Sorption of adamantane phenylamide derivatives on hyper-cross-linked polystyrene from water-acetonitrile eluents

NASA Astrophysics Data System (ADS)

Shafigulin, R. V.; Konstantinov, A. V.; Bulanova, A. V.; Il'in, M. M.; Davankov, V. A.

2016-11-01

Study of the main physicochemical features of the sorption of phenylamide adamantane derivatives on hyper-cross-linked polystyrene from water-acetonitrile solutions shows that both hydrophobic and electronic interactions make a large contribution to retention, especially for a chlorine-containing derivative in which there are π- p and π- d interactions between the outer-shell electrons of the chlorine atom in addition to π- π interactions between aromatic fragments of the sorbate and sorbent.

A statistical learning approach to the modeling of chromatographic retention of oligonucleotides incorporating sequence and secondary structure data

PubMed Central

Sturm, Marc; Quinten, Sascha; Huber, Christian G.; Kohlbacher, Oliver

2007-01-01

We propose a new model for predicting the retention time of oligonucleotides. The model is based on ν support vector regression using features derived from base sequence and predicted secondary structure of oligonucleotides. Because of the secondary structure information, the model is applicable even at relatively low temperatures where the secondary structure is not suppressed by thermal denaturing. This makes the prediction of oligonucleotide retention time for arbitrary temperatures possible, provided that the target temperature lies within the temperature range of the training data. We describe different possibilities of feature calculation from base sequence and secondary structure, present the results and compare our model to existing models. PMID:17567619

Toward a mechanistic understanding of the effect of biochar addition on soil water retention

NASA Astrophysics Data System (ADS)

Yi, S.; Chang, N.; Guo, M.; Imhoff, P. T.

2014-12-01

Biochar (BC) is a carbon-rich product produced by thermal degradation of biomass in an oxygen-free environment, whose application to sediment is said to improve water retention. However, BC produced from different feedstocks and pyrolyzed at different temperatures have distinct properties, which may alter water retention in ways difficult to predict a priori. Our goal is to develop a mechanistic understanding of BC addition on water retention by examining the impact of BC from two feedstocks, poultry litter (PL) and hardwood (HW), on the soil-water retention curves (SWRC) of a uniform sand and a sandy loam (SL). For experiments with sand, BC and sand were sieved to the same particle size (~ 0.547 mm) to minimize effects of BC addition on particle size distribution. Experiments with SL contained the same sieved BC. PL and HW bicohars were added at 2 and 7% (w/w), and water retention was measured from 0 to -4.38 × 106 cm-H2O. Both BCs increased porosities for sand and SL, up to 39 and 13% for sand and SL, respectively, with 7% HW BC addition. The primary cause for these increases was the internal porosity of BC particles. While the matric potential for air-entry was unchanged with BC addition, BC amendment increased water retention for sand and SL in the capillary region (0 to -15,000 cm-H2O) by an average of 26 and 33 % for 7% PL and HW BC in sand, respectively, but only 7 and 14 % for 7% PL and HW BC in SL. The most dramatic influence of BC amendment on water retention occurred in the adsorption region (< -15,000 cm-H2O), where water retention increased by a factor of 11 and 22 for 7% PL and HW BC in sand, respectively, but by 140 and 190 % for 7% PL and HW BC in SL, respectively. The impact of BC on water retention in these sediments is explained primarily by the additional surface area and internal porosity of PL and HW BC particles. van Genuchten (VG) models were fitted to the water retention data. For SL where the impact of BC addition on water retention was less significant, a unimodal model fit water retention data well for unamended and BC-amended media: the addition of BC did not create a new class of small pores that could not be described with a unimodal VG model. While a unimodal model fitted the sand data well, a bimodal model was required for all BC-amended sand. The influence of BC type, mass fraction and sediment on water retention models will be discussed.

Multiple Family Groups for Child Behavior Difficulties Retention Among Child Welfare–Involved Caregivers

PubMed Central

Gopalan, Geetha; Fuss, Ashley; Wisdom, Jennifer P.

2013-01-01

Among children who remain at home with their permanent caregivers following a child welfare investigation, few who manifest emotional and behavioral difficulties actually engage in mental health treatment. The Multiple Family Group service delivery model to reduce childhood disruptive behavior disorders (MFG) has shown promise in engaging child welfare-involved families. This qualitative study examines caregiver perceptions of factors that influence retention in MFGs among child welfare-involved families. Methods Twenty-five predominantly Black and Hispanic adult (ages 26–57) female caregivers with child welfare services involvement participated in individual, in-depth interviews about their experience with MFGs. Transcribed interview data were thematically coded guided by grounded theory methodology. Emergent themes were subsequently organized into a conceptual framework. Results Within the overarching influence of child welfare services involvement, specific components of MFGs influencing retention included the quality of interaction among group members, group facilitators’ attentive approach with caregivers, supports designed to overcome logistical barriers (i.e., child care, transportation expenses, meals), and perceptions of MFG content and activities as fun and helpful. Caregiver factors, including their mental health and personal characteristics, as well as children’s behavior, (i.e., observed changes in behavioral difficulties) were also associated with retention. Conclusions High acceptability suggest utility for implementing MFGs within settings serving child welfare involved families, with additional modifications to tailor to setting and client features. PMID:26527856

Effects of aging and divided attention on recognition memory processes for single and associative information.

PubMed

Kinjo, Hikari

2011-04-01

In the divided attention paradigm to test age-related associative memory deficits, whether the effects of divided attention occur at encoding or retrieval has not been clarified, and the effect on retention has not been studied. This study explored whether and how much divided attention at either encoding, retention, or retrieval diminished accuracy in recognizing a single feature (object or location) and associated features (object+location) by 23 elderly people (13 women; M age = 70.6 yr., SD = 2.8) recruited from a neighborhood community circle, and 29 female college students (M age = 20.8 yr., SD = 1.1). The results showed a significant decline in memory performance for both age groups due to divided attention in location and associative memory at retention, suggesting that the retention process demands attentional resources. Overall, regardless of their relative deficiency in associative memory, older adults showed an effect of divided attention comparable to that of younger adults in a recognition task.

Mice deficient for striatal Vesicular Acetylcholine Transporter (VAChT) display impaired short-term but normal long-term object recognition memory.

PubMed

Palmer, Daniel; Creighton, Samantha; Prado, Vania F; Prado, Marco A M; Choleris, Elena; Winters, Boyer D

2016-09-15

Substantial evidence implicates Acetylcholine (ACh) in the acquisition of object memories. While most research has focused on the role of the cholinergic basal forebrain and its cortical targets, there are additional cholinergic networks that may contribute to object recognition. The striatum contains an independent cholinergic network comprised of interneurons. In the current study, we investigated the role of this cholinergic signalling in object recognition using mice deficient for Vesicular Acetylcholine Transporter (VAChT) within interneurons of the striatum. We tested whether these striatal VAChT(D2-Cre-flox/flox) mice would display normal short-term (5 or 15min retention delay) and long-term (3h retention delay) object recognition memory. In a home cage object recognition task, male and female VAChT(D2-Cre-flox/flox) mice were impaired selectively with a 15min retention delay. When tested on an object location task, VAChT(D2-Cre-flox/flox) mice displayed intact spatial memory. Finally, when object recognition was tested in a Y-shaped apparatus, designed to minimize the influence of spatial and contextual cues, only females displayed impaired recognition with a 5min retention delay, but when males were challenged with a 15min retention delay, they were also impaired; neither males nor females were impaired with the 3h delay. The pattern of results suggests that striatal cholinergic transmission plays a role in the short-term memory for object features, but not spatial location. Copyright © 2016 Elsevier B.V. All rights reserved.

41 CFR 101-27.304-2 - Factors affecting the economic retention limit.

Code of Federal Regulations, 2010 CFR

2010-07-01

... economic retention limit. 101-27.304-2 Section 101-27.304-2 Public Contracts and Property Management... economic retention limit. (a) The economic retention limit may be increased where: (1) The item is of... economic retention time limit; or (2) Costs incident to holding an additional quantity are insignificant...

41 CFR 101-27.304-2 - Factors affecting the economic retention limit.

Code of Federal Regulations, 2011 CFR

2011-07-01

... economic retention limit. 101-27.304-2 Section 101-27.304-2 Public Contracts and Property Management... economic retention limit. (a) The economic retention limit may be increased where: (1) The item is of... economic retention time limit; or (2) Costs incident to holding an additional quantity are insignificant...

41 CFR 101-27.304-2 - Factors affecting the economic retention limit.

Code of Federal Regulations, 2013 CFR

2013-07-01

... economic retention limit. 101-27.304-2 Section 101-27.304-2 Public Contracts and Property Management... economic retention limit. (a) The economic retention limit may be increased where: (1) The item is of... economic retention time limit; or (2) Costs incident to holding an additional quantity are insignificant...

41 CFR 101-27.304-2 - Factors affecting the economic retention limit.

Code of Federal Regulations, 2012 CFR

2012-07-01

... economic retention limit. 101-27.304-2 Section 101-27.304-2 Public Contracts and Property Management... economic retention limit. (a) The economic retention limit may be increased where: (1) The item is of... economic retention time limit; or (2) Costs incident to holding an additional quantity are insignificant...

41 CFR 101-27.304-2 - Factors affecting the economic retention limit.

Code of Federal Regulations, 2014 CFR

2014-07-01

... economic retention limit. 101-27.304-2 Section 101-27.304-2 Public Contracts and Property Management... economic retention limit. (a) The economic retention limit may be increased where: (1) The item is of... economic retention time limit; or (2) Costs incident to holding an additional quantity are insignificant...

Home healthcare nurse retention and patient outcome model: discussion and model development.

PubMed

Ellenbecker, Carol Hall; Cushman, Margaret

2012-08-01

This paper discusses additions to an empirically tested model of home healthcare nurse retention. An argument is made that the variables of shared decision-making and organizational commitment be added to the model based on the authors' previous research and additional evidence from the literature. Previous research testing the home healthcare nurse retention model established empirical relationships between nurse, agency, and area characteristics to nurse job satisfaction, intent to stay, and retention. Unexplained model variance prompted a new literature search to augment understanding of nurse retention and patient and agency outcomes. Data come from the authors' previous research, and a literature search from 1990 to 2011 on the topics organizational commitment, shared decision-making, nurse retention, patient outcomes and agency performance. The literature provides a rationale for the additional variables of shared decision-making and affective and continuous organizational commitment, linking these variables to nurse job satisfaction, nurse intent to stay, nurse retention and patient outcomes and agency performance. Implications for nursing.  The new variables in the model suggest that all agencies, even those not struggling to retain nurses, should develop interventions to enhance nurse job satisfaction to assure quality patient outcomes. The new nurse retention and patient outcome model increases our understanding of nurse retention. An understanding of the relationship among these variables will guide future research and the development of interventions to create and maintain nursing work environments that contribute to nurse affective agency commitment, nurse retention and quality of patient outcomes. © 2011 Blackwell Publishing Ltd.

The effect of modeled absolute timing variability and relative timing variability on observational learning.

PubMed

Grierson, Lawrence E M; Roberts, James W; Welsher, Arthur M

2017-05-01

There is much evidence to suggest that skill learning is enhanced by skill observation. Recent research on this phenomenon indicates a benefit of observing variable/erred demonstrations. In this study, we explore whether it is variability within the relative organization or absolute parameterization of a movement that facilitates skill learning through observation. To do so, participants were randomly allocated into groups that observed a model with no variability, absolute timing variability, relative timing variability, or variability in both absolute and relative timing. All participants performed a four-segment movement pattern with specific absolute and relative timing goals prior to and following the observational intervention, as well as in a 24h retention test and transfers tests that featured new relative and absolute timing goals. Absolute timing error indicated that all groups initially acquired the absolute timing, maintained their performance at 24h retention, and exhibited performance deterioration in both transfer tests. Relative timing error revealed that the observation of no variability and relative timing variability produced greater performance at the post-test, 24h retention and relative timing transfer tests, but for the no variability group, deteriorated at absolute timing transfer test. The results suggest that the learning of absolute timing following observation unfolds irrespective of model variability. However, the learning of relative timing benefits from holding the absolute features constant, while the observation of no variability partially fails in transfer. We suggest learning by observing no variability and variable/erred models unfolds via similar neural mechanisms, although the latter benefits from the additional coding of information pertaining to movements that require a correction. Copyright © 2017 Elsevier B.V. All rights reserved.

[Effect of conservation tillage on weeds in a rotation system on the Loess Plateau of eastern Gansu, Northwest China].

PubMed

Zhao, Yu-xin; Lu, Jiao-yun; Yang, Hui-min

2015-04-01

A field study was conducted to investigate the influences of no-tillage, stubble retention and crop type on weed density, species composition and community feature in a rotation system (winter wheat-common vetch-maize) established 12 years ago on the Loess Plateau of eastern Gansu. This study showed that the weed species composition, density and community feature varied with the change of crop phases. No-tillage practice increased the weed density at maize phase, while rotation with common vetch decreased the density in the no-tillage field. Stubble retention reduced the weed density under maize phase and the lowest density was observed in the no-tillage plus stubble retention field. No-tillage practice significantly increased the weed species diversity under winter wheat phase and decreased the diversity under common vetch phase. At maize phase, a greater species diversity index was observed in the no-tillage field. These results suggested that no-tillage practice and stubble retention possibly suppress specific weeds with the presence of some crops and crop rotation is a vital way to controlling weeds in a farming system.

Automatic grading of appearance retention of carpets using intensity and range images

NASA Astrophysics Data System (ADS)

Orjuela Vargas, Sergio Alejandro; Ortiz-Jaramillo, Benhur; Vansteenkiste, Ewout; Rooms, Filip; De Meulemeester, Simon; de Keyser, Robain; Van Langenhove, Lieva; Philips, Wilfried

2012-04-01

Textiles are mainly used for decoration and protection. In both cases, their original appearance and its retention are important factors for customers. Therefore, evaluation of appearance parameters are critical for quality assurance purposes, during and after manufacturing, to determine the lifetime and/or beauty of textile products. In particular, appearance retention of textile products is commonly certified with grades, which are currently assigned by human experts. However, manufacturers would prefer a more objective system. We present an objective system for grading appearance retention, particularly, for textile floor coverings. Changes in appearance are quantified by using linear regression models on texture features extracted from intensity and range images. Range images are obtained by our own laser scanner, reconstructing the carpet surface using two methods that have been previously presented. We extract texture features using a variant of the local binary pattern technique based on detecting those patterns whose frequencies are related to the appearance retention grades. We test models for eight types of carpets. Results show that the proposed approach describes the degree of wear with a precision within the range allowed to human inspectors by international standards. The methodology followed in this experiment has been designed to be general for evaluating global deviation of texture in other types of textiles, as well as other surface materials.

Application of perfluorinated acids as ion-pairing reagents for reversed-phase chromatography and retention-hydrophobicity relationships studies of selected beta-blockers.

PubMed

Flieger, J

2010-01-22

The addition of the homologous series of perfluorinated acids-trifluoroacetic acid (TFAA), pentafluoropropionic acid (PFPA), heptafluorobutyric acid (HFBA) to mobile phases for reversed-phase high-performance liquid chromatography (RP-HPLC) of beta-blockers was tested. Acidic modifiers were responsible for acidification of mobile phase (pH 3) ensuring the protonation of the beta-blockers and further ion pairs creation. The effect of the type and concentration of mobile phase additives on retention parameters, the efficiency of the peaks, their symmetry and separation selectivity of the beta-blockers mixture were all studied. It appeared that at increasing acid concentration, the retention factor, for all compounds investigated, increased to varying degrees. It should be stressed that the presence of acids more significantly affected the retention of the most hydrophobic beta-blockers. Differences in hydrophobicity of drugs can be maximized through variation of the hydrophobicity of additives. Thus, the relative increase in the retention depends on either concentration and hydrophobicity of the anionic mobile phase additive or hydrophobicity of analytes. According to QSRR (quantitative structure retention relationship) methodology, chromatographic lipophilicity parameters: isocratic log k and log k(w) values (extrapolated retention to pure water) were correlated with the molecular (log P(o/w)) and apparent (log P(app)) octanol-water partition coefficients obtained experimentally by countercurrent chromatography (CCC) or predicted by Pallas software. The obtained, satisfactory retention-hydrophobicity correlations indicate that, in the case of the basic drugs examined in RP-HPLC systems modified with perfluorinated acids, the retention is mainly governed by their hydrophobicity. Copyright 2009 Elsevier B.V. All rights reserved.

Evaluation of two polyimides and of an improved liner retention design for self-lubricating bushings

NASA Technical Reports Server (NTRS)

Sliney, H. E.

1984-01-01

Two different polyimide polymers were studied and the effectiveness of a design feature to improve retention of the self lubricating composite liners under high load was evaluated. The basic bearing design consisted of a molded layer of chopped graphite-fiber-reinforced-polyimide (GFRP) composite bonded to the bore of a steel bushing. The friction, wear, and load carrying ability of the bushings were determined in oscillating tests at 25, 260 and 315 C at radial unit loads up to 260 MPa. Friction coefficients were typically 0.15 to 0.25. Bushings with liners containing a new partially fluorinated polymer were functional, but had a lower load capacity and higher wear rate than those containing a more conventional, high temperature polyimide. The liner retention design feature reduced the tendency of the liners to crack and work out of the contact zone under high oscillating loads.

Feasibility of dialectical behavior therapy with suicidal and self-harming adolescents with multi-problems: training, adherence, and retention.

PubMed

Tørmoen, A J; Grøholt, B; Haga, E; Brager-Larsen, A; Miller, A; Walby, F; Stanley, B; Mehlum, L

2014-01-01

We evaluated the feasibility of DBT training, adherence, and retention preparing for a randomized controlled trial of Dialectical Behavior Therapy (DBT) adapted for Norwegian adolescents engaging in self-harming behavior and diagnosed with features of borderline personality disorder. Therapists were intensively trained and evaluated for adherence. Adherence scores, treatment retention, and present and previous self-harm were assessed. Twenty-seven patients were included (mean age 15.7 years), all of them with recent self-harming behaviors and at least 3 features of Borderline Personality Disorder. Therapists were adherent and 21 (78%) patients completed the whole treatment. Three subjects reported self-harm at the end of treatment, and urges to self-harm decreased. At follow up, 7 of 10 subjects reported no self-harm. DBT was found to be well accepted and feasible. Randomized controlled trials are required to test the effectiveness of DBT for adolescents.

Mechanism of molecular recognition on molecular imprinted monolith by capillary electrochromatography.

PubMed

Liu, Zhao-Sheng; Xu, Yan-Li; Yan, Chao; Gao, Ru-Yu

2005-09-16

The recognition mechanism of molecularly imprinted polymer (MIP) in capillary electrochromatography (CEC) is complicated since it possesses a hybrid process, which comprises the features of chromatographic retention, electrophoretic migration and molecular imprinting. For an understanding of the molecular recognition of MIP in CEC, a monolithic MIP in a capillary with 1,1'-binaphthyl-2,2'-diamine (BNA) imprinting was prepared by in situ copolymerization of imprinted molecule, methacrylic acid and ethylene glycol dimethacrylate in porogenic solvent, a mixture of toluene-isooctane. Strong recognition ability and high column performance (theory plates was 43,000 plates/m) of BNA were achieved on this monolithic MIP in CEC mode. In addition, BNA and its structural analogue, 1,1'-bi-2, 2'-naphthol, differing in functional groups, were used as model compounds to study imprinting effect on the resultant BNA-imprinted monolithic column, a reference column without imprinting of BNA and a open capillary. The effects of organic modifier concentration, pH value of buffer, salt concentration of buffer and column temperature on the retention and recognition of two compounds were investigated. The results showed that the molecular recognition on MIP monolith in CEC mode mainly derived from imprinting cavities on BNA-imprinted polymer other than chromatographic retention and electrophoretic migration.

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 17 2014-07-01 2014-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 17 2013-07-01 2013-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

40 CFR 80.1348 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 17 2012-07-01 2012-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Sampling, Testing and Retention Requirements § 80.1348 What gasoline sample retention requirements...

Visualization of LC-MS/MS proteomics data in MaxQuant.

PubMed

Tyanova, Stefka; Temu, Tikira; Carlson, Arthur; Sinitcyn, Pavel; Mann, Matthias; Cox, Juergen

2015-04-01

Modern software platforms enable the analysis of shotgun proteomics data in an automated fashion resulting in high quality identification and quantification results. Additional understanding of the underlying data can be gained with the help of advanced visualization tools that allow for easy navigation through large LC-MS/MS datasets potentially consisting of terabytes of raw data. The updated MaxQuant version has a map navigation component that steers the users through mass and retention time-dependent mass spectrometric signals. It can be used to monitor a peptide feature used in label-free quantification over many LC-MS runs and visualize it with advanced 3D graphic models. An expert annotation system aids the interpretation of the MS/MS spectra used for the identification of these peptide features. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Sleep on Word Pair Memory in Children - Separating Item and Source Memory Aspects.

PubMed

Wang, Jing-Yi; Weber, Frederik D; Zinke, Katharina; Noack, Hannes; Born, Jan

2017-01-01

Word paired-associate learning is a well-established task to demonstrate sleep-dependent memory consolidation in adults as well as children. Sleep has also been proposed to benefit episodic features of memory, i.e., a memory for an event (item) bound into the spatiotemporal context it has been experienced in (source). We aimed to explore if sleep enhances word pair memory in children by strengthening the episodic features of the memory, in particular. Sixty-one children (8-12 years) studied two lists of word pairs with 1 h in between. Retrieval testing comprised cued recall of the target word of each word pair (item memory) and recalling in which list the word pair had appeared in (source memory). Retrieval was tested either after 1 h (short retention interval) or after 11 h, with this long retention interval covering either nocturnal sleep or daytime wakefulness. Compared with the wake interval, sleep enhanced separate recall of both word pairs and the lists per se , while recall of the combination of the word pair and the list it had appeared in remained unaffected by sleep. An additional comparison with adult controls ( n = 37) suggested that item-source bound memory (combined recall of word pair and list) is generally diminished in children. Our results argue against the view that the sleep-induced enhancement in paired-associate learning in children is a consequence of sleep specifically enhancing the episodic features of the memory representation. On the contrary, sleep in children might strengthen item and source representations in isolation, while leaving the episodic memory representations (item-source binding) unaffected.

Brain Substrates of Learning and Retention in Mild Cognitive Impairment Diagnosis and Progression to Alzheimer's Disease

ERIC Educational Resources Information Center

Chang, Yu-Ling; Bondi, Mark W.; Fennema-Notestine, Christine; McEvoy, Linda K.; Hagler, Donald J., Jr.; Jacobson, Mark W.; Dale, Anders M.

2010-01-01

Understanding the underlying qualitative features of memory deficits in mild cognitive impairment (MCI) can provide critical information for early detection of Alzheimer's disease (AD). This study sought to investigate the utility of both learning and retention measures in (a) the diagnosis of MCI, (b) predicting progression to AD, and (c)…

Assessing Potential Additional PFAS Retention Processes in the Subsurface

NASA Astrophysics Data System (ADS)

Brusseau, M. L.

2017-12-01

Understanding the transport and fate of per- and poly-fluorinated alkyl substances (PFASs) in the subsurface is critical for accurate risk assessments and design of effective remedial actions. Current conceptual and mathematical models are based on an assumption that solid-phase adsorption is the sole source of retention for PFASs. However, additional retention processes may be relevant for PFAS compounds in vadose-zone systems and in source zones that contain trapped immiscible organic liquids. These include adsorption at the air-water interface, partitioning to the soil atmosphere, adsorption at the NAPL-water interface, and absorption by NAPL. A multi-process retention model is proposed to account for these potential additional sources of PFAS retardation. An initial assessment of the relative magnitudes and significance of these retention processes was conducted for three representative PFASs, perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and 8:2 fluorotelomer alcohol (FTOH). Data collected from the literature were used to determine measured or estimated values for the relevant distribution coefficients, which were in turn used to calculate retardation factors for a representative porous medium. Adsorption at the air-water interface was shown to be a primary source of retention for PFOA and PFOS, contributing approximately 80% of total retardation. Adsorption to NAPL-water interfaces and absorption by bulk NAPL were also shown to be significant sources of retention for PFOS and PFOA. The latter process was the predominant source of retention for 8:2 FTOH, contributing 98% of total retardation. These results indicate that we may anticipate significant retention of PFASs by these additional processes. In such cases, retardation of PFASs in source areas may be significantly greater than what is typically estimated based on the standard assumption of solid-phase adsorption as the sole retention mechanism. This has significant ramifications for accurate determination of the migration potential and magnitude of mass flux to groundwater, as well as for calculations of contaminant mass residing in source zones.

Comparison of capillary electrophoresis-mass spectrometry and hydrophilic interaction chromatography-mass spectrometry for anionic metabolic profiling of urine.

PubMed

Kok, Miranda G M; Somsen, Govert W; de Jong, Gerhardus J

2015-01-01

In order to assess the utility of a recently developed capillary electrophoresis-mass spectrometry (CE-MS) method for the study of anionic metabolites in urine, a comparison was made with hydrophilic interaction chromatography-MS (HILIC-MS) using negative electrospray ionization. After optimization of the HILIC conditions, a gradient employing 10mM ammonium acetate (pH 6.8) in acetonitrile-water (5 min 90% acetonitrile followed by 90%-50% acetonitrile in 10 min) was selected, providing baseline separation of five representative anionic test metabolites. Relative standard deviations (RSDs) for HILIC retention times and peak areas were below 0.2% and 7.7%, respectively, and detection limits were in the range 0.04-2.21 μM. Metabolites in rat urine could also be analysed in a reproducible way with retention time and peak area RSDs below 0.6% and 13.6%, respectively. The CE-MS and HILIC-MS methods were compared in terms of reproducibility, sensitivity, selectivity and coverage of the anionic urinary metabolome. In general, peak area RSDs were similar whereas HILIC-MS yielded better retention-time repeatability and up to 80 times lower detection limits (expressed in injected concentration) for test metabolites as compared to CE-MS. Rat urine analysis by HILIC-MS provided detection of 1360 molecular features compared to 347 molecular features revealed with CE-MS. Of these, a number of 144 molecular features were found with both HILIC-MS and CE-MS, which showed on average 10 times higher peak areas in HILIC-MS. The HILIC retention and CE migration times of the common features were clearly not correlated. The HILIC and CE behavior of the test metabolites and 16 putatively identified common features were evaluated involving their physicochemical properties, indicating a markedly different separation selectivity, and thus significant degree of orthogonality of HILIC and CE. Copyright © 2014 Elsevier B.V. All rights reserved.

Varying rotation lengths in northern production forests: Implications for habitats provided by retention and production trees.

PubMed

Felton, Adam; Sonesson, Johan; Nilsson, Urban; Lämås, Tomas; Lundmark, Tomas; Nordin, Annika; Ranius, Thomas; Roberge, Jean-Michel

2017-04-01

Because of the limited spatial extent and comprehensiveness of protected areas, an increasing emphasis is being placed on conserving habitats which promote biodiversity within production forest. For this reason, alternative silvicultural programs need to be evaluated with respect to their implications for forest biodiversity, especially if these programs are likely to be adopted. Here we simulated the effect of varied rotation length and associated thinning regimes on habitat availability in Scots pine and Norway spruce production forests, with high and low productivity. Shorter rotation lengths reduced the contribution made by production trees (trees grown for industrial use) to the availability of key habitat features, while concurrently increasing the contribution from retention trees. The contribution of production trees to habitat features was larger for high productivity sites, than for low productivity sites. We conclude that shortened rotation lengths result in losses of the availability of habitat features that are key for biodiversity conservation and that increased retention practices may only partially compensate for this. Ensuring that conservation efforts better reflect the inherent variation in stand rotation lengths would help improve the maintenance of key forest habitats in production forests.

Stabilized tin-oxide-based oxidation/reduction catalysts

NASA Technical Reports Server (NTRS)

Watkins, Anthony Neal (Inventor); Oglesby, Donald M. (Inventor); Gulati, Suresh T. (Inventor); Summers, Jerry C. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Leighty, Bradley D. (Inventor); Jordan, Jeffrey D. (Inventor); Schryer, Jacqueline L. (Inventor)

2008-01-01

The invention described herein involves a novel approach to the production of oxidation/reduction catalytic systems. The present invention serves to stabilize the tin oxide reducible metal-oxide coating by co-incorporating at least another metal-oxide species, such as zirconium. In one embodiment, a third metal-oxide species is incorporated, selected from the group consisting of cerium, lanthanum, hafnium, and ruthenium. The incorporation of the additional metal oxide components serves to stabilize the active tin-oxide layer in the catalytic process during high-temperature operation in a reducing environment (e.g., automobile exhaust). Moreover, the additional metal oxides are active components due to their oxygen-retention capabilities. Together, these features provide a mechanism to extend the range of operation of the tin-oxide-based catalyst system for automotive applications, while maintaining the existing advantages.

49 CFR 229.215 - Retention and inspection of designs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Crashworthiness... crashworthiness features required by this subpart. These records must be retained for the lesser period of: (1... this subpart shall retain all records of repair or modification to crashworthiness features required by...

49 CFR 229.215 - Retention and inspection of designs.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Crashworthiness... crashworthiness features required by this subpart. These records must be retained for the lesser period of: (1... this subpart shall retain all records of repair or modification to crashworthiness features required by...

49 CFR 229.215 - Retention and inspection of designs.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Crashworthiness... crashworthiness features required by this subpart. These records must be retained for the lesser period of: (1... this subpart shall retain all records of repair or modification to crashworthiness features required by...

49 CFR 229.215 - Retention and inspection of designs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Crashworthiness... crashworthiness features required by this subpart. These records must be retained for the lesser period of: (1... this subpart shall retain all records of repair or modification to crashworthiness features required by...

49 CFR 229.215 - Retention and inspection of designs.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Crashworthiness... crashworthiness features required by this subpart. These records must be retained for the lesser period of: (1... this subpart shall retain all records of repair or modification to crashworthiness features required by...

Enhancing Long-Term Retention of New Vocabulary Using Visual Images.

ERIC Educational Resources Information Center

Igelsrud, Karen

A practicum used a new learning tool to enhance long-term retention of new vocabulary. Sixteen seventh-graders in Language Arts, who had a long-term retention mean score of approximately 40% of newly learned vocabulary, increased their long-term retention of new vocabulary by 25% (a new mean of 65% of new vocabulary). Additional objectives…

Assessing the potential contributions of additional retention processes to PFAS retardation in the subsurface.

PubMed

Brusseau, Mark L

2018-02-01

A comprehensive understanding of the transport and fate of per- and poly-fluoroalkyl substances (PFAS) in the subsurface is critical for accurate risk assessments and design of effective remedial actions. A multi-process retention model is proposed to account for potential additional sources of retardation for PFAS transport in source zones. These include partitioning to the soil atmosphere, adsorption at air-water interfaces, partitioning to trapped organic liquids (NAPL), and adsorption at NAPL-water interfaces. An initial assessment of the relative magnitudes and significance of these retention processes was conducted for two PFAS of primary concern, perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), and an example precursor (fluorotelomer alcohol, FTOH). The illustrative evaluation was conducted using measured porous-medium properties representative of a sandy vadose-zone soil. Data collected from the literature were used to determine measured or estimated values for the relevant distribution coefficients, which were in turn used to calculate retardation factors for the model system. The results showed that adsorption at the air-water interface was a primary source of retention for both PFOA and PFOS, contributing approximately 50% of total retention for the conditions employed. Adsorption to NAPL-water interfaces and partitioning to bulk NAPL were also shown to be significant sources of retention. NAPL partitioning was the predominant source of retention for FTOH, contributing ~98% of total retention. These results indicate that these additional processes may be, in some cases, significant sources of retention for subsurface transport of PFAS. The specific magnitudes and significance of the individual retention processes will depend upon the properties and conditions of the specific system of interest (e.g., PFAS constituent and concentration, porous medium, aqueous chemistry, fluid saturations, co-contaminants). In cases wherein these additional retention processes are significant, retardation of PFAS in source areas would likely be greater than what is typically estimated based on the standard assumption of solid-phase adsorption as the sole retention mechanism. This has significant ramifications for accurate determination of the migration potential and magnitude of mass flux to groundwater, as well as for calculations of contaminant mass residing in source zones. Both of which have critical implications for human-health risk assessments. Copyright © 2017 Elsevier B.V. All rights reserved.

Acute urinary retention due to benign inflammatory nervous diseases.

PubMed

Sakakibara, Ryuji; Yamanishi, Tomonori; Uchiyama, Tomoyuki; Hattori, Takamichi

2006-08-01

Both neurologists and urologists might encounter patients with acute urinary retention due to benign inflammatory nervous diseases. Based on the mechanism of urinary retention, these disorders can be divided into two subgroups: disorders of the peripheral nervous system (e.g., sacral herpes) or the central nervous system (e.g., meningitis-retention syndrome [MRS]). Laboratory abnormalities include increased herpes virus titers in sacral herpes, and increased myelin basic protein in the cerebrospinal fluid (CSF) in some cases with MRS. Urodynamic abnormality in both conditions is detrusor areflexia; the putative mechanism of it is direct involvement of the pelvic nerves in sacral herpes; and acute spinal shock in MRS. There are few cases with CSF abnormality alone. Although these cases have a benign course, management of the acute urinary retention is necessary to avoid bladder injury due to overdistension. Clinical features of sacral herpes or MRS differ markedly from those of the original "Elsberg syndrome" cases.

Children's Retrieval of Classroom Materials: A Test of Conjoint Retention.

ERIC Educational Resources Information Center

Stader, Ellen D.; And Others

A total of 90 fifth- and sixth-grade students studied a map of the fictitious island while twice listening to a 1,100-word prose passage describing it. The description included 16 nouns that had been chosen as map features. Map features were identified by labels and icons. Afterwards, students were given a cued recall test with 16 feature-related…

Effect of air-abrasion on the retention of zirconia ceramic crowns luted with different cements before and after artificial aging.

PubMed

Shahin, Ramez; Kern, Matthias

2010-09-01

The purpose of this in vitro study was to evaluate the effect of intaglio surface air-abrasion on the retention of CAD/CAM produced zirconia ceramic crowns cemented with three different types of cement. In addition the influence of artificial aging in masticatory simulator and thermocycling was tested. Extracted human premolars were prepared for all-ceramic crowns (12 degrees taper, 3 mm axial length). CAD/CAM zirconia crowns were manufactured. Half of the crowns were air-abraded with 50 microm alumina particles at 0.25 MPa, the rest was left as machined. The crowns were luted with zinc phosphate cement (Hoffmann), glass ionomer cement (Ketac Cem), or composite resin (Panavia 21), subgroups were either stored for 3 days in 37 degrees water bath or stored for 150 days in 37 degrees water bath, with additional 37,500 thermal cycles (5-55 degrees) and 300,000 cycles dynamic loading with 5 kg in a masticatory simulator. Then crown retention was measured in tension at a crosshead speed of 2 mm/min using a universal testing machine. Statistical analysis was performed with three-way ANOVA. Mean retention values were ranged from 2.8 to 7.1 MPa after 3 days and from 1.6 to 6.1 MPa after artificial aging. Air-abrasion significantly increased crown retention (p<0.001), while artificial aging decreased retention (p=0.017). In addition, the luting material had a significant influence on retention (p<0.001) with the adhesive luting resin providing the highest retention. The use of phosphate monomer containing composite resin on air-abraded zirconia ceramic can be recommended as most retentive luting method. Copyright 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

An economic assessment of local farm multi-purpose surface water retention systems in a Canadian Prairie setting

NASA Astrophysics Data System (ADS)

Berry, Pamela; Yassin, Fuad; Belcher, Kenneth; Lindenschmidt, Karl-Erich

2017-12-01

There is a need to explore more sustainable approaches to water management on the Canadian Prairies. Retention pond installation schemes designed to capture surface water may be a viable option that would reduce water stress during drought periods by providing water for irrigation. The retention systems would serve to capture excess spring runoff and extreme rainfall events, reducing flood potential downstream. Additionally, retention ponds may be used for biomass production and nutrient retention. The purpose of this research was to investigate the economic viability of adopting local farm surface water retention systems as a strategic water management strategy. A retention pond was analyzed using a dynamic simulation model to predict its storage capacity, installation and upkeep cost, and economic advantage to farmers when used for irrigation. While irrigation application increased crop revenue, the cost of irrigation and reservoir infrastructure and installation costs were too high for the farmer to experience a positive net revenue. Farmers who harvest cattails from retention systems for biomass and available carbon offset credits can gain 642.70/hectare of harvestable cattail/year. Cattail harvest also removes phosphorus and nitrogen, providing a monetized impact of 7014/hectare of harvestable cattail/year. The removal of phosphorus, nitrogen, carbon, and avoided flooding damages of the retention basin itself provide an additional 17,730-18,470/hectare of retention system/year. The recommended use of retention systems is for avoided flood damages, nutrient retention, and biomass production. The revenue gained from these functions can support farmers wanting to invest in irrigation while providing economic and environmental benefits to the region.

Carcass addition does not enhance juvenile salmonid biomass, growth, or retention in six Northwestern California streams.

Treesearch

Bret Harvey; Margaret A. Wilzbach

2010-01-01

Fisheries managers commonly consider the addition of salmon carcasses when seeking to enhance salmonid populations. However, the range of environmental conditions under which the technique is effective remains poorly defined. We addressed this issue by measuring the effects of wintertime addition of salmon carcasses on the biomass, growth, and retention of juvenile...

Separation of alkylphenols by normal-phase and reversed-phase high-performance liquid chromatography

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

Schabron, J.F.; Hurtubise, R.J.; Silver, H.F.

1978-11-01

Empirical correlation factors were developed which relate log k' values for alkylphenols, the naphthols, and two phenylphenols to structural features. Both normal-phase and reversed-phase chromatographic systems were studied. The stationary phases employed in the normal-phase work were ..mu..-Bondapak CN, ..mu..-Bondapak NH/sub 2/, and ..mu..-Porasil. The structural features which affect retention in the normal-phase chromatographic systems are the number of ortho substituents, the number of aliphatic carbons, and the number of aromatic rings. The stationary phases employed in the reversed-phase work were ..mu..-Bondapak C/sub 18/ and ..mu..-Bondapak CN. The structural features which affect retention in the reversed-phase chromatographic systems are themore » number of aliphatic carbons and the number of aromatic double bonds. On ..mu..-Bondapak C/sub 18/, the presence or absence of a nonaromatic ring is of added importance.« less

Registered nurse retention strategies in nursing homes: a two-factor perspective.

PubMed

Hunt, Selina R; Probst, Janice C; Haddock, Kathlyn S; Moran, Robert; Baker, Samuel L; Anderson, Ruth A; Corazzini, Kirsten

2012-01-01

As the American population ages and the proportion of individuals over the age of 65 expands, the demand for high-quality nursing home care will increase. However, nursing workforce instability threatens care quality and sustainability in this sector. Despite increasing attention to nursing home staff turnover, far less is known about registered nurse (RN) retention. In this study, the relationships between retention strategies, employee benefits, features of the practice environment, and RN retention were explored. Further, the utility of Herzberg's two-factor theory of motivation as a framework for nursing home retention studies was evaluated. This study was a secondary analysis of the nationally representative 2004 National Nursing Home Survey. The final sample of 1,174 participating nursing homes were either certified by Medicare or Medicaid or licensed by state agencies. We used a weighted multinomial logistic regression using an incremental approach to model the relationships. Although most nursing homes offered some combination of retention programs, the majority of strategies did not have a significant association with the level of RN retention reported by facilities. Director of nursing tenure and other extrinsic factors had the strongest association with RN retention in adjusted analyses. To improve RN retention, organizations may benefit greatly from stabilizing nursing home leadership, especially the director of nursing position. Second, managers of facilities with poor retention may consider adding career ladders for advancement, awarding attendance, and improving employee benefits. As a behavioral outcome of motivation and satisfaction, retention was not explained as expected using Herzberg's two-factor theory.

700 F hybrid capacitors cells composed of activated carbon and Li4Ti5O12 microspheres with ultra-long cycle life

NASA Astrophysics Data System (ADS)

Ruan, Dianbo; Kim, Myeong-Seong; Yang, Bin; Qin, Jun; Kim, Kwang-Bum; Lee, Sang-Hyun; Liu, Qiuxiang; Tan, Lei; Qiao, Zhijun

2017-10-01

To address the large-scale application demands of high energy density, high power density, and long cycle lifetime, 700-F hybrid capacitor pouch cells have been prepared, comprising ∼240-μm-thick activated carbon cathodes, and ∼60-μm-thick Li4Ti5O12 anodes. Microspherical Li4Ti5O12 (M-LTO) synthesized by spray-drying features 200-400 nm primary particles and interconnected nanopore structures. M-LTO half-cells exhibits high specific capacities (175 mAhh g-1), good rate capabilities (148 mAhh g-1 at 20 C), and ultra-long cycling stabilities (90% specific capacity retention after 10,000 cycles). In addition, the obtained hybrid capacitors comprising activated carbon (AC) and M-LTO shows excellent cell performances, achieving a maximum energy density of 51.65 Wh kg-1, a maximum power density of 2466 W kg-1, and ∼92% capacitance retention after 10,000 cycles, thus meeting the demands for large-scale applications such as trolleybuses.

Methodology for the effective stabilization of tin-oxide-based oxidation/reduction catalysts

NASA Technical Reports Server (NTRS)

Jordan, Jeffrey D. (Inventor); Schryer, David R. (Inventor); Leighty, Bradley D. (Inventor); Watkins, Anthony N. (Inventor); Summers, Jerry C. (Inventor); Davis, Patricia P. (Inventor); Oglesby, Donald M. (Inventor); Schryer, Jacqueline L. (Inventor); Gulati, Suresh T. (Inventor)

2011-01-01

The invention described herein involves a novel approach to the production of oxidation/reduction catalytic systems. The present invention serves to stabilize the tin oxide reducible metal-oxide coating by co-incorporating at least another metal-oxide species, such as zirconium. In one embodiment, a third metal-oxide species is incorporated, selected from the group consisting of cerium, lanthanum, hafnium, and ruthenium. The incorporation of the additional metal oxide components serves to stabilize the active tin-oxide layer in the catalytic process during high-temperature operation in a reducing environment (e.g., automobile exhaust). Moreover, the additional metal oxides are active components due to their oxygen-retention capabilities. Together, these features provide a mechanism to extend the range of operation of the tin-oxide-based catalyst system for automotive applications, while maintaining the existing advantages.

40 CFR 80.1631 - Gasoline, RBOB, and CBOB sample retention requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Gasoline, RBOB, and CBOB sample... (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur § 80.1631 Gasoline, RBOB, and CBOB sample retention requirements. (a) Sample retention requirements. Beginning...

Map Feature Content and Text Recall of Good and Poor Readers.

ERIC Educational Resources Information Center

Amlund, Jeanne T.; And Others

1985-01-01

Reports two experiments evaluating the effect of map feature content on text recall by subjects of varying reading skill levels. Finds that both experiments support the conjoint retention hypothesis, in which dual-coding of spatial and verbal information and their interaction in memory enhance recall. (MM)

5 CFR 430.208 - Rating performance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... only on the evaluation of actual job performance for the designated appraisal period. (2) An agency... limited to, assigning additional retention service credit under § 351.504 of this chapter. (5) Under the provisions of § 351.504(e) of this chapter, the number of years of additional retention service credit...

PR[superscript 2]EPS: Preparation, Recruitment, Retention and Excellence in the Physical Sciences, Including Engineering. A Report on the 2004, 2005 and 2006 Science Summer Camps

ERIC Educational Resources Information Center

Bachman, Nancy J.; Bischoff, Paul J.; Gallagher, Hugh; Labroo, Sunil; Schaumloffel, John C.

2008-01-01

Now in its fourth year, PR[superscript 2]EPS is a National Science Foundation funded initiative designed to recruit high school students to attend college majoring in the physical sciences, including engineering and secondary science education, and to help ensure their retention within the program until graduation. A central feature of the…

[Application of general retention time formula for gradient liquid chromatography in the studies of ladder-like gradient elution].

PubMed

Sun, Xiaoli; Hao, Weiqiang; Wang, Junde; Di, Bin; Chen, Qiang; Zhuang, Wei; Yu, Qiang; Zhang, Peipei

2013-08-01

By not explicitly specifying the type of solvent strength model, the features of ladder-like gradient elution were studied based on the general retention time formula that was derived in our previous work. For the case where the solute is eluted at like gradient, we derived the expression that connects the mobile phase composition (phiR), at which the solute is eluted from the column, with the gradient slope (B). It was shown that phiR will increase with the increase of B in this case. For the case where the solute is eluted at the last isocratic segment of the ladder-like gradient, it was proven that the retention time (tR) will correlate linearly with the reciprocal of the gradient slope (1/B) when the initial and final mobile phase compositions are set to be constant. In experiments, by taking biphenyl as the sample, the values of retention time in isocratic and gradient elution were measured on a C18 column by using a mixture of methanol and water as the mobile phase. The experimental values were found to be well consistent with the theoretical values that were calculated from the expressions. These expressions will be helpful to understand the features of the ladder-like gradient in practice.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, M.M.; Shoup, T.

1998-09-15

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, M.M.; Shoup, T.

1998-10-06

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, Mark M.; Shoup, Timothy

1998-09-15

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, Mark M.; Shoup, Timothy

1998-10-06

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 17 2013-07-01 2013-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 17 2012-07-01 2012-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 17 2014-07-01 2014-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

40 CFR 80.335 - What gasoline sample retention requirements apply to refiners and importers?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false What gasoline sample retention... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Sampling, Testing and Retention Requirements for Refiners and Importers § 80.335 What gasoline sample...

49 CFR 219.901 - Retention of alcohol testing records.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Retention of alcohol testing records. 219.901... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.901 Retention of alcohol testing records. (a) General requirement. In addition to the records required to be...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

49 CFR 219.903 - Retention of drug testing records.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Retention of drug testing records. 219.903 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CONTROL OF ALCOHOL AND DRUG USE Recordkeeping Requirements § 219.903 Retention of drug testing records. (a) General requirement. In addition to the records required to be kept...

Influence of high dose of phytase and an emulsifier on performance, apparent metabolisable energy and nitrogen retention in broilers fed on diets containing soy oil or tallow.

PubMed

Zaefarian, F; Romero, L F; Ravindran, V

2015-01-01

The effects of high dose of microbial phytase and an emulsifier on the performance, apparent metabolisable energy (AME) and nitrogen (N) retention in broilers fed on diets containing different fat sources were examined in a 5-week trial. Two fat sources (soy oil and tallow), two inclusion levels of E. coli phytase (500 or 1000 phytase units (FTU)/kg diet) and two inclusion levels of lysolecithin emulsifier (0 or 3.5 g/kg of diet) were evaluated in a 2 × 2 × 2 factorial arrangement of treatments. Throughout the 5-week trial, soy oil supplementation improved weight gain and feed per gain compared with tallow, but had no effect on feed intake. The high dose of phytase increased the weight gain and feed intake and lowered the feed per gain during d 1-21, but had no effect on performance parameters over the whole trial period. An effect of emulsifier was observed for feed intake during d 1-21 and over the whole trial period. Addition of emulsifier increased feed intake compared with diets without emulsifier. During weeks 1, 2, 3 and 5, birds fed on soy oil-based diets had higher nitrogen-corrected AME (AMEN) compared with those fed on tallow-based diets. During weeks 2, 3 and 5, the effect of phytase was significant for AMEN, with the high dose increasing the AMEN. During week 2, AMEN was increased with emulsifier addition. During weeks 1, 2, 3 and 5, birds fed on soy oil-based diets had higher fat retention compared with those fed on tallow-based diets. The high dose of phytase improved the retention of fat during week 5 and the addition of emulsifier resulted in higher fat retention during week 1. During weeks 2, 3 and 5, an interaction between fat source × phytase × emulsifier was observed for N retention. In soy oil-based diets, emulsifier plus 1000 FTU/kg phytase increased N retention compared with other groups, while in tallow-based diets, emulsifier addition increased N retention in diets with 500 FTU/kg, but not in 1000 FTU/kg diet. Overall, the present data suggest that the dietary fat source influenced performance, AMEN and fat retention in broiler chickens. There is opportunity to improve bird performance during d 1-21, AMEN and fat retention with higher doses of microbial phytase. Addition of the emulsifier increased the AMEN during week 2 and tract retention of fat during week 1, but this effect was not translated into improvements in performance.

A new retrospective, multi-evidence veterinary drug screening method using drift tube ion mobility mass spectrometry.

PubMed

Xu, Zhenzhen; Li, Jianzhong; Chen, Ailiang; Ma, Xin; Yang, Shuming

2018-05-03

The retrospectivity (the ability to retrospect to a previously unknown compound in raw data) is very meaningful for food safety and risk assessment when facing new emerging drugs. Accurate mass and retention time based screening may lead false positive and false negative results so new retrospective, reliable platform is desirable. Different concentration levels of standards with and without matrix were analyzed using ion mobility (IM)-quadrupole-time-of-flight (Q-TOF) for collecting retrospective accurate mass, retention time, drift time and tandem MS evidence for identification in a single experiment. The isomer separation ability of IM and the four-dimensional (4D) feature abundance quantification abilities were evaluated for veterinary drugs for the first time. The sensitivity of the IM-Q-TOF workflow was obviously higher than that of the traditional database searching algorithm [find by formula (FbF) function] for Q-TOF. In addition, the IM-Q-TOF workflow contained most of the results from FbF and removed the false positive results. Some isomers were separated by IM and the 4D feature abundance quantitation removed interference with similar accurate mass and showed good linearity. A new retrospective, multi-evidence platform was built for veterinary drug screening in a single experiment. The sensitivity was significantly improved and the data can be used for quantification. The platform showed its potential to be used for food safety and risk assessment. This article is protected by copyright. All rights reserved.

The potential of hybrid forward osmosis membrane bioreactor (FOMBR) processes in achieving high throughput treatment of municipal wastewater with enhanced phosphorus recovery.

PubMed

Qiu, Guanglei; Zhang, Sui; Srinivasa Raghavan, Divya Shankari; Das, Subhabrata; Ting, Yen-Peng

2016-11-15

Extensive research in recent years has explored numerous new features in the forward osmosis membrane bioreactor (FOMBR) process. However, there is an aspect, which is revolutionary but not yet been investigated. In FOMBR, FO membrane shows high rejection for a wide range of soluble contaminants. As a result, hydraulic retention time (HRT) does not correctly reflect the nominal retention of these dissolved contaminants in the bioreactor. This decoupling of contaminants retention time (CRT, i.e. the nominal retention of the dissolved contaminants) from HRT endows FOMBR a potential in significantly reducing the HRT for wastewater treatment. In this work, we report our results in this unexplored treatment potential. Using real municipal wastewater as feed, both a hybrid microfiltration-forward osmosis membrane bioreactor (MF-FOMBR) and a newly developed hybrid biofilm-forward osmosis membrane bioreactor (BF-FOMBR) achieved high removal of organic matter and nitrogen under HRT of down to 2.0 h, with significantly enhanced phosphorus recovery capacities. In the BF-FOMBR, the used of fixed bed biofilm not only obviated the need of additional solid/liquid separation (e.g. MF) to extract the side-stream for salt accumulation control and phosphorus recovery, but effectively quarantined the biomass from the FO membrane. The absence of MF in the side-stream further allowed suspended growth to be continuously removed from the system, which produced a selection pressure for the predominance of attached growth. As a result, a significant reduction in FO membrane fouling (by 24.7-54.5%) was achieved in the BF-FOMBR due to substantially reduced bacteria deposition and colonization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Incentives and Mailing Features on Online Health Program Enrollment

PubMed Central

Alexander, Gwen L.; Divine, George W.; Couper, Mick P.; McClure, Jennifer B.; Stopponi, Melanie A.; Fortman, Kristine K.; Tolsma, Dennis D.; Strecher, Victor J.; Johnson, Christine Cole

2008-01-01

Background With the growing use of Internet-based interventions, strategies are needed to encourage broader participation. This study examined the effects of combinations of monetary incentives and mailing characteristics on enrollment, retention, and cost effectiveness for an online health program. Methods In 2004, a recruitment letter was mailed to randomly selected Midwestern integrated health system members aged 21–65 and stratified by gender and race/ethnicity; recipients were randomly pre-assigned to one of 24 combinations of incentives and various mailing characteristics. Enrollment and 3-month retention rates were measured by completion of online surveys. Analysis, completed in 2005, compared enrollment and retention factors using t tests and chi-square tests. Multivariate logistic regression modeling assessed the probability of enrollment and retention. Results Of 12,289 subjects, 531 (4.3%) enrolled online, ranging from 1% to 11% by incentive combination. Highest enrollment occurred with unconditional incentives, and responses varied by gender. Retention rates ranged from 0% to 100%, with highest retention linked to higher-value incentives. The combination of a $2 bill prepaid incentive and the promise of $20 for retention (10% enrollment and 71% retention) was optimal, considering per-subject recruitment costs ($32 enrollment, $70 retention) and equivalent enrollment by gender and race/ethnicity. Conclusions Cash incentives improved enrollment in an online health program. Men and women responded differently to mailing characteristics and incentives. Including a small prepaid monetary incentive ($2 or $5) and revealing the higher promised-retention incentive was cost effective and boosted enrollment. PMID:18407004

A Guideline to Univariate Statistical Analysis for LC/MS-Based Untargeted Metabolomics-Derived Data

PubMed Central

Vinaixa, Maria; Samino, Sara; Saez, Isabel; Duran, Jordi; Guinovart, Joan J.; Yanes, Oscar

2012-01-01

Several metabolomic software programs provide methods for peak picking, retention time alignment and quantification of metabolite features in LC/MS-based metabolomics. Statistical analysis, however, is needed in order to discover those features significantly altered between samples. By comparing the retention time and MS/MS data of a model compound to that from the altered feature of interest in the research sample, metabolites can be then unequivocally identified. This paper reports on a comprehensive overview of a workflow for statistical analysis to rank relevant metabolite features that will be selected for further MS/MS experiments. We focus on univariate data analysis applied in parallel on all detected features. Characteristics and challenges of this analysis are discussed and illustrated using four different real LC/MS untargeted metabolomic datasets. We demonstrate the influence of considering or violating mathematical assumptions on which univariate statistical test rely, using high-dimensional LC/MS datasets. Issues in data analysis such as determination of sample size, analytical variation, assumption of normality and homocedasticity, or correction for multiple testing are discussed and illustrated in the context of our four untargeted LC/MS working examples. PMID:24957762

A Guideline to Univariate Statistical Analysis for LC/MS-Based Untargeted Metabolomics-Derived Data.

PubMed

Vinaixa, Maria; Samino, Sara; Saez, Isabel; Duran, Jordi; Guinovart, Joan J; Yanes, Oscar

2012-10-18

Several metabolomic software programs provide methods for peak picking, retention time alignment and quantification of metabolite features in LC/MS-based metabolomics. Statistical analysis, however, is needed in order to discover those features significantly altered between samples. By comparing the retention time and MS/MS data of a model compound to that from the altered feature of interest in the research sample, metabolites can be then unequivocally identified. This paper reports on a comprehensive overview of a workflow for statistical analysis to rank relevant metabolite features that will be selected for further MS/MS experiments. We focus on univariate data analysis applied in parallel on all detected features. Characteristics and challenges of this analysis are discussed and illustrated using four different real LC/MS untargeted metabolomic datasets. We demonstrate the influence of considering or violating mathematical assumptions on which univariate statistical test rely, using high-dimensional LC/MS datasets. Issues in data analysis such as determination of sample size, analytical variation, assumption of normality and homocedasticity, or correction for multiple testing are discussed and illustrated in the context of our four untargeted LC/MS working examples.

Oculomotor selection underlies feature retention in visual working memory.

PubMed

Hanning, Nina M; Jonikaitis, Donatas; Deubel, Heiner; Szinte, Martin

2016-02-01

Oculomotor selection, spatial task relevance, and visual working memory (WM) are described as three processes highly intertwined and sustained by similar cortical structures. However, because task-relevant locations always constitute potential saccade targets, no study so far has been able to distinguish between oculomotor selection and spatial task relevance. We designed an experiment that allowed us to dissociate in humans the contribution of task relevance, oculomotor selection, and oculomotor execution to the retention of feature representations in WM. We report that task relevance and oculomotor selection lead to dissociable effects on feature WM maintenance. In a first task, in which an object's location was encoded as a saccade target, its feature representations were successfully maintained in WM, whereas they declined at nonsaccade target locations. Likewise, we observed a similar WM benefit at the target of saccades that were prepared but never executed. In a second task, when an object's location was marked as task relevant but constituted a nonsaccade target (a location to avoid), feature representations maintained at that location did not benefit. Combined, our results demonstrate that oculomotor selection is consistently associated with WM, whereas task relevance is not. This provides evidence for an overlapping circuitry serving saccade target selection and feature-based WM that can be dissociated from processes encoding task-relevant locations. Copyright © 2016 the American Physiological Society.

Effects of inactivating individual cerebellar nuclei on the performance and retention of an operantly conditioned forelimb movement.

PubMed

Milak, M S; Shimansky, Y; Bracha, V; Bloedel, J R

1997-08-01

These experiments were designed to examine the effects of inactivating separately each of the major cerebellar nuclear regions in cats on the execution and retention of a previously learned, operantly conditioned volitional forelimb movement. The experiments test the postulates that the cerebellar nuclei, and particularly the interposed nuclei, contribute substantially to the spatial and temporal features of the interjoint coordination required to execute the task and that the engram necessary for the retention of this task is not located in any one of the cerebellar nuclei. All cats were trained to perform a task in which they were required to reach for and grasp a vertical bar at the sound of a tone and move the bar to a reward zone through a template consisting of two straight grooves in the shape of an inverted "L." After the task was learned, the effects of inactivating separately each nuclear region (the fastigial, interposed, and dentate nuclei) using muscimol microinjections were determined. Data were analyzed by quantifying several features of the movement's kinematics and by determining changes in the organization of the reaching component of the movement using an application of dimensionality analysis, an analysis that examines the correlation among the changes in joint angles and limb segment positions during the task. The retention of the previously learned task also was assessed after each injection. Injections of each nuclear region affected temporal and spatial features of the learned movement. However, the largest effects resulted from inactivating the interposed nuclei. These effects included an increased length of the reach trajectory, an accentuated deviation of the wrist trajectory from a straight line, cyclic movement of the distal extremity as the target was approached, a difficulty in grasping the bar, altered temporal features of the movement, and a highly characteristic change in the dimensionality measurements. The changes in dimensionality reflected a decreased correlation (linear interdependence) of the joint angular velocities coupled with an increased correlation among the linear velocities of markers located on the joints themselves. Related but less consistent changes in dimensionality resulted from fastigial injections. The motor sequence required to negotiate the template could be executed after the nuclear microinjections, indicating that retention of the motor sequence was not affected by the inactivation of any of the cerebellar nuclei. However, in two of the five animals, some decreases in performance were observed after dentate injection that were not characteristic of changes related to an effect on retention. These data suggest that the cerebellum plays an important role in regulating the consistent, stereotypic organization of complex goal-directed movements, including the temporal correlation among joint angle velocities. The data also indicate that the retention of the task is not dependent on any of the individual cerebellar nuclear regions. Consequently, these structures are unlikely to be critical storage sites for the engram established during the learning of this task.

A Tool for Estimating Variability in Wood Preservative Treatment Retention

Treesearch

Patricia K. Lebow; Adam M. Taylor; Timothy M. Young

2015-01-01

Composite sampling is standard practice for evaluation of preservative retention levels in preservative-treated wood. Current protocols provide an average retention value but no estimate of uncertainty. Here we describe a statistical method for calculating uncertainty estimates using the standard sampling regime with minimal additional chemical analysis. This tool can...

Features of separation on polymeric reversed phase for two classes of higher saturated fatty acids esters

NASA Astrophysics Data System (ADS)

Deineka, V. I.; Lapshova, M. S.; Zakharenko, E. V.; Deineka, L. A.

2013-11-01

The principles of sorption on polymeric reversed phase (PRP) YMS C30 for members of the two classes of esters formed by higher saturated fatty acids, i.e., lutein diesters ( I) and triacylglycerols ( II), are investigated. It is shown that the logarithm of the retention factor increases nonlinearly with an increase of the length of the acid radical, although the retention on PRP is higher in the case of I and lower in the case of II, compared to their retention on traditional monomeric reversed phase (MRP) Kromasil-100 5C18; however, the equivalence of the contributions to the retention of I that correspond to an identical change in acids, does not depend on the length of the hydrocarbon radical of the second acid. It is noted that the Van't Hoff plot for PRP contains a curve break, indicating a change in the retention mechanism upon a rise in temperature.

Increased Milk Protein Concentration in a Rehydration Drink Enhances Fluid Retention Caused by Water Reabsorption in Rats.

PubMed

Ito, Kentaro; Saito, Yuri; Ashida, Kinya; Yamaji, Taketo; Itoh, Hiroyuki; Oda, Munehiro

2015-01-01

A fluid-retention effect is required for beverages that are designed to prevent dehydration. That is, fluid absorbed from the intestines should not be excreted quickly; long-term retention is desirable. Here, we focused on the effect of milk protein on fluid retention, and propose a new effective oral rehydration method that can be used daily for preventing dehydration. We first evaluated the effects of different concentrations of milk protein on fluid retention by measuring the urinary volumes of rats fed fluid containing milk protein at concentrations of 1, 5, and 10%. We next compared the fluid-retention effect of milk protein-enriched drink (MPD) with those of distilled water (DW) and a sports drink (SD) by the same method. Third, to investigate the mechanism of fluid retention, we measured plasma insulin changes in rats after ingesting these three drinks. We found that the addition of milk protein at 5 or 10% reduced urinary volume in a dose-dependent manner. Ingestion of the MPD containing 4.6% milk protein resulted in lower urinary volumes than DW and SD. MPD also showed a higher water reabsorption rate in the kidneys and higher concentrations of plasma insulin than DW and SD. These results suggest that increasing milk protein concentration in a beverage enhances fluid retention, which may allow the possibility to develop rehydration beverages that are more effective than SDs. In addition, insulin-modifying renal water reabsorption may contribute to the fluid-retention effect of MPD.

Short-term memory across eye blinks.

PubMed

Irwin, David E

2014-01-01

The effect of eye blinks on short-term memory was examined in two experiments. On each trial, participants viewed an initial display of coloured, oriented lines, then after a retention interval they viewed a test display that was either identical or different by one feature. Participants kept their eyes open throughout the retention interval on some blocks of trials, whereas on others they made a single eye blink. Accuracy was measured as a function of the number of items in the display to determine the capacity of short-term memory on blink and no-blink trials. In separate blocks of trials participants were instructed to remember colour only, orientation only, or both colour and orientation. Eye blinks reduced short-term memory capacity by approximately 0.6-0.8 items for both feature and conjunction stimuli. A third, control, experiment showed that a button press during the retention interval had no effect on short-term memory capacity, indicating that the effect of an eye blink was not due to general motoric dual-task interference. Eye blinks might instead reduce short-term memory capacity by interfering with attention-based rehearsal processes.

Gaining insight in the behaviour of imidazolium-based ionic liquids as additives in reversed-phase liquid chromatography for the analysis of basic compounds.

PubMed

Ubeda-Torres, M T; Ortiz-Bolsico, C; García-Alvarez-Coque, M C; Ruiz-Angel, M J

2015-02-06

In reversed-phase liquid chromatography in the absence of additives, cationic basic compounds give rise to broad and asymmetrical peaks as a result of ionic interactions with residual free silanols on silica-based stationary phases. Ionic liquids (ILs), added to the mobile phase, have been suggested as alternatives to amines to block the activity of silanols. However, the dual character of ILs should be considered: both cation and anion may be adsorbed on the stationary phase, thereby creating a double asymmetrical layer positively or negatively charged, depending on the relative adsorption of both ions. In this work, a study of the performance of six imidazolium-based ILs (the chlorides and tetrafluoroborates of 1-ethyl-, 1-butyl- and 1-hexyl-3-methylimidazolium) as modifiers of the chromatographic behaviour of a group of 10 β-blockers is performed, and compared with triethylamine and dimethyloctylamine. In order to gain more insight in the behaviour of ILs in RPLC, the changes in the nature of the chromatographic system, at increasing concentration of the additives, were followed based on retention and peak shape modelling. The multiple interactions that amines and ILs experience inside the chromatographic system suggest that the suppressing potency should be measured based on the shape of chromatographic peaks and not on the changes in retention. The ILs 1-hexyl-3-methyl-imidazolium chloride and tetrafluoroborate offered the most interesting features for the separation of the basic drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

Charge retention test experiences on Hubble Space Telescope nickel-hydrogen battery cells

NASA Technical Reports Server (NTRS)

Nawrocki, Dave E.; Driscoll, J. R.; Armantrout, J. D.; Baker, R. C.; Wajsgras, H.

1993-01-01

The Hubble Space Telescope (HST) nickel-hydrogen battery module was designed by Lockheed Missile & Space Co (LMSC) and manufactured by Eagle-Picher Ind. (EPI) for the Marshall Space Flight Center (MSFC) as an Orbital Replacement Unit (ORU) for the nickel-cadmium batteries originally selected for this low earth orbit mission. The design features of the HST nickel hydrogen battery are described and the results of an extended charge retention test are summarized.

Optimized Delivery System Achieves Enhanced Endomyocardial Stem Cell Retention

PubMed Central

Behfar, Atta; Latere, Jean-Pierre; Bartunek, Jozef; Homsy, Christian; Daro, Dorothee; Crespo-Diaz, Ruben J.; Stalboerger, Paul G.; Steenwinckel, Valerie; Seron, Aymeric; Redfield, Margaret M.; Terzic, Andre

2014-01-01

Background Regenerative cell-based therapies are associated with limited myocardial retention of delivered stem cells. The objective of this study is to develop an endocardial delivery system for enhanced cell retention. Methods and Results Stem cell retention was simulated in silico using one and three-dimensional models of tissue distortion and compliance associated with delivery. Needle designs, predicted to be optimal, were accordingly engineered using nitinol – a nickel and titanium alloy displaying shape memory and super-elasticity. Biocompatibility was tested with human mesenchymal stem cells. Experimental validation was performed with species-matched cells directly delivered into Langendorff-perfused porcine hearts or administered percutaneously into the endocardium of infarcted pigs. Cell retention was quantified by flow cytometry and real time quantitative polymerase chain reaction methodology. Models, computing optimal distribution of distortion calibrated to favor tissue compliance, predicted that a 75°-curved needle featuring small-to-large graded side holes would ensure the highest cell retention profile. In isolated hearts, the nitinol curved needle catheter (C-Cath) design ensured 3-fold superior stem cell retention compared to a standard needle. In the setting of chronic infarction, percutaneous delivery of stem cells with C-Cath yielded a 37.7±7.1% versus 10.0±2.8% retention achieved with a traditional needle, without impact on biocompatibility or safety. Conclusions Modeling guided development of a nitinol-based curved needle delivery system with incremental side holes achieved enhanced myocardial stem cell retention. PMID:24326777

Influence of displacement damage on deuterium and helium retention in austenitic and ferritic-martensitic alloys considered for ADS service

NASA Astrophysics Data System (ADS)

Voyevodin, V. N.; Karpov, S. A.; Kopanets, I. E.; Ruzhytskyi, V. V.; Tolstolutskaya, G. D.; Garner, F. A.

2016-01-01

The behavior of ion-implanted hydrogen (deuterium) and helium in austenitic 18Cr10NiTi stainless steel, EI-852 ferritic steel and ferritic/martensitic steel EP-450 and their interaction with displacement damage were investigated. Energetic argon irradiation was used to produce displacement damage and bubble formation to simulate nuclear power environments. The influence of damage morphology and the features of radiation-induced defects on deuterium and helium trapping in structural alloys was studied using ion implantation, the nuclear reaction D(3He,p)4He, thermal desorption spectrometry and transmission electron microscopy. It was found in the case of helium irradiation that various kinds of helium-radiation defect complexes are formed in the implanted layer that lead to a more complicated spectra of thermal desorption. Additional small changes in the helium spectra after irradiation with argon ions to a dose of ≤25 dpa show that the binding energy of helium with these traps is weakly dependent on the displacement damage. It was established that retention of deuterium in ferritic and ferritic-martensitic alloys is three times less than in austenitic steel at damage of ∼1 dpa. The retention of deuterium in steels is strongly enhanced by presence of radiation damages created by argon ion irradiation, with a shift in the hydrogen release temperature interval of 200 K to higher temperature. At elevated temperatures of irradiation the efficiency of deuterium trapping is reduced by two orders of magnitude.

Idiopathic bile acid malabsorption--a review of clinical presentation, diagnosis, and response to treatment.

