapour channel. With increasing heat load and the boil beginning in the evaporator a large amount of moist vapour in the vapour channel of HP occur the pressure pulsation with frequency of 400-500 Hz and amplitude up to 1·104Pa. These pulsations affect the moving of the inertial droplets subsystem of the vapour and due to the heterogeneity of the velocity profile around the particle flow in the vapour channel at the diameter of microdroplets occurs transverse force, called the Saffman force and shear microdroplets to the center of vapour channel. Using installed in the top cover capacitors we can record the radial displacement of the condensable microdroplets.

Mixed convection peristaltic motion of copper-water nanomaterial with velocity slip effects in a curved channel.

PubMed

Hayat, T; Farooq, S; Alsaedi, A

2017-04-01

The primary objective of present analysis is to model the peristalsis of copper-water based nanoliquid in the presence of first order velocity and thermal slip conditions in a curved channel. Mixed convection, viscous dissipation and heat generation/absorption are also accounted. Mathematical formulation is simplified under the assumption of small Reynolds number and large wavelength. Regular perturbation technique is employed to find the solution of the resulting equations in terms of series for small Brinkman number. The final expression for pressure gradient, pressure rise, stream function, velocity and temperature are obtained and discussed through graphs. Mathematica software is utilized to compute the solution of the system of equations and to plot the graphical results. Results indicates that insertion of 30% copper nanoparticles in the basefluid (water) velocity and temperature reduces by almost 3% and 40% respecively. Moreover it is seen that size of the trapped bolus also reduces almost 20% with the insertion of 20% nanoparticles (copper) in the basefluid (water). It is noted that velocity and temperature are decreasing functions of nanoparticle volume fraction. Moreover the temperature rises when heat generation parameter and Brinkman number are enhanced. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrotonic potentials in Aloe vera L.: Effects of intercellular and external electrodes arrangement.

PubMed

Volkov, Alexander G; Nyasani, Eunice K; Tuckett, Clayton; Scott, Jessenia M; Jackson, Mariah M Z; Greeman, Esther A; Greenidge, Ariane S; Cohen, Devin O; Volkova, Maia I; Shtessel, Yuri B

2017-02-01

Electrostimulation of plants can induce plant movements, activation of ion channels, ion transport, gene expression, enzymatic systems activation, electrical signaling, plant-cell damage, enhanced wound healing, and influence plant growth. Here we found that electrical networks in plant tissues have electrical differentiators. The amplitude of electrical responses decreases along a leaf and increases by decreasing the distance between polarizing Pt-electrodes. Intercellular Ag/AgCl electrodes inserted in a leaf and extracellular Ag/AgCl electrodes attached to the leaf surface were used to detect the electrotonic potential propagation along a leaf of Aloe vera. There is a difference in duration and amplitude of electrical potentials measured by electrodes inserted in a leaf and those attached to a leaf's surface. If the external reference electrode is located in the soil near the root, it changes the amplitude and duration of electrotonic potentials due to existence of additional resistance, capacitance, ion channels and ion pumps in the root. The information gained from this study can be used to elucidate extracellular and intercellular communication in the form of electrical signals within plants. Copyright © 2016 Elsevier B.V. All rights reserved.

Alternative Splicing Generates a Novel Truncated Cav1.2 Channel in Neonatal Rat Heart*

PubMed Central

Liao, Ping; Yu, Dejie; Hu, Zhenyu; Liang, Mui Cheng; Wang, Jue Jin; Yu, Chye Yun; Ng, Gandi; Yong, Tan Fong; Soon, Jia Lin; Chua, Yeow Leng; Soong, Tuck Wah

2015-01-01

L-type Cav1.2 Ca2+ channel undergoes extensive alternative splicing, generating functionally different channels. Alternatively spliced Cav1.2 Ca2+ channels have been found to be expressed in a tissue-specific manner or under pathological conditions. To provide a more comprehensive understanding of alternative splicing in Cav1.2 channel, we systematically investigated the splicing patterns in the neonatal and adult rat hearts. The neonatal heart expresses a novel 104-bp exon 33L at the IVS3-4 linker that is generated by the use of an alternative acceptor site. Inclusion of exon 33L causes frameshift and C-terminal truncation. Whole-cell electrophysiological recordings of Cav1.233L channels expressed in HEK 293 cells did not detect any current. However, when co-expressed with wild type Cav1.2 channels, Cav1.233L channels reduced the current density and altered the electrophysiological properties of the wild type Cav1.2 channels. Interestingly, the truncated 3.5-domain Cav1.233L channels also yielded a dominant negative effect on Cav1.3 channels, but not on Cav3.2 channels, suggesting that Cavβ subunits is required for Cav1.233L regulation. A biochemical study provided evidence that Cav1.233L channels enhanced protein degradation of wild type channels via the ubiquitin-proteasome system. Although the physiological significance of the Cav1.233L channels in neonatal heart is still unknown, our report demonstrates the ability of this novel truncated channel to modulate the activity of the functional Cav1.2 channels. Moreover, the human Cav1.2 channel also contains exon 33L that is developmentally regulated in heart. Unexpectedly, human exon 33L has a one-nucleotide insertion that allowed in-frame translation of a full Cav1.2 channel. An electrophysiological study showed that human Cav1.233L channel is a functional channel but conducts Ca2+ ions at a much lower level. PMID:25694430

A COMPARISON OF EXPERIMENTS AND THREE-DIMENSIONAL ANALYSIS TECHNIQUES. PART I. UNPOISONED UNIFORM SLAB CORE WITH A PARTIALLY INSERTED HAFNIUM ROD

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

Renzi, N.E.; Roseberry, R.J.

>The experimental measurements and nuclear analysis of a uniformly loaded, unpoisoned slab core with a partially insented hafnium rod are described. Comparisons of experimental data with calculated results of the UFO code and flux synthesis techniques are given. It was concluded that one of the flux synthesis techniques and the UFO code are able to predict flux distributions to within approximately 5% of experiment for most cases. An error of approximately 10% was found in the synthesis technique for a channel near the partially inserted rod. The various calculations were able to predict neutron pulsed shutdowns to only approximately 30%.more » (auth)« less

Evaluation of a novel, ultrathin, tip-bending endoscope in a synthetic force-sensing pancreas with comparison to medical guide wires

PubMed Central

Chandler, John E; Lee, Cameron M; Babchanik, Alexander P; Melville, C David; Saunders, Michael D; Seibel, Eric J

2012-01-01

Purpose Direct visualization of pancreatic ductal tissue is critical for early diagnosis of pancreatic diseases and for guiding therapeutic interventions. A novel, ultrathin (5 Fr) scanning fiber endoscope (SFE) with tip-bending capability has been developed specifically to achieve high resolution imaging as a pancreatoscope during endoscopic retrograde cholangiopancreatography (ERCP). This device has potential to dramatically improve both diagnostic and therapeutic capabilities during ERCP by providing direct video feedback and tool guidance to clinicians. Methods Invasiveness of the new tip-bending SFE was evaluated by a performance comparison to ERCP guide wires, which are routinely inserted into the pancreatic duct during ERCP. An in vitro test model with four force sensors embedded in a synthetic pancreas was designed to detect and compare the insertion forces for 0.89 mm and 0.53 mm diameter guide wires as well as the 1.7 mm diameter SFE. Insertions were performed through the working channel of a therapeutic duodenoscope for the two types of guide wires and using a statistically similar direct insertion method for comparison to the SFE. Results Analysis of the forces detected by the sensors showed the smaller diameter 0.53 mm wire produced significantly less average and maximum forces during insertion than the larger diameter 0.89 mm wire. With the use of tip-bending and optical visualization, the 1.7 mm diameter SFE produced significantly less average force during insertion than the 0.89 mm wire at every sensor, despite its larger size. It was further shown that the use of tip-bending with the SFE significantly reduced the forces at all sensors, compared to insertions when tip-bending was not used. Conclusion Combining high quality video imaging with two-axis tip-bending allows a larger diameter guide wire-style device to be inserted into the pancreatic duct during ERCP with improved capacity to perform diagnostics and therapy. PMID:23166452

Examining evolving performance on the Force Concept Inventory using factor analysis

NASA Astrophysics Data System (ADS)

Semak, M. R.; Dietz, R. D.; Pearson, R. H.; Willis, C. W.

2017-06-01

The application of factor analysis to the Force Concept Inventory (FCI) has proven to be problematic. Some studies have suggested that factor analysis of test results serves as a helpful tool in assessing the recognition of Newtonian concepts by students. Other work has produced at best ambiguous results. For the FCI administered as a pre- and post-test, we see factor analysis as a tool by which the changes in conceptual associations made by our students may be gauged given the evolution of their response patterns. This analysis allows us to identify and track conceptual linkages, affording us insight as to how our students have matured due to instruction. We report on our analysis of 427 pre- and post-tests. The factor models for the pre- and post-tests are explored and compared along with the methodology by which these models were fit to the data. The post-test factor pattern is more aligned with an expert's interpretation of the questions' content, as it allows for a more readily identifiable relationship between factors and physical concepts. We discuss this evolution in the context of approaching the characteristics of an expert with force concepts. Also, we find that certain test items do not significantly contribute to the pre- or post-test factor models and attempt explanations as to why this is so. This may suggest that such questions may not be effective in probing the conceptual understanding of our students.

Pair 2-electron reduced density matrix theory using localized orbitals

NASA Astrophysics Data System (ADS)

Head-Marsden, Kade; Mazziotti, David A.

2017-08-01

Full configuration interaction (FCI) restricted to a pairing space yields size-extensive correlation energies but its cost scales exponentially with molecular size. Restricting the variational two-electron reduced-density-matrix (2-RDM) method to represent the same pairing space yields an accurate lower bound to the pair FCI energy at a mean-field-like computational scaling of O (r3) where r is the number of orbitals. In this paper, we show that localized molecular orbitals can be employed to generate an efficient, approximately size-extensive pair 2-RDM method. The use of localized orbitals eliminates the substantial cost of optimizing iteratively the orbitals defining the pairing space without compromising accuracy. In contrast to the localized orbitals, the use of canonical Hartree-Fock molecular orbitals is shown to be both inaccurate and non-size-extensive. The pair 2-RDM has the flexibility to describe the spectra of one-electron RDM occupation numbers from all quantum states that are invariant to time-reversal symmetry. Applications are made to hydrogen chains and their dissociation, n-acene from naphthalene through octacene, and cadmium telluride 2-, 3-, and 4-unit polymers. For the hydrogen chains, the pair 2-RDM method recovers the majority of the energy obtained from similar calculations that iteratively optimize the orbitals. The localized-orbital pair 2-RDM method with its mean-field-like computational scaling and its ability to describe multi-reference correlation has important applications to a range of strongly correlated phenomena in chemistry and physics.

Bioliteracy and Teaching Efficacy: What Biologists Can Learn from Physicists

PubMed Central

Klymkowsky, Michael W.; Garvin-Doxas, Kathy; Zeilik, Michael

2003-01-01

The introduction of the Force Concept Inventory (FCI) by David Hestenes and colleagues in 1992 produced a remarkable impact within the community of physics teachers. An instrument to measure student comprehension of the Newtonian concept of force, the FCI demonstrates that active learning leads to far superior student conceptual learning than didactic lectures. Compared to a working knowledge of physics, biological literacy and illiteracy have an even more direct, dramatic, and personal impact. They shape public research and reproductive health policies, the acceptance or rejection of technological advances, such as vaccinations, genetically modified foods and gene therapies, and, on the personal front, the reasoned evaluation of product claims and lifestyle choices. While many students take biology courses at both the secondary and the college levels, there is little in the way of reliable and valid assessment of the effectiveness of biological education. This lack has important consequences in terms of general bioliteracy and, in turn, for our society. Here we describe the beginning of a community effort to define what a bioliterate person needs to know and to develop, validate, and disseminate a tiered series of instruments collectively known as the Biology Concept Inventory (BCI), which accurately measures student comprehension of concepts in introductory, genetic, molecular, cell, and developmental biology. The BCI should serve as a lever for moving our current educational system in a direction that delivers a deeper conceptual understanding of the fundamental ideas upon which biology and biomedical sciences are based. PMID:14506504

High Power HF Excitation of Low Frequency Stimulated Electrostatic Waves in the Ionospheric Plasma over HAARP

NASA Astrophysics Data System (ADS)

Bernhardt, Paul; Selcher, Craig A.

High Power electromagnetic (EM) waves transmitted from the HAARP facility in Alaska can excite low frequency electrostatic waves by several processes including (1) direct magnetized stimulated Brillouin scatter (MSBS) and (2) parametric decay of high frequency electrostatic waves into electron and ion Bernstein waves. Either an ion acoustic (IA) wave with a frequency less than the ion cyclotron frequency (fCI) or an electrostatic ion cyclotron (EIC) wave just above fCI can be produced by MSBS. The coupled equations describing the MSBS instabil-ity show that the production of both IA and EIC waves is strongly influenced by the wave propagation direction relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions (SEE) using the HAARP transmitter in Alaska have confirmed the theoretical predictions that only IA waves are excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The electron temperature in the heated plasma is obtained from the IA spectrum offsets from the pump frequency. The ion composition can be determined from the measured EIC frequency. Near the second harmonic of the electron cyclotron frequency, the EM pump wave is converted into an electron Bernstein (EB) wave that decays into another EB wave and an ion Bernstein (IB) wave. Strong cyclotron resonance with the EB wave leads to acceleration of the electrons. Ground based SEE observations are related to the theory of low-frequency electrostatic wave generation.

Effect of Lorcaserin Alone and in Combination with Phentermine on Food Cravings After 12-Week Treatment: A Randomized Substudy.

PubMed

Rebello, Candida J; Nikonova, Elena V; Zhou, Sharon; Aronne, Louis J; Fujioka, Ken; Garvey, W Timothy; Smith, Steven R; Coulter, Ann A; Greenway, Frank L

2018-02-01

This study evaluated the effect of lorcaserin 10 mg twice daily (LOR BID), or with phentermine 15 mg once daily (LOR BID + PHEN QD) and 15 mg twice daily (LOR BID + PHEN BID), in conjunction with energy restriction on food cravings. Two hundred and thirty-five patients without diabetes but with obesity or overweight and ≥ 1 comorbidity received LOR BID, LOR BID + PHEN QD, or LOR BID + PHEN BID for 12 weeks in a randomized double-blind study. The Food Craving Inventory (FCI) and the Control of Eating Questionnaire (COEQ) were administered over 12 weeks. The FCI total score and the subscale scores reduced from baseline in all groups. The least squares means (95% confidence intervals) for the total scores were -0.65 (-0.75 to -0.55), -0.75 (-0.84 to -0.65), and -0.84 (-0.95 to -0.74) in the LOR BID, LOR BID + PHEN QD, and LOR BID + PHEN BID groups, respectively. Cravings assessed by COEQ reduced from baseline in all groups. In general, the combination treatments were more effective than lorcaserin alone. At week 12, except for fruit juice and dairy products, general and specific cravings reduced in LOR BID + PHEN BID compared with LOR BID (P < 0.05). Lorcaserin in combination with phentermine improves control of food cravings during short-term energy restriction. © 2018 The Obesity Society.

Non-common path aberration correction in an adaptive optics scanning ophthalmoscope

PubMed Central

Sulai, Yusufu N.; Dubra, Alfredo

2014-01-01

The correction of non-common path aberrations (NCPAs) between the imaging and wavefront sensing channel in a confocal scanning adaptive optics ophthalmoscope is demonstrated. NCPA correction is achieved by maximizing an image sharpness metric while the confocal detection aperture is temporarily removed, effectively minimizing the monochromatic aberrations in the illumination path of the imaging channel. Comparison of NCPA estimated using zonal and modal orthogonal wavefront corrector bases provided wavefronts that differ by ~λ/20 in root-mean-squared (~λ/30 standard deviation). Sequential insertion of a cylindrical lens in the illumination and light collection paths of the imaging channel was used to compare image resolution after changing the wavefront correction to maximize image sharpness and intensity metrics. Finally, the NCPA correction was incorporated into the closed-loop adaptive optics control by biasing the wavefront sensor signals without reducing its bandwidth. PMID:25401020

Boost Up Carrier Mobility for Ferroelectric Organic Transistor Memory via Buffering Interfacial Polarization Fluctuation

PubMed Central

Sun, Huabin; Wang, Qijing; Li, Yun; Lin, Yen-Fu; Wang, Yu; Yin, Yao; Xu, Yong; Liu, Chuan; Tsukagoshi, Kazuhito; Pan, Lijia; Wang, Xizhang; Hu, Zheng; Shi, Yi

2014-01-01

Ferroelectric organic field-effect transistors (Fe-OFETs) have been attractive for a variety of non-volatile memory device applications. One of the critical issues of Fe-OFETs is the improvement of carrier mobility in semiconducting channels. In this article, we propose a novel interfacial buffering method that inserts an ultrathin poly(methyl methacrylate) (PMMA) between ferroelectric polymer and organic semiconductor layers. A high field-effect mobility (μFET) up to 4.6 cm2 V−1 s−1 is obtained. Subsequently, the programming process in our Fe-OFETs is mainly dominated by the switching between two ferroelectric polarizations rather than by the mobility-determined charge accumulation at the channel. Thus, the “reading” and “programming” speeds are significantly improved. Investigations show that the polarization fluctuation at semiconductor/insulator interfaces, which affect the charge transport in conducting channels, can be suppressed effectively using our method. PMID:25428665

Beam Test of a Dielectric Loaded High Pressure RF Cavity for Use in Muon Cooling Channels

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

Freemire, Ben; Bowring, Daniel; Kochemirovskiy, Alexey

2016-06-01

Bright muon sources require six dimensional cooling to achieve acceptable luminosities. Ionization cooling is the only known method able to do so within the muon lifetime. One proposed cooling channel, the Helical Cooling Channel, utilizes gas filled radio frequency cavities to both mitigate RF breakdown in the presence of strong, external magnetic fields, and provide the cooling medium. Engineering constraints on the diameter of the magnets within which these cavities operate dictate the radius of the cavities be decreased at their nominal operating frequency. To accomplish this, one may load the cavities with a larger dielectric material. A 99.5% aluminamore » ring was inserted in a high pressure RF test cell and subjected to an intense proton beam at the MuCool Test Area at Fermilab. The results of the performance of this dielectric loaded high pressure RF cavity will be presented.« less

Visible CWDM system design for Multi-Gbit/s transmission over SI-POF

NASA Astrophysics Data System (ADS)

Vázquez, Carmen; Pinzón, Plinio Jesús; Pérez, Isabel

2015-01-01

In order to increase the data rates of Multi-Gbit/s links based on large core step index (SI) plastic optical fibers (POF), different modulation scenes have been proposed. Another option is to use multiple optical carriers for parallel transmission of communication channels over the same fiber. Some designs to reach data rates of 14.77 Gb/s in 50 m, with 4 channels have been developed by off line processing. In this work, designs to test the potential of real Multi- Gbit/s transmission systems using commercial products are reported. Special care in designing low insertion loss multiplexers and demultiplexers is carried out to allow for greener solutions in terms of power consumption.

Interaction of elaiophylin with model bilayer membrane

NASA Astrophysics Data System (ADS)

Genova, J.; Dencheva-Zarkova, M.

2017-01-01

Elaiophylin is a new macrodiolide antibiotic, which is produced by the Streptomyces strains [1]. It displays biological activities against Gram-positive bacteria and fungi. The mode of action of this antibiotic has been attributed to an alteration of the membrane permeability. When this antibiotic is inserted into the bilayer membranes destabilization of the membrane and formation of ion-penetrable channels is observed. The macrodiolide antibiotic forms stable cation selective ion channels in synthetic lipid bilayer membranes. The aim of this work was to study the interactions of Elaiophylin with model bilayer membranes and to get information on the mechanical properties of lipid bilayers in presence of this antibiotic. Patch-clamp technique [2] were used in the study

Performance enhancement of pentacene-based organic thin-film transistors using 6,13-pentacenequinone as a carrier injection interlayer

NASA Astrophysics Data System (ADS)

Fan, Ching-Lin; Lin, Wei-Chun; Chen, Hao-Wei

2018-06-01

This work demonstrates pentacene-based organic thin-film transistors (OTFTs) fabricated by inserting a 6,13-pentacenequinone (PQ) carrier injection layer between the source/drain (S/D) metal Au electrodes and pentacene channel layer. Compared to devices without a PQ layer, the performance characteristics including field-effect mobility, threshold voltage, and On/Off current ratio were significantly improved for the device with a 5-nm-thick PQ interlayer. These improvements are attributed to significant reduction of hole barrier height at the Au/pentacene channel interfaces. Therefore, it is believed that using PQ as the carrier injection layer is a good candidate to improve the pentacene-based OTFTs electrical performance.

Multiple piece turbine airfoil

DOEpatents

Kimmel, Keith D

2010-11-09

A turbine airfoil, such as a rotor blade or a stator vane, for a gas turbine engine, the airfoil formed as a shell and spar construction with a plurality of hook shaped struts each mounted within channels extending in a spanwise direction of the spar and the shell to allow for relative motion between the spar and shell in the airfoil chordwise direction while also fanning a seal between adjacent cooling channels. The struts provide the seal as well as prevent bulging of the shell from the spar due to the cooling air pressure. The hook struts have a hooked shaped end and a rounded shaped end in order to insert the struts into the spar.

Experimental Evaluation of a SiPM-Based Scintillation Detector for MR-Compatible SPECT Systems

NASA Astrophysics Data System (ADS)

Busca, Paolo; Occhipinti, Michele; Trigilio, Paolo; Cozzi, Giulia; Fiorini, Carlo; Piemonte, Claudio; Ferri, Alessandro; Gola, Alberto; Nagy, Kálmán; Bükki, Tamás; Rieger, Jan

2015-10-01

In the present work we briefly describe the architecture of a photo-detection module, designed in the framework of the INSERT (INtegrated SPECT/MRI for Enhanced Stratification in Radio-chemoTherapy) project, supported by the European Community. We focus on two main elements of the module: the SiPM photo-detector unit and the multi-channel ASIC. These two components have been investigated with dedicated and independent setups to assess preliminary performance of INSERT architecture. In details, we designed a 25.30 mm ×25.85 mm tile, comprising 9 pixels, each one with an 8 mm ×8 mm active area. We developed an Anger camera to characterize the tile coupled to a CsI:Tl scintillator (6 mm thick). We measured an average spatial resolution (FWHM) of 2 mm in the central region of the Field of View and a 15.3% energy resolution using a 57Co source (122 keV), when the tile is cooled down to 0 ° C to reduce the impact of the dark count rate. Furthermore, we developed ANGUS, a 36-channels 0.35 μm CMOS technology ASIC designed to cope with input capacitance up to 5 nF, typical of large area SiPM pixels. The spectroscopic capability of single readout channels were evaluated by coupling an 8 mm ×8 mm pixel with a cylindrical CsI:Tl scintillator (8 mm diameter, 10 mm thickness). Energy resolution at room temperature provided values between 13% and 13.5% (FWHM) at the 122 keV line for the nine pixels.

Comparison of model and human observer performance in FFDM, DBT, and synthetic mammography

NASA Astrophysics Data System (ADS)

Ikejimba, Lynda; Glick, Stephen J.; Samei, Ehsan; Lo, Joseph Y.

2016-03-01

Reader studies are important in assessing breast imaging systems. The purpose of this work was to assess task-based performance of full field digital mammography (FFDM), digital breast tomosynthesis (DBT), and synthetic mammography (SM) using different phantom types, and to determine an accurate observer model for human readers. Images were acquired on a Hologic Selenia Dimensions system with a uniform and anthropomorphic phantom. A contrast detail insert of small, low-contrast disks was created using an inkjet printer with iodine-doped ink and inserted in the phantoms. The disks varied in diameter from 210 to 630 μm, and in contrast from 1.1% contrast to 2.2% in regular increments. Human and model observers performed a 4-alternative forced choice experiment. The models were a non-prewhitening matched filter with eye model (NPWE) and a channelized Hotelling observer with either Gabor channels (Gabor-CHO) or Laguerre-Gauss channels (LG-CHO). With the given phantoms, reader scores were higher in FFDM and DBT than SM. The structure in the phantom background had a bigger impact on outcome for DBT than for FFDM or SM. All three model observers showed good correlation with humans in the uniform background, with ρ between 0.89 and 0.93. However, in the structured background, only the CHOs had high correlation, with ρ=0.92 for Gabor-CHO, 0.90 for LG-CHO, and 0.77 for NPWE. Because results of any analysis can depend on the phantom structure, conclusions of modality performance may need to be taken in the context of an appropriate model observer and a realistic phantom.

First results from different investigations on MHD flow in multichannel U-Bends

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

Reimann, J.; Barleon, L.; Molokov, S.

1995-04-01

In electrically coupled multichannel ducts with a U-bend geometry, MHD effects can result in strongly non-uniform distributions of flow rates Q{sub i} and pressure drops {Delta}p{sub i} in the individual channels. A multichannel U-bend geometry is part of the KfK self-cooled Pb-17Li blanket design for a fusion reactor (radial-toroidal-radial channels). However, inserts are proposed which decouple electrically the radial channels. The multi-channel effects (MCDs) were investigated by (i) Screening test with InGaSn at LAS, Riga, and (ii) more detailed experiments with NaK at KfK, Karlsruhe. Different flow channel geometries and channel numbers between 1 and 5 were used. Hartmann numbersmore » and interaction parameters were varied between O {le} M {le} 2300 and O {le} N {le} 40000. In parallel, a theoretical analysis was performed, based on the method of core flow approximation (CFA) which is valid for M {r_arrow} {infinity} and N {r_arrow} {infinity}. Significant MCEs occur in all ducts with totally electrically coupled channels. For the mode {Delta}p{sub i} = const, the flow rates in the outer channels can become significantly larger than those in the inner channels. For Q{sub i} = const, the highest pressure drop occurs in the middle channel and the lowest in the outer channels. The CFA predicts correctly the ratios of the pressure drops of the single channels but gives lower values than observed experimentally. No marked MCE was found for flow geometry which is similar to the KfK design, i.e., a fairly uniform flow rate and pressure drop distribution was observed for all values of M and N.« less

Reduced expression of Na(v)1.6 sodium channels and compensation by Na(v)1.2 channels in mice heterozygous for a null mutation in Scn8a.

PubMed

Vega, Ana V; Henry, Diane L; Matthews, Gary

2008-09-05

The voltage-gated sodium channel alpha subunit Na(v)1.6, encoded by the Scn8a gene, accumulates at high density at mature nodes of Ranvier of myelinated axons, replacing the Na(v)1.2 channels found at nodes earlier in development. To investigate this preferential expression of Na(v)1.6 at adult nodes, we examined isoform-specific expression of sodium channels in mice heterozygous for a null mutation in Scn8a. Immunoblots from these +/- mice had 50% of the wild-type level of Na(v)1.6 protein, and their optic-nerve nodes of Ranvier had correspondingly less anti-Na(v)1.6 immunofluorescence. Protein level and nodal immunofluorescence of the Na(v)1.2 alpha subunit increased in Scn8a(+/-) mice, keeping total sodium channel expression approximately constant despite partial loss of Na(v)1.6 channels. The results are consistent with a model in which Na(v)1.6 and Na(v)1.2 compete for binding partners at sites of high channel density, such as nodes of Ranvier. We suggest that Na(v)1.6 channels normally occupy most of the molecular machinery responsible for channel clustering because they have higher binding affinity, and not because they are exclusively recognized by mechanisms for transport and insertion of sodium channels in myelinated axons. The reduced amount of Na(v)1.6 protein in Scn8a(+/-) mice is apparently insufficient to saturate the nodal binding sites, allowing Na(v)1.2 channels to compete more successfully.

