Gamow-Teller Strength Distributions for pf-shell Nuclei and its Implications in Astrophysics

NASA Astrophysics Data System (ADS)

Rahman, M.-U.; Nabi, J.-U.

2009-08-01

The {pf}-shell nuclei are present in abundance in the pre-supernova and supernova phases and these nuclei are considered to play an important role in the dynamics of core collapse supernovae. The B(GT) values are calculated for the {pf}-shell nuclei 55Co and 57Zn using the pn-QRPA theory. The calculated B(GT) strengths have differences with earlier reported shell model calculations, however, the results are in good agreement with the experimental data. These B(GT) strengths are used in the calculations of weak decay rates which play a decisive role in the core-collapse supernovae dynamics and nucleosynthesis. Unlike previous calculations the so-called Brink's hypothesis is not assumed in the present calculation which leads to a more realistic estimate of weak decay rates. The electron capture rates are calculated over wide grid of temperature ({0.01} × 109 - 30 × 109 K) and density (10-1011 g-cm-3). Our rates are enhanced compared to the reported shell model rates. This enhancement is attributed partly to the liberty of selecting a huge model space, allowing consideration of many more excited states in the present electron capture rates calculations.

PF-WFS Shell Inspection Update December 2016

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

Vigil, Anthony Eugene; Ledoux, Reina Rebecca; Gonzales, Antonio R.

Since the last project update in FY16:Q2, PF-WFS personnel have advanced in understanding of shell inspection on Coordinate Measuring Machines {CMM} and refined the PF-WFS process to the point it was decided to convert shell inspection from the Sheffield #1 gage to Lietz CM Ms. As a part of introspection on the quality of this process many sets of data have been reviewed and analyzed. This analysis included Sheffield to CMM comparisons, CMM inspection repeatability, fixturing differences, quality check development, probing approach changes. This update report will touch on these improvements that have built the confidence in this process tomore » mainstream it inspecting shells. In addition to the CMM programming advancements, the continuation in refinement of input and outputs for the CMM program has created an archiving scheme, input spline files, an output metafile, and inspection report package. This project will continue to mature. Part designs may require program modifications to accommodate "new to this process" part designs. Technology limitations tied to security and performance are requiring possible changes to computer configurations to support an automated process.« less

Complete attenuation of genetically engineered Plasmodium falciparum sporozoites in human subjects.

PubMed

Kublin, James G; Mikolajczak, Sebastian A; Sack, Brandon K; Fishbaugher, Matt E; Seilie, Annette; Shelton, Lisa; VonGoedert, Tracie; Firat, Melike; Magee, Sara; Fritzen, Emma; Betz, Will; Kain, Heather S; Dankwa, Dorender A; Steel, Ryan W J; Vaughan, Ashley M; Noah Sather, D; Murphy, Sean C; Kappe, Stefan H I

2017-01-04

Immunization of humans with whole sporozoites confers complete, sterilizing immunity against malaria infection. However, achieving consistent safety while maintaining immunogenicity of whole parasite vaccines remains a formidable challenge. We generated a genetically attenuated Plasmodium falciparum (Pf) malaria parasite by deleting three genes expressed in the pre-erythrocytic stage (Pf p52 - /p36 - /sap1 - ). We then tested the safety and immunogenicity of the genetically engineered (Pf GAP3KO) sporozoites in human volunteers. Pf GAP3KO sporozoites were delivered to 10 volunteers using infected mosquito bites with a single exposure consisting of 150 to 200 bites per subject. All subjects remained blood stage-negative and developed inhibitory antibodies to sporozoites. GAP3KO rodent malaria parasites engendered complete, protracted immunity against infectious sporozoite challenge in mice. The results warrant further clinical testing of Pf GAP3KO and its potential development into a vaccine strain. Copyright © 2017, American Association for the Advancement of Science.

0ħω MEC effect on M1 properties of middle pf-shell nuclei

NASA Astrophysics Data System (ADS)

Nakada, H.; Sebe, T.

1994-09-01

M1 properties of middle pf-shell nuclei are studied within the framework of a large-scale shell-model calculation, by including two-body operators originating from the MEC effect within the 0ħω space. This MEC effect tends to enhance the M1 matrix elements slightly. However, the 0ħω MEC effect does not change the previous results so much, which have shown notable quenching in the magnetic moments of 55Co and 57Ni due to the 0ħω CP effect, while the 0ħω MEC effect should be kept track of in discussing the M1 properties with ⪅ 10% accuracy.

Deriving the nuclear shell model from first principles

NASA Astrophysics Data System (ADS)

Barrett, Bruce R.; Dikmen, Erdal; Vary, James P.; Maris, Pieter; Shirokov, Andrey M.; Lisetskiy, Alexander F.

2014-09-01

The results of an 18-nucleon No Core Shell Model calculation, performed in a large basis space using a bare, soft NN interaction, can be projected into the 0 ℏω space, i.e., the sd -shell. Because the 16 nucleons in the 16O core are frozen in the 0 ℏω space, all the correlations of the 18-nucleon system are captured by the two valence, sd -shell nucleons. By the projection, we obtain microscopically the sd -shell 2-body effective interactions, the core energy and the sd -shell s.p. energies. Thus, the input for standard shell-model calculations can be determined microscopically by this approach. If the same procedure is then applied to 19-nucleon systems, the sd -shell 3-body effective interactions can also be obtained, indicating the importance of these 3-body effective interactions relative to the 2-body effective interactions. Applications to A = 19 and heavier nuclei with different intrinsic NN interactions will be presented and discussed. The results of an 18-nucleon No Core Shell Model calculation, performed in a large basis space using a bare, soft NN interaction, can be projected into the 0 ℏω space, i.e., the sd -shell. Because the 16 nucleons in the 16O core are frozen in the 0 ℏω space, all the correlations of the 18-nucleon system are captured by the two valence, sd -shell nucleons. By the projection, we obtain microscopically the sd -shell 2-body effective interactions, the core energy and the sd -shell s.p. energies. Thus, the input for standard shell-model calculations can be determined microscopically by this approach. If the same procedure is then applied to 19-nucleon systems, the sd -shell 3-body effective interactions can also be obtained, indicating the importance of these 3-body effective interactions relative to the 2-body effective interactions. Applications to A = 19 and heavier nuclei with different intrinsic NN interactions will be presented and discussed. Supported by the US NSF under Grant No. 0854912, the US DOE under Grants Nos. DESC0008485 and DE-FG02-87ER40371, the Higher Education Council of Turkey(YOK), and the Ministry of Education and Science of Russian Fed. under contracts P521 and 14.v37.21.1297.

Differential mesocorticolimbic responses to palatable food in binge eating prone and binge eating resistant female rats.

PubMed

Sinclair, Elaine B; Culbert, Kristen M; Gradl, Dana R; Richardson, Kimberlei A; Klump, Kelly L; Sisk, Cheryl L

2015-12-01

Binge eating is a key symptom of many eating disorders (e.g. binge eating disorder, bulimia nervosa, anorexia nervosa binge/purge type), yet the neurobiological underpinnings of binge eating are poorly understood. The mesocorticolimbic reward circuit, including the nucleus accumbens and the medial prefrontal cortex, is likely involved because this circuit mediates the hedonic value and incentive salience of palatable foods (PF). Here we tested the hypothesis that higher propensity for binge eating is associated with a heightened response (i.e., Fos induction) of the nucleus accumbens and medial prefrontal cortex to PF, using an animal model that identifies binge eating prone (BEP) and binge eating resistant (BER) rats. Forty adult female Sprague-Dawley rats were given intermittent access to PF (high fat pellets) 3×/week for 3 weeks. Based on a pattern of either consistently high or consistently low PF consumption across these feeding tests, 8 rats met criteria for categorization as BEP, and 11 rats met criteria for categorization as BER. One week after the final feeding test, BEP and BER rats were either exposed to PF in their home cages or were given no PF in their home cages for 1h prior to perfusion, leading to three experimental groups for the Fos analysis: BEPs given PF, BERs given PF, and a No PF control group. The total number of Fos-immunoreactive (Fos-ir) cells in the nucleus accumbens core and shell, and the cingulate, prelimbic, and infralimbic regions of the medial prefrontal cortex was estimated by stereological analysis. PF induced higher Fos expression in the nucleus accumbens shell and core and in the prelimbic and infralimbic cortex of BEP rats compared to No PF controls. Throughout the nucleus accumbens and medial prefrontal cortex, PF induced higher Fos expression in BEP than in BER rats, even after adjusting for differences in PF intake. Differences in the neural activation pattern between BEP and BER rats were more robust in prefrontal cortex than in nucleus accumbens. These data confirm that PF activates brain regions responsible for encoding the incentive salience and hedonic properties of PF, and suggest that binge eating proneness is associated with enhanced responses to PF in brain regions that exert executive control over food reward. Copyright © 2015 Elsevier Inc. All rights reserved.

Differential mesocorticolimbic responses to palatable food in binge eating prone and binge eating resistant female rats

PubMed Central

Sinclair, Elaine B.; Culbert, Kristen M.; Gradl, Dana R.; Richardson, Kimberlei A.; Klump, Kelly L.; Sisk, Cheryl L.

2017-01-01

Binge eating is a key symptom of many eating disorders (e.g. binge eating disorder, bulimia nervosa, anorexia nervosa binge/purge type), yet the neurobiological underpinnings of binge eating are poorly understood. The mesocorticolimbic reward circuit, including the nucleus accumbens and the medial prefrontal cortex, is likely involved because this circuit mediates the hedonic value and incentive salience of palatable foods (PF). Here we tested the hypothesis that higher propensity for binge eating is associated with a heightened response (i.e., Fos induction) of the nucleus accumbens and medial prefrontal cortex to PF, using an animal model that identifies binge eating prone (BEP) and binge eating resistant (BER) rats. Forty adult female Sprague–Dawley rats were given intermittent access to PF (high fat pellets) 3×/week for 3 weeks. Based on a pattern of either consistently high or consistently low PF consumption across these feeding tests, 8 rats met criteria for categorization as BEP, and 11 rats met criteria for categorization as BER. One week after the final feeding test, BEP and BER rats were either exposed to PF in their home cages or were given no PF in their home cages for 1 h prior to perfusion, leading to three experimental groups for the Fos analysis: BEPs given PF, BERs given PF, and a No PF control group. The total number of Fos-immunoreactive (Fos-ir) cells in the nucleus accumbens core and shell, and the cingulate, prelimbic, and infralimbic regions of the medial prefrontal cortex was estimated by stereological analysis. PF induced higher Fos expression in the nucleus accumbens shell and core and in the prelimbic and infralimbic cortex of BEP rats compared to No PF controls. Throughout the nucleus accumbens and medial pre-frontal cortex, PF induced higher Fos expression in BEP than in BER rats, even after adjusting for differences in PF intake. Differences in the neural activation pattern between BEP and BER rats were more robust in prefrontal cortex than in nucleus accumbens. These data confirm that PF activates brain regions responsible for encoding the incentive salience and hedonic properties of PF, and suggest that binge eating proneness is associated with enhanced responses to PF in brain regions that exert executive control over food reward. PMID:26459117

Evaluation of the utility value of three diagnostic methods in the detection of malaria parasites in endemic area.

PubMed

Ugah, Uchenna Iyioku; Alo, Moses Nnaemeka; Owolabi, Jacob Oluwabusuyi; Okata-Nwali, Oluchi DivineGift; Ekejindu, Ifeoma Mercy; Ibeh, Nancy; Elom, Michael Okpara

2017-05-06

Malaria is a debilitating disease with high morbidity and mortality in Africa, commonly caused by different species of the genus Plasmodium in humans. Misdiagnosis is a major challenge in endemic areas because of other disease complications and technical expertise of the medical laboratory staff. Microscopic method using Giemsa-stained blood film has been the mainstay of diagnosis of malaria. However, since 1993 when rapid diagnostic test (RDT) kits were introduced, they have proved to be effective in the diagnosis of malaria. This study was aimed at comparing the accuracy of microscopy and RDTs in the diagnosis of malaria using nested PCR as the reference standard. Four hundred and twenty (420) venous blood specimens were collected from patients attending different General Hospitals in Ebonyi State with clinical symptoms of malaria. The samples were tested with Giemsa-stained microscopy and three RDTs. Fifty specimens were randomly selected for molecular analysis. Using different diagnostic methods, the prevalence of malaria among the subjects studied was 25.95% as detected by microscopy, prevalence found among the RDTs was 22.90, 15.20 and 54.80% for Carestart, SD Bioline PF and SD Bioline PF/PV, respectively. Molecular assay yielded a prevalence of 32%. The major specie identified was Plasmodium falciparum; there was co-infection of P. falciparum with Plasmodium malariae and Plasmodium ovale. The sensitivity and specificity of microscopy was 50.00 and 70.59% while that of the RDTs were (25.00 and 85.29%), (25.00 and 94.12%) and (68.75 and 52.94%) for Carestart, SD Bioline PF and SD Bioline PF/PV, respectively. Cohen's kappa coefficient was used to measure the level of agreement of the methods with nested PCR. Microscopy showed a moderate measure of agreement (k = 0.491), Carestart showed a good measure of agreement (k = 0.611), SD Bioline PF showed a fair measure of agreement (k = 0.226) while SD Bioline PF/PV showed a poor measure of agreement (k = 0.172). This study recommends that the policy of malaria diagnosis be changed such that the routine diagnosis of malaria is done by a combination of both microscopy and a RDT kit of high sensitivity and specificity so as to complement the errors associated with either of the methods. The finding of P. ovale in the study area necessitates an expanded molecular epidemiology of malaria within the study area.

A comparison of the solvation structure and dynamics of the lithium ion in linear organic carbonates with different alkyl chain lengths.

PubMed

Fulfer, K D; Kuroda, D G

2017-09-20

The structure and dynamics of electrolytes composed of lithium hexafluorophosphate (LiPF 6 ) in dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate were investigated using a combination of linear and two-dimensional infrared spectroscopies. The solutions studied here have a LiPF 6 concentration of X(LiPF 6 ) = 0.09, which is typically found in commercial lithium ion batteries. This study focuses on comparing the differences in the solvation shell structure and dynamics produced by linear organic carbonates of different alkyl chain lengths. The IR experiments show that either linear carbonate forms a tetrahedral solvation shell (coordination number of 4) around the lithium ion irrespective of whether the solvation shell has anions in close proximity to the carbonates. Moreover, analysis of the absorption cross sections via FTIR and DFT computations reveals a distortion in the angle formed by Li + -O[double bond, length as m-dash]C which decreases from the expected 180° when the alkyl chains of the carbonate are lengthened. In addition, our findings also reveal that, likely due to its asymmetric structure, ethyl methyl carbonate has a significantly more distorted tetrahedral lithium ion solvation shell than either of the other two investigated carbonates. IR photon echo studies further demonstrate that the motions of the solvation shell have a time scale of a few picoseconds for all three linear carbonates. Interestingly, a slowdown of the in place-motions of the first solvation shell is observed when the carbonate has a longer alkyl chain length irrespective of the symmetry. In addition, vibrational energy transfer with a time scale of tens of picoseconds is observed between strongly coupled modes arising from the solvation shell structure of the Li + which corroborates the modeling of these solvation shells in terms of highly coupled vibrational states. Results of this study provide new insights into the molecular structure and dynamics of the lithium ion electrolyte components as a function of solvent structure.

[Application of the Polish version of CHQ-PF28 questionnaire in two population studies carried out in 2003 and 2008].

PubMed

Małkowska-Szkutnik, Agnieszka; Tabak, Izabela; Mazur, Joanna

2010-01-01

To conduct a psychometric analysis of the Polish version of the CHQ-PF28 questionnaire for measuring the health-related quality of life (HRQL) of children and adolescents, on the basis of two population studies carried out in 2003 and 2008. The CHQ-PF28 questionnaire was completed by parents of 1093 adolescents surveyed in 2003 and by parents of 605 adolescents surveyed in 2008. The average age of children was similar (13.4 yrs). An exploratory and confirmatory factor analysis was carried out on a combined sample from those studies. The HRQL profile of adolescents displaying and not displaying health problems, was compared. Mean standardized quality of life scores were calculated for all 13 partial dimensions and a two summary dimensions of physical and psychosocial health where high CHQ score always means better quality of life. In the 2003 study, the mean scores of partial scales ranged between 59.78 (SD = 20.39) for the scale of family coherence and 97.07 (SD = 11.88) for the scale of emotional limitations in playing social roles. In the 2008 study, mean scores for the same subscales were as follows: 59.17 (SD = 19.50) and 96.17 (SD = 14,45). It was concluded that parents assessed children's psychosocial health as worse than their children's physical health. In girls, higher mean scores were noted in the scales of self-esteem and behavioural disorders; in boys, higher mean scores were recorded in the scale of pain sensation. The reliability of partial scales was measured using alpha-Cronbach, which only for four scales was above 0.7. Six items were identified, which severely impair psychometric characteristics of the Polish version of the CHQ-PF28. A clear link was found between mean CHQ-PF28 indeces and the results of screening tests which identify physical and mental health abnormalities, such as the SDQ (Strengths and Difficulties Questionnaire), as well as the CSHCN (Children with Special Health Care Needs) test. The Polish version of the CHQ-PF28 questionnaire has satisfactory psychometric characteristics. A wider use of the CHQ-PF28 in clinical research and population studies in Poland is fully justified. However, we would suggest implementing its abbreviated version, excluding items, which may affect the reliability and validity of the subscales and of the overall research tool.

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

Richter, W. A.; Brown, B. Alex

Assignments are made between theory and experiment of corresponding levels in {sup 26}Mg levels based on energies, lifetimes, branching ratios, electron scattering form factors, and reduced electromagnetic transition strengths. Results based on the new sd-shell interactions USDA (universal sd-shell interaction A) and USDB (universal sd-shell interaction B), as well as the older USD interaction, are compared.

Nuclear structure for SNe r- and neutrino processes

NASA Astrophysics Data System (ADS)

Suzuki, Toshio

2014-09-01

SNe r- and neutrino-processes are investigated based on recent advances in the studies of spin responses in nuclei. New shell-model Hamiltonians, which can well describe spin responses in nuclei with proper tensor components, are used to make accurate evaluations of reaction cross sections and rates in astrophysical processes. Nucleosyntheses in SNe r- and ν -processes as well as rp-processes are discussed with these new reaction rates with improved accuracies. (1) Beta-decay rates for N = 126 isotones are evaluated by shell-model calculations, and new rates are applied to study r-process nucleosynthesis in SNe's around its third peak as well as beyond the peak region up to uranium. (2) ν -processes for light-element synthesis in core-collapse SNe are studied with a new shell-model Hamiltonian in p-shell, SFO. Effects of MSW ν -oscillations on the production yields of 7Li and 11B and sensitivity of the yield ratio on ν -oscillation parameters are discussed. ν -induced reactions on 16O are also studied. (3) A new shell-model Hamiltonian in pf-shell, GXPF1J, is used to evaluate e-capture rates in pf-shell nuclei at stellar environments. New e-capture rates are applied to study nucleosynthesis in type-Ia supernova explosions, rp-process and X-ray bursts.

Performance of SD Bioline Malaria Ag Pf/Pan rapid test in the diagnosis of malaria in South-Kivu, DR Congo.

PubMed

Kashosi, Théophile Mitima; Mutuga, Joseph Minani; Byadunia, Devotte Sifa; Mutendela, John Kivukuto; Mulenda, Basimike; Mubagwa, Kanigula

2017-01-01

Use of malaria rapid diagnostic tests (RDTs) has improved the management of this disease. We evaluated the validity of the SD-Bioline Malaria-Ag-Pf/Pan™ (Batch 60952) RDT supplied by the Malaria Control Program of the DRCongo. cChildren (n = 460) aged below 5 years seen in curative care (CC) for suspected malaria and in pre-school consultation (PSC) in two rural centers underwent clinical evaluation and capillary blood collection for microscopic reading of thick smear (TS) and thin film (BF), and for RDT. Sensitivity (Se), specificity (Sp), positive (PPV) and negative (NPV) predictive values of the RDT, and the corresponding accuracy and Youden indices were determined using microscopic data as reference. Results were compared using the Chi-square test. Microscopy showed malaria infection in 53.8% of CC and in 10.8% of PSC children. Similar results were obtained using the RDT (CC: 47.1%; PSC: 18.3%; P > 0.05 vs. microscopy). Se of the RDT was 82.1%, Sp 92.0%, PPV 88.5% and NPV 87.4%. RDT positivity was significantly (p < 0.01) associated with some symptoms (chills, profuse sweating) and with a recent history of malaria attack. In addition, Se of the RDT depended on parasitemia and decreased at low parasite denstity. SD-Bioline Malaria-Ag-Pf/Pan™ RDT has a relatively good sensitivity and specificity but seems useful only for high parasitemia. Negative SD Bioline Malaria Ag Pf/Pan™ RDT should be complemented with microscopy when clinical signs suggest malaria.

Symmetry energies for A =24 and 48 and the USD and KB3 shell model Hamiltonians

NASA Astrophysics Data System (ADS)

Kingan, A.; Neergârd, K.; Zamick, L.

2017-12-01

Calculations in the sd and pf shells reported some time ago by Satuła et al. [Phys. Lett. B 407, 103 (1997), 10.1016/S0370-2693(97)00711-9] are redone for an extended analysis of the results. As in the original work, we do calculations for one mass number in each shell and consider in each case the sequence of lowest energies for isospins 0, 2, and 4, briefly the symmetry spectrum. Following further the original work, we study how this spectrum changes when parts of the two-nucleon interaction are turned off. The variation of its width is explored in detail. A differential combination ɛW of the three energies was taken in the original work as a measure of the so-called Wigner term in semiempirical mass formulas, and it was found to decrease drastically when the two-nucleon interaction in the channel of zero isospin is turned off. Our analysis shows that the width of the symmetry spectrum experiences an equally drastic decrease, which can be explained qualitatively in terms of schematic approximations. We therefore suggest that the decrease of ɛW be seen mainly as a side effect of a narrowing of the symmetry spectrum rather than an independent manifestation of the two-nucleon interaction in the channel of zero isospin.

Microscopic Shell Model Calculations for sd-Shell Nuclei

NASA Astrophysics Data System (ADS)

Barrett, Bruce R.; Dikmen, Erdal; Maris, Pieter; Shirokov, Andrey M.; Smirnova, Nadya A.; Vary, James P.

Several techniques now exist for performing detailed and accurate calculations of the structure of light nuclei, i.e., A ≤ 16. Going to heavier nuclei requires new techniques or extensions of old ones. One of these is the so-called No Core Shell Model (NCSM) with a Core approach, which involves an Okubo-Lee-Suzuki (OLS) transformation of a converged NCSM result into a single major shell, such as the sd-shell. The obtained effective two-body matrix elements can be separated into core and single-particle (s.p.) energies plus residual two-body interactions, which can be used for performing standard shell-model (SSM) calculations. As an example, an application of this procedure will be given for nuclei at the beginning ofthe sd-shell.

Motor Imagery Practice for Enhancing Elevé Performance Among Professional Dancers: A Pilot Study.

PubMed

Abraham, Amit; Dunsky, Ayelet; Dickstein, Ruth

2016-09-01

Elevé is a core dance movement requiring the greatest ankle plantarflexion (PF) range of motion (ROM). One possible way to enhance elevé performance is by using motor imagery practice (MIP). The aims of this pilot study were to investigate: 1) functional ankle PF maximal angles and ROM while performing elevé among professional dancers, 2) the effect of MIP on enhancing elevé performance, and 3) participants' views on the MIP intervention and its feasibility in a professional dance company setting. Five professional dancers, mean age 31 yrs (SD 1.87), participated in a 2-week MIP intervention. Data on ankle PF maximal angles and ROM were collected pre- and post-intervention using 3-dimensional motion capture while performing repeat (10 repetitions) and static (10 sec) elevé. At baseline, ankle PF maximal angles were 169.20° (SD 2.81°) and 168.36° (2.23°) and ankle PF ROM were 40.21° (3.35°) and 35.94° (3.95°) for the repeat and static tasks, respectively. After the MIP intervention, ankle PF maximal angles were 170.28° (4.26°) and 170.74° (3.77°) and ankle PF ROM were 41.53° (2.33°) and 39.30° (2.30°) for the repeat and static tasks, respectively. Feasibility of MIP was established with 100% compliance and positive views were expressed by participants. The results suggest MIP holds potential as an adjunct training method for enhancing elevé performance among professional dancers.

Empirical parameters for solvent acidity, basicity, dipolarity, and polarizability of the ionic liquids [BMIM][BF4] and [BMIM][PF6].

PubMed

del Valle, J C; García Blanco, F; Catalán, J

2015-04-02

The empirical solvent scales for polarizability (SP), dipolarity (SdP), acidity (SA), and basicity (SB) have been successfully used to interpret the solvatochromism of compounds dissolved in organic solvents and their solvent mixtures. Providing that the published solvatochromic parameters for the ionic liquids 1-(1-butyl)-3-methylimidazolium tetrafluoroborate, [BMIM][BF4] and 1-(1-butyl)-3-methylimidazolium hexafluorophosphate, [BMIM][PF6], are excessively widespread, their SP, SdP, SA, and SB values are measured herein at temperatures from 293 to 353 K. Four key points are emphasized herein: (i) the origin of the solvatochromic solvent scales--the gas phase, that is the absence of any medium perturbation--; (ii) the separation of the polarizability and dipolarity effects; (iii) the simplification of the probing process in order to obtain the solvatochromic parameters; and (iv) the SP, SdP, SA, and SB solvent scales can probe the polarizability, dipolarity, acidity, and basicity of ionic liquids as well as of organic solvents and water-organic solvent mixtures. From the multiparameter approach using the four pure solvent scales one can draw the conclusion that (a) the solvent influence of [BMIM][BF4] parallels that of formamide at 293 K, both of them miscible with water; (b) [BMIM][PF6] shows a set of solvatochromic parameters similar to that of chloroacetonitrile, both of them water insoluble; and (c) that the corresponding solvent acidity and basicity of the ionic liquids can be explained to a great extent from the cation species by comparing the empirical parameters of [BMIM](+) with those of the solvent 1-methylimidazole. The insolubility of [BMIM][PF6] in water as compared to [BMIM][BF4] is tentatively connected to some extent to the larger molar volume of the anion [PF6](-), and to the difference in basicity of [PF6](-) and [BF4](-).

Functional characterization and molecular mechanism exploration of three granulin epithelin precursor splice variants in biomineralization of the pearl oyster Pinctada fucata.

PubMed

Zhao, Mi; He, Maoxian; Huang, Xiande; Wang, Qi; Shi, Yu

2016-02-01

The granulin/epithelin precursor (GEP) encodes a glycoprotein precursor which exhibits pleiotropic tissue growth factor activity with multiple functions. Here, GEP was isolated and its role in the shell biomineralization process of the pearl oyster Pinctada fucata was investigated. Three forms of GEP mRNA were isolated from the pearl oyster (designated PfGEP-1, PfGEP-2 and PfGEP-3). Genomic DNA flanking the splicing region of the PfGEP variants was sequenced and it was found that PfGEP-2 splices out Exon 4, whereas PfGEP-3 splices out Exon 3 compared to PfGEP-1. PfGEP-1 (1505 amino acids) consists of 18 granulin domains, whereas PfGEP-2 (1459 amino acids) and PfGEP-3 (1471 amino acids) consist of 17.5 granulin domains, respectively. Analyses of PfGEP-1 and PfGEP-3 mRNA showed differential patterns in the tissues and developmental stages. Western blotting results showed that the three splice variants can translate to proteins in HEK293T cells. A knockdown experiment using PfGEP dsRNA showed decreased PfGEP-1/PfGEP-3 and PfMSX mRNA, and irregular crystallization of the nacreous layer using scanning electron microscopy. In luciferase assays, co-transfection of PfGEP-1 could activate as well as repress luciferase expression of the reporter plasmid driven by the PfMSX promoter, whereas PfGEP-3 stimulated the expression, elucidating the molecular mechanisms involved in the correlation between PfGEP and PfMSX. These results suggested that GEP variants might function differently during the biomineralization process, which provides new knowledge on the mechanism regulating nacre formation.

Pteropods in Southern Ocean ecosystems

NASA Astrophysics Data System (ADS)

Hunt, B. P. V.; Pakhomov, E. A.; Hosie, G. W.; Siegel, V.; Ward, P.; Bernard, K.

2008-09-01

To date, little research has been carried out on pelagic gastropod molluscs (pteropods) in Southern Ocean ecosystems. However, recent predictions are that, due to acidification resulting from a business as usual approach to CO 2 emissions (IS92a), Southern Ocean surface waters may begin to become uninhabitable for aragonite shelled thecosome pteropods by 2050. To gain insight into the potential impact that this would have on Southern Ocean ecosystems, we have here synthesized available data on pteropod distributions and densities, assessed current knowledge of pteropod ecology, and highlighted knowledge gaps and directions for future research on this zooplankton group. Six species of pteropod are typical of the Southern Ocean south of the Sub-Tropical Convergence, including the four Thecosomes Limacina helicina antarctica, Limacina retroversa australis, Clio pyramidata, and Clio piatkowskii, and two Gymnosomes Clione limacina antarctica and Spongiobranchaea australis. Limacina retroversa australis dominated pteropod densities north of the Polar Front (PF), averaging 60 ind m -3 (max = 800 ind m -3) and 11% of total zooplankton at the Prince Edward Islands. South of the PF L. helicina antarctica predominated, averaging 165 ind m -3 (max = 2681 ind m -3) and up to >35% of total zooplankton at South Georgia, and up to 1397 ind m -3 and 63% of total zooplankton in the Ross Sea. Combined pteropods contributed <5% to total zooplankton in the Lazarev Sea, but 15% (max = 93%) to macrozooplankton in the East Antarctic. In addition to regional density distributions we have synthesized data on vertical distributions, seasonal cycles, and inter-annual density variation. Trophically, gymnosome are specialist predators on thecosomes, while thecosomes are considered predominantly herbivorous, capturing food with a mucous web. The ingestion rates of L. retroversa australis are in the upper range for sub-Antarctic mesozooplankton (31.2-4196.9 ng pig ind -1 d -1), while those of L. helicina antarctica and C. pyramidata are in the upper range for all Southern Ocean zooplankton, in the latter species reaching 27,757 ng pig ind -1 d -1 and >40% of community grazing impact. Further research is required to quantify diet selectivity, the effect of phytoplankton composition on growth and reproductive success, and the role of carnivory in thecosomes. Life histories are a significant knowledge gap for Southern Ocean pteropods, a single study having been completed for L. retroversa australis, making population studies a priority for this group. Pteropods appear to be important in biogeochemical cycling, thecosome shells contributing >50% to carbonate flux in the deep ocean south of the PF. Pteropods may also contribute significantly to organic carbon flux through the production of fast sinking faecal pellets and mucous flocs, and rapid sinking of dead animals ballasted by their aragonite shells. Quantification of these contributions requires data on mucous web production rates, egestion rates, assimilation efficiencies, metabolic rates, and faecal pellet morphology for application to sediment trap studies. Based on the available data, pteropods are regionally significant components of the Southern Ocean pelagic ecosystem. However, there is an urgent need for focused research on this group in order to quantify how a decline in pteropod densities may impact on Southern Ocean ecosystems.

Magnetic solid phase extraction using ionic liquid-coated core-shell magnetic nanoparticles followed by high-performance liquid chromatography for determination of Rhodamine B in food samples.

PubMed

Chen, Jieping; Zhu, Xiashi

2016-06-01

Three hydrophobic ionic liquids (ILs) (1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluoro-phosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluorophosphate ([OMIM]PF6)) were used to coat Fe3O4@SiO2 nanoparticles (NPs) with core-shell structures to prepare magnetic solid phase extraction (MSPE) agents (Fe3O4@SiO2@IL). A novel method of MSPE coupled with high-performance liquid chromatography for the separation/analysis of Rhodamine B was then established. The results showed that Rhodamine B was adsorbed rapidly on Fe3O4@SiO2@[OMIM]PF6 and was released using ethanol. Under optimal conditions, the pre-concentration factor for the proposed method was 25. The linear range, limit of detection (LOD), correlation coefficient (R), and relative standard deviation (RSD) were found to be 0.50-150.00 μgL(-1), 0.08 μgL(-1), 0.9999, and 0.51% (n=3, c=10.00 μgL(-1)), respectively. The Fe3O4@SiO2 NPs could be re-used up to 10 times. The method was successfully applied to the determination of Rhodamine B in food samples. Copyright © 2016. Published by Elsevier Ltd.

Benzoate-Induced High-Nuclearity Silver Thiolate Clusters.

PubMed

Su, Yan-Min; Liu, Wei; Wang, Zhi; Wang, Shu-Ao; Li, Yan-An; Yu, Fei; Zhao, Quan-Qin; Wang, Xing-Po; Tung, Chen-Ho; Sun, Di

2018-04-03

Compared with the well-known anion-templated effects in shaping silver thiolate clusters, the influence from the organic ligands in the outer shell is still poorly understood. Herein, three new benzoate-functionalized high-nuclearity silver(I) thiolate clusters are isolated and characterized for the first time in the presence of diverse anion templates such as S 2- , α-[Mo 5 O 18 ] 6- , and MoO 4 2- . Single-crystal X-ray analysis reveals that the nuclearities of the three silver clusters (SD/Ag28, SD/Ag29, SD/Ag30) vary from 32 to 38 to 78 with co-capped tBuS - and benzoate ligands on the surface. SD/Ag28 is a turtle-like cluster comprising a Ag 29 shell caging a Ag 3 S 3 trigon in the center, whereas SD/Ag29 is a prolate Ag 38 sphere templated by the α-[Mo 5 O 18 ] 6- anion. Upon changing from benzoate to methoxyl-substituted benzoate, SD/Ag30 is isolated as a very complicated core-shell spherical cluster composed of a Ag 57 shell and a vase-like Ag 21 S 13 core. Four MoO 4 2- anions are arranged in a supertetrahedron and located in the interstice between the core and shell. Introduction of the bulky benzoate changes elaborately the nuclearity and arrangements of silver polygons on the shell of silver clusters, which is exemplified by comparing SD/Ag28 and a known similar silver thiolate cluster. The three new clusters emit luminescence in the near-infrared (NIR) region and show different thermochromic luminescence properties. This work presents a flexible approach to synthetic studies of high-nuclearity silver clusters decorated by different benzoates, and structural modulations are also achieved. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

PfSMAD4 plays a role in biomineralization and can transduce bone morphogenetic protein-2 signals in the pearl oyster Pinctada fucata.

PubMed

Zhao, Mi; Shi, Yu; He, Maoxian; Huang, Xiande; Wang, Qi

2016-04-26

Mollusca is the second largest phylum in nature. The shell of molluscs is a remarkable example of a natural composite biomaterial. Biomineralization and how it affects mollusks is a popular research topic. The BMP-2 signaling pathway plays a canonical role in biomineralization. SMAD4 is an intracellular transmitter in the BMP signaling pathway in mammals, and some genomic data show SMAD4's involvement in BMP signaling in invertebrates, but whether SMAD4 plays a conservative role in pearl oyster, Pinctada fucata, still need to be tested. In this study, we identified a SMAD4 gene (hereafter designated PfSMAD4) in pearl oyster Pinctada fucata. Bioinformatics analysis of PfSMAD4 showed high identity with its orthologs. PfSMAD4 was located in the cytoplasm in immunofluorescence assays and analyses of PfSMAD4 mRNA in tissues and developmental stages showed high expression in ovaries and D-shaped larvae. An RNA interference experiment, performed by PfSMAD4 double-stranded RNA (dsRNA) injection, demonstrated inhibition not only of nacre growth but also organic sheet formation with a decrease in PfSMAD4 expression. A knockdown experiment using PfBMP2 dsRNA showed decreased PfBMP2 and PfSMAD4 mRNA and irregular crystallization of the nacreous layer using scanning electron microscopy. In co-transfection experiments, PfBMP2-transactivated reporter constructs contained PfSMAD4 promoter sequences. Our results suggest that PfSMAD4 plays a role in biomineralization and can transduce BMP signals in P. fucata. Our data provides important clues about the molecular mechanisms that regulate biomineralization in pearl oyster.

Central depression in nuclear density and its consequences for the shell structure of superheavy nuclei

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

Afanasjev, A.V.; Laboratory of Radiation Physics, Institute of Solid State Physics, University of Latvia, LV 2169 Salaspils, Miera str. 31; Frauendorf, S.

The influence of the central depression in the density distribution of spherical superheavy nuclei on the shell structure is studied within the relativistic mean-field theory. A large depression leads to the shell gaps at the proton Z=120 and neutron N=172 numbers, whereas a flatter density distribution favors N=184 and leads to the appearance of a Z=126 shell gap and to the decrease of the size of the Z=120 shell gap. The correlations between the magic shell gaps and the magnitude of the central depression are discussed for relativistic and nonrelativistic mean field theories.

Plantar fascia anatomy and its relationship with Achilles tendon and paratenon

PubMed Central

Stecco, Carla; Corradin, Marco; Macchi, Veronica; Morra, Aldo; Porzionato, Andrea; Biz, Carlo; De Caro, Raffaele

2013-01-01

Although the plantar fascia (PF) has been studied quite well from a biomechanical viewpoint, its microscopic properties have been overlooked: nothing is known about its content of elastic fibers, the features of the extracellular matrix or the extent of innervation. From a functional and clinical standpoint, the PF is often correlated with the triceps surae muscle, but the anatomical grounds for this link are not clear. The aim of this work was to focus on the PF macroscopic and microscopic properties and study how Achilles tendon diseases might affect it. Twelve feet from unembalmed human cadavers were dissected to isolate the PF. Specimens from each PF were tested with various histological and immunohistochemical stains. In a second stage, 52 magnetic resonance images (MRI) obtained from patients complaining of aspecific ankle or foot pain were analyzed, dividing the cases into two groups based on the presence or absence of signs of degeneration and/or inflammation of the Achilles tendon. The thickness of PF and paratenon was assessed in the two groups and statistical analyses were conducted. The PF is a tissue firmly joined to plantar muscles and skin. Analyzing its possible connections to the sural structures showed that this fascia is more closely connected to the paratenon of Achilles tendon than to the Achilles tendon, through the periosteum of the heel. The PF extended medially and laterally, continuing into the deep fasciae enveloping the abductor hallucis and abductor digiti minimi muscles, respectively. The PF was rich in hyaluronan, probably produced by fibroblastic-like cells described as ‘fasciacytes’. Nerve endings and Pacini and Ruffini corpuscles were present, particularly in the medial and lateral portions, and on the surface of the muscles, suggesting a role for the PF in the proprioception of foot. In the radiological study, 27 of the 52 MRI showed signs of Achilles tendon inflammation and/or degeneration, and the PF was 3.43 ± 0.48 mm thick (99%CI and SD = 0.95), as opposed to 2.09 ± 0.24 mm (99%CI, SD = 0.47) in the patients in which the MRI revealed no Achilles tendon diseases; this difference in thickness of 1.29 ± 0.57 mm (99%CI) was statistically significant (P < 0.001). In the group of 27/52 patients with tendinopathies, the PF was more than 4.5 mm thick in 5, i.e. they exceeded the threshold for a diagnosis of plantar fasciitis. None of the other 25/52 paitents had a PF more than 4 mm thick. There was a statistically significant correlation between the thicknesses of the PF and the paratenon. These findings suggest that the plantar fascia has a role not only in supporting the longitudinal arch of the foot, but also in its proprioception and peripheral motor coordination. Its relationship with the paratenon of the Achilles tendon is consistent with the idea of triceps surae structures being involved in the PF pathology, so their rehabilitation can be considered appropriate. Finally, the high concentration of hyaluronan in the PF points to the feasibility of using hyaluronan injections in the fascia to treat plantar fasciitis. PMID:24028383

Paeoniflorin, a Monoterpene Glycoside, Protects the Brain from Cerebral Ischemic Injury via Inhibition of Apoptosis.

PubMed

Zhang, Yuqin; Li, Huang; Huang, Mingqing; Huang, Mei; Chu, Kedan; Xu, Wei; Zhang, Shengnan; Que, Jinhua; Chen, Lidian

2015-01-01

Paeoniflorin (PF) is a principal bioactive component, which exhibits many pharmacological effects, including protection against ischemic injury. This paper aimed to investigate the protective effect of PF both in vivo and in vitro. Middle cerebral artery occlusion (MCAO) was performed on male Sprague-Dawley (SD) rat for 2 h, and different doses of PF or vehicle were administered 2 h after reperfusion. Rats were sacrificed after 7 days treatment of PF/vehicle. PF treatment for 7 days ameliorated MCAO-induced neurological deficit and decreased the infarct area. Further study demonstrated that PF inhibited the over-activation of astrocytes and apoptosis of neurons, and PF promoted up-regulation of neuronal specific marker neuron-specific nuclear (NeuN) and microtubule-associated protein 2 (MAP-2) in brain. Moreover, NMDA-induced neuron apoptosis was employed. The in vitro study revealed that PF treatment protected against NMDA-induced cell apoptosis and neuronal loss via up-regulation of neuronal specific marker NeuN, MAP-2 and Bcl-2 and the down-regulation Bax. Taken together, the present study demonstrates that PF produces its protective effect by inhibiting the over-activation of astrocytes, apoptosis of neurons and up-regulation of neuronal specific marker NeuN, MAP-2, and B-cell lymphoma-2 (Bcl-2), and down-regulation Bax. Our study reveals that PF may be a potential neuroprotective agent for stroke and can provide basic data for clinical use.

Neutrino Spectra from Nuclear Weak Interactions in sd-Shell Nuclei under Astrophysical Conditions

NASA Astrophysics Data System (ADS)

Misch, G. Wendell; Sun, Yang; Fuller, George M.

2018-01-01

We present shell model calculations of nuclear neutrino energy spectra for 70 sd-shell nuclei over the mass number range A = 21–35. Our calculations include nuclear excited states as appropriate for the hot and dense conditions characteristic of pre-collapse massive stars. We consider neutrinos produced by charged lepton captures and decays, and for the first time in tabular form, neutral current nuclear deexcitation, providing neutrino energy spectra on the Fuller–Fowler–Newman temperature–density grid for these interaction channels for each nucleus. We use the full sd-shell model space to compute initial nuclear states up to 20 MeV excitation with transitions to final states up to 35–40 MeV, employing a modification of the Brink-Axel hypothesis to handle high-temperature population factors and the nuclear partition functions.

Symmetry of Isoscalar Matrix Elements and Systematics in the sd and beginning of fp shells

NASA Astrophysics Data System (ADS)

Orce, J. N.; Petkov, P.; Velázquez, V.; McKay, C. J.; Lesher, S. R.; Choudry, S.; Mynk, M.; Linnemann, A.; Jolie, J.; von Brentano, P.; Werner, V.; Yates, S. W.; McEllistrem, M. T.

2006-03-01

A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2T=1+ state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2T=1+ state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 21 (T=1)+ → 01 (T=1)+ transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A = 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.

The impact of a specific aqua-training for adult haemophilic patients--results of the WATERCISE study (WAT-QoL).

PubMed

Von Mackensen, S; Eifrig, B; Zäch, D; Kalnins, J; Wieloch, A; Zeller, W

2012-09-01

Sport is increasingly recommended for haemophilic patients due to physical and psychological benefits. 'WATERCISE' is a specific aqua-training programme for haemophiliacs in which endurance, strength, coordination and mobility are trained. In the WAT-QoL study benefits and risks of regular WATERCISE training sessions were investigated in terms of health-related quality of life (HRQoL), physical functioning (PF), orthopaedic joint status (OJS), bleeding frequency and factor consumption. Patients in the WATERCISE group attended an aqua-training programme once a week for 1 h over 12 months, patients in the control group did not. Patients were matched for clinical and demographic data. Information on clinical data, orthopaedic status, PF (HEP-Test-Q) and HRQoL were collected in both groups at baseline and at follow-up (6 and 12 months). Twenty-eight adult severely affected haemophilic patients (WATERCISE group: 10 haemophilia A (HA), 3 haemophilia B (HB) patients; control group: 12 HA and 3 HB patients) were enrolled (aged 40.68 ± 12.7 years). Baseline data (body mass indices, OJS, sportive activities, HRQoL and PF) were well distributed between groups. After 12 months the WATERCISE group reported a significantly better PF (M(W) = 65.22, SD = 11.3; M(C) = 52.5, SD = 15.0), especially for endurance (P < 0.004). Although always differently reported by the patients within the WATERCISE group, HRQoL did not prove to be significantly different between groups. WATERCISE seems to have a positive effect on the PF of patients suffering from haemophilia. These study findings need to be further investigated in a larger study group. © 2012 Blackwell Publishing Ltd.

The problem of deriving the field-induced thermal emission in Poole-Frenkel theories

NASA Astrophysics Data System (ADS)

Ongaro, R.; Pillonnet, A.

1992-10-01

A discussion is made of the legitimity of implementing the usual model of field-assisted release of electrons, over the lowered potential barrier of donors. It is stressed that no reliable interpretation can avail for the usual modelling of wells, on which Poole-Frenkel (PF) derivations are established. This is so because there does not seem to exist reliable ways of implanting a Coulomb potential well in the gap of a material. In an attempt to bridge the gap between the classical potential-energy approaches and the total-energy approach of Mahapatra and Roy, a Bohr-type model of wells is proposed. In addition, a brief review of quantum treatments of electronic transport in materials is presented, in order to see if more reliable ways of approaching PF effect can be derived on undisputable bases. Finally, it is concluded that, presently, PF effect can be established safely neither theoretically nor experimentally.

Influence of carbon nanotubes on the optical properties of plasticized solid polymer electrolytes

NASA Astrophysics Data System (ADS)

Ibrahim, Suriani; Yasin, Siti Mariah Mohd; Johan, Mohd Rafie

2013-07-01

Polyethylene oxide (PEO) based solid polymer electrolyte films complexed with lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC) and carbon nanotubes (CNTs) are prepared by solution-casting technique. The complexation of doping materials with polymer is confirmed by X-ray diffraction and infrared studies. The incorporation of LiPF6, EC and CNTs into the host polymer shows a significant increase in conductivity of 10-10 and 10-3 S cm-1. The optical properties such as direct and indirect band gaps are investigated for pure and doped polymer films within a wavelength range of 200-400 nm. It is found that the energy gaps and band edge values shift towards lower energies upon doping. It is shown that LiPF6, EC and CNTs are responsible for the formation of defects in polymer electrolytes, which increases the degree of disorder in the films.

Spherical silicon-shell photonic band gap structures fabricated by laser-assisted chemical vapor deposition

NASA Astrophysics Data System (ADS)

Wang, H.; Yang, Z. Y.; Lu, Y. F.

2007-02-01

Laser-assisted chemical vapor deposition was applied in fabricating three-dimensional (3D) spherical-shell photonic band gap (PBG) structures by depositing silicon shells covering silica particles, which had been self-assembled into 3D colloidal crystals. The colloidal crystals of self-assembled silica particles were formed on silicon substrates using the isothermal heating evaporation approach. A continuous wave Nd:YAG laser (1064nm wavelength) was used to deposit silicon shells by thermally decomposing disilane gas. Periodic silicon-shell/silica-particle PBG structures were obtained. By removing the silica particles enclosed in the silicon shells using hydrofluoric acid, hollow spherical silicon-shell arrays were produced. This technique is capable of fabricating structures with complete photonic band gaps, which is predicted by simulations with the plane wave method. The techniques developed in this study have the potential to flexibly engineer the positions of the PBGs by varying both the silica particle size and the silicon-shell thickness. Ellipsometry was used to investigate the specific photonic band gaps for both structures.

Competitive lithium solvation of linear and cyclic carbonates from quantum chemistry

DOE PAGES

Kent, Paul R. C.; Ganesh, Panchapakesan; Borodin, Oleg; ...

2015-11-17

The composition of the lithium cation (Li+) solvation shell in mixed linear and cyclic carbonate-based electrolytes has been re-examined using Born–Oppenheimer molecular dynamics (BOMD) as a function of salt concentration and cluster calculations with ethylene carbonate:dimethyl carbonate (EC:DMC)–LiPF 6 as a model system. A coordination preference for EC over DMC to a Li+ was found at low salt concentrations, while a slightly higher preference for DMC over EC was found at high salt concentrations. Analysis of the relative binding energies of the (EC) n(DMC) m–Li+ and (EC) n(DMC) m–LiPF 6 solvates in the gas-phase and for an implicit solvent (asmore » a function of the solvent dielectric constant) indicated that the DMC-containing Li+ solvates were stabilized relative to (EC 4)–Li+ and (EC) 3–LiPF 6 by immersing them in the implicit solvent. Such stabilization was more pronounced in the implicit solvents with a high dielectric constant. Results from previous Raman and IR experiments were reanalyzed and reconciled by correcting them for changes of the Raman activities, IR intensities and band shifts for the solvents which occur upon Li+ coordination. After these correction factors were applied to the results of BOMD simulations, the composition of the Li+ solvation shell from the BOMD simulations was found to agree well with the solvation numbers extracted from Raman experiments. Finally, the mechanism of the Li+ diffusion in the dilute (EC:DMC)LiPF 6 mixed solvent electrolyte was studied using the BOMD simulations.« less

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

Richter, W. A.; Mkhize, S.; Brown, B. Alex

The new Hamiltonians USDA and USDB for the sd shell are used to calculate M1 and E2 moments and transition matrix elements, Gamow-Teller {beta}-decay matrix elements, and spectroscopic factors for sd-shell nuclei from A=17 to A=39. The results are compared with those obtained with the older USD Hamiltonian and with experiment to explore the interaction sensitivity of these observables.

Resource Letter NSM-1: New insights into the nuclear shell model

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

Dean, David Jarvis; Hamilton, J. H.

2011-01-01

This Resource Letter provides a guide to the literature on the spherical shell model as applied to nuclei. The nuclear shell model describes the structure of nuclei starting with a nuclear core developed by the classical neutron and proton magic numbers N,Z=2,8,20,28,50,82, 126, where gaps occur in the single-particle energies as a shell is filled, and the interactions of valence nucleons that reside beyond that core. Various modern extensions of this model for spherical nuclei are likewise described. Significant extensions of the nuclear shell model include new magic numbers for spherical nuclei and now for deformed nuclei as well. Whenmore » both protons and neutrons have shell gaps at the same spherical or deformed shapes, they can reinforce each other to give added stability to that shape and lead to new magic numbers. The vanishings of the classical spherical shell model energy gaps and magic numbers in new neutron-rich nuclei are described. Spherical and deformed shell gaps are seen to be critical for the existence of elements with Z > 100.« less

Osmotic forces and gap junctions in spreading depression: a computational model

NASA Technical Reports Server (NTRS)

Shapiro, B. E.

2001-01-01

In a computational model of spreading depression (SD), ionic movement through a neuronal syncytium of cells connected by gap junctions is described electrodiffusively. Simulations predict that SD will not occur unless cells are allowed to expand in response to osmotic pressure gradients and K+ is allowed to move through gap junctions. SD waves of [K+]out approximately 25 to approximately 60 mM moving at approximately 2 to approximately 18 mm/min are predicted over the range of parametric values reported in gray matter, with extracellular space decreasing up to approximately 50%. Predicted waveform shape is qualitatively similar to laboratory reports. The delayed-rectifier, NMDA, BK, and Na+ currents are predicted to facilitate SD, while SK and A-type K+ currents and glial activity impede SD. These predictions are consonant with recent findings that gap junction poisons block SD and support the theories that cytosolic diffusion via gap junctions and osmotic forces are important mechanisms underlying SD.

A two-pronged structural analysis of retroviral maturation indicates that core formation proceeds by a disassembly-reassembly pathway rather than a displacive transition.

PubMed

Keller, Paul W; Huang, Rick K; England, Matthew R; Waki, Kayoko; Cheng, Naiqian; Heymann, J Bernard; Craven, Rebecca C; Freed, Eric O; Steven, Alasdair C

2013-12-01

Retrovirus maturation involves sequential cleavages of the Gag polyprotein, initially arrayed in a spherical shell, leading to formation of capsids with polyhedral or conical morphology. Evidence suggests that capsids assemble de novo inside maturing virions from dissociated capsid (CA) protein, but the possibility persists of a displacive pathway in which the CA shell remains assembled but is remodeled. Inhibition of the final cleavage between CA and spacer peptide SP1/SP blocks the production of mature capsids. We investigated whether retention of SP might render CA assembly incompetent by testing the ability of Rous sarcoma virus (RSV) CA-SP to assemble in vitro into icosahedral capsids. Capsids were indeed assembled and were indistinguishable from those formed by CA alone, indicating that SP was disordered. We also used cryo-electron tomography to characterize HIV-1 particles produced in the presence of maturation inhibitor PF-46396 or with the cleavage-blocking CA5 mutation. Inhibitor-treated virions have a shell that resembles the CA layer of the immature Gag shell but is less complete. Some CA protein is generated but usually not enough for a mature core to assemble. We propose that inhibitors like PF-46396 bind to the Gag lattice where they deny the protease access to the CA-SP1 cleavage site and prevent the release of CA. CA5 particles, which exhibit no cleavage at the CA-SP1 site, have spheroidal shells with relatively thin walls. It appears that this lattice progresses displacively toward a mature-like state but produces neither conical cores nor infectious virions. These observations support the disassembly-reassembly pathway for core formation.

The effects of the chemical composition and strain on the electronic properties of GaSb/InAs core-shell nanowires

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

Ning, Feng; Wang, Dan; Tang, Li-Ming, E-mail: lmtang@hnu.edu.cn

2014-09-07

The effects of the chemical composition and strain on the electronic properties of [111] zinc-blende (ZB) and [0001] wurtzite (WZ) GaSb/InAs core-shell nanowires (NWs) with different core diameters and shell thicknesses are studied using first-principles methods. The band structures of the [111] ZB GaSb/InAs core-shell NWs underwent a noticeable type-I/II band alignment transition, associated with a direct-to-indirect band gap transition under a compressive uniaxial strain. The band structures of the [0001] WZ GaSb/InAs core-shell NWs preserved the direct band gap under either compressive or tensile uniaxial strains. In addition, the band gaps and the effective masses of the carriers couldmore » be tuned by their composition. For the core-shell NWs with a fixed GaSb-core size, the band gaps decreased linearly with an increasing InAs-shell thickness, caused by the significant downshift of the conduction bands. For the [111] ZB GaSb/InAs core-shell NWs, the calculated effective masses indicated that the transport properties could be changed from hole-dominated conduction to electron-dominated conduction by changing the InAs-shell thickness.« less

A 10(9) neutrons/pulse transportable pulsed D-D neutron source based on flexible head plasma focus unit.

PubMed

Niranjan, Ram; Rout, R K; Srivastava, R; Kaushik, T C; Gupta, Satish C

2016-03-01

A 17 kJ transportable plasma focus (PF) device with flexible transmission lines is developed and is characterized. Six custom made capacitors are used for the capacitor bank (CB). The common high voltage plate of the CB is fixed to a centrally triggered spark gap switch. The output of the switch is coupled to the PF head through forty-eight 5 m long RG213 cables. The CB has a quarter time-period of 4 μs and an estimated current of 506 kA is delivered to the PF device at 17 kJ (60 μF, 24 kV) energy. The average neutron yield measured using silver activation detector in the radial direction is (7.1 ± 1.4) × 10(8) neutrons/shot over 4π sr at 5 mbar optimum D2 pressure. The average neutron yield is more in the axial direction with an anisotropy factor of 1.33 ± 0.18. The average neutron energies estimated in the axial as well as in the radial directions are (2.90 ± 0.20) MeV and (2.58 ± 0.20) MeV, respectively. The flexibility of the PF head makes it useful for many applications where the source orientation and the location are important factors. The influence of electromagnetic interferences from the CB as well as from the spark gap on applications area can be avoided by putting a suitable barrier between the bank and the PF head.

Shell Model Far From Stability: Island of Inversion Mergers

NASA Astrophysics Data System (ADS)

Nowacki, F.; Poves, A.

2018-02-01

In this study we propose a common mechanism for the disappearance of shell closures far from stabilty. With the use of Large Scale Shell Model calculations (SM-CI), we predict that the region of deformation which comprises the heaviest Chromium and Iron isotopes at and beyond N=40 will merge with a new one at N=50 in an astonishing parallel to the N=20 and N=28 case in the Neon and Magnesium isotopes. We propose a valence space including the full pf-shell for the protons and the full sdg shell for the neutrons, which represents a come-back of the the harmonic oscillator shells in the very neutron rich regime. Our calculations preserve the doubly magic nature of the ground state of 78Ni, which, however, exhibits a well deformed prolate band at low excitation energy, providing a striking example of shape coexistence far from stability. This new Island of Inversion (IoI) adds to the four well documented ones at N=8, 20, 28 and 40.

Randomized phase 2/3 trial of CpG oligodeoxynucleotide PF-3512676 alone or with dacarbazine for patients with unresectable stage III and IV melanoma.

PubMed

Weber, Jeffrey S; Zarour, Hassan; Redman, Bruce; Trefzer, Uwe; O'Day, Steven; van den Eertwegh, Alfons J M; Marshall, Ernest; Wagner, Stefan

2009-09-01

The primary objective of this phase 2 study was to assess the objective response rate (complete response [CR] + partial responses [PR]), by Response Evaluation Criteria in Solid Tumors, of PF-3512676, a CpG oligodeoxynucleotide, alone in 2 doses or in combination with dacarbazine (DTIC) in patients with unresectable stage IIIB/C or stage IV malignant melanoma, with the aim of selecting an arm to take forward to a phase 3 portion of the study. A total of 184 patients were randomized to 1 of 4 treatments: PF-3512676 10 mg (low dose), at 40 mg (high dose), 40 mg plus DTIC (850 mg/m(2)), or DTIC (850 mg/m(2)) alone. Patients received PF-3512676 subcutaneously weekly in a 3-week cycle and received DTIC intravenously on the first week of the cycle. The objective response rate (PR or CR, confirmed or unconfirmed) in the 40 mg + DTIC arm was 16% (7 patients) compared with 8% (3 patients) with DTIC alone. One (2%) patient in the 10-mg and 0 patients in the 40-mg arms achieved an objective response. Best response of CR or PR or stable disease (SD), with no minimum duration defined for SD, was achieved by 15 (33%) patients in the 40 mg + DTIC arm, 15 (38%) patients in the DTIC-only arm, 8 (17%) patients in the 10-mg arm, and 9 (20%) patients in the 40-mg arm. The most frequently reported adverse events were classified as local injection site reactions or systemic flu-like symptoms, specifically fatigue, rigors, and pyrexia. PF-3512676 at the doses used was generally well tolerated. The modest objective response rates observed in all arms did not warrant continuation to the phase 3 portion of the study.

Elevated Peak Postoperative B-type Natriuretic Peptide Predicts Decreased Longer-Term Physical Function after Primary Coronary Artery Bypass Graft Surgery

PubMed Central

Fox, Amanda A.; Marcantonio, Edward R.; Collard, Charles D.; Thoma, Mathis; Perry, Tjorvi E.; Shernan, Stanton K.; Muehlschlegel, Jochen D.; Body, Simon C.

2011-01-01

Background Elevated peak postoperative B-type natriuretic peptide (BNP) is associated with increased major adverse cardiovascular events and all-cause mortality after coronary artery bypass graft (CABG) surgery. Whether elevated postoperative BNP predicts worse post-discharge physical function (PF) is unknown. We hypothesized that peak postoperative BNP associates with PF assessed up to 2 years after CABG surgery, even after adjusting for clinical risk factors including preoperative PF. Methods This two institution prospective cohort study included patients undergoing primary CABG surgery with cardiopulmonary bypass. Short Form-36 questionnaires were administered to subjects preoperatively and 6 months, 1 and 2 years postoperatively. Short Form-36 PF domain scores were calculated using the Short Form-36 norm based scoring algorithm. Plasma BNP concentrations measured preoperatively and on postoperative days 1–5 were log10 transformed before analysis. To determine whether peak postoperative BNP independently predicts PF scores 6 months through 2 years after CABG surgery, multivariable longitudinal regression analysis of the postoperative PF scores was performed, adjusting for important clinical risk factors. Results 845 subjects (mean age±SD: 65±10 years) were analyzed. Peak postoperative BNP was significantly associated with postoperative PF (effect estimate for log10 peak BNP = −7.66 PF score points; 95% CI = −9.68, −5.64; P=<0.0001). After multivariable adjustments, peak postoperative BNP remained independently associated with postoperative PF (effect estimate for log10 peak BNP =−3.06 PF score points; 95% CI = −5.15, −0.97; P=0.004). Conclusions Elevated peak postoperative BNP independently associates with worse longer-term physical function after primary CABG surgery. Future studies are needed to determine whether medical management targeted towards reducing elevated postoperative BNP can improve PF after CABG surgery. PMID:21427536

Beta-decay strength and isospin mixing studies in the sd and fp-shells

NASA Astrophysics Data System (ADS)

Jokinen, A.; ńystö, J.; Dendooven, P.; Honkanen, A.; Lipas, P.; Peräjärvi, K.; Oinonen, M.; Siiskonen, T.

1998-12-01

We have studied beta decays of MT<0 nuclei in sd and fp shells. The decay of 41Ti shows a large, 10(8) %, isospin mixing of IAS and the Gamow-Teller strength is observed to be quenched by a factor of q2=0.64. These results can be reproduced qualitatively in our shell model calculations. We have observed for the first time proton and gamma decay of the isobaric analogue state in 23Mg. Our results on the isospin mixing of the isobaric analogue state agrees well with the shell model calculations. The obtained proton branch of the IAS is used to extract the transition strength for the reaction 22Na(p,γ)23Mg.

Effects of quantum confinement and shape on band gap of core/shell quantum dots and nanowires

NASA Astrophysics Data System (ADS)

Gao, Faming

2011-05-01

A quantum confinement model for nanocrystals developed is extended to study for the optical gap shifts in core/shell quantum dots and nanowires. The chemical bond properties and gap shifts in the InP/ZnS, CdSe/CdS, CdSe/ZnS, and CdTe/ZnS core/shell quantum dots are calculated in detail. The calculated band gaps are in excellent agreement with experimental values. The effects of structural taping and twinning on quantum confinement of InP and Si nanowires are elucidated. It is found theoretically that a competition between the positive Kubo energy-gap shift and the negative surface energy shift plays the crucial role in the optical gaps of these nanosystems.

Childhood chronic conditions and health-related quality of life: Findings from a large population-based study

PubMed Central

Bai, Guannan; Herten, Marieke Houben–van; Landgraf, Jeanne M.; Korfage, Ida J.

2017-01-01

The objective of this study was to assess the impact of health-related quality of life (HRQOL) across prevalent chronic conditions, individually and comorbid, in school-aged children in the Netherlands. 5301 children aged 4–11 years from the Dutch Health Interview Survey were included. Parents completed questionnaires regarding child and parental characteristics. HRQOL of children was measured using the Child Health Questionnaire Parent Form 28 (CHQ-PF28). Independent-t tests were used to assess differences in the mean scores of the CHQ-PF28 summary scales and profile scales between children with a prevalent chronic condition (excluding or including children with multiple chronic conditions) and children without a chronic condition. Cohen’s effect sizes (d) were calculated to assess the clinical significance of difference. The mean age of children was 7.55 (SD 2.30) years; 50.0% were boys. In children without any chronic condition, the mean score of physical summary scale (PhS) was 58.53 (SD 4.28) and mean score of the psychosocial summary scale (PsS) was 53.86 (SD 5.87). Generally, PhS and/or PsS scores in children with only one condition were lower (p<0.05) than for children without chronic conditions. When children with multiple conditions were included, mean scores of CHQ-PF28 summary and profile scales were generally lower than when they were excluded. The present study shows important information regarding the impact of prevalent chronic conditions on HRQOL in a representative population-based sample of school-aged children in the Netherlands. The information could be used for developing a more holistic approach to patient care and a surveillance framework for health promotion. PMID:28575026

High spin structure and intruder configurations in 31P

NASA Astrophysics Data System (ADS)

Ionescu-Bujor, M.; Iordachescu, A.; Napoli, D. R.; Lenzi, S. M.; Mărginean, N.; Otsuka, T.; Utsuno, Y.; Ribas, R. V.; Axiotis, M.; Bazzacco, D.; Bizzeti-Sona, A. M.; Bizzeti, P. G.; Brandolini, F.; Bucurescu, D.; Cardona, M. A.; De Angelis, G.; De Poli, M.; Della Vedova, F.; Farnea, E.; Gadea, A.; Hojman, D.; Kalfas, C. A.; Kröll, Th.; Lunardi, S.; Martínez, T.; Mason, P.; Pavan, P.; Quintana, B.; Alvarez, C. Rossi; Ur, C. A.; Vlastou, R.; Zilio, S.

2006-02-01

The nucleus 31P has been studied in the 24Mg(16O,2αp) reaction with a 70-MeV 16O beam. A complex level scheme extended up to spins 17/2+ and 15/2-, on positive and negative parity, respectively, has been established. Lifetimes for the new states have been investigated by the Doppler shift attenuation method. Two shell-model calculations have been performed to describe the experimental data, one by using the code ANTOINE in a valence space restricted to the sd shell, and the other by applying the Monte Carlo shell model in a valence space including the sd-fp shells. The latter calculation indicates that intruder excitations, involving the promotion of a T=0 proton-neutron pair to the fp shell, play a dominant role in the structure of the positive-parity high-spin states of 31P.

Non-Negative Spherical Deconvolution (NNSD) for estimation of fiber Orientation Distribution Function in single-/multi-shell diffusion MRI.

PubMed

Cheng, Jian; Deriche, Rachid; Jiang, Tianzi; Shen, Dinggang; Yap, Pew-Thian

2014-11-01

Spherical Deconvolution (SD) is commonly used for estimating fiber Orientation Distribution Functions (fODFs) from diffusion-weighted signals. Existing SD methods can be classified into two categories: 1) Continuous Representation based SD (CR-SD), where typically Spherical Harmonic (SH) representation is used for convenient analytical solutions, and 2) Discrete Representation based SD (DR-SD), where the signal profile is represented by a discrete set of basis functions uniformly oriented on the unit sphere. A feasible fODF should be non-negative and should integrate to unity throughout the unit sphere S(2). However, to our knowledge, most existing SH-based SD methods enforce non-negativity only on discretized points and not the whole continuum of S(2). Maximum Entropy SD (MESD) and Cartesian Tensor Fiber Orientation Distributions (CT-FOD) are the only SD methods that ensure non-negativity throughout the unit sphere. They are however computational intensive and are susceptible to errors caused by numerical spherical integration. Existing SD methods are also known to overestimate the number of fiber directions, especially in regions with low anisotropy. DR-SD introduces additional error in peak detection owing to the angular discretization of the unit sphere. This paper proposes a SD framework, called Non-Negative SD (NNSD), to overcome all the limitations above. NNSD is significantly less susceptible to the false-positive peaks, uses SH representation for efficient analytical spherical deconvolution, and allows accurate peak detection throughout the whole unit sphere. We further show that NNSD and most existing SD methods can be extended to work on multi-shell data by introducing a three-dimensional fiber response function. We evaluated NNSD in comparison with Constrained SD (CSD), a quadratic programming variant of CSD, MESD, and an L1-norm regularized non-negative least-squares DR-SD. Experiments on synthetic and real single-/multi-shell data indicate that NNSD improves estimation performance in terms of mean difference of angles, peak detection consistency, and anisotropy contrast between isotropic and anisotropic regions. Copyright © 2014 Elsevier Inc. All rights reserved.

A 10{sup 9} neutrons/pulse transportable pulsed D-D neutron source based on flexible head plasma focus unit

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

Niranjan, Ram, E-mail: niranjan@barc.gov.in; Rout, R. K.; Srivastava, R.

2016-03-15

A 17 kJ transportable plasma focus (PF) device with flexible transmission lines is developed and is characterized. Six custom made capacitors are used for the capacitor bank (CB). The common high voltage plate of the CB is fixed to a centrally triggered spark gap switch. The output of the switch is coupled to the PF head through forty-eight 5 m long RG213 cables. The CB has a quarter time-period of 4 μs and an estimated current of 506 kA is delivered to the PF device at 17 kJ (60 μF, 24 kV) energy. The average neutron yield measured using silvermore » activation detector in the radial direction is (7.1 ± 1.4) × 10{sup 8} neutrons/shot over 4π sr at 5 mbar optimum D{sub 2} pressure. The average neutron yield is more in the axial direction with an anisotropy factor of 1.33 ± 0.18. The average neutron energies estimated in the axial as well as in the radial directions are (2.90 ± 0.20) MeV and (2.58 ± 0.20) MeV, respectively. The flexibility of the PF head makes it useful for many applications where the source orientation and the location are important factors. The influence of electromagnetic interferences from the CB as well as from the spark gap on applications area can be avoided by putting a suitable barrier between the bank and the PF head.« less

X-Divertors on ITER - with no hardware changes

NASA Astrophysics Data System (ADS)

Valanju, Prashant; Covele, Brent; Kotschenreuther, Mike; Mahajan, Swadesh; Kessel, Charles

2014-10-01

Using CORSICA, we have discovered that X-Divertor (XD) equilibria are possible on ITER - without any extra PF coils inside the TF coils, and with no changes to ITER's poloidal field (PF) coil set, divertor cassette, strike points, or first wall. Starting from the Standard Divertor (SD), a sequence of XD configurations (with increasing flux expansions at the divertor plate) can be made by reprogramming ITER PF coil currents while keeping them all under their design limits (Lackner and Zohm have shown this to be impossible for Snowflakes). The strike point is held fixed, so no changes in the divertor or pumping hardware will be needed. The main plasma shape is kept very close to the SD case, so no hardware changes to the main chamber will be needed. Time-dependent ITER-XD operational scenarios are being checked using TSC. This opens the possibility that many XDs could be tested and used to assist in high-power operation on ITER. Because of the toroidally segmented ITER divertor plates, strongly detached operation may be critical for making use of the largest XD flux expansion possible. The flux flaring in XDs is expected to increase the stability of detachment, so that H-mode confinement is not affected. Detachment stability is being examined with SOLPS. This work supported by US DOE Grants DE-FG02-04ER54742 and DE-FG02-04ER54754 and by TACC at UT Austin.

New evaluation parameter for wearable thermoelectric generators

NASA Astrophysics Data System (ADS)

Wijethunge, Dimuthu; Kim, Woochul

2018-04-01

Wearable devices constitute a key application area for thermoelectric devices. However, owing to new constraints in wearable applications, a few conventional device optimization techniques are not appropriate and material evaluation parameters, such as figure of merit (zT) and power factor (PF), tend to be inadequate. We illustrated the incompleteness of zT and PF by performing simulations and considering different thermoelectric materials. The results indicate a weak correlation between device performance and zT and PF. In this study, we propose a new evaluation parameter, zTwearable, which is better suited for wearable applications compared to conventional zT. Owing to size restrictions, gap filler based device optimization is extremely critical in wearable devices. With respect to the occasions in which gap fillers are used, expressions for power, effective thermal conductivity (keff), and optimum load electrical ratio (mopt) are derived. According to the new parameters, the thermal conductivity of the material has become much more critical now. The proposed new evaluation parameter, namely, zTwearable, is extremely useful in the selection of an appropriate thermoelectric material among various candidates prior to the commencement of the actual design process.

Li+ solvation and kinetics of Li+-BF4-/PF6- ion pairs in ethylene carbonate. A molecular dynamics study with classical rate theories

NASA Astrophysics Data System (ADS)

Chang, Tsun-Mei; Dang, Liem X.

2017-10-01

Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ethylene carbonate (EC) exchange process between the first and second solvation shells around Li+ and the dissociation kinetics of ion pairs Li+-[BF4] and Li+-[PF6] in this solvent. We calculate the exchange rates using transition state theory and correct them with transmission coefficients computed by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found that the residence times of EC around Li+ ions varied from 60 to 450 ps, depending on the correction method used. We found that the relaxation times changed significantly from Li+-[BF4] to Li+-[PF6] ion pairs in EC. Our results also show that, in addition to affecting the free energy of dissociation in EC, the anion type also significantly influences the dissociation kinetics of ion pairing.