PubMed Central

Williams, A J; Merrick, M V; Eastwood, M A

1991-01-01

Between 1982 and 1989, the seven day retention of 75SeHCAT was measured in 181 patients with chronic diarrhoea that remained unexplained after full investigation. Altogether 121 of the 181 had a seven day 75SeHCAT retention greater than or equal to 15% and thus had no evidence of abnormal bile acid turnover. Twenty one had a seven day 75SeHCAT retention greater than or equal to 10% but less than 15%. Their clinical features were typical of the irritable bowel syndrome, and none of eight treated with cholestyramine showed symptomatic improvement. Sixteen patients had a seven day retention greater than or equal to 5% and less than 10%, six of whom had improved symptoms after treatment with bile acid chelating agents. The remaining 23 patients had a 75SeHCAT retention of less than 5% at seven days and responded to bile acid chelators. This group had a characteristic illness with intermittent watery diarrhoea, but no constitutional upset. It was not possible to distinguish the patients with bile acid malabsorption exclusively on the basis of the clinical symptoms and investigations, other than 75SeHCAT retention. We conclude that the measurement of 75SeHCAT retention is useful, appropriate, and necessary in patients with unexplained chronic diarrhoea. PMID:1916479

The Multi-Feature Hypothesis: Connectionist Guidelines for L2 Task Design

ERIC Educational Resources Information Center

Moonen, Machteld; de Graaff, Rick; Westhoff, Gerard; Brekelmans, Mieke

2014-01-01

This study focuses on the effects of task type on the retention and ease of activation of second language (L2) vocabulary, based on the multi-feature hypothesis (Moonen, De Graaff, & Westhoff, 2006). Two tasks were compared: a writing task and a list-learning task. It was hypothesized that performing the writing task would yield higher…

A biologically relevant method for considering patterns of oceanic retention in the Southern Ocean

NASA Astrophysics Data System (ADS)

Mori, Mao; Corney, Stuart P.; Melbourne-Thomas, Jessica; Klocker, Andreas; Sumner, Michael; Constable, Andrew

2017-12-01

Many marine species have planktonic forms - either during a larval stage or throughout their lifecycle - that move passively or are strongly influenced by ocean currents. Understanding these patterns of movement is important for informing marine ecosystem management and for understanding ecological processes generally. Retention of biological particles in a particular area due to ocean currents has received less attention than transport pathways, particularly for the Southern Ocean. We present a method for modelling retention time, based on the half-life for particles in a particular region, that is relevant for biological processes. This method uses geostrophic velocities at the ocean surface, derived from 23 years of satellite altimetry data (1993-2016), to simulate the advection of passive particles during the Southern Hemisphere summer season (from December to March). We assess spatial patterns in the retention time of passive particles and evaluate the processes affecting these patterns for the Indian sector of the Southern Ocean. Our results indicate that the distribution of retention time is related to bathymetric features and the resulting ocean dynamics. Our analysis also reveals a moderate level of consistency between spatial patterns of retention time and observations of Antarctic krill (Euphausia superba) distribution.

Retention of mothers and infants in the prevention of mother-to-child transmission of HIV programme is associated with individual and facility-level factors in Rwanda

PubMed Central

Woelk, Godfrey B; Ndatimana, Dieudonne; Behan, Sally; Mukaminega, Martha; Nyirabahizi, Epiphanie; Hoffman, Heather J; Mugwaneza, Placidie; Ribakare, Muhayimpundu; Amzel, Anouk; Phelps, B Ryan

2016-01-01

Objectives Investigate levels of retention at specified time periods along the prevention of mother-to-child transmission (PMTCT) cascade among mother-infant pairs as well as individual- and facility-level factors associated with retention. Methods A retrospective cohort of HIV-positive pregnant women and their infants attending five health centres from November 2010 to February 2012 in the Option B programme in Rwanda was established. Data were collected from several health registers and patient follow-up files. Additionally, informant interviews were conducted to ascertain health facility characteristics. Generalized estimating equation methods and modelling were utilized to estimate the number of mothers attending each antenatal care visit and assess factors associated with retention. Results Data from 457 pregnant women and 462 infants were collected at five different health centres (three urban and two rural facilities). Retention at 30 days after registration and retention at 6 weeks, 3, 6, 9 and 12 months post-delivery were analyzed. Based on an analytical sample of 348, we found that 58% of women and 81% of infants were retained in care within the same health facility at 12 months post-delivery, respectively. However, for mother-infant paired mothers, retention at 12 months was 74% and 79% for their infants. Loss to facility occurred early, with 26% to 33% being lost within 30 days post-registration. In a multivariable model retention was associated with being married, adjusted relative risk (ARR): 1.26, (95% confidence intervals: 1.11, 1.43); antiretroviral therapy eligible, ARR: 1.39, (1.12, 1.73) and CD4 count per 50 mm3, ARR: 1.02, (1.01, 1.03). Conclusions These findings demonstrate varying retention levels among mother-infant pairs along the PMTCT cascade in addition to potential determinants of retention to such programmes. Unmarried, apparently healthy, HIV-positive pregnant women need additional support for programme retention. With the significantly increased workload resulting from lifelong antiretroviral treatment for all HIV-positive pregnant women, strategies need to be developed to identify, provide support and trace these women at risk of loss to follow-up. This study provides further evidence for the need for such a targeted supportive approach. PMID:27443268

Optimizing the performance of a reactor by reducing the retention time and addition of glycerin for anaerobically digesting manure

PubMed Central

Timmerman, Maikel; Schuman, Els; van Eekert, Miriam; van Riel, Johan

2015-01-01

Anaerobic digestion of manure is a widely accepted technology for energy production. However, only a minimal portion of the manure production in the EU is anaerobically digested and occurs predominantly in codigestion plants. There is substantial potential for biogas plants that primarily operate on manure (>90%); however, the methane yields of manure are less compared to coproducts, which is one of the reasons for manure-based biogas plants often being economically non-viable. Therefore, it is essential to begin increasing the efficiency of these biogas plants. This study investigated the effect of decreasing retention time and introducing a moderate amount of glycerin on the biogas production as methods to improve efficiency. An experiment has been conducted with two different manure types in four biogas reactors. The results of the study demonstrated that, first, it was possible to decrease the retention time to 10–15 days; however, the effect on biogas production varied per manure type. Secondly, the biogas production almost triples at a retention time of 15.6 days with an addition of 4% glycerin. The relative production-enhancing effect of glycerin did not vary significantly with both manure types. However, the absolute production-enhancing effect of glycerin differed per manure type since the biogas production per gram VS differed per manure type. Thirdly, the positive effect of the glycerin input declines with shorter retention times. Therefore, the effect of glycerin addition depends on the manure type and retention time. PMID:25401272

Optimizing the performance of a reactor by reducing the retention time and addition of glycerin for anaerobically digesting manure.

PubMed

Timmerman, Maikel; Schuman, Els; van Eekert, Miriam; van Riel, Johan

2015-01-01

Anaerobic digestion of manure is a widely accepted technology for energy production. However, only a minimal portion of the manure production in the EU is anaerobically digested and occurs predominantly in codigestion plants. There is substantial potential for biogas plants that primarily operate on manure (>90%); however, the methane yields of manure are less compared to coproducts, which is one of the reasons for manure-based biogas plants often being economically non-viable. Therefore, it is essential to begin increasing the efficiency of these biogas plants. This study investigated the effect of decreasing retention time and introducing a moderate amount of glycerin on the biogas production as methods to improve efficiency. An experiment has been conducted with two different manure types in four biogas reactors. The results of the study demonstrated that, first, it was possible to decrease the retention time to 10-15 days; however, the effect on biogas production varied per manure type. Secondly, the biogas production almost triples at a retention time of 15.6 days with an addition of 4% glycerin. The relative production-enhancing effect of glycerin did not vary significantly with both manure types. However, the absolute production-enhancing effect of glycerin differed per manure type since the biogas production per gram VS differed per manure type. Thirdly, the positive effect of the glycerin input declines with shorter retention times. Therefore, the effect of glycerin addition depends on the manure type and retention time.

Efforts to Improve Undergraduate Student Retention Rates at a Hispanic Serving Institution: Building Collaborative Relationships for the Common Good

ERIC Educational Resources Information Center

Martin, Nancy K.; Meyer, Kristi

2010-01-01

This article describes efforts to improve retention and graduation rates at the University of Texas at San Antonio, a large Hispanic serving institution (HSI). One college within the university is focusing on increasing retention and graduation rates primarily by building relationships and capitalizing on university resources. In addition to…

Urinary retention, erectile dysfunction and meningitis due to sacral herpes zoster: a case report and review of the literature.

PubMed

Erol, B; Avci, A; Eken, C; Ozgok, Y

2009-01-01

Zona zoster infection is often associated with painful erythematous vesicular eruptions of the skin or mucous membranes. Varicella zoster virus which stays latent in the sensorial root ganglia causes zona zoster infection. The most recognized feature of zona zoster is the dermatomal distribution of vesicular rashes. In the present case report, we state an unusual presentation of sacral zona zoster with urinary retention, erectile dysfunction and meningitis. Copyright 2009 S. Karger AG, Basel.

Trapping, retention and laser cooling of Th3+ ions in a multisection linear quadrupole trap

NASA Astrophysics Data System (ADS)

Borisyuk, P. V.; Vasil'ev, O. S.; Derevyashkin, S. P.; Kolachevsky, N. N.; Lebedinskii, Yu. Yu.; Poteshin, S. S.; Sysoev, A. A.; Tkalya, E. V.; Tregubov, D. O.; Troyan, V. I.; Khabarova, K. Yu.; Yudin, V. I.; Yakovlev, V. P.

2017-06-01

A multisection linear quadrupole trap for Th3+ ions is described. Multiply charged ions are obtained by the laser ablation method. The possibility of trapping and retention of ˜103 ions is demonstrated in macroscopic time scales of ˜30 s. Specific features of cooling Th3+ ions on the electron transitions with wavelengths of 1088, 690 and 984 nm in Th3+ ion are discussed; a principal scheme of a setup for laser cooling is presented.

Quantitative structure-retention relationship studies using immobilized artificial membrane chromatography I: amended linear solvation energy relationships with the introduction of a molecular electronic factor.

PubMed

Li, Jie; Sun, Jin; Cui, Shengmiao; He, Zhonggui

2006-11-03

Linear solvation energy relationships (LSERs) amended by the introduction of a molecular electronic factor were employed to establish quantitative structure-retention relationships using immobilized artificial membrane (IAM) chromatography, in particular ionizable solutes. The chromatographic indices, log k(IAM), were determined by HPLC on an IAM.PC.DD2 column for 53 structurally diverse compounds, including neutral, acidic and basic compounds. Unlike neutral compounds, the IAM chromatographic retention of ionizable compounds was affected by their molecular charge state. When the mean net charge per molecule (delta) was introduced into the amended LSER as the sixth variable, the LSER regression coefficient was significantly improved for the test set including ionizable solutes. The delta coefficients of acidic and basic compounds were quite different indicating that the molecular electronic factor had a markedly different impact on the retention of acidic and basic compounds on IAM column. Ionization of acidic compounds containing a carboxylic group tended to impair their retention on IAM, while the ionization of basic compounds did not have such a marked effect. In addition, the extra-interaction with the polar head of phospholipids might cause a certain change in the retention of basic compounds. A comparison of calculated and experimental retention indices suggested that the semi-empirical LSER amended by the addition of a molecular electronic factor was able to reproduce adequately the experimental retention factors of the structurally diverse solutes investigated.

Prediction of endoplasmic reticulum resident proteins using fragmented amino acid composition and support vector machine.

PubMed

Kumar, Ravindra; Kumari, Bandana; Kumar, Manish

2017-01-01

The endoplasmic reticulum plays an important role in many cellular processes, which includes protein synthesis, folding and post-translational processing of newly synthesized proteins. It is also the site for quality control of misfolded proteins and entry point of extracellular proteins to the secretory pathway. Hence at any given point of time, endoplasmic reticulum contains two different cohorts of proteins, (i) proteins involved in endoplasmic reticulum-specific function, which reside in the lumen of the endoplasmic reticulum, called as endoplasmic reticulum resident proteins and (ii) proteins which are in process of moving to the extracellular space. Thus, endoplasmic reticulum resident proteins must somehow be distinguished from newly synthesized secretory proteins, which pass through the endoplasmic reticulum on their way out of the cell. Approximately only 50% of the proteins used in this study as training data had endoplasmic reticulum retention signal, which shows that these signals are not essentially present in all endoplasmic reticulum resident proteins. This also strongly indicates the role of additional factors in retention of endoplasmic reticulum-specific proteins inside the endoplasmic reticulum. This is a support vector machine based method, where we had used different forms of protein features as inputs for support vector machine to develop the prediction models. During training leave-one-out approach of cross-validation was used. Maximum performance was obtained with a combination of amino acid compositions of different part of proteins. In this study, we have reported a novel support vector machine based method for predicting endoplasmic reticulum resident proteins, named as ERPred. During training we achieved a maximum accuracy of 81.42% with leave-one-out approach of cross-validation. When evaluated on independent dataset, ERPred did prediction with sensitivity of 72.31% and specificity of 83.69%. We have also annotated six different proteomes to predict the candidate endoplasmic reticulum resident proteins in them. A webserver, ERPred, was developed to make the method available to the scientific community, which can be accessed at http://proteininformatics.org/mkumar/erpred/index.html. We found that out of 124 proteins of the training dataset, only 66 proteins had endoplasmic reticulum retention signals, which shows that these signals are not an absolute necessity for endoplasmic reticulum resident proteins to remain inside the endoplasmic reticulum. This observation also strongly indicates the role of additional factors in retention of proteins inside the endoplasmic reticulum. Our proposed predictor, ERPred, is a signal independent tool. It is tuned for the prediction of endoplasmic reticulum resident proteins, even if the query protein does not contain specific ER-retention signal.

Hydrogen retention in lithium and lithium oxide films

NASA Astrophysics Data System (ADS)

Buzi, L.; Yang, Y.; Domínguez-Gutiérrez, F. J.; Nelson, A. O.; Hofman, M.; Krstić, P. S.; Kaita, R.; Koel, B. E.

2018-04-01

Pure lithium (Li) surfaces are difficult to maintain in fusion devices due to rapid oxide formation, therefore, parameterizing and understanding the mechanisms of hydrogen (H, D) retention in lithium oxide (Li2O) in addition to pure Li is crucial for Li plasma-facing material applications. To compare H retention in Li and Li2O films, measurements were made as a function of surface temperature (90-520 K) under ultrahigh vacuum (UHV) conditions using temperature programmed desorption (TPD). In both cases, the total retention dropped with surface temperature, from 95% at 90 K to 35% at 520 K Li2O films retained H in similar amounts as pure Li. Molecular Dynamics (MD) modeling was used to elucidate the mechanisms of H retention, and results were consistent with experiments in terms of both retention fraction and the drop of retention with temperature.

Soil processes drive seasonal variation in retention of 15N tracers in a deciduous forest catchment.

PubMed

Goodale, Christine L; Fredriksen, Guinevere; Weiss, Marissa S; McCalley, K; Sparks, Jed P; Thomas, Steven A

2015-10-01

Seasonal patterns of stream nitrate concentration have long been interpreted as demonstrating the central role of plant uptake in regulating stream nitrogen loss from forested catchments. Soil processes are rarely considered as important drivers of these patterns. We examined seasonal variation in N retention in a deciduous forest using three whole-ecosystem 15N tracer additions: in late April (post-snowmelt, pre-leaf-out), late July (mid-growing- season), and late October (end of leaf-fall). We expected that plant 15N uptake would peak in late spring and midsummer, that immobilization in surface litter and soil would peak the following autumn leaf-fall, and that leaching losses would vary inversely with 15N retention. Similar to most other 15N tracer studies, we found that litter and soils dominated ecosystem retention of added 15N. However, 15N recovery in detrital pools varied tremendously by season, with > 90% retention in spring and autumn and sharply reduced 15N retention in late summer. During spring, over half of the 15N retained in soil occurred within one day in the heavy (mineral-associated) soil fraction. During summer, a large decrease in 15N retention one week after addition coincided with increased losses of 15NO3- to soil leachate and seasonal increases in soil and stream NO3- concentrations, although leaching accounted for only a small fraction of the lost 15N (< 0.2%). Uptake of 15N into roots did not vary by season and accounted for < 4% of each tracer addition. Denitrification or other processes that lead to N gas loss may have consumed the rest. These measurements of 15N movement provide strong evidence for the dominant role of soil processes in regulating seasonal N retention and losses in this catchment and perhaps others with similar soils.

What Models of Verbal Working Memory Can Learn from Phonological Theory: Decomposing the Phonological Similarity Effect

ERIC Educational Resources Information Center

Schweppe, Judith; Grice, Martine; Rummer, Ralf

2011-01-01

Despite developments in phonology over the last few decades, models of verbal working memory make reference to phoneme-sized phonological units, rather than to the features of which they are composed. This study investigates the influence on short-term retention of such features by comparing the serial recall of lists of syllables with varying…

A clinical evaluation denture adhesives used by patients with xerostomia.

PubMed

Bogucki, Zdzislaw A; Napadlek, Piotr; Dabrowa, Tomasz

2015-02-01

The purpose of study was to analyze the participants' opinions concerning the effectiveness of 6 denture adhesives (DA). The study group included 60 participants. Criteria for selecting the patients were as follows: reduced retention and stabilization of maxillary complete dentures and xerostomia. These features were evaluated on basis of clinical examination and standard sialometry tests (u-SFR). Retention of maxillary dentures was scored by modified Kapur index before application of DA. All participants were divided randomly into 6 groups regarding the use of the 6 DA during a 6-month period. After this time, participants completed an HRQL questionnaire. DA noticeably improved retention and stabilization of maxillary complete dentures. DA in the glue form had the best retention effectiveness in participants with xerostomia. These materials are difficult to clean from the denture base. The data are presented in tables and figures. The results of the study collected positive influence of adhesives on retention of dentures in xerostomia patients. The cleaning dentures and denture bearing tissues was difficult. DA help in the use of prostheses, but it is also necessary for the treatment of the causes and symptoms of xerostomia.

Eosinophilic cystitis with recurrent urinary retention: case report.

PubMed

Park, Hongzoo

2017-01-01

Eosinophilic cystitis is a rare inflammatory disease of the bladder whose origin, pathogenesis, and treatment are unknown. Frequency, dysuria, and hematuria are frequent symptoms. Here, we report a rare occurrence of recurrent urinary retention and repetitive catheterization. A 67-year-old male presented with acute urinary retention and intermittent gross hematuria of 2 weeks duration. Urethral catheterization followed by a trial without catheter, was successful. Complete blood count showed presence of eosinophils (eosinophilia) and computed tomography of kidneys, ureter and bladder with contrast showed thickened bladder wall and small prostate. Cystoscopy revealed an erythematous lesion over the anterior wall. The rest of the mucosa was normal. Transurethral biopsies of the lesion were performed and histologic examination showed features of eosinophilic cystitis. Despite multiple medication regimens containing corticosteroids and antihistamines, he presented with recurrent urinary retention, approximately once every month. After 6 months, he was started on bethanechol, which led to no catheterization for up to 2 years. To the best of our knowledge, this is the first report on the successful use of bethanechol as a treatment for eosinophilic cystitis with recurrent urinary retention.

Green hydrophilic interaction chromatography using ethanol-water-carbon dioxide mixtures.

PubMed

Pereira, Alberto dos Santos; Girón, Ana Jiménez; Admasu, Engdawork; Sandra, Pat

2010-03-01

In hydrophilic interaction chromatography (HILIC), best results are obtained with high concentrations of acetonitrile. In the framework of green chromatography, different concentrations of carbon dioxide were added to the mobile phases acetonitrile-water and ethanol-water and the impact on retention and separation in HILIC using bare silica as stationary phase was explored. The features of HILIC using enhanced-fluidity mobile phases are illustrated with the analysis of the nucleobases and a mixture containing the nucleobases and cortisol, flurbiprofen, theophylline and caffeine. For both organic constituents, the elution window is widened in function of the carbon dioxide concentration and selectivity changes. At high concentrations of carbon dioxide in ethanol, separations were similar to those obtained with acetonitrile without carbon dioxide addition.

Twin-bit via resistive random access memory in 16 nm FinFET logic technologies

NASA Astrophysics Data System (ADS)

Shih, Yi-Hong; Hsu, Meng-Yin; King, Ya-Chin; Lin, Chrong Jung

2018-04-01

A via resistive random access memory (RRAM) cell fully compatible with the standard CMOS logic process has been successfully demonstrated for high-density logic nonvolatile memory (NVM) modules in advanced FinFET circuits. In this new cell, the transition metal layers are formed on both sides of a via, given two storage bits per via. In addition to its compact cell area (1T + 14 nm × 32 nm), the twin-bit via RRAM cell features a low operation voltage, a large read window, good data retention, and excellent cycling capability. As fine alignments between mask layers become possible, the twin-bit via RRAM cell is expected to be highly scalable in advanced FinFET technology.

RSNA Diagnosis Live: A Novel Web-based Audience Response Tool to Promote Evidence-based Learning.

PubMed

Awan, Omer A; Shaikh, Faiq; Kalbfleisch, Brian; Siegel, Eliot L; Chang, Paul

2017-01-01

Audience response systems have become more commonplace in radiology residency programs in the last 10 years, as a means to engage learners and promote improved learning and retention. A variety of systems are currently in use. RSNA Diagnosis Live™ provides unique features that are innovative, particularly for radiology resident education. One specific example is the ability to annotate questions with subspecialty tags, which allows resident performance to be tracked over time. In addition, deficiencies in learning can be monitored for each trainee and analytics can be provided, allowing documentation of resident performance improvement. Finally, automated feedback is given not only to the instructor, but also to the trainee. Online supplemental material is available for this article. © RSNA, 2017.

Engagement, compliance and retention with a gamified online social networking physical activity intervention.

PubMed

Ryan, Jillian; Edney, Sarah; Maher, Carol

2017-12-01

Health behaviour interventions delivered via online social networks are an increasingly popular approach to addressing lifestyle-related health problems. However, research to date consistently reports poor user engagement and retention. The current study examined user engagement, compliance and retention with Active Team-a gamified physical activity intervention delivered by via an online Facebook application. Associations between engagement and participant (n = 51) demographic and team characteristics (sex, age, education and team size) were examined, as well as temporal trends in engagement during the 50-day intervention. Analyses revealed significant associations between both engagement (p = <0.001) and gamification (p = 0.04) with education, with participants in the middle education category appearing to have the highest rates of engagement and use of gamification features. Gender was also related to engagement, with males demonstrating the highest use of the intervention's gamification features (p = 0.004). Although compliance was consistently high for the duration, engagement declined steadily throughout the intervention. Engagement peaked on Wednesdays, coinciding with the delivery of a customised email reminder. Findings reveal individual differences in engagement with Active Team, highlighting a need to tailor interventions to the target audience. Gamification features may enhance engagement amongst males, who are traditionally recognised as a difficult demographic group to engage. Finally, the use of customised, periodic push reminders delivered by email may enhance user engagement by drawing them back to the intervention and helping to sustain intervention behaviours.

Lacosamide in the treatment of patients with epilepsy and intellectual disabilities: A long-term study of 136 patients.

PubMed

Böttcher, Stefan; Lutz, Martin T; Mayer, Thomas

2017-10-01

This study aimed to analyze the retention rate of lacosamide (LCM) in patients with epilepsy and intellectual disabilities (IDs), to identify factors influencing retention rate, and to investigate the LCM retention rate with and without concomitant sodium channel blocker (SCB). We hypothesized that the retention rate of LCM with concomitant SCB would be lower than without SCB. Using the Kaplan-Meier estimator, we conducted a monocentric, retrospective, observational, open-label study to evaluate LCM retention rates in patients with IDs and drug-resistant epilepsy. In addition, the impact of therapy-related variables on the long-term retention of LCM was evaluated. One hundred thirty-six subjects with IDs and drug-resistant epilepsy were included (age 2-66 years); most patients had focal epilepsy. Long-term retention rates were 62.0% at 1 year, 43.7% at 2 years, and 29.1% at 3 and 4 years. Reasons for LCM discontinuation included insufficient therapeutic benefits (69%), adverse events (11%), or a combination of both factors (8%). The LCM retention rate was influenced by the number of background antiepileptic drugs (AEDs). An additional and independent influence of concomitant therapy with SCB on retention rate could not be confirmed. One of the major challenges in medically caring for patients with epilepsy and IDs is the high rate of drug resistance. However, there is a lack of evidence-based information about the efficacy and tolerability of AEDs in this population. It has been shown that concomitant SCB use is a key factor in increasing the risk of LCM failure in children with epilepsy. This finding has not been replicated in our predominantly adult sample of patients with IDs. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Rapid identification of fatty acid methyl esters using a multidimensional gas chromatography-mass spectrometry database.

PubMed

Härtig, Claus

2008-01-04

A multidimensional approach for the identification of fatty acid methyl esters (FAME) based on GC/MS analysis is described. Mass spectra and retention data of more than 130 FAME from various sources (chain lengths in the range from 4 to 24 carbon atoms) were collected in a database. Hints for the interpretation of FAME mass spectra are given and relevant diagnostic marker ions are deduced indicating specific groups of fatty acids. To verify the identity of single species and to ensure an optimized chromatographic resolution, the database was compiled with retention data libraries acquired on columns of different polarity (HP-5, DB-23, and HP-88). For a combined use of mass spectra and retention data standardized methods of measurement for each of these columns are required. Such master methods were developed and always applied under the conditions of retention time locking (RTL) which allowed an excellent reproducibility and comparability of absolute retention times. Moreover, as a relative retention index system, equivalent chain lengths (ECL) of FAME were determined by linear interpolation. To compare and to predict ECL values by means of structural features, fractional chain lengths (FCL) were calculated and fitted as well. As shown in an example, the use of retention data and mass spectral information together in a database search leads to an improved and reliable identification of FAME (including positional and geometrical isomers) without further derivatizations.

The effect of earthworms (Lumbricus rubellus) in feed formulation on growth and retention of eel (Anguilla bicolor)

NASA Astrophysics Data System (ADS)

Jatmiko, P. C.; Madinah, N. A.; Agustono; Nurhajati, T.

2018-04-01

Earthworms (Lumbricus rubellus) has high protein content. The addition of earthworms in formulation feed not only can increase the appetite of eel but also increase the nutritional content in feed. The purpose of this research was to know the potention of earthworms L. rubellus in feed formulation that can gives increase on the growth and retention. Research’s method was using Complete Randomized Design (CRD) consisted of five treatments and four replication. Treatments in this research ware the different addition of earthworms L. rubellus in feed formulation which were 0 %, 25 %, 50 %, 75 % and 100 %. The result showed that there were significantly different on the growth and retention of eel during maintenance for 21 days. the best result was on the 100% of earthworms L.rubellus addition.

"The nurse satisfaction, service quality and nurse retention chain": implications for management of recruitment and retention.

PubMed

Newman, Karin; Maylor, Uvanney; Chansarkar, Bal

2002-01-01

This paper presents the findings of a qualitative study, based on interviews with over 130 nurses and midwives in four London Trust hospitals on: the main factors influencing nurse satisfaction and retention; empirical support for the robustness of a conceptual framework or model "the nurse satisfaction, service quality and nurse retention chain"; and some managerial considerations for recruitment and retention. The three main factors influencing job satisfaction were patients, the inherent characteristics of nursing and the nursing team; the two main sources of job dissatisfaction were staff shortages and poor management and amongst nurse retention strategies improving working conditions was more important than increased pay. For recruitment, as well as retention, improving the image and reputation of nursing along with improvements in work-life balance were pre-requisites for meeting the challenging target of an additional 20,000 nurses on the wards by 2004.

The Baptist Health Nurse Retention Questionnaire: A Methodological Study, Part 1.

PubMed

Lengerich, Alexander; Bugajski, Andrew; Marchese, Matthew; Hall, Brittany; Yackzan, Susan; Davies, Claire; Brockopp, Dorothy

2017-05-01

The purposes of this study were to develop and test the Baptist Health Nurse Retention Questionnaire (BHNRQ) and examine the importance of nurse retention factors. Multiple factors, including increasing patient acuity levels, have led to concerns regarding nurse retention. An understanding of current factors related to retention is limited. To establish the psychometric properties of the BHNRQ, data were collected from 279 bedside nurses at a 391-bed, Magnet® redesignated community hospital. A principal component analysis was conducted to determine the subscale structure of the BHNRQ. Additional analyses were conducted related to content validity and test-retest reliability. The results of the principal components analysis revealed 3 subscales: nursing practice, management, and staffing. Analyses demonstrate that the BHNRQ is a reliable and valid instrument for measuring nurse retention factors. The BHNRQ was found to be a clinically useful instrument for measuring important factors related to nurse retention.

Hydrogen retention in lithium and lithium oxide films

DOE PAGES

Buzi, L.; Yang, Y.; Dominguez-Gutierrez, F. J.; ...

2018-02-09

Pure lithium (Li) surfaces are difficult to maintain in fusion devices due to rapid oxide formation, therefore, parameterizing and understanding the mechanisms of hydrogen (H, D) retention in lithium oxide (Li 2O) in addition to pure Li is crucial for Li plasma-facing material applications. To compare H retention in Li and Li 2O films, measurements were made as a function of surface temperature (90–520 K) under ultrahigh vacuum (UHV) conditions using temperature programmed desorption (TPD). In both cases, the total retention dropped with surface temperature, from 95% at 90 K to 35% at 520 K Li 2O films retained Hmore » in similar amounts as pure Li. Finally, Molecular Dynamics (MD) modeling was used to elucidate the mechanisms of H retention, and results were consistent with experiments in terms of both retention fraction and the drop of retention with temperature.« less

Hydrogen retention in lithium and lithium oxide films

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

Buzi, L.; Yang, Y.; Dominguez-Gutierrez, F. J.

Pure lithium (Li) surfaces are difficult to maintain in fusion devices due to rapid oxide formation, therefore, parameterizing and understanding the mechanisms of hydrogen (H, D) retention in lithium oxide (Li 2O) in addition to pure Li is crucial for Li plasma-facing material applications. To compare H retention in Li and Li 2O films, measurements were made as a function of surface temperature (90–520 K) under ultrahigh vacuum (UHV) conditions using temperature programmed desorption (TPD). In both cases, the total retention dropped with surface temperature, from 95% at 90 K to 35% at 520 K Li 2O films retained Hmore » in similar amounts as pure Li. Finally, Molecular Dynamics (MD) modeling was used to elucidate the mechanisms of H retention, and results were consistent with experiments in terms of both retention fraction and the drop of retention with temperature.« less

Epigenetic Transgenerational Inheritance of Altered Sperm Histone Retention Sites.

PubMed

Ben Maamar, Millissia; Sadler-Riggleman, Ingrid; Beck, Daniel; Skinner, Michael K

2018-03-28

A variety of environmental toxicants and factors have been shown to induce the epigenetic transgenerational inheritance of disease and phenotypic variation. Epigenetic alterations in the germline (sperm or egg) are required to transmit transgenerational phenotypes. The current study was designed to investigate the potential role of histones in sperm to help mediate the epigenetic transgenerational inheritance. The agricultural fungicide vinclozolin and the pesticide DDT (dichlorodiphenyltrichloroethane) were independently used to promote the epigenetic transgenerational inheritance of disease. Purified cauda epididymal sperm were collected from the transgenerational F3 generation control and exposure lineage male rats for histone analysis. A reproducible core of histone H3 retention sites was observed using an H3 chromatin immunoprecipitation (ChIP-Seq) analysis in control lineage sperm. Interestingly, the same core group of H3 retention sites plus additional differential histone retention sites (DHRs) were observed in the F3 generation exposure lineage sperm. Although new histone H3 retention sites were observed, negligible change in histone modification (methylation of H3K27me3) was observed between the control and exposure lineages. Observations demonstrate that in addition to alterations in sperm DNA methylation and ncRNA previously identified, the induction of differential histone retention sites (DHRs) also appear to be involved in environmentally induced epigenetic transgenerational inheritance.

Soluble reactive phosphorus (SRP) transport and retention in tropical, rain forest streams draining a volcanic landscape in Costa Rica: In situ SRP amendment to streams and laboratory studies

USGS Publications Warehouse

Triska, F.; Pringle, C.M.; Duff, J.H.; Avanzino, R.J.; Zellweger, G.

2006-01-01

Soluble reactive phosphorus (SRP) transport/retention was determined in two rain forest streams (Salto, Pantano) draining La Selva Biological Station, Costa Rica. There, SRP levels can be naturally high due to groundwater enriched by geothermal activity within the surfically dormant volcanic landscape, and subsequently discharged at ambient temperature. Combined field and laboratory approaches simulated high but natural geothermal SRP input with the objective of estimating the magnitude of amended SRP retention within high and low SRP settings and determining the underlying mechanisms of SRP retention. First, we examined short-term SRP retention/transport using combined SRP-conservative tracer additions at high natural in situ concentrations. Second, we attempted to observe a DIN response during SRP amendment as an indicator of biological uptake. Third, we determined SRP release/retention using laboratory sediment assays under control and biologically inhibited conditions. Short-term in situ tracer-SRP additions indicated retention in both naturally high and low SRP reaches. Retention of added SRP mass in Upper Salto (low SRP) was 17% (7.5 mg-P m-2 h-1), and 20% (10.9 mg-P m-2 h -1) in Lower Salto (high SRP). No DIN response in either nitrate or ammonium was observed. Laboratory assays using fresh Lower Salto sediments indicated SRP release (15.4 ?? 5.9 ??g-P g dry wt.-1 h -1), when incubated in filter sterilized Salto water at ambient P concentration, but retention when incubated in filter sterilized river water amended to 2.0 mg SRP l-1 (233.2 ?? 5.8 ??g-P g dry wt. -1 h-1). SRP uptake/release was similar in both control- and biocide-treated sediments indicating predominantly abiotic retention. High SRP retention even under biologically saturated conditions, absence of a DIN response to amendment, patterns of desorption following amendment, and similar patterns of retention and release under control and biologically inhibited conditions all indicated predominantly abiotic P flux. ?? 2006 Springer Science+Business Media, Inc.

Interference in Verbal Working Memory: Distinguishing Similarity-Based Confusion, Feature Overwriting, and Feature Migration

ERIC Educational Resources Information Center

Oberauer, Klaus; Lange, Elke B.

2008-01-01

Reports two experiments on mechanism of interference in working memory. Experiment 1 shows that a target word in a memory list, which bears high similarity to one of 4 words read aloud in the retention interval, is recalled less well than a control word. A second target word, not similar to any word read aloud but with all its phonemes repeated…

A new mathematical model for nitrogen gas production with special emphasis on the role of attached growth media in anammox hybrid reactor.

PubMed

Tomar, Swati; Gupta, Sunil Kumar

2015-11-01

The present study emphasised on the development of new mathematical models based on mass balance and stoichiometry of nitrogen removal in anammox hybrid reactor (AHR). The performance of AHR at varying hydraulic retention times (HRTs) and nitrogen loading rates (NLRs) revealed that nitrogen removal efficiency (NRE) increases with increase in HRT and was found optimal (89 %) at HRT of 2 days. Mass balance of nitrogen revealed that major fraction (74.1 %) of input nitrogen is converted into N2 gas followed by 11.2 % utilised in biomass synthesis. Attached growth media (AGM) in AHR contributed to an additional 15.4 % ammonium removal and reduced the sludge washout rate by 29 %. This also enhanced the sludge retention capacity of AHR and thus minimised the formation of nitrate in the treated effluent, which is one of the bottlenecks of anammox process. Process kinetics was also studied using various mathematical models. The mass balance model derived from total nitrogen was found most precise and predicted N2 gas with least error (1.68 ± 4.44 %). Model validation for substrate removal kinetics dictated comparatively higher correlation for Grau second-order model (0.952) than modified Stover-Kincannon model (0.920). The study concluded that owing to features of high biomass retention, less nitrate formation and consistently higher nitrogen removal efficiency, this reactor configuration is techno-economically most efficient and viable. The study opens the door for researchers and scientists for pilot-scale testing of AHR leading to its wide industrial application.

[Mucous retention cysts of the minor salivary glands. A specific type of mucocele].

PubMed

Kakarantza-Angelopoulou, E; Triantaphyllou, A

1989-08-01

The mucous retention cyst of the minor salivary glands represent a specific type of oral mucocele which is lined by epithelium. It is caused probably from partial or complete obstruction of a duct. It affects older patients (over 40 years of age) most commonly women and it is located in different sites than the ordinary mucocele. In this paper we studied the histologic and histochemical features of four cases. The lining epithelium varied from cuboidal to columnar or flattened. Among the cells of the lining epithelium oncocytes were observed.

Role of different salt marsh plants on metal retention in an urban estuary (Lima estuary, NW Portugal)

NASA Astrophysics Data System (ADS)

Almeida, C. M. R.; Mucha, Ana P.; Teresa Vasconcelos, M.

2011-01-01

The aim of the present work was to understand the role different salt marsh plants on metal distribution and retention in the Lima River estuary (NW Portugal), which to our knowledge have not been ascertained in this area yet. The knowledge of these differences is an important requirement for the development of appropriate management strategies, and is poorly described for Eurosiberian estuaries, like the one selected. In addition it is important to understand the difference among introduced and native salt marsh plants. In this work, metal levels (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were surveyed (by atomic absorption spectrometry) in sediments from sites vegetated with Juncus maritimus, Spartina patens, Phragmites australis and Triglochin striata (rhizo-sediments), in non-vegetated sediments and in the different tissues of the plants (roots, rhizomes and aerial shoots). In general, rhizo-sediments had higher metal concentrations than non-vegetated sediments, a feature that seems common to sediments colonized by salt marsh plants of different estuarine areas. All plants concentrated metals, at least Cd, Cu and Zn (and Pb for T. striata) in their belowground structures ([ M] belowground tissues/[ M] non-vegetated sediment > 1). However, when considered per unit of salt marsh area, the different selected plants played a different role on sediment metal distribution and retention. Triglochin striata retained a significant metal burden in it belowground structures (root plus rhizomes) acting like a possible phyto-stabilizer, whereas P. australis had an higher metal burden in aboveground tissues acting as a possible phyto-extractor. As for J. maritimus and S. patens, metal burden distribution between above and belowground structures depended on the metal, with J. maritimus retaining, for instance, much more Cd and Cu in the aboveground than in the belowground structures. Therefore, the presence of invasive and exotic plants in some areas of the salt marsh may considerably affect metal distribution and retention in the estuarine region.

Differences in medical schools' regional retention of physicians by school type and year of establishment: effect of new schools built under government policy.

PubMed

Kamitani, Satoru; Nakamura, Fumiaki; Itoh, Mitsuko; Sugiyama, Takehiro; Toyokawa, Satoshi; Kobayashi, Yasuki

2015-12-30

Physician maldistribution is an ongoing concern globally. The extent of medical schools retaining graduates within their geographical areas has rarely been explored in Japan or in other countries. This study aimed to investigate whether the proportion of medical school graduates practicing in the vicinity of medical school (retention rate) differs by the year of the school's establishment and by the school's funding source. This cross-sectional study used a set of databases on medical institutions and personnel. We analyzed a sample of 168,594 clinically active physicians practicing in institutions as of May 2014, who passed the National Medical Practitioners Examination between 1985 and 2013. We assessed the retention rate and the schools' establishment period and funding source (pre-1970/post-1970, private/public), using a hierarchical regression model with random intercept unique to each medical school. We used the following factors as covariates: gender, physicians' length of professional experience, and the geographical features of the medical schools. The retention rate was widely distributed from 16.2 to 81.5 % (median: 48.4 %). Physicians who graduated from post-1970 medical schools were less likely to practice in the prefecture of their medical school location, relative to those who graduated from pre-1970 medical schools (adjusted odds ratio: 0.75; 95 % confidence interval: 0.62-0.90). Physicians who graduated from private medical schools were also less likely to practice in the prefecture of their medical school location, relative to those who graduated from public medical schools (adjusted odds ratio: 0.63; 95 % confidence interval: 0.51-0.77). In addition, the ability to retain graduates varied by school according to the school's characteristics. There was a considerable difference between medical schools in retaining graduates locally. The study results may have significant implications for government policy to alleviate maldistribution of physicians in Japan.

Chocolate HILIC phases: development and characterization of novel saccharide-based stationary phases by applying non-enzymatic browning (Maillard reaction) on amino-modified silica surfaces.

PubMed

Schuster, Georg; Lindner, Wolfgang

2011-06-01

Novel saccharide-based stationary phases were developed by applying non-enzymatic browning (Maillard Reaction) on aminopropyl silica material. During this process, the reducing sugars glucose, lactose, maltose, and cellobiose served as "ligand primers". The reaction cascade using cellobiose resulted in an efficient chromatographic material which further served as our model Chocolate HILIC column. (Chocolate refers to the fact that these phases are brownish.) In this way, an amine backbone was introduced to facilitate convenient manipulation of selectivity by additional attractive or repulsive ionic solute-ligand interactions in addition to the typical HILIC retention mechanism. In total, six different test sets and five different mobile phase compositions were investigated, allowing a comprehensive evaluation of the new polar column. It became evident that, besides the so-called HILIC retention mechanism based on partition phenomena, additional adsorption mechanisms, including ionic interactions, take place. Thus, the new column is another example of a HILIC-type column characterized by mixed-modal retention increments. The glucose-modified materials exhibited the relative highest overall hydrophobicity of all grafted Chocolate HILIC columns which enabled retention of lipophilic analytes with high water content mobile phases.

A Clinical Evaluation Denture Adhesives Used by Patients With Xerostomia

PubMed Central

Bogucki, Zdzislaw A.; Napadlek, Piotr; Dabrowa, Tomasz

2015-01-01

Abstract The purpose of study was to analyze the participants’ opinions concerning the effectiveness of 6 denture adhesives (DA). The study group included 60 participants. Criteria for selecting the patients were as follows: reduced retention and stabilization of maxillary complete dentures and xerostomia. These features were evaluated on basis of clinical examination and standard sialometry tests (u-SFR). Retention of maxillary dentures was scored by modified Kapur index before application of DA. All participants were divided randomly into 6 groups regarding the use of the 6 DA during a 6-month period. After this time, participants completed an HRQL questionnaire. DA noticeably improved retention and stabilization of maxillary complete dentures. DA in the glue form had the best retention effectiveness in participants with xerostomia. These materials are difficult to clean from the denture base. The data are presented in tables and figures. The results of the study collected positive influence of adhesives on retention of dentures in xerostomia patients. The cleaning dentures and denture bearing tissues was difficult. DA help in the use of prostheses, but it is also necessary for the treatment of the causes and symptoms of xerostomia. PMID:25700320

A general strategy for performing temperature-programming in high performance liquid chromatography--further improvements in the accuracy of retention time predictions of segmented temperature gradients.

PubMed

Wiese, Steffen; Teutenberg, Thorsten; Schmidt, Torsten C

2012-01-27

In the present work it is shown that the linear elution strength (LES) model which was adapted from temperature-programming gas chromatography (GC) can also be employed for systematic method development in high-temperature liquid chromatography (HT-HPLC). The ability to predict isothermal retention times based on temperature-gradient as well as isothermal input data was investigated. For a small temperature interval of ΔT=40°C, both approaches result in very similar predictions. Average relative errors of predicted retention times of 2.7% and 1.9% were observed for simulations based on isothermal and temperature-gradient measurements, respectively. Concurrently, it was investigated whether the accuracy of retention time predictions of segmented temperature gradients can be further improved by temperature dependent calculation of the parameter S(T) of the LES relationship. It was found that the accuracy of retention time predictions of multi-step temperature gradients can be improved to around 1.5%, if S(T) was also calculated temperature dependent. The adjusted experimental design making use of four temperature-gradient measurements was applied for systematic method development of selected food additives by high-temperature liquid chromatography. Method development was performed within a temperature interval from 40°C to 180°C using water as mobile phase. Two separation methods were established where selected food additives were baseline separated. In addition, a good agreement between simulation and experiment was observed, because an average relative error of predicted retention times of complex segmented temperature gradients less than 5% was observed. Finally, a schedule of recommendations to assist the practitioner during systematic method development in high-temperature liquid chromatography was established. Copyright © 2011 Elsevier B.V. All rights reserved.

Retention of long-term interim restorations with sodium fluoride enriched interim cement

NASA Astrophysics Data System (ADS)

Strash, Carolyn

Purpose: Interim fixed dental prostheses, or "provisional restorations", are fabricated to restore teeth when definitive prostheses are made indirectly. Patients undergoing extensive prosthodontic treatment frequently require provisionalization for several months or years. The ideal interim cement would retain the restoration for as long as needed and still allow for ease of removal. It would also avoid recurrent caries by preventing demineralization of tooth structure. This study aims to determine if adding sodium fluoride varnish to interim cement may assist in the retention of interim restorations. Materials and methods: stainless steel dies representing a crown preparation were fabricated. Provisional crowns were milled for the dies using CAD/CAM technology. Crowns were provisionally cemented onto the dies using TempBond NE and NexTemp provisional cements as well as a mixture of TempBond NE and Duraphat fluoride varnish. Samples were stored for 24h then tested or thermocycled for 2500 or 5000 cycles before being tested. Retentive strength of each cement was recorded using a universal testing machine. Results: TempBond NE and NexTemp cements performed similarly when tested after 24h. The addition of Duraphat significantly decreased the retention when added to TempBond NE. NexTemp cement had high variability in retention over all tested time periods. Thermocycling for 2500 and 5000 cycles significantly decreased the retention of all cements. Conclusions: The addition of Duraphat fluoride varnish significantly decreased the retention of TempBond NE and is therefore not recommended for clinical use. Thermocycling significantly reduced the retention of TempBond NE and NexTemp. This may suggest that use of these cements for three months, as simulated in this study, is not recommended.

Two-dimensional wavelet analysis based classification of gas chromatogram differential mobility spectrometry signals.

PubMed

Zhao, Weixiang; Sankaran, Shankar; Ibáñez, Ana M; Dandekar, Abhaya M; Davis, Cristina E

2009-08-04

This study introduces two-dimensional (2-D) wavelet analysis to the classification of gas chromatogram differential mobility spectrometry (GC/DMS) data which are composed of retention time, compensation voltage, and corresponding intensities. One reported method to process such large data sets is to convert 2-D signals to 1-D signals by summing intensities either across retention time or compensation voltage, but it can lose important signal information in one data dimension. A 2-D wavelet analysis approach keeps the 2-D structure of original signals, while significantly reducing data size. We applied this feature extraction method to 2-D GC/DMS signals measured from control and disordered fruit and then employed two typical classification algorithms to testify the effects of the resultant features on chemical pattern recognition. Yielding a 93.3% accuracy of separating data from control and disordered fruit samples, 2-D wavelet analysis not only proves its feasibility to extract feature from original 2-D signals but also shows its superiority over the conventional feature extraction methods including converting 2-D to 1-D and selecting distinguishable pixels from training set. Furthermore, this process does not require coupling with specific pattern recognition methods, which may help ensure wide applications of this method to 2-D spectrometry data.

Comparative evaluation of border molding using two different techniques in maxillary edentulous arches: A clinical study

PubMed Central

Qanungo, Anchal; Aras, Meena Ajay; Chitre, Vidya; Coutinho, Ivy; Rajagopal, Praveen; Mysore, Ashwin

2016-01-01

Purpose: The aim of this in vivo study was to compare the single-step border molding technique using injectable heavy viscosity addition silicone with sectional border molding technique using low fusing impression compound by evaluating the retention of heat cure trial denture bases. Materials and Methods: Ten completely edentulous patients in need of prostheses were included in this study. Two border molding techniques, single-step (Group 1) and sectional (Group 2), were compared for retention. Both border molding techniques were performed in each patient. In both techniques, definitive wash impression was made with light viscosity addition silicone. The final results were analyzed using paired t-test to determine whether significant differences existed between the groups. Results: The t-value (3.031) infers that there was a significant difference between Group 1 and Group 2 (P = 0.014). The retention obtained in Group 2 (mean = 9.05 kgf) was significantly higher than that of Group 1 (mean = 8.26 kgf). Conclusion: Sectional border molding technique proved to be more retentive as compared to single-step border molding although clinically the retention appeared comparable. PMID:27746597

Comparison of retention models for polymers 1. Poly(ethylene glycol)s.

PubMed

Bashir, Mubasher A; Radke, Wolfgang

2006-10-27

The suitability of three different retention models to predict the retention times of poly(ethylene glycol)s (PEGs) in gradient and isocratic chromatography was investigated. The models investigated were the linear (LSSM) and the quadratic solvent strength model (QSSM). In addition, a model describing the retention behaviour of polymers was extended to account for gradient elution (PM). It was found that all models are suited to properly predict gradient retention volumes provided the extraction of the analyte specific parameters is performed from gradient experiments as well. The LSSM and QSSM on principle cannot describe retention behaviour under critical or SEC conditions. Since the PM is designed to cover all three modes of polymer chromatography, it is therefore superior to the other models. However, the determination of the analyte specific parameters, which are needed to calibrate the retention behaviour, strongly depend on the suitable selection of initial experiments. A useful strategy for a purposeful selection of these calibration experiments is proposed.

Modeling the retention of rumen boluses for the electronic identification of goats.

PubMed

Carné, S; Caja, G; Ghirardi, J J; Salama, A A K

2011-02-01

We constructed a regression model to estimate the retention of electronic boluses in goats. With this aim, 2,482 boluses were administered to goats from dairy (Murciano-Granadina, n=1,326; French Alpine, n=381) and meat (Blanca de Rasquera, n=532) breeds. A total of 19 bolus types made of materials (ceramic, plastic tubes filled with concrete or silicone, and ballasts) differing in their specific gravity (SG) were used, thereby obtaining a wide variation in bolus features: diameter (9 to 22 mm), length (37 to 84 mm), weight (5 to 111 g), volume (2.6 to 26 mL), and SG (1.0 to 5.5). Each bolus contained a half-duplex glass encapsulated transponder (32 × 3.8mm) and was administered using adapted balling guns. Murciano-Granadina and Blanca de Rasquera goats also wore 2 visual plastic ear tags: V1 (double flag, 5.1g) and V2 (flag-button, 4.2g). No data on ear tags in French Alpine goats was available. Bolus and ear tag retention [(retained/monitored) × 100] was recorded for at least 1 yr. Dynamic reading efficiency [(dynamic reading/static reading) × 100] was also evaluated from 1,496 bolus readings. No administration incidences or apparent negative behavior or performance effects were observed for any bolus type. Static reading efficiency of retained boluses was 100%, except for the prototypes with metal ballasts, which yielded a 93.3% reading efficiency. Retention of metal-ballasted boluses was confirmed using x-ray equipment. Excluding ballasted boluses, a 99.5% dynamic reading efficiency was obtained. Ear tag losses were 6.5% for V1 and 3.7% for V2, ranging from 3.2 to 7.8% depending on ear tag type and goat breed. Bolus retention varied (0 to 100%) according to their physical features. Obtained data allowed the fitting of a logistic model of bolus retention rate according to bolus volume and weight (R(2) = 0.98); the SG was implicitly considered. Estimated weight and SG to produce medium- (15 mL) and standard-sized (22 mL) boluses for 99.95% retention rate in goats were 73.0 and 94.1g, and 4.87 and 4.28, respectively. Mini-boluses are not recommended, as none of the available radio translucent materials reach the required SG. In conclusion, increase of SG was fundamental to optimize bolus retention. Medium-sized boluses (10 to 15 mL; SG 5.8 to 4.9) for early administration and efficient retention in adult goats could be produced, thereby addressing the problem of using proper boluses for goat identification. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Online Actions with Offline Impact: How Online Social Networks Influence Online and Offline User Behavior.

PubMed

Althoff, Tim; Jindal, Pranav; Leskovec, Jure

2017-02-01

Many of today's most widely used computing applications utilize social networking features and allow users to connect, follow each other, share content, and comment on others' posts. However, despite the widespread adoption of these features, there is little understanding of the consequences that social networking has on user retention, engagement, and online as well as offline behavior. Here, we study how social networks influence user behavior in a physical activity tracking application. We analyze 791 million online and offline actions of 6 million users over the course of 5 years, and show that social networking leads to a significant increase in users' online as well as offline activities. Specifically, we establish a causal effect of how social networks influence user behavior. We show that the creation of new social connections increases user online in-application activity by 30%, user retention by 17%, and user offline real-world physical activity by 7% (about 400 steps per day). By exploiting a natural experiment we distinguish the effect of social influence of new social connections from the simultaneous increase in user's motivation to use the app and take more steps. We show that social influence accounts for 55% of the observed changes in user behavior, while the remaining 45% can be explained by the user's increased motivation to use the app. Further, we show that subsequent, individual edge formations in the social network lead to significant increases in daily steps. These effects diminish with each additional edge and vary based on edge attributes and user demographics. Finally, we utilize these insights to develop a model that accurately predicts which users will be most influenced by the creation of new social network connections.

Online Actions with Offline Impact: How Online Social Networks Influence Online and Offline User Behavior

PubMed Central

Althoff, Tim; Jindal, Pranav; Leskovec, Jure

2017-01-01

Many of today’s most widely used computing applications utilize social networking features and allow users to connect, follow each other, share content, and comment on others’ posts. However, despite the widespread adoption of these features, there is little understanding of the consequences that social networking has on user retention, engagement, and online as well as offline behavior. Here, we study how social networks influence user behavior in a physical activity tracking application. We analyze 791 million online and offline actions of 6 million users over the course of 5 years, and show that social networking leads to a significant increase in users’ online as well as offline activities. Specifically, we establish a causal effect of how social networks influence user behavior. We show that the creation of new social connections increases user online in-application activity by 30%, user retention by 17%, and user offline real-world physical activity by 7% (about 400 steps per day). By exploiting a natural experiment we distinguish the effect of social influence of new social connections from the simultaneous increase in user’s motivation to use the app and take more steps. We show that social influence accounts for 55% of the observed changes in user behavior, while the remaining 45% can be explained by the user’s increased motivation to use the app. Further, we show that subsequent, individual edge formations in the social network lead to significant increases in daily steps. These effects diminish with each additional edge and vary based on edge attributes and user demographics. Finally, we utilize these insights to develop a model that accurately predicts which users will be most influenced by the creation of new social network connections. PMID:28345078

Increased Alpha-Band Power during the Retention of Shapes and Shape-Location Associations in Visual Short-Term Memory

PubMed Central

Johnson, Jeffrey S.; Sutterer, David W.; Acheson, Daniel J.; Lewis-Peacock, Jarrod A.; Postle, Bradley R.

2011-01-01

Studies exploring the role of neural oscillations in cognition have revealed sustained increases in alpha-band (~8–14 Hz) power during the delay period of delayed-recognition short-term memory tasks. These increases have been proposed to reflect the inhibition, for example, of cortical areas representing task-irrelevant information, or of potentially interfering representations from previous trials. Another possibility, however, is that elevated delay-period alpha-band power (DPABP) reflects the selection and maintenance of information, rather than, or in addition to, the inhibition of task-irrelevant information. In the present study, we explored these possibilities using a delayed-recognition paradigm in which the presence and task relevance of shape information was systematically manipulated across trial blocks and electroencephalographic was used to measure alpha-band power. In the first trial block, participants remembered locations marked by identical black circles. The second block featured the same instructions, but locations were marked by unique shapes. The third block featured the same stimulus presentation as the second, but with pretrial instructions indicating, on a trial-by-trial basis, whether memory for shape or location was required, the other dimension being irrelevant. In the final block, participants remembered the unique pairing of shape and location for each stimulus. Results revealed minimal DPABP in each of the location-memory conditions, whether locations were marked with identical circles or with unique task-irrelevant shapes. In contrast, alpha-band power increases were observed in both the shape-memory condition, in which location was task irrelevant, and in the critical final condition, in which both shape and location were task relevant. These results provide support for the proposal that alpha-band oscillations reflect the retention of shape information and/or shape–location associations in short-term memory. PMID:21713012

The specification and global reprogramming of histone epigenetic marks during gamete formation and early embryo development in C. elegans.

PubMed

Samson, Mark; Jow, Margaret M; Wong, Catherine C L; Fitzpatrick, Colin; Aslanian, Aaron; Saucedo, Israel; Estrada, Rodrigo; Ito, Takashi; Park, Sung-kyu Robin; Yates, John R; Chu, Diana S

2014-10-01

In addition to the DNA contributed by sperm and oocytes, embryos receive parent-specific epigenetic information that can include histone variants, histone post-translational modifications (PTMs), and DNA methylation. However, a global view of how such marks are erased or retained during gamete formation and reprogrammed after fertilization is lacking. To focus on features conveyed by histones, we conducted a large-scale proteomic identification of histone variants and PTMs in sperm and mixed-stage embryo chromatin from C. elegans, a species that lacks conserved DNA methylation pathways. The fate of these histone marks was then tracked using immunostaining. Proteomic analysis found that sperm harbor ∼2.4 fold lower levels of histone PTMs than embryos and revealed differences in classes of PTMs between sperm and embryos. Sperm chromatin repackaging involves the incorporation of the sperm-specific histone H2A variant HTAS-1, a widespread erasure of histone acetylation, and the retention of histone methylation at sites that mark the transcriptional history of chromatin domains during spermatogenesis. After fertilization, we show HTAS-1 and 6 histone PTM marks distinguish sperm and oocyte chromatin in the new embryo and characterize distinct paternal and maternal histone remodeling events during the oocyte-to-embryo transition. These include the exchange of histone H2A that is marked by ubiquitination, retention of HTAS-1, removal of the H2A variant HTZ-1, and differential reprogramming of histone PTMs. This work identifies novel and conserved features of paternal chromatin that are specified during spermatogenesis and processed in the embryo. Furthermore, our results show that different species, even those with diverged DNA packaging and imprinting strategies, use conserved histone modification and removal mechanisms to reprogram epigenetic information.

Strategies to improve retention in randomised trials.

PubMed

Brueton, Valerie C; Tierney, Jayne; Stenning, Sally; Harding, Seeromanie; Meredith, Sarah; Nazareth, Irwin; Rait, Greta

2013-12-03

Loss to follow-up from randomised trials can introduce bias and reduce study power, affecting the generalisability, validity and reliability of results. Many strategies are used to reduce loss to follow-up and improve retention but few have been formally evaluated. To quantify the effect of strategies to improve retention on the proportion of participants retained in randomised trials and to investigate if the effect varied by trial strategy and trial setting. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PreMEDLINE, EMBASE, PsycINFO, DARE, CINAHL, Campbell Collaboration's Social, Psychological, Educational and Criminological Trials Register, and ERIC. We handsearched conference proceedings and publication reference lists for eligible retention trials. We also surveyed all UK Clinical Trials Units to identify further studies. We included eligible retention trials of randomised or quasi-randomised evaluations of strategies to increase retention that were embedded in 'host' randomised trials from all disease areas and healthcare settings. We excluded studies aiming to increase treatment compliance. We contacted authors to supplement or confirm data that we had extracted. For retention trials, we recorded data on the method of randomisation, type of strategy evaluated, comparator, primary outcome, planned sample size, numbers randomised and numbers retained. We used risk ratios (RR) to evaluate the effectiveness of the addition of strategies to improve retention. We assessed heterogeneity between trials using the Chi(2) and I(2) statistics. For main trials that hosted retention trials, we extracted data on disease area, intervention, population, healthcare setting, sequence generation and allocation concealment. We identified 38 eligible retention trials. Included trials evaluated six broad types of strategies to improve retention. These were incentives, communication strategies, new questionnaire format, participant case management, behavioural and methodological interventions. For 34 of the included trials, retention was response to postal and electronic questionnaires with or without medical test kits. For four trials, retention was the number of participants remaining in the trial. Included trials were conducted across a spectrum of disease areas, countries, healthcare and community settings. Strategies that improved trial retention were addition of monetary incentives compared with no incentive for return of trial-related postal questionnaires (RR 1.18; 95% CI 1.09 to 1.28, P value < 0.0001), addition of an offer of monetary incentive compared with no offer for return of electronic questionnaires (RR 1.25; 95% CI 1.14 to 1.38, P value < 0.00001) and an offer of a GBP20 voucher compared with GBP10 for return of postal questionnaires and biomedical test kits (RR 1.12; 95% CI 1.04 to 1.22, P value < 0.005). The evidence that shorter questionnaires are better than longer questionnaires was unclear (RR 1.04; 95% CI 1.00 to 1.08, P value = 0.07) and the evidence for questionnaires relevant to the disease/condition was also unclear (RR 1.07; 95% CI 1.01 to 1.14). Although each was based on the results of a single trial, recorded delivery of questionnaires seemed to be more effective than telephone reminders (RR 2.08; 95% CI 1.11 to 3.87, P value = 0.02) and a 'package' of postal communication strategies with reminder letters appeared to be better than standard procedures (RR 1.43; 95% CI 1.22 to 1.67, P value < 0.0001). An open trial design also appeared more effective than a blind trial design for return of questionnaires in one fracture prevention trial (RR 1.37; 95% CI 1.16 to 1.63, P value = 0.0003).There was no good evidence that the addition of a non-monetary incentive, an offer of a non-monetary incentive, 'enhanced' letters, letters delivered by priority post, additional reminders, or questionnaire question order either increased or decreased trial questionnaire response/retention. There was also no evidence that a telephone survey was either more or less effective than a monetary incentive and a questionnaire. As our analyses are based on single trials, the effect on questionnaire response of using offers of charity donations, sending reminders to trial sites and when a questionnaire is sent, may need further evaluation. Case management and behavioural strategies used for trial retention may also warrant further evaluation. Most of the retention trials that we identified evaluated questionnaire response. There were few evaluations of ways to improve participants returning to trial sites for trial follow-up. Monetary incentives and offers of monetary incentives increased postal and electronic questionnaire response. Some other strategies evaluated in single trials looked promising but need further evaluation. Application of the findings of this review would depend on trial setting, population, disease area, data collection and follow-up procedures.

Strategies to enhance patient recruitment and retention in research involving patients with a first episode of mental illness.

PubMed

Furimsky, Ivana; Cheung, Amy H; Dewa, Carolyn S; Zipursky, Robert B

2008-11-01

Recruitment and retention of research participants is often the most labor-intensive and difficult component of clinical trials. Poor recruitment and retention frequently pose as a major barrier in the successful completion of clinical trials. In fact, many studies are prematurely terminated, or their findings questioned due to low recruitment and retention rates. The conduct of clinical trials involving youth with a first episode of mental illness comes with additional challenges in recruitment and retention including barriers associated with engagement and family involvement. To develop effective early interventions for first episode mental illness, it is necessary to develop strategies to enhance recruitment and retention in this patient population. This article presents the recruitment and retention challenges experienced in two clinical trials: one involving participants experiencing a first episode of depression and one involving participants experiencing a first episode psychosis. Challenges with recruitment and retention are identified and reviewed at both the patient level and clinician level. Strategies that were implemented to enhance recruitment and retention in these two studies are also discussed. Finally, ethical issues to consider when implementing these strategies are also highlighted.

Combined effects of mobile phase composition and temperature on the retention of phenolic antioxidants on an octylsilica polydentate column.

PubMed

Jandera, Pavel; Vyňuchalová, Kateřina; Nečilová, Kateřina

2013-11-22

Combined effects of temperature and mobile-phase composition on retention and separation selectivity of phenolic acids and flavonoid compounds were studied in liquid chromatography on a polydentate Blaze C8 silica based column. The temperature effects on the retention can be described by van't Hoff equation. Good linearity of lnk versus 1/T graphs indicates that the retention is controlled by a single mechanism in the mobile phase and temperature range studied. Enthalpic and entropic contributions to the retention were calculated from the regression lines. Generally, enthalpic contributions control the retention at lower temperatures and in mobile phases with lower concentrations of methanol in water. Semi-empirical retention models describe the simultaneous effects of temperature and the volume fraction of the organic solvent in the mobile phase. Using the linear free energy-retention model, selective dipolarity/polarizability, hydrogen-bond donor, hydrogen-bond acceptor and molecular size contributions to retention were estimated at various mobile phase compositions and temperatures. In addition to mobile phase gradients, temperature programming can be used to reduce separation times. Copyright © 2013 Elsevier B.V. All rights reserved.

Management of postoperative urinary retention: a randomized trial of in-out versus overnight catheterization.

PubMed

Lau, Hung; Lam, Becky

2004-08-01

There has been no consensus on the best catheterization strategy for the management of postoperative urinary retention. A prospective randomized trial was undertaken to establish the best practice guidelines for the management of postoperative urinary retention. The authors also evaluated the contemporary incidence of urinary retention following different categories of general surgery and examined risk factors associated with its occurrence. All patients who underwent elective inpatient surgery between January 2002 and June 2003 were recruited into the study. Patients who developed postoperative urinary retention were randomized to either having in-out catheterization or placement of an indwelling catheter for 24 h after surgery. A total of 1448 patients was recruited. The overall incidence of urinary retention was 4.1% (n = 60). Significant risk factors associated with postoperative urinary retention included old age, anorectal procedures and use of spinal anaesthesia. Comparison of re-catheterization and urinary tract infection rates between patients who were treated with in-out versus overnight catheterization found no significant differences. Postoperative urinary retention should be managed by in-out catheterization. Indwelling catheterization for 24 h appeared to bestow no additional benefits. The incidence of urinary retention increases with age, anorectal procedures and the use of spinal anaesthesia.

MetMatch: A Semi-Automated Software Tool for the Comparison and Alignment of LC-HRMS Data from Different Metabolomics Experiments

PubMed Central

Koch, Stefan; Bueschl, Christoph; Doppler, Maria; Simader, Alexandra; Meng-Reiterer, Jacqueline; Lemmens, Marc; Schuhmacher, Rainer

2016-01-01

Due to its unsurpassed sensitivity and selectivity, LC-HRMS is one of the major analytical techniques in metabolomics research. However, limited stability of experimental and instrument parameters may cause shifts and drifts of retention time and mass accuracy or the formation of different ion species, thus complicating conclusive interpretation of the raw data, especially when generated in different analytical batches. Here, a novel software tool for the semi-automated alignment of different measurement sequences is presented. The tool is implemented in the Java programming language, it features an intuitive user interface and its main goal is to facilitate the comparison of data obtained from different metabolomics experiments. Based on a feature list (i.e., processed LC-HRMS chromatograms with mass-to-charge ratio (m/z) values and retention times) that serves as a reference, the tool recognizes both m/z and retention time shifts of single or multiple analytical datafiles/batches of interest. MetMatch is also designed to account for differently formed ion species of detected metabolites. Corresponding ions and metabolites are matched and chromatographic peak areas, m/z values and retention times are combined into a single data matrix. The convenient user interface allows for easy manipulation of processing results and graphical illustration of the raw data as well as the automatically matched ions and metabolites. The software tool is exemplified with LC-HRMS data from untargeted metabolomics experiments investigating phenylalanine-derived metabolites in wheat and T-2 toxin/HT-2 toxin detoxification products in barley. PMID:27827849

MetMatch: A Semi-Automated Software Tool for the Comparison and Alignment of LC-HRMS Data from Different Metabolomics Experiments.

PubMed

Koch, Stefan; Bueschl, Christoph; Doppler, Maria; Simader, Alexandra; Meng-Reiterer, Jacqueline; Lemmens, Marc; Schuhmacher, Rainer

2016-11-02

Due to its unsurpassed sensitivity and selectivity, LC-HRMS is one of the major analytical techniques in metabolomics research. However, limited stability of experimental and instrument parameters may cause shifts and drifts of retention time and mass accuracy or the formation of different ion species, thus complicating conclusive interpretation of the raw data, especially when generated in different analytical batches. Here, a novel software tool for the semi-automated alignment of different measurement sequences is presented. The tool is implemented in the Java programming language, it features an intuitive user interface and its main goal is to facilitate the comparison of data obtained from different metabolomics experiments. Based on a feature list (i.e., processed LC-HRMS chromatograms with mass-to-charge ratio ( m / z ) values and retention times) that serves as a reference, the tool recognizes both m / z and retention time shifts of single or multiple analytical datafiles/batches of interest. MetMatch is also designed to account for differently formed ion species of detected metabolites. Corresponding ions and metabolites are matched and chromatographic peak areas, m / z values and retention times are combined into a single data matrix. The convenient user interface allows for easy manipulation of processing results and graphical illustration of the raw data as well as the automatically matched ions and metabolites. The software tool is exemplified with LC-HRMS data from untargeted metabolomics experiments investigating phenylalanine-derived metabolites in wheat and T-2 toxin/HT-2 toxin detoxification products in barley.

QSRR modeling for the chromatographic retention behavior of some β-lactam antibiotics using forward and firefly variable selection algorithms coupled with multiple linear regression.

PubMed

Fouad, Marwa A; Tolba, Enas H; El-Shal, Manal A; El Kerdawy, Ahmed M

2018-05-11

The justified continuous emerging of new β-lactam antibiotics provokes the need for developing suitable analytical methods that accelerate and facilitate their analysis. A face central composite experimental design was adopted using different levels of phosphate buffer pH, acetonitrile percentage at zero time and after 15 min in a gradient program to obtain the optimum chromatographic conditions for the elution of 31 β-lactam antibiotics. Retention factors were used as the target property to build two QSRR models utilizing the conventional forward selection and the advanced nature-inspired firefly algorithm for descriptor selection, coupled with multiple linear regression. The obtained models showed high performance in both internal and external validation indicating their robustness and predictive ability. Williams-Hotelling test and student's t-test showed that there is no statistical significant difference between the models' results. Y-randomization validation showed that the obtained models are due to significant correlation between the selected molecular descriptors and the analytes' chromatographic retention. These results indicate that the generated FS-MLR and FFA-MLR models are showing comparable quality on both the training and validation levels. They also gave comparable information about the molecular features that influence the retention behavior of β-lactams under the current chromatographic conditions. We can conclude that in some cases simple conventional feature selection algorithm can be used to generate robust and predictive models comparable to that are generated using advanced ones. Copyright © 2018 Elsevier B.V. All rights reserved.