Effects of Phenylalanine Substitutions in Gramicidin A on the Kinetics of Channel Formation in Vesicles and Channel Structure in SDS Micelles

PubMed Central

Jordan, J. B.; Easton, P. L.; Hinton, J. F.

2005-01-01

The common occurrence of Trp residues at the aqueous-lipid interface region of transmembrane channels is thought to be indicative of its importance for insertion and stabilization of the channel in membranes. To further investigate the effects of Trp→Phe substitution on the structure and function of the gramicidin channel, four analogs of gramicidin A have been synthesized in which the tryptophan residues at positions 9, 11, 13, and 15 are sequentially replaced with phenylalanine. The three-dimensional structure of each viable analog has been determined using a combination of two-dimensional NMR techniques and distance geometry-simulated annealing structure calculations. These phenylalanine analogs adopt a homodimer motif, consisting of two β6.3 helices joined by six hydrogen bonds at their NH2-termini. The replacement of the tryptophan residues does not have a significant effect on the backbone structure of the channels when compared to native gramicidin A, and only small effects are seen on side-chain conformations. Single-channel conductance measurements have shown that the conductance and lifetime of the channels are significantly affected by the replacement of the tryptophan residues (Wallace, 2000; Becker et al., 1991). The variation in conductance appears to be caused by the sequential removal of a tryptophan dipole, thereby removing the ion-dipole interaction at the channel entrance and at the ion binding site. Channel lifetime variations appear to be related to changing side chain-lipid interactions. This is supported by data relating to transport and incorporation kinetics. PMID:15501932

Effects of phenylalanine substitutions in gramicidin A on the kinetics of channel formation in vesicles and channel structure in SDS micelles.

PubMed

Jordan, J B; Easton, P L; Hinton, J F

2005-01-01

The common occurrence of Trp residues at the aqueous-lipid interface region of transmembrane channels is thought to be indicative of its importance for insertion and stabilization of the channel in membranes. To further investigate the effects of Trp-->Phe substitution on the structure and function of the gramicidin channel, four analogs of gramicidin A have been synthesized in which the tryptophan residues at positions 9, 11, 13, and 15 are sequentially replaced with phenylalanine. The three-dimensional structure of each viable analog has been determined using a combination of two-dimensional NMR techniques and distance geometry-simulated annealing structure calculations. These phenylalanine analogs adopt a homodimer motif, consisting of two beta6.3 helices joined by six hydrogen bonds at their NH2-termini. The replacement of the tryptophan residues does not have a significant effect on the backbone structure of the channels when compared to native gramicidin A, and only small effects are seen on side-chain conformations. Single-channel conductance measurements have shown that the conductance and lifetime of the channels are significantly affected by the replacement of the tryptophan residues (Wallace, 2000; Becker et al., 1991). The variation in conductance appears to be caused by the sequential removal of a tryptophan dipole, thereby removing the ion-dipole interaction at the channel entrance and at the ion binding site. Channel lifetime variations appear to be related to changing side chain-lipid interactions. This is supported by data relating to transport and incorporation kinetics.

Quantum biological channel modeling and capacity calculation.

PubMed

Djordjevic, Ivan B

2012-12-10

Quantum mechanics has an important role in photosynthesis, magnetoreception, and evolution. There were many attempts in an effort to explain the structure of genetic code and transfer of information from DNA to protein by using the concepts of quantum mechanics. The existing biological quantum channel models are not sufficiently general to incorporate all relevant contributions responsible for imperfect protein synthesis. Moreover, the problem of determination of quantum biological channel capacity is still an open problem. To solve these problems, we construct the operator-sum representation of biological channel based on codon basekets (basis vectors), and determine the quantum channel model suitable for study of the quantum biological channel capacity and beyond. The transcription process, DNA point mutations, insertions, deletions, and translation are interpreted as the quantum noise processes. The various types of quantum errors are classified into several broad categories: (i) storage errors that occur in DNA itself as it represents an imperfect storage of genetic information, (ii) replication errors introduced during DNA replication process, (iii) transcription errors introduced during DNA to mRNA transcription, and (iv) translation errors introduced during the translation process. By using this model, we determine the biological quantum channel capacity and compare it against corresponding classical biological channel capacity. We demonstrate that the quantum biological channel capacity is higher than the classical one, for a coherent quantum channel model, suggesting that quantum effects have an important role in biological systems. The proposed model is of crucial importance towards future study of quantum DNA error correction, developing quantum mechanical model of aging, developing the quantum mechanical models for tumors/cancer, and study of intracellular dynamics in general.

Modulation of Crystal Surface and Lattice by Doping: Achieving Ultrafast Metal-Ion Insertion in Anatase TiO2.

PubMed

Wang, Hsin-Yi; Chen, Han-Yi; Hsu, Ying-Ya; Stimming, Ulrich; Chen, Hao Ming; Liu, Bin

2016-10-26

We report that an ultrafast kinetics of reversible metal-ion insertion can be realized in anatase titanium dioxide (TiO 2 ). Niobium ions (Nb 5+ ) were carefully chosen to dope and drive anatase TiO 2 into very thin nanosheets standing perpendicularly onto transparent conductive electrode (TCE) and simultaneously construct TiO 2 with an ion-conducting surface together with expanded ion diffusion channels, which enabled ultrafast metal ions to diffuse across the electrolyte/solid interface and into the bulk of TiO 2 . To demonstrate the superior metal-ion insertion rate, the electrochromic features induced by ion intercalation were examined, which exhibited the best color switching speed of 4.82 s for coloration and 0.91 s for bleaching among all reported nanosized TiO 2 devices. When performed as the anode for the secondary battery, the modified TiO 2 was capable to deliver a highly reversible capacity of 61.2 mAh/g at an ultrahigh specific current rate of 60 C (10.2 A/g). This fast metal-ion insertion behavior was systematically investigated by the well-controlled electrochemical approaches, which quantitatively revealed both the enhanced surface kinetics and bulk ion diffusion rate. Our study could provide a facile methodology to modulate the ion diffusion kinetics for metal oxides.

Non-blocking four-port optical router based on thermooptic silicon microrings

NASA Astrophysics Data System (ADS)

Dang, Pei-pei; Li, Cui-ting; Zheng, Wen-xue; Zheng, Chuan-tao; Wang, Yi-ding

2016-07-01

By using silicon-on-insulator (SOI) platform, 12 channel waveguides, and four parallel-coupling one-microring resonator routing elements, a non-blocking four-port optical router is proposed. Structure design and optimization are performed on the routing elements at 1 550 nm. At drop state with a power consumption of 0 mW, the insertion loss of the drop port is less than 1.12 dB, and the crosstalk between the two output ports is less than -28 dB; at through state with a power consumption of 22 mW, the insertion loss of the through port is less than 0.45 dB, and the crosstalk between the two output ports is below -21 dB. Routing topology and function are demonstrated for the four-port optical router. The router can work at nine non-blocking routing states using the thermo-optic (TO) effect of silicon for tuning the resonance of each switching element. Detailed characterizations are presented, including output spectrum, insertion loss, and crosstalk. According to the analysis on all the data links of the router, the insertion loss is within the range of 0.13—3.36 dB, and the crosstalk is less than -19.46 dB. The router can meet the need of large-scale optical network-on-chip (ONoC).

Density functional theory studies of TiO2 for photocatalysis and Li storage applications

NASA Astrophysics Data System (ADS)

Kim, Yong-Hoon; Lee, Ji Il; Lee, Dong Ki; Lee, Gyu Heon; Kang, Jeung Ku

We present two theory-experiment collaboration studies of anatase TiO2 for energy applications. First, we discuss a hydrogen-nitrogen co-doped TiO2 (HN-TiO2) as a photocatalyst, and show that the interstitially introduced HN contributes to the increase of solar-to-fuel conversion efficiency. We find that the variation of valence band maximum (VBM) of NH-TiO2 extends the photoactive spectrum to the visible light, and argue that created mid-gap states produce efficient electron and hole conduction channels. Next, we consider experimentally fabricated hierarchical TiO2 nanocrystals integrated with binder-free porous graphene (PG) network foam for a Li storage application. It was found that the TiO2-PG facilitated rapid ionic transfer during the Li-ion insertion/extraction process. We clarify the mechanisms by showing that Li ion migration into the TiO2-PG interface stabilize the binder-free oxide-graphene interface. Atomistic mechanism of Li ion insertion and migration is discussed by comparing cases between an isolated Li ion, when the crowding effect is included, and when the surface Li ions are present. We found that the supply of additional surface Li ions significantly reduce the Li insertion barrier, driving a spontaneous domino-like concerted Li insertion at the oxide surface region.

Modiolus-Hugging Intracochlear Electrode Array with Shape Memory Alloy

PubMed Central

Min, Kyou Sik; Lim, Yoon Seob; Park, Se-Ik; Kim, Sung June

2013-01-01

In the cochlear implant system, the distance between spiral ganglia and the electrodes within the volume of the scala tympani cavity significantly affects the efficiency of the electrical stimulation in terms of the threshold current level and spatial selectivity. Because the spiral ganglia are situated inside the modiolus, the central axis of the cochlea, it is desirable that the electrode array hugs the modiolus to minimize the distance between the electrodes and the ganglia. In the present study, we propose a shape-memory-alloy-(SMA-) embedded intracochlear electrode which gives a straight electrode a curved modiolus-hugging shape using the restoration force of the SMA as triggered by resistive heating after insertion into the cochlea. An eight-channel ball-type electrode array is fabricated with an embedded titanium-nickel SMA backbone wire. It is demonstrated that the electrode array changes its shape in a transparent plastic human cochlear model. To verify the safe insertion of the electrode array into the human cochlea, the contact pressures during insertion at the electrode tip and the contact pressures over the electrode length after insertion were calculated using a 3D finite element analysis. The results indicate that the SMA-embedded electrode is functionally and mechanically feasible for clinical applications. PMID:23762181

Efficacy of a Novel Narrow Knife with Water Jet Function for Colorectal Endoscopic Submucosal Dissection

PubMed Central

Inada, Yutaka; Rani, Rafiz Abdul; Naito, Yuji; Azuma, Takeshi; Itoh, Yoshito

2017-01-01

Backgrounds With respect to the knife's design in colorectal endoscopic submucosal dissection (ESD), diameter, water jet function, and electric power are important because these relate to efficient dissection. In this study, we analyzed a novel, narrow ball tip-typed ESD knife with water jet function (Flush knife BT-S, diameter: 2.2 mm, length: 2000 mm, Fujifilm Co., Tokyo, Japan) compared to a regular diameter knife (Flush knife BT, diameter: 2.6 mm, length: 1800 mm). Methods In laboratory and clinical research, electric power, knife insertion time, vacuum/suction amount with knife in the endoscopic channel, and water jet function were analyzed. We used a knife 2.0 mm long for BT-S and BT knives. Results The BT-S showed faster mean knife insertion time (sec) and better vacuum amount (ml/min) compared to the BT (insertion time: 16.7 versus 21.6, p < 0.001, vacuum amount: 38.0 versus 14.0, p < 0.01). Additionally, the water jet function of the BT-S was not inferior. In 39 colorectal ESD cases in two institutions, there were mean 4.7 times (range: 1–28) of knife insertion. Suction under knife happened 59% (23/39) and suction of fluid could be done in 100%. Conclusions Our study showed that the narrow knife allows significantly faster knife insertion, better vacuum function, and effective clinical results. PMID:29081793

The role of lipid composition for insertion and stabilization of amino acids in membranes

NASA Astrophysics Data System (ADS)

Johansson, Anna C. V.; Lindahl, Erik

2009-05-01

While most membrane protein helices are clearly hydrophobic, recent experiments have indicated that it is possible to insert marginally hydrophobic helices into bilayers and have suggested apparent in vivo free energies of insertion for charged residues that are low, e.g., a few kcals for arginine. In contrast, a number of biophysical simulation studies have predicted that the bilayer interior is close to a pure hydrophobic environment with large penalties for hydrophilic amino acids—and yet the experimental scales do significantly better at predicting actual membrane proteins from sequence. Here, we have systematically studied the dependence of the free energy profiles on lipid properties, including tail length, saturation, headgroup hydrogen bond strength, and charge, both to see to whether the in vivo insertion can be explained in whole or part from lipid composition of the endoplasmic reticulum (ER) membranes, and if the solvation properties can help interpret how protein function depends on the lipids. We find that lipid charge is important to stabilize charged amino acids inside the bilayer (with implications, e.g., for ion channels), that thicker bilayers have higher solvation costs for hydrophilic side chains, and that headgroup hydrogen bond strength determines how adaptive the lipids are as a hydrophobic/hydrophilic solvent. None of the different free energy profiles are even close to the low apparent in vivo insertion cost, which suggests that regardless of the specific ER membrane composition the current experimental results cannot be explained by normal lipid-type variation.

The TonB-dependent Transporter FhuA in Planar Lipid Bilayers: partial exit of its plug from the barrel

PubMed Central

Udho, Eshwar; Jakes, Karen S.; Finkelstein, Alan

2012-01-01

TonB-dependent transporters (TBDTs), which transport iron-chelating siderophores and vitamin B12 across the outer membrane of gram negative bacteria, share a conserved architecture of a 22-stranded beta-barrel with an amino-terminal plug domain occluding the barrel. We previously reported that we could induce TBDTs to reversibly open in planar lipid bilayers via the use of urea and that these channels were responsive to physiological concentrations of ligands. Here we report that in the presence of urea, trypsin can cleave the amino-terminal 67 residues of the plug of the TonB-dependent transporter FhuA, as assessed by gel shift and mass spectrometry assays. On the bilayer, trypsin treatment in the presence of urea resulted in the induced conductance no longer being reversed upon removal of urea, suggesting that urea opens intact FhuA channels by pulling the plug at least partly out of the barrel, and that removal of the urea then allows reinsertion of the plug into the barrel. When expressed separately, the FhuA plug domain was found to be a mostly unfolded structure that was able to occlude isolated FhuA beta-barrels inserted into the membrane. Thus, although folded in the barrel, the plug need not be folded upon exiting the barrel. The rate of insertion of the beta-barrels into the membrane was tremendously increased in the presence of an osmotic gradient provided by either urea or glycerol. Negative staining electron microscopy showed that FhuA in a detergent solution formed vesicles, thus explaining why an osmotic gradient promoted the insertion of FhuA into membranes. PMID:22846061

A Diffusion-Based and Dynamic 3D-Printed Device That Enables Parallel in Vitro Pharmacokinetic Profiling of Molecules

PubMed Central

Lockwood, Sarah Y.; Meisel, Jayda E.; Monsma, Frederick J.; Spence, Dana M.

2016-01-01

The process of bringing a drug to market involves many steps, including the preclinical stage, where various properties of the drug candidate molecule are determined. These properties, which include drug absorption, distribution, metabolism, and excretion, are often displayed in a pharmacokinetic (PK) profile. While PK profiles are determined in animal models, in vitro systems that model in vivo processes are available, although each possesses shortcomings. Here, we present a 3D-printed, diffusion-based, and dynamic in vitro PK device. The device contains six flow channels, each with integrated porous membrane-based insert wells. The pores of these membranes enable drugs to freely diffuse back and forth between the flow channels and the inserts, thus enabling both loading and clearance portions of a standard PK curve to be generated. The device is designed to work with 96-well plate technology and consumes single-digit milliliter volumes to generate multiple PK profiles, simultaneously. Generation of PK profiles by use of the device was initially performed with fluorescein as a test molecule. Effects of such parameters as flow rate, loading time, volume in the insert well, and initial concentration of the test molecule were investigated. A prediction model was generated from this data, enabling the user to predict the concentration of the test molecule at any point along the PK profile within a coefficient of variation of ~5%. Depletion of the analyte from the well was characterized and was determined to follow first-order rate kinetics, indicated by statistically equivalent (p > 0.05) depletion half-lives that were independent of the starting concentration. A PK curve for an approved antibiotic, levofloxacin, was generated to show utility beyond the fluorescein test molecule. PMID:26727249

Concurrent electrophysiology and TPM/OCT imaging of long-term implanted electrodes (Conference Presentation)

NASA Astrophysics Data System (ADS)

Hammer, Daniel X.; Gao, Yu-Rong; Ye, Meijun; Welle, Cristin G.

2017-02-01

Microelectrodes implanted in the brain cause mechanical damage to the tissue that mediate neuroinflammation and eventual encapsulation by microglia and astrocytes. Electrophysiological signals recorded from implants used in brain-computer interfaces (BCI) degrade over time, limiting their usefulness, but the precise causes and progression are not fully understood. We are investigating the dynamics of brain morphological changes and neuroinflammation with a multimodal approach to better understand the potential causes of implant failure. We performed weekly optical coherence tomography (OCT)-guided two-photon microscopy (TPM) in the region around microelectrodes inserted under a cranial window concurrent with electrophysiological recordings. Transgenic mouse cohorts studied include Thy1-YFP, Cx3cr1, and GFAP-GFP to image neurons, microglia, and astrocytes, respectively. Single-shank, 16-channel, Michigan-style microelectrodes were inserted under the window at a 15-20° angle with an insertion depth up to cortical layer 5. Single-unit and local field potential (LFP) recordings were collected for 15 minutes while the animals moved freely in their home cages. Cellular and vascular morphology were monitored using TPM and OCT at timepoints matched to the recordings. In preliminary data, we observed a decay of neural firing rates in most of the channels after implantation. The relationship between electrophysiological measures (e.g., neural firing rate, LFP power) and neural/vascular morphological measurements (e.g., cell density, glial migration, blood flow changes) will be quantified. The multimodal approach combining electrophysiology and optical imaging provides a broader picture of the multifactorial nature of the response to implanted electrodes. Understanding and accounting for the response may lead to better BCI designs and approaches.

Two distinct voltage-sensing domains control voltage sensitivity and kinetics of current activation in CaV1.1 calcium channels.

PubMed

Tuluc, Petronel; Benedetti, Bruno; Coste de Bagneaux, Pierre; Grabner, Manfred; Flucher, Bernhard E

2016-06-01

Alternative splicing of the skeletal muscle CaV1.1 voltage-gated calcium channel gives rise to two channel variants with very different gating properties. The currents of both channels activate slowly; however, insertion of exon 29 in the adult splice variant CaV1.1a causes an ∼30-mV right shift in the voltage dependence of activation. Existing evidence suggests that the S3-S4 linker in repeat IV (containing exon 29) regulates voltage sensitivity in this voltage-sensing domain (VSD) by modulating interactions between the adjacent transmembrane segments IVS3 and IVS4. However, activation kinetics are thought to be determined by corresponding structures in repeat I. Here, we use patch-clamp analysis of dysgenic (CaV1.1 null) myotubes reconstituted with CaV1.1 mutants and chimeras to identify the specific roles of these regions in regulating channel gating properties. Using site-directed mutagenesis, we demonstrate that the structure and/or hydrophobicity of the IVS3-S4 linker is critical for regulating voltage sensitivity in the IV VSD, but by itself cannot modulate voltage sensitivity in the I VSD. Swapping sequence domains between the I and the IV VSDs reveals that IVS4 plus the IVS3-S4 linker is sufficient to confer CaV1.1a-like voltage dependence to the I VSD and that the IS3-S4 linker plus IS4 is sufficient to transfer CaV1.1e-like voltage dependence to the IV VSD. Any mismatch of transmembrane helices S3 and S4 from the I and IV VSDs causes a right shift of voltage sensitivity, indicating that regulation of voltage sensitivity by the IVS3-S4 linker requires specific interaction of IVS4 with its corresponding IVS3 segment. In contrast, slow current kinetics are perturbed by any heterologous sequences inserted into the I VSD and cannot be transferred by moving VSD I sequences to VSD IV. Thus, CaV1.1 calcium channels are organized in a modular manner, and control of voltage sensitivity and activation kinetics is accomplished by specific molecular mechanisms within the IV and I VSDs, respectively. © 2016 Tuluc et al.

Two distinct voltage-sensing domains control voltage sensitivity and kinetics of current activation in CaV1.1 calcium channels

PubMed Central

Tuluc, Petronel; Benedetti, Bruno; Coste de Bagneaux, Pierre; Grabner, Manfred

2016-01-01

Alternative splicing of the skeletal muscle CaV1.1 voltage-gated calcium channel gives rise to two channel variants with very different gating properties. The currents of both channels activate slowly; however, insertion of exon 29 in the adult splice variant CaV1.1a causes an ∼30-mV right shift in the voltage dependence of activation. Existing evidence suggests that the S3–S4 linker in repeat IV (containing exon 29) regulates voltage sensitivity in this voltage-sensing domain (VSD) by modulating interactions between the adjacent transmembrane segments IVS3 and IVS4. However, activation kinetics are thought to be determined by corresponding structures in repeat I. Here, we use patch-clamp analysis of dysgenic (CaV1.1 null) myotubes reconstituted with CaV1.1 mutants and chimeras to identify the specific roles of these regions in regulating channel gating properties. Using site-directed mutagenesis, we demonstrate that the structure and/or hydrophobicity of the IVS3–S4 linker is critical for regulating voltage sensitivity in the IV VSD, but by itself cannot modulate voltage sensitivity in the I VSD. Swapping sequence domains between the I and the IV VSDs reveals that IVS4 plus the IVS3–S4 linker is sufficient to confer CaV1.1a-like voltage dependence to the I VSD and that the IS3–S4 linker plus IS4 is sufficient to transfer CaV1.1e-like voltage dependence to the IV VSD. Any mismatch of transmembrane helices S3 and S4 from the I and IV VSDs causes a right shift of voltage sensitivity, indicating that regulation of voltage sensitivity by the IVS3–S4 linker requires specific interaction of IVS4 with its corresponding IVS3 segment. In contrast, slow current kinetics are perturbed by any heterologous sequences inserted into the I VSD and cannot be transferred by moving VSD I sequences to VSD IV. Thus, CaV1.1 calcium channels are organized in a modular manner, and control of voltage sensitivity and activation kinetics is accomplished by specific molecular mechanisms within the IV and I VSDs, respectively. PMID:27185857

The role of receptor topology in the vitamin D3 uptake and Ca{sup 2+} response systems

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

Morrill, Gene A., E-mail: gene.morrill@einstein.yu.edu; Kostellow, Adele B.; Gupta, Raj K.

The steroid hormone, vitamin D{sub 3}, regulates gene transcription via at least two receptors and initiates putative rapid response systems at the plasma membrane. The vitamin D receptor (VDR) binds vitamin D{sub 3} and a second receptor, importin-4, imports the VDR-vitamin D{sub 3} complex into the nucleus via nuclear pores. Here we present evidence that the Homo sapiens VDR homodimer contains two transmembrane (TM) helices ({sup 327}E – D{sup 342}), two TM “half-helix” ({sup 264}K − N{sup 276}), one or more large channels, and 16 cholesterol binding (CRAC/CARC) domains. The importin-4 monomer exhibits 3 pore-lining regions ({sup 226}E – L{supmore » 251}; {sup 768}V – G{sup 783}; {sup 876}S – A{sup 891}) and 16 CRAC/CARC domains. The MEMSAT algorithm indicates that VDR and importin-4 may not be restricted to cytoplasm and nucleus. VDR homodimer TM helix-topology predicts insertion into the plasma membrane, with two 84 residue C-terminal regions being extracellular. Similarly, MEMSAT predicts importin-4 insertion into the plasma membrane with 226 residue extracellular N-terminal regions and 96 residue C-terminal extracellular loops; with the pore-lining regions contributing gated Ca{sup 2+} channels. The PoreWalker algorithm indicates that, of the 427 residues in each VDR monomer, 91 line the largest channel, including two vitamin D{sub 3} binding sites and residues from both the TM helix and “half-helix”. Cholesterol-binding domains also extend into the channel within the ligand binding region. Programmed changes in bound cholesterol may regulate both membrane Ca{sup 2+} response systems and vitamin D{sub 3} uptake as well as receptor internalization by the endomembrane system culminating in uptake of the vitamin D{sub 3}-VDR-importin-4 complex into the nucleus.« less

Advanced Electron Optics for Vibrational Spectroscopy.

DTIC Science & Technology

1987-10-02

observations of vibrational losses measured 0 2z b n t l o a i r u e h s i by inelastic elctron scattering from surfaces. The basic dif- ference...AFOSR-86-6291 UNCLASSIFIED F/Ci 26/14 U EhEilEEEEEBI / E /EEiEEElh E /EEEE~h R-~ ~ 3 -00 0 0 S *...S :04 *.: UNA A ASSIFIED 469 RT CLASSIFICATION OF THIS...Surfaces", J.L. Erskine, American Vacuum Society Lecture, Texas A&M Unversity, College Station, Texas, April 24,1984. e "Electron Energy Loss Studies of

Sub-cellular distribution and translocation of TRP channels.

PubMed

Toro, Carlos A; Arias, Luis A; Brauchi, Sebastian

2011-01-01

Cellular electrical activity is the result of a highly complex processes that involve the activation of ion channel proteins. Ion channels make pores on cell membranes that rapidly transit between conductive and non-conductive states, allowing different ions to flow down their electrochemical gradients across cell membranes. In the case of neuronal cells, ion channel activity orchestrates action potentials traveling through axons, enabling electrical communication between cells in distant parts of the body. Somatic sensation -our ability to feel touch, temperature and noxious stimuli- require ion channels able to sense and respond to our peripheral environment. Sensory integration involves the summing of various environmental cues and their conversion into electrical signals. Members of the Transient Receptor Potential (TRP) family of ion channels have emerged as important mediators of both cellular sensing and sensory integration. The regulation of the spatial and temporal distribution of membrane receptors is recognized as an important mechanism for controlling the magnitude of the cellular response and the time scale on which cellular signaling occurs. Several studies have shown that this mechanism is also used by TRP channels to modulate cellular response and ultimately fulfill their physiological function as sensors. However, the inner-working of this mode of control for TRP channels remains poorly understood. The question of whether TRPs intrinsically regulate their own vesicular trafficking or weather the dynamic regulation of TRP channel residence on the cell surface is caused by extrinsic changes in the rates of vesicle insertion or retrieval remain open. This review will examine the evidence that sub-cellular redistribution of TRP channels plays an important role in regulating their activity and explore the mechanisms that control the trafficking of vesicles containing TRP channels.

Evaluation of stress stabilities in amorphous In-Ga-Zn-O thin-film transistors: Effect of passivation with Si-based resin

NASA Astrophysics Data System (ADS)

Ochi, Mototaka; Hino, Aya; Goto, Hiroshi; Hayashi, Kazushi; Fujii, Mami N.; Uraoka, Yukiharu; Kugimiya, Toshihiro

2018-02-01

Fabrication process conditions of a passivation (PV) layer correlated with stress stabilities of amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs). In etch-stop layer (ESL)-TFTs, by inserting a Si-based resin between SiN x and SiO x PV layers, the peak intensity in the photoinduced transient spectroscopy (PITS) spectrum was notably reduced. This suggested the suppression of hydrogen incorporation into a-IGZO, which led to the improvement of stability under negative bias thermal illumination stress (NBTIS). In contrast, the hydrogen-related defects in the a-IGZO were easily formed by the back-channel etch (BCE) process. Furthermore, it was found that, under NBTIS, the transfer curves of the BCE-TFTs shifted in parallel owing to the positive fixed charge located in the back channel of the a-IGZO TFTs. The hump-shaped shift increased with stress time. This is because hydrogen atoms located at the back-channel surfaces of the a-IGZO and/or PV layers were incorporated into the channel region of the BCE-TFTs and induced the hydrogen-related defects.