Harnessing the bistable composite shells to design a tunable phononic band gap structure

NASA Astrophysics Data System (ADS)

Li, Yi; Xu, Yanlong

2018-02-01

By proposing a system composed of an array of bistable composite shells immersed in air, we develop a new class of periodic structure to control the propagation of sound. Through numerical investigation, we find that the acoustic band gap of this system can be switched on and off by triggering the snap through deformation of the bistable composite shells. The shape of cross section and filling fraction of unit cell can be altered by different number of bistable composite shells, and they have strong impact on the position and width of the band gap. The proposed concept paves the way of using the bistable structures to design a new class of metamaterials that can be enable to manipulate sound.

Type I band alignment in GaAs{sub 81}Sb{sub 19}/GaAs core-shell nanowires

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

Xu, T.; Key Laboratory of Advanced Display and System Application, Shanghai University, 149 Yanchang Road, Shanghai 200072; Wei, M. J.

2015-09-14

The composition and band gap of the shell that formed during the growth of axial GaAs/GaAs{sub 81}Sb{sub 19}/ GaAs heterostructure nanowires have been investigated by transmission electron microscopy combined with energy dispersion spectroscopy, scanning tunneling spectroscopy, and density functional theory calculations. On the GaAs{sub 81}Sb{sub 19} intermediate segment, the shell is found to be free of Sb (pure GaAs shell) and transparent to the tunneling electrons, despite the (110) biaxial strain that affects its band gap. As a result, a direct measurement of the core band gap allows the quantitative determination of the band offset between the GaAs{sub 81}Sb{sub 19}more » core and the GaAs shell and identifies it as a type I band alignment.« less

Diurnal variations of summer precipitation over the regions east to Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wu, Yang; Huang, Anning; Huang, Danqing; Chen, Fei; Yang, Ben; Zhou, Yang; Fang, Dexian; Zhang, Lujun; Wen, Lijuan

2017-12-01

Based on the hourly gauge-satellite merged precipitation product with the horizontal resolution of 0.1° latitude/longitude during 2008-2014, diurnal variations of the summer precipitation amount (PA), frequency (PF), and intensity (PI) with different duration time over the regions east to Tibetan Plateau have been systematically revealed in this study. Results indicate that the eight typical precipitation diurnal patterns identified by the cluster analysis display pronounced regional features among the plateaus, basins, plains, hilly and coastal areas. The precipitation diurnal cycles are significantly affected by the sub-grid terrain fluctuations. The PA, PF and PI of the total rainfall show much more pronounced double diurnal peaks with the sub-grid topography standard deviation (SD) decreased. Meanwhile, the diurnal peaks of PA and PF (PI) strengthen (weaken) with the sub-grid topography SD enhanced. Over the elevated mountain ranges, southeastern hilly and coastal regions, the PA and PF diurnal patterns of the total rainfall generally show predominant late-afternoon peaks, which are closely associated with the short-duration (≤slant 3 h) rainfall. Along the Tibetan Plateau to its downstream, the diurnal peaks of PA, PF and PI for the total rainfall all exhibit obvious eastward phase time delay mainly due to the diurnal evolutions of long-duration (> 6 h) rainfall. However, the 4-6 h rainfall leads to the eastward phase time delay of the total rainfall along the Taihang Mountains to its downstream. Further mechanism analysis suggests that the midnight to morning diurnal evolution of the long-duration rainfall is closely associated with the diurnal variations of the upward branches of thermally driven mountain-plain solenoids and the water vapor transport associated with the accelerated nocturnal southwesterly winds. The late-afternoon peak of the short-duration PA over the southeastern hilly and coastal regions is ascribed to the strong local thermal convections due to the solar heating in afternoon, while the early-evening peak of the short-duration PA over the elevated mountain ranges is significantly contributed by the upward warm-moist wind from the surrounding low-lying basins or plains.

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

Orce, J. N.; McKay, C. J.; Lesher, S. R.

A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2{sub T=1}{sup +} state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2{sub T=1}{sup +} state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for themore » A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 2{sub 1(T=1)}{sup +} {yields} 0{sub 1(T=1)}{sup +} transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.« less

Association of baseline knee sagittal dynamic joint stiffness during gait and 2-year patellofemoral cartilage damage worsening in knee osteoarthritis.

PubMed

Chang, A H; Chmiel, J S; Almagor, O; Guermazi, A; Prasad, P V; Moisio, K C; Belisle, L; Zhang, Y; Hayes, K; Sharma, L

2017-02-01

Knee sagittal dynamic joint stiffness (DJS) describes the biomechanical interaction between change in external knee flexion moment and flexion angular excursion during gait. In theory, greater DJS may particularly stress the patellofemoral (PF) compartment and thereby contribute to PF osteoarthritis (OA) worsening. We hypothesized that greater baseline knee sagittal DJS is associated with PF cartilage damage worsening 2 years later. Participants all had OA in at least one knee. Knee kinematics and kinetics during gait were recorded using motion capture systems and force plates. Knee sagittal DJS was computed as the slope of the linear regression line for knee flexion moments vs angles during the loading response phase. Knee magnetic resonance imaging (MRI) scans were obtained at baseline and 2 years later. We assessed the association between baseline DJS and baseline-to-2-year PF cartilage damage worsening using logistic regression with generalized estimating equations (GEE). Our sample had 391 knees (204 persons): mean age 64.2 years (SD 10.0); body mass index (BMI) 28.4 kg/m 2 (5.7); 76.5% women. Baseline knee sagittal DJS was associated with baseline-to-2-year cartilage damage worsening in the lateral (OR = 5.35, 95% CI: 2.37-12.05) and any PF (OR = 2.99, 95% CI: 1.27-7.04) compartment. Individual components of baseline DJS (i.e., change in knee moment or angle) were not associated with subsequent PF disease worsening. Capturing the concomitant effect of knee kinetics and kinematics during gait, knee sagittal DJS is a potentially modifiable risk factor for PF disease worsening. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Association of Baseline Knee Sagittal Dynamic Joint Stiffness during Gait and 2-year Patellofemoral Cartilage Damage Worsening in Knee Osteoarthritis

PubMed Central

Chang, Alison H.; Chmiel, Joan S.; Almagor, Orit; Guermazi, Ali; Prasad, Pottumarthi V.; Moisio, Kirsten C.; Belisle, Laura; Zhang, Yunhui; Hayes, Karen; Sharma, Leena

2016-01-01

Objective Knee sagittal dynamic joint stiffness (DJS) describes the biomechanical interaction between change in external knee flexion moment and flexion angular excursion during gait. In theory, greater DJS may particularly stress the patellofemoral (PF) compartment and thereby contribute to PF osteoarthritis (OA) worsening. We hypothesized that greater baseline knee sagittal DJS is associated with PF cartilage damage worsening 2 years later. Methods Participants all had OA in at least one knee. Knee kinematics and kinetics during gait were recorded using motion capture systems and force plates. Knee sagittal DJS was computed as the slope of the linear regression line for knee flexion moments vs. angles during the loading response phase. Knee MRI scans were obtained at baseline and 2 years later. We assessed the association between baseline DJS and baseline-to-2-year PF cartilage damage worsening using logistic regression with generalized estimating equations. Results Our sample had 391 knees (204 persons): mean age 64.2 years (SD 10.0); BMI 28.4 kg/m2 (5.7); 76.5% women. Baseline knee sagittal DJS was associated with baseline-to-2-year cartilage damage worsening in the lateral (OR=5.35, 95% CI: 2.37–12.05) and any PF (OR=2.99, 95% CI: 1.27–7.04) compartment. Individual components of baseline DJS (i.e., change in knee moment or angle) were not associated with subsequent PF disease worsening. Conclusion Capturing the concomitant effect of knee kinetics and kinematics during gait, knee sagittal DJS is a potentially modifiable risk factor for PF disease worsening. PMID:27729289

Open sd-shell nuclei from first principles

DOE PAGES

Jansen, Gustav R.; Signoracci, Angelo J.; Hagen, Gaute; ...

2016-07-05

We extend the ab initio coupled-cluster effective interaction (CCEI) method to open-shell nuclei with protons and neutrons in the valence space, and compute binding energies and excited states of isotopes of neon and magnesium. We employ a nucleon-nucleon and three-nucleon interaction from chiral effective field theory evolved to a lower cutoff via a similarity renormalization group transformation. We find good agreement with experiment for binding energies and spectra, while charge radii of neon isotopes are underestimated. For the deformed nuclei 20Ne and 24Mg we reproduce rotational bands and electric quadrupole transitions within uncertainties estimated from an effective field theory formore » deformed nuclei, thereby demonstrating that collective phenomena in sd-shell nuclei emerge from complex ab initio calculations.« less

Open sd-shell nuclei from first principles

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

Jansen, Gustav R.; Signoracci, Angelo J.; Hagen, Gaute

We extend the ab initio coupled-cluster effective interaction (CCEI) method to open-shell nuclei with protons and neutrons in the valence space, and compute binding energies and excited states of isotopes of neon and magnesium. We employ a nucleon-nucleon and three-nucleon interaction from chiral effective field theory evolved to a lower cutoff via a similarity renormalization group transformation. We find good agreement with experiment for binding energies and spectra, while charge radii of neon isotopes are underestimated. For the deformed nuclei 20Ne and 24Mg we reproduce rotational bands and electric quadrupole transitions within uncertainties estimated from an effective field theory formore » deformed nuclei, thereby demonstrating that collective phenomena in sd-shell nuclei emerge from complex ab initio calculations.« less

Insights into the Performance of SD Bioline Malaria Ag P.f/Pan Rapid Diagnostic Test and Plasmodium falciparum Histidine-Rich Protein 2 Gene Variation in Madagascar.

PubMed

Willie, Nigani; Mehlotra, Rajeev K; Howes, Rosalind E; Rakotomanga, Tovonahary A; Ramboarina, Stephanie; Ratsimbasoa, Arsène C; Zimmerman, Peter A

2018-06-01

Plasmodium falciparum histidine-rich protein 2 (PfHRP2) forms the basis of many current malaria rapid diagnostic tests (RDTs). However, the parasites lacking part or all of the pfhrp2 gene do not express the PfHRP2 protein and are, therefore, not identifiable by PfHRP2-detecting RDTs. We evaluated the performance of the SD Bioline Malaria Ag P.f/Pan RDT together with pfhrp2 variation in Madagascar. Genomic DNA isolated from 260 patient blood samples were polymerase chain reaction (PCR)-amplified for the parasite 18S rRNA and pfhrp2 genes. Post-PCR ligation detection reaction-fluorescent microsphere assay (LDR-FMA) was performed for the identification of parasite species. Plasmodium falciparum histidine-rich protein 2 amplicons were sequenced. Polymerase chain reaction diagnosis of patient samples showed that 29% (75/260) were infected and P. falciparum was present in 95% (71/75) of these PCR-positive samples. Comparing RDT and P. falciparum detection by LDR-FMA, eight samples were RDT negative but P. falciparum positive (false negatives), all of which were pfhrp2 positive. The sensitivity and specificity of the RDT were 87% and 90%, respectively. Seventy-three samples were amplified for pfhrp2 , from which nine randomly selected amplicons were sequenced, yielding 13 sequences. Amplification of pfhrp2 , combined with RDT analysis and P. falciparum detection by LDR-FMA, showed that there was no indication of pfhrp2 deletion. Sequence analysis of pfhrp2 showed that the correlation between pfhrp2 sequence structure and RDT detection rates was unclear. Although the observed absence of pfhrp2 deletion from the samples screened here is encouraging, continued monitoring of the efficacy of the SD Bioline Malaria Ag P.f/Pan RDT for malaria diagnosis in Madagascar is warranted.

Inner-shell excitation and ionic fragmentation of molecules

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

Hitchcock, A.P.; Tyliszczak, T.; Cavell, R.G.

1997-04-01

Inner-shell excitation and associated decay spectroscopies are site specific probes of electronic and geometrical structure and photoionization dynamics. X-ray absorption probes the geometric and electronic structure, while time-of-flight mass spectrometry with multi-coincidence detection provides information on the photofragmentation dynamics of the initially produced inner-shell state. Auger decay of inner-shell excited and ionised states is an efficient source of multiply charged ions. The charge separation and fragmentation of these species, studied by photoelectron-photoion-photoion coincidence (also called charge separation mass spectrometry) gives insights into bonding and electronic structure. In molecules, the dependence of the fragmentation process on the X-ray energy can revealmore » cases of site and/or state selective fragmentation. At the ALS the authors have examined the soft X-ray spectroscopy and ionic fragmentation of a number of molecules, including carboranes, silylenes, phosphorus halides, SF{sub 6} and CO{sub 2}. Their work is illustrated using results from the carborane and PF{sub 3} studies.« less

In situ passivation of GaAsP nanowires.

PubMed

Himwas, C; Collin, S; Rale, P; Chauvin, N; Patriarche, G; Oehler, F; Julien, F H; Travers, L; Harmand, J-C; Tchernycheva, M

2017-12-08

We report on the structural and optical properties of GaAsP nanowires (NWs) grown by molecular-beam epitaxy. By adjusting the alloy composition in the NWs, the transition energy was tuned to the optimal value required for tandem III-V/silicon solar cells. We discovered that an unintentional shell was also formed during the GaAsP NW growth. The NW surface was passivated by an in situ deposition of a radial Ga(As)P shell. Different shell compositions and thicknesses were investigated. We demonstrate that the optimal passivation conditions for GaAsP NWs (with a gap of 1.78 eV) are obtained with a 5 nm thick GaP shell. This passivation enhances the luminescence intensity of the NWs by 2 orders of magnitude and yields a longer luminescence decay. The luminescence dynamics changes from single exponential decay with a 4 ps characteristic time in non-passivated NWs to a bi-exponential decay with characteristic times of 85 and 540 ps in NWs with GaP shell passivation.

Li + solvation and kinetics of Li +–BF 4 -/PF 6 - ion pairs in ethylene carbonate. A molecular dynamics study with classical rate theories

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

Chang, Tsun-Mei; Dang, Liem X.

Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine in this paper the ethylene carbonate (EC) exchange process between the first and second solvation shells around Li + and the dissociation kinetics of ion pairs Li +–[BF 4] and Li +–[PF 6] in this solvent. We calculate the exchange rates using transition state theory and correct them with transmission coefficients computed by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found that the residence times of EC around Li + ions varied from 60 to 450 ps, depending on themore » correction method used. We found that the relaxation times changed significantly from Li +–[BF 4] to Li +–[PF 6] ion pairs in EC. Finally, our results also show that, in addition to affecting the free energy of dissociation in EC, the anion type also significantly influences the dissociation kinetics of ion pairing.« less

Li + solvation and kinetics of Li +–BF 4 -/PF 6 - ion pairs in ethylene carbonate. A molecular dynamics study with classical rate theories

DOE PAGES

Chang, Tsun-Mei; Dang, Liem X.

2017-07-19

Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine in this paper the ethylene carbonate (EC) exchange process between the first and second solvation shells around Li + and the dissociation kinetics of ion pairs Li +–[BF 4] and Li +–[PF 6] in this solvent. We calculate the exchange rates using transition state theory and correct them with transmission coefficients computed by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found that the residence times of EC around Li + ions varied from 60 to 450 ps, depending on themore » correction method used. We found that the relaxation times changed significantly from Li +–[BF 4] to Li +–[PF 6] ion pairs in EC. Finally, our results also show that, in addition to affecting the free energy of dissociation in EC, the anion type also significantly influences the dissociation kinetics of ion pairing.« less

A comparative study on the effects of amphiphilic and hydrophilic polymers on the release profiles of a poorly water-soluble drug.

PubMed

Irwan, Anastasia W; Berania, Jacqueline E; Liu, Xueming

2016-03-01

This paper reports the use of two crystalline polymers, an amphiphilic Pluronic® F-127 (PF-127) and a hydrophilic poly(ethylene glycol) (PEG6000) as drug delivery carriers for improving the drug release of a poorly water-soluble drug, fenofibrate (FEN), via micelle formation and formation of a solid dispersion (SD). In 10% PF-127 (aq.), FEN showed an equilibrium solubility of ca. 0.6 mg/mL, due to micelle formation. In contrast, in 10% PEG6000 (aq.), FEN only exhibited an equilibrium solubility of 0.0037 mg/mL. FEN-loaded micelles in PF-127 were prepared by direct dissolution and membrane dialysis. Both methods only yielded a highest drug loading (DL) of 0.5%. SDs of FEN in PF-127 and PEG6000, at DLs of 5-80%, were prepared by solvent evaporation. In-vitro dissolution testing showed that both micelles and SDs significantly improved FEN's release rate. The SDs of FEN in PF-127 showed significantly faster release than crystalline FEN, when the DL was as high as 50%, whereas SDs of PEG6000 showed similar enhancement in the release rate when the DL was not more than 20%. The DSC thermograms of SDs of PF-127 exhibited a single phase transition peak at ca. 55-57 °C when the DL was not more than 50%, whereas those in PEG6000 exhibited a similar peak at ca. 61-63 °C when the DL was not more than 35%. When the DL exceeded 50% for SDs of PF-127 and 35% for SDs of PEG6000, DSC thermograms showed two melting peaks for the carrier polymer and FEN, respectively. FT-IR studies revealed that PF-127 has a stronger hydrophobic-hydrophobic interaction with FEN than PEG6000. It is likely that both dispersion and micelle formation contributed to the stronger effect of PF-127 on enhancing the release rate of FEN in its SDs.

Vibration isolation design for periodically stiffened shells by the wave finite element method

NASA Astrophysics Data System (ADS)

Hong, Jie; He, Xueqing; Zhang, Dayi; Zhang, Bing; Ma, Yanhong

2018-04-01

Periodically stiffened shell structures are widely used due to their excellent specific strength, in particular for aeronautical and astronautical components. This paper presents an improved Wave Finite Element Method (FEM) that can be employed to predict the band-gap characteristics of stiffened shell structures efficiently. An aero-engine casing, which is a typical periodically stiffened shell structure, was employed to verify the validation and efficiency of the Wave FEM. Good agreement has been found between the Wave FEM and the classical FEM for different boundary conditions. One effective wave selection method based on the Wave FEM has thus been put forward to filter the radial modes of a shell structure. Furthermore, an optimisation strategy by the combination of the Wave FEM and genetic algorithm was presented for periodically stiffened shell structures. The optimal out-of-plane band gap and the mass of the whole structure can be achieved by the optimisation strategy under an aerodynamic load. Results also indicate that geometric parameters of stiffeners can be properly selected that the out-of-plane vibration attenuates significantly in the frequency band of interest. This study can provide valuable references for designing the band gaps of vibration isolation.

IMPACT OF NEW GAMOW–TELLER STRENGTHS ON EXPLOSIVE TYPE IA SUPERNOVA NUCLEOSYNTHESIS

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

Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka

2016-12-20

Recent experimental results have confirmed a possible reduction in the Gamow–Teller (GT{sub +}) strengths of pf-shell nuclei. These proton-rich nuclei are of relevance in the deflagration and explosive burning phases of SNe Ia. While prior GT strengths result in nucleosynthesis predictions with a lower-than-expected electron fraction, a reduction in the GT{sub +} strength can result in a slightly increased electron fraction compared to previous shell model predictions, though the enhancement is not as large as previous enhancements in going from rates computed by Fuller, Fowler, and Newman based on an independent particle model. A shell model parametrization has been developed thatmore » more closely matches experimental GT strengths. The resultant electron-capture rates are used in nucleosynthesis calculations for carbon deflagration and explosion phases of SNe Ia, and the final mass fractions are compared to those obtained using more commonly used rates.« less

Strongly screening corrections to antineutrino energy loss by β --decay of nuclides 53Fe, 54Fe, 55Fe, and 56Fe in supernova

NASA Astrophysics Data System (ADS)

Liu, Jing-Jing; Liu, Dong-Mei

2018-06-01

Based on the p-f shell-model, we discuss and calculate β--decay half-lives of neutron-rich nuclei, with a consideration of shell and pair effects, the decay energy, and the nucleon numbers. According to the linear response theory model, we study the effect of electron screening on the electron energy, beta-decay threshold energy, and the antineutrino energy loss rate by β--decay of some iron isotopes. We find that the electron screening antineutrino energy loss rates increase by about two orders of magnitude due to the shell effects and the pairing effect. Beta-decay rates with Q-value corrections due to strong electron screening are higher than those without the Q-value corrections by more than two orders of magnitude. Our conclusions may be helpful for the research on numerical simulations of the cooling of stars.

Impact of New Gamow-Teller Strengths on Explosive Type Ia Supernova Nucleosynthesis

NASA Astrophysics Data System (ADS)

Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka; Suzuki, Toshio; Hidaka, Jun; Honma, Michio; Iwamoto, Koichi; Nomoto, Ken'ichi; Otsuka, Takaharu

2016-12-01

Recent experimental results have confirmed a possible reduction in the Gamow-Teller (GT+) strengths of pf-shell nuclei. These proton-rich nuclei are of relevance in the deflagration and explosive burning phases of SNe Ia. While prior GT strengths result in nucleosynthesis predictions with a lower-than-expected electron fraction, a reduction in the GT+ strength can result in a slightly increased electron fraction compared to previous shell model predictions, though the enhancement is not as large as previous enhancements in going from rates computed by Fuller, Fowler, and Newman based on an independent particle model. A shell model parametrization has been developed that more closely matches experimental GT strengths. The resultant electron-capture rates are used in nucleosynthesis calculations for carbon deflagration and explosion phases of SNe Ia, and the final mass fractions are compared to those obtained using more commonly used rates.

Atomistic tight-binding theory of excitonic splitting energies in CdX(X = Se, S and Te)/ZnS core/shell nanocrystals

NASA Astrophysics Data System (ADS)

Sukkabot, Worasak; Pinsook, Udomsilp

2017-01-01

Using the atomistic tight-binding theory (TB) and a configuration interaction description (CI), we numerically compute the excitonic splitting of CdX(X = Se, S and Te)/ZnS core/shell nanocrystals with the objective to explain how types of the core materials and growth shell thickness can provide the detailed manipulation of the dark-dark (DD), dark-bright (DB) and bright-bright (BB) excitonic splitting, beneficial for the active application of quantum information. To analyze the splitting of the excitonic states, the optical band gaps, ground-state wave function overlaps and atomistic electron-hole interactions tend to be numerically demonstrated. Based on the atomistic computations, the single-particle and excitonic gaps are mainly reduced with the increasing ZnS shell thickness owing to the quantum confinement. In the range of the higher to lower energies, the order of the single-particle gaps is CdSe/ZnS, CdS/ZnS and CdTe/ZnS core/shell nanocrystals, while one of the excitonic gaps is CdS/ZnS, CdSe/ZnS and CdTe/ZnS core/shell nanocrystals because of the atomistic electron-hole interaction. The strongest electron-hole interactions are mainly observed in CdSe/ZnS core/shell nanocrystals. In addition, the computational results underline that the energies of the dark-dark (DD), dark-bright (DB) and bright-bright (BB) excitonic splitting are generally reduced with the increasing ZnS growth shell thickness as described by the trend of the electron-hole exchange interaction. The high-to-low splitting of the excitonic states is demonstrated in CdSe/ZnS, CdTe/ZnS and CdS/ZnS core/shell nanocrystals because of the fashion in the electron-hole exchange interaction and overlaps of the electron-hole wave functions. As the resulting calculations, it is expected that CdS/ZnS core/shell nanocrystals are the best candidates to be the source of entangled photons. Finally, the comprehensive information on the excitonic splitting can enable the use of suitable core/shell nanocrystals for the entangled photons in the application of quantum information.

Functional Independence in Late-Life: Maintaining Physical Functioning in Older Adulthood Predicts Daily Life Function after Age 80

PubMed Central

Leng, Xiaoyan; La Monte, Michael J.; Tindle, Hilary A.; Cochrane, Barbara B.; Shumaker, Sally A.

2016-01-01

Abstract Background. We examined physical functioning (PF) trajectories (maintaining, slowly declining, and rapidly declining) spanning 15 years in older women aged 65–80 and protective factors that predicted better current levels and less decline in functional independence outcomes after age 80. Methods. Women’s Health Initiative extension participants who met criteria (enrolled in either the clinical trial or observational study cohort, >80 years at the data release cutoff, PF survey data from initial enrollment to age 80, and functional independence survey data after age 80) were included in these analyses (mean [ SD ] age = 84.0 [1.4] years; N = 10,478). PF was measured with the SF-36 (mean = 4.9 occasions). Functional independence was measured by self-reported level of dependence in basic and instrumental activities of daily living (ADLs and IADLs) (mean = 3.4 and 3.3 occasions). Results. Maintaining consistent PF in older adulthood extends functional independence in ADL and IADL in late-life. Protective factors shared by ADL and IADL include maintaining PF over time, self-reported excellent or very good health, no history of hip fracture after age 55, and no history of cardiovascular disease. Better IADL function is uniquely predicted by a body mass index less than 25 and no depression. Less ADL and IADL decline is predicted by better self-reported health, and less IADL decline is uniquely predicted by having no history of hip fracture after age 55. Conclusions. Maintaining or improving PF and preventing injury and disease in older adulthood (ages 65–80) has far-reaching implications for improving late-life (after age 80) functional independence. PMID:26858328

Functional Independence in Late-Life: Maintaining Physical Functioning in Older Adulthood Predicts Daily Life Function after Age 80.

PubMed

Vaughan, Leslie; Leng, Xiaoyan; La Monte, Michael J; Tindle, Hilary A; Cochrane, Barbara B; Shumaker, Sally A

2016-03-01

We examined physical functioning (PF) trajectories (maintaining, slowly declining, and rapidly declining) spanning 15 years in older women aged 65-80 and protective factors that predicted better current levels and less decline in functional independence outcomes after age 80. Women's Health Initiative extension participants who met criteria (enrolled in either the clinical trial or observational study cohort, >80 years at the data release cutoff, PF survey data from initial enrollment to age 80, and functional independence survey data after age 80) were included in these analyses (mean [SD] age = 84.0 [1.4] years; N = 10,478). PF was measured with the SF-36 (mean = 4.9 occasions). Functional independence was measured by self-reported level of dependence in basic and instrumental activities of daily living (ADLs and IADLs) (mean = 3.4 and 3.3 occasions). Maintaining consistent PF in older adulthood extends functional independence in ADL and IADL in late-life. Protective factors shared by ADL and IADL include maintaining PF over time, self-reported excellent or very good health, no history of hip fracture after age 55, and no history of cardiovascular disease. Better IADL function is uniquely predicted by a body mass index less than 25 and no depression. Less ADL and IADL decline is predicted by better self-reported health, and less IADL decline is uniquely predicted by having no history of hip fracture after age 55. Maintaining or improving PF and preventing injury and disease in older adulthood (ages 65-80) has far-reaching implications for improving late-life (after age 80) functional independence. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cross-cultural Adaptation and Validation of the Victorian Institute of Sport Assessment-Patella Questionnaire for French-Speaking Patients With Patellar Tendinopathy.

PubMed

Kaux, Jean-François; Delvaux, François; Oppong-Kyei, Julian; Beaudart, Charlotte; Buckinx, Fanny; Croisier, Jean-Louis; Forthomme, Bénédicte; Crielaard, Jean-Michel; Bruyère, Olivier

2016-05-01

Study Design Clinical measurement study. Background The Victorian Institute of Sport Assessment-Patella (VISA-P), originally developed in English, assesses the severity of patellar tendinopathy symptoms. To date, no French version of the questionnaire exists. Objectives The aim of our study was to translate the VISA-P into French and verify its psychometric properties. Methods The translation and cultural adaptation were performed according to international recommendations in 6 steps: initial translation, translation merging, back translation to the original language, use of an expert committee to reach a prefinal version, test of the prefinal version, and expert committee appraisal of a final version. Afterward, the psychometric properties of the final French version (VISA-PF) were assessed in 92 subjects, divided into 3 groups: pathological subjects (n = 28), asymptomatic subjects (n = 22), and sports-risk subjects (n = 42). Results All members of the expert committee agreed with the final version. On a scale ranging from 0 to 100, with 100 representing an asymptomatic subject, the average ± SD scores on the VISA-PF were 53 ± 17 for the pathological group, 99 ± 2 for the healthy group, and 86 ± 14 for the sports-risk group. The test-retest reliability of the VISA-PF was excellent, with good internal consistency. Correlations between the VISA-PF and divergent validity of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) were low, and the correlation coefficient values measured between the VISA-PF scores and converged items of the SF-36 were higher. Conclusion The VISA-PF is understandable, valid, and suitable for French-speaking patients with patellar tendinopathy. J Orthop Sports Phys Ther 2016;46(5):384-390. Epub 21 Mar 2016. doi:10.2519/jospt.2016.5937.

Relationships Between Concentric and Eccentric Strength and Countermovement Jump Performance in Resistance Trained Men.

PubMed

Bridgeman, Lee A; McGuigan, Michael R; Gill, Nicholas D; Dulson, Deborah K

2018-01-01

Bridgeman, LA, McGuigan, MR, Gill, ND, and Dulson, DK. Relationships between concentric and eccentric strength and countermovement jump performance in resistance trained men. J Strength Cond Res 32(1): 255-260, 2018-The purpose of this study was to investigate the relationships between concentric and eccentric peak force (PF) and countermovement jump (CMJ) performance in resistance trained men. Subjects were 12 men (mean ± SD; age: 25.4 ± 3.5 years; height: 177.2 ± 4.5 cm; mass: 84.0 ± 10.1 kg). The men were tested for concentric and eccentric PF using the Exerbotics squat device. Subjects then completed 3 CMJs to allow for the calculation of peak power (PP), peak ground reaction force, and jump height (JH). Correlations between the variables of interest were calculated using Pearson product-moment correlation coefficients. A large relationship was found between absolute concentric PF and absolute CMJ PP (r = 0.66, p ≤ 0.05). Absolute eccentric PF had a very large relationship with absolute CMJ PP and CMJ JH (r = 0.74, p < 0.01 and r = 0.74, p < 0.001, respectively). In addition, absolute eccentric PF was found to have a moderate relationship with relative CMJ PP (r = 0.58, p ≤ 0.05). Relative eccentric PF was had a very large relationship with relative CMJ PP and CMJ JH (r = 0.73, p < 0.001 and r = 0.79, p < 0.001, respectively). Based on these findings, strength and conditioning coaches and athletes who wish to enhance CMJ performance may wish to include exercises, which enhance lower-body eccentric strength within their training.

Plate/shell structure topology optimization of orthotropic material for buckling problem based on independent continuous topological variables

NASA Astrophysics Data System (ADS)

Ye, Hong-Ling; Wang, Wei-Wei; Chen, Ning; Sui, Yun-Kang

2017-10-01

The purpose of the present work is to study the buckling problem with plate/shell topology optimization of orthotropic material. A model of buckling topology optimization is established based on the independent, continuous, and mapping method, which considers structural mass as objective and buckling critical loads as constraints. Firstly, composite exponential function (CEF) and power function (PF) as filter functions are introduced to recognize the element mass, the element stiffness matrix, and the element geometric stiffness matrix. The filter functions of the orthotropic material stiffness are deduced. Then these filter functions are put into buckling topology optimization of a differential equation to analyze the design sensitivity. Furthermore, the buckling constraints are approximately expressed as explicit functions with respect to the design variables based on the first-order Taylor expansion. The objective function is standardized based on the second-order Taylor expansion. Therefore, the optimization model is translated into a quadratic program. Finally, the dual sequence quadratic programming (DSQP) algorithm and the global convergence method of moving asymptotes algorithm with two different filter functions (CEF and PF) are applied to solve the optimal model. Three numerical results show that DSQP&CEF has the best performance in the view of structural mass and discretion.

Lithium ion solvation and diffusion in bulk organic electrolytes from first-principles and classical reactive molecular dynamics.

PubMed

Ong, Mitchell T; Verners, Osvalds; Draeger, Erik W; van Duin, Adri C T; Lordi, Vincenzo; Pask, John E

2015-01-29

Lithium-ion battery performance is strongly influenced by the ionic conductivity of the electrolyte, which depends on the speed at which Li ions migrate across the cell and relates to their solvation structure. The choice of solvent can greatly impact both the solvation and diffusivity of Li ions. In this work, we used first-principles molecular dynamics to examine the solvation and diffusion of Li ions in the bulk organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC), and a mixture of EC and EMC. We found that Li ions are solvated by either carbonyl or ether oxygen atoms of the solvents and sometimes by the PF6(-) anion. Li(+) prefers a tetrahedrally coordinated first solvation shell regardless of which species are involved, with the specific preferred solvation structure dependent on the organic solvent. In addition, we calculated Li diffusion coefficients in each electrolyte, finding slightly larger diffusivities in the linear carbonate EMC compared to the cyclic carbonate EC. The magnitude of the diffusion coefficient correlates with the strength of Li(+) solvation. Corresponding analysis for the PF6(-) anion shows greater diffusivity associated with a weakly bound, poorly defined first solvation shell. These results can be used to aid in the design of new electrolytes to improve Li-ion battery performance.

The selfish Segregation Distorter gene complex of Drosophila melanogaster.

PubMed

Larracuente, Amanda M; Presgraves, Daven C

2012-09-01

Segregation Distorter (SD) is an autosomal meiotic drive gene complex found worldwide in natural populations of Drosophila melanogaster. During spermatogenesis, SD induces dysfunction of SD(+) spermatids so that SD/SD(+) males sire almost exclusively SD-bearing progeny rather than the expected 1:1 Mendelian ratio. SD is thus evolutionarily "selfish," enhancing its own transmission at the expense of its bearers. Here we review the molecular and evolutionary genetics of SD. Genetic analyses show that the SD is a multilocus gene complex involving two key loci--the driver, Segregation distorter (Sd), and the target of drive, Responder (Rsp)--and at least three upward modifiers of distortion. Molecular analyses show that Sd encodes a truncated duplication of the gene RanGAP, whereas Rsp is a large pericentromeric block of satellite DNA. The Sd-RanGAP protein is enzymatically wild type but mislocalized within cells and, for reasons that remain unclear, appears to disrupt the histone-to-protamine transition in drive-sensitive spermatids bearing many Rsp satellite repeats but not drive-insensitive spermatids bearing few or no Rsp satellite repeats. Evolutionary analyses show that the Sd-RanGAP duplication arose recently within the D. melanogaster lineage, exploiting the preexisting and considerably older Rsp satellite locus. Once established, the SD haplotype collected enhancers of distortion and suppressors of recombination. Further dissection of the molecular genetic and cellular basis of SD-mediated distortion seems likely to provide insights into several important areas currently understudied, including the genetic control of spermatogenesis, the maintenance and evolution of satellite DNAs, the possible roles of small interfering RNAs in the germline, and the molecular population genetics of the interaction of genetic linkage and natural selection.

Atomistic tight-binding computations of the structural and optical properties of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals

NASA Astrophysics Data System (ADS)

Sukkabot, Worasak

2018-05-01

A study of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals is carried out using atomistic tight-binding theory and the configuration interaction method to provide information for applications in bioimaging, biolabeling, display devices and near-infrared electronic instruments. The calculations yield the dependences of the internal and external passivated shells on the natural behaviours of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals. The reduction of the optical band gaps is observed with increasing numbers of monolayers in the external ZnS shell due to quantum confinement. Interestingly, the optical band gaps of CdTe/CdS/ZnS core/shell/shell nanocrystals are greater than those of CdTe/CdSe/ZnS core/shell/shell nanocrystals. In the presence of an external ZnS-coated shell, electron-hole wave function overlaps, oscillation strengths, ground-state exchange energies and Stokes shift are improved, whereas ground-state coulomb energies and fine-structure splitting are reduced. The oscillation strengths, Stokes shift and fine-structure splitting are reduced with the increase in external ZnS shell thickness. The oscillation strengths, Stokes shift and fine-structure splitting of CdTe/CdS/ZnS core/shell/shell nanocrystals are larger than those of CdTe/CdSe/ZnS core/shell/shell nanocrystals. Reduction of the atomistic electron-hole interactions is observed with increasing external ZnS shell size. The strong electron-hole interactions are more probed in CdTe/CdS/ZnS core/shell/shell nanocrystals than in CdTe/CdSe/ZnS core/shell/shell nanocrystals.

Production of recombinant proteins from Plasmodium falciparum in Escherichia coli.

PubMed

Guerra, Ángela Patricia; Calvo, Eliana Patricia; Wasserman, Moisés; Chaparro-Olaya, Jacqueline

2016-02-23

The production of recombinant proteins is essential for the characterization and functional study of proteins from Plasmodium falciparum. However, the proteins of P. falciparum are among the most challenging to express, and when expression is achieved, the recombinant proteins usually fold incorrectly and lead to the formation of inclusion bodies.  To obtain and purify four recombinant proteins and to use them as antigens to produce polyclonal antibodies. The production efficiency and solubility were evaluated as the proteins were expressed in two genetically modified strains of Escherichia coli to favor the production of heterologous proteins (BL21-CodonPlus (DE3)-RIL and BL21-pG-KJE8).  The four recombinant P. falciparum proteins corresponding to partial sequences of PfMyoA (Myosin A) and PfGAP50 (gliding associated protein 50), and the complete sequences of PfMTIP (myosin tail interacting protein) and PfGAP45 (gliding associated protein 45), were produced as glutathione S-transferase-fusion proteins, purified and used for immunizing mice.  The protein expression was much more efficient in BL21-CodonPlus, the strain that contains tRNAs that are rare in wild-type E. coli, compared to the expression in BL21-pG-KJE8. In spite of the fact that BL21-pG-KJE8 overexpresses chaperones, this strain did not minimize the formation of inclusion bodies.  The use of genetically modified strains of E. coli was essential to achieve high expression levels of the four evaluated P. falciparum proteins and lead to improved solubility of two of them. The approach used here allowed us to obtain and purify four P. falciparum proteins in enough quantity to produce polyclonal antibodies in mice, and a fair amount of two pure and soluble recombinant proteins for future assays.

Carbon-ionogel supercapacitors for integrated microelectronics.

PubMed

Leung, Greg; Smith, Leland; Lau, Jonathan; Dunn, Bruce; Chui, Chi On

2016-01-22

To exceed the performance limits of dielectric capacitors in microelectronic circuit applications, we design and demonstrate on-chip coplanar electric double-layer capacitors (EDLCs), or supercapacitors, employing carbon-coated gold electrodes with ionogel electrolyte. The formation of carbon-coated microelectrodes is accomplished by solution processing and results in a ten-fold increase in EDLC capacitance compared to bare gold electrodes without carbon. At frequencies up to 10 Hz, an areal capacitance of 2.1 pF μm(-2) is achieved for coplanar carbon-ionogel EDLCs with 10 μm electrode gaps and 0.14 mm(2) electrode area. Our smallest devices, comprised of 5 μm electrode gaps and 80 μm(2) of active electrode area, reach areal capacitance values of ∼0.3 pF μm(-2) at frequencies up to 1 kHz, even without carbon. To our knowledge, these are the highest reported values to date for on-chip EDLCs with sub-mm(2) areas. A physical EDLC model is developed through the use of computer-aided simulations for design exploration and optimization of coplanar EDLCs. Through modeling and comparison with experimental data, we highlight the importance of reducing the electrode gap and electrolyte resistance to achieve maximum performance from on-chip EDLCs.

Carbon-ionogel supercapacitors for integrated microelectronics

NASA Astrophysics Data System (ADS)

Leung, Greg; Smith, Leland; Lau, Jonathan; Dunn, Bruce; Chui, Chi On

2016-01-01

To exceed the performance limits of dielectric capacitors in microelectronic circuit applications, we design and demonstrate on-chip coplanar electric double-layer capacitors (EDLCs), or supercapacitors, employing carbon-coated gold electrodes with ionogel electrolyte. The formation of carbon-coated microelectrodes is accomplished by solution processing and results in a ten-fold increase in EDLC capacitance compared to bare gold electrodes without carbon. At frequencies up to 10 Hz, an areal capacitance of 2.1 pF μm-2 is achieved for coplanar carbon-ionogel EDLCs with 10 μm electrode gaps and 0.14 mm2 electrode area. Our smallest devices, comprised of 5 μm electrode gaps and 80 μm2 of active electrode area, reach areal capacitance values of ˜0.3 pF μm-2 at frequencies up to 1 kHz, even without carbon. To our knowledge, these are the highest reported values to date for on-chip EDLCs with sub-mm2 areas. A physical EDLC model is developed through the use of computer-aided simulations for design exploration and optimization of coplanar EDLCs. Through modeling and comparison with experimental data, we highlight the importance of reducing the electrode gap and electrolyte resistance to achieve maximum performance from on-chip EDLCs.

The effects of pleural fluid drainage on respiratory function in mechanically ventilated patients after cardiac surgery

PubMed Central

Brims, Fraser J H; Davies, Michael G; Elia, Andy; Griffiths, Mark J D

2015-01-01

Background Pleural effusions occur commonly after cardiac surgery and the effects of drainage on gas exchange in this population are not well established. We examined pulmonary function indices following drainage of pleural effusions in cardiac surgery patients. Methods We performed a retrospective study examining the effects of pleural fluid drainage on the lung function indices of patients recovering from cardiac surgery requiring mechanical ventilation for more than 7 days. We specifically analysed patients who had pleural fluid removed via an intercostal tube (ICT: drain group) compared with those of a control group (no effusion, no ICT). Results In the drain group, 52 ICTs were sited in 45 patients. The mean (SD) volume of fluid drained was 1180 (634) mL. Indices of oxygenation were significantly worse in the drain group compared with controls prior to drainage. The arterial oxygen tension (PaO2)/fractional inspired oxygen (FiO2) (P/F) ratio improved on day 1 after ICT placement (mean (SD), day 0: 31.01 (8.92) vs 37.18 (10.7); p<0.05) and both the P/F ratio and oxygenation index (OI: kPa/cm H2O=PaO2/mean airway pressure×FiO2) demonstrated sustained improvement to day 5 (P/F day 5: 39.85 (12.8); OI day 0: 2.88 (1.10) vs day 5: 4.06 (1.73); both p<0.01). The drain group patients were more likely to have an improved mode of ventilation on day 1 compared with controls (p=0.028). Conclusions Pleural effusion after cardiac surgery may impair oxygenation. Drainage of pleural fluid is associated with a rapid and sustained improvement in oxygenation. PMID:26339492

Relationship of the stretch-shortening cycle to sprint performance in trained female athletes.

PubMed

Hennessy, L; Kilty, J

2001-08-01

This study assessed the relationship of long and short stretch-shortening cycle test scores to sprint performances in trained female athletes. Seventeen trained, female, high school, competitive sprinters completed the following tests: countermovement jump for vertical distance (CMJ), bounce drop jump for height with minimum ground contact time (BDJ index), and ground contact time (GCT) during the BDJ and a 5-step bound (5B) test. Group mean and SD values were as follows: height, 167.7 +/- 3.7 cm; body mass, 59.9 +/- 7.2 kg; and percentage of body fat (PF), 20.3 +/- 1.8%. Sprint performances at 30-, 100-, and 300-m distances were assessed. Stretch-shortening cycle performance and sprint results (mean +/- SD) were as follows: CMJ, 33.8 +/- 3.8 cm; BDJ index, 166.7 +/- 24.7 cm/s; 5B test, 10.98 +/- 0.76 m; 30-m sprint, 4.58 +/- 0.17 seconds; 100-m sprint, 12.9 +/- 0.61 seconds; and 300-m sprint, 45.03 +/- 2.94 seconds. Correlations indicated that no relationship existed between PF and the dependent sprint variables. Significant correlations (p < 0.05) existed between CMJ and 30-m (r = -0.60), 100-m (r = -0.64), and 300-m (r = -0.55) sprint times; BDJ index and 30-m (r = -0.79) and 100-m (r = -0.75) sprint times; and 5B test and 300-m sprint time (r = -0.54). Multiple regression analysis found significant T values for BDJ index with 30- and 100-m sprints and CMJ and PF with 300 m. Results indicated that the BDJ index and CMJ tests were significantly related to sprint performances in female athletes.

Modeling of heat and mass transfer processes for the gap-lyophilization system using the mannitol-trehalose-NaCl formulation.

PubMed

Kuu, Wei Y; Doty, Mark J; Nisipeanu, Eugen; Rebbeck, Christine L; Cho, Yong K; Smit, Mark H

2014-09-01

Gap freezing (GF) is a new concept that was developed to reduce the primary drying time using an alternative freezing process. The purpose of this investigation was to determine the gap-tray heat transfer coefficient, Kgtr , and to investigate the effect of gap lyophilization on cycle reduction of a mannitol-trehalose-NaCl (MTN) formulation. The values of Kgtr were measured using the product temperature profiles in three different configurations: (1) shelf freezing followed by shelf drying (denoted as SF-SD), (2) GF followed by SD (denoted as GF-SD), and (3) GF followed by gap drying (denoted as GF-GD). For the lyophilization cycle using shelf drying (SF-SD), 80% of the heat transferred during primary drying was from the bottom shelf to the vial, versus 20% via radiation from the top shelf. For the lyophilization cycle using gap drying (GF-GD), only 37% of the heat transferred during primary drying was from the bottom shelf to the vial versus 63% via radiation from the top shelf. Furthermore, GF in conjunction with annealing significantly reduces the dry layer resistance of the MTN formulation, which is the opposite of what was observed with a conventional freezing cycle. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

1999 Leak Detection and Monitoring and Mitigation Strategy Update

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

OHL, P.C.

This document is a complete revision of WHC-SD-WM-ES-378, Rev 1. This update includes recent developments in Leak Detection, Leak Monitoring, and Leak Mitigation technologies, as well as, recent developments in single-shell tank retrieval technologies. In addition, a single-shell tank retrieval release protection strategy is presented.

A nucleon-pair and boson coexistent description of nuclei

NASA Astrophysics Data System (ADS)

Dai, Lianrong; Pan, Feng; Draayer, J. P.

2017-07-01

We study a mixture of s-bosons and like-nucleon pairs with the standard pairing interaction outside an inert core. Competition between the nucleon-pairs and s-bosons is investigated in this scenario. The robustness of the BCS-BEC coexistence and crossover phenomena are examined through an analysis of pf-shell nuclei with realistic single-particle energies, in which two configurations with Pauli blocking of nucleon-pair orbits due to the formation of the s-bosons is taken into account. When the nucleon-pair orbits are considered to be independent of the s-bosons, the BCS-BEC crossover becomes smooth, with the number of the s-bosons noticeably more than that of the nucleon-pairs near the half-shell point, a feature that is demonstrated in the pf-shell for several values of the standard pairing interaction strength. As a further test of the robustness of the BCS-BEC coexistence and crossover phenomena in nuclei, results are given for values of even-even 102-130Sn with 100Sn taken as a core and valence neutron pairs confined within the 1d 5/2, 0g 7/2, 1d 3/2, 2s 1/2, 1h 11/2 orbits in the nucleon-pair orbit and the s-boson independent approximation. The results indicate that the B(E2) values are reproduced well. Supported by National Natural Science Foundation of China (11375080, 11675071), the U.S. National Science Foundation (OCI-0904874 and ACI-1516338), U. S. Department of Energy (DE-SC0005248), the Southeastern Universities Research Association, the China-U. S. Theory Institute for Physics with Exotic Nuclei (CUSTIPEN) (DE-SC0009971), and the LSU-LNNU joint research program (9961) is acknowledged

PF2fit: Polar Fast Fourier Matched Alignment of Atomistic Structures with 3D Electron Microscopy Maps.

PubMed

Bettadapura, Radhakrishna; Rasheed, Muhibur; Vollrath, Antje; Bajaj, Chandrajit

2015-10-01

There continue to be increasing occurrences of both atomistic structure models in the PDB (possibly reconstructed from X-ray diffraction or NMR data), and 3D reconstructed cryo-electron microscopy (3D EM) maps (albeit at coarser resolution) of the same or homologous molecule or molecular assembly, deposited in the EMDB. To obtain the best possible structural model of the molecule at the best achievable resolution, and without any missing gaps, one typically aligns (match and fits) the atomistic structure model with the 3D EM map. We discuss a new algorithm and generalized framework, named PF(2) fit (Polar Fast Fourier Fitting) for the best possible structural alignment of atomistic structures with 3D EM. While PF(2) fit enables only a rigid, six dimensional (6D) alignment method, it augments prior work on 6D X-ray structure and 3D EM alignment in multiple ways: Scoring. PF(2) fit includes a new scoring scheme that, in addition to rewarding overlaps between the volumes occupied by the atomistic structure and 3D EM map, rewards overlaps between the volumes complementary to them. We quantitatively demonstrate how this new complementary scoring scheme improves upon existing approaches. PF(2) fit also includes two scoring functions, the non-uniform exterior penalty and the skeleton-secondary structure score, and implements the scattering potential score as an alternative to traditional Gaussian blurring. Search. PF(2) fit utilizes a fast polar Fourier search scheme, whose main advantage is the ability to search over uniformly and adaptively sampled subsets of the space of rigid-body motions. PF(2) fit also implements a new reranking search and scoring methodology that considerably improves alignment metrics in results obtained from the initial search.

PF2 fit: Polar Fast Fourier Matched Alignment of Atomistic Structures with 3D Electron Microscopy Maps

PubMed Central

Bettadapura, Radhakrishna; Rasheed, Muhibur; Vollrath, Antje; Bajaj, Chandrajit

2015-01-01

There continue to be increasing occurrences of both atomistic structure models in the PDB (possibly reconstructed from X-ray diffraction or NMR data), and 3D reconstructed cryo-electron microscopy (3D EM) maps (albeit at coarser resolution) of the same or homologous molecule or molecular assembly, deposited in the EMDB. To obtain the best possible structural model of the molecule at the best achievable resolution, and without any missing gaps, one typically aligns (match and fits) the atomistic structure model with the 3D EM map. We discuss a new algorithm and generalized framework, named PF2 fit (Polar Fast Fourier Fitting) for the best possible structural alignment of atomistic structures with 3D EM. While PF2 fit enables only a rigid, six dimensional (6D) alignment method, it augments prior work on 6D X-ray structure and 3D EM alignment in multiple ways: Scoring. PF2 fit includes a new scoring scheme that, in addition to rewarding overlaps between the volumes occupied by the atomistic structure and 3D EM map, rewards overlaps between the volumes complementary to them. We quantitatively demonstrate how this new complementary scoring scheme improves upon existing approaches. PF2 fit also includes two scoring functions, the non-uniform exterior penalty and the skeleton-secondary structure score, and implements the scattering potential score as an alternative to traditional Gaussian blurring. Search. PF2 fit utilizes a fast polar Fourier search scheme, whose main advantage is the ability to search over uniformly and adaptively sampled subsets of the space of rigid-body motions. PF2 fit also implements a new reranking search and scoring methodology that considerably improves alignment metrics in results obtained from the initial search. PMID:26469938

Effects of Resection of Posterior Condyles of Femur on Extension Gap of Knee Joint in Total Knee Arthroplasty.

PubMed

Seo, Seung-Suk; Kim, Chang-Wan; Seo, Jin-Hyuk; Kim, Do-Hun; Kim, Ok-Gul; Lee, Chang-Rack

2017-06-01

When evaluating the effects of the preparation of the flexion gap on the extension gap in total knee arthroplasty (TKA), the effects of posterior condylar resection and osteophyte removal on the extension gap should be differentiated. Although the amount of osteophytes differs between patients, posterior condylar resection is a procedure that is routinely implemented in TKA. The aim of this study was to assess the effects of the resection of the posterior condyle of the femur on the extension gap in posterior-stabilized (PS) TKA. We enrolled 40 knees that underwent PS TKA between July 2010 and February 2011 with no or minimal osteophytes in the posterior compartment and a varus deformity of <15°. We measured the extension gap before and after the resection of the posterior condyle of the femur using a tensor under 20 and 40 lb of distraction force. Under 20 lb of distraction force, the average extension gap was 13.3 mm (standard deviation [SD], 1.6) before and 13.8 mm (SD, 1.6) after posterior condylar resection. Under 40 lb of distraction force, the average extension gap was 15.1 mm (SD, 1.5) before and 16.1 mm (SD, 1.7) after posterior condylar resection. The resection of the posterior condyle of the femur in PS TKA increased the extension gap. However, this increase was only by approximately 1 mm. In conclusion, posterior condylar resection does increase the extension gap by approximately 1 mm. However, in most case, this change in unlikely to be clinically important. Copyright © 2017 Elsevier Inc. All rights reserved.

The PROMIS Physical Function item bank was calibrated to a standardized metric and shown to improve measurement efficiency.

PubMed

Rose, Matthias; Bjorner, Jakob B; Gandek, Barbara; Bruce, Bonnie; Fries, James F; Ware, John E

2014-05-01

To document the development and psychometric evaluation of the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) item bank and static instruments. The items were evaluated using qualitative and quantitative methods. A total of 16,065 adults answered item subsets (n>2,200/item) on the Internet, with oversampling of the chronically ill. Classical test and item response theory methods were used to evaluate 149 PROMIS PF items plus 10 Short Form-36 and 20 Health Assessment Questionnaire-Disability Index items. A graded response model was used to estimate item parameters, which were normed to a mean of 50 (standard deviation [SD]=10) in a US general population sample. The final bank consists of 124 PROMIS items covering upper, central, and lower extremity functions and instrumental activities of daily living. In simulations, a 10-item computerized adaptive test (CAT) eliminated floor and decreased ceiling effects, achieving higher measurement precision than any comparable length static tool across four SDs of the measurement range. Improved psychometric properties were transferred to the CAT's superior ability to identify differences between age and disease groups. The item bank provides a common metric and can improve the measurement of PF by facilitating the standardization of patient-reported outcome measures and implementation of CATs for more efficient PF assessments over a larger range. Copyright © 2014. Published by Elsevier Inc.

Sound transmission through double cylindrical shells lined with porous material under turbulent boundary layer excitation

NASA Astrophysics Data System (ADS)

Zhou, Jie; Bhaskar, Atul; Zhang, Xin

2015-11-01

This paper investigates sound transmission through double-walled cylindrical shell lined with poroelastic material in the core, excited by pressure fluctuations due to the exterior turbulent boundary layer (TBL). Biot's model is used to describe the sound wave propagating in the porous material. Three types of constructions, bonded-bonded, bonded-unbonded and unbonded-unbonded, are considered in this study. The power spectral density (PSD) of the inner shell kinetic energy is predicted for two turbulent boundary layer models, different air gap depths and three types of polyimide foams, respectively. The peaks of the inner shell kinetic energy due to shell resonance, hydrodynamic coincidence and acoustic coincidence are discussed. The results show that if the frequency band over the ring frequency is of interest, an air gap, even if very thin, should exist between the two elastic shells for better sound insulation. And if small density foam has a high flow resistance, a superior sound insulation can still be maintained.

Gamma ray heating and neutrino cooling rates due to weak interaction processes on sd-shell nuclei in stellar cores

NASA Astrophysics Data System (ADS)

Fayaz, Muhammad; Nabi, Jameel-Un; Majid, Muhammad

2017-07-01

Gamma ray heating and neutrino cooling rates, due to weak interaction processes, on sd-shell nuclei in stellar core are calculated using the proton neutron quasiparticle random phase approximation theory. The recent extensive experimental mass compilation of Wang et al. (Chin. Phys. C 36:1603, 2012), other improved model input parameters including nuclear quadrupole deformation (Raman et al. in At. Data Nucl. Data Tables 78(1):1-128, 2001; Möller et al. in At. Data Nucl. Data Tables 109:1-204, 2016) and physical constants are taken into account in the current calculation. The purpose of this work is two fold, one is to improve the earlier calculation of weak rates performed by Nabi and Klapdor-Kleingrothaus (At. Data Nucl. Data Tables 71:149, 1999a) using the same theory. We further compare our results with previous calculations. The selected sd-shell nuclei, considered in this work, are of special interest for the evolution of O-Ne-Mg core in 8-10 M_{⊙} stars due to competitive gamma ray heating rates and cooling by URCA processes. The outcome of these competitions is to determine, whether the stars end up as a white dwarf (Nabi in Phys. Rev. C 78(4):045801, 2008b), an electron-capture supernova (Jones et al. in Astrophys. J. 772(2):150, 2013) or Fe core-collapse supernova (Suzuki et al. in Astrophys. J. 817(2):163, 2016). The selected sd-shell nuclei for calculation of associated weak-interaction rates include ^{20,23}O, ^{20,23}F, ^{20,23,24}Ne, {}^{20,23-25}Na, and {}^{23-25}Mg. The cooling and heating rates are calculated for density range (10 ≤ ρ (g cm^{-3}) ≤ 10^{11}) and temperature range (0.01× 109≤ T(K)≤ 30× 109). The calculated gamma heating rates are orders of magnitude bigger than the shell model rates (except for ^{25}Mg at low densities). At high temperatures the gamma heating rates are in reasonable agreement. The calculated cooling rates are up to an order of magnitude bigger for odd-A nuclei.

Vocal fundamental and formant frequencies affect perceptions of speaker cooperativeness.

PubMed

Knowles, Kristen K; Little, Anthony C

2016-01-01

In recent years, the perception of social traits in faces and voices has received much attention. Facial and vocal masculinity are linked to perceptions of trustworthiness; however, while feminine faces are generally considered to be trustworthy, vocal trustworthiness is associated with masculinized vocal features. Vocal traits such as pitch and formants have previously been associated with perceived social traits such as trustworthiness and dominance, but the link between these measurements and perceptions of cooperativeness have yet to be examined. In Experiment 1, cooperativeness ratings of male and female voices were examined against four vocal measurements: fundamental frequency (F0), pitch variation (F0-SD), formant dispersion (Df), and formant position (Pf). Feminine pitch traits (F0 and F0-SD) and masculine formant traits (Df and Pf) were associated with higher cooperativeness ratings. In Experiment 2, manipulated voices with feminized F0 were found to be more cooperative than voices with masculinized F0(,) among both male and female speakers, confirming our results from Experiment 1. Feminine pitch qualities may indicate an individual who is friendly and non-threatening, while masculine formant qualities may reflect an individual that is socially dominant or prestigious, and the perception of these associated traits may influence the perceived cooperativeness of the speakers.

Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First-Principles and Classical Reactive Molecular Dynamics

DOE PAGES

Ong, Mitchell T.; Verners, Osvalds; Draeger, Erik W.; ...

2014-12-19

We report that lithium-ion battery performance is strongly influenced by the ionic conductivity of the electrolyte, which depends on the speed at which Li ions migrate across the cell and relates to their solvation structure. The choice of solvent can greatly impact both the solvation and diffusivity of Li ions. In this work, we used first-principles molecular dynamics to examine the solvation and diffusion of Li ions in the bulk organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC), and a mixture of EC and EMC. We found that Li ions are solvated by either carbonyl or ether oxygen atoms of the solvents and sometimes by the PF more » $$\\bar{6}$$ anion. Li + prefers a tetrahedrally coordinated first solvation shell regardless of which species are involved, with the specific preferred solvation structure dependent on the organic solvent. In addition, we calculated Li diffusion coefficients in each electrolyte, finding slightly larger diffusivities in the linear carbonate EMC compared to the cyclic carbonate EC. The magnitude of the diffusion coefficient correlates with the strength of Li + solvation. Corresponding analysis for the PF $$\\bar{6}$$ anion shows greater diffusivity associated with a weakly bound, poorly defined first solvation shell. In conclusion, these results can be used to aid in the design of new electrolytes to improve Li-ion battery performance.« less

Isospin Symmetry Along The N=Z Line In The sd Shell

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

Della Vedova, F.; Lenzi, S. M.; Farnea, E.

2005-04-05

Excited states have been studied in sd-shell nuclei following the 16O (70 MeV) + 24Mg (400 {mu}g/cm2) fusion-evaporation reaction. The GASP spectrometer in conjunction with the charged-particle detector ISIS and the Neutron ring allowed the detection of the {gamma}-rays in coincidence with evaporated light particles. New data on the mirror pairs A=31 and A=35 have been obtained. In particular, the comparison between the level schemes of 35Ar and 35Cl has confirmed the importance of the electromagnetic spin-orbit term, which explains the large Mirror Energy Difference values. Evidence of isospin mixing can be deduced from the E1 transitions.

Larger sized wire arrays on 1.5 MA Z-pinch generator

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

Safronova, A. S., E-mail: alla@unr.edu; Kantsyrev, V. L., E-mail: alla@unr.edu; Weller, M. E., E-mail: alla@unr.edu

Experiments on the UNR Zebra generator with Load Current Multiplier (LCM) allow for implosions of larger sized wire array loads than at standard current of 1 MA. Advantages of larger sized planar wire array implosions include enhanced energy coupling to plasmas, better diagnostic access to observable plasma regions, and more complex geometries of the wire loads. The experiments with larger sized wire arrays were performed on 1.5 MA Zebra with LCM (the anode-cathode gap was 1 cm, which is half the gap used in the standard mode). In particular, larger sized multi-planar wire arrays had two outer wire planes frommore » mid-atomic-number wires to create a global magnetic field (gmf) and plasma flow between them. A modified central plane with a few Al wires at the edges was put in the middle between outer planes to influence gmf and to create Al plasma flow in the perpendicular direction (to the outer arrays plasma flow). Such modified plane has different number of empty slots: it was increased from 6 up to 10, hence increasing the gap inside the middle plane from 4.9 to 7.7 mm, respectively. Such load configuration allows for more independent study of the flows of L-shell mid-atomic-number plasma (between the outer planes) and K-shell Al plasma (which first fills the gap between the edge wires along the middle plane) and their radiation in space and time. We demonstrate that such configuration produces higher linear radiation yield and electron temperatures as well as advantages of better diagnostics access to observable plasma regions and how the load geometry (size of the gap in the middle plane) influences K-shell Al radiation. In particular, K-shell Al radiation was delayed compared to L-shell mid-atomic-number radiation when the gap in the middle plane was large enough (when the number of empty slots was increased up to ten)« less

One-dimensional carrier confinement in “Giant” CdS/CdSe excitonic nanoshells

DOE PAGES

Razgoniaeva, Natalia; Moroz, Pavel; Yang, Mingrui; ...

2017-05-23

Here, the emerging generation of quantum dot optoelectronic devices offers an appealing prospect of a size-tunable band gap. The confinement-enabled control over electronic properties, however, requires nanoparticles to be sufficiently small, which leads to a large area of interparticle boundaries in a film. Such interfaces lead to a high density of surface traps which ultimately increase the electrical resistance of a solid. To address this issue, we have developed an inverse energy-gradient core/shell architecture supporting the quantum confinement in nanoparticles larger than the exciton Bohr radius. The assembly of such nanostructures exhibits a relatively low surface-to-volume ratio, which was manifestedmore » in this work through the enhanced conductance of solution-processed films. The reported core/shell geometry was realized by growing a narrow gap semiconductor layer (CdSe) on the surface of a wide-gap core material (CdS) promoting the localization of excitons in the shell domain, as was confirmed by ultrafast transient absorption and emission lifetime measurements. The band gap emission of fabricated nanoshells, ranging from 15 to 30 nm in diameter, has revealed a characteristic size-dependent behavior tunable via the shell thickness with associated quantum yields in the 4.4–16.0% range.« less

One-dimensional carrier confinement in “Giant” CdS/CdSe excitonic nanoshells

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

Razgoniaeva, Natalia; Moroz, Pavel; Yang, Mingrui

Here, the emerging generation of quantum dot optoelectronic devices offers an appealing prospect of a size-tunable band gap. The confinement-enabled control over electronic properties, however, requires nanoparticles to be sufficiently small, which leads to a large area of interparticle boundaries in a film. Such interfaces lead to a high density of surface traps which ultimately increase the electrical resistance of a solid. To address this issue, we have developed an inverse energy-gradient core/shell architecture supporting the quantum confinement in nanoparticles larger than the exciton Bohr radius. The assembly of such nanostructures exhibits a relatively low surface-to-volume ratio, which was manifestedmore » in this work through the enhanced conductance of solution-processed films. The reported core/shell geometry was realized by growing a narrow gap semiconductor layer (CdSe) on the surface of a wide-gap core material (CdS) promoting the localization of excitons in the shell domain, as was confirmed by ultrafast transient absorption and emission lifetime measurements. The band gap emission of fabricated nanoshells, ranging from 15 to 30 nm in diameter, has revealed a characteristic size-dependent behavior tunable via the shell thickness with associated quantum yields in the 4.4–16.0% range.« less

Core–shell interaction and its impact on the optical absorption of pure and doped core-shell CdSe/ZnSe nanoclusters

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

Wang, Xinqin; Cui, Yingqi; Zeng, Qun

The structural, electronic, and optical properties of core-shell nanoclusters, (CdSe){sub x}@(CdSe){sub y} and their Zn-substituted complexes of x = 2–4 and y = 16–28, were studied with density functional theory calculations. The substitution was applied in the cores, the shells, and/or the whole clusters. All these clusters are characterized by their core-shell structures in which the core-shell interaction was found different from those in core or in shell, as reflected by their bondlengths, volumes, and binding energies. Moreover, the core and shell combine together to compose a new cluster with electronic and optical properties different from those of separated individuals,more » as reflected by their HOMO-LUMO gaps and optical absorptions. With the substitution of Cd by Zn, the structural, electronic, and optical properties of clusters change regularly. The binding energy increases with Zn content, attributed to the strong Zn–Se bonding. For the same core/shell, the structure with a CdSe shell/core has a narrower gap than that with a ZnSe shell/core. The optical absorption spectra also change accordingly with Zn substitution. The peaks blueshift with increasing Zn concentration, accompanying with shape variations in case large number of Cd atoms are substituted. Our calculations reveal the core-shell interaction and its influence on the electronic and optical properties of the core-shell clusters, suggesting a composition–structure–property relationship for the design of core-shell CdSe and ZnSe nanoclusters.« less

Planktonic Foraminifera Proxies Calibration Off the NW Iberian Margin: Nutrients Approach

NASA Astrophysics Data System (ADS)

Salgueiro, E.; Castro, C. G.; Zuniga, D.; Martin, P. A.; Groeneveld, J.; de la Granda, F.; Villaceiros-Robineau, N.; Alonso-Perez, F.; Alberto, A.; Rodrigues, T.; Rufino, M. M.; Abrantes, F. F. G.; Voelker, A. H. L.

2014-12-01

Planktonic foraminifera (PF) shells preserved in marine sediments are a useful tool to reconstruct productivity conditions at different geological timescales. However, the accuracy of these paleoreconstructions depends on the data set and calibration quality. Several calibration works have been defining and improving the use of proxies for productivity and nutrient cycling parameters. Our contribution is centred on a multi-proxy calibration at a regional coastal upwelling system. To minimize the existing uncertainties affecting the use of trace elements and C stable isotopes as productivity proxy in the high productivity upwelling areas, we investigate the content and distribution of Ba/Ca and δ13C in the water column, its transference into the planktonic foraminifera shells, and, how the living planktonic foraminifera Ba/Ca and δ13C signal is related to the same planktonic foraminiferal species preserved in the sediment record. This study is based on a large data set from two stations (RAIA - 75m water depth, and CALIBERIA - 350m water depth) located off the NW Iberian margin (41.5-42.5ºN; 9-10ºW), and includes: i) two year monthly water column data (temperature, salinity, nutrients, chlorophyll a, Ba/Ca, and δ13C-DIC); ii) seasonal Ba/Ca, δ13C in several living PF species at both stations; and iii) Ba/Ca and δ13C in several PF species from a large set of core-top sediment samples in the study region. Additionally, total organic carbon and total alkenones were also measured in the sediment. Our results showed the link between productivity proxies in the surface sediment foraminifera assemblage and the processes regulating the actual phytoplankton dynamics in an upwelling area. The understanding of this relationship has special relevance since it gives fundamental information related to the past oceanic biogeochemistry and/or climate and improves the prevision of future changes against possible climate variability due to anthropogenic forcing.

Piezo-phototronic Effect Enhanced UV/Visible Photodetector Based on Fully Wide Band Gap Type-II ZnO/ZnS Core/Shell Nanowire Array.

PubMed

Rai, Satish C; Wang, Kai; Ding, Yong; Marmon, Jason K; Bhatt, Manish; Zhang, Yong; Zhou, Weilie; Wang, Zhong Lin

2015-06-23

A high-performance broad band UV/visible photodetector has been successfully fabricated on a fully wide bandgap ZnO/ZnS type-II heterojunction core/shell nanowire array. The device can detect photons with energies significantly smaller (2.2 eV) than the band gap of ZnO (3.2 eV) and ZnS (3.7 eV), which is mainly attributed to spatially indirect type-II transition facilitated by the abrupt interface between the ZnO core and ZnS shell. The performance of the device was further enhanced through the piezo-phototronic effect induced lowering of the barrier height to allow charge carrier transport across the ZnO/ZnS interface, resulting in three orders of relative responsivity change measured at three different excitation wavelengths (385, 465, and 520 nm). This work demonstrates a prototype UV/visible photodetector based on the truly wide band gap semiconducting 3D core/shell nanowire array with enhanced performance through the piezo-phototronic effect.

Nuclear tetrahedral symmetry: possibly present throughout the periodic table.

PubMed

Dudek, J; Goźdź, A; Schunck, N; Miśkiewicz, M

2002-06-24

More than half a century after the fundamental, spherical shell structure in nuclei had been established, theoretical predictions indicated that the shell gaps comparable or even stronger than those at spherical shapes may exist. Group-theoretical analysis supported by realistic mean-field calculations indicate that the corresponding nuclei are characterized by the TD(d) ("double-tetrahedral") symmetry group. Strong shell-gap structure is enhanced by the existence of the four-dimensional irreducible representations of TD(d); it can be seen as a geometrical effect that does not depend on a particular realization of the mean field. Possibilities of discovering the TD(d) symmetry in experiment are discussed.

Polarization effects on spectra of spherical core/shell nanostructures: Perturbation theory against finite difference approach

NASA Astrophysics Data System (ADS)

Ibral, Asmaa; Zouitine, Asmaa; Assaid, El Mahdi; El Achouby, Hicham; Feddi, El Mustapha; Dujardin, Francis

2015-02-01

Poisson equation is solved analytically in the case of a point charge placed anywhere in a spherical core/shell nanostructure, immersed in aqueous or organic solution or embedded in semiconducting or insulating matrix. Conduction and valence band-edge alignments between core and shell are described by finite height barriers. Influence of polarization charges induced at the surfaces where two adjacent materials meet is taken into account. Original expressions of electrostatic potential created everywhere in the space by a source point charge are derived. Expressions of self-polarization potential describing the interaction of a point charge with its own image-charge are deduced. Contributions of double dielectric constant mismatch to electron and hole ground state energies as well as nanostructure effective gap are calculated via first order perturbation theory and also by finite difference approach. Dependencies of electron, hole and gap energies against core to shell radii ratio are determined in the case of ZnS/CdSe core/shell nanostructure immersed in water or in toluene. It appears that finite difference approach is more efficient than first order perturbation method and that the effect of polarization charge may in no case be neglected as its contribution can reach a significant proportion of the value of nanostructure gap.

Improving the In-Medium Similarity Renormalization Group via approximate inclusion of three-body effects

NASA Astrophysics Data System (ADS)

Morris, Titus; Bogner, Scott

2016-09-01

The In-Medium Similarity Renormalization Group (IM-SRG) has been applied successfully to the ground state of closed shell finite nuclei. Recent work has extended its ability to target excited states of these closed shell systems via equation of motion methods, and also complete spectra of the whole SD shell via effective shell model interactions. A recent alternative method for solving of the IM-SRG equations, based on the Magnus expansion, not only provides a computationally feasible route to producing observables, but also allows for approximate handling of induced three-body forces. Promising results for several systems, including finite nuclei, will be presented and discussed.