Oxygen plasma immersion ion implantation treatment to enhance data retention of tungsten nanocrystal nonvolatile memory

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

Wang, Jer-Chyi, E-mail: jcwang@mail.cgu.edu.tw; Chang, Wei-Cheng; Lai, Chao-Sung, E-mail: cslai@mail.cgu.edu.tw

Data retention characteristics of tungsten nanocrystal (W-NC) memory devices using an oxygen plasma immersion ion implantation (PIII) treatment are investigated. With an increase of oxygen PIII bias voltage and treatment time, the capacitance–voltage hysteresis memory window is increased but the data retention characteristics become degraded. High-resolution transmission electron microscopy images show that this poor data retention is a result of plasma damage on the tunneling oxide layer, which can be prevented by lowering the bias voltage to 7 kV. In addition, by using the elevated temperature retention measurement technique, the effective charge trapping level of the WO{sub 3} film surrounding themore » W-NCs can be extracted. This measurement reveals that a higher oxygen PIII bias voltage and treatment time induces more shallow traps within the WO{sub 3} film, degrading the retention behavior of the W-NC memory.« less

The effect of amino acid lysine and methionine addition on feed toward the growth and retention on mud crab (Scylla serrata)

NASA Astrophysics Data System (ADS)

Alissianto, Y. R.; Sandriani, Z. A.; Rahardja, B. S.; Agustono; Rozi

2018-04-01

High market demand of mud crab (Scylla serrata) encourages farmers to increase the production of mud crab. However, mud crab can not synthesize essential amino acids, so it is necessary to supply essential amino acids such as lysine and methionine in the diet. This study aims to determine the effect of lysine and methionine on feeds to increase growth and retention of mud crabs (Scylla serrata). In this study the amount of lysine amino acid and methionine added to the trash fish diet were: P0 (0: 0%); P1 (0.75: 0.75%); P2 (1: 1%); P3 (1.25: 1.25%); P4 (1.5: 1.5%) with the ratio of lysine and methionine 1: 1. The parameters observed in this study were Survival Rate (SR), Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Efficiency Feed (EF), protein retention and energy retention. The results of the 35-day maintenance study showed significant differences (P <0.05) against Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Efficiency Feed (EF), protein retention and no significant effect (P> 0.05) on energy retention and Survival Rate (SR) on mud crab. The best results in this study were found in P4 treatment with addition of lysine amino acids and methionine (1.5: 1.5%).

Effects of bilateral caloric habituation of nystagmus responses of the cat.

DOT National Transportation Integrated Search

1964-09-01

It has been suggested that the decline (habituation) of the nystagmus response to repeated vestibular stimulation is a form of learning in that it possesses the necessary features of learned behavior - acquisition, retention, and transfer.

78 FR 57927 - Credit Risk Retention

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-20

..., Division of Research & Statistics, (202) 452-2342; or Nikita Pastor, Counsel, (202) 452-3667, Division of... include provisions that strengthen the regulation and supervision of national recognized statistical... delinquencies and foreclosures since 2007. These included features permitting negative amortization, interest...

Robust memory of where from way back when: evidence from behaviour and visual attention.

PubMed

Bauer, Patricia J; Stewart, Rebekah; Sirkin, Ruth E; Larkina, Marina

2017-09-01

Retention of events typically exhibits a sharp initial decrease followed by levelling off of forgetting. In an apparent exception to this general rule, college students have robust memory for their own locations in obscured versions of photographs of their entering classes taken during orientation-related activities, whether tested 2 months or 42 months after the event. Experiment 1 of the present research was a test for conceptual replication of this finding in photographs depicting more than twice the number of students (and thus potential distracters). There was no difference in memory accuracy for personal spatial location across retention intervals of 6-30 months. Experiment 2 featured 40-h and 2-month retention intervals, thereby providing a more fine-grained test of the forgetting function. The findings replicated Experiment 1. In Experiment 3, eye-tracking measures of visual attention revealed that participants rapidly fixated their own spatial locations within the photographs, even in the absence of explicit awareness. In all three experiments, memory for temporal features of the orientation activities (e.g., day and time the photograph was taken) followed the typical forgetting function. The findings suggest differential preservation of episodic memory for where relative to other aspects of events and experiences, such as when.

FDT 2.0: Improving scalability of the fuzzy decision tree induction tool - integrating database storage.

PubMed

Durham, Erin-Elizabeth A; Yu, Xiaxia; Harrison, Robert W

2014-12-01

Effective machine-learning handles large datasets efficiently. One key feature of handling large data is the use of databases such as MySQL. The freeware fuzzy decision tree induction tool, FDT, is a scalable supervised-classification software tool implementing fuzzy decision trees. It is based on an optimized fuzzy ID3 (FID3) algorithm. FDT 2.0 improves upon FDT 1.0 by bridging the gap between data science and data engineering: it combines a robust decisioning tool with data retention for future decisions, so that the tool does not need to be recalibrated from scratch every time a new decision is required. In this paper we briefly review the analytical capabilities of the freeware FDT tool and its major features and functionalities; examples of large biological datasets from HIV, microRNAs and sRNAs are included. This work shows how to integrate fuzzy decision algorithms with modern database technology. In addition, we show that integrating the fuzzy decision tree induction tool with database storage allows for optimal user satisfaction in today's Data Analytics world.

Is there a crisis in nursing retention in New South Wales?

PubMed Central

Doiron, Denise; Hall, Jane; Jones, Glenn

2008-01-01

Background There is a severe shortage of nurses in Australia. Policy makers and researchers are especially concerned that retention levels of nurses in the health workforce have worsened over the last decade. There are also concerns that rapidly growing private sector hospitals are attracting qualified nurses away from the public sector. To date no systematic analysis of trends in nursing retention rates over time has been conducted due to the lack of consistent panel data. Results A 1.4 percentage point improvement in retention has led to a 10% increase in the overall supply of nurses in NSW. There has also been a substantial aging of the workforce, due to greater retention and an increase in mature age entrants. The improvement in retention is found in all types of premises and is largest in nursing homes. There is a substantial amount of year to year movement in and out of the workforce and across premises. The shortage of nurses in public hospitals is due to a slowdown in entry rather than competition from the rapidly growing private sector hospitals. Policy Implications The finding of an improvement (rather than a worsening) in retention suggests that additional improvements may be difficult to achieve as further retention must involve individuals more and more dissatisfied with nursing relative to other opportunities. Hence policies targeting entry such as increased places in nursing programs and additional subsidies for training costs may be more effective in dealing with the workforce shortage. This is also the case for shortages in public sector hospitals as retention in nursing is found to be relatively high in this sector. However, the large amount of year to year movements across nursing jobs, especially among the younger nurses, also suggests that policies aimed at reducing job switches and increasing the number who return to nursing should also be pursued. More research is needed in understanding the relative importance of detailed working conditions and the problems associated with combining family responsibilities and nursing jobs. PMID:18681970

General experiences + race + racism = Work lives of Black faculty in postsecondary science education

NASA Astrophysics Data System (ADS)

Parsons, Eileen R. C.; Bulls, Domonique L.; Freeman, Tonjua B.; Butler, Malcolm B.; Atwater, Mary M.

2016-12-01

Existent research indicates that postsecondary Black faculty members, who are sorely underrepresented in the academy especially in STEM fields, assume essential roles; chief among these roles is diversifying higher education. Their recruitment and retention become more challenging in light of research findings on work life for postsecondary faculty. Research has shown that postsecondary faculty members in general have become increasingly stressed and job satisfaction has declined with dissatisfaction with endeavors and work overload cited as major stressors. In addition to the stresses managed by higher education faculty at large, Black faculty must navigate diversity-related challenges. Illuminating and understanding their experiences can be instrumental in lessening stress and job dissatisfaction, outcomes that facilitate recruitment and retention. This study featured the experiences and perceptions of Black faculty in science education. This study, framed by critical race theory, examines two questions: What characterizes the work life of some Black faculty members who teach, research, and serve in science education? How are race and racism present in the experiences of these postsecondary Black faculty members? A phenomenological approach to the study situates the experiences of the Black participants as valid phenomena worthy of investigation, illuminates their experiences, and seeks to retain the authenticity of their voices.

24 CFR 990.305 - Retention of excess revenues.

Code of Federal Regulations, 2010 CFR

2010-04-01

... business enterprises that employ residents of public housing, or acquiring additional dwelling units for... Resident Management Corporations (RMCs) § 990.305 Retention of excess revenues. (a) Any income generated by an RMC that exceeds the income estimated for the income categories specified in the RMC's management...

Optimization of the Use of Selected Non-Phosphate Water Retention Additives in Minced Beef Using Response Surface Methodology

NASA Astrophysics Data System (ADS)

Shang, Xiaolan; Qiao, Jie; Liu, Yujie

2017-12-01

This study looked to determine what the optimum cooking loss for minced beef was when three different non-phosphate water retention additives (L-Arginine, sodium carbonate, and sodium citrate) were combined; the optimum value was determined using a Box-Behnken response surface design method. The optimum value was found to be 8.26%, and it was obtained when 0.29% L-Arginine, 0.45% sodium carbonate, and 0.24% sodium citrate were added to the beef.

A 12-week commercial web-based weight-loss program for overweight and obese adults: randomized controlled trial comparing basic versus enhanced features.

PubMed

Collins, Clare E; Morgan, Philip J; Jones, Penelope; Fletcher, Kate; Martin, Julia; Aguiar, Elroy J; Lucas, Ashlee; Neve, Melinda J; Callister, Robin

2012-04-25

The development and use of Web-based programs for weight loss is increasing rapidly, yet they have rarely been evaluated using randomized controlled trials (RCTs). Interestingly, most people who attempt weight loss use commercially available programs, yet it is very uncommon for commercial programs to be evaluated independently or rigorously. To compare the efficacy of a standard commercial Web-based weight-loss program (basic) versus an enhanced version of this Web program that provided additional personalized e-feedback and contact from the provider (enhanced) versus a wait-list control group (control) on weight outcomes in overweight and obese adults. This purely Web-based trial using a closed online user group was an assessor-blinded RCT with participants randomly allocated to the basic or enhanced 12-week Web-based program, based on social cognitive theory, or the control, with body mass index (BMI) as the primary outcome. We enrolled 309 adults (129/309, 41.8% male, BMI mean 32.3, SD 4 kg/m(2)) with 84.1% (260/309) retention at 12 weeks. Intention-to-treat analysis showed that both intervention groups reduced their BMI compared with the controls (basic: -0.72, SD 1.1 kg/m(2), enhanced: -1.0, SD 1.4, control: 0.15, SD 0.82; P < .001) and lost significant weight (basic: -2.1, SD 3.3 kg, enhanced: -3.0, SD 4.1, control: 0.4, SD 2.3; P < .001) with changes in waist circumference (basic: -2.0, SD 3.5 cm, enhanced: -3.2, SD 4.7, control: 0.5, SD 3.0; P < .001) and waist-to-height ratio (basic: -0.01, SD 0.02, enhanced: -0.02, SD 0.03, control: 0.0, SD 0.02; P < .001), but no differences were observed between the basic and enhanced groups. The addition of personalized e-feedback and contact provided limited additional benefits compared with the basic program. A commercial Web-based weight-loss program can be efficacious across a range of weight-related outcomes and lifestyle behaviors and achieve clinically important weight loss. Although the provision of additional personalized feedback did not facilitate greater weight loss after 12 weeks, the impact of superior participant retention on longer-term outcomes requires further study. Further research is required to determine the optimal mix of program features that lead to the biggest treatment impact over time. Australian New Zealand Clinical Trials Registry (ANZCTR): 12610000197033.

Developmental Brain Research with Participants from Underprivileged Communities: Strategies for Recruitment, Participation, and Retention

ERIC Educational Resources Information Center

Habibi, Assal; Sarkissian, Alissa Der; Gomez, Martha; Ilari, Beatriz

2015-01-01

Challenges associated with recruitment and retention of participants from underprivileged social communities, in addition to neuroscience researchers' unfamiliarity with these communities, possibly explain the limited number of individuals from these communities who participate in neuroscience research studies. The consequence is a scarcity of…

Revisiting the impact of mobile phone screen size on user comprehension of health information.

PubMed

Alghamdi, Ebtisam; Yunus, Faisel; Househ, Mowafa

2014-01-01

Abstract goes here. This is completion of the research and update of the previous work that was published in 2013[1]. The paper describes our recent experimental study of the impact of mobile screen size on the user comprehension of health information and application structures. An experiment was conducted to measure the impact of screen size on user comprehension and retention. Participants were given the same simple scenario, which consisted of searching from different menus, navigating and reading some contents. They were timed and tracked for correctness. Also, a follow-up survey was given to each participant that consisted of a rating scale to assess usability features, comprehension and retention abilities of the participants based on different mobile screen sizes. Results showed that there was a significant difference between mobile phone screen size and the time taken to read the contents, which was at its highest on small screens (p-value=0.02). Also, reading characters was hardest on a small screen (p-value=0.003). In addition, there was a significant difference between the three screen sizes regarding the organization of the application's information, showing that the smaller the screen size, the more organized the information. On the other hand, there was no significant impact of screen size on user comprehension, retention scores, number of errors or effective task completion but it was generally better if a large screen size was used. This study concludes that the screen size is not the main concern in comprehension of the contents or application structure. However, reading speed improves with the larger screen size and positively influences the task completion and understanding of the application elements.

Sustainable student retention and gender issues in mathematics for ICT study

NASA Astrophysics Data System (ADS)

Divjak, Blazenka; Ostroski, Mirela; Vidacek Hains, Violeta

2010-04-01

This article reports on the research whose specific objective is to improve student retention in mathematics included in the first-year ICT study programme by means of improving teaching methods, with an emphasis on gender issues. Two principal reasons for this research are, first, the fact that first-year mathematics courses are often viewed as an obstacle for retention in studying ICT, and second, the fact that female students are strongly underrepresented in ICT. Furthermore, according to recently introduced research, changes in pedagogy and the content of mathematics have been evaluated. Those changes are directed towards competency-based and student-centred education and are heavily supported by technology-based learning. Although only minor gender differences in different skills have been detected, the pass rate for female students is constantly higher than that for male students. Therefore, the reasons for the better performance of female students have been investigated taking into account both the motivation for study and learning styles. The primary sources of data used in the first year of research comprised questionnaires (n = 130) together with classroom and on-line assessment material for 263 students. In the next year, 160 students of Information Systems participated in the survey, the central topic of which was the motivation for study. Additionally, the research focused on finding out if the motivation factors are gender specific. The research was conducted in Croatia where no research on a similar topic had been previously available. In terms of the specific features of the socio-cultural environment, conducting such a research in Croatia proved to be worthwhile, particularly considering the possibility of comparing the obtained results with those arising from other environments.

Molecular scale modeling of polymer imprint nanolithography.

PubMed

Chandross, Michael; Grest, Gary S

2012-01-10

We present the results of large-scale molecular dynamics simulations of two different nanolithographic processes, step-flash imprint lithography (SFIL), and hot embossing. We insert rigid stamps into an entangled bead-spring polymer melt above the glass transition temperature. After equilibration, the polymer is then hardened in one of two ways, depending on the specific process to be modeled. For SFIL, we cross-link the polymer chains by introducing bonds between neighboring beads. To model hot embossing, we instead cool the melt to below the glass transition temperature. We then study the ability of these methods to retain features by removing the stamps, both with a zero-stress removal process in which stamp atoms are instantaneously deleted from the system as well as a more physical process in which the stamp is pulled from the hardened polymer at fixed velocity. We find that it is necessary to coat the stamp with an antifriction coating to achieve clean removal of the stamp. We further find that a high density of cross-links is necessary for good feature retention in the SFIL process. The hot embossing process results in good feature retention at all length scales studied as long as coated, low surface energy stamps are used.

[Urological emergencies at the Dakar university teaching hospital: epidemiological, clinical and therapeutic features].

PubMed

Fall, B; Diao, B; Fall, P A; Diallo, Y; Sow, Y; Ondongo, A A M; Diagana, M; Ndoye, A K; Ba, M; Diagne, B A

2008-11-01

To present the epidemiological, clinical and therapeutic features of the urological emergencies in Senegal, West Africa. The authors conducted a 20 months retrospective study that analyzed the epidemiological, clinical and therapeutic features of all urological emergencies admitted to the urology department of the university teaching hospital Aristide-Le-Dantec (Dakar). There were 1237 urological emergencies. The mean age of the patients was 58.8 years (range one month-94 years). The sex ratio (M/F) was 20.32. These patients had an age equal to or higher than 60 years in 50.7% of the cases. The most frequent illness was urinary retention (53%) and genitor-urinary system infectious, which represented as a whole 16.4% of the cases. The gangrenes of male external genitalia (Fournier's gangrene) accounted for 4.1% of the cases and the priapism 1.3%. In emergency, 331 surgical operations were performed. The most performed procedures were the installation of a suprapubic catheter (59.8%) and debridement of a gangrene of male external genitalia (15.4%). The most frequent urological emergency in our country was the acute urinary retention. Some serious illness like gangrene of male external genitalia (Fournier's gangrene) and priapism are not rare there.

Assessment of nurse retention challenges and strategies in Lebanese hospitals: the perspective of nursing directors.

PubMed

El-Jardali, Fadi; Merhi, Mirvat; Jamal, Diana; Dumit, Nuhad; Mouro, Gladys

2009-05-01

Assess nurse retention challenges and strategies as perceived by nursing directors in Lebanese hospitals. The Kampala Health Workforce Declaration stressed the importance of retaining an effective, responsive and equitably distributed health workforce, particularly nurses. Little is known about nurse retention challenges and strategies in Lebanon. Nursing directors of 76 hospitals participated and were sent a two-page survey on perceived retention challenges and hospital-based retention strategies. Retention challenges included unsatisfactory salary, unsuitable shifts and working hours, as well as better opportunities in other areas within or outside Lebanon. Retention strategies included implementing financial rewards and benefits, a salary scale, staff development, praise and improving work environment. Nursing directors did not address all perceived challenges in their strategies. To better manage the nursing workforce, nursing directors should regularly measure and monitor nurse turnover rates and also their causes and predictors. Nursing directors should develop, implement and evaluate retention strategies. More information is needed on the management and leadership capacities of nursing directors in addition to their span of control. Nursing directors are facing challenges in retaining their nurses. If these problems are not addressed, Lebanon will continue to lose competent and skilled nurses.

Evaluation of automated sample preparation, retention time locked gas chromatography-mass spectrometry and data analysis methods for the metabolomic study of Arabidopsis species.

PubMed

Gu, Qun; David, Frank; Lynen, Frédéric; Rumpel, Klaus; Dugardeyn, Jasper; Van Der Straeten, Dominique; Xu, Guowang; Sandra, Pat

2011-05-27

In this paper, automated sample preparation, retention time locked gas chromatography-mass spectrometry (GC-MS) and data analysis methods for the metabolomics study were evaluated. A miniaturized and automated derivatisation method using sequential oximation and silylation was applied to a polar extract of 4 types (2 types×2 ages) of Arabidopsis thaliana, a popular model organism often used in plant sciences and genetics. Automation of the derivatisation process offers excellent repeatability, and the time between sample preparation and analysis was short and constant, reducing artifact formation. Retention time locked (RTL) gas chromatography-mass spectrometry was used, resulting in reproducible retention times and GC-MS profiles. Two approaches were used for data analysis. XCMS followed by principal component analysis (approach 1) and AMDIS deconvolution combined with a commercially available program (Mass Profiler Professional) followed by principal component analysis (approach 2) were compared. Several features that were up- or down-regulated in the different types were detected. Copyright © 2011 Elsevier B.V. All rights reserved.

Nuclear reactor melt-retention structure to mitigate direct containment heating

DOEpatents

Tutu, Narinder K.; Ginsberg, Theodore; Klages, John R.

1991-01-01

A light water nuclear reactor melt-retention structure to mitigate the extent of direct containment heating of the reactor containment building. The structure includes a retention chamber for retaining molten core material away from the upper regions of the reactor containment building when a severe accident causes the bottom of the pressure vessel of the reactor to fail and discharge such molten material under high pressure through the reactor cavity into the retention chamber. In combination with the melt-retention chamber there is provided a passageway that includes molten core droplet deflector vanes and has gas vent means in its upper surface, which means are operable to deflect molten core droplets into the retention chamber while allowing high pressure steam and gases to be vented into the upper regions of the containment building. A plurality of platforms are mounted within the passageway and the melt-retention structure to direct the flow of molten core material and help retain it within the melt-retention chamber. In addition, ribs are mounted at spaced positions on the floor of the melt-retention chamber, and grid means are positioned at the entrance side of the retention chamber. The grid means develop gas back pressure that helps separate the molten core droplets from discharged high pressure steam and gases, thereby forcing the steam and gases to vent into the upper regions of the reactor containment building.

Prediction of gradient retention data for hydrophilic interaction liquid chromatographic separation of native and fluorescently labeled oligosaccharides.

PubMed

Vaňková, Nikola; Česla, Petr

2017-02-17

In this work, we have investigated the predictive properties of mixed-mode retention model and oligomeric mixed-mode model, taking into account the contribution of monomeric units to the retention, in hydrophilic interaction liquid chromatography. The gradient retention times of native maltooligosaccharides and their fluorescent derivatives were predicted in the oligomeric series with number of monomeric glucose units in the range from two to seven. The maltooligosaccharides were separated on a packed column with carbamoyl-bonded silica stationary phase and 15 gradient profiles with different initial and final mobile phase composition were used with the gradient times 5; 7.5 and 10min. The predicted gradient retention times were compared for calculations based on isocratic retention data and gradient retention data, which provided better accuracy of the results. By comparing two different mobile phase additives, the more accurate retention times were predicted in mobile phases containing ammonium acetate. The acidic derivatives, prepared by reaction of an oligosaccharide with 2-aminobenzoic acid or 8-aminonaphthalene-1,3,6-trisulfonic acid, provided more accurate predictions of the retention data in comparison to native oligosaccharides or their neutral derivatives. The oligomeric mixed-mode model allowed prediction of gradient retention times using only one gradient profile, which significantly speeded-up the method development. Copyright © 2017 Elsevier B.V. All rights reserved.

Low Elevation Old Channel Features of the Willamette River Floodplain Support High Subsurface Denitrification Rates

EPA Science Inventory

Background/Question/Methods: Large river floodplains are poor nitrate pollution buffers when polluted groundwater moves beneath biogeochemically retentive zones prior to entering the main channel. However, in floodplain regions with extensive backwaters and organic carbon acc...

Predicting Retention Times of Naturally Occurring Phenolic Compounds in Reversed-Phase Liquid Chromatography: A Quantitative Structure-Retention Relationship (QSRR) Approach

PubMed Central

Akbar, Jamshed; Iqbal, Shahid; Batool, Fozia; Karim, Abdul; Chan, Kim Wei

2012-01-01

Quantitative structure-retention relationships (QSRRs) have successfully been developed for naturally occurring phenolic compounds in a reversed-phase liquid chromatographic (RPLC) system. A total of 1519 descriptors were calculated from the optimized structures of the molecules using MOPAC2009 and DRAGON softwares. The data set of 39 molecules was divided into training and external validation sets. For feature selection and mapping we used step-wise multiple linear regression (SMLR), unsupervised forward selection followed by step-wise multiple linear regression (UFS-SMLR) and artificial neural networks (ANN). Stable and robust models with significant predictive abilities in terms of validation statistics were obtained with negation of any chance correlation. ANN models were found better than remaining two approaches. HNar, IDM, Mp, GATS2v, DISP and 3D-MoRSE (signals 22, 28 and 32) descriptors based on van der Waals volume, electronegativity, mass and polarizability, at atomic level, were found to have significant effects on the retention times. The possible implications of these descriptors in RPLC have been discussed. All the models are proven to be quite able to predict the retention times of phenolic compounds and have shown remarkable validation, robustness, stability and predictive performance. PMID:23203132

Extensive Management Promotes Plant and Microbial Nitrogen Retention in Temperate Grassland

PubMed Central

de Vries, Franciska T.; Bloem, Jaap; Quirk, Helen; Stevens, Carly J.; Bol, Roland; Bardgett, Richard D.

2012-01-01

Leaching losses of nitrogen (N) from soil and atmospheric N deposition have led to widespread changes in plant community and microbial community composition, but our knowledge of the factors that determine ecosystem N retention is limited. A common feature of extensively managed, species-rich grasslands is that they have fungal-dominated microbial communities, which might reduce soil N losses and increase ecosystem N retention, which is pivotal for pollution mitigation and sustainable food production. However, the mechanisms that underpin improved N retention in extensively managed, species-rich grasslands are unclear. We combined a landscape-scale field study and glasshouse experiment to test how grassland management affects plant and soil N retention. Specifically, we hypothesised that extensively managed, species-rich grasslands of high conservation value would have lower N loss and greater N retention than intensively managed, species-poor grasslands, and that this would be due to a greater immobilisation of N by a more fungal-dominated microbial community. In the field study, we found that extensively managed, species-rich grasslands had lower N leaching losses. Soil inorganic N availability decreased with increasing abundance of fungi relative to bacteria, although the best predictor of soil N leaching was the C/N ratio of aboveground plant biomass. In the associated glasshouse experiment we found that retention of added 15N was greater in extensively than in intensively managed grasslands, which was attributed to a combination of greater root uptake and microbial immobilisation of 15N in the former, and that microbial immobilisation increased with increasing biomass and abundance of fungi. These findings show that grassland management affects mechanisms of N retention in soil through changes in root and microbial uptake of N. Moreover, they support the notion that microbial communities might be the key to improved N retention through tightening linkages between plants and microbes and reducing N availability. PMID:23227252

Short-Term Effects of Grade Retention on the Growth Rate of Woodcock-Johnson III Broad Math and Reading Scores

PubMed Central

Wu, Wei; West, Stephen G.; Hughes, Jan N.

2008-01-01

We investigated the effects of grade retention in first grade on the growth of the Woodcock-Johnson broad mathematics and reading scores over three years using linear growth curve modeling on an academically at-risk sample. A large sample (n = 784) of first grade children who were at risk for retention were initially identified based on low literacy scores. Scores representing propensity for retention were constructed based on 72 variables collected in comprehensive baseline testing in first grade. We closely matched 97 pairs of retained and promoted children based on their propensity scores using optimal matching procedures. This procedure adjusted for baseline differences between the retained and promoted children. We found that grade retention decreased the growth rate of mathematical skills but had no significant effect on reading skills. In addition, several potential moderators of the effect of retention on growth of mathematical and reading skills were identified including limited English language proficiency and children's conduct problems. PMID:19083352

Short-term effects of grade retention on the growth rate of Woodcock-Johnson III broad math and reading scores.

PubMed

Wu, Wei; West, Stephen G; Hughes, Jan N

2008-02-01

We investigated the effects of grade retention in first grade on the growth of the Woodcock-Johnson broad mathematics and reading scores over three years using linear growth curve modeling on an academically at-risk sample. A large sample (n=784) of first grade children who were at risk for retention was initially identified based on low literacy scores. Scores representing propensity for retention were constructed based on 72 variables collected in comprehensive baseline testing in first grade. We closely matched 97 pairs of retained and promoted children based on their propensity scores using optimal matching procedures. This procedure adjusted for baseline differences between the retained and promoted children. We found that grade retention decreased the growth rate of mathematical skills but had no significant effect on reading skills. In addition, several potential moderators of the effect of retention on growth of mathematical and reading skills were identified including limited English language proficiency and children's conduct problems.

The Space Shuttle orbiter payload retention systems

NASA Technical Reports Server (NTRS)

Hardee, J. H.

1982-01-01

Payloads are secured in the orbiter payload bay by the payload retention system or are equipped with their own unique retention systems. The orbiter payload retention mechanisms provide structural attachments for each payload by using four or five attachment points to secure the payload within the orbiter payload bay during all phases of the orbiter mission. The payload retention system (PRS) is an electromechanical system that provides standarized payload carrier attachment fittings to accommodate up to five payloads for each orbiter flight. The mechanisms are able to function under either l-g or zero-g conditions. Payload berthing or deberthing on orbit is accomplished by utilizing the remote manipulator system (RMS). The retention mechanisms provide the capability for either vertical or horizontal payload installation or removal. The payload support points are selected to minimize point torsional, bending, and radial loads imparted to the payloads. In addition to the remotely controlled latching system, the passive system used for nondeployable payloads performs the same function as the RMS except it provides fixed attachments to the orbiter.

75 FR 71513 - Senior Community Service Employment Program; Notice of Proposed Rulemaking, Additional Indicator...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-23

... to the current measures of employment retention and customer satisfaction. DOL intends for the new...) Retention in unsubsidized employment for 1 year; (2) satisfaction of the participants, employers, and their... unsubsidized employment for 1 year; and (2) the satisfaction of participants, employers and their host agencies...

Catholic School Identity: Perceptions That Influence Teacher Retention

ERIC Educational Resources Information Center

Jakuback, Karen Germany

2017-01-01

The purpose of this qualitative study was to explore teachers' perceptions of various factors, especially Catholic school identity factors, which are important to them and may influence their job satisfaction and retention in Catholic parochial schools after year five of their teaching career. An additional purpose of this study was to inform…

Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges

ERIC Educational Resources Information Center

O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

2009-01-01

Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase…

The Retention of Hispanic/Latino Teachers in Southeastern Rural Elementary Schools

ERIC Educational Resources Information Center

Rodriguez, Oscar

2017-01-01

This qualitative study reviewed reasons so few Hispanic/Latino teachers remain employed with rural county public elementary schools. The study evaluated issues that present high retention and attrition concerns for Hispanic/Latino teachers in rural schools. In addition, the dissertation offered suggestions on ways to increase the representation of…

Regulation of expression of two LY-6 family genes by intron retention and transcription induced chimerism

PubMed Central

Calvanese, Vincenzo; Mallya, Meera; Campbell, R Duncan; Aguado, Begoña

2008-01-01

Background Regulation of the expression of particular genes can rely on mechanisms that are different from classical transcriptional and translational control. The LY6G5B and LY6G6D genes encode LY-6 domain proteins, whose expression seems to be regulated in an original fashion, consisting of an intron retention event which generates, through an early premature stop codon, a non-coding transcript, preventing expression in most cell lines and tissues. Results The MHC LY-6 non-coding transcripts have shown to be stable and very abundant in the cell, and not subject to Nonsense Mediated Decay (NMD). This retention event appears not to be solely dependent on intron features, because in the case of LY6G5B, when the intron is inserted in the artificial context of a luciferase expression plasmid, it is fully spliced but strongly stabilises the resulting luciferase transcript. In addition, by quantitative PCR we found that the retained and spliced forms are differentially expressed in tissues indicating an active regulation of the non-coding transcript. EST database analysis revealed that these genes have an alternative expression pathway with the formation of Transcription Induced Chimeras (TIC). This data was confirmed by RT-PCR, revealing the presence of different transcripts that would encode the chimeric proteins CSNKβ-LY6G5B and G6F-LY6G6D, in which the LY-6 domain would join to a kinase domain and an Ig-like domain, respectively. Conclusion In conclusion, the LY6G5B and LY6G6D intron-retained transcripts are not subjected to NMD and are more abundant than the properly spliced forms. In addition, these genes form chimeric transcripts with their neighbouring same orientation 5' genes. Of interest is the fact that the 5' genes (CSNKβ or G6F) undergo differential splicing only in the context of the chimera (CSNKβ-LY6G5B or G6F-LY6G6C) and not on their own. PMID:18817541

Causes and treatment of oedema in patients with heart failure.

PubMed

Clark, Andrew L; Cleland, John G F

2013-03-01

Oedema is one of the fundamental features of heart failure, but the pathophysiology of oedema varies. Patients present along a spectrum ranging from acute pulmonary oedema to gross fluid retention and peripheral oedema (anasarca). In patients with pure pulmonary oedema, the problem is one of acute haemodynamic derangement; the patient does not have excess fluid, but pulmonary venous pressure rises such that the rate of fluid transudation into the interstitium of the lung exceeds the capacity of the pulmonary lymphatics to drain away the fluid. Conversely, in patients with peripheral oedema, the problem is one of fluid retention. Understanding the causes of oedema will enable straightforward, correct management of the condition. For patients with acute pulmonary oedema, vasodilatation is important to reduce cardiac filling pressures. For patients with fluid retention, removing the fluid, using either diuretics or mechanical means, is the most important consideration.

Thesis Abstract Levels and forms of vitamin D in broilers diets.

PubMed

Mesquita, F R; Silva, M I A; Bertechini, A G

2016-05-09

This study aimed to evaluate the concentration effects of two vitamin D isoforms, cholecalciferol (D3) and 25-hydroxycholecalciferol (25-OHD3) in broilers diets on performance, bone and physiological features of these birds. Of a total of 1920 one-day-old male chicks Cobb-500 were used from commercial hatchery, reared under bed creation systems. The animals were distributed in six treatments and eight replicates with 40 birds per treatment in a completely randomized design. The following vitamin D supplementation levels were applied: 70 and 87.5 μg/kg feed in initial phase; 56 and 70 μg/kg feed during the growth phase, and 35 and 47.35 μg/kg of feed in final phase of creation, obtained from two forms (D3 and 25-OHD3). The treatments consisted of supplementation of two levels from each isolated source and their associations (60% D3 + 40% 25-OHD3) according to the study phases. In the metabolism assay, 480 birds (14 and 35 days of age) were separated to be used for evaluation of calcium (Ca) and phosphorus (P) retention and excretion during the periods of 19 to 21 days and 40 to 42 days of age. The diets were based on corn and soybean meal, with supplementation of phytase (500 FTU/kg). The performance, bone characteristics, plasma levels, bone radiographic density, carcass yield, and P and Ca retention were evaluated. In the initial creation phase, we observed an increased P excretion by broilers fed diets supplemented with vitamin D3 (P < 0.05). In addition, the association between the two vitamin D isoforms resulted in higher retention of Ca and P than the birds fed diets supplemented only with vitamin D3 (P < 0.05), and higher P retention when compared to birds fed diets supplemented with 25-OHD3 (P < 0.05). Dietary supplemental 25-OHD3 at 87.5 μg/kg resulted in higher plasma levels of Ca in relation to the same supplemented source with 70 μg/kg at 21 days of age (P < 0.05). In the final phase, the birds fed diets supplemented with vitamin D3 presented the lowest values of consumption and retention of Ca and P (P < 0.05). The association between the forms (D3 and 25-OHD3) reduced the excretion values of Ca and P (p < 0.05). The birds receiving a source of 25-OHD3 and the association had better feed conversion ratio and higher bone ash content (P < 0.05). At all stages studied D3 + 25-OHD3 combined supplementation increased tibial density of broilers in relation to supplementation of only vitamin D3 (P < 0.05). Results of this study indicate that the addition of 25-OHD3 in the feed supplemented with vitamin D3 improve the feed conversion, increase the Ca plasma levels, and also increases bone density, providing higher retention coefficients of Ca and P and lower P excretion, regardless of the development phase of these birds.

Diagnostic evaluation of oxidoreductive capability of sperm mitochondria.

PubMed

Piasecka, M; Gaczarzewicz, D; Kurzawa, R; Laszczyńska, M; Kram, A

2004-01-01

In the present paper, morphological and functional features of human sperm midpiece, contributing to the assessment of sperm fertility potential, have been described. The NADH-dependent NBT screening assay was used to identify and visualise: 1/ morphological defects of sperm midpiece, 2/ immature sperm forms with extensive cytoplasmic retention, reflecting developmental failure in spermatogenic remodelling process, 3/ cytoplasmic sperm conglomerates, related to apoptotic bodies and 4/ sperm NADH-dependent oxidoreductase system at the mitochondrial level, related to the reaction intensity. The used assay is an adequate marker of sperm mitochondrial activity and sperm maturity. It can also help discover sperm defects that result in asthenozoospermia and can be used as an additional indicator in the evaluation of the sperm midpiece, as well as in routine morphological examination of spermatozoa, having a considerable predictive value for in vivo and in vitro fertilization.

Surface modification and deuterium retention in reduced-activation steels under low-energy deuterium plasma exposure. Part I: undamaged steels

NASA Astrophysics Data System (ADS)

Ogorodnikova, O. V.; Zhou, Z.; Sugiyama, K.; Balden, M.; Gasparyan, Yu.; Efimov, V.

2017-03-01

In this paper, reduced-activation ferritic/martensitic (RAFM) steels including Eurofer (9Cr) and oxide dispersion strengthening (ODS) steels by the addition of Y2O3 particles with different amounts of Cr, namely, (9-16)Cr were exposed to low energy deuterium (D) plasma (~20-200 eV per D) up to a fluence of 2.9  ×  1025 D m-2 in the temperature range from 290 K to 700 K. The depth profile of D in steels was measured up to 8 µm depth by nuclear reaction analysis (NRA) and the total retained amount of D in those materials was determined by thermal desorption spectroscopy (TDS). It was found that the D retention in ODS steels is higher compared to Eurofer due to the much higher density of fine dispersoids and finer grain size. This work shows that in addition to the sintering temperature and time, the type, size and concentration of the doping particles have an enormous effect on the increase in the D retention. The D retention in undamaged ODS steels strongly depends on the Cr content: ODS with 12Cr has a minimum and the D retention in the case of ODS with (14-16)Cr is higher compared to (9-12)Cr. The replacing of Ti by Al in ODS-14Cr steels reduces the D retention. The formation of nano-structure surface roughness enriched in W or Ta due to combination of preferential sputtering of light elements and radiation-induced segregation was observed at incident D ion energy of 200 eV for both Eurofer and ODS steels. Both the surface roughness and the eroded layer enhance with increasing the temperature. The surface modifications result in a reduction of the D retention near the surface due to increasing the desorption flux and can reduce the overall D retention.

A simple approximation for larval retention around reefs

NASA Astrophysics Data System (ADS)

Cetina-Heredia, Paulina; Connolly, Sean R.

2011-09-01

Estimating larval retention at individual reefs by local scale three-dimensional flows is a significant problem for understanding, and predicting, larval dispersal. Determining larval dispersal commonly involves the use of computationally demanding and expensively calibrated/validated hydrodynamic models that resolve reef wake eddies. This study models variation in larval retention times for a range of reef shapes and circulation regimes, using a reef-scale three-dimensional hydrodynamic model. It also explores how well larval retention time can be estimated based on the "Island Wake Parameter", a measure of the degree of flow turbulence in the wake of reefs that is a simple function of flow speed, reef dimension, and vertical diffusion. The mean residence times found in the present study (0.48-5.64 days) indicate substantial potential for self-recruitment of species whose larvae are passive, or weak swimmers, for the first several days after release. Results also reveal strong and significant relationships between the Island Wake Parameter and mean residence time, explaining 81-92% of the variability in retention among reefs across a range of unidirectional flow speeds and tidal regimes. These findings suggest that good estimates of larval retention may be obtained from relatively coarse-scale characteristics of the flow, and basic features of reef geomorphology. Such approximations may be a valuable tool for modeling connectivity and meta-population dynamics over large spatial scales, where explicitly characterizing fine-scale flows around reef requires a prohibitive amount of computation and extensive model calibration.

JT8D engine performance retention

NASA Technical Reports Server (NTRS)

James, A. D.; Weisel, D. R.

1981-01-01

The attractive performance retention characteristics of the JT8D engine are described. Because of its moderate bypass ratio and turbine temperature, and stiff structural design, the performance retention versus flight cycles of the JT8D engine sets a standard that is difficult for other engines to equal. In addition, the significant benefits of refurbishment of the JT8D engine are presented. Cold section refurbishment offers thrust specific fuel consumption improvements of up to 2 percent and payback in less than a year, making a very attractive investment option for the airlines.

Improving subject recruitment, retention, and participation in research through Peplau's theory of interpersonal relations.

PubMed

Penckofer, Sue; Byrn, Mary; Mumby, Patricia; Ferrans, Carol Estwing

2011-04-01

Recruitment and retention of persons participating in research is one of the most significant challenges faced by investigators. Although incentives are often used to improve recruitment and retention, evidence suggests that the relationship of the patient to study personnel may be the single, most important factor in subject accrual and continued participation. Peplau's theory of interpersonal relations provides a framework to study the nurse-patient relationship during the research process. In this paper the authors provide a brief summary of research strategies that have been used for the recruitment and retention of subjects and an overview of Peplau's theory of interpersonal relations including its use in research studies. In addition, a discussion of how this theory was used for the successful recruitment and retention of women with type 2 diabetes who participated in a clinical trial using a nurse-delivered psychoeducational intervention for depression is addressed.

Retention of nucleic acids in ion-pair reversed-phase high-performance liquid chromatography depends not only on base composition but also on base sequence.

PubMed

Qiao, Jun-Qin; Liang, Chao; Wei, Lan-Chun; Cao, Zhao-Ming; Lian, Hong-Zhen

2016-12-01

The study on nucleic acid retention in ion-pair reversed-phase high-performance liquid chromatography mainly focuses on size-dependence, however, other factors influencing retention behaviors have not been comprehensively clarified up to date. In this present work, the retention behaviors of oligonucleotides and double-stranded DNAs were investigated on silica-based C 18 stationary phase by ion-pair reversed-phase high-performance liquid chromatography. It is found that the retention of oligonucleotides was influenced by base composition and base sequence as well as size, and oligonucleotides prone to self-dimerization have weaker retention than those not prone to self-dimerization but with the same base composition. However, homo-oligonucleotides are suitable for the size-dependent separation as a special case of oligonucleotides. For double-stranded DNAs, the retention is also influenced by base composition and base sequence, as well as size. This may be attributed to the interaction of exposed bases in major or minor grooves with the hydrophobic alky chains of stationary phase. In addition, no specific influence of guanine and cytosine content was confirmed on retention of double-stranded DNAs. Notably, the space effect resulted from the stereostructure of nucleic acids also influences the retention behavior in ion-pair reversed-phase high-performance liquid chromatography. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular Mechanisms Controlling GLUT4 Intracellular Retention

PubMed Central

Blot, Vincent

2008-01-01

In basal adipocytes, glucose transporter 4 (GLUT4) is sequestered intracellularly by an insulin-reversible retention mechanism. Here, we analyze the roles of three GLUT4 trafficking motifs (FQQI, TELEY, and LL), providing molecular links between insulin signaling, cellular trafficking machinery, and the motifs in the specialized trafficking of GLUT4. Our results support a GLUT4 retention model that involves two linked intracellular cycles: one between endosomes and a retention compartment, and the other between endosomes and specialized GLUT4 transport vesicles. Targeting of GLUT4 to the former is dependent on the FQQI motif and its targeting to the latter is dependent on the TELEY motif. These two motifs act independently in retention, with the TELEY-dependent step being under the control of signaling downstream of the AS160 rab GTPase activating protein. Segregation of GLUT4 from endosomes, although positively correlated with the degree of basal retention, does not completely account for GLUT4 retention or insulin-responsiveness. Mutation of the LL motif slows return to basal intracellular retention after insulin withdrawal. Knockdown of clathrin adaptin protein complex-1 (AP-1) causes a delay in the return to intracellular retention after insulin withdrawal. The effects of mutating the LL motif and knockdown of AP-1 were not additive, establishing that AP-1 regulation of GLUT4 trafficking requires the LL motif. PMID:18550797

Selectivity differences of water-soluble vitamins separated on hydrophilic interaction stationary phases.

PubMed

Yang, Yuanzhong; Boysen, Reinhard I; Hearn, Milton T W

2013-06-01

In this study, the retention behavior and selectivity differences of water-soluble vitamins were evaluated with three types of polar stationary phases (i.e. an underivatized silica phase, an amide phase, and an amino phase) operated in the hydrophilic interaction chromatographic mode with ESI mass spectrometric detection. The effects of mobile phase composition, including buffer pH and concentration, on the retention and selectivity of the vitamins were investigated. In all stationary phases, the neutral or weakly charged vitamins exhibited very weak retention under each of the pH conditions, while the acidic and more basic vitamins showed diverse retention behaviors. With the underivatized silica phase, increasing the salt concentration of the mobile phase resulted in enhanced retention of the acidic vitamins, but decreased retention of the basic vitamins. These observations thus signify the involvement of secondary mechanisms, such as electrostatic interaction in the retention of these analytes. Under optimized conditions, a baseline separation of all vitamins was achieved with excellent peak efficiency. In addition, the effects of water content in the sample on retention and peak efficiency were examined, with sample stacking effects observed when the injected sample contained a high amount of water. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control of ice chromatographic retention mechanism by changing temperature and dopant concentration.

PubMed

Tasaki, Yuiko; Okada, Tetsuo

2011-12-15

A liquid phase coexists with solid water ice in a typical binary system, such as NaCl-water, in the temperature range between the freezing point and the eutectic point (t(eu)) of the system. In ice chromatography with salt-doped ice as the stationary phase, both solid and liquid phase can contribute to solute retention in different fashions; that is, the solid ice surface acts as an adsorbent, while a solute can be partitioned into the liquid phase. Thus, both adsorption and partition mechanisms can be utilized for ice chromatographic separation. An important feature in this approach is that the liquid phase volume can be varied by changing the temperature and the concentration of a salt incorporated into the ice stationary phase. Thus, we can control the relative contribution from the partition mechanism in the entire retention because the liquid phase volume can be estimated from the freezing depression curve. Separation selectivity can thereby be modified. The applicability of this concept has been confirmed for the solutes of different adsorption and partition abilities. The predicted retention based on thermodynamics basically agrees well with the corresponding experimental retention. However, one important inconsistency has been found. The calculation predicts a step-like discontinuity of the solute retention at t(eu) because the phase diagram suggests that the liquid phase abruptly appears at t(eu) when the temperature increases. In contrast, the corresponding experimental plots are continuous over the wider range including the subeutectic temperatures. This discrepancy is explained by the existence of the liquid phase below t(eu). A difference between predicted and measured retention factors allows the estimation of the volume of the subeutectic liquid phase.

Evaluating electrolyte additives for lithium-ion cells: A new Figure of Merit approach

NASA Astrophysics Data System (ADS)

Tornheim, Adam; Peebles, Cameron; Gilbert, James A.; Sahore, Ritu; Garcia, Juan C.; Bareño, Javier; Iddir, Hakim; Liao, Chen; Abraham, Daniel P.

2017-10-01

Electrolyte additives are known to improve the performance of lithium-ion cells. In this work we examine the performance of Li1.03Ni0.5Mn0.3Co0.3O2-graphite (NMC532/Gr) cells containing combinations of lithium bis(oxalate)borate (LiBOB), vinylene carbonate (VC), trivinylcyclotriboroxane (tVCBO), prop-1-ene-1,3-sultone (PES), phenyl boronic acid ethylene glycol ester (PBE), tris(trimethylsilyl) phosphite (TMSPi), triethyl phosphite (TEPi), and lithium difluoro(oxalate)borate (LiDFOB) added to our baseline (1.2 M LiPF6 in EC:EMC, 3:7 w/w) electrolyte. In order to rank performance of the various electrolytes, we developed two separate figures of merit (FOM), which are based on the energy retention and power retention of the cells. Using these two metrics in conjunction, we show that only one of the fifteen electrolyte formulations tested significantly outperforms the baseline electrolyte: this electrolyte contains the 0.25 wt% tVCBO + 1 wt% TMSPi additive mix. Little correlation was observed between the FOMs for energy retention and power retention, which indicates that the mechanisms that govern these performance parameters are likely independent of each other. Our FOM approach has general applicability and can be used to develop electrolyte and electrode formulations that prolong the life of lithium-ion batteries.

Evaluating electrolyte additives for lithium-ion cells: A new Figure of Merit approach

DOE PAGES

Tornheim, Adam; Peebles, Cameron; Gilbert, James A.; ...

2017-09-01

Electrolyte additives are known to improve the performance of lithium-ion cells. In this work we examine the performance of Li 1.03Ni 0.5Mn 0.3Co 0.3O 2-graphite (NMC532/Gr) cells containing combinations of lithium bis(oxalate)borate (LiBOB), vinylene carbonate (VC), trivinylcyclotriboroxane (tVCBO), prop-1-ene-1,3-sultone (PES), phenyl boronic acid ethylene glycol ester (PBE), tris(trimethylsilyl) phosphite (TMSPi), triethylphosphite (TEPi), and lithium difluoro(oxalate)borate (LiDFOB) added to our baseline (1.2M LiPF 6 in EC:EMC, 3:7 w/w) electrolyte. In order to rank performance of the various electrolytes, we developed two separate figures of merit (FOM), which are based on the energy retention and power retention of the cells. Using thesemore » two metrics in conjunction, we show that only one of the fifteen electrolyte formulations tested significantly outperforms the baseline electrolyte: this electrolyte contains the 0.25 wt% tVCBO + 1 wt% TMSPi additive mix. Little correlation was observed between the FOMs for energy retention and power retention, which indicates that the mechanisms that govern these performance parameters are likely independent of each other. In conclusion, our FOM approach has general applicability and can be used to develop electrolyte and electrode formulations that prolong the life of lithium-ion batteries.« less

Evaluating electrolyte additives for lithium-ion cells: A new Figure of Merit approach

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

Tornheim, Adam; Peebles, Cameron; Gilbert, James A.

Electrolyte additives are known to improve the performance of lithium-ion cells. In this work we examine the performance of Li 1.03Ni 0.5Mn 0.3Co 0.3O 2-graphite (NMC532/Gr) cells containing combinations of lithium bis(oxalate)borate (LiBOB), vinylene carbonate (VC), trivinylcyclotriboroxane (tVCBO), prop-1-ene-1,3-sultone (PES), phenyl boronic acid ethylene glycol ester (PBE), tris(trimethylsilyl) phosphite (TMSPi), triethylphosphite (TEPi), and lithium difluoro(oxalate)borate (LiDFOB) added to our baseline (1.2M LiPF 6 in EC:EMC, 3:7 w/w) electrolyte. In order to rank performance of the various electrolytes, we developed two separate figures of merit (FOM), which are based on the energy retention and power retention of the cells. Using thesemore » two metrics in conjunction, we show that only one of the fifteen electrolyte formulations tested significantly outperforms the baseline electrolyte: this electrolyte contains the 0.25 wt% tVCBO + 1 wt% TMSPi additive mix. Little correlation was observed between the FOMs for energy retention and power retention, which indicates that the mechanisms that govern these performance parameters are likely independent of each other. In conclusion, our FOM approach has general applicability and can be used to develop electrolyte and electrode formulations that prolong the life of lithium-ion batteries.« less

When Does Testing Enhance Retention? A Distribution-Based Interpretation of Retrieval as a Memory Modifier

ERIC Educational Resources Information Center

Halamish, Vered; Bjork, Robert A.

2011-01-01

Tests, as learning events, can enhance subsequent recall more than do additional study opportunities, even without feedback. Such advantages of testing tend to appear, however, only at long retention intervals and/or when criterion tests stress recall, rather than recognition, processes. We propose that the interaction of the benefits of testing…

The Marine Corps Enlisted Assignment Process: The Customer’s Perspective

DTIC Science & Technology

2003-03-01

continue service in the Marine Corps or to leave. Additionally, this process affects career development, quality of life , and ultimately their lives...retention goals. If not, the Marine Corps may increase quality of life by introducing new assignment processes or systems. These changes could also increase enlisted Marines’ retention rate, and ultimately personnel readiness.

Linking Learning Style Theory with Retention Research: The TRAILS Project. AIR 1986 Annual Forum Paper.

ERIC Educational Resources Information Center

Kalsbeek, David H.

The Myers-Briggs Type Indicator (MBTI), a measure of personality type and learning style, was used at Saint Louis University in the TRAILS (Tracking Retention and Academic Integration by Learning Style) Project. In addition to considering links between learning styles and student academic achievement and aptitude, MBTI was used to identify…

START! The Successful Transitions and Retention Track Program: A Comprehensive Approach to Supporting GED Holders Entering College

ERIC Educational Resources Information Center

Nix, J. Vincent; Michalak, Megan B.

2012-01-01

Students entering college face many obstacles to success. Students who received a General Education Development (GED) face additional barriers that must be addressed in order for success in higher education. The Successful Transitions and Retention Track Program employs a holistic approach to addressing the needs of GED holders entering college.

A combination of a dairy product fermented by lactobacilli and galactooligosaccharides shows additive effects on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor.

PubMed

Takasugi, Satoshi; Ashida, Kinya; Maruyama, Suyaka; Matsukiyo, Yukari; Kaneko, Tetsuo; Yamaji, Taketo

2013-06-01

This study aimed to investigate the effects of a combination of a dairy product fermented by lactobacilli (DFL) and galactooligosaccharides (GOS) on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor (PPI). Three-week-old male rats were assigned to receive one of six diets: a control diet, control diets containing 1.6 or 5.0 % GOS, a DFL diet and DFL diets containing 1.6 or 5.0 % GOS for 9 days. From day 5 of the feeding period, half of the rats fed with control diets were subcutaneously administered with saline, whereas the remaining rats were administered with PPI for 5 days. Calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe) and zinc (Zn) balances were determined from days 6 to 9. PPI administration significantly decreased the apparent absorption of Ca and Fe and increased urinary P excretion, resulting in decreased Ca, Fe and P retention. GOS dose-dependently increased the apparent absorption of Ca, Mg and Fe and urinary Mg excretion and decreased urinary P excretion. DFL significantly increased the apparent absorption of Ca and Mg and urinary Mg excretion. The combination of DFL and GOS additively affected these parameters, resulting in increased Ca, P and Fe retention, and it further increased the apparent absorption and retention of Zn at 5.0 % GOS. In conclusion, the combination of DFL and GOS improves Ca, P and Fe retention in an additive manner and increases the Zn retention in growing rats with hypochlorhydria induced by PPI.

The influence of salt chaotropicity, column hydrophobicity and analytes' molecular properties on the retention of pramipexole and its impurities.

PubMed

Vemić, Ana; Kalinić, Marko; Erić, Slavica; Malenović, Anđelija; Medenica, Mirjana

2015-03-20

The aim of this study was to examine the interaction of the chaotropic salts of different position in Hofmeister series (CF3COONa, NaClO4, NaPF6) added to the mobile phase with the stationary phases of different hydrophobicity (C8 and C18 XTerra(®) columns), as well as their common influence on the retention behavior of pramipexole and its structurally related impurities. The extended thermodynamic approach enabled the understanding of the underlying separation mechanism. Comparing six different column-salt systems it was observed that general system hydrophobicity presented by salt chaotropicity and column hydrophobicity favors stationary phase ion-pairing over the ion-pair formation in the eluent. Further, an attempt was made to describe the influence of analytes' nature on their retention behavior in such chromatographic systems. An analysis is performed in order to select and elucidate the molecular descriptors (electrostatical, quantum-chemical, geometrical, topological, and constitutional) that best explain the experimental evidence and findings obtained by the thermodynamic approach. The results of this analysis suggest that analytes' charge distribution and its complementarity to the structure of the electric double layer formed on the surface of the stationary phase upon the addition of chaotropic additives can be useful for understanding the differences in retention of structurally related analytes. These findings provide a novel understanding of the interactions between all the components of the chromatographic system containing chaotropic additive and a good basis for further investigations suggesting the development of generally applicable predictors in structure-retention relationship studies in related chromatographic systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of audio-visual aids on foreign language test anxiety, reading and listening comprehension, and retention in EFL learners.

PubMed

Lee, Shu-Ping; Lee, Shin-Da; Liao, Yuan-Lin; Wang, An-Chi

2015-04-01

This study examined the effects of audio-visual aids on anxiety, comprehension test scores, and retention in reading and listening to short stories in English as a Foreign Language (EFL) classrooms. Reading and listening tests, general and test anxiety, and retention were measured in English-major college students in an experimental group with audio-visual aids (n=83) and a control group without audio-visual aids (n=94) with similar general English proficiency. Lower reading test anxiety, unchanged reading comprehension scores, and better reading short-term and long-term retention after four weeks were evident in the audiovisual group relative to the control group. In addition, lower listening test anxiety, higher listening comprehension scores, and unchanged short-term and long-term retention were found in the audiovisual group relative to the control group after the intervention. Audio-visual aids may help to reduce EFL learners' listening test anxiety and enhance their listening comprehension scores without facilitating retention of such materials. Although audio-visual aids did not increase reading comprehension scores, they helped reduce EFL learners' reading test anxiety and facilitated retention of reading materials.

Effect of ground poppy seed as a fat replacer on meat burgers.

PubMed

Gök, Veli; Akkaya, Levent; Obuz, Ersel; Bulut, Sait

2011-12-01

Poppy seed paste was used in koefte production as an animal fat replacer and efficacy of using poppy seed was investigated. The use of ground poppy seed in formulation of meat burgers had no effect on the moisture content of uncooked meat burgers; however, it did have a significant effect (p<0.05) on the fat content of meat burgers. Ground poppy seed addition significantly affected (p<0.05) cooking yield, moisture retention, and fat retention of meat burgers. Ground poppy seed addition significantly decreased (p<0.05) saturated fatty acid contents as the amount of ground poppy seed increased in meat burgers. A strong significant decrease (p<0.05) on the cholesterol content of meat burgers with ground poppy seed addition was observed. Samples having 20% ground poppy seed had significantly better texture and juiciness score (p<0.05) than any other sample which could be explained by increased moisture retention. Replacing animal fat with ground poppy seed paste is effective and may pave the way for an innovative meat product. Copyright © 2011 Elsevier Ltd. All rights reserved.

Gap-enhanced Raman tags for high-contrast sentinel lymph node imaging.

PubMed

Bao, Zhouzhou; Zhang, Yuqing; Tan, Ziyang; Yin, Xia; Di, Wen; Ye, Jian

2018-05-01

The sentinel lymph node (SLN) biopsy is gaining in popularity as a procedure to investigate the lymphatic metastasis of malignant tumors. The commonly used techniques to identify the SLNs in clinical practice are blue dyes-guided visualization, radioisotope-based detection and near-infrared fluorescence imaging. However, all these methods have not been found to perfectly fit the clinical criteria with issues such as short retention time in SLN, poor spatial resolution, autofluorescence, low photostability and high cost. In this study, we have reported a new type of nanoprobes, named, gap-enhanced Raman tags (GERTs) for the SLN Raman imaging. With the advantageous features including unique "fingerprint" Raman signal, strong Raman enhancement, high photostability, good biocompatibility and extra-long retention time, we have demonstrated that GERTs are greatly favorable for high-contrast and deep SLN Raman imaging, which meanwhile reveals the dynamic migration behavior of the probes entering the SLN. In addition, a quantitative volumetric Raman imaging (qVRI) data-processing method is employed to acquire a high-resolution 3-dimensional (3D) margin of SLN as well as the content variation of GERTs in the SLN. Moreover, SLN detection could be realized via a cost-effective commercial portable Raman scanner. Therefore, GERTs hold the great potential to be translated in clinical application for accurate and intraoperative location of the SLN. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pre-flight safety briefings, mood and information retention.

PubMed

Tehrani, Morteza; Molesworth, Brett R C

2015-11-01

Mood is a moderating factor that is known to affect performance. For airlines, the delivery of the pre-flight safety briefing prior to a commercial flight is not only an opportunity to inform passengers about the safety features on-board the aircraft they are flying, but an opportunity to positively influence their mood, and hence performance in the unlikely event of an emergency. The present research examined whether indeed the pre-flight safety briefing could be used to positively impact passengers' mood. In addition, the present research examined whether the recall of key safety messages contained within the pre-flight safety briefing was influenced by the style of briefing. Eighty-two participants were recruited for the research and divided into three groups; each group exposed to a different pre-flight cabin safety briefing video (standard, humorous, movie theme). Mood was measured prior and post safety briefing. The results revealed that pre-flight safety briefing videos can be used to manipulate passengers' mood. Safety briefings that are humorous or use movie themes to model their briefing were found to positively affect mood. However, there was a trade-off between entertainment and education, the greater the entertainment value, the poorer the retention of key safety messages. The results of the research are discussed from both an applied and theoretical perspective. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

DIN retention-transport through four hydrologically connected zones in a headwater catchment of the Upper Mississippi River

USGS Publications Warehouse

Triska, F.J.; Duff, J.H.; Sheibley, R.W.; Jackman, A.P.; Avanzino, R.J.

2007-01-01

Dissolved inorganic nitrogen (DIN) retention-transport through a headwater catchment was synthesized from studies encompassing four distinct hydrologic zones of the Shingobee River Headwaters near the origin of the Mississippi River. The hydrologic zones included: (1) hillslope ground water (ridge to bankside riparian); (2) alluvial riparian ground water; (3) ground water discharged through subchannel sediments (hyporheic zone); and (4) channel surface water. During subsurface hillslope transport through Zone 1, DIN, primarily nitrate, decreased from ???3 mg-N/l to <0.1 mg-N/l. Ambient seasonal nitrate:chloride ratios in hillslope flow paths indicated both dilution and biotic processing caused nitrate loss. Biologically available organic carbon controlled biotic nitrate retention during hillslope transport. In the alluvial riparian zone (Zone 2) biologically available organic carbon controlled nitrate depletion although processing of both ambient and amended nitrate was faster during the summer than winter. In the hyporheic zone (Zone 3) and stream surface water (Zone 4) DIN retention was primarily controlled by temperature. Perfusion core studies using hyporheic sediment indicated sufficient organic carbon in bed sediments to retain ground water DIN via coupled nitrification-denitrification. Numerical simulations of seasonal hyporheic sediment nitrification-denitrification rates from perfusion cores adequately predicted surface water ammonium but not nitrate when compared to 5 years of monthly field data (1989-93). Mass balance studies in stream surface water indicated proportionally higher summer than winter N retention. Watershed DIN retention was effective during summer under the current land use of intermittently grazed pasture. However, more intensive land use such as row crop agriculture would decrease nitrate retention efficiency and increase loads to surface water. Understanding DIN retention capacity throughout the system, including special channel features such as sloughs, wetlands and floodplains that provide surface water-ground water connectivity, will be required to develop effective nitrate management strategies. ?? 2007 American Water Resources Association.

Special Diabetes Program for Indians: Retention in Cardiovascular Risk Reduction

PubMed Central

Manson, Spero M.; Jiang, Luohua; Zhang, Lijing; Beals, Janette; Acton, Kelly J.; Roubideaux, Yvette

2011-01-01

Purpose: This study examined the associations between participant and site characteristics and retention in a multisite cardiovascular disease risk reduction project. Design and Methods: Data were derived from the Special Diabetes Program for Indians Healthy Heart Demonstration Project, an intervention to reduce cardiovascular risk among American Indians and Alaska Natives with diabetes. In 2006, a total of 1,072 participants from 30 participating sites completed baseline questionnaires measuring demographics and sociobehavioral factors. They also underwent a medical examination at baseline and were reassessed annually after baseline. A Provider Annual Questionnaire was administered to staff members of each grantee site at the end of each year to assess site characteristics. Generalized estimating equation models were used to evaluate the relationships between participant and site characteristics and retention 1 year after baseline. Results: Among enrolled participants, 792 (74%) completed their first annual assessment. Participants who completed the first annual assessment tended to be older and had, at baseline, higher body mass index and higher level of physical activity. Site characteristics associated with retention included average age of staff, proportion of female staff members, and percentage of staff members having completed graduate or professional school. Implications: Understanding successful retention must reach beyond individual characteristics of participants to include features of the settings that house the interventions. PMID:21565816

Hydrophilic interaction chromatography coupled matrix assisted laser desorption/ionization mass spectrometry for molecular analysis of organic compounds in medicines, tea, and coffee.

PubMed

Wang, Ren-Qi; Bao, Kai; Croué, Jean-Philippe; Ng, Siu Choon

2013-11-21

Natural occurring organic compounds from food, natural organic matter, as well as metabolic products have received intense attention in current chemical and biological studies. Examination of unknown compounds in complex sample matrices is hampered by the limited choices for data readout and molecular elucidation. Herein, we report a generic method of hydrophilic interaction chromatography (HILIC) coupled with matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the rapid characterization of ingredients in pharmaceutical compounds, tea, and coffee. The analytes were first fractionated using a cationic HILIC column prior to MALDI-MS analyses. It was found that the retention times of a compound arising from different samples were consistent under the same conditions. Accordingly, molecules can be readily characterized by both the mass and chromatographic retention time. The retention behaviors of acidic and basic compounds on the cationic HILIC column were found to be significantly influenced by the pH of mobile phases, whereas neutral compounds depicted a constant retention time at different pH. The general HILIC-MALDI-MS method is feasible for fast screening of naturally occurring organic compounds. A series of homologs can be determined if they have the same retention behavior. Their structural features can be elucidated by considering their mass differences and hydrophilic properties as determined by HILIC chromatogram.

NIA outreach to minority and health disparity populations can a toolbox for recruitment and retention be far behind?

PubMed

Harden, J Taylor; Silverberg, Nina

2010-01-01

The ability to locate the right research tool at the right time for recruitment and retention of minority and health disparity populations is a challenge. This article provides an introduction to a number of recruitment and retention tools in a National Institute on Aging Health Disparities Toolbox and to this special edition on challenges and opportunities in recruitment and retention of minority populations in Alzheimer disease and dementia research. The Health Disparities Toolbox and Health Disparities Resource Persons Network are described along with other more established resource tools including the Alzheimer Disease Center Education Cores, Alzheimer Disease Education and Referral Center, and Resource Centers for Minority Aging Research. Nine featured articles are introduced. The articles address a range of concerns including what we know and do not know, conceptual and theoretical perspectives framing issues of diversity and inclusion, success as a result of sustained investment of time and community partnerships, the significant issue of mistrust, willingness to participate in research as a dynamic personal attribute, Helpline Service and the amount of resources required for success, assistance in working with Limited English Proficiency elders, and sage advice from social marketing and investigations of health literacy as a barrier to recruitment and retention. Finally, an appeal is made for scientists to share tools for the National Institute on Aging Health Disparity Toolbox and to join the Health Disparities Resource Persons Network.

A parametric study of helium retention in beryllium and its effect on deuterium retention

NASA Astrophysics Data System (ADS)

Alegre, D.; Baldwin, M. J.; Simmonds, M.; Nishijima, D.; Hollmann, E. M.; Brezinsek, S.; Doerner, R. P.

2017-12-01

Beryllium samples have been exposed in the PISCES-B linear plasma device to conditions relevant to the International Thermonuclear Experimental Reactor (ITER) in pure He, D, and D/He mixed plasmas. Except at intermediate sample exposure temperatures (573-673 K) He addition to a D plasma is found to have a beneficial effect as it reduces the D retention in Be (up to ˜55%), although the mechanism is unclear. Retention of He is typically around 1020-1021 He m-2, and is affected primarily by the Be surface temperature during exposition, by the ion fluence at <500 K exposure, but not by the ion impact energy at 573 K. Contamination of the Be surface with high-Z elements from the mask of the sample holder in pure He plasmas is also observed under certain conditions, and leads to unexpectedly large He retention values, as well as changes in the surface morphology. An estimation of the tritium retention in the Be first wall of ITER is provided, being sufficiently low to allow a safe operation of ITER.

Recruitment and retention strategies for hospital laboratory personnel in urban and rural settings.

PubMed

Slagle, Derek R

2013-01-01

Laboratory directors and administrators play vital roles in the recruitment and retention processes of their employees. A total of 71 laboratory directors from hospitals across 51 counties in Tennessee responded to questionnaires regarding recruitment and retention strategies. Respondents reported strategies for recruitment and retention, which were agreed to be effective by management. Overall, these major strategies were consistent regardless of geographic location and limited differences were noted with regard to urban-rural locations. The findings that varied significantly between urban and rural locations included: 1) rural employees needed additional supervision; 2) rural hospitals relied on local residents more so than urban hospitals; 3) rural laboratory administrators noted more limited access to resources; and the 4) lower effectiveness of recruitment agencies and family relocation programs for rural hospitals. This is significant given the disparities often associated with rural areas, and the potential to develop more successful recruitment and retention strategies for those areas. Active managers in clinical laboratory science programs in the hospital setting should note effective strategies for both, recruitment and retention of personnel, and note the potential impact of geography on such processes.

Spotlight on Transition to Teaching Music

ERIC Educational Resources Information Center

MENC: The National Association for Music Education, 2004

2004-01-01

The latest title in the popular Spotlight series, this timely book focuses on issues involving recruitment and retention of music teachers, a crucial issue in these days of budget constraints. Arranged chronologically, it features a collection of articles from state journals focusing on issues such as mentoring, teacher shortages, burnout, and…

Spatial Variation in Microbial Populations Across a Cattle Feedlot Transect from Barn to Retention Basin

USDA-ARS?s Scientific Manuscript database

Run-off from livestock production can pose a risk to environmental quality particularly in karst terrains where geomorphic features like sinkholes provide rapid passage for contaminants to ground water resources. In these environments, it is especially important to understand how variations in terr...

Recruitment Rhetoric in Brochures Advertising the All Volunteer Force.

ERIC Educational Resources Information Center

Shyles, Leonard; Ross, Mark

1984-01-01

Analyzed inducements offered in brochures advertising the volunteer army. Found that (1) the appeals focused on education benefits, military/civilian job training, and economic incentives and (2) few appeals featured the intrinsic satisfactions of military service. Considers the implications in terms of recruitment and retention problems. (PD)

The neurophysiology of urinary retention in young women and its treatment by neuromodulation.

PubMed

Goodwin, R J; Swinn, M J; Fowler, C J

1998-01-01

Urinary retention occurring in young women as an isolated phenomenon was often thought to be psychogenic in origin. However, in 1988, Fowler et al. described a syndrome in young women in which urinary retention was the predominant feature and in which electromyography (EMG) of the striated urethral sphincter revealed a striking abnormality. This abnormality, it was postulated, would result in an inability of the sphincter to relax and retention would therefore result. Until recently there was no effective treatment for this disorder except management by clean intermittent self-catheterisation. However, preliminary results of neuromodulation using a Medtronic sacral nerve stimulator have been particularly promising in this group of patients. The response is often spectacular; a woman who has not passed urine per urethram for many months or years will frequently find that within a few hours of insertion of the percutaneous nerve evaluation (PNE) lead, she can void quite normally with little or no residual urine. The precise mechanism of action is yet to be defined, but measurements of the latency of anal sphincter contraction on S3 stimulation during PNE are so prolonged that they can only be the result of an afferent-mediated reflex.

Retaining the mental health nursing workforce: early indicators of retention and attrition.