A portable multi-channel recording system for analysis of acceleration and angular velocity in six dimension.

PubMed

Yamashita, M; Yamashita, A; Ishii, T; Naruo, Y; Nagatomo, M

1998-11-01

A portable recording system was developed for analysis of more than three analog signals collected in field works. Stereo audio recorder, available as consumer products, was made use for a core cornponent of the system. For the two tracks of recording, a multiplexed analog signal is stored on one track, and reference code on the other track. The reference code indicates the start of one cycle for multiplexing and swiching point of each channel. Multiplexed signal is playbacked and decoded with a reference of the code to reconstruct original profiles of the signal. Since commercial stereo recorders have cut DC component off, a fixed reference voltage is inserted in the sequence of multiplexing. Change of voltage at switching from the reference to the data channel is measured from playbacked signal to get the original data with its DC component. Movement of vehicles and human head were analyzed by the system. It was verified to be capable to record and analyze multi-channel signal at a sampling rate more than 10Hz.

Steam exit flow design for aft cavities of an airfoil

DOEpatents

Storey, James Michael; Tesh, Stephen William

2002-01-01

Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.

Analysis of nanoscale two-phase flow of argon using molecular dynamics

NASA Astrophysics Data System (ADS)

Verma, Abhishek Kumar; Kumar, Rakesh

2014-12-01

Two phase flows through micro and nanochannels have attracted a lot of attention because of their immense applicability to many advanced fields such as MEMS/NEMS, electronic cooling, bioengineering etc. In this work, a molecular dynamics simulation method is employed to study the condensation process of superheated argon vapor force driven flow through a nanochannel combining fluid flow and heat transfer. A simple and effective particle insertion method is proposed to model phase change of argon based on non-periodic boundary conditions in the simulation domain. Starting from a crystalline solid wall of channel, the condensation process evolves from a transient unsteady state where we study the influence of different wall temperatures and fluid wall interactions on interfacial and heat transport properties of two phase flows. Subsequently, we analyzed transient temperature, density and velocity fields across the channel and their dependency on varying wall temperature and fluid wall interaction, after a dynamic equilibrium is achieved in phase transition. Quasi-steady nonequilibrium temperature profile, heat flux and interfacial thermal resistance were analyzed. The results demonstrate that the molecular dynamics method, with the proposed particle insertion method, effectively solves unsteady nonequilibrium two phase flows at nanoscale resolutions whose interphase between liquid and vapor phase is typically of the order of a few molecular diameters.

Peptides at Membrane Surfaces and their Role in Prebiotic Evolution

NASA Technical Reports Server (NTRS)

Pohorille, Andrew; Wilson, Michael A.; Chipot, Christophe; Fonda, Mark (Technical Monitor)

2002-01-01

Protocells had to transport ions and organic matter across membranes separating the interior of the cell from the environment, capture and utilize energy and transduce environmental signals. In a series of detailed, molecular-level computer simulations we show how these peptides in contact with membranes can acquire ordered structures and functions. We have investigated the stability of a simple alpha-helical peptide containing Leucine (L) and Serine (S) of the form (LSLLLSL)3 in a model membrane system. The parallel in-plane state is the most stable configuration. The transmembrane state is metastable, and about 15 kcal/mol is required to insert the peptide into the membrane. We investigated dimes of both (LSLLLSL)3 and glycophorin A, and show how the free energy of helix association can, at least partially, offset the free energy of insertion. We have also investigated the transmembrane pore of the influenza M2 protein. This aggregate of four identical alpha-helices, each built of 25 amino acids, forms an efficient and selective voltage-gated proton channel. Our simulations explain the gating mechanism, which can involve strands of hydrogen-bonded water through the pore or proton transfer through tautomerization of protein residues. The channel can be re-engineered to act as a simple proton pump.

High-pressure alchemy on a small-pore zeolite

NASA Astrophysics Data System (ADS)

Lee, Y.

2011-12-01

While an ever-expanding variety of zeolites with a wide range of framework topology is available, it is desirable to have a way to tailor the chemistry of the zeolitic nanopores for a given framework topology via controlling both the coordination-inclusion chemistry and framework distortion/relaxation. This is, however, subjected to the ability of a zeolitic nanopore to allow the redistribution of cations-water assembly and/or insertion of foreign molecules into the pores and channels. Small-pore zeolites such as natrolite (Na16Al16Si24O80x16H2O), however, have been known to show very limited capacity for any changes in the confinement chemistry. We have recently shown that various cation-exchanged natrolites can be prepared under modest conditions from natural sodium natrolite and exhibit cation-dependent volume expansions by up to 18.5% via converting the elliptical channels into progressively circular ones. Here, we show that pressure can be used as a unique and clean tool to further manipulate the chemistry of the natrolite nanopores. Our recent crystallographic and spectroscopic studies of pressure-insertion of foreign molecules, trivalent-cation exchange under pressure, and pressure-induced inversion of cation-water coordination and pore geometry in various cation-exchanged natrolites will be presented.

Functional materials for breeding blankets—status and developments

NASA Astrophysics Data System (ADS)

Konishi, S.; Enoeda, M.; Nakamichi, M.; Hoshino, T.; Ying, A.; Sharafat, S.; Smolentsev, S.

2017-09-01

The development of tritium breeder, neutron multiplier and flow channel insert materials for the breeding blanket of the DEMO reactor is reviewed. Present emphasis is on the ITER test blanket module (TBM); lithium metatitanate (Li2TiO3) and lithium orthosilicate (Li4SiO4) pebbles have been developed by leading TBM parties. Beryllium pebbles have been selected as the neutron multiplier. Good progress has been made in their fabrication; however, verification of the design by experiments is in the planning stage. Irradiation data are also limited, but the decrease in thermal conductivity of beryllium due to irradiation followed by swelling is a concern. Tests at ITER are regarded as a major milestone. For the DEMO reactor, improvement of the breeder has been attempted to obtain a higher lithium content, and Be12Ti and other beryllide intermetallic compounds that have superior chemical stability have been studied. LiPb eutectic has been considered as a DEMO blanket in the liquid breeder option and is used as a coolant to achieve a higher outlet temperature; a SiC flow channel insert is used to prevent magnetohydrodynamic pressure drop and corrosion. A significant technical gap between ITER TBM and DEMO is recognized, and the world fusion community is working on ITER TBM and DEMO blanket development in parallel.

A novel, inexpensive, double lumen suprapubic catheter for urodynamics.

PubMed

Wagner, Andrew A; Godley, Margaret L; Duffy, Patrick G; Ransley, Philip G

2004-03-01

We describe a novel, double lumen, intravesical, suprapubic catheter designed to meet the requirements of pediatric urodynamics that is easy to use and has minimal complications. A commercially available 10Fr pediatric suprapubic pigtail catheter forms the outer lumen for instilling filling media. A 16 gauge epidural catheter is inserted through the outer catheter providing an inner lumen for measuring intravesical pressures. The resultant double-lumen catheter is inserted suprapubically using a peel away needle supplied with the 10Fr catheter, with the patient under general anesthetic. The catheter has been used for 15 years in more than 700 patients with good reliability and few complications. The concentric construction of the double lumens and the rigidity of the inner intravesical pressure channel ensure there is no transmission of pressure from the filling channel to the inner lumen. The catheter has a circular cross section and a pigtail distal end which help to retain it within the bladder. There is low resistance to filling that allows adequate filling rates to be achieved by gravity rather than necessitating a pump. The catheter is easily made from readily available components and is less expensive than other double-lumen catheters suitable for suprapubic use. A reliable, double lumen catheter that fulfills criteria not found in commercially available alternatives can be inexpensively made for urodynamics.

Design and preliminary analysis of a vaginal inserter for speculum-free cervical cancer screening

PubMed Central

Agudogo, Júlia; Krieger, Marlee S.; Miros, Robert; Proeschold-Bell, Rae Jean; Schmitt, John W.; Ramanujam, Nimmi

2017-01-01

Objective Cervical cancer screening usually requires use of a speculum to provide a clear view of the cervix. The speculum is one potential barrier to screening due to fear of pain, discomfort and embarrassment. The aim of this paper is to present and demonstrate the feasibility of a tampon-sized inserter and the POCkeT Colposcope, a miniature pen sized-colposcope, for comfortable, speculum-free and potentially self-colposcopy. Study design We explored different designs using 3D computer-aided design (CAD) software and performed mechanical testing simulations on each. Designs were rapid prototyped and tested using a custom vaginal phantom across a range of vaginal pressures and uterine tilts to select an optimal design. Two final designs were tested with fifteen volunteers to assess cervix visualization, comfort and usability compared to the speculum and the optimal design, the curved-tip inserter, was selected for testing in volunteers. Results We present a vaginal inserter as an alternative to the standard speculum for use with the POCkeT Colposcope. The device has a slim tubular body with a funnel-like curved tip measuring approximately 2.5 cm in diameter. The inserter has a channel through which a 2 megapixel (MP) mini camera with LED illumination fits to enable image capture. Mechanical finite element testing simulations with an applied pressure of 15 cm H2O indicated a high factor of safety (90.9) for the inserter. Testing of the device with a custom vaginal phantom, across a range of supine vaginal pressures and uterine tilts (retroverted, anteverted and sideverted), demonstrated image capture with a visual area comparable to the speculum for a normal/axial positioned uteri and significantly better than the speculum for anteverted and sideverted uteri (p<0.00001). Volunteer studies with self-insertion and physician-assisted cervix image capture showed adequate cervix visualization for 83% of patients. In addition, questionnaire responses from volunteers indicated a 92.3% overall preference for the inserter over the speculum and all indicated that the inserter was more comfortable than the speculum. The inserter provides a platform for self-cervical cancer screening and also enables acetic acid/Lugol’s iodine application and insertion of swabs for Pap smear sample collection. Conclusion This study demonstrates the feasibility of an inserter and miniature-imaging device for comfortable cervical image capture of women with potential for synergistic HPV and Pap smear sample collection. PMID:28562669

Electric-acoustic pitch comparisons in single-sided-deaf cochlear implant users: frequency-place functions and rate pitch.

PubMed

Schatzer, Reinhold; Vermeire, Katrien; Visser, Daniel; Krenmayr, Andreas; Kals, Mathias; Voormolen, Maurits; Van de Heyning, Paul; Zierhofer, Clemens

2014-03-01

Eight cochlear implant users with near-normal hearing in their non-implanted ear compared pitch percepts for pulsatile electric and acoustic pure-tone stimuli presented to the two ears. Six subjects were implanted with a 31-mm MED-EL FLEX(SOFT) electrode, and two with a 24-mm medium (M) electrode, with insertion angles of the most apical contacts ranging from 565° to 758°. In the first experiment, frequency-place functions were derived from pure-tone matches to 1500-pps unmodulated pulse trains presented to individual electrodes and compared to Greenwood's frequency position map along the organ of Corti. While the overall median downward shift of the obtained frequency-place functions (-0.16 octaves re. Greenwood) and the mean shifts in the basal (<240°; -0.33 octaves) and middle (-0.35 octaves) regions were statistically significant, the shift in the apical region (>480°; 0.26 octaves) was not. Standard deviations of frequency-place functions were approximately half an octave at electrode insertion angles below 480°, increasing to an octave at higher angular locations while individual functions were gradually leveling off. In a second experiment, subjects matched the rates of unmodulated pulse trains presented to individual electrodes in the apical half of the array to low-frequency pure tones between 100 Hz and 450 Hz. The aim was to investigate the influence of electrode place on the salience of temporal pitch cues, for coding strategies that present temporal fine structure information via rate modulations on select apical channels. Most subjects achieved reliable matches to tone frequencies from 100 Hz to 300 Hz only on electrodes at angular insertion depths beyond 360°, while rate-matches to 450-Hz tones were primarily achieved on electrodes at shallower insertion angles. Only for electrodes in the second turn the average slopes of rate-pitch functions did not differ significantly from the pure-tone references, suggesting their use for the encoding of within-channel fine frequency information via rate modulations in temporal fine structure stimulation strategies. Copyright © 2013 Elsevier B.V. All rights reserved.

Vapor-Redissolution Technique for Reduction of POLYMER/Si Arrayed Waveguide Grating Loss

NASA Astrophysics Data System (ADS)

Zhang, Haiming; Zhang, Daming; Qin, Zhenkun; Ma, Chunsheng

An efficient vapor-redissolution technique is used to greatly reduce sidewall scattering loss in the polymer arrayed waveguide grating (AWG) fabricated on a silicon substrate. Smoother sidewalls are achieved and verified by scanning electron microscopy. Reduction of sidewall scattering loss is further measured for the loss measurement of both straight waveguides and AWG devices. The sidewall loss in straight polymer waveguide is decreased by 2.1 dB/cm, the insertion loss of our AWG device is reduced by about 5.5 dB for the central channel and 6.7 dB for the edge channels, the crosstalk is reduced by 2.5 dB, and 3-dB bandwidth is narrowed by 0.05 nm after the vapor-redissoluton treatment.

Real Time Sensing and Discrimination of Single Chemicals Using Channel of Phi29 DNA Packaging Nanomotor

PubMed Central

Haque, Farzin; Lunn, Jennifer; Fang, Huaming; Smithrud, David; Guo, Peixuan

2012-01-01

A highly sensitive and reliable method to sense and identify a single chemical at extremely low concentrations and high contamination is important for environmental surveillance, homeland security, athlete drug monitoring, toxin/drug screening, and earlier disease diagnosis. This manuscript reports a method for precise detection of single chemicals. The hub of the bacteriophage phi29 DNA packaging motor is a connector consisting of twelve protein subunits encircled into a 3.6-nm channel as a path for dsDNA to enter during packaging and to exit during infection. The connector has previously been inserted into a lipid bilayer to serve as a membrane-embedded channel. Herein we report the modification of the phi29 channel to develop a class of sensors to detect single chemicals. The Lysine-234 of each protein subunit was mutated to cysteine, generating 12-SH ring lining the channel wall. Chemicals passing through this robust channel and interactions with the SH-group generated extremely reliable, precise, and sensitive current signatures as revealed by single channel conductance assays. Ethane (57 Daltons), thymine (167 Daltons), and benzene (105 Daltons) with reactive thioester moieties were clearly discriminated upon interaction with the available set of cysteine residues. The covalent attachment of each analyte induced discrete step-wise blockage in current signature with a corresponding decrease in conductance due to the physical blocking of the channel. Transient binding of the chemicals also produced characteristic fingerprints that were deduced from the unique blockage amplitude and pattern of the signals. This study shows that the phi29 connector can be used to sense chemicals with reactive thioesters or maleimide using single channel conduction assays based on their distinct fingerprints. The results demonstrated that this channel system could be further developed into very sensitive sensing devices. PMID:22458779

Real-time sensing and discrimination of single chemicals using the channel of phi29 DNA packaging nanomotor.

PubMed

Haque, Farzin; Lunn, Jennifer; Fang, Huaming; Smithrud, David; Guo, Peixuan

2012-04-24

A highly sensitive and reliable method to sense and identify a single chemical at extremely low concentrations and high contamination is important for environmental surveillance, homeland security, athlete drug monitoring, toxin/drug screening, and earlier disease diagnosis. This article reports a method for precise detection of single chemicals. The hub of the bacteriophage phi29 DNA packaging motor is a connector consisting of 12 protein subunits encircled into a 3.6 nm channel as a path for dsDNA to enter during packaging and to exit during infection. The connector has previously been inserted into a lipid bilayer to serve as a membrane-embedded channel. Herein we report the modification of the phi29 channel to develop a class of sensors to detect single chemicals. The lysine-234 of each protein subunit was mutated to cysteine, generating 12-SH ring lining the channel wall. Chemicals passing through this robust channel and interactions with the SH group generated extremely reliable, precise, and sensitive current signatures as revealed by single channel conductance assays. Ethane (57 Da), thymine (167 Da), and benzene (105 Da) with reactive thioester moieties were clearly discriminated upon interaction with the available set of cysteine residues. The covalent attachment of each analyte induced discrete stepwise blockage in current signature with a corresponding decrease in conductance due to the physical blocking of the channel. Transient binding of the chemicals also produced characteristic fingerprints that were deduced from the unique blockage amplitude and pattern of the signals. This study shows that the phi29 connector can be used to sense chemicals with reactive thioesters or maleimide using single channel conduction assays based on their distinct fingerprints. The results demonstrated that this channel system could be further developed into very sensitive sensing devices.

Tagging of Endogenous BK Channels with a Fluorogen-Activating Peptide Reveals β4-Mediated Control of Channel Clustering in Cerebellum

PubMed Central

Pratt, Christopher P.; Kuljis, Dika A.; Homanics, Gregg E.; He, Jianjun; Kolodieznyi, Dmytro; Dudem, Srikanth; Hollywood, Mark A.; Barth, Alison L.; Bruchez, Marcel P.

2017-01-01

BK channels are critical regulators of neuronal activity, controlling firing, neurotransmitter release, cerebellar function, and BK channel mutations have been linked to seizure disorders. Modulation of BK channel gating is well characterized, regulated by accessory subunit interactions, intracellular signaling pathways, and membrane potential. In contrast, the role of intracellular trafficking mechanisms in controlling BK channel function, especially in live cells, has been less studied. Fluorogen-activating peptides (FAPs) are well-suited for trafficking and physiological studies due to the binding of malachite green (MG)-based dyes with sub-nanomolar affinity to the FAP, resulting in bright, photostable, far-red fluorescence. Cell-excluded MG dyes enable the selective tagging of surface protein and tracking through endocytic pathways. We used CRISPR to insert the FAP at the extracellular N-terminus of BKα in the first exon of its native locus, enabling regulation by the native promoter elements and tag incorporation into multiple splice isoforms. Motor coordination was found to be normal; however, BK channel expression seems to be reduced in some locations. Alternate start site selection or post-translational proteolytic processing resulted in incomplete FAP tagging of the BKα proteins in brain tissues. In Purkinje cell somata, FAP revealed BK channel clustering previously only observed by electron microscopy. Measurement of these clusters in β4+/- and β4-/- mice showed that puncta number and cluster fluorescence intensity on the soma are reduced in β4-/- knockout animals. This novel mouse line provides a versatile fluorescent platform for studying endogenous BK channels in living and fixed tissues. Future studies could apply this line to ex vivo neuronal cultures to study live-cell channel trafficking. PMID:29163049

The total position-spread tensor: Spin partition

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

El Khatib, Muammar, E-mail: elkhatib@irsamc.ups-tlse.fr; Evangelisti, Stefano, E-mail: stefano@irsamc.ups-tlse.fr; Leininger, Thierry, E-mail: Thierry.Leininger@irsamc.ups-tlse.fr

2015-03-07

The Total Position Spread (TPS) tensor, defined as the second moment cumulant of the position operator, is a key quantity to describe the mobility of electrons in a molecule or an extended system. In the present investigation, the partition of the TPS tensor according to spin variables is derived and discussed. It is shown that, while the spin-summed TPS gives information on charge mobility, the spin-partitioned TPS tensor becomes a powerful tool that provides information about spin fluctuations. The case of the hydrogen molecule is treated, both analytically, by using a 1s Slater-type orbital, and numerically, at Full Configuration Interactionmore » (FCI) level with a V6Z basis set. It is found that, for very large inter-nuclear distances, the partitioned tensor growths quadratically with the distance in some of the low-lying electronic states. This fact is related to the presence of entanglement in the wave function. Non-dimerized open chains described by a model Hubbard Hamiltonian and linear hydrogen chains H{sub n} (n ≥ 2), composed of equally spaced atoms, are also studied at FCI level. The hydrogen systems show the presence of marked maxima for the spin-summed TPS (corresponding to a high charge mobility) when the inter-nuclear distance is about 2 bohrs. This fact can be associated to the presence of a Mott transition occurring in this region. The spin-partitioned TPS tensor, on the other hand, has a quadratical growth at long distances, a fact that corresponds to the high spin mobility in a magnetic system.« less

Novel method for comparing coverage by future methods of ballistic facial protection.

PubMed

Breeze, J; Allanson-Bailey, L C; Hepper, A E; Lewis, E A

2015-01-01

The wearing of eye protection by United Kingdom soldiers in Afghanistan has reduced the morbidity caused by explosive fragments. However, the remaining face remains uncovered because there is a lack of evidence to substantiate the procurement of methods to protect it. Using a new computerised tool we entered details of the entry sites of surface wounds caused by explosive fragments in all UK soldiers who were injured in the face between 1 January 2010 and 31 December 2011. We compared clinical and predicted immediate and long term outcomes (as defined by the Abbreviated Injury Score (AIS) and the Functional Capacity Index (pFCI), respectively). We also used the tool to predict how additional protection in the form of a visor and mandible guard would affect outcomes. A soldier wearing eye protection was 9 times (1.03/0.12) less likely to sustain an eye injury than one without. However, 38% of soldiers in this series were not wearing eye protection at the time of injury. There was no significant difference between the AIS and pFCI scores predicted by the tool and those found clinically. There is limited evidence to support the use of a mandible guard; its greatest asset is better protection of the nose, but a visor would be expected to reduce long-term morbidity more than eye protection alone, and we recommend future trials to assess its acceptability to users. We think that use of this novel tool can help in the selection of future methods of ballistic facial protection. Copyright © 2014. Published by Elsevier Ltd.

Evaluation of a flexible bronchoscope prototype designed for bronchoscopy during mechanical ventilation: a proof-of-concept study.

PubMed

Nay, M-A; Auvet, A; Mankikian, J; Herve, V; Dequin, P-F; Guillon, A

2017-06-01

Bronchoscopy during mechanical ventilation of patients' lungs significantly affects ventilation because of partial obstruction of the tracheal tube, and may thus be omitted in the most severely ill patients. It has not previously been possible to reduce the external diameter of the bronchoscope without reducing the diameter of the suction channel, thus reducing the suctioning capacity of the device. We believed that a better-designed bronchoscope could improve the safety of bronchoscopy in patients whose lungs were ventilated. We designed a flexible bronchoscope prototype with a drumstick-shaped head consisting of a long, thin proximal portion; a short and large distal portion for camera docking; and a large suction channel throughout the length of the device. The aims of our study were to test the impact of our prototype on mechanical ventilation when inserted into the tracheal tube, and to assess suctioning capacity. We first tested the efficiency of the suction channel, and demonstrated that the suction flow of the prototype was similar to that of conventional adult bronchoscopes. We next evaluated the consequences of bronchoscopy when using the prototype on minute ventilation and intrathoracic pressures during mechanical ventilation: firstly, in vitro using a breathing simulator; and secondly, in vivo using a porcine model of pulmonary ventilation. The insertion of adult bronchoscopes into the tracheal tube immediately impaired the protective ventilation strategy employed, whereas the prototype preserved it. For the first time, we have developed an innovative flexible bronchoscope designed for bronchoscopy during invasive mechanical ventilation, that both preserved the protective ventilation strategy, and enabled efficient suction flow. © 2017 The Association of Anaesthetists of Great Britain and Ireland.

Wavelength-tunable filter utilizing non-cyclic arrayed waveguide grating to create colorless, directionless, contentionless ROADMs

NASA Astrophysics Data System (ADS)

Niwa, Masaki; Takashina, Shoichi; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-ichi; Watanabe, Toshio

2015-01-01

With the continuous increase in Internet traffic, reconfigurable optical add-drop multiplexers (ROADMs) have been widely adopted in the core and metro core networks. Current ROADMs, however, allow only static operation. To realize future dynamic optical-network services, and to minimize any human intervention in network operation, the optical signal add/drop part should have colorless/directionless/contentionless (C/D/C) capabilities. This is possible with matrix switches or a combination of splitter-switches and optical tunable filters. The scale of the matrix switch increases with the square of the number of supported channels, and hence, the matrix-switch-based architecture is not suitable for creating future large-scale ROADMs. In contrast, the numbers of splitter ports, switches, and tunable filters increase linearly with the number of supported channels, and hence the tunable-filter-based architecture will support all future traffic. So far, we have succeeded in fabricating a compact tunable filter that consists of multi-stage cyclic arrayed-waveguide gratings (AWGs) and switches by using planar-lightwave-circuit (PLC) technologies. However, this multistage configuration suffers from large insertion loss and filter narrowing. Moreover, power-consuming temperature control is necessary since it is difficult to make cyclic AWGs athermal. We propose here novel tunable-filter architecture that sandwiches a single-stage non-cyclic athermal AWG having flatter-topped passbands between small-scale switches. With this configuration, the optical tunable filter attains low insertion loss, large passband bandwidths, low power consumption, compactness, and high cost-effectiveness. A prototype is monolithically fabricated with PLC technologies and its excellent performance is experimentally confirmed utilizing 80-channel 30-GBaud dual-polarization quadrature phase-shift-keying (QPSK) signals.

Analyzing the components of the free-energy landscape in a calcium selective ion channel by Widom's particle insertion method

NASA Astrophysics Data System (ADS)

Boda, Dezső; Giri, Janhavi; Henderson, Douglas; Eisenberg, Bob; Gillespie, Dirk

2011-02-01

The selectivity filter of the L-type calcium channel works as a Ca2 + binding site with a very large affinity for Ca2 + versus Na+. Ca2 + replaces half of the Na+ ions in the filter even when these ions are present in 1 μM and 30 mM concentrations in the bath, respectively. The energetics of this strong selectivity is analyzed in this paper. We use Widom's particle insertion method to compute the space-dependent profiles of excess chemical potential in our grand canonical Monte Carlo simulations. These profiles define the free-energy landscape for the various ions. Following Gillespie [Biophys. J. 94, 1169 (2008)], the difference of the excess chemical potentials for the two competing ions defines the advantage that one of the ions has over the other in the competition for space in the crowded selectivity filter. These advantages depend on ionic bath concentrations: the ion that is present in the bath in larger quantity (Na+) has the "number" advantage which is balanced by the free-energy advantage of the other ion (Ca2 +). The excess chemical potentials are decomposed into hard sphere exclusion and electrostatic components. The electrostatic terms correspond to interactions with the mean electric field produced by ions and induced charges as well to ionic correlations beyond the mean field description. Dielectrics are needed to produce micromolar Ca2 + versus Na+ selectivity in the L-type channel. We study the behavior of these terms with changes in bath concentrations of ions, charges, and diameters of ions, as well as geometrical parameters such as radius of the pore and the dielectric constant of the protein. Ion selectivity in calcium binding proteins probably has a similar mechanism.

Direct quantification of transendothelial electrical resistance in organs-on-chips.

PubMed

van der Helm, Marinke W; Odijk, Mathieu; Frimat, Jean-Philippe; van der Meer, Andries D; Eijkel, Jan C T; van den Berg, Albert; Segerink, Loes I

2016-11-15

Measuring transendothelial or transepithelial electrical resistance (TEER) is a widely used method to monitor cellular barrier tightness in organs-on-chips. Unfortunately, integrated electrodes close to the cellular barrier hamper visual inspection of the cells or require specialized cleanroom processes to fabricate see-through electrodes. Out-of-view electrodes inserted into the chip's outlets are influenced by the fluid-filled microchannels with relatively high resistance. In this case, small changes in temperature or medium composition strongly affect the apparent TEER. To solve this, we propose a simple and universally applicable method to directly determine the TEER in microfluidic organs-on-chips without the need for integrated electrodes close to the cellular barrier. Using four electrodes inserted into two channels - two on each side of the porous membrane - and six different measurement configurations we can directly derive the isolated TEER independent of channel properties. We show that this method removes large variation of non-biological origin in chips filled with culture medium. Furthermore, we demonstrate the use of our method by quantifying the TEER of a monolayer of human hCMEC/D3 cerebral endothelial cells, mimicking the blood-brain barrier inside our microfluidic organ-on-chip device. We found stable TEER values of 22 Ω cm(2)±1.3 Ω cm(2) (average ± standard error of the mean of 4 chips), comparable to other TEER values reported for hCMEC/D3 cells in well-established Transwell systems. In conclusion, we demonstrate a simple and robust way to directly determine TEER that is applicable to any organ-on-chip device with two channels separated by a membrane. This enables stable and easily applicable TEER measurements without the need for specialized cleanroom processes and with visibility on the measured cell layer. Copyright © 2016 Elsevier B.V. All rights reserved.