Radii in the sd shell and the 1s 1/2 “halo” orbit: A game changer

NASA Astrophysics Data System (ADS)

Bonnard, J.; Zuker, A. P.

2018-05-01

A new microscopic parametrisation of nuclear radii as a functional of single-particle occupation numbers is presented. Its form is inspired by the Duflo-Zuker phenomenological fit which contains a “correlation” term that recently made it possible to understand the isotope shifts of several species as due to unexpectedly large 1s 1/2 and 1p orbits [Bonnard J, Lenzi S M and Zuker A P 2016 Phys. Rev. Lett. 116 212501]. It will be shown that the calculated radii for sd-shell nuclei reproduce the experimental data better than the most accurate existing fits. These results reveal a very peculiar behaviour of the 1s 1/2 orbit: It is huge (about 1.6 fm bigger than its d counterparts of about 3.5 fm) up to N, Z = 14, then drops abruptly but remains some 0.6 fm larger than the d orbits. An intriguing mechanism bound to challenge our understanding of shell formation.

Projection of angular momentum via linear algebra

DOE PAGES

Johnson, Calvin W.; O'Mara, Kevin D.

2017-12-01

Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. Here, we show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications tomore » $$^{48}$$Cr and $$^{60}$$Fe in the $pf$ shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.« less

Projection of angular momentum via linear algebra

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

Johnson, Calvin W.; O'Mara, Kevin D.

Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. Here, we show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications tomore » $$^{48}$$Cr and $$^{60}$$Fe in the $pf$ shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.« less

[Project financing in public hospital trusts].

PubMed

Contarino, F; Grosso, G; Mistretta, A

2009-01-01

The growing debate in recent years over how to finance public works through private capital has progressively highlighted the role of project finance (PF) and publicprivate partnerships (PPP) in general. More and more European countries are turning to PF to finance their public infrastructure development. The UK, which pioneered the adoption of project finance in this field, has been followed by Italy, Spain, France, Portugal and Germany and more recently by Greece, Czech Republic and Poland. Beginning in the late 1990's, Italy has steadily amplified its use of PF and PPPs in key sectors such as healthcare as an alternative way of funding the modernisation of its health facilities and hospitals. The trend reveal an average annual growth of 10.9% since 2002 with peaks of varying intensity over the five year period. Project finance and PPPs represent an effective response to the country's infrastructure gap and support the competitiveness of local systems and the quality of public services. None of this will transpire, however without energetic new planning efforts and adequate policy at the centre.

Li + solvation and kinetics of Li +–BF 4 -/PF 6 - ion pairs in ethylene carbonate. A molecular dynamics study with classical rate theories

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

Chang, Tsun-Mei; Dang, Liem X.

Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ethylene carbonate (EC) exchange process between the first and second solvation shells around Li+ and the dissociation kinetics of ion pairs Li+-[BF4] and Li+-[PF6] in this solvent. We calculate the exchange rates using transition state theory and correct them with transmission coefficients computed by the reactive flux; Impey, Madden, and McDonald approaches; and Grote-Hynes theory. We found the residence times of EC around Li+ ions varied from 70 to 450 ps, depending on the correction method used. We found the relaxation times changed significantlymore » from Li+-[BF4] to Li+-[PF6] ion pairs in EC. Our results also show that, in addition to affecting the free energy of dissociation in EC, the anion type also significantly influence the dissociation kinetics of ion pairing. This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. The calculations were carried out using computer resources provided by the Office of Basic Energy Sciences.« less

Protein-Induced Fluorescence Enhancement Based Detection of Plasmodium falciparum Glutamate Dehydrogenase Using Carbon Dot Coupled Specific Aptamer.

PubMed

Singh, Naveen Kumar; Chakma, Babina; Jain, Priyamvada; Goswami, Pranab

2018-06-11

A novel 90-mer long ssDNA aptamer (NG3) covering a 40-mer random region targeting Plasmodium falciparum glutamate dehydrogenase ( PfGDH) developed through systematic evolution of ligands by exponential enrichment (SELEX) technique. The binding affinity of the aptamer to PfGDH discerned by circular dichroism (CD) was 0.5 ± 0.04 μM. The specificity of the aptamer toward the target was confirmed by gel electrophoresis and CD studies. The presence of two quadruplex forming regions, two big and four small stem loop structures with a δG of -7.99 kcal mol -1 for NG3 were deduced by computational studies. The spherical carbon dots (Cdots) of size 2-4 nm, synthesized by pyrolysis method using l-glutamate as a substrate were covalently linked to the amine modified aptamer. The Cdot with a band gap of 2.8 eV and a quantum yield of 34% produced fluorescence at ∼ λ 410 nm when excited at λ 320nm . The quantum yield of Cdot-aptamer assembly was increased up to 40% in the presence of the PfGDH in solution. A linear relationship with a dynamic range of 0.5 nM to 25 nM (R 2 = 0.98) and a limit of detection (LOD) of 0.48 nM was observed between the fluorescence intensity of the Cdots-aptamer conjugate and the concentration of PfGDH. The method could detect PfGDH with an LOD of 2.85 nM in diluted serum sample. This novel simple, sensitive and specific protein induced fluorescence enhancement based detection of PfGDH has a great potential to develop as a method for malaria detection.

Elucidating photophysical attributes of alpha,alpha'-diimine ligands, rhodium(III) dicyano-bis (alpha,alpha'-diimine) and tris(alpha,alpha'-diimine) complexes via ab inition and density-functional calculations

NASA Astrophysics Data System (ADS)

Matz, Phillip Daniel

Based on crystal structure data, the recently developed density functional PBE1PBE predicts ground state equilibrium geometries in good agreement with experiments. Bond length and angle alpha,alpha'-diimine ligand Mean Absolute Deviation (MAD) values of 0.0077 A and 0.63° are obtained with the low-cost model chemistry PBE1PBE/6-21G. Theoretical trends, specifically the gs → 1pipi* absorption energies and 3pipi* → gs phosphorescence emission energies of the ligands also agree well with experiment. Computations on [Ru(II)(1,10-phenanthroline)3]2+ indicate that the Stuttgart ECP ECP28MWB is capable of reproducing adequately the geometries and photophysical characteristics of transition-metal complexes when paired with the DFT hybrid functional PBE1PBE and the Pople-style split-valence 6-21G basis set describing the ligands. Examination shows that the predicted photophysical properties of both [Rh(III)(s-NN)3](PF6) 3 and [Rh(III)(CN)2(s-NN)2](PF6) complexes agree with experimental evidence in many, but not all aspects. The experimentally observed spectroscopic trend for the gs → 1pipi* absorption energies is reproduced, namely the absorption bands of phenanthroline complexes containing progressively more methyl substituents are monotonically red-shifted relative to the parent phenanthroline in the following energy order: phen > 4-Mephen > 4,7-Me2phen > 3,4,7,8-Me4phen >> 5,6-Me 2phen. Also, the trend of the experimental 3pipi* → gs phosphorescence emission energies is reproduced by the calculations. Experimentally, the activation barriers for the onset of photochemistry in glycerol matrices are reported to be around 2500 cm-1 and 2000 cm-1 for the [Rh(III)(s-NN)3](PF 6)3 and [Rh(III)(CN)2(s-NN)2](PF 6) complexes, respectively. Calculations of the energy gap between the lowest 3pipi* states and the ligand-field states locate the ligand-field states ˜5000cm-1 above the 3pipi* manifolds in the [Rh(III)(s-NN)3](PF6) 3 complexes, far exceeding the experimentally observed values. Analogous calculations on [Rh(III)(CN)2(s-NN)2](PF6) complexes predict an energy gap closer to the experimentally observed activation barriers (˜2500 cm-1) and correctly reproduce the observed trend of increasing activation energy with increasing methyl-substitution, but the ligand field states are shown to possess substantial ligand-centered character.

Note: A portable pulsed neutron source based on the smallest sealed-type plasma focus device.

PubMed

Niranjan, Ram; Rout, R K; Mishra, Prabhat; Srivastava, Rohit; Rawool, A M; Kaushik, T C; Gupta, Satish C

2011-02-01

Development and operation of a portable and compact pulsed neutron source based on sealed-type plasma focus (PF) device are reported. The unit is the smallest sealed-type neutron producing PF device. The effective volume of the PF unit is 33 cm(3) only. A compact size single capacitor (4 μF) is used as the energy driver. A battery based power supply unit is used for charging the capacitor and triggering the spark gap. The PF unit is operated at 10 kV (200 J) and at a deuterium gas filling pressure of 8 mb. The device is operated over a time span of 200 days and the neutron emissions have been observed for 200 shots without changing the gas in between the shots. The maximum yield of this device is 7.8 × 10(4) neutrons/pulse. Beyond 200 shots the yield is below the threshold (1050 neutrons/pulse) of our (3)He detector. The neutron energy is evaluated using time of flight technique and the value is (2.49 ± 0.27) MeV. The measured neutron pulse width is (24 ± 5) ns. Multishot and long duration operations envisage the potentiality of such portable device for repetitive mode of operation.

Paeoniflorin improves cardiac function and decreases adverse postinfarction left ventricular remodeling in a rat model of acute myocardial infarction.

PubMed

Chen, Hengwen; Dong, Yan; He, Xuanhui; Li, Jun; Wang, Jie

2018-01-01

Paeoniflorin (PF) is the active component of Paeonia lactiflora Pall. or Paeonia veitchii Lynch. This study was, therefore, aimed to evaluate the improvement and mechanism of the PF on ventricular remodeling in rats with acute myocardial infarction (AMI). In this study, AMI model was established by ligating the anterior descending coronary artery in Wistar rats. After 4 weeks gavage of PF, the apparent signs and the left ventricle weight index of Wistar rats were observed. The left ventricular ejection fraction (LVEF) was evaluated by Doppler ultrasonography. Changes in cardiac morphology were observed by pathologic examination, and apoptosis was observed by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, enzyme-linked immunosorbent assay was used to detect the expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) interleukin-10 (IL-10) and brain natriuretic peptide (BNP). Immunohistochemistry and Western blot method were applied to detect Caspase-3 and Caspase-9. Compared with the model control, the survival conditions of rats in all treatment groups were generally improved after PF treatment. LVEF was significantly increased, and both left ventricular end-diastolic inner diameter and left ventricular end-systolic inner diameter were significantly reduced. Moreover, pathologic examination showed that the myocardium degeneration of the rats treated with PF was decreased, including neater arrangement, more complete myofilament, more uniform gap and less interstitial collagen fibers. Furthermore, the mitochondrial structure of cardiomyocytes was significantly improved. The ultrastructure was clear, and the arrangement of myofilament was more regular. Also, the expression of Caspase-3 and Caspase-9 was inhibited, and apoptosis was obviously reduced in the PF treatment groups. BNP, TNF-α and IL-6 were also decreased and IL-10 was increased in the treated rats. PF could significantly improve the LVEF of rats. It decreased adverse left ventricular remodeling after myocardial infarction in rat models. The potential mechanism could be that PF decreased and inhibited BNP, TNF-α and IL-6, increased IL-10 and further inhibited the expression of Caspase-3 and Caspase-9, thus promoting ventricular remodeling.

Structural and electronic properties of CdSe/ZnS and ZnS/CdSe core/shell nanowires via first principles study

NASA Astrophysics Data System (ADS)

Rehman, Shafiq Ur; Li, H. M.; Ding, Z. J.

2018-05-01

First principles calculations have been performed to predict the structural stability and electronic structures of hydrogen passivated wurtzite CdSe/ZnS and ZnS/CdSe core/shell nanowires (CSNWs) in the [0001] direction. The calculated binding energy shows that ZnS/CdSe CSNWs are more stable than CdSe/ZnS CSNWs and the stability of ZnS/CdSe CSNWs increases with increasing the thickness of ZnS shell. The modulated electronic band gap demonstrates an increase when the size of both CSNWs is reduced, as a result of the quantum confinement effect. The core-to-shell chemical composition of atoms shows that a strong composition effect also exists in these CSNWs, which in turn affects their electronic properties. Our simulated results show that the photoemission spectra of the CSNWs can be significantly improved by tuning the energy gap of CSNWs.

Catalytic converter for purifying exhaust gases of internal combustion engines

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

Kakinuma, A.; Oya, H.

1980-06-24

A catalytic converter for purifying the exhaust gases of internal combustion engines is comprised of a cylindrical shell comprising a pair of half shells which form an inlet chamber, a catalyst chamber, and an outlet chamber, a catalyst element provided in the catalyst chamber, a cylindrical sealing member provided in the inlet chamber, and a damper member provided between the cylindrical shell and the sealing member. The sealing member engages to the cylindrical shell for sealing the gap between the cylindrical shell and the catalyst element.

ELECTRON-CAPTURE AND β-DECAY RATES FOR sd-SHELL NUCLEI IN STELLAR ENVIRONMENTS RELEVANT TO HIGH-DENSITY O–NE–MG CORES

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

Suzuki, Toshio; Toki, Hiroshi; Nomoto, Ken’ichi, E-mail: suzuki@phys.chs.nihon-u.ac.jp

Electron-capture and β-decay rates for nuclear pairs in the sd-shell are evaluated at high densities and high temperatures relevant to the final evolution of electron-degenerate O–Ne–Mg cores of stars with initial masses of 8–10 M{sub ⊙}. Electron capture induces a rapid contraction of the electron-degenerate O–Ne–Mg core. The outcome of rapid contraction depends on the evolutionary changes in the central density and temperature, which are determined by the competing processes of contraction, cooling, and heating. The fate of the stars is determined by these competitions, whether they end up with electron-capture supernovae or Fe core-collapse supernovae. Since the competing processes aremore » induced by electron capture and β-decay, the accurate weak rates are crucially important. The rates are obtained for pairs with A = 20, 23, 24, 25, and 27 by shell-model calculations in the sd-shell with the USDB Hamiltonian. Effects of Coulomb corrections on the rates are evaluated. The rates for pairs with A = 23 and 25 are important for nuclear Urca processes that determine the cooling rate of the O–Ne–Mg core, while those for pairs with A = 20 and 24 are important for the core contraction and heat generation rates in the core. We provide these nuclear rates at stellar environments in tables with fine enough meshes at various densities and temperatures for studies of astrophysical processes sensitive to the rates. In particular, the accurate rate tables are crucially important for the final fates of not only O–Ne–Mg cores but also a wider range of stars, such as C–O cores of lower-mass stars.« less

Health utility of patients with advanced gastrointestinal stromal tumors (GIST) after failure of imatinib and sunitinib: findings from GRID, a randomized, double-blind, placebo-controlled phase III study of regorafenib versus placebo.

PubMed

Poole, Chris D; Connolly, Mark P; Chang, Jane; Currie, Craig J

2015-07-01

In this analysis we report patients with advanced gastrointestinal stromal tumors (GIST) refractory to imatinib and sunitinib therapy as derived from the EuroQol-5D (EQ-5D) for progression-free (PF) and progressive disease health status. Data were analyzed from a phase III trial conducted at 57 hospitals in 17 countries (trial registration number, NCT01271712). Patients with advanced GIST were randomized (2:1) to receive blinded treatment using oral regorafenib 160 mg daily or placebo, plus best supportive care (BSC) in both groups, for the first 3 weeks of each 4-week cycle. EQ-5D-3L was administered on day 1 of each cycle before contact with their physician and before any study-related procedures. The effect of disease progression on the utility of EQ-5D was tested with paired-samples comparison and general linear mixed modeling (GLMM). One hundred and eighty five patients [93 % of the intention-to-treat (ITT) population] completed 803 EQ-5D questionnaires: 77.7 % in progression-free (PF) state, 6.5 % at progression, 13.9 % following first progression, and 1.9 % after second progression. Mean baseline utility was 0.767 (SD 0.221) with no significant between-group differences for active treatment and BSC. The first post-progression health state was 0.647 (SD 0.343), suggesting significantly impaired health-related quality of life after confirmed disease progression showed a decrease of -0.120 (paired samples t test, p = 0.001). GLMM showed no effect of study treatment or cycle number on utility. We demonstrate a significant and clinically meaningful difference in health state utility values between PF and progression. Utility values remained stable over successive regorafenib cycles after controlling for disease status and treatment type.

Influence of intentional femoral component flexion in navigated TKA on gap balance and sagittal anatomy.

PubMed

Roßkopf, J; Singh, P K; Wolf, P; Strauch, M; Graichen, H

2014-03-01

Navigation has proven its ability to accurately restore coronal leg axis; however, for a good clinical outcome, other factors such as sagittal anatomy and balanced gaps are at least as important. In a gap-balanced technique, the size of the flexion gap is equalled to that of the extension gap. Flexion of the femoral component has been described as a theoretical possibility to balance flexion and extension gap. Aim of this study was to assess whether intentional femoral component flexion is helpful in balancing TKA gaps and in restoring sagittal anatomy. One hundred and thirty-one patients with TKA were included in this study. Implantation was performed in a navigated, gap-balanced, tibia-first technique. The femoral component flexion needed to equal flexion to extension gap was calculated based upon the navigation data. The sagittal diameter, the anterior and posterior offset were measured pre- and postoperatively based on the lateral radiographs. Medial and lateral gaps in extension and flexion as well as flexion/extension gap differences pre- and postoperatively were analysed. Additionally range of motion (ROM) and patient satisfaction (SF 12) were obtained. To achieve equal flexion and extension gap, the femoral component was flexed in 120 out of 131 patients showing mean flexion of 2.9° (SD 2.2°; navigation data) and 3.1° (SD 2.0°; radiological analysis), respectively. Based on this technique, it was possible to balance the extension gap (<2 mm difference) in 130 out of 131 patients (99%) and the flexion gap in 119 out of 131 (91%). The difference between extension and flexion gap was reduced from 39 to 24 out of 131 patients (81%) on the medial side and from 69 to 28 on the lateral side (79%). The sagittal diameter was restored in 114 out of 131 cases (87%); however, anterior offset was significantly reduced by 1.3 mm (SD 3.9°), and posterior offset was significantly increased by 1.6 mm (SD 3.3°). No correlation between any navigation and radiological parameter was found with ROM and SF 12. The navigation-based, gap-balanced technique allows intentional flexion of the femoral component in order to balance gaps in more than 90% of primary TKA cases. Simultaneously, the sagittal diameter is restored in 87% of patients. However, to achieve equal gaps, the posterior offset is significantly increased by 1.6 mm and the femoral component is flexed by 3°. To evaluate the effect of this technique on the clinical outcome, future studies are needed. II.

Circadian adaptation of airline pilots during extended duration operations between the USA and Asia.

PubMed

Gander, Philippa; van den Berg, Margo; Mulrine, Hannah; Signal, Leigh; Mangie, Jim

2013-10-01

This study tracked circadian adaptation among airline pilots before, during, and after trips where they flew from Seattle (SEA) or Los Angeles (LAX) to Asia (7--9 time zones westward), spent 7--12 d in Asia, and then flew back to the USA. In Asia, pilots' exposures to local time cues and sleep opportunities were constrained by duty (short-haul flights crossing ≤ 1 time zone/24 h). Fourteen captains and 16 first officers participated (median age = 56 versus 48 yrs, p.U) < 0.001). Their sleep was monitored (actigraphy, duty/sleep diaries) from 3 d pre-trip to 5 d post-trip. For every flight, Karolinska Sleepiness and Samn-Perelli Fatigue scales and 5-min psychomotor vigilance task (PVT) tests were completed pre-flight and at top of descent (TOD). Participants had ≥ 3 d free of duty prior to outbound flight(s). From 72--24 h prior to departure (baseline sleep), mean total sleep/24 h (TST) = 7.00 h (SD = 1.18 h) and mean sleep efficiency = 87% (SD = 4.9%). Most pilots (23/30) flew direct to and from Asia, but 7 LAX-based pilots flew via a 1-d layover in Honolulu (HNL). On flights with ≥ 2 pilots, mean total in-flight sleep varied from 0.40 to 2.09 h outbound and from 0.74 to 1.88 h inbound. Duty patterns in Asia were variable, with ≤ 2 flights/d (mean flight duration = 3.53 h, SD = 0.53 h). TST on days 17 in Asia did not differ from baseline (p.F) = 0.2031). However, mean sleep efficiency was significantly lower than baseline on days 5--7 (p.F) = 0.0041). More pilots were on duty between 20:00 and 24:00 h on days 57 (mean = 21%) than on days 24 (mean = 14%). Sleep propensity distribution phase markers and chi-square periodogram analyses suggest that adaptation to local time was complete by day 4 in Asia. On pre-flight PVT tests in Asia, the slowest 10% of responses improved for flights departing 14:00--19:59 h (p.F) = 0.0484). At TOD, the slowest 10% of responses improved across days for flights arriving 14:00--19:59 h (p.F) = 0.0349) and 20:00--01:59 h (p.F) = 0.0379). Sleepiness and fatigue ratings pre-flight and at TOD did not change across days in Asia. TST on post-trip day 1 was longer than baseline (estimated mean extension = 1.68 h; adjusted p(t) < 0.0001). On all post-trip days, sleep efficiency was comparable to baseline. Sleep propensity distribution phase markers and chi-square periodogram analyses suggest complete readaptation in 12 d. Two opposing influences appeared to affect sleep and PVT performance across days in Asia: progressive circadian adaptation to local time and increasing duty during local night, which displaced sleep from the optimal physiological time. Cumulative sleep restriction across the return flight may explain the large rebound in TST on day 1 post-trip. Thereafter TST, sleep efficiency, and sleep timing suggest that readaptation was complete. Rapid post-trip readaptation may be facilitated by pilots having unconstrained nocturnal sleep opportunities, coupled with stronger patterns of family and social cues than in Asia.

Optical phonon modes of III-V nanoparticles and indium phosphide/II-VI core-shell nanoparticles: A Raman and infrared study

NASA Astrophysics Data System (ADS)

Manciu, Felicia Speranta

The prospects for realizing efficient nanoparticle light emitters in the visible/near IR for communications and bio-medical applications have benefited from progress in chemical fabrication of nanoparticles. III-V semiconductor nanopaticles such as GaP and InP are promising materials for the development of "blue" and "green" emitters, respectively, due to their large effective bandgaps. Enhanced emission efficiency has been achieved for core-shell nanoparticles, since inorganic shell materials increase electronic tunability and may decrease surface defects that often occur for nanoparticles capped with organic molecules. Also, the emission wavelength of InP nanoparticle cores can be tuned from green to red by changing the shell material in InP/II-VI core-shell nanoparticles. Investigations of phonon modes in nanocrystals are of both fundamental and applied interest. In the former case the optical phonon modes, such as surface/interface modes, are dependent on the nanoparticle dimensions, and also can provide information about dynamical properties of the nanoparticles and test the validity of various theoretical approaches. In the latter case the vibronic properties of nanoparticle emitters are controlled by confined phonons and modifications of the electron-phonon interaction by the confinement. Thus, the objective of the present thesis is the detailed study of the phonon modes of III-V nanoparticles (GaP and InP) and InP/II-VI core-shell nanoparticles by IR absorption and Raman scattering spectroscopies, and an elucidation of their complex vibrational properties. With the exception of three samples (two GaP and one InP), all samples were synthesized by a novel colloidal chemistry method, which does not requires added surfactant, but rather treatment of the corresponding precursors in octadecene noncoordinative solvent. Sample quality was characterized by ED, TEM and X-ray diffraction. Based on a comparison with a dielectric continuum model, the observed features in the IR and Raman results are assigned to the surface optical (SO) modes of the corresponding nanoparticles (InP and GaP), and to SO/interface modes for InP/II-VI core-shell nanoparticles. For the latter systems, an evaluation of the ratio of the shell material thickness to the core radius is achieved. Reasonable agreement is obtained between the Raman and FIR results, as well as with the calculations. (Abstract shortened by UMI.)

Order-Order Transition of C → sdG → sL → S in ABC Triblock Copolymer Thin Film Induced by Solvent Vapor.

PubMed

Luo, Chunxia; Huang, Weihuan; Han, Yanchun

2009-04-01

The morphology transition of polystyrene-block-poly(butadiene)-block-poly(2-vinylpyridine) (SBV) triblock thin film induced in benzene vapor showing weak selectivity for PS is investigated. The order-order transitions (OOT) in the sequence of core-shell cylinders (C), sphere in 'diblock gyroid' (sdG), sphere in lamella (sL) and sphere (S) are observed. The projection along (111) direction in Gyroid phase (sdG(111)) is found to epitaxially grow from C(001) in the film. Instead of sdG(111), sdG(110)(0.1875) develops to the phase of sL. Consequently, the film experiences the transition sequence of sdG(111) → sdG(211) → sdG(110)(0.25)  → sdG(110)(0.1875) between C and sL. The mechanism is analyzed from the total surface area of the blocks. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

First Electromagnetic Pulse Associated with a Gravitational-wave Event: Profile, Duration, and Delay

NASA Astrophysics Data System (ADS)

Lin, Da-Bin; Liu, Tong; Lin, Jie; Wang, Xiang-Gao; Gu, Wei-Min; Liang, En-Wei

2018-04-01

We study the first electromagnetic (EM) pulse after the gravitational-wave (GW) chirp signal, focusing on its profile and duration. It is found that the light curve, especially the steep decay (SD) phase, can be very different by adopting different viewing angles θ view of the jet shell. For an on-axis jet with a power-law radiation spectrum, the observed flux in the SD is proportional to {t}obs}-2-β with β being the spectral index and t obs being the observer time. Here, t obs = 0 is set at the time we observe the jet being ejected from the central engine. The SD may become steep by increasing θ view. We also study the bolometric luminosity L from a jet shell with a non-power-law radiation spectrum. For an on-axis jet, L ∝ t obs ‑3 is found in the SD. However, the SD is steeper than L\\propto {t}obs}-3 for radiation from an off-axis jet. The higher value of the θ view is, the steeper SD would be. Then, we suggest that the SD phase can be used to discriminate an off-axis jet from an on-axis jet. The reason for the above behaviors is discussed. In addition, we find that the duration of first EM pulse is close to its peak time, especially for θ view ∼ 20°. This result is consistent with that found in GW 170817/GRB 170817A. Thus, the jet corresponding to the prompt emission of GRB 170817A should be ejected immediately after the merger. Our results also reveal that the duration of the first EM pulse can provide information on the time to search for GWs.

Improving the In-Medium Similarity Renormalization Group via approximate inclusion of three-body effects

NASA Astrophysics Data System (ADS)

Morris, Titus; Bogner, Scott

2015-10-01

The In-Medium Similarity Renormalization Group (IM-SRG) has been applied successfully not only to several closed shell finite nuclei, but has recently been used to produce effective shell model interactions that are competitive with phenomenological interactions in the SD shell. A recent alternative method for solving of the IM-SRG equations, called the Magnus expansion, not only provides a computationally feasible route to producing observables, but also allows for approximate handling of induced three-body forces. Promising results for several systems, including finite nuclei, will be presented and discussed.

Test procedures and instructions for single shell tank saltcake cesium removal with crystalline silicotitanate

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

Duncan, J.B.

1997-01-07

This document provides specific test procedures and instructions to implement the test plan for the preparation and conduct of a cesium removal test, using Hanford Single Shell Tank Saltcake from tanks 24 t -BY- I 10, 24 1 -U- 108, 24 1 -U- 109, 24 1 -A- I 0 1, and 24 t - S-102, in a bench-scale column. The cesium sorbent to be tested is crystalline siticotitanate. The test plan for which this provides instructions is WHC-SD-RE-TP-024, Hanford Single Shell Tank Saltcake Cesium Removal Test Plan.

In vivo imaging of the morphology and changes in pH along the gastrointestinal tract of Japanese medaka by photonic band-gap hydrogel microspheres.

PubMed

Du, Xuemin; Lei, Ngai-Yu; Hu, Peng; Lei, Zhang; Ong, Daniel Hock-Chun; Ge, Xuewu; Zhang, Zhicheng; Lam, Michael Hon-Wah

2013-07-17

Colloidal crystalline microspheres with photonic band-gap properties responsive to media pH have been developed for in vivo imaging purposes. These colloidal crystalline microspheres were constructed from monodispersed core-shell nano-size particles with poly(styrene-co-acrylic acid) (PS-co-PAA) cores and poly(acrylic acid-co-N-isopropylacrylamide) (PAA-co-PNIPAM) hydrogel shells cross-linked by N,N'-methylenebisacrylamide. A significant shift in the photonic band-gap properties of these colloidal crystalline microspheres was observed in the pH range of 4-5. This was caused by the discontinuous volume phase transition of the hydrogel coating, due to the protonation/deprotonation of its acrylic acid moieties, on the core-shell nano-sized particles within the microspheres. The in vivo imaging capability of these pH-responsive photonic microspheres was demonstrated on a test organism - Japanese medaka, Oryzia latipes - in which the morphology and change in pH along their gastrointestinal (GI) tracts were revealed under an ordinary optical microscope. This work illustrates the potential of stimuli-responsive photonic band-gap materials in tissue-/organ-level in vivo bio-imaging. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of the finescale timing of repeated signals: does shell rapping in hermit crabs signal stamina?

PubMed

Briffa; Elwood

2000-01-01

Hermit crabs, Pagurus bernhardus, sometimes exchange shells after a period of shell rapping, when the initiating or attacking crab brings its shell rapidly and repeatedly into contact with the shell of the noninitiator or defender in a series of bouts. Bouts are separated by pauses, and raps within bouts are separated by very short periods called 'gaps'. Since within-contest variation is missed when signals are studied by averaging performance rates over entire contests, we analysed the fine within-bout structure of this repeated, aggressive signal. We found that the pattern is consistent with high levels of fatigue in initiators. The duration of the gaps between individual raps increased both within bouts and from bout to bout, and we conclude that this activity is costly to perform. Furthermore, long pauses between bouts is correlated with increased vigour of rapping in the subsequent bout, which suggests that the pause allows for recovery from fatigue induced by rapping. These between-bout pauses may be assessed by noninitiators and provide a signal of stamina. Copyright 2000 The Association for the Study of Animal Behaviour.

Distinguishing between old and modern permafrost sources in the northeast Siberian land-shelf system with compound-specific δ2H analysis

NASA Astrophysics Data System (ADS)

Vonk, Jorien E.; Tesi, Tommaso; Bröder, Lisa; Holmstrand, Henry; Hugelius, Gustaf; Andersson, August; Dudarev, Oleg; Semiletov, Igor; Gustafsson, Örjan

2017-08-01

Pleistocene ice complex permafrost deposits contain roughly a quarter of the organic carbon (OC) stored in permafrost (PF) terrain. When permafrost thaws, its OC is remobilized into the (aquatic) environment where it is available for degradation, transport or burial. Aquatic or coastal environments contain sedimentary reservoirs that can serve as archives of past climatic change. As permafrost thaw is increasing throughout the Arctic, these reservoirs are important locations to assess the fate of remobilized permafrost OC.

We here present compound-specific deuterium (δ2H) analysis on leaf waxes as a tool to distinguish between OC released from thawing Pleistocene permafrost (ice complex deposits; ICD) and from thawing Holocene permafrost (from near-surface soils). Bulk geochemistry (%OC; δ13C; %total nitrogen, TN) was analyzed as well as the concentrations and δ2H signatures of long-chain n-alkanes (C21 to C33) and mid- to long-chain n-alkanoic acids (C16 to C30) extracted from both ICD-PF samples (n = 9) and modern vegetation and O-horizon (topsoil-PF) samples (n = 9) from across the northeast Siberian Arctic. Results show that these topsoil-PF samples have higher %OC, higher OC / TN values and more depleted δ13C-OC values than ICD-PF samples, suggesting that these former samples trace a fresher soil and/or vegetation source. Whereas the two investigated sources differ on the bulk geochemical level, they are, however, virtually indistinguishable when using leaf wax concentrations and ratios. However, on the molecular isotope level, leaf wax biomarker δ2H values are statistically different between topsoil PF and ICD PF. For example, the mean δ2H value of C29 n-alkane was -246 ± 13 ‰ (mean ± SD) for topsoil PF and -280 ± 12 ‰ for ICD PF. With a dynamic isotopic range (difference between two sources) of 34 to 50 ‰; the isotopic fingerprints of individual, abundant, biomarker molecules from leaf waxes can thus serve as endmembers to distinguish between these two sources. We tested this molecular δ2H tracer along with another source-distinguishing approach, dual-carbon (δ13C-Δ14C) isotope composition of bulk OC, for a surface sediment transect in the Laptev Sea. Results show that general offshore patterns along the shelf-slope transect are similar, but the source apportionment between the approaches vary, which may highlight the advantages of either. This study indicates that the application of δ2H leaf wax values has potential to serve as a complementary quantitative measure of the source and differential fate of OC thawed out from different permafrost compartments.

Greenhouse Effect: Temperature of a Metal Sphere Surrounded by a Glass Shell and Heated by Sunlight

ERIC Educational Resources Information Center

Nguyen, Phuc H.; Matzner, Richard A.

2012-01-01

We study the greenhouse effect on a model satellite consisting of a tungsten sphere surrounded by a thin spherical, concentric glass shell, with a small gap between the sphere and the shell. The system sits in vacuum and is heated by sunlight incident along the "z"-axis. This development is a generalization of the simple treatment of the…

Rate theory of solvent exchange and kinetics of Li(+) - BF4 (-)/PF6 (-) ion pairs in acetonitrile.

PubMed

Dang, Liem X; Chang, Tsun-Mei

2016-09-07

In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li(+) and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li(+) in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li(+)-[BF4] and Li(+)-[PF6] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li(+). We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li(+)-[BF4] and Li(+)-[PF6] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.

Rate theory of solvent exchange and kinetics of Li+ - BF4-/PF6- ion pairs in acetonitrile

NASA Astrophysics Data System (ADS)

Dang, Liem X.; Chang, Tsun-Mei

2016-09-01

In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li+ and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li+ in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li+-[BF4] and Li+-[PF6] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li+. We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li+-[BF4] and Li+-[PF6] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.

Increasing comorbidity is associated with worsening physical function and pain after primary total knee arthroplasty.

PubMed

Hilton, Maren E; Gioe, Terence; Noorbaloochi, Siamak; Singh, Jasvinder A

2016-10-07

Previous studies suggested that pre-operative comorbidity was a risk factor for worse outcomes after TKA. To our knowledge, studies have not examined whether postoperative changes in comorbidity impact pain and function outcomes longitudinally. Our objective was to examine if increasing comorbidity postoperatively is associated with worsening physical function and pain after primary total knee arthroplasty (TKA). We performed a retrospective chart review of veterans who had completed Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form-36 (SF36) surveys at regular intervals after primary TKA. Comorbidity was assessed using a variety of scales: validated Charlson comorbidity index score, and a novel Arthroplasty Comorbidity Severity Index score (Including medical index, local musculoskeletal index [including lower extremity and spine] and TKA-related index subscales; higher scores are worse ), at multiple time-points post-TKA. We used mixed model linear regression to examine the association of worsening comorbidity post-TKA with change in WOMAC and SF-36 scores in the subsequent follow-up periods, controlling for age, length of follow-up, and repeated observations. The study cohort consisted of 124 patients with a mean age of 71.7 years (range 58.6-89.2, standard deviation (SD) 6.9) followed for a mean of 4.9 years post-operatively (range 1.3-11.4; SD 2.8). We found that post-operative worsening of the Charlson Index score was significantly associated with worsening SF-36 Physical Function (PF) (beta coefficient (ß) = -0.07; p < 0.0001), SF-36 Bodily Pain (BP) (ß = -0.06; p = 0.002), and WOMAC PF subscale (ß = 0.08; p < 0.001; higher scores are worse) scores, in the subsequent periods. Worsening novel medical index subscale scores were significantly associated with worsening SF-36 PF scores (ß = -0.03; p = 0.002), SF-36 BP (ß = -0.04; p < 0.001) and showed a non-significant trend for worse WOMAC PF scores (ß = 0.02; p = 0.11) subsequently. Local musculoskeletal index subscale scores were significantly associated with worsening SF-36 PF (ß = -0.05; p = 0.001), SF-36 BP (ß = -0.04; p = 0.03) and WOMAC PF (ß = 0.06; p = 0.01) subsequently. None of the novel index subscale scores were significantly associated with WOMAC pain scores. TKA complications, as assessed by TKA-related index subscale,  were not significantly associated with SF-36 or WOMAC domain scores. Increasing Charlson index as well as novel medical and local musculoskeletal index subscale scores (from novel Arthroplasty  Comorbidity Severity Index) post-TKA correlated with subsequent worsening of physical function and pain outcomes post-TKA. Further studies should examine which comorbidity management could have the greatest impact on these outcomes.

Impact of bisphenol A (BPA) on early embryo development in the marine mussel Mytilus galloprovincialis: Effects on gene transcription.

PubMed

Balbi, Teresa; Franzellitti, Silvia; Fabbri, Rita; Montagna, Michele; Fabbri, Elena; Canesi, Laura

2016-11-01

Bisphenol A (BPA), a monomer used in plastic manufacturing, is weakly estrogenic and a potential endocrine disruptor in mammals. Although it degrades quickly, it is pseudo-persistent in the environment because of continual inputs, with reported concentrations in aquatic environments between 0.0005 and 12 μg/L. BPA represents a potential concern for aquatic ecosystems, as shown by its reproductive and developmental effects in aquatic vertebrates. In invertebrates, endocrine-related effects of BPA were observed in different species and experimental conditions, with often conflicting results, indicating that the sensitivity to this compound can vary considerably among related taxa. In the marine mussel Mytilus galloprovincialis BPA was recently shown to affect early development at environmental concentrations. In this work, the possible effects of BPA on mussel embryos were investigated at the molecular level by evaluating transcription of 13 genes, selected on the basis of their biological functions in adult mussels. Gene expression was first evaluated in trocophorae and D-veligers (24 and 48 h post fertilization) grown in physiological conditions, in comparison with unfertilized eggs. Basal expressions showed a general up-regulation during development, with distinct transcript levels in trocophorae and D-veligers. Exposure of fertilized eggs to BPA (10 μg/L) induced a general upregulation at 24 h pf, followed by down regulation at 48 h pf. Mytilus Estrogen Receptors, serotonin receptor and genes involved in biomineralization (Carbonic Anydrase and Extrapallial Protein) were the most affected by BPA exposure. At 48 h pf, changes in gene expression were associated with irregularities in shell formation, as shown by scanning electron microscopy (SEM), indicating that the formation of the first shelled embryo, a key step in mussel development, represents a sensitive target for BPA. Similar results were obtained with the natural estrogen 17β-estradiol. The results demonstrate that BPA and E 2 can affect Mytilus early development through dysregulation of gene transcription. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fano-like resonance phenomena by flexural shell modes in sound transmission through two-dimensional periodic arrays of thin-walled hollow cylinders

NASA Astrophysics Data System (ADS)

Kosevich, Yuriy A.; Goffaux, Cecile; Sánchez-Dehesa, Jose

2006-07-01

It is shown that the n=2 and 3 flexural shell vibration modes of thin-walled hollow cylinders result in Fano-like resonant enhancement of sound wave transmission through or reflection from two-dimensional periodic arrays of these cylinders in air. The frequencies of the resonant modes are well described by the analytical theory of flexural (circumferential) modes of thin-walled hollow cylinders and are confirmed by finite-difference time-domain simulations. When the modes are located in the band gaps of the phononic crystal, an enhancement of the band-gap widths is produced by the additional restoring forces caused by the flexural shell deformations. Our conclusions provide an alternative method for the vibration control of airborne phononic crystals.

Electrical insulation system for the shell-vacuum vessel and poloidal field gap in the ZTH machine

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

Reass, W.A.; Ballard, E.O.

1989-01-01

The electrical insulation systems for the ZTH machine have many unusual design problems. The poloidal field gap insulation must be capable of conforming to poloidal and toroidal contours, provide a 25 kV hold off, and sufficiently adhere to the epoxy back fill between the overlapping conductors. The shell-vacuum vessel system will use stretchable and flexible insulation along with protective hats, boots and sleeves. The shell-vacuum vessel system must be able to withstand a 12.5 kV pulse with provision for thermal insulation to limit the effects of the 300{degrees}C vacuum vessel during operation and bakeout. Methodology required to provide the electricalmore » protection along with testing data and material characteristics will be presented. 7 figs.« less

Effect of Surface Functionalization on Structural and Optical Properties of Luminescent LaF₃:Sm Nanoparticles.

PubMed

Ansari, Anees A

2018-02-01

Samarium (Sm3+)-doped LaF3 nanoparticles (NPs) subsequently encapsulated with inert crystalline LaF3 and amorphous silica layers were prepared by polyol and sol-gel chemical process, respectively. These surface modified core/shell/SiO2-nanostructured were characterized by X-ray diffraction (XRD), FE-transmission electron microscopy (TEM), thermal analysis, FTIR, UV/Vis absorption, bang gap energy and photoluminescence spectroscopy. The FETEM, EDX and FTIR spectral studies clearly revealed that the silica layer has been formed surrounding the core-NPs. Comparative spectral analysis indicated that core/shell/SiO2-NPs revealed high solubility in aqueous and non-aqueous solvents. The decrease in band gap energy after surface growth of an inert LaF3 and silica shells is directly correlated to the increase in grain size. On comparing the emission intensity, a significant enhancement was observed after inert layer coating, whereas, it suppress after silica encapsulation due to the non-radiative transitions. The increase luminescent intensity after inert shell growth indicates that a significant amount of non-radiative centers existing on the surface of core/shell nanoparticles can be eliminated by the shielding effect of LaF3 shells. These observed results indicate that the as-prepared core/shell/SiO2-NPs could be highly useful in broad photonic based applications such as optical sensor/optical bio-probe and light emitting diode.

Wave Function Engineering in CdSe/PbS Core/Shell Quantum Dots.

PubMed

Wieliczka, Brian M; Kaledin, Alexey L; Buhro, William E; Loomis, Richard A

2018-05-25

The synthesis of epitaxial CdSe/PbS core/shell quantum dots (QDs) is reported. The PbS shell grows in a rock salt structure on the zinc blende CdSe core, thereby creating a crystal structure mismatch through additive growth. Absorption and photoluminescence (PL) band edge features shift to lower energies with increasing shell thickness, but remain above the CdSe bulk band gap. Nevertheless, the profiles of the absorption spectra vary with shell growth, indicating that the overlap of the electron and hole wave functions is changing significantly. This leads to over an order of magnitude reduction of absorption near the band gap and a large, tunable energy shift, of up to 550 meV, between the onset of strong absorption and the band edge PL. While the bulk valence and conduction bands adopt an inverse type-I alignment, the observed spectroscopic behavior is consistent with a transition between quasi-type-I and quasi-type-II behavior depending on shell thickness. Three effective mass approximation models support this hypothesis and suggest that the large difference in effective masses between the core and shell results in hole localization in the CdSe core and a delocalization of the electron across the entire QD. These results show the tuning of wave functions and transition energies in CdSe/PbS nanoheterostructures with prospects for use in optoelectronic devices for luminescent solar concentration or multiexciton generation.

Expressed var gene repertoire and variant surface antigen diversity in a shrinking Plasmodium falciparum population.

PubMed

Carlos, Bianca C; Fotoran, Wesley L; Menezes, Maria J; Cabral, Fernanda J; Bastos, Marcele F; Costa, Fabio T M; Sousa-Neto, Jayme A; Ribolla, Paulo E M; Wunderlich, Gerhard; Ferreira, Marcelo U

2016-11-01

The var gene-encoded erythrocyte membrane protein-1 of Plasmodium falciparum (PfEMP-1) is the main variant surface antigen (VSA) expressed on infected erythrocytes. The rate at which antibody responses to VSA expressed by circulating parasites are acquired depends on the size of the local VSA repertoire and the frequency of exposure to new VSA. Because parasites from areas with declining malaria endemicity, such as the Amazon, typically express a restricted PfEMP-1 repertoire, we hypothesized that Amazonians would rapidly acquire antibodies to most locally circulating VSA. Consistent with our expectations, the analysis of 5878 sequence tags expressed by 10 local P. falciparum samples revealed little PfEMP-1 DBL1α domain diversity. Among the most commonly expressed DBL1α types, 45% were shared by two or more independent parasite lines. Nevertheless, Amazonians displayed major gaps in their repertoire of anti-VSA antibodies, although the breadth of anti-VSA antibody responses correlated positively with their cumulative exposure to malaria. We found little antibody cross-reactivity even when testing VSA from related parasites expressing the same dominant DBL1α types. We conclude that variant-specific immunity to P. falciparum VSAs develops slowly despite the relatively restricted PfEMP-1 repertoire found in low-endemicity settings. Copyright © 2016 Elsevier Inc. All rights reserved.

A review: applications of the phase field method in predicting microstructure and property evolution of irradiated nuclear materials

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

Li, Yulan; Hu, Shenyang; Sun, Xin

Complex microstructure changes occur in nuclear fuel and structural materials due to the extreme environments of intense irradiation and high temperature. This paper evaluates the role of the phase field (PF) method in predicting the microstructure evolution of irradiated nuclear materials and the impact on their mechanical, thermal, and magnetic properties. The paper starts with an overview of the important physical mechanisms of defect evolution and the significant gaps in simulating microstructure evolution in irradiated nuclear materials. Then, the PF method is introduced as a powerful and predictive tool and its applications to microstructure and property evolution in irradiated nuclearmore » materials are reviewed. The review shows that 1) FP models can correctly describe important phenomena such as spatial dependent generation, migration, and recombination of defects, radiation-induced dissolution, the Soret effect, strong interfacial energy anisotropy, and elastic interaction; 2) The PF method can qualitatively and quantitatively simulate 2-D and 3-D microstructure evolution, including radiation-induced segregation, second phase nucleation, void migration, void and gas bubble superlattice formation, interstitial loop evolution, hydrate formation, and grain growth, and 3) The FP method correctly predicts the relationships between microstructures and properties. The final section is dedicated to a discussion of the strengths and limitations of the PF method, as applied to irradiation effects in nuclear materials.« less

The effects of two torque values on the screw preload of implant-supported prostheses with passive fit or misfit.

PubMed

Al-Otaibi, Hanan Nejer; Akeel, Riyadh Fadul

2014-01-01

To determine the effect of increased torque of the abutment screw and retorquing after 10 minutes on implant-supported fixed prostheses. Two strain gauges (SGs) were attached to four implants stabilized on an acrylic resin mandible. Four implant-supported frameworks were constructed to represent passive fit (PF) and different amounts of misfit (MF1, MF2, and MF3). Vertical misfit was measured using a traveling microscope. Each framework was torqued to 35 Ncm (the manufacturer's recommendation) and 40 Ncm, and the preload was recorded immediately and again after retorquing 10 minutes later (torque stage). The smallest gap was observed under the PF framework. Three-way analysis of variance revealed significant effects of the framework, torque value, and torque stage on preload. The PF showed the highest mean preload under both torque values. An independent-sample t test between the torque values revealed a statistically significant difference only for MF1 and MF2. A dependent-sample t test of the torque stage revealed a statistically significant difference at a torque value of 35 Ncm under the PF and MF3 frameworks. Increasing the torque value beyond the manufacturer's recommended amount and retorquing of the screws at 10 minutes after the initial torque did not necessarily lead to a significant increase in preload in full-arch implant-supported fixed prostheses, particularly under non-passively fitting frameworks.

Parametric Study on the Response of Compression-Loaded Composite Shells With Geometric and Material Imperfections

NASA Technical Reports Server (NTRS)

Hilburger, Mark W.; Starnes, James H., Jr.

2004-01-01

The results of a parametric study of the effects of initial imperfections on the buckling and postbuckling response of three unstiffened thinwalled compression-loaded graphite-epoxy cylindrical shells with different orthotropic and quasi-isotropic shell-wall laminates are presented. The imperfections considered include initial geometric shell-wall midsurface imperfections, shell-wall thickness variations, local shell-wall ply-gaps associated with the fabrication process, shell-end geometric imperfections, nonuniform applied end loads, and variations in the boundary conditions including the effects of elastic boundary conditions. A high-fidelity nonlinear shell analysis procedure that accurately accounts for the effects of these imperfections on the nonlinear responses and buckling loads of the shells is described. The analysis procedure includes a nonlinear static analysis that predicts stable response characteristics of the shells and a nonlinear transient analysis that predicts unstable response characteristics.

Thermoelectric properties of n and p-type cubic and tetragonal XTiO3 (X = Ba,Pb): A density functional theory study

NASA Astrophysics Data System (ADS)

Rahman, Gul; Rahman, Altaf Ur

2017-12-01

Thermoelectric properties of cubic (C) and tetragonal (T) BaTiO3 (BTO) and PbTiO3 (PTO) are investigated using density functional theory together with semiclassical Boltzmann's transport theory. Both electron and hole doped BTO and PTO are considered in 300-500 K temperature range. We observed that C-BTO has larger power factor(PF) when doped with holes, whereas n-type carrier concentration in C-PTO has larger PF. Comparing both BTO and PTO, C-PTO has larger figure of merit ZT. Tetragonal distortion reduces the Seebeck coefficient S in n-doped PTO, and the electronic structures revealed that such reduction in S is mainly caused by the increase in the optical band gaps (Γ - Γ and Γ-X).

Highly aqueous soluble CaF2:Ce/Tb nanocrystals: effect of surface functionalization on structural, optical band gap, and photoluminescence properties.

PubMed

Ansari, Anees A; Parchur, Abdul K; Kumar, Brijesh; Rai, S B

2016-12-01

The design of nanostructured materials with highly stable water-dispersion and luminescence efficiency is an important concern in nanotechnology and nanomedicine. In this paper, we described the synthesis and distinct surface modification on the morphological structure and optical (optical absorption, band gap energy, excitation, emission, decay time, etc.) properties of highly crystalline water-dispersible CaF 2 :Ce/Tb nanocrystals (core-nanocrystals). The epitaxial growth of inert CaF 2 and silica shell, respectively, on their surface forming as CaF 2 :Ce/Tb@CaF 2 (core/shell) and CaF 2 :Ce/Tb@CaF 2 @SiO 2 (core/shell/SiO 2 ) nanoarchitecture. X-ray diffraction and transmission electron microscope image shows that the nanocrystals were in irregular spherical phase, highly crystalline (~20 nm) with narrow size distribution. The core/shell nanocrystals confirm that the surface coating is responsible in the change of symmetrical nanostructure, which was determined from the band gap energy and luminescent properties. It was found that an inert inorganic shell formation effectively enhances the luminescence efficiency and silica shell makes the nanocrystals highly water-dispersible. In addition, Ce 3+ /Tb 3+ -co-doped CaF 2 nanocrystals show efficient energy transfer from Ce 3+ to Tb 3+ ion and strong green luminescence of Tb 3+ ion at 541 nm( 5 D 4 → 7 F 5 ). Luminescence decay curves of core and core/shell nanocrystals were fitted using mono and biexponential equations, and R 2 regression coefficient criteria were used to discriminate the goodness of the fitted model. The lifetime values for the core/shell nanocrystals are higher than core-nanocrystals. Considering the high stable water-dispersion and intensive luminescence emission in the visible region, these luminescent core/shell nanocrystals could be potential candidates for luminescent bio-imaging, optical bio-probe, displays, staining, and multianalyte optical sensing. A newly designed CaF 2 :Ce/Tb nanoparticles via metal complex decomposition rout shows high dispersibility in aqueous solvents with enhanced photoluminescence. The epitaxial growth of inert CaF 2 shell and further amorphous silica, respectively, enhanced their optical and luminescence properties, which is highly usable for luminescent biolabeling, and optical bioprobe etc.

Projected shell model description of N = 114 superdeformed isotone nuclei

NASA Astrophysics Data System (ADS)

Guo, R. S.; Chen, L. M.; Chou, C. H.

2006-03-01

A systematic description of the yrast superdeformed (SD) bands in N = 114, Z = 80-84 isotone nuclei using the projected shell model is presented. The calculated γ-ray energies, moment of inertia and M1 transitions are compared with the data for which spin is assigned. Excellent agreement with the available data for all isotones is obtained. The calculated electromagnetic properties provide a microscopic understanding of those measured nuclei. Some predictions in superdeformed nuclei are also discussed.

Is there a rationale to use a dual mobility poly insert for failed Birmingham metal-on-metal hip replacements? A retrieval analysis.

PubMed

Renner, Lisa; Faschingbauer, Martin; Boettner, Friedrich

2015-08-01

Previous studies showed poor outcomes for patients undergoing revision of failed metal-on-metal total hip arthroplasty (MoM-THA) and resurfacing (RS) with an increased risk of dislocation. Dual mobility inserts are an option to retain the acetabular component and change the metal-on-metal bearing to plastic-on-metal. The current study analyzes the rationale for the off-label use of a dual mobility poly insert (MDM X3, Stryker, Mahwah, NJ) in a Birmingham metal shell (Smith & Nephew, Memphis, TN). Based on retrievals from the implant database the study compared the clearance between 20 BHR shells, 31 MDM poly inserts and 24 ADM acetabular components of different sizes. The radial clearance was calculated for each possible combination of implants [n = 81 (MDM/BHR) and n = 119 (MDM/ADM)]. An MDM mobile bearing poly insert in an ADM shell has an average clearance of 0.314 mm (SD 0.031) compared to 0.234 mm (SD 0.030) in a BHR shell (p < 0.01). The minimal clearance is 0.246 and 0.163 mm, respectively. 30.9 % of the MDM/BHR clearances were within the range of the MDM/ADM bearing and 88.9 % had a clearance of more than 0.2 mm. Clearances of the MDM poly insert in a BHR shell are reduced, and although the majority of combinations appear safe, the indication needs to be made on an individual base carefully considering alternative treatment options.

Increased platelet factor 4 and aberrant permeability of follicular fluid in PCOS.

PubMed

Huang, Chu-Chun; Chou, Chia-Hung; Chen, Shee-Uan; Ho, Hong-Nerng; Yang, Yu-Shih; Chen, Mei-Jou

2018-05-17

Abnormal folliculogenesis is one of the cardinal presentations of polycystic ovarian syndrome (PCOS) and permeability of follicular wall has been proposed to be involved in the normal follicular growth. However, whether or not there is a change in intrafollicular permeability underlies PCOS is unknown. This was a tertiary center-based case-control study. From 2014 to 2015, thirteen patients with PCOS who underwent in vitro fertilization-embryo transfer (IVF-ET) were enrolled. Eleven normo-ovulatory patients who underwent IVF-ET due to male factor and/or tubal factor infertility were enrolled as the control group. The influence of ovarian follicular fluid (FF) on endothelial cell permeability was evaluated using a human umbilical vein endothelial cell monolayer permeability assay. The intrafollicular expression profiles of angiogenesis-related proteins were analyzed using a Human Angiogenesis Protein Array Kit. The FF from PCOS patients caused significantly poorer endothelial cell permeability comparing with the effect of FF from the control group (46% ± 12% vs. 58% ± 9%, P = 0.023). Among the 55 angiogenesis-related proteins tested, there was a significantly higher level of intrafollicular platelet factor 4 (PF4) and PF4/IL-8 complex in the PCOS group (p = 0.004). The anti-permeability effect of PF4 was related to the decrease in the intercellular gaps and antagonistic binding with IL-8. Our study provides the first evidence of the pathophysiologic contribution of the well-known angiostatic protein, PF4, on human reproductive biology. The increase of the intrafollicular PF4 and its anti-permeability effect might affect the formation of FF and folliculogenesis in PCOS. Copyright © 2018. Published by Elsevier B.V.

Aquaporin 0 Modulates Lens Gap Junctions in the Presence of Lens-Specific Beaded Filament Proteins

PubMed Central

Kumari, Sindhu; Gao, Junyuan; Mathias, Richard T.; Sun, Xiurong; Eswaramoorthy, Amizhdini; Browne, Nicholas; Zhang, Nigel

2017-01-01

Purpose The objective of this study was to understand the molecular and physiologic mechanisms behind the lens cataract differences in Aquaporin 0-knockout-Heterozygous (AQP0-Htz) mice developed in C57 and FVB (lacks beaded filaments [BFs]) strains. Methods Lens transparency was studied using dark field light microscopy. Water permeability (Pf) was measured in fiber cell membrane vesicles. Western blotting/immunostaining was performed to verify expression of BF proteins and connexins. Microelectrode-based intact lens intracellular impedance was measured to determine gap junction (GJ) coupling resistance. Lens intracellular hydrostatic pressure (HP) was determined using a microelectrode/manometer system. Results Lens opacity and spherical aberration were more distinct in AQP0-Htz lenses from FVB than C57 strains. In either background, compared to wild type (WT), AQP0-Htz lenses showed decreased Pf (approximately 50%), which was restored by transgenic expression of AQP1 (TgAQP1/AQP0-Htz), but the opacities and differences between FVB and C57 persisted. Western blotting revealed no change in connexin expression levels. However, in C57 AQP0-Htz and TgAQP1/AQP0-Htz lenses, GJ coupling resistance decreased approximately 2.8-fold and the HP gradient decreased approximately 1.9-fold. Increased Pf in TgAQP1/AQP0-Htz did not alter GJ coupling resistance or HP. Conclusions In C57 AQP0-Htz lenses, GJ coupling resistance decreased. HP reduction was smaller than the coupling resistance reduction, a reflection of an increase in fluid circulation, which is one reason for the less severe cataract in C57 than FVB. Overall, our results suggest that AQP0 modulates GJs in the presence of BF proteins to maintain lens transparency and homeostasis. PMID:29196765

Aquaporin 0 Modulates Lens Gap Junctions in the Presence of Lens-Specific Beaded Filament Proteins.

PubMed

Kumari, Sindhu; Gao, Junyuan; Mathias, Richard T; Sun, Xiurong; Eswaramoorthy, Amizhdini; Browne, Nicholas; Zhang, Nigel; Varadaraj, Kulandaiappan

2017-12-01

The objective of this study was to understand the molecular and physiologic mechanisms behind the lens cataract differences in Aquaporin 0-knockout-Heterozygous (AQP0-Htz) mice developed in C57 and FVB (lacks beaded filaments [BFs]) strains. Lens transparency was studied using dark field light microscopy. Water permeability (Pf) was measured in fiber cell membrane vesicles. Western blotting/immunostaining was performed to verify expression of BF proteins and connexins. Microelectrode-based intact lens intracellular impedance was measured to determine gap junction (GJ) coupling resistance. Lens intracellular hydrostatic pressure (HP) was determined using a microelectrode/manometer system. Lens opacity and spherical aberration were more distinct in AQP0-Htz lenses from FVB than C57 strains. In either background, compared to wild type (WT), AQP0-Htz lenses showed decreased Pf (approximately 50%), which was restored by transgenic expression of AQP1 (TgAQP1/AQP0-Htz), but the opacities and differences between FVB and C57 persisted. Western blotting revealed no change in connexin expression levels. However, in C57 AQP0-Htz and TgAQP1/AQP0-Htz lenses, GJ coupling resistance decreased approximately 2.8-fold and the HP gradient decreased approximately 1.9-fold. Increased Pf in TgAQP1/AQP0-Htz did not alter GJ coupling resistance or HP. In C57 AQP0-Htz lenses, GJ coupling resistance decreased. HP reduction was smaller than the coupling resistance reduction, a reflection of an increase in fluid circulation, which is one reason for the less severe cataract in C57 than FVB. Overall, our results suggest that AQP0 modulates GJs in the presence of BF proteins to maintain lens transparency and homeostasis.

Relationship between isometric and dynamic strength in recreationally trained men.

PubMed

McGuigan, Michael R; Newton, Michael J; Winchester, Jason B; Nelson, Arnold G

2010-09-01

The purpose of this investigation was to examine the relationships between measures of maximal isometric force (peak force [PF]), rate of force development (RFD), vertical jump performance (VJ) and 1-repetition maximum (1RM) strength in recreationally trained men. The subjects in this study were 26 men ([mean +/- SD]: age 22 +/- 1 years; height 175 +/- 7 cm; mass 90 +/- 10 kg). They were tested for PF using the isometric midthigh pull exercise. The 1RM for the squat and bench press exercise were determined as a measure of dynamic strength. Explosive strength was measured as RFD from the isometric force-time curve. Correlations between the variables were calculated using Pearson product moment correlation coefficient. There was a nearly perfect correlation between measures of PF and 1RM squat (r = 0.97, p < 0.05) and 1RM bench press (r = 0.99, p < 0.05). The correlations were very strong between VJ and PF (r = 0.72, p < 0.05) and 1RM bench press (r = 0.70, p < 0.05). There were also strong correlations between VJ and 1RM squat (r = 0.69, p < 0.05). There were no significant correlations with RFD. The results showed that isometric maximum strength determined during the isometric midthigh pull test correlated well with 1RM and VJ testing. However, RFD measured during the same test did not appear to correlate as well with other measures. The isometric midthigh pull provides an efficient method for assessing strength in recreationally trained individuals. Practitioners wishing to obtain performance data related to maximum strength may wish to consider isometric testing as a less time intensive method of testing.

Scale invariance and longitudinal stability of the Physical Functioning Western Ontario and MacMaster Universities Osteoarthritis Index using the Rasch model.

PubMed

Ayala, Alba; Bilbao, Amaia; Garcia-Perez, Sonia; Escobar, Antonio; Forjaz, Maria João

2018-03-01

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) measures the quality of life of patients with osteoarthritis (OA), and there is a specific scale for the physical functioning dimension, the short version with seven items WOMAC-pf. This study describes the application of the Rasch model to explore scale invariance and response stability of the WOMAC-pf short version across affected joint and over time. A sample of 884 patients with OA, from 15 hospitals in Spain, completed the WOMAC-pf before surgery (baseline) and at 3, 6 and 12 months post-surgery of hip or knee. The invariance by joint was explored through the differential item functioning (DIF) analysis of the Rasch model using baseline data, and time stability (DIF by time) were evaluated in stack data (each participant is represented four times, one by time point). Mean age of the patients was of 69.13 years (SD 10.01), 59.3% of them were women (n = 524), 59.2% had knee OA (n = 523) and 40.8% hip OA (n = 361). Item "putting on socks" showed DIF by joint and time. Fit to the Rasch model using stack data improved when this item was removed. Good reliability for individual use, local independency and unidimensionality of the models were confirmed. WOMAC-pf 7-item short version was invariant over time and joint when item "putting on socks" was removed. Researchers should carefully evaluate this item as it presents problems in scale invariance and stability, which could affect results when comparing data by joint or when computing change scores.

A Study of Multi-Λ Hypernuclei Within Spherical Relativistic Mean-Field Approach

NASA Astrophysics Data System (ADS)

Rather, Asloob A.; Ikram, M.; Usmani, A. A.; Kumar, B.; Patra, S. K.

2017-12-01

This research article is a follow up of an earlier work by M. Ikram et al., reported in Int. J. Mod. Phys. E 25, 1650103 (2016) where we searched for Λ magic numbers in experimentally confirmed doubly magic nucleonic cores in light to heavy mass region (i.e., 16 O-208 P b) by injecting Λ's into them. In the present manuscript, working within the state of the art relativistic mean field theory with the inclusion of Λ N and ΛΛ interaction in addition to nucleon-meson NL 3∗ effective force, we extend the search of lambda magic numbers in multi- Λ hypernuclei using the predicted doubly magic nucleonic cores 292120, 304120, 360132, 370132, 336138, 396138 of the elusive superheavy mass regime. In analogy to well established signatures of magicity in conventional nuclear theory, the prediction of hypernuclear magicities is made on the basis of one-, two- Λ separation energy ( S Λ, S 2Λ) and two lambda shell gaps ( δ 2Λ) in multi- Λ hypernuclei. The calculations suggest that the Λ numbers 92, 106, 126, 138, 184, 198, 240, and 258 might be the Λ shell closures after introducing the Λ's in the elusive superheavy nucleonic cores. The appearance of new lambda shell closures apart from the nucleonic ones predicted by various relativistic and non-relativistic theoretical investigations can be attributed to the relatively weak strength of the spin-orbit coupling in hypernuclei compared to normal nuclei. Further, the predictions made in multi- Λ hypernuclei under study resembles closely the magic numbers in conventional nuclear theory suggested by various relativistic and non-relativistic theoretical models. Moreover, in support of the Λ shell closure, the investigation of Λ pairing energy and effective Λ pairing gap has been made. We noticed a very close agreement of the predicted Λ shell closures with the survey made on the pretext of S Λ, S 2Λ, and δ 2Λ except for the appearance of magic numbers corresponding to Λ = 156 which manifest in Λ effective pairing gap and pairing energy. Also, the lambda single-particle spectrum is analyzed to mark the energy shell gap for further strengthening the predictions made on the basis of separation energies and shell gaps. Lambda and nucleon spin-orbit interactions are analyzed to confirm the reduction in magnitude of Λ spin-orbit interaction compared to the nucleonic case, however the interaction profile is similar in both the cases. Lambda and nucleon density distributions have been investigated to reveal the impurity effect of Λ hyperons which make the depression of central density of the core of superheavy doubly magic nuclei. Lambda skin structure is also seen.

Determining the Minimal Clinically Important Difference for Six-Minute Walk Distance in Fibromyalgia

PubMed Central

Kaleth, Anthony S.; Slaven, James E.; Ang, Dennis C.

2016-01-01

Objective To estimate the minimal clinically important difference (MCID) for 6-minute walk distance (6MWD) in patients with fibromyalgia (FM). Design Data from a recently completed trial that included 187 patients who completed the 6-minute walk test, Fibromyalgia Impact Questionnaire (FIQ), and Short-Form 36 (SF36) at 12 and 36 weeks were used to examine longitudinal changes in 6MWD. An anchor-based approach that used linear regression analyses was used to determine the MCID for 6MWD, using the total FIQ score (FIQ-Total) and SF36-physical function domain (SF36-PF) as clinical anchors. Results The mean (SD) change in 6MWD from baseline to week 36 was 34.4 (65.2) m (p<0.001). The anchor-based MCID’s for the 6MWD were 156 m and 167 m for the FIQ and SF36-PF, respectively. These MCID’s correspond with clinically meaningful improvements in FIQ (14% reduction) and SF36-PF (10 point increase). Conclusion The MCID for 6MWD in patients with FM was 156 to 167 m. These findings provide the first evidence of the change in 6MWD that is perceived by patients to be clinically meaningful. Further research using other MCID calculation methods is needed to refine estimates of the MCID for 6MWD in patients with FM. PMID:27003201

A Novel Malaria Pf/Pv Ab Rapid Diagnostic Test Using a Differential Diagnostic Marker Identified by Network Biology.

PubMed

Cho, Sung Jin; Lee, Jihoo; Lee, Hyun Jae; Jo, Hyun-Young; Sinniah, Mangalam; Kim, Hak-Yong; Chong, Chom-Kyu; Song, Hyun-Ok

2016-01-01

Rapid diagnostic tests (RDTs) can detect anti-malaria antibodies in human blood. As they can detect parasite infection at the low parasite density, they are useful in endemic areas where light infection and/or re-infection of parasites are common. Thus, malaria antibody tests can be used for screening bloods in blood banks to prevent transfusion-transmitted malaria (TTM), an emerging problem in malaria endemic areas. However, only a few malaria antibody tests are available in the microwell-based assay format and these are not suitable for field application. A novel malaria antibody (Ab)-based RDT using a differential diagnostic marker for falciparum and vivax malaria was developed as a suitable high-throughput assay that is sensitive and practical for blood screening. The marker, merozoite surface protein 1 (MSP1) was discovered by generation of a Plasmodium-specific network and the hierarchical organization of modularity in the network. Clinical evaluation revealed that the novel Malaria Pf/Pv Ab RDT shows improved sensitivity (98%) and specificity (99.7%) compared with the performance of a commercial kit, SD BioLine Malaria P.f/P.v (95.1% sensitivity and 99.1% specificity). The novel Malaria Pf/Pv Ab RDT has potential for use as a cost-effective blood-screening tool for malaria and in turn, reduces TTM risk in endemic areas.

Technology development in support of the TWRS process flowsheet. Revision 1

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

Washenfelder, D.J.

1995-10-11

The Tank Waste Remediation System is to treat and dispose of Hanford`s Single-Shell and Double-Shell Tank Waste. The TWRS Process Flowsheet, (WHC-SD-WM-TI-613 Rev. 1) described a flowsheet based on a large number of assumptions and engineering judgements that require verification or further definition through process and technology development activities. This document takes off from the TWRS Process Flowsheet to identify and prioritize tasks that should be completed to strengthen the technical foundation for the flowsheet.

Electronic, Optical, and Thermal Properties of Reduced-Dimensional Semiconductors

NASA Astrophysics Data System (ADS)

Huang, Shouting

Reduced-dimensional materials have attracted tremendous attention because of their new physics and exotic properties, which are of great interests for fundamental science. More importantly, the manipulation and engineering of matter on an atomic scale yield promising applications for many fields including nanoelectronics, nanobiotechnology, environments, and renewable energy. Because of the unusual quantum confinement and enhanced surface effect of reduced-dimensional materials, traditional empirical models suffer from necessary but unreliable parameters extracted from previously-studied bulk materials. In this sense, quantitative, parameter-free approaches are highly useful for understanding properties of reduced-dimensional materials and, furthermore, predicting their novel applications. The first-principles density functional theory (DFT) is proven to be a reliable and convenient tool. In particular, recent progress in many-body perturbation theory (MBPT) makes it possible to calculate excited-state properties, e.g., quasiparticle (QP) band gap and optical excitations, by the first-principles approach based on DFT. Therefore, during my PhD study, I employed first-principles calculations based on DFT and MBPT to systematically study fundamental properties of typical reduced-dimensional semiconductors, i.e., the electronic structure, phonons, and optical excitations of core-shell nanowires (NWs) and graphene-like two-dimensional (2D) structures of current interests. First, I present first-principles studies on how to engineer band alignments of nano-sized radial heterojunctions, Si/Ge core-shell NWs. Our calculation reveals that band offsets in these one-dimensional (1D) nanostructures can be tailored by applying axial strain or varying core-shell sizes. In particular, the valence band offset can be efficiently tuned across a wide range and even be diminished via applied strain. Two mechanisms contribute to this tuning of band offsets. Furthermore, varying the size of Si/Ge core-shell NWs and corresponding quantum confinement is shown to be efficient for modifying both valence and conduction band offsets simultaneously. Our proposed approaches to control band offsets in nano-sized heterojunctions may be of practical interest for nanoelectronic and photovoltaic applications. Additionally, I also studied the lattice vibrational modes of Si/Ge core-shell N-Ws. Our calculations show that the internal strain induced by the lattice mismatch between core and shell plays an important role in significantly shifting the frequency of characteristic optical modes of core-shell NWs. In particular, our simulation demonstrates that these frequency shifts can be detected by Raman-scattering experiments, giving rise to a convenient and nondestructive way to obtain structural information of core-shell materials. Meanwhile, another type of collective modes, the radial breathing modes (RBM), is identified in Si-core/Ge-shell NWs and their frequency dependence is explained by an elastic media model. Our studied vibrational modes and their frequency evolution are useful for thermoelectric applications based on core-shell nanostructures. Then I studied optical properties and exciton spectra of 2D semiconducting carbon structures. The energy spectra and wavefunctions of excitons in the 2D graphene derivatives, i.e., graphyne and graphane, are found to be strongly modified by quantum confinement, making them qualitatively different from the usual Rydberg series. However, their parity and optical selection rules are preserved. Thus a one-parameter hydrogenic model is applied to quantitatively explain the ab initio exciton spectra, and allows one to extrapolate the electron-hole binding energy from optical spectroscopies of 2D semiconductors without costly simulations. Meanwhile, our calculated optical absorption spectrum and enhanced spin singlet-triplet splitting project graphyne, an allotrope of graphene, as a good candidate for intriguing energy and biomedical applications. Lastly, we report first-principles results on electronic structures of 2D graphene-like system, i.e., silicene. For planar and simply buckled silicene structures, we confirm their zero-gap nature and show a significant renormalization of their Fermi velocity by including many-electron effects. However, the other two recently proposed silicene structures exhibit a finite band gap, indicating that they are gapped semiconductors instead of expected Dirac-fermion semimetals. This finite band gap of the latter two structures is preserved even with the Ag substrate included. The gap opening is explained by the symmetry breaking of the buckled structures. Moreover, our GW calculation reveals enhanced many-electron effects in these 2D structures. Finally the band gap of the latter two structures can be tuned in a wide range by applying strain.