PubMed

Robinson, Sarah; Murrells, Trevor; Smith, Elizabeth M

2005-12-01

In the UK, strategies to improve retention of the mental health workforce feature prominently in health policy. This paper reports on a longitudinal national study into the careers of mental health nurses in the UK. The findings reveal little attrition during the first 6 months after qualification. Investigation of career experiences showed that the main sources of job satisfaction were caregiving opportunities and supportive working relationships. The main sources of dissatisfaction were pay in relation to responsibility, paperwork, continuing education opportunities, and career guidance. Participants were asked whether they predicted being in nursing in the future. Gender and ethnicity were related to likelihood to remain in nursing in 5 years time. Age, having children, educational background, ethnic background, and time in first job were associated with likelihood of remaining in nursing at 10 years. Associations between elements of job satisfaction (quality of clinical supervision, ratio of qualified to unqualified staff, support from immediate line manager, and paperwork) and anticipated retention are complex and there are likely to be interaction effects because of the complexity of the issues. Sustaining positive experiences, remedying sources of dissatisfaction, and supporting diplomats from all backgrounds should be central to the development of retention strategies.

Hydrogen trapping under the effect of W-C mixed layers

NASA Astrophysics Data System (ADS)

Liu, N.; Huang, J.; Sato, K.; Xu, Q.; Shi, L. Q.; Wang, Y. X.

2014-03-01

The retention of hydrogen (H) isotope in plasma-facing materials (PFMs) is an important issue for next step fusion device. We used density functional theory (DFT) to study the chemical bonds of H in tungsten-carbon (W-C) mixed layers of tungsten surface, aiming to explore the retention behaviour of H in PFMs. The solubility of C in W was first calculated for revealing the phase components in W-C mixed layers. It was found that C has low solubility in W, which prefers to be segregated on the W surface. Vacancies can enhance the solution of C in W. This makes C appear somewhat carbide feature. Thus, W-C mixed layers should contain multiple phase components. H retention strongly depends on the phase components in the W-C mixed layers. The solution of C will suppress the retention of H in W no matter whether neighbouring vacancies are present, or not. Hydrocarbon precursors, which were observed in desorption experiments, prefer to form by means of H binding to C atoms in C amorphous, or in precipitators in the W-C mixed layers, while not in tungsten carbide phase or in W bulk. Our investigation reasonably explains the experimental results.

Digital Device Architecture and the Safe Use of Flash Devices in Munitions

NASA Technical Reports Server (NTRS)

Katz, Richard B.; Flowers, David; Bergevin, Keith

2017-01-01

Flash technology is being utilized in fuzed munition applications and, based on the development of digital logic devices in the commercial world, usage of flash technology will increase. Digital devices of interest to designers include flash-based microcontrollers and field programmable gate arrays (FPGAs). Almost a decade ago, a study was undertaken to determine if flash-based microcontrollers could be safely used in fuzes and, if so, how should such devices be applied. The results were documented in the Technical Manual for the Use of Logic Devices in Safety Features. This paper will first review the Technical Manual and discuss the rationale behind the suggested architectures for microcontrollers and a brief review of the concern about data retention in flash cells. An architectural feature in the microcontroller under study will be discussed and its use will show how to screen for weak or failed cells during manufacture, storage, or immediately prior to use. As was done for microcontrollers a decade ago, architectures for a flash-based FPGA will be discussed, showing how it can be safely used in fuzes. Additionally, architectures for using non-volatile (including flash-based) storage will be discussed for SRAM-based FPGAs.

[Recurrent urinary tract infection due to enterovesical fistula secondary to colon diverticular disease: a case report].

PubMed

Cavalcanti, Natália Silva; da Silva, Lorena Luryann Cartaxo; da Silva, Leonardo Sales; da Fonseca, Luiz Antonio Cavalcante; Alexandre, Cristianne da Silva

2013-01-01

Enterovesical fistula are pathological connections between the bladder and pelvic intestinal segments. It consists of a rare complication of neoplastic and inflammatory pelvic disorders, in addition to iatrogenic or traumatic injuries, and correlates with both high morbidity and mortality indexes. Male patient, 61 years old, admitted at the hospital clinics featuring abdominal pain and distension, vomiting and fecal retention. Patient's pathological precedents include high blood pressure, diabetes mellitus, vesical dysfunction and recurrent urinary tract infection on the past three years. Magnetic resonance imaging of abdomen and pelvis revealed enterovesical fistula in association with colon diverticular disease of the sigmoid. Management of choice consisted of partial colectomy with bowel lowering and partial cystectomy with surgical double-J stent insertion. Although consisting of a gastrointestinal primary affection, patients with enterovesical fistula usually search for medical help charging urinary tract features. In this particular case, our patient was admitted with gastrointestinal symptoms, reasoned by diagnostic delay, as the patient had already attended at multiple centers with urinary symptoms. Despite being an unusual affection, recurrent urinary tract infection associated with colon diverticular disease must always be considered at differential diagnosis of recurrent urinary tract infection as it concurs with high morbidity and mortality.

A murine model of autosomal dominant neurohypophyseal diabetes insipidus reveals progressive loss of vasopressin-producing neurons

PubMed Central

Russell, Theron A.; Ito, Masafumi; Ito, Mika; Yu, Richard N.; Martinson, Fred A.; Weiss, Jeffrey; Jameson, J. Larry

2003-01-01

Familial neurohypophyseal diabetes insipidus (FNDI) is an autosomal dominant disorder caused by mutations in the arginine vasopressin (AVP) precursor. The pathogenesis of FNDI is proposed to involve mutant protein–induced loss of AVP-producing neurons. We established murine knock-in models of two different naturally occurring human mutations that cause FNDI. A mutation in the AVP signal sequence [A(–1)T] is associated with a relatively mild phenotype or delayed presentation in humans. This mutation caused no apparent phenotype in mice. In contrast, heterozygous mice expressing a mutation that truncates the AVP precursor (C67X) exhibited polyuria and polydipsia by 2 months of age and these features of DI progressively worsened with age. Studies of the paraventricular and supraoptic nuclei revealed induction of the chaperone protein BiP and progressive loss of AVP-producing neurons relative to oxytocin-producing neurons. In addition, Avp gene products were not detected in the neuronal projections, suggesting retention of WT and mutant AVP precursors within the cell bodies. In summary, this murine model of FNDI recapitulates many features of the human disorder and demonstrates that expression of the mutant AVP precursor leads to progressive neuronal cell loss. PMID:14660745

Does Spatial or Visual Information in Maps Facilitate Text Recall?: Reconsidering the Conjoint Retention Hypothesis

ERIC Educational Resources Information Center

Griffin, Marlynn M.; Robinson, Daniel H.; Sarama, Julie

2005-01-01

The conjoint retention hypothesis (CRH) claims that students recall more text information when they study geographic maps in addition to text than when they study text alone, because the maps are encoded spatially (Kulhavy, Lee, & Caterino, 1985). This claim was recently challenged by Griffin and Robinson (2000), who found no advantage for maps…

Third-Grade Retention: A Four Year Follow-Up. Research Brief. Volume 0706

ERIC Educational Resources Information Center

Froman, Terry; Brown, Shelly; Luzon-Canasi, Angela

2008-01-01

This study duplicated the procedures used by Greene and Winters (2006) on data from the Miami-Dade school system with the advantage of an additional two year's worth of information. The results indicated that the effects of the retention policy are far from clear and arguably negative. There is considerable evidence to suggest that the apparent…

75 FR 65368 - Additional Waivers Granted to and Alternative Requirements for the State of Illinois' CDBG...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-22

... maintain documentation on the creation and retention of (a) Total jobs, (b) number of jobs within certain... that the State shall report and maintain documentation on the creation and retention of total jobs, the... salaries or wages per job and the income limits for a household of one, rather than the usual CDBG standard...

40 CFR 80.581 - What are the batch testing and sample retention requirements for motor vehicle diesel fuel, NRLM...

Code of Federal Regulations, 2011 CFR

2011-07-01

... retention requirements for motor vehicle diesel fuel, NRLM diesel fuel, and ECA marine fuel? 80.581 Section...) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel... requirements for motor vehicle diesel fuel, NRLM diesel fuel, and ECA marine fuel? (a) Beginning on June 1...

40 CFR 80.581 - What are the batch testing and sample retention requirements for motor vehicle diesel fuel, NRLM...

Code of Federal Regulations, 2010 CFR

2010-07-01

... retention requirements for motor vehicle diesel fuel, NRLM diesel fuel, and ECA marine fuel? 80.581 Section...) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel... requirements for motor vehicle diesel fuel, NRLM diesel fuel, and ECA marine fuel? (a) Beginning on June 1...

Development of autoclavable addition type polyimides

NASA Technical Reports Server (NTRS)

Jones, R. J.; Vaughan, R. W.; Orell, M. K.; Sheppard, C. H.

1974-01-01

Two highly promising approaches to yield autoclavable addition-type polyimides were identified and evaluated in the program. Conditions were established for autoclave preparation of Hercules HMS graphite fiber reinforced composites in the temperature range of 473 K to 505 K under an applied pressure of 0.7 MN/m2 (100 psi) for time durations up to four hours. Upon oven postcure in air at 589 K, composite samples demonstrated high mechanical property retention at 561 K after isothermal aging in air for 1000 hours. Promise was shown for shorter term mechanical property retention at 589 K upon exposure in air at this temperature.

A mass-balanced definition of corrected retention volume in gas chromatography.

PubMed

Kurganov, A

2007-05-25

The mass balance equation of a chromatographic system using a compressible moving phase has been compiled for mass flow of the mobile phase instead of traditional volumetric flow allowing solution of the equation in an analytical form. The relation obtained correlates retention volume measured under ambient conditions with the partition coefficient of the solute. Compared to the relation in the ideal chromatographic system the equation derived contains an additional correction term accounting for the compressibility of the moving phase. When the retention volume is measured under the mean column pressure and column temperature the correction term is reduced to unit and the relation is simplified to those known for the ideal system. This volume according to International Union of Pure and Applied Chemistry (IUPAC) is called the corrected retention volume.

Developmental gene regulatory network architecture across 500 million years of echinoderm evolution

NASA Technical Reports Server (NTRS)

Hinman, Veronica F.; Nguyen, Albert T.; Cameron, R. Andrew; Davidson, Eric H.

2003-01-01

Evolutionary change in morphological features must depend on architectural reorganization of developmental gene regulatory networks (GRNs), just as true conservation of morphological features must imply retention of ancestral developmental GRN features. Key elements of the provisional GRN for embryonic endomesoderm development in the sea urchin are here compared with those operating in embryos of a distantly related echinoderm, a starfish. These animals diverged from their common ancestor 520-480 million years ago. Their endomesodermal fate maps are similar, except that sea urchins generate a skeletogenic cell lineage that produces a prominent skeleton lacking entirely in starfish larvae. A relevant set of regulatory genes was isolated from the starfish Asterina miniata, their expression patterns determined, and effects on the other genes of perturbing the expression of each were demonstrated. A three-gene feedback loop that is a fundamental feature of the sea urchin GRN for endoderm specification is found in almost identical form in the starfish: a detailed element of GRN architecture has been retained since the Cambrian Period in both echinoderm lineages. The significance of this retention is highlighted by the observation of numerous specific differences in the GRN connections as well. A regulatory gene used to drive skeletogenesis in the sea urchin is used entirely differently in the starfish, where it responds to endomesodermal inputs that do not affect it in the sea urchin embryo. Evolutionary changes in the GRNs since divergence are limited sharply to certain cis-regulatory elements, whereas others have persisted unaltered.

Attentive Tracking Disrupts Feature Binding in Visual Working Memory

PubMed Central

Fougnie, Daryl; Marois, René

2009-01-01

One of the most influential theories in visual cognition proposes that attention is necessary to bind different visual features into coherent object percepts (Treisman & Gelade, 1980). While considerable evidence supports a role for attention in perceptual feature binding, whether attention plays a similar function in visual working memory (VWM) remains controversial. To test the attentional requirements of VWM feature binding, here we gave participants an attention-demanding multiple object tracking task during the retention interval of a VWM task. Results show that the tracking task disrupted memory for color-shape conjunctions above and beyond any impairment to working memory for object features, and that this impairment was larger when the VWM stimuli were presented at different spatial locations. These results demonstrate that the role of visuospatial attention in feature binding is not unique to perception, but extends to the working memory of these perceptual representations as well. PMID:19609460

Mate retention behavior of men and women in heterosexual and homosexual relationships.

PubMed

Vanderlaan, Doug P; Vasey, Paul L

2008-08-01

Comparing the behavior of heterosexual and homosexual persons can provide insight into the origins of heterosexual sex differences in psychology. Evidence indicates that, aside from sexual partner preference, the mating psychology of homosexual men is sex-typical whereas that of homosexual women tends to be more sex-atypical. The current study examined one aspect of mating psychology, mate retention behavior, and tested whether homosexual men and women were sex-typical or sex-atypical for those mate retention tactics where heterosexual men and women differed. Men and women in heterosexual and homosexual relationships were asked to provide information regarding their partners' mate retention behavior by using the Mate Retention Inventory Questionnaire. Heterosexual men and women differed significantly for six of the 19 mate retention tactics considered. With respect to the six mate retention tactics where heterosexual sex differences existed, homosexual men behaved in a sex-typical manner for five of the tactics, whereas homosexual women behaved in a sex-atypical manner for all six tactics. We discuss the significance of these findings for explaining the origins of the mate retention behavior of heterosexual men and women. In addition, we consider what the pattern of sex-typical and sex-atypical mating psychology among homosexual men and women, respectively, suggests in regard to sex differences in the development of mating psychology and the development of homosexual persons.

The interrelated effect of sleep and learning in dogs (Canis familiaris); an EEG and behavioural study

PubMed Central

Kis, Anna; Szakadát, Sára; Gácsi, Márta; Kovács, Enikő; Simor, Péter; Török, Csenge; Gombos, Ferenc; Bódizs, Róbert; Topál, József

2017-01-01

The active role of sleep in memory consolidation is still debated, and due to a large between-species variation, the investigation of a wide range of different animal species (besides humans and laboratory rodents) is necessary. The present study applied a fully non-invasive methodology to study sleep and memory in domestic dogs, a species proven to be a good model of human awake behaviours. Polysomnography recordings performed following a command learning task provide evidence that learning has an effect on dogs’ sleep EEG spectrum. Furthermore, spectral features of the EEG were related to post-sleep performance improvement. Testing an additional group of dogs in the command learning task revealed that sleep or awake activity during the retention interval has both short- and long-term effects. This is the first evidence to show that dogs’ human-analogue social learning skills might be related to sleep-dependent memory consolidation. PMID:28165489

Preparation of pH-sensitive zwitterionic nano micelles and drug controlled release for enhancing cellular uptake.

PubMed

Wu, Luyan; Ni, Caihua; Zhang, Liping; Shi, Gang

2016-01-01

Zwitterionic copolymers have exhibited high resistance to nonspecific protein adsorption and have wide applications in drug delivery systems. Herein, a pH-responsive poly(Lysine-alt-N,N'-bis(acryloyl) diaminohexane) was synthesized through the Michael addition polymerization between N, N'-bis(acryloyl) diaminohexane and lysine. Subsequently, nano micelles (NMs) were formed by self-assembly of the copolymer in an aqueous solution. The NMs showed a slightly negative charge in blood environment, but a positively charged surface in extracellular pH of tumor. This feature could be used to enhance permeability and retention effect, and reinforce tumor cell uptake. Vitro release studies revealed that the release of DOX from the DOX-loaded NMs was evidently faster at pH 5.0 than at pH 7.4. MTT assays revealed that NMs were nontoxic. Thus, these smart NMs were feasible candidates and could be potentially used in cancer chemotherapy.

Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion

PubMed Central

Tapanila, Leif; Pruitt, Jesse; Pradel, Alan; Wilga, Cheryl D.; Ramsay, Jason B.; Schlader, Robert; Didier, Dominique A.

2013-01-01

New CT scans of the spiral-tooth fossil, Helicoprion, resolve a longstanding mystery concerning the form and phylogeny of this ancient cartilaginous fish. We present the first three-dimensional images that show the tooth whorl occupying the entire mandibular arch, and which is supported along the midline of the lower jaw. Several characters of the upper jaw show that it articulated with the neurocranium in two places and that the hyomandibula was not part of the jaw suspension. These features identify Helicoprion as a member of the stem holocephalan group Euchondrocephali. Our reconstruction illustrates novel adaptations, such as lateral cartilage to buttress the tooth whorl, which accommodated the unusual trait of continuous addition and retention of teeth in a predatory chondrichthyan. Helicoprion exemplifies the climax of stem holocephalan diversification and body size in Late Palaeozoic seas, a role dominated today by sharks and rays. PMID:23445952

The intrinsic role of membrane morphology to reduce defectivity in advanced photochemicals

NASA Astrophysics Data System (ADS)

Kohyama, Tetsu; Wu, Aiwen; Miura, Kozue; Ohyashiki, Yasushi

2018-03-01

Defect source reduction in leading-edge iArF resists is a critical requirement to improve device performance and overall yield in lithography manufacturing processes. It is believed that some polar polymers can aggregate and be responsible for single or multiple micro-bridge defects. Further investigation into the formation of these defects is needed. We have previously presented the effective removal of gel-like polymers using nylon media [1]. However, as the industry is moving to smaller feature sizes, there is a need to further improve the defect removal efficiency. In this paper, a filter, comprised of a novel membrane called Azora with unique morphology and high flow performance is introduced. This new filter shows better on-wafer in an advanced ArF solution than conventional Nylon and UPE media. In addition, it shows improved stability during chemical storage. Results and possible retention mechanisms are discussed.

Rugged large volume injection for sensitive capillary LC-MS environmental monitoring

NASA Astrophysics Data System (ADS)

Roberg-Larsen, Hanne; Abele, Silvija; Demir, Deniz; Dzabijeva, Diana; Amundsen, Sunniva F.; Wilson, Steven R.; Bartkevics, Vadims; Lundanes, Elsa

2017-08-01

A rugged and high throughput capillary column (cLC) LC-MS switching platform using large volume injection and on-line automatic filtration and filter back-flush (AFFL) solid phase extraction (SPE) for analysis of environmental water samples with minimal sample preparation is presented. Although narrow columns and on-line sample preparation are used in the platform, high ruggedness is achieved e.g. injection of 100 non-filtrated water samples would did not result in a pressure rise/clogging of the SPE/capillary columns (inner diameter 300 µm). In addition, satisfactory retention time stability and chromatographic resolution were also features of the system. The potential of the platform for environmental water samples was demonstrated with various pharmaceutical products, which had detection limits (LOD) in the 0.05 - 12.5 ng/L range. Between-day and within-day repeatability of selected analytes were < 20% RSD.

Enhancing nitrification at low temperature with zeolite in a mining operations retention pond.

PubMed

Miazga-Rodriguez, Misha; Han, Sukkyun; Yakiwchuk, Brian; Wei, Kai; English, Colleen; Bourn, Steven; Bohnert, Seth; Stein, Lisa Y

2012-01-01

Ammonium nitrate explosives are used in mining operations at Diavik Diamond Mines Inc. in the Northwest Territories, Canada. Residual nitrogen is washed into the mine pit and piped to a nearby retention pond where its removal is accomplished by microbial activity prior to a final water treatment step and release into the sub-Arctic lake, Lac de Gras. Microbial removal of ammonium in the retention pond is rapid during the brief ice-free summer, but often slows under ice cover that persists up to 9 months of the year. The aluminosilicate mineral zeolite was tested as an additive to retention pond water to increase rates of ammonium removal at 4°C. Water samples were collected across the length of the retention pond monthly over a year. The structure of the microbial community (bacteria, archaea, and eukarya), as determined by denaturing gradient gel electrophoresis of PCR-amplified small subunit ribosomal RNA genes, was more stable during cold months than during July-September, when there was a marked phytoplankton bloom. Of the ammonia-oxidizing community, only bacterial amoA genes were consistently detected. Zeolite (10 g) was added to retention pond water (100 mL) amended with 5 mM ammonium and incubated at 12°C to encourage development of a nitrifying biofilm. The biofilm community was composed of different amoA phylotypes from those identified in gene clone libraries of native water samples. Zeolite biofilm was added to fresh water samples collected at different times of the year, resulting in a significant increase in laboratory measurements of potential nitrification activity at 4°C. A significant positive correlation between the amount of zeolite biofilm and potential nitrification activity was observed; rates were unaffected in incubations containing 1-20 mM ammonium. Addition of zeolite to retention ponds in cold environments could effectively increase nitrification rates year-round by concentrating active nitrifying biomass.

New mini dental implant attachments versus O-ring attachment after cyclic aging: Analysis of retention strength and gap space.

PubMed

Fatalla, Abdalbseet A; Song, Ke; Cao, Ying-Guang

2017-06-01

Overdenture as a treatment modality for both partially and fully edentulous patients is costeffective and less expensive. The purpose of the present study was to examine the newly fabricated attachments by comparing them with conventional O-ring attachment in vitro in terms of retention force and cyclic aging resistance. A total of 150 samples were prepared and divided into five groups according to the materials used (O-ring attachment, Deflex M10 XR, Deflex Classic SR, Deflex Acrilato FD, and flexible acrylic resin). The retention force of different attachments was measured by a mini dental implant after three subsequent aging (0, 63, and 126) cycles in the circumstances similar to the oral environment. The gap space between the head of the implant and the inner surface of the attachments was detected. Two-way analysis of variance (ANOVA) analysis with multiple comparisons test was applied for statistical analysis. The results showed that Deflex M10 XR had the highest retention force and the lowest gap space after cyclic aging; in addition, by comparing the relative force reduction, the lowest values were obtained in the O-ring attachment and the highest values in the flexible acrylic resin attachment. The retention force measured after cyclic aging for the Deflex M10 XR attachment was greatly improved when compared with the O-ring attachment and other types of attachment materials; in addition, the Deflex M10 XR attachment exhibited the minimum gap space between the inner surface and the mini dental implant head. In conclusion, Deflex M10 XR has the ability to withstand weathering conditions and retains its durable and retentive properties after aging when compared with other attachments.

Retention behavior of lipids in reversed-phase ultrahigh-performance liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Ovčačíková, Magdaléna; Lísa, Miroslav; Cífková, Eva; Holčapek, Michal

2016-06-10

Reversed-phase ultrahigh-performance liquid chromatography (RP-UHPLC) method using two 15cm sub-2μm particles octadecylsilica gel columns is developed with the goal to separate and unambiguously identify a large number of lipid species in biological samples. The identification is performed by the coupling with high-resolution tandem mass spectrometry (MS/MS) using quadrupole - time-of-flight (QTOF) instrument. Electrospray ionization (ESI) full scan and tandem mass spectra are measured in both polarity modes with the mass accuracy better than 5ppm, which provides a high confidence of lipid identification. Over 400 lipid species covering 14 polar and nonpolar lipid classes from 5 lipid categories are identified in total lipid extracts of human plasma, human urine and porcine brain. The general dependences of relative retention times on relative carbon number or relative double bond number are constructed and fit with the second degree polynomial regression. The regular retention patterns in homologous lipid series provide additional identification point for UHPLC/MS lipidomic analysis, which increases the confidence of lipid identification. The reprocessing of previously published data by our and other groups measured in the RP mode and ultrahigh-performance supercritical fluid chromatography on the silica column shows more generic applicability of the polynomial regression for the description of retention behavior and the prediction of retention times. The novelty of this work is the characterization of general trends in the retention behavior of lipids within logical series with constant fatty acyl length or double bond number, which may be used as an additional criterion to increase the confidence of lipid identification. Copyright © 2016 Elsevier B.V. All rights reserved.

Mathematical models of ABE fermentation: review and analysis.

PubMed

Mayank, Rahul; Ranjan, Amrita; Moholkar, Vijayanand S

2013-12-01

Among different liquid biofuels that have emerged in the recent past, biobutanol produced via fermentation processes is of special interest due to very similar properties to that of gasoline. For an effective design, scale-up, and optimization of the acetone-butanol-ethanol (ABE) fermentation process, it is necessary to have insight into the micro- and macro-mechanisms of the process. The mathematical models for ABE fermentation are efficient tools for this purpose, which have evolved from simple stoichiometric fermentation equations in the 1980s to the recent sophisticated and elaborate kinetic models based on metabolic pathways. In this article, we have reviewed the literature published in the area of mathematical modeling of the ABE fermentation. We have tried to present an analysis of these models in terms of their potency in describing the overall physiology of the process, design features, mode of operation along with comparison and validation with experimental results. In addition, we have also highlighted important facets of these models such as metabolic pathways, basic kinetics of different metabolites, biomass growth, inhibition modeling and other additional features such as cell retention and immobilized cultures. Our review also covers the mathematical modeling of the downstream processing of ABE fermentation, i.e. recovery and purification of solvents through flash distillation, liquid-liquid extraction, and pervaporation. We believe that this review will be a useful source of information and analysis on mathematical models for ABE fermentation for both the appropriate scientific and engineering communities.

An Experimental Study on the Impact of Different-frequency Elastic Waves on Water Retention Curve

NASA Astrophysics Data System (ADS)

Deng, J. H.; Dai, J. Y.; Lee, J. W.; Lo, W. C.

2017-12-01

ABSTEACTOver the past few decades, theoretical and experimental studies on the connection between elastic wave attributes and the physical properties of a fluid-bearing porous medium have attracted the attention of many scholars in fields of porous medium flow and hydrogeology. It has been previously determined that the transmission of elastic waves in a porous medium containing two immiscible fluids will have an effect on the water retention curve, but it has not been found that the water retention curve will be affected by the frequency of elastic vibration waves or whether the effect on the soil is temporary or permanent. This research is based on a sand box test in which the soil is divided into three layers (a lower, middle, and upper layer). In this case, we discuss different impacts on the water retention curve during the drying process under sound waves (elastic waves) subject to three frequencies (150Hz, 300Hz, and 450Hz), respectively. The change in the water retention curve before and after the effect is then discussed. In addition, how sound waves affect the water retention curve at different depths is also observed. According to the experimental results, we discover that sound waves can cause soil either to expand or to contract. When the soil is induced to expand due to sound waves, it can contract naturally and return to the condition it was in before the influence of the sound waves. On the contrary, when the soil is induced to contract, it is unable to return to its initial condition. Due to the results discussed above, it is suggested that sound waves causing soil to expand have a temporary impact while those causing soil to contract have a permanent impact. In addition, our experimental results show how sound waves affect the water retention curve at different depths. The degree of soil expansion and contraction caused by the sound waves will differ at various soil depths. Nevertheless, the expanding or contracting of soil is only subject to the frequency of sound waves. Key words: Elastic waves, Water retention curve, Sand box test.

Pay-for-performance in a community substance abuse clinic

PubMed Central

Vandrey, Ryan; Stitzer, Maxine L.; Acquavita, Shauna P.; Quinn-Stabile, Patricia

2011-01-01

Pay-for-performance (P4P) strategies improve employee productivity and morale in business settings and are increasingly being implemented in medical care settings. This study investigated whether P4P could improve treatment utilization and retention at a community drug treatment clinic. Counselors had the opportunity to earn cash bonuses based on therapy attendance rates of individual clients as well as the quarterly retention rates of their caseload. Using a pre-post study design, average therapy sessions attended during the first month of treatment increased from 4.6 sessions prior to the intervention to 5.5 sessions per client during the intervention. The 90-day client retention rate increased from 40% to 53%. Additional analyses suggest that the improvement in 90-day retention was mediated by the increase in attendance during the first month of treatment. This project demonstrates that implementing a P4P incentive program in community drug abuse treatment clinics is feasible and effective at improving utilization and retention. PMID:21489739

Fastener load tests and retention systems tests for cryogenic wind-tunnel models

NASA Technical Reports Server (NTRS)

Wallace, J. W.

1984-01-01

A-286 stainless steel screws were tested to determine the tensile load capability and failure mode of various screw sizes and types at both cryogenic and room temperature. Additionally, five fastener retention systems were tested by using A-286 screws with specimens made from the primary metallic alloys that are currently used for cryogenic models. The locking system effectiveness was examined by simple no-load cycling to cryogenic temperatures (-275 F) as well as by dynamic and static loading at cryogenic temperatures. In general, most systems were found to be effective retention devices. There are some differences between the various devices with respect to ease of application, cleanup, and reuse. Results of tests at -275 F imply that the cold temperatures act to improve screw retention. The improved retention is probably the result of differential thermal contraction and/or increased friction (thread-binding effects). The data provided are useful in selecting screw sizes, types, and locking devices for model systems to be tested in cryogenic wind tunnels.

A hydrologic retention system and water quality monitoring program for a human decomposition research facility: concept and design.

PubMed

Wozniak, Jeffrey R; Thies, Monte L; Bytheway, Joan A; Lutterschmidt, William I

2015-01-01

Forensic taphonomy is an essential research field; however, the decomposition of human cadavers at forensic science facilities may lead to nutrient loading and the introduction of unique biological compounds to adjacent areas. The infrastructure of a water retention system may provide a mechanism for the biogeochemical processing and retention of nutrients and compounds, ensuring the control of runoff from forensic facilities. This work provides a proof of concept for a hydrologic retention system and an autonomous water quality monitoring program designed to mitigate runoff from The Southeast Texas Applied Forensic Science (STAFS) Facility. Water samples collected along a sample transect were analyzed for total phosphorous, total nitrogen, NO3-, NO2-, NH4, F(-), and Cl(-). Preliminary water quality analyses confirm the overall effectiveness of the water retention system. These results are discussed with relation to how this infrastructure can be expanded upon to monitor additional, more novel, byproducts of forensic science research facilities. © 2014 American Academy of Forensic Sciences.

Characterization of aromatic residue-controlled protein retention in the endoplasmic reticulum of Saccharomyces cerevisiae.

PubMed

Mei, Meng; Zhai, Chao; Li, Xinzhi; Zhou, Yu; Peng, Wenfang; Ma, Lixin; Wang, Qinhong; Iverson, Brent L; Zhang, Guimin; Yi, Li

2017-12-15

An endoplasmic reticulum (ER) retention sequence (ERS) is a characteristic short sequence that mediates protein retention in the ER of eukaryotic cells. However, little is known about the detailed molecular mechanism involved in ERS-mediated protein ER retention. Using a new surface display-based fluorescence technique that effectively quantifies ERS-promoted protein ER retention within Saccharomyces cerevisiae cells, we performed comprehensive ERS analyses. We found that the length, type of amino acid residue, and additional residues at positions -5 and -6 of the C-terminal HDEL motif all determined the retention of ERS in the yeast ER. Moreover, the biochemical results guided by structure simulation revealed that aromatic residues (Phe-54, Trp-56, and other aromatic residues facing the ER lumen) in both the ERS (at positions -6 and -4) and its receptor, Erd2, jointly determined their interaction with each other. Our studies also revealed that this aromatic residue interaction might lead to the discriminative recognition of HDEL or KDEL as ERS in yeast or human cells, respectively. Our findings expand the understanding of ERS-mediated residence of proteins in the ER and may guide future research into protein folding, modification, and translocation affected by ER retention. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Advanced Gas Turbine (AGT) technology development

NASA Technical Reports Server (NTRS)

1983-01-01

A 74.5 kW (100 hp) automotive gas turbine was evaluated. The engine structure, bearings, oil system, and electronics were demonstrated and no shaft dynamics or other vibration problem were encountered. Areas identified during the five tests are the scroll retention features, and transient thermal deflection of turbine backplates. Modifications were designed. Seroll retention is addressed by modifying the seal arrangement in front of the gasifier turbine assembly, which will increase the pressure load on the scroll in the forward direction and thereby increase the retention forces. the backplate thermal deflection is addressed by geometric changes and thermal insulation to reduce heat input. Combustor rig proof testing of two ceramic combustor assemblies was completed. The combustor was modified to incorporate slots and reduce sharp edges, which should reduce thermal stresses. The development work focused on techniques to sinter these barrier materials onto the ceramic rotors with successes for both material systems. Silicon carbide structural parts, including engine configuration gasifier rotors (ECRs), preliminary gasifier scroll parts, and gasifier and power turbine vanes are fabricated.

Fast, axis-agnostic, dynamically summarized storage and retrieval for mass spectrometry data.

PubMed

Handy, Kyle; Rosen, Jebediah; Gillan, André; Smith, Rob

2017-01-01

Mass spectrometry, a popular technique for elucidating the molecular contents of experimental samples, creates data sets comprised of millions of three-dimensional (m/z, retention time, intensity) data points that correspond to the types and quantities of analyzed molecules. Open and commercial MS data formats are arranged by retention time, creating latency when accessing data across multiple m/z. Existing MS storage and retrieval methods have been developed to overcome the limitations of retention time-based data formats, but do not provide certain features such as dynamic summarization and storage and retrieval of point meta-data (such as signal cluster membership), precluding efficient viewing applications and certain data-processing approaches. This manuscript describes MzTree, a spatial database designed to provide real-time storage and retrieval of dynamically summarized standard and augmented MS data with fast performance in both m/z and RT directions. Performance is reported on real data with comparisons against related published retrieval systems.

A Comparison of the J-1 Visa Waiver and Loan Repayment Programs in the Recruitment and Retention of Physicians in Rural Nebraska.

PubMed

Opoku, Samuel T; Apenteng, Bettye A; Lin, Ge; Chen, Li-Wu; Palm, David; Rauner, Thomas

2015-01-01

There is a dearth of literature evaluating the effectiveness of programs aimed at recruiting and retaining physicians in rural Nebraska. Taking advantage of the Nebraska Health Professional Tracking System, this study attempts to comparatively assess the effectiveness of the J-1 visa waiver and state loan repayment programs in the recruitment and retention of physicians in rural Nebraska. A mixed methods approach was used. We tracked 240 physicians who enrolled in the J-1 visa waiver and state loan repayment programs between 1996 and 2012 until 2013. In addition, key informant interviews were conducted to obtain perspectives on the recruitment and retention of physicians in rural Nebraska through the 2 programs. Results from multilevel survival regression analysis indicated that physicians enrolled in the J-1 visa waiver program were more likely to leave rural Nebraska when compared with those enrolled in the state loan repayment program. Participants in the qualitative study, however, cautioned against declaring one program as superior over the other, given that the 2 programs addressed different needs for different communities. In addition, results suggested that fostering the integration of physicians and their families into rural communities might be a way of enhancing retention, regardless of program. The findings from this study highlight the complexity of recruitment and retention issues in rural Nebraska and suggest the need for more holistic and family-centered approaches to addressing these issues. © 2015 National Rural Health Association.

The effect of additives on release and in vitro skin retention of flavonoids from emulsion and gel semisolid formulations.

PubMed

Dyja, R; Jankowski, A

2017-08-01

To assess the effect of two different additives (propylene glycol (PG) and polyethylene glycol 400 (PEG 400)) on release and in vitro skin retention of quercetin and chrysin from semisolid bases (amphiphilic creams and acidic carbomer gels). For obtaining semisolid formulations, flavonoids were pre-dissolved in the liquid (PG or PEG 400) or directly suspended in the semisolid base. Three chrysin formulations ('cream 0', 'PG-cream' and 'PEG 400-cream') and five quercetin formulations ('cream 0', 'PG cream', 'PEG 400 cream', 'gel 0' and 'PG gel') were prepared. The release studies were carried out in Franz diffusion cells by means of a cellulose membrane. The porcine ear skin was used in in vitro skin retention studies. The dissolution was a prerequisite to increase the release rates of tested flavonoids from obtained semisolid formulations. The cumulative amount of chrysin released after 6 h from 'PEG 400 cream' containing partly dissolved form of that flavonoid was higher than that from 'cream 0' or 'PG cream' containing its suspended form. The formulations containing quercetin dissolved in PG ('PG cream', 'PG gel') or PEG 400 ('PEG 400 cream') exhibited higher release rates of that flavonoid than corresponding semisolid suspensions ('cream 0' or 'gel 0'). The effects of both liquid additives (PG and PEG 400) on the cumulative amount of quercetin released after 6 h were comparable. However, there was no correlation between the release rate and the skin retention. The amounts of the flavonoids found in the skin were strongly affected by the type of the used solvent. While PG increased the skin retention of both flavonoids, PEG 400 had no effect on chrysin skin retention and delayed quercetin skin absorption. The proper choice of the solvent added to the semisolid base is crucial for enhanced skin delivery of the tested flavonoids. PG is more efficient absorption promoter than PEG 400 of both chrysin and quercetin. © 2017 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

HESS Opinions Catchments as meta-organisms - a new blueprint for hydrological modelling

NASA Astrophysics Data System (ADS)

Savenije, Hubert H. G.; Hrachowitz, Markus

2017-02-01

Catchment-scale hydrological models frequently miss essential characteristics of what determines the functioning of catchments. The most important active agent in catchments is the ecosystem. It manipulates and partitions moisture in a way that supports the essential functions of survival and productivity: infiltration of water, retention of moisture, mobilization and retention of nutrients, and drainage. Ecosystems do this in the most efficient way, establishing a continuous, ever-evolving feedback loop with the landscape and climatic drivers. In brief, hydrological systems are alive and have a strong capacity to adjust themselves to prevailing and changing environmental conditions. Although most models take Newtonian theory at heart, as best they can, what they generally miss is Darwinian theory on how an ecosystem evolves and adjusts its environment to maintain crucial hydrological functions. In addition, catchments, such as many other natural systems, do not only evolve over time, but develop features of spatial organization, including surface or sub-surface drainage patterns, as a by-product of this evolution. Models that fail to account for patterns and the associated feedbacks miss a critical element of how systems at the interface of atmosphere, biosphere and pedosphere function. In contrast to what is widely believed, relatively simple, semi-distributed conceptual models have the potential to accommodate organizational features and their temporal evolution in an efficient way, a reason for that being that because their parameters (and their evolution over time) are effective at the modelling scale, and thus integrate natural heterogeneity within the system, they may be directly inferred from observations at the same scale, reducing the need for calibration and related problems. In particular, the emergence of new and more detailed observation systems from space will lead towards a more robust understanding of spatial organization and its evolution. This will further permit the development of relatively simple time-dynamic functional relationships that can meaningfully represent spatial patterns and their evolution over time, even in poorly gauged environments.

Factors affecting the removal of ammonia from air on carbonaceous materials: Investigation of reactive adsorption mechanism

NASA Astrophysics Data System (ADS)

Petit, Camille

Air pollution related to the release of industrial toxic gases, represents one of the main concerns of our modern world owing to its detrimental effect on the environment. To tackle this growing issue, efficient ways to reduce/control the release of pollutants are required. Adsorption of gases on porous materials appears as a potential solution. However, the physisorption of small molecules of gases such as ammonia is limited at ambient conditions. For their removal, adsorbents providing strong adsorption forces must be used/developed. In this study, new carbon-based materials are prepared and tested for ammonia adsorption at ambient conditions. Characterization of the adsorbents' texture and surface chemistry is performed before and after exposure to ammonia to identify the features responsible for high adsorption capacity and for controlling the mechanisms of retention. The characterization techniques include: nitrogen adsorption, thermal analysis, potentiometric titration, FT-IR spectroscopy, X-ray diffraction, Energy Dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and Electron Microscopy. The results obtained indicate that ammonia removal is governed by the adsorbent's surface chemistry. On the contrary, porosity (and thus physisorption) plays a secondary role in this process, unless strong dispersive forces are provided by the adsorbent. The surface chemistry features responsible for the enhanced ammonia adsorption include the presence of oxygen-(carboxyl, hydroxyl, epoxy) and sulfur- (sulfonic) containing groups. Metallic species improve the breakthrough capacity as well as they lead to the formation of Lewis acid-base interactions, hydrogen-bonding or complexation. In addition to the latter three mechanisms, ammonia is retained on the adsorbent surface via Bronsted acid-base interactions or via specific reactions with the adsorbent's functionalities leading to the incorporation of ammonia into the adsorbent's matrix. Another mechanism involves dissolution of ammonia in water when moisture is present in the system. Even though this process increases the breakthrough capacity of a material, it provides rather weak retention forces since ammonia dissolved in water is easily desorbed from the adsorbent's surface.

High Stakes Testing in Lower-Performing High Schools: Mathematics Teachers' Perceptions of Burnout and Retention

ERIC Educational Resources Information Center

Kirtley, Karmen

2012-01-01

This dissertation grows from a concern that the current public school accountability model, designed ostensibly to increase achievement in lower-performing schools, may be creating unidentified negative consequences for teachers and students within those schools. This hermeneutical phenomenological study features the perceptions of seventeen…

Biochar impact on improving root growth and water retention capacity in Norfolk hard setting subsoil layer

USDA-ARS?s Scientific Manuscript database

The Norfolk soil series is a well-drained soil used commonly for agricultural production in the Eastern Carolinas. Certain profile features such as a hard setting subsoil layer with high bulk density, low water holding capacity and meager soil fertility characteristics makes this soil less producti...

Daytime encopresis associated with gland mal epileptic seizures: case report.

PubMed

Oyatsi, D P

2005-08-01

Sphincteric incontinence of stool and urine are not unusual features of generalised epileptic seizures. Isolated secondary encopresis as a manifestation of an epileptic seizure is unusual. This report is of, a four year old boy, with daytime secondary non-retentive encopresis. The onset of encopresis was preceded by several episodes of nocturnal generalised tonic clonic epileptic seizures. An electroencephalogram showed features consistent with complex partial seizures. He was commenced on anti-epileptic treatment with phenytoin sodium, and by the third day of treatment, the patient had achieved stool control.

Physiological remodeling of bifurcation aneurysms: preclinical results of the eCLIPs device.

PubMed

Marotta, Thomas R; Riina, Howard A; McDougall, Ian; Ricci, Donald R; Killer-Oberpfalzer, Monika

2018-02-01

OBJECTIVE Intracranial bifurcation aneurysms are complex lesions for which current therapy, including simple coiling, balloon- or stent-assisted coiling, coil retention, or intrasaccular devices, is inadequate. Thromboembolic complications due to a large burden of intraluminal metal, impedance of access to side branches, and a high recurrence rate, due largely to the unmitigated high-pressure flow into the aneurysm (water hammer effect), are among the limitations imposed by current therapy. The authors describe herein a novel device, eCLIPs, and its use in a preclinical laboratory study that suggests the device's design and functional features may overcome many of these limitations. METHODS A preclinical model of wide-necked bifurcation aneurysms in rabbits was used to assess functional features and efficacy of aneurysm occlusion by the eCLIPs device. RESULTS The eCLIPs device, in bridging the aneurysm neck, allows coil retention, disrupts flow away from the aneurysm, leaves the main vessel and side branches unencumbered by intraluminal metal, and serves as a platform for endothelial growth across the neck, excluding the aneurysm from the circulation. CONCLUSIONS The eCLIPs device permits physiological remodeling of the bifurcation.

NASA records retention schedules: Procedures governing the retention, retirement, and destruction of agency records

NASA Technical Reports Server (NTRS)

1994-01-01

This handbook sets forth the minimum retention periods of official records of NASA. Its provisions are applicable to NASA Headquarters and all field installations. This revised edition has been correlated to the 'NASA Uniform Files Index (UFI) (NHB 1442.1B), the General Records Schedules' produced by the National Archives and Records Administration (NARA), and has been enlarged in scope to cover Privacy Act Systems of Records and record series previously omitted. Guidance is provided in the areas of record retirement, transfer, and retrieval from Federal Record Centers (FRC) and disposal actions. Included are provisions for making changes to these schedules by addition of new items or revision of current items. The NASA Records Retention Schedules (NRRS) were approved for NASA use by NARA, the General Services Administration, and the General Accounting Office.

Metal retention in human transferrin: consequences of solvent composition in analytical sample preparation methods.

PubMed

Quarles, C Derrick; Randunu, K Manoj; Brumaghim, Julia L; Marcus, R Kenneth

2011-10-01

The analysis of metal-binding proteins requires careful sample manipulation to ensure that the metal-protein complex remains in its native state and the metal retention is preserved during sample preparation or analysis. Chemical analysis for the metal content in proteins typically involves some type of liquid chromatography/electrophoresis separation step coupled with an atomic (i.e., inductively coupled plasma-optical emission spectroscopy or -mass spectrometry) or molecular (i.e., electrospray ionization-mass spectrometry) analysis step that requires altered-solvent introduction techniques. UV-VIS absorbance is employed here to monitor the iron content in human holo-transferrin (Tf) under various solvent conditions, changing polarity, pH, ionic strength, and the ionic and hydrophobic environment of the protein. Iron loading percentages (i.e. 100% loading equates to 2 Fe(3+):1 Tf) were quantitatively determined to evaluate the effect of solvent composition on the retention of Fe(3+) in Tf. Maximum retention of Fe(3+) was found in buffered (20 mM Tris) solutions (96 ± 1%). Exposure to organic solvents and deionized H(2)O caused release of ~23-36% of the Fe(3+) from the binding pocket(s) at physiological pH (7.4). Salt concentrations similar to separation conditions used for ion exchange had little to no effect on Fe(3+) retention in holo-Tf. Unsurprisingly, changes in ionic strength caused by additions of guanidine HCl (0-10 M) to holo-Tf resulted in unfolding of the protein and loss of Fe(3+) from Tf; however, denaturing and metal loss was found not to be an instantaneous process for additions of 1-5 M guanidinium to Tf. In contrast, complete denaturing and loss of Fe(3+) was instantaneous with ≥6 M additions of guanidinium, and denaturing and loss of iron from Tf occurred in parallel proportions. Changes to the hydrophobicity of Tf (via addition of 0-14 M urea) had less effect on denaturing and release of Fe(3+) from the Tf binding pocket compared to changes in ionic strength. This journal is © The Royal Society of Chemistry 2011

Predicting Impact of Biochar Addition on Soil Hydraulic Properties

NASA Astrophysics Data System (ADS)

Nakhli, S. A. A.; Yudi, Y.; Imhoff, P. T.

2017-12-01

Biochar has been proposed as a soil amendment to improve soil hydraulic properties, including water retention and saturated and unsaturated hydraulic conductivity, for agricultural and environmental applications. However, its effect on hydraulic properties is difficult to predict and often with mixed results: in some cases biochar enhances soil hydraulic properties, while in other cases it degrades them. Despite several published observational studies, there are no models that can reliably predict biochar's impact on soil hydraulic properties. In this project we developed models to describe the effect of addition of a commercial wood biochar pyrolyzed at 550° on soil hydraulic properties in laboratory-scale experiments. The effects of biochar addition at 2% and 6% (w/w) on water retention and saturated and unsaturated hydraulic conductivity were evaluated for silt loam, sandy loam, and loamy sand. The addition of 6% (w/w) biochar increased the available water content of silt loam, sandy loam and loamy sand by 25, 20 and 70%, respectively. The impact of biochar addition on water retention was predicted reasonably well using information on the intra particle pore volume of biochar (mercury porosimetry, N2 and CO2 sorption) and the particle size distribution of the soil/biochar mixture. When amended with 6% biochar, saturated hydraulic conductivity increased 17% for loamy sand, but decreased 30% and 54% for silt loam and sandy loam, respectively. The Kozeny-Carman equation modified to account for changes in inter pore volume predicted saturated hydraulic conductivities of the biochar-amended soils reasonably well, with RMSE ranging from 0.06 to 5.06 cm h-1 for silt loam and loamy sand, respectively. While intra particle pore volume of biochar contributed significantly to higher water retention, changes in hydraulic conductivity were correlated instead with changes in inter pore volume - the large pores between biochar and soil particles.

Retentivity, selectivity and thermodynamic behavior of polycyclic aromatic hydrocarbons on charge-transfer and hypercrosslinked stationary phases under conditions of normal phase high performance liquid chromatography.

PubMed

Jiang, Ping; Lucy, Charles A

2016-03-11

Charge-transfer and hypercrosslinked polystyrene phases offer retention and separation for polycyclic aromatic hydrocarbons (PAHs) and thus have potential for petroleum analysis. The size, shape and planarity selectivity for PAH standards on charge-transfer (DNAP column) and hypercrosslinked polystyrene (HC-Tol and 5HGN columns) phases are different under normal phase liquid chromatography (NPLC). The HC-Tol column behaves like a conventional NPLC column with low retention of PAHs. Retention of PAHs on the DNAP and 5HGN are strong and increases with the number of aromatic rings. The main retention mechanism is through π-π interactions and dipole-induced dipole interaction. Thermodynamics indicates that the retention mechanism of PAHs remains unchanged over the temperature range 20-60°C. In addition, on either DNAP or 5HGN column, both linear and bent PAHs are retained through the same mechanism. But DNAP possesses smaller π-π interaction and higher planarity selectivity than 5HGN for PAHs. This is suggestive that DNAP interacts with PAHs through a disordered phase arrangement, while 5HGN behaves as an ordered adsorption phase. Copyright © 2016 Elsevier B.V. All rights reserved.

Liposome retention in size exclusion chromatography

PubMed Central

Ruysschaert, Tristan; Marque, Audrey; Duteyrat, Jean-Luc; Lesieur, Sylviane; Winterhalter, Mathias; Fournier, Didier

2005-01-01

Background Size exclusion chromatography is the method of choice for separating free from liposome-encapsulated molecules. However, if the column is not presaturated with lipids this type of chromatography causes a significant loss of lipid material. To date, the mechanism of lipid retention is poorly understood. It has been speculated that lipid binds to the column material or the entire liposome is entrapped inside the void. Results Here we show that intact liposomes and their contents are retained in the exclusion gel. Retention depends on the pore size, the smaller the pores, the higher the retention. Retained liposomes are not tightly fixed to the beads and are slowly released from the gels upon direct or inverted eluent flow, long washing steps or column repacking. Further addition of free liposomes leads to the elution of part of the gel-trapped liposomes, showing that the retention is transitory. Trapping reversibility should be related to a mechanism of partitioning of the liposomes between the stationary phase, water-swelled polymeric gel, and the mobile aqueous phase. Conclusion Retention of liposomes by size exclusion gels is a dynamic and reversible process, which should be accounted for to control lipid loss and sample contamination during chromatography. PMID:15885140

Chromatographic behavior of zwitterionic enalapril-exploring the conditions for lipophilicity assessment.

PubMed

Gikas, Spyros; Tsopelas, Fotios; Giaginis, Costas; Dimitrakopoulos, John; Livadara, Theodora; Archontaki, Helen; Tsantili-Kakoulidou, Anna

2008-11-04

The chromatographic behavior of enalapril was investigated under different stationary and mobile phase conditions in an effort to unravel interferences in the underlying retention mechanism, which would affect its relation to octanol-water partitioning. Extrapolated retention factors, logk(w), were used as relevant chromatographic indices. The retention/pH profile was established and the peak split phenomenon, associated with cis/trans interconversion, was also monitored as a function of pH. The pH at maximum retention and minimum peak split occurrence was chosen for further investigation, so that the presence of zwitterionic structure was guaranteed and any effect of cis/trans interconversion could be ignored. Retention of zwitterionic enalapril was found to be very sensitive to mobile phase conditions in regard to organic modifier as well to the aqueous component. The use of morpholine-propanesulfonic acid (MOPS) as buffer and the presence of n-octanol as mobile phase additive proved critical factors for maximum suppression of secondary interactions. Nevertheless, the corresponding extrapolated retention factor was considerably larger than octanol-water logD value at the isoelectric point. However, logk(w) could be successfully converted to logD by means of a calibration equation established for ionized acidic compounds.

The visual and radiological inspection of a pipeline using a teleoperated pipe crawler

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

Fogle, R.F.; Kuelske, K.; Kellner, R.

1995-01-01

In the 1950s, the Savannah River Site built an open, unlined retention basin to temporarily store potentially radionuclide contaminated cooling water from a chemical separations process and storm water drainage from a nearby waste management facility that stored large quantities of nuclear fission byproducts in carbon steel tanks. The retention basin was retired from service in 1972 when a new, lined basin was completed. In 1978, the old retention basin was excavated, backfilled with uncontaminated dirt, and covered with grass. At the same time, much of the underground process pipeline leading to the basin was abandoned. Since the closure ofmore » the retention basin, new environmental regulations require that the basin undergo further assessment to determine whether additional remediation is required. A visual and radiological inspection of the pipeline was necessary to aid in the remediation decision making process for the retention basin system. A teleoperated pipe crawler inspection system was developed to survey the abandoned sections of underground pipelines leading to the retired retention basin. This paper will describe the background to this project, the scope of the investigation, the equipment requirements, and the results of the pipeline inspection.« less

The inspection of a radiologically contaminated pipeline using a teleoperated pipe crawler

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

Fogle, R.F.; Kuelske, K.; Kellner, R.A.

1995-08-01

In the 1950s, the Savannah River Site built an open, unlined retention basin to temporarily store potentially radionuclide contaminated cooling water from a chemical separations process and storm water drainage from a nearby waste management facility that stored large quantities of nuclear fission byproducts in carbon steel tanks. The retention basin was retired from service in 1972 when a new, lined basin was completed. In 1978, the old retention basin was excavated, backfilled with uncontaminated dirt, and covered with grass. At the same time, much of the underground process pipeline leading to the basin was abandoned. Since the closure ofmore » the retention basin, new environmental regulations require that the basin undergo further assessment to determine whether additional remediation is required. A visual and radiological inspection of the pipeline was necessary to aid in the remediation decision making process for the retention basin system. A teleoperated pipe crawler inspection system was developed to survey the abandoned sections of underground pipelines leading to the retired retention basin. This paper will describe the background to this project, the scope of the investigation, the equipment requirements, and the results of the pipeline inspection.« less

Analytical Enantioseparation of β-Substituted-2-Phenylpropionic Acids by High-Performance Liquid Chromatography with Hydroxypropyl-β-Cyclodextrin as Chiral Mobile Phase Additive.

PubMed

Tong, Shengqiang; Zhang, Hu; Yan, Jizhong

2016-04-01

Analytical enantioseparation of five β-substituted-2-phenylpropionic acids by high-performance liquid chromatography with hydroxypropyl-β-cyclodextrin (HP-β-CD) as chiral mobile phase additive was established in this paper, and chromatographic retention mechanism was studied. The effects of various factors such as the organic modifier, different ODS C18 columns and concentration of HP-β-CD were investigated. The chiral mobile phase was composed of methanol or acetonitrile and 0.5% triethylamine acetate buffer at pH 3.0 added with 25 mmol L(-1) of HP-β-CD, and baseline separations could be reached for all racemates. As for chromatographic retention mechanism, it was found that there was a negative correlation between the concentration of HP-β-CD in mobile phase and the retention factor under constant pH value and column temperature. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Distress tolerance interacts with circumstances, motivation, and readiness to predict substance abuse treatment retention.

PubMed

Ali, Bina; Green, Kerry M; Daughters, Stacey B; Lejuez, C W

2017-10-01

Our understanding of the conditions that influence substance abuse treatment retention in urban African American substance users is limited. This study examined the interacting effect of circumstances, motivation, and readiness (CMR) with distress tolerance to predict substance abuse treatment retention in a sample of urban African American treatment-seeking substance users. Data were collected from 81 African American substance users entering residential substance abuse treatment facility in an urban setting. Participants completed self-reported measures on CMR and distress tolerance. In addition, participants were assessed on psychiatric comorbidities, substance use severity, number of previous treatments, and demographic characteristics. Data on substance abuse treatment retention were obtained using administrative records of the treatment center. Logistic regression analysis found that the interaction of CMR and distress tolerance was significant in predicting substance abuse treatment retention. Higher score on CMR was significantly associated with increased likelihood of treatment retention in substance users with higher distress tolerance, but not in substance users with lower distress tolerance. Findings of the study indicate that at higher level of distress tolerance, favorable external circumstances, higher internal motivation, and greater readiness to treatment are important indicators of substance abuse treatment retention. The study highlights the need for assessing CMR and distress tolerance levels among substance users entering treatment, and providing targeted interventions to increase substance abuse treatment retention and subsequent recovery from substance abuse among urban African American substance users. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transport and retention of bacteria and viruses in biochar-amended sand.

PubMed

Sasidharan, Salini; Torkzaban, Saeed; Bradford, Scott A; Kookana, Rai; Page, Declan; Cook, Peter G

2016-04-01

The transport and retention of Escherichia coli and bacteriophages (PRD1, MS2 and ФX174), as surrogates for human pathogenic bacteria and viruses, respectively, were studied in the sand that was amended with several types of biochar produced from various feedstocks. Batch and column studies were conducted to distinguish between the role of attachment and straining in microbe retention during transport. Batch experiments conducted at various solution chemistries showed negligible attachment of viruses and bacteria to biochar before or after chemical activation. At any given solution ionic strength, the attachment of viruses to sand was significantly higher than that of biochar, whereas bacteria showed no attachment to either sand or biochar. Consistent with batch results, biochar addition (10% w/w) to sand reduced virus retention in the column experiments, suggesting a potential negative impact of biochar application to soil on virus removal. In contrast, the retention of bacteria was enhanced in biochar-amended sand columns. However, elimination of the fine fraction (<60μm) of biochar particles in biochar-amended sand columns significantly reduced bacteria retention. Results from batch and column experiments suggest that land application of biochar may only play a role in microbe retention via straining, by alteration of pore size distribution, and not via attachment. Consequently, the particle size distribution of biochar and sediments is a more important factor than type of biochar in determining whether land application of biochar enhances or diminishes microbial retention. Copyright © 2016 Elsevier B.V. All rights reserved.

Predictors of Calcium Retention in Adolescent Boys

PubMed Central

Hill, Kathleen M.; Braun, Michelle; Kern, Mark; Martin, Berdine R.; Navalta, James W.; Sedlock, Darlene A.; McCabe, Linda; McCabe, George P.; Peacock, Munro; Weaver, Connie M.

2008-01-01

Context: The relationship between calcium (Ca) intake and Ca retention in adolescent boys was recently reported. Objective: This study evaluated the influence of Ca intake, serum hormone levels, biomarkers of bone metabolism, habitual physical activity, habitual Ca intake, and physical fitness on Ca retention in the same sample. Design: This study was a randomized, cross-over design that consisted of two 3-wk metabolic balance periods. Setting: The study took place on a university campus as a summer camp. Patients or Other Participants: A total of 31 American white boys (13–15 yr) participated in the study. Interventions: Each subject consumed a controlled diet with one of five high-low Ca intake pairs that ranged from 670-2003 mg/d, which was manipulated utilizing a fortified beverage. Main Outcome Measures: Ca retention was determined by Ca intake minus urinary and fecal Ca excretion during each balance period. Results: Ca intake explained 21.7% of the variability in Ca retention, and serum IGF-I concentration explained an additional 11.5%. Other serum hormone levels did not significantly add to the model. Biomarkers of bone metabolism, habitual physical activity, habitual Ca intake, and physical fitness were not significant predictors of Ca retention in adolescent boys. Conclusions: IGF-I, a regulator of growth during puberty, is an important predictor of Ca retention in adolescent boys. However, dietary Ca intake is an even greater predictor of Ca retention during this period of growth. PMID:18840643

300 Area Building Retention Evaluation Mitigation Plan

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

D. J. McBride

2007-07-03

Evaluate the long-term retention of several facilities associated with the PNNL Capability Replacement Laboratory and other Hanfor mission needs. WCH prepared a mitigation plan for three scenarios with different release dates for specific buildings. The evaluations present a proposed plan for providing utility services to retained facilities in support of a long-term (+20 year) lifespan in addition to temporary services to buildings with specified delayed release dates.

Application of Enlisted Force Retention Levels and Career Field Stability

DTIC Science & Technology

2017-03-23

a priority. This research focuses on modeling the enlisted force retention behavior. Specifically, this research examines a statistically based ...and must be manually corrected. Air Force Manpower , Personnel and Services (AF/A1PF) supplied the data used in this research . The data was...Stability Jamie T. Zimmerman Follow this and additional works at: https://scholar.afit.edu/etd Part of the Operational Research Commons This Thesis is

Influence of addition order and contact time on thorium(IV) retention by hematite in the presence of humic acids.

PubMed

Reiller, Pascal; Casanova, Florence; Moulin, Valérie

2005-03-15

The influence of addition order and contact time in the system hematite (alpha-Fe2O3)-humic acid (HA)-thorium(IV) (Th(IV)) was studied in batch experiments. Th(IV) is considered here as a chemical analogue of other actinides (IV). The sorption isotherms were acquired varying pH in the range 2-10 and HA concentration in the range 1-100 mg/L. As already observed by numerous authors, Th(IV) retention was hindered when HA and hematite were equilibrated beforehand during 24 h. As it has been observed in a previous study, this effect was drastic when the ratio between humic and surface (iron oxide) sites exceeds a critical value. However, when HA was added after a 24-h equilibration of the hematite-Th(IV) system, Th(IV) was barely desorbed from the iron oxide surface. Furthermore, no drastic effect of the ratio between humic and surface sites could be evidenced, as the increase of HA concentration only results in a slight monotonic decrease in Th(IV) retention. Increasing contact time between components of the systems only indicated slight Th(IV) retention variation. This was interpreted as a consequence of slow kinetic controls of both the Th(IV)-HA complexation and HA-hematite sorption.

Feature bindings are maintained in visual short-term memory without sustained focused attention.

PubMed

Delvenne, Jean-François; Cleeremans, Axel; Laloyaux, Cédric

2010-01-01

Does the maintenance of feature bindings in visual short-term memory (VSTM) require sustained focused attention? This issue was investigated in three experiments, in which memory for single features (i.e., colors or shapes) was compared with memory for feature bindings (i.e., the link between the color and shape of an object). Attention was manipulated during the memory retention interval with a retro-cue, which allows attention to be directed and focused on a subset of memory items. The retro-cue was presented 700 ms after the offset of the memory display and 700 ms before the onset of the test display. If the maintenance of feature bindings - but not of individual features - in memory requires sustained focused attention, the retro-cue should not affect memory performance. Contrary to this prediction, we found that both memory for feature bindings and memory for individual features were equally improved by the retro-cue. Therefore, this finding does not support the view that the sustained focused attention is needed to properly maintain feature bindings in VSTM.

Which Clip? A Prospective Comparative Study of Retention Rates of Endoscopic Clips on Normal Mucosa and Ulcers in a Porcine Model

PubMed Central

Saxena, Payal; Ji-Shin, Eun; Haito-Chavez, Yamile; Valeshabad, Ali K.; Akshintala, Venkata; Aguila, Gerard; Kumbhari, Vivek; Ruben, Dawn S.; Lennon, Anne-Marie; Singh, Vikesh; Canto, Marcia; Kalloo, Anthony; Khashab, Mouen A.

2014-01-01

Background/Aim: There are currently no data on the relative retention rates of the Instinct clip, Resolution clip, and QuickClip2Long. Also, it is unknown whether retention rate differs when clips are applied to ulcerated rather than normal mucosa. The aim of this study is to compare the retention rates of three commonly used endoscopic clips. Materials and Methods: Six pigs underwent upper endoscopy with placement of one of each of the three types of clips on normal mucosa in the gastric body. Three mucosal resections were also performed to create “ulcers”. Each ulcer was closed with placement of one of the three different clips. Repeat endoscopy was performed weekly for up to 4 weeks. Results: Only the Instinct and Resolution clips remained attached for the duration of the study (4 weeks). At each time point, a greater proportion of Instinct clips were retained on normal mucosa, followed by Resolution clips. QuickClip2Long had the lowest retention rate on normal mucosa. Similar retention rates of Instinct clips and Resolution clips were seen on simulated ulcers, although both were superior to QuickClip2Long. However, the difference did not reach statistical significance. All QuickClip2Long clips were dislodged at 4 weeks in both the groups. Conclusions: The Resolution and Instinct clips have comparable retention rates and both appeared to be better than the QuickClip2Long on normal mucosa-simulated ulcers; however this did not reach statistical significance. Both the Resolution clip and the Instinct clip may be preferred in clinical situations when long-term clip attachment is required, including marking of tumors for radiotherapy and anchoring feeding tubes or stents. Either of the currently available clips may be suitable for closure of iatrogenic mucosal defects without features of chronicity. PMID:25434317

Intensive Treatment with Ultrasound Visual Feedback for Speech Sound Errors in Childhood Apraxia

PubMed Central

Preston, Jonathan L.; Leece, Megan C.; Maas, Edwin

2016-01-01

Ultrasound imaging is an adjunct to traditional speech therapy that has shown to be beneficial in the remediation of speech sound errors. Ultrasound biofeedback can be utilized during therapy to provide clients with additional knowledge about their tongue shapes when attempting to produce sounds that are erroneous. The additional feedback may assist children with childhood apraxia of speech (CAS) in stabilizing motor patterns, thereby facilitating more consistent and accurate productions of sounds and syllables. However, due to its specialized nature, ultrasound visual feedback is a technology that is not widely available to clients. Short-term intensive treatment programs are one option that can be utilized to expand access to ultrasound biofeedback. Schema-based motor learning theory suggests that short-term intensive treatment programs (massed practice) may assist children in acquiring more accurate motor patterns. In this case series, three participants ages 10–14 years diagnosed with CAS attended 16 h of speech therapy over a 2-week period to address residual speech sound errors. Two participants had distortions on rhotic sounds, while the third participant demonstrated lateralization of sibilant sounds. During therapy, cues were provided to assist participants in obtaining a tongue shape that facilitated a correct production of the erred sound. Additional practice without ultrasound was also included. Results suggested that all participants showed signs of acquisition of sounds in error. Generalization and retention results were mixed. One participant showed generalization and retention of sounds that were treated; one showed generalization but limited retention; and the third showed no evidence of generalization or retention. Individual characteristics that may facilitate generalization are discussed. Short-term intensive treatment programs using ultrasound biofeedback may result in the acquisition of more accurate motor patterns and improved articulation of sounds previously in error, with varying levels of generalization and retention. PMID:27625603

[Influences of ion-suppressors on retention behaviors of nine food additives in reversed-phase high performance liquid chromatographic separation].

PubMed

Zhao, Yonggang; Chen, Xiaohong; Li, Xiaoping; Yao, Shanshan; Jin, Micong

2011-10-01

The influences of ion-suppressors on retention behaviors of nine food additives, i.e., acesulfame, saccharin, caffeine, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid and neotame in reversed-phase high performance liquid chromatographic (RP-HPLC) separation were investigated. The organic modification effects of acids, i. e. , trifluoroacetic acid (TFA) and buffer salts, i. e. , TFA-ammonium acetate (AmAc) were studied emphatically. The relationships between retention factors of solutes and volume percentages of ion-suppressors in the mobile phase systems of acetonitrile-TFA aqueous solution and acetonitrile-TFA-AmAc aqueous solution were quantitatively established, separately. The separation of nine food additives was completed by a gradient elution with acetonitrile-TFA (0.01%, v/v)-AmAc (2. 5 mmol/L) aqueous solution as the mobile phases. An RP-HPLC method was established for the simultaneous determination of nine food additives in red wine. In the range of 10. 0 - 100. 0 mg/L, nine food additives showed good linearity with the correlation coefficients ( r2 ) larger than 0. 999 1. The limits of detection (LODs) were in the range of 0. 33 - 2. 36 mg/L and the limits of quantification (LOQs) were in the range of 1. 11 - 7. 80 mg/L. The spiked recoveries were between 87. 61% and 108. 4% with the relative standard deviations (RSDs) of 2. 2% -9. 4%. These results are of referential significance for the rapid establishment and accu- rate optimization of RP-HPLC separation for the simultaneous determination of food additives in other foods.

Nitrogen limitation, 15N tracer retention, and growth response in intact and Bromus tectorum-invaded Artemisia tridentata ssp. wyomingensis communities

USGS Publications Warehouse

Witwicki, Dana L.; Doescher, Paul S.; Pyke, David A.; DeCrappeo, Nicole M.; Perakis, Steven S.

2012-01-01

Annual grass invasion into shrub-dominated ecosystems is associated with changes in nutrient cycling that may alter nitrogen (N) limitation and retention. Carbon (C) applications that reduce plant-available N have been suggested to give native perennial vegetation a competitive advantage over exotic annual grasses, but plant community and N retention responses to C addition remain poorly understood in these ecosystems. The main objectives of this study were to (1) evaluate the degree of N limitation of plant biomass in intact versus B. tectorum-invaded sagebrush communities, (2) determine if plant N limitation patterns are reflected in the strength of tracer 15N retention over two growing seasons, and (3) assess if the strength of plant N limitation predicts the efficacy of carbon additions intended to reduce soil N availability and plant growth. Labile C additions reduced biomass of exotic annual species; however, growth of native A. tridentata shrubs also declined. Exotic annual and native perennial plant communities had divergent responses to added N, with B. tectorum displaying greater ability to use added N to rapidly increase aboveground biomass, and native perennials increasing their tissue N concentration but showing little growth response. Few differences in N pools between the annual and native communities were detected. In contrast to expectations, however, more 15N was retained over two growing seasons in the invaded annual grass than in the native shrub community. Our data suggest that N cycling in converted exotic annual grasslands of the northern Intermountain West, USA, may retain N more strongly than previously thought.

Investigation of Single Phase NanoCellulose Transport through Porous Media

NASA Astrophysics Data System (ADS)

Dziuba, Carter Jordan

The application of nanotechnology to the petroleum industry has seen many recent advancements. Nanocellulose is an emerging nanoparticle at the forefront of research. Before nanocellulose can be injected into petroleum reservoirs, further understanding is needed as to the retention mechanisms that occur during nanocellulose transport through porous media. A series of unconsolidated sandpack floods were preformed with nanocellulose and the resulting retention and permeability reduction were measured. The experimental variables include nanocellulose type, sand grain size, flowrate, and salinity. It was found that all types of nanocellulose tested showed significantly different transport properties. Retention and permeability reduction increased as grain size decreased or flowrate decreased. As a general trend, the larger the size of aggregates in bulk solution, the greater the retention and permeability reduction. Salinity was found to be the primary parameter affecting transport. Increased salinity caused additional aggregation which resulted in increased straining and filter cake formation.