Modulation of epithelial sodium channel trafficking and function by sodium 4-phenylbutyrate in human nasal epithelial cells.

PubMed

Prulière-Escabasse, Virginie; Planès, Carole; Escudier, Estelle; Fanen, Pascale; Coste, André; Clerici, Christine

2007-11-23

Sodium 4-phenylbutyrate (4-PBA) has been shown to correct the cellular trafficking of several mutant or nonmutant plasma membrane proteins such as cystic fibrosis transmembrane conductance regulator through the expression of 70-kDa heat shock proteins. The objective of the study was to determine whether 4-PBA may influence the functional expression of epithelial sodium channels (ENaC) in human nasal epithelial cells (HNEC). Using primary cultures of HNEC, we demonstrate that 4-PBA (5 mm for 6 h) markedly stimulated amiloride-sensitive sodium channel activity and that this was related to an increased abundance of alpha-, beta-, and gamma-ENaC subunits in the apical membrane. The increase in ENaC cell surface expression (i) was due to insertion of newly ENaC subunits as determined by brefeldin A experiments and (ii) was not associated with cell surface retention of ENaC subunits because endocytosis of ENaC subunits was unchanged. In addition, we find that ENaC co-immunoprecipitated with the heat shock protein constitutively expressed Hsc70, that has been reported to modulate ENaC trafficking, and that 4-PBA decreased Hsc70 protein level. Finally, we report that in cystic fibrosis HNEC obtained from two cystic fibrosis patients, 4-PBA increased functional expression of ENaC as demonstrated by the increase in amiloride-sensitive sodium transport and in alpha-, beta-, and gamma-ENaC subunit expression in the apical membrane. Our results suggest that in HNEC, 4-PBA increases the functional expression of ENaC through the insertion of new alpha-, beta-, and gamma-ENaC subunits into the apical membrane and also suggest that 4-PBA could modify ENaC trafficking by reducing Hsc70 protein expression.

Analyzing the components of the free-energy landscape in a calcium selective ion channel by Widom's particle insertion method.

PubMed

Boda, Dezso; Giri, Janhavi; Henderson, Douglas; Eisenberg, Bob; Gillespie, Dirk

2011-02-07

The selectivity filter of the L-type calcium channel works as a Ca(2+) binding site with a very large affinity for Ca(2+) versus Na(+). Ca(2+) replaces half of the Na(+) ions in the filter even when these ions are present in 1 μM and 30 mM concentrations in the bath, respectively. The energetics of this strong selectivity is analyzed in this paper. We use Widom's particle insertion method to compute the space-dependent profiles of excess chemical potential in our grand canonical Monte Carlo simulations. These profiles define the free-energy landscape for the various ions. Following Gillespie [Biophys. J. 94, 1169 (2008)], the difference of the excess chemical potentials for the two competing ions defines the advantage that one of the ions has over the other in the competition for space in the crowded selectivity filter. These advantages depend on ionic bath concentrations: the ion that is present in the bath in larger quantity (Na(+)) has the "number" advantage which is balanced by the free-energy advantage of the other ion (Ca(2+)). The excess chemical potentials are decomposed into hard sphere exclusion and electrostatic components. The electrostatic terms correspond to interactions with the mean electric field produced by ions and induced charges as well to ionic correlations beyond the mean field description. Dielectrics are needed to produce micromolar Ca(2+) versus Na(+) selectivity in the L-type channel. We study the behavior of these terms with changes in bath concentrations of ions, charges, and diameters of ions, as well as geometrical parameters such as radius of the pore and the dielectric constant of the protein. Ion selectivity in calcium binding proteins probably has a similar mechanism.

Quantum hacking on a practical continuous-variable quantum cryptosystem by inserting an external light

NASA Astrophysics Data System (ADS)

Qin, Hao; Kumar, Rupesh; Alleaume, Romain

2015-10-01

We report here a new side channel attack on a practical continuous-variable (CV) quantum key distribution (QKD) system. Inspired by blinding attack in discrete-variable QKD, we formalize an attack strategy by inserting an external light into a CV QKD system implemented Gaussian-modulated coherent state protocol and show that our attack can compromise its practical security. In this attack, we concern imperfections of a balanced homodyne detector used in CV QKD. According to our analysis, if one inserts an external light into Bob's signal port, due to the imperfect subtraction from the homodyne detector, the leakage of the external light contributes a displacement on the homodyne signal which causes detector electronics saturation. In consequence, Bob's quadrature measurement is not linear with the quadrature sent by Alice. By considering such vulnerability, a potential Eve can launch a full intercept-resend attack meanwhile she inserts an external light into Bob's signal port. By selecting proper properties of the external light, Eve actively controls the induced displacement value from the inserted light which results saturation of homodyne detection. In consequence, Eve can bias the excess noise due to the intercept-resend attack and the external light, such that Alice and Bob believe their excess noise estimation is below the null key threshold and they can still share a secret key. Our attack shows that the detector loopholes also exist in CV QKD, and it seems influence all the CV QKD systems using homodyne detection, since all the practical detectors have finite detection range.

Transmembrane helices containing a charged arginine are thermodynamically stable.

PubMed

Ulmschneider, Martin B; Ulmschneider, Jakob P; Freites, J Alfredo; von Heijne, Gunnar; Tobias, Douglas J; White, Stephen H

2017-10-01

Hydrophobic amino acids are abundant in transmembrane (TM) helices of membrane proteins. Charged residues are sparse, apparently due to the unfavorable energetic cost of partitioning charges into nonpolar phases. Nevertheless, conserved arginine residues within TM helices regulate vital functions, such as ion channel voltage gating and integrin receptor inactivation. The energetic cost of arginine in various positions along hydrophobic helices has been controversial. Potential of mean force (PMF) calculations from atomistic molecular dynamics simulations predict very large energetic penalties, while in vitro experiments with Sec61 translocons indicate much smaller penalties, even for arginine in the center of hydrophobic TM helices. Resolution of this conflict has proved difficult, because the in vitro assay utilizes the complex Sec61 translocon, while the PMF calculations rely on the choice of simulation system and reaction coordinate. Here we present the results of computational and experimental studies that permit direct comparison with the Sec61 translocon results. We find that the Sec61 translocon mediates less efficient membrane insertion of Arg-containing TM helices compared with our computational and experimental bilayer-insertion results. In the simulations, a combination of arginine snorkeling, bilayer deformation, and peptide tilting is sufficient to lower the penalty of Arg insertion to an extent such that a hydrophobic TM helix with a central Arg residue readily inserts into a model membrane. Less favorable insertion by the translocon may be due to the decreased fluidity of the endoplasmic reticulum (ER) membrane compared with pure palmitoyloleoyl-phosphocholine (POPC). Nevertheless, our results provide an explanation for the differences between PMF- and experiment-based penalties for Arg burial.

pH-dependent pore-forming activity of OmpATb from Mycobacterium tuberculosis and characterization of the channel by peptidic dissection.

PubMed

Molle, Virginie; Saint, Nathalie; Campagna, Sylvie; Kremer, Laurent; Lea, Edward; Draper, Philip; Molle, Gérard

2006-08-01

Mycobacteria are characterized by an unusual cell wall that controls nutrient and small hydrophilic compound permeability. Porin-like proteins are necessary to ensure the transport of molecules into the cell. Here, we investigated the pore-forming properties of OmpATb, a porin from Mycobacterium tuberculosis, in lipid bilayers. Multi-channel experiments showed an asymmetric behaviour with channel closures at negative critical voltages (Vc) and a strong decrease in Vc at acidic pH. Single-channel experiments gave conductance values of about 850 +/- 80 pS in 1 M KCl and displayed a weak cationic selectivity in 4-8 pH range. The production and characterization of a series of truncated OmpATb proteins, showed that the central domain (OmpATb73-220) was sufficient to induce the ion channel properties of the native protein in lipid bilayers, i.e. asymmetric insertion, pH-dependent voltage closure, cationic selectivity and similar conductance values in 1 M KCl. Western blot analysis suggests that the presence of OmpATb is only restricted to certain pathogenic species. Therefore, the propensity of channels of native OmpATb to close at low pH may represent an intrinsic property allowing pathogenic mycobacteria to adapt and survive to mildly acidic conditions, such as those encountered within the macrophage phagosome.

CLAG3 Self-Associates in Malaria Parasites and Quantitatively Determines Nutrient Uptake Channels at the Host Membrane.

PubMed

Gupta, Ankit; Balabaskaran-Nina, Praveen; Nguitragool, Wang; Saggu, Gagandeep S; Schureck, Marc A; Desai, Sanjay A

2018-05-08

Malaria parasites increase host erythrocyte permeability to ions and nutrients via a broad-selectivity channel known as the plasmodial surface anion channel (PSAC), linked to parasite-encoded CLAG3 and two associated proteins. These proteins lack the multiple transmembrane domains typically present in channel-forming proteins, raising doubts about their precise roles. Using the virulent human Plasmodium falciparum parasite, we report that CLAG3 undergoes self-association and that this protein's expression determines channel phenotype quantitatively. We overcame epigenetic silencing of clag3 paralogs and engineered parasites that express two CLAG3 isoforms simultaneously. Stoichiometric expression of these isoforms yielded intermediate channel phenotypes, in agreement with observed trafficking of both proteins to the host membrane. Coimmunoprecipitation and surface labeling revealed formation of CLAG3 oligomers. In vitro selections applied to these transfectant lines yielded distinct mutants with correlated changes in channel activity. These findings support involvement of the identified oligomers in PSAC formation and parasite nutrient acquisition. IMPORTANCE Malaria parasites are globally important pathogens that evade host immunity by replicating within circulating erythrocytes. To facilitate intracellular growth, these parasites increase erythrocyte nutrient uptake through an unusual ion channel. The parasite CLAG3 protein is a key determinant of this channel, but its lack of homology to known ion channels has raised questions about possible mechanisms. Using a new method that allows simultaneous expression of two different CLAG3 proteins, we identify self-association of CLAG3. The two expressed isoforms faithfully traffic to and insert in the host membrane, while remaining associated with two unrelated parasite proteins. Both the channel phenotypes and molecular changes produced upon selections with a highly specific channel inhibitor are consistent with a multiprotein complex that forms the nutrient pore. These studies support direct involvement of the CLAG3 protein in channel formation and are relevant to antimalarial drug discovery projects targeting parasite nutrient acquisition.

Ion channels for mechanotransduction in the crayfish stretch receptor.

PubMed

Rydqvist, Bo

2007-01-01

Mechanosensitivity is found in almost every cell in all organisms from bacteria to vertebrates and covers a wide spectrum of function from osmosensing to mechanical sensing in the specialized receptors, such as the hair cells of the cochlea. The molecular substrate for such mechanosensitivity is thought to be mechanosensitive ion channels (MSCs). Because most development regarding the molecular aspects of the MSC has been made in nonsensory or sensory systems, which have not been accessible to recordings from ion channels, it is important to focus on the mechanosensitivity of sensory organs where their functional importance is undisputed. The stretch receptor organ (SRO) of the crustaceans is a suitable preparation for such studies. Each organ contains two receptors: one slowly and one rapidly adapting receptor neurons. The primary mechanosensitivity is generated by two types of MSC of hitherto unknown molecular type located in the neuronal dendrites, which are inserted into a receptor muscle fiber. In addition to the MSCs, the neurons contain voltage-gated Na(+) channels, which seem to be differently located in the slowly and rapidly adapting neurons. At least three types of voltage-gated K(+) channels are present in the sensory neurons, the location of which is not known. The spatial distribution of ion channels and the kinetics of the channels, together with the viscoelastic properties of the receptor muscles, determine the overall transducer properties and impulse firing of the two receptor neurons, including their typical adaptive characteristics. © 2007, Elsevier Inc. All right reserved.

MHD work related to a self-cooled Pb-17Li blanket with poloidal-radial-toroidal ducts

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

Reimann, J.; Barleon, L.; Buehler, L.

1994-12-31

For self cooled liquid metal blankets MHD pressure drop and velocity distributions are considered as critical issues. This paper summarizes MHD work performed for a DEMO-relevant Pb-17Li blanket which uses essential characteristics of a previous ANL design: The coolant flows downwards in the rear poloidal ducts, turns by 180{degrees} at the blanket bottom and is distributed from the ascending poloidal ducts into short radial channels which feed the toroidal First Wall coolant ducts (aligned with the main magnetic field direction). The flow through the subsequent radial channels is collected again in poloidal channels and the coolant leaves the blanket segmentmore » at the top. The blanket design is based on the use of flow channel inserts (FCIs) (which means electrically thin conducting walls for MHD) for all ducts except for the toroidal FW coolant channels. MHD related issues were defined and estimations of corresponding pressure drops were performed. Previous experimental work included a proof of principle of FCIs and a detailed experiment with a single {open_quotes}poloidal{sm_bullet}toroidal{sm_bullet}poloidal{close_quotes} duct (cooperation with ANL). In parallel, a numerical code based on the Core Flow Approximation (CFA) was developed to predict pressure drop and velocity distributions for arbitrary single duct geometries.« less

Investigation of Ion Channel Activities of Gramicidin A in the Presence of Ionic Liquids Using Model Cell Membranes

PubMed Central

Ryu, Hyunil; Lee, Hwankyu; Iwata, Seigo; Choi, Sangbaek; Ki Kim, Moon; Kim, Young-Rok; Maruta, Shinsaku; Min Kim, Sun; Jeon, Tae-Joon

2015-01-01

Ionic liquids (ILs) are considered to be green solvents because of their non-volatility. Although ILs are relatively safe in the atmospheric environment, they may be toxic in other environments. Our previous research showed that the cytotoxicity of ILs to biological organisms is attributable to interference with cell membranes by IL insertion. However, the effects of ILs on ion channels, which play important roles in cell homeostasis, have not been comprehensively studied to date. In this work, we studied the interactions between ILs and lipid bilayer membranes with gramicidin A ion channels. We used two methods, namely electrical and fluorescence measurements of ions that permeate the membrane. The lifetimes of channels were increased by all the ILs tested in this work via stabilizing the compressed structure of the lipid bilayer and the rate of ion flux through gA channels was decreased by changing the membrane surface charge. The former effect, which increased the rate of ion flux, was dominant at high salt concentrations, whereas the latter, which decreased the rate of ion flux, was dominant at low salt concentrations. The effects of ILs increased with increasing concentration and alkyl chain length. The experimental results were further studied using molecular dynamics simulations. PMID:26189604

Defined lipid analogues induce transient channels to facilitate drug-membrane traversal and circumvent cancer therapy resistance

PubMed Central

van Hell, Albert J.; Melo, Manuel N.; van Blitterswijk, Wim J.; Gueth, Dayana M.; Braumuller, Tanya M.; Pedrosa, Lilia R. C.; Song, Ji-Ying; Marrink, Siewert J.; Koning, Gerben A.; Jonkers, Jos; Verheij, Marcel

2013-01-01

Design and efficacy of bioactive drugs is restricted by their (in)ability to traverse cellular membranes. Therapy resistance, a major cause of ineffective cancer treatment, is frequently due to suboptimal intracellular accumulation of the drug. We report a molecular mechanism that promotes trans-membrane movement of a stereotypical, widely used anti-cancer agent to counteract resistance. Well-defined lipid analogues adapt to the amphiphilic drug doxorubicin, when co-inserted into the cell membrane, and assemble a transient channel that rapidly facilitates the translocation of the drug onto the intracellular membrane leaflet. Molecular dynamic simulations unveiled the structure and dynamics of membrane channel assembly. We demonstrate that this principle successfully addresses multi-drug resistance of genetically engineered mouse breast cancer models. Our results illuminate the role of the plasma membrane in restricting the efficacy of established therapies and drug resistance - and provide a mechanism to overcome ineffectiveness of existing and candidate drugs. PMID:23739489

Structure of colicin I receptor bound to the R-domain of colicin Ia: implications for protein import

PubMed Central

Buchanan, Susan K; Lukacik, Petra; Grizot, Sylvestre; Ghirlando, Rodolfo; Ali, Maruf M U; Barnard, Travis J; Jakes, Karen S; Kienker, Paul K; Esser, Lothar

2007-01-01

Colicin Ia is a 69 kDa protein that kills susceptible Escherichia coli cells by binding to a specific receptor in the outer membrane, colicin I receptor (70 kDa), and subsequently translocating its channel forming domain across the periplasmic space, where it inserts into the inner membrane and forms a voltage-dependent ion channel. We determined crystal structures of colicin I receptor alone and in complex with the receptor binding domain of colicin Ia. The receptor undergoes large and unusual conformational changes upon colicin binding, opening at the cell surface and positioning the receptor binding domain of colicin Ia directly above it. We modelled the interaction with full-length colicin Ia to show that the channel forming domain is initially positioned 150 Å above the cell surface. Functional data using full-length colicin Ia show that colicin I receptor is necessary for cell surface binding, and suggest that the receptor participates in translocation of colicin Ia across the outer membrane. PMID:17464289

Thoracic pedicle classification determined by inner cortical width of pedicles on computed tomography images: its clinical significance for posterior vertebral column resection to treat rigid and severe spinal deformities-a retrospective review of cases.

PubMed

Zhang, Ying; Xie, Jingming; Wang, Yingsong; Bi, Ni; Zhao, Zhi; Li, Tao

2014-08-13

Posterior vertebral column resection (PVCR) is an effective alternative for treating rigid and severe spinal deformities. Accurate placement of pedicle screws, especially apically, is crucial. As morphologic evaluations of thoracic pedicles have not provided objective criteria, we propose a thoracic pedicle classification for treating rigid and severe spinal deformities. A consecutive series of 56 patients with severe and rigid spinal deformities who underwent PVCR at a single institution were reviewed retrospectively. Altogether, 1098 screws were inserted into thoracic pedicles at T2-T12. Based on the inner cortical width of the thoracic pedicles, the patients were divided into four groups: group 1 (0-1.0 mm), group 2 (1.1-2.0 mm), group 3 (2.1-3.0 mm), group 4 (≥3.1 mm). The proportion of screws accurately inserted in thoracic pedicles for each group was calculated. Statistical analysis was also performed regarding types of thoracic pedicles classified by Lenke et al. (SPINE 35:1836-1842, 2010) using a morphological method. There were statistically significant differences in the rates of screws inserted in thoracic pedicles between the groups (P < 0.008) except groups 3 and 4 (P > 0.008), which were then combined. The accuracies for the three new groups were 35.05%, 65.34%, and 88.32%, respectively, with statistically significant differences between the groups (P < 0.017). Rates of screws inserted in thoracic pedicles classified by Lenke et al. (SPINE 35:1836-1842, 2010) were 82.31%, 83.40%, 80.00%, and 30.28% for types A, B, C, and D, respectively. There was no statistically significant difference (P > 0.008) between these types except between type D and the other three types (P < 0.008). The inner cortical width of thoracic pedicles is the sole factor crucial for accurate placement of thoracic pedicle screws. We propose a computed tomography-based classification of the pedicle's inner cortical width: type I thoracic pedicle: absent channel, inner cortical width of 0-1 mm; type II: presence of a channel of which type IIa has an inner cortical width of 1.1-2.0 mm and type IIb a width of ≥2.1 mm. The proposed classification can help surgeons predict whether screws can be inserted into the thoracic pedicle, thus guiding instrumentation when PVCR is performed.

Dynamic redistribution of calcium sensitive potassium channels (hK(Ca)3.1) in migrating cells.

PubMed

Schwab, Albrecht; Nechyporuk-Zloy, Volodymyr; Gassner, Birgit; Schulz, Christoph; Kessler, Wolfram; Mally, Sabine; Römer, Michael; Stock, Christian

2012-02-01

Calcium-sensitive potassium channels (K(Ca)3.1) are expressed in virtually all migrating cells. Their activity is required for optimal cell migration so that their blockade leads to slowing down. K(Ca)3.1 channels must be inserted into the plasma membrane in order to elicit their physiological function. However, the plasma membrane of migrating cells is subject to rapid recycling by means of endo- and exocytosis. Here, we focussed on the endocytic internalization and the intracellular transport of the human isoform hK(Ca)3.1. A hK(Ca)3.1 channel construct with an HA-tag in the extracellularly located S3-S4 linker was transfected into migrating transformed renal epithelial MDCK-F cells. Channel internalization was visualized and quantified with immunofluorescence and a cell-based ELISA. Movement of hK(Ca)3.1 channel containing vesicles as well as migration of MDCK-F cells were monitored by means of time lapse video microscopy. hK(Ca)3.1 channels are endocytosed during migration. Most of the hK(Ca)3.1 channel containing vesicles are moving at a speed of up to 2 µm/sec in a microtubule-dependent manner towards the front of MDCK-F cells. Our experiments indicate that endocytosis of hK(Ca)3.1 channels is clathrin-dependent since they colocalize with clathrin adaptor proteins and since it is impaired when a C-terminal dileucine motif is mutated. The C-terminal dileucine motif is also important for the subcellular localization of hK(Ca)3.1 channels in migrating cells. Mutated channels are no longer concentrated at the leading edge. We therefore propose that recycling of hK(Ca)3.1 channels contributes to their characteristic subcellular distribution in migrating cells. Copyright © 2011 Wiley Periodicals, Inc.

Boundary Layer Transition Protuberance Tests at NASA JSC Arc-Jet Facility

NASA Technical Reports Server (NTRS)

Larin, M. E.; Marichalar, J. J.; Kinder, G. R.; Campbell, C. H.; Riccio, J. R.; Nquyen, T. Q.; DelPapa, S. V.; Pulsonetti, M. V.

2009-01-01

A series of arc-jet tests in support of the Shuttle Orbiter Boundary Layer Transition flight experiment was conducted in the Channel Nozzle of the NASA Johnson Space Center Atmospheric Reentry Materials and Structures Facility. The boundary layer trip was a protrusion of a certain height and geometry fabricated as part of a 6"x6" tile insert, a special test article made of the Boeing Rigid Insulation tile material and coated with the Reaction Cured Glass used for the bottom fuselage tiles of the Space Shuttle Orbiter. A total of five such tile inserts were manufactured: four with the 0.25-in. trip height, and one with the 0.35-in. trip height. The tile inserts were interchangeably installed in the center of the 24"x24" variable configuration tile array mounted in the 24"x24" test section of the channel nozzle. The objectives of the test series were to demonstrate that the boundary layer trip can safely withstand the Space Shuttle Orbiter flight-like re-entry environments and provide temperature data on the protrusion surface, surfaces of the nearby tiles upstream and downstream of the trip, as well as the bond line between the tiles and the structure. The targeted test environments were defined for the tip of the protrusion, away from the nominal surface of the tile array. The arc jet test conditions were approximated in order to produce the levels of the free stream total enthalpy at the protrusion height similar to those expected in flight. The test articles were instrumented with surface, sidewall and bond line thermocouples. Additionally, Tempilaq temperature-indicating paint was applied to the nominal tiles of the tile array in locations not interfering with the protrusion trip. Five different grades of paint were used that disintegrate at different temperatures between 1500 and 2000 deg F. The intent of using the paint was to gauge the RCG-coated tile surface temperature, as well as determine its usefulness for a flight experiment. This paper provides an overview of the channel nozzle arc jet, test articles and test conditions, as well as the results of the arc-jet tests including the measured temperature response of the test articles, their pre- and post-test surface scans, condition of the thermal paint, and continents on the protrusion tip heating achieved in tests compared to the computational fluid dynamics predictions.

Towards nonaxisymmetry; initial results using the Flux Coordinate Independent method in BOUT++

NASA Astrophysics Data System (ADS)

Shanahan, B. W.; Hill, P.; Dudson, B. D.

2016-11-01

Fluid simulation of stellarator edge transport is difficult due to the complexities of mesh generation; the stochastic edge and strong nonaxisymmetry inhibit the use of field aligned coordinate systems. The recent implementation of the Flux Coordinate Independent method for calculating parallel derivatives in BOUT++ has allowed for more complex geometries. Here we present initial results of nonaxisymmetric diffusion modelling as a step towards stellarator turbulence modelling. We then present initial (non-turbulent) transport modelling using the FCI method and compare the results with analytical calculations. The prospects for future stellarator transport and turbulence modelling are discussed.

The effect of constraint on fuel-coolant interactions in a confined geometry

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

Park, H.; Corradini, M.L.

A Fuel-Coolant Interaction (FCI or vapor explosion) is the phenomena in which a hot liquid rapidly transfers its internal energy into a surrounding colder and more volatile liquid. The energetics of such a complex multi-phase and multi-component phenomenon is partially determined by the surrounding boundary conditions. As one of the boundary conditions, we studied the effect of constraint on FCIs. The WFCI-D series of experiments were performed specifically to observe this effect. The results from these and our previous WFCI tests as well as those of other investigators are compared.

Enhanced MicroChannel Heat Transfer in Macro-Geometry using Conventional Fabrication Approach

NASA Astrophysics Data System (ADS)

Ooi, KT; Goh, AL

2016-09-01

This paper presents studies on passive, single-phase, enhanced microchannel heat transfer in conventionally sized geometry. The intention is to allow economical, simple and readily available conventional fabrication techniques to be used for fabricating macro-scale heat exchangers with microchannel heat transfer capability. A concentric annular gap between a 20 mm diameter channel and an 19.4 mm diameter insert forms a microchannel where heat transfer occurs. Results show that the heat transfer coefficient of more than 50 kW/m·K can be obtained for Re≈4,000, at hydraulic diameter of 0.6 mm. The pressure drop values of the system are kept below 3.3 bars. The present study re-confirms the feasibility of fabricating macro-heat exchangers with microchannel heat transfer capability.

Effects of turn region treatments on pressure loss through sharp 180-degree bends

NASA Astrophysics Data System (ADS)

Plevich, C. W.; Metzger, D. E.

An experimental study was conducted to evaluate the effect of geometric turn region inserts on pressure losses for flow through sharp 180-degree channel turns typical of internal cooling passages in gas turbine engine airfoils. The experiments were conducted in a rectangular cross-sectioned channel with 90-degree transverse rib roughening in both inlet and outlet legs, starting with completely smooth turn regions and progressing through various modifications including corner fillets, radial ribs, and turning vanes. The results show that modifications to the turn region geometry, particularly the inclusion of a single semi-circular turning vane, significantly reduce the pressure losses associated with coolant flows through sharp 180-degree turns and therefore can result in increased coolant flow for a given coolant supply pressure.

In vivo voltammetry: from wire to wireless measurements.