MD simulations of the formation of stable clusters in mixtures of alkaline salts and imidazolium-based ionic liquids.

PubMed

Méndez-Morales, Trinidad; Carrete, Jesús; Bouzón-Capelo, Silvia; Pérez-Rodríguez, Martín; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

2013-03-21

Structural and dynamical properties of room-temperature ionic liquids containing the cation 1-butyl-3-methylimidazolium ([BMIM](+)) and three different anions (hexafluorophosphate, [PF6](-), tetrafluoroborate, [BF4](-), and bis(trifluoromethylsulfonyl)imide, [NTf2](-)) doped with several molar fractions of lithium salts with a common anion at 298.15 K and 1 atm were investigated by means of molecular dynamics simulations. The effect of the size of the salt cation was also analyzed by comparing these results with those for mixtures of [BMIM][PF6] with NaPF6. Lithium/sodium solvation and ionic mobilities were analyzed via the study of radial distribution functions, coordination numbers, cage autocorrelation functions, mean-square displacements (including the analysis of both ballistic and diffusive regimes), self-diffusion coefficients of all the ionic species, velocity and current autocorrelation functions, and ionic conductivity in all the ionic liquid/salt systems. We found that lithium and sodium cations are strongly coordinated in two different positions with the anion present in the mixture. Moreover, [Li](+) and [Na](+) cations were found to form bonded-like, long-lived aggregates with the anions in their first solvation shell, which act as very stable kinetic entities within which a marked rattling motion of salt ions takes place. With very long MD simulation runs, this phenomenon is proved to be on the basis of the decrease of self-diffusion coefficients and ionic conductivities previously reported in experimental and computational results.

Cycle stability of the electrochemical capacitors patterned with vertically aligned carbon nanotubes in an LiPF6-based electrolyte.

PubMed

Chiou, Yi-Deng; Tsai, Dah-Shyang; Lam, Hoa Hung; Chang, Chuan-hua; Lee, Kuei-Yi; Huang, Ying-Sheng

2013-09-07

The miniature ultracapacitors, with interdigitated electrodes of vertically aligned carbon nanotubes (VACNTs) and an inter-electrode gap of 20 μm, have been prepared in the LiPF6 organic electrolyte with and without PVdF-HFP gel. PVdF-HFP between two opposing electrodes enhances the device reliability, but lessens its power performance because of the extra diffusion resistance. Also noteworthy are the gel influences on the cycle stability. When the applied voltage is 2.0 or 2.5 V, both the LiPF6 and the gel capacitors exhibit excellent stability, typified by a retention ratio of ≥95% after 10,000 cycles. Their coulombic efficiencies quickly rise up, and hold steady at 100%. Nonetheless, when the applied voltage is 3.5 or 4.0 V, the cycle stability deteriorates, since the negative electrode potential descends below 0.9 V (vs. Li), leading to electrolyte decomposition and SEI formation. For the LiPF6 capacitor, its retention ratio could be around 60% after 10,000 cycles and the coulombic efficiency of 100% is difficult to reach throughout its cycle life. On the other hand, the gel capacitor cycles energy with a much higher retention ratio, >80% after 10,000 cycles, and a better coulombic efficiency, even though electrolyte decomposition still occurs. We attribute the superior stability of the gel capacitor to its extra diffusion resistance which slows down the performance deterioration.

ZnSe based semiconductor core-shell structures: From preparation to application

NASA Astrophysics Data System (ADS)

Sun, Chengcheng; Gu, Yarong; Wen, Weijia; Zhao, Lijuan

2018-07-01

Inorganic core-shell semiconductor materials have attracted increasing interest in recent years because of the unique structure, stable chemical properties and high performance in devices. With special properties such as a direct band-gap and excellent photoelectrical characteristics, ZnSe based semiconductor core-shell structures are promising materials for applications in such fields as photocatalysts, light-emitting diodes, solar cells, photodetectors, biomedical science and so on. However, few reviews on ZnSe based semiconductor core-shell structures have been reported so far. Therefore this manuscript mainly focuses on the research activities on ZnSe based semiconductor core-shell composites including various preparation methods and the applications of these core-shell structures, especially in photocatalysts, light emitting, solar cells and photodetectors. The possibilities and limitations of studies on ZnSe based semiconductor core-shell composites are also highlighted.

Analysis of different techniques to improve sound transmission loss in cylindrical shells

NASA Astrophysics Data System (ADS)

Oliazadeh, Pouria; Farshidianfar, Anooshiravan

2017-02-01

In this study, sound transmission through double- and triple-walled shells is investigated. The structure-acoustic equations based on Donnell's shell theory are presented and transmission losses calculated by this approach are compared with the transmission losses obtained according to Love's theory. An experimental set-up is also constructed to compare natural frequencies obtained from Donnell and Love's theories with experimental results in the high frequency region. Both comparisons show that Donnell's theory predicts the sound transmission characteristics and vibrational behavior better than Love's theory in the high frequency region. The transmission losses of the double- and triple-walled construction are then presented for various radii and thicknesses. Then the effects of air gap size as an important design parameter are studied. Sound transmission characteristics through a circular cylindrical shell are also computed along with consideration of the effects of material damping. Modest absorption is shown to greatly reduce the sound transmission at ring frequency and coincidence frequency. Also the effects of five common gases that are used for filling the gap are investigated.

Three-dimensional morphology of GaP-GaAs nanowires revealed by transmission electron microscopy tomography.

PubMed

Verheijen, Marcel A; Algra, Rienk E; Borgström, Magnus T; Immink, George; Sourty, Erwan; Enckevort, Willem J P van; Vlieg, Elias; Bakkers, Erik P A M

2007-10-01

We have investigated the morphology of heterostructured GaP-GaAs nanowires grown by metal-organic vapor-phase epitaxy as a function of growth temperature and V/III precursor ratio. The study of heterostructured nanowires with transmission electron microscopy tomography allowed the three-dimensional morphology to be resolved, and discrimination between the effect of axial (core) and radial (shell) growth on the morphology. A temperature- and precursor-dependent structure diagram for the GaP nanowire core morphology and the evolution of the different types of side facets during GaAs and GaP shell growth were constituted.

Field Application of SD Bioline Malaria Ag Pf/Pan Rapid Diagnostic Test for Malaria in Greece

PubMed Central

Tseroni, Maria; Pervanidou, Danai; Tserkezou, Persefoni; Rachiotis, George; Pinaka, Ourania; Baka, Agoritsa; Georgakopoulou, Theano; Vakali, Annita; Dionysopoulou, Martha; Terzaki, Irene; Marka, Andriani; Detsis, Marios; Evlampidou, Zafiroula; Mpimpa, Anastasia; Vassalou, Evdokia; Tsiodras, Sotirios; Tsakris, Athanasios; Kremastinou, Jenny; Hadjichristodoulou, Christos

2015-01-01

Greece, a malaria-free country since 1974, has experienced re-emergence of Plasmodium vivax autochthonous malaria cases in some agriculture areas over the last three years. In early 2012, an integrated control programme (MALWEST Project) was launched in order to prevent re-establishment of the disease. In the context of this project, the rapid diagnostic tests (RDT) of SD Bioline Malaria Ag Pf/Pan that detects hrp-2 and pan-LDH antigens were used. The aim of this study was to assess the field application of the RDT for the P. vivax diagnosis in comparison to light microscopy and polymerase chain reaction (PCR). A total of 955 samples were tested with all three diagnostic tools. Agreement of RDT against microscopy and PCR for the diagnosis of P. vivax was satisfactory (K value: 0.849 and 0.976, respectively). The sensitivity, specificity and positive predictive value of RDT against PCR was 95.6% (95% C.I.: 84.8-99.3), 100% (95% C.I.: 99.6-100.0) and 100% (95% CI: 91.7-100.0) respectively, while the sensitivity, specificity and positive predictive value of RDT against microscopic examination was 97.4% (95% C.I.: 86.1-99.6), 99.4% (95% C.I.: 98.6-99.8) and 86.1% (95% CI: 72.1-94.7), respectively. Our results indicate that RDT performed satisfactory in a non-endemic country and therefore is recommended for malaria diagnosis, especially in areas where health professionals lack experience on light microscopy. PMID:25803815

Relationship between Short-Form Health SF36 Questionnaire and oxygen uptake in healthy workers.

PubMed

Oscar García López, Oscar; Duarte Bedoya, Álvaro; Jiménez Gutiérrez, Alfonso; Burgos Postigo, Silvia

2016-03-01

Physical activity is associated with better health levels, and cardiopulmonary fitness is recognized as one of the best indicators of physical performance, which can be related with some items of quality of life (QoL). The aim of this study was to analyze the relationship between the QoL and cardiorespiratory fitness (VO2max) of healthy workers, measured with the Short-Form Health Survey SF36 and incremental cardiopulmonary Test. Sample was formed by 250 healthy workers (90 men, mean age 37.25 and 160 female, mean age 37.91). Analyzing the results, VO2's Mean values were higher in men (39.00 mL/kg/min SD 7.56) than in women (29.70 mL/kg/min SD 5.73) with significant differences (P<0.01). We found differences in all dimensions of SF36 indicating that men had higher scores than women, but significant differences between both are present only in physical functioning (PF) (P<0.01). Correlating the values obtained in the domains of Questionnaire SF36 and the Vo2 Max, correlation was significant (positive) in PF (0.276), bodily pain (0.189), general health (0.155), vitality (0.241) and mental health (0.129). Results showed that better cardiorespiratory fitness is related to higher scores in SF36. These findings suggest that if the values of oxygen uptake in healthy workers are higher, results in SF36 will be better. Therefore it can be assumed that having a good fitness means having a better QoL.

Field application of SD bioline malaria Ag Pf/Pan rapid diagnostic test for malaria in Greece.

PubMed

Tseroni, Maria; Pervanidou, Danai; Tserkezou, Persefoni; Rachiotis, George; Pinaka, Ourania; Baka, Agoritsa; Georgakopoulou, Theano; Vakali, Annita; Dionysopoulou, Martha; Terzaki, Irene; Marka, Andriani; Detsis, Marios; Evlampidou, Zafiroula; Mpimpa, Anastasia; Vassalou, Evdokia; Tsiodras, Sotirios; Tsakris, Athanasios; Kremastinou, Jenny; Hadjichristodoulou, Christos

2015-01-01

Greece, a malaria-free country since 1974, has experienced re-emergence of Plasmodium vivax autochthonous malaria cases in some agriculture areas over the last three years. In early 2012, an integrated control programme (MALWEST Project) was launched in order to prevent re-establishment of the disease. In the context of this project, the rapid diagnostic tests (RDT) of SD Bioline Malaria Ag Pf/Pan that detects hrp-2 and pan-LDH antigens were used. The aim of this study was to assess the field application of the RDT for the P. vivax diagnosis in comparison to light microscopy and polymerase chain reaction (PCR). A total of 955 samples were tested with all three diagnostic tools. Agreement of RDT against microscopy and PCR for the diagnosis of P. vivax was satisfactory (K value: 0.849 and 0.976, respectively). The sensitivity, specificity and positive predictive value of RDT against PCR was 95.6% (95% C.I.: 84.8-99.3), 100% (95% C.I.: 99.6-100.0) and 100% (95% CI: 91.7-100.0) respectively, while the sensitivity, specificity and positive predictive value of RDT against microscopic examination was 97.4% (95% C.I.: 86.1-99.6), 99.4% (95% C.I.: 98.6-99.8) and 86.1% (95% CI: 72.1-94.7), respectively. Our results indicate that RDT performed satisfactory in a non-endemic country and therefore is recommended for malaria diagnosis, especially in areas where health professionals lack experience on light microscopy.

Ab initio results for intermediate-mass, open-shell nuclei

NASA Astrophysics Data System (ADS)

Baker, Robert B.; Dytrych, Tomas; Launey, Kristina D.; Draayer, Jerry P.

2017-01-01

A theoretical understanding of nuclei in the intermediate-mass region is vital to astrophysical models, especially for nucleosynthesis. Here, we employ the ab initio symmetry-adapted no-core shell model (SA-NCSM) in an effort to push first-principle calculations across the sd-shell region. The ab initio SA-NCSM's advantages come from its ability to control the growth of model spaces by including only physically relevant subspaces, which allows us to explore ultra-large model spaces beyond the reach of other methods. We report on calculations for 19Ne and 20Ne up through 13 harmonic oscillator shells using realistic interactions and discuss the underlying structure as well as implications for various astrophysical reactions. This work was supported by the U.S. NSF (OCI-0904874 and ACI -1516338) and the U.S. DOE (DE-SC0005248), and also benefitted from the Blue Waters sustained-petascale computing project and high performance computing resources provided by LSU.

Tuning the thermoelectric properties of YNiBi half-Heusler alloy

NASA Astrophysics Data System (ADS)

Sharma, Sonu; Kumar, Pradeep

2018-04-01

A detail comparison between the results obtained for the electronic and transport properties of YNiBi half-Heusler alloy by local density approximation (LDA) and generalized gradient approximation (GGA) functionals with and without spin–orbit coupling (SOC) is presented. In the presence of SOC both functionals provide ∼30% smaller band gap. The transport coefficients computed without SOC confirm that YNiBi is a promising p-type thermoelectric material. However, with SOC at higher temperature, Seebeck coefficient was found to be negative because of the bipolar effects. Without SOC the computed power factor (PF) is found to be closer to the experimental value, while in the presence of SOC we have obtained comparatively smaller PF. No importance of SOC has been observed in the calculations of transport properties of the compound. The appropriate Ti doping in place of Y is predicted to significantly enhance the thermoelectric properties of YNiBi compound.

Thiolated DNA-based chemistry and control in the structure and optical properties of plasmonic nanoparticles with ultrasmall interior nanogap.

PubMed

Oh, Jeong-Wook; Lim, Dong-Kwon; Kim, Gyeong-Hwan; Suh, Yung Doug; Nam, Jwa-Min

2014-10-08

The design, synthesis and control of plasmonic nanostructures, especially with ultrasmall plasmonically coupled nanogap (∼1 nm or smaller), are of significant interest and importance in chemistry, nanoscience, materials science, optics and nanobiotechnology. Here, we studied and established the thiolated DNA-based synthetic principles and methods in forming and controlling Au core-nanogap-Au shell structures [Au-nanobridged nanogap particles (Au-NNPs)] with various interior nanogap and Au shell structures. We found that differences in the binding affinities and modes among four different bases to Au core, DNA sequence, DNA grafting density and chemical reagents alter Au shell growth mechanism and interior nanogap-forming process on thiolated DNA-modified Au core. Importantly, poly A or poly C sequence creates a wider interior nanogap with a smoother Au shell, while poly T sequence results in a narrower interstitial interior gap with rougher Au shell, and on the basis of the electromagnetic field calculation and experimental results, we unraveled the relationships between the width of the interior plasmonic nanogap, Au shell structure, electromagnetic field and surface-enhanced Raman scattering. These principles and findings shown in this paper offer the fundamental basis for the thiolated DNA-based chemistry in forming and controlling metal nanostructures with ∼1 nm plasmonic gap and insight in the optical properties of the plasmonic NNPs, and these plasmonic nanogap structures are useful as strong and controllable optical signal-generating nanoprobes.

Bait and the susceptibility of American lobsters Homarus americanus to epizootic shell disease.

PubMed

Bethoney, N David; Stokesbury, Kevin D E; Stevens, Bradley G; Altabet, Mark A

2011-05-24

Shell disease (SD) has been observed in lobster populations for almost a hundred years, but recently, rates of an epizootic form of shell disease (ESD) have increased in the southern New England (USA) area. A large proportion of fish in the diet of American lobsters Homarus americanus has been linked to increased rates of SD. Therefore, the use of fish as lobster bait may be linked to increased ESD rates in lobsters. Lobsters from the western portion of Martha's Vineyard, MA (41 degrees N, 71 degrees W), were randomly divided into 3 groups of 16 and exposed to dietary treatments (100% herring; 48% crab, 48% blue mussel and 4% plant matter; or 50% herring, 24% crab, 24% mussel, 2% plant matter) to determine if lobster tissue delta15N levels reflected diet. The results of the feeding experiment confirmed that differences in diet are observed in the delta15N levels of lobster muscle tissue. The delta15N levels of tissue samples from 175 wild lobsters with varying degrees of ESD were unrelated to ESD severity but did indicate lobsters were eating large amounts of fish (bait). This result does not support the speculation that fish used as bait is contributing to ESD outbreaks in portions of the southern New England area.

Molecular Structure of a 9-MDa Icosahedral Pyruvate Dehydrogenase Subcomplex Containing the E2 and E3 Enzymes Using Cryoelectron Microscopy*

PubMed Central

Milne, Jacqueline L. S.; Wu, Xiongwu; Borgnia, Mario J.; Lengyel, Jeffrey S.; Brooks, Bernard R.; Shi, Dan; Perham, Richard N.; Subramaniam, Sriram

2006-01-01

The pyruvate dehydrogenase multienzyme complexes are among the largest multifunctional catalytic machines in cells, catalyzing the production of acetyl CoA from pyruvate. We have previously reported the molecular architecture of an 11-MDa subcomplex comprising the 60-mer icosahedral dihydrolipoyl acetyltransferase (E2) decorated with 60 copies of the heterotetrameric (α2β2) 153-kDa pyruvate decarboxylase (E1) from Bacillus stearothermophilus (Milne, J. L. S., Shi, D., Rosenthal, P. B., Sunshine, J. S., Domingo, G. J., Wu, X., Brooks, B. R., Perham, R. N., Henderson, R., and Subramaniam, S. (2002) EMBO J. 21, 5587–5598). An annular gap of ~90 Å separates the acetyltransferase catalytic domains of the E2 from an outer shell formed of E1 tetramers. Using cryoelectron microscopy, we present here a three-dimensional reconstruction of the E2 core decorated with 60 copies of the homodimeric 100-kDa dihydrolipoyl dehydrogenase (E3). The E2E3 complex has a similar annular gap of ~75 Å between the inner icosahedral assembly of acetyltransferase domains and the outer shell of E3 homodimers. Automated fitting of the E3 coordinates into the map suggests excellent correspondence between the density of the outer shell map and the positions of the two best fitting orientations of E3. As in the case of E1 in the E1E2 complex, the central 2-fold axis of the E3 homodimer is roughly oriented along the periphery of the shell, making the active sites of the enzyme accessible from the annular gap between the E2 core and the outer shell. The similarities in architecture of the E1E2 and E2E3 complexes indicate fundamental similarities in the mechanism of active site coupling involved in the two key stages requiring motion of the swinging lipoyl domain across the annular gap, namely the synthesis of acetyl CoA and regeneration of the dithiolane ring of the lipoyl domain. PMID:16308322

Quality of life among children with beta-thalassemia major treated in Western Saudi Arabia.

PubMed

Ayoub, Mohammed D; Radi, Suhaib A; Azab, Abdulrahman M; Abulaban, Abdulrahman A; Balkhoyor, Abdulrahman H; Bedair, Seifeleslam W; Aljaouni, Soad K; Kari, Jameela A

2013-12-01

To assess the quality of life among children and adolescents with thalassemia major. This cross-sectional study used the Pediatric Quality of Life Inventory (PedsQL). Children and adolescents with beta-thalassemia major who attended the Day Care Unit at King Abdulaziz University Hospital, Jeddah, Saudi Arabia from October 2012 to February 2013 were surveyed. The questions highlighted 4 health status scales, namely physical functioning (PF), emotional functioning (EF), school performance (SC), and social functioning (SF). Scores were calculated for each patient and data were analyzed using the Statistical Package for Social Sciences. We recruited 46 children (60.9% males). The median age of the sample was 12 years (range, 2-18 years). Most patients (84.8%) had 3 weekly blood transfusions. The mean+/-SD physical functioning (PF) score was 57.2+/-25.9; the EF score was 74.1+/-20.3, SF score was 78.5+/-24, and SC score was 54.3+/-24.2. The PF score was significantly lower in patients with a family history of thalassemia (p=0.003), and in those whose families had low incomes (p=0.049). Conversely, the SF score was significantly higher in school-educated patients (p=0.01). The quality of life of thalassemic children is affected by multiple factors, such as family income and a family history of thalassemia. Education appeared to increase patient functionality. Supportive measures could improve the quality of life in thalassemic patients.

Predictable Particle Engineering: Programming the Energy Level, Carrier Generation, and Conductivity of Core-Shell Particles.

PubMed

Yuan, Conghui; Wu, Tong; Mao, Jie; Chen, Ting; Li, Yuntong; Li, Min; Xu, Yiting; Zeng, Birong; Luo, Weiang; Yu, Lingke; Zheng, Gaofeng; Dai, Lizong

2018-06-20

Core-shell structures are of particular interest in the development of advanced composite materials as they can efficiently bring different components together at nanoscale. The advantage of this structure greatly relies on the crucial design of both core and shell, thus achieving an intercomponent synergistic effect. In this report, we show that decorating semiconductor nanocrystals with a boronate polymer shell can easily achieve programmable core-shell interactions. Taking ZnO and anatase TiO 2 nanocrystals as inner core examples, the effective core-shell interactions can narrow the band gap of semiconductor nanocrystals, change the HOMO and LUMO levels of boronate polymer shell, and significantly improve the carrier density of core-shell particles. The hole mobility of core-shell particles can be improved by almost 9 orders of magnitude in comparison with net boronate polymer, while the conductivity of core-shell particles is at most 30-fold of nanocrystals. The particle engineering strategy is based on two driving forces: catechol-surface binding and B-N dative bonding and having a high ability to control and predict the shell thickness. Also, this approach is applicable to various inorganic nanoparticles with different components, sizes, and shapes.

An Explosive Bomb-Inspired Method to Prepare Collapsed and Ruptured Fe2 O3 /Nitrogen-Doped Carbon Capsules as Catalyst Support.

PubMed

Wu, Jie; Zhang, Hui; Feng, Yan; Zhang, Xiao; Yao, Tongjie; Lian, Yongfu

2017-12-01

Compared with integrated capsules, ruptured ones have better mass diffusion and transport properties due to large gaps in the shells. However, most studies focus on integrated capsules, whereas little attention has been paid to the ruptured counterparts. Herein, an explosive bomb-inspired method was employed to prepare collapsed and ruptured Fe 2 O 3 /nitrogen-doped carbon (CR-Fe 2 O 3 /NC) capsules by using polystyrene (PS) nanoparticles (NPs) as a hard template, and polypyrrole (PPy) with embedded Prussian blue (PB) NPs as the shell. During pyrolysis, PB is converted into Fe 2 O 3 , and PPy is carbonized to form NC. Importantly, the PS core decomposes into gas molecules, leading to high pressure inside of the capsule, which explodes the thin shell into pieces. The roles of shell thickness and amount of Fe 2 O 3 on determining the spherical or collapsed, and integrated or ruptured morphology were revealed. Taking advantage of structural merits, including large gaps, thin shells, low density, and high surface area, CR-Fe 2 O 3 /NC capsules were used as supports for Pd NPs. These capsules exhibited better catalytic activity than that of integrated ones. Due to the magnetic properties, they could be reused at least five times. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interfacial effect on the structural and optical properties of pure SnO2 and dual shells (ZnO; SiO2) coated SnO2 core-shell nanospheres for optoelectronic applications

NASA Astrophysics Data System (ADS)

Selvi, N.; Sankar, S.; Dinakaran, K.

2014-12-01

Nanocrystallites of SnO2 core and dual shells (ZnO, SiO2) coated SnO2 core-shell nanospheres were successfully synthesized by co-precipitation method. The as prepared and annealed samples were characterized by X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), High resolution transmission electron microscopy (HRTEM) and UV-Vis analysis. XRD pattern confirms the obtained SnO2 core with tetragonal rutile crystalline structure and the shell ZnO with hexagonal structure. FTIR result shows the functional groups present in the samples. The spherical morphology and the formation of the core-shell structures have been confirmed by HRTEM measurements. The UV-Vis showed that band gap is red shifted for as-prepared and the shells coated core-shell samples. From this investigation it can be concluded that the surface modification with different metal and insulating oxides strongly influences the optical properties of the core-shell materials which enhance their potential applications towards optical devices fabrication.

Dawning of the N =32 Shell Closure Seen through Precision Mass Measurements of Neutron-Rich Titanium Isotopes

NASA Astrophysics Data System (ADS)

Leistenschneider, E.; Reiter, M. P.; Ayet San Andrés, S.; Kootte, B.; Holt, J. D.; Navrátil, P.; Babcock, C.; Barbieri, C.; Barquest, B. R.; Bergmann, J.; Bollig, J.; Brunner, T.; Dunling, E.; Finlay, A.; Geissel, H.; Graham, L.; Greiner, F.; Hergert, H.; Hornung, C.; Jesch, C.; Klawitter, R.; Lan, Y.; Lascar, D.; Leach, K. G.; Lippert, W.; McKay, J. E.; Paul, S. F.; Schwenk, A.; Short, D.; Simonis, J.; Somà, V.; Steinbrügge, R.; Stroberg, S. R.; Thompson, R.; Wieser, M. E.; Will, C.; Yavor, M.; Andreoiu, C.; Dickel, T.; Dillmann, I.; Gwinner, G.; Plaß, W. R.; Scheidenberger, C.; Kwiatkowski, A. A.; Dilling, J.

2018-02-01

A precision mass investigation of the neutron-rich titanium isotopes Ti-5551 was performed at TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). The range of the measurements covers the N =32 shell closure, and the overall uncertainties of the Ti-5552 mass values were significantly reduced. Our results conclusively establish the existence of the weak shell effect at N =32 , narrowing down the abrupt onset of this shell closure. Our data were compared with state-of-the-art ab initio shell model calculations which, despite very successfully describing where the N =32 shell gap is strong, overpredict its strength and extent in titanium and heavier isotones. These measurements also represent the first scientific results of TITAN using the newly commissioned multiple-reflection time-of-flight mass spectrometer, substantiated by independent measurements from TITAN's Penning trap mass spectrometer.

Reversible patterning of spherical shells through constrained buckling

NASA Astrophysics Data System (ADS)

Marthelot, J.; Brun, P.-T.; Jiménez, F. López; Reis, P. M.

2017-07-01

Recent advances in active soft structures envision the large deformations resulting from mechanical instabilities as routes for functional shape morphing. Numerous such examples exist for filamentary and plate systems. However, examples with double-curved shells are rarer, with progress hampered by challenges in fabrication and the complexities involved in analyzing their underlying geometrical nonlinearities. We show that on-demand patterning of hemispherical shells can be achieved through constrained buckling. Their postbuckling response is stabilized by an inner rigid mandrel. Through a combination of experiments, simulations, and scaling analyses, our investigation focuses on the nucleation and evolution of the buckling patterns into a reticulated network of sharp ridges. The geometry of the system, namely, the shell radius and the gap between the shell and the mandrel, is found to be the primary ingredient to set the surface morphology. This prominence of geometry suggests a robust, scalable, and tunable mechanism for reversible shape morphing of elastic shells.

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

Makarov, Nikolay S.; Lin, Qianglu; Pietryga, Jeffrey M.

One source of efficiency losses in photovoltaic cells is their transparency toward solar photons with energies below the band gap of the absorbing layer. This loss can be reduced using a process of up-conversion whereby two or more sub-band-gap photons generate a single above-gap exciton. Traditional approaches to up-conversion, such as nonlinear two-photon absorption (2PA) or triplet fusion, suffer from low efficiency at solar light intensities, a narrow absorption bandwidth, nonoptimal absorption energies, and difficulties for implementing in practical devices. We show that these deficiencies can be alleviated using the effect of Auger up-conversion in thick-shell PbSe/CdSe quantum dots. Thismore » process relies on Auger recombination whereby two low-energy, core-based excitons are converted into a single higher-energy, shell-based exciton. When compared to their monocomponent counterparts, the tailored PbSe/CdSe heterostructures feature enhanced absorption cross-sections, a higher efficiency of the “productive” Auger pathway involving re-excitation of a hole, and longer lifetimes of both core- and shell-localized excitons. These features lead to effective up-conversion cross-sections that are more than 6 orders of magnitude higher than for standard nonlinear 2PA, which allows for efficient up-conversion of continuous wave infrared light at intensities as low as a few watts per square centimeter.« less

Preparation and Characterization of Pyrotechnics Binder-Coated Nano-Aluminum Composite Particles

NASA Astrophysics Data System (ADS)

Ye, Mingquan; Zhang, Shuting; Liu, Songsong; Han, Aijun; Chen, Xin

2017-07-01

The aim of this article is to protect the activity of nano-aluminum (Al) particles in solid rocket propellants and pyrotechnics. The morphology, structure, active aluminum content, and thermal and catalytic properties of the coated samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetry-differential scanning calorimetry (TG-DSC), and oxidation-reduction titration methods. The results indicated that nano-Al particles could be effectively coated with phenolic resin (PF), fluororubber (Viton B), and shellac through a solvent/nonsolvent method. The energetic composite particles have core-shell structures and the thickness of the coating film is about 5-15 nm. Analysis of the active Al content revealed that Viton B coating had a much better protective effect. The TG-DSC results showed that the energy amount and energy release rate of PF-, Viton B-, and shellac-coated Al particles were larger than those of the raw nano-Al particles. The catalytic effects of coated Al particles on the thermal decomposition of ammonium perchlorate (AP) were better than those of raw nano-Al particles, and the effect of shellac-coated Al particles was significantly better than that of Viton B-coated Al particles.

Quantum funneling in blended multi-band gap core/shell colloidal quantum dot solar cells

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

Neo, Darren C. J.; Assender, Hazel E.; Watt, Andrew A. R., E-mail: Andrew.watt@materials.ox.ac.uk

2015-09-07

Multi-band gap heterojunction solar cells fabricated from a blend of 1.2 eV and 1.4 eV PbS colloidal quantum dots (CQDs) show poor device performance due to non-radiative recombination. To overcome this, a CdS shell is epitaxially formed around the PbS core using cation exchange. From steady state and transient photoluminescence measurements, we understand the nature of charge transfer between these quantum dots. Photoluminescence decay lifetimes are much longer in the PbS/CdS core/shell blend compared to PbS only, explained by a reduction in non-radiative recombination resulting from CdS surface passivation. PbS/CdS heterojunction devices sustain a higher open-circuit voltage and lower reverse saturation currentmore » as compared to PbS-only devices, implying lower recombination rates. Further device performance enhancement is attained by modifying the composition profile of the CQD species in the absorbing layer resulting in a three dimensional quantum cascade structure.« less

B(E2)↑ Measurements for Radioactive Neutron-Rich Ge Isotopes: Reaching the N=50 Closed Shell

NASA Astrophysics Data System (ADS)

Padilla-Rodal, E.; Galindo-Uribarri, A.; Baktash, C.; Batchelder, J. C.; Beene, J. R.; Bijker, R.; Brown, B. A.; Castaños, O.; Fuentes, B.; del Campo, J. Gomez; Hausladen, P. A.; Larochelle, Y.; Lisetskiy, A. F.; Mueller, P. E.; Radford, D. C.; Stracener, D. W.; Urrego, J. P.; Varner, R. L.; Yu, C.-H.

2005-03-01

The B(E2;0+1→2+1) values for the radioactive neutron-rich germanium isotopes 78,80Ge and the closed neutron shell nucleus 82Ge were measured at the HRIBF using Coulomb excitation in inverse kinematics. These data allow a study of the systematic trend between the subshell closures at N=40 and 50. The B(E2) behavior approaching N=50 is similar to the trend observed for heavier isotopic chains. A comparison of the experimental results with a shell model calculation demonstrates persistence of the N=50 shell gap and a strong sensitivity of the B(E2) values to the effective interaction.

Mother-Youth Acculturation Gaps and Health-Risking/Emotional Problems among Latin-American Adolescents.

PubMed

Wiesner, Margit; Arbona, Consuelo; Capaldi, Deborah M; Kim, Hyoun K; Kaplan, Charles D

2015-07-20

Second-generation Latin-American adolescents tend to show higher levels of various health-risking behaviors and emotional problems than first-generation Latin-American adolescents. This cross-sectional study of 40 mother-adolescent dyads examined the association of mother-youth acculturation gaps to youth adjustment problems. Intergenerational acculturation gaps were assessed as a bidimensional self-report component and a novel observational measurement component. The Latin-American adolescents were predominantly second-generation of Mexican descent (M age = 13.42 years, SD = 0.55). Most of the mothers were born in Mexico (M age = 39.18 years, SD = 5.17). Data were collected from mothers, adolescents, and coders, using questionnaires, structured interviews, and videotaped mother-youth interaction tasks. Findings revealed generally weak support for the acculturation gap-distress hypothesis. In addition, stronger relative adherence to their heritage culture by the adolescents was significantly (p < .05, ES = 0.15) related to less engagement in early health-risking sexual behaviors, possibly reflecting selective acculturation processes. Mother-youth acculturation gaps in orientation to the heritage culture were the most salient dimension, changing the focus on the original formulation of the acculturation gap-distress hypothesis.

Lithostratigraphy, biostratigraphy and chemostratigraphy of Upper Cretaceous and Paleogene sediments from southern Tanzania: Tanzania Drilling Project Sites 27-35

NASA Astrophysics Data System (ADS)

Jimènez Berrocoso, Àlvaro; Huber, Brian T.; MacLeod, Kenneth G.; Petrizzo, Maria Rose; Lees, Jacqueline A.; Wendler, Ines; Coxall, Helen; Mweneinda, Amina K.; Falzoni, Francesca; Birch, Heather; Singano, Joyce M.; Haynes, Shannon; Cotton, Laura; Wendler, Jens; Bown, Paul R.; Robinson, Stuart A.; Gould, Jeremy

2012-07-01

The 2008 Tanzania Drilling Project (TDP) expedition recovered common planktonic foraminifera (PF), calcareous nannofossils (CN) and calcareous dinoflagellates with extraordinary shell preservation at multiple Cenomanian-Campanian sites that will be used for paleoclimatic, paleoceanographic, and biostratigraphic studies. New cores confirm the existence of a more expanded and continuous Upper Cretaceous sequence than had previously been documented in the Lindi and Kilwa regions of southeastern coastal Tanzania. This TDP expedition cored 684.02 m at eight Upper Cretaceous sites (TDP Sites 28-35) and a thin Paleocene section (TDP Site 27). TDP Sites 29, 30, 31 and 34 together span the lowermost Turonian to Coniacian (PF Whiteinella archaeocretacea to Dicarinella concavata Zones and CN Zones UC6a-9b), with TDP Site 31 being the most biostratigraphically complete Turonian section found during TDP drilling. A discontinuous section from the Santonian-upper Campanian (PF D. asymetrica to Radotruncana calcarata Zones and CN Zones UC12-16) was collectively recovered at TDP Sites 28, 32 and 35, while thin sequences of the lower Cenomanian (PF Thalmanninella globotruncanoides Zone and CN subzones UC3a-b) and middle Paleocene (Selandian; PF Zone P3a and CN Zone NP5) were cored in TDP Sites 33 and 27, respectively. Records of δ13Corg and δ13Ccarb from bulk sediments generated for all the Cretaceous sites show largely stable values through the sections. Only a few parallel δ13Corg and δ13Ccarb shifts have been found and they are interpreted to reflect local processes. The δ18Ocarb record, however, is consistent with Late Cretaceous cooling trends from the Turonian into the Campanian. Lithologies of these sites include thick intervals of claystones and siltstones with locally abundant, finely-laminated fabrics, irregular occurrences of thin sandstone layers, and sporadic bioclastic debris (e.g., inoceramids, ammonites). Minor lithologies represent much thinner units of up to medium-grained, massive sandstones. The %CaCO3 (∼5-40%) and %Corg (∼0.1-2%) are variable, with the highest %CaCO3 in the lower Campanian and the highest %Corg in the Turonian. Lithofacies analysis suggests that deposition of these sediments occurred in outer shelf-upper slope, a setting that agrees well with inferences from benthic foraminifera and calcareous dinoflagellates.

Post-polymerization C-H Borylation of Donor-Acceptor Materials Gives Highly Efficient Solid State Near-Infrared Emitters for Near-IR-OLEDs and Effective Biological Imaging.

PubMed

Crossley, Daniel L; Urbano, Laura; Neumann, Robert; Bourke, Struan; Jones, Jennifer; Dailey, Lea Ann; Green, Mark; Humphries, Martin J; King, Simon M; Turner, Michael L; Ingleson, Michael J

2017-08-30

Post-polymerization modification of the donor-acceptor polymer, poly(9,9-dioctylfluorene-alt-benzothiadiazole), PF8-BT, by electrophilic C-H borylation is a simple method to introduce controllable quantities of near-infrared (near-IR) emitting chromophore units into the backbone of a conjugated polymer. The highly stable borylated unit possesses a significantly lower LUMO energy than the pristine polymer resulting in a reduction in the band gap of the polymer by up to 0.63 eV and a red shift in emission of more than 150 nm. Extensively borylated polymers absorb strongly in the deep red/near-IR and are highly emissive in the near-IR region of the spectrum in solution and solid state. Photoluminescence quantum yield (PLQY) values are extremely high in the solid state for materials with emission maxima ≥ 700 nm with PLQY values of 44% at 700 nm and 11% at 757 nm for PF8-BT with different borylation levels. This high brightness enables efficient solution processed near-IR emitting OLEDs to be fabricated and highly emissive borylated polymer loaded conjugated polymer nanoparticles (CPNPs) to be prepared. The latter are bright, photostable, low toxicity bioimaging agents that in phantom mouse studies show higher signal to background ratios for emission at 820 nm than the ubiquitous near-IR emissive bioimaging agent indocyanine green. This methodology represents a general approach for the post-polymerization functionalization of donor-acceptor polymers to reduce the band gap as confirmed by the C-H borylation of poly((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2c,2cc-diyl) (PF8TBT) resulting in a red shift in emission of >150 nm, thereby shifting the emission maximum to 810 nm.

A three-compartment thermometry model for the improved estimation of changes in body heat content.

PubMed

Jay, Ollie; Gariépy, Louise M; Reardon, Francis D; Webb, Paul; Ducharme, Michel B; Ramsay, Tim; Kenny, Glen P

2007-01-01

The aim of this study was to use whole body calorimetry to directly measure the change in body heat content (DeltaH(b)) during steady-state exercise and compare these values with those estimated using thermometry. The thermometry models tested were the traditional two-compartment model of "core" and "shell" temperatures, and a three-compartment model of "core," "muscle," and "shell" temperatures; with individual compartments within each model weighted for their relative influence upon DeltaH(b) by coefficients subject to a nonnegative and a sum-to-one constraint. Fifty-two participants performed 90 min of moderate-intensity exercise (40% of Vo(2 peak)) on a cycle ergometer in the Snellen air calorimeter, at regulated air temperatures of 24 degrees C or 30 degrees C and a relative humidity of either 30% or 60%. The "core" compartment was represented by temperatures measured in the esophagus (T(es)), rectum (T(re)), and aural canal (T(au)), while the "muscle" compartment was represented by regional muscle temperature measured in the vastus lateralis (T(vl)), triceps brachii (T(tb)), and upper trapezius (T(ut)). The "shell" compartment was represented by the weighted mean of 12 skin temperatures (T(sk)). The whole body calorimetry data were used to derive optimally fitting two- and three-compartment thermometry models. The traditional two-compartment model was found to be statistically biased, systematically underestimating DeltaH(b) by 15.5% (SD 31.3) at 24 degrees C and by 35.5% (SD 21.9) at 30 degrees C. The three-compartment model showed no such bias, yielding a more precise estimate of DeltaH(b) as evidenced by a mean estimation error of 1.1% (SD 29.5) at 24 degrees C and 5.4% (SD 30.0) at 30 degrees C with an adjusted R(2) of 0.48 and 0.51, respectively. It is concluded that a major source of error in the estimation of DeltaH(b) using the traditional two-compartment thermometry model is the lack of an expression independently representing the heat storage in muscle during exercise.

Mirror energy difference and the structure of loosely bound proton-rich nuclei around A =20

NASA Astrophysics Data System (ADS)

Yuan, Cenxi; Qi, Chong; Xu, Furong; Suzuki, Toshio; Otsuka, Takaharu

2014-04-01

The properties of loosely bound proton-rich nuclei around A =20 are investigated within the framework of the nuclear shell model. In these nuclei, the strength of the effective interactions involving the loosely bound proton s1/2 orbit is significantly reduced in comparison with that of those in their mirror nuclei. We evaluate the reduction of the effective interaction by calculating the monopole-based-universal interaction (VMU) in the Woods-Saxon basis. The shell-model Hamiltonian in the sd shell, such as USD, can thus be modified to reproduce the binding energies and energy levels of the weakly bound proton-rich nuclei around A =20. The effect of the reduction of the effective interaction on the structure and decay properties of these nuclei is also discussed.

Cone Photoreceptor Irregularity on Adaptive Optics Scanning Laser Ophthalmoscopy Correlates With Severity of Diabetic Retinopathy and Macular Edema

PubMed Central

Lammer, Jan; Prager, Sonja G.; Cheney, Michael C.; Ahmed, Amel; Radwan, Salma H.; Burns, Stephen A.; Silva, Paolo S.; Sun, Jennifer K.

2016-01-01

Purpose To determine whether cone density, spacing, or regularity in eyes with and without diabetes (DM) as assessed by high-resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) correlates with presence of diabetes, diabetic retinopathy (DR) severity, or presence of diabetic macular edema (DME). Methods Participants with type 1 or 2 DM and healthy controls underwent AOSLO imaging of four macular regions. Cone assessment was performed by independent graders for cone density, packing factor (PF), nearest neighbor distance (NND), and Voronoi tile area (VTA). Regularity indices (mean/SD) of NND (RI-NND) and VTA (RI-VTA) were calculated. Results Fifty-three eyes (53 subjects) were assessed. Mean ± SD age was 44 ± 12 years; 81% had DM (duration: 22 ± 13 years; glycated hemoglobin [HbA1c]: 8.0 ± 1.7%; DM type 1: 72%). No significant relationship was found between DM, HbA1c, or DR severity and cone density or spacing parameters. However, decreased regularity of cone arrangement in the macular quadrants was correlated with presence of DM (RI-NND: P = 0.04; RI-VTA: P = 0.04), increasing DR severity (RI-NND: P = 0.04), and presence of DME (RI-VTA: P = 0.04). Eyes with DME were associated with decreased density (P = 0.04), PF (P = 0.03), and RI-VTA (0.04). Conclusions Although absolute cone density and spacing don't appear to change substantially in DM, decreased regularity of the cone arrangement is consistently associated with the presence of DM, increasing DR severity, and DME. Future AOSLO evaluation of cone regularity is warranted to determine whether these changes are correlated with, or predict, anatomic or functional deficits in patients with DM. PMID:27926754

Cone Photoreceptor Irregularity on Adaptive Optics Scanning Laser Ophthalmoscopy Correlates With Severity of Diabetic Retinopathy and Macular Edema.

PubMed

Lammer, Jan; Prager, Sonja G; Cheney, Michael C; Ahmed, Amel; Radwan, Salma H; Burns, Stephen A; Silva, Paolo S; Sun, Jennifer K

2016-12-01

To determine whether cone density, spacing, or regularity in eyes with and without diabetes (DM) as assessed by high-resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) correlates with presence of diabetes, diabetic retinopathy (DR) severity, or presence of diabetic macular edema (DME). Participants with type 1 or 2 DM and healthy controls underwent AOSLO imaging of four macular regions. Cone assessment was performed by independent graders for cone density, packing factor (PF), nearest neighbor distance (NND), and Voronoi tile area (VTA). Regularity indices (mean/SD) of NND (RI-NND) and VTA (RI-VTA) were calculated. Fifty-three eyes (53 subjects) were assessed. Mean ± SD age was 44 ± 12 years; 81% had DM (duration: 22 ± 13 years; glycated hemoglobin [HbA1c]: 8.0 ± 1.7%; DM type 1: 72%). No significant relationship was found between DM, HbA1c, or DR severity and cone density or spacing parameters. However, decreased regularity of cone arrangement in the macular quadrants was correlated with presence of DM (RI-NND: P = 0.04; RI-VTA: P = 0.04), increasing DR severity (RI-NND: P = 0.04), and presence of DME (RI-VTA: P = 0.04). Eyes with DME were associated with decreased density (P = 0.04), PF (P = 0.03), and RI-VTA (0.04). Although absolute cone density and spacing don't appear to change substantially in DM, decreased regularity of the cone arrangement is consistently associated with the presence of DM, increasing DR severity, and DME. Future AOSLO evaluation of cone regularity is warranted to determine whether these changes are correlated with, or predict, anatomic or functional deficits in patients with DM.

Direct Correlation of Excitonics with Efficiency in a Core-Shell Quantum Dot Solar Cell.

PubMed

Dana, Jayanta; Maiti, Sourav; Tripathi, Vaidehi S; Ghosh, Hirendra N

2018-02-16

Shell thickness dependent band-gap engineering of quasi type II core-shell material with higher carrier cooling time, lower interfacial defect states, and longer charge carrier recombination time can be a promising candidate for both photocatalysis and solar cell. In the present investigation, colloidal CdSe@CdS core-shells with different shell thickness (2, 4 and 6 monolayer CdS) were synthesized through hot injection method and have been characterized by high resolution transmission electron microscope (HRTEM) followed by steady state absorption and luminescence techniques. Ultrafast transient absorption (TA) studies suggest longer carrier cooling, lower interfacial surface states, and slower carrier recombination time in CdSe@CdS core-shell with increasing shell thickness. By TA spectroscopy, the role of CdS shell in power conversion efficiency (PCE) has been explained in detail. The measured PCE was found to initially increase and then decrease with increasing shell thickness. Shell thickness has been optimized to maximize the efficiency after correlating the shell controlled carrier cooling and recombination with PCE values and a maximum PCE of 3.88 % was obtained with 4 monolayers of CdS shell, which is found to be 57 % higher than compared to bare CdSe QDs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of a pharmacotherapy follow-up in community pharmacies on type 2 diabetes patients in Brazil.

PubMed

Correr, Cassyano Januário; Melchiors, Ana Carolina; Fernandez-Llimos, Fernando; Pontarolo, Roberto

2011-04-01

To evaluate the effects of pharmacotherapy follow-up (PF) on metabolic control and clinical outcomes in type 2 diabetic patients. Six community pharmacies (4 intervention and 2 control) in the Curitiba metropolitan region (Brazil). Glycosylated Haemoglobin A1 (HbA1) and fasting capillary glycaemia. We conducted a 12-month controlled trial involving a total of 161 patients in six community pharmacies between July 2004 and March 2006. Pharmacotherapy follow-up was applied only to patients in the intervention group. Of the 161 patients enrolled, 96 completed the study (50 intervention and 46 control). The administration of 574 consultations with the intervention group patients led to 119 negative clinical outcomes (2.3/patient [SD = 1.6]). The majority of detected problems were related to the ineffectiveness of pharmacotherapy (68.1%). Relative to the control group, the intervention group exhibited greater glycosylated haemoglobin (HbA1) reduction (-2.2% [95%CI -2.8%:-1.6%] vs. -0.3 [95% CI -0.8:0.2]; P < 0.001) and greater fasting capillary glycaemia reduction (-20.1 mg/dl [95% CI -31.9 mg/dl:-8.3 mg/dl] vs. 4.3 mg/dl [95% CI -13.4 mg/dl:22.2 mg/dl]; P = 0.022). These differences persisted after adjustment for baseline values. There were no significant differences in any other clinical measures between the groups. There were also no significant changes in the number of medications and treatment regimens between groups, with the exception of the percentage of patients undergoing lipid lowering treatment, which increased in the intervention group from 16% to 24% (P = 0.018). The initial medication regimen complexity index (MRCI) in the intervention group was 15.5 (SD = 7.8, range 4-40.5), and it decreased by 1.2 units (SD = 5.9) after 12 months (P = 0.149). PF of type 2 diabetic patients in community pharmacies can improve the glycaemia control of patients through optimisation of medication profiles without significant changes in either the number of drugs used or the regimen complexity.

High performance of histidine-rich protein 2 based rapid diagnostic tests in French Guiana are explained by the absence of pfhrp2 gene deletion in P. falciparum.

PubMed

Trouvay, Mélanie; Palazon, Georges; Berger, Franck; Volney, Béatrice; Blanchet, Denis; Faway, Emilie; Donato, Damien; Legrand, Eric; Carme, Bernard; Musset, Lise

2013-01-01

Care for malaria patients in endemic areas has been improved through the increasing use of Rapid Diagnostic Tests (RDTs). Most RDTs target the histidine-rich protein-2 antigen (PfHRP2) to detect P. falciparum, as it is abundant and shows great heat stability. However, their use in South America has been widely questioned following a recent publication that pinpoints the high prevalence of Peruvian field isolates lacking the gene encoding this protein. In the remote rural health centers of French Guiana, RDTs are the main diagnosis tools. Therefore, a study of PfHRP2 RDT performances and pfhrp2 genotyping was conducted to determine whether a replacement of the current pLDH-based kit could be considered. The performance study compared the SD Malaria Ag test P.f/Pan® kit with the current gold standard diagnosis by microscopy. The prevalence of pfhrp2 and pfhrp3 deletions were evaluated from 221 P. falciparum isolates collected between 2009 and 2011 in French Guiana. Between January 2010 and August 2011, 960 suspected cases of malaria were analyzed using microscopy and RDTs. The sensitivity of the SD Malaria Ag test P.f/Pan® for detection of P. falciparum was 96.8% (95% CI: 90.9-99.3), and 86.0% (95% CI: 78.9-91.5) for the detection of P. vivax. No isolates (95% CI: 0-4.5) lacking either exon of the pfhrp2 gene were identified among the 221 P. falciparum isolates analyzed, but 7.4% (95% CI: 2.8-15.4) lacked the exon 2 part of the pfhrp3 gene. Field isolates lacking either exon of the pfhrp2 gene are absent in this western part of South America. Despite its sensibility to detect P. vivax, the SD Malaria Ag test P.f/Pan® kit is a satisfying alternative to microscopy in remote health centers, where it is difficult to provide highly skilled microscopists and to maintain the necessary equipment.

Performance of an ultra-sensitive Plasmodium falciparum HRP2-based rapid diagnostic test with recombinant HRP2, culture parasites, and archived whole blood samples.

PubMed

Das, Smita; Peck, Roger B; Barney, Rebecca; Jang, Ihn Kyung; Kahn, Maria; Zhu, Meilin; Domingo, Gonzalo J

2018-03-17

As malaria endemic countries shift from control to elimination, the proportion of low density Plasmodium falciparum infections increases. Current field diagnostic tools, such as microscopy and rapid diagnostic tests (RDT), with detection limits of approximately 100-200 parasites/µL (p/µL) and 800-1000 pg/mL histidine-rich protein 2 (HRP2), respectively, are unable to detect these infections. A novel ultra-sensitive HRP2-based Alere™ Malaria Ag P.f RDT (uRDT) was evaluated in laboratory conditions to define the test's performance against recombinant HRP2 and native cultured parasites. The uRDT detected dilutions of P. falciparum recombinant GST-W2 and FliS-W2, as well as cultured W2 and ITG, diluted in whole blood down to 10-40 pg/mL HRP2, depending on the protein tested. uRDT specificity was 100% against 123 archived frozen whole blood samples. Rapid test cross-reactivity with HRP3 was investigated using pfhrp2 gene deletion strains D10 and Dd2, pfhrp3 gene deletion strain HB3, and controls pfhrp2 and pfhrp3 double deletion strain 3BD5 and pfhrp2 and pfhrp3 competent strain ITG. The commercial Standard Diagnostics, Inc. BIOLINE Malaria Ag P.f RDT (SD-RDT) and uRDT detected pfhrp2 positive strains down to 49 and 3.13 p/µL, respectively. The pfhrp2 deletion strains were detected down to 98 p/µL by both tests. The performance of the uRDT was variable depending on the protein, but overall showed a greater than 10-fold improvement over the SD-RDT. The uRDT also exhibited excellent specificity and showed the same cross-reactivity with HRP3 as the SD-RDT. Together, the results support the uRDT as a more sensitive HRP2 test that could be a potentially effective tool in elimination campaigns. Further clinical evaluations for this purpose are merited.

An algebraic cluster model based on the harmonic oscillator basis

NASA Technical Reports Server (NTRS)

Levai, Geza; Cseh, J.

1995-01-01

We discuss the semimicroscopic algebraic cluster model introduced recently, in which the internal structure of the nuclear clusters is described by the harmonic oscillator shell model, while their relative motion is accounted for by the Vibron model. The algebraic formulation of the model makes extensive use of techniques associated with harmonic oscillators and their symmetry group, SU(3). The model is applied to some cluster systems and is found to reproduce important characteristics of nuclei in the sd-shell region. An approximate SU(3) dynamical symmetry is also found to hold for the C-12 + C-12 system.

Development of a Novel Targeted RNAi Delivery Technology in Therapies for Metabolic Diseases

DTIC Science & Technology

2016-10-01

Kupffer cells and macrophages as demonstrated in our earlier studies, for targeted delivery of the sdRNA to these phagocytes in liver as originally...conjugation to glucan shell while preserving targeting specificity to phagocytic cells observed with our existing GeRP formulations. Small

Influence of dimensionality and interface type on optical and electronic properties of CdS/ZnS core-shell nanocrystals—A first-principles study

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

Kocevski, V., E-mail: vancho.vk@gmail.com, E-mail: vancho.kocevski@physics.uu.se; Eriksson, O.; Gerard, C.

2015-10-28

Semiconducting nanocrystals (NCs) have become one of the leading materials in a variety of applications, mainly due to their size tunable band gap and high intensity emission. Their photoluminescence (PL) properties can be notably improved by capping the nanocrystals with a shell of another semiconductor, making core-shell structures. We focus our study on the CdS/ZnS core-shell nanocrystals that are closely related to extensively studied CdSe/CdS NCs, albeit exhibiting rather different photoluminescence properties. We employ density functional theory to investigate the changes in the electronic and optical properties of these nanocrystals with size, core/shell ratio, and interface structure between the coremore » and the shell. We have found that both the lowest unoccupied eigenstate (LUES) and the highest occupied eigenstate (HOES) wavefunction (WF) are localized in the core of the NCs, with the distribution of the LUES WF being more sensitive to the size and the core/shell ratio. We show that the radiative lifetimes are increasing, and the Coulomb interaction energies decrease with increasing NC size. Furthermore, we investigated the electronic and optical properties of the NCs with different interfaces between the core and the shell and different core types. We find that the different interfaces and core types have rather small influence on the band gaps and the absorption indexes, as well as on the confinement of the HOES and LUES WFs. Also the radiative lifetimes are found to be only slightly influenced by the different structural models. In addition, we compare these results with the previous results for CdSe/CdS NCs, reflecting the different PL properties of these two types of NCs. We argue that the difference in their Coulomb interaction energies is one of the main reasons for their distinct PL properties.« less

Practicing DSAM in aberrant domain: use of multi-disciplinary techniques

NASA Astrophysics Data System (ADS)

Das, S.; Samanta, S.; Bhattacharjee, R.; Raut, R.; Ghugre, S. S.; Sinha, A. K.; Garg, U.; Chakrabarti, R.; Mukhopadhyay, S.; Madhavan, N.; Muralithar, S.; Singh, R. P.; Sethi, J.; Saha, S.; Palit, R.

2016-10-01

Measurement of level lifetime of nuclear states is of relevance in nuclear structure research as it provides us with an unique probe into the underlying microscopic structure of these states. Of the several experimental techniques for lifetime measurements, the Doppler Shift Attenuation Method (DSAM) is the one adopted for measuring lifetimes typically in the range of few tens of fs to few ps. The technique is based on the analysis of the observed Doppler affected gamma rays emitted by the recoils in flight. The crucial component in the related analysis is the simulation of the stopping process, of the residues of interest, in the target and the backing media. This requires calculation of the corresponding stopping powers and the same has been identified as one of the principal uncertainties in the extracted lifetime in DSAM. Traditionally the method is pursued with a thin target, for production of nuclei of interest, on a thick elemental backing wherein stopping process is perceived to occur. The present work in light of it's objectives uses a setup which is in sharp variance with the conventional scenario, such as the use of a thick molecular target, which contributes both to the production of the residues as well as their subsequent slowing down. This demanded extensive developments in the analysis procedure particularly in the domain of simulating the stopping process with due incorporation of the nuances of nuclear reaction kinematics besides subjecting the molecular medium to a detailed structural characterization, routinely carried out in the domain of material science. These developments have been used to extract the level lifetimes of nuclei at the interface of the sd & pf shells such as 26Mg, 29Si, and 32P.

Persistence of the Z =28 Shell Gap Around 78Ni: First Spectroscopy of 79Cu

NASA Astrophysics Data System (ADS)

Olivier, L.; Franchoo, S.; Niikura, M.; Vajta, Z.; Sohler, D.; Doornenbal, P.; Obertelli, A.; Tsunoda, Y.; Otsuka, T.; Authelet, G.; Baba, H.; Calvet, D.; Château, F.; Corsi, A.; Delbart, A.; Gheller, J.-M.; Gillibert, A.; Isobe, T.; Lapoux, V.; Matsushita, M.; Momiyama, S.; Motobayashi, T.; Otsu, H.; Péron, C.; Peyaud, A.; Pollacco, E. C.; Roussé, J.-Y.; Sakurai, H.; Santamaria, C.; Sasano, M.; Shiga, Y.; Takeuchi, S.; Taniuchi, R.; Uesaka, T.; Wang, H.; Yoneda, K.; Browne, F.; Chung, L. X.; Dombradi, Z.; Flavigny, F.; Giacoppo, F.; Gottardo, A.; Hadyńska-Klek, K.; Korkulu, Z.; Koyama, S.; Kubota, Y.; Lee, J.; Lettmann, M.; Louchart, C.; Lozeva, R.; Matsui, K.; Miyazaki, T.; Nishimura, S.; Ogata, K.; Ota, S.; Patel, Z.; Sahin, E.; Shand, C.; Söderström, P.-A.; Stefan, I.; Steppenbeck, D.; Sumikama, T.; Suzuki, D.; Werner, V.; Wu, J.; Xu, Z.

2017-11-01

In-beam γ -ray spectroscopy of 79Cu is performed at the Radioactive Isotope Beam Factory of RIKEN. The nucleus of interest is produced through proton knockout from a 80Zn beam at 270 MeV /nucleon . The level scheme up to 4.6 MeV is established for the first time and the results are compared to Monte Carlo shell-model calculations. We do not observe significant knockout feeding to the excited states below 2.2 MeV, which indicates that the Z =28 gap at N =50 remains large. The results show that the 79Cu nucleus can be described in terms of a valence proton outside a 78Ni core, implying the magic character of the latter.

Cross-sectional aspect ratio modulated electronic properties in Si/Ge core/shell nanowires

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

Liu, Nuo; Lu, Ning; Yao, Yong-Xin

2013-02-28

Electronic structures of (4, n) and (m, 4) (the NW has m layers parallel to the {1 1 1} facet and n layers parallel to {1 1 0}) Si/Ge core/shell nanowires (NWs) along the [1 1 2] direction with cross-sectional aspect ratio (m/n) from 0.36 to 2.25 are studied by first-principles calculations. An indirect to direct band gap transition is observed as m/n decreases, and the critical values of m/n and diameter for the transition are also estimated. The size of the band gap also depends on the aspect ratio. These results suggest that m/n plays an important role inmore » modulating the electronic properties of the NWs.« less

Highly luminescent InP/GaP/ZnS nanocrystals and their application to white light-emitting diodes.

PubMed

Kim, Sungwoo; Kim, Taehoon; Kang, Meejae; Kwak, Seong Kwon; Yoo, Tae Wook; Park, Lee Soon; Yang, Ilseung; Hwang, Sunjin; Lee, Jung Eun; Kim, Seong Keun; Kim, Sang-Wook

2012-02-29

Highly stable and luminescent InP/GaP/ZnS QDs with a maximum quantum yield of 85% were synthesized by in situ method. The GaP shell rendered passivation of the surface and removed the traps. TCSPC data showed an evidence for the GaP shell. InP/GaP/ZnS QDs show better stability than InP/ZnS. We studied the optical properties of white QD-LEDs corresponding to various QD concentrations. Among various concentrations, the white QD-LEDs with 0.5 mL of QDs exhibited a luminous efficiency of 54.71 lm/W, Ra of 80.56, and CCT of 7864 K. © 2012 American Chemical Society

Amplified Photon Upconversion by Photonic Shell of Cholesteric Liquid Crystals.

PubMed

Kang, Ji-Hwan; Kim, Shin-Hyun; Fernandez-Nieves, Alberto; Reichmanis, Elsa

2017-04-26

As an effective platform to exploit triplet-triplet-annihilation-based photon upconversion (TTA-UC), microcapsules composed of a fluidic UC core and photonic shell are microfluidically prepared using a triple emulsion as the template. The photonic shell consists of cholesteric liquid crystals (CLCs) with a periodic helical structure, exhibiting a photonic band gap. Combined with planar anchoring at the boundaries, the shell serves as a resonance cavity for TTA-UC emission and enables spectral tuning of the UC under low-power-density excitation. The CLC shell can be stabilized by introducing a polymerizable mesogen in the LC host. Because of the microcapsule spherical symmetry, spontaneous emission of the delayed fluorescence is omnidirectionally amplified at the edge of the stop band. These results demonstrate the range of opportunities provided by TTA-UC systems for the future design of low-threshold photonic devices.

The Origin of Hot Subluminous Horizontal-Branch Stars in (omega) Centauri and NGC 2808

NASA Technical Reports Server (NTRS)

Sweigart, Allen V.; Brown, Thomas M.; Lanz, Thierry; Landsman, Wayne B.; Hubeny, Ivan

2001-01-01

Hot subluminous stars lying up to 0.7 mag below the extreme horizontal branch (EHB) are found in the ultraviolet (UV) color magnitude diagrams of both (omega) Cen and NGC 2808. In order to explore the evolutionary status of these subluminous stars, we have evolved a set of low-mass stars continuously from the main sequence through the helium-core flash to the HB (horizontal branch) for a wide range in the mass loss along the red-giant branch (RGB). Stars with the largest mass loss evolve off the RGB to high effective temperatures before igniting helium in their cores. Our results indicate that the subluminous EHB stars, as well as the gap within the EHB of NGC 2808, can be explained if these stars undergo a late helium-core flash while descending the white-dwarf cooling curve. Under these conditions the convection zone produced by the helium flash will penetrate into the stellar envelope, thereby mixing most, if not all, of the envelope hydrogen into the hot helium-burning interior, where it is rapidly consumed. This phenomenon is analogous to the 'born-again' scenario for producing hydrogen-deficient stars following a very late helium-shell flash. This 'flash mixing' of the stellar envelope greatly enhances the envelope helium and carbon abundances and, as a result, leads to a discontinuous jump in the HB effective temperature. We argue that the EHB gap in NGC 2808 is associated with this theoretically predicted dichotomy in the HB morphology. Using new helium- and carbon-rich stellar atmospheres, we show that these changes in the envelope abundances of the flash-mixed stars will suppress the UV flux by the amount needed to explain the hot subluminous EHB stars in (omega) Cen and NGC 2808. Moreover, we demonstrate that models without flash mixing lie, at most, only approximately 0.1 mag below the EHB, and hence fail to explain the observations. Flash mixing may also provide a new evolutionary channel for producing the high gravity, helium-rich sdO and sdB stars.

Structure of neutron-rich nuclei around the N = 50 shell-gap closure

NASA Astrophysics Data System (ADS)

Faul, T.; Duchêne, G.; Thomas, J.-C.; Nowacki, F.; Huyse, M.; Van Duppen, P.

2010-04-01

The structure of neutron-rich nuclei in the vicinity of 78Ni have been investigated via the β-decay of 71,73,75Cu isotopes (ISOLDE, CERN). Experimental results have been compared with shell-model calculations performed with the ANTOINE code using a large (2p3/21f5/22p1/21g9/2) valence space and a 56/28Ni28 core.

Self consistent field theory of virus assembly

NASA Astrophysics Data System (ADS)

Li, Siyu; Orland, Henri; Zandi, Roya

2018-04-01

The ground state dominance approximation (GSDA) has been extensively used to study the assembly of viral shells. In this work we employ the self-consistent field theory (SCFT) to investigate the adsorption of RNA onto positively charged spherical viral shells and examine the conditions when GSDA does not apply and SCFT has to be used to obtain a reliable solution. We find that there are two regimes in which GSDA does work. First, when the genomic RNA length is long enough compared to the capsid radius, and second, when the interaction between the genome and capsid is so strong that the genome is basically localized next to the wall. We find that for the case in which RNA is more or less distributed uniformly in the shell, regardless of the length of RNA, GSDA is not a good approximation. We observe that as the polymer-shell interaction becomes stronger, the energy gap between the ground state and first excited state increases and thus GSDA becomes a better approximation. We also present our results corresponding to the genome persistence length obtained through the tangent-tangent correlation length and show that it is zero in case of GSDA but is equal to the inverse of the energy gap when using SCFT.

Free energy force field (FEFF) 3D-QSAR analysis of a set of Plasmodium falciparum dihydrofolate reductase inhibitors

NASA Astrophysics Data System (ADS)

Santos-Filho, Osvaldo A.; Mishra, Rama K.; Hopfinger, A. J.

2001-09-01

Free energy force field (FEFF) 3D-QSAR analysis was used to construct ligand-receptor binding models for a set of 18 structurally diverse antifolates including pyrimethamine, cycloguanil, methotrexate, aminopterin and trimethoprim, and 13 pyrrolo[2,3-d]pyrimidines. The molecular target (`receptor') used was a 3D-homology model of a specific mutant type of Plasmodium falciparum (Pf) dihydrofolate reductase (DHFR). The dependent variable of the 3D-QSAR models is the IC50 inhibition constant for the specific mutant type of PfDHFR. The independent variables of the 3D-QSAR models (the descriptors) are scaled energy terms of a modified first-generation AMBER force field combined with a hydration shell aqueous solvation model and a collection of 2D-QSAR descriptors often used in QSAR studies. Multiple temperature molecular dynamics simulation (MDS) and the genetic function approximation (GFA) were employed using partial least square (PLS) and multidimensional linear regressions as the fitting functions to develop FEFF 3D-QSAR models for the binding process. The significant FEFF energy terms in the best 3D-QSAR models include energy contributions of the direct ligand-receptor interaction. Some changes in conformational energy terms of the ligand due to binding to the enzyme are also found to be important descriptors. The FEFF 3D-QSAR models indicate some structural features perhaps relevant to the mechanism of resistance of the PfDHFR to current antimalarials. The FEFF 3D-QSAR models are also compared to receptor-independent (RI) 4D-QSAR models developed in an earlier study and subsequently refined using recently developed generalized alignment rules.

Auger Up-Conversion of Low-Intensity Infrared Light in Engineered Quantum Dots

DOE PAGES

Makarov, Nikolay S.; Lin, Qianglu; Pietryga, Jeffrey M.; ...

2016-11-29

One source of efficiency losses in photovoltaic cells is their transparency toward solar photons with energies below the band gap of the absorbing layer. This loss can be reduced using a process of up-conversion whereby two or more sub-band-gap photons generate a single above-gap exciton. Traditional approaches to up-conversion, such as nonlinear two-photon absorption (2PA) or triplet fusion, suffer from low efficiency at solar light intensities, a narrow absorption bandwidth, nonoptimal absorption energies, and difficulties for implementing in practical devices. We show that these deficiencies can be alleviated using the effect of Auger up-conversion in thick-shell PbSe/CdSe quantum dots. Thismore » process relies on Auger recombination whereby two low-energy, core-based excitons are converted into a single higher-energy, shell-based exciton. When compared to their monocomponent counterparts, the tailored PbSe/CdSe heterostructures feature enhanced absorption cross-sections, a higher efficiency of the “productive” Auger pathway involving re-excitation of a hole, and longer lifetimes of both core- and shell-localized excitons. These features lead to effective up-conversion cross-sections that are more than 6 orders of magnitude higher than for standard nonlinear 2PA, which allows for efficient up-conversion of continuous wave infrared light at intensities as low as a few watts per square centimeter.« less

X-ray Power Increase from Symmetrized Wire-Array z-Pinch Implosions on Saturn.*

NASA Astrophysics Data System (ADS)

Sanford, T. W. L.; Allshouse, G. O.; Marder, B. M.; Nash, T. J.; Mock, R. C.; Douglas, M. R.; Spielman, R. B.; Seaman, J. F.; McGurn, J. S.; Jobe, D.; Gilliland, T. L.; Vargas, M.; Struve, K. W.; Stygar, W. A.; Hammer, J. H.; Degroot, J. S.; Eddleman, J. L.; Peterson, D. L.; Whitney, K. G.; Thornhill, J. W.; Pulsifer, P. E.; Apruzese, J. P.; Mosher, D.; Maron, Y.

1996-11-01

A systematic experimental study of annular aluminum wire z-pinches on the Saturn accelerator at Sandia National Laboratories shows that, for the first time, many of the measured spatial characteristics and x-ray powers can be correlated to 1D and 2D, radiation-magneto-hydrodynamic code (RMHC) simulations when large numbers of wires are used. Calculations show that the implosion begins to transition from that of individual wire plasmas to that of a continuous plasma shell when the circumferential gap between wires in the array is reduced below 1.4 +1.3/-0.7 mm. This calculated gap coincides with the measured transition of 1.4±0.4 mm between the observed regimes of slow and rapid improvement in power output with decreasing gap. In the plasma-shell regime, x-ray power has been more than tripled over that generated in the wire-plasma regime. In the full paper, measured characteristics in the plasma-shell regime are compared with 2D, 1- and 20-mm axial length simulations of the implosion using a multi-photon-group Lagrangian RMHC^1 and a three-temperature Eulerian RMHC,^2 respectively. ^1J.H. Hammer, et al., Phys. Plasmas 3, 2063 (1996). ^2D.L. Peterson, et al., Phys. Plasmas 3, 368 (1996). Work supported by U.S. DOE Contract No. DE-AC04-94AL85000.

Treatment with PF-04449913, an oral smoothened antagonist, in patients with myeloid malignancies: a phase 1 safety and pharmacokinetics study.