The impact of cooking and delivery modes of thymol and carvacrol on retention and bioaccessibility in starchy foods.

PubMed

Aravena, Gabriela; García, Olga; Muñoz, Ociel; Pérez-Correa, José R; Parada, Javier

2016-04-01

Oregano and thyme possess beneficial properties for human health, mainly attributable to monoterpenes such as thymol and carvacrol. The main objective of this research was to assess, on starchy food, the impact of cooking (boiling and baking) and delivery (ground leaves and essential oil) modes on retention and bioaccessibility of thymol and carvacrol. Retention was assessed after cooking, while bioaccessibility was estimated in cooked samples using an in vitro digestion model. Our results indicate that bioaccessibility was weakly dependent on cooking and delivery modes (27-33%). Boil cooking presented 20% more retention than baking for both compounds. When essential oil was added to the food matrix, thymol was retained almost 25% more when compared with ground leaves' addition. Conversely, carvacrol was retained 39% more when ground leaves were added. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of substituted phenylnadimides on processing and properties of PMR polyimide composites

NASA Technical Reports Server (NTRS)

Alston, W. B.; Lauver, R. W.

1985-01-01

Three nitrophenylnadimide cure initiators and two phenylnadimides (without nitros) were evaluated as additives to PMR-15 resins and Celion 6000 graphite fiber composites. The results of a resin screening study eliminated all of the additives except 3-nitrophenylnadimide (NO2PN) for use as a low temperature curing additive for PMR-15. Thus, NO2PN and the two control additives were investigated in PMR-15 formulations from which Celion 6000 graphite fiber/PMR-15 composites were processed both with low temperature (274 C) and normal (316 C) cure cycles. Comparisons of the two processing cycles, the resultant glass transition temperatures (Tg), the ambient, 274 and 316 C composite mechanical properties determined before and after 316 C postcure, the 316 C thermo-oxidative weight losses and the retention of 316 C composite mechanical properties are presented. Empirical correlations of the type and amount of nadimide additives with processing parameters, Tg, composite mechanical properties, composite thermo-oxidative stability and long term retention of 316 C composite mechanical properties are also presented.

Can Colors, Voices, and Images Help Learners Acquire the Grammatical Gender of German Nouns?

ERIC Educational Resources Information Center

Dias de Oliveira Santos, Victor

2015-01-01

Knowledge of lexical items is arguably the most essential aspect of being able to communicate in a foreign language (Richards, 2000). Many studies have examined effective strategies for retaining the meaning of foreign words, but studies investigating the effectiveness of different methods for the retention of essential grammatical features of…

A Framework for Determining the Authenticity of Assessment Tasks: Applied to an Example in Law

ERIC Educational Resources Information Center

Burton, Kelley

2011-01-01

Authentic assessment tasks enhance engagement, retention and the aspirations of students. This paper explores the discipline-generic features of authentic assessment, which reflect what students need to achieve in the real world. Some assessment tasks are more authentic than others and this paper designs a proposed framework supported by the…

Teaching Evolution at A-Level: Is "Intelligent Design" a Scientific Theory That Merits Inclusion in the Biology Syllabus?

ERIC Educational Resources Information Center

Freeland, Peter

2013-01-01

Charles Darwin supposed that evolution involved a process of gradual change, generated randomly, with the selection and retention over many generations of survival-promoting features. Some theists have never accepted this idea. "Intelligent design" is a relatively recent theory, supposedly based on scientific evidence, which attempts to…

Logging in and Dropping out: Exploring Student Non-Completion in Higher Education Using Electronic Footprint Analysis

ERIC Educational Resources Information Center

Buglear, John

2009-01-01

Student retention in higher education might be prioritised by funding authorities and universities but robust measurement of non-completion is elusive. This investigation explores untapped data sources to enrich understanding of non-completion. The analysis features the main undergraduate course in a part of a large UK university with retention…

Evaluating Principal-Preparation Programs Based on Placement Rates: Problems and Prospects for Policymakers

ERIC Educational Resources Information Center

Fuller, Edward J.; Hollingworth, Liz

2016-01-01

Recent calls to hold preparation programs accountable for outcomes have led states to develop and adopt preparation program accountability systems. A primary feature of these systems is a focus on outcomes such as placement rates, retention rates, and graduates' effectiveness in improving K-12 student achievement. Yet, little research has examined…

Seeing Coloured Fruits: Utilisation of the Theory of Adaptive Memory in Teaching Botany

ERIC Educational Resources Information Center

Prokop, Pavol; Fancovicová, Jana

2014-01-01

Plants are characterised by a great diversity of easily observed features such as colours or shape, but children show low interest in learning about them. Here, we integrated modern theory of adaptive memory and evolutionary views of the function of fruit colouration on children's retention of information. Survival-relevant (fruit toxicity) and…

Nuclear reactor support and seismic restraint with in-vessel core retention cooling features

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

Edwards, Tyler A.; Edwards, Michael J.

A nuclear reactor including a lateral seismic restraint with a vertically oriented pin attached to the lower vessel head and a mating pin socket attached to the floor. Thermally insulating materials are disposed alongside the exterior surface of a lower portion of the reactor pressure vessel including at least the lower vessel head.

Contributions of the cerebellum and the motor cortex to acquisition and retention of motor memories

PubMed Central

Herzfeld, David J.; Pastor, Damien; Haith, Adrian M.; Rossetti, Yves; Shadmehr, Reza; O’Shea, Jacinta

2014-01-01

We investigated the contributions of the cerebellum and the motor cortex (M1) to acquisition and retention of human motor memories in a force field reaching task. We found that anodal transcranial direct current stimulation (tDCS) of the cerebellum, a technique that is thought to increase neuronal excitability, increased the ability to learn from error and form an internal model of the field, while cathodal cerebellar stimulation reduced this error-dependent learning. In addition, cathodal cerebellar stimulation disrupted the ability to respond to error within a reaching movement, reducing the gain of the sensory-motor feedback loop. By contrast, anodal M1 stimulation had no significant effects on these variables. During sham stimulation, early in training the acquired motor memory exhibited rapid decay in error-clamp trials. With further training the rate of decay decreased, suggesting that with training the motor memory was transformed from a labile to a more stable state. Surprisingly, neither cerebellar nor M1 stimulation altered these decay patterns. Participants returned 24 hours later and were re-tested in error-clamp trials without stimulation. The cerebellar group that had learned the task with cathodal stimulation exhibited significantly impaired retention, and retention was not improved by M1 anodal stimulation. In summary, non-invasive cerebellar stimulation resulted in polarity-dependent up- or down-regulation of error-dependent motor learning. In addition, cathodal cerebellar stimulation during acquisition impaired the ability to retain the motor memory overnight. Thus, in the force field task we found a critical role for the cerebellum in both formation of motor memory and its retention. PMID:24816533

Difficulties with Pitch Discrimination Influences Pitch Memory Performance: Evidence from Congenital Amusia

PubMed Central

Jiang, Cunmei; Lim, Vanessa K.; Wang, Hang; Hamm, Jeff P.

2013-01-01

Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases. This study examined whether or not the difficulty of pitch discrimination influences pitch retention by testing individuals with congenital amusia. Pitch discrimination difficulty was equated by determining an individual’s threshold with a two down one up staircase procedure and using this to create conditions where two pitches (the standard and the comparison tones) differed by 1x, 2x, and 3x the threshold setting. For comparison with the literature a condition that employed a constant pitch difference of four semitones was also included. The results showed that pitch memory performance improved as the discrimination between the standard and the comparison tones was made easier for both amusic and control groups, and more importantly, that amusics did not show any pitch retention deficits when the discrimination difficulty was equated. In contrast, consistent with previous literature, amusics performed worse than controls when the physical pitch distance was held constant at four semitones. This impaired performance has been interpreted as evidence for pitch memory impairment in the past. However, employing a constant pitch distance always makes the difference closer to the discrimination threshold for the amusic group than for the control group. Therefore, reduced performance in this condition may simply reflect differences in the perceptual difficulty of the discrimination. The findings indicate the importance of equating the discrimination difficulty when investigating memory. PMID:24205375

The grit effect: predicting retention in the military, the workplace, school and marriage

PubMed Central

Eskreis-Winkler, Lauren; Shulman, Elizabeth P.; Beal, Scott A.; Duckworth, Angela L.

2013-01-01

Remaining committed to goals is necessary (albeit not sufficient) to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g., intelligence, physical aptitude, Big Five personality traits, job tenure) and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF) selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time. PMID:24550863

The grit effect: predicting retention in the military, the workplace, school and marriage.

PubMed

Eskreis-Winkler, Lauren; Shulman, Elizabeth P; Beal, Scott A; Duckworth, Angela L

2014-01-01

Remaining committed to goals is necessary (albeit not sufficient) to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g., intelligence, physical aptitude, Big Five personality traits, job tenure) and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF) selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time.

Dietary calcium requirements do not differ between Mexican-American boys and girls.

PubMed

Palacios, Cristina; Martin, Berdine R; McCabe, George P; McCabe, Linda; Peacock, Munro; Weaver, Connie M

2014-08-01

Mexican Americans are an understudied ethnic group for determinants of bone health, although the risk of age-related osteoporosis is high in this rapidly growing sector of the U.S. population. Thus, the objective of the present study was to establish the dietary calcium requirements for bone health in Mexican-American adolescents by measuring calcium retention calculated from balance in response to a range of dietary calcium intakes and to determine predictors of skeletal calcium retention. Adolescents aged 12-15 y were studied twice on paired calcium intakes ranging from 600 to 2300 mg/d using randomized-order, crossover 3-wk balance studies. Skeletal calcium retention was calculated as dietary calcium intake minus calcium excreted in feces and urine over the last 2 wk of balance. A linear model was developed to explain the variation in calcium retention. Boys (n = 20) were taller and had higher lean mass, usual dietary calcium intake, bone mineral content, and serum alkaline phosphatase compared with girls, whereas girls (n = 20) had higher Tanner scores and greater fat mass. Calcium retention increased with calcium intake (P < 0.0001) and did not differ by sex (P = 0.66). In boys and girls considered together, calcium intake explained 33% of the variation in calcium retention. Serum alkaline phosphatase explained an additional 11% of the variation in calcium retention. Other variables measured, including the urine N-telopeptide of type I collagen/creatinine ratio, Tanner score, serum parathyroid hormone and 25-hydroxyvitamin D, weight, height, and body mass index, did not contribute to the variance in calcium retention. In adolescence, calcium retention in both Mexican-American boys and girls was higher than determined previously in adolescent nonHispanic white girls. This trial was registered at clinicaltrials.gov as NCT01277185. © 2014 American Society for Nutrition.

Quantifying Long-Term Retention of Excised Fat Grafts: A Longitudinal, Retrospective Cohort Study of 108 Patients Followed for Up to 8.4 Years.

PubMed

Herly, Mikkel; Ørholt, Mathias; Glovinski, Peter V; Pipper, Christian B; Broholm, Helle; Poulsgaard, Lars; Fugleholm, Kåre; Thomsen, Carsten; Drzewiecki, Krzysztof T

2017-05-01

Predicting the degree of fat graft retention is essential when planning reconstruction or augmentation with free fat grafting. Most surgeons observe volume loss over time after fat grafting; however, the portion lost to resorption after surgery is still poorly defined, and the time to reach steady state is unknown. The authors compiled a retrospective, longitudinal cohort of patients with vestibular schwannoma who had undergone ablative surgery and reconstruction with excised fat between the years 2006 and 2015. Fat volume retention was quantified by computed tomography and magnetic resonance imaging and used to model a graft retention trajectory and determine the volumetric steady state. In addition, the authors evaluated the association between graft retention and secondary characteristics, such as sex and transplant volume. A total of 108 patients were included. The average baseline graft volume was 18.1 ± 4.8 ml. The average time to reach steady state was 806 days after transplantation. By this time, the average fat graft retention was 50.6 percent (95 percent CI, 46.4 to 54.7 percent). No statistically significant association was found between baseline graft volume and retention. Fat graft retention over time was significantly higher in men than in women (57.7 percent versus 44.5 percent; p < 0.001). The authors' data provide evidence that the time to reach fat graft volumetric steady state is considerably longer than previously expected. Fat grafts continue to shrink long after the initial hypoxia-induced tissue necrosis has been cleared, thus indicating that factors other than blood supply may be more influential for fat graft retention. Therapeutic, IV.

Moisture absorption and retention properties, and activity in alleviating skin photodamage of collagen polypeptide from marine fish skin.

PubMed

Hou, Hu; Li, Bafang; Zhang, Zhaohui; Xue, Changhu; Yu, Guangli; Wang, Jingfeng; Bao, Yuming; Bu, Lin; Sun, Jiang; Peng, Zhe; Su, Shiwei

2012-12-01

Collagen polypeptides were prepared from cod skin. Moisture absorption and retention properties of collagen polypeptides were determined at different relative humidities. In addition, the protective effects of collagen polypeptide against UV-induced damage to mouse skin were evaluated. Collagen polypeptides had good moisture absorption and retention properties and could alleviate the damage induced by UV radiation. The action mechanisms of collagen polypeptide mainly involved enhancing immunity, reducing the loss of moisture and lipid, promoting anti-oxidative properties, inhibiting the increase of glycosaminoglycans, repairing the endogenous collagen and elastin protein fibres, and maintaining the ratio of type III to type I collagen. Copyright © 2012 Elsevier Ltd. All rights reserved.

Program design features that can improve participation in health education interventions

PubMed Central

Gucciardi, Enza; Cameron, Jill I; Liao, Chen Di; Palmer, Alison; Stewart, Donna E

2007-01-01

Background Although there have been reported benefits of health education interventions across various health issues, the key to program effectiveness is participation and retention. Unfortunately, not everyone is willing to participate in health interventions upon invitation. In fact, health education interventions are vulnerable to low participation rates. The objective of this study was to identify design features that may increase participation in health education interventions and evaluation surveys, and to maximize recruitment and retention efforts in a general ambulatory population. Methods A cross-sectional questionnaire was administered to 175 individuals in waiting rooms of two hospitals diagnostic centres in Toronto, Canada. Subjects were asked about their willingness to participate, in principle, and the extent of their participation (frequency and duration) in health education interventions under various settings and in intervention evaluation surveys using various survey methods. Results The majority of respondents preferred to participate in one 30–60 minutes education intervention session a year, in hospital either with a group or one-on-one with an educator. Also, the majority of respondents preferred to spend 20–30 minutes each time, completing one to two evaluation surveys per year in hospital or by mail. Conclusion When designing interventions and their evaluation surveys, it is important to consider the preferences for setting, length of participation and survey method of your target population, in order to maximize recruitment and retention efforts. Study respondents preferred short and convenient health education interventions and surveys. Therefore, brevity, convenience and choice appear to be important when designing education interventions and evaluation surveys from the perspective of our target population. PMID:17996089

Biogas from mesophilic anaerobic digestion of cow dung using gelatin as additive

NASA Astrophysics Data System (ADS)

Salam, Bodius; Rahman, Md Mizanur; Sikder, Md Asif R.; Islam, Majedul

2017-06-01

A research work was conducted to investigate the enhanced production ability of biogas from mesophilic anaerobic digestions of cow dung (CD) using gelatin as additive. Five laboratory scale digesters were constructed to digest cow dung, where one set up was used for digestion of cow dung without additive and the other set up were used for digestion with additive. Gelatin additive was added in the slurry of amount 0.29, 0,57, 0.85 and 1.14% (wt.). The digesters were made of glass conical flask of 1-liter capacity each. Cow dung was used 335 gm and water was used 365 gm in each experiment. In the slurry, total solid content was maintained 8% (wt.) for all the observations. The digesters were fed on batch basis. The digesters were operated at ambient temperatures of 26 - 35°C. The total gas yield was obtained about 14.4 L/kg CD for digestion without additive and about 65% more biogas for digestion with 0.29% gelatin additive. The retention time for digestion without additive was 38 days and with additive retention time varied between 24 and 52 days.

Non-labile Soil Nitrogen Retention beneath Three Tree Species in a Tropical Plantation

Treesearch

Jason P. Kaye; Dan Binkley; Xiaoming Zou

2002-01-01

Soil organic matter is the largest sink for N additions to forests. Species composition may affect soilNretention by altering the amount or proportion of added N stored in non-labile organic pools. We measured 15N tracer retention in labile and non-labile pools of surface (0–20 cm) mineral soils, 7 yr after the tracer was applied to a 9 yr-old Puerto Rican tree...

When false recognition is out of control: the case of facial conjunctions.

PubMed

Jones, Todd C; Bartlett, James C

2009-03-01

In three experiments, a dual-process approach to face recognition memory is examined, with a specific focus on the idea that a recollection process can be used to retrieve configural information of a studied face. Subjects could avoid, with confidence, a recognition error to conjunction lure faces (each a reconfiguration of features from separate studied faces) or feature lure faces (each based on a set of old features and a set of new features) by recalling a studied configuration. In Experiment 1, study repetition (one vs. eight presentations) was manipulated, and in Experiments 2 and 3, retention interval over a short number of trials (0-20) was manipulated. Different measures converged on the conclusion that subjects were unable to use a recollection process to retrieve configural information in an effort to temper recognition errors for conjunction or feature lure faces. A single process, familiarity, appears to be the sole process underlying recognition of conjunction and feature faces, and familiarity contributes, perhaps in whole, to discrimination of old from conjunction faces.

Preparation of titanium phosphates with additives in hydrothermal process and their powder properties for cosmetics.

PubMed

Onoda, Hiroaki; Yamaguchi, Taisuke

2013-04-01

In this study, titanium phosphates were prepared from titanium chloride and phosphoric acid, sodium pyrophosphate and sodium triphosphate solutions with water retention compounds in hydrothermal process as a novel white pigment for cosmetics. Their chemical composition, powder properties, photo catalytic activity, water retention and smoothness were studied. The addition of glycerin in the preparation from sodium pyrophosphate has the useful method to obtain homogenized spherical particles of titanium phosphate pigments for the cosmetics. These titanium phosphates had less photo catalytic activity to protect the sebum on the skin. © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Attaching transmitters to waterbirds using one versus two subcutaneous anchors: Retention and survival trade-offs

USGS Publications Warehouse

Lewis, Tyler; Esler, Daniel N.; Uher-Koch, Brian D.; Dickson, Rian D.; Anderson, Eric M.; Evenson, Joseph R.; Hupp, Jerry W.; Flint, Paul L.

2017-01-01

A major challenge of wildlife telemetry is choosing an attachment technique that maximizes transmitter retention while minimizing negative side effects. For waterbirds, attachment of transmitters with subcutaneous anchors has been an effective and well-established technique, having been used on >40 species. This method was recently modified to include a second subcutaneous anchor, presumably increasing transmitter retention beyond that of single-anchor attachments. This putative benefit may be offset, however, by increased health risks related to additional incisions and subcutaneous protrusions. To test this potential trade-off, we attached radiotransmitters to molting and wintering surf (Melanitta perspicillata) and white-winged scoters (M. fusca) during 2008 and 2009 in Washington State and southeast Alaska, USA, using single- (121 scoters) and double-anchor (128 scoters) attachment techniques. We estimated daily probabilities of survival and radio retention for each group, this being apparent retention for wintering scoters because we could not differentiate shed transmitters from flighted emigration. For scoters during the flightless remigial molt, we found that addition of a second anchor increased cumulative retention probability (±SE) over a 49-day period from 0.69 ± 0.11 for single-anchor to 0.88 ± 0.07 for double-anchor attachments, while having no effect on survival. However, during winter, scoters with double-anchor attachments experienced no improvement in apparent retention, while having significantly lower survival during their first 14 days following transmitter attachment; of 15 mortalities during this period, 11 had 2 subcutaneous anchors. From day 15 onward, winter survival rates were nearly identical for single- versus double-anchor attachments, indicating that adverse effects of subcutaneous anchors were mainly limited to the 14-day postattachment period. Overall, given that the survival cost of adding a second subcutaneous anchor was substantial for wintering scoters—decreasing 14-day survival by 12% for adults and 23% for juveniles—we recommend that researchers opt for single-anchor attachments under most circumstances, especially during winter when birds may be energetically challenged. 

Best practice guidance for the use of strategies to improve retention in randomized trials developed from two consensus workshops

PubMed Central

Brueton, Valerie; Stenning, Sally P.; Stevenson, Fiona; Tierney, Jayne; Rait, Greta

2017-01-01

Objectives To develop best practice guidance for the use of retention strategies in randomized clinical trials (RCTs). Study Design and Setting Consensus development workshops conducted at two UK Clinical Trials Units. Sixty-six statisticians, clinicians, RCT coordinators, research scientists, research assistants, and data managers associated with RCTs participated. The consensus development workshops were based on the consensus development conference method used to develop best practice for treatment of medical conditions. Workshops commenced with a presentation of the evidence for incentives, communication, questionnaire format, behavioral, case management, and methodological retention strategies identified by a Cochrane review and associated qualitative study. Three simultaneous group discussions followed focused on (1) how convinced the workshop participants were by the evidence for retention strategies, (2) barriers to the use of effective retention strategies, (3) types of RCT follow-up that retention strategies could be used for, and (4) strategies for future research. Summaries of each group discussion were fed back to the workshop. Coded content for both workshops was compared for agreement and disagreement. Agreed consensus on best practice guidance for retention was identified. Results Workshop participants agreed best practice guidance for the use of small financial incentives to improve response to postal questionnaires in RCTs. Use of second-class post was thought to be adequate for postal communication with RCT participants. The most relevant validated questionnaire was considered best practice for collecting RCT data. Barriers identified for the use of effective retention strategies were: the small improvements seen in questionnaire response for the addition of monetary incentives, and perceptions among trialists that some communication strategies are outdated. Furthermore, there was resistance to change existing retention practices thought to be effective. Face-to-face and electronic follow-up technologies were identified as retention strategies for further research. Conclusions We developed best practice guidance for the use of retention strategies in RCTs and identified potential barriers to the use of effective strategies. The extent of agreement on best practice is limited by the variability in the currently available evidence. This guidance will need updating as new retention strategies are developed and evaluated. PMID:28546093

Best practice guidance for the use of strategies to improve retention in randomized trials developed from two consensus workshops.

PubMed

Brueton, Valerie; Stenning, Sally P; Stevenson, Fiona; Tierney, Jayne; Rait, Greta

2017-08-01

To develop best practice guidance for the use of retention strategies in randomized clinical trials (RCTs). Consensus development workshops conducted at two UK Clinical Trials Units. Sixty-six statisticians, clinicians, RCT coordinators, research scientists, research assistants, and data managers associated with RCTs participated. The consensus development workshops were based on the consensus development conference method used to develop best practice for treatment of medical conditions. Workshops commenced with a presentation of the evidence for incentives, communication, questionnaire format, behavioral, case management, and methodological retention strategies identified by a Cochrane review and associated qualitative study. Three simultaneous group discussions followed focused on (1) how convinced the workshop participants were by the evidence for retention strategies, (2) barriers to the use of effective retention strategies, (3) types of RCT follow-up that retention strategies could be used for, and (4) strategies for future research. Summaries of each group discussion were fed back to the workshop. Coded content for both workshops was compared for agreement and disagreement. Agreed consensus on best practice guidance for retention was identified. Workshop participants agreed best practice guidance for the use of small financial incentives to improve response to postal questionnaires in RCTs. Use of second-class post was thought to be adequate for postal communication with RCT participants. The most relevant validated questionnaire was considered best practice for collecting RCT data. Barriers identified for the use of effective retention strategies were: the small improvements seen in questionnaire response for the addition of monetary incentives, and perceptions among trialists that some communication strategies are outdated. Furthermore, there was resistance to change existing retention practices thought to be effective. Face-to-face and electronic follow-up technologies were identified as retention strategies for further research. We developed best practice guidance for the use of retention strategies in RCTs and identified potential barriers to the use of effective strategies. The extent of agreement on best practice is limited by the variability in the currently available evidence. This guidance will need updating as new retention strategies are developed and evaluated. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Development and implementation of a laboratory spray device and rainfall simulator for retention research using small amounts of agroformulations.

PubMed

Zwertvaegher, Ingrid Ka; Van Daele, Inge; Verheesen, Peter; Peferoen, Marnix; Nuyttens, David

2017-01-01

Rainfall greatly affects the retention of foliar-applied agroformulations. Improving their resistance to wash-off is therefore of great importance in spray applications. When developing such formulations, small-scale laboratory assays are generally required. A set-up for retention studies using only small amounts of agroformulations (<0.5 L) was developed. The set-up consists of a spray device and a rainfall simulator. The effect of rain quantity (1, 3, 6 mm) on the spray retention of agroformulations was evaluated using this set-up. The data showed that uniform and repeatable spraying was achieved with the small-scale spray device (coefficient of variation 23.4%) on potato pot plants (Solanum tuberosum L.). Rain quantity significantly affected the spray retention. Approximately 40% of the initial deposition was lost after 1 mm of rain at an intensity of 25 mm h -1 . Additional losses decreased with increasing volumes of rain (65 and 80% loss after 3 and 6 mm of rain respectively). Future studies could implement the set-up to evaluate the effect of different rainfall characteristics and formulations on spray retention in order to improve the rainfastness of agroformulations. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

The Cost and Threshold Analysis of Retention in Care (RiC): A Multi-Site National HIV Care Program.

PubMed

Maulsby, Catherine; Jain, Kriti M; Weir, Brian W; Enobun, Blessing; Riordan, Maura; Charles, Vignetta E; Holtgrave, David R

2017-03-01

Persons diagnosed with HIV but not retained in HIV medical care accounted for the majority of HIV transmissions in 2009 in the United States (US). There is an urgent need to implement and disseminate HIV retention in care programs; however little is known about the costs associated with implementing retention in care programs. We assessed the costs and cost-saving thresholds for seven Retention in Care (RiC) programs implemented in the US using standard methods recommended by the US Panel on Cost-effectiveness in Health and Medicine. Data were gathered from accounting and program implementation records, entered into a standardized RiC economic analysis spreadsheet, and standardized to a 12 month time frame. Total program costs for from the societal perspective ranged from $47,919 to $423,913 per year or $146 to $2,752 per participant. Cost-saving thresholds ranged from 0.13 HIV transmissions averted to 1.18 HIV transmission averted per year. We estimated that these cost-saving thresholds could be achieved through 1 to 16 additional person-years of viral suppression. Across a range of program models, retention in care interventions had highly achievable cost-saving thresholds, suggesting that retention in care programs are a judicious use of resources.

Specialized moisture retention eyewear for evaporative dry eye.

PubMed

Waduthantri, Samanthila; Tan, Chien Hua; Fong, Yee Wei; Tong, Louis

2015-05-01

To evaluate the suitablity of commercially available moisture retention eyewear for treating evaporative dry eye. Eleven patients with evaporative dry eyes were prescibed moisture retention eyewear for 3 months in addition to regular lubricant eye drops. Frequency and severity of dry eye symptoms, corneal fluorescein staining and tear break up time (TBUT) were evaluated at baseline and 3-month post-treatment. Main outcome measure was global symptom score (based on severity and frequency of dry eye symptoms on a visual analog scale) and secondary outcomes were changes in sectoral corneal fluorescein staining and tear break up time (TBUT) from pre-treatment level. There was a significant improvement in dry eye symptoms after using moisture retention eyewear for 3 months (p < 0.05). Corneal fluorescein staining in all five zones of the cornea in both eyes improved significantly (p < 0.05). There was no significant improvement in TBUT. Patients used ocular lubricants less frequently (p < 0.05) compared to the commencement of the study. Patients found moisture retention eyewear to be useful in relieving dry eye symptoms in windy, air-conditioned environments or when doing vision-related daily tasks. This study shows that moisture retention eyewear might be a valuable adjunct in management of evaporative dry eye and this new design of commercially available eyewear could have a good acceptability rate.

NASA's Potential Contributions for Remediation of Retention Ponds Using Solar Ultraviolet Radiation and Photocatalysis

NASA Technical Reports Server (NTRS)

Underwood, Lauren W.; Ryan, Robert E.

2007-01-01

This Candidate Solution uses NASA Earth science research on atmospheric ozone and aerosols data (1) to help improve the prediction capabilities of water runoff models that are used to estimate runoff pollution from retention ponds, and (2) to understand the pollutant removal contribution and potential of photocatalytically coated materials that could be used in these ponds. Models (the EPA's SWMM and the USGS SLAMM) exist that estimate the release of pollutants into the environment from storm-water-related retention pond runoff. UV irradiance data acquired from the satellite mission Aura and from the OMI Surface UV algorithm will be incorporated into these models to enhance their capabilities, not only by increasing the general understanding of retention pond function (both the efficacy and efficiency) but additionally by adding photocatalytic materials to these retention ponds, augmenting their performance. State and local officials who run pollution protection programs could then develop and implement photocatalytic technologies for water pollution control in retention ponds and use them in conjunction with existing runoff models. More effective decisions about water pollution protection programs could be made, the persistence and toxicity of waste generated could be minimized, and subsequently our natural water resources would be improved. This Candidate Solution is in alignment with the Water Management and Public Health National Applications.

Application of the artificial neural network in quantitative structure-gradient elution retention relationship of phenylthiocarbamyl amino acids derivatives.

PubMed

Tham, S Y; Agatonovic-Kustrin, S

2002-05-15

Quantitative structure-retention relationship(QSRR) method was used to model reversed-phase high-performance liquid chromatography (RP-HPLC) separation of 18 selected amino acids. Retention data for phenylthiocarbamyl (PTC) amino acids derivatives were obtained using gradient elution on ODS column with mobile phase of varying acetonitrile, acetate buffer and containing 0.5 ml/l of triethylamine (TEA). Molecular structure of each amino acid was encoded with 36 calculated molecular descriptors. The correlation between the molecular descriptors and the retention time of the compounds in the calibration set was established using the genetic neural network method. A genetic algorithm (GA) was used to select important molecular descriptors and supervised artificial neural network (ANN) was used to correlate mobile phase composition and selected descriptors with the experimentally derived retention times. Retention time values were used as the network's output and calculated molecular descriptors and mobile phase composition as the inputs. The best model with five input descriptors was chosen, and the significance of the selected descriptors for amino acid separation was examined. Results confirmed the dominant role of the organic modifier in such chromatographic systems in addition to lipophilicity (log P) and molecular size and shape (topological indices) of investigated solutes.

Central ghrelin increases anxiety in the Open Field test and impairs retention memory in a passive avoidance task in neonatal chicks.

PubMed

Carvajal, Pedro; Carlini, Valeria P; Schiöth, Helgi B; de Barioglio, Susana R; Salvatierra, Nancy A

2009-05-01

Ghrelin (Grh) is an endogenous ligand for the growth hormone secretagogue receptor. Although Ghr stimulates feeding in rats, it inhibits feeding in neonatal chicks. However, little is known about other central behavioral effects of Ghr. Therefore, we investigated the Ghr effects, injected intracerebroventricularly, on anxiety and memory retention of neonatal chicks in an Open Field test and in a one-trial passive avoidance task, respectively. In the Open Field test, the administration of Ghr in a dose-dependent manner increased the latency to ambulate but decreased ambulation activity, indicating an anxiogenic effect. Furthermore, chicks trained on a passive avoidance task and injected with a dose of 30pmol of Ghr immediately after training showed an impairment of memory retention. However, there were no significant effects on the number of pecks during the pretraining, training, retention and discrimination. In addition, different doses of Ghr produced an inhibition in food intake at different times after injection. Our results indicate that Ghr induces anxiogenesis in chicks. Moreover, we have shown for the first time that Ghr can decrease memory retention in a non-mammalian species, suggesting that Ghr may play an important role in the processes of memory retention in birds.

Alternative splicing mechanisms orchestrating post-transcriptional gene expression: intron retention and the intron-rich genome of apicomplexan parasites.

PubMed

Lunghi, Matteo; Spano, Furio; Magini, Alessandro; Emiliani, Carla; Carruthers, Vern B; Di Cristina, Manlio

2016-02-01

Apicomplexan parasites including Toxoplasma gondii and Plasmodium species have complex life cycles that include multiple hosts and differentiation through several morphologically distinct stages requiring marked changes in gene expression. This review highlights emerging evidence implicating regulation of mRNA splicing as a mechanism to prime these parasites for rapid gene expression upon differentiation. We summarize the most important insights in alternative splicing including its role in regulating gene expression by decreasing mRNA abundance via 'Regulated Unproductive Splicing and Translation'. As a related but less well-understood mechanism, we discuss also our recent work suggesting a role for intron retention for precluding translation of stage specific isoforms of T. gondii glycolytic enzymes. We additionally provide new evidence that intron retention might be a widespread mechanism during parasite differentiation. Supporting this notion, recent genome-wide analysis of Toxoplasma and Plasmodium suggests intron retention is more pervasive than heretofore thought. These findings parallel recent emergence of intron retention being more prevalent in mammals than previously believed, thereby adding to the established roles in plants, fungi and unicellular eukaryotes. Deeper mechanistic studies of intron retention will provide important insight into its role in regulating gene expression in apicomplexan parasites and more general in eukaryotic organisms.

Comparison of isocratic retention models for hydrophilic interaction liquid chromatographic separation of native and fluorescently labeled oligosaccharides.

PubMed

Česla, Petr; Vaňková, Nikola; Křenková, Jana; Fischer, Jan

2016-03-18

In this work, we have investigated retention of maltooligosaccharides and their fluorescent derivatives in hydrophilic interaction liquid chromatography using four different stationary phases. The non-derivatized maltooligosaccharides (maltose to maltoheptaose) and their derivatives with 2-aminobenzoic acid, 2-aminobenzamide, 2-aminopyridine and 8-aminonaphthalene-1,3,6-trisulfonic acid were analyzed on silica gel, aminopropyl silica, amide (carbamoyl-bonded silica) and ZIC-HILIC zwitterionic sulfobetain bonded phase. The partitioning of the analytes between the bulk mobile phase and adsorbed water-rich layer, polar and ionic interactions of analytes with stationary phase have been evaluated and compared. The effects of the mobile phase additives (0.1% (v/v) of acetic acid and ammonium acetate in concentration range 5-30 mmol L(-1)) on retention were described. The suitability of different models for prediction of retention was tested including linear solvent strength model, quadratic model, mixed-mode model, and empirical Neue-Kuss model. The mixed-mode model was extended to the parameter describing the contribution of monomeric glucose unit to the retention of non-derivatized and derivatized maltooligosaccharides, which was used for evaluation of contribution of both, oligosaccharide backbone and end-group to retention. Copyright © 2016 Elsevier B.V. All rights reserved.

New applications of X-ray tomography in pyrolysis of biomass: Biochar imaging

DOE PAGES

Jones, Keith; Ramakrishnan, Girish; Uchimiya, Minori; ...

2015-01-30

We report on the first ever use of non-destructive micrometer-scale synchrotron-computed microtomography (CMT) for biochar material characterization as a function of pyrolysis temperature. This innovative approach demonstrated an increase in micron-sized marcropore fraction of the Cotton Hull (CH) sample, resulting in up to 29% sample porosity. We have also found that initial porosity development occurred at low temperatures (below 350°C) of pyrolysis, consistent with chemical composition of CH. This innovative technique can be highly complementary to traditional BET measurements, considering that Barrett–Joyner–Halenda (BJH) analysis of pore size distribution cannot detect these macropores. Such information can be of substantial relevance tomore » environmental applications, given that water retention by biochars added to soils is controlled by macropore characteristic among the other factors. In addition, complementing our data with SEM, EDX, and XRF characterization techniques allowed us to develop a better understanding of evolution of biochar properties during its production, such presence of metals and initial morphological features of biochar before pyrolysis. These results have significant implications for using biochar as a soil additive and for clarifying the mechanisms of biofuel production by pyrolysis.« less

New applications of X-ray tomography in pyrolysis of biomass: Biochar imaging

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

Jones, Keith; Ramakrishnan, Girish; Uchimiya, Minori

We report on the first ever use of non-destructive micrometer-scale synchrotron-computed microtomography (CMT) for biochar material characterization as a function of pyrolysis temperature. This innovative approach demonstrated an increase in micron-sized marcropore fraction of the Cotton Hull (CH) sample, resulting in up to 29% sample porosity. We have also found that initial porosity development occurred at low temperatures (below 350°C) of pyrolysis, consistent with chemical composition of CH. This innovative technique can be highly complementary to traditional BET measurements, considering that Barrett–Joyner–Halenda (BJH) analysis of pore size distribution cannot detect these macropores. Such information can be of substantial relevance tomore » environmental applications, given that water retention by biochars added to soils is controlled by macropore characteristic among the other factors. In addition, complementing our data with SEM, EDX, and XRF characterization techniques allowed us to develop a better understanding of evolution of biochar properties during its production, such presence of metals and initial morphological features of biochar before pyrolysis. These results have significant implications for using biochar as a soil additive and for clarifying the mechanisms of biofuel production by pyrolysis.« less

Data processing, multi-omic pathway mapping, and metabolite activity analysis using XCMS Online

PubMed Central

Forsberg, Erica M; Huan, Tao; Rinehart, Duane; Benton, H Paul; Warth, Benedikt; Hilmers, Brian; Siuzdak, Gary

2018-01-01

Systems biology is the study of complex living organisms, and as such, analysis on a systems-wide scale involves the collection of information-dense data sets that are representative of an entire phenotype. To uncover dynamic biological mechanisms, bioinformatics tools have become essential to facilitating data interpretation in large-scale analyses. Global metabolomics is one such method for performing systems biology, as metabolites represent the downstream functional products of ongoing biological processes. We have developed XCMS Online, a platform that enables online metabolomics data processing and interpretation. A systems biology workflow recently implemented within XCMS Online enables rapid metabolic pathway mapping using raw metabolomics data for investigating dysregulated metabolic processes. In addition, this platform supports integration of multi-omic (such as genomic and proteomic) data to garner further systems-wide mechanistic insight. Here, we provide an in-depth procedure showing how to effectively navigate and use the systems biology workflow within XCMS Online without a priori knowledge of the platform, including uploading liquid chromatography (LCLC)–mass spectrometry (MS) data from metabolite-extracted biological samples, defining the job parameters to identify features, correcting for retention time deviations, conducting statistical analysis of features between sample classes and performing predictive metabolic pathway analysis. Additional multi-omics data can be uploaded and overlaid with previously identified pathways to enhance systems-wide analysis of the observed dysregulations. We also describe unique visualization tools to assist in elucidation of statistically significant dysregulated metabolic pathways. Parameter input takes 5–10 min, depending on user experience; data processing typically takes 1–3 h, and data analysis takes ~30 min. PMID:29494574

Defining the property space for chromatographic ligands from a homologous series of mixed-mode ligands.

PubMed

Woo, James A; Chen, Hong; Snyder, Mark A; Chai, Yiming; Frost, Russell G; Cramer, Steven M

2015-08-14

A homologous ligand library based on the commercially-available Nuvia cPrime ligand was generated to systematically explore various features of a multimodal cation-exchange ligand and to identify structural variants that had significantly altered chromatographic selectivity. Substitution of the polar amide bond with more hydrophobic chemistries was found to enhance retention while remaining hydrophobically-selective for aromatic residues. In contrast, increasing the solvent exposure of the aromatic ring was observed to strengthen the ligand affinity for both types of hydrophobic residues. An optimal linker length between the charged and hydrophobic moieties was also observed to enhance retention, balancing the steric accessibility of the hydrophobic moiety with its ability to interact independently of the charged group. The weak pKa of the carboxylate charge group was found to have a notable impact on protein retention on Nuvia cPrime at lower pH, increasing hydrophobic interactions with the protein. Substituting the charged group with a sulfonic acid allowed this strong MM ligand to retain its electrostatic-dominant character in this lower pH range. pH gradient experiments were also carried out to further elucidate this pH dependent behavior. A single QSAR model was generated using this accumulated experimental data to predict protein retention across a range of multimodal and ion exchange systems. This model could correctly predict the retention of proteins on resins that were not included in the original model and could prove quite powerful as an in silico approach toward designing more effective and differentiated multimodal ligands. Copyright © 2015. Published by Elsevier B.V.

Revisited reaction-diffusion model of thermal desorption spectroscopy experiments on hydrogen retention in material

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

Guterl, Jerome, E-mail: jguterl@ucsd.edu; Smirnov, R. D.; Krasheninnikov, S. I.

Desorption phase of thermal desorption spectroscopy (TDS) experiments performed on tungsten samples exposed to flux of hydrogen isotopes in fusion relevant conditions is analyzed using a reaction-diffusion model describing hydrogen retention in material bulk. Two regimes of hydrogen desorption are identified depending on whether hydrogen trapping rate is faster than hydrogen diffusion rate in material during TDS experiments. In both regimes, a majority of hydrogen released from material defects is immediately outgassed instead of diffusing deeply in material bulk when the evolution of hydrogen concentration in material is quasi-static, which is the case during TDS experiments performed with tungsten samplesmore » exposed to flux of hydrogen isotopes in fusion related conditions. In this context, analytical expressions of the hydrogen outgassing flux as a function of the material temperature are obtained with sufficient accuracy to describe main features of thermal desorption spectra (TDSP). These expressions are then used to highlight how characteristic temperatures of TDSP depend on hydrogen retention parameters, such as trap concentration or activation energy of detrapping processes. The use of Arrhenius plots to characterize retention processes is then revisited when hydrogen trapping takes place during TDS experiments. Retention processes are also characterized using the shape of desorption peaks in TDSP, and it is shown that diffusion of hydrogen in material during TDS experiment can induce long desorption tails visible aside desorption peaks at high temperature in TDSP. These desorption tails can be used to estimate activation energy of diffusion of hydrogen in material.« less

The Surface Composition of Large Kuiper Belt Object 2007 OR10

NASA Astrophysics Data System (ADS)

Brown, M. E.; Burgasser, A. J.; Fraser, W. C.

2011-09-01

We present photometry and spectra of the large Kuiper belt object 2007 OR10. The data show significant near-infrared absorption features due to water ice. While most objects in the Kuiper belt with water ice absorption this prominent have the optically neutral colors of water ice, 2007 OR10 is among the reddest Kuiper belt objects known. One other large Kuiper belt object—Quaoar—has similar red coloring and water ice absorption, and it is hypothesized that the red coloration of this object is due to irradiation of the small amounts of methane able to be retained on Quaoar. 2007 OR10, though warmer than Quaoar, is in a similar volatile retention regime because it is sufficiently larger that its stronger gravity can still retain methane. We propose, therefore, that the red coloration on 2007 OR10 is also caused by the retention of small amounts of methane. Positive detection of methane on 2007 OR10 will require spectra with higher signal to noise. Models for volatile retention on Kuiper belt objects appear to continue to do an excellent job reproducing all of the available observations.

The impact of humanitarian context conditions and individual characteristics on aid worker retention.

PubMed

Korff, Valeska P; Balbo, Nicoletta; Mills, Melinda; Heyse, Liesbet; Wittek, Rafael

2015-07-01

High employee turnover rates constitute a major challenge to effective aid provision. This study examines how features of humanitarian work and aid workers' individual characteristics affect retention within one humanitarian organisation, Médecins Sans Frontières (MSF) Holland. The study extends existing research by providing new theoretical explanations of employment opportunities and constraints and by engaging in the first large-scale quantitative analysis of aid worker retention. Using a database of field staff (N=1,955), a logistic regression is performed of the likelihood of reenlistment after a first mission. The findings demonstrate that only 40 per cent of employees reenlist for a second mission with MSF Holland, and that workplace location and security situation, age, and gender have no significant effect. Individuals are less likely to reenlist if they returned early from the first mission for a personal reason, are in a relationship, are medical doctors, or if they come from highly developed countries. The paper reflects on the findings in the light of policy. © 2015 The Author(s). Disasters © Overseas Development Institute, 2015.

Relapse of incisor crowding: a visit to the Prince of Salina.

PubMed

López-Areal, Luis; Gandía, Jose-Luis

2013-03-01

The management of the retention period after comprehensive orthodontic treatment is of great importance, as a primary goal of clinician. Considerable controversy still surrounds the problem of stability after the retention period. Many studies analyze factors associated to the presence of crowding or incisor irregularity and find predictive features on its relapse. Most studies have reported little o no correlation between the treatment changes in the biological parameters - clinical, biometric (irregularity index, intermolar width, intercanine width, arch length, overjet, overbite), or cephalometric variables- that ocurred and the posttretament and postretention changes that may predict their future development. This article provides a bibliographical overview on the relapse of dental alignment in treated cases. In a brief historical introduction, the first studies on the long-term stability of orthodontic results are analysed. The article then goes on to assess studies that focus attention on anteroinferior alignment before finally studying relapse of upper crowding. It concludes by making some final comments in the light of the bibliography provided and the differents schools regarding retention needs and methods.

Towards high through-put biological treatment of municipal wastewater and enhanced phosphorus recovery using a hybrid microfiltration-forward osmosis membrane bioreactor with hydraulic retention time in sub-hour level.

PubMed

Qiu, Guanglei; Zhang, Sui; Srinivasa Raghavan, Divya Shankari; Das, Subhabrata; Ting, Yen-Peng

2016-11-01

This work uncovers an important feature of the forward osmosis membrane bioreactor (FOMBR) process: the decoupling of contaminants retention time (CRT) and hydraulic retention time (HRT). Based on this concept, the capability of the hybrid microfiltration-forward osmosis membrane bioreactor (MF-FOMBR) in achieving high through-put treatment of municipal wastewater with enhanced phosphorus recovery was explored. High removal of TOC and NH4(+)-N (90% and 99%, respectively) was achieved with HRTs down to 47min, with the treatment capacity increased by an order of magnitude. Reduced HRT did not affect phosphorus removal and recovery. As a result, the phosphorus recovery capacity was also increased by the same order. Reduced HRT resulted in increased system loading rates and thus elevated concentrations of mixed liquor suspended solids and increased membrane fouling. 454-pyrosequecing suggested the thriving of Bacteroidetes and Proteobacteria (especially Sphingobacteriales Flavobacteriales and Thiothrix members), as well as the community succession and dynamics of ammonium oxidizing and nitrite oxidizing bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

Double-plasma enhanced carbon shield for spatial/interfacial controlled electrodes in lithium ion batteries via micro-sized silicon from wafer waste

NASA Astrophysics Data System (ADS)

Chen, Bing-Hong; Chuang, Shang-I.; Duh, Jenq-Gong

2016-11-01

Using spatial and interfacial control, the micro-sized silicon waste from wafer slurry could greatly increase its retention potential as a green resource for silicon-based anode in lithium ion batteries. Through step by step spatial and interfacial control for electrode, the cyclability of recycled waste gains potential performance from its original poor retention property. In the stages of spatial control, the electrode stabilizers of active, inactive and conductive additives were mixed into slurries for maintaining architecture and conductivity of electrode. In addition, a fusion electrode modification of interfacial control combines electrolyte additive, technique of double-plasma enhanced carbon shield (D-PECS) to convert the chemical bond states and to alter the formation of solid electrolyte interphases (SEIs) in the first cycle. The depth profiles of chemical composition from external into internal electrode illustrate that the fusion electrode modification not only forms a boundary to balance the interface between internal and external electrodes but also stabilizes the SEIs formation and soothe the expansion of micro-sized electrode. Through these effect approaches, the performance of micro-sized Si waste electrode can be boosted from its serious capacity degradation to potential retention (200 cycles, 1100 mAh/g) and better meet the requirements for facile and cost-effective in industrial production.

Acidogenesis and Two-Phase Codigestion of Fats, Oils, and Greases and Municipal Biosolids.

PubMed

Varin, Ross; Novak, John; Bott, Charles

2016-11-01

  Acidogenic codigestion of fats, oils, and greases (FOG) was studied using suspended growth sludge digesters operated as batch fed reactors that were fed twice daily. The digesters were maintained at a 2-day retention time and at 37 °C to mimic the acid phase of an acid-gas digestion system. As FOG loading rates increased, volatile fatty acid (VFA) production was found to increase, although the percentage of VFA production compared to theoretical values decreased exponentially to just 20% at the highest loading rates. FOG matter was found to have accumulated in the reactor vessel in semi-solid balls that floated near the liquid surface. Two-phase codigestion of FOG was studied at 37 °C using Continuously Stirred Tank Reactors (CSTRs) as acid phase digesters (APD) operated with 2-day retention times, followed by gas phase digesters (GPD) with 15-day retention times. The two-phase systems were compared by FOG addition to the APD versus GPD. FOG addition to the APD resulted in 88% destruction of LCFAs, whereas FOG addition to the GPD resulted in 95% destruction of LCFAs. Accumulated LCFAs were found in the APD receiving FOG and were primarily composed palmitic acid (16:0), followed by oleic acid (18:1) and stearic acid (18:0).

Non-labile Soil 15Nitrogen Retention beneath Three Tree Species in a Tropical Plantation

Treesearch

Jason P. Kaye; Dan Binkley; Xiaoming Zou

2002-01-01

Soil organic matter is the largest sink for N additions to forests.Species composition may affect soilNretention by altering the amount or proportion of added N stored in non-labile organic pools. We measured 15N tracer retention in labile and non-labile pools of surface (0–20 cm) mineral soils, 7 yr after the tracer was applied to a 9 yr-old Puerto Rican tree...

Layered oxide, graphite and silicon-graphite electrodes for Lithium-ion cells: Effect of electrolyte composition and cycling windows

DOE PAGES

Klett, Matilda; Gilbert, James A.; Pupek, Krzysztof Z.; ...

2016-10-14

The electrochemical performance of cells with a Li 1.03(Ni 0.5Co 0.2Mn 0.3) 0.97O 2 (NCM523) positive electrode and a blended silicon-graphite (Si-Gr) negative electrode are investigated using various electrolyte compositions and voltage cycling windows. Voltage profiles of the blended Si-Gr electrode show a superposition of graphite potential plateaus on a sloped Si profile with a large potential hysteresis. The effect of this hysteresis is seen in the cell impedance versus voltage data, which are distinctly different for the charge and discharge cycles. We confirm that the addition of compounds, such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC) to themore » baseline 1.2 M LiPF 6 in ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3:7 w/w) electrolyte, improves cell capacity retention with higher retention seen at higher additive contents. We show that reducing the lower cutoff voltage (LCV) of full cells to 2.5 V increases the Si-Gr electrode potential to 1.12 V vs. Li/Li +; this relatively-high delithiation potential correlates with the lower capacity retention displayed by the cell. Hence, we show that raising the upper cutoff voltage (UCV) can increase cell energy density without significantly altering capacity retention over 100 charge discharge cycles.« less

Layered oxide, graphite and silicon-graphite electrodes for Lithium-ion cells: Effect of electrolyte composition and cycling windows

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

Klett, Matilda; Gilbert, James A.; Pupek, Krzysztof Z.

The electrochemical performance of cells with a Li 1.03(Ni 0.5Co 0.2Mn 0.3) 0.97O 2 (NCM523) positive electrode and a blended silicon-graphite (Si-Gr) negative electrode are investigated using various electrolyte compositions and voltage cycling windows. Voltage profiles of the blended Si-Gr electrode show a superposition of graphite potential plateaus on a sloped Si profile with a large potential hysteresis. The effect of this hysteresis is seen in the cell impedance versus voltage data, which are distinctly different for the charge and discharge cycles. We confirm that the addition of compounds, such as vinylene carbonate (VC) and fluoroethylene carbonate (FEC) to themore » baseline 1.2 M LiPF 6 in ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3:7 w/w) electrolyte, improves cell capacity retention with higher retention seen at higher additive contents. We show that reducing the lower cutoff voltage (LCV) of full cells to 2.5 V increases the Si-Gr electrode potential to 1.12 V vs. Li/Li +; this relatively-high delithiation potential correlates with the lower capacity retention displayed by the cell. Hence, we show that raising the upper cutoff voltage (UCV) can increase cell energy density without significantly altering capacity retention over 100 charge discharge cycles.« less

Predictors of 4-year retention among African American and white community-dwelling participants in the UAB study of aging.

PubMed

Allman, Richard M; Sawyer, Patricia; Crowther, Martha; Strothers, Harry S; Turner, Timothy; Fouad, Mona N

2011-06-01

To identify racial/ethnic differences in retention of older adults at 3 levels of participation in a prospective observational study: telephone, in-home assessments, and home visits followed by blood draws. A prospective study of 1,000 community-dwelling Medicare beneficiaries aged 65 years and older included a baseline in-home assessment and telephone follow-up calls at 6-month intervals; at 4 years, participants were asked to complete an additional in-home assessment and have blood drawn. After 4 years, 21.7% died and 0.7% withdrew, leaving 776 participants eligible for follow-up (49% African American; 46% male; 51% rural). Retention for telephone follow-up was 94.5% (N = 733/776); 624/733 (85.1%) had home interviews, and 408/624 (65.4%) had a nurse come to the home for the blood draw. African American race was an independent predictor of participation in in-home assessments, but African American race and rural residence were independent predictors of not participating in a blood draw. Recruitment efforts designed to demonstrate respect for all research participants, home visits, and telephone follow-up interviews facilitate high retention rates for both African American and White older adults; however, additional efforts are required to enhance participation of African American and rural participants in research requiring blood draws.

Career satisfaction and retention risk among Wisconsin internists.

PubMed

Giriyappa, Pradeep; Sullivan, Kandis K

2009-09-01

Physician career satisfaction has been studied extensively, but career satisfaction as it relates to retention is less well studied. The objective was to assess the relationship between career satisfaction and retention in primary care internal medicine physicians in Wisconsin. In this descriptive quantitative study, survey data was assessed for correlations between career satisfaction, risk to retention, and demographics. The survey included 1231 primary care internal medicine physicians in the Wisconsin Medical Directory (2007). Responses were measured by career satisfaction variables, and demographics and retention variables for the purpose of correlations and regression analysis. Survey responses included 573 physicians. An additional 85 physicians were disqualified. The final survey group included 1146 physicians for a response rate of 50%. A total of 116 physicians (20.2%) reported anticipating leaving their current position, 84 (14.7%) physicians reported anticipating leaving the career of medicine. Identified at risk for retention were 144 (25.1%) physicians. The lowest career satisfaction scores were reported in the areas of compensation (3.19) and practice (3.42) on a scale of 1 (very dissatisfied) to 5 (very satisfied). The highest correlations to retention were associated with practice, followed by compensation satisfaction. The level of significance for this study was identified as 0.05, and the P-value was 0.000. The study findings reveal a significant risk to the stability of continuity of care for patients, and may cost Wisconsin health care organizations more than $35 million in recruitment costs to replace departing physicians.

Explicit role of ionic strength in retention behavior of polystyrene latex particles in sedimentation field-flow fractionation: Slip boundary model.

PubMed

Rah, Kyunil; Han, Sujeong; Choi, Jaeyeong; Eum, Chul Hun; Lee, Seungho

2017-12-15

We investigate an explicit role of the ionic strength in the retention behaviors of polystyrene (PS) latex particles in sedimentation field-flow fractionation (SdFFF) by hinging upon the retention theory recently developed [1] asR=(R o +v b * )/(1+v b * ). Here R is an experimental retention ratio, and R o is the analytical expression of the standard retention theory based on the parabolic flow velocity. The reduced boundary velocityv b * is expressed in terms of the ionic strength I of the carrier liquid as v b * =v b,o * /(1+εI), where v b,o * =0.070and ε=60 mM -1 for all the PS latex systems under investigation. We then apply this to study the explicit ionic strength effect on the retention behaviors of PS beads of 200, 300, 400, and 500nm, respectively. As a primary result, the strong dependence of the retention ratio on the ionic strength can be quantitatively accounted for in an excellent accuracy: The slip effect at the channel surface is significant, particularly when I≲0.5mM, without showing any distinguishable dependence on the specific additives to control I, such as FL-70, SDS, NaNO 3 , and NaN 3 . Based on the present study, we put forward an experimental means to estimate the ionic strength of an aqueous solution using an FFF technique. Copyright © 2017. Published by Elsevier B.V.

An Analysis of Tonal Patterns Used for Sight-Singing Instruction in Second-Grade General Music Class

ERIC Educational Resources Information Center

Reifinger, James L., Jr.

2009-01-01

This research examined characteristics of a select group of tonal patterns to identify features that may affect the initial acquisition of skill in sight-singing pitch. Second graders (N = 193) individually read and sang 25 tonal patterns on a sight-singing pretest, posttest, and retention test. Between the pre- and posttest, the students…

Impact of WhatsAPP on Learning and Retention of Collocation Knowledge among Iranian EFL Learners

ERIC Educational Resources Information Center

Ashiyan, Zahra; Salehi, Hadi

2016-01-01

During the recent technological years, language learning has been attempted to transform its path from the conventional methods to instrumental applications. Mobile phone provides people to reach and exchange information through chats (WhatsApp). It is a tool or mode that means the facilities are used for main purposes. The unique features of the…

Binding of Verbal and Spatial Features in Auditory Working Memory

ERIC Educational Resources Information Center

Maybery, Murray T.; Clissa, Peter J.; Parmentier, Fabrice B. R.; Leung, Doris; Harsa, Grefin; Fox, Allison M.; Jones, Dylan M.

2009-01-01

The present study investigated the binding of verbal identity and spatial location in the retention of sequences of spatially distributed acoustic stimuli. Study stimuli varying in verbal content and spatial location (e.g. V[subscript 1]S[subscript 1], V[subscript 2]S[subscript 2], V[subscript 3]S[subscript 3], V[subscript 4]S[subscript 4]) were…

Analogue evaluation of the effects of opportunities to respond and ratios of known items within drill rehearsal of Esperanto words.

PubMed

Szadokierski, Isadora; Burns, Matthew K

2008-10-01

Drill procedures have been used to increase the retention of various types of information, but little is known about the causal mechanisms of these techniques. The current study compared the effect of two key features of drill procedures, a large number of opportunities to respond (OTR) and a drill ratio that maintains a high percentage of known to unknown items (90% known). Using a factorial design, 27 4th graders were taught the pronunciation and meaning of Esperanto words using four versions of incremental rehearsal that varied on two factors, percentage of known words (high - 90% vs. moderate - 50%) and the number of OTR (high vs. low). A within-subject ANOVA revealed a significant main effect for OTR and non-significant effects for drill ratio and the interaction between the two variables. Moreover, it was found that increasing OTR from low to high yielded a large effect size (d=2.46), but increasing the percentage of known material from moderate (50%) to high (90%) yielded a small effect (d=0.16). These results suggest that a high number of OTR may be a key feature of flashcard drill techniques in promoting learning and retention.

Assessing the effect, on animal model, of mixture of food additives, on the water balance.

PubMed

Friedrich, Mariola; Kuchlewska, Magdalena

2013-01-01

The purpose of this study was to determine, on the animal model, the effect of modification of diet composition and administration of selected food additives on water balance in the body. The study was conducted with 48 males and 48 females (separately for each sex) of Wistar strain rats divided into four groups. For drinking, the animals from groups I and III were receiving water, whereas the animals from groups II and IV were administered 5 ml of a solution of selected food additives (potassium nitrate - E 252, sodium nitrite - E 250, benzoic acid - E 210, sorbic acid - E 200, and monosodium glutamate - E 621). Doses of the administered food additives were computed taking into account the average intake by men, expressed per body mass unit. Having drunk the solution, the animals were provided water for drinking. The mixture of selected food additives applied in the experiment was found to facilitate water retention in the body both in the case of both male and female rats, and differences observed between the volume of ingested fluids and the volume of excreted urine were statistically significant in the animals fed the basal diet. The type of feed mixture provided to the animals affected the site of water retention - in the case of animals receiving the basal diet analyses demonstrated a significant increase in water content in the liver tissue, whereas in the animals fed the modified diet water was observed to accumulate in the vascular bed. Taking into account the fact of water retention in the vascular bed, the effects of food additives intake may be more adverse in the case of females.

Comparison of retention and stability of implant-retained overdentures based upon implant number and distribution.

PubMed

Scherer, Michael D; McGlumphy, Edwin A; Seghi, Robert R; Campagni, Wayne V

2013-01-01

The purpose of this investigation was to evaluate the effects of number and distribution of implants upon in vitro dislodging forces to a simulated implant-supported overdenture and to examine differences between several different attachment systems. An experiment was undertaken utilizing a model simulating a mandibular edentulous ridge with dental implants in positions on the model approximating tooth positions in the natural dentition. A cobalt-chromium-cast testing framework was used to measure the peak load required to disconnect an attachment. Four different types of commercially available attachments were used in various positions on the model in sequence to evaluate the effects of retention and stability of overdentures based on implant number and distribution: (1) ERA, (2) O-Ring, (3) Locator, and (4) Ball. For each group, 10 measurements were made of peak dislodging forces. Means were calculated and differences among the systems, directions, and groups were identified using a repeated measured analysis of variance (α = .05). The interactions between the attachment system, direction of force, and implant number and distribution were statistically significant. Vertical dislodging forces of the simulated overdenture prosthesis increased with additional widely spaced implants. Oblique dislodging forces of the simulated prosthesis increased with additional widely spaced implants except in the two-implant model with all attachments, and in the four-implant groups with Locator attachments. Anteroposterior dislodging forces of a simulated overdenture prosthesis increased with additional widely spaced implants except in the four-implant groups with Ball and Locator attachments. Ball attachments reported the highest levels of retention and stability followed by Locator, O-Ring, and ERA. Within the limitations of this study, retention and stability of an implant overdenture prosthesis are significantly affected by implant number, implant distribution, and abutment type.

The influence of addition of ion-pairing acid and organic modifier of the mobile phase on retention and migration of peptides in pressurized planar electrochromatography system with octadecyl silica-based adsorbent.

PubMed

Gwarda, Radosław Ł; Dzido, Tadeusz H

2018-07-13

In our previous papers we have investigated the influence of the mobile phase composition on mechanism of retention, selectivity and efficiency of peptide separation in various high-performance thin-layer chromatography (HPTLC) systems with commercially available silica-based adsorbents. We have also investigated the influence of pH of the mobile phase buffer on migration and separation of peptides in pressurized planar electrochromatography (PPEC). Here we investigate the influence of concentration of ion-pairing additive, and concentration and type of organic modifier of the mobile phase on migration of peptides in PPEC system with octadecyl silica-based adsorbent, and with the same set of the solutes as before. We compare our current results with the results obtained before for similar HPTLC and PPEC systems, and discuss the influence of particular variables on retention, electrophoretic mobility of solutes and electroosmotic flow of the mobile phase. We show, that the final selectivity of peptide separation results from co-influence of all the three factors mentioned. Concentration of organic modifier of the mobile phase, as well as concentration of ion-pairing additive, affect the retention, the electrophoretic mobility, and the electroosmotic flow simultaneously. This makes independent optimization of these factors rather difficult. Anyway PPEC offers much faster separation of peptides with quite different selectivity, in comparison to HPTLC, with similar adsorbents and similar mobile phase composition. However, we also present and discuss the issue of extensive tailing of peptide zones in the PPEC in comparison to similar HPTLC systems. Copyright © 2018 Elsevier B.V. All rights reserved.

Enrichment of denitrifying methanotrophic bacteria from municipal wastewater sludge in a membrane bioreactor at 20°C.

PubMed

Kampman, Christel; Temmink, Hardy; Hendrickx, Tim L G; Zeeman, Grietje; Buisman, Cees J N

2014-06-15

Simultaneous nitrogen and methane removal by the slow growing denitrifying methanotrophic bacterium 'Candidatus Methylomirabilis oxyfera' offers opportunities for a new approach to wastewater treatment. However, volumetric nitrite consumption rates should be increased by an order of magnitude before application in wastewater treatment becomes possible. A maximum volumetric nitrite consumption rate of 36 mg NO2(-)-N/L d was achieved in a membrane bioreactor inoculated with wastewater sludge and operated at 20°C. This rate is similar to maximum rates reported in literature, though it was thought that by strict biomass retention using membranes, higher rates would be achieved. In experiments lasting several years, growth was not stable: every experiment showed a decrease in activity after 1-2 years. The cause remains unknown. Rates increased after addition of copper and operating a membrane bioreactor at shorter hydraulic retention times. Further research should focus on long-term effects of copper addition and operation at hydraulic retention times in the order of hours using membrane bioreactors. Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of strontium metabolism in humans on the basis of the Techa river data

NASA Technical Reports Server (NTRS)

Tolstykh, E. I.; Kozheurov, V. P.; Vyushkova, O. V.; Degteva, M. O.; Neta, R. (Principal Investigator)

1997-01-01

Age and sex features of strontium metabolism have been analyzed on studies of the population residing on the banks of the Techa river which was contaminated by fission products during the years 1949-1956. Measurements of 90Sr body burden have been performed since 1974 using a whole-body counter, and these have made it possible to estimate age-specific long-term retention and elimination rates for men and women. Regarding the retention that correlated with the respective maturation ages, distinct sex differences have been observed for adolescents, whereas only postmenopausal women showed a sharp increase of their elimination rates. There were no differences concerning the reproductive ages. Our experimental findings have a clear physiological interpretation and can be used to develop metabolic models for bone-seeking radionuclides.

Factors affecting the retention of first-year female science and engineering students at the University of Michigan

NASA Astrophysics Data System (ADS)

Ballard, Juliet Webb

Alarming to many academics is that while the numbers of female students (at the University of Michigan in particular) in SEM (Science, Engineering, and Mathematics) departments have shown increases in enrollment over the past decades, the number of female professionals in the field has decreased. The purpose of the study was to determine the environmental perceptions of female SEM students in the Women in Science and Engineering (WISE) Program at the University of Michigan. The WISE-RP (Residence Program) is an existing living and learning education program at the university that was designed to facilitate the successful retention and graduation of undergraduate female SEM students in the capacity that the admissions statistics should logically imply. The objectives of the study included identification of the perceptions of female students that contribute to, and foster retention of students participating in the WISE-RP program. The knowledge obtained from this evaluation will guide the University of Michigan in formulating specific interventions and retention approaches, both in and out of the classroom. This was achieved by identifying (among other things) commonality of experiences, and female student's perceptions of acceptance, integration and interactivity. The data used in this secondary analysis was collected over a 2 year period (1999--2001). The primary instrument used for data collection was a structured interview protocol utilizing focus groups. The population and samples studied were comprised of: a research project consisting of 36 focus groups from WISE-RP, University Research Opportunity Program, and the University Research Opportunity in Residence Programs; the sample size of the initial project was 180 first year SEM male and female students. The research project consisted of working with a senior research team at the University of Michigan to develop a structured interview instrument, pilot the instrument, and select focus groups. Content analysis was conducted on the open-ended focus group questions. Three themes emerged from the data set: (a) general contributing factors to retention, (b) support networks and programmatic features that contributed to retention, (c) individual/gender specific challenges that students faced. It found that the initial mission of the program has been accomplished, as evidenced by the findings of this study. The University is graduating and retaining female SEM students at a higher rate than at the program's inception. The challenges for the University at this point include: increasing numbers of female SEM faculty, enhancing and focusing the living learning community mission of the program, integrating student affairs components to the program features on an administrative level, committing to longitudinal analysis and assessment of individual incoming students toward identifying strengths and weaknesses, and finally---committing increased resources to these objectives.

Sweeping as a multistep enrichment process in micellar electrokinetic chromatography: the retention factor gradient effect.

PubMed

El-Awady, Mohamed; Pyell, Ute

2013-07-05

The application of a new method developed for the assessment of sweeping efficiency in MEKC under homogeneous and inhomogeneous electric field conditions is extended to the general case, in which the distribution coefficient and the electric conductivity of the analyte in the sample zone and in the separation compartment are varied. As test analytes p-hydroxybenzoates (parabens), benzamide and some aromatic amines are studied under MEKC conditions with SDS as anionic surfactant. We show that in the general case - in contrast to the classical description - the obtainable enrichment factor is not only dependent on the retention factor of the analyte in the sample zone but also dependent on the retention factor in the background electrolyte (BGE). It is shown that in the general case sweeping is inherently a multistep focusing process. We describe an additional focusing/defocusing step (the retention factor gradient effect, RFGE) quantitatively by extending the classical equation employed for the description of the sweeping process with an additional focusing/defocusing factor. The validity of this equation is demonstrated experimentally (and theoretically) under variation of the organic solvent content (in the sample and/or the BGE), the type of organic solvent (in the sample and/or the BGE), the electric conductivity (in the sample), the pH (in the sample), and the concentration of surfactant (in the BGE). It is shown that very high enrichment factors can be obtained, if the pH in the sample zone makes possible to convert the analyte into a charged species that has a high distribution coefficient with respect to an oppositely charged micellar phase, while the pH in the BGE enables separation of the neutral species under moderate retention factor conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of repeated administration of chemotherapeutic agents tamoxifen, methotrexate, and 5-fluorouracil on the acquisition and retention of a learned response in mice

PubMed Central

Foley, John J.; Clark-Vetri, Rachel; Raffa, Robert B.

2011-01-01

Rationale A number of cancer chemotherapeutic agents have been associated with a loss of memory in breast cancer patients although little is known of the causality of this effect. Objectives To assess the potential cognitive effects of repeated exposure to chemotherapeutic agents, we administered the selective estrogen receptor modulator tamoxifen or the antimetabolite chemotherapy, methotrexate, and 5-fluorouracil, alone and in combination to mice and tested them in a learning and memory assay. Methods Swiss-Webster male mice were injected with saline, 32 mg/kg tamoxifen, 3.2 or 32 mg/kg methotrexate, 75 mg/kg 5-fluorouracil, 3.2 or 32 mg/kg methotrexate in combination with 75 mg/kg 5-fluorouracil once per week for 3 weeks. On days 23 and 24, mice were tested for acquisition and retention of a nose-poke response in a learning procedure called autoshaping. In addition, the acute effects of tamoxifen were assessed in additional mice in a similar procedure. Results The chemotherapeutic agents alone and in combination reduced body weight relative to saline treatment over the course of 4 weeks. Repeated treatment with tamoxifen produced both acquisition and retention effects relative to the saline-treated group although acute tamoxifen was without effect except at a behaviorally toxic dose. Repeated treatment with methotrexate in combination with 5-fluorouracil produced effects on retention, but the magnitude of these changes depended on the methotrexate dose. Conclusions These data demonstrate that repeated administration of tamoxifen or certain combination of methotrexate and 5-fluorouracil may produce deficits in the acquisition or retention of learned responses which suggest potential strategies for prevention or remediation might be considered in vulnerable patient populations. PMID:21537942

Effects of a protease and essential oils on growth performance, blood cell profiles, nutrient retention, ileal microbiota, excreta gas emission, and breast meat quality in broiler chicks.