PubMed

Crespi, Francesco; Dalessandro, Davide; Annovazzi-Lodi, Valerio; Heidbreder, Christian; Norgia, Michele

2004-12-30

A novel telemetric system based on either differential pulse voltammetry (DPV) or direct current amperometry (DCA) by using a diffused infrared transmission channel is presented. Unlike similar pre-existing instruments based on infrared transmission, the present system works on a single-way communication, thus avoiding problems related to cross-talking between two-way channels. The infrared channel is also immune from electromagnetic interferences from the surrounding environment. Further advancement is the development of an original miniaturised system (dimension 1cm x 1.2 cm x 0.5 cm) with reduced weight (5-6 g), suitable for affixing to the rat head and allowing real time telemetric monitoring using DCA sampling of neurotransmitters such as dopamine or serotonin every 100 ms. The set-up is based on a transmitter (TX) circuit mounted on the animal's head and connected to the electrodes inserted into its brain. The TX circuit generates the proper electrical signals for DPV or DCA, collects the electrical response of the brain and transmits it, via an infrared channel, to a receiving station (RX) interfaced with a personal computer. The PC performs the sampling and elaboration of polarographic traces in a flexible and programmable way.

Mode division multiplexing using an orbital angular momentum mode sorter and MIMO-DSP over a graded-index few-mode optical fibre

PubMed Central

Huang, Hao; Milione, Giovanni; Lavery, Martin P. J.; Xie, Guodong; Ren, Yongxiong; Cao, Yinwen; Ahmed, Nisar; An Nguyen, Thien; Nolan, Daniel A.; Li, Ming-Jun; Tur, Moshe; Alfano, Robert R.; Willner, Alan E.

2015-01-01

Mode division multiplexing (MDM)– using a multimode optical fiber’s N spatial modes as data channels to transmit N independent data streams – has received interest as it can potentially increase optical fiber data transmission capacity N-times with respect to single mode optical fibers. Two challenges of MDM are (1) designing mode (de)multiplexers with high mode selectivity (2) designing mode (de)multiplexers without cascaded beam splitting’s 1/N insertion loss. One spatial mode basis that has received interest is that of orbital angular momentum (OAM) modes. In this paper, using a device referred to as an OAM mode sorter, we show that OAM modes can be (de)multiplexed over a multimode optical fiber with higher than −15 dB mode selectivity and without cascaded beam splitting’s 1/N insertion loss. As a proof of concept, the OAM modes of the LP11 mode group (OAM−1,0 and OAM+1,0), each carrying 20-Gbit/s polarization division multiplexed and quadrature phase shift keyed data streams, are transmitted 5km over a graded-index, few-mode optical fibre. Channel crosstalk is mitigated using 4 × 4 multiple-input-multiple-output digital-signal-processing with <1.5 dB power penalties at a bit-error-rate of 2 × 10−3. PMID:26450398

Mode division multiplexing using an orbital angular momentum mode sorter and MIMO-DSP over a graded-index few-mode optical fibre.

PubMed

Huang, Hao; Milione, Giovanni; Lavery, Martin P J; Xie, Guodong; Ren, Yongxiong; Cao, Yinwen; Ahmed, Nisar; An Nguyen, Thien; Nolan, Daniel A; Li, Ming-Jun; Tur, Moshe; Alfano, Robert R; Willner, Alan E

2015-10-09

Mode division multiplexing (MDM)- using a multimode optical fiber's N spatial modes as data channels to transmit N independent data streams - has received interest as it can potentially increase optical fiber data transmission capacity N-times with respect to single mode optical fibers. Two challenges of MDM are (1) designing mode (de)multiplexers with high mode selectivity (2) designing mode (de)multiplexers without cascaded beam splitting's 1/N insertion loss. One spatial mode basis that has received interest is that of orbital angular momentum (OAM) modes. In this paper, using a device referred to as an OAM mode sorter, we show that OAM modes can be (de)multiplexed over a multimode optical fiber with higher than -15 dB mode selectivity and without cascaded beam splitting's 1/N insertion loss. As a proof of concept, the OAM modes of the LP11 mode group (OAM-1,0 and OAM+1,0), each carrying 20-Gbit/s polarization division multiplexed and quadrature phase shift keyed data streams, are transmitted 5km over a graded-index, few-mode optical fibre. Channel crosstalk is mitigated using 4 × 4 multiple-input-multiple-output digital-signal-processing with <1.5 dB power penalties at a bit-error-rate of 2 × 10(-3).

Mode division multiplexing using an orbital angular momentum mode sorter and MIMO-DSP over a graded-index few-mode optical fibre

NASA Astrophysics Data System (ADS)

Huang, Hao; Milione, Giovanni; Lavery, Martin P. J.; Xie, Guodong; Ren, Yongxiong; Cao, Yinwen; Ahmed, Nisar; An Nguyen, Thien; Nolan, Daniel A.; Li, Ming-Jun; Tur, Moshe; Alfano, Robert R.; Willner, Alan E.

2015-10-01

Mode division multiplexing (MDM)- using a multimode optical fiber’s N spatial modes as data channels to transmit N independent data streams - has received interest as it can potentially increase optical fiber data transmission capacity N-times with respect to single mode optical fibers. Two challenges of MDM are (1) designing mode (de)multiplexers with high mode selectivity (2) designing mode (de)multiplexers without cascaded beam splitting’s 1/N insertion loss. One spatial mode basis that has received interest is that of orbital angular momentum (OAM) modes. In this paper, using a device referred to as an OAM mode sorter, we show that OAM modes can be (de)multiplexed over a multimode optical fiber with higher than -15 dB mode selectivity and without cascaded beam splitting’s 1/N insertion loss. As a proof of concept, the OAM modes of the LP11 mode group (OAM-1,0 and OAM+1,0), each carrying 20-Gbit/s polarization division multiplexed and quadrature phase shift keyed data streams, are transmitted 5km over a graded-index, few-mode optical fibre. Channel crosstalk is mitigated using 4 × 4 multiple-input-multiple-output digital-signal-processing with <1.5 dB power penalties at a bit-error-rate of 2 × 10-3.

NMR measurement system including two synchronized ring buffers, with 128 rf coils for in situ water monitoring in a polymer electrolyte fuel cell

NASA Astrophysics Data System (ADS)

Ogawa, Kuniyasu; Haishi, Tomoyuki; Aoki, Masaru; Hasegawa, Hiroshi; Morisaka, Shinichi; Hashimoto, Seitaro

2017-01-01

A small radio-frequency (rf) coil inserted into a polymer electrolyte fuel cell (PEFC) can be used to acquire nuclear magnetic resonance (NMR) signals from the water in a membrane electrode assembly (MEA) or in oxygen gas channels in the PEFC. Measuring the spatial distribution of the water in a large PEFC requires using many rf probes, so an NMR measurement system which acquires NMR signals from 128 rf probes at intervals of 0.5 s was manufactured. The system has eight rf transceiver units with a field-programmable gate array (FPGA) for modulation of the excitation pulse and quadrature phase detection of the NMR signal, and one control unit with two ring buffers for data control. The sequence data required for the NMR measurement were written into one ring buffer. The acquired NMR signal data were then written temporarily into the other ring buffer and then were transmitted to a personal computer (PC). A total of 98 rf probes were inserted into the PEFC that had an electrical generation area of 16 cm × 14 cm, and the water generated in the PEFC was measured when the PEFC operated at 100 A. As a result, time-dependent changes in the spatial distribution of the water content in the MEA and the water in the oxygen gas channels were obtained.

Dissipationless conductance in a topological coaxial cable

NASA Astrophysics Data System (ADS)

Schuster, Thomas; Iadecola, Thomas; Chamon, Claudio; Jackiw, Roman; Pi, So-Young

2016-09-01

We present a dynamical mechanism leading to dissipationless conductance, whose quantized value is controllable in a (3+1)-dimensional electronic system. The mechanism is exemplified by a theory of Weyl fermions coupled to a Higgs field, also known as an axion insulator. We show that the insertion of an axial gauge flux can induce vortex lines in the Higgs field, similar to the development of vortices in a superconductor upon the insertion of magnetic flux. We further show that the necessary axial gauge flux can be generated using Rashba spin-orbit coupling or a magnetic field. Vortex lines in the Higgs field are known to bind chiral fermionic modes, each of which serves as a one-way channel for electric charge with conductance e2/h . Combining these elements, we present a physical picture, the "topological coaxial cable," illustrating how the value of the quantized conductance could be controlled in such an axion insulator.

Switchable multiwavelength thulium-doped fiber ring lasers

NASA Astrophysics Data System (ADS)

Zhao, Shui; Lu, Ping; Liu, Deming; Zhang, Jiangshan

2013-08-01

Two kinds of thulium-doped fiber ring lasers based on a spatial mode beating filter and comb filtering effect are presented and experimentally demonstrated, which all show multiwavelength laser spectrum around 2 μm. In the implementation of the first type of experiment configuration by the use of a piece of multimode fiber (MMF) as a spatial mode beating filter, dual-,triple-, and quadruple-wavelengths appeared whose extinction noise ratio is 25 dB by adjusting the angle of polarization controller. Different wavelength spaces are obtained by inserting different lengths of MMF. The second type is achieved by inserting a Sagnac loop mirror, which was constructed by a 3-dB coupler and a piece of polarization maintaining fiber. Seven stable wavelengths with channel spacing of 0.65 nm and an extinction ratio of 35 dB was achieved. These systems are simple and easy to construct, which can be useful for 2 μm wavelength-division-multiplexed applications.

Prediction of neutral noble gas insertion compounds with heavier pnictides: FNgY (Ng = Kr and Xe; Y = As, Sb and Bi).

PubMed

Ghosh, Ayan; Manna, Debashree; Ghanty, Tapan K

2016-04-28

A novel class of interesting insertion compounds obtained through the insertion of a noble gas atom into the heavier pnictides have been explored by various ab initio quantum chemical techniques. Recently, the first neutral noble gas insertion compounds, FXeY (Y = P, N), were theoretically predicted to be stable; the triplet state was found to be the most stable state, with a high triplet-singlet energy gap, by our group. In this study, we investigated another noble gas inserted compound, FNgY (Ng = Kr and Xe; Y = As, Sb and Bi), with a triplet ground state. Density functional theory (DFT), second order Møller-Plesset perturbation theory (MP2), coupled-cluster theory (CCSD(T)) and multi-reference configuration interaction (MRCI) based techniques have been utilized to investigate the structures, stabilities, harmonic vibrational frequencies, charge distributions and topological properties of these compounds. These predicted species, FNgY (Ng = Kr and Xe; Y = As, Sb and Bi) are found to be energetically stable with respect to all the probable 2-body and 3-body dissociation pathways, except for the 2-body channel leading to the global minimum products (FY + Ng). Nevertheless, the finite barrier height corresponding to the saddle points of the compounds connected to their respective global minima products indicates that these compounds are kinetically stable. The structural parameters, energetics, and charge distribution results as well as atoms-in-molecules (AIM) analysis suggest that these predicted molecules can be best represented as F(-)[(3)NgY](+). Thus, all the aforementioned computed results clearly indicate that it may be possible to experimentally prepare the most stable triplet state of FNgY molecules under cryogenic conditions through a matrix isolation technique.

Biogenesis of the mitochondrial TOM complex: Mim1 promotes insertion and assembly of signal-anchored receptors.

PubMed

Becker, Thomas; Pfannschmidt, Sylvia; Guiard, Bernard; Stojanovski, Diana; Milenkovic, Dusanka; Kutik, Stephan; Pfanner, Nikolaus; Meisinger, Chris; Wiedemann, Nils

2008-01-04

The translocase of the outer membrane (TOM complex) is the central entry gate for nuclear-encoded mitochondrial precursor proteins. All Tom proteins are also encoded by nuclear genes and synthesized as precursors in the cytosol. The channel-forming beta-barrel protein Tom40 is targeted to mitochondria via Tom receptors and inserted into the outer membrane by the sorting and assembly machinery (SAM complex). A further outer membrane protein, Mim1, plays a less defined role in assembly of Tom40 into the TOM complex. The three receptors Tom20, Tom22, and Tom70 are anchored in the outer membrane by a single transmembrane alpha-helix, located at the N terminus in the case of Tom20 and Tom70 (signal-anchored) or in the C-terminal portion in the case of Tom22 (tail-anchored). Insertion of the precursor of Tom22 into the outer membrane requires pre-existing Tom receptors while the import pathway of the precursors of Tom20 and Tom70 is only poorly understood. We report that Mim1 is required for efficient membrane insertion and assembly of Tom20 and Tom70, but not Tom22. We show that Mim1 associates with SAM(core) components to a large SAM complex, explaining its role in late steps of the assembly pathway of Tom40. We conclude that Mim1 is not only required for biogenesis of the beta-barrel protein Tom40 but also for membrane insertion and assembly of signal-anchored Tom receptors. Thus, Mim1 plays an important role in the efficient assembly of the mitochondrial TOM complex.

A novel dihydropyridine with 3-aryl meta-hydroxyl substitution blocks L-type calcium channels in rat cardiomyocytes.

PubMed

Galvis-Pareja, David; Zapata-Torres, Gerald; Hidalgo, Jorge; Ayala, Pedro; Pedrozo, Zully; Ibarra, Cristián; Diaz-Araya, Guillermo; Hall, Andrew R; Vicencio, Jose Miguel; Nuñez-Vergara, Luis; Lavandero, Sergio

2014-08-15

Dihydropyridines are widely used for the treatment of several cardiac diseases due to their blocking activity on L-type Ca(2+) channels and their renowned antioxidant properties. We synthesized six novel dihydropyridine molecules and performed docking studies on the binding site of the L-type Ca(2+) channel. We used biochemical techniques on isolated adult rat cardiomyocytes to assess the efficacy of these molecules on their Ca(2+) channel-blocking activity and antioxidant properties. The Ca(2+) channel-blocking activity was evaluated by confocal microscopy on fluo-3AM loaded cardiomyocytes, as well as using patch clamp experiments. Antioxidant properties were evaluated by flow cytometry using the ROS sensitive dye 1,2,3 DHR. Our docking studies show that a novel compound with 3-OH substitution inserts into the active binding site of the L-type Ca(2+) channel previously described for nitrendipine. In biochemical assays, the novel meta-OH group in the aryl in C4 showed a high blocking effect on L-type Ca(2+) channel as opposed to para-substituted compounds. In the tests we performed, none of the molecules showed antioxidant properties. Only substitutions in C2, C3 and C5 of the aryl ring render dihydropyridine compounds with the capacity of blocking LTCC. Based on our docking studies, we postulate that the antioxidant activity requires a larger group than the meta-OH substitution in C2, C3 or C5 of the dihydropyridine ring. Copyright © 2014 Elsevier Inc. All rights reserved.

Channel Analysis for a 6.4 Gb s-1 DDR5 Data Buffer Receiver Front-End

NASA Astrophysics Data System (ADS)

Lehmann, Stefanie; Gerfers, Friedel

2017-09-01

In this contribution, the channel characteristic of the next generation DDR5-SDRAM architecture and possible approaches to overcome channel impairments are analysed. Because modern enterprise server applications and networks demand higher memory bandwidth, throughput and capacity, the DDR5-SDRAM specification is currently under development as a follow-up of DDR4-SDRAM technology. In this specification, the data rate is doubled to DDR5-6400 per IO as compared to the former DDR4-3200 architecture, resulting in a total per DIMM data rate of up to 409.6 Gb s-1. The single-ended multi-point-to-point CPU channel architecture in DDRX technology remains the same for DDR5 systems. At the specified target data rate, insertion loss, reflections, cross-talk as well as power supply noise become more severe and have to be considered. Using the data buffer receiver front-end of a load-reduced memory module, sophisticated equalisation techniques can be applied to ensure target BER at the increased data rate. In this work, the worst case CPU back-plane channel is analysed to derive requirements for receiver-side equalisation from the channel response characteristics. First, channel impairments such as inter-symbol-interference, reflections from the multi-point channel structure, and crosstalk from neighboring lines are analysed in detail. Based on these results, different correction methods for DDR5 data buffer front-ends are discussed. An architecture with 1-tap FFE in combination with a multi-tap DFE is proposed. Simulation of the architecture using a random input data stream is used to reveal the required DFE tap filter depth to effectively eliminate the dominant ISI and reflection based error components.

A microfabricated hybrid device for DNA sequencing.

PubMed

Liu, Shaorong

2003-11-01

We have created a hybrid device of a microfabricated round-channel twin-T injector incorporated with a separation capillary in order to extend the straight separation distance for high speed and long readlength DNA sequencing. Semicircular grooves on glass wafers are obtained using a photomask with a narrow line-width and a standard isotropic photolithographic etching process. Round channels are made when two etched wafers are face-to-face aligned and bonded. A two-mask fabrication process has been developed to make channels of two different diameters. The twin-T injector is formed by the smaller channels whose diameter matches the bore of the separation capillary, and the "usual" separation channel, now called the connection channel, is formed by the larger ones whose diameter matches the outer diameter of the separation capillary. The separation capillary is inserted through the connection channel all the way to the twin-T injector to allow the capillary bore flush with the twin-T injector channels. The total dead-volume of the connection is estimated to be approximately 5 pL. To demonstrate the efficiency of this hybrid device, we have performed four-color DNA sequencing on it. Using a 200 microm twin-T injector coupled with a separation capillary of 20 cm effective separation distance, we have obtained readlengths of 800 plus bases at an accuracy of 98.5% in 56 min, compared to about 650 bases in 100 min on a conventional 40 cm long capillary sequencing machine under similar conditions. At an increased separation field strength and using a diluted sieving matrix, the separation time has been reduced to 20 min with a readlength of 700 bases at 98.5% base-calling accuracy.

Single Pore Translocation of Folded, Double-Stranded, and Tetra-stranded DNA through Channel of Bacteriophage Phi29 DNA Packaging Motor

PubMed Central

Haque, Farzin; Wang, Shaoying; Stites, Chris; Chen, Li; Wang, Chi; Guo, Peixuan

2015-01-01

The elegant architecture of the channel of bacteriophage phi29 DNA packaging motor has inspired the development of biomimetics for biophysical and nanobiomedical applications. The reengineered channel inserted into a lipid membrane exhibits robust electrophysiological properties ideal for precise sensing and fingerprinting of dsDNA at the single-molecule level. Herein, we used single channel conduction assays to quantitatively evaluate the translocation dynamics of dsDNA as a function of the length and conformation of dsDNA. We extracted the speed of dsDNA translocation from the dwell time distribution and estimated the various forces involved in the translocation process. A ~35-fold slower speed of translocation per base pair was observed for long dsDNA, a significant contrast to the speed of dsDNA crossing synthetic pores. It was found that the channel could translocate both dsDNA with ~32% of channel current blockage and ~64% for tetra-stranded DNA (two parallel dsDNA). The calculation of both cross-sectional areas of the dsDNA and tetra-stranded DNA suggested that the blockage was purely proportional to the physical space of the channel lumen and the size of the DNA substrate. Folded dsDNA configuration was clearly reflected in their characteristic current signatures. The finding of translocation of tetra-stranded DNA with 64% blockage is in consent with the recently elucidated mechanism of viral DNA packaging via a revolution mode that requires a channel larger than the dsDNA diameter of 2 nm to provide room for viral DNA revolving without rotation. The understanding of the dynamics of dsDNA translocation in the phi29 system will enable us to design more sophisticated single pore DNA translocation devices for future applications in nanotechnology and personal medicine. PMID:25890769

Inhibition of KV7 Channels Protects the Rat Heart against Myocardial Ischemia and Reperfusion Injury.

PubMed

Hedegaard, Elise R; Johnsen, Jacob; Povlsen, Jonas A; Jespersen, Nichlas R; Shanmuganathan, Jeffrey A; Laursen, Mia R; Kristiansen, Steen B; Simonsen, Ulf; Bøtker, Hans Erik

2016-04-01

The voltage-gated KV7 (KCNQ) potassium channels are activated by ischemia and involved in hypoxic vasodilatation. We investigated the effect of KV7 channel modulation on cardiac ischemia and reperfusion injury and its interaction with cardioprotection by ischemic preconditioning (IPC). Reverse-transcription polymerase chain reaction revealed expression of KV7.1, KV7.4, and KV7.5 in the left anterior descending rat coronary artery and all KV7 subtypes (KV7.1-KV7.5) in the left and right ventricles of the heart. Isolated hearts were subjected to no-flow global ischemia and reperfusion with and without IPC. Infarct size was quantified by 2,3,5-triphenyltetrazolium chloride staining. Two blockers of KV7 channels, XE991 [10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone] (10 µM) and linopirdine (10 µM), reduced infarct size and exerted additive infarct reduction to IPC. An opener of KV7 channels, flupirtine (10 µM) abolished infarct size reduction by IPC. Hemodynamics were measured using a catheter inserted in the left ventricle and postischemic left ventricular recovery improved in accordance with reduction of infarct size and deteriorated with increased infarct size. XE991 (10 µM) reduced coronary flow in the reperfusion phase and inhibited vasodilatation in isolated small branches of the left anterior descending coronary artery during both simulated ischemia and reoxygenation. KV7 channels are expressed in rat coronary arteries and myocardium. Inhibition of KV7 channels exerts cardioprotection and opening of KV7 channels abrogates cardioprotection by IPC. Although safety issues should be further addressed, our findings suggest a potential role for KV7 blockers in the treatment of ischemia-reperfusion injury. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

Method for producing a thin sample band in a microchannel device

DOEpatents

Griffiths, Stewart K [Livermore, CA; Nilson, Robert H [Cardiff, CA

2004-08-03

The present invention improves the performance of microchannel systems for chemical and biological synthesis and analysis by providing a method and apparatus for producing a thin band of a species sample. Thin sample bands improve the resolution of microchannel separation processes, as well as many other processes requiring precise control of sample size and volume. The new method comprises a series of steps in which a species sample is manipulated by controlled transport through a junction formed at the intersection of four or more channels. A sample is first inserted into the end of one of these channels in the vicinity of the junction. Next, this sample is thinned by transport across the junction one or more times. During these thinning steps, flow enters the junction through one of the channels and exists through those remaining, providing a divergent flow field that progressively stretches and thins the band with each traverse of the junction. The thickness of the resulting sample band may be smaller than the channel width. Moreover, the thickness of the band may be varied and controlled by altering the method alone, without modification to the channel or junction geometries. The invention is applicable to both electroosmotic and electrophoretic transport, to combined electrokinetic transport, and to some special cases in which bulk fluid transport is driven by pressure gradients. It is further applicable to channels that are open, filled with a gel or filled with a porous or granular material.

Apparatus for producing a thin sample band in a microchannel system

DOEpatents

Griffiths, Stewart K [Livermore, CA; Nilson, Robert H [Cardiff, CA

2008-05-13

The present invention improves the performance of microchannel systems for chemical and biological synthesis and analysis by providing a method and apparatus for producing a thin band of a species sample. Thin sample bands improve the resolution of microchannel separation processes, as well as many other processes requiring precise control of sample size and volume. The new method comprises a series of steps in which a species sample is manipulated by controlled transport through a junction formed at the intersection of four or more channels. A sample is first inserted into the end of one of these channels in the vicinity of the junction. Next, this sample is thinned by transport across the junction one or more times. During these thinning steps, flow enters the junction through one of the channels and exists through those remaining, providing a divergent flow field that progressively stretches and thins the band with each traverse of the junction. The thickness of the resulting sample band may be smaller than the channel width. Moreover, the thickness of the band may be varied and controlled by altering the method alone, without modification to the channel or junction geometries. The invention is applicable to both electroosmotic and electrophoretic transport, to combined electrokinetic transport, and to some special cases in which bulk fluid transport is driven by pressure gradients. It is further applicable to channels that are open, filled with a gel or filled with a porous or granular material.

Accounting for the exact degeneracy and quasidegeneracy in the automerization of cyclobutadiene via multireference coupled-cluster methods.

PubMed

Li, Xiangzhu; Paldus, Josef

2009-09-21

The automerization of cyclobutadiene (CBD) is employed to test the performance of the reduced multireference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that employs a modest-size MR CISD wave function as an external source for the most important (primary) triples and quadruples in order to account for the nondynamic correlation effects in the presence of quasidegeneracy, as well as of its perturbatively corrected version accounting for the remaining (secondary) triples [RMR CCSD(T)]. The experimental results are compared with those obtained by the standard CCSD and CCSD(T) methods, by the state universal (SU) MR CCSD and its state selective or state specific (SS) version as formulated by Mukherjee et al. (SS MRCC or MkMRCC) and, wherever available, by the Brillouin-Wigner MRCC [MR BWCCSD(T)] method. Both restricted Hartree-Fock (RHF) and multiconfigurational self-consistent field (MCSCF) molecular orbitals are employed. For a smaller STO-3G basis set we also make a comparison with the exact full configuration interaction (FCI) results. Both fundamental vibrational energies-as obtained via the integral averaging method (IAM) that can handle anomalous potentials and automatically accounts for anharmonicity- and the CBD automerization barrier for the interconversion of the two rectangular structures are considered. It is shown that the RMR CCSD(T) potential has the smallest nonparallelism error relative to the FCI potential and the corresponding fundamental vibrational frequencies compare reasonably well with the experimental ones and are very close to those recently obtained by other authors. The effect of anharmonicity is assessed using the second-order perturbation theory (MP2). Finally, the invariance of the RMR CC methods with respect to orbital rotations is also examined.

Conceptual physics differences by pedagogy and gender: Questioning the deficit model

NASA Astrophysics Data System (ADS)

Majors, Twanelle Deann Walker

The differences in physics performance between males and females have been studied extensively (Blue & Heller, 2003; Coletta, 2015; Madsen, McKagan, & Sayre 2013; McCullough, 2002, 2004, 2011; Pollock, Finkelstein, & Kost, 2007; Zohar & Sela, 2003). The purpose of this study was to look at the ways teaching methods and assessment choices have fabricated a gender gap. Deficit ways of thinking have further marginalized women by renegotiating prior acts of power that initiated and perpetuated marginalization. Outside of the deficit model, the blame for the underperformance of females has been attributed to discourses of power as well as less-than-critical ways of evaluating learning and schooling. Students in introductory algebra-based physics courses from 2008-2014 at Tennessee Technological University were self-enrolled in PHYS2010 sections that were taught using either a traditional or constructivist, interactive-engagement Learner-centered Environment for Algebra-based Physics (LEAP) pedagogy. Propensity scoring on all feasible and relevant independent variables was used to adjust for the probability of students choosing either LEAP or traditional sections. The Force Concept Inventory (FCI) and Gender Force Concept Inventory (GFCI) were used as the measures to gauge students' performance on physics concepts. The results showed that there were no differences in the FCI or GFCI performance of males and females. Results also showed that when accounting for pretest performance and the likelihood of choosing a LEAP section, LEAP pedagogy accounted for roughly 30% of performance differences. Not only was this true on the average, it was true for both genders. This meant that the main effect of LEAP pedagogy was even stronger and more generalizable. Gender did not moderate pedagogy, indicating that a pedagogy gap focus was more appropriate for evaluating physics learners.

Validation of a stream and riparian habitat assessment protocol using stream salamanders in the southwest Virginia coalfields

USGS Publications Warehouse

Sweeten, Sara E.; Ford, W. Mark

2016-01-01

Within the central Appalachia Coalfields, the aquatic impacts of large-scale land uses, such as surface mining, are of particular ecological concern. Identification and quantification of land use impacts to aquatic ecosystems are a necessary first step to aid in mitigation of negative consequences to biota. However, quantifying physical environmental quality such as stream and riparian habitat often can be quite difficult, particularly when there is time or fiscal limitations. As such, standard protocols such as the U.S. EPA’s Stream Habitat Rapid Bioassessment Protocol have been established to be cost- and time-effective. This protocol estimates ten different stream and riparian conditions on a scale of 0 to 20. Unfortunately, using estimations can be problematic because of large potential variation in the scoring depending on differences in training, experience, and opinion of the personnel doing the estimations. In order to help negate these biases and provide a simplified process, the U.S. Army Corps of Engineers (USACE) developed a functional assessment for streams that measures 11 stream and riparian variables along with watershed land use to calculate three different scores, a hydrology score, biogeochemical score, and habitat score. In our study, we examined the correlation of stream salamander presence and abundance to the three USACE scores. In the summer of 2013, we visited 70 sites in the southwest Virginia Coalfields multiple times to collect salamanders and quantify stream and riparian microhabitat parameters. Using occupancy and abundance analyses, we found strong relationships among three Desmognathus spp. and the USACE Habitat FCI score. Accordingly, the Habitat FCI score provides a reasonable assessment of physical instream and riparian conditions that may serve as a surrogate for understanding the community composition and integrity of aquatic salamander in the region.