PubMed

Martinelli, Giovanni; Oehler, Vivian G; Papayannidis, Cristina; Courtney, Rachel; Shaik, M Naveed; Zhang, Xiaoxi; O'Connell, Ashleigh; McLachlan, Karen R; Zheng, Xianxian; Radich, Jerald; Baccarani, Michele; Kantarjian, Hagop M; Levin, Wendy J; Cortes, Jorge E; Jamieson, Catriona

2015-08-01

Activation of the Hedgehog signalling pathway contributes to cancer progression and the development of myeloid leukaemia stem cell therapeutic resistance. We aimed to identify the maximum tolerated dose (MTD) and the recommended phase 2 dose of the selective Hedgehog antagonist PF-04449913 in myeloid malignancies. We undertook an open-label, dose-finding, standard 3+3 design phase 1 study of PF-04449913 in adult patients with acute myeloid leukaemia, chronic myeloid leukaemia, chronic myelomonocytic leukaemia, myelodysplastic syndrome, or myelofibrosis who were refractory, resistant, or intolerant to previous treatments, at three centres in the USA and one in Italy. Patients who had newly diagnosed, untreated disease were included if they were not eligible for standard treatment options or if standard treatments were not deemed appropriate. Patients received PF-04449913 once daily continuously until disease progression, unacceptable toxic effects, or patient withdrawal for up to 12 28-day cycles. Additional cycles were given if patients showed evidence of clinical benefit. The starting dose was 5 mg and was increased by 100% until the first dose-limiting toxic effect (DLT) and by 50% thereafter, in keeping with a 3+3 clinical trial statistical design. The primary endpoint was first-cycle DLTs. Secondary endpoints were safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary clinical activity. This trial is registered with ClinicalTrials.gov, number NCT00953758. Between March 24, 2010, and Sept 7, 2012, 47 patients were enrolled and included in the study: 28 with acute myeloid leukaemia, six with myelodysplastic syndrome, five with chronic myeloid leukaemia (two with chronic-phase and three with blast-phase disease), one with chronic myelomonocytic leukaemia, and seven with myelofibrosis. Patients received PF-04449913 once daily at 5 mg (n=3), 10 mg (n=3), 20 mg (n=4), 40 mg (n=4), 80 mg (n=8), 120 mg (n=3), 180 mg (n=3), 270 mg (n=5), 400 mg (n=9), and 600 mg (n=5). Two patients experienced DLTs (one each in the 80 mg and 600 mg dose groups). The MTD for PF-04449913 was established to be 400 mg once daily. Of the 47 patients enrolled, 28 (60%) experienced treatment-related adverse events, three of which were grade 4 in severity. The most common treatment-related adverse events included dysgeusia (13 [28%] patients), decreased appetite (nine [19%]), and alopecia (seven [15%]). None of the 15 deaths reported were treatment related. Pharmacokinetics seemed to be dose proportional. The mean half-life was 23·9 h (SD 14·0) in the MTD group. Some suggestion of clinical activity was noted in 23 (49%) of 47 patients with haematological malignancies. Based on these results, the recommended phase 2 dose was 200 mg or lower once daily. Based on these findings, PF-04449913 is being tested in phase 2 studies in patients with myelodysplastic syndrome, acute myeloid leukaemia, and myelofibrosis. Pfizer. Copyright © 2015 Elsevier Ltd. All rights reserved.

High performance of PbSe/PbS core/shell quantum dot heterojunction solar cells: short circuit current enhancement without the loss of open circuit voltage by shell thickness control.

PubMed

Choi, Hyekyoung; Song, Jung Hoon; Jang, Jihoon; Mai, Xuan Dung; Kim, Sungwoo; Jeong, Sohee

2015-11-07

We fabricated heterojunction solar cells with PbSe/PbS core shell quantum dots and studied the precisely controlled PbS shell thickness dependency in terms of optical properties, electronic structure, and solar cell performances. When the PbS shell thickness increases, the short circuit current density (JSC) increases from 6.4 to 11.8 mA cm(-2) and the fill factor (FF) enhances from 30 to 49% while the open circuit voltage (VOC) remains unchanged at 0.46 V even with the decreased effective band gap. We found that the Fermi level and the valence band maximum level remain unchanged in both the PbSe core and PbSe/PbS core/shell with a less than 1 nm thick PbS shell as probed via ultraviolet photoelectron spectroscopy (UPS). The PbS shell reduces their surface trap density as confirmed by relative quantum yield measurements. Consequently, PbS shell formation on the PbSe core mitigates the trade-off relationship between the open circuit voltage and the short circuit current density. Finally, under the optimized conditions, the PbSe core with a 0.9 nm thick shell yielded a power conversion efficiency of 6.5% under AM 1.5.

Core excitations across the neutron shell gap in 207Tl

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

Wilson, E.; Podolyák, Zs.; Grawe, H.

2015-05-05

The single closed-neutron-shell, one proton–hole nucleus 207Tl was populated in deep-inelastic collisions of a 208Pb beam with a 208Pb target. The yrast and near-yrast level scheme has been established up to high excitation energy, comprising an octupole phonon state and a large number of core excited states. Based on shell-model calculations, all observed single core excitations were established to arise from the breaking of the N=126 neutron core. While the shell-model calculations correctly predict the ordering of these states, their energies are compressed at high spins. It is concluded that this compression is an intrinsic feature of shell-model calculations usingmore » two-body matrix elements developed for the description of two-body states, and that multiple core excitations need to be considered in order to accurately calculate the energy spacings of the predominantly three-quasiparticle states.« less

Survival of extensively damaged endodontically treated incisors restored with different types of posts-and-core foundation restoration material.

PubMed

Lazari, Priscilla Cardoso; de Carvalho, Marco Aurélio; Del Bel Cury, Altair A; Magne, Pascal

2018-05-01

Which post-and-core combination will best improve the performance of extensively damaged endodontically treated incisors without a ferrule is still unclear. The purpose of this in vitro study was to investigate the restoration of extensively damaged endodontically treated incisors without a ferrule using glass-ceramic crowns bonded to various composite resin foundation restorations and 2 types of posts. Sixty decoronated endodontically treated bovine incisors without a ferrule were divided into 4 groups and restored with various post-and-core foundation restorations. NfPfB=no-ferrule (Nf) with glass-fiber post (Pf) and bulk-fill resin foundation restoration (B); NfPfP=no-ferrule (Nf) with glass-fiber post (Pf) and dual-polymerized composite resin core foundation restoration (P); NfPt=no-ferrule (Nf) with titanium post (Pt) and resin core foundation restoration; and NfPtB=no-ferrule (Nf) with titanium post (Pt) and bulk-fill resin core foundation restoration (B). Two additional groups from previously published data from the same authors (FPf=2mm of ferrule (F) and glass-fiber post (Pf) and composite resin core foundation restoration; and NfPf=no-ferrule (Nf) with glass-fiber post (Pf) and composite resin core foundation restoration), which were tested concomitantly and using the same experimental arrangement, were included for comparison. All teeth were prepared to receive bonded glass-ceramic crowns luted with dual-polymerized resin cement and were subjected to accelerated fatigue testing under submerged conditions at room temperature. Cyclic isometric loading was applied to the incisal edge at an angle of 30 degrees with a frequency of 5 Hz, beginning with a load of 100 N (5000 cycles). A 100-N load increase was applied every 15000 cycles. The specimens were loaded until failure or to a maximum of 1000 N (140000 cycles). The 6 groups (4 groups from the present study and 2 groups from the previously published study) were compared using the Kaplan-Meier survival analysis (log-rank post hoc test at α=.05 for pairwise comparisons). None of the tested specimen withstood all 140 000 cycles. All specimens without a ferrule were affected by an initial failure phenomenon (wide gap at the lingual margin between the core foundation restoration/crown assembly and the root). NfPfP, NfPt, and NfPtB had similar survival (29649 to 30987 mean cycles until initial failure). NfPfB outperformed NfPt and NfPtB. None of the post-and-core foundation restoration materials were able to match the performance of the ferrule group FPf (72667 cycles). In all groups, 100% of failures were catastrophic. The survival of extensively damaged endodontically treated incisors without a ferrule was slightly improved by the use of a fiber post with a bulk-fill composite resin core foundation restoration. However, none of the post-and-core techniques was able to compensate for the absence of a ferrule. The presence of the posts always adversely affected the failure mode. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

High-Fidelity Buckling Analysis of Composite Cylinders Using the STAGS Finite Element Code

NASA Technical Reports Server (NTRS)

Hilburger, Mark W.

2014-01-01

Results from previous shell buckling studies are presented that illustrate some of the unique and powerful capabilities in the STAGS finite element analysis code that have made it an indispensable tool in structures research at NASA over the past few decades. In particular, prototypical results from the development and validation of high-fidelity buckling simulations are presented for several unstiffened thin-walled compression-loaded graphite-epoxy cylindrical shells along with a discussion on the specific methods and user-defined subroutines in STAGS that are used to carry out the high-fidelity simulations. These simulations accurately account for the effects of geometric shell-wall imperfections, shell-wall thickness variations, local shell-wall ply-gaps associated with the fabrication process, shell-end geometric imperfections, nonuniform applied end loads, and elastic boundary conditions. The analysis procedure uses a combination of nonlinear quasi-static and transient dynamic solution algorithms to predict the prebuckling and unstable collapse response characteristics of the cylinders. Finally, the use of high-fidelity models in the development of analysis-based shell-buckling knockdown (design) factors is demonstrated.

Getting out and about in older adults: the nature of daily trips and their association with objectively assessed physical activity.

PubMed

Davis, Mark G; Fox, Kenneth R; Hillsdon, Melvyn; Coulson, Jo C; Sharp, Debbie J; Stathi, Afroditi; Thompson, Janice L

2011-10-21

A key public health objective is increasing health-enhancing physical activity (PA) for older adults (OAs). Daily trip frequency is independently associated with objectively assessed PA volumes (OAs). Little is known about correlates and these trips' transport mode, and how these elements relate to PA. to describe the frequency, purpose, and travel mode of daily trips in OAs, and their association with participant characteristics and objectively-assessed PA. Participants (n = 214, aged 78.1 SD 5.7 years), completed a seven-day trips log recording daily-trip frequency, purpose and transport mode. Concurrently participants wore an accelerometer which provided mean daily steps (steps·d-1), and minutes of moderate to vigorous PA (MVPA·d-1). Participants' physical function (PF) was estimated and demographic, height and weight data obtained. Trip frequency was associated with gender, age, physical function, walking-aid use, educational attainment, number of amenities within walking distance and cars in the household. Participants reported 9.6 (SD 4.2) trips per week (trips·wk-1). Most trips (61%) were by car (driver 44%, passenger 17%), 30% walking or cycling (active) and 9% public transport/other. Driving trips·wk-1 were more common in participants who were males (5.3 SD 3.6), well-educated (5.0 SD 4.3), high functioning (5.1 SD 4.6), younger (5.6 SD 4.9), affluent area residents (5.1 SD 4.2) and accessing > one car (7.2 SD 4.7). Active trips·wk-1 were more frequent in participants who were males (3.4 SD 3.6), normal weight (3.2 SD 3.4), not requiring walking aids (3.5 SD 3.3), well-educated (3.7 SD 0.7), from less deprived neighbourhoods (3.9 SD 3.9) and with ≥ 8 amenities nearby (4.4 SD 3.8).Public transport, and active trip frequency, were significantly associated with steps·d-1 (p < 0.001), even after adjustment for other trip modes and potential confounders. Public transport, active, or car driving trips were independently associated with minutes MVPA·d-1 (p < 0.01). Daily trips are associated with objectively-measured PA as indicated by daily MVPA and steps. Public transport and active trips are associated with greater PA than those by car, especially as a car passenger. Strategies encouraging increased trips, particularly active or public transport trips, in OAs can potentially increase their PA and benefit public health.

Electrosprayed core-shell solid dispersions of acyclovir fabricated using an epoxy-coated concentric spray head.

PubMed

Liu, Zhe-Peng; Cui, Lei; Yu, Deng-Guang; Zhao, Zhuan-Xia; Chen, Lan

2014-01-01

A novel structural solid dispersion (SD) taking the form of core-shell microparticles for poorly water-soluble drugs is reported for the first time. Using polyvinylpyrrolidone (PVP) as a hydrophilic polymer matrix, the SDs were fabricated using coaxial electrospraying (characterized by an epoxy-coated concentric spray head), although the core fluids were unprocessable using one-fluid electrospraying. Through manipulating the flow rates of the core drug-loaded solutions, two types of core-shell microparticles with tunable drug contents were prepared. They had average diameters of 1.36±0.67 and 1.74±0.58 μm, and were essentially a combination of nanocomposites with the active ingredient acyclovir (ACY) distributed in the inner core, and the sweeter sucralose and transmembrane enhancer sodium dodecyl sulfate localized in the outer shell. Differential scanning calorimetry and X-ray diffraction results demonstrated that ACY, sodium dodecyl sulfate, and sucralose were well distributed in the PVP matrix in an amorphous state because of favorable second-order interactions. In vitro dissolution and permeation studies showed that the core-shell microparticle SDs rapidly freed ACY within 1 minute and promoted nearly eightfold increases in permeation rate across the sublingual mucosa compared with raw ACY powders.

Greenhouse effect: temperature of a metal sphere surrounded by a glass shell and heated by sunlight

NASA Astrophysics Data System (ADS)

Nguyen, Phuc H.; Matzner, Richard A.

2012-01-01

We study the greenhouse effect on a model satellite consisting of a tungsten sphere surrounded by a thin spherical, concentric glass shell, with a small gap between the sphere and the shell. The system sits in vacuum and is heated by sunlight incident along the z-axis. This development is a generalization of the simple treatment of the greenhouse effect given by Kittel and Kroemer (1980 Thermal Physics (San Francisco: Freeman)) and can serve as a very simple model demonstrating the much more complex Earth greenhouse effect. Solution of the model problem provides an excellent pedagogical tool at the Junior/Senior undergraduate level.

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

Nag, Somnath; Singh, A. K.; Hagemann, G. B.

In this paper, high-spin states in 124Xe have been populated using the 80Se( 48Ca, 4n) reaction at a beam energy of 207 MeV and high-multiplicity, γ-ray coincidence events were measured using the Gammasphere spectrometer. Six high-spin rotational bands with moments of inertia similar to those observed in neighboring nuclei have been observed. The experimental results are compared with calculations within the framework of the Cranked Nilsson-Strutinsky model. Finally, it is suggested that the configurations of the bands involve excitations of protons across the Z = 50 shell gap coupled to neutrons within the N = 50 - 82 shell ormore » excited across the N = 82 shell closure.« less

Efficient and surface site-selective ion desorption by positron annihilation.

PubMed

Tachibana, Takayuki; Yamashita, Takashi; Nagira, Masaru; Yabuki, Hisakuni; Nagashima, Yasuyuki

2018-05-08

We compared positron- and electron-stimulated desorption (e + SD and ESD) of positive ions from a TiO 2 (110) surface. Although desorption of O + ions was observed in both experiments, the desorption efficiency caused by positron bombardment was larger by one order of magnitude than that caused by electron bombardment at an incident energy of 500 eV. e + SD of O + ions remained highly efficient with incident positron energies between 10 eV and 600 eV. The results indicate that e + SD of O + ions is predominantly caused by pair annihilation of surface-trapped positrons with inner-shell electrons. We also tested e + SD from water chemisorbed on the TiO 2 surface and found that the desorption of specific ions was enhanced by positron annihilation, above the ion yield with electron bombardment. This finding corroborates our conclusion that annihilation-site selectivity of positrons results in site-selective ion desorption from a bombarded surface.

Temporal Changes in Forest Contexts at Multiple Extents: Three Decades of Fragmentation in the Gran Chaco (1979-2010), Central Argentina.

PubMed

Frate, Ludovico; Acosta, Alicia T R; Cabido, Marcelo; Hoyos, Laura; Carranza, Maria Laura

2015-01-01

The context in which a forest exists strongly influences its function and sustainability. Unveiling the multi-scale nature of forest fragmentation context is crucial to understand how human activities affect the spatial patterns of forests across a range of scales. However, this issue remains almost unexplored in subtropical ecosystems. In this study, we analyzed temporal changes (1979-2010) in forest contexts in the Argentinean dry Chaco at multiple extents. We classified forests over the last three decades based on forest context amount (Pf) and structural connectivity (Pff), which were measured using a moving window approach fixed at eight different extents (from local, ~ 6 ha, to regional, ~ 8300 ha). Specific multi-scale forest context profiles (for the years 1979 and 2010) were defined by projecting Pf vs. Pff mean values and were compared across spatial extents. The distributions of Pf across scales were described by scalograms and their shapes over time were compared. The amount of agricultural land and rangelands across the scales were also analyzed. The dry Chaco has undergone an intensive process of fragmentation, resulting in a shift from landscapes dominated by forests with gaps of rangelands to landscapes where small forest patches are embedded in agricultural lands. Multi-scale fragmentation analysis depicted landscapes in which local exploitation, which perforates forest cover, occurs alongside extensive forest clearings, reducing forests to small and isolated patches surrounded by agricultural lands. In addition, the temporal diminution of Pf's variability along with the increment of the mean slope of the Pf 's scalograms, indicate a simplification of the spatial pattern of forest over time. The observed changes have most likely been the result of the interplay between human activities and environmental constraints, which have shaped the spatial patterns of forests across scales. Based on our results, strategies for the conservation and sustainable management of the dry Chaco should take into account both the context of each habitat location and the scales over which a forest pattern might be preserved, altered or restored.

Menstruum induces changes in mesothelial cell morphology.

PubMed

Koks, C A; Demir Weusten, A Y; Groothuis, P G; Dunselman, G A; de Goeij, A F; Evers, J L

2000-01-01

In previous studies, we have shown that menstrual endometrium preferentially adheres to the subepithelial lining of the peritoneum. It remains to be elucidated, however, whether this damage is preexisting or inflicted by the menstrual tissue itself. We hypothesized that the menstrual tissue itself damages the peritoneum. To investigate this, the viability of menstrual endometrial tissue in peritoneal fluid (PF) was evaluated and the morphologic changes in the mesothelial cells were studied by in vitro cocultures of menstruum with mesothelial cell monolayers. Menstruum was collected with a menstrual cup. Endometrial tissue was isolated from the menstruum, resuspended in culture medium or in the cell-free fraction of PF and cultured for 24, 48 or 72 h. A 3(4, 5-dimethylthiazolyl-2)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to obtain a relative measure of viable adhered endometrial cells. Mesothelial cells isolated from human omental tissue were cultured on Matrigel or uncoated plastic. At confluence, overnight cocultures were performed and scanning electron microscopy was used to evaluate the morphologic changes. The viability of endometrial fragments was 84% (n = 36, p < 0.05), 82% (n = 27, not significant) and 104% (n = 14, not significant) when cultured in the cell-free fraction of PF for 24, 48 and 72 h, respectively, when compared to medium with 10% fetal calf serum. Menstrual endometrial fragments or menstrual serum added to and cocultured with mesothelial cells induced severe morphologic alterations of the latter, including retraction, shrinking and gap formation. Similar morphologic changes were observed when mesothelial cells were cocultured with menstrual endometrial fragments in PF or in culture inserts. Incubation with conditioned medium from cultured menstrual endometrium induced similar but less pronounced changes in morphology. In conclusion, menstrual endometrial fragments remain viable in PF in vitro for at least 72 h. Antegradely shed menstruum induces changes in mesothelial cell morphology, including retraction and shrinking with exposure of the underlying surface. These findings suggest that menstruum is harmful to the peritoneal lining. Therefore, by local destruction of the mesothelial layer, menstrual endometrium is able to create sites for adhesion. Copyright 2000 S. Karger AG, Basel

A secretory multifunctional serine protease, DegP of Plasmodium falciparum, plays an important role in thermo-oxidative stress, parasite growth and development.

PubMed

Sharma, Shweta; Jadli, Mohit; Singh, Anu; Arora, Kavita; Malhotra, Pawan

2014-03-01

Plasmodium falciparum heat shock proteins and proteases are known for their indispensable roles in parasite virulence and survival in the host cell. They neutralize various host-derived stress responses that are deleterious for parasite growth and invasion. We report identification and functional characterization of the first DegP from an apicomplexan (P. falciparum). To determine the molecular identity and functions of the parasite-encoded DegP, we complemented the Escherichia coli degP null mutant with a putative PfdegP gene, and the results showed that PfDegP complements the growth defect of the temperature sensitive DegP-deficient mutant and imparts resistance to non-permissive temperatures and oxidative stress. Molecular interaction studies showed that PfDegP exists as a complex with parasite-encoded heat shock protein 70, iron superoxide dismutase and enolase. DegP expression is significantly induced in parasite culture upon heat shock/oxidative stress. Our data suggest that the PfDegP protein may play a role in the growth and development of P. falciparum through its ability to confer protection against thermal/oxidative stress. Antibody against DegP showed anti-plasmodial activity against blood-stage parasites in vitro, suggesting that PfDegP and its associated complex may be a potential focus for new anti-malarial therapies. ●PfDegP physically interacts with PfHsp70 and PfEno by anti-bait co-immunoprecipitation (View interaction) ●PfDegP physically interacts with PfEno, PfSod, PfOat, PfHsp70, PfLDH and PfGpi by anti-bait co-immunoprecipitation (View interaction) ●PfHsp-70 and PfDegP co-localize by fluorescence microscopy (View interaction) ●PfDegP physically interacts with PfOat, PfHsp70, PfEno, PfSod, PfGpi and PfLDH by surface plasmon resonance (View interaction) ●PfEno and PfDegP co-localize by fluorescence microscopy (View interaction) ●PfDegP and PfHsp70 co-localize by co-sedimentation through density gradient (View interaction). © 2014 FEBS.

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

Dang, Liem X.; Chang, Tsun-Mei

In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li +(aq) and the kinetics of ion pairings in lithium-ion batteries (LIB). We report one of the first computer simulations of the exchange dynamics around hydrated Li + in acetonitrile (ACN), which is common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li +-[BF 4] and Li +-[PF 6] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells aroundmore » Li +(aq). We calculate exchange rates using transition state theory and weighted them with transmission coefficients determined by the reactive flux and Impey, Madden, and McDonald approaches and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li +-[BF 4] and Li +-[PF 6] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.« less

Experimental evidence for 56Ni-core breaking from the low-spin structure of the N=Z nucleus 5829Cu29

NASA Astrophysics Data System (ADS)

Lisetskiy, A. F.; Pietralla, N.; Honma, M.; Schmidt, A.; Schneider, I.; Gade, A.; von Brentano, P.; Otsuka, T.; Mizusaki, T.; Brown, B. A.

2003-09-01

Low-spin states in the odd-odd N=Z nucleus 58Cu were investigated with the 58Ni(p,nγ)58Cu fusion evaporation reaction at the FN-TANDEM accelerator in Cologne. γγ-coincidences, γγ-angular correlations, and signs of γ-ray polarizations were measured. Seventeen low-spin states below 3.6 MeV and 17 new transitions were observed. Ten multipole mixing ratios and 17 γ-branching ratios were determined for the first time. New detailed spectroscopic information on the 2+2 state, the isobaric analogue state (IAS) of the 2+1,T=1 state of 58Ni, makes 58Cu the heaviest odd-odd N=Z nucleus with known B(E2;2+,T=1→0+,T=1) value. The 4+ state at 2.751 MeV, observed here for the first time, is identified as the IAS of the 4+1,T=1 state in 58Ni. The new data are compared to full pf-shell-model calculations with the GXPF1 residual interaction and to calculations within a pf5/2 configurational space with a residual surface δ interaction. The role of the 56Ni core excitations for the low-spin structure in 58Cu is discussed.

Single domain antibody-quantum dot conjugates for ricin detection by both fluoroimmunoassay and surface plasmon resonance.

PubMed

Anderson, George P; Glaven, Richard H; Algar, W Russ; Susumu, Kimihiro; Stewart, Michael H; Medintz, Igor L; Goldman, Ellen R

2013-07-05

The combination of stable biorecognition elements and robust quantum dots (QDs) has the potential to yield highly effective reporters for bioanalyses. Llama-derived single domain antibodies (sdAb) provide small thermostable recognition elements that can be easily manipulated using standard DNA methods. The sdAb was self-assembled on dihydrolipoic acid (DHLA) ligand-capped CdSe-ZnS core-shell QDs made in our laboratory through the polyhistidine tail of the protein, which coordinated to zinc ions on the QD surface. The sdAb-QD bioconjugates were then applied in both fluorometric and surface plasmon resonance (SPR) immunoassays for the detection of ricin, a potential biothreat agent. The sdAb-QD conjugates functioned in fluoroimmunoassays for the detection of ricin, providing equivalent limits of detection when compared to the same anti-ricin sdAb labeled with a conventional fluorophore. In addition, the DHLA-QD-sdAb conjugates were very effective reporter elements in SPR sandwich assays, providing more sensitive detection with a signal enhancement of ~10-fold over sdAb reporters and 2-4 fold over full sized antibody reporters. Commercially prepared streptavidin-modified polymer-coated QDs also amplified the SPR signal for the detection of ricin when applied to locations where biotinylated anti-ricin sdAb was bound to target; however, we observed a 4-fold greater amplification when using the DHLA-QD-sdAb conjugates in this format. Copyright © 2013. Published by Elsevier B.V.

What's in a Name?FRAMING:Martin-Bradshaw DYSfunctionality = Siegel ``Buzzwordism,Bandwagonism&Sloganeering For: Fun, Profit,Survival,Ego": From SOC to FLT Proof to High-Tc to Spintronics to Giant-Magnetoresistance: Ethics??? SHMETHICS!!! Rampant Sociolog

NASA Astrophysics Data System (ADS)

Siegel, Edward

2008-03-01

Buzzwordism,Bandwagonism,Sloganeering for:Fun,Profit,Survival, Ego=ethics DYSunctionality: Digits log-law: Siegel INVERSION: bosons=digits; Excluded d=0? P(0)=oo V P(1)

Electronic and Optical Properties of Core/Shell Pb16X16/Cd52X52 (X =S, Se, Te) Quantum Dots

NASA Astrophysics Data System (ADS)

Tamukong, Patrick; Mayo, Michael; Kilina, Svetlana

2015-03-01

The electronic and optoelectronic properties of semiconductor quantum dots (QDs) are mediated by surface defects due to the presence of dangling bonds producing trap states within the HOMO-LUMO energy gap, and contributing to fluorescence quenching. Surface capping ligands are generally used to alleviate this problem and increase the quantum yields of QDs. An alternative way is to synthesize core-shell QD structures; i.e., a QD core with a shell of another semiconductor material. We have investigated the effects of Cd52X52 shells on the photoexcited dynamics of Pb16X16 (X =S, Se, Te) QDs. The thin (~ 0.50 nm) shells were found to result largely in type I core/shell structures and a blue shift of the absorption spectra. Our studies revealed fairly strong core-shell hybridization in the electronic states close to the conduction band (CB) edge for Pb16S16andPb16Se16 cores, whereas for the Pb16Te16 core, such CB states were largely shell-like in nature. Nonadiabatic DFT-based dynamics, coupled with the surface hopping method, was used to study the effects of the core and shell compositions on energy relaxation rates in these systems.

A Unified Equation of State on a Microscopic Basis : Implications for Neutron Stars Structure and Cooling

NASA Astrophysics Data System (ADS)

Burgio, G. F.

2018-03-01

We discuss the structure of Neutron Stars by modelling the homogeneous nuclear matter of the core by a suitable microscopic Equation of State, based on the Brueckner-Hartree-Fock many-body theory, and the crust, including the pasta phase, by the BCPM energy density functional which is based on the same Equation of State. This allows for a uni ed description of the Neutron Star matter over a wide density range. A comparison with other uni ed approaches is discussed. With the same Equation of State, which features strong direct Urca processes and using consistent nuclear pairing gaps as well as effective masses, we model neutron star cooling, in particular the current rapid cooldown of the neutron star Cas A. We nd that several scenarios are possible to explain the features of Cas A, but only large and extended proton 1 S 0 gaps and small neutron 3 PF 2 gaps can accommodate also the major part of the complete current cooling data.

Additional compound semiconductor nanowires for photonics

NASA Astrophysics Data System (ADS)

Ishikawa, F.

2016-02-01

GaAs related compound semiconductor heterostructures are one of the most developed materials for photonics. Those have realized various photonic devices with high efficiency, e. g., lasers, electro-optical modulators, and solar cells. To extend the functions of the materials system, diluted nitride and bismide has been paid attention over the past decade. They can largely decrease the band gap of the alloys, providing the greater tunability of band gap and strain status, eventually suppressing the non-radiative Auger recombinations. On the other hand, selective oxidation for AlGaAs is a vital technique for vertical surface emitting lasers. That enables precisely controlled oxides in the system, enabling the optical and electrical confinement, heat transfer, and mechanical robustness. We introduce the above functions into GaAs nanowires. GaAs/GaAsN core-shell nanowires showed clear redshift of the emitting wavelength toward infrared regime. Further, the introduction of N elongated the carrier lifetime at room temperature indicating the passivation of non-radiative surface recombinations. GaAs/GaAsBi nanowire shows the redshift with metamorphic surface morphology. Selective and whole oxidations of GaAs/AlGaAs core-shell nanowires produce semiconductor/oxide composite GaAs/AlGaOx and oxide GaOx/AlGaOx core-shell nanowires, respectively. Possibly sourced from nano-particle species, the oxide shell shows white luminescence. Those property should extend the functions of the nanowires for their application to photonics.

Fe-N co-doped SiO2@TiO2 yolk-shell hollow nanospheres with enhanced visible light photocatalytic degradation

NASA Astrophysics Data System (ADS)

Wan, Hengcheng; Yao, Weitang; Zhu, Wenkun; Tang, Yi; Ge, Huilin; Shi, Xiaozhong; Duan, Tao

2018-06-01

SiO2@TiO2 yolk@shell hollow nanospheres (STNSs) is considered as an outstanding photocatalyst due to its tunable structure and composition. Based on this point, we present an unprecedentedly excellent photocatalytic property of STNSs toward tannic acid via a Fe-N co-doped strategy. Their morphologies, compositions, structure and properties are characterized. The Fe-N co-doped STNSs formed good hollow yolk@shell structure. The results show that the energy gap of the composites can be downgraded to 2.82 eV (pure TiO2 = 3.2 eV). Photocatalytic degradation of tannic acid (TA, 30 mg L-1) under visible light (380 nm < λ < 780 nm) irradiation is used to evaluate the photocatalytic activity of the composites. Compared with pure TiO2 nanospheres, non-doped STNSs and N-doped STNSs, the Fe-N co-doped STNSs exhibits the highest activity, which can degrade 99.5% TA into CO2 and H2O in 80 min. The probable degradation mechanism of the composites is simultaneously proposed, the band gap of STNSs becomes narrow by co-doping Fe-N, so that the TiO2 shell can stimulate electrons under visible light exposure, generate the ions of radOH and radO2- with a strong oxidizing property. Therefore this approach works is much desired for radioactive organic wastewater photocatalytic degradation.

A systematic study of superheavy nuclei for Z = 114 and beyond using the relativistic mean field approach

NASA Astrophysics Data System (ADS)

Patra, S. K.; Wu, Cheng-Li; Praharaj, C. R.; Gupta, Raj K.

1999-05-01

We have studied the structural properties of even-even, neutron deficient, Z = 114-126, superheavy nuclei in the mass region A ˜ 270-320, using an axially deformed relativistic mean field model. The calculations are performed with three parameter sets (NL1, TM1 and NL-SH), in order to see the dependence of the structural properties on the force used. The calculated ground state shapes are found to be parameter dependent. For some parameter sets, many of the nuclei are degenerate in their ground state configuration. Special attention is given to the investigation of the magic structures (spherical shell closures) in the superheavy region. We find that some known magic numbers are absent and new closed shells are predicted. Large shell gaps appear at Z = 80, 92, (114), 120 and 138, N = 138, (164), (172), 184, (198), (228) and 258, irrespective of the parameter sets used. The numbers in parenthesis are those which correspond to relatively smaller gaps. The existence of new magic numbers in the valley of superheavy elements is discussed. It is suggested that nuclei around Z = 114 and N = 164 ˜ 172 could be considered as candidates for the next search of superheavy nuclei. The existence of superheavy islands around Z = 120 and N = 172 or N = 184 double shell closure is also discussed.

Surface passivation and self-regulated shell growth in selective area-grown GaN-(Al,Ga)N core-shell nanowires.

PubMed

Hetzl, Martin; Winnerl, Julia; Francaviglia, Luca; Kraut, Max; Döblinger, Markus; Matich, Sonja; Fontcuberta I Morral, Anna; Stutzmann, Martin

2017-06-01

The large surface-to-volume ratio of GaN nanowires implicates sensitivity of the optical and electrical properties of the nanowires to their surroundings. The implementation of an (Al,Ga)N shell with a larger band gap around the GaN nanowire core is a promising geometry to seal the GaN surface. We investigate the luminescence and structural properties of selective area-grown GaN-(Al,Ga)N core-shell nanowires grown on Si and diamond substrates. While the (Al,Ga)N shell allows a suppression of yellow defect luminescence from the GaN core, an overall intensity loss due to Si-related defects at the GaN/(Al,Ga)N interface has been observed in the case of Si substrates. Scanning transmission electron microscopy measurements indicate a superior crystal quality of the (Al,Ga)N shell along the nanowire side facets compared to the (Al,Ga)N cap at the top facet. A nucleation study of the (Al,Ga)N shell reveals a pronounced bowing of the nanowires along the c-direction after a short deposition time which disappears for longer growth times. This is assigned to an initially inhomogeneous shell nucleation. A detailed study of the proceeding shell growth allows the formulation of a strain-driven self-regulating (Al,Ga)N shell nucleation model.

Spectrum of Aortic Valve Abnormalities Associated with Aortic Dilation Across Age Groups in Turner Syndrome

PubMed Central

Olivieri, Laura J.; Baba, Ridhwan Y.; Arai, Andrew E.; Bandettini, W. Patricia; Rosing, Douglas R.; Bakalov, Vladimir; Sachdev, Vandana; Bondy, Carolyn A.

2014-01-01

Background Congenital aortic valve fusion is associated with aortic dilation, aneurysm and rupture in girls and women with Turner syndrome (TS). Our objective was to characterize aortic valve structure in subjects with TS, and determine the prevalence of aortic dilation and valve dysfunction associated with different types of aortic valves. Methods and Results The aortic valve and thoracic aorta were characterized by cardiovascular magnetic resonance imaging in 208 subjects with TS in an IRB-approved natural history study. Echocardiography was used to measure peak velocities across the aortic valve, and the degree of aortic regurgitation. Four distinct valve morphologies were identified: tricuspid aortic valve (TAV) 64%(n=133), partially fused aortic valve (PF) 12%(n=25), bicuspid aortic valve (BAV) 23%(n=47), and unicuspid aortic valve (UAV) 1%(n=3). Age and body surface area (BSA) were similar in the 4 valve morphology groups. There was a significant trend, independent of age, towards larger BSA-indexed ascending aortic diameters (AADi) with increasing valve fusion. AADi were (mean +/− SD) 16.9 +/− 3.3 mm/m2, 18.3 +/− 3.3 mm/m2, and 19.8 +/− 3.9 mm/m2 (p<0.0001) for TAV, PF and BAV+UAV respectively. PF, BAV, and UAV were significantly associated with mild aortic regurgitation and elevated peak velocities across the aortic valve. Conclusions Aortic valve abnormalities in TS occur with a spectrum of severity, and are associated with aortic root dilation across age groups. Partial fusion of the aortic valve, traditionally regarded as an acquired valve problem, had an equal age distribution and was associated with an increased AADi. PMID:24084490

An Investigation Into the Relationship Between Maximum Isometric Strength and Vertical Jump Performance.

PubMed

Thomas, Christopher; Jones, Paul A; Rothwell, James; Chiang, Chieh Y; Comfort, Paul

2015-08-01

Research has demonstrated a clear relationship between dynamic strength and vertical jump (VJ) performance; however, the relationship of isometric strength and VJ performance has been studied less extensively. The aim of this study was to determine the relationship between isometric strength and performance during the squat jump (SJ) and countermovement jump (CMJ). Twenty-two male collegiate athletes (mean ± SD; age = 21.3 ± 2.9 years; height = 175.63 ± 8.23 cm; body mass = 78.06 ± 10.77 kg) performed isometric midthigh pulls (IMTPs) to assess isometric peak force (IPF), maximum rate of force development, and impulse (IMP) (I100, I200, and I300). Force-time data, collected during the VJs, were used to calculate peak velocity, peak force (PF), peak power (PP), and jump height. Absolute IMTP measures of IMP showed the strongest correlations with VJ PF (r = 0.43-0.64; p ≤ 0.05) and VJ PP (r = 0.38-0.60; p ≤ 0.05). No statistical difference was observed in CMJ height (0.33 ± 0.05 m vs. 0.36 ± 0.05 m; p = 0.19; ES = -0.29) and SJ height performance (0.29 ± 0.06 m vs. 0.33 ± 0.05 m; p = 0.14; ES = -0.34) when comparing stronger to weaker athletes. The results of this study illustrate that absolute IPF and IMP are related to VJ PF and PP but not VJ height. Because stronger athletes did not jump higher than weaker athletes, dynamic strength tests may be more practical methods of assessing the relationships between relative strength levels and dynamic performance in collegiate athletes.

Sonoclot evaluation of whole blood coagulation in healthy adult dogs.

PubMed

Babski, Danielle M; Brainard, Benjamin M; Krimer, Paula M; Ralph, Alan G; Pittman, Jennifer R; Koenig, Amie

2012-12-01

To establish a standard protocol for analysis of canine whole blood and generate reference intervals for healthy dogs using the Sonoclot analyzer, and to compare Sonoclot values to standard and viscoelastic coagulation tests. Prospective study. Veterinary University research facility and teaching hospital. Twelve healthy random source dogs and 52 healthy dogs from the general veterinary school population. Blood sampling for viscoelastic coagulation testing. Blood was collected from 12 healthy adult dogs by jugular venipuncture. After a rest period at room temperature of 30, 60, or 120 minutes, 340 μL of citrated blood was added to 20 μL of 0.2 M CaCl(2) in 1 of 2 cuvette types warmed to 37° C. Cuvettes contained a magnetic stir-bar with glass beads (gbACT+) or only a magnetic stir-bar (nonACT). Reference interval samples were collected from 52 healthy adult dogs and analyzed in duplicate. The ACT, CR, and PF were not affected by duration of rest period for either cuvette type. ACT variability was decreased when using gbACT+ cuvettes (P < 0.05). In normal dogs reference intervals (mean ± 2 SD) using gbACT+ cuvettes were: ACT 56.0-154.0 seconds, CR 14.85-46.0, and PF 2.1-4.05. ACT correlated to TEG R-time, K-time, and angle, while CR correlated with all TEG parameters. Fibrinogen correlated with ACT, CR, and PF. Sonoclot did not correlate with other common coagulation tests. Sonoclot provides viscoelastic evaluation of canine whole blood coagulation and correlated to several TEG parameters and fibrinogen. A standard protocol and reference intervals were established. © Veterinary Emergency and Critical Care Society 2012.

Comparing the lower limb tasks questionnaire to the Western Ontario and McMaster Universities Osteoarthritis Index: agreement, responsiveness, and convergence with physical performance for knee osteoarthritis patients.

PubMed

McKay, Carly; Prapavessis, Harry; McNair, Peter

2013-03-01

To compare the Lower Limb Tasks Questionnaire (LLTQ) with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in terms of agreement, responsiveness, and convergence. Cross-sectional with an exploratory repeated-measures subsample analysis. Community-based seniors' centers and arthritis clinics. Individuals with symptomatic knee osteoarthritis (N=76) participated, with a subsample of 18 participants contributing to the pre- and postarthroplasty subanalysis. Not applicable. Bland and Altman plots of agreement with 95% limits of agreement, statistical responsiveness, and standardized response mean (SRM) were calculated for LLTQ and WOMAC subscales. Both t tests and Wilcoxon rank-sum tests were used to examine changes in pre- and postarthroplasty self-reported function, 50-ft walk speed, stair ascent/descent speed, and isometric quadriceps strength. The agreement (bias) of the LLTQ activities of daily living (ADL) subscale when compared with the WOMAC physical function (PF) subscale was 1%±10% (mean ± SD), and the 95% limits of agreement were -19% to +22%. The statistical responsiveness of the WOMAC-PF and LLTQ ADL was 1.17 and -.63, respectively. The SRMs for these scales were .90 and -.61, respectively. The WOMAC-PF scores showed a notable improvement over the first 6 weeks postarthroplasty, while LLTQ ADL scores were unchanged. The objective measures of function were all significantly worse at 6 weeks. The LLTQ demonstrated adequate agreement with the WOMAC and acceptable responsiveness for use in place of the WOMAC in nonspecialized clinics. The LLTQ may more accurately represent functional status after total knee arthroplasty, but further study in larger samples is recommended. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Protein-protein interaction studies reveal the Plasmodium falciparum merozoite surface protein-1 region involved in a complex formation that binds to human erythrocytes.

PubMed

Paul, Gourab; Deshmukh, Arunaditya; Kumar Chourasia, Bishwanath; Kalamuddin, Md; Panda, Ashutosh; Kumar Singh, Susheel; Gupta, Puneet K; Mohmmed, Asif; Chauhan, Virender S; Theisen, Michael; Malhotra, Pawan

2018-03-29

Plasmodium falciparum merozoite surface protein (PfMSP) 1 has been studied extensively as a vaccine candidate antigen. PfMSP-1 undergoes proteolytic processing into four major products, such as p83, p30, p38, and p42, that are associated in the form of non-covalent complex(s) with other MSPs. To delineate MSP1 regions involved in the interaction with other MSPs, here we expressed recombinant proteins (PfMSP-1 65 ) encompassing part of p38 and p42 regions and PfMSP-1 19 PfMSP-1 65 interacted strongly with PfMSP-3, PfMSP-6, PfMSP-7, and PfMSP-9, whereas PfMSP-1 19 did not interact with any of these proteins. Since MSP-1 complex binds human erythrocytes, we examined the ability of these proteins to bind human erythrocyte. Among the proteins of MSP-1 complex, PfMSP-6 and PfMSP-9 bound to human erythrocytes. Serological studies showed that PfMSP-1 65 was frequently recognized by sera from malaria endemic regions, whereas this was not the case for PfMSP-1 19 In contrast, antibodies against PfMSP-1 19 showed much higher inhibition of merozoite invasion compared with antibodies against the larger PfMSP-1 65 fragment. Importantly, anti-PfMSP-1 19 antibodies recognized both recombinant proteins, PfMSP-1 19 and PfMSP-1 65 ; however, anti-PfMSP-1 65 antibody failed to recognize the PfMSP-1 19 protein. Taken together, these results demonstrate that PfMSP-1 sequences upstream of the 19 kDa C-terminal region are involved in molecular interactions with other MSPs, and these sequences may probably serve as a smoke screen to evade antibody response to the membrane-bound C-terminal 19 kDa region. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Correlation between the band gap expansion and melting temperature depression of nanostructured semiconductors

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

Li, Jianwei, E-mail: jwl189@163.com; Zhao, Xinsheng; Liu, Xinjuan

The band gap and melting temperature of a semiconductor are tunable with the size and shape of the specimen at the nanometer scale, and related mechanisms remain as yet unclear. In order to understand the common origin of the size and shape effect on these two seemingly irrelevant properties, we clarify, correlate, formulate, and quantify these two properties of GaAs, GaN, InP, and InN nanocrystals from the perspectives of bond order-length-strength correlation using the core-shell configuration. The consistency in the theoretical predictions, experimental observations, and numerical calculations verify that the broken-bond-induced local bond contraction and strength gain dictates the bandmore » gap expansion, while the atomic cohesive energy loss due to bond number reduction depresses the melting point. The fraction of the under-coordinated atoms in the skin shell quantitatively determines the shape and size dependency. The atomic under-coordination in the skin down to a depth of two atomic layers inducing a change in the local chemical bond is the common physical origin.« less

Unitary Fermi gas in a harmonic trap

NASA Astrophysics Data System (ADS)

Chang, S. Y.; Bertsch, G. F.

2007-08-01

We present an ab initio calculation of small numbers of trapped, strongly interacting fermions using the Green’s function Monte Carlo method. The ground-state energy, density profile, and pairing gap are calculated for particle numbers N=2 22 using the parameter-free “unitary” interaction. Trial wave functions are taken in the form of correlated pairs in a harmonic oscillator basis. We find that the lowest energies are obtained with a minimum explicit pair correlation beyond that needed to exploit the degeneracy of oscillator states. We find that the energies can be well fitted by the expression aTFETF+Δmod(N,2) where ETF is the Thomas-Fermi energy of a noninteracting gas in the trap and Δ is the pairing gap. There is no evidence of a shell correction energy in the systematics, but the density distributions show pronounced shell effects. We find the value Δ=0.7±0.2ω for the pairing gap. This is smaller than the value found for the uniform gas at a density corresponding to the central density of the trapped gas.

Low-Z shore of the "island of inversion" and the reduced neutron magicity toward 28O

NASA Astrophysics Data System (ADS)

Doornenbal, P.; Scheit, H.; Takeuchi, S.; Utsuno, Y.; Aoi, N.; Li, K.; Matsushita, M.; Steppenbeck, D.; Wang, H.; Baba, H.; Ideguchi, E.; Kobayashi, N.; Kondo, Y.; Lee, J.; Michimasa, S.; Motobayashi, T.; Otsuka, T.; Sakurai, H.; Takechi, M.; Togano, Y.; Yoneda, K.

2017-04-01

The two odd-even fluorine isotopes F,2927 were studied via in-beam γ -ray spectroscopy at the RIKEN Radioactive Isotope Beam Factory. A secondary beam of 30Ne was used to induce one-proton and one-proton-two-neutron removal reactions on carbon and polyethylene targets at midtarget energies of 228 MeV/u . Excited states were observed at 915(12) keV for 27F and at 1080(18) keV for 29F. Both were assigned a 1 /21+ spin and parity. The low transition energy for 29F largely disagrees with shell model predictions restricted to the s d model space. Calculations using effective interactions that include the neutron p f shell indicate that the N =20 gap is quenched for 29F, thus extending the "island of inversion" to isotopes with proton number Z =9 . Variations of the N =20 gap further reveal a strong correlation to the 1 /21+ level energy in 29F and suggest a persistent reduced neutron gap for 28O.

Liquid-liquid phase separation and core-shell structure of ternary Al-In-Sn immiscible alloys

NASA Astrophysics Data System (ADS)

Zhao, Degang; Bo, Lin; Wang, Lin; Li, Shanshan

2018-04-01

In this study, the liquid-liquid phase separation of four kinds of ternary immiscible Al-In-Sn melts was investigated with resistivity and thermodynamics method. The nonlinear changes in ρ-T and DSC curves of Al-In-Sn immiscible alloys above monotectic reaction temperature revealed the occurrence of liquid-liquid phase separation of Al-In-Sn melts. The monotectic temperature, liquid phase separation temperature and immiscible gap of ternary Al-In-Sn alloys were lower than those of binary Al-In alloy. With the Al content decreasing, the immiscible gap of Al-In-Sn alloy decreased. The composition of Al80In10Sn10, Al70In15Sn15, Al60In20Sn20 and Al50In25Sn25 was located in the immiscible zone of Al-In-Sn system. Due to the differences of Stokes effect, Marangoni convection and immiscible gap, the solidification morphology of four kinds of Al-In-Sn monotectic alloy was different. The core–shell structure of Al-In-Sn monotectic alloy can form within a certain range of composition.

Controllable synthesis of ZnxCd1-xS@ZnO core-shell nanorods with enhanced photocatalytic activity.

PubMed

Xie, Shilei; Lu, Xihong; Zhai, Teng; Gan, Jiayong; Li, Wei; Xu, Ming; Yu, Minghao; Zhang, Yuan-Ming; Tong, Yexiang

2012-07-17

We report the synthesis of Zn(x)Cd(1-x)S@ZnO nanorod arrays via a facile two-step process and the implementation of these core-shell nanorods as an environmental friendly and recyclable photocatalyst for methyl orange degradation. The band gap of Zn(x)Cd(1-x)S@ZnO core-shell nanorods can be readily tunable by adjusting the ratio of Zn/Cd during the synthesis. These Zn(x)Cd(1-x)S@ZnO core-shell nanorods exhibit a high photocatalytic activity and good stability in the degradation of the methyl orange. Moreover, these films grown on FTO substrates make the collection and recycle of the photocatalyst easier. These findings may open new opportunities for the design of effective, stable, and easy-recyclable photocatalytic materials.

Demonstration of a Three-dimensional Negative Index Medium Operated at Multiple-angle Incidences by Monolithic Metallic Hemispherical Shells

NASA Astrophysics Data System (ADS)

Yeh, Ting-Tso; Huang, Tsung-Yu; Tanaka, Takuo; Yen, Ta-Jen

2017-04-01

We design and construct a three-dimensional (3D) negative index medium (NIM) composed of gold hemispherical shells to supplant an integration of a split-ring resonator and a discrete plasmonic wire for both negative permeability and permittivity at THz gap. With the proposed highly symmetric gold hemispherical shells, the negative index is preserved at multiple incident angles ranging from 0° to 85° for both TE and TM waves, which is further evidenced by negative phase flows in animated field distributions and outweighs conventional fishnet structures with operating frequency shifts when varying incident angles. Finally, the fabrication of the gold hemispherical shells is facilitated via standard UV lithographic and isotropic wet etching processes and characterized by μ-FTIR. The measurement results agree the simulated ones very well.

Serum 8,12-iso-iPF2α-VI isoprostane marker of oxidative damage and cognition deficits in children with konzo.

PubMed

Makila-Mabe, Bumoko G; Kikandau, Kambale J; Sombo, Thérèse M; Okitundu, Daniel L; Mwanza, Jean-Claude; Boivin, Michael J; Ngoyi, Mumba D; Muyembe, Jean-Jacques T; Banea, Jean-Pierre; Boss, Gerard R; Tshala-Katumbay, Desiré

2014-01-01

We sought to determine whether motor and cognitive deficits associated with cassava (food) cyanogenic poisoning were associated with high concentrations of F2-isoprostanes, well-established indicators of oxidative damage. Concentrations of serum F2-isoprostanes were quantified by LC-MS/MS and anchored to measures of motor proficiency and cognitive performance, which were respectively assessed through BOT-2 (Bruininks/Oseretsky Test, 2nd Edition) and KABC-II (Kaufman Assessment Battery for Children, 2nd edition) testing of 40 Congolese children (21 with konzo and 19 presumably healthy controls, overall mean age (SD): 9.3 (3.2) years). Exposure to cyanide was ascertained by concentrations of its main metabolite thiocyanate (SCN) in plasma and urine. Overall, SCN concentrations ranged from 91 to 325 and 172 to 1032 µmol/l in plasma and urine, respectively. Serum isoprostanes ranged from 0.1 to 0.8 (Isoprostane-III), 0.8 to 8.3 (total Isoprostane-III), 0.1 to 1.5 (Isoprostane-VI), 2.0 to 9.0 (total Isoprostane-VI), or 0.2 to 1.3 ng/ml (8,12-iso-iPF2α-VI isoprostane). Children with konzo poorly performed at the BOT-2 and KABC-II testing relative to presumably healthy children (p<0.01). Within regression models adjusting for age, gender, motor proficiency, and other biochemical variables, 8,12-iso-iPF2α-VI isoprostane was significantly associated with the overall cognitive performance (β = -32.36 (95% CI: -51.59 to -13.03; P<0.001). This model explained over 85% of variation of the KABC-II score in children with konzo, but was not significant in explaining the motor proficiency impairment. These findings suggest that cognitive deficits and, possibly, brain injury associated with cassava poisoning is mediated in part by oxidative damage in children with konzo. 8,12-iso-iPF2α-VI isoprostane appears to be a good marker of the neuropathogenic mechanisms of konzo and may be used to monitor the impact of interventional trials to prevent the neurotoxic effects of cassava cyanogenic poisoning.

In-medium similarity renormalization group for closed and open-shell nuclei

NASA Astrophysics Data System (ADS)

Hergert, H.

2017-02-01

We present a pedagogical introduction to the in-medium similarity renormalization group (IMSRG) framework for ab initio calculations of nuclei. The IMSRG performs continuous unitary transformations of the nuclear many-body Hamiltonian in second-quantized form, which can be implemented with polynomial computational effort. Through suitably chosen generators, it is possible to extract eigenvalues of the Hamiltonian in a given nucleus, or drive the Hamiltonian matrix in configuration space to specific structures, e.g., band- or block-diagonal form. Exploiting this flexibility, we describe two complementary approaches for the description of closed- and open-shell nuclei: the first is the multireference IMSRG (MR-IMSRG), which is designed for the efficient calculation of nuclear ground-state properties. The second is the derivation of non-empirical valence-space interactions that can be used as input for nuclear shell model (i.e., configuration interaction (CI)) calculations. This IMSRG+shell model approach provides immediate access to excitation spectra, transitions, etc, but is limited in applicability by the factorial cost of the CI calculations. We review applications of the MR-IMSRG and IMSRG+shell model approaches to the calculation of ground-state properties for the oxygen, calcium, and nickel isotopic chains or the spectroscopy of nuclei in the lower sd shell, respectively, and present selected new results, e.g., for the ground- and excited state properties of neon isotopes.

Probing the Single-Particle Character of Rotational States in F 19 Using a Short-Lived Isomeric Beam

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

Santiago-Gonzalez, D.; Auranen, K.; Avila, M. L.

2018-03-01

A beam containing a substantial component of both the J(pi) = 5(+), T-1/2 = 162 ns isomeric state of F-18 and its 1(+), 109.77-min ground state is utilized to study members of the ground-state rotational band in F-19 through the neutron transfer reaction (d,p) in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13/2(+) band-terminating state. The agreement between shell-model calculations using an interaction constructed within the sd shell, and our experimental results reinforces the idea of a single-particle-collective duality in the descriptions of the structure of atomic nuclei.

Hearing results using the SMart piston prosthesis.

PubMed

Fayad, Jose N; Semaan, Maroun T; Meier, Josh C; House, John W

2009-12-01

SMart, a newly introduced piston prosthesis for stapedotomy, is a nitinol-based, heat-activated, self-crimping prosthesis. We review our hearing results and postoperative complications using this self-crimped piston prosthesis and compare them with those obtained using stainless steel or platinum piston prostheses. Audiometric results using the SMart piston are identical to those obtained using a conventional piston prosthesis. Retrospective chart review. Private neurotologic tertiary referral center. The 416 ears reviewed included 306 with a SMart prosthesis and 110 conventional prostheses. 61% were women. Mean follow-up time was 5.6 (standard deviation [SD], 6.3 mo) and 6.9 months (SD, 7.0 mo) for the 2 groups, respectively. Stapedotomy using the SMart or a conventional (non-SMart) prosthesis. Audiometric hearing results, including pure-tone average (PTA) and air-bone gap (ABG), and prevalence of postoperative complications. Mean postoperative PTA was 32.6 (SD, 16.8) dB for the SMart group and 29.4 (SD, 13.5) dB for the non-SMart group, with ABGs of 7.6 (SD, 8.9) and 6.0 (SD, 5.2) dB, respectively. Mean change (decrease) in ABG was 18.7 (SD, 13.1) dB for the SMart group and 19.9 (SD, 10.3) dB for the non-SMart group. High-frequency bone PTAs showed overclosure of 2.0 (SD, 7.9) dB for the SMart group and 3.6 (SD, 8.6) dB for the non-SMart group. Postoperative vertigo and tinnitus were infrequent. No significant differences in these audiometric outcomes or complication rates were noted between groups. There was no significant difference in rate of gap closure to within 10 dB (78.3 versus 84.2%, SMart and non-SMart, respectively) or 20 dB (94.2 and 98.0%). Compared with conventional stapes prostheses, the nitinol-based SMart is a safe and reliable stapes prosthesis that eliminates manual crimping without significantly altering the audiometric outcome. Complications are rare, but longer follow-up is needed before establishing long-term stability.

HIGH ENERGY GASEOUS DISCHARGE DEVICES

DOEpatents

Josephson, V.

1960-02-16

The high-energy electrical discharge device described comprises an envelope, a pair of main discharge electrodes supported in opposition in the envelope, and a metallic shell symmetrically disposed around and spaced from the discharge path between the electrodes. The metallic shell comprises a first element of spaced helical turns of metallic material and a second element of spaced helical turns of methllic material insulatedly supported in superposition outside the first element and with the turns overlapping the gap between the turns of the first element.

Joint and Interdependent Requirements: A Case Study in Solving the Naval Surface Fire Support Capabilities Gap

DTIC Science & Technology

2007-05-17

inch long ra projectiles against Viet Cong positions to ranges over 35 miles – 60,000 yards - inland. Additionally, a 5- inch rocket assisted projectile...ship. The 100 mile rocket assisted shell was approximately twenty inches too long to work within the existing handling system. The 278 mile rocket... assisted shell was fourteen inches too long for the Iowa class ship’s ammunition handling equi However, if shortened to seventy-six inches, this

Developing Test Apparatus and Measurements of AC Loss of High Temperature Superconductors

DTIC Science & Technology

2012-11-01

temperature of the coil is not raised significantly. The second system, a larger machine, designed with a long term prospective to serve a test bed for...four sample chambers inside the vacuum gap, LN2 – cooled sample holder (currently only one is in use), the laminated back iron, and the outer shell...machine. accommodate a variety of different small coils and linear tapes. This assembly is surrounded by the laminated back iron and the outer shell

Effect of core-shell structure on optical properties of Au-Cu2O nanoparticles

NASA Astrophysics Data System (ADS)

Sai, Cong Doanh; Ngac, An Bang

2018-03-01

Solid Au-Cu2O core-shell nanoparticles were synthesized using gold nanoparticles of 16.6 nm in size as the core. The core-shell structure of the synthesized particles was confirmed and characterized by TEM and HRTEM images. Due to their similar crystal structure, the (111) planes of Cu2O are nucleated and grown epitaxially on the {111} facets of Au nanoparticles with the lattice mismatch of about 4.3% resulting in a polycrystallized Cu2O shell covering the Au nanocore. Due to the quantum confinement effect, the band gap energy Eg of the synthesized Cu2O shells is blue-shifted from 2.35 to 2.70 eV as the shell thickness decreases from of 24.6±3.6 to 9.0±1.7 nm. The localized SPR (Surface Plasmon Resonance) peak of the Au nanocore undergoes a large red shift of the order of a hundred of nm due to both the high refractive index and the increase of the thickness of Cu2O shell. Theoretical models within the Drude framework significantly underestimate the experimental data and predict a wrong rate of change of the SPR peak position with respect to the shell thickness.

The Colletotrichum acutatum species complex

PubMed Central

Damm, U.; Cannon, P.F.; Woudenberg, J.H.C.; Crous, P.W.

2012-01-01

Colletotrichum acutatum is known as an important anthracnose pathogen of a wide range of host plants worldwide. Numerous studies have reported subgroups within the C. acutatum species complex. Multilocus molecular phylogenetic analysis (ITS, ACT, TUB2, CHS-1, GAPDH, HIS3) of 331 strains previously identified as C. acutatum and other related taxa, including strains from numerous hosts with wide geographic distributions, confirmed the molecular groups previously recognised and identified a series of novel taxa. Thirty-one species are accepted, of which 21 have not previously been recognised. Colletotrichum orchidophilum clusters basal to the C. acutatum species complex. There is a high phenotypic diversity within this complex, and some of the species appear to have preferences to specific hosts or geographical regions. Others appear to be plurivorous and are present in multiple regions. In this study, only C. salicis and C. rhombiforme formed sexual morphs in culture, although sexual morphs have been described from other taxa (especially as laboratory crosses), and there is evidence of hybridisation between different species. One species with similar morphology to C. acutatum but not belonging to this species complex was also described here as new, namely C. pseudoacutatum. Taxonomic novelties: New combinations - Colletotrichum limetticola (R.E. Clausen) Damm, P.F. Cannon & Crous, C. lupini (Bondar) Damm, P.F. Cannon & Crous, C. salicis (Fuckel) Damm, P.F. Cannon & Crous. New species - C. acerbum Damm, P.F. Cannon & Crous, C. australe Damm, P.F. Cannon & Crous, C. brisbanense Damm, P.F. Cannon & Crous, C. cosmi Damm, P.F. Cannon & Crous, C. costaricense Damm, P.F. Cannon & Crous, C. cuscutae Damm, P.F. Cannon & Crous, C. guajavae Damm, P.F. Cannon & Crous, C. indonesiense Damm, P.F. Cannon & Crous, C. johnstonii Damm, P.F. Cannon & Crous, C. kinghornii Damm, P.F. Cannon & Crous, C. laticiphilum Damm, P.F. Cannon & Crous, C. melonis Damm, P.F. Cannon & Crous, C. orchidophilum Damm, P.F. Cannon & Crous, C. paxtonii Damm, P.F. Cannon & Crous, C. pseudoacutatum Damm, P.F. Cannon & Crous C. pyricola Damm, P.F. Cannon & Crous, C. rhombiforme Damm, P.F. Cannon & Crous, C. scovillei Damm, P.F. Cannon & Crous, C. sloanei Damm, P.F. Cannon & Crous, C. tamarilloi Damm, P.F. Cannon & Crous, C. walleri Damm, P.F. Cannon & Crous. Typifications: Epitypifications - C. acutatum J.H. Simmonds, C. limetticola (R.E. Clausen) Damm, P.F. Cannon & Crous, C. nymphaeae (Pass.) Aa, C. phormii (Henn.) D.F. Farr & Rossman, C. salicis (Fuckel) Damm, P.F. Cannon & Crous. Lectotypifications - C. nymphaeae (Pass.) Aa, C. orchidearum Allesch. PMID:23136458

Prevalence and Antimicrobial Resistance of Enterobacteriaceae in Shell Eggs from Small-Scale Poultry Farms and Farmers' Markets.

PubMed

Kilonzo-Nthenge, A; Nahashon, S N; Godwin, S; Liu, S; Long, D

2016-12-01

Public health concerns over the emergence of antimicrobial resistant bacteria have increased recently. The purpose of this study was to investigate the prevalence of antimicrobial resistant Enterobacteriaceae in shell eggs purchased from small poultry farms and farmers' markets. A total of 504 eggs were pooled to make 252 composite samples, consisting of 2 eggs per composite. The microbial quality of shell eggs was determined by standard quantitative, biochemical, and PCR techniques. Susceptibility to 13 antimicrobial agents was determined by the Kirby-Bauer disk diffusion technique, and results were interpreted based on Clinical and Laboratory Standards Institute values. Shell eggs and egg contents were positive for Escherichia coli (11.9 and 5.2%, respectively), Enterobacter (9.1 and 7.9%), and Serratia (11.5 and 4.8%). Salmonella was isolated from 3.6% of egg shells but not from egg contents. Mean (±SD) Enterobacteriaceae levels (4.4 ± 2.0 log CFU per eggshell) on shell eggs from poultry farms was significantly higher (P ≤ 0.05) than that on shell eggs from farmers' markets (2.1 ± 1.3 log CFU per eggshell). Of the 134 isolates recovered, resistance among isolates from farm and market shell eggs to erythromycin was most common (48.5 and 32.8%, respectively) followed by ampicillin (44.8 and 17.2%), and tetracycline (29.9 and 17.2%). The multiple antibiotic resistance index value for E. coli and Pantoea was 0.62, and that for Salmonella and Klebsiella terrigena was 0.08, indicating that Enterobacteriaceae in shell eggs can be resistant to multiple antimicrobial agents. These data reveal that shell eggs from small poultry farms and farmers' markets can harbor antimicrobial resistant pathogenic and commensal bacteria. Thus, failure to properly handle shell eggs poses a potential health hazard to consumers.

Electrosprayed core–shell solid dispersions of acyclovir fabricated using an epoxy-coated concentric spray head

PubMed Central

Liu, Zhe-Peng; Cui, Lei; Yu, Deng-Guang; Zhao, Zhuan-Xia; Chen, Lan

2014-01-01

A novel structural solid dispersion (SD) taking the form of core–shell microparticles for poorly water-soluble drugs is reported for the first time. Using polyvinylpyrrolidone (PVP) as a hydrophilic polymer matrix, the SDs were fabricated using coaxial electrospraying (characterized by an epoxy-coated concentric spray head), although the core fluids were unprocessable using one-fluid electrospraying. Through manipulating the flow rates of the core drug-loaded solutions, two types of core–shell microparticles with tunable drug contents were prepared. They had average diameters of 1.36±0.67 and 1.74±0.58 μm, and were essentially a combination of nanocomposites with the active ingredient acyclovir (ACY) distributed in the inner core, and the sweeter sucralose and transmembrane enhancer sodium dodecyl sulfate localized in the outer shell. Differential scanning calorimetry and X-ray diffraction results demonstrated that ACY, sodium dodecyl sulfate, and sucralose were well distributed in the PVP matrix in an amorphous state because of favorable second-order interactions. In vitro dissolution and permeation studies showed that the core–shell microparticle SDs rapidly freed ACY within 1 minute and promoted nearly eightfold increases in permeation rate across the sublingual mucosa compared with raw ACY powders. PMID:24790437

In vitro, ex vivo and in vivo characterization of PLGA nanoparticles loading pranoprofen for ocular administration.

PubMed

Cañadas, Cristina; Alvarado, Helen; Calpena, Ana C; Silva, Amélia M; Souto, Eliana B; García, Maria L; Abrego, Guadalupe

2016-09-25

Pranoprofen (PF) is a NSAID considered as a safe anti-inflammatory treatment for strabismus and/or cataract surgery. The drug has been formulated in poly (lactic/glycolic) acid (PLGA) nanoparticles (PF-F1NPs with cPF 1.5mg/mL, PF-F2NPs with cPF 1mg/mL) produced by solvent displacement technique and tested the in vitro cytotoxicity, ex vivo corneal permeation, in vivo ocular tolerance and in vivo anti-inflammatory efficacy of PF-F1NPs, PF-F2NPs, in comparison to eye drops conventional dosage form (Oftalar(®), PF 1mg/mL) and free drug solution (PF dissolved in PBS, 1.5mg/mL). The mean particle size of both formulations was around 350nm, with polydispersity index below 0.1, and a net negative charge of -7.41mV and -8.5mV for PF-F1NPs and PF-F2NPs, respectively. Y-79 human retinoblastoma cell line was used to evaluate the cytotoxicity of PF-F1NPs and PF-F2NPs, which were compared to blank NPs and free drug solution (PF dissolved in PBS, 1.5mg/mL). Concentrations up to 75μg/mL exhibited no toxicity to Y-79 cells, whereas at 150μg/mL a decrease of about 80% on the cell viability was observed after exposing the cells to PF-F1NPs. When treating the Y-79 cells with concentrations of PF-F2NPs between 1μg/mL to 100μg/mL, the cell viability was similar to control values after 24h and 48h of exposure. An ex vivo corneal permeation study was carried out in New Zealand rabbits. A very similar profile has been observed for the permeation of PF through the cornea when administered as eye drops and as free drug solution, which was kept much lower in comparison to PF-NPs formulations. The permeated amount of PF from the PF-F1NPs was slightly smaller than from PF-F2NPs, attributed to the increase of viscosity of the formulations with the increase of cPVA concentration. New Zealand white rabbits were also used to evaluate the irritancy of PF-F1NPs and PF-F2NPs, which demonstrated to be well-tolerated to the eye (i.e. the mean total score (MTS) was 0). PF-F2NPs exhibited the highest QP (amounts of PF permeated in the cornea) and significantly reduced the ocular edema compared to the tested formulations. The QR (amounts of PF retained in the cornea) of the PF-F1NPs was greater than that obtained for PF-F2NPs. Copyright © 2016 Elsevier B.V. All rights reserved.

Higher Order π-Conjugated Polycyclic Hydrocarbons with Open-Shell Singlet Ground State: Nonazethrene versus Nonacene.

PubMed

Huang, Rui; Phan, Hoa; Herng, Tun Seng; Hu, Pan; Zeng, Wangdong; Dong, Shao-Qiang; Das, Soumyajit; Shen, Yongjia; Ding, Jun; Casanova, David; Wu, Jishan

2016-08-17

Higher order acenes (i.e., acenes longer than pentacene) and extended zethrenes (i.e., zethrenes longer than zethrene) are theoretically predicted to have an open-shell singlet ground state, and the radical character is supposed to increase with extension of molecular size. The increasing radical character makes the synthesis of long zethrenes and acenes very challenging, and so far, the longest reported zethrene and acene derivatives are octazethrene and nonacene, respectively. In addition, there is a lack of fundamental understanding of the differences between these two closely related open-shell singlet systems. In this work, we report the first synthesis of a challenging nonazethrene derivative, HR-NZ, and its full structural and physical characterizations including variable temperature NMR, ESR, SQUID, UV-vis-NIR absorption and electrochemical measurements. Compound HR-NZ has an open-shell singlet ground state with a moderate diradical character (y0 = 0.48 based on UCAM-B3LYP calculation) and a small singlet-triplet gap (ΔES-T = -5.2 kcal/mol based on SQUID data), thus showing magnetic activity at room temperature. It also shows amphoteric redox behavior, with a small electrochemical energy gap (1.33 eV). Its electronic structure and physical properties are compared with those of Anthony's nonacene derivative JA-NA and other zethrene derivatives. A more general comparison between higher order acenes and extended zethrenes was also conducted on the basis of ab initio electronic structure calculations, and it was found that zethrenes and acenes have very different spatial localization of the unpaired electrons. As a result, a faster decrease of singlet-triplet energy gap and a faster increase of radical character with increase of the number of benzenoid rings were observed in zethrene series. Our studies reveal that spatial localization of the frontier molecular orbitals play a very important role on the nature of radical character as well as the excitation energy.

In-gap corner states in core-shell polygonal quantum rings.

PubMed

Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

2017-01-10

We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.

In-gap corner states in core-shell polygonal quantum rings

NASA Astrophysics Data System (ADS)

Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

2017-01-01

We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.

Amplitude fluctuations driven by the density of electron pairs within nanosize granular structures inside strongly disordered superconductors: evidence for a shell-like effect.

PubMed

Ghosh, Sanjib; Mandal, Sudhansu S

2013-11-15

Motivated by the recent observation of the shell effect in a nanoscale pure superconductor by Bose et al. [Nat. Mater. 9, 550 (2010)], we explore the possible shell-like effect in a strongly disordered superconductor as it is known to produce nanosize superconducting puddles (SPs). We find a remarkable change in the texture of the pairing amplitudes that is responsible for forming the SP, upon monotonic tuning of the average electron density, , and keeping the disorder landscape unaltered. Both the spatially averaged pairing amplitude and the quasiparticle excitation gap oscillate with . This oscillation is due to a rapid change in the low-lying quasiparticle energy spectra and thereby a change in the shapes and positions of the SPs. We establish a correlation between the formation of SPs and the shell-like effect. The experimental consequences of our theory are also discussed.

Photocatalytic hydrogen generation from water under visible light using core/shell nano-catalysts.

PubMed

Wang, X; Shih, K; Li, X Y

2010-01-01

A microemulsion technique was employed to synthesize nano-sized photocatalysts with a core (CdS)/shell (ZnS) structure. The primary particles of the photocatalysts were around 10 nm, and the mean size of the catalyst clusters in water was about 100 nm. The band gaps of the catalysts ranged from 2.25 to 2.46 eV. The experiments of photocatalytic H(2) generation showed that the catalysts (CdS)(x)/(ZnS)(1-x) with x ranging from 0.1 to 1 were able to produce hydrogen from water photolysis under visible light. The catalyst with x=0.9 had the highest rate of hydrogen production. The catalyst loading density also influenced the photo-hydrogen production rate, and the best catalyst concentration in water was 1 g L(-1). The stability of the nano-catalysts in terms of size, morphology and activity was satisfactory during an extended test period for a specific hydrogen production rate of 2.38 mmol g(-1) L(-1) h(-1) and a quantum yield of 16.1% under visible light (165 W Xe lamp, lambda>420 nm). The results demonstrate that the (CdS)/(ZnS) core/shell nano-particles are a novel photo-catalyst for renewable hydrogen generation from water under visible light. This is attributable to the large band-gap ZnS shell that separates the electron/hole pairs generated by the CdS core and hence reduces their recombinations.

Structure and Formation Mechanism of Black TiO 2 Nanoparticles

DOE PAGES

Tian, Mengkun; Mahjouri-Samani, Masoud; Eres, Gyula; ...

2015-10-27

The remarkable properties of black TiO 2 are due to its disordered surface shell surrounding a crystalline core. However, the chemical composition and the atomic and electronic structure of the disordered shell and its relationship to the core remain poorly understood. Using advanced transmission electron microscopy methods, we show that the outermost layer of black TiO 2 nanoparticles consists of a disordered Ti 2O 3 shell. The measurements show a transition region that connects the disordered Ti 2O 3 shell to the perfect rutile core consisting first of four to five monolayers of defective rutile, containing clearly visible Ti interstitialmore » atoms, followed by an ordered reconstruction layer of Ti interstitial atoms. Our data suggest that this reconstructed layer presents a template on which the disordered Ti 2O 3 layers form by interstitial diffusion of Ti ions. In contrast to recent reports that attribute TiO 2 band-gap narrowing to the synergistic action of oxygen vacancies and surface disorder of nonspecific origin, our results point to Ti 2O 3, which is a narrow-band-gap semiconductor. In conclusion, as a stoichiometric compound of the lower oxidation state Ti 3+ it is expected to be a more robust atomic structure than oxygen-deficient TiO 2 for preserving and stabilizing Ti 3+ surface species that are the key to the enhanced photocatalytic activity of black TiO 2.« less

Is adapted measured resection superior to gap-balancing in determining femoral component rotation in total knee replacement?