PubMed

Park, J H; Kim, I H

2018-05-19

A total of 360 Ross male broiler chicks (39.8 ± 1.8 g) were used in a five week experiment to determine the effect of a protease and essential oils (EO) on growth performance, blood cell profile, nutrient retention, ileal microbiota, excreta gas emission, and breast meat quality in broiler chicks. Broiler chicks were randomly allotted to four dietary treatments with 15 birds/cage and six cages/treatment. Experimental treatments were arranged as a 2 × 2 factorial with two levels of protease (0 and 0.02%) and two levels of EO (0 and 0.03%). For days 8 to 21 and overall, body weight gain and the feed conversion ratio were better in broilers fed diets supplemented with protease (P < 0.05) than in those fed diets without protease supplementation. Protease and/or EO increased (P < 0.05) the total tract retention of dry matter, nitrogen, or gross energy, and decreased the excreta ammonia gas emission. In addition, there was a significant interaction between the protease and EO on total tract retention of nitrogen and excreta ammonia gas emission (P < 0.05). The density of ileal Lactobacillus increased and Escherichia coli decreased in broilers (P < 0.05) by the addition of EO to the diet. There were no significant differences in the measurements of breast meat quality and organ weight of broilers fed diets with protease or EO. In conclusion, diets with a combination of a protease and EO improved total tract retention of nitrogen and excreta ammonia gas emission in growing broiler chicks.

Correlation between structure, retention, property, and activity of biologically relevant 1,7-bis(aminoalkyl)diazachrysene derivatives.

PubMed

Šegan, Sandra; Trifković, Jelena; Verbić, Tatjana; Opsenica, Dejan; Zlatović, Mario; Burnett, James; Šolaja, Bogdan; Milojković-Opsenica, Dušanka

2013-01-01

The physicochemical properties, retention parameters (R(M)(0)), partition coefficients (logP(OW)), and pK(a) values for a series of thirteen 1,7-bis(aminoalkyl) diazachrysene (1,7-DAAC) derivatives were determined in order to reveal the characteristics responsible for their biological behavior. The investigated compounds inhibit three unrelated pathogens (the Botulinum neurotoxin serotype A light chain (BoNT/A LC), Plasmodium falciparum malaria, and Ebola filovirus) via three different mechanisms of action. To determine the most influential factors governing the retention and activities of the investigated diazachrysenes, R(M)(0), logP(OW), and biological activity values were correlated with 2D and 3D molecular descriptors, using a partial least squares regression. The resulting quantitative structure-retention (property) relationships indicate the importance of descriptors related to the hydrophobicity of the molecules (e.g., predicted partition coefficients and hydrophobic surface area). Quantitative structure-activity relationship models for describing biological activity against the BoNT/A LC and malarial strains also include overall compound polarity, electron density distribution, and proton donor/acceptor potential. Furthermore, models for Ebola filovirus inhibition are presented qualitatively to provide insights into parameters that may contribute to the compounds' antiviral activities. Overall, the models form the basis for selecting structural features that significantly affect the compound's absorption, distribution, metabolism, excretion, and toxicity profiles. Copyright © 2012 Elsevier B.V. All rights reserved.

Developing a neonatal workforce: role evolution and retention of advanced neonatal nurse practitioners

PubMed Central

Smith, S; Hall, M

2003-01-01

Background: Over the past decade more than 120 advanced neonatal nurse practitioners (ANNPs) have graduated from the Southampton based ANNP programme. Objectives: To determine the scope of practice and evolving role of ANNPs and to identify factors that may affect future recruitment and retention. Method: An open ended structured questionnaire on clinical role, working arrangements, retention and attrition, continuing education, and professional development was sent to 95 ANNPs. Results: A response rate of 83% was achieved. There was an attrition rate of 14%, with most ANNPs remaining in their original seconding unit. Factors considered to be important for role satisfaction included a well defined role, working within a team of ANNPs, appropriate remuneration, and evidence of unit support for both role definition and continuing professional development. Conclusions: Although ANNPs are expensive to both train and employ, this evidence suggests that there is a good return on the investment in terms of retention to the unit and the specialty. Their role incorporates many features of advanced nursing practice as well as providing "value added" neonatal care by merging traditional medical and nursing roles and crossing professional boundaries. In 2004 the manpower challenges for neonatal units will be even more acute; these data confirm that there are effective options available but they require long term strategic planning and investment. PMID:12937050

Encoding vs. retention: differential effects of cue manipulation on working memory performance in schizophrenia.

PubMed

Javitt, Daniel C; Rabinowicz, Esther; Silipo, Gail; Dias, Elisa C

2007-03-01

Deficits in working memory performance are among the most widely replicated findings in schizophrenia. Roles of encoding vs. memory retention in working memory remain unresolved. The present study evaluated working memory performance in schizophrenia using an AX-type continuous performance test (AX-CPT) paradigm. Participants included 48 subjects with schizophrenia and 27 comparison subjects. Behavior was obtained in 3 versions of the task, which differed based upon ease of cue interoperability. In a simple cue version of the task, cue letters were replaced with red or green circles. In the complex cue version, letter/color conjunctions served as cues. In the base version of the task, patients showed increased rates of false alarms to invalidly cued targets, similar to prior reports. However, when the cue stimuli were replaced with green or red circles to ease interpretation, patients showed similar false alarm rates to controls. When feature conjunction cues were used, patients were also disproportionately affected relative to controls. No significant group by interstimulus interval interaction effects were observed in either the simple or complex cue conditions, suggesting normal retention of information even in the presence of overall performance decrements. These findings suggest first, that cue manipulation disproportionately affects AX-CPT performance in schizophrenia and, second, that substantial behavioral deficits may be observed on working memory tasks even in the absence of disturbances in mnemonic retention.

Establishment of a reference collection of additives and an analytical handbook of reference data to support enforcement of EU regulations on food contact plastics.

PubMed

van Lierop, B; Castle, L; Feigenbaum, A; Ehlert, K; Boenke, A

1998-10-01

A collection has been made of additives that are required as analytical standards for enforcement of European Union legislation on food contact plastics. The 100 additives have been characterized by mass spectrometry, infra-red spectroscopy and proton nuclear magnetic resonance spectroscopy to provide reference spectra. Gas chromatographic retention times have been recorded to facilitate identification by retention index. This information has been further supplemented by physico-chemical data. Finally, chromatographic methods have been used to indicate the presence of any impurities in the commercial chemicals. Samples of the reference substances are available on request and the collection of spectra and other information will be made available in printed format and on-line through the Internet. This paper gives an overview of the work done to establish the reference collection and the spectral atlas, which together will assist enforcement laboratories in the characterization of plastics and the selection of analytical methods for additives that may migrate.

The relationship between visual working memory and attention: retention of precise colour information in the absence of effects on perceptual selection.

PubMed

Hollingworth, Andrew; Hwang, Seongmin

2013-10-19

We examined the conditions under which a feature value in visual working memory (VWM) recruits visual attention to matching stimuli. Previous work has suggested that VWM supports two qualitatively different states of representation: an active state that interacts with perceptual selection and a passive (or accessory) state that does not. An alternative hypothesis is that VWM supports a single form of representation, with the precision of feature memory controlling whether or not the representation interacts with perceptual selection. The results of three experiments supported the dual-state hypothesis. We established conditions under which participants retained a relatively precise representation of a parcticular colour. If the colour was immediately task relevant, it reliably recruited attention to matching stimuli. However, if the colour was not immediately task relevant, it failed to interact with perceptual selection. Feature maintenance in VWM is not necessarily equivalent with feature-based attentional selection.

Character and spatial distribution of OH/H2O on the surface of the Moon seen by M3 on Chandrayaan-1.

PubMed

Pieters, C M; Goswami, J N; Clark, R N; Annadurai, M; Boardman, J; Buratti, B; Combe, J-P; Dyar, M D; Green, R; Head, J W; Hibbitts, C; Hicks, M; Isaacson, P; Klima, R; Kramer, G; Kumar, S; Livo, E; Lundeen, S; Malaret, E; McCord, T; Mustard, J; Nettles, J; Petro, N; Runyon, C; Staid, M; Sunshine, J; Taylor, L A; Tompkins, S; Varanasi, P

2009-10-23

The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M3) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration.

Character and spatial distribution of OH/H2O on the surface of the moon seen by M3 on chandrayaan-1

USGS Publications Warehouse

Pieters, C.M.; Goswami, J.N.; Clark, R.N.; Annadurai, M.; Boardman, J.; Buratti, B.; Combe, J.-P.; Dyar, M.D.; Green, R.; Head, J.W.; Hibbitts, C.; Hicks, M.; Isaacson, P.; Klima, R.; Kramer, G.; Kumar, S.; Livo, E.; Lundeen, S.; Malaret, E.; McCord, T.; Mustard, J.; Nettles, J.; Petro, N.; Runyon, C.; Staid, M.; Sunshine, J.; Taylor, L.A.; Tompkins, S.; Varanasi, P.

2009-01-01

The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M 3) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration.

Does moonlighting influence South African nurses' intention to leave their primary jobs?

PubMed

Rispel, Laetitia C; Chirwa, Tobias; Blaauw, Duane

2014-01-01

Staff retention and turnover have risen in prominence in the global discourse on the health workforce. Moonlighting, having a second job in addition to a primary job, has not featured in debates on turnover. This paper examines whether moonlighting is a determinant of South African nurses' intention to leave their primary jobs. During 2010, a one-stage cluster random sample of 80 hospitals was selected in four South African provinces. On the survey day, all nurses working in critical care, theatre, emergency, maternity, and general medical and surgical wards completed a self-administered questionnaire after giving informed consent. In addition to demographic information and information on moonlighting, the questionnaire obtained information on the participants' intention to leave their primary jobs in the 12 months following the survey. A weighted analysis of the survey data was done using STATA(®) 13. Survey participants (n=3,784) were predominantly middle-aged with a mean age of 41.5 (SD±10.4) years. Almost one-third of survey participants (30.9%) indicated that they planned to leave their jobs within 12 months. Intention to leave was higher among the moonlighters (39.5%) compared to non-moonlighters (27.9%; p<0.001). Predictors of intention to leave in a multiple logistic regression were moonlighting in the preceding year, nursing category, sector of primary employment, period working at the primary job, and number of children. The odds of intention to leave was 1.40 (95% CI: 1.16-1.69) times higher for moonlighters than for non-moonlighters. The odds ratio of intention to leave was 0.53 (95% CI: 0.42-0.66) for nursing assistants compared to professional nurses and 2.09 (95% CI: 1.49-2.94) for nurses working for a commercial nursing agency compared to those working in the public sector. Moonlighting is a predictor of intention to leave. Both individual and organisational strategies are needed to manage moonlighting and to enhance retention among South African nurses.

Combined effects of local habitat, anthropogenic stress, and dispersal on stream ecosystems: a mesocosm experiment.

PubMed

Turunen, Jarno; Louhi, Pauliina; Mykrä, Heikki; Aroviita, Jukka; Putkonen, Emmi; Huusko, Ari; Muotka, Timo

2018-06-06

The effects of anthropogenic stressors on community structure and ecosystem functioning can be strongly influenced by local habitat structure and dispersal from source communities. Catchment land uses increase the input of fine sediments into stream channels, clogging the interstitial spaces of benthic habitats. Aquatic macrophytes enhance habitat heterogeneity and mediate important ecosystem functions, being thus a key component of habitat structure in many streams. Therefore, the recovery of macrophytes following in-stream habitat modification may be prerequisite for successful stream restoration. Restoration success is also affected by dispersal of organisms from the source community, with potentially strongest responses in relatively isolated headwater sites that receive limited amount of dispersing individuals. We used a factorial design in a set of stream mesocosms to study the independent and combined effects of an anthropogenic stressor (sand sedimentation), local habitat (macrophytes, i.e. moss transplants) and enhanced dispersal (two levels: high vs. low) on organic matter retention, algal accrual rate, leaf decomposition and macroinvertebrate community structure. Overall, all responses were simple additive effects with no interactions between treatments. Sand reduced algal accumulation, total invertebrate density and density of a few individual taxa. Mosses reduced algal accrual rate and algae-grazing invertebrates, but enhanced organic matter retention and detritus- and filter-feeders. Mosses also reduced macroinvertebrate diversity by increasing the dominance by a few taxa. Mosses also reduced leaf-mass loss, possibly because the organic matter retained by mosses provided an additional food source for leaf-shredding invertebrates and thus reduced shredder aggregation into leaf packs. The effect of mosses on macroinvertebrate communities and ecosystem functioning was distinct irrespective of the level of dispersal, suggesting strong environmental control of community structure. The strong environmental control of macroinvertebrate community composition even under enhanced dispersal suggests that re-establishing key habitat features, such as natural stream vegetation, could aid ecosystem recovery in boreal streams. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Physical study of minced fish muscle with a white-grape by-product added as an ingredient.

PubMed

Sánchez-Alonso, I; Solas, M T; Borderías, A J

2007-03-01

Functional properties of a white grape dietary fiber concentrate (WGDF) obtained from wine industry residues were determined with a view to their use as potential functional ingredient in seafood products. The main features of interest of WGDF are that it is a natural product containing high concentrations of dietary fiber (DF) with a high-soluble DF (sDF)/insoluble DF (iDF) ratio and associated bioactive compounds; as such it is considered potentially suitable for use as dietary fiber in the enrichment of foods. WGDF was therefore added to minced fish muscle (MFM) of horse mackerel (Trachurus trachurus) to take advantage of its technological properties, and also to enrich a food product that is a functional product in itself but does not contain dietary fiber. WGDF was added (2% and 4%) to MFM, which was stored for 6 mo at -20 degrees C, and a further lot was vacuum packed. Physical and mechanical properties, sensory and color analyses, microscopy, and electrophoretic profiles were all done in samples every month. The results indicate that WGDF had good functional properties, high water and oil retention capacity, and considerable swelling properties, which would make it useful as a natural ingredient in foods. The addition of WGDF to MFM augmented aggregation of myofibrillar proteins in the course of frozen storage, although electrophoretic profiles were very similar in samples with and without WGDF. The addition of WGDF to MFM made samples softer and less springy and cohesive. SEM showed good dispersion of WGDF in MFM but the matrix was more discontinuous than in the control. Water retention was significantly enhanced when WGDF was added, and the cooking yield improved. In sensory evaluation, samples containing 2% of WGDF scored highest in overall acceptance as compared with the control. Vacuum packing did not significantly affect the properties considered during frozen storage.

Improving low fat meatball characteristics by adding whey powder.

PubMed

Serdaroğlu, Meltem

2006-01-01

In this study whey powder (WP) at levels of 0%, 2% and 4% was added to beef meatballs formulated with 5%, 10% and 20% fat levels. Raw and cooked meatballs were analyzed for protein, fat, moisture, ash and pH. Meatballs were evaluated for cooking characteristics, juiciness, colour parameters (L*,a*,b*) and sensory properties. Addition of WP did not affect fat and protein contents of meatballs. Addition of 2% or 4% WP significantly increased cooking yield regardless of the fat level. Both fat level and WP level significantly affected fat retention values of meatballs. Incorporating WP had no effect on meatball juiciness. Addition of WP increased fat and moisture retention of meatballs. Twenty percent fat resulted in higher L* and lower a* values. Adding WP resulted in higher L* values but WP had no effect on a* and b* values. WP had no detrimental effect on sensory properties.

Critical evaluation of a simple retention time predictor based on LogKow as a complementary tool in the identification of emerging contaminants in water.

PubMed

Bade, Richard; Bijlsma, Lubertus; Sancho, Juan V; Hernández, Felix

2015-07-01

There has been great interest in environmental analytical chemistry in developing screening methods based on liquid chromatography-high resolution mass spectrometry (LC-HRMS) for emerging contaminants. Using HRMS, compound identification relies on the high mass resolving power and mass accuracy attainable by these analyzers. When dealing with wide-scope screening, retention time prediction can be a complementary tool for the identification of compounds, and can also reduce tedious data processing when several peaks appear in the extracted ion chromatograms. There are many in silico, Quantitative Structure-Retention Relationship methods available for the prediction of retention time for LC. However, most of these methods use commercial software to predict retention time based on various molecular descriptors. This paper explores the applicability and makes a critical discussion on a far simpler and cheaper approach to predict retention times by using LogKow. The predictor was based on a database of 595 compounds, their respective LogKow values and a chromatographic run time of 18min. Approximately 95% of the compounds were found within 4.0min of their actual retention times, and 70% within 2.0min. A predictor based purely on pesticides was also made, enabling 80% of these compounds to be found within 2.0min of their actual retention times. To demonstrate the utility of the predictors, they were successfully used as an additional tool in the identification of 30 commonly found emerging contaminants in water. Furthermore, a comparison was made by using different mass extraction windows to minimize the number of false positives obtained. Copyright © 2015 Elsevier B.V. All rights reserved.

Reversal of Long-Term Potentiation-Like Plasticity Processes after Motor Learning Disrupts Skill Retention

PubMed Central

Cantarero, Gabriela; Lloyd, Ashley

2013-01-01

Plasticity of synaptic connections in the primary motor cortex (M1) is thought to play an essential role in learning and memory. Human and animal studies have shown that motor learning results in long-term potentiation (LTP)-like plasticity processes, namely potentiation of M1 and a temporary occlusion of additional LTP-like plasticity. Moreover, biochemical processes essential for LTP are also crucial for certain types of motor learning and memory. Thus, it has been speculated that the occlusion of LTP-like plasticity after learning, indicative of how much LTP was used to learn, is essential for retention. Here we provide supporting evidence of it in humans. Induction of LTP-like plasticity can be abolished using a depotentiation protocol (DePo) consisting of brief continuous theta burst stimulation. We used transcranial magnetic stimulation to assess whether application of DePo over M1 after motor learning affected (1) occlusion of LTP-like plasticity and (2) retention of motor skill learning. We found that the magnitude of motor memory retention is proportional to the magnitude of occlusion of LTP-like plasticity. Moreover, DePo stimulation over M1, but not over a control site, reversed the occlusion of LTP-like plasticity induced by motor learning and disrupted skill retention relative to control subjects. Altogether, these results provide evidence of a link between occlusion of LTP-like plasticity and retention and that this measure could be used as a biomarker to predict retention. Importantly, attempts to reverse the occlusion of LTP-like plasticity after motor learning comes with the cost of reducing retention of motor learning. PMID:23904621

Motivational Interviewing to prevent dropout from an education and employment program for young adults: A randomized controlled trial.

PubMed

Sayegh, Caitlin S; Huey, Stanley J; Barnett, Elizabeth; Spruijt-Metz, Donna

2017-07-01

This study tested the efficacy of Motivational Interviewing for improving retention at a "second chance" program in the United States for unemployed young adults who had not graduated high school (ages 18-24; 60% male). We investigated how Motivational Interviewing effects might be mediated by change talk (i.e., arguments for change) and moderated by preference for consistency (PFC). Participants (N = 100) were randomly assigned to (1) Motivational Interviewing designed to elicit change talk, (2) placebo counseling designed not to elicit change talk, or (3) no additional treatment. Motivational Interviewing sessions increased change talk, but did not increase program retention or diploma earning. PFC was a significant moderator of Motivational Interviewing's impact on program retention; Motivational Interviewing was most effective at increasing 8 week retention for high PFC participants, and least effective for low PFC participants. These results suggest that Motivational Interviewing could be a useful tool for improving retention in education and employment programs, but clinicians should be attentive to how participant characteristics might enhance or diminish Motivational Interviewing effects. Copyright © 2017 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Retention Model of TaO/HfO x and TaO/AlO x RRAM with Self-Rectifying Switch Characteristics.

PubMed

Lin, Yu-De; Chen, Pang-Shiu; Lee, Heng-Yuan; Chen, Yu-Sheng; Rahaman, Sk Ziaur; Tsai, Kan-Hsueh; Hsu, Chien-Hua; Chen, Wei-Su; Wang, Pei-Hua; King, Ya-Chin; Lin, Chrong Jung

2017-12-01

A retention behavior model for self-rectifying TaO/HfO x - and TaO/AlO x -based resistive random-access memory (RRAM) is proposed. Trapping-type RRAM can have a high resistance state (HRS) and a low resistance state (LRS); the degradation in a LRS is usually more severe than that in a HRS, because the LRS during the SET process is limited by the internal resistor layer. However, if TaO/AlO x elements are stacked in layers, the LRS retention can be improved. The LRS retention time estimated by extrapolation method is more than 5 years at room temperature. Both TaO/HfO x - and TaO/AlO x -based RRAM structures have the same capping layer of TaO, and the activation energy levels of both types of structures are 0.38 eV. Moreover, the additional AlO x switching layer of a TaO/AlO x structure creates a higher O diffusion barrier that can substantially enhance retention, and the TaO/AlO x structure also shows a quite stable LRS under biased conditions.

A float mechanism of retention in reversed-phase chromatography

NASA Astrophysics Data System (ADS)

Deineka, V. I.; Deineka, L. A.; Saenko, I. I.; Chulkov, A. N.

2015-07-01

A float mechanism of retention in reversed-phase HPLC is proposed as an alternative to the known mechanisms of the distribution and hydrophobic expulsion of sorbate to the surface of a sorbent. Experimental data that the sorption of a flavylium structure is poorly sensitive to the position of OH groups, and that the retention of anthocyanins depends on the length of bonded alkyl radicals of reversed phase, form the basis of the proposed hypothesis. It is noted that the retention of anthocyanins depends on the orientation of hydroxyl groups in carbohydrate radicals, due to which the chromatographic behavior of anthocyanins is different for glucosides and galactosides, for arabinosides and xylosides, and so on. In other words, retention is a reliable indicator of the composition of a carbohydrate fragment. It is concluded that carbohydrate radicals serve as unique floats, while flat flavilic ions penetrate into the bonded phase. The existence of floats is the main reason for the lower efficiency (of the number of theoretical plates) of the peaks of anthocyanins. It is shown that if two carbohydrate radicals are present at different sites of aglycone (a two-float sorbate), the peaks of the substance are characterized by substantial additional broadening.

A microfluidic device for study of the effect of tumor vascular structures on the flow field and HepG2 cellular flow behaviors.

PubMed

Ke, Ming; Cai, Shaoxi; Zou, Misha; Zhao, Yi; Li, Bo; Chen, Sijia; Chen, Longcong

2018-01-29

To build a microfluidic device with various morphological features of the tumor vasculature for study of the effects of tumor vascular structures on the flow field and tumor cellular flow behaviors. The designed microfluidic device was able to approximatively simulate the in vivo structures of tumor vessels and the flow within it. In this models, the influences of the angle of bifurcation, the number of branches, and the narrow channels on the flow field and the influence of vorticity on the retention of HepG2 cells were significant. Additionally, shear stress below physiological conditions of blood circulation has considerable effect on the formation of the lumen-like structures (LLSs) of HepG2 cells. These results can provide some data and reference in the understanding of the interaction between hemorheological properties and tumor vascular structures in solid tumors. Copyright © 2018. Published by Elsevier Inc.

A time series approach to inferring groundwater recharge using the water table fluctuation method

NASA Astrophysics Data System (ADS)

Crosbie, Russell S.; Binning, Philip; Kalma, Jetse D.

2005-01-01

The water table fluctuation method for determining recharge from precipitation and water table measurements was originally developed on an event basis. Here a new multievent time series approach is presented for inferring groundwater recharge from long-term water table and precipitation records. Additional new features are the incorporation of a variable specific yield based upon the soil moisture retention curve, proper accounting for the Lisse effect on the water table, and the incorporation of aquifer drainage so that recharge can be detected even if the water table does not rise. A methodology for filtering noise and non-rainfall-related water table fluctuations is also presented. The model has been applied to 2 years of field data collected in the Tomago sand beds near Newcastle, Australia. It is shown that gross recharge estimates are very sensitive to time step size and specific yield. Properly accounting for the Lisse effect is also important to determining recharge.

On the relation between motivation and retention in educational contexts: The role of intentional and unintentional mind wandering.

PubMed

Seli, Paul; Wammes, Jeffrey D; Risko, Evan F; Smilek, Daniel

2016-08-01

Highly motivated students often exhibit better academic performance than less motivated students. However, to date, the specific cognitive mechanisms through which motivation increases academic achievement are not well understood. Here we explored the possibility that mind wandering mediates the relation between motivation and academic performance, and additionally, we examined possible mediation by both intentional and unintentional forms of mind wandering. We found that participants reporting higher motivation to learn in a lecture-based setting tended to engage in less mind wandering, and that this decrease in mind wandering was in turn associated with greater retention of the lecture material. Critically, we also found that the influence of motivation on retention was mediated by both intentional and unintentional types of mind wandering. Not only do the present results advance our theoretical understanding of the mechanisms underlying the relation between motivation and academic achievement, they also provide insights into possible methods of intervention that may be useful in improving student retention in educational settings.

Helium retention behavior in simultaneously He+-H2+ irradiated tungsten

NASA Astrophysics Data System (ADS)

Zhou, Qilai; Azuma, Keisuke; Togari, Akihiro; Yajima, Miyuki; Tokitani, Masayuki; Masuzaki, Suguru; Yoshida, Naoaki; Hara, Masanori; Hatano, Yuji; Oya, Yasuhisa

2018-04-01

The purpose of this study is to elucidate helium (He) retention behavior in tungsten (W) under simultaneous He and hydrogen (H) irradiation. Polycrystalline-W was irradiated by He+ and H2+ simultaneously with the energy of 1.0 keV and 3.0 keV. He+ fluences were (0.5, 1.0, 10) × 1021 He+ m-2 and H2+ fluence was 1.0 × 1022 H+ m-2,respectively. After irradiation, He desorption behavior was investigated by high temperature thermal desorption spectroscopy (HT-TDS) in the temperature range of R.T.-1773 K. Micro-structure changes of W after irradiation were observed by TEM. It was found that simultaneous irradiation with different H2+ energy significantly changed He retention behavior. 1.0 keV H2+ suppressed the He bubble growth and no bubbles can be observed at room temperature. On the other hand, 3.0 keV H2+ facilitated the formation of He bubbles and increased the He retention due to the additional damage introduction by energetic H2+.

Combustion characteristics and retention-emission of selenium during co-firing of torrefied biomass and its blends with high ash coal.

PubMed

Ullah, Habib; Liu, Guijian; Yousaf, Balal; Ali, Muhammad Ubaid; Abbas, Qumber; Zhou, Chuncai

2017-12-01

The combustion characteristics, kinetic analysis and selenium retention-emission behavior during co-combustion of high ash coal (HAC) with pine wood (PW) biomass and torrefied pine wood (TPW) were investigated through a combination of thermogravimetric analysis (TGA) and laboratory-based circulating fluidized bed combustion experiment. Improved ignition behavior and thermal reactivity of HAC were observed through the addition of a suitable proportion of biomass and torrefied. During combustion of blends, higher values of relative enrichment factors in fly ash revealed the maximum content of condensing volatile selenium on fly ash particles, and depleted level in bottom ash. Selenium emission in blends decreased by the increasing ratio of both PW and TPW. Higher reductions in the total Se volatilization were found for HAC/TPW than individual HAC sample, recommending that TPW have the best potential of selenium retention. The interaction amongst selenium and fly ash particles may cause the retention of selenium. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kidney Response to the Spectrum of Diet-Induced Acid Stress

PubMed Central

Goraya, Nimrit; Wesson, Donald E.

2018-01-01

Chronic ingestion of the acid (H+)-producing diets that are typical of developed societies appears to pose a long-term threat to kidney health. Mechanisms employed by kidneys to excrete this high dietary H+ load appear to cause long-term kidney injury when deployed over many years. In addition, cumulative urine H+ excretion is less than the cumulative increment in dietary H+, consistent with H+ retention. This H+ retention associated with the described high dietary H+ worsens as the glomerular filtration rate (GFR) declines which further exacerbates kidney injury. Modest H+ retention does not measurably change plasma acid–base parameters but, nevertheless, causes kidney injury and might contribute to progressive nephropathy. Current clinical methods do not detect H+ retention in its early stages but the condition manifests as metabolic acidosis as it worsens, with progressive decline of the glomerular filtration rate. We discuss this spectrum of H+ injury, which we characterize as “H+ stress”, and the emerging evidence that high dietary H+ constitutes a threat to long-term kidney health. PMID:29751620

Metal-ion retention properties of water-soluble amphiphilic block copolymer in double emulsion systems (w/o/w) stabilized by non-ionic surfactants.

PubMed

Palencia, Manuel; Rivas, Bernabé L

2011-11-15

Metal-ion retention properties of water-soluble amphiphilic polymers in presence of double emulsion were studied by diafiltration. Double emulsion systems, water-in-oil-in-water, with a pH gradient between external and internal aqueous phases were prepared. A poly(styrene-co-maleic anhydride) (PSAM) solution at pH 6.0 was added to the external aqueous phase of double emulsion and by application of pressure a divalent metal-ion stream was continuously added. Metal-ions used were Cu(2+) and Cd(2+) at the same pH of polymer solution. According to our results, metal-ion retention is mainly the result of polymer-metal interaction. Interaction between PSMA and reverse emulsion globules is strongly controlled by amount of metal-ions added in the external aqueous phase. In addition, as metal-ion concentration was increased, a negative effect on polymer retention capacity and promotion of flocculation phenomena were produced. Copyright © 2011 Elsevier Inc. All rights reserved.

Characterization of biomass residues and their amendment effects on water sorption and nutrient leaching in sandy soil.

PubMed

Wang, Letian; Tong, Zhaohui; Liu, Guodong; Li, Yuncong

2014-07-01

In this study, we evaluated the efficiency of two types of biomass residues (fermentation residues from a bioethanol process, FB; brown mill residues from a papermaking process, BM) as amendments for a sandy soil. The characteristics of these residues including specific surface areas, morphologies and nutrient sorption capacity were measured. The effects of biorefinery residues on water and nutrient retention were investigated in terms of different particle sizes and loadings. The results indicated that bio-based wastes FB and BM were able to significantly improve water and nutrient retention of sandy soil. The residues with larger surface areas had better water and nutrient retention capability. Specifically, in the addition of 10% loading, FB and BM was able to improve water retention by approximately 150% and 300%, while reduce 99% of ammonium and phosphate concentration in the leachate compare to the soil control, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Neither alpha-blocker therapy nor cystography is required before early catheter removal after radical prostatectomy.

PubMed

Nieder, Alan M; Manoharan, Murugesan; Kim, Sandy S; Soloway, Mark S

2005-02-01

To evaluate the success of early catheter removal from men after radical retropubic prostatectomy (RRP) without using either cystography or giving an alpha-blocker. We retrospectively analysed 156 consecutive patients who had RRPs between June 2003 and May 2004 to determine the incidence of urinary retention after early catheter removal, with no cystogram or using an alpha-blocker. The mean age of the men was 60 years and 99% were clinical stage T1 or T2; 74% had their catheters removed 8 days after RRP. The incidence of urinary retention was 1.3%, and of haematuria requiring catheter replacement 2.6%. Two patients (1.3%) developed a bladder neck contracture. In the present study removing an indwelling catheter 1 week after RRP was safe, with a minimal risk of urinary retention or bladder neck contracture. The addition of an alpha-blocker is unlikely to reduce the already low incidence of urinary retention.

SEM-EDX, water absorption, and wetting capability studies on evaluation of the influence of nano-zinc oxide as additive to paraloid B72 solutions used for wooden artifacts consolidation.

PubMed

Tuduce Traistaru, Ana-Adriana; Crina Anca Sandu, Irina; Cristina Timar, Maria; Lucia Dumitrescu, Georgeta; Sandu, Ion

2013-02-01

Consolidation of frail, degraded wood is a key issue of wooden cultural heritage conservation. Paraloid B72 is one of the most often used consolidant in conservation practice. The present research aimed at formulating stable consolidation solutions of Paraloid B72 with ZnO nano-additives and at determining the influence of these additives on the penetration pathways, retention of the consolidation material into wood and on the water behavior of the treated wood. The experiments were performed on sound samples of aspen (Populus tremula). The addition of nano-ZnO slightly increased the uptake and retention of the consolidant within the wooden structure and led to hydrophobic surfaces. However, the influence of nano-ZnO additives to the water absorption was not conclusive. Scanning Electron Microscope coupled with an EDX Detector investigation proved vessels, fibers, and interconnecting pits as main pathways of consolidant penetration into the wooden structure as well as the presence and distribution of nano-ZnO. Copyright © 2012 Wiley Periodicals, Inc.

The Impact of the Navy’s Tuition Assistance Program on the Retention and Promotion of First-term Sailors

DTIC Science & Technology

2008-06-12

first few months. Hence, much attrition is non-voluntary, and the portion that is voluntary is due to maladjustment to military life. In addition...may view military service as a vehicle for social advancement, and they have a higher propensity for using military benefits. They also may be less...System (ACES) on soldier retention and performance: Data analysis. Alexandria, VA: US Army Research Institute for the Behavioral and Social Sciences

Assessment of Durability of Online and Multisensory Learning Using an Ophthalmology Model.

PubMed

Lippa, Linda Mottow; Anderson, Craig L

2015-10-01

To explore the impact of online learning and multisensory small-group teaching on acquisition and retention of specialty knowledge and diagnostic skills during a third-year family medicine rotation. Exploratory, observational, longitudinal, and multiple-skill measures. Two medical school classes (n = 199) at a public medical school in California. Students engaged in online self-study, small-group interactive diagnostic sessions, picture identification of critical pathologic features, and funduscopic simulator examinations. The authors compared performance on testing immediately after online learning with testing at end-rotation, as well as picture identification versus simulator diagnostic ability in students with (n = 94) and without (n = 105) practice tracing contours on whiteboard projections of those same slides depicting fundus pathologic features of common systemic diseases. Picture identification, accuracy of funduscopic descriptions, online module post-tests, and end-rotation tests. Proprioceptive reinforcement of fundus pattern recognition significantly reduced the need for remediation for misdiagnosing optic disc edema during end-rotation funduscopic simulator testing, but it had no effect on fundus pattern recognition or diagnostic ability overall. Near-perfect immediate online post-test scores contrasted sharply with poor end-rotation scores on an in-house test (average, 59.4%). Rotation timing was not a factor because the patterns remained consistent throughout the academic school year. Neither multisensory teaching nor online self-study significantly improved retention of ophthalmic knowledge and diagnostic skills by the end of a month-long third-year rotation. Timing such training closer to internship when application is imminent may enhance students' appreciation for its value and perhaps may improve retention. Pulsed quizzes over time also may be necessary to motivate students to retain the knowledge gained. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Modeling the Transport of the "New-Horizon" Reduced Graphene Oxide-Metal Oxide Nanohybrids in Water-Saturated Porous Media.

PubMed

Wang, Dengjun; Jin, Yan; Park, Chang Min; Heo, Jiyong; Bai, Xue; Aich, Nirupam; Su, Chunming

2018-04-17

Little is known about the fate and transport of the "new-horizon" multifunctional nanohybrids in the environment. Saturated sand-packed column experiments ( n = 66) were therefore performed to investigate the transport and retention of reduced graphene oxide (RGO)-metal oxide (Fe 3 O 4 , TiO 2 , and ZnO) nanohybrids under environmentally relevant conditions (mono- and divalent electrolytes and natural organic matter). Classical colloid science principles (Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and colloid filtration theory (CFT)) and mathematical models based on the one-dimensional convection-dispersion equation were employed to describe and predict the mobility of RGO-Fe 3 O 4 , RGO-TiO 2 , and RGO-ZnO nanohybrids in porous media. Results indicate that the mobility of the three nanohybrids under varying experimental conditions is overall explainable by DLVO theory and CFT. Numerical simulations suggest that the one-site kinetic retention model (OSKRM) considering both time- and depth-dependent retention accurately approximated the breakthrough curves (BTCs) and retention profiles (RPs) of the nanohybrids concurrently; whereas, others (e.g., two-site retention model) failed to capture the BTCs and/or RPs. This is primarily because blocking BTCs and exponential/hyperexponential/uniform RPs occurred, which is within the framework of OSKRM featuring time- (for kinetic Langmuirian blocking) and depth-dependent (for exponential/hyperexponential/uniform) retention kinetics. Employing fitted parameters (maximum solid-phase retention capacity: S max = 0.0406-3.06 cm 3 /g; and first-order attachment rate coefficient: k a = 0.133-20.6 min -1 ) extracted from the OSKRM and environmentally representative physical variables (flow velocity (0.00441-4.41 cm/min), porosity (0.24-0.54), and grain size (210-810 μm)) as initial input conditions, the long-distance transport scenarios (in 500 cm long sand columns) of the three nanohybrids were predicted via forward simulation. Our findings address the existing knowledge gap regarding the impact of physicochemical factors on the transport of the next-generation, multifunctional RGO-metal oxide nanohybrids in the subsurface.

Portable conduit retention apparatus for releasably retaining a conduit therein

DOEpatents

Metzger, Richard H.

1998-01-01

Portable conduit retention apparatus for releasably retaining a conduit therein. The apparatus releasably retains the conduit out of the way of nearby personnel and equipment. The apparatus includes a portable support frame defining a slot therein having an open mouth portion in communication with the slot for receiving the conduit through the open mouth portion and into the slot. A retention bar is pivotally connected to the support frame adjacent the mouth portion for releasably retaining the conduit in the slot. The retention bar freely pivots to a first position, so that the mouth portion is unblocked in order that the conduit is received through the mouth portion and into the slot. In addition, the retention bar freely pivots to a second position, so that the mouth portion is blocked in order that the conduit is retained in the slot. The conduit is released from the slot by pivoting the retention bar to the first position to unblock the mouth portion and thereafter manipulating the conduit from the slot and through the mouth portion. The apparatus may further include a mounting member attached to the support frame for mounting the apparatus on a vertical support surface. Another embodiment of the apparatus includes a shoe assembly of predetermined weight removably connected to the support frame for resting the apparatus on a floor in such a manner that the apparatus is substantially stationary on the floor.

Effect of maggot (Hermetia illucens) flour in commercial feed on protein retention, energy retention, protein content, and fat content in tilapia (Oreochromis niloticus)

NASA Astrophysics Data System (ADS)

Kurniawan, D. R.; Arief, M.; Agustono; Lamid, M.

2018-04-01

Nile tilapia is a fish with a nature of breeding throughout the year and has a high adaptation. Feed is one of the most important factors that will affect the growth and the sustainability of fish. Maggot is one of the alternative feeds which has function as source of protein.The aim of this research is to ascertain the influence of maggot (Hermetia illucens) flour substitution on commercial feed which affect the retention of energy, retention of protein, and also rough fat and protein of Nile tilapia flesh. The treatment was to substitute the commercial feed with different doses of maggot flour. In this study, the amount of maggot flour substituted on commercial feed is as follows: treatment P0 (0 %), P1 (12 %), P2 (14 %), P3 (16 %) and P4 (18 %). The parameter observed in this study is an effect on to protein retention, energy retention, and also rough fat and protein in Nile tilapia flesh. The result showed the highest protein content was gained from the treatment P4 with 17.267 %. The lowest protein content was 16.344 % obtained in the treatment P0. There was an increasing protein content in Nile tilapia along with the increase of the maggot flour addition in each treatment.

Academic plastic surgery: faculty recruitment and retention.

PubMed

Chen, Jenny T; Girotto, John A; Kitzmiller, W John; Lawrence, W Thomas; Verheyden, Charles N; Vedder, Nicholas B; Coleman, John J; Bentz, Michael L

2014-03-01

A critical element of a thriving academic plastic surgery program is the quality of faculty. A decline in recruitment and retention of faculty has been attributed to the many challenges of academic medicine. Given the substantial resources required to develop faculty, academic plastic surgery has a vested interest in improving the process of faculty recruitment and retention. The American Council of Academic Plastic Surgeons Issues Committee and the American Society of Plastic Surgeons/Plastic Surgery Foundation Academic Affairs Council surveyed the 83 existing programs in academic plastic surgery in February of 2012. The survey addressed the faculty-related issues in academic plastic surgery programs over the past decade. Recruitment and retention strategies were evaluated. This study was designed to elucidate trends, and define best strategies, on a national level. Academic plastic surgery programs have added substantially more full-time faculty over the past decade. Recruitment efforts are multifaceted and can include guaranteed salary support, moving expenses, nurse practitioner/physician's assistant hires, protected time for research, seed funds to start research programs, and more. Retention efforts can include increased compensation, designation of a leadership appointment, protected academic time, and call dilution. Significant change and growth of academic plastic surgery has occurred in the past decade. Effective faculty recruitment and retention are critical to a successful academic center. Funding sources in addition to physician professional fees (institutional program support, grants, contracts, endowment, and so on) are crucial to sustain the academic missions.

Genetic programming based quantitative structure-retention relationships for the prediction of Kovats retention indices.

PubMed

Goel, Purva; Bapat, Sanket; Vyas, Renu; Tambe, Amruta; Tambe, Sanjeev S

2015-11-13

The development of quantitative structure-retention relationships (QSRR) aims at constructing an appropriate linear/nonlinear model for the prediction of the retention behavior (such as Kovats retention index) of a solute on a chromatographic column. Commonly, multi-linear regression and artificial neural networks are used in the QSRR development in the gas chromatography (GC). In this study, an artificial intelligence based data-driven modeling formalism, namely genetic programming (GP), has been introduced for the development of quantitative structure based models predicting Kovats retention indices (KRI). The novelty of the GP formalism is that given an example dataset, it searches and optimizes both the form (structure) and the parameters of an appropriate linear/nonlinear data-fitting model. Thus, it is not necessary to pre-specify the form of the data-fitting model in the GP-based modeling. These models are also less complex, simple to understand, and easy to deploy. The effectiveness of GP in constructing QSRRs has been demonstrated by developing models predicting KRIs of light hydrocarbons (case study-I) and adamantane derivatives (case study-II). In each case study, two-, three- and four-descriptor models have been developed using the KRI data available in the literature. The results of these studies clearly indicate that the GP-based models possess an excellent KRI prediction accuracy and generalization capability. Specifically, the best performing four-descriptor models in both the case studies have yielded high (>0.9) values of the coefficient of determination (R(2)) and low values of root mean squared error (RMSE) and mean absolute percent error (MAPE) for training, test and validation set data. The characteristic feature of this study is that it introduces a practical and an effective GP-based method for developing QSRRs in gas chromatography that can be gainfully utilized for developing other types of data-driven models in chromatography science. Copyright © 2015 Elsevier B.V. All rights reserved.

Nitrogen retention across a gradient of 15N additions to an unpolluted temperate forest soil in Chile

USGS Publications Warehouse

Perakis, Steven S.; Compton, J.E.; Hedin, L.O.

2005-01-01

Accelerated nitrogen (N) inputs can drive nonlinear changes in N cycling, retention, and loss in forest ecosystems. Nitrogen processing in soils is critical to understanding these changes, since soils typically are the largest N sink in forests. To elucidate soil mechanisms that underlie shifts in N cycling across a wide gradient of N supply, we added 15NH415NO3 at nine treatment levels ranging in geometric sequence from 0.2 kg to 640 kg NA? ha-1A? yr-1 to an unpolluted old-growth temperate forest in southern Chile. We recovered roughly half of tracers in 0-25 cm of soil, primarily in the surface 10 cm. Low to moderate rates of N supply failed to stimulate N leaching, which suggests that most unrecovered 15N was transferred from soils to unmeasured sinks above ground. However, soil solution losses of nitrate increased sharply at inputs > 160 kg NA? ha-1A? yr-1, corresponding to a threshold of elevated soil N availability and declining 15N retention in soil. Soil organic matter (15N in soils at the highest N inputs and may explain a substantial fraction of the 'missing N' often reported in studies of fates of N inputs to forests. Contrary to expectations, N additions did not stimulate gross N cycling, potential nitrification, or ammonium oxidizer populations. Our results indicate that the nonlinearity in N retention and loss resulted directly from excessive N supply relative to sinks, independent of plant-soil-microbial feedbacks. However, N additions did induce a sharp decrease in microbial biomass C:N that is predicted by N saturation theory, and which could increase long-term N storage in soil organic matter by lowering the critical C:N ratio for net N mineralization. All measured sinks accumulated 15N tracers across the full gradient of N supply, suggesting that short-term nonlinearity in N retention resulted from saturation of uptake kinetics, not uptake capacity, in plant, soil, and microbial pools.

Urea recycling contributes to nitrogen retention in calves fed milk replacer and low-protein solid feed.

PubMed

Berends, Harma; van den Borne, Joost J G C; Røjen, Betina A; van Baal, Jürgen; Gerrits, Walter J J

2014-07-01

Urea recycling, with urea originating from catabolism of amino acids and hepatic detoxification of ammonia, is particularly relevant for ruminant animals, in which microbial protein contributes substantially to the metabolizable protein supply. However, the quantitative contribution of urea recycling to protein anabolism in calves during the transition from preruminants (milk-fed calves) to ruminants [solid feed (SF)-fed calves] is unknown. The aim of this study was to quantify urea recycling in milk-fed calves when provided with low-protein SF. Forty-eight calves [164 ± 1.6 kg body weight (BW)] were assigned to 1 of 4 SF levels [0, 9, 18, and 27 g of dry matter (DM) SF · kg BW(-0.75) · d⁻¹] provided in addition to an identical amount of milk replacer. Urea recycling was quantified after a 24-h intravenous infusion of [¹⁵N₂]urea by analyzing urea isotopomers in 68-h fecal and urinary collections. Real-time qPCR was used to measure gene expression levels of bovine urea transporter B (bUTB) and aquaglyceroporin-3 and aquaglyceroporin-7 in rumen wall tissues. For every incremental gram of DM SF intake (g DM · kg(0.75)), nitrogen intake increased by 0.70 g, and nitrogen retention increased by 0.55 g (P < 0.01). Of this increase in nitrogen retention, 19% could be directly explained by urea recycling. Additionally, part of the observed increase in nitrogen retention could be explained by the extra protein provided by the SF and likely by a greater efficiency of postabsorptive use of nitrogen for gain. Ruminal bUTB abundance increased (P < 0.01) with SF provision. Aquaglyceroporin-3 expression increased (P < 0.01) with SF intake, but aquaglyceroporin-7 expression did not. We conclude that in addition to the increase in digested nitrogen, urea recycling contributes to the observed increase in nitrogen retention with increasing SF intake in milk-fed calves. Furthermore, ruminal bUTB and aquaglyceroporin-3 expression are upregulated with SF intake, which might be associated with urea recycling. © 2014 American Society for Nutrition.

Student Mental Models of the Greenhouse Effect: Retention Months After Interventions

NASA Astrophysics Data System (ADS)

Harris, S. E.; Gold, A. U.

2013-12-01

Individual understanding of climate science, and the greenhouse effect in particular, is one factor important for societal decision-making. Ideally, learning opportunities about the greenhouse effect will not only move people toward expert-like ideas but will also have long-lasting effects for those individuals. We assessed university students' mental models of the greenhouse effect before and after specific learning experiences, on a final exam, then again a few months later. Our aim was to measure retention after students had not necessarily been thinking about, nor studying, the greenhouse effect recently. How sticky were the ideas learned? 164 students in an introductory science course participated in a sequence of two learning activities and assessments regarding the greenhouse effect. The first lesson involved the full class, then, for the second lesson, half the students completed a simulation-based activity and the other half completed a data-driven activity. We assessed student thinking through concept sketches, multiple choice and short answer questions. All students generated concept sketches four times, and completed a set of multiple choice (MCQs) and short answer questions twice. Later, 3-4 months after the course ended, 27 students ('retention students') completed an additional concept sketch and answered the questions again, as a retention assessment. These 27 students were nearly evenly split between the two contrasting second lessons in the sequence and included both high and low-achieving students. We then compared student sketches and scores to 'expert' answers. The general pattern over time showed a significant increase in student scores from before the lesson sequence to after, both on concept sketches and MCQs, then an additional increase in concept sketch score on the final exam (MCQs were not asked on the final exam). The scores for the retention students were not significantly different from the full class. Within the retention group, there was also no difference in scores based on which contrasting lesson a student did. Students in both of the contrasting lessons scored significantly higher on the retention test than on the initial pre-test. Their concept sketch scores on the retention test were slightly lower than their scores on the final exam (not significantly), but matched their post-lesson-sequence scores. Their MCQ scores were slightly higher on the retention test than on the post-lesson-sequence test (also not significantly). These results imply that students both learned and retained new ideas about the greenhouse effect for at least a few months after the end of the course and did not regress to their pre-lesson ideas. Further analysis should show which particular aspects of student mental models changed over the full temporal sequence.

Internal dispersal of seeds by waterfowl: effect of seed size on gut passage time and germination patterns

NASA Astrophysics Data System (ADS)

Figuerola, Jordi; Charalambidou, Iris; Santamaria, Luis; Green, Andy J.

2010-06-01

Long distance dispersal may have important consequences for gene flow and community structure. The dispersal of many plants depends on transport by vertebrate seed dispersers. The shapes of seed shadows produced by vertebrates depend both on movement patterns of the dispersers and on the dynamics and effects of passage through the disperser’s gut (i.e. the retention time, survival and germination of ingested seeds). A combination of experiments with captive waterbirds and aquatic plant seeds was used to analyse the following: (a) the effects of inter- and intra-specific variation in seed size and duck species on seed retention time in the gut and (b) the relationship between retention time and the percent germination and germination rates of seeds. Among the three Scirpus species used, those with smaller seeds showed higher survival after ingestion by birds and longer retention times inside their guts than those with larger seeds. For Potamogeton pectinatus, only seeds from the smaller size class (<8 mg) survived ingestion. Retention time affected the percent germination and germination rate of Scirpus seeds but in a manner that varied for the different plant and bird species studied. We recorded both linear and non-linear effects of retention time on percent germination. In addition, germination rate was positively correlated with retention time in Scirpus litoralis but negatively correlated in Scirpus lacustris. Small seed size can favour dispersal over larger distances. However, the effects of retention time on percent germination can modify the seed shadows produced by birds due to higher percent germination of seeds retained for short or intermediate periods. The changes in dispersal quality associated with dispersal distance (which is expected to be positively related to retention time) will affect the probability of seedling establishment over longer distances and, thus, the spatial characteristics of the effective seed shadow.

Retention among North American HIV-infected persons in clinical care, 2000-2008.

PubMed

Rebeiro, Peter; Althoff, Keri N; Buchacz, Kate; Gill, John; Horberg, Michael; Krentz, Hartmut; Moore, Richard; Sterling, Timothy R; Brooks, John T; Gebo, Kelly A; Hogg, Robert; Klein, Marina; Martin, Jeffrey; Mugavero, Michael; Rourke, Sean; Silverberg, Michael J; Thorne, Jennifer; Gange, Stephen J

2013-03-01

Retention in care is key to improving HIV outcomes. The goal of this study was to describe 'churn' in patterns of entry, exit, and retention in HIV care in the United States and Canada. Adults contributing ≥1 CD4 count or HIV-1 RNA (HIV-lab) from 2000 to 2008 in North American AIDS Cohort Collaboration on Research and Design clinical cohorts were included. Incomplete retention was defined as lack of 2 HIV-laboratories (≥90 days apart) within 12 months, summarized by calendar year. Beta-binomial regression models were used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) of factors associated with incomplete retention. Among 61,438 participants, 15,360 (25%) with incomplete retention significantly differed in univariate analyses (P < 0.001) from 46,078 (75%) consistently retained by age, race/ethnicity, HIV risk, CD4, antiretroviral therapy use, and country of care (United States vs. Canada). From 2000 to 2004, females (OR = 0.82, CI: 0.70 to 0.95), older individuals (OR = 0.78, CI: 0.74 to 0.83 per 10 years), and antiretroviral therapy users (OR = 0.61, CI: 0.54 to 0.68 vs. all others) were less likely to have incomplete retention, whereas black individuals (OR = 1.31, CI: 1.16 to 1.49, vs. white), those with injection drug use HIV risk (OR = 1.68, CI: 1.49 to 1.89, vs. noninjection drug use), and those in care longer (OR = 1.09, CI: 1.07 to 1.11 per year) were more likely to have incomplete retention. Results from 2005 to 2008 were similar. From 2000 to 2008, 75% of the North American AIDS Cohort Collaboration on Research and Design population was consistently retained in care with 25% experiencing some changes in status or churn. In addition to the programmatic and policy implications, the findings of this study identify patient groups who may benefit from focused retention efforts.

Retention Among North American HIV–infected Persons in Clinical Care, 2000–2008

PubMed Central

Rebeiro, Peter; Althoff, Keri N.; Buchacz, Kate; Gill, M. John; Horberg, Michael; Krentz, Hartmut; Moore, Richard; Sterling, Timothy R.; Brooks, John T.; Gebo, Kelly A.; Hogg, Robert; Klein, Marina; Martin, Jeffrey; Mugavero, Michael; Rourke, Sean; Silverberg, Michael J.; Thorne, Jennifer; Gange, Stephen J.

2013-01-01

Background Retention in care is key to improving HIV outcomes. Our goal was to describe “churn” in patterns of entry, exit, and retention in HIV care in the US and Canada. Methods Adults contributing ≥1 CD4 count or HIV-1 RNA (HIV-lab) from 2000–2008 in North American Cohort Collaboration on Research and Design (NA-ACCORD) clinical cohorts were included. Incomplete retention was defined as lack of 2 HIV-labs (≥90 days apart) within 12 months, summarized by calendar year. We used beta-binomial regression models to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI) of factors associated with incomplete retention. Results Among 61,438 participants, 15,360 (25%) with incomplete retention significantly differed in univariate analyses (p<0.001) from 46,078 (75%) consistently retained by age, race/ethnicity, HIV risk, CD4, ART use, and country of care (US vs. Canada). From 2000–2004, females (OR=0.82, CI:0.70–0.95), older individuals (OR=0.78, CI:0.74–0.83 per 10 years), and ART users (OR= 0.61, CI:0.54–0.68 vs all others) were less likely to have incomplete retention, while black individuals (OR=1.31, CI:1.16–1.49, vs. white), those with injection drug use (IDU) HIV risk (OR=1.68, CI:1.49–1.89, vs. non-IDU) and those in care longer (OR=1.09, CI:1.07–1.11 per year) were more likely to have incomplete retention. Results from 2005–2008 were similar. Discussion From 2000 to 2008, 75% of the NA-ACCORD population was consistently retained in care with 25% experiencing some change in status, or churn. In addition to the programmatic and policy implications, our findings identify patient groups who may benefit from focused retention efforts. PMID:23242158

Factors in Human-Computer Interface Design (A Pilot Study).

DTIC Science & Technology

1994-12-01

This study used a pretest - posttest control group experimental design to test the effect of consistency on speed, retention, and user satisfaction. Four...analysis. The overall methodology was a pretest - posttest control group experimental design using different prototypes to test the effects of...methodology used for this study was a pretest - posttest control group experimental design using different prototypes to test for features of the human

A Science Summer Camp as an Effective Way to Recruit High School Students to Major in the Physical Sciences and Science Education

ERIC Educational Resources Information Center

Bischoff, Paul J.; Castendyk, Devin; Gallagher, Hugh; Schaumloffel, John; Labroo, Sunil

2008-01-01

Now in its fifth year, PR[superscript 2]EPS is a National Science Foundation funded initiative designed to recruit high school students to attend college majoring in the physical sciences, including engineering and secondary science education, and to help ensure their retention within these programs until graduation. A central feature of the…

LC-MSsim – a simulation software for liquid chromatography mass spectrometry data

PubMed Central

Schulz-Trieglaff, Ole; Pfeifer, Nico; Gröpl, Clemens; Kohlbacher, Oliver; Reinert, Knut

2008-01-01

Background Mass Spectrometry coupled to Liquid Chromatography (LC-MS) is commonly used to analyze the protein content of biological samples in large scale studies. The data resulting from an LC-MS experiment is huge, highly complex and noisy. Accordingly, it has sparked new developments in Bioinformatics, especially in the fields of algorithm development, statistics and software engineering. In a quantitative label-free mass spectrometry experiment, crucial steps are the detection of peptide features in the mass spectra and the alignment of samples by correcting for shifts in retention time. At the moment, it is difficult to compare the plethora of algorithms for these tasks. So far, curated benchmark data exists only for peptide identification algorithms but no data that represents a ground truth for the evaluation of feature detection, alignment and filtering algorithms. Results We present LC-MSsim, a simulation software for LC-ESI-MS experiments. It simulates ESI spectra on the MS level. It reads a list of proteins from a FASTA file and digests the protein mixture using a user-defined enzyme. The software creates an LC-MS data set using a predictor for the retention time of the peptides and a model for peak shapes and elution profiles of the mass spectral peaks. Our software also offers the possibility to add contaminants, to change the background noise level and includes a model for the detectability of peptides in mass spectra. After the simulation, LC-MSsim writes the simulated data to mzData, a public XML format. The software also stores the positions (monoisotopic m/z and retention time) and ion counts of the simulated ions in separate files. Conclusion LC-MSsim generates simulated LC-MS data sets and incorporates models for peak shapes and contaminations. Algorithm developers can match the results of feature detection and alignment algorithms against the simulated ion lists and meaningful error rates can be computed. We anticipate that LC-MSsim will be useful to the wider community to perform benchmark studies and comparisons between computational tools. PMID:18842122

[Prostatic localization revealing an acute myeloid leukemia. Apropos of a case].

PubMed

Smaoui, S; Lecomte, M J; Peraldi, R; Pernin, F

1998-09-01

The authors report an original case of acute myeloid leukaemia (AML) presenting in the form of acute urinary retention, confirmed by prostatic biopsy, with complete absence of any non-urological clinical features. Prostatic sites of leukaemia are frequent and classically reported, but often occur during the course of known leukaemia, and are rarely symptomatic, justifying biopsies in the presence of any prostatic symptoms. Immunolabelling represents the key to the diagnosis in the presence of undifferentiated cells demonstrated on prostatic biopsies. The outcome was fatal in this case, despite early chemotherapy. The clinical features, clinical course and therapeutic aspects of prostatic leukaemia are discussed.

[Factors influencing bonding fixed restorations].

PubMed

Medić, Vesna; Obradović-Djuricić, Kosovka

2008-01-01

Crown displacement often occurs because the features of tooth preparations do not counteract the forces directed against restorations. The purpose of this study was to evaluate the effect of preparation designs on retention and resistance of fixed restorations. The study was performed on 64 differently sized stainless steel dies. Also, caps which were used for evaluated retention were made of stainless steel for each die. After cementing the caps on experimental dies, measuring of necessary tensile forces to separate cemented caps from dies was done. Caps, which were made of a silver-palladium alloy with a slope of 600 to the longitudinal axis formed on the occlusal surface, were used for evaluating resistance. A sudden drop in load pressure recorded by the test machine indicated failure for that cap. A significant difference was found between the tensile force required to remove the caps from the dies with different length (p < 0.05) and different taper (p < 0.01). The greatest retentive strengths (2579.2 N and 2989.8 N) were noticed in experimental dies with the greatest length and smallest taper. No statistically significant (p > 0.05) differences were found between tensile loads for caps cemented on dies with different diameter. Although there was an apparent slight increase in resistance values for caps on dies with smaller tapers, the increase in resistance for those preparation designs was not statistically significant. There was a significant difference among the resistance values for caps on dies with different length (p < 0.01) and diameter (p < 0.05). In the light of the results obtained, it could be reasonably concluded that retention and resistance of the restoration is in inverse proportion to convergence angle of the prepared teeth. But, at a constant convergence angle, retention and resistance increase with rising length and diameter.

Molecular dynamics modeling framework for overcoming nanoshape retention limits of imprint lithography

NASA Astrophysics Data System (ADS)

Cherala, Anshuman; Sreenivasan, S. V.

2018-12-01

Complex nanoshaped structures (nanoshape structures here are defined as shapes enabled by sharp corners with radius of curvature <5 nm) have been shown to enable emerging nanoscale applications in energy, electronics, optics, and medicine. This nanoshaped fabrication at high throughput is well beyond the capabilities of advanced optical lithography. While the highest-resolution e-beam processes (Gaussian beam tools with non-chemically amplified resists) can achieve <5 nm resolution, this is only available at very low throughputs. Large-area e-beam processes, needed for photomasks and imprint templates, are limited to 18 nm half-pitch lines and spaces and 20 nm half-pitch hole patterns. Using nanoimprint lithography, we have previously demonstrated the ability to fabricate precise diamond-like nanoshapes with 3 nm radius corners over large areas. An exemplary shaped silicon nanowire ultracapacitor device was fabricated with these nanoshaped structures, wherein the half-pitch was 100 nm. The device significantly exceeded standard nanowire capacitor performance (by 90%) due to relative increase in surface area per unit projected area, enabled by the nanoshape. Going beyond the previous work, in this paper we explore the scaling of these nanoshaped structures to 10 nm half-pitch and below. At these scales a new "shape retention" resolution limit is observed due to polymer relaxation in imprint resists, which cannot be predicted with a linear elastic continuum model. An all-atom molecular dynamics model of the nanoshape structure was developed here to study this shape retention phenomenon and accurately predict the polymer relaxation. The atomistic framework is an essential modeling and design tool to extend the capability of imprint lithography to sub-10 nm nanoshapes. This framework has been used here to propose process refinements that maximize shape retention, and design template assist features (design for nanoshape retention) to achieve targeted nanoshapes.

Retention of mandibular advancement devices in the treatment of obstructive sleep apnea: an in vitro pilot study.

PubMed

Vanderveken, Olivier M; Van de Heyning, Paul; Braem, Marc J

2014-05-01

In order for a mandibular advancement device (MAD) to be efficacious, it must remain seated on the teeth during sleep. Quantitative data on the retentive characteristics of MADs are currently unavailable. The present pilot study is the first to describe an in vitro setup testing the retentive characteristics of different monobloc MADs. A hydraulic cyclic test machine was used with MADs seated on dental casts to measure retention forces upon removal of the MADs. A custom-made monobloc (CM-mono), a thermoplastic monobloc (TP-mono), and a thermoplastic duobloc (TP-duo) configured as a monobloc were tested. Two protrusions were investigated, representing 25 and 65% of the maximal protrusion. The effects of the type of MAD, duration of the test, and amount of protrusion on removal forces were measured. The measured removal forces of all three MADs tested differed significantly, with the TP-duo showing the highest values (P < 0.0001). The effects of wear due to the repetitive cyclic loading became obvious by the production of wear particles in all MADs tested. However, only the TP-duo showed a significant reduction in time in removal forces for both protrusion positions (P < 0.0001; P = 0.0011). The effect of the amount of protrusion on the removal forces differed significantly between all three MADs tested (P = 0.0074). This in vitro pilot study reveals significant differences in retention forces for the MADs tested. The findings are consistent with clinical effects of nightly loss of MADs as reported in the literature and are within the range of reported physiological mouth-opening forces. Future research is needed to determine the key design features of MADs that explain these differences.

Enhanced methodology for porting ion chromatography retention data.

PubMed

Park, Soo Hyun; Shellie, Robert A; Dicinoski, Greg W; Schuster, Georg; Talebi, Mohammad; Haddad, Paul R; Szucs, Roman; Dolan, John W; Pohl, Christopher A

2016-03-04

Porting is a powerful methodology to recalibrate an existing database of ion chromatography (IC) retention times by reflecting the changes of column behavior resulting from either batch-to-batch variability in the production of the column or the manufacture of new versions of a column. This approach has been employed to update extensive databases of retention data of inorganic and organic anions forming part of the "Virtual Column" software marketed by Thermo Fisher Scientific, which is the only available commercial optimization tool for IC separation. The current porting process is accomplished by performing three isocratic separations with two representative analyte ions in order to derive a porting equation which expresses the relationship between old and new data. Although the accuracy of retention prediction is generally enhanced on new columns, errors were observed on some columns. In this work, the porting methodology was modified in order to address this issue, where the porting equation is now derived by using six representative analyte ions (chloride, bromide, iodide, perchlorate, sulfate, and thiosulfate). Additionally, the updated porting methodology has been applied on three Thermo Fisher Scientific columns (AS20, AS19, and AS11HC). The proposed approach showed that the new porting methodology can provide more accurate and robust retention prediction on a wide range of columns, where average errors in retention times for ten test anions under three eluent conditions were less than 1.5%. Moreover, the retention prediction using this new approach provided an acceptable level of accuracy on a used column exhibiting changes in ion-exchange capacity. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Improving Participants' Retention in a Smoking Cessation Intervention Using a Community-based Participatory Research Approach.

PubMed

Estreet, Anthony; Apata, Jummai; Kamangar, Farin; Schutzman, Christine; Buccheri, Jane; O'Keefe, Anne-Marie; Wagner, Fernando; Sheikhattari, Payam

2017-01-01

This study compares participant' sretention in three phases of smoking cessation interventions, one provided in a health clinic and the subsequent two in community-based settings. Smoking cessation interventions were conducted in three phases from 2008 to 2015 in two underserved urban communities with low socioeconomic profiles and high rates of smoking ( n = 951). Phase I was conducted in a clinic; Phases II and III were conducted in community venues. In Phases II and III, incremental changes were made based on lessons learned from the previous phases. Retention (attending six or more sessions) was the primary predictor of cessation and was analyzed while controlling for associated factors including age, gender, race, employment, education, and nicotine dependence. Retention increased substantially over the three phases, with rates for attending six or more sessions of 13.8%, 51.9%, and 67.9% in Phases I, II, and III, respectively. Retention was significantly higher in community settings than in the clinic setting (adjusted odds ratio [OR] = 6.7; 95% confidence intervals [CI] = 4.6, 9.8). In addition to the intervention in community venues, predictors of retention included age and unemployment. Higher retention was significantly associated with higher quit rates (adjusted OR = 2.4; 95% CI = 1.5, 3.8). Conducting the intervention in community settings using trained peer motivators rather than health-care providers resulted in significantly higher retention and smoking cessation rates. This was due in part to the ability to tailor cessation classes in the community for specific populations and improving the quality of the intervention based on feedback from participants and community partners.

Temporal patterns of apparent leg band retention in North American geese

USGS Publications Warehouse

Zimmerman, Guthrie S.; Kendall, William L.; Moser, Timothy J.; White, Gary C.; Doherty, Paul F.

2009-01-01

An important assumption of mark?recapture studies is that individuals retain their marks, which has not been assessed for goose reward bands. We estimated aluminum leg band retention probabilities and modeled how band retention varied with band type (standard vs. reward band), band age (1-40 months), and goose characteristics (species and size class) for Canada (Branta canadensis), cackling (Branta hutchinsii), snow (Chen caerulescens), and Ross?s (Chen rossii) geese that field coordinators double-leg banded during a North American goose reward band study (N = 40,999 individuals from 15 populations). We conditioned all models in this analysis on geese that were encountered with >1 leg band still attached (n = 5,747 dead recoveries and live recaptures). Retention probabilities for standard aluminum leg bands were high (estimate of 0.9995, SE = 0.001) and constant over 1-40 months. In contrast, apparent retention probabilities for reward bands demonstrated an interactive relationship between 5 size and species classes (small cackling, medium Canada, large Canada, snow, and Ross?s geese). In addition, apparent retention probabilities for each of the 5 classes varied quadratically with time, being lower immediately after banding and at older age classes. The differential retention probabilities among band type (reward vs. standard) that we observed suggests that 1) models estimating reporting probability should incorporate differential band loss if it is nontrivial, 2) goose managers should consider the costs and benefits of double-banding geese on an operational basis, and 3) the United States Geological Survey Bird Banding Lab should modify protocols for receiving recovery data.