Very high stability systems: LMJ target alignment system and MTG imager test setup

NASA Astrophysics Data System (ADS)

Compain, Eric; Maquet, Philippe; Kunc, Thierry; Marque, Julien; Lauer-Solelhac, Maxime; Delage, Laurent; Lanternier, Catherine

2015-09-01

Most of space instruments and research facilities require test equipment with demanding opto-mechanical stability. In some specific cases, when the stability performance directly drives the final performance of the scientific mission and when feasibility is questionable, specific methods must be implemented for the associated technical risk management. In present paper, we will present our heritage in terms of methodology, design, test and the associated results for two specific systems : the SOPAC-POS and the MOTA, generating new references for future developments. From a performance point of view, we will emphasis on following key parameters : design symmetry, thermal load management, and material and structural choices. From a method point of view the difficulties arise first during design, from the strong coupling between the thermal, mechanical and optical performance models, and then during testing, from the difficulty of conceiving test setup having appropriate performance level. We will present how these limitations have been overcome. SOPAC-POS is the target alignment system of the LMJ, Laser Mega Joule, the French inertial confinement fusion research center. Its stability has been demonstrated by tests in 2014 after 10 years of research and development activities, achieving 1μm stability @ 6m during one hour periods. MOTA is an Optical Ground Support Equipment aiming at qualifying by tests the Flexible Combined Imager (FCI). FCI is an instrument for the meteorological satellite MTG-I, a program of and funded by the European Space Agency and under prime contractorship of Thales Alenia Space. Optimized design will allow to get better than 0.2 μrad stability for one hour periods, as required for MTF measurement.

Financial Capacity Following Traumatic Brain Injury: A Six-Month Longitudinal Study

PubMed Central

Dreer, Laura E.; DeVivo, Michael J.; Novack, Thomas A.; Marson, Daniel C.

2015-01-01

Objective To longitudinally investigate financial capacity (FC) following traumatic brain injury (TBI). Design Longitudinal study comparing FC in cognitively healthy adults and persons with moderate to severe TBI at time of acute hospitalization (Time 1) and at six months post injury (Time 2). Setting Inpatient brain injury rehabilitation unit. Participants Twenty healthy adult controls and 24 adult persons with moderate to severe TBI. Main Outcome Measures Participants were administered the Financial Capacity Instrument (FCI-9), a standardized instrument that measures performance on eighteen financial tasks, nine domains, and two global scores. Between and within group differences were examined for each FCI-9 domain and global scores. Using control group referenced cut scores, participants with TBI were also assigned an impairment rating (intact, marginal, or impaired) on each domain and global score. Results At Time 1, participants with TBI performed significantly below controls on the majority of financial variables tested. At Time 2, participants with TBI demonstrated within group improvement on both simple and complex financial skills, but continued to perform below adult controls on complex financial skills and both global scores. Group by time interactions were significant for five domains and both global scores. At Time 1, high percentages of participants with TBI were assigned either ‘marginal’ or ‘impaired’ ratings on the domains and global scores, with significant percentage increases of ‘intact’ ratings at Time 2. Conclusions Immediately following acute injury, persons with moderate to severe TBI show global impairment of FC. Findings indicate improvement of both simple and complex financial skills over a six month period, but continued impairment on more complex financial skills. Future studies should examine loss and recovery of FC following TBI over longer time periods and a wider range of injury severity. PMID:22369113

Performance evaluation of parallel electric field tunnel field-effect transistor by a distributed-element circuit model

NASA Astrophysics Data System (ADS)

Morita, Yukinori; Mori, Takahiro; Migita, Shinji; Mizubayashi, Wataru; Tanabe, Akihito; Fukuda, Koichi; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shin-ichi; Liu, Yongxun; Masahara, Meishoku; Ota, Hiroyuki

2014-12-01

The performance of parallel electric field tunnel field-effect transistors (TFETs), in which band-to-band tunneling (BTBT) was initiated in-line to the gate electric field was evaluated. The TFET was fabricated by inserting an epitaxially-grown parallel-plate tunnel capacitor between heavily doped source wells and gate insulators. Analysis using a distributed-element circuit model indicated there should be a limit of the drain current caused by the self-voltage-drop effect in the ultrathin channel layer.

Redesigning Channel-Forming Peptides: Amino Acid Substitutions that Enhance Rates of Supramolecular Self-Assembly and Raise Ion Transport Activity

PubMed Central

Shank, Lalida P.; Broughman, James R.; Takeguchi, Wade; Cook, Gabriel; Robbins, Ashley S.; Hahn, Lindsey; Radke, Gary; Iwamoto, Takeo; Schultz, Bruce D.; Tomich, John M.

2006-01-01

Three series of 22-residue peptides derived from the transmembrane M2 segment of the glycine receptor α1-subunit (M2GlyR) have been designed, synthesized, and tested to determine the plasticity of a channel-forming sequence and to define whether channel pores with enhanced conductive properties could be created. Sixteen sequences were examined for aqueous solubility, solution-association tendency, secondary structure, and half-maximal concentration for supramolecular assembly, channel activity, and ion transport properties across epithelial monolayers. All peptides interact strongly with membranes: associating with, inserting across, and assembling to form homooligomeric bundles when in micromolar concentrations. Single and double amino acid replacements involving arginine and/or aromatic amino acids within the final five C-terminal residues of the peptide cause dramatic effects on the concentration dependence, yielding a range of K1/2 values from 36 ± 5 to 390 ± 220 μM for transport activity. New water/lipid interfacial boundaries were established for the transmembrane segment using charged or aromatic amino acids, thus limiting the peptides' ability to move perpendicularly to the plane of the bilayer. Formation of discrete water/lipid interfacial boundaries appears to be necessary for efficient supramolecular assembly and high anion transport activity. A peptide sequence is identified that may show efficacy in channel replacement therapy for channelopathies such as cystic fibrosis. PMID:16387776

Characterization and optimization of an eight-channel time-multiplexed pulse-shaping system

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

Dorrer, Christophe; Bittle, Wade A.; Cuffney, Robert

High-performance optical pulse shaping is paramount to photonics and lasers applications for which high-resolution optical waveforms must be generated. We investigate the design and performance of a time-multiplexed pulse shaping (TMPS) system in which optical waveforms from a single pulse-shaping unit are demultiplexed and retimed before being sent to different optical systems. This architecture has the advantages of low cost and low relative jitter between optical waveforms because a single pulse-shaping system, e.g., a high-performance arbitrary waveform generator driving a Mach-Zehnder modulator, generates all the waveforms. We demonstrate an eight-channel TMPS system based on a 1 × 8 LiNbO 3more » demultiplexer composed of four stages of 1 × 2 Δβ phase-reversal switches that allow for demultiplexing and extinction enhancement via application of a control voltage modifying the propagation constant difference between adjacent waveguides. It is shown that optimal demultiplexing, i.e. low insertion loss and high extinction ratio between channels, requires optimization in dynamic operation because of the slow component of the switches’ response. Lastly, we demonstrate losses lower than 5 dB, extinction ratios of the order of 70 dB for a four-channel system and 50 dB for an eight-channel system, and jitter added by the demultiplexer smaller than 0.1 ps.« less

Characterization and optimization of an eight-channel time-multiplexed pulse-shaping system

DOE PAGES

Dorrer, Christophe; Bittle, Wade A.; Cuffney, Robert; ...

2016-12-06

High-performance optical pulse shaping is paramount to photonics and lasers applications for which high-resolution optical waveforms must be generated. We investigate the design and performance of a time-multiplexed pulse shaping (TMPS) system in which optical waveforms from a single pulse-shaping unit are demultiplexed and retimed before being sent to different optical systems. This architecture has the advantages of low cost and low relative jitter between optical waveforms because a single pulse-shaping system, e.g., a high-performance arbitrary waveform generator driving a Mach-Zehnder modulator, generates all the waveforms. We demonstrate an eight-channel TMPS system based on a 1 × 8 LiNbO 3more » demultiplexer composed of four stages of 1 × 2 Δβ phase-reversal switches that allow for demultiplexing and extinction enhancement via application of a control voltage modifying the propagation constant difference between adjacent waveguides. It is shown that optimal demultiplexing, i.e. low insertion loss and high extinction ratio between channels, requires optimization in dynamic operation because of the slow component of the switches’ response. Lastly, we demonstrate losses lower than 5 dB, extinction ratios of the order of 70 dB for a four-channel system and 50 dB for an eight-channel system, and jitter added by the demultiplexer smaller than 0.1 ps.« less

Discrete-state representation of ion permeation coupled to fast gating in a model of ClC chloride channels: comparison to multi-ion continuous space Brownian dynamics simulations.

PubMed

Coalson, Rob D; Cheng, Mary Hongying

2010-01-28

A discrete-state model of chloride ion motion in a ClC chloride channel is constructed, following a previously developed multi-ion continuous space model of the same system (Cheng, M. H.; Mamonov, A. B.; Dukes, J. W.; Coalson, R. D. J. Phys. Chem. B 2007, 111, 5956) that included a simplistic representation of the fast gate in this channel. The reducibility of the many-body continuous space to the eight discrete-state model considered in the present work is examined in detail by performing three-dimensional Brownian dynamics simulations of each allowed state-to-state transition in order to extract the appropriate rate constant for this process, and then inserting the pairwise rate constants thereby obtained into an appropriate set of kinetic master equations. Experimental properties of interest, including the rate of Cl(-) ion permeation through the open channel and the average rate of closing of the fast gate as a function of bulk Cl(-) ion concentrations in the intracellular and extracellular electrolyte reservoirs are computed. Good agreement is found between the results obtained via the eight discrete-state model versus the multi-ion continuous space model, thereby encouraging continued development of the discrete-state model to include more complex behaviors observed experimentally in these channels.

Manipulation of heat-diffusion channel in laser thermal lithography.

PubMed

Wei, Jingsong; Wang, Yang; Wu, Yiqun

2014-12-29

Laser thermal lithography is a good alternative method for forming small pattern feature size by taking advantage of the structural-change threshold effect of thermal lithography materials. In this work, the heat-diffusion channels of laser thermal lithography are first analyzed, and then we propose to manipulate the heat-diffusion channels by inserting thermal conduction layers in between channels. Heat-flow direction can be changed from the in-plane to the out-of-plane of the thermal lithography layer, which causes the size of the structural-change threshold region to become much smaller than the focused laser spot itself; thus, nanoscale marks can be obtained. Samples designated as "glass substrate/thermal conduction layer/thermal lithography layer (100 nm)/thermal conduction layer" are designed and prepared. Chalcogenide phase-change materials are used as thermal lithography layer, and Si is used as thermal conduction layer to manipulate heat-diffusion channels. Laser thermal lithography experiments are conducted on a home-made high-speed rotation direct laser writing setup with 488 nm laser wavelength and 0.90 numerical aperture of converging lens. The writing marks with 50-60 nm size are successfully obtained. The mark size is only about 1/13 of the focused laser spot, which is far smaller than that of the light diffraction limit spot of the direct laser writing setup. This work is useful for nanoscale fabrication and lithography by exploiting the far-field focusing light system.

High Performance 50 nm InAlAs/In0.75GaAs Metamorphic High Electron Mobility Transistors with Si3N4 Passivation on Thin InGaAs Layer

NASA Astrophysics Data System (ADS)

Yeon, Seongjin; Seo, Kwangseok

2008-04-01

We fabricated 50 nm InAlAs/InGaAs metamorphic high electron mobility transistors (HEMTs) with a very thin barrier. Through the reduction of the gate-channel distance (dGC) in the epitaxial structure, a channel aspect ratio (ARC) of over three was achieved when Lg was 50 nm. We inserted a thin InGaAs layer as a protective layer, and tested various gate structures to reduce surface problems induced by barrier shrinkage and to optimize the device characteristics. Through the optimization of the gate structure with the thin InGaAs layer, the fabricated 50 nm metamorphic HEMT exhibited high DC and RF characteristics, Gm of 1.5 S/mm, and fT of 490 GHz.

An Experimental Examination of the Loss-of-Flow Accident Phenomenon for Prototypical ITER Divertor Channels of Y = 0 and Y = 2

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

Marshall, Theron D.; McDonald, Jimmie M.; Cadwallader, Lee C.

2000-01-15

This paper discusses the thermal response of two prototypical International Thermonuclear Experimental Reactor (ITER) divertor channels during simulated loss-of-flow-accident (LOFA) experiments. The thermal response was characterized by the time-to-burnout (TBO), which is a figure of merit on the mockups' survivability. Data from the LOFA experiments illustrate that (a) the pre-LOFA inlet velocity does not significantly influence the TBO, (b) the incident heat flux (IHF) does influence the TBO, and (c) a swirl tape insert significantly improves the TBO and promotes the initiation of natural circulation. This natural circulation enabled the mockup to absorb steady-state IHFs after the coolant circulation pumpmore » was disabled. Several methodologies for thermal-hydraulic modeling of the LOFA were attempted.« less

An experimental examination of the loss-of-flow accident phenomenon for prototypical ITER divertor channels of Y=0 and Y=2

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

Marshall, T.D.; McDonald, J.M.; Cadwallader, L.C.

2000-01-01

This paper discusses the thermal response of two prototypical International Thermonuclear Experimental Reactor (ITER) divertor channels during simulated loss-of-flow-accident (LOFA) experiments. The thermal response was characterized by the time-to-burnout (TBO), which is a figure of merit on the mockups' survivability. Data from the LOFA experiments illustrate that (a) the pre-LOFA inlet velocity does not significantly influence the TBO, (b) the incident heat flux (IHF) does influence the TBO, and (c) a swirl tape insert significantly improves the TBO and promotes the initiation of natural circulation. This natural circulation enabled the mockup to absorb steady-state IHFs after the coolant circulation pumpmore » was disabled. Several methodologies for thermal-hydraulic modeling of the LOFA were attempted.« less

Application of Peterson's stray light model to complex optical instruments

NASA Astrophysics Data System (ADS)

Fray, S.; Goepel, M.; Kroneberger, M.

2016-07-01

Gary L. Peterson (Breault Research Organization) presented a simple analytical model for in- field stray light evaluation of axial optical systems. We exploited this idea for more complex optical instruments of the Meteosat Third Generation (MTG) mission. For the Flexible Combined Imager (FCI) we evaluated the in-field stray light of its three-mirroranastigmat telescope, while for the Infrared Sounder (IRS) we performed an end-to-end analysis including the front telescope, interferometer and back telescope assembly and the cold optics. A comparison to simulations will be presented. The authors acknowledge the support by ESA and Thales Alenia Space through the MTG satellites program.

Interband excitations in the 1D limit of two-band fractional Chern insulators

NASA Astrophysics Data System (ADS)

Jaworowski, Błażej; Kaczmarkiewicz, Piotr; Potasz, Paweł; Wójs, Arkadiusz

2018-05-01

We investigate the stability of the one-dimensional limit of ν = 1 / 3 Laughlin-like fractional Chern insulator with respect to the interband interaction. We propose a construction for the excitations in the infinite-interaction case and show that the energy gap remains finite in the thermodynamic limit. Next, by means of exact diagonalization and Density Matrix Renormalization Group approaches, we consider deviations from ideal dimerization and show that they reduce the stability of the FCI-like states. Finally, to show that our approach is not restricted to one model, we identify the dimer structure behind the thin-torus limit of other system - the checkerboard lattice.

Interpretation of symmetry experiments on Omega

NASA Astrophysics Data System (ADS)

Lours, Laurence; Bastian, Josiane; Monteil, Marie-Christine; Philippe, Franck; Jadaud, Jean-Paul

2006-10-01

The interpretation of the symmetry experiments performed on Omega in 2005 with 3 cone LMJ-like irradiation is presented here. The goal of this campaign was the characterization of the irradiation symmetry by X-ray imaging of the D2Ar capsule. Images of backlit implosion (as done in earlier campaigns with foam balls) and core emission were obtained on the same shot, and can be compared to FCI2 simulations. This set of shots comfirms former results with foam balls of a good symmetry control with 3 cones in empty hohlraums. The influence of the hohlraum shape on symmetry is also studied by comparison of cylindrical hohlraums vs rugby ones.

When a transmembrane channel isn't, or how biophysics and biochemistry (mis)communicate.

PubMed

Reviakine, Ilya

2018-02-12

Annexins are a family of soluble proteins that bind to acidic phospholipids such as phosphatidylserine in a calcium-dependent manner. The archetypical member of the annexin family is annexin A5. For many years, its function remained unknown despite the availability of a high-resolution structure. This, combined with the observations of specific ion conductance in annexin-bound membranes, fueled speculations about the possible membrane-spanning forms of annexins that functioned as ion channels. The channel hypothesis remained controversial and did not gather sufficient evidence to become accepted. Yet, it continues to draw attention as a framework for interpreting indirect (e.g., biochemical) data. The goal of the mini-review is to examine the data on annexin-lipid interactions from the last ~30 years from the point of view of the controversy between the two lines of inquiry: the well-characterized peripheral assembly of the annexins at membranes vs. their putative transmembrane insertion. In particular, the potential role of lipid rearrangements induced by annexin binding is highlighted. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis of Aprotinin, a Protease Inhibitor, Action on the Trafficking of Epithelial Na+ Channels (ENaC) in Renal Epithelial Cells Using a Mathematical Model.

PubMed

Sasamoto, Kouhei; Marunaka, Rie; Niisato, Naomi; Sun, Hongxin; Taruno, Akiyuki; Pezzotti, Giuseppe; Yamamoto, Toshiro; Kanamura, Narisato; Zhu, Wenliang; Nishio, Kyosuke; Inui, Toshio; Eaton, Douglas C; Marunaka, Yoshinori

2017-01-01

Epithelial Na+ channels (ENaC) play a crucial role in control of blood pressure by regulating renal Na+ reabsorption. Intracellular trafficking of ENaC is one of the key regulators of ENaC function, but a quantitative description of intracellular recycling of endogenously expressed ENaC is unavailable. We attempt here to provide a model for intracellular recycling after applying a protease inhibitor under hypotonic conditions. We simulated the ENaC-mediated Na+ transport in renal epithelial A6 cells measured as short-circuit currents using a four-state mathematical ENaC trafficking model. We developed a four-state mathematical model of ENaC trafficking in the cytosol of renal epithelial cells that consists of: an insertion state of ENaC that can be trafficked to the apical membrane state (insertion rate); an apical membrane state of ENaC conducting Na+ across the apical membrane; a recycling state containing ENaC that are retrieved from the apical membrane state (endocytotic rate) and then to the insertion state (recycling rate) communicating with the apical membrane state or to a degradation state (degradation rate). We studied the effect of aprotinin (a protease inhibitor) blocking protease-induced cleavage of the extracellular loop of γ ENaC subunit on the rates of intracellular ENaC trafficking using the above-defined four-state mathematical model of ENaC trafficking and the recycling number relative to ENaC staying in the apical membrane. We found that aprotinin significantly reduced the insertion rate of ENaC to the apical membrane by 40%, the recycling rate of ENaC by 81%, the cumulative time of an individual ENaC staying in the apical membrane by 32%, the cumulative life-time after the first endocytosis of ENaC by 25%, and the cumulative Na+ absorption by 31%. The most interesting result of the present study is that cleavage of ENaC affects the intracellular ENaC trafficking rate and determines the residency time of ENaC, indicating that more active cleaved ENaCs stay longer at the apical membrane contributing to transcellular Na+ transport via an increase in recycling of ENaC to the apical membrane. The extracellular protease-induced cleavage of the extracellular loop of γ ENaC subunit increases transcellular epithelial Na+ transport by elevating the recycling rate of ENaC due to an increase in the recycling rate of ENaCs associated with increases in the insertion rate of ENaC. © 2017 The Author(s). Published by S. Karger AG, Basel.

Core Dynamics Analysis for Reactivity Insertion and Loss of Coolant Flow Tests Using the High Temperature Engineering Test Reactor

NASA Astrophysics Data System (ADS)

Takamatsu, Kuniyoshi; Nakagawa, Shigeaki; Takeda, Tetsuaki

Safety demonstration tests using the High Temperature Engineering Test Reactor (HTTR) are in progress to verify its inherent safety features and improve the safety technology and design methodology for High-temperature Gas-cooled Reactors (HTGRs). The reactivity insertion test is one of the safety demonstration tests for the HTTR. This test simulates the rapid increase in the reactor power by withdrawing the control rod without operating the reactor power control system. In addition, the loss of coolant flow tests has been conducted to simulate the rapid decrease in the reactor power by tripping one, two or all out of three gas circulators. The experimental results have revealed the inherent safety features of HTGRs, such as the negative reactivity feedback effect. The numerical analysis code, which was named-ACCORD-, was developed to analyze the reactor dynamics including the flow behavior in the HTTR core. We have modified this code to use a model with four parallel channels and twenty temperature coefficients. Furthermore, we added another analytical model of the core for calculating the heat conduction between the fuel channels and the core in the case of the loss of coolant flow tests. This paper describes the validation results for the newly developed code using the experimental results. Moreover, the effect of the model is formulated quantitatively with our proposed equation. Finally, the pre-analytical result of the loss of coolant flow test by tripping all gas circulators is also discussed.

The role of AlGaN buffers and channel thickness in the electronic transport properties of Al{sub x}In{sub 1–x}N/AlN/GaN heterostructures

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

Amirabbasi, M., E-mail: mo.amirabbasi@gmail.com

We try to theoretically analyze the reported experimental data of the Al{sub x}In{sub 1–x}N/AlN/GaN heterostructures grown by MOCVD and quantitatively investigate the effects of AlGaN buffers and the GaNchannel thickness on the electrical transport properties of these systems. Also, we obtain the most important effective parameters of the temperature-dependent mobility in the range 35–300 K. Our results show that inserting a 1.1 μm thick Al{sub 0.04}Ga{sub 0.96}N buffer enhances electron mobility by decreasing the effect of phonons, the interface roughness, and dislocation and crystal defect scattering mechanisms. Also, as the channel thickness increases from 20 nm to 40 nm, themore » electron mobility increases from 2200 to 2540 cm{sup 2}/(V s) and from 870 to 1000 cm{sup 2}/(V s) at 35 and 300 K respectively, which is attributed to the reduction in the dislocation density and the strain-induced field. Finally, the reported experimental data show that inserting a 450 nm graded AlGaN layer before an Al{sub 0.04}Ga{sub 0.96}N buffer causes a decrease in the electron mobility, which is attributed to the enhancement of the lateral size of roughness, the dislocation density, and the strain-induced field in this sample.« less

Direct coupling of polymer-based microchip electrophoresis to online MALDI-MS using a rotating ball inlet.

PubMed

Musyimi, Harrison K; Guy, Jason; Narcisse, Damien A; Soper, Steven A; Murray, Kermit K

2005-12-01

We report on the coupling of a polymer-based microfluidic chip to a MALDI-TOF MS using a rotating ball interface. The microfluidic chips were fabricated by micromilling a mold insert into a brass plate, which was then used for replicating polymer microparts via hot embossing. Assembly of the chip was accomplished by thermally annealing a cover slip to the embossed substrate to enclose the channels. The linear separation channel was 50 microm wide, 100 microm deep, and possessed an 8 cm effective length separation channel with a double-T injector (V(inj) = 10 nL). The exit of the separation channel was machined to allow direct contact deposition of effluent onto a specially constructed rotating ball inlet to the mass spectrometer. Matrix addition was accomplished in-line on the surface of the ball. The coupling utilized the ball as the cathode transfer electrode to transport sample into the vacuum for desorption with a 355 nm Nd:YAG laser and analyzed on a TOF mass spectrometer. The ball was cleaned online after every rotation. The ability to couple poly(methylmethacrylate) microchip electrophoresis devices for the separation of peptides and peptide fragments produced from a protein digest with subsequent online MALDI MS detection was demonstrated.

The Arabidopsis vacuolar malate channel is a member of the ALMT family.

PubMed

Kovermann, Peter; Meyer, Stefan; Hörtensteiner, Stefan; Picco, Cristiana; Scholz-Starke, Joachim; Ravera, Silvia; Lee, Youngsook; Martinoia, Enrico

2007-12-01

In plants, malate is a central metabolite and fulfills a large number of functions. Vacuolar malate may reach very high concentrations and fluctuate rapidly, whereas cytosolic malate is kept at a constant level allowing optimal metabolism. Recently, a vacuolar malate transporter (Arabidopsis thaliana tonoplast dicarboxylate transporter, AttDT) was identified that did not correspond to the well-characterized vacuolar malate channel. We therefore hypothesized that a member of the aluminum-activated malate transporter (ALMT) gene family could code for a vacuolar malate channel. Using GFP fusion constructs, we could show that AtALMT9 (A. thaliana ALMT9) is targeted to the vacuole. Promoter-GUS fusion constructs demonstrated that this gene is expressed in all organs, but is cell-type specific as GUS activity in leaves was detected nearly exclusively in mesophyll cells. Patch-clamp analysis of an Atalmt9 T-DNA insertion mutant exhibited strongly reduced vacuolar malate channel activity. In order to functionally characterize AtALMT9 as a malate channel, we heterologously expressed this gene in tobacco and in oocytes. Overexpression of AtALMT9-GFP in Nicotiana benthamiana leaves strongly enhanced the malate current densities across the mesophyll tonoplasts. Functional expression of AtALMT9 in Xenopus oocytes induced anion currents, which were clearly distinguishable from endogenous oocyte currents. Our results demonstrate that AtALMT9 is a vacuolar malate channel. Deletion mutants for AtALMT9 exhibit only slightly reduced malate content in mesophyll protoplasts and no visible phenotype, indicating that AttDT and the residual malate channel activity are sufficient to sustain the transport activity necessary to regulate the cytosolic malate homeostasis.

A Developmental Framework for Complex Plasmodesmata Formation Revealed by Large-Scale Imaging of the Arabidopsis Leaf Epidermis[W

PubMed Central

Fitzgibbon, Jessica; Beck, Martina; Zhou, Ji; Faulkner, Christine; Robatzek, Silke; Oparka, Karl

2013-01-01

Plasmodesmata (PD) form tubular connections that function as intercellular communication channels. They are essential for transporting nutrients and for coordinating development. During cytokinesis, simple PDs are inserted into the developing cell plate, while during wall extension, more complex (branched) forms of PD are laid down. We show that complex PDs are derived from existing simple PDs in a pattern that is accelerated when leaves undergo the sink–source transition. Complex PDs are inserted initially at the three-way junctions between epidermal cells but develop most rapidly in the anisocytic complexes around stomata. For a quantitative analysis of complex PD formation, we established a high-throughput imaging platform and constructed PDQUANT, a custom algorithm that detected cell boundaries and PD numbers in different wall faces. For anticlinal walls, the number of complex PDs increased with increasing cell size, while for periclinal walls, the number of PDs decreased. Complex PD insertion was accelerated by up to threefold in response to salicylic acid treatment and challenges with mannitol. In a single 30-min run, we could derive data for up to 11k PDs from 3k epidermal cells. This facile approach opens the door to a large-scale analysis of the endogenous and exogenous factors that influence PD formation. PMID:23371949

Modulation of innate immune responses by Yersinia type III secretion system translocators and effectors.