PubMed

Luyckx, T; Peeters, T; Vandenneucker, H; Victor, J; Bellemans, J

2012-09-01

Obtaining a balanced flexion gap with correct femoral component rotation is one of the prerequisites for a successful outcome after total knee replacement (TKR). Different techniques for achieving this have been described. In this study we prospectively compared gap-balancing versus measured resection in terms of reliability and accuracy for femoral component rotation in 96 primary TKRs performed in 96 patients using the Journey system. In 48 patients (18 men and 30 women) with a mean age of 65 years (45 to 85) a tensor device was used to determine rotation. In the second group of 48 patients (14 men and 34 women) with a mean age of 64 years (41 to 86), an 'adapted' measured resection technique was used, taking into account the native rotational geometry of the femur as measured on a pre-operative CT scan. Both groups systematically reproduced a similar external rotation of the femoral component relative to the surgical transepicondylar axis: 2.4° (SD 2.5) in the gap-balancing group and 1.7° (SD 2.1) in the measured resection group (p = 0.134). Both gap-balancing and adapted measured resection techniques proved equally reliable and accurate in determining femoral component rotation after TKR. There was a tendency towards more external rotation in the gap-balancing group, but this difference was not statistically significant (p = 0.134). The number of outliers for our 'adapted' measured resection technique was much lower than reported in the literature.

Plasmodium falciparum Hop (PfHop) Interacts with the Hsp70 Chaperone in a Nucleotide-Dependent Fashion and Exhibits Ligand Selectivity.

PubMed

Zininga, Tawanda; Makumire, Stanely; Gitau, Grace Wairimu; Njunge, James M; Pooe, Ofentse Jacob; Klimek, Hanna; Scheurr, Robina; Raifer, Hartmann; Prinsloo, Earl; Przyborski, Jude M; Hoppe, Heinrich; Shonhai, Addmore

2015-01-01

Heat shock proteins (Hsps) play an important role in the development and pathogenicity of malaria parasites. One of the most prominent functions of Hsps is to facilitate the folding of other proteins. Hsps are thought to play a crucial role when malaria parasites invade their host cells and during their subsequent development in hepatocytes and red blood cells. It is thought that Hsps maintain proteostasis under the unfavourable conditions that malaria parasites encounter in the host environment. Although heat shock protein 70 (Hsp70) is capable of independent folding of some proteins, its functional cooperation with heat shock protein 90 (Hsp90) facilitates folding of some proteins such as kinases and steroid hormone receptors into their fully functional forms. The cooperation of Hsp70 and Hsp90 occurs through an adaptor protein called Hsp70-Hsp90 organising protein (Hop). We previously characterised the Hop protein from Plasmodium falciparum (PfHop). We observed that the protein co-localised with the cytosol-localised chaperones, PfHsp70-1 and PfHsp90 at the blood stages of the malaria parasite. In the current study, we demonstrated that PfHop is a stress-inducible protein. We further explored the direct interaction between PfHop and PfHsp70-1 using far Western and surface plasmon resonance (SPR) analyses. The interaction of the two proteins was further validated by co-immunoprecipitation studies. We observed that PfHop and PfHsp70-1 associate in the absence and presence of either ATP or ADP. However, ADP appears to promote the association of the two proteins better than ATP. In addition, we investigated the specific interaction between PfHop TPR subdomains and PfHsp70-1/ PfHsp90, using a split-GFP approach. This method allowed us to observe that TPR1 and TPR2B subdomains of PfHop bind preferentially to the C-terminus of PfHsp70-1 compared to PfHsp90. Conversely, the TPR2A motif preferentially interacted with the C-terminus of PfHsp90. Finally, we observed that recombinant PfHop occasionally eluted as a protein species of twice its predicted size, suggesting that it may occur as a dimer. We conducted SPR analysis which suggested that PfHop is capable of self-association in presence or absence of ATP/ADP. Overall, our findings suggest that PfHop is a stress-inducible protein that directly associates with PfHsp70-1 and PfHsp90. In addition, the protein is capable of self-association. The findings suggest that PfHop serves as a module that brings these two prominent chaperones (PfHsp70-1 and PfHsp90) into a functional complex. Since PfHsp70-1 and PfHsp90 are essential for parasite growth, findings from this study are important towards the development of possible antimalarial inhibitors targeting the cooperation of these two chaperones.

Observation of high-spin bands with large moments of inertia in Xe 124

DOE PAGES

Nag, Somnath; Singh, A. K.; Hagemann, G. B.; ...

2016-09-07

In this paper, high-spin states in 124Xe have been populated using the 80Se( 48Ca, 4n) reaction at a beam energy of 207 MeV and high-multiplicity, γ-ray coincidence events were measured using the Gammasphere spectrometer. Six high-spin rotational bands with moments of inertia similar to those observed in neighboring nuclei have been observed. The experimental results are compared with calculations within the framework of the Cranked Nilsson-Strutinsky model. Finally, it is suggested that the configurations of the bands involve excitations of protons across the Z = 50 shell gap coupled to neutrons within the N = 50 - 82 shell ormore » excited across the N = 82 shell closure.« less

A facile method for synthesis of well-coated ZnO@graphene core/shell structure by self-assembly of amine-functionalized ZnO and graphene oxide

NASA Astrophysics Data System (ADS)

Zhang, Yunlong; Song, Lixin; Zhang, Yuzhi; Wang, Panpan; Liu, Yangqiao; Wu, Lingnan; Zhang, Tao

2016-06-01

The core/shell structure was formed by GO self-assembled with amine-functionalized commercial ZnO (CZO) and preparative hexagonal ZnO (HZO), respectively. Graphene-coated CZO and HZO were obtained after being reduced in Ar at 500 °C. The mechanism of the coating procedure was investigated by measuring their respective zeta potential values. Our characterizations demonstrate that graphene on HZO has better quality and fewer layers. An obvious band gap decrease of ZnO was observed for coating with graphene. Photoluminescence spectra of ZnO@graphene core/shell composites display the fluorescence quenching property, which indicates its good application prospect in optoelectronics, photocatalytic and other fields.

Population genetic structure and natural selection of Plasmodium falciparum apical membrane antigen-1 in Myanmar isolates.

PubMed

Kang, Jung-Mi; Lee, Jinyoung; Moe, Mya; Jun, Hojong; Lê, Hương Giang; Kim, Tae Im; Thái, Thị Lam; Sohn, Woon-Mok; Myint, Moe Kyaw; Lin, Khin; Shin, Ho-Joon; Kim, Tong-Soo; Na, Byoung-Kuk

2018-02-07

Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is one of leading blood stage malaria vaccine candidates. However, genetic variation and antigenic diversity identified in global PfAMA-1 are major hurdles in the development of an effective vaccine based on this antigen. In this study, genetic structure and the effect of natural selection of PfAMA-1 among Myanmar P. falciparum isolates were analysed. Blood samples were collected from 58 Myanmar patients with falciparum malaria. Full-length PfAMA-1 gene was amplified by polymerase chain reaction and cloned into a TA cloning vector. PfAMA-1 sequence of each isolate was sequenced. Polymorphic characteristics and effect of natural selection were analysed with using DNASTAR, MEGA4, and DnaSP programs. Polymorphic nature and natural selection in 459 global PfAMA-1 were also analysed. Thirty-seven different haplotypes of PfAMA-1 were identified in 58 Myanmar P. falciparum isolates. Most amino acid changes identified in Myanmar PfAMA-1 were found in domains I and III. Overall patterns of amino acid changes in Myanmar PfAMA-1 were similar to those in global PfAMA-1. However, frequencies of amino acid changes differed by country. Novel amino acid changes in Myanmar PfAMA-1 were also identified. Evidences for natural selection and recombination event were observed in global PfAMA-1. Among 51 commonly identified amino acid changes in global PfAMA-1 sequences, 43 were found in predicted RBC-binding sites, B-cell epitopes, or IUR regions. Myanmar PfAMA-1 showed similar patterns of nucleotide diversity and amino acid polymorphisms compared to those of global PfAMA-1. Balancing natural selection and intragenic recombination across PfAMA-1 are likely to play major roles in generating genetic diversity in global PfAMA-1. Most common amino acid changes in global PfAMA-1 were located in predicted B-cell epitopes where high levels of nucleotide diversity and balancing natural selection were found. These results highlight the strong selective pressure of host immunity on the PfAMA-1 gene. These results have significant implications in understanding the nature of Myanmar PfAMA-1 along with global PfAMA-1. They also provide useful information for the development of effective malaria vaccine based on this antigen.

Electrostatic Estimation of Intercalant Jump-Diffusion Barriers Using Finite-Size Ion Models.

PubMed

Zimmermann, Nils E R; Hannah, Daniel C; Rong, Ziqin; Liu, Miao; Ceder, Gerbrand; Haranczyk, Maciej; Persson, Kristin A

2018-02-01

We report on a scheme for estimating intercalant jump-diffusion barriers that are typically obtained from demanding density functional theory-nudged elastic band calculations. The key idea is to relax a chain of states in the field of the electrostatic potential that is averaged over a spherical volume using different finite-size ion models. For magnesium migrating in typical intercalation materials such as transition-metal oxides, we find that the optimal model is a relatively large shell. This data-driven result parallels typical assumptions made in models based on Onsager's reaction field theory to quantitatively estimate electrostatic solvent effects. Because of its efficiency, our potential of electrostatics-finite ion size (PfEFIS) barrier estimation scheme will enable rapid identification of materials with good ionic mobility.

Investigation of the combined effect of MgO and PEG on the release profile of mefenamic acid prepared via hot-melt extrusion techniques.

PubMed

Alshehri, Sultan M; Tiwari, Roshan V; Alsulays, Bader B; Ashour, Eman A; Alshetaili, Abdullah S; Almutairy, Bjad; Park, Jun-Bom; Morott, Joseph; Sandhu, Bhupinder; Majumdar, Soumyajit; Repka, Michael A

2017-09-01

This study aimed to investigate the combined effect of magnesium oxide (MgO) as an alkalizer and polyethylene glycol (PEG) as a plasticizer and wetting agent in the presence of Kollidon® 12 PF and 17 PF polymer carriers on the release profile of mefenamic acid (MA), which was prepared via hot-melt extrusion technique. Various drug loads of MA and various ratios of the polymers, PEG 3350 and MgO were blended using a V-shell blender and extruded using a twin-screw extruder (16-mm Prism EuroLab, ThermoFisher Scientific, Carlsbad, CA) at different screw speeds and temperatures to prepare a solid dispersion system. Differential scanning calorimetry and X-ray diffraction data of the extruded material confirmed that the drug existed in the amorphous form, as evidenced by the absence of corresponding peaks. MgO and PEG altered the micro-environmental pH to be more alkaline (pH 9) and increased the hydrophilicity and dispersibility of the extrudates to enhance MA solubility and release, respectively. The in vitro release study demonstrated an immediate release for 2 h with more than 80% drug release within 45 min in matrices containing MgO and PEG in combination with polyvinylpyrrolidone when compared to the binary mixture, physical mixture and pure drug.

Spiral interface: A reinforcing mechanism for laminated composite materials learned from nature

NASA Astrophysics Data System (ADS)

Gao, Yang; Guo, Zhenbin; Song, Zhaoqiang; Yao, Haimin

2017-12-01

Helical structures are ubiquitous in nature at length scales of a wide range. In this paper, we studied a helical architecture called microscopic screw dislocation (μ-SD), which is prevalently present in biological laminated composites such as shells of mollusks P. placenta and nacre of abalone. Mechanical characterization indicated that μ-SDs can greatly enhance resistance to scratching. To shed light on the underlying reinforcing mechanisms, we systematically investigated the mechanical behaviors of μ-SD using theoretical modeling in combination with finite element simulation. Our analysis on an individual μ-SD showed that the failure of a μ-SD under tension involves the delamination of the prolonged spiral interface, giving rise to much higher toughness compared to those of the planar counterpart. The corporation of multiple μ-SDs was further investigated by analyzing the effect of μ-SD density on the mechanical reinforcement. It was found that higher areal density of μ-SD would lead to more improvement in toughness. However, the operation of such reinforcing mechanism of μ-SD requires proclivity of cracking along the spiral interface, which is not spontaneous but conditional. Fracture mechanics-based modeling indicated that the proclivity of crack propagation along the spiral interface can be ensured if the fracture toughness of the interface is less than 60% of that of the lamina material. These findings not only uncover the reinforcing mechanisms of μ-SDs in biological materials but imply a great promise of applying μ-SDs in reinforcing synthetic laminated composites.

Effect of Slag-Steel Reaction on the Initial Solidification of Molten Steel during Continuous Casting

NASA Astrophysics Data System (ADS)

Wang, Wanlin; Lou, Zhican; Zhang, Haihui

2018-03-01

With the mold simulator technique, the effect of slag-steel reaction on the initial shell solidification as well as the heat transfer and lubrication behavior of the infiltrated mold/shell slag film was studied in this article. The results showed that the Al2O3 content, the CaO/SiO2 ratio, and the viscosity of mold flux were increased with the progress of the slag-steel reaction during casting. The slag-steel reaction has two major effects on the initial shell solidification: one is increasing the mold heat flux and shell thickness by the decrease of slag film thickness. The other is the reduction of mold heat flux by the increase of crystal fraction in slag film. Mold flux with a lower basicity, viscosity, and crystallization temperature would result in a larger liquid slag consumption and the uneven infiltration of slag into the mold and shell gap that eventually leads to the irregular solidification of initial shell with a poor surface quality, such as slag entrapment and depressions as well as glaciation marks. Conversely, mold flux with a higher viscosity, basicity, and crystallization temperature would result in a smaller liquid slag consumption, which would cause the poor mold lubrication, the longitudinal shell surface defects, and drag marks.

Effect of Slag-Steel Reaction on the Initial Solidification of Molten Steel during Continuous Casting

NASA Astrophysics Data System (ADS)

Wang, Wanlin; Lou, Zhican; Zhang, Haihui

2018-06-01

With the mold simulator technique, the effect of slag-steel reaction on the initial shell solidification as well as the heat transfer and lubrication behavior of the infiltrated mold/shell slag film was studied in this article. The results showed that the Al2O3 content, the CaO/SiO2 ratio, and the viscosity of mold flux were increased with the progress of the slag-steel reaction during casting. The slag-steel reaction has two major effects on the initial shell solidification: one is increasing the mold heat flux and shell thickness by the decrease of slag film thickness. The other is the reduction of mold heat flux by the increase of crystal fraction in slag film. Mold flux with a lower basicity, viscosity, and crystallization temperature would result in a larger liquid slag consumption and the uneven infiltration of slag into the mold and shell gap that eventually leads to the irregular solidification of initial shell with a poor surface quality, such as slag entrapment and depressions as well as glaciation marks. Conversely, mold flux with a higher viscosity, basicity, and crystallization temperature would result in a smaller liquid slag consumption, which would cause the poor mold lubrication, the longitudinal shell surface defects, and drag marks.

Science Achievement Gaps by Gender and Race/Ethnicity in Elementary and Middle School: Trends and Predictors

ERIC Educational Resources Information Center

Quinn, David M.; Cooc, North

2015-01-01

Research on science achievement disparities by gender and race/ethnicity often neglects the beginning of the pipeline in the early grades. We address this limitation using nationally representative data following students from Grades 3 to 8. We find that the Black-White science test score gap (-1.07 SD in Grade 3) remains stable over these years,…

A Chimeric Plasmodium falciparum Merozoite Surface Protein Vaccine Induces High Titers of Parasite Growth Inhibitory Antibodies

PubMed Central

Alaro, James R.; Partridge, Andrea; Miura, Kazutoyo; Diouf, Ababacar; Lopez, Ana M.; Angov, Evelina; Long, Carole A.

2013-01-01

The C-terminal 19-kDa domain of Plasmodium falciparum merozoite surface protein 1 (PfMSP119) is an established target of protective antibodies. However, clinical trials of PfMSP142, a leading blood-stage vaccine candidate which contains the protective epitopes of PfMSP119, revealed suboptimal immunogenicity and efficacy. Based on proof-of-concept studies in the Plasmodium yoelii murine model, we produced a chimeric vaccine antigen containing recombinant PfMSP119 (rPfMSP119) fused to the N terminus of P. falciparum merozoite surface protein 8 that lacked its low-complexity Asn/Asp-rich domain, rPfMSP8 (ΔAsn/Asp). Immunization of mice with the chimeric rPfMSP1/8 vaccine elicited strong T cell responses to conserved epitopes associated with the rPfMSP8 (ΔAsn/Asp) fusion partner. While specific for PfMSP8, this T cell response was adequate to provide help for the production of high titers of antibodies to both PfMSP119 and rPfMSP8 (ΔAsn/Asp) components. This occurred with formulations adjuvanted with either Quil A or with Montanide ISA 720 plus CpG oligodeoxynucleotide (ODN) and was observed in both inbred and outbred strains of mice. PfMSP1/8-induced antibodies were highly reactive with two major alleles of PfMSP119 (FVO and 3D7). Of particular interest, immunization with PfMSP1/8 elicited higher titers of PfMSP119-specific antibodies than a combined formulation of rPfMSP142 and rPfMSP8 (ΔAsn/Asp). As a measure of functionality, PfMSP1/8-specific rabbit IgG was shown to potently inhibit the in vitro growth of blood-stage parasites of the FVO and 3D7 strains of P. falciparum. These data support the further testing and evaluation of this chimeric PfMSP1/8 antigen as a component of a multivalent vaccine for P. falciparum malaria. PMID:23897613

Reptilia: Testudines: Emydidae Graptemys gibbonsi - Pascagoula Map Turtle

USGS Publications Warehouse

Lovich, Jeffrey E.; Ennen, Joshua R.

2014-01-01

The Pascagoula Map Turtle, Graptemys gibbonsi, is a large riverine species that exhibits pronounced sexual dimorphism, where females attain a maximum carapace length (CL) of 295 mm and males a maximum of 141 mm (Lovich et al. 2009). Mean adult female CL (248 mm) can be well over twice the mean CL of adult males (104 mm; Gibbons and Lovich 1990, Lovich et al. 2009). In addition, females have conspicuously enlarged heads (37.9 mm, SD = 14.0 mm) with broad alveolar surfaces (12.1 mm, SD = 4.9) compared to males (head width – 16.4 mm, SD = 1.1 mm; alveolar width – 4.3 mm, SD = 0.40 mm; Lindeman, unpublished data). Males have longer tails with the vent posterior to the edge of the carapace. Both sexes have relatively flat plastrons. Similar to other species within the pulchra clade, Graptemys gibbonsi possess a high-domed shell with a median keel. The median carapace keel is composed of prominent spines on the posterior portions of the second and third vertebrals. A broken black stripe, most pronounced anteriorly, marks the median keel of the vertebrals, and pleural scutes 1– 3 have a network of intersecting yellow lines or circular yellow markings on the distal parts. The plastron is pale yellow with dark pigment on some seams. Ground color of the head and limbs is brown to olive with light yellow or yellowish-green stripes and blotches. The yellow pigment on the upper marginal scutes is wide in comparison to other members of the pulchra clade.Hatchling pigmentation patterns resemble those of adults, but with more conspicuous patterns on the pleural scutes. Similarly, the plastron of hatchlings commonly has more dark pigmentation along the seams than adults. The shell is highly serrated along the edge of the carapace and the vertebral keel is more pronounced than in adults.

Interaction of apicoplast-encoded elongation factor (EF) EF-Tu with nuclear-encoded EF-Ts mediates translation in the Plasmodiumfalciparum plastid.

PubMed

Biswas, Subir; Lim, Erin E; Gupta, Ankit; Saqib, Uzma; Mir, Snober S; Siddiqi, Mohammad Imran; Ralph, Stuart A; Habib, Saman

2011-03-01

Protein translation in the plastid (apicoplast) of Plasmodium spp. is of immense interest as a target for potential anti-malarial drugs. However, the molecular data on apicoplast translation needed for optimisation and development of novel inhibitors is lacking. We report characterisation of two key translation elongation factors in Plasmodium falciparum, apicoplast-encoded elongation factor PfEF-Tu and nuclear-encoded PfEF-Ts. Recombinant PfEF-Tu hydrolysed GTP and interacted with its presumed nuclear-encoded partner PfEF-Ts. The EF-Tu inhibitor kirromycin affected PfEF-Tu activity in vitro, indicating that apicoplast EF-Tu is indeed the target of this drug. The predicted PfEF-Ts leader sequence targeted GFP to the apicoplast, confirming that PfEF-Ts functions in this organelle. Recombinant PfEF-Ts mediated nucleotide exchange on PfEF-Tu and homology modeling of the PfEF-Tu:PfEF-Ts complex revealed PfEF-Ts-induced structural alterations that would expedite GDP release from PfEF-Tu. Our results establish functional interaction between two apicoplast translation factors encoded by genes residing in different cellular compartments and highlight the significance of their sequence/structural differences from bacterial elongation factors in relation to inhibitor activity. These data provide an experimental system to study the effects of novel inhibitors targeting PfEF-Tu and PfEF-Tu.PfEF-Ts interaction. Our finding that apicoplast EF-Tu possesses chaperone-related disulphide reductase activity also provides a rationale for retention of the tufA gene on the plastid genome. Copyright © 2010 Australian Society for Parasitology Inc. All rights reserved.

Pharmacological modulation of spreading depolarizations.

PubMed

Sánchez-Porras, Renán; Zheng, Zelong; Sakowitz, Oliver W

2015-01-01

Spreading depolarization (SD) is a wave of almost complete depolarization of the neuronal and glial cells. Nowadays there is sufficient evidence demonstrating its pathophysiological effect in migraine with aura, transient global amnesia, stroke, subarachnoid hemorrhage, intracerebral hemorrhage, and traumatic brain injury. In these cases, occurrence of SD has been associated with functional neuronal damage, neuronal necrosis, neurological degeneration, and poor clinical outcome. Animal models show that SD can be modulated by drugs that interfere with its initiation and propagation. There are many pharmacological targets that may help to suppress SD occurrence, such as Na⁺, K⁺, Cl⁻, and Ca²⁺ channels; Na⁺/K⁺ -ATPase; gap junctions; and ligand-based receptors, for example, adrenergic, serotonin, sigma-1, calcitonin gene-related peptide, GABAA, and glutamate receptors. In this regard, N-methyl-d-aspartate (NMDA) receptor blockers, in particular, ketamine, have shown promising results. Therefore, theoretically pharmacologic modulation of SD could help diminish its pathological effects.

The Hippo effector Yorkie controls normal tissue growth by antagonizing scalloped-mediated default repression.

PubMed

Koontz, Laura M; Liu-Chittenden, Yi; Yin, Feng; Zheng, Yonggang; Yu, Jianzhong; Huang, Bo; Chen, Qian; Wu, Shian; Pan, Duojia

2013-05-28

The Hippo tumor suppressor pathway restricts tissue growth by inactivating the transcriptional coactivator Yki. Although Sd has been implicated as a DNA-binding transcription factor partner for Yki and can genetically account for gain-of-function Yki phenotypes, how Yki regulates normal tissue growth remains a long-standing puzzle because Sd, unlike Yki, is dispensable for normal growth in most Drosophila tissues. Here we show that the yki mutant phenotypes in multiple developmental contexts are rescued by inactivation of Sd, suggesting that Sd functions as a default repressor and that Yki promotes normal tissue growth by relieving Sd-mediated default repression. We further identify Tgi as a cofactor involved in Sd's default repressor function and demonstrate that the mammalian ortholog of Tgi potently suppresses the YAP oncoprotein in transgenic mice. These findings fill a major gap in Hippo-mediated transcriptional regulation and open up possibilities for modulating the YAP oncoprotein in cancer and regenerative medicine. Copyright © 2013 Elsevier Inc. All rights reserved.

Continuum and three-nucleon force effects on Be 9 energy levels

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

Langhammer, Joachim; Navrátil, Petr; Quaglioni, Sofia

2015-02-05

In this paper, we extend the recently proposed ab initio no-core shell model with continuum to include three-nucleon (3N) interactions beyond the few-body domain. The extended approach allows for the assessment of effects of continuum degrees of freedom as well as of the 3N force in ab initio calculations of structure and reaction observables of p- and lower-sd-shell nuclei. As a first application we concentrate on energy levels of the 9Be system for which all excited states lie above the n- 8Be threshold. For all energy levels, the inclusion of the continuum significantly improves the agreement with experiment, which wasmore » an issue in standard no-core shell model calculations. Furthermore, we find the proper treatment of the continuum indispensable for reliable statements about the quality of the adopted 3N interaction from chiral effective field theory. Finally, in particular, we find the 1/2 + resonance energy, which is of astrophysical interest, in good agreement with experiment.« less

In-gap corner states in core-shell polygonal quantum rings

PubMed Central

Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

2017-01-01

We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states. PMID:28071750

Seeking and sharing: why the pulmonary fibrosis community engages the web 2.0 environment.

PubMed

Albright, Karen; Walker, Tarik; Baird, Susan; Eres, Linda; Farnsworth, Tara; Fier, Kaitlin; Kervitsky, Dolly; Korn, Marjorie; Lederer, David J; McCormick, Mark; Steiner, John F; Vierzba, Thomas; Wamboldt, Frederick S; Swigris, Jeffrey J

2016-01-12

Pulmonary fibrosis (PF) is a rare, progressive disease that affects patients and their loved ones on many levels. We sought to better understand the needs and interests of PF patients and their loved ones (collectively "reader-participants") by systematically analyzing their engagement with the World Wide Web (the current version referred to as Web 2.0). Data were collected from three PF-focused, interactive websites hosted by physician-investigators with expertise in PF. All data generated by reader-participants for approximately 10 months were downloaded and then analyzed using qualitative content analysis methods. PF experts posted 38 blog entries and reader-participants posted 40 forum entries. Blogs received 363 responses, and forum entries received 108 responses from reader-participants. Reader-participants primarily used the three websites to seek information from or offer a contribution to the PF community. Information was sought about PF symptoms, diagnosis, prognosis, treatments, research, pathophysiology, and disease origin; reader-participants also made requests for new posts and pleas for research and sought clarification on existing content. Contributions included personal narratives about experiences with PF, descriptions of activities or behaviors found to be helpful with PF symptoms, resources or information about PF, and supportive comments to other PF sufferers. PF patients and their loved ones engage the Web 2.0 environment at these PF-focused sites to satisfy their needs to better understand PF and its impacts and to support others facing similar challenges. Clinicians may find it beneficial to encourage PF patients' involvement in internet forums that foster dynamic, bi-directional information sharing.

Computational reconstruction and fluid dynamics of in vivo thrombi from the microcirculation

NASA Astrophysics Data System (ADS)

Mirramezani, Mehran; Tomaiuolo, Maurizio; Stalker, Timothy; Shadden, Shawn

2016-11-01

Blood flow and mass transfer can have significant effects on clot growth, composition and stability during the hemostatic response. We integrate in vivo data with CFD to better understand transport processes during clot formation. By utilizing electron microscopy, we reconstructed the 3D thrombus structure formed after a penetrating laser injury in a mouse cremaster muscle. Random jammed packing is used to reconstruct the microenvironment of the platelet aggregate, with platelets modeled as ellipsoids. In our 3D model, Stokes flow is simulated to obtain the velocity field in the explicitly meshed gaps between platelets and the lumen surrounding the thrombus. Based on in vivo data, a clot is composed of a core of highly activated platelets covered by a shell of loosely adherent platelets. We studied the effects of clot size (thrombus growth), gap distribution (consolidation), and vessel blood flow rate on mean intrathrombus velocity. The results show that velocity is smaller in the core as compared to the shell, potentially enabling higher concentration of agonists in the core contributing to its activation. In addition, our results do not appear to be sensitive to the geometry of the platelets, but rather gap size plays more important role on intrathrombus velocity and transport.

Democratization as a United States Strategy for Middle East Security

DTIC Science & Technology

2005-03-18

the Middle East presents a wide variety of governments across the region. Republics exists in Algeria, Egypt, Lebanon , Syria, Tunisia, and Yemen...PF 4 5 PF 4 5 PF 4 5 PF 4 5 PF Lebanon 6 5 NF 6 5 NF 6 5 NF 6 5 NF 6 5 NF Libya 7 7 NF 7 7 NF 7 7 NF 7 7 NF 7 7 NF Morocco 5 4 PF 5 5 PF 5 5 PF 5 5...more open discussion of previously taboo topics.17 Syria’s firm control continues to be the greatest impediment to freedom in Lebanon . The Lebanese

A small size 1-3 atm pulsed CO2 laser with series-connected spark gaps ultraviolet preionization.

PubMed

Silakhori, K; Jelvani, S; Ghanavati, F; Sajad, B; Talebi, M; Sadr, M R

2014-01-01

A small size pulsed CO2 laser with rounded edge flat profiled electrodes and variable gas pressure in 1-3 atm range has been constructed and characterized. The perionization system consists of a pair of 16 series-connected spark gaps located along either side of the main electrodes by which, the number of required preionization capacitors is reduced to 4. Sharpening of the main discharge has been performed using a 300 pF peaking capacitor. A maximum energy of 160 mJ/pulse was obtained for CO2:N2:He≡1:1:8 gas mixture and 33 kV discharge voltage. By increasing the laser gas pressure in 1-3 atm range, the duration of spike and tail parts of the laser pulses have been reduced from 110 ns and 4 μs to 37 ns and 1 μs, respectively.

Risk factors and outcomes of postoperative pancreatic fistula after pancreatico-duodenectomy: an audit of 532 consecutive cases.

PubMed

Fu, Shun-Jun; Shen, Shun-Li; Li, Shao-Qiang; Hu, Wen-Jie; Hua, Yun-Peng; Kuang, Ming; Liang, Li-Jian; Peng, Bao-Gang

2015-03-26

Pancreatic fistula (PF) remains the most challenging complication after pancreaticoduodenectomy (PD). The purpose of this study was to identify the risk factors of PF and delineate its impact on patient outcomes. We retrospectively reviewed clinical data of 532 patients who underwent PD and divided them into PF group and no PF group. Risk factors and outcomes of PF following PD were examined. PF was found in 65 (12.2%) cases, of whom 11 were classified into ISGPF grade A, 42 grade B, and 12 grade C. Clinically serious postoperative complications in the PF versus no PF group were mortality, abdominal bleeding, bile leak, intra-abdominal abscess and pneumonia. Univariate and multivariate analysis showed that blood loss ≥ 500 ml, pancreatic duct diameter ≤ 3 mm and pancreaticojejunostomy type were independent risk factors of PF after PD. Blood loss ≥ 500 ml, pancreatic duct diameter ≤ 3 mm and pancreatico-jejunostomy type were independent risk factors of PF after PD. PF was related with higher mortality rate, longer hospital stay, and other complications.

Enhanced Oral Bioavailability of Pueraria Flavones by a Novel Solid Self-microemulsifying Drug Delivery System (SMEDDS) Dropping Pills.

PubMed

Guan, Qingxiang; Zhang, Guangyuan; Sun, Shilin; Fan, Hongbo; Sun, Cheng; Zhang, Shaoyuan

2016-05-01

To improve bioavailability of pueraria flavones (PF), a self-microemulsifying drug delivery system (SMEDDS) dropping pills composed of PF, Crodamol GTCC, Maisine 35-1, Cremophor RH 40, 1,2-propylene glycol and polyethylene glycol 6000 (PEG6000) was developed. Particle size, zeta potential, morphology and in vitro drug release were investigated, respectively. Pharmacokinetics, bioavailability of PF-SMEDDS dropping pills and commercial Yufengningxin dropping pills were also evaluated and compared in rats. Puerarin treated as the representative component of PF was analyzed. Dynamic light scattering showed the ability of PF-SMEDDS dropping pills to form a nanoemulsion droplet size in aqueous media. The type of media showed no significant effects on the release rate of PF. PF-SMEDDS dropping pills were able to improve the in vitro release rate of PF, and the in vitro release of these dropping pills was significantly faster than that of Yufengningxin dropping pills. There was a dramatic difference between the mean value of t1/2, peak concentration (Cmax), the area of concentration-time curve from 0 to 6 h (AUC0-6 h) of PF-SMEDDS dropping pills and that of commercial Yufengningxin dropping pills. A pharmacokinetic study showed that the bioavailability of PF was greatly enhanced by PF-SMEDDS dropping pills. The value of Cmax and relative bioavailability of PF-SMEDDS dropping pills were dramatically improved by an average of 1.69- and 2.36-fold compared with that of Yufengningxin dropping pills after gavage administration, respectively. It was concluded that bioavailability of PF was greatly improved and that PF-SMEDDS dropping pills might be an encouraging strategy to enhance the oral bioavailability of PF.

Excitons in Core-Shell Nanowires with Polygonal Cross Sections.

PubMed

Sitek, Anna; Urbaneja Torres, Miguel; Torfason, Kristinn; Gudmundsson, Vidar; Bertoni, Andrea; Manolescu, Andrei

2018-04-11

The distinctive prismatic geometry of semiconductor core-shell nanowires leads to complex localization patterns of carriers. Here, we describe the formation of optically active in-gap excitonic states induced by the interplay between localization of carriers in the corners and their mutual Coulomb interaction. To compute the energy spectra and configurations of excitons created in the conductive shell, we use a multielectron numerical approach based on the exact solution of the multiparticle Hamiltonian for electrons in the valence and conduction bands, which includes the Coulomb interaction in a nonperturbative manner. We expose the formation of well-separated quasidegenerate levels, and focus on the implications of the electron localization in the corners or on the sides of triangular, square, and hexagonal cross sections. We obtain excitonic in-gap states associated with symmetrically distributed electrons in the spin singlet configuration. They acquire large contributions due to Coulomb interaction, and thus are shifted to much higher energies than other states corresponding to the conduction electron and the vacancy localized in the same corner. We compare the results of the multielectron method with those of an electron-hole model, and we show that the latter does not reproduce the singlet excitonic states. We also obtain the exciton lifetime and explain selection rules which govern the recombination process.

Governance of Offshore IT Outsourcing at Shell Global Functions IT-BAM Development and Application of a Governance Framework to Improve Outsourcing Relationships

NASA Astrophysics Data System (ADS)

de Jong, Floor; van Hillegersberg, Jos; van Eck, Pascal; van der Kolk, Feiko; Jorissen, Rene

The lack of effective IT governance is widely recognized as a key inhibitor to successful global IT outsourcing relationships. In this study we present the development and application of a governance framework to improve outsourcing relationships. The approach used to developing an IT governance framework includes a meta model and a customization process to fit the framework to the target organization. The IT governance framework consists of four different elements (1) organisational structures, (2) joint processes between in- and outsourcer, (3) responsibilities that link roles to processes and (4) a diverse set of control indicators to measure the success of the relationship. The IT governance framework is put in practice in Shell GFIT BAM, a part of Shell that concluded to have a lack of management control over at least one of their outsourcing relationships. In a workshop the governance framework was used to perform a gap analysis between the current and desired governance. Several gaps were identified in the way roles and responsibilities are assigned and joint processes are set-up. Moreover, this workshop also showed the usefulness and usability of the IT governance framework in structuring, providing input and managing stakeholders in the discussions around IT governance.

High mobility group box (HMGB) proteins of Plasmodium falciparum: DNA binding proteins with pro-inflammatory activity.

PubMed

Kumar, Krishan; Singal, Ankita; Rizvi, M Moshahid A; Chauhan, Virander S

2008-06-01

High mobility group box chromosomal protein 1 (HMGB1), known as an abundant, non-histone architectural chromosomal protein, is highly conserved across different species. Homologues of HMGB1 were identified and cloned from malaria parasite, Plasmodium falciparum. Sequence analyses showed that the P. falciparum HMGB1 (PfHMGB1) exhibits 45, 23 and 18%, while PfHMGB2 shares 42, 21 and 17% homology with Saccharomyces cerevisiae, human and mouse HMG box proteins respectively. Parasite PfHMGB1and PfHMGB2 proteins contain one HMG Box domain similar to B-Box of mammalian HMGB1. Electrophoretic Mobility Shift Assay (EMSA) showed that recombinant PfHMGB1 and PfHMGB2 bind to DNA. Immunofluorescence Assay using specific antibodies revealed that these proteins are expressed abundantly in the ring stage nuclei. Significant levels of PfHMGB1 and PfHMGB2 were also present in the parasite cytosol at trophozoite and schizont stages. Both, PfHMGB1 and PfHMGB2 were found to be potent inducers of pro-inflammatory cytokines such as TNFalpha from mouse peritoneal macrophages as analyzed by both reverse transcription PCR and by ELISA. These results suggest that secreted PfHMGB1 and PfHMGB2 may be responsible for eliciting/ triggering host inflammatory immune responses associated with malaria infection.

Sterile protection against human malaria by chemoattenuated PfSPZ vaccine.

PubMed

Mordmüller, Benjamin; Surat, Güzin; Lagler, Heimo; Chakravarty, Sumana; Ishizuka, Andrew S; Lalremruata, Albert; Gmeiner, Markus; Campo, Joseph J; Esen, Meral; Ruben, Adam J; Held, Jana; Calle, Carlos Lamsfus; Mengue, Juliana B; Gebru, Tamirat; Ibáñez, Javier; Sulyok, Mihály; James, Eric R; Billingsley, Peter F; Natasha, K C; Manoj, Anita; Murshedkar, Tooba; Gunasekera, Anusha; Eappen, Abraham G; Li, Tao; Stafford, Richard E; Li, Minglin; Felgner, Phil L; Seder, Robert A; Richie, Thomas L; Sim, B Kim Lee; Hoffman, Stephen L; Kremsner, Peter G

2017-02-23

A highly protective malaria vaccine would greatly facilitate the prevention and elimination of malaria and containment of drug-resistant parasites. A high level (more than 90%) of protection against malaria in humans has previously been achieved only by immunization with radiation-attenuated Plasmodium falciparum (Pf) sporozoites (PfSPZ) inoculated by mosquitoes; by intravenous injection of aseptic, purified, radiation-attenuated, cryopreserved PfSPZ ('PfSPZ Vaccine'); or by infectious PfSPZ inoculated by mosquitoes to volunteers taking chloroquine or mefloquine (chemoprophylaxis with sporozoites). We assessed immunization by direct venous inoculation of aseptic, purified, cryopreserved, non-irradiated PfSPZ ('PfSPZ Challenge') to malaria-naive, healthy adult volunteers taking chloroquine for antimalarial chemoprophylaxis (vaccine approach denoted as PfSPZ-CVac). Three doses of 5.12 × 10 4 PfSPZ of PfSPZ Challenge at 28-day intervals were well tolerated and safe, and prevented infection in 9 out of 9 (100%) volunteers who underwent controlled human malaria infection ten weeks after the last dose (group III). Protective efficacy was dependent on dose and regimen. Immunization with 3.2 × 10 3 (group I) or 1.28 × 10 4 (group II) PfSPZ protected 3 out of 9 (33%) or 6 out of 9 (67%) volunteers, respectively. Three doses of 5.12 × 10 4 PfSPZ at five-day intervals protected 5 out of 8 (63%) volunteers. The frequency of Pf-specific polyfunctional CD4 memory T cells was associated with protection. On a 7,455 peptide Pf proteome array, immune sera from at least 5 out of 9 group III vaccinees recognized each of 22 proteins. PfSPZ-CVac is a highly efficacious vaccine candidate; when we are able to optimize the immunization regimen (dose, interval between doses, and drug partner), this vaccine could be used for combination mass drug administration and a mass vaccination program approach to eliminate malaria from geographically defined areas.

Effects of 17β-estradiol on the release of monocyte chemotactic protein-1 and MAPK activity in monocytes stimulated with peritoneal fluid from endometriosis patients.

PubMed

Lee, Dong-Hyung; Kim, Seung-Chul; Joo, Jong-Kil; Kim, Hwi-Gon; Na, Young-Jin; Kwak, Jong-Young; Lee, Kyu-Sup

2012-03-01

Hormones and inflammation have been implicated in the pathological process of endometriosis; therefore, we investigated the combined effects of 17β-estradiol (E2) and peritoneal fluid obtained from patients with endometriosis (ePF) or a control peritoneal fluid (cPF) obtained from patients without endometriosis on the release of monocyte chemotactic protein-1 (MCP-1) by monocytes and the role of signaling pathways. Monocytes were cultured with ePF and cPF in the presence of E2; the MCP-1 levels in the supernatants were then measured by ELISA. In addition, mitogen activated protein kinase (MAPK) activation was measured by Western blotting of phosphorylated proteins. E2 down-regulated MCP-1 release by lipopolysaccharide- or cPF-treated monocytes, but failed to suppress its release by ePF-treated monocytes. The release of MCP-1 by ePF- and cPF-treated monocytes was efficiently abrogated by p38 mitogen activated protein kinase (MAPK) inhibitors; however, the MCP-1 release by cPF-treated monocytes, but not by ePF-treated monocytes, was blocked by a MAPK kinase inhibitor. In addition, ePF and cPF induced the phosphorylation of extracellular stress regulated kinase (ERK)1/2, p38 MAPK and c-Jun N-terminal kinase (JNK). E2 decreased the phosphorylation of p38 MAPK, but not ERK1/2 in ePF-treated monocytes; however, E2 decreased the phosphorylation of p38 MAPK, ERK1/2 and JNK in cPF-treated monocytes. The ability of E2 to modulate MCP-1 production is impaired in ePF-treated monocytes, which may be related to regulation of MAPK activity. These findings suggest that the failure of E2 to suppress ePF-treated production of MCP-1 may be involved in the pathogenesis of endometriosis. © 2012 The Authors. Journal of Obstetrics and Gynaecology Research © 2012 Japan Society of Obstetrics and Gynecology.

The Pavlovian power of palatable food: lessons for weight-loss adherence from a new rodent model of cue-induced overeating

PubMed Central

Boggiano, M M; Dorsey, J R; Thomas, J M; Murdaugh, D L

2009-01-01

Objective Relapsing to overeating is a stubborn problem in obesity treatment. We tested the hypothesis that context cues surrounding palatable food (PF) intake have the power to disrupt caloric regulation even of less PF. Context cues are non-food cues that are in the environment where PF is habitually eaten. Design Rats were conditioned to associate intake of Oreo cookies as the PF to cages with distinct context cues that differed from cues in cages were they were only given chow. PF naturally stimulated greater caloric intake. The rats were then tested in the PF cage with only chow available to determine if the PF-paired cues, alone, could elicit overeating of plain chow. Subjects Non food-deprived female Sprague-Dawley rats. Measurements Intake of plain chow under PF-paired cues vs. chow-paired cues was compared. This was also measured in tests that included a morsel of PF as a priming stimulus. We also controlled for any effect of binge-prone vs. binge–resistant status to predict cued-overeating. Results Rats consumed significantly more chow when exposed to context cues previously paired with PF than with chow (p<0.01). This effect occurred using various cues (e.g., different types of bedding or wallpaper). The effect was strengthened by priming with a morsel of PF (p<0.001) and was unaffected by baseline differences in propensity to binge on PF. Conclusion Context-cues associated with PF intake can drive overeating even of a less PF and abolish the ability of rats to compensate for the calories of a PF primer. Just as drug-associated context cues can reinstate drug-addiction relapse, PF-paired cues may trigger overeating relapses linked to weight regain and obesity. This model should help identify the reflex-like biology that sabotages attempts to adhere to healthy reduced calorie regimens and call greater attention to the cue-factor in the treatment of binge-eating and obesity. PMID:19350040

Physalis floridana Cell Number Regulator1 encodes a cell membrane-anchored modulator of cell cycle and negatively controls fruit size

PubMed Central

Li, Zhichao; He, Chaoying

2015-01-01

Physalis species show a significant variation in berry size; however, the underlying molecular basis is unknown. In this work, we showed that cell division difference in the ovaries might contribute to the ultimate berry size variation within Physalis species, and that mRNA abundance of Physalis floridana Cell Number Regulator1 (PfCNR1), the putative orthologue of the tomato fruit weight 2.2 (FW2.2), was negatively correlated with cell division in the ovaries. Moreover, heterochronic expression variation of the PfCNR1 genes in the ovaries concomitantly correlated with berry weight variation within Physalis species. In transgenic Physalis, multiple organ sizes could be negatively controlled by altering PfCNR1 levels, and cell division instead of cell expansion was primarily affected. PfCNR1 was shown to be anchored in the plasma membrane and to interact with PfAG2 (an AGAMOUS-like protein determining ovary identity). The expression of PfCYCD2;1, a putative orthologue of the mitosis-specific gene CyclinD2;1 in the cell cycle was negatively correlated with the PfCNR1 mRNA levels. PfAG2 was found to selectively bind to the CArG-box in the PfCYCD2;1 promoter and to repress PfCYCD2;1 expression, thus suggesting a PfAG2-mediated pathway for PfCNR1 to regulate cell division. The interaction of PfCNR1 with PfAG2 enhanced the repression of PfCYCD2;1 expression. The nuclear import of PfAG2 was essential in the proposed pathway. Our data provide new insights into the developmental pathways of a cell membrane-anchored protein that modulates cell division and governs organ size determination. This study also sheds light on the link between organ identity and organ growth in plants. PMID:25305759

Characterization of memory and measurement history in photoconductivity of nanocrystal arrays

NASA Astrophysics Data System (ADS)

Fairfield, Jessamyn A.; Dadosh, Tali; Drndic, Marija

2010-10-01

Photoconductivity in nanocrystal films has been previously characterized, but memory effects have received little attention despite their importance for device applications. We show that the magnitude and temperature dependence of the photocurrent in CdSe/ZnS core-shell nanocrystal arrays depends on the illumination and electric field history. Changes in photoconductivity occur on a few-hour timescale, and subband gap illumination of nanocrystals prior to measurements modifies the photocurrent more than band gap illumination. The observed effects can be explained by charge traps within the band gap that are filled or emptied, which may alter nonradiative recombination processes and affect photocurrent.

Mediating Pathways in the Socio-Economic Gradient of Child Development: Evidence from Children 6-42 Months in Bogota

ERIC Educational Resources Information Center

Rubio-Codina, Marta; Attanasio, Orazio; Grantham-McGregor, Sally

2016-01-01

Research has previously shown a gap of near 0.5 of a standard deviation (SD) in cognition and language development between the top and bottom household wealth quartile in children aged 6-42 months in a large representative sample of low- and middle-income families in Bogota, using the Bayley Scales of Infant and Toddler Development. The gaps in…

Baking loss of bread with special emphasis on increasing water holding capacity.

PubMed

Kotoki, D; Deka, S C

2010-01-01

Potato flour (PF), hydroxypropyl methylcellulose (HPMC) and honey were used as baking agents and their effects on baking loss and sensory quality were studied. PF at 1, 2 and 4% levels decreased baking loss followed by HPMC and honey. Water absorption was substantially high with the HPMC (70.8-80.8%) and PF (61.7-71.7%) compared to honey and normal standard bread. PF incorporation increased shelf-life (6-7 days) as compared to HPMC and honey. HPMC incorporated bread had higher moisture content (36.8-38.0%) followed by PF (34.5-35.8%) and honey (34.7%). The ash content was in the order of PF (1%) > honey (4%) > PF (2%) > normal bread > HPMC (0.5 g) > PF (4%) > HPMC (1 g) > HPMC (1.5 g). PF incorporated bread had sensorily highest acceptance followed by HPMC and honey.

Unpacking personalized feedback: an exploratory study of the impact of its components and the reactions it elicits among problem drinking men who have sex with men.

PubMed

Kuerbis, Alexis Noel; Schaumberg, Katherine; Davis, Christine M; Hail, Lisa; Morgenstern, Jon

2014-03-01

Personalized feedback (PF) has demonstrated effectiveness in reducing drinking. Few studies have examined its effectiveness with adult problem drinkers or its potential mediators or moderators, including developing discrepancy. This study aimed to identify potential mediators and moderators of PF provided to adult problem drinking men who have sex with men (PDMSM). An exploratory analysis of PF provided to PDMSM in the context of modified behavioral self-control therapy (N = 90). The association of individual items of PF, severity of PF, and independently rated, in-session participant reactions to PF with drinking outcomes (mean drinks per drinking day, MDDD) were examined using correlations and logistic and linear regression. Significant pre-post differences in MDDD emerged. Other drug risk, family risk, and having an abnormal liver enzyme test result were significantly associated with proxies for developed discrepancy in expected directions; however, no PF item or reaction to PF predicted drinking outcomes. Severity of PF was not associated with participant reactions or drinking outcome. PF may be an effective intervention for PDMSM. Further research is needed to identify potential mediators and moderators of PF among adults.

Multiple Drugs Compete for Transport via the Plasmodium falciparum Chloroquine Resistance Transporter at Distinct but Interdependent Sites*

PubMed Central

Bellanca, Sebastiano; Summers, Robert L.; Meyrath, Max; Dave, Anurag; Nash, Megan N.; Dittmer, Martin; Sanchez, Cecilia P.; Stein, Wilfred D.; Martin, Rowena E.; Lanzer, Michael

2014-01-01

Mutations in the “chloroquine resistance transporter” (PfCRT) are a major determinant of drug resistance in the malaria parasite Plasmodium falciparum. We have previously shown that mutant PfCRT transports the antimalarial drug chloroquine away from its target, whereas the wild-type form of PfCRT does not. However, little is understood about the transport of other drugs via PfCRT or the mechanism by which PfCRT recognizes different substrates. Here we show that mutant PfCRT also transports quinine, quinidine, and verapamil, indicating that the protein behaves as a multidrug resistance carrier. Detailed kinetic analyses revealed that chloroquine and quinine compete for transport via PfCRT in a manner that is consistent with mixed-type inhibition. Moreover, our analyses suggest that PfCRT accepts chloroquine and quinine at distinct but antagonistically interacting sites. We also found verapamil to be a partial mixed-type inhibitor of chloroquine transport via PfCRT, further supporting the idea that PfCRT possesses multiple substrate-binding sites. Our findings provide new mechanistic insights into the workings of PfCRT, which could be exploited to design potent inhibitors of this key mediator of drug resistance. PMID:25378409

Mn@Si14+: a singlet fullerene-like endohedrally doped silicon cluster.

PubMed

Ngan, Vu Thi; Pierloot, Kristine; Nguyen, Minh Tho

2013-04-21

The electronic structure of Mn@Si14(+) is determined using DFT and CASPT2/CASSCF(14,15) computations with large basis sets. The endohedrally Mn-doped Si cationic cluster has a D3h fullerene-like structure featuring a closed-shell singlet ground state with a singlet-triplet gap of ~1 eV. A strong stabilizing interaction occurs between the 3d(Mn) and the 2D-shell(Si14) orbitals, and a large amount of charge is transferred from the Si14 cage to the Mn dopant. The 3d(Mn) orbitals are filled by encapsulation, and the magnetic moment of Mn is completely quenched. Full occupation of [2S, 2P, 2D] shell orbitals by 18 delocalized electrons confers the doped Mn@Si14(+) cluster a spherically aromatic character.

Evaluation of a Plasmodium-Specific Carrier Protein To Enhance Production of Recombinant Pfs25, a Leading Transmission-Blocking Vaccine Candidate.

PubMed

Parzych, Elizabeth M; Miura, Kazutoyo; Ramanathan, Aarti; Long, Carole A; Burns, James M

2018-01-01

Challenges with the production and suboptimal immunogenicity of malaria vaccine candidates have slowed the development of a Plasmodium falciparum multiantigen vaccine. Attempting to resolve these issues, we focused on the use of highly immunogenic merozoite surface protein 8 (MSP8) as a vaccine carrier protein. Previously, we showed that a genetic fusion of the C-terminal 19-kDa fragment of merozoite surface protein 1 (MSP1 19 ) to P. falciparum MSP8 ( Pf MSP8) facilitated antigen production and folding and the induction of neutralizing antibodies to conformational B cell epitopes of MSP1 19 Here, using the Pf MSP1/8 construct, we further optimized the recombinant Pf MSP8 (r Pf MSP8) carrier by the introduction of two cysteine-to-serine substitutions (CΔS) to improve the yield of the monomeric product. We then sought to test the broad applicability of this approach using the transmission-blocking vaccine candidate Pf s25. The production of r Pf s25-based vaccines has presented challenges. Antibodies directed against the four highly constrained epidermal growth factor (EGF)-like domains of Pf s25 block sexual-stage development in mosquitoes. The sequence encoding mature Pf s25 was codon harmonized for expression in Escherichia coli We produced a r Pf s25- Pf MSP8 fusion protein [r Pf s25/8(CΔS)] as well as unfused, mature r Pf s25. r Pf s25 was purified with a modest yield but required the incorporation of refolding protocols to obtain a proper conformation. In comparison, chimeric r Pf s25/8(CΔS) was expressed and easily purified, with the Pf s25 domain bearing the proper conformation without renaturation. Both antigens were immunogenic in rabbits, inducing IgG that bound native Pf s25 and exhibited potent transmission-reducing activity. These data further demonstrate the utility of Pf MSP8 as a parasite-specific carrier protein to enhance the production of complex malaria vaccine targets. Copyright © 2017 American Society for Microbiology.

The COOH-terminal peptide of platelet factor-4 variant (CXCL4L1/PF-4var47-70) strongly inhibits angiogenesis and suppresses B16 melanoma growth in vivo.

PubMed

Vandercappellen, Jo; Liekens, Sandra; Bronckaers, Annelies; Noppen, Samuel; Ronsse, Isabelle; Dillen, Chris; Belleri, Mirella; Mitola, Stefania; Proost, Paul; Presta, Marco; Struyf, Sofie; Van Damme, Jo

2010-03-01

Chemokines influence tumor growth directly or indirectly via both angiogenesis and tumor-leukocyte interactions. Platelet factor-4 (CXCL4/PF-4), which is released from alpha-granules of activated platelets, is the first described angiostatic chemokine. Recently, it was found that the variant of CXCL4/PF-4 (CXCL4L1/PF-4var) could exert a more pronounced angiostatic and antitumoral effect than CXCL4/PF-4. However, the molecular mechanisms of the angiostatic activities of the PF-4 forms remain partially elusive. Here, we studied the biological properties of the chemically synthesized COOH-terminal peptides of CXCL4/PF-4 (CXCL4/PF-4(47-70)) and CXCL4L1/PF-4var (CXCL4L1/PF-4var(47-70)). Both PF-4 peptides lacked monocyte and lymphocyte chemotactic activity but equally well inhibited (25 nmol/L) endothelial cell motility and proliferation in the presence of a single stimulus (i.e., exogenous recombinant fibroblast growth factor-2). In contrast, when assayed in more complex angiogenesis test systems characterized by the presence of multiple mediators, including in vitro wound-healing (2.5 nmol/L versus 12.5 nmol/L), Matrigel (60 nmol/L versus 300 nmol/L), and chorioallantoic membrane assays, CXCL4L1/PF-4var(47-70) was found to be significantly (5-fold) more angiostatic than CXCL4/PF-4(47-70). In addition, low (7 microg total) doses of intratumoral CXCL4L1/PF-4var(47-70) inhibited B16 melanoma growth in mice more extensively than CXCL4/PF-4(47-70). This antitumoral activity was predominantly mediated through inhibition of angiogenesis (without affecting blood vessel stability) and induction of apoptosis, as evidenced by immunohistochemical and fluorescent staining of B16 tumor tissue. In conclusion, CXCL4L1/PF-4var(47-70) is a potent antitumoral and antiangiogenic peptide. These results may represent the basis for the design of CXCL4L1/PF-4var COOH-terminal-derived peptidomimetic anticancer drugs.

Enhancement of Thermoelectric Performances in a Topological Crystal Insulator Pb0.7Sn0.3Se via Weak Perturbation of the Topological State and Chemical Potential Tuning by Chlorine Doping.

PubMed

Lin, Chan-Chieh; Kim, Gareoung; Ginting, Dianta; Ahn, Kyunghan; Rhyee, Jong-Soo

2018-04-04

Topological insulators generally share commonalities with good thermoelectric (TE) materials because of their narrow band gaps and heavy constituent elements. Here, we propose that a topological crystalline insulator (TCI) could exhibit a high TE performance by breaking its crystalline symmetry and tuning the chemical potential by elemental doping. As a candidate material, we investigate the TE properties of the Cl-doped TCI Pb 0.7 Sn 0.3 Se. The infrared absorption spectra reveal that the band gap is increased from 0.055 eV for Pb 0.7 Sn 0.3 Se to 0.075 eV for Pb 0.7 Sn 0.3 Se 0.99 Cl 0.01 , confirming that the Cl doping can break the crystalline mirror symmetry of a TCI Pb 0.7 Sn 0.3 Se and thereby enlarge its bulk electronic band gap. The topological band inversion is confirmed by the extended X-ray absorption fine structure spectroscopy, which shows that the TCI state is weakened in a chlorine x = 0.05-doped compound. The small gap opening and partial linear band dispersion with massless and massive bands may have a high power factor (PF) for high electrical conductivity with an enhancement of the Seebeck coefficient. As a result, Pb 0.7 Sn 0.3 Se 0.99 Cl 0.01 shows a considerably enhanced ZT of 0.64 at 823 K, which is about 1200% enhancement in ZT compared with that of the undoped Pb 0.7 Sn 0.3 Se. This work demonstrates that the optimal n-type Cl doping tunes the chemical potential together with breaking the state of the TCI, suppresses the bipolar conduction at high temperatures, and thereby enables the Seebeck coefficient to increase up to 823 K, resulting in a significantly enhanced PF at high temperatures. In addition, the bipolar contribution to thermal conductivity is effectively suppressed for the Cl-doped samples of Pb 0.7 Sn 0.3 Se 1- x Cl x ( x ≥ 0.01). We propose that breaking the crystalline mirror symmetry in TCIs could be a new research direction for exploring high-performance TE materials.

A critical period for functional vestibular development in zebrafish

NASA Technical Reports Server (NTRS)

Moorman, Stephen J.; Cordova, Rodolfo; Davies, Sarah A.

2002-01-01

We have determined a critical period for vestibular development in zebrafish by using a bioreactor designed by NASA to simulate microgravity for cells in culture. A critical period is defined as the briefest period of time during development when stimulus deprivation results in long lasting or permanent sensory deficits. Zebrafish eggs were collected within 3 hours of being laid and fertilized. In experiment 1, eggs were placed in the bioreactor at 3, 24, 30, 36, 48, or 72 hours postfertilization (hPF) and maintained in the bioreactor until 96 hPF. In experiment 2, eggs were placed in the bioreactor immediately after they were collected and maintained in the bioreactor until 24, 36, 48, 60, 66, 72, or 96 hPF. Beginning at 96 hPF, all larvae had their vestibulo-ocular reflexes (VOR) evaluated once each day for 5 days. Only larvae that hatched from eggs that were placed in the bioreactor before 30 hPF in experiment 1 or removed from the bioreactor later than 66 hPF in experiment 2 had VOR deficits that persisted for at least 5 days. These data suggest a critical period for vestibular development in the zebrafish that begins before 30 hPF and ends after 66 hPF. To confirm this, zebrafish eggs were placed in the bioreactor at 24 hPF and removed at 72 hPF. VORs were evaluated in these larvae once each day for 5 days beginning at 96 hPF. These larvae had VOR deficits that persisted for at least 5 days. In addition, larvae that had been maintained in the bioreactor from 24 to 66 hPF or from 30 to 72 hPF, had only temporary VOR deficits. In a final experiment, zebrafish eggs were placed in the bioreactor at 3 hPF and removed at 96 hPF but the bioreactor was turned off from 24 hPF to 72 hPF. These larvae had normal VORs when they were removed from the bioreactor at 96 hPF. Taken as a whole, these data support the idea that there is a critical period for functional maturation of the zebrafish vestibular system. The developmental period identified includes the timeframe during which the vestibular primary afferent neurons are born, innervate their central and peripheral targets, and remodel their central projections. Copyright 2002 Wiley-Liss, Inc.

Effects of peritoneal fluid from endometriosis patients on the release of monocyte-specific chemokines by leukocytes.

PubMed

Na, Yong-Jin; Lee, Dong-Hyung; Kim, Seung-Chul; Joo, Jong-Kil; Wang, Ji-Won; Jin, Jun-O; Kwak, Jong-Young; Lee, Kyu-Sup

2011-06-01

Chemokines have been implicated in the pathological process of endometriosis. We compared the effects of peritoneal fluid obtained from patients with endometriosis (ePF) and controls without endometriosis (cPF) on the release of monocyte-specific CC chemokines such as monocyte chemotactic protein-1 (MCP-1), regulated upon activation normal T cell expressed and secreted (RANTES), and macrophage inflammatory protein-1α (MIP-1α) by neutrophils, monocytes, and T cells. Moreover, we evaluated the correlation between the levels of chemokines in ePF and their release by these cells. Cells were obtained from healthy young volunteers and cultured with ePF (n = 12) or cPF (n = 8). The chemokine levels in the ePF and the supernatants of cultured cells with ePF were then measured by ELISA. There was a positive correlation between the levels of MCP-1 and MIP-1α in ePF. The addition of ePF to the cell cultures failed to increase the release of MCP-1, RANTES, and MIP-1α when compared to cPF, but the levels of RANTES in ePF were positively correlated with the release of RANTES by ePF-treated monocytes and T cells. Moreover, there was a positive correlation between the levels of RANTES and MIP-1α released by neutrophils and between the levels of MCP-1 and MIP-1α released by T cells. Finally, the levels of RANTES released by monocyte-derived macrophages and monocytes cultured with ePF were positively correlated. These findings suggest that monocytes, neutrophils, and T cells release differential levels of MCP-1, RANTES, and MIP-1α in response to stimulation with ePF.

Implications of Parasites Lacking Plasmodium falciparum Histidine-Rich Protein 2 on Malaria Morbidity and Control When Rapid Diagnostic Tests Are Used for Diagnosis.

PubMed

Gatton, Michelle L; Dunn, Jessica; Chaudhry, Alisha; Ciketic, Sadmir; Cunningham, Jane; Cheng, Qin

2017-04-01

Rapid diagnostic tests (RDTs) are an important tool for malaria diagnosis, with most using antibodies against Plasmodium falciparum histidine-rich protein 2 (PfHRP2). Reports of P. falciparum lacking this protein are increasing, creating a problem for diagnosis of falciparum malaria in locations without quality-assured microscopy. An agent-based stochastic simulation model of P. falciparum transmission was used to investigate the selective pressure exerted on parasite populations by use of RDTs for diagnosis of symptomatic cases. The model considered parasites with normal, reduced, or no PfHRP2, and diagnosis using PfHRP2-only or combination RDTs. Use of PfHRP2-only RDTs in communities where a PfHRP2-negative parasite was introduced during the simulation resulted in transmission of the parasite in >80% of cases, compared with <30% for normal or PfHRP2-reduced parasites. Using PfHRP2-only RDTs in the presence of PfHRP2-negative parasites caused an increase in prevalence, reduced RDT positivity within symptomatic patients but no change in the number of antimalarial treatments due to false-negative RDT results. Diagnosis with PfHRP2/Pf-Plasmodium lactate dehydrogenase combination RDTs did not select for PfHRP2-negative parasites. The use of PfHRP2-only RDTs is sufficient to select P. falciparum parasites lacking this protein, thus posing a significant public health problem, which could be moderated by using PfHRP2/Pf-Plasmodium lactate dehydrogenase combination RDTs. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Expansion of a physical function item bank and development of an abbreviated form for clinical research.

PubMed

Bode, Rita K; Lai, Jin-shei; Dineen, Kelly; Heinemann, Allen W; Shevrin, Daniel; Von Roenn, Jamie; Cella, David

2006-01-01

We expanded an existing 33-item physical function (PF) item bank with a sufficient number of items to enable computerized adaptive testing (CAT). Ten items were written to expand the bank and the new item pool was administered to 295 people with cancer. For this analysis of the new pool, seven poorly performing items were identified for further examination. This resulted in a bank with items that define an essentially unidimensional PF construct, cover a wide range of that construct, reliably measure the PF of persons with cancer, and distinguish differences in self-reported functional performance levels. We also developed a 5-item (static) assessment form ("BriefPF") that can be used in clinical research to express scores on the same metric as the overall bank. The BriefPF was compared to the PF-10 from the Medical Outcomes Study SF-36. Both short forms significantly differentiated persons across functional performance levels. While the entire bank was more precise across the PF continuum than either short form, there were differences in the area of the continuum in which each short form was more precise: the BriefPF was more precise than the PF-10 at the lower functional levels and the PF-10 was more precise than the BriefPF at the higher levels. Future research on this bank will include the development of a CAT version, the PF-CAT.

Studies of Copper, Silver, and Gold Cluster Anions: Evidence of Electronic Shell Structure.

NASA Astrophysics Data System (ADS)

Pettiette, Claire Lynn

A new Ultraviolet Magnetic Time-of-Flight Photoelectron Spectrometer (MTOFPES) has been developed for the study of the electronic structure of clusters produced in a pulsed supersonic molecular beam. This is the first technique which has been successful in probing the valence electronic states of metal clusters. The ultraviolet photoelectron spectra of negative cluster ions of the noble metals have been taken at several different photon energies. These are presented along with the electron affinity and HOMO-LUMO gap measurements for Cu_6^- to Cu_ {41}^-, using 4.66 eV and 6.42 eV detachment energies; Ag_3^- to Ag_{21}^-, using 6.42 eV detachment energy; and Au_3^ - to Au_{21}^-, using 6.42 eV and 7.89 eV detachment energies. The spectra provide the first detailed probes of the s valence electrons of the noble metal clusters. In addition, the 6.42 eV and 7.89 eV spectra probe the first one to two electron volts of the molecular orbitals of the d valence electrons of copper and gold clusters. The electron affinity and HOMO-LUMO gap measurements of the noble metal clusters agree with the predictions of the ellipsoidal shell model for mono-valent metal clusters. In particular, cluster numbers 8, 20, and 40--which correspond to the spherical shell closings of this model--have low electron affinities and large HOMO-LUMO gaps. The spectra of the gold cluster ions indicate that the molecular orbital energies of the cluster valence electrons are more widely spaced for gold than for copper or silver. This is to be expected for the heavy atom clusters when relativistic effects are taken into account.

Pf155/RESA protein influences the dynamic microcirculatory behavior of ring-stage Plasmodium falciparum infected red blood cells

PubMed Central

Diez-Silva, Monica; Park, YongKeun; Huang, Sha; Bow, Hansen; Mercereau-Puijalon, Odile; Deplaine, Guillaume; Lavazec, Catherine; Perrot, Sylvie; Bonnefoy, Serge; Feld, Michael S.; Han, Jongyoon; Dao, Ming; Suresh, Subra

2012-01-01

Proteins exported by Plasmodium falciparum to the red blood cell (RBC) membrane modify the structural properties of the parasitized RBC (Pf-RBC). Although quasi-static single cell assays show reduced ring-stage Pf-RBCs deformability, the parameters influencing their microcirculatory behavior remain unexplored. Here, we study the dynamic properties of ring-stage Pf-RBCs and the role of the parasite protein Pf155/Ring-Infected Erythrocyte Surface Antigen (RESA). Diffraction phase microscopy revealed RESA-driven decreased Pf-RBCs membrane fluctuations. Microfluidic experiments showed a RESA-dependent reduction in the Pf-RBCs transit velocity, which was potentiated at febrile temperature. In a microspheres filtration system, incubation at febrile temperature impaired traversal of RESA-expressing Pf-RBCs. These results show that RESA influences ring-stage Pf-RBCs microcirculation, an effect that is fever-enhanced. This is the first identification of a parasite factor influencing the dynamic circulation of young asexual Pf-RBCs in physiologically relevant conditions, offering novel possibilities for interventions to reduce parasite survival and pathogenesis in its human host. PMID:22937223

Pf155/RESA protein influences the dynamic microcirculatory behavior of ring-stage Plasmodium falciparum infected red blood cells

NASA Astrophysics Data System (ADS)

Diez-Silva, Monica; Park, Yongkeun; Huang, Sha; Bow, Hansen; Mercereau-Puijalon, Odile; Deplaine, Guillaume; Lavazec, Catherine; Perrot, Sylvie; Bonnefoy, Serge; Feld, Michael S.; Han, Jongyoon; Dao, Ming; Suresh, Subra

2012-08-01

Proteins exported by Plasmodium falciparum to the red blood cell (RBC) membrane modify the structural properties of the parasitized RBC (Pf-RBC). Although quasi-static single cell assays show reduced ring-stage Pf-RBCs deformability, the parameters influencing their microcirculatory behavior remain unexplored. Here, we study the dynamic properties of ring-stage Pf-RBCs and the role of the parasite protein Pf155/Ring-Infected Erythrocyte Surface Antigen (RESA). Diffraction phase microscopy revealed RESA-driven decreased Pf-RBCs membrane fluctuations. Microfluidic experiments showed a RESA-dependent reduction in the Pf-RBCs transit velocity, which was potentiated at febrile temperature. In a microspheres filtration system, incubation at febrile temperature impaired traversal of RESA-expressing Pf-RBCs. These results show that RESA influences ring-stage Pf-RBCs microcirculation, an effect that is fever-enhanced. This is the first identification of a parasite factor influencing the dynamic circulation of young asexual Pf-RBCs in physiologically relevant conditions, offering novel possibilities for interventions to reduce parasite survival and pathogenesis in its human host.

The role of the CXC chemokines platelet factor-4 (CXCL4/PF-4) and its variant (CXCL4L1/PF-4var) in inflammation, angiogenesis and cancer.

PubMed

Vandercappellen, Jo; Van Damme, Jo; Struyf, Sofie

2011-02-01

Chemokines are chemotactic cytokines which recruit leukocytes to inflammatory sites. They also affect tumor development and metastasis by acting as growth factor, by attracting pro- or anti-tumoral leukocytes or by influencing angiogenesis. Platelet factor-4 (CXCL4/PF-4) was the first chemokine shown to inhibit angiogenesis. CXCL4L1/PF-4var, recently isolated from thrombin-stimulated platelets, differing from authentic CXCL4/PF-4 in three carboxy-terminally located amino acids, was found to be more potent than CXCL4/PF-4 in inhibiting angiogenesis and tumor growth. Both glycosaminoglycans (GAG) and CXCR3 are implicated in the activities of the PF-4 variants. This report reviews the current knowledge on the role of CXCL4/PF-4 and CXCL4L1/PF-4var in physiological and pathological processes. In particular, the role of CXCL4/PF-4 in cancer, heparin-induced thrombocytopenia and atherosclerosis is described. Copyright © 2010 Elsevier Ltd. All rights reserved.

Controlled Human Malaria Infection of Tanzanians by Intradermal Injection of Aseptic, Purified, Cryopreserved Plasmodium falciparum Sporozoites

PubMed Central

Shekalaghe, Seif; Rutaihwa, Mastidia; Billingsley, Peter F.; Chemba, Mwajuma; Daubenberger, Claudia A.; James, Eric R.; Mpina, Maximillian; Ali Juma, Omar; Schindler, Tobias; Huber, Eric; Gunasekera, Anusha; Manoj, Anita; Simon, Beatus; Saverino, Elizabeth; Church, L. W. Preston; Hermsen, Cornelus C.; Sauerwein, Robert W.; Plowe, Christopher; Venkatesan, Meera; Sasi, Philip; Lweno, Omar; Mutani, Paul; Hamad, Ali; Mohammed, Ali; Urassa, Alwisa; Mzee, Tutu; Padilla, Debbie; Ruben, Adam; Lee Sim, B. Kim; Tanner, Marcel; Abdulla, Salim; Hoffman, Stephen L.