Turning Points: Improving Honors Student Preparation for Thesis Completion

ERIC Educational Resources Information Center

Patino, Cynthia

2012-01-01

This dissertation is an action research study that had as its primary goal to increase retention of honors college students at Arizona State University by implementing an additional advising session during the fifth semester of their academic career. Introducing additional, strategically-timed support for the honors thesis and demystifying the…

Chætognath transcriptome reveals ancestral and unique features among bilaterians

PubMed Central

Marlétaz, Ferdinand; Gilles, André; Caubit, Xavier; Perez, Yvan; Dossat, Carole; Samain, Sylvie; Gyapay, Gabor; Wincker, Patrick; Le Parco, Yannick

2008-01-01

Background The chætognaths (arrow worms) have puzzled zoologists for years because of their astonishing morphological and developmental characteristics. Despite their deuterostome-like development, phylogenomic studies recently positioned the chætognath phylum in protostomes, most likely in an early branching. This key phylogenetic position and the peculiar characteristics of chætognaths prompted further investigation of their genomic features. Results Transcriptomic and genomic data were collected from the chætognath Spadella cephaloptera through the sequencing of expressed sequence tags and genomic bacterial artificial chromosome clones. Transcript comparisons at various taxonomic scales emphasized the conservation of a core gene set and phylogenomic analysis confirmed the basal position of chætognaths among protostomes. A detailed survey of transcript diversity and individual genotyping revealed a past genome duplication event in the chætognath lineage, which was, surprisingly, followed by a high retention rate of duplicated genes. Moreover, striking genetic heterogeneity was detected within the sampled population at the nuclear and mitochondrial levels but cannot be explained by cryptic speciation. Finally, we found evidence for trans-splicing maturation of transcripts through splice-leader addition in the chætognath phylum and we further report that this processing is associated with operonic transcription. Conclusion These findings reveal both shared ancestral and unique derived characteristics of the chætognath genome, which suggests that this genome is likely the product of a very original evolutionary history. These features promote chætognaths as a pivotal model for comparative genomics, which could provide new clues for the investigation of the evolution of animal genomes. PMID:18533022

Neuropsychological tests for predicting cognitive decline in older adults

PubMed Central

Baerresen, Kimberly M; Miller, Karen J; Hanson, Eric R; Miller, Justin S; Dye, Richelin V; Hartman, Richard E; Vermeersch, David; Small, Gary W

2015-01-01

Summary Aim To determine neuropsychological tests likely to predict cognitive decline. Methods A sample of nonconverters (n = 106) was compared with those who declined in cognitive status (n = 24). Significant univariate logistic regression prediction models were used to create multivariate logistic regression models to predict decline based on initial neuropsychological testing. Results Rey–Osterrieth Complex Figure Test (RCFT) Retention predicted conversion to mild cognitive impairment (MCI) while baseline Buschke Delay predicted conversion to Alzheimer’s disease (AD). Due to group sample size differences, additional analyses were conducted using a subsample of demographically matched nonconverters. Analyses indicated RCFT Retention predicted conversion to MCI and AD, and Buschke Delay predicted conversion to AD. Conclusion Results suggest RCFT Retention and Buschke Delay may be useful in predicting cognitive decline. PMID:26107318

Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement

NASA Astrophysics Data System (ADS)

Akhlaghi, Omid; Menceloglu, Yusuf Ziya; Akbulut, Ozge

2017-01-01

Calcium aluminate cement (CAC) suffers from loss of workability in less than an hour (~15 minutes) after first touch of water. Current superplasticizers that are utilized to modify the viscosity of cement admixtures are designed to target ordinary Portland cement (OPC). The high affinity between these superplasticizers and cement particles were found to be detrimental in CAC systems. Utilization of a monomer that, instead, facilitates gradual adsorption of a superplasticizer provides workability retention. For the first time in literature, we report a superplasticizer that caters to the properties of CAC such as high rate of surface development and surface charge. While neat CAC was almost unworkable after 1 hour, with the addition of only 0.4% of the optimized superplasticizer, 90% fluidity retention was achieved.

Cauliflower-derived porous carbon without activation for electrochemical capacitor and CO2 capture applications

NASA Astrophysics Data System (ADS)

Du, Juan; Yu, Yifeng; Lv, Haijun; Chen, Chunlin; Zhang, Jian; Chen, Aibing

2018-01-01

Carbon materials have attracted great attention in CO2 capture and energy storage due to their excellent characteristics such as tunable pore structure, modulated surface properties and superior bulk conductivities, etc. Biomass, provided by nature with non-toxic, widespread, abundant, and sustainable advantages, is considered to be a very promising precursor of carbons for the view of economic, environmental, and societal issues. However, the preparation of high-performance biomass-derived carbons is still a big challenge because of the multistep process for their synthesis and subsequent activation. Herein, hierarchically porous structured carbon materials have been prepared by directly carbonizing dried cauliflowers without any addition of agents and activation process, featuring with large specific surface area, hierarchically porous structure and improved pore volume, as well as suitable nitrogen content. Being used as a solid-state CO2 adsorbent, the obtained product exhibited a high CO2 adsorption capacity of 3.1 mmol g-1 under 1 bar and 25 °C and a remarkable reusability of 96.7% retention after 20 adsorption/regeneration cycles. Our study reveals that choosing a good biomass source was significant as the unique structure of precursor endows the carbonized product with abundant pores without the need of any post-treatment. Used as an electrode material in electrochemical capacitor, the non-activated porous carbon displayed a fairly high specific capacitance of 228.9 F g-1 at 0.5 A g-1 and an outstanding stability of 99.2% retention after 5000 cycles at 5 A g-1. [Figure not available: see fulltext.

Kinetics of Molybdenum Adsorption and Desorption in Soils.

PubMed

Sun, Wenguang; Selim, H Magdi

2018-05-01

Much uncertainty exists in mechanisms and kinetics controlling the adsorption and desorption of molybdenum (Mo) in the soil environment. To investigate the characteristics of Mo adsorption and desorption and predict Mo behavior in the vadose zone, kinetic batch experiments were performed using three soils: Webster loam, Windsor sand and Mahan sand. Adsorption isotherms for Mo were strongly nonlinear for all three soils. Strong kinetic adsorption of Mo by all soils was also observed, where the rate of retention was rapid initially and was followed by slow retention behavior with time. The time-dependent Mo sorption rate was not influenced when constant pH was maintained. Desorption or release results indicated that there were significant fractions of Mo that appeared to be irreversible or slowly reversibly sorbed by Windsor and Mahan. X-ray absorption near edge structure (XANES) analysis for Windsor and Mahan soils indicated that most of Mo had been bound to kaolinite, whereas Webster had similar XANES features to those of Mo sorbed to montmorillonite. A sequential extraction procedure provided evidence that a significant amount of Mo was irreversibly sorbed. A multireaction model (MRM) with nonlinear equilibrium and kinetic sorption parameters was used to describe the adsorption-desorption kinetics of Mo on soils. Our results demonstrated that a formulation of MRM with two sorption sites (equilibrium and reversible) successfully described Mo adsorption-desorption data for Webster loam, and an additional irreversible reaction phase was recommended to describe Mo desorption or release with time for Windsor and Mahan soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Exploring the Limits for Reduction of Plastid Genomes: A Case Study of the Mycoheterotrophic Orchids Epipogium aphyllum and Epipogium roseum

PubMed Central

Schelkunov, Mikhail I.; Shtratnikova, Viktoria Yu; Nuraliev, Maxim S.; Selosse, Marc-Andre; Penin, Aleksey A.; Logacheva, Maria D.

2015-01-01

The question on the patterns and limits of reduction of plastid genomes in nonphotosynthetic plants and the reasons of their conservation is one of the intriguing topics in plant genome evolution. Here, we report sequencing and analysis of plastid genome in nonphotosynthetic orchids Epipogium aphyllum and Epipogium roseum, which, with sizes of 31 and 19 kbp, respectively, represent the smallest plastid genomes characterized by now. Besides drastic reduction, which is expected, we found several unusual features of these “minimal” plastomes: Multiple rearrangements, highly biased nucleotide composition, and unprecedentedly high substitution rate. Only 27 and 29 genes remained intact in the plastomes of E. aphyllum and E. roseum—those encoding ribosomal components, transfer RNAs, and three additional housekeeping genes (infA, clpP, and accD). We found no signs of relaxed selection acting on these genes. We hypothesize that the main reason for retention of plastid genomes in Epipogium is the necessity to translate messenger RNAs (mRNAs) of accD and/or clpP proteins which are essential for cell metabolism. However, these genes are absent in plastomes of several plant species; their absence is compensated by the presence of a functional copy arisen by gene transfer from plastid to the nuclear genome. This suggests that there is no single set of plastid-encoded essential genes, but rather different sets for different species and that the retention of a gene in the plastome depends on the interaction between the nucleus and plastids. PMID:25635040

Effect of chelators on functionality of milk protein concentrates obtained by ultrafiltration at a constant pH and temperature.

PubMed

Ramchandran, Lata; Luo, XiaoXia; Vasiljevic, Todor

2017-11-01

Modulating conditions during ultrafiltration of skim milk appears to be a feasible strategy to obtain milk protein concentrates (MPC) with tailored functionalities. Adjustment of pH and process temperature attenuated properties of casein micelle resulting in enhanced emulsification capacity. Additional pre-treatment options such as addition of calcium chelators can further impact on the functionality of MPC by modifying the calcium distribution and casein micelle integrity. The objective of the project was to establish effects of pre-treating skim milk with calcium chelators (EDTA or citrate) in concentrations between 10 to 30 mm prior to UF on the physical properties of the feed, corresponding retentates and dried MPC, including particle size, zeta potential and calcium distribution in skim milk and the corresponding retentates, as well as the physical functionalities such as solubility, heat stability and emulsifying properties. Addition of calcium chelators (EDTA or citrate), at levels 20-30 mm concentrations reduced casein micelle size as well as total, soluble and ionic calcium contents that resulted in MPC with enhanced solubility and heat stability. The emulsion capacity was, however, improved only with EDTA at 10 mm concentration. The enhanced functionality is attributed to the reduced particle size resulting from the removal of calcium from the retentate that could modify micellar casein to an extent sufficient to cause such improvements.

Effects of blanching, acidification, or addition of EDTA on vitamin C and β-carotene stability during mango purée preparation.

PubMed

Guiamba, Isabel R F; Svanberg, Ulf

2016-09-01

The impact of acidification with citric acid, addition of EDTA or water blanching at high temperature, and short time (HTST) conducted at 90°C for 4 min, on the retention of vitamin C (L-AA and DHAA) and β-carotene was studied in mango purée 30 min after crushing. HTST blanching prior to matrix disruption into purée resulted in complete inactivation of polyphenol oxidase (PPO) and minor residual activity (8%) of ascorbic acid oxidase (AAO). The retention of total vitamin C was 100% in blanched purées and in purée with EDTA and about 90% in purées at pH 3.9 and 5.0. Acidification, blanching, and addition of EDTA preserved vitamin C mainly as L-AA, while complete conversion into DHAA was observed in purée at pH 5.0. The retention of all-trans-β-carotene was between 65 and 72%, with the highest value in purée with EDTA and the lowest value in purée of blanched mango. The ratio of 13-cis-β-carotene in fresh mango was 8.2 ± 0.5% that increased significantly after blanching and in purée at pH 5.0.

Enantiomeric separation of 2-arylpropionic acid nonsteroidal anti-inflammatory drugs by HPLC with hydroxypropyl-beta-cyclodextrin as chiral mobile phase additive.

PubMed

Ye, Jincui; Yu, Wenying; Chen, Guosheng; Shen, Zhengrong; Zeng, Su

2010-08-01

The enantio-separations of eight 2-arylpropionic acid nonsteroidal anti-inflammatory drugs (2-APA NSAIDs) were established using reversed-phase high-performance liquid chromatography with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as chiral mobile phase additive for studying the stereoselective skin permeation of suprofen, ketoprofen, naproxen, indoprofen, fenoprofen, furbiprofen, ibuprofen and carprofen. The effects of the mobile phase composition, concentration of HP-beta-CD and column temperature on retention and enantioselective separation were investigated. With 2-APA NSAIDs as acidic analytes, the retention times and resolutions of the enantiomers were strongly related to the pH of the mobile phase. In addition, both the concentration of HP-beta-CD and temperature had a great effect on retention time, but only a slight or almost no effect on resolutions of the analytes. Enantioseparations were achieved on a Shimpack CLC-ODS (150 x 4.6 mm i.d., 5 microm) column. The mobile phase was a mixture of methanol and phosphate buffer (pH 4.0-5.5, 20 mM) containing 25 mM HP-beta-CD. This method was flexible, simple and economically advantageous over the use of chiral stationary phase, and was successfully applied to the enantioselective determination of the racemic 2-APA NSAIDs in an enantioselective skin permeation study.

Additive benefits of autonomy support and enhanced expectancies for motor learning.

PubMed

Wulf, Gabriele; Chiviacowsky, Suzete; Cardozo, Priscila Lopes

2014-10-01

Two factors that have been shown to facilitate motor learning are autonomy support (AS) and enhanced expectancies (EE) for performance. We examined the individual and combined influences of these factors. In a 2 × 2 design, participants learning a novel motor skill (throwing with the non-dominant arm) were or were not provided a choice (AS) about the ball color on each of 6 10-trial blocks during practice, and were or were not given bogus positive social-comparative feedback (EE). This resulted in four groups: AS/EE, AS, EE, and C (control). One day after the practice phase, participants completed 10 retention and 10 transfer trials. The distance to the target--a bull's eye with a 1m radius and 10 concentric circles--was 7.5m during practice and retention, and 8.5m during transfer. Autonomy support and enhanced expectancies had additive advantages for learning, with both main effects being significant for retention and transfer. On both tests, the AS/EE group showed the greatest throwing accuracy. Also, the accuracy scores of the AS and EE groups were higher than those of the C group. Furthermore, self-efficacy measured after practice and before retention and transfer was increased by both AS and EE. Thus, supporting learners' need for autonomy by given them a small choice--even though it was not directly related to task performance--and enhancing their performance expectancies appeared to independently influence learning. Copyright © 2014 Elsevier B.V. All rights reserved.

Predictors of 4-Year Retention Among African American and White Community-Dwelling Participants in the UAB Study of Aging

PubMed Central

Allman, Richard M.; Sawyer, Patricia; Crowther, Martha; Strothers, Harry S.; Turner, Timothy; Fouad, Mona N.

2011-01-01

Purpose: To identify racial/ethnic differences in retention of older adults at 3 levels of participation in a prospective observational study: telephone, in-home assessments, and home visits followed by blood draws. Design and Methods: A prospective study of 1,000 community-dwelling Medicare beneficiaries aged 65 years and older included a baseline in-home assessment and telephone follow-up calls at 6-month intervals; at 4 years, participants were asked to complete an additional in-home assessment and have blood drawn. Results: After 4 years, 21.7% died and 0.7% withdrew, leaving 776 participants eligible for follow-up (49% African American; 46% male; 51% rural). Retention for telephone follow-up was 94.5% (N = 733/776); 624/733 (85.1%) had home interviews, and 408/624 (65.4%) had a nurse come to the home for the blood draw. African American race was an independent predictor of participation in in-home assessments, but African American race and rural residence were independent predictors of not participating in a blood draw. Implications: Recruitment efforts designed to demonstrate respect for all research participants, home visits, and telephone follow-up interviews facilitate high retention rates for both African American and White older adults; however, additional efforts are required to enhance participation of African American and rural participants in research requiring blood draws. PMID:21565818

Separation of silver nanoparticles by hollow fiber flow field-flow fractionation: Addition of tannic acid into carrier liquid as a modifier.

PubMed

Saenmuangchin, Rattaporn; Mettakoonpitak, Jaruwan; Shiowatana, Juwadee; Siripinyanond, Atitaya

2015-10-09

A homemade hollow fiber flow-field fractionation (Hf-FlFFF) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was set-up for silver nanoparticles (AgNPs) separation by using polysulfone hollow fiber membrane (30,000 MW cutoff) as a separation channel. Tannic acid and citrate stabilized AgNPs were synthesized and introduced into Hf-FlFFF. The effects of carrier liquid and stabilizing agent on retention behavior of AgNPs were investigated. Different elution behaviors were observed as follows: with 0.02% (w/v) FL-70, all of AgNPs were eluted from Hf-FlFFF but differences in retention behaviors were observed for AgNPs with tannic acid and citrate stabilizing agents; and with 30mM TRIS buffer, only tannic acid stabilized AgNPs were eluted from Hf-FlFFF, whereas citrate stabilized AgNPs were not eluted. In this work, tannic acid addition into carrier liquid was proposed to modify the surface of AgNPs and the surface of the membrane, and thereby adjusting the retention behaviors of AgNPs. Various concentrations of tannic acid were added into FL-70 and TRIS buffer. With the use of 0.1mM tannic acid in 30mM TRIS buffer as the carrier liquid, retention behaviors of both tannic acid stabilized- and citrate stabilized-AgNPs were similar and with similar fractionation recovery. Copyright © 2015 Elsevier B.V. All rights reserved.

Functional chloroplasts in metazoan cells - a unique evolutionary strategy in animal life

PubMed Central

2009-01-01

Background Among metazoans, retention of functional diet-derived chloroplasts (kleptoplasty) is known only from the sea slug taxon Sacoglossa (Gastropoda: Opisthobranchia). Intracellular maintenance of plastids in the slug's digestive epithelium has long attracted interest given its implications for understanding the evolution of endosymbiosis. However, photosynthetic ability varies widely among sacoglossans; some species have no plastid retention while others survive for months solely on photosynthesis. We present a molecular phylogenetic hypothesis for the Sacoglossa and a survey of kleptoplasty from representatives of all major clades. We sought to quantify variation in photosynthetic ability among lineages, identify phylogenetic origins of plastid retention, and assess whether kleptoplasty was a key character in the radiation of the Sacoglossa. Results Three levels of photosynthetic activity were detected: (1) no functional retention; (2) short-term retention lasting about one week; and (3) long-term retention for over a month. Phylogenetic analysis of one nuclear and two mitochondrial loci revealed reciprocal monophyly of the shelled Oxynoacea and shell-less Plakobranchacea, the latter comprising a monophyletic Plakobranchoidea and paraphyletic Limapontioidea. Only species in the Plakobranchoidea expressed short- or long-term kleptoplasty, most belonging to a speciose clade of slugs bearing parapodia (lateral flaps covering the dorsum). Bayesian ancestral character state reconstructions indicated that functional short-term retention arose once in the last common ancestor of Plakobranchoidea, and independently evolved into long-term retention in four derived species. Conclusion We propose a sequential progression from short- to long-term kleptoplasty, with different adaptations involved in each step. Short-term kleptoplasty likely arose as a deficiency in plastid digestion, yielding additional energy via the release of fixed carbon. Functional short-term retention was an apomorphy of the Plakobranchoidea, but the subsequent evolution of parapodia enabled slugs to protect kleptoplasts against high irradiance and further prolong plastid survival. We conclude that functional short-term retention was necessary but not sufficient for an adaptive radiation in the Plakobranchoidea, especially in the genus Elysia which comprises a third of all sacoglossan species. The adaptations necessary for long-term chloroplast survival arose independently in species feeding on different algal hosts, providing a valuable study system for examining the parallel evolution of this unique trophic strategy. PMID:19951407

Adherence of pregnant women to Nordic dietary guidelines in relation to postpartum weight retention: results from the Norwegian Mother and Child Cohort Study.

PubMed

von Ruesten, Anne; Brantsæter, Anne Lise; Haugen, Margaretha; Meltzer, Helle Margrete; Mehlig, Kirsten; Winkvist, Anna; Lissner, Lauren

2014-01-24

Pregnancy is a major life event for women and often connected with changes in diet and lifestyle and natural gestational weight gain. However, excessive weight gain during pregnancy may lead to postpartum weight retention and add to the burden of increasing obesity prevalence. Therefore, it is of interest to examine whether adherence to nutrient recommendations or food-based guidelines is associated with postpartum weight retention 6 months after birth. This analysis is based on data from the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. Diet during the first 4-5 months of pregnancy was assessed by a food-frequency questionnaire and maternal weight before pregnancy as well as in the postpartum period was assessed by questionnaires. Two Healthy Eating Index (HEI) scores were applied to measure compliance with either the official Norwegian food-based guidelines (HEI-NFG) or the Nordic Nutrition Recommendations (HEI-NNR) during pregnancy. The considered outcome, i.e. weight retention 6 months after birth, was modelled in two ways: continuously (in kg) and categorically (risk of substantial postpartum weight retention, i.e. ≥ 5% gain to pre-pregnancy weight). Associations between the HEI-NFG and HEI-NNR score with postpartum weight retention on the continuous scale were estimated by linear regression models. Relationships of both HEI scores with the categorical outcome variable were evaluated using logistic regression. In the continuous model without adjustment for gestational weight gain (GWG), the HEI-NFG score but not the HEI-NNR score was inversely related to postpartum weight retention. However, after additional adjustment for GWG as potential intermediate the HEI-NFG score was marginally inversely and the HEI-NNR score was inversely associated with postpartum weight retention. In the categorical model, both HEI scores were inversely related with risk of substantial postpartum weight retention, independent of adjustment for GWG. Higher adherence to either the official Norwegian food guidelines or possibly also to Nordic Nutrition Recommendations during pregnancy appears to be associated with lower postpartum weight retention.

Adherence of pregnant women to Nordic dietary guidelines in relation to postpartum weight retention: results from the Norwegian Mother and Child Cohort Study

PubMed Central

2014-01-01

Background Pregnancy is a major life event for women and often connected with changes in diet and lifestyle and natural gestational weight gain. However, excessive weight gain during pregnancy may lead to postpartum weight retention and add to the burden of increasing obesity prevalence. Therefore, it is of interest to examine whether adherence to nutrient recommendations or food-based guidelines is associated with postpartum weight retention 6 months after birth. Methods This analysis is based on data from the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. Diet during the first 4-5 months of pregnancy was assessed by a food-frequency questionnaire and maternal weight before pregnancy as well as in the postpartum period was assessed by questionnaires. Two Healthy Eating Index (HEI) scores were applied to measure compliance with either the official Norwegian food-based guidelines (HEI-NFG) or the Nordic Nutrition Recommendations (HEI-NNR) during pregnancy. The considered outcome, i.e. weight retention 6 months after birth, was modelled in two ways: continuously (in kg) and categorically (risk of substantial postpartum weight retention, i.e. ≥ 5% gain to pre-pregnancy weight). Associations between the HEI-NFG and HEI-NNR score with postpartum weight retention on the continuous scale were estimated by linear regression models. Relationships of both HEI scores with the categorical outcome variable were evaluated using logistic regression. Results In the continuous model without adjustment for gestational weight gain (GWG), the HEI-NFG score but not the HEI-NNR score was inversely related to postpartum weight retention. However, after additional adjustment for GWG as potential intermediate the HEI-NFG score was marginally inversely and the HEI-NNR score was inversely associated with postpartum weight retention. In the categorical model, both HEI scores were inversely related with risk of substantial postpartum weight retention, independent of adjustment for GWG. Conclusions Higher adherence to either the official Norwegian food guidelines or possibly also to Nordic Nutrition Recommendations during pregnancy appears to be associated with lower postpartum weight retention. PMID:24456804

Characterising and classifying agricultural drainage channels for sediment and phosphorus management

NASA Astrophysics Data System (ADS)

Shore, Mairead; Jordan, Phil; Mellander, Per-Erik; Quinn, Mary Kelly; Daly, Karen; Sims, James Tom; Melland, Alice

2016-04-01

In agricultural landscapes, surface ditches and streams can significantly influence the attenuation and transfer of sediment and phosphorus (P) from upstream sources to receiving water-bodies. The sediment attenuation and/or transfer capacity of these features depends on channel physical characteristics. This is similar for P, in addition to the sediment physico-chemical characteristics. Therefore, a greater understanding of (i) channel physical characteristics and (ii) the associated sediment physico-chemical characteristics could be used to develop channel-specific management strategies for the reduction of downstream sediment and P transfers. Using a detailed field survey of surface channel networks in a well-drained arable and a poorly-drained grassland catchment (both c.10km2), this study (i) characterised all ditches and streams in both catchments, (ii) investigated the physico-chemical characteristics of sediments in a subset of ditches, (iii) classified all channels into four classes of fine sediment retention and/or transfer likelihood based on a comparison of physical characteristics (slope and drainage area) with observations of fine sediment accumulation and (iv) considered P management strategies that are suited to each class. Mehlich3-Al/P and Mehlich3-Ca/P contents of ditch sediments in the well (non-calcareous) and poorly (calcareous) drained catchments, respectively, indicated potential for soluble P retention (above thresholds of 11.7 and 74, respectively). In general, ditches with low slopes had the greatest potential to retain fine sediment and associated particulate P. As sediments in these catchments are likely to primarily adsorb, rather than release soluble P, these flat ditches are also likely to reduce soluble P loading downstream. Ditches with moderate-high slopes had the greatest potential to mobilise fine sediment and associated P during event flows. Ditch dimensions were not closely related to their indicative flow volumes and were over-engineered, which likely reduces downstream P transfer. Streams had the greatest potential to convey fine sediment and associated P during event flows. Optimising these linear features for eutrophication management in headwaters, periodic removal of fine sediment and maintenance of channel vegetation in net attenuating and transferring channels, respectively, would help to minimise sediment and P transfers from these catchments.

A homozygous mutation in the stem II domain of RNU4ATAC causes typical Roifman syndrome.

PubMed

Dinur Schejter, Yael; Ovadia, Adi; Alexandrova, Roumiana; Thiruvahindrapuram, Bhooma; Pereira, Sergio L; Manson, David E; Vincent, Ajoy; Merico, Daniele; Roifman, Chaim M

2017-01-01

Roifman syndrome (OMIM# 616651) is a complex syndrome encompassing skeletal dysplasia, immunodeficiency, retinal dystrophy and developmental delay, and is caused by compound heterozygous mutations involving the Stem II region and one of the other domains of the RNU4ATAC gene. This small nuclear RNA gene is essential for minor intron splicing. The Canadian Centre for Primary Immunodeficiency Registry and Repository were used to derive patient information as well as tissues. Utilising RNA sequencing methodologies, we analysed samples from patients with Roifman syndrome and assessed intron retention. We demonstrate that a homozygous mutation in Stem II is sufficient to cause the full spectrum of features associated with typical Roifman syndrome. Further, we demonstrate the same pattern of aberration in minor intron retention as found in cases with compound heterozygous mutations.

Metamorphological awareness and EFL students' memory, retention, and retrieval of English adjectival lexicons.

PubMed

Zhang, Lawrence Jun

2002-12-01

Research has shown that foreign or second language learners' metalinguistic awareness has important effects on their acquisition of the target language. Important among a multitude of the concerns are problems these learners encounter when they have to process the morphological features of individual words, particularly in the acquisition of literacy skills. Nevertheless, for students who learn English as a foreign or second language for academic purposes, one of the biggest challenges in their advanced study is how they can effectively remember, retain, and retrieve the colossal number of newly learnt English vocabulary, including adjectival lexicons, to enhance their academic success. Results from the present report on the effects of metamorphological awareness of 65 adult Chinese EFL learners' memory, retention, and retrieval of adjectival lexicons show that, although the subjects in the two groups did not differ significantly in their performance on a pretest designed to check their lexical knowledge and no sex difference was observed, statistically significant differences were found between the two groups in both conditions (immediate and delayed retrievals) on a posttest. The experimental group and women predominantly performed better in the memory-retention-retrieval tasks assigned to them. Implications for educational research and practices are also discussed.

Nutrient retention and fate of iron-binding phenolic compounds during the injera processing of tannin-free and high-tannin sorghum.

PubMed

Seyoum, Yohannes; Retta, Negussie; Baye, Kaleab

2016-03-30

Traits such as bird-, insect- and mould-resistance are the focus in selecting improved sorghum varieties, but this often increases the tannin content, which can negatively affect iron bioavailability. The grain characteristics, nutrient retention, and the fate of iron-binding polyphenols (IBPs) during injera processing, an Ethiopian traditional fermented pancake, were investigated using agriculturally improved tannin-free (TFC) and high-tannin (HTC) sorghum cultivars. The HTC had significantly higher IBP contents than the TFC (P < 0.05). Decortication led to iron (24-27%), calcium (18-43%), IBP (catechol 35-41%, galloyl 35-42%), and tannin (12-35%) losses. Sourdough fermentation reduced the IBP and tannin concentrations in HTC, but had no effect on the IBP concentrations in TFC. The modified injera processing that included pre-soaking resulted in the highest IBP reductions (galloyl 73% and catechol 71%). Nutrient retention in HTC and TFC processing was different. Including a pre-soaking step during injera processing of HTC could counter the negative effects of IBP on iron absorption, while benefiting from the agronomic features of HTC. © 2015 Society of Chemical Industry.

Effect of three mycotoxin adsorbents on growth performance, nutrient retention and meat quality in broilers fed on mould-contaminated feed.

PubMed

Liu, Y L; Meng, G Q; Wang, H R; Zhu, H L; Hou, Y Q; Wang, W J; Ding, B Y

2011-04-01

1. A study was conducted to investigate the effects of an esterified glucomannan (EGM), a hydrated sodium calcium aluminosilicate (HSCAS) and a compound mycotoxin adsorbent (CMA) on performance, nutrient retention and meat quality in broilers fed on mould-contaminated feed. Mould-contaminated diets were prepared by replacing half of the non-contaminated maize in the basal diets with mould-contaminated maize, which contained 450·6 µg/kg of aflatoxin B1, 68·4 µg/kg of ochratoxin A and 320·5 µg/kg of T-2 toxin. 2. The mould-contaminated diet significantly decreased body weight gain (BWG) between 10 and 21 d, feed intake (FI) between 35 and 42 d, the apparent retention of crude lipid and phosphorus, and the lightness (L*) value of breast and thigh muscle. It also significantly increased the redness (a*) and yellowness (b*) value in breast muscle and the b* value in thigh muscle. 3. The addition of 0·2% HSCAS significantly increased FI between 35 and 42 d and the apparent retention of phosphorus. Supplementation with 0·1% CMA in the contaminated diet significantly improved BWG from 10 to 21 d, and increased FI from 35 to 42 d and from 10 to 42 d. CMA also significantly increased the apparent retention of crude lipid, crude protein, ash and phosphorus. All three mycotoxin-adsorbent treatments significantly improved the L* values of breast and thigh muscle when compared with the mould-contaminated group. Supplementation with 0·1% CMA in the contaminated diet significantly decreased b* value and improved tenderness in thigh muscle. 0·05% EGM significantly decreased b* value of thigh muscle compared to mould-contaminated group. 4. The results indicated that mycotoxins in contaminated feed retard growth, nutrient retention and meat quality, whereas the addition of 0·05% EGM, 0·2% HSCAS or 0·1% CMA prevents the adverse effects of mycotoxins to varying extents, with 0·1% CMA being the most effective adsorbent treatment.

Identification of potential biophysical and molecular signalling mechanisms underlying hyaluronic acid enhancement of cartilage formation

PubMed Central

Responte, Donald J.; Natoli, Roman M.; Athanasiou, Kyriacos A.

2012-01-01

This study determined the effects of exogenous hyaluronic acid (HA) on the biomechanical and biochemical properties of self-assembled bovine chondrocytes, and investigated biophysical and genetic mechanisms underlying these effects. The effects of HA commencement time, concentration, application duration and molecular weight were examined using histology, biomechanics and biochemistry. Additionally, the effects of HA application on sulphated glycosaminoglycan (GAG) retention were assessed. To investigate the influence of HA on gene expression, microarray analysis was conducted. HA treatment of developing neocartilage increased compressive stiffness onefold and increased sulphated GAG content by 35 per cent. These effects were dependent on HA molecular weight, concentration and application commencement time. Additionally, applying HA increased sulphated GAG retention within self-assembled neotissue. HA administration also upregulated 503 genes, including multiple genes associated with TGF-β1 signalling. Increased sulphated GAG retention indicated that HA could enhance compressive stiffness by increasing the osmotic pressure that negatively charged GAGs create. The gene expression data demonstrate that HA treatment differentially regulates genes related to TGF-β1 signalling, revealing a potential mechanism for altering matrix composition. These results illustrate the potential use of HA to improve cartilage regeneration efforts and better understand cartilage development. PMID:22809846

Blistering behavior and deuterium retention in tungsten vanadium alloys exposed to deuterium plasma in the linear plasma device STEP

NASA Astrophysics Data System (ADS)

Wang, Jun; Cheng, Long; Yuan, Yue; Qin, Shao-Yang; Arshad, Kameel; Guo, Wang-Guo; Wang, Zheng; Zhou, Zhang-Jian; Lu, Guang-Hong

2018-03-01

The behavior of tungsten-vanadium (W-V) alloys fabricated by powder metallurgy as a plasma facing material has been studied. W-V alloys with different vanadium concentrations (5 and 10 wt %) manufactured by hot pressing (HP) were exposed to deuterium plasma (flux ∼4.6 × 1021 m-2s-1, fluence ∼5.6 × 1025 m-2, ion energy ∼60 eV, target temperature ∼450 K) in the linear plasma device STEP at Beihang University. Three typical grains are observed on HP sintered W-V alloys and exhibit a significant effect on its performance under deuterium plasma irradiation. Surface blistering only occurs at W-enriched grains and is significantly mitigated in W-V alloys, especially in W-10 V, blistering is completely suppressed. On the other hand, deuterium retention dramatically increases in the W-V alloys due to vanadium addition. The deuterium retention in W-5 wt. % V is about 6.2 times more than that in rolled pure W, and this factor further increases to 6.9 when the V concentration rises to 10 wt %. We ascribe these phenomena to the changes of microstructures and components caused by vanadium addition.

Fractionation of poly(methacrylic acid) and poly(vinyl pyridine) in aqueous and organic mobile phases by multidetector thermal field-flow fractionation.

PubMed

Greyling, Guilaume; Pasch, Harald

2017-08-25

Multidetector thermal field-flow fractionation (ThFFF) is shown to be a versatile characterisation platform that can be used to characterise hydrophilic polymers in a variety of organic and aqueous solutions with various ionic strengths. It is demonstrated that ThFFF fractionates isotactic and syndiotactic poly(methacrylic acid) (PMAA) as well as poly(2-vinyl pyridine) (P2VP) and poly(4-vinyl pyridine) (P4VP) according to microstructure in organic solvents and that the ionic strength of the mobile phase has no influence on the retention behaviour of the polymers. With regard to aqueous solutions, it is shown that, despite the weak retention, isotactic and syndiotactic PMAA show different retention behaviours which can qualitatively be attributed to microstructure. Additionally, it is shown that the ionic strength of the mobile phase has a significant influence on the thermal diffusion of polyelectrolytes in aqueous solutions and that the addition of an electrolyte is essential to achieve a microstructure-based separation of P2VP and P4VP in aqueous solutions. Copyright © 2017 Elsevier B.V. All rights reserved.

A clinicopathologic review of 138 cases of mucoceles in a pediatric population.

PubMed

Martins-Filho, Paulo Ricardo Saquete; Santos, Thiago de Santana; da Silva, Heitor Fontes; Piva, Marta Rabello; Andrade, Emanuel Sávio de Souza; da Silva, Luiz Carlos Ferreira

2011-09-01

To evaluate the clinicopathologic features of pediatric mucoceles diagnosed in two public institutions in Brazil during an 18-year period. Clinical data (age, sex, history of trauma, location, and size) of 138 cases of mucoceles in children 0 to 16 years of age were obtained from medical records. The lesions were classified as mucus extravasation phenomenon and mucus retention phenomenon, depending on the presence of epithelial lining in the microscopic analysis. Mucoceles made up 24.5% of the oral pediatric lesions diagnosed in the period of study. Age at diagnosis ranged from 0.4 to 16.0 years, with a mean age of 10.8 years. Of the total of mucoceles, 87 were observed in females and 51 in males. The lower lip was the most commonly affected site, and a history of trauma was related by 87% of the patients. Histologically, 96.4% of mucoceles were diagnosed as mucus extravasation phenomenon. Cases of mucus retention phenomenon were relatively more common in the floor of the mouth, since one in three lesions in this location belonged to this histologic type. Regarding lesions in the lower lip, only 2.65% were diagnosed as mucus retention phenomenon. Trauma is the main etiologic factor involved in the development of mucoceles in children. The mucus extravasation phenomenon is the most common histologic type in this age group. Although rare, the retention type seems to be more common in lesions on the floor of the mouth.

The mitigating effect of repeated memory reactivations on forgetting

NASA Astrophysics Data System (ADS)

MacLeod, Sydney; Reynolds, Michael G.; Lehmann, Hugo

2018-12-01

Memory reactivation is a process whereby cueing or recalling a long-term memory makes it enter a new active and labile state. Substantial evidence suggests that during this state the memory can be updated (e.g., adding information) and can become more vulnerable to disruption (e.g., brain insult). Memory reactivations can also prevent memory decay or forgetting. However, it is unclear whether cueing recall of a feature or component of the memory can benefit retention similarly to promoting recall of the entire memory. We examined this possibility by having participants view a series of neutral images and then randomly assigning them to one of four reactivation groups: control (no reactivation), distractor (reactivation of experimental procedures), component (image category reactivation), and descriptive (effortful description of the images). The experiment also included three retention intervals: 1 h, 9 days, and 28 days. Importantly, the participants received three reactivations equally spaced within their respective retention interval. At the end of the interval, all the participants were given an in-lab free-recall test in which they were asked to write down each image they remembered with as many details as possible. The data revealed that both the participants in the descriptive reactivation and component reactivation groups remembered significantly more than the participants in the control groups, with the effect being most pronounced in the 28-day retention interval condition. These findings suggest that memory reactivation, even component reactivation of a memory, makes memories more resistant to decay.

Transport and Retention of Carboxymethylcellulose-Modified Carbon Nanotube-Magnetite Nanohybrids in Water-Saturated Porous Media

NASA Astrophysics Data System (ADS)

Wang, D.; Su, C.

2017-12-01

Carbon-metal oxide nanohybrids (NHs) are increasingly recognized as the next-generation, promising group of nanomaterials for solving emerging environmental issues and challenges. This research, for the first time, systematically explored the transport and retention of the multifunctional carbon nanotube-magnetite (CNT-Fe3O4) NHs in water-saturated porous media under environmentally relevant physicochemical conditions. An environment-benign macromolecule, carboxymethylcellulose (CMC), was employed to stabilize the NHs. Classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and colloid transport model were used to describe the transport and retention of the NHs. Our results showed that transport of the magnetic CNT-Fe3O4 NHs was lower than that of the parent CNT due to greater aggregation (induced by magnetic attraction) during transport. The DLVO theory well-interpreted the NHs' transport; and secondary minimum played dominant roles in NHs' retention. A novel transport feature, an initial low and following sharp peaks occurred frequently in the NHs' breakthrough curves; and the magnitude and location of both transport peaks varied with different experimental conditions due to the interplay between variability of the fluid viscosity and aggregation-dispersion nature of the NHs. Very promisingly, the estimated maximum transport distance of NHs using the Tufenkji-Elimelech equation ranged between 0.38-46 m, supporting the feasibility of employing the magnetically recyclable CNT-Fe3O4 NHs for in-situ nanoremediation of contaminated soils, sediment aquifers, and groundwater.

High-throughput olfactory conditioning and memory retention test show variation in Nasonia parasitic wasps

PubMed Central

Hoedjes, K M; Steidle, J L M; Werren, J H; Vet, L E M; Smid, H M

2012-01-01

Most of our knowledge on learning and memory formation results from extensive studies on a small number of animal species. Although features and cellular pathways of learning and memory are highly similar in this diverse group of species, there are also subtle differences. Closely related species of parasitic wasps display substantial variation in memory dynamics and can be instrumental to understanding both the adaptive benefit of and mechanisms underlying this variation. Parasitic wasps of the genus Nasonia offer excellent opportunities for multidisciplinary research on this topic. Genetic and genomic resources available for Nasonia are unrivaled among parasitic wasps, providing tools for genetic dissection of mechanisms that cause differences in learning. This study presents a robust, high-throughput method for olfactory conditioning of Nasonia using a host encounter as reward. A T-maze olfactometer facilitates high-throughput memory retention testing and employs standardized odors of equal detectability, as quantified by electroantennogram recordings. Using this setup, differences in memory retention between Nasonia species were shown. In both Nasonia vitripennis and Nasonia longicornis, memory was observed up to at least 5 days after a single conditioning trial, whereas Nasonia giraulti lost its memory after 2 days. This difference in learning may be an adaptation to species-specific differences in ecological factors, for example, host preference. The high-throughput methods for conditioning and memory retention testing are essential tools to study both ultimate and proximate factors that cause variation in learning and memory formation in Nasonia and other parasitic wasp species. PMID:22804968

Enhanced production of poly(3-hydroxybutyrate) in a novel airlift reactor with in situ cell retention using Azohydromonas australica.

PubMed

Gahlawat, Geeta; Sengupta, Bedoshree; Srivastava, Ashok K

2012-09-01

Economic production of biodegradable plastics is a challenge particularly because of high substrate and energy cost inputs for its production. Research efforts are being directed towards innovations to minimize both of the above costs to economize polyhydroxybutyrate (PHB) production. A novel airlift reactor (ALR) with outer aeration and internal settling was utilized in this investigation. Although it featured no power consumption for agitation, it facilitated increased oxygen transfer rate and better cell retention than stirred tank reactor (STR), thereby resulting in enhanced PHB productivity. ALR with in situ cell retention demonstrated a significant improvement in biomass concentration and biopolymer accumulation. The total PHB production rate, specific biomass, and product yield in the ALR were observed to be 0.84 g/h, 0.43 g/g, and 0.32 g/g, respectively. The studies revealed that the volumetric oxygen mass transfer rate and mixing time for ALR were 0.016 s⁻¹ and 3.73 s, respectively, at 2.0 vvm as compared with corresponding values of 0.005 s⁻¹ and 4.95 s, respectively, in STR. This demonstrated that ALR has better oxygen mass transfer and mixing efficiency than STR. Hence, ALR with cell retention would serve as a better bioreactor design for economic biopolymer production than STR, particularly due to its lower cost of operation and simplicity along with its enhanced oxygen and heat transfer rates.

Glucocorticoid effects on object recognition memory require training-associated emotional arousal.

PubMed

Okuda, Shoki; Roozendaal, Benno; McGaugh, James L

2004-01-20

Considerable evidence implicates glucocorticoid hormones in the regulation of memory consolidation and memory retrieval. The present experiments investigated whether the influence of these hormones on memory depends on the level of emotional arousal induced by the training experience. We investigated this issue in male Sprague-Dawley rats by examining the effects of immediate posttraining systemic injections of the glucocorticoid corticosterone on object recognition memory under two conditions that differed in their training-associated emotional arousal. In rats that were not previously habituated to the experimental context, corticosterone (0.3, 1.0, or 3.0 mg/kg, s.c.) administered immediately after a 3-min training trial enhanced 24-hr retention performance in an inverted-U shaped dose-response relationship. In contrast, corticosterone did not affect 24-hr retention of rats that received extensive prior habituation to the experimental context and, thus, had decreased novelty-induced emotional arousal during training. Additionally, immediate posttraining administration of corticosterone to nonhabituated rats, in doses that enhanced 24-hr retention, impaired object recognition performance at a 1-hr retention interval whereas corticosterone administered after training to well-habituated rats did not impair 1-hr retention. Thus, the present findings suggest that training-induced emotional arousal may be essential for glucocorticoid effects on object recognition memory.

Thermocapillary flow with evaporation and condensation and its effect on liquid retention in low-G fluid acquisition devices

NASA Technical Reports Server (NTRS)

Schmidt, George R.

1994-01-01

The steady motion, thermal and free surface behavior of a volatile, wetting liquid in microgravity are studied using scaling and numerical techniques. The objective is to determine whether the thermocapillary and two-phase convection arising from thermodynamic nonequilibrium along the porous surfaces of spacecraft liquid acquisition devices could cause the retention failures observed with liquid hydrogen and heated vapor pressurant. Why these devices seem immune to retention loss when pressurized with heated helium or heated directly through the porous structure was also examined. Results show that highly wetting fluids exhibit large negative and positive dynamic pressure gradients towards the meniscus interline when superheated and subcooled, respectively. With superheating, the pressure variation and recoil force arising from liquid/vapor phase change exert the same influence on surface morphology and promote retention. With subcooling, however, the pressure distribution produces a suction that degrades mechanical equilibrium of the surface. This result indicates that thermocapillary-induced deformation arising from subcooling and condensation is the likely cause for retention loss. In addition, increasing the level of nonequilibrium by reducing accommodation coefficient suppresses deformation and explains why this failure mode does not occur in instances of direct screen heating or pressurization with a heated inert gas.

Auxiliary KChIP4a Suppresses A-type K+ Current through Endoplasmic Reticulum (ER) Retention and Promoting Closed-state Inactivation of Kv4 Channels*

PubMed Central

Tang, Yi-Quan; Liang, Ping; Zhou, Jingheng; Lu, Yanxin; Lei, Lei; Bian, Xiling; Wang, KeWei

2013-01-01

In the brain and heart, auxiliary Kv channel-interacting proteins (KChIPs) co-assemble with pore-forming Kv4 α-subunits to form a native K+ channel complex and regulate the expression and gating properties of Kv4 currents. Among the KChIP1–4 members, KChIP4a exhibits a unique N terminus that is known to suppress Kv4 function, but the underlying mechanism of Kv4 inhibition remains unknown. Using a combination of confocal imaging, surface biotinylation, and electrophysiological recordings, we identified a novel endoplasmic reticulum (ER) retention motif, consisting of six hydrophobic and aliphatic residues, 12–17 (LIVIVL), within the KChIP4a N-terminal KID, that functions to reduce surface expression of Kv4-KChIP complexes. This ER retention capacity is transferable and depends on its flanking location. In addition, adjacent to the ER retention motif, the residues 19–21 (VKL motif) directly promote closed-state inactivation of Kv4.3, thus leading to an inhibition of channel current. Taken together, our findings demonstrate that KChIP4a suppresses A-type Kv4 current via ER retention and enhancement of Kv4 closed-state inactivation. PMID:23576435

Quantitative structure-retention relationship studies for taxanes including epimers and isomeric metabolites in ultra fast liquid chromatography.

PubMed

Dong, Pei-Pei; Ge, Guang-Bo; Zhang, Yan-Yan; Ai, Chun-Zhi; Li, Guo-Hui; Zhu, Liang-Liang; Luan, Hong-Wei; Liu, Xing-Bao; Yang, Ling

2009-10-16

Seven pairs of epimers and one pair of isomeric metabolites of taxanes, each pair of which have similar structures but different retention behaviors, together with additional 13 taxanes with different substitutions were chosen to investigate the quantitative structure-retention relationship (QSRR) of taxanes in ultra fast liquid chromatography (UFLC). Monte Carlo variable selection (MCVS) method was adopted to choose descriptors. The selected four descriptors were used to build QSRR model with multi-linear regression (MLR) and artificial neural network (ANN) modeling techniques. Both linear and nonlinear models show good predictive ability, of which ANN model was better with the determination coefficient R(2) for training, validation and test set being 0.9892, 0.9747 and 0.9840, respectively. The results of 100 times' leave-12-out cross validation showed the robustness of this model. All the isomers can be correctly differentiated by this model. According to the selected descriptors, the three dimensional structural information was critical for recognition of epimers. Hydrophobic interaction was the uppermost factor for retention in UFLC. Molecules' polarizability and polarity properties were also closely correlated with retention behaviors. This QSRR model will be useful for separation and identification of taxanes including epimers and metabolites from botanical or biological samples.

Effect of grilling and baking on physicochemical and textural properties of tilapia (Oreochromis niloticus) fish burger.

PubMed

Bainy, Eduarda Molardi; Bertan, Larissa Canhadas; Corazza, Marcos Lucio; Lenzi, Marcelo Kaminski

2015-08-01

The influence of two common cooking methods, grilling and baking, on chemical composition, water retention, fat retention, cooking yield, diameter reduction, expressible water, color and mechanical texture of tilapia (Oreochromis niloticus) fish burgers was investigated. Texture analyses were performed using a Warner-Bratzler test. The fish burger had a softer texture with a lower shear force than other meat products reported in the literature. There were no significant differences in proximate composition, diameter reduction, fat retention and expressible water between the grilled and oven-baked fish burgers. Cooking methods did not affect the cooking times and cooking rates. Warner-Bratzler parameters and color were significantly influenced by the cooking method. Grilling contributed to a shear force and work of shearing increase due to the lower cooking yield and water retention. Raw burgers had the highest L* (69.13 ± 0.96) and lowest b* (17.50 ± 0.75) values. Results indicated that baking yielded a product with better cooking characteristics, such as a desired softer texture with lower shear values (4.01 ± 0.54) and increased water retention (95.82 ± 0.77). Additionally, the baked fish burgers were lighter (higher L*) and less red (lower a*) than the grilled ones.

Anatomic Customization of Root-Analog Dental Implants With Cone-Beam CT and CAD/CAM Fabrication: A Cadaver-Based Pilot Evaluation.

PubMed

Evans, Zachary P; Renne, Walter G; Bacro, Thierry R; Mennito, Anthony S; Ludlow, Mark E; Lecholop, Michael K

2018-02-01

Existing root-analog dental implant systems have no standardized protocols regarding retentive design, surface manipulation, or prosthetic attachment design relative to the site's unique anatomy. Historically, existing systems made those design choices arbitrarily. For this report, strategies were developed that deliberately reference the adjacent anatomy, implant and restorable path of draw, and bone density for implant and retentive design. For proof of concept, dentate arches from human cadavers were scanned using cone-beam computed tomography and then digitally modeled. Teeth of interest were virtually extracted and manipulated via computer-aided design to generate root-analog implants from zirconium. We created a stepwise protocol for analyzing and developing the implant sites, implant design and retention, and prosthetic emergence and connection all from the pre-op cone-beam data. Root-analog implants were placed at the time of extraction and examined radiographically and mechanically concerning ideal fit and stability. This study provides proof of concept that retentive root-analog implants can be produced from cone-beam data while improving fit, retention, safety, esthetics, and restorability when compared to the existing protocols. These advancements may provide the critical steps necessary for clinical relevance and success of immediately placed root-analog implants. Additional studies are necessary to validate the model prior to clinical trial.

Auxiliary KChIP4a suppresses A-type K+ current through endoplasmic reticulum (ER) retention and promoting closed-state inactivation of Kv4 channels.

PubMed

Tang, Yi-Quan; Liang, Ping; Zhou, Jingheng; Lu, Yanxin; Lei, Lei; Bian, Xiling; Wang, KeWei

2013-05-24

In the brain and heart, auxiliary Kv channel-interacting proteins (KChIPs) co-assemble with pore-forming Kv4 α-subunits to form a native K(+) channel complex and regulate the expression and gating properties of Kv4 currents. Among the KChIP1-4 members, KChIP4a exhibits a unique N terminus that is known to suppress Kv4 function, but the underlying mechanism of Kv4 inhibition remains unknown. Using a combination of confocal imaging, surface biotinylation, and electrophysiological recordings, we identified a novel endoplasmic reticulum (ER) retention motif, consisting of six hydrophobic and aliphatic residues, 12-17 (LIVIVL), within the KChIP4a N-terminal KID, that functions to reduce surface expression of Kv4-KChIP complexes. This ER retention capacity is transferable and depends on its flanking location. In addition, adjacent to the ER retention motif, the residues 19-21 (VKL motif) directly promote closed-state inactivation of Kv4.3, thus leading to an inhibition of channel current. Taken together, our findings demonstrate that KChIP4a suppresses A-type Kv4 current via ER retention and enhancement of Kv4 closed-state inactivation.

Analogue Evaluation of the Effects of Opportunities to Respond and Ratios of Known Items within Drill Rehearsal of Esperanto Words

ERIC Educational Resources Information Center

Szadokierski, Isadora; Burns, Matthew K.

2008-01-01

Drill procedures have been used to increase the retention of various types of information, but little is known about the causal mechanisms of these techniques. The current study compared the effect of two key features of drill procedures, a large number of opportunities to respond (OTR) and a drill ratio that maintains a high percentage of known…

Memristor-integrated voltage-stabilizing supercapacitor system.

PubMed

Liu, Bin; Liu, Boyang; Wang, Xianfu; Wu, Xinghui; Zhao, Wenning; Xu, Zhimou; Chen, Di; Shen, Guozhen

2014-08-06

Voltage-stabilized supercapacitors: A single supercapacitor formed with PCBM/Pt/IPS nanorod-array electrodes is designed and delivers enhanced areal capacitance, capacitance retention, and excellent electrical stability under bending, while a significant voltage-decrease is observed during the discharging process. Once integrated with the memristor, the memristor-integrated supercapacitor systems deliver an extremely low voltage-drop, indicating greatly enhanced voltage-stabilizing features. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Female peer mentors early in college increase women’s positive academic experiences and retention in engineering

PubMed Central

Dasgupta, Nilanjana

2017-01-01

Scientific and engineering innovation is vital for American competitiveness, quality of life, and national security. However, too few American students, especially women, pursue these fields. Although this problem has attracted enormous attention, rigorously tested interventions outside artificial laboratory settings are quite rare. To address this gap, we conducted a longitudinal field experiment investigating the effect of peer mentoring on women’s experiences and retention in engineering during college transition, assessing its impact for 1 y while mentoring was active, and an additional 1 y after mentoring had ended. Incoming women engineering students (n = 150) were randomly assigned to female or male peer mentors or no mentors for 1 y. Their experiences were assessed multiple times during the intervention year and 1-y postintervention. Female (but not male) mentors protected women’s belonging in engineering, self-efficacy, motivation, retention in engineering majors, and postcollege engineering aspirations. Counter to common assumptions, better engineering grades were not associated with more retention or career aspirations in engineering in the first year of college. Notably, increased belonging and self-efficacy were significantly associated with more retention and career aspirations. The benefits of peer mentoring endured long after the intervention had ended, inoculating women for the first 2 y of college—the window of greatest attrition from science, technology, engineering, and mathematics (STEM) majors. Thus, same-gender peer mentoring for a short period during developmental transition points promotes women’s success and retention in engineering, yielding dividends over time. PMID:28533360

Female peer mentors early in college increase women's positive academic experiences and retention in engineering.

PubMed

Dennehy, Tara C; Dasgupta, Nilanjana

2017-06-06

Scientific and engineering innovation is vital for American competitiveness, quality of life, and national security. However, too few American students, especially women, pursue these fields. Although this problem has attracted enormous attention, rigorously tested interventions outside artificial laboratory settings are quite rare. To address this gap, we conducted a longitudinal field experiment investigating the effect of peer mentoring on women's experiences and retention in engineering during college transition, assessing its impact for 1 y while mentoring was active, and an additional 1 y after mentoring had ended. Incoming women engineering students ( n = 150) were randomly assigned to female or male peer mentors or no mentors for 1 y. Their experiences were assessed multiple times during the intervention year and 1-y postintervention. Female (but not male) mentors protected women's belonging in engineering, self-efficacy, motivation, retention in engineering majors, and postcollege engineering aspirations. Counter to common assumptions, better engineering grades were not associated with more retention or career aspirations in engineering in the first year of college. Notably, increased belonging and self-efficacy were significantly associated with more retention and career aspirations. The benefits of peer mentoring endured long after the intervention had ended, inoculating women for the first 2 y of college-the window of greatest attrition from science, technology, engineering, and mathematics (STEM) majors. Thus, same-gender peer mentoring for a short period during developmental transition points promotes women's success and retention in engineering, yielding dividends over time.

Buried particulate organic carbon stimulates denitrification and nitrate retention in stream sediments at the groundwater-surface water interface

USGS Publications Warehouse

Stelzer, Robert S.; Scott, J. Thad; Bartsch, Lynn

2015-01-01

The interface between ground water and surface water in streams is a hotspot for N processing. However, the role of buried organic C in N transformation at this interface is not well understood, and inferences have been based largely on descriptive studies. Our main objective was to determine how buried particulate organic C (POC) affected denitrification and NO3− retention in the sediments of an upwelling reach in a sand-plains stream in Wisconsin. We manipulated POC in mesocosms inserted in the sediments. Treatments included low and high quantities of conditioned red maple leaves (buried beneath combusted sand), ambient sediment (sand containing background levels of POC), and a control (combusted sand). We measured denitrification rates in sediments by acetylene-block assays in the laboratory and by changes in N2 concentrations in the field using membrane inlet mass spectrometry. We measured NO3−, NH4+, and dissolved organic N (DON) retention as changes in concentrations and fluxes along groundwater flow paths in the mesocosms. POC addition drove oxic ground water to severe hypoxia, led to large increases in dissolved organic C (DOC), and strongly increased denitrification rates and N (NO3− and total dissolved N) retention relative to the control. In situ denitrification accounted for 30 to 60% of NO3− retention. Our results suggest that buried POC stimulated denitrification and NO3− retention by producing DOC and by creating favorable redox conditions for denitrification.

Thorough investigation of the retention mechanisms and retention behavior of amides and sulfonamides on amino column in hydrophilic interaction liquid chromatography.

PubMed

Jovanović, Marko; Stojanović, Biljana Jančić

2013-08-02

In this paper detailed analysis of a mixture of four amides (tropicamide, nicotinamide, tiracetam, and piracetam) and six sulfonamides (sulfanilamide, sulfacetamide, sulfamethoxazole, sulfafurazole, furosemide, and bumetanide) on aminopropyl column in hydrophilic interaction chromatography (HILIC) was carried out. Since, there are no papers on the topic of the assessment of the contribution of ion-exchange retention mechanism involved in the separation of the acidic compounds on aminopropyl column in HILIC mode, the authors utilized the retention data of the acidic sulfonamides for this purpose. Next, broad range of the aqueous buffer concentrations in the mobile phase was examined providing the separation under either HILIC or RP conditions. Turning points between these two mechanisms were determined and then the fitting of the experimental data in the localized and non-localized adsorption models in both RP and HILIC regions was assessed. Since not many papers in the literature were dealing with the estimation of factor influence on the retention behavior of neutral and acidic compounds on aminopropyl column in HILIC, Box-Behnken design and Response Surface Methodology were applied. On the basis of the obtained data, ten quadratic models were proposed and their adequacy was confirmed using ANOVA test. Furthermore, retention data was graphically evaluated by the construction of 3D response surface plots. Finally, good predictive ability of the suggested models was proved with five additional verification experiments. Copyright © 2013 Elsevier B.V. All rights reserved.

Portable conduit retention apparatus for releasably retaining a conduit therein

DOEpatents

Metzger, R.H.

1998-07-07

Portable conduit retention apparatus is described for releasably retaining a conduit therein. The apparatus releasably retains the conduit out of the way of nearby personnel and equipment. The apparatus includes a portable support frame defining a slot therein having an open mouth portion in communication with the slot for receiving the conduit through the open mouth portion and into the slot. A retention bar is pivotally connected to the support frame adjacent the mouth portion for releasably retaining the conduit in the slot. The retention bar freely pivots to a first position, so that the mouth portion is unblocked in order that the conduit is received through the mouth portion and into the slot. In addition, the retention bar freely pivots to a second position, so that the mouth portion is blocked in order that the conduit is retained in the slot. The conduit is released from the slot by pivoting the retention bar to the first position to unblock the mouth portion and thereafter manipulating the conduit from the slot and through the mouth portion. The apparatus may further include a mounting member attached to the support frame for mounting the apparatus on a vertical support surface. Another embodiment of the apparatus includes a shoe assembly of predetermined weight removably connected to the support frame for resting the apparatus on a floor in such a manner that the apparatus is substantially stationary on the floor. 6 figs.

The utility of monetary contingency contracts for weight loss: a systematic review and meta-analysis.

PubMed

Sykes-Muskett, Bianca J; Prestwich, Andrew; Lawton, Rebecca J; Armitage, Christopher J

2015-01-01

Financial incentives to improve health have received increasing attention, but are subject to ethical concerns. Monetary Contingency Contracts (MCCs), which require individuals to deposit money that is refunded contingent on reaching a goal, are a potential alternative strategy. This review evaluates systematically the evidence for weight loss-related MCCs. Randomised controlled trials testing the effect of weight loss-related MCCs were identified in online databases. Random-effects meta-analyses were used to calculate overall effect sizes for weight loss and participant retention. The association between MCC characteristics and weight loss/participant retention effects was calculated using meta-regression. There was a significant small-to-medium effect of MCCs on weight loss during treatment when one outlier study was removed. Group refunds, deposit not paid as lump sum, participants setting their own deposit size and additional behaviour change techniques were associated with greater weight loss during treatment. Post-treatment, there was no significant effect of MCCs on weight loss. There was a significant small-to-medium effect of MCCs on participant retention during treatment. Researcher-set deposits paid as one lump sum, refunds delivered on an all-or-nothing basis and refunds contingent on attendance at classes were associated with greater retention during treatment. Post-treatment, there was no significant effect of MCCs on participant retention. The results support the use of MCCs to promote weight loss and participant retention up to the point that the incentive is removed and identifies the conditions under which MCCs work best.

Meningitis-retention syndrome. An unrecognized clinical condition.

PubMed

Sakakibara, Ryuji; Uchiyama, Tomoyuki; Liu, Zhi; Yamamoto, Tatsuya; Ito, Takashi; Uzawa, Akiyuki; Suenaga, Tadahiro; Kanai, Kazuaki; Awa, Yusuke; Sugiyama, Yoshiki; Hattori, Takamichi

2005-12-01

A combination of acute urinary retention and aseptic meningitis has not been well known. This combination can be referred to as meningitis-retention syndrome (MRS), when accompanied by no other abnormalities. To describe the results of a uro-neurological assessment in our patients with MRS. In three patients (two men, one woman; age, 34-68 years), we performed urodynamic studies and relevant imaging and neurophysiological tests, in addition to cerebrospinal fluid (CSF) examination. All three patients developed acute urinary retention along with headache, fever and stiff neck. None had obvious neurological abnormalities, other than a slightly brisk reflex in the lower extremities. One had previously experienced generalized erythematous eruptions, but none had pain, hypalgesia or skin eruptions in the sacral dermatomes suggestive of Elsberg syndrome (infectious sacral polyradiculitis; mostly genital herpes). Brain/spinal/lumbar plexus MRI scans and nerve conduction studies were normal. CSF examination showed mild mononuclear pleocytosis, increased protein content, and normal to mildly decreased glucose content in all patients; increased myelin basic protein suggestive of central nervous system demyelination in one; and increased viral titers in none. Urodynamic study revealed, during the voiding phase, an underactive detrusor in all patients and an unrelaxing sphincter in one. These clinical manifestations were ameliorated within 3 weeks. We reported three cases of MRS, a peculiar syndrome that could be regarded as a mild variant of acute disseminated encephalomyelitis (ADEM). Urinary retention might reflect acute shock phase of this disorder. Although MRS has a benign and self-remitting course, management of the acute urinary retention is necessary.

Chromatographic retention prediction and octanol-water partition coefficient determination of monobasic weak acidic compounds in ion-suppression reversed-phase liquid chromatography using acids as ion-suppressors.

PubMed

Ming, Xin; Han, Shu-ying; Qi, Zheng-chun; Sheng, Dong; Lian, Hong-zhen

2009-08-15

Although simple acids, replacing buffers, have been widely applied to suppress the ionization of weakly ionizable acidic analytes in reversed-phase liquid chromatography (RPLC), none of the previously reported works focused on the systematic studies about the retention behavior of the acidic solutes in this ion-suppression RPLC mode. The subject of this paper was therefore to investigate the retention behavior of monobasic weak acidic compounds using acetic, perchloric and phosphoric acids as the ion-suppressors. The apparent octanol-water partition coefficient (K" ow) was proposed to calibrate the octanol-water partition coefficient (K(ow)) of these weak acidic compounds, which resulted in a better linear correlation with log k(w), the logarithm of the hypothetical retention factor corresponding to neat aqueous fraction of hydroorganic mobile phase. This log K" ow-log k w linear correlation was successfully validated by the results of monocarboxylic acids and monohydrating phenols, and moreover by the results under diverse experimental conditions for the same solutes. This straightforward relationship not only can be used to effectively predict the retention values of weak acidic solutes combined with Snyder-Soczewinski equation, but also can offer a promising medium for directly measuring K(ow) data of these compounds via Collander equation. In addition, the influence of the different ion-suppressors on the retention of weak acidic compounds was also compared in this RPLC mode.

The Effects of Test Trial and Processing Level on Immediate and Delayed Retention.

PubMed

Chang, Sau Hou

2017-03-01

The purpose of the present study was to investigate the effects of test trial and processing level on immediate and delayed retention. A 2 × 2 × 2 mixed ANOVAs was used with two between-subject factors of test trial (single test, repeated test) and processing level (shallow, deep), and one within-subject factor of final recall (immediate, delayed). Seventy-six college students were randomly assigned first to the single test (studied the stimulus words three times and took one free-recall test) and the repeated test trials (studied the stimulus words once and took three consecutive free-recall tests), and then to the shallow processing level (asked whether each stimulus word was presented in capital letter or in small letter) and the deep processing level (whether each stimulus word belonged to a particular category) to study forty stimulus words. The immediate test was administered five minutes after the trials, whereas the delayed test was administered one week later. Results showed that single test trial recalled more words than repeated test trial in immediate final free-recall test, participants in deep processing performed better than those in shallow processing in both immediate and delayed retention. However, the dominance of single test trial and deep processing did not happen in delayed retention. Additional study trials did not further enhance the delayed retention of words encoded in deep processing, but did enhance the delayed retention of words encoded in shallow processing.

The Effects of Test Trial and Processing Level on Immediate and Delayed Retention

PubMed Central

Chang, Sau Hou

2017-01-01

The purpose of the present study was to investigate the effects of test trial and processing level on immediate and delayed retention. A 2 × 2 × 2 mixed ANOVAs was used with two between-subject factors of test trial (single test, repeated test) and processing level (shallow, deep), and one within-subject factor of final recall (immediate, delayed). Seventy-six college students were randomly assigned first to the single test (studied the stimulus words three times and took one free-recall test) and the repeated test trials (studied the stimulus words once and took three consecutive free-recall tests), and then to the shallow processing level (asked whether each stimulus word was presented in capital letter or in small letter) and the deep processing level (whether each stimulus word belonged to a particular category) to study forty stimulus words. The immediate test was administered five minutes after the trials, whereas the delayed test was administered one week later. Results showed that single test trial recalled more words than repeated test trial in immediate final free-recall test, participants in deep processing performed better than those in shallow processing in both immediate and delayed retention. However, the dominance of single test trial and deep processing did not happen in delayed retention. Additional study trials did not further enhance the delayed retention of words encoded in deep processing, but did enhance the delayed retention of words encoded in shallow processing. PMID:28344679

Fine-needle aspiration cytology of mucous retention cyst of the tongue: distinction from other cystic lesions of the tongue.

PubMed

De Las Casas, L E; Bardales, R H

2000-05-01

Mucous retention cyst (MRC) is a common submucosal lesion of the oral cavity that, when deeply seated, simulates a neoplasm. This report describes the fine-needle aspiration cytology findings of a lingual MRC of complex architecture and with metaplastic epithelium. In addition, we emphasize its cytologic differential diagnosis from other benign and malignant cystic lesions of the tongue. To the best of our knowledge, this is the first report of aspiration cytology of a complex MRC of the tongue. Copyright 2000 Wiley-Liss, Inc.

A Fuzzy ARTMAP Approach To The Incorporation Of Chromatographic Retention Time Information To An MS Based E-Nose

NASA Astrophysics Data System (ADS)

Burian, Cosmin; Brezmes, Jesus; Vinaixa, Maria; Llobet, Eduard; Vilanova, Xavier; Cañellas, Nicolau; Correig, Xavier

2009-05-01

This paper presents the work done with Fuzzy ARTMAP neural networks in order to improve the performance of mass spectrometry-based electronic noses using the time retention of a chromatographic column as additional information. Solutions of nine isomers of dimethylphenols and ethylphenols were used in this experiment. The gas chromatograph mass spectrometer response was analyzed with an in-house developed Fuzzy ARTMAP neural network, showing that the combined information (GC plus MS) gives better results than MS information alone.

Polymeric additive performance in closed whitewater systems

Treesearch

T. H. Wegner

1984-01-01

“With more stringent requirements on discharge water quality and with escalating water treatment costs, water recycling within the paper mill is of growing importance. A serious problem resulting from more white-water recycling is reduced drainage and fiber or fines retention because of diminished polymeric additive performance. To provide better insight for overcoming...

Porous Graphene Sponge Additives for Lithium Ion Batteries with Excellent Rate Capability.

PubMed

Cheng, Qian

2017-04-19

Rate capability as well as power performance of lithium ion batteries (LiBs) is becoming more and more important, especially as the application targets of LiBs move from mobile devices to transportation, such as EVs and HEVs. In this research, we report porous graphene sponge additives for both anode and cathode materials for better rate performance. The charge capacity retention improved from 56% to 77% at 6C and from 7% to 45% at 10C with 0.5 wt% added to the anode, while the discharge capacity retention at the 6C rate improved from 43% to 76% and the 10C rate discharge improved from 16% to 40% with the same amount of MG added to the cathode. The cyclability at high rate was also improved with the MG additive. Moreover, preparation of the MG was facile, cost-effective, and compatible with commercially available active materials. These results demonstrate the suitability of MG for use with LiB additives to ensure better rate capability and high rate cyclability.

Phonologic errors as a clinical marker of the logopenic variant of PPA.

PubMed

Leyton, Cristian E; Ballard, Kirrie J; Piguet, Olivier; Hodges, John R

2014-05-06

To disentangle the clinical heterogeneity of nonsemantic variants of primary progressive aphasia (PPA) and to identify a coherent linguistic-anatomical marker for the logopenic variant of PPA (lv-PPA). Key speech and language features of 14 cases of lv-PPA and 18 cases of nonfluent/agrammatic variant of PPA were systematically evaluated and scored by an independent rater blinded to diagnosis. Every case underwent a structural MRI and a Pittsburgh compound B (PiB)-PET scan, a putative biomarker of Alzheimer disease. Key speech and language features that showed association with the PiB-PET status were entered into a hierarchical cluster analysis. The linguistic features and patterns of cortical thinning in each resultant cluster were analyzed. The cluster analysis revealed 3 coherent clinical groups, each of which was linked to a specific PiB-PET status. The first cluster was linked to high PiB retention and characterized by phonologic errors and cortical thinning focused on the left superior temporal gyrus. The second and third clusters were characterized by grammatical production errors and motor speech disorders, respectively, and were associated with low PiB brain retention. A fourth cluster, however, demonstrated nonspecific language deficits and unpredictable PiB-PET status. These findings suggest that despite the clinical and pathologic heterogeneity of nonsemantic variants, discrete clinical syndromes can be distinguished and linked to specific likelihood of PiB-PET status. Phonologic errors seem to be highly predictive of high amyloid burden in PPA and can provide a specific clinical marker for lv-PPA.