PubMed

Bliska, James B; Wang, Xiaoying; Viboud, Gloria I; Brodsky, Igor E

2013-10-01

The innate immune system of mammals responds to microbial infection through detection of conserved molecular determinants called 'pathogen-associated molecular patterns' (PAMPs). Pathogens use virulence factors to counteract PAMP-directed responses. The innate immune system can in turn recognize signals generated by virulence factors, allowing for a heightened response to dangerous pathogens. Many Gram-negative bacterial pathogens encode type III secretion systems (T3SSs) that translocate effector proteins, subvert PAMP-directed responses and are critical for infection. A plasmid-encoded T3SS in the human-pathogenic Yersinia species translocates seven effectors into infected host cells. Delivery of effectors by the T3SS requires plasma membrane insertion of two translocators, which are thought to form a channel called a translocon. Studies of the Yersinia T3SS have provided key advances in our understanding of how innate immune responses are generated by perturbations in plasma membrane and other signals that result from translocon insertion. Additionally, studies in this system revealed that effectors function to inhibit innateimmune responses resulting from insertion of translocons into plasma membrane. Here, we review these advances with the goal of providing insight into how a T3SS can activate and inhibit innate immune responses, allowing a virulent pathogen to bypass host defences. © 2013 John Wiley & Sons Ltd.

Different structural requirements for functional ion pore transplantation suggest different gating mechanisms of NMDA and kainate receptors.

PubMed

Villmann, Carmen; Hoffmann, Jutta; Werner, Markus; Kott, Sabine; Strutz-Seebohm, Nathalie; Nilsson, Tanja; Hollmann, Michael

2008-10-01

Although considerable progress has been made in characterizing the physiological function of the high-affinity kainate (KA) receptor subunits KA1 and KA2, no homomeric ion channel function has been shown. An ion channel transplantation approach was employed in this study to directly test if homomerically expressed KA1 and KA2 pore domains are capable of conducting currents. Transplantation of the ion pore of KA1 or KA2 into GluR6 generated perfectly functional ion channels that allowed characterization of those electrophysiological and pharmacological properties that are determined exclusively by the ion pore of KA1 or KA2. This demonstrates for the first time that KA1 and KA2 ion pore domains are intrinsically capable of conducting ions even in homomeric pore assemblies. NMDA receptors, similar to KA1- or KA2-containing receptors, function only as heteromeric complexes. They are composed of NR1 and NR2 subunits, which both are non-functional when expressed homomerically. In contrast to NR1, the homomeric NR2B ion pore failed to translate ligand binding into pore opening when transplanted into GluR6. Similarly, heteromeric coexpression of the ion channel domains of both NR1 and NR2 inserted into GluR6 failed to produce functional channels. Therefore, we conclude that the mechanism underlying the ion channel opening in the obligatorily heterotetrameric NMDA receptors differs significantly from that in the facultatively heterotetrameric alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate and KA receptors.

TACT1- TRANSIENT THERMAL ANALYSIS OF A COOLED TURBINE BLADE OR VANE EQUIPPED WITH A COOLANT INSERT

NASA Technical Reports Server (NTRS)

Gaugler, R. E.

1994-01-01

As turbine-engine core operating conditions become more severe, designers must develop more effective means of cooling blades and vanes. In order to design reliable, cooled turbine blades, advanced transient thermal calculation techniques are required. The TACT1 computer program was developed to perform transient and steady-state heat-transfer and coolant-flow analyses for cooled blades, given the outside hot-gas boundary condition, the coolant inlet conditions, the geometry of the blade shell, and the cooling configuration. TACT1 can analyze turbine blades, or vanes, equipped with a central coolant-plenum insert from which coolant-air impinges on the inner surface of the blade shell. Coolant-side heat-transfer coefficients are calculated with the heat transfer mode at each station being user specified as either impingement with crossflow, forced convection channel flow, or forced convection over pin fins. A limited capability to handle film cooling is also available in the program. The TACT1 program solves for the blade temperature distribution using a transient energy equation for each node. The nodal energy balances are linearized, one-dimensional, heat-conduction equations which are applied at the wall-outer-surface node, at the junction of the cladding and the metal node, and at the wall-inner-surface node. At the mid-metal node a linear, three-dimensional, heat-conduction equation is used. Similarly, the coolant pressure distribution is determined by solving the set of transfer momentum equations for the one-dimensional flow between adjacent fluid nodes. In the coolant channel, energy and momentum equations for one-dimensional compressible flow, including friction and heat transfer, are used for the elemental channel length between two coolant nodes. The TACT1 program first obtains a steady-state solution using iterative calculations to obtain convergence of stable temperatures, pressures, coolant-flow split, and overall coolant mass balance. Transient calculations are based on the steady-state solutions obtained. Input to the TACT1 program includes a geometrical description of the blade and insert, the nodal spacing to be used, and the boundary conditions describing the outside hot-gas and the coolant-inlet conditions. The program output includes the value of nodal temperatures and pressures at each iteration. The final solution output includes the temperature at each coolant node, and the coolant flow rates and Reynolds numbers. This program is written in FORTRAN IV for batch execution and has been implemented on an IBM 360 computer with a central memory requirement of approximately 480K of 8 bit bytes. The TACT1 program was developed in 1978.

Spin injection into silicon in three-terminal vertical and four-terminal lateral devices with Fe/Mg/MgO/Si tunnel junctions having an ultrathin Mg insertion layer

NASA Astrophysics Data System (ADS)

Sato, Shoichi; Nakane, Ryosho; Hada, Takato; Tanaka, Masaaki

2017-12-01

We demonstrate that the spin injection/extraction efficiency is enhanced by an ultrathin Mg insertion layer (⩽2 nm) in Fe /Mg /MgO /n+-Si tunnel junctions. In diode-type vertical three-terminal devices fabricated on a Si substrate, we observe the narrower three-terminal Hanle (N-3TH) signals indicating true spin injection into Si and estimate the spin polarization in Si to be 16% when the thickness of the Mg insertion layer is 1 nm, whereas no N-3TH signal is observed without the Mg insertion. This means that the spin injection/extraction efficiency is enhanced by suppressing the formation of a magnetically dead layer at the Fe/MgO interface. We also observe clear spin transport signals, such as nonlocal Hanle signals and spin-valve signals, in a lateral four-terminal device with the same Fe /Mg /MgO /n+-Si tunnel junctions fabricated on a Si-on-insulator substrate. It is found that both the intensity and linewidth of the spin signals are affected by the geometrical effects (device geometry and size). We have derived analytical functions taking into account the device structures, including channel thickness and electrode size, and estimated important parameters: spin lifetime and spin polarization. Our analytical functions explain the experimental results very well. Our study shows the importance of suppressing a magnetically dead layer and provides a unified understanding of spin injection/detection signals in different device geometries.

Electrophysiological characterization of 14-benzoyltalatisamine, a selective blocker of the delayed rectifier K+ channel found in virtual screening.

PubMed

Song, Ming-Ke; Liu, Hong; Jiang, Hua-Liang; Yue, Jian-Min; Hu, Guo-Yuan

2006-02-15

14-Benzoyltalatisamine is a potent and selective blocker of the delayed rectifier K+ channel found in a computational virtual screening study. The compound was found to block the K+ channel from the extracellular side. However, it is unclear whether 14-benzoyltalatisamine shares the same block mechanism with tetraethylammonium (TEA). In order to elucidate how the hit compound found by the virtual screening interacts with the outer vestibule of the K+ channel, the effects of 14-benzoyltalatisamine and TEA on the delayed rectifier K+ current of rat dissociated hippocampal neurons were compared using whole-cell voltage-clamp recording. External application of 14-benzoyltalatisamine and TEA reversibly inhibited the current with IC50 values of 10.1+/-2.2 microM and 1.05+/-0.21 mM, respectively. 14-Benzoyltalatisamine exerted voltage-dependent inhibition, markedly accelerated the decay of the current, and caused a significant hyperpolarizing shift of the steady-state activation curve, whereas TEA caused voltage-independent inhibition, without affecting the kinetic parameters of the current. The blockade by 14-benzoyltalatisamine, but not by TEA, was significantly diminished in a high K+ (60 mM) external solution. The potency of 14-benzoyltalatisamine was markedly reduced in the presence of 15 mM TEA. The results suggest that 14-benzoyltalatisamine bind to the external pore entry of the delayed rectifier K+ channel with partial insertion into the selectivity filter, which is in conformity with that predicted by the molecular docking model in the virtual screening.

Amino acid residues involved in membrane insertion and pore formation of Clostridium botulinum C2 toxin.

PubMed

Lang, Alexander E; Neumeyer, Tobias; Sun, Jianjun; Collier, R John; Benz, Roland; Aktories, Klaus

2008-08-12

The actin-ADP-ribosylating Clostridium botulinum C2 toxin consists of the enzymatic component C2I and the binding component C2II. C2II forms heptameric channels involved in translocation of the enzymatic component into the target cell. On the basis of the heptameric toxin channel, we studied functional consequences of mutagenesis of amino acid residues probably lining the lumen of the toxin channel. Substitution of glutamate-399 of C2II with alanine blocked channel formation and cytotoxicity of the holotoxin. Although cytotoxicity and rounding up of cells by C2I were completely blocked by exchange of phenylalanine-428 with alanine, the mutation increased potassium conductance caused by C2II in artificial membranes by about 2-3-fold over that of wild-type toxin. In contrast to its effects on single-channel potassium conductance in artificial membranes, the F428A mutation delayed the kinetics of pore formation in lipid vesicles and inhibited the activity of C2II in promoting (86)Rb (+) release from preloaded intact cells after pH shift of the medium. Moreover, F428A C2II exhibited delayed and diminished formation of C2II aggregates at low pH, indicating major changes of the biophysical properties of the toxin. The data indicate that phenylalanine-428 of C2II plays a major role in conformational changes occurring during pore formation of the binding component of C2II.

Development of remountable joints and heat removable techniques for high-temperature superconducting magnets

NASA Astrophysics Data System (ADS)

Hashizume, H.; Ito, S.; Yanagi, N.; Tamura, H.; Sagara, A.

2018-02-01

Segment fabrication is now a candidate for the design of superconducting helical magnets in the helical fusion reactor FFHR-d1, which adopts the joint winding of high-temperature superconducting (HTS) helical coils as a primary option and the ‘remountable’ HTS helical coil as an advanced option. This paper reports on recent progress in two key technologies: the mechanical joints (remountable joints) of the HTS conductors and the metal porous media inserted into the cooling channel for segment fabrication. Through our research activities it has been revealed that heat treatment during fabrication of the joint can reduce joint resistance and its dispersion, which can shorten the fabrication process and be applied to bent conductor joints. Also, heat transfer correlations of the cooling channel were established to evaluate heat transfer performance with various cryogenic coolants based on the correlations to analyze the thermal stability of the joint.

Generation regimes of bidirectional hybridly mode-locked ultrashort pulse erbium-doped all-fiber ring laser with a distributed polarizer.

PubMed

Krylov, Alexander A; Chernykh, Dmitriy S; Arutyunyan, Natalia R; Grebenyukov, Vyacheslav V; Pozharov, Anatoly S; Obraztsova, Elena D

2016-05-20

We report on the stable picosecond and femtosecond pulse generation from the bidirectional erbium-doped all-fiber ring laser hybridly mode-locked with a coaction of a single-walled carbon nanotube-based saturable absorber and nonlinear polarization evolution that was introduced through the insertion of the short-segment polarizing fiber. Depending on the total intracavity dispersion value, the laser emits conservative solitons, transform-limited Gaussian pulses, or highly chirped stretched pulses with almost 20 nm wide parabolic spectrum in both clockwise (CW) and counterclockwise (CCW) directions of the ring. Owing to the polarizing action in the cavity, we have demonstrated for the first time, to the best of our knowledge, an efficient tuning of soliton pulse characteristics for both CW and CCW channels via an appropriate polarization control. We believe that the bidirectional laser presented may be highly promising for gyroscopic and other dual-channel applications.

Method and system for fiber optic determination of gas concentrations in liquid receptacles

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet (Inventor)

2008-01-01

A system for determining gas compositions includes a probe, inserted into a source of gaseous material, the probe having a gas permeable sensor tip and being capable of sending and receiving light to and from the gaseous material, a sensor body, connected to the probe, situated outside of the source and a fiber bundle, connected to the sensor body and communicating light to and from the probe. The system also includes a laser source, connected to one portion of the fiber bundle and providing laser light to the fiber bundle and the probe a Raman spectrograph, connected to another portion of the fiber bundle, receiving light from the probe and filtering the received light into specific channels and a data processing unit, receiving and analyzing the received light in the specific channels and outputting concentration of specific gas species in the gaseous material based on the analyzed received light.

Stretchable Metamaterial Absorber Using Liquid Metal-Filled Polydimethylsiloxane (PDMS)

PubMed Central

Kim, Kyeongseob; Lee, Dongju; Eom, Seunghyun; Lim, Sungjoon

2016-01-01

A stretchable metamaterial absorber is proposed in this study. The stretchability was achieved by liquid metal and polydimethylsiloxane (PDMS). To inject liquid metal, microfluidic channels were fabricated using PDMS powers and microfluidic-channel frames, which were built using a three-dimensional printer. A top conductive pattern and ground plane were designed after considering the easy injection of liquid metal. The proposed metamaterial absorber comprises three layers of PDMS substrate. The top layer is for the top conductive pattern, and the bottom layer is for the meandered ground plane. Flat PDMS layers were inserted between the top and bottom PDMS layers. The measured absorptivity of the fabricated absorber was 97.8% at 18.5 GHz, and the absorption frequency increased from 18.5 to 18.65 GHz as the absorber was stretched from its original length (5.2 cm) to 6.4 cm. PMID:27077861

Development of fast cooling pulsed magnets at the Wuhan National High Magnetic Field Center.

PubMed

Peng, Tao; Sun, Quqin; Zhao, Jianlong; Jiang, Fan; Li, Liang; Xu, Qiang; Herlach, Fritz

2013-12-01

Pulsed magnets with fast cooling channels have been developed at the Wuhan National High Magnetic Field Center. Between the inner and outer sections of a coil wound with a continuous length of CuNb wire, G10 rods with cross section 4 mm × 5 mm were inserted as spacers around the entire circumference, parallel to the coil axis. The free space between adjacent rods is 6 mm. The liquid nitrogen flows freely in the channels between these rods, and in the direction perpendicular to the rods through grooves provided in the rods. For a typical 60 T pulsed magnetic field with pulse duration of 40 ms, the cooling time between subsequent pulses is reduced from 160 min to 35 min. Subsequently, the same technology was applied to a 50 T magnet with 300 ms pulse duration. The cooling time of this magnet was reduced from 480 min to 65 min.

Office-based endoscopic botulinum toxin injection in laryngeal movement disorders.

PubMed

Kaderbay, A; Righini, C A; Castellanos, P F; Atallah, I

2018-06-01

Botulinum toxin injection is widely used for the treatment of laryngeal movement disorders. Electromyography-guided percutaneous injection is the technique most commonly used to perform intralaryngeal botulinum toxin injection. We describe an endoscopic approach for intralaryngeal botulinum toxin injection under local anaesthesia without using electromyography. A flexible video-endoscope with an operating channel is used. After local anaesthesia of the larynx by instillation of lidocaine, a flexible needle is inserted into the operating channel in order to inject the desired dose of botulinum toxin into the vocal and/or vestibular folds. Endoscopic botulinum toxin injection under local anaesthesia is a reliable technique for the treatment of laryngeal movement disorders. It can be performed by any laryngologist without the need for electromyography. It is easy to perform for the operator and comfortable for the patient. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Multi-party Semi-quantum Key Agreement with Delegating Quantum Computation

NASA Astrophysics Data System (ADS)

Liu, Wen-Jie; Chen, Zhen-Yu; Ji, Sai; Wang, Hai-Bin; Zhang, Jun

2017-10-01

A multi-party semi-quantum key agreement (SQKA) protocol based on delegating quantum computation (DQC) model is proposed by taking Bell states as quantum resources. In the proposed protocol, the participants only need the ability of accessing quantum channel and preparing single photons {|0〉, |1〉, |+〉, |-〉}, while the complicated quantum operations, such as the unitary operations and Bell measurement, will be delegated to the remote quantum center. Compared with previous quantum key agreement protocols, this client-server model is more feasible in the early days of the emergence of quantum computers. In order to prevent the attacks from outside eavesdroppers, inner participants and quantum center, two single photon sequences are randomly inserted into Bell states: the first sequence is used to perform the quantum channel detection, while the second is applied to disorder the positions of message qubits, which guarantees the security of the protocol.

Lateral release of proteins from the TOM complex into the outer membrane of mitochondria.

PubMed

Harner, Max; Neupert, Walter; Deponte, Marcel

2011-07-15

The TOM complex of the outer membrane of mitochondria is the entry gate for the vast majority of precursor proteins that are imported into the mitochondria. It is made up by receptors and a protein conducting channel. Although precursor proteins of all subcompartments of mitochondria use the TOM complex, it is not known whether its channel can only mediate passage across the outer membrane or also lateral release into the outer membrane. To study this, we have generated fusion proteins of GFP and Tim23 which are inserted into the inner membrane and, at the same time, are spanning either the TOM complex or are integrated into the outer membrane. Our results demonstrate that the TOM complex, depending on sequence determinants in the precursors, can act both as a protein conducting pore and as an insertase mediating lateral release into the outer membrane.

Cell Calcium and the Control of Membrane Transport. Annual Symposium of the Society of General Physiologists (40th) Held in Woods Hole, Massachusetts on September 3-7, 1986.

DTIC Science & Technology

1986-01-01

physiological functions: to alter the composition of the cell surface, for instance, by the insertion of receptors, channels, and pumps, and to release into the...localized alterations in lipid composition might serve to facilitate fusion under some circumstances, the involvement of proteins specialized for...594. Reuter. H., and N. Seitz. 1968. The dependence of Ca2* efllux from cardiac muscle on temperature and external ion composition . Journal o/Phywidoo

Board-level optical clock signal distribution using Si CMOS-compatible polyimide-based 1- to 48-fanout H-tree

NASA Astrophysics Data System (ADS)

Wu, Linghui; Bihari, Bipin; Gan, Jianhua; Chen, Ray T.; Tang, Suning

1998-08-01

Si-CMOS compatible polymer-based waveguides for optoelectronic interconnects and packaging have been fabricated and characterized. A 1-to-48 fanout optoelectronic interconnection layer (OIL) structure based on Ultradel 9120/9020 for the high-speed massive clock signal distribution for a Cray T-90 supercomputer board has been constructed. The OIL employs multimode polymeric channel waveguides in conjunction with surface-normal waveguide output coupler and 1-to-2 splitter. A total insertion loss of 7.98 dB at 850 nm was measured experimentally.

Management of JJ stent-related symptoms.

PubMed

Papatsoris, Athanasios; Dellis, Athanasios; Daglas, George; Sanguedolce, Francesco

2014-01-01

Ureteric JJ stents are inserted in numerous pa- tients as a routine procedure. Nevertheless, the ideal JJ stent that does not cause any lower urinary tract symptoms has not been developed yet. Even special validated ques- tionnaires have been used for the assessment of JJ stent-related symtoms. For the management of such symtoms usually alpha-blockers are admin- istered. Also, studies have examined the efficacy and safety of anticholinergics and calcium channel blo- ckers. In this article we review the literature upon the management of JJ stent-related symptoms.

Superlattice structure modeling and simulation of High Electron Mobility Transistor for improved performance

NASA Astrophysics Data System (ADS)

Munusami, Ravindiran; Yakkala, Bhaskar Rao; Prabhakar, Shankar

2013-12-01

Magnetic tunnel junction were made by inserting the magnetic materials between the source, channel and the drain of the High Electron Mobility Transistor (HEMT) to enhance the performance. Material studio software package was used to design the superlattice layers. Different cases were analyzed to optimize the performance of the device by placing the magnetic material at different positions of the device. Simulation results based on conductivity reveals that the device has a very good electron transport due to the magnetic materials and will amplify very low frequency signals.

Intraluminal measurement of papillary duct urine pH, in vivo: a pilot study in the swine kidney.

PubMed

Handa, Rajash K; Lingeman, James E; Bledsoe, Sharon B; Evan, Andrew P; Connors, Bret A; Johnson, Cynthia D

2016-06-01

We describe the in vivo use of an optic-chemo microsensor to measure intraluminal papillary duct urine pH in a large mammal. Fiber-optic pH microsensors have a tip diameter of 140-µm that allows insertion into papillary Bellini ducts to measure tubule urine proton concentration. Anesthetized adult pigs underwent percutaneous nephrolithotomy to access the lower pole of the urinary collecting system. A flexible nephroscope was advanced towards an upper pole papilla with the fiber-optic microsensor contained within the working channel. The microsensor was then carefully inserted into Bellini ducts to measure tubule urine pH in real time. We successfully recorded tubule urine pH values in five papillary ducts from three pigs (1 farm pig and 2 metabolic syndrome Ossabaw pigs). Our results demonstrate that optical microsensor technology can be used to measure intraluminal urine pH in real time in a living large mammal. This opens the possibility for application of this optical pH sensing technology in nephrolithiasis.

Solvent history dependence of gramicidin A conformations in hydrated lipid bilayers.

PubMed Central

LoGrasso, P V; Moll, F; Cross, T A

1988-01-01

Reconstituted lipid bilayers of dimyristoylphosphatidylcholine (DMPC) and gramicidin A' have been prepared by cosolubilizing gramicidin and DMPC in one of three organic solvent systems followed by vacuum drying and hydration. The conformational state of gramicidin as characterized by 23Na NMR, circular dichroism, and solid state 15N NMR is dependent upon the cosolubilizing solvent system. In particular, two conformational states are described; a state in which Na+ has minimal interactions with the polypeptide, referred to as a nonchannel state, and a state in which Na+ interacts very strongly with the polypeptide, referred to as the channel state. Both of these conformations are intimately associated with the hydrophobic core of the lipid bilayer. Furthermore, both of these states are stable in the bilayer at neutral pH and at a temperature above the bilayer phase transition temperature. These results with gramicidin suggest that the conformation of membrane proteins may be dictated by the conformation before membrane insertion and may be dependent upon the mechanism by which the insertion is accomplished. PMID:2462923

Miniature Wireless BioSensor for Remote Endoscopic Monitoring

NASA Astrophysics Data System (ADS)

Nemiroski, Alex; Brown, Keith; Issadore, David; Westervelt, Robert; Thompson, Chris; Obstein, Keith; Laine, Michael

2009-03-01

We have built a miniature wireless biosensor with fluorescence detection capability that explores the miniaturization limit for a self-powered sensor device assembled from the latest off-the-shelf technology. The device is intended as a remote medical sensor to be inserted endoscopically and remainin a patient's gastrointestinal tract for a period of weeks, recording and transmitting data as necessary. A sensing network may be formed by using multiple such devices within the patient, routing information to an external receiver that communicates through existing mobilephone networks to relay data remotely. By using a monolithic IC chip with integrated processor, memory, and 2.4 GHz radio,combined with a photonic sensor and miniature battery, we have developed a fully functional computing device in a form factorcompliantwith insertion through the narrowest endoscopic channels (less than 3mm x 3mm x 20mm). We envision similar devices with various types of sensors to be used in many different areas of the human body.

Texas Science Teacher Characteristics and Conceptual Understanding of Newton's Laws of Motion

NASA Astrophysics Data System (ADS)

Busby, Karin Burk

Misconceptions of Newtonian mechanics and other physical science concepts are well documented in primary and pre-service teacher populations (Burgoon, Heddle, & Duran, 2009; Allen & Coole, 2012; Kruger, Summers, & Palacio, 1990; Ginns & Watters, 1995; Trumper, 1999; Asikainen & Hirovonen, 2014). These misconceptions match the misconceptions held by students, leaving teachers ill-equipped to rectify these concepts in the classroom (Kind, 2014; Kruger et al., 1990; Cochran & Jones, 1998). Little research has been devoted to misconceptions held by in-service secondary teachers, the population responsible for teaching Newtonian mechanics. This study focuses on Texas in-service science teachers in middle school and high school science, specifically sixth grade science, seventh grade science, eighth grade science, integrated physics and chemistry, and physics teachers. This study utilizes two instruments to gauge conceptual understanding of Newton's laws of motion: the Force Concept Inventory [FCI] (Hestenes, Wells, & Swackhamer, 1992) and a custom instrument developed for the Texas Regional Collaboratives for Excellence in Science and Mathematics Teaching (Urquhart, M., e-mail, April 4, 2017). Use of each instrument had its strengths and limitations. In the initial work of this study, the FCI was given to middle and high school teacher volunteers in two urban school districts in the Dallas- Fort Worth area to assess current conceptual understanding of Newtonian mechanics. Along with the FCI, each participant was asked to complete a demographic survey. Demographic data collected included participant's sex, years of service in teaching position, current teaching position, degrees, certification type, and current certifications for science education. Correlations between variables and overall average on the FCI were determined by t-tests and ANOVA tests with a post-hoc Holm-Bonferroni correction test. Test questions pertaining to each of Newton's three laws of motion were extrapolated to determine any correlations. The sample size for this study was small (n=24), requiring a second study investigate potential correlations to teacher characteristics. The second study was conducted using the 2013-2014 school year participants in the Texas Regional Collaboratives for Excellence in Science and Mathematics Teaching [TRC] (Texas Regional Collaborative for Excellence in Science and Mathematics Teaching, 2013), a statewide program led by The University of Texas at Austin Center for STEM Education (Texas Regional Collaborative for Excellence in Science and Mathematics Teaching, 2013). Participants completed a demographic survey and took the TRC Physics Assessment instrument developed for the TRC to determine current conceptual understanding of Newtonian mechanics as defined by the Texas Essential Knowledge and Skills. The TRC also collected demographic data including Texas Educational Agency region, participant's sex, years of service in teaching, current teaching position, level of highest degree earned, whether or not the participant had a STEM degree, and certification type. Correlations were determined between overall average and conceptual force questions only. The sample size was substantial (n=368) but due to time constraints in its development, the TRC Physics Assessment was unable to undergo reliability or validity testing before implementation. Test question pertaining to each of Newton's three laws of motion were extrapolated to determine any correlations. A significance value of p= 0.05 was used for all tests. Both content assessments indicated that, on average, teacher-participants had a considerable misunderstanding of Newtonian mechanics with Newton's third law questions especially difficult for the populations. Teachers' current teaching assignment was statistically significant for most tests, suggesting that high school physics teachers have more conceptual understanding of Newtonian mechanics than middle school teachers but have not necessarily mastered Newtonian mechanics. STEM majors and participant's sex were significant only for the TRC Physics Assessment. One outcome of this study is a recommendation that the Texas teacher certification process for middle school science change to include a general science test that includes physical science. Also, in-service science teachers responsible for teaching Newton's laws of motion should participate in specific professional development from a physics content educational expert to address misconceptions. Additional recommendations include that physics teachers take a mentoring role to help other teachers in physical science concepts and that middle school curriculum provide assistance to teachers for addressing misconceptions of Newton's third law.