2014-01-01

Controlled human malaria infection (CHMI) by mosquito bite has been used to assess anti-malaria interventions in > 1,500 volunteers since development of methods for infecting mosquitoes by feeding on Plasmodium falciparum (Pf) gametocyte cultures. Such CHMIs have never been used in Africa. Aseptic, purified, cryopreserved Pf sporozoites, PfSPZ Challenge, were used to infect Dutch volunteers by intradermal injection. We conducted a double-blind, placebo-controlled trial to assess safety and infectivity of PfSPZ Challenge in adult male Tanzanians. Volunteers were injected intradermally with 10,000 (N = 12) or 25,000 (N = 12) PfSPZ or normal saline (N = 6). PfSPZ Challenge was well tolerated and safe. Eleven of 12 and 10 of 11 subjects, who received 10,000 and 25,000 PfSPZ respectively, developed parasitemia. In 10,000 versus 25,000 PfSPZ groups geometric mean days from injection to Pf positivity by thick blood film was 15.4 versus 13.5 (P = 0.023). Alpha-thalassemia heterozygosity had no apparent effect on infectivity. PfSPZ Challenge was safe, well tolerated, and infectious. PMID:25070995

Anti-Plasmodium falciparum invasion ligand antibodies in a low malaria transmission region, Loreto, Peru

PubMed Central

2012-01-01

Background Erythrocyte invasion by Plasmodium falciparum is a complex process that involves two families; Erythrocyte Binding-Like (EBL) and the Reticulocyte Binding-Like (PfRh) proteins. Antibodies that inhibit merozoite attachment and invasion are believed to be important in mediating naturally acquired immunity and immunity generated by parasite blood stage vaccine candidates. The hypotheses tested in this study were 1) that antibody responses against specific P. falciparum invasion ligands (EBL and PfRh) differ between symptomatic and asymptomatic individuals living in the low-transmission region of the Peruvian Amazon and 2), such antibody responses might have an association, either direct or indirect, with clinical immunity observed in asymptomatically parasitaemic individuals. Methods ELISA was used to assess antibody responses (IgG, IgG1 and IgG3) against recombinant P. falciparum invasion ligands of the EBL (EBA-175, EBA-181, EBA-140) and PfRh families (PfRh1, PfRh2a, PfRh2b, PfRh4 and PfRh5) in 45 individuals infected with P. falciparum from Peruvian Amazon. Individuals were classified as having symptomatic malaria (N=37) or asymptomatic infection (N=8). Results Antibody responses against both EBL and PfRh family proteins were significantly higher in asymptomatic compared to symptomatic individuals, demonstrating an association with clinical immunity. Significant differences in the total IgG responses were observed with EBA-175, EBA-181, PfRh2b, and MSP119 (as a control). IgG1 responses against EBA-181, PfRh2a and PfRh2b were significantly higher in the asymptomatic individuals. Total IgG antibody responses against PfRh1, PfRh2a, PfRh2b, PfRh5, EBA-175, EBA-181 and MSP119 proteins were negatively correlated with level of parasitaemia. IgG1 responses against EBA-181, PfRh2a and PfRh2b and IgG3 response for PfRh2a were also negatively correlated with parasitaemia. Conclusions These data suggest that falciparum malaria patients who develop clinical immunity (asymptomatic parasitaemia) in a low transmission setting such as the Peruvian Amazon have antibody responses to defined P. falciparum invasion ligand proteins higher than those found in symptomatic (non-immune) patients. While these findings will have to be confirmed by larger studies, these results are consistent with a potential role for one or more of these invasion ligands as a component of an anti-P. falciparum vaccine in low-transmission malaria-endemic regions. PMID:23110555

Mobility histories of 7th-9th century AD people buried at early medieval Bamburgh, Northumberland, England.

PubMed

Groves, S E; Roberts, C A; Lucy, S; Pearson, G; Gröcke, D R; Nowell, G; Macpherson, C G; Young, G

2013-07-01

Early Medieval England is described historically as a time when people migrated from the Continent to English shores. This study tests the hypothesis that those buried in the Bowl Hole cemetery, Bamburgh, Northumberland were nonlocally born, because of its royal status. Ninety-one male and female adult, and nonadult, skeletons were studied. Isotope ratios of strontium ((87) Sr/(86) Sr) and oxygen (δ(18) O) were generated for 78 individuals (28 females, 27 males, five "adults," 18 nonadults). The mean Sr value for human enamel was 0.71044, standard deviation (sd) 0.001, and the mean O (δw) value is -5.9‰, sd 1.6‰. Additionally, animal tooth enamel (mean Sr value 0.710587, sd 0.001; mean O value -6.5‰, sd 1.5‰), local soil (mean Sr value 0.709184, sd 0.0006), snail shells (mean Sr value 0.708888, sd 0.0001), and soil samples from a 5 km transect heading inland (mean Sr value 0.709121, sd 0.0003), were analyzed for an indication of the isotopic composition of bioavailable Sr in the modern environment and to assess the impact of sea-spray; water samples from a well, local rivers, and standing water were analyzed for local δ(18) O values (mean O value -6.4‰, relative to VSMOW, sd 2.8‰). Over 50% of those buried at Bamburgh were nonlocal. All ages and both sexes produced "nonlocal" signatures; some suggested childhood origins in Scandinavia, the southern Mediterranean or North Africa. Stature and other indicators of health status indicated differences in quality of life between local and migrant groups. These differences did not extend to burial practices. Copyright © 2013 Wiley Periodicals, Inc.

Development of fisetin-loaded folate functionalized pluronic micelles for breast cancer targeting.

PubMed

Pawar, Atmaram; Singh, Srishti; Rajalakshmi, S; Shaikh, Karimunnisa; Bothiraja, C

2018-01-15

The natural flavonoid fisetin (FS) has shown anticancer properties but its in-vivo administration remains challenging due to its poor aqueous solubility. The aim of the study was to develop FS loaded pluronic127 (PF)-folic acid (FA) conjugated micelles (FS-PF-FA) by the way of increasing solubility, bioavailability and active targetability of FS shall increase its therapeutic efficacy. FA-conjugated PF was prepared by carbodiimide crosslinker chemistry. FS-PF-FA micelles were prepared by thin-film hydration method and evaluated in comparison with free FS and FS loaded PF micelles (FS-PF). The smooth surfaces with spherical in shape of FS-PF-PF micelles displayed smaller in size (103.2 ± 6.1 nm), good encapsulation efficiency (82.50 ± 1.78%), zeta potential (-26.7 ± 0.44 mV) and sustained FS release. Bioavailability of FS from FS-PF-PF micelles was increased by 6-fold with long circulation time, slower plasma elimination and no sign of tissue toxicity as compared to free FS. Further, the FS-PF-FA micelles demonstrated active targeting effect on folate overexpressed human breast cancer MCF-7 cells. The concentration of the drug needed for growth inhibition of 50% of cells in a designed time period (GI50) was 14.3 ± 1.2 µg/ml for FS while it was greatly decreased to 9.8 ± 0.78 µg/ml, i.e. a 31.46% decrease for the FS-PF. Furthermore, the GI50 value for FS-PF-FA was 4.9 ± 0.4 µg/ml, i.e. a 65.737% decrease compared to FS and 50% decrease compare to FS-PF. The results indicate that the FS-PF-FA micelles have the potential to be applied for targeting anticancer drug delivery.

Targeting colorectal cancer cells by a novel sphingosine kinase 1 inhibitor PF-543

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

Ju, TongFa; Gao, DaQuan; Fang, Zheng-yu, E-mail: fangzhengyu158@sina.com

In this study, we showed that PF-543, a novel sphingosine kinase 1 (SphK1) inhibitor, exerted potent anti-proliferative and cytotoxic effects against a panel of established (HCT-116, HT-29 and DLD-1) and primary human colorectal cancer (CRC) cells. Its sensitivity was negatively associated with SphK1 expression level in the CRC cells. Surprisingly, PF-543 mainly induced programmed necrosis, but not apoptosis, in the CRC cells. CRC cell necrotic death was detected by lactate dehydrogenase (LDH) release, mitochondrial membrane potential (MMP) collapse and mitochondrial P53-cyclophilin-D (Cyp-D) complexation. Correspondingly, the necrosis inhibitor necrostatin-1 largely attenuated PF-543-induced cytotoxicity against CRC cells. Meanwhile, the Cyp-D inhibitors (sanglifehrinmore » A and cyclosporin A), or shRNA-mediated knockdown of Cyp-D, remarkably alleviated PF-543-induced CRC cell necrotic death. Reversely, over-expression of wild-type Cyp-D in HCT-116 cells significantly increased PF-543's sensitivity. In vivo, PF-543 intravenous injection significantly suppressed HCT-116 xenograft growth in severe combined immunodeficient (SCID) mice, whiling remarkably improving the mice survival. The in vivo activity by PF-543 was largely attenuated when combined with the Cyp-D inhibitor cyclosporin A. Collectively, our results demonstrate that PF-543 exerts potent anti-CRC activity in vitro and in vivo. Mitochondrial programmed necrosis pathway is likely the key mechanism responsible for PF-543's actions in CRC cells. - Highlights: • PF-543 is anti-proliferative and cytotoxic to established and primary CRC cells. • PF-543 induces programmed necrosis, but not apoptosis, in CRC cells. • Modulation of mitochondrial protein cyclophilin-D alters PF-543's sensitivity. • PF-543 inhibits HCT-116 xenograft growth in SCID mice, improving mice survival. • Co-administration of cyclophilin-D inhibitor CsA inhibits PF-543's activity in vivo.« less

Pelvis width associated with bone mass distribution at the proximal femur in children 10–11 years old

PubMed Central

Cardadeiro, Graça; Baptista, Fátima; Janz, Kathleen F.; Rodrigues, Luís A.; Sardinha, Luís B.

2015-01-01

Differences in skeletal geometry may generate different patterns of mechanical loading to bone. Impact and muscle loading during physical activity have been shown to influence skeletal geometry. The purpose of this study was to compare geometric measures of the pelvis and proximal femur (PF) of young children and to analyze the contribution and potential interaction of these geometric measures with physical activity on PF bone mass distribution. Participants were 149 girls and 145 boys, aged 10–11 years. Total body and left hip DXA scans were used to derive pelvic and PF geometric measures and PF bone mineral density (BMD) at the femoral neck (FN), trochanter (TR), and intertrochanter (IT). These subregions were used to represent bone mass distribution via three BMD ratios: FN:PF, TR:PF, and IT:PF. Physical activity was objectively measured using accelerometry, and maturity was estimated as the years of distance from peak height velocity. When compared to boys, girls had a wider pelvic diameter and greater interacetabular distances (p < 0.001), lower BMD at FN, TR, and IT (p < 0.05), and higher TR:PF (p < 0.001). After controlling for maturity, body height, and lean body mass, the interacetabular distance in girls explained 21.1 % (β = 0.713, p < 0.001) in TR:PF and 2.9 % (β = −0.179, p = 0.031) in the IT:PF. Neck–shaft angle explained 5.6 % (β = −0.265, p = 0.001) of the IT:PF and 3.1 % (β = 0.194, p = 0.018) of the FN:PF. In boys, FN axis length explained 2.9 % (β = 0.195, p = 0.040) of TR:PF. There was no main effect of physical activity or interaction effect with pelvic geometry in explaining BMD differences among the subregions of the PF. Even before sexual dimorphism, girls have a wider pelvis than boys, which accounted for proportionally greater BMD of the TR than other subregions of the PF. PMID:23744478

Glycerol capped PbS/CdS core/shell nanoparticles at different molar ratio and its application in biosensors: An optical properties study

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

Das, D., E-mail: ddasphy014@gmail.com; Hussain, A. M. P.

2016-05-06

Glycerol capped PbS/CdS core/shell type nanoparticles fabricated with two different molar ratios are characterized for study of structural and optical properties. The X-ray diffraction (XRD) pattern exhibits cubic phased polycrystalline nanocrystals. The calculated grain sizes from Williamson-Hall plot were found to be around 6 nm with increased strain. HRTEM investigation confirms the formation of core/shell nanostructures and the sizes of the particles were found to be around 7 nm which is in good agreement with the results of the W-H plot. An increase of band gap with the decrease in precursor concentration is confirmed from the blue shift in the absorption spectramore » and also from Tauc plot. A clear blue shifted intense emission is observed in the photoluminescence spectra with decrease in particle size. Intense luminescence from the core/shell nanostructure may be applied in bio labelling and biosensors.« less

Effect of the shell material and confinement type on the conversion efficiency of core/shell quantum dot nanocrystal solar cells

NASA Astrophysics Data System (ADS)

Sahin, Mehmet

2018-05-01

In this study, the effects of the shell material and confinement type on the conversion efficiency of core/shell quantum dot nanocrystal (QDNC) solar cells have been investigated in detail. For this purpose, the conventional, i.e. original, detailed balance model, developed by Shockley and Queisser to calculate an upper limit for the conversion efficiency of silicon p–n junction solar cells, is modified in a simple and effective way to calculate the conversion efficiency of core/shell QDNC solar cells. Since the existing model relies on the gap energy () of the solar cell, it does not make an estimation about the effect of QDNC materials on the efficiency of the solar cells, and gives the same efficiency values for several QDNC solar cells with the same . The proposed modification, however, estimates a conversion efficiency in relation to the material properties and also the confinement type of the QDNCs. The results of the modified model show that, in contrast to the original one, the conversion efficiencies of different QDNC solar cells, even if they have the same , become different depending upon the confinement type and shell material of the core/shell QDNCs, and this is crucial in the design and fabrication of the new generation solar cells to predict the confinement type and also appropriate QDNC materials for better efficiency.

Majorana states in prismatic core-shell nanowires

NASA Astrophysics Data System (ADS)

Manolescu, Andrei; Sitek, Anna; Osca, Javier; Serra, Llorenç; Gudmundsson, Vidar; Stanescu, Tudor Dan

2017-09-01

We consider core-shell nanowires with conductive shell and insulating core and with polygonal cross section. We investigate the implications of this geometry on Majorana states expected in the presence of proximity-induced superconductivity and an external magnetic field. A typical prismatic nanowire has a hexagonal profile, but square and triangular shapes can also be obtained. The low-energy states are localized at the corners of the cross section, i.e., along the prism edges, and are separated by a gap from higher energy states localized on the sides. The corner localization depends on the details of the shell geometry, i.e., thickness, diameter, and sharpness of the corners. We study systematically the low-energy spectrum of prismatic shells using numerical methods and derive the topological phase diagram as a function of magnetic field and chemical potential for triangular, square, and hexagonal geometries. A strong corner localization enhances the stability of Majorana modes to various perturbations, including the orbital effect of the magnetic field, whereas a weaker localization favorizes orbital effects and reduces the critical magnetic field. The prismatic geometry allows the Majorana zero-energy modes to be accompanied by low-energy states, which we call pseudo Majorana, and which converge to real Majoranas in the limit of small shell thickness. We include the Rashba spin-orbit coupling in a phenomenological manner, assuming a radial electric field across the shell.

Clinical characteristics of fulminant type 1 diabetes associated with pregnancy in China.

PubMed

Liu, Lan; Mao, Jiping; Lu, Zeyuan; Yan, Xiaojie; Bai, Xiaosu; Ye, Yiyi; Zou, Gang

2011-12-01

To report 12 cases of pregnancy-associated fulminant type 1 diabetes mellitus (PF) found in China from 2003 to 2010. The clinical and biochemical characteristics of these cases with PF were compared with a group of cases of child-bearing age with fulminant type 1 diabetes that was not associated with pregnancy (NPF). The clinical and biochemical characteristics of 12 PF cases were analyzed retrospectively and then compared with those characteristics of 20 NPF cases in China. The difference between Chinese and Japanese PF cases was investigated. The mean values of the characteristics from PF and NPF cases in China, including postprandial serum C-peptide concentration, plasma glucose concentration, and serum chloride were different. Compared to the 22 PF cases in Japan, the mean age of these 12 PF cases was much younger. The mean fasting and postprandial serum C-peptide concentration level were lower, and the mean HbA1c levels was higher in 12 PF cases in China. Eight of 12 PF cases in China developed the disease during pregnancy. Other four PF case developed the disease within 2 weeks after delivery. 12 PF cases in China showed more severe beta-cell destruction, the prognosis of their fetuses was extremely poor.

Differential response of oyster shell powder on enzyme profile and nutritional value of oyster mushroom Pleurotus florida PF05.

PubMed

Naraian, Ram; Narayan, Om Prakash; Srivastava, Jatin

2014-01-01

Oyster mushroom Pleurotus florida was cultivated on different combinations of wheat straw (WS) as basal substrate and oyster shell powder (OSP) supplement. The OSP supplementation considerably responded to different cultivation phases. The mycelium grew fast and showed rapid growth rate (8.91 mmd(-1)) in WS + OSP (97 + 3) combination while WS + OSP (92 + 8) showed maximum laccase (3.133 U/g) and Mn peroxidase (MnP) activities (0.091 U/g). The climax level of laccase (5.433 U/g) and MnP (0.097 U/g) was recorded during fruit body initiation in WS + OSP (97 + 3) and WS + OSP (98 + 2) combinations, respectively. The WS + OSP (97 + 3) combination represented the best condition for mushroom cultivation and produced the highest biological efficiency (147%). In addition, protein and lipid contents in fruit bodies were slightly improved in response to OSP. The carbohydrate was significantly increased by raising concentration of OSP. The highest values of protein, carbohydrate, and lipid noted were 31.3 μg/g, 0.0639 (g/g), and 0.373 (g/g) correspondingly. Conclusively it was evident that lower concentrations of OSP acted positively and relatively to higher concentrations and improved nutritional content which may suitably be used to enhance both yield and nutritional values of mushroom.

Experimental Guidance of ISB Corrections via Direct Nuclear Reactions

NASA Astrophysics Data System (ADS)

Leach, K. G.; Garrett, P. E.; Ball, G. C.; Bangay, J. C.; Bianco, L.; Demand, G. A.; Faestermann, T.; Finlay, P.; Green, K. L.; Hertenberger, R.; Kriicken, R.; Phillips, A. A.; Rand, E. T.; Sumithrarachchi, C. S.; Svensson, C. E.; Towner, I. S.; Triambak, S.; Wirth, H.-F.; Wong, J.

2011-09-01

The most recent isospin-symmetry-breaking corrections, δc, of Towner and Hardy for superallowed Fermi β-decay transitions, have included the opening of specific core orbitals. This change has resulted in significant deviations in some of the δc factors from their previous calculations, and an improved agreement of the individual corrected Script Ft values with the overall world average of the 13 most precise cases. While this is consistent with the conserved-vector-current (CVC) hypothesis of the Standard Model, these new calculations must be thoroughly tested, and guidance must be given for the improvement of calculations for the upper-pf shell nuclei. Using the (d,t) reaction mechanism to probe the single neutron wavefunction overlap, information regarding the relevant shell-model configurations needed in the calculation can be determined. An experiment was therefore performed with a 22 MeV polarized deuterium beam from the MP tandem Van de Graaff accelerator in Munich, Germany. Using the Q3D magnetic spectrograph, and a cathode-strip focal-plane detector, outgoing tritons were analyzed at 9 angles between 10° and 60°, up to an excitation energy of 4.8 MeV. This proceeding reports the motivational and experimental details for the 64Zn(d,t)63Zn transfer work presented.

Open-shell characters and second hyperpolarizabilities of one-dimensional graphene nanoflakes composed of trigonal graphene units.

PubMed

Yoneda, Kyohei; Nakano, Masayoshi; Fukui, Hitoshi; Minami, Takuya; Shigeta, Yasuteru; Kubo, Takashi; Botek, Edith; Champagne, Benoît

2011-06-20

The impact of topology on the open-shell characters and the second hyperpolarizabilities (γ) has been addressed for one-dimensional graphene nanoflakes (GNFs) composed of the smallest trigonal graphene (phenalenyl) units. The main results are: 1) These GNFs show not only diradical but also multiradical characters when increasing the number of linked units. 2) GNFs composed of an equivalent number of units can exhibit a wide range of open-shell characters-from nearly closed-shell to pure multiradical characters-depending on the linking pattern of the trigonal units. 3) This wide variation in open-shell characters is explained by their resonance structures and/or by their (HOMO-i)-(LUMO+i) gaps deduced from the orbital correlations. 4) The change in the linking structure of the units can effectively control their open-shell characters as well as their γ values, of which the longitudinal components are significantly enhanced for the singlet GNFs having intermediate open-shell characters. 5) Singlet alternately linked (AL) systems present intermediate multiradical characters even in the case of a large number of units, which creates a significant enhancement of γ with increasing the size, whereas nonalternately linked (NAL) systems, which present pure multiradical characters, possess much smaller γ values. Finally 6) by switching from the singlet to the highest spin states, the γ values of NAL systems hardly change, whereas those of AL systems exhibit large reductions. These fascinating structure-property relationships between the topology of the GNFs, their open-shell characters, and their γ values not only deepen the understanding of open-shell characters of GNFs but aim also at stimulating further design studies to achieve giant NLO responses based on open-shell graphene-like materials. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

From tunable core-shell nanoparticles to plasmonic drawbridges: Active control of nanoparticle optical properties

PubMed Central

Byers, Chad P.; Zhang, Hui; Swearer, Dayne F.; Yorulmaz, Mustafa; Hoener, Benjamin S.; Huang, Da; Hoggard, Anneli; Chang, Wei-Shun; Mulvaney, Paul; Ringe, Emilie; Halas, Naomi J.; Nordlander, Peter; Link, Stephan; Landes, Christy F.

2015-01-01

The optical properties of metallic nanoparticles are highly sensitive to interparticle distance, giving rise to dramatic but frequently irreversible color changes. By electrochemical modification of individual nanoparticles and nanoparticle pairs, we induced equally dramatic, yet reversible, changes in their optical properties. We achieved plasmon tuning by oxidation-reduction chemistry of Ag-AgCl shells on the surfaces of both individual and strongly coupled Au nanoparticle pairs, resulting in extreme but reversible changes in scattering line shape. We demonstrated reversible formation of the charge transfer plasmon mode by switching between capacitive and conductive electronic coupling mechanisms. Dynamic single-particle spectroelectrochemistry also gave an insight into the reaction kinetics and evolution of the charge transfer plasmon mode in an electrochemically tunable structure. Our study represents a highly useful approach to the precise tuning of the morphology of narrow interparticle gaps and will be of value for controlling and activating a range of properties such as extreme plasmon modulation, nanoscopic plasmon switching, and subnanometer tunable gap applications. PMID:26665175

Atomic description of the immune complex involved in heparin-induced thrombocytopenia

DOE PAGES

Cai, Zheng; Yarovoi, Serge V.; Zhu, Zhiqiang; ...

2015-09-22

Heparin-induced thrombocytopenia (HIT) is an autoimmune thrombotic disorder caused by immune complexes containing platelet factor 4 (PF4), antibodies to PF4 and heparin or cellular glycosaminoglycans (GAGs). Here we solve the crystal structures of the: (1) PF4 tetramer/fondaparinux complex, (2) PF4 tetramer/KKO-Fab complex (a murine monoclonal HIT-like antibody) and (3) PF4 monomer/RTO-Fab complex (a non-HIT anti-PF4 monoclonal antibody). Fondaparinux binds to the ‘closed’ end of the PF4 tetramer and stabilizes its conformation. This interaction in turn stabilizes the epitope for KKO on the ‘open’ end of the tetramer. Fondaparinux and KKO thereby collaborate to ‘stabilize’ the ternary pathogenic immune complex. Bindingmore » of RTO to PF4 monomers prevents PF4 tetramerization and inhibits KKO and human HIT IgG-induced platelet activation and platelet aggregation in vitro, and thrombus progression in vivo. Lastly, the atomic structures provide a basis to develop new diagnostics and non-anticoagulant therapeutics for HIT.« less

Solvate Structures and Computational/Spectroscopic Characterization of LiPF6 Electrolytes

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

Han, Sang D.; Yun, Sung-Hyun; Borodin, Oleg

2015-04-23

Raman spectroscopy is a powerful method for identifying ion-ion interactions, but only if the vibrational band signature for the anion coordination modes can be accurately deciphered. The present study characterizes the PF6- anion P-F Raman symmetric stretching vibrational band for evaluating the PF6-...Li+ cation interactions within LiPF6 crystalline solvates to create a characterization tool for liquid electrolytes. To facilitate this, the crystal structures for two new solvates—(G3)1:LiPF6 and (DEC)2:LiPF6 with triglyme and diethyl carbonate, respectively—are reported. The information obtained from this analysis provides key guidance about the ionic association information which may be obtained from a Raman spectroscopic evaluation ofmore » electrolytes containing the LiPF6 salt and aprotic solvents. Of particular note is the overlap of the Raman bands for both solvent-separated ion pair (SSIP) and contact ion pair (CIP) coordination in which the PF6- anions are uncoordinated or coordinated to a single Li+ cation, respectively.« less

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

Cai, Zheng; Yarovoi, Serge V.; Zhu, Zhiqiang

Heparin-induced thrombocytopenia (HIT) is an autoimmune thrombotic disorder caused by immune complexes containing platelet factor 4 (PF4), antibodies to PF4 and heparin or cellular glycosaminoglycans (GAGs). Here we solve the crystal structures of the: (1) PF4 tetramer/fondaparinux complex, (2) PF4 tetramer/KKO-Fab complex (a murine monoclonal HIT-like antibody) and (3) PF4 monomer/RTO-Fab complex (a non-HIT anti-PF4 monoclonal antibody). Fondaparinux binds to the ‘closed’ end of the PF4 tetramer and stabilizes its conformation. This interaction in turn stabilizes the epitope for KKO on the ‘open’ end of the tetramer. Fondaparinux and KKO thereby collaborate to ‘stabilize’ the ternary pathogenic immune complex. Bindingmore » of RTO to PF4 monomers prevents PF4 tetramerization and inhibits KKO and human HIT IgG-induced platelet activation and platelet aggregation in vitro, and thrombus progression in vivo. Lastly, the atomic structures provide a basis to develop new diagnostics and non-anticoagulant therapeutics for HIT.« less

Kinematic arguments against single relativistic shell models for GRBs

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

Fenimore, E.E.; Ramirez, E.; Sumner, M.C.

1997-09-01

Two main types of models have been suggested to explain the long durations and multiple peaks of Gamma Ray Bursts (GRBs). In one, there is a very quick release of energy at a central site resulting in a single relativistic shell that produces peaks in the time history through its interactions with the ambient material. In the other, the central site sporadically releases energy over hundreds of seconds forming a peak with each burst of energy. The authors show that the average envelope of emission and the presence of gaps in GRBs are inconsistent with a single relativistic shell. Theymore » estimate that the maximum fraction of a single shell that can produce gamma-rays in a GRB with multiple peaks is 10{sup {minus}3}, implying that single relativistic shells require 10{sup 3} times more energy than previously thought. They conclude that either the central site of a GRB must produce {approx}10{sup 51} erg/s{sup {minus}1} for hundreds of seconds, or the relativistic shell must have structure on a scales the order of {radical}{epsilon}{Gamma}{sup {minus}1}, where {Gamma} is the bulk Lorentz factor ({approximately}10{sup 2} to 10{sup 3}) and {epsilon} is the efficiency.« less

The timing of cortical granule fusion, content dispersal, and endocytosis during fertilization of the hamster egg: an electrophysiological and histochemical study.

PubMed

Kline, D; Stewart-Savage, J

1994-03-01

To determine the temporal relationship between cortical granule exocytosis and the repetitive calcium transients, which are characteristic of mammalian fertilization, we monitored membrane addition from exocytosis during fertilization of hamster eggs. Continuous measurement of membrane capacitance by applying a 3.1-nA alternating current at 375 Hz showed addition of cortical granule membrane. Simultaneous measurement of membrane potential revealed each calcium transient by the appearance of transient hyperpolarizing responses due to calcium-activated potassium channels in the egg. The initial membrane capacitance of the eggs averaged 736 +/- 44 pF (mean +/- SD; n = 7) and an increase in capacitance of 61 +/- 19 pF occurred within 4 sec of the start of the first hyperpolarizing response (HR) after fertilization. Immediately after the first increase in capacitance there was a gradual decline in membrane capacitance in all eggs and in five/seven eggs the capacitance returned to the unfertilized level in 7.8 +/- 4.4 min. The gradual decline in capacitance after the first increase indicated endocytosis, which was confirmed by the internalization of fluorescently labeled dextran. Superimposed on the gradual decline in membrane capacitance were smaller increases in capacitance that occurred with the second and later HRs. The total increase in capacitance from the first three events averaged 72 +/- 19 pF, representing an average increase in capacitance of about 10% of the capacitance of the unfertilized egg. By labeling eggs before and after permeabilization with two different fluorochromes attached to Lens culinaris agglutinin, we demonstrate that the dispersal of the cortical granules contents does not occur immediately after exocytosis. Our results demonstrate that cortical granule exocytosis in hamster eggs is closely coupled to the periodic increases in calcium, that the contents of the cortical granules are slow to disperse, and that after exocytosis, the surface area of the egg returns to the unfertilized level because of a period of endocytosis.

SU-E-T-483: In Vivo Dosimetry of Conventional and Rotational Intensity Modulated Radiotherapy Using Integral Quality Monitor (IQM)

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

Lin, L; Qian, J; Gonzales, R

Purpose: To investigate the accuracy, sensitivity and constancy of integral quality monitor (IQM), a new system for in vivo dosimetry of conventional intensity modulated radiation therapy (IMRT) or rotational volumetric modulated arc therapy (VMAT) Methods: A beta-version IQM system was commissioned on an Elekta Infinity LINAC equipped with 160-MLCs Agility head. The stationary and rotational dosimetric constancy of IQM was evaluated, using five-field IMRT and single-or double-arc VMAT plans for prostate and head-and-neck (H&N) patients. The plans were delivered three times over three days to assess the constancy of IQM response. Picket fence (PF) fields were used to evaluate themore » sensitivity of detecting MLC leaf errors. A single leaf offset was intentionally introduced during delivery of various PF fields with segment apertures of 3×1, 5×1, 10×1, and 24×1cm2. Both 2mm and 5mm decrease in the field width were used. Results: Repeated IQM measurements of prostate and H&N IMRT deliveries showed 0.4 and 0.5% average standard deviation (SD) for segment-by-segment comparison and 0.1 and 0.2% for cumulative comparison. The corresponding SDs for VMAT deliveries were 6.5, 9.4% and 0.7, 1.3%, respectively. Statistical analysis indicates that the dosimetric differences detected by IQM were significant (p < 0.05) in all PF test deliveries. The largest average IQM signal response of a 2 mm leaf error was found to be 2.1% and 5.1% by a 5mm leaf error for 3×1 cm2 field size. The same error in 24×1 cm2 generates a 0.7% and 1.4% difference in the signal. Conclusion: IQM provides an effective means for real-time dosimetric verification of IMRT/ VMAT treatment delivery. For VMAT delivery, the cumulative dosimetry of IQM needs to be used in clinical practice.« less

Gaps in nuclear spectra as traces of seniority changes in systems of both neutrons and protons

NASA Astrophysics Data System (ADS)

Zamick, Larry

2016-03-01

There has been a great deal of attention given to the low-lying energy spectrum in a nucleus because of the abundance of experimental data. Likewise, perhaps to a lesser extent but still significant, the high end for a given configuration has been examined. Here, using single j shell calculations as a guide, we examine the middle part of the spectrum resulting from single j shell calculations. Seniority arguments are used to partially explain the midshell behaviors even though in general seniority is not a good quantum number for mixed systems of neutrons and protons.

Plasmodium falciparum signal peptide peptidase cleaves malaria heat shock protein 101 (HSP101). Implications for gametocytogenesis

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

Baldwin, Michael; Russo, Crystal; Li, Xuerong

Highlights: • PfSPP is an ER resident protease. • PfSPP is expressed both as a monomer and dimer. • The signal peptide of HSP101 is the first known substrate of PfSPP. • Reduced PfSPP activity may significantly affect ER homeostasis. - Abstract: Previously we described the identification of a Plasmodium falciparum signal peptide peptidase (PfSPP) functioning at the blood stage of malaria infection. Our studies also demonstrated that mammalian SPP inhibitors prevent malaria parasite growth at the late-ring/early trophozoite stage of intra-erythrocytic development. Consistent with its role in development, we tested the hypothesis that PfSPP functions at the endoplasmic reticulummore » of P.falciparum where it cleaves membrane-bound signal peptides generated following the enzyme activity of signal peptidase. The localization of PfSPP to the endoplasmic reticulum was confirmed by immunofluorescence microscopy and immunogold electron microscopy. Biochemical analysis indicated the existence of monomer and dimer forms of PfSPP in the parasite lysate. A comprehensive bioinformatics screen identified several candidate PfSPP substrates in the parasite genome. Using an established transfection based in vivo luminescence assay, malaria heat shock protein 101 (HSP101) was identified as a substrate of PfSPP, and partial inhibition of PfSPP correlated with the emergence of gametocytes. This finding unveils the first known substrate of PfSPP, and provides new perspectives for the function of intra-membrane proteolysis at the erythrocyte stage of malaria parasite life cycle.« less

Molecular identification of lipase LipA from Pseudomonas protegens Pf-5 and characterization of two whole-cell biocatalysts Pf-5 and Top10lipA.

PubMed

Zha, Daiming; Xu, Li; Zhang, Houjin; Yan, Yunjun

2014-05-01

To identify lipase LipA (PFL_0617) from Pseudomonas protegens Pf-5, a lipA deletion mutant (Pf0617) and a complementary strain (Pf0617lipA) were constructed, and their effects on the lipase production were examined. Pf0617 remarkably decreased its whole-cell lipase activity, whereas Pf0617lipA made its whole-cell lipase activity not only restore to wild-type level but also get a further increment. However, the deletion and overexpression of lipA did not affect the extracellular lipase activity. In addition, the unbroken whole cells of these strains were able to catalyze the hydrolysis of membrane-permeable p-nitrophenyl esters, but could not hydrolyze the membrane-impermeable olive oil. These results confirmed that LipA was an intracellular lipase and Pf-5 could also be used as a natural whole-cell biocatalyst. To evaluate the potential of Pf-5 as a whole-cell biocatalyst and separately characterize the whole-cell LipA, the properties of the whole-cell lipases from Pf-5 and Top10lipA were characterized. The results demonstrated that both Pf-5 and Top10lipA exhibited high tolerance to alkaline condition, high temperature, heavy metal ions, surfactants, and organic solvents. Taken together, lipA can realize functional expression in E. coli Top10, and Pf-5 and Top10lipA as whole-cell biocatalysts may have enormous potential in applications.

Multi-micronutrient-fortified biscuits decreased the prevalence of anaemia and improved iron status, whereas weekly iron supplementation only improved iron status in Vietnamese school children.

PubMed

Hieu, Nguyen Trung; Sandalinas, Fanny; de Sesmaisons, Agnès; Laillou, Arnaud; Tam, Nguyen Phuong; Khan, Nguyen Cong; Bruyeron, Olivier; Wieringa, Frank Tammo; Berger, Jacques

2012-10-28

In Vietnam, nutrition interventions do not target school children despite a high prevalence of micronutrient deficiencies. The present randomised, placebo-controlled study evaluated the impact of providing school children (n 403) with daily multiple micronutrient-fortified biscuits (FB) or a weekly Fe supplement (SUP) on anaemia and Fe deficiency. Micronutrient status was assessed by concentrations of Hb, and plasma ferritin (PF), transferrin receptor (TfR), Zn and retinol. After 6 months of intervention, children receiving FB or SUP had a significantly better Fe status when compared with the control children (C), indicated by higher PF (FB: geometric mean 36·9 (95% CI 28·0, 55·4) μg/l; SUP: geometric mean 46·0 (95% CI 33·0, 71·7) μg/l; C: geometric mean 34·4 (95% CI 15·2, 51·2) μg/l; P < 0·001) and lower TfR concentrations (FB: geometric mean 5·7 (95% CI 4·8, 6·52) mg/l; SUP: geometric mean 5·5 (95% CI 4·9, 6·2) mg/l; C: geometric mean 5·9 (95% CI 5·1, 7·1) mg/l; P = 0·007). Consequently, body Fe was higher in children receiving FB (mean 5·6 (sd 2·2) mg/kg body weight) and SUP (mean 6·1 (sd 2·5) mg/kg body weight) compared with the C group (mean 4·2 (sd 3·3) mg/kg body weight, P < 0·001). However, anaemia prevalence was significantly lower only in the FB group (1·0%) compared with the C group (10·4%, P = 0·006), with the SUP group being intermediate (7·4%). Children receiving FB had better weight-for-height Z-scores after the intervention than children receiving the SUP (P = 0·009). Vitamin A deficiency at baseline modified the intervention effect, with higher Hb concentrations in vitamin A-deficient children receiving FB but not in those receiving the SUP. This indicates that vitamin A deficiency is implicated in the high prevalence of anaemia in Vietnamese school children, and that interventions should take other deficiencies besides Fe into account to improve Hb concentrations. Provision of biscuits fortified with multiple micronutrients is effective in reducing anaemia prevalence in school children.

Does strand configuration and number of purchase points affect the biomechanical behavior of a tendon repair? A biomechanical evaluation using different kessler methods of flexor tendon repair.

PubMed

Dogramaci, Yunus; Kalaci, Aydiner; Sevinç, Teoman Toni; Esen, Erdinc; Komurcu, Mahmut; Yanat, Ahmet Nedim

2008-09-01

This study compares the mechanical properties of modified Kessler and double-modified Kessler flexor tendon repair techniques and evaluates simple modifications on both methods. Forty fresh sheep flexor tendons were divided equally into four groups. A transverse sharp cut was done in the middle of each tendon and then repaired with modified Kessler technique, modified Kessler with additional purchase point in the midpoint of each longitudinal strand, double-modified Kessler technique, or a combination of outer Kessler and inner cruciate configuration based on double-modified Kessler technique. The tendons were tested in a tensile testing machine to assess the mechanical performance of the repairs. Outcome measures included gap formation and ultimate forces. The gap strengths of the double-modified Kessler technique (30.85 N, SD 1.90) and double-modified Kessler technique with inner cruciate configuration (33.60 N, SD 4.64) were statistically significantly greater than that of the two-strand modified Kessler (22.56 N, SD 3.44) and modified Kessler with additional purchase configuration (21.75 N, SD 4.03; Tukey honestly significant difference test, P < 0.000). There were statistically significant differences in failure strengths of the all groups (analysis of variance, P < 0.000). With an identical number of strands, the gap formation and ultimate forces of the repairs were not changed by additional locking purchase point in modified Kessler repair or changing the inner strand configuration in double-modified Kessler repair. The results of this study show that the number of strands across the repair site together with the number of locking loops clearly affects the strength of the repair; meanwhile, the longitudinal strand orientation and number of purchase points in a single loop did not affect its strength.

Paeoniflorin inhibits cell growth and induces cell cycle arrest through inhibition of FoxM1 in colorectal cancer cells.

PubMed

Yue, Meng; Li, Shiquan; Yan, Guoqiang; Li, Chenyao; Kang, Zhenhua

2018-01-01

Paeoniflorin (PF) exhibits tumor suppressive functions in a variety of human cancers. However, the function of PF and molecular mechanism in colorectal cancer are elusive. In the present study, we investigated whether PF could exert its antiproliferative activity, anti-migration, and anti-invasive function in colorectal cancer cells. We found that PF inhibited cell growth and induced apoptosis and blocked cell cycle progression in the G0/G1 phase in colorectal cancer cells. Moreover, we found that PF suppressed cell migration and invasion in colorectal cancer cells. FoxM1 has been reported to play an important oncogenic role in human cancers. We also determine whether PF inhibited the expression of FoxM1, leading to its anti-cancer activity. We found that PF treatment in colorectal cancer cells resulted in down-regulation of FoxM1. The rescue experiments showed that overexpression of FoxM1 abrogated the tumor suppressive function induced by PF treatment. Notably, depletion of FoxM1 promoted the anti-tumor activity of PF in colorectal cancer cells. Therefore, inhibition of FoxM1 could participate in the anti-tumor activity of PF in colorectal cancer cells.

Preference for Solitude, Social Isolation, Suicidal Ideation, and Self-Harm in Adolescents.

PubMed

Endo, Kaori; Ando, Shuntaro; Shimodera, Shinji; Yamasaki, Syudo; Usami, Satoshi; Okazaki, Yuji; Sasaki, Tsukasa; Richards, Marcus; Hatch, Stephani; Nishida, Atsushi

2017-08-01

Social isolation is associated with suicidal ideation (SI) and self-harm (SH) among adolescents. However, the association between preference for solitude (PfS), SI, and SH is unknown. The prevalence of adolescents who have both of PfS and social isolation and the risks for SI and SH among them are also unknown. Information on PfS, social isolation, SI, and SH was collected in a large-scale school-based survey on adolescents, using a self-report questionnaire. Associations between PfS, SI, and SH were examined by logistic regression analysis. The interactions between PfS and social isolation on SI and SH were also investigated. The odds of SI and SH were examined for groups defined by presence of PfS and social isolation. Responses from 17,437 students (89.3% of relevant classes) were available. After adjusting for demographic characteristics and social isolation, PfS was associated with increased odds of SI (odds ratio [OR] = 3.1) and SH (OR = 1.9). There was no interaction between PfS and social isolation on SI and SH. After adjusting for demographic characteristics, the odds for SI (OR = 8.6) and SH (OR = 3.8) were highest among adolescents with both PfS and social isolation (8.4% of all respondents). PfS was associated with increased odds of SI and SH in adolescents. No interaction effect between PfS and social isolation on SI and SH was found, but adolescents with PfS and social isolation had the highest risk for SI and SH. Parents and professionals should pay attention to suicide risk in adolescents with PfS. Copyright © 2017 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Progress with Plasmodium falciparum sporozoite (PfSPZ)-based malaria vaccines.

PubMed

Richie, Thomas L; Billingsley, Peter F; Sim, B Kim Lee; James, Eric R; Chakravarty, Sumana; Epstein, Judith E; Lyke, Kirsten E; Mordmüller, Benjamin; Alonso, Pedro; Duffy, Patrick E; Doumbo, Ogobara K; Sauerwein, Robert W; Tanner, Marcel; Abdulla, Salim; Kremsner, Peter G; Seder, Robert A; Hoffman, Stephen L

2015-12-22

Sanaria Inc. has developed methods to manufacture, purify and cryopreserve aseptic Plasmodium falciparum (Pf) sporozoites (SPZ), and is using this platform technology to develop an injectable PfSPZ-based vaccine that provides high-grade, durable protection against infection with Pf malaria. Several candidate vaccines are being developed and tested, including PfSPZ Vaccine, in which the PfSPZ are attenuated by irradiation, PfSPZ-CVac, in which fully infectious PfSPZ are attenuated in vivo by concomitant administration of an anti-malarial drug, and PfSPZ-GA1, in which the PfSPZ are attenuated by gene knockout. Forty-three research groups in 15 countries, organized as the International PfSPZ Consortium (I-PfSPZ-C), are collaborating to advance this program by providing intellectual, clinical, and financial support. Fourteen clinical trials of these products have been completed in the USA, Europe and Africa, two are underway and at least 12 more are planned for 2015-2016 in the US (four trials), Germany (2 trials), Tanzania, Kenya, Mali, Burkina Faso, Ghana and Equatorial Guinea. Sanaria anticipates application to license a first generation product as early as late 2017, initially to protect adults, and a year later to protect all persons >6 months of age for at least six months. Improved vaccine candidates will be advanced as needed until the following requirements have been met: long-term protection against natural transmission, excellent safety and tolerability, and operational feasibility for population-wide administration. Here we describe the three most developed whole PfSPZ vaccine candidates, associated clinical trials, initial plans for licensure and deployment, and long-term objectives for a final product suitable for mass administration to achieve regional malaria elimination and eventual global eradication. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Attenuated PfSPZ Vaccine induces strain-transcending T cells and durable protection against heterologous controlled human malaria infection.

PubMed

Lyke, Kirsten E; Ishizuka, Andrew S; Berry, Andrea A; Chakravarty, Sumana; DeZure, Adam; Enama, Mary E; James, Eric R; Billingsley, Peter F; Gunasekera, Anusha; Manoj, Anita; Li, Minglin; Ruben, Adam J; Li, Tao; Eappen, Abraham G; Stafford, Richard E; Kc, Natasha; Murshedkar, Tooba; Mendoza, Floreliz H; Gordon, Ingelise J; Zephir, Kathryn L; Holman, LaSonji A; Plummer, Sarah H; Hendel, Cynthia S; Novik, Laura; Costner, Pamela J M; Saunders, Jamie G; Berkowitz, Nina M; Flynn, Barbara J; Nason, Martha C; Garver, Lindsay S; Laurens, Matthew B; Plowe, Christopher V; Richie, Thomas L; Graham, Barney S; Roederer, Mario; Sim, B Kim Lee; Ledgerwood, Julie E; Hoffman, Stephen L; Seder, Robert A

2017-03-07

A live-attenuated malaria vaccine, Plasmodium falciparum sporozoite vaccine (PfSPZ Vaccine), confers sterile protection against controlled human malaria infection (CHMI) with Plasmodium falciparum (Pf) parasites homologous to the vaccine strain up to 14 mo after final vaccination. No injectable malaria vaccine has demonstrated long-term protection against CHMI using Pf parasites heterologous to the vaccine strain. Here, we conducted an open-label trial with PfSPZ Vaccine at a dose of 9.0 × 10 5 PfSPZ administered i.v. three times at 8-wk intervals to 15 malaria-naive adults. After CHMI with homologous Pf parasites 19 wk after final immunization, nine (64%) of 14 (95% CI, 35-87%) vaccinated volunteers remained without parasitemia compared with none of six nonvaccinated controls ( P = 0.012). Of the nine nonparasitemic subjects, six underwent repeat CHMI with heterologous Pf7G8 parasites 33 wk after final immunization. Five (83%) of six (95% CI, 36-99%) remained without parasitemia compared with none of six nonvaccinated controls. PfSPZ-specific T-cell and antibody responses were detected in all vaccine recipients. Cytokine production by T cells from vaccinated subjects after in vitro stimulation with homologous (NF54) or heterologous (7G8) PfSPZ were highly correlated. Interestingly, PfSPZ-specific T-cell responses in the blood peaked after the first immunization and were not enhanced by subsequent immunizations. Collectively, these data suggest durable protection against homologous and heterologous Pf parasites can be achieved with PfSPZ Vaccine. Ongoing studies will determine whether protective efficacy can be enhanced by additional alterations in the vaccine dose and number of immunizations.

Progress with Plasmodium falciparum sporozoite (PfSPZ)-based malaria vaccines

PubMed Central

Richie, Thomas L.; Billingsley, Peter F.; Sim, B. Kim Lee; James, Eric R.; Chakravarty, Sumana; Epstein, Judith E.; Lyke, Kirsten E.; Mordmüller, Benjamin; Alonso, Pedro; Duffy, Patrick E.; Doumbo, Ogobara K.; Sauerwein, Robert W.; Tanner, Marcel; Abdulla, Salim; Kremsner, Peter G.; Seder, Robert A.; Hoffman, Stephen L.

2016-01-01

Sanaria Inc. has developed methods to manufacture, purify and cryopreserve aseptic Plasmodium falciparum (Pf) sporozoites (SPZ), and is using this platform technology to develop an injectable PfSPZ-based vaccine that provides high-grade, durable protection against infection with Pf malaria. Several candidate vaccines are being developed and tested, including PfSPZ Vaccine, in which the PfSPZ are attenuated by irradiation, PfSPZ-CVac, in which fully infectious PfSPZ are attenuated in vivo by concomitant administration of an anti-malarial drug, and PfSPZ-GA1, in which the PfSPZ are attenuated by gene knockout. Forty-three research groups in 15 countries, organized as the International PfSPZ Consortium (I-PfSPZ-C), are collaborating to advance this program by providing intellectual, clinical, and financial support. Fourteen clinical trials of these products have been completed in the USA, Europe and Africa, two are underway and at least 12 more are planned for 2015–2016 in the US (four trials), Germany (2 trials), Tanzania, Kenya, Mali, Burkina Faso, Ghana and Equatorial Guinea. Sanaria anticipates application to license a first generation product as early as late 2017, initially to protect adults, and a year later to protect all persons >6 months of age for at least six months. Improved vaccine candidates will be advanced as needed until the following requirements have been met: long-term protection against natural transmission, excellent safety and tolerability, and operational feasibility for population-wide administration. Here we describe the three most developed whole PfSPZ vaccine candidates, associated clinical trials, initial plans for licensure and deployment, and long-term objectives for a final product suitable for mass administration to achieve regional malaria elimination and eventual global eradication. PMID:26469720

Peritoneal fluid from endometriosis patients switches differentiation of monocytes from dendritic cells to macrophages.

PubMed

Na, Yong-Jin; Jin, Jun-O; Lee, Mi-Sook; Song, Min-Gyu; Lee, Kyu-Sup; Kwak, Jong-Young

2008-01-01

Immunological abnormalities of cell-mediated and humoral immunity might be associated with the pathogenesis of endometriosis. This study has examined the effects of peritoneal fluid obtained from patients with endometriosis (ePF) on the phenotypic characteristics of macrophages and dendritic cells (DCs) derived from monocytes. Monocytes were obtained from healthy young volunteers and cultured with ePF (n=12) or a control PF (cPF) (n=5) in the presence or absence of macrophage-colony stimulating factor (M-CSF) or IL-4 plus granulocyte macrophage-colony stimulating factor (GM-CSF). The ePF was demonstrated to increase expression levels of CD14 and CD64 on isolated monocytes in the presence or absence of M-CSF. Compared with cPF, addition of 10% ePF to GM-CSF plus IL-4-treated monocytes significantly down-regulated CD1a expression and up-regulated CD64 expression, but did not enhance expression levels of class II MHC. ePF had no effect, however, on tumor necrosis factor-alpha-induced maturation of DC. Levels of IL-6, IL-10 and M-CSF production were higher in ePF-treated than cPF-treated monocytes for both cell culture conditions with GM-CSF plus IL-4 and M-CSF. A neutralizing IL-6 antibody, but not an IL-10 antibody, abrogated the ePF-induced down-regulation of CD1a, up-regulation of CD64 and secretion of M-CSF. These results suggest that ePF favorably induces monocyte differentiation toward macrophages rather than DCs, and that this effect is mediated by IL-6. A reciprocal mode of cell differentiation between macrophages and DCs in response to ePF may be related to the pathogenesis of endometriosis.

The antigenic complex in HIT binds to B cells via complement and complement receptor 2 (CD21)

PubMed Central

Khandelwal, Sanjay; Lee, Grace M.; Hester, C. Garren; Poncz, Mortimer; McKenzie, Steven E.; Sachais, Bruce S.; Rauova, Lubica; Kelsoe, Garnett; Cines, Douglas B.; Frank, Michael

2016-01-01

Heparin-induced thrombocytopenia is a prothrombotic disorder caused by antibodies to platelet factor 4 (PF4)/heparin complexes. The mechanism that incites such prevalent anti-PF4/heparin antibody production in more than 50% of patients exposed to heparin in some clinical settings is poorly understood. To investigate early events associated with antigen exposure, we first examined the interaction of PF4/heparin complexes with cells circulating in whole blood. In healthy donors, PF4/heparin complexes bind preferentially to B cells (>90% of B cells bind to PF4/heparin in vitro) relative to neutrophils, monocytes, or T cells. Binding of PF4 to B cells is heparin dependent, and PF4/heparin complexes are found on circulating B cells from some, but not all, patients receiving heparin. Given the high proportion of B cells that bind PF4/heparin, we investigated complement as a mechanism for noncognate antigen recognition. Complement is activated by PF4/heparin complexes, co-localizes with antigen on B cells from healthy donors, and is present on antigen-positive B cells in patients receiving heparin. Binding of PF4/heparin complexes to B cells is mediated through the interaction between complement and complement receptor 2 (CR2 [CD21]). To the best of our knowledge, these are the first studies to demonstrate complement activation by PF4/heparin complexes, opsonization of PF4/heparin to B cells via CD21, and the presence of complement activation fragments on circulating B cells in some patients receiving heparin. Given the critical contribution of complement to humoral immunity, our observations provide new mechanistic insights into the immunogenicity of PF4/heparin complexes. PMID:27412887

Comparison of breaking strength and shell thickness as evaluators of white-faced ibis eggshell quality

USGS Publications Warehouse

Henny, C.J.; Bennett, J.K.

1990-01-01

Data from a 1986 field study of white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada, were used to compare the utility of eggshell strength measurement and eggshell thickness as indicators of eggshell quality. The ibis population had a history of reproductive failure correlated with elevated egg concentrations of p,p`DDE, hereafter referred to as DDE. Eggs from 80 nests (one egg/nest) were tested for shell strength and thickness. Egg contents were analyzed for organochlorines, mercury and selenium; productivity at each nest (minus one egg) was monitored in the field. DDE-DDT concentrations in the eggs ranged from none detected (less than 0.1) to 29 ppm (wet weight). Shell thickness and shell strength were both negatively correlated with DDE (0.60, 0.61, respectively), but shell strength deteriorated at a faster rate than shell thickness. Scanning electron micrographs indicated the deterioration in strength was related to changes in ultrastructure as well as to decreased thickness. Fourteen eggs with less than 0.40 ppm DDE were used to exemplify normal control eggs. Of the eggs with higher concentrations of DDE (i.e., greater than or equal to 0.40 ppm), 11 of 66 were thinner (greater than 2 SD below 'control' mean) than normal, 11 of 59 were weaker than normal and 7 eggs were cracked so their strength could not be tested, although thickness was measured. Therefore, 17% of the eggs with greater than or equal to 0.40 ppm DDE were thinner than normal and 27% were either weaker than normal or cracked. Further, six eggs (four with greater than or equal to 15 ppm DDE) did not have abnormally thin shells, but did have abnormally weak shells. Nests with abnormal test eggs (thinner, weaker or cracked) produced fewer young than nests with normal eggs. Use of the shell strength parameter provides additional information for better evaluations of reproductive problems. The potential utility of monitoring eggshell quality goes beyond evaluating effects of organochlorines since recent work indicates that other environmental hazards can affect shell quality.

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

Clausen, Drew; Wade, Richard A.; Kopparapu, Ravi Kumar

Binaries that contain a hot subdwarf (sdB) star and a main-sequence companion may have interacted in the past. This binary population has historically helped determine our understanding of binary stellar evolution. We have computed a grid of binary population synthesis models using different assumptions about the minimum core mass for helium ignition, the envelope binding energy, the common-envelope ejection efficiency, the amount of mass and angular momentum lost during stable mass transfer, and the criteria for stable mass transfer on the red giant branch and in the Hertzsprung gap. These parameters separately and together can significantly change the entire predictedmore » population of sdBs. Nonetheless, several different parameter sets can reproduce the observed subpopulation of sdB + white dwarf and sdB + M dwarf binaries, which has been used to constrain these parameters in previous studies. The period distribution of sdB + early F dwarf binaries offers a better test of different mass transfer scenarios for stars that fill their Roche lobes on the red giant branch.« less

The Malaria Parasite Cyclin H Homolog PfCyc1 Is Required for Efficient Cytokinesis in Blood-Stage Plasmodium falciparum.

PubMed

Robbins, Jonathan A; Absalon, Sabrina; Streva, Vincent A; Dvorin, Jeffrey D

2017-06-13

All well-studied eukaryotic cell cycles are driven by cyclins, which activate cyclin-dependent kinases (CDKs), and these protein kinase complexes are viable drug targets. The regulatory control of the Plasmodium falciparum cell division cycle remains poorly understood, and the roles of the various CDKs and cyclins remain unclear. The P. falciparum genome contains multiple CDKs, but surprisingly, it does not contain any sequence-identifiable G 1 -, S-, or M-phase cyclins. We demonstrate that P. falciparum Cyc1 (PfCyc1) complements a G 1 cyclin-depleted Saccharomyces cerevisiae strain and confirm that other identified malaria parasite cyclins do not complement this strain. PfCyc1, which has the highest sequence similarity to the conserved cyclin H, cannot complement a temperature-sensitive yeast cyclin H mutant. Coimmunoprecipitation of PfCyc1 from P. falciparum parasites identifies PfMAT1 and PfMRK as specific interaction partners and does not identify PfPK5 or other CDKs. We then generate an endogenous conditional allele of PfCyc1 in blood-stage P. falciparum using a destabilization domain (DD) approach and find that PfCyc1 is essential for blood-stage proliferation. PfCyc1 knockdown does not impede nuclear division, but it prevents proper cytokinesis. Thus, we demonstrate that PfCyc1 has a functional divergence from bioinformatic predictions, suggesting that the malaria parasite cell division cycle has evolved to use evolutionarily conserved proteins in functionally novel ways. IMPORTANCE Human infection by the eukaryotic parasite Plasmodium falciparum causes malaria. Most well-studied eukaryotic cell cycles are driven by cyclins, which activate cyclin-dependent kinases (CDKs) to promote essential cell division processes. Remarkably, there are no identifiable cyclins that are predicted to control the cell cycle in the malaria parasite genome. Thus, our knowledge regarding the basic mechanisms of the malaria parasite cell cycle remains unsatisfactory. We demonstrate that P. falciparum Cyc1 (PfCyc1), a transcriptional cyclin homolog, complements a cell cycle cyclin-deficient yeast strain but not a transcriptional cyclin-deficient strain. We show that PfCyc1 forms a complex in the parasite with PfMRK and the P. falciparum MAT1 homolog. PfCyc1 is essential and nonredundant in blood-stage P. falciparum PfCyc1 knockdown causes a stage-specific arrest after nuclear division, demonstrating morphologically aberrant cytokinesis. This work demonstrates a conserved PfCyc1/PfMAT1/PfMRK complex in malaria and suggests that it functions as a schizont stage-specific regulator of the P. falciparum life cycle. Copyright © 2017 Robbins et al.

Electrically heated particulate filter using catalyst striping

DOEpatents

Gonze, Eugene V; Paratore, Jr., Michael J; Ament, Frank

2013-07-16

An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material is applied to an exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF. A catalyst coating is applied to the PF that increases a temperature of the combustion of the particulates within the PF.

Pulmonary 18F-FDG uptake helps refine current risk stratification in idiopathic pulmonary fibrosis (IPF).

PubMed

Win, Thida; Screaton, Nicholas J; Porter, Joanna C; Ganeshan, Balaji; Maher, Toby M; Fraioli, Francesco; Endozo, Raymondo; Shortman, Robert I; Hurrell, Lynn; Holman, Beverley F; Thielemans, Kris; Rashidnasab, Alaleh; Hutton, Brian F; Lukey, Pauline T; Flynn, Aiden; Ell, Peter J; Groves, Ashley M

2018-05-01

There is a lack of prognostic biomarkers in idiopathic pulmonary fibrosis (IPF) patients. The objective of this study is to investigate the potential of 18 F-FDG-PET/ CT to predict mortality in IPF. A total of 113 IPF patients (93 males, 20 females, mean age ± SD: 70 ± 9 years) were prospectively recruited for 18 F-FDG-PET/CT. The overall maximum pulmonary uptake of 18 F-FDG (SUV max ), the minimum pulmonary uptake or background lung activity (SUV min ), and target-to-background (SUV max / SUV min ) ratio (TBR) were quantified using routine region-of-interest analysis. Kaplan-Meier analysis was used to identify associations of PET measurements with mortality. We also compared PET associations with IPF mortality with the established GAP (gender age and physiology) scoring system. Cox analysis assessed the independence of the significant PET measurement(s) from GAP score. We investigated synergisms between pulmonary 18 F-FDG-PET measurements and GAP score for risk stratification in IPF patients. During a mean follow-up of 29 months, there were 54 deaths. The mean TBR ± SD was 5.6 ± 2.7. Mortality was associated with high pulmonary TBR (p = 0.009), low forced vital capacity (FVC; p = 0.001), low transfer factor (TLCO; p < 0.001), high GAP index (p = 0.003), and high GAP stage (p = 0.003). Stepwise forward-Wald-Cox analysis revealed that the pulmonary TBR was independent of GAP classification (p = 0.010). The median survival in IPF patients with a TBR < 4.9 was 71 months, whilst in those with TBR > 4.9 was 24 months. Combining PET data with GAP data ("PET modified GAP score") refined the ability to predict mortality. A high pulmonary TBR is independently associated with increased risk of mortality in IPF patients.

Telling Stories and Making Books: Evidence for an Intervention to Help Parents in Migrant Head Start Families Support Their Children's Language and Literacy

ERIC Educational Resources Information Center

Boyce, Lisa K.; Innocenti, Mark S.; Roggman, Lori A.; Norman, Vonda K. Jump; Ortiz, Eduardo

2010-01-01

Research Findings: In this study, 75 Spanish-speaking preschoolers (M age = 41.43 months, SD = 10.78 months; 30 girls) attending a Migrant Head Start program were randomly assigned to receive the Storytelling for the Home Enrichment of Language and Literacy Skills (SHELLS) in addition to their Head Start services (n = 32) or to continue to receive…

The characterization of obese polycystic ovary syndrome rat model suitable for exercise intervention.

PubMed

Wu, Chuyan; Lin, Feng; Qiu, Shuwei; Jiang, Zhongli

2014-01-01

To develop a new polycystic ovary syndrome (PCOS) rat model suitable for exercise intervention. Thirty six rats were randomly divided into three experimental groups: PCOS rats with high-fat diet (PF, n = 24), PCOS rats with ordinary diet (PO, n = 6), and control rats with ordinary diet (CO, n = 6). Two kinds of PCOS rat model were made by adjustment diet structure and testosterone injection for 28 days. After a successful animal model, PF model rats were randomly assigned to three groups: exercise with a continuation of high-fat diet (PF-EF, n = 6), sedentary with a continuation of high-fat diet (PF-SF, n = 6), exercise with an ordinary diet (PF-EO, n = 6). Fasting blood glucose (FBG) and insulin (FINS), estrogen (E2), progesterone (P), and testosterone (T) in serum were determined by RIA, and ovarian morphology was evaluated by Image-Pro plus 6.0. Body weight, Lee index, FINS increased significantly in PF rat model. Serum levels of E2 and T were significantly higher in PF and PO than in CO. Ovary organ index and ovarian areas were significant lower in PF than in CO. After intervention for 2 weeks, the levels of 1 h postprandial blood glucose (PBG1), 2 h postprandial blood glucose (PBG2), FINS and the serum levels of T decreased significantly in PF-EF rats and PF-EO rats. The ratio of FBG/FINS was significant higher in PF-EO rats than in PF-SF rats. Ovarian morphology showed that the numbers of preantral follicles and atretic follicles decreased significantly, and the numbers of antral follicles and corpora lutea increased significantly in the rats of PF-EF and PF-EO. By combination of high-fat diet and testosterone injection, the obese PCOS rat model is conformable with the lifestyle habits of fatty foods and insufficient exercise, and has metabolic and reproductive characteristics of human PCOS. This model can be applied to study exercise intervention.

Plasmodium falciparum chloroquine resistance transporter (PfCRT) isoforms PH1 and PH2 perturb vacuolar physiology.

PubMed

Callaghan, Paul S; Siriwardana, Amila; Hassett, Matthew R; Roepe, Paul D

2016-03-31

Recent work has perfected yeast-based methods for measuring drug transport by the Plasmodium falciparum chloroquine (CQ) resistance transporter (PfCRT). The approach relies on inducible heterologous expression of PfCRT in Saccharomyces cerevisiae yeast. In these experiments selecting drug concentrations are not toxic to the yeast, nor is expression of PfCRT alone toxic. Only when PfCRT is expressed in the presence of CQ is the growth of yeast impaired, due to inward transport of chloroquine (CQ) via the transporter. During analysis of all 53 known naturally occurring PfCRT isoforms, two isoforms (PH1 and PH2 PfCRT) were found to be intrinsically toxic to yeast, even in the absence of CQ. Additional analysis of six very recently identified PfCRT isoforms from Malaysia also showed some toxicity. In this paper the nature of this yeast toxicity is examined. Data also show that PH1 and PH2 isoforms of PfCRT transport CQ with an efficiency intermediate to that catalyzed by previously studied CQR conferring isoforms. Mutation of PfCRT at position 160 is found to perturb vacuolar physiology, suggesting a fitness cost to position 160 amino acid substitutions. These data further define the wide range of activities that exist for PfCRT isoforms found in P. falciparum isolates from around the globe.

Modification of the lipid moiety of the enterobacterial common antigen by the "Pseudomonas factor".

PubMed Central

Kuhn, H M; Neter, E; Mayer, H

1983-01-01

Pseudomonas aeruginosa produces a factor (PF) which affects the enterobacterial common antigen (ECA); resulting in failure of the antigen to modify erythrocytes for hemagglutination by ECA antibodies. In the present study the nature of PF was determined. Pronase treatment abolished its activity, indicating the protein nature of PF. PF-treated ECA no longer coated erythrocytes but still reacted with ECA antibodies in immunoelectrophoresis tests with monospecific antiserum to ECA, although differences were noted between the precipitation patterns of PF-treated and untreated ECA. Therefore, PF does not significantly affect the antigenic determinant of ECA but rather affects its lipid carrier, an L-glycerophosphatide. Accordingly, differences in the sugar chain could not be detected by high-voltage paper electrophoretic examinations of partial hydrolysates of PF-treated and untreated ECA. PF liberates all fatty acids from ECA, similarly to commercial lipases, as evidenced by the liberation of unsubstituted glycerol upon HF degradation at 0 degrees C of PF-treated ECA. The lipase activity of PF is indicated also by the observation that a strain of P. aeruginosa with reduced lipase production and an exolipase-negative strain affect ECA either less or not at all. We conclude that PF is a lipase acting on the lipid moiety of ECA, which is responsible for the coating of erythrocytes, but not significantly on the serological determinant, the amino sugar chain. Images PMID:6404831

PROMIS Physical Function Computer Adaptive Test Compared With Other Upper Extremity Outcome Measures in the Evaluation of Proximal Humerus Fractures in Patients Older Than 60 Years.

PubMed

Morgan, Jordan H; Kallen, Michael A; Okike, Kanu; Lee, Olivia C; Vrahas, Mark S

2015-06-01

To compare the PROMIS Physical Function Computer Adaptive Test (PROMIS PF CAT) to commonly used traditional PF measures for the evaluation of patients with proximal humerus fractures. Prospective. Two Level I trauma centers. Forty-seven patients older than 60 years with displaced proximal humerus fractures treated between 2006 and 2009. Evaluation included completion of the PROMIS PF CAT, the Constant Shoulder Score, the Disabilities of the Arm, Shoulder, and Hand (DASH) and the Short Musculoskeletal Functional Assessment (SMFA). Observed correlations among the administered PF outcome measures. On average, patients responded to 86 outcome-related items for this study: 4 for the PROMIS PF CAT (range: 4-8 items), 6 for the Constant Shoulder Score, 30 for the DASH, and 46 for the SMFA. Time to complete the PROMIS PF CAT (median completion time = 98 seconds) was significantly less than that for the DASH (median completion time = 336 seconds, P < 0.001) and for the SMFA (median completion time = 482 seconds, P < 0.001). PROMIS PF CAT scores correlated statistically significantly and were of moderate-to-high magnitude with all other PF outcome measure scores administered. This study suggests using the PROMIS PF CAT as a sole PF outcome measure can yield an assessment of upper extremity function similar to those provided by traditional PF measures, while substantially reducing patient assessment time.

High resolution observations of Cassiopeia A at meter wavelengths. [pulsar source in supernova remnant

NASA Technical Reports Server (NTRS)

Hutton, L. K.; Clark, T. A.; Erickson, W. C.; Resch, G. M.; Vandenberg, N. R.; Knowles, S. H.; Youmans, A. B.

1974-01-01

Very long baseline interferometric (VLBI) observations of the supernova remnant Cassiopeia A, at 74 MHz with a 12,000-wavelength baseline and at 111 MHz with a 18,500-wavelength baseline, are reported. The fringe amplitudes are strongly varying on a time scale of about 15 to 30 minutes. The location of the extra source must lie outside the supernova remnant shell possibly associated with a concentration of emission north of the shell, or lying outside the gap in the northeastern side of the shell. The flux and spectral index deduced for the compact source depend on the assumed size, with a range of 100 Jy to 500 Jy at 74 MHz. If the source is associated with the supernova explosion, it must have been traveling at least 5000 km s/2.

Theory of the disordered ν =5/2 quantum thermal Hall state: Emergent symmetry and phase diagram

NASA Astrophysics Data System (ADS)

Lian, Biao; Wang, Juven

2018-04-01

Fractional quantum Hall (FQH) system at Landau level filling fraction ν =5 /2 has long been suggested to be non-Abelian, either Pfaffian (Pf) or antiPfaffian (APf) states by numerical studies, both with quantized Hall conductance σx y=5 e2/2 h . Thermal Hall conductances of the Pf and APf states are quantized at κx y=7 /2 and κx y=3 /2 , respectively, in a proper unit. However, a recent experiment shows the thermal Hall conductance of ν =5 /2 FQH state is κx y=5 /2 . It has been speculated that the system contains random Pf and APf domains driven by disorders, and the neutral chiral Majorana modes on the domain walls may undergo a percolation transition to a κx y=5 /2 phase. In this paper, we do perturbative and nonperturbative analyses on the domain walls between Pf and APf. We show the domain wall theory possesses an emergent SO(4) symmetry at energy scales below a threshold Λ1, which is lowered to an emergent U (1 )×U (1) symmetry at energy scales between Λ1 and a higher value Λ2, and is finally lowered to the composite fermion parity symmetry Z2F above Λ2. Based on the emergent symmetries, we propose a phase diagram of the disordered ν =5 /2 FQH system and show that a κx y=5 /2 phase arises at disorder energy scales Λ >Λ1 . Furthermore, we show the gapped double-semion sector of ND compact domain walls contributes nonlocal topological degeneracy 2ND-1, causing a low-temperature peak in the heat capacity. We implement a nonperturbative method to bootstrap generic topological 1 +1 D domain walls (two-surface defects) applicable to any 2 +1 D non-Abelian topological order. We also identify potentially relevant spin topological quantum field theories (TQFTs) for various ν =5 /2 FQH states in terms of fermionic version of U (1) ±8 Chern-Simons theory ×Z8 -class TQFTs.

PbSe-Based Colloidal Core/Shell Heterostructures for Optoelectronic Applications

PubMed Central

Zaiats, Gary; Yanover, Diana; Vaxenburg, Roman; Tilchin, Jenya; Sashchiuk, Aldona; Lifshitz, Efrat

2014-01-01

Lead-based (IV–VI) colloidal quantum dots (QDs) are of widespread scientific and technological interest owing to their size-tunable band-gap energy in the near-infrared optical region. This article reviews the synthesis of PbSe-based heterostructures and their structural and optical investigations at various temperatures. The review focuses on the structures consisting of a PbSe core coated with a PbSexS1–x (0 ≤ x ≤ 1) or CdSe shell. The former-type shells were epitaxially grown on the PbSe core, while the latter-type shells were synthesized using partial cation-exchange. The influence of the QD composition and the ambient conditions, i.e., exposure to oxygen, on the QD optical properties, such as radiative lifetime, Stokes shift, and other temperature-dependent characteristics, was investigated. The study revealed unique properties of core/shell heterostructures of various compositions, which offer the opportunity of fine-tuning the QD electronic structure by changing their architecture. A theoretical model of the QD electronic band structure was developed and correlated with the results of the optical studies. The review also outlines the challenges related to potential applications of colloidal PbSe-based heterostructures. PMID:28788244

Imaging of plantar fascia disorders: findings on plain radiography, ultrasound and magnetic resonance imaging.