Combination prosthetic design providing a superior retention for mid-facial defect rehabilitation: A Case Report

PubMed Central

Nilanonth, Supassra; Shakya, Prana; Srithavaj, Theerathavaj

2017-01-01

Large maxillofacial defects from malignant tumor treatment are rarely rehabilitated by surgical reconstruction alone. Ameloblastic carcinoma, a rare aggressive odontogenic malignant tumor, requires wide surgical excision to gain a tumor-free margin. In the post-surgical defect, prosthetic rehabilitation is the treatment of choice to restore function and esthetics. Moreover, an intra-oral prosthesis such as an obturator restores speech, mastication and deglutition. Retention of the obturator is a major problem while rehabilitating large defects. The existing anatomical structures from the defect with the help of magnet attachments are suitable to enhance retention, stability and support of the prostheses. This case report presents a patient with an intraoral and extra-oral combination defect following surgical resection of ameloblastic carcinoma and describes the prosthetic techniques and design considerations for a magnet-retained obturator and mid-facial prosthesis. An implant-retained mid-facial prosthesis was fabricated. The retention of combined prostheses was obtained from the remaining right posterior teeth only. The patient had an unfavorable defect due to the large size and presence of scar contracture that vertically tends to dislodge the obturator. Magnet attachments were used to combine the facial and oral prosthesis, minimize the vertical dislodging forces and enhance retention. In addition, the retention was also gained from the scar band at lower border of mid-facial defect that avoided the need for more implants surgery. Magnet attachment with anatomical structure of the mid-facial defect provides an acceptable means of retention in large extraoral-intraoral combinations defects, improving the function, esthetic and the patients’ quality of life. Key words:Mid-facial prosthesis, obturator, magnet attachment, maxillectomy. PMID:28469829

Improving Participants’ Retention in a Smoking Cessation Intervention Using a Community-based Participatory Research Approach

PubMed Central

Estreet, Anthony; Apata, Jummai; Kamangar, Farin; Schutzman, Christine; Buccheri, Jane; O’Keefe, Anne-Marie; Wagner, Fernando; Sheikhattari, Payam

2017-01-01

Background: This study compares participant’ sretention in three phases of smoking cessation interventions, one provided in a health clinic and the subsequent two in community-based settings. Methods: Smoking cessation interventions were conducted in three phases from 2008 to 2015 in two underserved urban communities with low socioeconomic profiles and high rates of smoking (n = 951). Phase I was conducted in a clinic; Phases II and III were conducted in community venues. In Phases II and III, incremental changes were made based on lessons learned from the previous phases. Retention (attending six or more sessions) was the primary predictor of cessation and was analyzed while controlling for associated factors including age, gender, race, employment, education, and nicotine dependence. Results: Retention increased substantially over the three phases, with rates for attending six or more sessions of 13.8%, 51.9%, and 67.9% in Phases I, II, and III, respectively. Retention was significantly higher in community settings than in the clinic setting (adjusted odds ratio [OR] = 6.7; 95% confidence intervals [CI] = 4.6, 9.8). In addition to the intervention in community venues, predictors of retention included age and unemployment. Higher retention was significantly associated with higher quit rates (adjusted OR = 2.4; 95% CI = 1.5, 3.8). Conclusions: Conducting the intervention in community settings using trained peer motivators rather than health-care providers resulted in significantly higher retention and smoking cessation rates. This was due in part to the ability to tailor cessation classes in the community for specific populations and improving the quality of the intervention based on feedback from participants and community partners. PMID:29416835

Effect, Feasibility, and Clinical Relevance of Cell Enrichment in Large Volume Fat Grafting: A Systematic Review.

PubMed

Rasmussen, Bo Sonnich; Lykke Sørensen, Celine; Vester-Glowinski, Peter Viktor; Herly, Mikkel; Trojahn Kølle, Stig-Frederik; Fischer-Nielsen, Anne; Drzewiecki, Krzysztof Tadeusz

2017-07-01

Large volume fat grafting is limited by unpredictable volume loss; therefore, methods of improving graft retention have been developed. Fat graft enrichment with either stromal vascular fraction (SVF) cells or adipose tissue-derived stem/stromal cells (ASCs) has been investigated in several animal and human studies, and significantly improved graft retention has been reported. Improvement of graft retention and the feasibility of these techniques are equally important in evaluating the clinical relevance of cell enrichment. We conducted a systematic search of PubMed to identify studies on fat graft enrichment that used either SVF cells or ASCs, and only studies reporting volume assessment were included. A total of 38 articles (15 human and 23 animal) were included to investigate the effects of cell enrichment on graft retention as well as the feasibility and clinical relevance of cell-enriched fat grafting. Improvements in graft retention, the SVF to fat (SVF:fat) ratio, and the ASC concentration used for enrichment were emphasized. We proposed an increased retention rate greater than 1.5-fold relative to nonenriched grafts and a maximum SVF:fat ratio of 1:1 as the thresholds for clinical relevance and feasibility, respectively. Nine studies fulfilled these criteria, whereof 6 used ASCs for enrichment. We found no convincing evidence of a clinically relevant effect of SVF enrichment in humans. ASC enrichment has shown promising results in enhancing graft retention, but additional clinical trials are needed to substantiate this claim and also determine the optimal concentration of SVF cells/ASCs for enrichment. 4. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

Relationship between bicarbonate retention and bone characteristics in broiler chickens.

PubMed

Leslie, M A; Coleman, R A; Moehn, S; Ball, R O; Korver, D R

2006-11-01

Determination of the bicarbonate retention factor (BRF) is an important step during development of the indicator amino acid oxidation technique for use in a new model. A series of 4-h oxidation experiments were performed to determine the BRF of broilers aged 7, 14, 21, 28, 35, and 42 d using 4 birds per age group. A priming dose of 1.2 microCi of NaH(14)CO(3), followed by eight half-hourly doses of 1 microCi of NaH(14)CO(3) were given orally to each of 4 birds per age. The percentage of (14)C dose expired by the bird at a steady state was measured. These birds, as well as 12 additional birds matched for age and BW, were killed, and femur bone mineral density was measured by quantitative computed tomography to determine the relationship between bone development and bicarbonate retention at each age. There was a correlation (r = 0.50; P < 0.05) between total cross-sectional femur bone mineral density and bicarbonate retention at each age. A prediction equation (Y = 6.95 x 10(-2)X - 3.51 x 10(-5)X(2) + 27.58; P < 0.0001, R(2) = 0.79) where Y = bicarbonate retention and X = BW was generated to predict Y as a function of X. Bicarbonate retention values peaked at 28 d, during the stage of the most rapid bone deposition and the highest growth rate. A constant BRF was found from 1,900 to 2,700 g of BW of 35.15 +/- 1.095% (mean +/- SEM). This retention factor will allow the accurate correction of oxidation of (14)C-labeled substrates in broilers of different ages and BW in future indicator amino acid oxidation studies.

The effect of pressure and mobile phase velocity on the retention properties of small analytes and large biomolecules in ultra-high pressure liquid chromatography.

PubMed

Fekete, Szabolcs; Veuthey, Jean-Luc; McCalley, David V; Guillarme, Davy

2012-12-28

A possible complication of ultra-high pressure liquid chromatography (UHPLC) is related to the effect of pressure and mobile phase velocity on the retention properties of the analytes. In the present work, numerous model compounds have been selected including small molecules, peptides, and proteins (such as monoclonal antibodies). Two instrumental setups were considered to attain elevated pressure drops, firstly the use of a post-column restrictor capillary at low mobile phase flow rate (pure effect of pressure) and secondly the increase of mobile phase flow rate without restrictor (i.e. a combined effect of pressure and frictional heating). In both conditions, the goal was to assess differences in retention behaviour, depending on the type or character of the analyte. An important conclusion is that the effect of pressure and mobile phase velocity on retention varied in proportion with the size of the molecule and in some cases showed very different behaviour. In isocratic mode, the pure effect of pressure (experiments with a post-column restrictor capillary) induces an increase in retention by 25-100% on small molecules (MW<300 g/mol), 150% for peptides (~1.3 kDa), 800% for insulin (~6 kDa) and up to >3000% for myoglobin (~17 kDa) for an increase in pressure from 100 bar up to 1100 bar. The important effect observed for the isocratic elution of proteins is probably related to conformational changes of the protein in addition to the effect of molecular size. Working in gradient elution mode, the pressure related effects on retention were found to be less pronounced but still present (an increase of apparent retention factor between 0.2 and 2.5 was observed). Copyright © 2012 Elsevier B.V. All rights reserved.

Factors Determining Availability, Utilization and Retention of Child Health Card in Western Nepal.

PubMed

Paudel, K P; Bajracharya, D C; Karki, K; K C, A

2016-05-01

The immunization card is revised with addition of general information about child health and is later called as child health card. This card is a tool used by Health Management Information System in Nepal. It is important for tracking the records of immunization. Aim is to identify the factors determining the availability, utilization and retention of the child health card in Western Nepal. A cross sectional study was conducted among mothers having children < 24 months old from Gorkha (Western Hill) and Nawalparasi (Western Terai) districts. The sample size for the study was 600 and systematic random sampling was used to select the mothers having less than 24 months old children. Data entry and analysis was done by using SPSS. Qualitative data was analyzed by making matrix. The average age of respondents was 24 years. The majority of respondents have gained higher level education. Retention of the card was found to be 82.2%. 90.3% retention was seen among 0-12 months children age group whereas it was 74 % among12 to 24 months age group. The reasons for less retention were torn by the child/played by child (54.6%) followed by lack of proper place,unaware about importance and poor quality of card.The new child health cards were insufficient, compelling use of both new and old cards which created problem in consistency. Regarding utilization of child health card, it was found to be used for birth registration and for further studies in abroad. The areas of utilization of child health card should be broadened so that the retention of card can be increased. The main reasons for less retention of the card are torn by children and lack of the proper place.

Breast-feeding in relation to weight retention up to 36 months postpartum in the Norwegian Mother and Child Cohort Study: modification by socio-economic status?

PubMed

Brandhagen, Martin; Lissner, Lauren; Brantsaeter, Anne Lise; Meltzer, Helle Margrete; Häggkvist, Anna-Pia; Haugen, Margaretha; Winkvist, Anna

2014-07-01

We investigated the association between full breast-feeding up to 6 months as well as partial breast-feeding after 6 months and maternal weight retention at 6, 18 and 36 months after delivery in the Norwegian Mother and Child Cohort Study (MoBa), conducted by the Norwegian Institute of Public Health. Cohort study. Information on exposure and outcome was collected by questionnaire. Norway. Women at 6 months (n 49 676), 18 months (n 27 187) and 36 months (n 17 343) postpartum. Longer duration of full breast-feeding as well as partial breast-feeding was significantly related to lower weight retention at 6 months. At 18 months full breast-feeding (0-6 months) and partial breast-feeding for 12-18 months were significantly related to lower weight retention. At 36 months only full breast-feeding (0-6 months) was significantly related to lower weight retention. For each additional month of full breast-feeding, maternal weight was lowered by 0·50 kg/month at 6 months, 0·10 kg/month at 18 months and 0·14 kg/month at 36 months (adjusted for pre-pregnant BMI, pregnancy weight gain, age and parity). Partial breast-feeding resulted in 0·25 kg/month lower maternal weight at 6 months. Interactions were found between household income and full breast-feeding in relation to weight retention at 6, 18 and 36 months, indicating most benefit among women with low income. The present study supports the hypothesis that full breast-feeding contributes to lower postpartum weight retention and shows that the effect is maintained for as long as 3 years postpartum.

Effects of mineral additives on biochar formation: carbon retention, stability, and properties.

PubMed

Li, Feiyue; Cao, Xinde; Zhao, Ling; Wang, Jianfei; Ding, Zhenliang

2014-10-07

Biochar is being recognized as a promising tool for long-term carbon sequestration, and biochar with high carbon retention and strong stability is supposed to be explored for that purpose. In this study, three minerals, including kaolin, calcite (CaCO3), and calcium dihydrogen phosphate [Ca(H2PO4)2], were added to rice straw feedstock at the ratio of 20% (w/w) for biochar formation through pyrolysis treatment, aiming to improve carbon retention and stabilization in biochar. Kaolin and CaCO3 had little effect on the carbon retention, whereas Ca(H2PO4)2 increased the carbon retention by up to 29% compared to untreated biochar. Although the carbon loss from the kaolin-modified biochar with hydrogen peroxide oxidation was enhanced, CaCO3 and Ca(H2PO4)2 modification reduced the carbon loss by 18.6 and 58.5%, respectively. Moreover, all three minerals reduced carbon loss of biochar with potassium dichromate oxidation from 0.3 to 38.8%. The microbial mineralization as CO2 emission in all three modified biochars was reduced by 22.2-88.7% under aerobic incubation and 5-61% under anaerobic incubation. Enhanced carbon retention and stability of biochar with mineral treatment might be caused by the enhanced formation of aromatic C, which was evidenced by cross-polarization magic angle spinning (13)C nuclear magnetic resonance spectra and Fourier transform infrared spectroscopy analysis. Our results indicated that the three minerals, especially Ca(H2PO4)2, were effective in increasing carbon retention and strengthening biochar stabilization, which provided a novel idea that people could explore and produce the designated biochar with high carbon sequestration capacity and stability.

Application of Fragment Ion Information as Further Evidence in Probabilistic Compound Screening Using Bayesian Statistics and Machine Learning: A Leap Toward Automation.

PubMed

Woldegebriel, Michael; Zomer, Paul; Mol, Hans G J; Vivó-Truyols, Gabriel

2016-08-02

In this work, we introduce an automated, efficient, and elegant model to combine all pieces of evidence (e.g., expected retention times, peak shapes, isotope distributions, fragment-to-parent ratio) obtained from liquid chromatography-tandem mass spectrometry (LC-MS/MS/MS) data for screening purposes. Combining all these pieces of evidence requires a careful assessment of the uncertainties in the analytical system as well as all possible outcomes. To-date, the majority of the existing algorithms are highly dependent on user input parameters. Additionally, the screening process is tackled as a deterministic problem. In this work we present a Bayesian framework to deal with the combination of all these pieces of evidence. Contrary to conventional algorithms, the information is treated in a probabilistic way, and a final probability assessment of the presence/absence of a compound feature is computed. Additionally, all the necessary parameters except the chromatographic band broadening for the method are learned from the data in training and learning phase of the algorithm, avoiding the introduction of a large number of user-defined parameters. The proposed method was validated with a large data set and has shown improved sensitivity and specificity in comparison to a threshold-based commercial software package.

Effect of Technetium-99 sources on its retention in low activity waste glass

NASA Astrophysics Data System (ADS)

Luksic, Steven A.; Kim, Dong-Sang; Um, Wooyong; Wang, Guohui; Schweiger, Michael J.; Soderquist, Chuck Z.; Lukens, Wayne; Kruger, Albert A.

2018-05-01

Small-scale crucible melting tests on simulated waste glass were performed with technetium-99 (Tc-99) introduced as different species in a representative low activity waste simulant. The glass saw an increase in Tc-99 retention when TcO2•2H2O and various Tc-minerals containing reduced tetravalent Tc were used compared to tests in which pertechnetate with heptavalent Tc was used. We postulate that the increase of Tc retention is likely caused by different reaction paths for Tc incorporation into glass during early stages of melting, rather than the low volatility of reduced tetravalent Tc compounds, which has been a generally accepted idea. Additional studies are needed to clarify the exact mechanisms relevant to the effect of reduced Tc compounds on Tc incorporation into or volatilization from the glass melt.

Small Rayed Crater Ejecta Retention Age Calculated from Current Crater Production Rates on Mars

NASA Technical Reports Server (NTRS)

Calef, F. J. III; Herrick, R. R.; Sharpton, V. L.

2011-01-01

Ejecta from impact craters, while extant, records erosive and depositional processes on their surfaces. Estimating ejecta retention age (Eret), the time span when ejecta remains recognizable around a crater, can be applied to estimate the timescale that surface processes operate on, thereby obtaining a history of geologic activity. However, the abundance of sub-kilometer diameter (D) craters identifiable in high resolution Mars imagery has led to questions of accuracy in absolute crater dating and hence ejecta retention ages (Eret). This research calculates the maximum Eret for small rayed impact craters (SRC) on Mars using estimates of the Martian impactor flux adjusted for meteorite ablation losses in the atmosphere. In addition, we utilize the diameter-distance relationship of secondary cratering to adjust crater counts in the vicinity of the large primary crater Zunil.

Kidney Response to the Spectrum of Diet-Induced Acid Stress.

PubMed

Goraya, Nimrit; Wesson, Donald E

2018-05-11

Chronic ingestion of the acid (H⁺)-producing diets that are typical of developed societies appears to pose a long-term threat to kidney health. Mechanisms employed by kidneys to excrete this high dietary H⁺ load appear to cause long-term kidney injury when deployed over many years. In addition, cumulative urine H⁺ excretion is less than the cumulative increment in dietary H⁺, consistent with H⁺ retention. This H⁺ retention associated with the described high dietary H⁺ worsens as the glomerular filtration rate (GFR) declines which further exacerbates kidney injury. Modest H⁺ retention does not measurably change plasma acid⁻base parameters but, nevertheless, causes kidney injury and might contribute to progressive nephropathy. Current clinical methods do not detect H⁺ retention in its early stages but the condition manifests as metabolic acidosis as it worsens, with progressive decline of the glomerular filtration rate. We discuss this spectrum of H⁺ injury, which we characterize as “H⁺ stress”, and the emerging evidence that high dietary H⁺ constitutes a threat to long-term kidney health.

In vitro CPC retention and VSC adsorption by IPM oil droplets: possible mechanisms of action of a two phase mouthwash.

PubMed

Sterer, N; Slutzky, H; Kohavi, D; Matalon, S

2013-09-01

Two phase oil-water mouthwash has been previously shown to efficiently bind oral microorganisms, relying on their cell surface hydrophobicity. The aim of the present in vitro study was to test the cetylpyridinium chloride (CPC) retention and volatile sulfide compounds (VSCs) adsorption abilities of the oil droplets created by mixing of a two phase oil-water solution. VSC adsorption was assayed using a salivary incubation assay and garlic powder solutions, and demonstrated using microscopic sulfide assay. CPC retention was assayed by kinetic and endpoint measurement of Streptococcus salivarius outgrowth using microplate (ELISA) reader. Results showed that the isopropyl myristate (IPM) oil droplets in the two phase solutions were able to adsorb 68-80% of VSCs. CPC at a concentration of 0.05% was most affectively retained by the oil droplets showing a significantly increase in residual antibacterial activity against Streptococcus salivarius. These results taken together, suggests that VSC adsorption and CPC retention by IPM oil droplets may be two additional mechanisms in the activity of the two phase mouthwash formulation.

Accessible silanol sites - beneficial for the RP-HPLC separation of constitutional and diastereomeric azaspirovesamicol isomers.

PubMed

Wenzel, Barbara; Fischer, Steffen; Brust, Peter; Steinbach, Jörg

2010-12-10

Different RP-HPLC columns (phenyl, conventional ODS, cross-linked C(18) and special end-capped C(8) and C(18) phases) were used to investigate the separation of four basic ionizable isomers. Using ACN/20mM NH(4)OAc aq., a separation was observed exclusively on RP columns with higher silanol activity at unusual high ACN concentration, indicating cation-exchange as main retention mechanism. Using MeOH/20mM NH(4)OAc aq., another separation at low MeOH concentrations was observed on both, RP columns with higher as well as RP columns with lower silanol activity, which is mainly based on hydrophobic interactions. The isomers were also separated on a bare silica column at higher MeOH content using NH(4)OAc. Since cation-exchange governs this retention, the elution order was different compared to the RP phases. A strong retention on the silica column was observed in ACN, which could be attributed to partition processes as additional retention mechanism. Copyright © 2010 Elsevier B.V. All rights reserved.

Synthesis of Superabsorbent Polymer via Inverse Suspension Method: Effect of Carbon Filler

NASA Astrophysics Data System (ADS)

Zakaria, Munirah Ezzah Tuan; Shima Jamari, Saidatul; Ling, Yeong Yi; Ghazali, Suriati

2017-05-01

This paper studies on the effect of the addition of carbon filler towards the performance of superabsorbent polymer composite (SAPc). In this work, the SAPc was synthesized using inverse suspension polymerization method. The process involved two different solutions; dispersed phase which contains partially neutralized acrylic acid, acrylamide, APS and NN-Methylenebisacrylamide, and continuous phase which contains cyclohexane, span-80 and carbon filler (at different weight percent). The optimum SAPs and filler ratio was measured in terms of water retention in soil and characterized by Mastersizer, FTIR and SEM. Biodegradability of the polymer was determined by soil burial test and SAPc with 0.02% carbon has highest biodegradability rate. SAPc with 0.04wt% carbon showed the optimal water retention percentage among all the samples. The synthesized SAPc producing spherical shapes with parallel alignment due to the addition of carbon fiber. It can be concluded that the addition of carbon fiber able to enhance the performance of the SAP composite (SAPc).

Mass Spectrometry Based Identification of Geometric Isomers during Metabolic Stability Study of a New Cytotoxic Sulfonamide Derivatives Supported by Quantitative Structure-Retention Relationships

PubMed Central

Belka, Mariusz; Hewelt-Belka, Weronika; Sławiński, Jarosław; Bączek, Tomasz

2014-01-01

A set of 15 new sulphonamide derivatives, presenting antitumor activity have been subjected to a metabolic stability study. The results showed that besides products of biotransformation, some additional peaks occurred in chromatograms. Tandem mass spectrometry revealed the same mass and fragmentation pathway, suggesting that geometric isomerization occurred. Thus, to support this hypothesis, quantitative structure-retention relationships were applied. Human liver microsomes were used as an in vitro model of metabolism. The biotransformation reactions were tracked by liquid chromatography assay and additionally, fragmentation mass spectra were recorded. In silico molecular modeling at a semi-empirical level was conducted as a starting point for molecular descriptor calculations. A quantitative structure-retention relationship model was built applying multiple linear regression based on selected three-dimensional descriptors. The studied compounds revealed high metabolic stability, with a tendency to form hydroxylated biotransformation products. However, significant chemical instability in conditions simulating human body fluids was noticed. According to literature and MS data geometrical isomerization was suggested. The developed in sillico model was able to describe the relationship between the geometry of isomer pairs and their chromatographic retention properties, thus it supported the hypothesis that the observed pairs of peaks are most likely geometric isomers. However, extensive structural investigations are needed to fully identify isomers’ geometry. An effort to describe MS fragmentation pathways of novel chemical structures is often not enough to propose structures of potent metabolites and products of other chemical reactions that can be observed in compound solutions at early drug discovery studies. The results indicate that the relatively non-expensive and not time- and labor-consuming in sillico approach could be a good supportive tool assisting the identification of cis-trans isomers based on retention data. This methodology can be helpful during the structural identification of biotransformation and degradation products of new chemical entities - potential new drugs. PMID:24893169

Multiple arthroscopic debridement and graft retention in septic knee arthritis after ACL reconstruction: a prospective case-control study.

PubMed

Abdel-Aziz, Ahmed; Radwan, Yasser A; Rizk, Ahmed

2014-01-01

This study was undertaken to prospectively analyse, at a mean five-year follow-up, the clinical, functional, and radiographic outcomes in patients who developed postoperative acute septic knee arthritis following anterior cruciate ligament (ACL) reconstruction using hamstring autograft. We also assessed the effect of multiple arthroscopic debridement and graft retention on the functional outcomes in comparison with the matched control group. From a consecutive case series of 2,560 ACL-injured patients who were treated with arthroscopic ACL reconstruction, we report on 24 cases with postoperative septic knee arthritis. These patients were individually matched for age, sex, comorbidity, body mass index (BMI) and preinjury Tegner activity scale in a ratio of 1/1. Clinical, laboratory, synovial fluid analysis and culture were performed. Arthroscopic debridement and graft retention was done for all cases, in addition to antibiotic therapy i.v.. A detailed physical examination, KT1000 laxity testing, Lysholm knee score, Tegner activity level scale, International Knee Documentation Committee (IKDC), and Knee Injury and Osteoarthritis Outcome Score (KOOS) were completed. In all cases, treatment of infection was successful after a median of three (range one to six) repeated arthroscopic graft debridement and retention, in addition to antibiotic therapy i.v.. At an average of five years follow-up, two patients had over five millimetres manual maximum side-to-side difference in laxity. There were no significant differences between groups regarding Lysholm score, IKDC and KOOS. Median final Tegner activity score was 5.5 versus 7 in the control group (p = 0.004). Complications included graft rupture in three patients, loss of range of motion in five, Sudeck's atrophy in one and moderate joint narrowing in two. There were no recurrences of septic arthritis or bone infection. Graft retention seems not only possible but appropriate in view of the experience presented in this article for postoperative septic knee arthritis using hamstring autograft. A potential residual complication is arthrofibrosis, which deserves maximum attention.

The relationship between visual working memory and attention: retention of precise colour information in the absence of effects on perceptual selection

PubMed Central

Hollingworth, Andrew; Hwang, Seongmin

2013-01-01

We examined the conditions under which a feature value in visual working memory (VWM) recruits visual attention to matching stimuli. Previous work has suggested that VWM supports two qualitatively different states of representation: an active state that interacts with perceptual selection and a passive (or accessory) state that does not. An alternative hypothesis is that VWM supports a single form of representation, with the precision of feature memory controlling whether or not the representation interacts with perceptual selection. The results of three experiments supported the dual-state hypothesis. We established conditions under which participants retained a relatively precise representation of a parcticular colour. If the colour was immediately task relevant, it reliably recruited attention to matching stimuli. However, if the colour was not immediately task relevant, it failed to interact with perceptual selection. Feature maintenance in VWM is not necessarily equivalent with feature-based attentional selection. PMID:24018723

Simultaneous analysis and retention behavior of major isoflavonoids in Radix Puerariae lobatae and Radix Puerariae thomsonii by high performance liquid chromatography with cyclodextrins as a mobile phase modifier.

PubMed

Zeng, Aiguo; Xing, Jianfeng; Wang, Changhe; Song, Jie; Li, Cong; Yang, Xin; Yang, Guangde

2012-01-27

In order to differentiate two species of Radix Puerariae (Radix Puerariae lobatae and Radix Puerariae thomsonii) and to determine major isoflavonoids (puerarin, daidzin, daidzein and genistein) in the samples, a simple high performance liquid chromatography (HPLC) method with isocratic elution employing cyclodextrins (CDs) as mobile phase additives was developed. Various factors affecting the retention of isoflavonoids in the C(18) reversed-phase column, such as the nature of CDs, the concentration of hydroxypropyl-β-cyclodextrin (HP-β-CD) and the methanol percentage in the mobile phase, were studied. Experimental results confirmed that HP-β-CD, as a very effective mobile phase additive, could markedly reduce the retention of isoflavonoids, especially daidzein and genistein. The elution of four isoflavonoids could be achieved on a Kromasil(®) C(18) column within 56 min by using the methanol-water contained 5 mM HP-β-CD (25/75, v/v) mixture as the mobile phase. The formation of the inclusion complexes between isoflavonoids and HP-β-CD explained the modification of the retention of analytes. The apparent formation constants determined by HPLC confirmed that the stoichiometry of HP-β-CD-isoflavonoid complexes was 1:1, and the stability of the complexes depended on the size and property of isoflavonoids. The optimized method was successfully applied for the simultaneous determination of major isoflavonoids in P. lobatae and P. thomsonii samples. This work provides a useful method for the analysis of traditional Chinese herbs. Copyright © 2011 Elsevier B.V. All rights reserved.

Retention Load of Telescopic Crowns with Different Taper Angles between Cobalt-Chromium and Polyetheretherketone Made with Three Different Manufacturing Processes Examined by Pull-Off Test.

PubMed

Wagner, Christina; Stock, Veronika; Merk, Susanne; Schmidlin, Patrick R; Roos, Malgorzata; Eichberger, Marlis; Stawarczyk, Bogna

2018-02-01

To investigate the retention loads of differently fabricated secondary telescopic polyetheretherketone (PEEK) crowns on cobalt-chromium primary crowns with different tapers. Cobalt-chromium primary crowns with 0°, 1°, and 2° tapers were constructed, milled, and sintered. Corresponding secondary crowns were fabricated by milling, pressing from pellets, and pressing from granules. For these nine test groups, the pull-off tests of each crown combination were performed 20 times, and the retention loads were measured (Zwick 1445, 50 mm/min). Data were analyzed using linear regression, covariance analysis, mixed models, Kruskal-Wallis, and Mann-Whitney U-test, together with the Benferroni-Holm correction. The mixed models covariance analysis reinforced stable retention load values (p = 0.162) for each single test sequence. There was no interaction between the groups and the separation cycles (p = 0.179). Milled secondary crowns with 0° showed the lowest mean retention load values compared to all tested groups (p = 0.003) followed by those pressed form pellets with 1°. Regarding the different tapers, no effect of manufacturing method on the results was observed within 1° and 2° groups (p = 0.540; p = 0.052); however, among the 0° groups, the milled ones showed significantly the lowest retention load values (p = 0.002). Among the manufacturing methods, both pressed groups showed no impact of taper on the retention load values (p > 0.324 and p > 0.123, respectively), whereas among the milled secondary crowns, the 0° taper showed significantly lower retention load values than the 1° and 2° taper (p < 0.002). Based on these results, telescopic crowns made of PEEK seem to show stable retention load values for each test sequence; however, data with thermo-mechanical aging are still required. In addition, further developments in CAD/CAM manufacturing of PEEK materials for telescopic crowns are warranted, especially for 0°. © 2016 by the American College of Prosthodontists.

Predicting changes in hydrologic retention in an evolving semi-arid alluvial stream

USGS Publications Warehouse

Harvey, J.W.; Conklin, M.H.; Koelsch, R.S.

2003-01-01

Hydrologic retention of solutes in hyporheic zones or other slowly moving waters of natural channels is thought to be a significant control on biogeochemical cycling and ecology of streams. To learn more about factors affecting hydrologic retention, we repeated stream-tracer injections for 5 years in a semi-arid alluvial stream (Pinal Creek, Ariz.) during a period when streamflow was decreasing, channel width increasing, and coverage of aquatic macrophytes expanding. Average stream velocity at Pinal Creek decreased from 0.8 to 0.2 m/s, average stream depth decreased from 0.09 to 0.04 m, and average channel width expanded from 3 to 13 m. Modeling of tracer experiments indicated that the hydrologic retention factor (Rh), a measure of the average time that solute spends in storage per unit length of downstream transport, increased from 0.02 to 8 s/m. At the same time the ratio of cross-sectional area of storage zones to main channel cross-sectional area (As/A) increased from 0.2 to 0.8 m2/m2, and average water residence time in storage zones (ts) increased from 5 to 24 min. Compared with published data from four other streams in the US, Pinal Creek experienced the greatest change in hydrologic retention for a given change in streamflow. The other streams differed from Pinal Creek in that they experienced a change in streamflow between tracer experiments without substantial geomorphic or vegetative adjustments. As a result, a regression of hydrologic retention on streamflow developed for the other streams underpredicted the measured increases in hydrologic retention at Pinal Creek. The increase in hydrologic retention at Pinal Creek was more accurately predicted when measurements of the Darcy-Weisbach friction factor were used (either alone or in addition to streamflow) as a predictor variable. We conclude that relatively simple measurements of channel friction are useful for predicting the response of hydrologic retention in streams to major adjustments in channel morphology as well as changes in streamflow. Published by Elsevier Ltd.

Effect of transient liquid flow on retention characteristics of screen acquisition systems. [design of Space Shuttle feed system

NASA Technical Reports Server (NTRS)

Cady, E. C.

1977-01-01

A design analysis, is developed based on experimental data, to predict the effects of transient flow and pressure surges (caused either by valve or pump operation, or by boiling of liquids in warm lines) on the retention performance of screen acquisition systems. A survey of screen liquid acquisition system applications was performed to determine appropriate system environment and classification. A screen model was developed which assumed that the screen device was a uniformly distributed composite orthotropic structure, and which accounted for liquid inflow/outflow, gas ingestion quality, screen stress, and liquid spill. A series of 177 tests using 13 specimens (5 screen meshes, 4 screen device construction/backup methods, and 2 orientations) with three test fluids (isopropyl alcohol, Freon 114, and LH2) provided data which verified important features of the screen model and resulted in a design tool which could accurately predict the transient startup performance acquisition devices.

[Morphogenesis of vaginal aplasia. Therapeutic deductions].

PubMed

Minh, H N; Smadja, A; Belaisch, J

1985-01-01

On the basis of the studies of the embryogenesis of the vagina, the authors consider that malformations classically described as being partial aplasia should not be separated from the total absence of the vagina. The important feature is the association of a functioning or non functioning uterus with the absence of the vagina. They believe that it is incorrect to describe the pouch of menstrual retention associated with a functioning uterus as "haematocolpos" and that is not justified to describe the cup-shaped vestibular depression as "hemi-vagina". According to the authors, although vaginal aplasia with a functioning uterus forming a pouch of menstrual retention constitutes an absolute indication for surgery, surgery is not justified in cases of vaginal aplasia with a non functioning uterus. If Frank's method fails in these cases, the patient or the couple should be referred to a sexologist, as women with this anomaly retain a perfect femininity, although unable to conceive.

Long-term memory for the terrorist attack of September 11: Flashbulb memories, event memories, and the factors that influence their retention

PubMed Central

Hirst, William; Phelps, Elizabeth A.; Buckner, Randy L.; Budson, Andrew E.; Cuc, Alexandru; Gabrieli, John D. E.; Johnson, Marcia K.; Lyle, Keith B.; Lustig, Cindy; Mather, Mara; Meksin, Robert; Mitchell, Karen J.; Ochsner, Kevin N.; Schacter, Daniel L.; Simons, Jon S.; Vaidya, Chandan J.

2010-01-01

More than 3,000 individuals from seven US cities reported on their memories of learning of the terrorist attacks of September 11, as well as details about the attack, one week, 11 months, and/or 35 months after the assault. Some studies of flashbulb memories examining long-term retention show slowing in the rate of forgetting after a year, whereas others demonstrate accelerated forgetting. The present paper indicates that (1) the rate of forgetting for flashbulb memories and event memory (memory for details about the event itself) slows after a year, (2) the strong emotional reactions elicited by flashbulb events are remembered poorly, worse than non-emotional features such as where and from whom one learned of the attack, and (3) the content of flashbulb and event memories stabilizes after a year. The results are discussed in terms of community memory practices. PMID:19397377

Deuterium gas-driven permeation and subsequent retention in rolled tungsten foils

NASA Astrophysics Data System (ADS)

Liu, Feng; Zhou, Haishan; Li, Xiao-Chun; Xu, Yuping; An, Zhongqing; Mao, Hongmin; Xing, Wenjing; Hou, Qing; Luo, Guang-Nan

2014-12-01

Experiments concerning deuterium gas-driven permeation through rolled tungsten foils in the temperature range of 850-950 K and subsequent deuterium retention have been performed. The steady state permeation flux of deuterium is proportional to the square root of the driving pressure. The permeability of deuterium is in an order of 10-14 mol m-1 s-1 Pa-1/2 in this temperature range and the activation energy for permeation is 1.21 eV. Measurements of diffusivity are significantly affected by the driving pressure, which can be well explained by a saturable-trap model. Thermal desorption spectra of samples feature a single deuterium release peak at about 873 K. TMAP 4 modeling of this peak gives a detrapping energy of 1.70 eV, which fits the dissociation enthalpy of deuterium desorbing from the inner wall of vacancy clusters or pores in tungsten.

Robust estimation of thermodynamic parameters (ΔH, ΔS and ΔCp) for prediction of retention time in gas chromatography - Part II (Application).

PubMed

Claumann, Carlos Alberto; Wüst Zibetti, André; Bolzan, Ariovaldo; Machado, Ricardo A F; Pinto, Leonel Teixeira

2015-12-18

For this work, an analysis of parameter estimation for the retention factor in GC model was performed, considering two different criteria: sum of square error, and maximum error in absolute value; relevant statistics are described for each case. The main contribution of this work is the implementation of an initialization scheme (specialized) for the estimated parameters, which features fast convergence (low computational time) and is based on knowledge of the surface of the error criterion. In an application to a series of alkanes, specialized initialization resulted in significant reduction to the number of evaluations of the objective function (reducing computational time) in the parameter estimation. The obtained reduction happened between one and two orders of magnitude, compared with the simple random initialization. Copyright © 2015 Elsevier B.V. All rights reserved.

Remembering Left–Right Orientation of Pictures

PubMed Central

Bartlett, James C.; Gernsbacher, Morton Ann; Till, Robert E.

2015-01-01

In a study of recognition memory for pictures, we observed an asymmetry in classifying test items as “same” versus “different” in left–right orientation: Identical copies of previously viewed items were classified more accurately than left–right reversals of those items. Response bias could not explain this asymmetry, and, moreover, correct “same” and “different” classifications were independently manipulable: Whereas repetition of input pictures (one vs. two presentations) affected primarily correct “same” classifications, retention interval (3 hr vs. 1 week) affected primarily correct “different” classifications. In addition, repetition but not retention interval affected judgments that previously seen pictures (both identical and reversed) were “old”. These and additional findings supported a dual-process hypothesis that links “same” classifications to high familiarity, and “different” classifications to conscious sampling of images of previously viewed pictures. PMID:2949051

Praying Mantis Bending Core Breakoff and Retention Mechanism

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Lindermann, Randel A.

2011-01-01

Sampling cores requires the controlled breakoff of the core at a known location with respect to the drill end. An additional problem is designing a mechanism that can be implemented at a small scale, yet is robust and versatile enough to be used for a variety of core samples. The new design consists of a set of tubes (a drill tube, an outer tube, and an inner tube) and means of sliding the inner and outer tubes axially relative to each other. Additionally, a sample tube can be housed inside the inner tube for storing the sample. The inner tube fits inside the outer tube, which fits inside the drill tube. The inner and outer tubes can move axially relative to each other. The inner tube presents two lamellae with two opposing grabbing teeth and one pushing tooth. The pushing tooth is offset axially from the grabbing teeth. The teeth can move radially and their motion is controlled by the outer tube. The outer tube presents two lamellae with radial extrusions to control the inner tube lamellae motion. In breaking the core, the mechanism creates two support points (the grabbing teeth and the bit tip) and one push point. The core is broken in bending. The grabbing teeth can also act as a core retention mechanism. The praying mantis that is disclosed herein is an active core breaking/retention mechanism that requires only one additional actuator other than the drilling actuator. It can break cores that are attached to the borehole bottom as

Influence de revetements bioactifs sur les cellules endotheliales: Vers des protheses vasculaires non thrombotiques

NASA Astrophysics Data System (ADS)

Fadlallah, Hicham

Developing vascular prostheses of small diameter to replace vessels closed by atherosclerosis remains a challenge because of the risk of thrombosis. Seeding of endothelial cells, which have antithrombogenic properties, is a promising solution, but we must create surfaces which promote their adhesion and retention to resist shear stresses created by the blood flow on the surface. This master's project aimed at investigating the effect of a plasma polymerized coating rich in primary amines (called LP), with or without elements of the extracellular matrix (Fibronectin (FN) or chondroitin sulphate (CS)) on the endothelial cells and hemocompatibility of polyethylene terephthalate (PET). The adhesion, growth and retention of human umbilical vein endothelial cells (HUVECs) on PET and LP, in the presence and absence of FN or CS, have been studied. In addition, platelet adhesion on different surfaces was evaluated by a perfusion test with whole blood, platelets being previously labeled with rhodamine. Finally a double fluorescent labeling (using Cellview Maroon to mark the HUVECs and CD61 antibody for platelets) was developed to study the retention of endothelial cells, under blood flow and verify their non thrombogenic character. The results obtained show that both the LP coating and the adsorbed FN, strongly increase both the cellular adhesion and growth on PET; however they have no additional effect when the two are combined. They also augment cellular retention to surface, but this remains incomplete. Moreover we observed that the plasma coating (LP) greatly increases the thrombogenicity of the surface, with strong platelet adhesion and activation. This thrombogenicity is extremely reduced when endothelial cells cover the surface, but cell loss under the effect of shear produced by the perfusion creates significant areas of platelet adhesion. The grafting of CS on LP also permits good HUVECs adhesion, growth and retention under shear stress on HUVEC, with no difference from the LP alone. In addition, the CS sharply decreases the platelet adhesion, which is found below the value observed for PET. The double cell labeling also showed that cells adhered on LP+CS has an anti-thrombotic phenotype and can resist blood flow. These studies suggest that a coating of CS is a promising strategy for vascular prosthesis given the combination of the good adhesion of endothelial cells and the low thrombogenicity of the underlying surface. Keywords: vascular prostheses, polymers, bioactive coating, thrombogenicity, HUVECs.

Final Environmental Assessment: Evaluation of Prescribed Burning for Ecological Restoration and Forest Management

DTIC Science & Technology

2005-01-01

north. Most of the birds winter in western parts of the state, particularly at Reelfoot Lake , and at Dale Hollow Reservoir. However, bald eagles may...Units Final Environmental Assessment d Tims Ford Lake Crumpton Creek Sinking Pond Retention Reservoir ormandy Lake Woods Reservoir P:\\ARNOLDAFB...occur in long narrow areas on first bottoms along streams (USDA SCS, 1949). 3.3.3 Hydrology Hydrological features consist of surface waters ( lakes

An Investigation of Knowledge Transfer and Retention in a Government Procurement Office

DTIC Science & Technology

2009-03-01

knowledge management. Lubit tells how tacit knowledge is the true source of sustaining a competitive advantage and features rationale for the importance to...reviewed by the Institutional Review Board for suitability of human experimentation and have been approved in accordance with 32 CFR 219, DoD 3216.2, and...with Stochastic Turnover. Eurpoean Journal of Operational Reserch , 169-189. Camm, F. (2003). Adapting Best Commercial Practices to Defense. RAND

A validation study concerning the effects of interview content, retention interval, and grade on children's recall accuracy for dietary intake and/or physical activity.

PubMed

Baxter, Suzanne D; Hitchcock, David B; Guinn, Caroline H; Vaadi, Kate K; Puryear, Megan P; Royer, Julie A; McIver, Kerry L; Dowda, Marsha; Pate, Russell R; Wilson, Dawn K

2014-12-01

Practitioners and researchers are interested in assessing children's dietary intake and physical activity together to maximize resources and minimize subject burden. Our aim was to investigate differences in dietary and/or physical activity recall accuracy by content (diet only; physical activity only; diet and physical activity), retention interval (same-day recalls in the afternoon; previous-day recalls in the morning), and grade (third; fifth). Children (n=144; 66% African American, 13% white, 12% Hispanic, 9% other; 50% girls) from four schools were randomly selected for interviews about one of three contents. Each content group was equally divided by retention interval, each equally divided by grade, each equally divided by sex. Information concerning diet and physical activity at school was validated with school-provided breakfast and lunch observations, and accelerometry, respectively. Dietary accuracy measures were food-item omission and intrusion rates, and kilocalorie correspondence rate and inflation ratio. Physical activity accuracy measures were absolute and arithmetic differences for moderate to vigorous physical activity minutes. For each accuracy measure, linear models determined effects of content, retention interval, grade, and their two-way and three-way interactions; ethnicity and sex were control variables. Content was significant within four interactions: intrusion rate (content×retention-interval×grade; P=0.0004), correspondence rate (content×grade; P=0.0004), inflation ratio (content×grade; P=0.0104), and arithmetic difference (content×retention-interval×grade; P=0.0070). Retention interval was significant for correspondence rate (P=0.0004), inflation ratio (P=0.0014), and three interactions: omission rate (retention-interval×grade; P=0.0095), intrusion rate, and arithmetic difference (both already mentioned). Grade was significant for absolute difference (P=0.0233) and five interactions mentioned. Content effects depended on other factors. Grade effects were mixed. Dietary accuracy was better with same-day than previous-day retention interval. Results do not support integrating dietary intake and physical activity in children's recalls, but do support using shorter rather than longer retention intervals to yield more accurate dietary recalls. Additional validation studies need to clarify age effects and identify evidence-based practices to improve children's accuracy for recalling dietary intake and/or physical activity. Copyright © 2014 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Assessing Chemical Retention Process Controls in Ponds

NASA Astrophysics Data System (ADS)

Torgersen, T.; Branco, B.; John, B.

2002-05-01

Small ponds are a ubiquitous component of the landscape and have earned a reputation as effective chemical retention devices. The most common characterization of pond chemical retention is the retention coefficient, Ri= ([Ci]inflow-[Ci] outflow)/[Ci]inflow. However, this parameter varies widely in one pond with time and among ponds. We have re-evaluated literature reported (Borden et al., 1998) monthly average retention coefficients for two ponds in North Carolina. Employing a simple first order model that includes water residence time, the first order process responsible for species removal have been separated from the water residence time over which it acts. Assuming the rate constant for species removal is constant within the pond (arguable at least), the annual average rate constant for species removal is generated. Using the annual mean rate constant for species removal and monthly water residence times results in a significantly enhanced predictive capability for Davis Pond during most months of the year. Predictive ability remains poor in Davis Pond during winter/unstratified periods when internal loading of P and N results in low to negative chemical retention. Predictive ability for Piedmont Pond (which has numerous negative chemical retention periods) is improved but not to the same extent as Davis Pond. In Davis Pond, the rate constant for sediment removal (each month) is faster than the rate constant for water and explains the good predictability for sediment retention. However, the removal rate constant for P and N is slower than the removal rate constant for sediment (longer water column residence time for P,N than for sediment). Thus sedimentation is not an overall control on nutrient retention. Additionally, the removal rate constant for P is slower than for TOC (TOC is not the dominate removal process for P) and N is removed slower than P (different in pond controls). For Piedmont Pond, sediment removal rate constants are slower than the removal rate constant for water indicating significant sediment resuspension episodes. It appears that these sediment resuspension events are aperiodic and control the loading and the chemical retention capability of Piedmont Pond for N,P,TOC. These calculated rate constants reflect the differing internal loading processes for each component and suggest means and mechanisms for the use of ponds in water quality management.

Predicting colloid transport through saturated porous media: A critical review

NASA Astrophysics Data System (ADS)

Molnar, Ian L.; Johnson, William P.; Gerhard, Jason I.; Willson, Clinton S.; O'Carroll, Denis M.

2015-09-01

Understanding and predicting colloid transport and retention in water-saturated porous media is important for the protection of human and ecological health. Early applications of colloid transport research before the 1990s included the removal of pathogens in granular drinking water filters. Since then, interest has expanded significantly to include such areas as source zone protection of drinking water systems and injection of nanometals for contaminated site remediation. This review summarizes predictive tools for colloid transport from the pore to field scales. First, we review experimental breakthrough and retention of colloids under favorable and unfavorable colloid/collector interactions (i.e., no significant and significant colloid-surface repulsion, respectively). Second, we review the continuum-scale modeling strategies used to describe observed transport behavior. Third, we review the following two components of colloid filtration theory: (i) mechanistic force/torque balance models of pore-scale colloid trajectories and (ii) approximating correlation equations used to predict colloid retention. The successes and limitations of these approaches for favorable conditions are summarized, as are recent developments to predict colloid retention under the unfavorable conditions particularly relevant to environmental applications. Fourth, we summarize the influences of physical and chemical heterogeneities on colloid transport and avenues for their prediction. Fifth, we review the upscaling of mechanistic model results to rate constants for use in continuum models of colloid behavior at the column and field scales. Overall, this paper clarifies the foundation for existing knowledge of colloid transport and retention, features recent advances in the field, critically assesses where existing approaches are successful and the limits of their application, and highlights outstanding challenges and future research opportunities. These challenges and opportunities include improving mechanistic descriptions, and subsequent correlation equations, for nanoparticle (i.e., Brownian particle) transport through soil, developing mechanistic descriptions of colloid retention in so-called "unfavorable" conditions via methods such as the "discrete heterogeneity" approach, and employing imaging techniques such as X-ray tomography to develop realistic expressions for grain topology and mineral distribution that can aid the development of these mechanistic approaches.

Transport and Transformation of Selenium and Other Constituents of Flue-Gas Desulfurization Wastewater in Water-Saturated Soil Materials.

PubMed

Galkaduwa, Madhubhashini B; Hettiarachchi, Ganga M; Kluitenberg, Gerard J; Hutchinson, Stacy L; Davis, Lawrence; Erickson, Larry E

2017-03-01

Constructed wetland treatment systems are used to remove selenium (Se) from flue-gas desulfurization (FGD) wastewater (WW). However, direct confirmation of the mechanism responsible for FGD WW Se retention in soil is lacking. A laboratory-based soil column study was performed to develop an evidence-based mechanism of Se retention and to study the behavior and the retention capacity of FGD WW constituents in water-saturated soil. A deoxygenated 1:1 mixture of FGD WW and raw water was delivered to the columns bottom-up at a flux of 1.68 cm d for 100 d. Some of the columns were flushed with the raw water at the same rate for an additional 100 d. Column effluent was analyzed for constituents of concern. Results showed a complete retention of FGD WW Se in the soil materials. Boron and fluorine were partially retained; however, sulfur, sodium, and chlorine retention was poor, agreeing with field observations. The FGD WW Se was retained in soil near the inlet end of the columns, indicating its limited mobility under reduced conditions. Sequential extraction procedure revealed that retained Se was mainly sequestered as stable/residual forms. Bulk- and micro-X-ray absorption near-edge structure spectroscopy confirmed that Se was mainly retained as reduced/stable species [Se(IV), organic Se, and Se(0)]. This study provides direct evidence for FGD WW Se retention in water-saturated soil via the transformation of oxidized Se into reduced/stable forms. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

An Alternative Prosthetic Approach for Rehabilitation of Two Edentulous Maxillectomy Patients: Clinical Report.

PubMed

Yenisey, Murat; Külünk, Şafak; Kaleli, Necati

2017-07-01

Obturator prosthesis is a common treatment method for maxillectomy patients for maintaining their oronasal separation and resuming their social lives. After tumor resection, the remaining anatomical structures have a significant effect on prosthesis retention. The present study describes the rehabilitation of two maxillectomy patients after cancer surgery using a prosthesis consisting of a denture and a special retentive obturator that is positioned in the anatomical undercuts of the nasal cavity. These patients have undergone total and subtotal maxillectomy surgery after the diagnosis of squamous cell carcinoma. The systemic and local health status of the total maxillectomy patient was not suitable for zygomatic implant surgery. Only one osseointegrated dental implant was placed into the left maxillary tuberosity area in the subtotal maxillectomy patient. In addition, the quality, vertical height, and horizontal width of the remaining bone structures in the maxilla limited the use of osseointegrated dental implants. Mechanical prosthesis retention was provided using a multiunit retentive mechanism composed of an orthodontic forsus fatigue resistant device (OFFRD), two Herbst appliances, and an acrylic piece associated with healthy keratinized mucosa. The OFFRD could easily apply a consistent force and push the acrylic pieces toward the retentive undercut under the control of the two Herbst appliances. Two OFFRD units in different directions were designed for the total maxillectomy patient, while only one OFFRD unit was placed on the opposite side of the osseointegrated implant in the subtotal maxillectomy patient. A sufficient retention was obtained for both patients. The patients were satisfied, and no major complications were observed in periodic controls. © 2017 by the American College of Prosthodontists.

An in vitro study on the retentive strength of orthodontic bands cemented with CPP-ACP-containing GIC

NASA Astrophysics Data System (ADS)

Heravi, Farzin; Bagheri, Hossein; Rangrazi, Abdolrasoul; Mojtaba Zebarjad, Seyed

2016-12-01

Caries and white spot lesions around orthodontic bands are well known occurrences in fixed orthodontic treatment. There are several methods to overcome these problems. One of these includes modification of the band cement with remineralizing agents such as casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). However, it should be evaluated that the cement modification has no significant negative effects on the retentive strength of the cemented orthodontic bands. In a continuation of our previous studies on the effects of the addition of CPP-ACP on the mechanical properties of luting and lining glass ionomer cement (GIC), this study aimed to investigate the retentive strength of orthodontic bands cemented with CPP-ACP containing GIC. Sixty extracted human pre molars teeth were embedded in acrylic resin and randomly divided into two groups of 30 specimens. In group 1, bands were cemented to the tooth with a GIC. In group 2, CPP-ACP (1.56% w/w) was added to the GIC before cementation. The retentive strength of each groups was determined with a universal testing machine. Further, the amount of cement remaining on the tooth surface was evaluated under a stereomicroscope, and the adhesive remnant index (ARI) score was determined. Results of this study showed that there were no significant differences between the groups in retentive strength and ARI score. In conclusion, modification of GIC with 1.56% w/w CPP-ACP had no negative effects on the retentive strength of the bands so can be used during fixed orthodontic treatment.

Postoperative Urinary Retention and Urinary Tract Infections Predict Midurethral Sling Mesh Complications.

PubMed

Punjani, Nahid; Winick-Ng, Jennifer; Welk, Blayne

2017-01-01

To determine if postoperative urinary retention and urinary tract infections (UTIs) were predictors of future mesh complications requiring surgical intervention after midurethral sling (MUS). Administrative data in Ontario, Canada, between 2002 and 2013 were used to identify all women who underwent a mesh-based MUS. The primary outcome was revision of the transvaginal mesh sling (including mesh removal/erosion/fistula, or urethrolysis). Two potential risk factors were analyzed: postoperative retention (within 30 days of procedure) and number of postoperative emergency room visits or hospital admissions for UTI symptoms. A total of 59,556 women had a MUS, of which 1598 (2.7%) required revision surgery. Of the 2025 women who presented to the emergency room or were admitted to hospital for postoperative retention, 212 (10.5%) required operative mesh revision. Of the 11,747 patients who had at least one postoperative UTI, 366 (3.1%) patients required operative mesh revision. In adjusted analysis, postoperative retention was significantly predictive of future reoperation (hazard ratio [HR] 3.46, 95% confidence interval [CI] 2.97-4.02), and this difference persisted when urethrolysis was excluded as a reason for sling revision (HR 3.08, 95% CI 2.62-3.63). Similarly, in adjusted analysis, each additional postoperative hospital visit for UTI symptoms increased the risk for surgical intervention for mesh complications (HR 1.74, 95% CI 1.61-1.87). Postoperative urinary retention and hospital presentation for UTI symptoms are associated with an increased risk of reoperation for MUS complications. These patients should be followed and investigated for mesh complications when appropriate. Copyright © 2016 Elsevier Inc. All rights reserved.

Chemometric Analysis of Gas Chromatography – Mass Spectrometry Data using Fast Retention Time Alignment via a Total Ion Current Shift Function

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

Nadeau, Jeremy S.; Wright, Bob W.; Synovec, Robert E.

2010-04-15

A critical comparison of methods for correcting severely retention time shifted gas chromatography-mass spectrometry (GC-MS) data is presented. The method reported herein is an adaptation to the Piecewise Alignment Algorithm to quickly align severely shifted one-dimensional (1D) total ion current (TIC) data, then applying these shifts to broadly align all mass channels throughout the separation, referred to as a TIC shift function (SF). The maximum shift varied from (-) 5 s in the beginning of the chromatographic separation to (+) 20 s toward the end of the separation, equivalent to a maximum shift of over 5 peak widths. Implementing themore » TIC shift function (TIC SF) prior to Fisher Ratio (F-Ratio) feature selection and then principal component analysis (PCA) was found to be a viable approach to classify complex chromatograms, that in this study were obtained from GC-MS separations of three gasoline samples serving as complex test mixtures, referred to as types C, M and S. The reported alignment algorithm via the TIC SF approach corrects for large dynamic shifting in the data as well as subtle peak-to-peak shifts. The benefits of the overall TIC SF alignment and feature selection approach were quantified using the degree-of-class separation (DCS) metric of the PCA scores plots using the type C and M samples, since they were the most similar, and thus the most challenging samples to properly classify. The DCS values showed an increase from an initial value of essentially zero for the unaligned GC-TIC data to a value of 7.9 following alignment; however, the DCS was unchanged by feature selection using F-Ratios for the GC-TIC data. The full mass spectral data provided an increase to a final DCS of 13.7 after alignment and two-dimensional (2D) F-Ratio feature selection.« less

Is the gravity effect of radiographic anatomic features enough to justify stone clearance or fragments retention following extracorporeal shock wave lithotripsy (SWL).

PubMed

Mustafa, Mahmoud

2012-08-01

We determined whether the gravity effect of radiographic anatomic features on the preoperative urography (IVP) are enough to predict fragments clearance after shock wave lithotripsy (SWL). A Total of 282 patients with mean age 45.8 ± 13.2 years (189 male, 93 female), who underwent SWL due to renal calculi between October 2005 and August 2009 were enrolled. The mean calculi load was 155.72 ± 127.66 mm². The patients were stratified into three groups: patients with pelvis calculi (group 1); patients with upper or middle pole calculi (group 2) and patients with lower pole calculi (group 3). Three angles on the pretreatment IVP were measured: the inner angle between the axis of the lower pole infundibular and ureteropelvic axis (angle I); the inner angle between the lower pole infundibular axis and main axis of pelvis-ureteropelvic (UP) junction point (angle II) and the inner angle between the lower pole infundibular axis and perpendicular line (angle III). Multivariate analysis was used to define the significant predictors of stone clearance. The overall success rate was 85.81%. All angles, sessions number, shock waves number and stone burden were significant predictors of success in patients in group 1. However, in group 2 only angle II and in group 3 angles I and II had significant effect on stone clearance. Radiographic anatomic features have significant role in determining the stone-free rate following satisfactory fragmentation of renal stones with SWL. The measurement of infundibulopelvic angle in different manner helps to predict the stone-free status in patients with renal calculi located not only in lower pole, but also in renal pelvis and upper or middle pole. Gravity effect is not enough to justify the significant influence of the radiographic anatomic features on the stone clearance and fragments retention after SWL.

Progenitor cell dynamics in the Newt Telencephalon during homeostasis and neuronal regeneration.

PubMed

Kirkham, Matthew; Hameed, L Shahul; Berg, Daniel A; Wang, Heng; Simon, András

2014-04-08

The adult newt brain has a marked neurogenic potential and is highly regenerative. Ventricular, radial glia-like ependymoglia cells give rise to neurons both during normal homeostasis and after injury, but subpopulations among ependymoglia cells have not been defined. We show here that a substantial portion of GFAP(+) ependymoglia cells in the proliferative hot spots of the telencephalon has transit-amplifying characteristics. In contrast, proliferating ependymoglia cells, which are scattered along the ventricular wall, have stem cell features in terms of label retention and insensitivity to AraC treatment. Ablation of neurons remodels the proliferation dynamics and leads to de novo formation of regions displaying features of neurogenic niches, such as the appearance of cells with transit-amplifying features and proliferating neuroblasts. The results have implication both for our understanding of the evolutionary diversification of radial glia cells as well as the processes regulating neurogenesis and regeneration in the adult vertebrate brain.

Effect of Technetium-99 sources on its retention in low activity waste glass

DOE PAGES

Luksic, Steven A.; Kim, Dong Sang; Um, Wooyong; ...

2018-03-02

Small-scale crucible melting tests on simulated waste glass were performed with technetium-99 (Tc-99) introduced as different species in a representative low activity waste simulant. The glass saw an increase in Tc-99 retention when TcO 2∙2H 2O and various Tc-minerals containing reduced tetravalent Tc were used compared to tests in which pertechnetate with heptavalent Tc was used. Here, we postulate that the increase of Tc retention is likely caused by different reaction paths for Tc incorporation into glass during early stages of melting, rather than the low volatility of reduced tetravalent Tc compounds, which has been a generally accepted idea. Finally,more » additional studies are needed to clarify the exact mechanisms relevant to the effect of reduced Tc compounds on Tc incorporation into or volatilization from the glass melt.« less

Effect of Technetium-99 sources on its retention in low activity waste glass

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

Luksic, Steven A.; Kim, Dong-Sang; Um, Wooyong

Small-scale crucible melting tests on simulated waste glass were performed with technetium-99 (Tc-99) introduced as different species in a representative low activity waste simulant. The glass saw an increase in Tc-99 retention when TcO2∙2H2O and various Tc-minerals containing reduced tetravalent Tc were used compared to tests in which pertechnetate with hexavalent Tc was used. We postulate that the increase of Tc retention is likely caused by different reaction paths for Tc incorporation into glass during early stages of melting, rather than the low volatility of reduced tetravalent Tc compounds, which has been a generally accepted idea. Additional studies are neededmore » to clarify the exact mechanisms relevant to the effect of reduced Tc compounds on Tc incorporation into or volatilization from glass melt.« less

Effect of Technetium-99 sources on its retention in low activity waste glass

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

Luksic, Steven A.; Kim, Dong Sang; Um, Wooyong

Small-scale crucible melting tests on simulated waste glass were performed with technetium-99 (Tc-99) introduced as different species in a representative low activity waste simulant. The glass saw an increase in Tc-99 retention when TcO 2∙2H 2O and various Tc-minerals containing reduced tetravalent Tc were used compared to tests in which pertechnetate with heptavalent Tc was used. Here, we postulate that the increase of Tc retention is likely caused by different reaction paths for Tc incorporation into glass during early stages of melting, rather than the low volatility of reduced tetravalent Tc compounds, which has been a generally accepted idea. Finally,more » additional studies are needed to clarify the exact mechanisms relevant to the effect of reduced Tc compounds on Tc incorporation into or volatilization from the glass melt.« less

Effect of Technetium-99 sources on its retention in low activity waste glass

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

Luksic, Steven A.; Kim, Dong-Sang; Um, Wooyong

© 2018 Small-scale crucible melting tests on simulated waste glass were performed with technetium-99 (Tc-99) introduced as different species in a representative low activity waste simulant. The glass saw an increase in Tc-99 retention when TcO 2 ∙2H 2 O and various Tc-minerals containing reduced tetravalent Tc were used compared to tests in which pertechnetate with heptavalent Tc was used. We postulate that the increase of Tc retention is likely caused by different reaction paths for Tc incorporation into glass during early stages of melting, rather than the low volatility of reduced tetravalent Tc compounds, which has been a generallymore » accepted idea. Additional studies are needed to clarify the exact mechanisms relevant to the effect of reduced Tc compounds on Tc incorporation into or volatilization from the glass melt.« less

The Value of Animations in Biology Teaching: A Study of Long-Term Memory Retention

PubMed Central

2007-01-01

Previous work has established that a narrated animation is more effective at communicating a complex biological process (signal transduction) than the equivalent graphic with figure legend. To my knowledge, no study has been done in any subject area on the effectiveness of animations versus graphics in the long-term retention of information, a primary and critical issue in studies of teaching and learning. In this study, involving 393 student responses, three different animations and two graphics—one with and one lacking a legend—were used to determine the long-term retention of information. The results show that students retain more information 21 d after viewing an animation without narration compared with an equivalent graphic whether or not that graphic had a legend. Students' comments provide additional insight into the value of animations in the pedagogical process, and suggestions for future work are proposed. PMID:17785404

The value of animations in biology teaching: a study of long-term memory retention.

PubMed

O'Day, Danton H

2007-01-01

Previous work has established that a narrated animation is more effective at communicating a complex biological process (signal transduction) than the equivalent graphic with figure legend. To my knowledge, no study has been done in any subject area on the effectiveness of animations versus graphics in the long-term retention of information, a primary and critical issue in studies of teaching and learning. In this study, involving 393 student responses, three different animations and two graphics-one with and one lacking a legend-were used to determine the long-term retention of information. The results show that students retain more information 21 d after viewing an animation without narration compared with an equivalent graphic whether or not that graphic had a legend. Students' comments provide additional insight into the value of animations in the pedagogical process, and suggestions for future work are proposed.

Learning Efficiency: Identifying Individual Differences in Learning Rate and Retention in Healthy Adults.

PubMed

Zerr, Christopher L; Berg, Jeffrey J; Nelson, Steven M; Fishell, Andrew K; Savalia, Neil K; McDermott, Kathleen B

2018-06-01

People differ in how quickly they learn information and how long they remember it, yet individual differences in learning abilities within healthy adults have been relatively neglected. In two studies, we examined the relation between learning rate and subsequent retention using a new foreign-language paired-associates task (the learning-efficiency task), which was designed to eliminate ceiling effects that often accompany standardized tests of learning and memory in healthy adults. A key finding was that quicker learners were also more durable learners (i.e., exhibited better retention across a delay), despite studying the material for less time. Additionally, measures of learning and memory from this task were reliable in Study 1 ( N = 281) across 30 hr and Study 2 ( N = 92; follow-up n = 46) across 3 years. We conclude that people vary in how efficiently they learn, and we describe a reliable and valid method for assessing learning efficiency within healthy adults.

Effect of Technetium-99 sources on its retention in low activity waste glass

DOE PAGES

Luksic, Steven A.; Kim, Dong-Sang; Um, Wooyong; ...

2018-05-01

© 2018 Small-scale crucible melting tests on simulated waste glass were performed with technetium-99 (Tc-99) introduced as different species in a representative low activity waste simulant. The glass saw an increase in Tc-99 retention when TcO 2 ∙2H 2 O and various Tc-minerals containing reduced tetravalent Tc were used compared to tests in which pertechnetate with heptavalent Tc was used. We postulate that the increase of Tc retention is likely caused by different reaction paths for Tc incorporation into glass during early stages of melting, rather than the low volatility of reduced tetravalent Tc compounds, which has been a generallymore » accepted idea. Additional studies are needed to clarify the exact mechanisms relevant to the effect of reduced Tc compounds on Tc incorporation into or volatilization from the glass melt.« less

Rack assembly for mounting solar modules

DOEpatents

Plaisted, Joshua Reed; West, Brian

2010-12-28

A rack assembly is provided for mounting solar modules over an underlying body. The rack assembly may include a plurality of rail structures that are arrangeable over the underlying body to form an overall perimeter for the rack assembly. One or more retention structures may be provided with the plurality of rail structures, where each retention structure is configured to support one or more solar modules at a given height above the underlying body. At least some of the plurality of rail structures are adapted to enable individual rail structures o be sealed over the underlying body so as to constrain air flow underneath the solar modules. Additionally, at least one of (i) one or more of the rail structures, or (ii) the one or more retention structures are adjustable so as to adapt the rack assembly to accommodate solar modules of varying forms or dimensions.

Rack assembly for mounting solar modules

DOEpatents

Plaisted, Joshua Reed; West, Brian

2012-09-04

A rack assembly is provided for mounting solar modules over an underlying body. The rack assembly may include a plurality of rail structures that are arrangeable over the underlying body to form an overall perimeter for the rack assembly. One or more retention structures may be provided with the plurality of rail structures, where each retention structure is configured to support one or more solar modules at a given height above the underlying body. At least some of the plurality of rail structures are adapted to enable individual rail structures to be sealed over the underlying body so as to constrain air flow underneath the solar modules. Additionally, at least one of (i) one or more of the rail structures, or (ii) the one or more retention structures are adjustable so as to adapt the rack assembly to accommodate solar modules of varying forms or dimensions.

Rack assembly for mounting solar modules

DOEpatents

Plaisted, Joshua Reed; West, Brian

2014-06-10

A rack assembly is provided for mounting solar modules over an underlying body. The rack assembly may include a plurality of rail structures that are arrangeable over the underlying body to form an overall perimeter for the rack assembly. One or more retention structures may be provided with the plurality of rail structures, where each retention structure is configured to support one or more solar modules at a given height above the underlying body. At least some of the plurality of rail structures are adapted to enable individual rail structures o be sealed over the underlying body so as to constrain air flow underneath the solar modules. Additionally, at least one of (i) one or more of the rail structures, or (ii) the one or more retention structures are adjustable so as to adapt the rack assembly to accommodate solar modules of varying forms or dimensions.

Discrepancies between explicit and implicit self-esteem: implications for mate retention strategies and perceived infidelity.

PubMed

Zeigler-Hill, Virgil; Fulton, Jessica J; McLemore, Chandler

2012-01-01

The purpose of the present study was to examine whether the association between explicit self-esteem and relationship outcomes was moderated by implicit self-esteem. This was accomplished by asking 210 undergraduates who were currently involved in romantic relationships to complete measures of their explicit self-esteem, implicit self-esteem, mate retention strategies, and likelihood of future infidelity. Implicit self-esteem was found to moderate the association between high explicit self-esteem and relationship outcomes for male participants such that men with discrepant high self-esteem (i.e., high explicit self-esteem but low implicit self-esteem) reported less use of mate retention strategies and perceived a greater likelihood of future infidelity in their relationships during the next year. These findings provide additional support for the idea that fragile self-esteem may have consequences for the manner in which individuals perceive their relationships.

Retention mechanisms for ER and Golgi membrane proteins.

PubMed

Gao, Caiji; Cai, Yi; Wang, Yejun; Kang, Byung-Ho; Aniento, Fernando; Robinson, David G; Jiang, Liwen

2014-08-01

Unless there are mechanisms to selectively retain membrane proteins in the endoplasmic reticulum (ER) or in the Golgi apparatus, they automatically proceed downstream to the plasma or vacuole membranes. Two types of coat protein complex I (COPI)-interacting motifs in the cytosolic tails of membrane proteins seem to facilitate membrane retention in the early secretory pathway of plants: a dilysine (KKXX) motif (which is typical of p24 proteins) for the ER and a KXE/D motif (which occurs in the Arabidopsis endomembrane protein EMP12) for the Golgi apparatus. The KXE/D motif is highly conserved in all eukaryotic EMPs and is additionally present in hundreds of other proteins of unknown subcellular localization and function. This novel signal may represent a new general mechanism for Golgi targeting and the retention of polytopic integral membrane proteins. Copyright © 2014 Elsevier Ltd. All rights reserved.

48 CFR 1852.227-11 - Patent Rights-Retention by the Contractor (Short Form).

Code of Federal Regulations, 2011 CFR

2011-10-01

... Technology Reporting Web site http://invention.nasa.gov. (End of addition) (f)(5) The Contractor shall... of tier, for experimental, developmental, research, design, or engineering work to be performed by...