Toxic β-Amyloid (Aβ) Alzheimer's Ion Channels: From Structure to Function and Design

NASA Astrophysics Data System (ADS)

Nussinov, Ruth

2012-02-01

Full-length amyloid beta peptides (Aβ1-40/42) form neuritic amyloid plaques in Alzheimer's disease (AD) patients and are implicated in AD pathology. Recent biophysical and cell biological studies suggest a direct mechanism of amyloid beta toxicity -- ion channel mediated loss of calcium homeostasis. Truncated amyloid beta fragments (Aβ11-42 and Aβ17-42), commonly termed as non-amyloidogenic are also found in amyloid plaques of Alzheimer's disease (AD) and in the preamyloid lesions of Down's syndrome (DS), a model system for early onset AD study. Very little is known about the structure and activity of these smaller peptides although they could be key AD and DS pathological agents. Using complementary techniques of explicit solvent molecular dynamics (MD) simulations, atomic force microscopy (AFM), channel conductance measurements, cell calcium uptake assays, neurite degeneration and cell death assays, we have shown that non-amyloidogenic Aβ9-42 and Aβ17-42 peptides form ion channels with loosely attached subunits and elicit single channel conductances. The subunits appear mobile suggesting insertion of small oligomers, followed by dynamic channel assembly and dissociation. These channels allow calcium uptake in APP-deficient cells and cause neurite degeneration in human cortical neurons. Channel conductance, calcium uptake and neurite degeneration are selectively inhibited by zinc, a blocker of amyloid ion channel activity. Thus truncated Aβ fragments could account for undefined roles played by full length Aβs and provide a novel mechanism of AD and DS pathology. The emerging picture from our large-scale simulations is that toxic ion channels formed by β-sheets are highly polymorphic, and spontaneously break into loosely interacting dynamic units (though still maintaining ion channel structures as imaged with AFM), that associate and dissociate leading to toxic ion flux. This sharply contrasts intact conventional gated ion channels that consist of tightly interacting α-helices that robustly prevent ion leakage, rather than hydrogen-bonded β-strands. Moreover, in comparison with β-rich antimicrobial peptide (AMP) such as a protegrin-1 (PG-1), both Aβ and PG-1 are cytotoxic, and capable of forming fibrils and dynamic channels which consist of subunits with similar dimensions. These combined properties support a functional relationship between amyloidogenic peptides and β-sheet-rich cytolytic AMPs, suggesting that PG-1 is amyloidogenic and amyloids may have an antimicrobial function.

Activation of renal ClC-K chloride channels depends on an intact N terminus of their accessory subunit barttin.

PubMed

Wojciechowski, Daniel; Thiemann, Stefan; Schaal, Christina; Rahtz, Alina; de la Roche, Jeanne; Begemann, Birgit; Becher, Toni; Fischer, Martin

2018-06-01

ClC-K channels belong to the CLC family of chloride channels and chloride/proton antiporters. They contribute to sodium chloride reabsorption in Henle's loop of the kidney and to potassium secretion into the endolymph by the stria vascularis of the inner ear. Their accessory subunit barttin stabilizes the ClC-K/barttin complex, promotes its insertion into the surface membrane, and turns the pore-forming subunits into a conductive state. Barttin mutations cause Bartter syndrome type IV, a salt-wasting nephropathy with sensorineural deafness. Here, studying ClC-K/barttin channels heterologously expressed in MDCK-II and HEK293T cells with confocal imaging and patch-clamp recordings, we demonstrate that the eight-amino-acids-long barttin N terminus is required for channel trafficking and activation. Deletion of the complete N terminus (Δ2-8 barttin) retained barttin and human hClC-Ka channels in intracellular compartments. Partial N-terminal deletions did not compromise subcellular hClC-Ka trafficking but drastically reduced current amplitudes. Sequence deletions encompassing Thr-6, Phe-7, or Arg-8 in barttin completely failed to activate hClC-Ka. Analyses of protein expression and whole-cell current noise revealed that inactive channels reside in the plasma membrane. Substituting the deleted N terminus with a polyalanine sequence was insufficient for recovering chloride currents, and single amino acid substitutions highlighted that the correct sequence is required for proper function. Fast and slow gate activation curves obtained from rat V166E rClC-K1/barttin channels indicated that mutant barttin fails to constitutively open the slow gate. Increasing expression of barttin over that of ClC-K partially recovered this insufficiency, indicating that N-terminal modifications of barttin alter both binding affinities and gating properties. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

MifM monitors total YidC activities of Bacillus subtilis, including that of YidC2, the target of regulation.

PubMed

Chiba, Shinobu; Ito, Koreaki

2015-01-01

The YidC/Oxa1/Alb3 family proteins are involved in membrane protein biogenesis in bacteria, mitochondria, and chloroplasts. Recent studies show that YidC uses a channel-independent mechanism to insert a class of membrane proteins into the membrane. Bacillus subtilis has two YidC homologs, SpoIIIJ (YidC1) and YidC2 (YqjG); the former is expressed constitutively, while the latter is induced when the SpoIIIJ activity is compromised. MifM is a substrate of SpoIIIJ, and its failure in membrane insertion is accompanied by stable ribosome stalling on the mifM-yidC2 mRNA, which ultimately facilitates yidC2 translation. While mutational inactivation of SpoIIIJ has been known to induce yidC2 expression, here, we show that the level of this induction is lower than that observed when the membrane insertion signal of MifM is defective. Moreover, this partial induction of YidC2 translation is lowered further when YidC2 is overexpressed in trans. These results suggest that YidC2 is able to insert MifM into the membrane and to release its translation arrest. Thus, under SpoIIIJ-deficient conditions, YidC2 expression is subject to MifM-mediated autogenous feedback repression. Our results show that YidC2 uses a mechanism that is virtually identical to that used by SpoIIIJ; Arg75 of YidC2 in its intramembrane yet hydrophilic cavity is functionally indispensable and requires negatively charged residues of MifM as an insertion substrate. From these results, we conclude that MifM monitors the total activities of the SpoIIIJ and the YidC2 pathways to control the synthesis of YidC2 and to maintain the cellular capability of the YidC mode of membrane protein biogenesis. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

A Summary of Source Data in Military Psychiatric Epidemiology

DTIC Science & Technology

1975-12-01

AD-A02 1 265 A SUMMARY OF SOURCE DATA IN MILITARY PSYCHIATRIC EPIDEMIOLOGY Willia m E. Datel Walter Reed Army Institute of Research Washington...1 1.1 1 ’? • ~) 1 J•·" n .I.• I •.o .1 l’ , ..-.~ nt .# 1 a. 1 l... I - j_ l· ,,, ,, .. _ ... f f •d ’ M t H\\• ( rl’ . , ’ I ·~·· f N l U A’ f fC...i llnesn acror:s ;■ L L three f-erviccr- ::; u/ierofore attenuated. :•!. .!;(.’i.; i. ;;ere, -7- ■■■ -■ --■ - -■■■■.■■=—^-^^-i^* m .""- Bfcl m

Decoding the Assessment Alphabet Soup

NASA Astrophysics Data System (ADS)

Engelhardt, Paula

2010-10-01

The number of assessment instruments that help physics instructors evaluate the conceptual learning of their students has grown over the last twenty years. Today, the number of tests that are available begin to look like an alphabet soup, FCI, MBT, TUG-K, CSE, CSM, CSEM, DIRECT, BEMA, LOCE, FMCE, SEMCO, etc. What can these assessment tests do for you that is different from what you regularly do? How do these tests differ from the tests and other assessments you already give in class? What is meant by formative and summative assessment and why should you care? What are some of the issues associated with giving one of these assessment tests? These are the questions that will be addressed in this talk.

New Methods for the Detection and Interception of Frequency-Hopped Waveforms

DTIC Science & Technology

1990-11-01

that £[p2 Q2 /O] = uF + 2 + o(cos 0 + 6 sin9)2 + 4n(acos0+/3sin)(7ycos0+6sinO)+o r(acos0+sinO)2 I + ( acosO +/3sinO) 2(Tcos9+ 6sin O)2 (3.134) i which...Jcins I lopk ins lI mvtrsi! t3 A pplied Physics Laborator Before1 NII After Figure 4.4: Deconvolut ion Applivod to Oi-fFci i r 100 The Johns 11opkins...Arlington, VA 20360 Library 2 Naval Postgraduate School Monterey, CA 92940 Library 2 Naval Research Laborator . Washington, DC 20375 Library 2 J. W

Alternative splice isoforms of small conductance calcium-activated SK2 channels differ in molecular interactions and surface levels

PubMed Central

Scholl, Elizabeth Storer; Pirone, Antonella; Cox, Daniel H; Duncan, R Keith; Jacob, Michele H

2014-01-01

Small conductance Ca2+-sensitive potassium (SK2) channels are voltage-independent, Ca2+-activated ion channels that conduct potassium cations and thereby modulate the intrinsic excitability and synaptic transmission of neurons and sensory hair cells. In the cochlea, SK2 channels are functionally coupled to the highly Ca2+ permeant α9/10-nicotinic acetylcholine receptors (nAChRs) at olivocochlear postsynaptic sites. SK2 activation leads to outer hair cell hyperpolarization and frequency-selective suppression of afferent sound transmission. These inhibitory responses are essential for normal regulation of sound sensitivity, frequency selectivity, and suppression of background noise. However, little is known about the molecular interactions of these key functional channels. Here we show that SK2 channels co-precipitate with α9/10-nAChRs and with the actin-binding protein α-actinin-1. SK2 alternative splicing, resulting in a 3 amino acid insertion in the intracellular 3′ terminus, modulates these interactions. Further, relative abundance of the SK2 splice variants changes during developmental stages of synapse maturation in both the avian cochlea and the mammalian forebrain. Using heterologous cell expression to separately study the 2 distinct isoforms, we show that the variants differ in protein interactions and surface expression levels, and that Ca2+ and Ca2+-bound calmodulin differentially regulate their protein interactions. Our findings suggest that the SK2 isoforms may be distinctly modulated by activity-induced Ca2+ influx. Alternative splicing of SK2 may serve as a novel mechanism to differentially regulate the maturation and function of olivocochlear and neuronal synapses. PMID:24394769

Structural Characterization of Two Pore-Forming Peptides: Consequences of Introducing a C-Terminal Tryptophan

PubMed Central

Herrera, Alvaro I.; Al-Rawi, Ahlam; Cook, Gabriel A.; Gao, Jian; Iwamoto, Takeo; Prakash, Om; Tomich, John M.; Chen, Jianhan

2010-01-01

Synthetic channel-forming peptides that can restore chloride conductance across epithelial membranes could provide a novel treatment of channelopathies such as cystic fibrosis. Among series of 22-residue peptides derived from the second transmembrane segment of the glycine receptor α1-subunit (M2GlyR), p22-S22W (KKKKP ARVGL GITTV LTMTT QW) is particularly promising with robust membrane insertion and assembly. The concentration to reach one-half maximal short circuit current is reduced to 45±6 μM from that of 210±70 μM of peptide p22 (KKKKP ARVGL GITTV LTMTT QS). However, this is accompanied with nearly 50% reduction in conductance. Towards obtaining a molecular level understanding of the channel activities, we combine information from solution NMR, existing biophysical data, and molecular modeling to construct atomistic models of the putative pentameric channels of p22 and p22-S22W. Simulations in membrane bilayers demonstrate that these structural models, even though highly flexible, are stable and remain adequately open for ion conductance. The membrane-anchoring tryptophan residues not only rigidify the whole channel, suggesting increased stability, but also lead to global changes in the pore profile. Specifically, the p22-S22W pore has a smaller opening on average, consistent with lower measured conductance. Direct observation of several incidences of chloride transport suggests several qualitative features of how these channels might selectively conduct anions. The current study thus helps to rationalize the functional consequences of introducing a single C-terminal tryptophan. Availability of these structural models also paves the way for future work to rationally modify and improve M2GlyR-derived peptides toward potential peptide-based channel replacement therapy. PMID:20544961

Atomic Force Microscopy and MD Simulations Reveal Pore-Like Structures of All-D-Enantiomer of Alzheimer’s β-Amyloid Peptide: Relevance to the Ion Channel Mechanism of AD Pathology

PubMed Central

Connelly, Laura; Arce, Fernando Teran; Jang, Hyunbum; Capone, Ricardo; Kotler, Samuel A.; Ramachandran, Srinivasan; Kagan, Bruce L.; Nussinov, Ruth; Lal, Ratnesh

2012-01-01

Alzheimer’s disease (AD) is a protein misfolding disease characterized by a build-up of β-amyloid (Aβ) peptide as senile plaques, uncontrolled neurodegeneration, and memory loss. AD pathology is linked to the destabilization of cellular ionic homeostasis and involves Aβ peptide-plasma membrane interactions. In principle, there are two possible ways through which disturbance of the ionic homeostasis can take place: directly, where the Aβ peptide either inserts into the membrane and creates ion-conductive pores or destabilizes the membrane organization; or, indirectly, where the Aβ peptide interacts with existing cell membrane receptors. To distinguish between these two possible types of Aβ-membrane interactions, we took advantage of the biochemical tenet that ligand-receptor interactions are stereospecific; L-amino acid peptides, but not their D-counterparts, bind to cell membrane receptors. However, with respect to the ion channel-mediated mechanism, like L-amino acids, D-amino acid peptides will also form ion channel-like structures. Using atomic force microscopy (AFM) we imaged the structures of both D- and L-enantiomers of the full length Aβ1-42 when reconstituted in lipid bilayers. AFM imaging shows that both L- and D-Aβ isomers form similar channel-like structures. Molecular dynamics (MD) simulations support the AFM imaged 3D structures. Earlier we have shown that D-Aβ1-42 channels conduct ions similarly to their L-counter parts. Taken together, our results support the direct mechanism of Aβ ion channel-mediated destabilization of ionic homeostasis rather than the indirect mechanism through Aβ interaction with membrane receptors. PMID:22217000

Alternative actions on the K stack problem

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

Spencer, H.G.

1958-09-29

On June 6, 1958, KW Operations had HCR Channel No. 16 borescoped to determine why this rod could not be inserted on May 3. Observations revealed 3X balls in the channel and horizontal separation between graphite blocks ranging from 1/2 inch to 2 1/4 inch. The separations were noted only in the first fifteen feet in from the outer skin and in the last five feet of the channel. As a result of these findings and past operational difficulties with certain HCR`s at both KE and KW Reactors, a program of measurements is in progress to determine the extent andmore » causes of the stack displacements. From measurements and observations so far obtained, the following conclusions may be drawn about separations at locations of consequence to the loss of 3X balls from channels: Side to side horizontal separations totaling two to three inches have been observed at both reactors. The significant separations lie outside of the VSR pattern and in the lower half of the stack. The VSR pattern does not include the six outer ball 3X channels. There are probably a few small separations (< 1/2 inch) at the outer VSR`s. There are probably no separations large enough to admit balls on inner VSR channels, i.e. VSR`s inside the outer front to rear rows of VSR`s. These conclusions can not be considered fully reliable, but no information obtained to date refutes them. A team was established on 9-17-58 to evaluate and provide information on alternate courses of action for elimination or alleviation of the problem. This report contains the information and recommendations developed by the team.« less

Nanoconstricted structure for current-confined path in current-perpendicular-to-plane spin valves with high magnetoresistance

NASA Astrophysics Data System (ADS)

Fukuzawa, H.; Yuasa, H.; Koi, K.; Iwasaki, H.; Tanaka, Y.; Takahashi, Y. K.; Hono, K.

2005-05-01

We have successfully observed a nanoconstricted structure for current-confined-path (CCP) effect in current-perpendicular-to-plane-giant-magnetoresistance (CPP-GMR) spin valves. By inserting an AlCu nano-oxide layer (NOL) formed by ion-assisted oxidation (IAO) between a pinned layer and a free layer, the MR ratio was increased while maintaining a small area resistance product (RA). The cross-sectional high-resolution transmission electron microscopy image of the sample with RA =380mΩμm2, ΔRA =16mΩμm2, and MR ratio=4.3% showed that an amorphous oxide layer is a main part of the NOL that blocks the electron conduction perpendicular to plane. Some parts of the NOL are punched through crystalline, metallic channels having a diameter of a few nanometers, which are thought to work as nanoconstricted electron conduction paths between the pinned layer and the free layer. Nano-energy-dispersive-x-ray-spectrum analysis also showed that Cu is enriched in the metallic channels, whereas Al is enriched in the amorphous oxide region, indicating that the metallic channel is made of Cu and the oxide is made of Al2O3. The nanoconstricted structure with good segregation between the metallic channel and the oxide layer enables us to realize a large MR ratio in CCP-CPP spin valves.

3D-Printed Fluidic Devices for Nanoparticle Preparation and Flow-Injection Amperometry Using Integrated Prussian Blue Nanoparticle-Modified Electrodes

PubMed Central

Bishop, Gregory W.; Satterwhite, Jennifer E.; Bhakta, Snehasis; Kadimisetty, Karteek; Gillette, Kelsey M.; Chen, Eric; Rusling, James F.

2015-01-01

A consumer-grade fused filament fabrication (FFF) 3D printer was used to construct fluidic devices for nanoparticle preparation and electrochemical sensing. Devices were printed using poly(ethylene terephthalate) and featured threaded ports to connect polyetheretherketone (PEEK) tubing via printed fittings prepared from acrylonitrile butadiene styrene (ABS). These devices included channels designed to have 800 × 800 µm2 square cross sections and were semitransparent to allow visualization of the solution-filled channels. A 3D-printed device with a Y-shaped mixing channel was used to prepare Prussian blue nanoparticles (PBNPs) under flow rates of 100 to 2000 µL min−1. PBNPs were then attached to gold electrodes for hydrogen peroxide sensing. 3D-printed devices used for electrochemical measurements featured threaded access ports into which a fitting equipped with reference, counter, and PBNP-modified working electrodes could be inserted. PBNP-modified electrodes enabled amperometric detection of H2O2 in the 3D-printed channel by flow-injection analysis, exhibiting a detection limit of 100 nM and linear response up to 20 µM. These experiments show that a consumer-grade FFF printer can be used to fabricate low-cost fluidic devices for applications similar to those that have been reported with more expensive 3D-printing methods. PMID:25901660

Structural Channels and Atomic-Cluster Insertion in CsxBi4Te6 (1 ≤ x ≤ 1.25) As Observed by Aberration-Corrected Scanning Transmission Electron Microscopy.

PubMed

Zhang, Ruixin; Yang, Huaixin; Guo, Cong; Tian, Huanfang; Shi, Honglong; Chen, Genfu; Li, Jianqi

2016-12-19

Microstructural analyses based on aberration-corrected scanning transmission electron microscopy (STEM) observations demonstrate that low-dimensional Cs x Bi 4 Te 6 materials, known to be a novel thermoelectric and superconducting system, contain notable structural channels that go directly along the b axis, which can be partially filled by atom clusters depending on the thermal treatment process. We successfully prepared two series of Cs x Bi 4 Te 6 single-crystalline samples using two different sintering processes. The Cs x Bi 4 Te 6 samples prepared using an air-quenching method show superconductivity at approximately 4 K, while the Cs x Bi 4 Te 6 with the same nominal compositions prepared by slowly cooling are nonsuperconductors. Moreover, atomic structural investigations of typical samples reveal that the structural channels are often empty in superconducting materials; thus, we can represent the superconducting phase as Cs 1-y Bi 4 Te 6 with considering the point defects in the Cs layers. In addition, the channels in the nonsuperconducting crystals are commonly partially occupied by triplet Bi clusters. Moreover, the average structures for these two phases are also different in their monoclinic angles (β), which are estimated to be 102.3° for superconductors and 100.5° for nonsuperconductors.

Results of Buoyancy-gravity Effects in ITER Cable-in- Conduit Conductor with Dual Channel

NASA Astrophysics Data System (ADS)

Bruzzone, P.; Stepanov, B.; Zanino, R.; Richard, L. Savoldi

2006-04-01

The coolant in the ITER cable-in-conduit conductors (CICC) flows at significant higher speed in the central channel than in the strand bundle region due to the large difference of hydraulic impedance. When energy is deposited in the bundle region, e.g. by ac loss or radiation, the heat removal in vertically oriented dual channel CICC with the coolant flowing downward is affected by the reduced density of helium (buoyancy) in the bundle region, which is arising from the temperature gradient due to poor heat exchange between the two channels. At large deposited power, flow stagnation and back-flow can cause in the strand bundle area a slow temperature runaway eventually leading to quench. A new test campaign of the thermal-hydraulic behavior was carried out in the SULTAN facility on an instrumented section of the ITER Poloidal Field Conductor Insert (PFIS). The buoyancy-gravity effect was investigated using ac loss heating, with ac loss in the cable calibrated in separate runs. The extent of upstream temperature increase was explored over a broad range of mass flow rate and deposited power. The experimental behavior is partly reproduced by numerical simulations. The results from the tests are extrapolated to the likely operating conditions of the ITER Toroidal Field conductor with the inboard leg cooled from top to bottom and heat deposited by nuclear radiation from the burning plasma.

Polymer waveguide based hybrid opto-electric integration technology

NASA Astrophysics Data System (ADS)

Mao, Jinbin; Deng, Lingling; Jiang, Xiyan; Ren, Rong; Zhai, Yumeng; Wang, Jin

2014-10-01

While monolithic integration especially based on InP appears to be quite an expensive solution for optical devices, hybrid integration solutions using cheaper material platforms are considered powerful competitors because of the high freedom of design, yield optimization and relative cost-efficiency. Among them, the polymer planar-lightwave circuit (PLC) technology is regarded attractive as polymer offers the potential of fairly simple and low-cost fabrication, and of low-cost packaging. In our work, polymer PLC was fabricated by using the standard reactive ion etching (RIE) technique, while other active and passive devices can be integrated on the polymer PLC platform. Exemplary polymer waveguide devices was a 13-channel arrayed waveguide grating (AWG) chip, where the central channel cross-talk was below -30dB and the polarization dependent frequency shift was mitigated by inserting a half wave plate. An optical 900 hybrid was also realized with one 2×4 multi-mode interferometer (MMI). The excess insertion losses are below 4dB for the C-band, while the transmission imbalance is below 1.2dB. When such an optical hybrid was integrated vertically with mesa-type photodiodes, the responsivity of the individual PD was around 0.06 A/W, while the 3 dB bandwidth reaches 24 ~ 27 GHz, which is sufficient for 100Gbit/s receivers. Another example of the hybrid integration was to couple the polymer waveguides to fiber by applying fiber grooves, whose typical loss value was 0.2 dB per-facet over a broad spectral range from 1200-1600 nm.

The PolyScope: a modular design, semidisposable flexible ureterorenoscope system.

PubMed

Bader, Markus Juergen; Gratzke, Christian; Walther, Sebastian; Schlenker, Boris; Tilki, Derya; Hocaoglu, Yasemin; Sroka, Ronald; Stief, Christian Georg; Reich, Oliver

2010-07-01

To characterize the mechanical and optical properties of the PolyScope endoscope system and to examine the clinical outcome in patients who were undergoing ureteronephroscopy. Mechanical assessment involved measurement of the deflection angle and irrigation flow rate. Optical resolution and distortion, field and angle of view, and light transmission and output formed the optical assessment. Clinical assessment was made in a series of consecutive ureteronephroscopy procedures. The optical cord was disconnected after each procedure, and the image fiber was assessed for damage. The mean value for the angle of maximum active tip deflection with an empty working channel was 265 degrees (261-275 degrees). Deflection was impaired most with insertion of the 3.0 F basket (10% decrease) and least with an indwelling 220 microm laser fiber (2% decrease). Irrigation flow rate was 57 mL/min with an empty working channel. Flow was reduced by 50% and 68%, with the insertion of a 200 microm or 365 microm laser probe, respectively, and by 92.5% with a 3.2F basket. No damage to the image fiber occurred. The PolyScope optics system could identify a target of about 0.125 mm at a distance of 2 to 4 mm, based on 3 line-pairs/mm needed for clear identification. Lithotripsy of renal calculi was performed for 40 stone burdens in 32 patients; the resulting stone-free rate was 87.5%. The novel semidisposable ureteroscope system PolyScope was simple to use, effective, and reliable in this preliminary clinical evaluation. It overcomes the inherent fragility of comparable devices, which renders the need for maintenance unnecessary.

Design and fabrication of a continuously tuned capacitor by microfluidic actuation

NASA Astrophysics Data System (ADS)

Habbachi, Nizar; Boussetta, Hatem; Boukabache, Ali; Adel Kallala, Mohamed; Pons, Patrick; Besbes, Kamel

2018-03-01

This paper presents the design and fabrication of a continuously tunable RF MEMS capacitor using micro fluidics as a tuning parameter. The impedance variation principle is based on the modification of the capacitor gap permittivity produced by the presence of deionized (DI) water and its displacement in a channel inserted between electrodes. In addition, the electric field distribution changes in an equiponderant way according to the DI water positions in the channel. This change modifies the capacitive coupling, the stored energy and, consequently, the self-resonant frequency. The fabrication process is based on two parts: metallic paths having a spiral form, and obtained by electroplating a 7 µm thick gold layer to constitute electrodes; and fluidic channels, realized by super imposing two SU-8 films. The measurements show a nonlinear variation of the capacitor value according to the water positions. The tuning range is very large, reaching to 4650% for capacitance, and 335% for resonant frequency. However, the quality factor reaches Q max  =  79 at 550 MHz if the capacitor is empty and decreases with the fluid displacement to Q min  =  3.13.

Assessment of velocity fields through open-channel flows with an empiric law.

PubMed

Bardiaux, J B; Vazquez, J; Mosé, R

2008-01-01

Most sewer managers are currently confronted with the evaluation of the water discharges, that flow through their networks or go to the discharge system, i.e. rivers in the majority of cases. In this context, the Urban Hydraulic Systems laboratory of the ENGEES is working on the relation between velocity fields and metrology assessment through a partnership with the Fluid and Solid Mechanics Institute of Strasbourg (IMFS). The responsibility is clearly to transform a velocity profile measurement, given by a Doppler sensor developed by the IMFS team, into a water discharge evaluation. The velocity distribution in a cross section of the flow in a channel has attracted the interests of many researchers over the years, due to its practical applications. In the case of free surface flows in narrow open channels the maximum velocity is below the free surface. This phenomenon, usually called "dip-phenomenon", amongst other things, raises the problem of the area explored in the section of measurements. The work presented here tries to create a simple relation making possible to associate the flow with the velocity distribution. This step allows to insert the sensor position into the flow calculation.

Stopping electric field extension in a modified nanostructure based on SOI technology - A comprehensive numerical study

NASA Astrophysics Data System (ADS)

Anvarifard, Mohammad K.; Orouji, Ali A.

2017-11-01

This article has related a particular knowledge in order to reduce short channel effects (SCEs) in nano-devices based on silicon-on-insulator (SOI) MOSFETs. The device under study has been designed in 22 nm node technology with embedding Si3N4 extra oxide as a stopping layer of electric field and a useful heatsink for transferring generated heat. Two important subjects (DC characteristics and RF characteristics) have been investigated, simultaneously. Stopping electric field extension and enhancement of channel thermal conduction are introduced as an entrance gateway for this work so that improve the electrical characteristics, eventually. The inserted extra oxide made by the Si3N4 material has a vital impact on the modification of the electrical and thermal features in the proposed device. An immense comparison between the proposed SOI and conventional SOI showed that the proposed structure has higher electrical and thermal proficiency than the conventional structure in terms of main parameters such as short channel effects (SCEs), leakage current, floating body effect (FBE), self-heating effect (SHE), voltage gain, ratio of On-current to Off- current, transconductance, output conductance, minimum noise figure and power gain.