PubMed

Draghi, Ferdinando; Gitto, Salvatore; Bortolotto, Chandra; Draghi, Anna Guja; Ori Belometti, Gioia

2017-02-01

Plantar fascia (PF) disorders commonly cause heel pain and disability in the general population. Imaging is often required to confirm diagnosis. This review article aims to provide simple and systematic guidelines for imaging assessment of PF disease, focussing on key findings detectable on plain radiography, ultrasound and magnetic resonance imaging (MRI). Sonographic characteristics of plantar fasciitis include PF thickening, loss of fibrillar structure, perifascial collections, calcifications and hyperaemia on Doppler imaging. Thickening and signal changes in the PF as well as oedema of adjacent soft tissues and bone marrow can be assessed on MRI. Radiographic findings of plantar fasciitis include PF thickening, cortical irregularities and abnormalities in the fat pad located deep below the PF. Plantar fibromatosis appears as well-demarcated, nodular thickenings that are iso-hypoechoic on ultrasound and show low-signal intensity on MRI. PF tears present with partial or complete fibre interruption on both ultrasound and MRI. Imaging description of further PF disorders, including xanthoma, diabetic fascial disease, foreign-body reactions and plantar infections, is detailed in the main text. Ultrasound and MRI should be considered as first- and second-line modalities for assessment of PF disorders, respectively. Indirect findings of PF disease can be ruled out on plain radiography. Teaching Points • PF disorders commonly cause heel pain and disability in the general population.• Imaging is often required to confirm diagnosis or reveal concomitant injuries.• Ultrasound and MRI respectively represent the first- and second-line modalities for diagnosis.• Indirect findings of PF disease can be ruled out on plain radiography.

Comparative study of flexural strength test methods on CAD/CAM Y-TZP dental ceramics

PubMed Central

Xu, Yongxiang; Han, Jianmin; Lin, Hong; An, Linan

2015-01-01

Clinically, fractures are the main cause of computer-aided design and computer-aided manufacturing (CAD/CAM) 3 mol%-yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) all-ceramic dental restorations failure because of repetitive occlusal loading. The goal of this work is to study the effect of test methods and specimen’s size on the flexural strength of five ceramic products. Both bi-axial flexure test (BI) and uni-axial flexure tests (UNI), including three-point flexure test (3PF) and four-point flexure test (4PF), are used in this study. For all five products, the flexural strength is as follows: BI > 3PF > 4PF. Furthermore, specimens with smaller size (3PF-s) have higher values than the bigger ones (3PF). The difference between BI and UNI resulted from the edge flaws in ceramic specimens. The relationship between different UNI (including 3PF-s, 3PF and 4PF) can be explained according to Weibull statistical fracture theory. BI is recommended to evaluate the flexural strength of CAD/CAM Y-TZP dental ceramics. PMID:26816646

Cavity method for force transmission in jammed disordered packings of hard particles.

PubMed

Bo, Lin; Mari, Romain; Song, Chaoming; Makse, Hernán A

2014-10-07

The force distribution of jammed disordered packings has always been considered a central object in the physics of granular materials. However, many of its features are poorly understood. In particular, analytic relations to other key macroscopic properties of jammed matter, such as the contact network and its coordination number, are still lacking. Here we develop a mean-field theory for this problem, based on the consideration of the contact network as a random graph where the force transmission becomes a constraint satisfaction problem. We can thus use the cavity method developed in the past few decades within the statistical physics of spin glasses and hard computer science problems. This method allows us to compute the force distribution P(f) for random packings of hard particles of any shape, with or without friction. We find a new signature of jamming in the small force behavior P(f) ∼ f(θ), whose exponent has attracted recent active interest: we find a finite value for P(f = 0), along with θ = 0. Furthermore, we relate the force distribution to a lower bound of the average coordination number z[combining macron](μ) of jammed packings of frictional spheres with coefficient μ. This bridges the gap between the two known isostatic limits z[combining macron]c (μ = 0) = 2D (in dimension D) and z[combining macron]c(μ → ∞) = D + 1 by extending the naive Maxwell's counting argument to frictional spheres. The theoretical framework describes different types of systems, such as non-spherical objects in arbitrary dimensions, providing a common mean-field scenario to investigate force transmission, contact networks and coordination numbers of jammed disordered packings.

Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy.

PubMed

Liu, Sha; Zhou, Yefei; Xing, Xiaolei; Wang, Jibo; Ren, Xuejun; Yang, Qingxiang

2016-09-06

The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process.

Multi-domain electromagnetic absorption of triangular quantum rings

NASA Astrophysics Data System (ADS)

Sitek, Anna; Thorgilsson, Gunnar; Gudmundsson, Vidar; Manolescu, Andrei

2016-06-01

We present a theoretical study of the unielectronic energy spectra, electron localization, and optical absorption of triangular core-shell quantum rings. We show how these properties depend on geometric details of the triangle, such as side thickness or corners’ symmetry. For equilateral triangles, the lowest six energy states (including spin) are grouped in an energy shell, are localized only around corner areas, and are separated by a large energy gap from the states with higher energy which are localized on the sides of the triangle. The energy levels strongly depend on the aspect ratio of the triangle sides, i.e., thickness/length ratio, in such a way that the energy differences are not monotonous functions of this ratio. In particular, the energy gap between the group of states localized in corners and the states localized on the sides strongly decreases with increasing the side thickness, and then slightly increases for thicker samples. With increasing the thickness the low-energy shell remains distinct but the spatial distribution of these states spreads. The behavior of the energy levels and localization leads to a thickness-dependent absorption spectrum where one transition may be tuned in the THz domain and a second transition can be tuned from THz to the infrared range of electromagnetic spectrum. We show how these features may be further controlled with an external magnetic field. In this work the electron-electron Coulomb repulsion is neglected.

Multi-domain electromagnetic absorption of triangular quantum rings.

PubMed

Sitek, Anna; Thorgilsson, Gunnar; Gudmundsson, Vidar; Manolescu, Andrei

2016-06-03

We present a theoretical study of the unielectronic energy spectra, electron localization, and optical absorption of triangular core-shell quantum rings. We show how these properties depend on geometric details of the triangle, such as side thickness or corners' symmetry. For equilateral triangles, the lowest six energy states (including spin) are grouped in an energy shell, are localized only around corner areas, and are separated by a large energy gap from the states with higher energy which are localized on the sides of the triangle. The energy levels strongly depend on the aspect ratio of the triangle sides, i.e., thickness/length ratio, in such a way that the energy differences are not monotonous functions of this ratio. In particular, the energy gap between the group of states localized in corners and the states localized on the sides strongly decreases with increasing the side thickness, and then slightly increases for thicker samples. With increasing the thickness the low-energy shell remains distinct but the spatial distribution of these states spreads. The behavior of the energy levels and localization leads to a thickness-dependent absorption spectrum where one transition may be tuned in the THz domain and a second transition can be tuned from THz to the infrared range of electromagnetic spectrum. We show how these features may be further controlled with an external magnetic field. In this work the electron-electron Coulomb repulsion is neglected.

In-plane, commensurate GaN/AlN junctions: single-layer composite structures, multiple quantum wells and quantum dots

NASA Astrophysics Data System (ADS)

Durgun, Engin; Onen, Abdullatif; Kecik, Deniz; Ciraci, Salim

In-plane composite structures constructed of the stripes or core/shells of single-layer GaN and AlN, which are joined commensurately display diversity of electronic properties, that can be tuned by the size of their constituents. In heterostructures, the dimensionality of electrons change from 2D to 1D upon their confinements in wide constituent stripes leading to the type-I band alignment and hence multiple quantum well structure in the direct space. The δ-doping of one wide stripe by other narrow stripe results in local narrowing or widening of the band gap. The direct-indirect transition of the fundamental band gap of composite structures can be attained depending on the odd or even values of formula unit in the armchair edged heterojunction. In a patterned array of GaN/AlN core/shells, the dimensionality of the electronic states are reduced from 2D to 0D forming multiple quantum dots in large GaN-cores, while 2D electrons propagate in multiply connected AlN shell as if they are in a supercrystal. These predictions are obtained from first-principles calculations based on density functional theory on single-layer GaN and AlN compound semiconductors which were synthesized recently. This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under Project No 115F088.

Growth characteristics of primary M7C3 carbide in hypereutectic Fe-Cr-C alloy

PubMed Central

Liu, Sha; Zhou, Yefei; Xing, Xiaolei; Wang, Jibo; Ren, Xuejun; Yang, Qingxiang

2016-01-01

The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observed by confocal laser microscope (CLM). It is found that the primary M7C3 carbide in hypereutectic Fe-Cr-C alloy is irregular polygonal shape with several hollows in the center and gaps on the edge. Some primary M7C3 carbides are formed by layers of shell or/and consist of multiple parts. In the initial growth period, the primary M7C3 carbide forms protrusion parallel to {} crystal planes. The extending and revolving protrusion forms the carbide shell. The electron backscattered diffraction (EBSD) maps show that the primary M7C3 carbide consists of multiple parts. The semi-molten M7C3 carbide contains unmelted shell and several small-scale carbides inside, which further proves that the primary M7C3 carbide is not an overall block. It is believed that the coalescence of the primary M7C3 carbides is ascribed to the growing condition of the protrusion and the gap filling process. PMID:27596718

Microscopic description of quadrupole collectivity in neutron-rich nuclei across the N = 126 shell closure

NASA Astrophysics Data System (ADS)

Rodríguez-Guzmán, R.; Robledo, L. M.; Sharma, M. M.

2015-06-01

The quadrupole collectivity in Nd, Sm, Gd, Dy, Er, Yb, Hf and W nuclei with neutron numbers 122 ≤ N ≤ 156 is studied, both at the mean field level and beyond, using the Gogny energy density functional. Besides the robustness of the N = 126 neutron shell closure, it is shown that the onset of static deformations in those isotopic chains with increasing neutron number leads to an enhanced stability and further extends the corresponding two-neutron drip lines far beyond what could be expected from spherical calculations. Independence of the mean-field predictions with respect to the particular version of the Gogny energy density functional employed is demonstrated by comparing results based on the D1S and D1M parameter sets. Correlations beyond mean field are taken into account in the framework of the angular momentum projected generator coordinate method calculation. It is shown that N = 126 remains a robust neutron magic number when dynamical effects are included. The analysis of the collective wave functions, average deformations and excitation energies indicate that, with increasing neutron number, the zero-point quantum corrections lead to dominant prolate configurations in the 0{1/+}, 0{2/+}, 2{1/+} and 2{2/+} states of the studied nuclei. Moreover, those dynamical deformation effects provide an enhanced stability that further supports the mean-field predictions, corroborating a shift of the r-process path to higher neutron numbers. Beyond mean-field calculations provide a smaller shell gap at N = 126 than the mean-field one in good agreement with previous theoretical studies. However, the shell gap still remains strong enough in the two-neutron drip lines.

A Weighted Measurement Fusion Particle Filter for Nonlinear Multisensory Systems Based on Gauss–Hermite Approximation

PubMed Central

Li, Yun

2017-01-01

We addressed the fusion estimation problem for nonlinear multisensory systems. Based on the Gauss–Hermite approximation and weighted least square criterion, an augmented high-dimension measurement from all sensors was compressed into a lower dimension. By combining the low-dimension measurement function with the particle filter (PF), a weighted measurement fusion PF (WMF-PF) is presented. The accuracy of WMF-PF appears good and has a lower computational cost when compared to centralized fusion PF (CF-PF). An example is given to show the effectiveness of the proposed algorithms. PMID:28956862

Clinical impact of culture-positive preservation fluid on solid organ transplantation: A systematic review and meta-analysis.

PubMed

Oriol, Isabel; Sabé, N; Tebé, C; Veroux, M; Boin, I F S F; Carratalà, J

2018-04-01

Contamination of the preservation fluid (PF) used for donated organs is a potential source of post-transplant infection. However, the information on this issue is scarce. We therefore conducted a systematic review and meta-analysis to assess the incidence of culture-positive PF and its impact on solid organ transplant (SOT) recipients. Seventeen studies were identified and included. The overall incidence of culture-positive PF was 37% (95% CI: 27% to 49%), and the incidence of PF-related infections among SOT recipients with PF cultures that grew pathogenic microorganisms was 10% (95% CI: 7% to 15%). There were differences in the rates of infections due to pathogenic microorganisms between SOT recipients who received pre-emptive treatment and those who did not, but without statistical significance. The mortality rate among SOT recipients with PF-related infection was 35% (95% CI: 21% to 53%). In conclusion, although contamination of the PF of donated organs is frequent, the incidence of PF-related infection is relatively low. A closely clinical and microbiologic monitoring of the SOT recipient in case of culture-positive PF, regardless of the type of microorganism isolated might be do in order to establish a prompt diagnosis of PF-related infection. Copyright © 2017 Elsevier Inc. All rights reserved.

Neural activation during imitation with or without performance feedback: An fMRI study.

PubMed

Zhang, Kaihua; Wang, Hui; Dong, Guangheng; Wang, Mengxing; Zhang, Jilei; Zhang, Hui; Meng, Weixia; Du, Xiaoxia

2016-08-26

In our daily lives, we often receive performance feedback (PF) during imitative learning, and we adjust our behaviors accordingly to improve performance. However, little is known regarding the neural mechanisms underlying this learning process. We hypothesized that appropriate PF would enhance neural activation or recruit additional brain areas during subsequent action imitation. Pictures of 20 different finger gestures without any social meaning were shown to participants from the first-person perspective. Imitation with or without PF was investigated by functional magnetic resonance imaging in 30 healthy subjects. The PF was given by a real person or by a computer. PF from a real person induced hyperactivation of the parietal lobe (precuneus and cuneus), cingulate cortex (posterior and anterior), temporal lobe (superior and transverse temporal gyri), and cerebellum (posterior and anterior lobes) during subsequent imitation. The positive PF and negative PF from a real person, induced the activation of more brain areas during the following imitation. The hyperactivation of the cerebellum, posterior cingulate cortex, precuneus, and cuneus suggests that the subjects exhibited enhanced motor control and visual attention during imitation after PF. Additionally, random PF from a computer had a small effect on the next imitation. We suggest that positive and accurate PF may be helpful for imitation learning. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Magnetic nanoparticles and thermally responsive polymer for targeted hyperthermia and sustained anti-cancer drug delivery.

PubMed

Wang, Sarah Y; Liu, Michelle C; Kang, Kyung A

2013-01-01

A novel cancer treatment method is being designed using a combination of iron oxide (Fe(3)O(4)) nanoparticles (IONPs) and Pluronic F-127 (PF127). IONPs have been used for heating tumors via an alternating electromagnetic (AEM) field. PF127 is a polymer possessing thermo-reversible and concentration-dependent gelation properties in aqueous solutions. PF127, as a gel, is an attractive drug delivery vehicle due to its zero-order drug release property. The combination of IONPs and PF127 would allow both short-term, tumor-specific, hyperthermic treatment, and long-term sustained drug delivery. As a preliminary study, the gelling and heating properties of IONPs/PF127 mixtures were investigated: 18% (w/w) PF127 was found to be ideal for our purpose because it gels at 28.0°C, i.e., it would be injectable at room temperature (20-25°C) and forms gel upon injection into the body (37°C). IONPs in PF127 showed little effect on gelation temperatures. The heating performance of IONPs in PF127 slightly, but linearly decreased with PF127. In the IONP concentration range of 0.01-0.05% (w/v) mixed with PF127 at 18% (w/w), the heating performance increased linearly with the increase in IONP concentration.

Comparing Universal Lynch Syndrome Tumor Screening Programs to Evaluate Associations Between Implementation Strategies and Patient Follow-through

PubMed Central

Cragun, Deborah; DeBate, Rita D.; Vadaparampil, Susan T.; Baldwin, Julie; Hampel, Heather; Pal, Tuya

2014-01-01

Purpose Universal tumor screening (UTS) for all colorectal cancer (CRC) patients can improve the identification of Lynch syndrome, the most common cause of hereditary CRC. This multiple-case study explored how variability in UTS procedures influence patient follow-through (PF) with germline testing after a screen-positive result. Methods Data were obtained through web-based surveys and telephone interviews with institutional informants. Institutions were categorized as Low-PF (≤10% underwent germline testing), Medium-PF (11–40%), or High-PF (>40%). To identify implementation procedures (i.e., conditions) unique High-PF institutions, qualitative comparative analysis was performed. Results Twenty-one informants from fifteen institutions completed surveys and/or interviews. Conditions present among all five High-PF institutions included: 1) disclosure of screen-positive results to patients by genetic counselors (GCs); and 2) GCs either facilitate physician referrals to genetics or eliminated the need for referrals. Although both of these High-PF conditions were present among two Medium-PF institutions, automatic reflex testing was lacking and difficulty contacting screen-positive patients was a barrier. The three remaining Medium-PF and five Low-PF institutions lacked High-PF conditions. Conclusion Methods for streamlining UTS procedures, incorporating a high level of involvement of GCs in results tracking and communication, and reducing barriers to patient contact are reviewed within a broader discussion on maximizing the effectiveness and public health impact of UTS. PMID:24651603

Forecasting future needs and optimal allocation of medical residency positions: the Emilia-Romagna Region case study.

PubMed

Senese, Francesca; Tubertini, Paolo; Mazzocchetti, Angelina; Lodi, Andrea; Ruozi, Corrado; Grilli, Roberto

2015-01-30

Italian regional health authorities annually negotiate the number of residency grants to be financed by the National government and the number and mix of supplementary grants to be funded by the regional budget. This study provides regional decision-makers with a requirement model to forecast the future demand of specialists at the regional level. We have developed a system dynamics (SD) model that projects the evolution of the supply of medical specialists and three demand scenarios across the planning horizon (2030). Demand scenarios account for different drivers: demography, service utilization rates (ambulatory care and hospital discharges) and hospital beds. Based on the SD outputs (occupational and training gaps), a mixed integer programming (MIP) model computes potentially effective assignments of medical specialization grants for each year of the projection. To simulate the allocation of grants, we have compared how regional and national grants can be managed in order to reduce future gaps with respect to current training patterns. The allocation of 25 supplementary grants per year does not appear as effective in reducing expected occupational gaps as the re-modulation of all regional training vacancies.

Mg-isotopic fractionation in the manila clam (Ruditapes philippinarum): New insights into Mg incorporation pathway and calcification process of bivalves

NASA Astrophysics Data System (ADS)

Planchon, Frédéric; Poulain, Céline; Langlet, Denis; Paulet, Yves-Marie; André, Luc

2013-11-01

We estimate the magnesium stable isotopic composition (δ26Mg) of the major compartments involved in the biomineralisation process of euryhaline bivalve, the manila clam Ruditapes philippinarum. Our aim is to identify the fractionation processes associated with Mg uptake and its cycling/transport in the bivalve organism, in order to better assess the controlling factors of the Mg isotopic records in bivalve shells. δ26Mg were determined in seawater, in hemolymph, extrapallial fluid (EPF), soft tissues and aragonitic shell of adult clams collected along the Auray River estuary (Gulf of Morbihan, France) at two sites showing contrasted salinity regimes. The large overall δ26Mg variations (4.16‰) demonstrate that significant mass-dependent Mg isotopic fractionations occur during Mg transfer from seawater to the aragonitic shell. Soft tissues span a range of fractionation factors relative to seawater (Δ26Mgsoft tissue-seawater) of 0.42 ± 0.12‰ to 0.76 ± 0.12‰, and show evidence for biological isotopic fractionation of Mg. Hemolymph and EPF are on average isotopically close to seawater (Δ26Mghemolymph-seawater = -0.20 ± 0.27‰; 2 sd; n = 5 and Δ26MgEPF-seawater = -0.23 ± 0.25‰; 2 sd; n = 5) indicating (1) a predominant seawater origin for Mg in the intercellular medium and (2) a relatively passive transfer route through the bivalve organism into the calcifying fluid. The lightest isotopic composition is found in shell, with δ26Mg ranging from -1.89 ± 0.07‰ to -4.22 ± 0.06‰. This range is the largest in the dataset and is proposed to result from a combination of abiotic and biologically-driven fractionation processes. Abiotic control includes fractionation during precipitation of aragonite and accounts for Δ26Mgaragonite-seawater ≈ 1000 ln αaragonite-seawater = -1.13 ± 0.28‰ at 20 °C based on literature data. Deviations from inorganic precipitate (expressed as Δ26MgPhysiol) appear particularly variable in the clam shell, ranging from 0.03‰ to -2.20‰, which indicates that bivalve shell formation can proceed either under fractionation similar to inorganically-precipitated aragonite or under variable physiological influences. These physiological isotopic effects may be consistent with a regulation of dissolved Mg content in hemolymph and/or EPF due to Mg incorporation into soft tissue and/or Mg fixation by organic macromolecules. Using closed- and open-system models we estimate that Δ26MgPhysiol can be satisfactorily resolved with a remaining Mg fraction in hemolymph and/or EPF of 74% down to 2%. However, this feature is not reflected in our hemolymph and EPF data and may indicate that regulation processes and isotopic fractionation may take place in self-contained spaces located close to calcification sites. The potential role of the shell organic matrix, which may host non-lattice-bound Mg in the shell, is also discussed but remains difficult to assess with our data. Regarding the large physiological effects, the δ26Mg record in the Manila clam shell offers limited potential as a proxy of temperature or seawater Mg isotopic composition. In contrast, the sensitivity of its δ26Mg to the salinity regime may offer an interesting tool to track changes in clam biological activity in estuarine environments.

Deciphering the key residues in Plasmodium falciparum beta-ketoacyl acyl carrier protein reductase responsible for interactions with Plasmodium falciparum acyl carrier protein.

PubMed

Karmodiya, Krishanpal; Modak, Rahul; Sahoo, Nirakar; Sajad, Syed; Surolia, Namita

2008-10-01

The type II fatty acid synthase (FAS) pathway of Plasmodium falciparum is a validated unique target for developing novel antimalarials, due to its intrinsic differences from the typeI pathway operating in humans. beta-Ketoacyl acyl carrier protein (ACP) reductase (FabG) performs the NADPH-dependent reduction of beta-ketoacyl-ACP to beta-hydroxyacyl-ACP, the first reductive step in the elongation cycle of fatty acid biosynthesis. In this article, we report intensive studies on the direct interactions of Plasmodium FabG and Plasmodium ACP in solution, in the presence and absence of its cofactor, NADPH, by monitoring the change in intrinsic fluorescence of P.falciparum FabG (PfFabG) and by surface plasmon resonance. To address the issue of the importance of the residues involved in strong, specific and stoichiometric binding of PfFabG to P.falciparum ACP (PfACP), we mutated Arg187, Arg190 and Arg230 of PfFabG. The activities of the mutants were assessed using both an ACP-dependent and an ACP-independent assay. The affinities of all the PfFabG mutants for acetoacetyl-ACP (the physiological substrate) were reduced to different extents as compared to wild-type PfFabG, but were equally active in biochemical assays with the substrate analog acetoacetyl-CoA. Kinetic analysis and studies of direct binding between PfFabG and PfACP confirmed the identification of Arg187 and Arg230 as critical residues for the PfFabG-PfACP interactions. Our studies thus reveal the significance of the positively charged/hydrophobic patch located adjacent to the active site cavities of PfFabG for interactions with PfACP.

Advancing nutritional therapy: A novel polymeric formulation attenuates intestinal inflammation in a murine colitis model and suppresses pro-inflammatory cytokine production in ex-vivo cultured inflamed colonic biopsies.

PubMed

Alhagamhmad, Moftah H; Lemberg, Daniel A; Day, Andrew S; Tan, Li-Zsa; Ooi, Chee Y; Krishnan, Usha; Gupta, Nitin; Munday, John S; Leach, Steven T

2017-04-01

Nutritional therapy is a viable therapeutic option for the treatment of Crohn disease (CD). Therefore improving nutritional therapy would greatly benefit CD patients. The aim of this study was to define the anti-inflammatory properties of a novel nutritional polymeric formula (PF) in comparison to a currently available standard PF. Dextran sodium sulfate (DSS) was utilized to induce colitis in C57BL/6 mice with mice randomized to receive either standard PF or novel PF in addition to control groups. Changes in body weight were recorded and colonic damage was assessed histologically and biochemically. Additional experiments were also included where the cytokine response of colonic biopsies from pediatric CD patients was measured following exposure to standard PF or novel PF. DSS induced significant body weight loss, morphological changes in the colon, increased myeloperoxidase (MPO) activity and up-regulated colonic mRNA expression of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-12 and monocyte chemoattractant protein (MCP)-1, as well as associated histological changes. Other than histological damage, these inflammatory changes were reversed by both novel and standard PF. However, the novel PF, but not standard PF, completely suppressed TNF-α, IL-6 and IL-8 levels from cultured biopsies. Newly developed nutritional formula reproducibly ameliorated DSS-induced colitis in a murine model, although this response was not measurably different to standard PF. However, the novel PF was significantly superior in suppressing inflammatory cytokine release from cultured colonic biopsies. Collectively, these findings support a possible role for novel PF in advancing nutritional therapy for CD patients. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Deep brain stimulation of the center median-parafascicular complex of the thalamus has efficient anti-parkinsonian action associated with widespread cellular responses in the basal ganglia network in a rat model of Parkinson's disease.

PubMed

Jouve, Loréline; Salin, Pascal; Melon, Christophe; Kerkerian-Le Goff, Lydia

2010-07-21

The thalamic centromedian-parafascicular (CM/Pf) complex, mainly represented by Pf in rodents, is proposed as an interesting target for the neurosurgical treatment of movement disorders, including Parkinson's disease. In this study, we examined the functional impact of subchronic high-frequency stimulation (HFS) of Pf in the 6-hydroxydopamine-lesioned hemiparkinsonian rat model. Pf-HFS had significant anti-akinetic action, evidenced by alleviation of limb use asymmetry (cylinder test). Whereas this anti-akinetic action was moderate, Pf-HFS totally reversed lateralized neglect (corridor task), suggesting potent action on sensorimotor integration. At the cellular level, Pf-HFS partially reversed the dopamine denervation-induced increase in striatal preproenkephalin A mRNA levels, a marker of the neurons of the indirect pathway, without interfering with the markers of the direct pathway (preprotachykinin and preprodynorphin). Pf-HFS totally reversed the lesion-induced changes in the gene expression of cytochrome oxidase subunit I in the subthalamic nucleus, the globus pallidus, and the substantia nigra pars reticulata, and partially in the entopeduncular nucleus. Unlike HFS of the subthalamic nucleus, Pf-HFS did not induce per se dyskinesias and directly, although partially, alleviated L-3,4-dihydroxyphenylalanine (L-DOPA)-induced forelimb dyskinesia. Conversely, L-DOPA treatment negatively interfered with the anti-parkinsonian effect of Pf-HFS. Altogether, these data show that Pf-DBS, by recruiting a large basal ganglia circuitry, provides moderate to strong anti-parkinsonian benefits that might, however, be affected by L-DOPA. The widespread behavioral and cellular outcomes of Pf-HFS evidenced here demonstrate that CM/Pf is an important node for modulating the pathophysiological functioning of basal ganglia and related disorders.

Long-term clinical and radiographic outcome of patello-femoral realignment procedures: a minimum of 15-year follow-up.

PubMed

Vivod, Gregor; Verdonk, Peter; Drobnič, Matej

2014-11-01

A retrospective single-centre study was focused on the long-term outcome after different patello-femoral (PF) realignment procedures. Thirty-nine patients treated for recurrent PF instability were examined after a mean post-operative time of 22.5 years. Their 78 knees were divided into: non-operated knees (NON-OPERATED)-N = 24, isolated proximal procedures (PROXIMAL)-N = 22, isolated distal procedures (DISTAL)-N = 10, and combined procedures (COMBINED)-N = 22. PF-related medical history together with clinical, subjective (KOOS and Kujala scores), and radiographic (Caton-Deschamps PF height index, Kellgren-Lawrence scale for tibio-femoral OA, and Iwano classification for PF OA) evaluation was conducted. PF re-dislocation rate was comparable between PROXIMAL (36%), DISTAL (20%), and COMBINED (32%). Isolated proximal procedures revealed less central patella positions (PROXIMAL 64%; DISTAL 90%; COMBINED 95%) and more frequent PF apprehension test (PROXIMAL 82%; DISTAL 40%, COMBINED 50%). KOOS and Kujala scores were similar in all three surgical subgroups, but significantly lower than in NON-OPERATED. Patellas were positioned lower after DISTAL, 0.8 (0.5-1.0) or COMBINED, 0.9 (0.4-1.3). Kellgren-Lawrence scores ≥2 were found in 42% NON-OPERATED, 37% PROXIMAL, 70% DISTAL, and 59% COMBINED, whereas Iwano classification ≥2 was confirmed in 46% NON-OPERATED, 64% PROXIMAL, 80% DISTAL, and 86% COMBINED. High PF re-dislocation rates together with a very high incidence of PF OA indicate that PF realignment strategies used traditionally had failed to reach their long-term expectations. The transfer of tibial tuberosity resulted in more constrained PF joints than isolated proximal procedures which allowed for more residual PF instability. Distal procedures additionally increased the likelihood for tibio-femoral OA. III.

Platelet factor 4/CXCL4 induces phagocytosis and the generation of reactive oxygen metabolites in mononuclear phagocytes independently of Gi protein activation or intracellular calcium transients.

PubMed

Pervushina, Olga; Scheuerer, Barbara; Reiling, Norbert; Behnke, Lars; Schröder, Jens-M; Kasper, Brigitte; Brandt, Ernst; Bulfone-Paus, Silvia; Petersen, Frank

2004-08-01

Platelet factor 4 (PF-4), a platelet-derived CXC chemokine, is known to prevent human monocytes from apoptosis and to promote differentiation of these cells into HLA-DR(-) macrophages. In this study, we investigated the role of PF-4 in the control of acute monocyte proinflammatory responses involved in the direct combat of microbial invaders. We show that PF-4 increases monocyte phagocytosis and provokes a strong formation of oxygen radicals but lacks a chemotactic activity in these cells. Compared with FMLP, PF-4-induced oxidative burst was later in its onset but was remarkably longer in its duration (lasting for up to 60 min). Furthermore, in PF-4-prestimulated cells, FMLP- as well as RANTES-induced burst responses became synergistically enhanced. As we could show, PF-4-mediated oxidative burst in monocytes does not involve Gi proteins, elevation of intracellular free calcium concentrations, or binding to CXCR3B, a novel PF-4 receptor recently discovered on endothelial cells. Moreover, we found that PF-4 acts on macrophages in a dual manner. On the one hand, very similar to GM-CSF or M-CSF, PF-4 treatment of monocytes generates macrophages with a high capacity for unspecific phagocytosis. On the other hand, short term priming of GM-CSF-induced human macrophages with PF-4 substantially increases their capability for particle ingestion and oxidative burst. A comparable effect was also observed in murine bone marrow-derived macrophages, indicating cross-reactivity of human PF-4 between both species. Taken together, PF-4 may play a crucial role in the induction and maintenance of an unspecific immune response.

Physical Activity, Physical Fitness and Leukocyte Telomere Length: the Cardiovascular Health Study.

PubMed Central

Soares-Miranda, Luisa; Imamura, Fumiaki; Siscovick, David; Jenny, Nancy Swords; Fitzpatrick, Annette L; Mozaffarian, Dariush

2015-01-01

Introduction The influence of physical activity (PA) and physical fitness (PF) at older ages on changes in telomere length (TL), repetitive DNA sequences that may mark biologic aging, is not well-established. Few prior studies have been conducted in older adults, these were mainly cross-sectional, and few evaluated PF. Methods We investigated cross-sectional and prospective associations of PA and PF with leukocyte TL among 582 older adults (age 73±5 y at baseline) in the Cardiovascular Health Study, having serial TL measures and PA and PF assessed multiple times. Cross-sectional associations were assessed using multivariable repeated-measures regression, in which cumulatively averaged PA and PF measures were related to TL. Longitudinal analyses assessed cumulatively averaged PA and PF against later changes in TL; and changes in cumulatively averaged PA and PF against changes in TL. Results Cross-sectionally, greater walking distance and chair test performance, but not other PA and PF measures, were each associated with longer TL (p-trend=0.007, 0.04 respectively). In longitudinal analyses, no significant associations of baseline PA and PF with change in TL were observed. In contrast, changes in leisure-time activity and chair test performance were each inversely associated with changes in TL. Conclusions Cross-sectional analyses suggest that greater PA and PF are associated with longer TL. Prospective analyses show that changes in PA and PF are associated with differences in changes in TL. Even later in life, changes in certain PA and PF measures are associated with changes in TL, suggesting that leisure-time activity and fitness could reduce leukocyte telomere attrition among older adults. PMID:26083773

Effect of the shell material and confinement type on the conversion efficiency of core/shell quantum dot nanocrystal solar cells.

PubMed

Sahin, Mehmet

2018-05-23

In this study, the effects of the shell material and confinement type on the conversion efficiency of core/shell quantum dot nanocrystal (QDNC) solar cells have been investigated in detail. For this purpose, the conventional, i.e. original, detailed balance model, developed by Shockley and Queisser to calculate an upper limit for the conversion efficiency of silicon p-n junction solar cells, is modified in a simple and effective way to calculate the conversion efficiency of core/shell QDNC solar cells. Since the existing model relies on the gap energy ([Formula: see text]) of the solar cell, it does not make an estimation about the effect of QDNC materials on the efficiency of the solar cells, and gives the same efficiency values for several QDNC solar cells with the same [Formula: see text]. The proposed modification, however, estimates a conversion efficiency in relation to the material properties and also the confinement type of the QDNCs. The results of the modified model show that, in contrast to the original one, the conversion efficiencies of different QDNC solar cells, even if they have the same [Formula: see text], become different depending upon the confinement type and shell material of the core/shell QDNCs, and this is crucial in the design and fabrication of the new generation solar cells to predict the confinement type and also appropriate QDNC materials for better efficiency.

Bilateral comparison of 10 pF and 100 pF standards (ongoing BIPM key comparisons BIPM.EM-K14.a and 14.b) between the NIS (Egypt) and the BIPM

NASA Astrophysics Data System (ADS)

Gournay, Pierre; Helmy, M.; Raouf, A.; Hamed, Heba A. M.; Eliwa Gad, A.

2017-01-01

This report presents the results of a bilateral comparison of 10 pF and 100 pF capacitance standards between the NIS (Egypt) and the BIPM carried out in 2016. The comparison at 10 pF forms part of the ongoing BIPM key comparison BIPM.EM-K14.a and that at 100 pF of the ongoing BIPM key comparison BIPM.EM-K14.b. The BIPM is the pilot laboratory for both of these comparisons. Two 10 pF and 100 pF travelling standards belonging to the BIPM were used in this comparison carried out with an 'A-B-A' pattern of measurements. The standards were measured first at the BIPM for a period of about one month, then for a similar period at the NIS, and finally again at the BIPM. The measurand was the two terminal-pair capacitance at a frequency of either 1000 Hz or 1592 Hz, for a measuring rms voltage of 15 V at 10 pF and 10 V at 100 pF. One of the 10 pF travelling standards had to be eliminated from the comparison due to a bistable behaviour, possibly due to transportation. The results from the NIS and the BIPM at both 1000 Hz and 1592 Hz were found to be in good agreement, with a difference smaller than the relative expanded uncertainty (95 % confidence, k = 2) of about 0.72 × 10-6 at 10 pF and about 0.65 × 10-6 at 100 pF. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

DPF heater attachment mechanisms

DOEpatents

Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

2011-04-26

An exhaust filter system includes a particulate filter (PF) that is disposed downstream from an engine. The PF filters particulates within an exhaust from the engine. A heating element heats particulate matter in the PF. A fastener limits expansion movement of the heating element relative to the PF.

Physics First: Impact on SAT Math Scores

NASA Astrophysics Data System (ADS)

Bouma, Craig E.

Improving science, technology, engineering, and mathematics (STEM) education has become a national priority and the call to modernize secondary science has been heard. A Physics First (PF) program with the curriculum sequence of physics, chemistry, and biology (PCB) driven by inquiry- and project-based learning offers a viable alternative to the traditional curricular sequence (BCP) and methods of teaching, but requires more empirical evidence. This study determined impact of a PF program (PF-PCB) on math achievement (SAT math scores) after the first two cohorts of students completed the PF-PCB program at Matteo Ricci High School (MRHS) and provided more quantitative data to inform the PF debate and advance secondary science education. Statistical analysis (ANCOVA) determined the influence of covariates and revealed that PF-PCB program had a significant (p < .05) impact on SAT math scores in the second cohort at MRHS. Statistically adjusted, the SAT math means for PF students were 21.4 points higher than their non-PF counterparts when controlling for prior math achievement (HSTP math), socioeconomic status (SES), and ethnicity/race.

Quartetting in even-even and odd-odd N=Z nuclei

NASA Astrophysics Data System (ADS)

Sambataro, M.; Sandulescu, N.

2018-02-01

We report on a microscopic description of even-even N = Z nuclei in a formalism of quartets. Quartets are four-body correlated structures characterized by isospin T and angular momentum J. We show that the ground state correlations induced by a realistic shell model interaction can be well accounted for in terms of a restricted set of T = 0 low-J quartets, the J = 0 one playing by far a leading role among them. A conceptually similar description of odd-odd self-conjugate nuclei is given in terms of two distinct families of building blocks, one formed by the same T = 0 quartets employed for the even-even systems and the other by collective pairs with either T = 0 or T = 1. Some applications of this formalism are discussed for nuclei in the sd shell.

Unique Cardiac Purkinje Fiber Transient Outward Current β-Subunit Composition

PubMed Central

Xiao, Ling; Koopmann, Tamara T.; Ördög, Balázs; Postema, Pieter G.; Verkerk, Arie O.; Iyer, Vivek; Sampson, Kevin J.; Boink, Gerard J.J.; Mamarbachi, Maya A.; Varro, Andras; Jordaens, Luc; Res, Jan; Kass, Robert S.; Wilde, Arthur A.; Bezzina, C.R.; Nattel, Stanley

2015-01-01

Rationale A chromosomal haplotype producing cardiac overexpression of dipeptidyl peptidase-like protein-6 (DPP6) causes familial idiopathic ventricular fibrillation. The molecular basis of transient outward current (Ito) in Purkinje fibers (PFs) is poorly understood. We hypothesized that DPP6 contributes to PF Ito and that its overexpression might specifically alter PF Ito properties and repolarization. Objective To assess the potential role of DPP6 in PF Ito. Methods and Results Clinical data in 5 idiopathic ventricular fibrillation patients suggested arrhythmia origin in the PF-conducting system. PF and ventricular muscle Ito had similar density, but PF Ito differed from ventricular muscle in having tetraethylammonium sensitivity and slower recovery. DPP6 overexpression significantly increased, whereas DPP6 knockdown reduced, Ito density and tetraethylammonium sensitivity in canine PF but not in ventricular muscle cells. The K+-channel interacting β-subunit K+-channel interacting protein type-2, essential for normal expression of Ito in ventricular muscle, was weakly expressed in human PFs, whereas DPP6 and frequenin (neuronal calcium sensor-1) were enriched. Heterologous expression of Kv4.3 in Chinese hamster ovary cells produced small Ito; Ito amplitude was greatly enhanced by coexpression with K+-channel interacting protein type-2 or DPP6. Coexpression of DPP6 with Kv4.3 and K+-channel interacting protein type-2 failed to alter Ito compared with Kv4.3/K+-channel interacting protein type-2 alone, but DPP6 expression with Kv4.3 and neuronal calcium sensor-1 (to mimic PF Ito composition) greatly enhanced Ito compared with Kv4.3/neuronal calcium sensor-1 and recapitulated characteristic PF kinetic/pharmacological properties. A mathematical model of cardiac PF action potentials showed that Ito enhancement can greatly accelerate PF repolarization. Conclusions These results point to a previously unknown central role of DPP6 in PF Ito, with DPP6 gain of function selectively enhancing PF current, and suggest that a DPP6-mediated PF early-repolarization syndrome might be a novel molecular paradigm for some forms of idiopathic ventricular fibrillation. PMID:23532596

The Characterization of Obese Polycystic Ovary Syndrome Rat Model Suitable for Exercise Intervention

PubMed Central

Qiu, Shuwei; Jiang, Zhongli

2014-01-01

Objective To develop a new polycystic ovary syndrome (PCOS) rat model suitable for exercise intervention. Method Thirty six rats were randomly divided into three experimental groups: PCOS rats with high-fat diet (PF, n = 24), PCOS rats with ordinary diet (PO, n = 6), and control rats with ordinary diet (CO, n = 6). Two kinds of PCOS rat model were made by adjustment diet structure and testosterone injection for 28 days. After a successful animal model, PF model rats were randomly assigned to three groups: exercise with a continuation of high-fat diet (PF-EF, n = 6), sedentary with a continuation of high-fat diet (PF-SF, n = 6), exercise with an ordinary diet (PF-EO, n = 6). Fasting blood glucose (FBG) and insulin (FINS), estrogen (E2), progesterone (P), and testosterone (T) in serum were determined by RIA, and ovarian morphology was evaluated by Image-Pro plus 6.0. Results Body weight, Lee index, FINS increased significantly in PF rat model. Serum levels of E2 and T were significantly higher in PF and PO than in CO. Ovary organ index and ovarian areas were significant lower in PF than in CO. After intervention for 2 weeks, the levels of 1 h postprandial blood glucose (PBG1), 2 h postprandial blood glucose (PBG2), FINS and the serum levels of T decreased significantly in PF-EF rats and PF-EO rats. The ratio of FBG/FINS was significant higher in PF-EO rats than in PF-SF rats. Ovarian morphology showed that the numbers of preantral follicles and atretic follicles decreased significantly, and the numbers of antral follicles and corpora lutea increased significantly in the rats of PF-EF and PF-EO. Conclusion By combination of high-fat diet and testosterone injection, the obese PCOS rat model is conformable with the lifestyle habits of fatty foods and insufficient exercise, and has metabolic and reproductive characteristics of human PCOS. This model can be applied to study exercise intervention. PMID:24905232

Blockade of mGluR5 in the nucleus accumbens shell but not core attenuates heroin seeking behavior in rats

PubMed Central

Lou, Zhong-ze; Chen, Ling-hong; Liu, Hui-feng; Ruan, Lie-min; Zhou, Wen-hua

2014-01-01

Aim: Glutamatergic neurotransmission in the nucleus accumbens (NAc) is crucial for the relapse to heroin seeking. The aim of this study was to determine whether mGluR5 in the NAc core or shell involved in heroin seeking behavior in rats. Methods: Male SD rats were self-administered heroin under a fixed-ratio 1 (FR1) reinforcement schedule for 14 d, and subsequently withdrawn for 2 weeks. The selective mGluR5 antagonist 2-methyl-6-phenylethynyl-pyridine (MPEP, 5, 15 and 50 nmol per side) was then microinjected into the NAc core or shell 10 min before a heroin-seeking test induced by context, cues or heroin priming. Results: Microinjection of MPEP into the NAc shell dose-dependently decreased the heroin seeking induced by context, cues or heroin priming. In contrast, microinjection of MPEP into the NAc core did not alter the heroin seeking induced by cues or heroin priming. In addition, microinjection with MPEP (15 nmol per side) in the NAc shell reversed both the percentage of open arms entries (OE%) and the percentage of time spent in open arms (OT%) after heroin withdrawal. Microinjection of MPEP (50 nmol per side) in the striatum as a control location did not affect the heroin seeking behavior. Microinjection of MPEP in the 3 locations did not change the locomotion activities. Conclusion: Blockade of mGluR5 in NAc shell in rats specifically suppresses the relapse to heroin-seeking and anxiety-like behavior, suggesting that mGluR5 antagonists may be a potential candidate for the therapy of heroin addiction. PMID:25399651

Low levels of circulating platelet factor 4 (PF4, CXCL4) in subclinically hypothyroid autoimmune thyroiditis.

PubMed

Görar, S; Ademoğlu, E; Çarlıoğlu, A; Alioğlu, B; Bekdemir, H; Sağlam, B; Candan, Z; Üçler, R; Culha, C; Aral, Y

2016-02-01

Chemokines play an important role in the pathogenesis of autoimmune thyroid diseases. Platelet factor 4 (PF4, CXCL4) released from activated platelets is a chemokine. However, its clinical importance in autoimmune thyroiditis remains unknown. This study is intended to determine circulating levels of PF4 levels in patients with autoimmune thyroiditis (AIT). Circulating levels of PF4 were measured in 34 consecutive patients with newly diagnosed AIT and 18 euthyroid controls. Among AIT group, 16 patients were euthyroid and 18 had subclinic hypothyroidism. Controls and individuals with AIT were similar in terms of age. Serum levels of PF4 were comparable in patients with AIT and in controls. Among patients with AIT, PF4 was significantly lower in those with subclinical hypothyroidism than in euthyroid individuals (p = 0.001). In correlation analysis, PF4 was negatively correlated with TSH (r = -0.663, p = 0.000) and positively correlated with free T4 (r = 0.428, p = 0.012). There was not any significant correlation between PF4 and AbTPO, AbTg. The present study demonstrated for the first time that circulating PF4 levels are decreased in subclinically hypothyroid AIT. This result draws attention to the circulating PF4 levels in subclinically hypothyroid AIT and may shed light on further researches at this topic.

The Clp Chaperones and Proteases of the Human Malaria Parasite Plasmodium falciparum

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

M El Bakkouri; A Pow; A Mulichak

The Clpchaperones and proteases play an important role in protein homeostasis in the cell. They are highly conserved across prokaryotes and found also in the mitochondria of eukaryotes and the chloroplasts of plants. They function mainly in the disaggregation, unfolding and degradation of native as well as misfolded proteins. Here, we provide a comprehensive analysis of the Clpchaperones and proteases in the humanmalariaparasitePlasmodiumfalciparum. The parasite contains four Clp ATPases, which we term PfClpB1, PfClpB2, PfClpC and PfClpM. One PfClpP, the proteolytic subunit, and one PfClpR, which is an inactive version of the protease, were also identified. Expression of all Clpchaperonesmore » and proteases was confirmed in blood-stage parasites. The proteins were localized to the apicoplast, a non-photosynthetic organelle that accommodates several important metabolic pathways in P. falciparum, with the exception of PfClpB2 (also known as Hsp101), which was found in the parasitophorous vacuole. Both PfClpP and PfClpR form mostly homoheptameric rings as observed by size-exclusion chromatography, analytical ultracentrifugation and electron microscopy. The X-ray structure of PfClpP showed the protein as a compacted tetradecamer similar to that observed for Streptococcus pneumoniae and Mycobacterium tuberculosis ClpPs. Our data suggest the presence of a ClpCRP complex in the apicoplast of P. falciparum.« less

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

Park, Jeong Su; Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752; Kang, Dong Hoon

p70 ribosomal S6 kinase 1 (S6K1) is an important serine/threonine kinase and downstream target of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway. PF-4708671 is a specific inhibitor of S6K1, and prevents S6K1-mediated phosphorylation of the S6 protein. PF-4708671 treatment often leads to apoptotic cell death. However, the protective mechanism against PF-4708671-induced cell death has not been elucidated. The nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway is essential for protecting cells against oxidative stress. p62, an adaptor protein in the autophagic process, enhances Nrf2 activation through the impairment of Keap1 activity. In thismore » study, we showed that PF-4708671 induces autophagic Keap1 degradation-mediated Nrf2 activation in p62-dependent manner. Furthermore, p62-dependent Nrf2 activation plays a crucial role in protecting cells from PF-4708671-mediated apoptosis. - Highlights: • PF-4708671, a S6K1-specific inhibitor, prevents S6K1-mediated S6 phosphorylation. • However, PF-4708671 treatment often leads to apoptotic cell death. • Protective mechanism against PF-4708671-induced cell death remains to be elucidated. • PF-4708671 induced p62-dependent, autophagic Keap1 degradation-mediated Nrf2 activation. • p62-dependent Nrf2 activation protects cells from PF-4708671-mediated apoptosis.« less

Determination of PF-04928473 in human plasma using liquid chromatography with tandem mass spectrometry

PubMed Central

Jain, Lokesh; Gardner, Erin R.; Venitz, Jürgen; Giaccone, Giuseppe; Houk, Brett E.; Figg, William D.

2010-01-01

A simple, rapid and sensitive liquid chromatography/tandem mass spectrometric (LC/MS/MS) analytical method was developed for quantification of Hsp90 inhibitor PF-04928473 in human plasma, following administration of its prodrug, PF-04929113. Sample processing involved protein precipitation by addition of 0.4 mL of methanol containing internal standard (PF-04972487) to 50 μL volume of plasma sample. Chromatographic separation of PF-04928473 and PF-04972487 was achieved on a Phenomenex® Luna C18(2) (2.0×50 mm, 5 μm) column using a gradient elution method with mobile phase solvents: methanol containing 0.1% formic acid and 0.1% formic acid at a flow rate of 0.25 mL/min. Detection was performed in electrospray positive ionization mode, monitoring the ion transitions from m/z 465.1→350.1 (PF-04928473) and m/z 447.0→329.1 (PF-04972487). The retention times for PF-04928473 and PF-04972487 were 1.86 and 2.85 minutes, respectively. Calibration curves were generated in the range of 2–2000 ng/mL. The accuracy and precision ranged from 94.1–99.0% and 86.7–97.6%, respectively, which were calculated using quality control samples of three different concentrations analyzed in quintuplicate on four different days. PMID:20951100

Examining ruthenium chromophores for the photochemical reduction of CO2 to methanol

NASA Astrophysics Data System (ADS)

Boston, David J.

Our consumption of energy for transportation and electricity has been growing as quickly as our population. As this demand for energy increases we increase our production of carbon dioxide by the burning of fossil fuels to try and meet this increasing demand. A sustainable method to convert carbon dioxide (CO2) to a viable liquid fuel is one potential way in which both the increasing energy demand and increasing CO2 concentration issues can both be helped. Currently such methods being investigated include thermal, electrochemical, and photochemical processes. Because thermal conversion is not an ideal situation because of the requirement of strong reducing agents or extreme conditions such as steam reformation reactions, we need to find better alternatives such as electrochemical and photochemical methods. Both electrochemical and photochemical methods have the ability to be sustainable, however, the vast majority of these systems are limited to producing CO and/or formic acid, with only a few performing deeper reduction to products such formaldehyde, methanol and methane. All of the systems capable of reducing CO2 past two electrons involve either a heterogeneous catalyst (e.g. TiO2) or an electrode. In recent times Bocarsly and coworkers have shown that pyridine was capable of reducing CO2 to methanol through a sequential process of proton and electron transfers. This process seems to start with the formation of a CO2-pyridine adduct in solution that is reduced one more time to form formate/formic acid. The next reduction is a slow process and allows for a buildup of formate in solution leading to a higher formate concentration in solution. The subsequent reductions seem to occur very rapidly and form methanol at good efficiencies. Theoretical work done recently has argued for the necessity of the Pt, Pd, or GaP surface in the electrochemistry. Carter and coworkers have claimed that the surface of the electrode is a necessary part of the catalysis with the pyridinium being only a cocatalyst for the reduction of CO2. However, Musgrave and coworkers predict that the homogeneous reductions can take place with the aid of water molecules in solution. They allow for a PCET process to take place between the CO 2 and the pyridinium radical. This would allow for a second pathway for the catalytic reduction of CO2 to methanol. Work done during this dissertation has shown that the photochemical reduction of carbon dioxide to methanol is possible using pyridine in a similar manner to Bocarsly and coworkers in their electrochemical system. By replacing the electrode with Ru(phen)3Cl2 it is still possible to drive the reaction using excited states of the chromophore to provide the electrons with enough energy to reduce the pyridinium to the radical species. This system has been shown to produce up to 66 BM methanol after 6 hours of irradiation of 470 nm light. Production of formate is also observed, with ~27 mM being observed within the first hour of irradiation. This system was further investigated with the incorporation of the pyridine catalyst into a chromophore system using the complex [Ru(phen)2dppz](PF 6)2, [Ru(phen)2pbtpalpha](PF6) 2, and [Ru(phen)2pbtpbeta](PF6)2. Cyclic voltammetry experiments for these complexes show similar reduction potentials for with ~100 mV difference between them with [Ru(phen)2dppz](PF 6)2 being the most negative and [Ru(phen)2pbtpbeta](PF 6)2 being the most positive. When the electrolyte solution was saturated with CO2 only [Ru(phen)2pbtpalpha](PF 6)2 and [Ru(phen)2pbtpbeta](PF6) 2 showed a response signifying catalysis was taking place. Initial photochemical tests with these complexes showed that [Ru(phen)2pbtpalpha](PF 6)2 seemed to undergo dimer formation in the absence of CO 2 with [Ru(phen)2pbtpbeta](PF6)2 forming a singly reduced species that is oxidized upon introduction of additional CO2. Electrolysis of [Ru(phen)2pbtpbeta](PF6 )2 produces ~900 BM methanol with both CO and formate being produced as well. Photolysis of [Ru(phen)2pbtpbeta](PF6 )2 in DMF with 1 M H2O and 0.1M TEA, no CO formation observed, however, both methanol and formic acid were observed after 1 hours of irradiation with methanol reaching 45 BM, 285 microM formaldehyde and 650 microM formate.

The mechanical and thermal characteristics of phenolic foam reinforced with kaolin powder and glass fiber fabric

NASA Astrophysics Data System (ADS)

Xiao, Wenya; Huang, Zhixiong; Ding, Jie

2017-12-01

In this work, kaolin powder and glass fiber fabric were added to PF in order to improve its thermal stability and mechanical property. Micro-structures of carbonized PF with kaolin powder were inspected by scanning electron microscopy (SEM) to demonstrate the filler’s pinning effect. SEM results illustrated modified PF had well morphology after high-temperature heat treatment. The Fourier transform infrared spectrometer (FTIR) test was carried out and found that kaolin powder only physically dispersed in PF. The compression test and thermal weight loss test were done on two groups of modified PF (Group A: add powder and fabric; Group B: add powder only). Results showed that all modified PF were better than pure PF, while foams with powder and fabric showed better mechanical characteristic and thermal stability compared with foams with powder only.

Holocene geoarchaeology of the Sixteen Mile Beach barrier dunes in the Western Cape, South Africa

NASA Astrophysics Data System (ADS)

Compton, John S.; Franceschini, Giuliana

2005-01-01

Holocene evolution and human occupation of the Sixteen Mile Beach barrier dunes on the southwest coast of South Africa between Yzerfontein and Saldanha Bay are inferred from the radiocarbon ages of calcareous dune sand, limpet shell ( Patella spp.) manuports and gull-dropped white mussel shells ( Donax serra). A series of coast-parallel dunes have prograded seaward in response to an overall marine regression since the mid-Holocene with dated shell from relict foredunes indicating periods of shoreline progradation that correspond to drops in sea level at around 5900, 4500 and 2400 calibrated years before the present (cal yr B.P.). However, the active foredune, extensively covered by a layer of gull-dropped shell, has migrated 500 m inland by the recycling of eroded dune sand in response to an approximate 1 m sea level rise over the last 700 yr. Manuported limpet shells from relict blowouts on landward vegetated dunes indicate human occupation of coastal dune sites at 6200 and 6000 cal yr B.P. and help to fill the mid-Holocene gap in the regional archaeological record. Coastal midden shells associated with small hearth sites exposed in blowouts on the active foredune are contemporaneous (1600-500 cal yr B.P.) with large midden sites on the western margin of Langebaan Lagoon and suggest an increase in marine resource utilisation associated with the arrival of pastoralism in the Western Cape.

Beneficial influence of topical extra virgin olive oil application on an experimental model of penile fracture in rats.

PubMed

Gunes, Mustafa; Ozkol, Halil; Pirincci, Necip; Gecit, Ilhan; Bilici, Salim; Yildirim, Serkan

2015-08-01

Penile fracture (PF) is known as a traumatic rupture of the tunica albuginea of corpus cavernosum. In this study, we aimed to investigate the healing influence of topical extra virgin olive oil (EVOO) on PF through evaluating levels of some oxidative stress biomarkers for the first time. Histopathological evaluation was also realized. A total of 18 male Sprague-Dawley albino rats were divided into three groups of six rats each as control group, in PF (alone) group, and PF + EVOO group. Experimental PF was formed via incising from the proximal dorsal side of the penis in the rats of all groups except control. While in PF (alone) group, fracture was formed and the incision was primarily closed, in PF + EVOO group in addition to foregoing processes, EVOO was also administrated topically twice a day for 3 weeks. At the end of the experiment, all rats were killed and penectomy was carried out. While malondialdehyde, myeloperoxidase, lipid hyroperoxide, and total oxidant status significantly (p < 0.05) increased, reduced glutathione and total free sulfhydryl groups markedly (p < 0.05) decreased in PF (alone) group when compared with PF + EVOO group. Levels of these parameters were reversed to nearly normal values by topical EVOO application. Protection by EVOO is further substantiated via the improved histological findings in PF + EVOO group as against degenerative changes in the rats of PF (alone) group. Our data revealed that EVOO has protective effect in penile cavernosal tissue through probably its antioxidant, free radical defusing, anti-inflammatory, and antimicrobial effects. © The Author(s) 2013.

Pleural effusion levels of DJ-1 are increased in elderly lung cancer patients with malignant pleural effusions.

PubMed

Vavougios, George; Kerenidi, Theodora; Tsilioni, Irene; Zarogiannis, Sotirios G; Gourgoulianis, Konstantinos I

2015-01-01

DJ-1 is a multifunctional protein implicated in redox dependent cell fate decisions. The aim of our study was to determine the pleural fluid (PF) levels of DJ-1 in malignant pleural effusions (MPEs) secondary to lung cancer. Additionally, we opted to assess potential correlations of DJ-1 PF levels with the PF levels of superoxide dismutase-1 (SOD1) and 8-isoprostane that are known antioxidant enzymes and have been previously reported in MPEs. Forty lung cancer patients with cytological proof of MPE were enrolled in this study. The PF levels of DJ-1, SOD1, and 8-isoprostane were measured by means of enzyme-linked immunosorbent assay. The median PF levels of DJ-1 were 826 ng/mL (interquartile range, IQR: 482-1010 ng/mL). DJ-1 PF levels significantly correlated with PF Cu/Zn-SOD1 and PF 8-isoprostane levels (Spearman's rho, r; r = -0.476, P = 0.002 and r = -0.264, P = 0.033, respectively), PF lactate dehydrogenase (r = -0.497, P = 0.001) and total PF cell counts (r = -0.325, P = 0.041). Finally, in patients aged over 65 the PF DJ-1 levels were significantly higher than patients aged less than 65 (875 ng/mL vs. 607 ng/mL, respectively, P = 0.037). To our knowledge, this is the first report to determine DJ-1's levels in MPEs due to lung cancer. The negative correlations between DJ-1, SOD1, and 8-isorpostane warrant further investigation regarding the altered redox regulation associated with MPEs.

Metal Sulfide Nanocrystals inside Ferritin with Photovoltaic Applications

NASA Astrophysics Data System (ADS)

Hansen, Kameron; Peterson, J. Ryan; Olsen, Cameron; Hogg, Heather; Colton, John; Watt, Richard; Colton Team

Ferritin is a spherical protein shell used universally by organisms to store iron. Due to a number of ferritin's properties (a conductive shell, ability to be arranged in ordered arrays, and high stability), recent theoretical work has proposed that non-native semiconductor nanocrystals inside ferritin can be used for high-efficiency solar energy conversion. We present research on the synthesis of a variety of these nanocrystals (PbS, CuS, Mo2S, ZnS, and PbSe) inside ferritin's hollow interior and band gap energies of the resulting ferritin-nanocrystal constructs. We also report preliminary solar cell results for dye sensitized solar cells with PbS-ferritin as the dye.

Raman spectroscopy and time-resolved photoluminescence of BN and BxCyNz nanotubes

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

Wu, J.; Han, Wei-Qiang; Walukiewicz, W.

2004-01-21

We report Raman and time-resolved photoluminescence spectroscopic studies of multiwalled BN and B{sub x}C{sub y}N{sub z} nanotubes. The Raman spectroscopy shows that the as-grown B{sub x}C{sub y}N{sub z} charge recombination, respectively. Comparison of the photoluminescence of BN nanotubes to that decay process is characterized by two time constants that are attributed to intra- and inter-BN sheet nanotubes as predicted by theory. nanotubes are radially phase separated into BN shells and carbon shells. The photoluminescence of hexagonal BN is consistent with the existence of a spatially indirect band gap in multi-walled BN.

The effect of temperature and dot size on the spectral properties of colloidal InP/ZnS core-shell quantum dots.

PubMed

Narayanaswamy, Arun; Feiner, L F; Meijerink, A; van der Zaag, P J

2009-09-22

Visual color changes between 300 and 510 K were observed in the photoluminescence (PL) of colloidal InP/ZnS core-shell nanocrystals. A subsequent study of PL spectra in the range 2-510 K and fitting the temperature dependent line shift and line width to theoretical models show that the dominant (dephasing) interaction is due to scattering by acoustic phonons of about 23 meV. Low temperature photoluminescence excitation measurements show that the excitonic band gap depends approximately inversely linearly on the quantum dot size d, which is distinctly weaker than the dependence predicted by current theories.

Development of whole sporozoite malaria vaccines.

PubMed

Hollingdale, Michael R; Sedegah, Martha

2017-01-01

Despite recent advances, malaria remains a major health threat both to populations in endemic areas as well travelers, including military personnel, to these areas. Subunit vaccines have not yet achieved sufficient efficacy needed for use in any of these at risk populations. Areas covered: This review discusses the current status of various whole sporozoite vaccine approaches and is mainly focused on current clinical trials. Expert commentary: Nearly 100% efficacy was achieved by administering multiple bites of radiation-attenuated sporozoite (RAS) Plasmodium falciparum-infected mosquitoes; this is impractical for widespread use. Now, this high level efficacy has been reproduced using purified, metabolically active RAS (PfSPZ Sanaria® Vaccine), which is undergoing extensive clinical testing. Alternative whole sporozoite vaccines include immunization with fully infectious sporozoites under chloroquine prophylaxis (CPS) or as genetically-attenuated parasites (GAP). By also manufacturing purified infectious sporozoites, it is now possible to combine these with CPS and GAP, as well as perform challenge studies using controlled doses of sporozoites.

First Direct Mass Measurements of Nuclides around Z =100 with a Multireflection Time-of-Flight Mass Spectrograph

NASA Astrophysics Data System (ADS)

Ito, Y.; Schury, P.; Wada, M.; Arai, F.; Haba, H.; Hirayama, Y.; Ishizawa, S.; Kaji, D.; Kimura, S.; Koura, H.; MacCormick, M.; Miyatake, H.; Moon, J. Y.; Morimoto, K.; Morita, K.; Mukai, M.; Murray, I.; Niwase, T.; Okada, K.; Ozawa, A.; Rosenbusch, M.; Takamine, A.; Tanaka, T.; Watanabe, Y. X.; Wollnik, H.; Yamaki, S.

2018-04-01

The masses of 246Es, 251Fm, and the transfermium nuclei Md-252249 and 254No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N =152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of 246Es and 249,250,252Md were measured for the first time. Using the masses of Md,250249 as anchor points for α decay chains, the masses of heavier nuclei, up to 261Bh and 266Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter δ2 n derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N =152 neutron shell closure for Md and Lr.

rPM6 parameters for phosphorous and sulphur-containing open-shell molecules

NASA Astrophysics Data System (ADS)

Saito, Toru; Takano, Yu

2018-03-01

In this article, we have introduced a reparameterisation of PM6 (rPM6) for phosphorus and sulphur to achieve a better description of open-shell species containing the two elements. Two sets of the parameters have been optimised separately using our training sets. The performance of the spin-unrestricted rPM6 (UrPM6) method with the optimised parameters is evaluated against 14 radical species, which contain either phosphorus or sulphur atom, comparing with the original UPM6 and the spin-unrestricted density functional theory (UDFT) methods. The standard UPM6 calculations fail to describe the adiabatic singlet-triplet energy gaps correctly, and may cause significant structural mismatches with UDFT-optimised geometries. Leaving aside three difficult cases, tests on 11 open-shell molecules strongly indicate the superior performance of UrPM6, which provides much better agreement with the results of UDFT methods for geometric and electronic properties.

Structure analysis for hole-nuclei close to 132Sn by a large-scale shell-model calculation

NASA Astrophysics Data System (ADS)

Wang, Han-Kui; Sun, Yang; Jin, Hua; Kaneko, Kazunari; Tazaki, Shigeru

2013-11-01

The structure of neutron-rich nuclei with a few holes in respect of the doubly magic nucleus 132Sn is investigated by means of large-scale shell-model calculations. For a considerably large model space, including orbitals allowing both neutron and proton core excitations, an effective interaction for the extended pairing-plus-quadrupole model with monopole corrections is tested through detailed comparison between the calculation and experimental data. By using the experimental energy of the core-excited 21/2+ level in 131In as a benchmark, monopole corrections are determined that describe the size of the neutron N=82 shell gap. The level spectra, up to 5 MeV of excitation in 131In, 131Sn, 130In, 130Cd, and 130Sn, are well described and clearly explained by couplings of single-hole orbitals and by core excitations.

Low Cost CaTiO3 Perovskite Synthesized from Scallop (Anadara granosa) Shell as Antibacterial Ceramic Material

NASA Astrophysics Data System (ADS)

Fatimah, Is; Nur Ilahi, Rico; Pratami, Rismayanti

2018-01-01

Research on perovskite CaTiO3 synthesis from scallop (Anadara granosa) shell and its test as material for antibacterial ceramic application have been conducted. The synthesis was performed by calcium extraction from the scallop shell followed by solid-solid reaction of obtained calcium with TiO2. Physicochemical character of the perovskite wasstudied by measurement of crystallinity using x-ray diffraction (XRD), diffuse-reflectance UV Visible spectrophotometry, scanning electrone microscope-energy dispersive x-ray (SEM-EDX) and Fourier-Transform InfraRed. Considering the future application of the perovskite as antibacterial agent, laboratory test of the peroskite as material in antibacterial ceramic preparation was also conducted. Result of research indicated that perovskite formation was obtained and the material demonstrated photocatalytic activity as identified by band gap energy (Eg) value. The significant activity was also reflected by the antibacterial action of formed ceramic.

The students' viewpoint on the quality gap in educational services.

PubMed

Rahim Khanli, Marziyeh; Daneshmandi, Hadi; Choobineh, Alireza

2014-07-01

Students and university community are social and human resources of the country. The students' viewpoints about the quality of educational services can be considered as a basis for planning quality promotion and improving organizational performance. This study was conducted to determine the quality gap in educational services by the students of Health and Nutrition School of Shiraz University of Medical Sciences. In this cross-sectional study, 140 students participated voluntarily (age range=19 to 40 years). The service quality (SERVQUAL) questionnaire was used for data collection. This questionnaire measured the quality gap in 5 dimensions of educational service including assurance, responsiveness, empathy, reliability, and tangibility. The students' perception about the current conditions and their expectations as to optimal conditions can be determined, using this questionnaire. The score of the gap in quality of educational services is calculated from difference between perception and expectation scores. Due to non-normality of data, non-parametric tests were used. To this end, data were analyzed by statistical tests including Wilcoxon, Friedman, Kruskal-Wallis and Mann-Whiteny tests in SPSS 14. The results showed that there was quality gap in all 5 dimensions of educational services. The largest and the smallest gaps were observed in "responsiveness" with a mean±SD of -0.94±0.74 and in "reliability" with a mean±SD of -0.76±0.69, respectively. There was a significant difference in quality gap between the 5 dimensions (p<0.001). According to the results, the students' expectations were higher than their perceptions of current conditions; also, in all aspects of the services their expectations were not met. It is recommended that workshops on customer services, communication skills and personnel's technical skills development should be planned and held. Also, allocating more resources for improving educational facilities and physical environment is recommended.

Electrically heated particulate filter regeneration using hydrocarbon adsorbents

DOEpatents

Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

2011-02-01

An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material selectively heats exhaust passing through the upstream end to initiate combustion of particulates within the PF. A hydrocarbon adsorbent coating applied to the PF releases hydrocarbons into the exhaust to increase a temperature of the combustion of the particulates within the PF.

Application of thermogravimetric studies for optimization of lithium hexafluorophosphate production

NASA Astrophysics Data System (ADS)

Smagin, A. A.; Matyukha, V. A.; Korobtsev, V. P.

Lithium hexafluorophosphate, isolated from hydrogen fluoride solution (anhydrous) by decanting and filtering, is an adduct of composition LiPF 6*HF. By thermogravimetric investigations the dynamics of HF removal from LiPF 6 by LiPF 6*HF thermal decomposition was studied. Based on the experimental data the constants entering into the equations as C = C0*exp( t*K0* exp(- E/RT)) were calculated, explaining the thermal decomposition processes of LiPF 6*HF and LiPF 6.

Shoulder joint abduction motion test bench: a new shoulder test bench for in vitro experiments with active muscle force simulation.

PubMed

Onder, Ursula; Blauth, Michael; Kralinger, Franz; Schmoelz, Werner

2012-05-30

In our society the average age is increasing, as are the number of proximal humeral head fractures. For fixation of these fractures, an increasing number of implants are available. New fixation devices should be compared biomechanically with established methods in a standardized fashion. The test bench that was designed was intended to simulate abduction motion of the humerus actively induced by muscle forces. We used three pneumatic muscles to apply forces to the tendons of the musculus supraspinatus and the bifid musculus deltoideus. Thus, it was possible to create an active abduction in the scapular plane. Two different fracture models (with and without medial support) were stabilised with an angular stable plate in sawbone models to reproduce a known clinical outcome with the newly designed test setup. The resultant force acting on the proximal humerus reached approximately 47% BW (per cent body weight), which amounted to 329.0 N (SD: 21.76). The supraspinatus reached maximum forces of 254.7 N (SD: 20.1) and the deltoid muscle 258.9 N (SD: 16.5). Fracture gap instrumentation with medial support resulted in a significantly reduced per-cycle fracture gap motion. The performance evaluation showed that the simulator produced predicable, reproducible movements with physiological muscle force magnitudes.

Study of soft X-ray emission during wire array implosion under plasma focus conditions at the PF-3 facility

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

Dan’ko, S. A.; Mitrofanov, K. N., E-mail: mitrofan@triniti.ru; Krauz, V. I.

2015-11-15

Results of measurements of soft X-ray emission with photon energies of <1 keV under conditions of a plasma focus (PF) experiment are presented. The experiments were carried out at the world’s largest PF device—the PF-3 Filippov-type facility (I ⩽ 3 MA, T/4 ≈ 15–20 µs, W{sub 0} ⩽ 3 MJ). X-ray emission from both a discharge in pure neon and with a tungsten wire array placed on the axis of the discharge chamber was detected. The wire array imploded under the action of the electric current intercepted from the plasma current sheath of the PF discharge in neon. The measuredmore » soft X-ray powers from a conventional PF discharge in gas and a PF discharge in the presence of a wire array were compared for the first time.« less

The 16PF Tradition in Contemporary Personality Assessment.

ERIC Educational Resources Information Center

Krug, Samuel E.

The 16 Personality Factor Questionnaire (16PF), which is reviewed historically in this essay, represents a unique and significant chapter in the history of personality assessment. During the first 20 years of its existence, the 16PF underwent numerous revisions and restandardizations. During that period, R. B. Cattell, the creator of the 16PF,…

A sugar phosphatase regulates the methylerythritol phosphate (MEP) pathway in malaria parasites

PubMed Central

Edwards, Rachel L.; Kelly, Megan L.; Hodge, Dana M.; Tolia, Niraj H.; Odom, Audrey R.

2014-01-01

Isoprenoid biosynthesis through the methylerythritol phosphate (MEP) pathway generates commercially important products and is a target for antimicrobial drug development. MEP pathway regulation is poorly understood in microorganisms. We employ a forward genetics approach to understand MEP pathway regulation in the malaria parasite, Plasmodium falciparum. The antimalarial fosmidomycin inhibits the MEP pathway enzyme deoxyxylulose 5-phosphate reductoisomerase (DXR). Fosmidomycin-resistant P. falciparum are enriched for changes in the PF3D7_1033400 locus (hereafter referred to as PfHAD1), encoding a homologue of haloacid dehalogenase (HAD)-like sugar phosphatases. We describe the structural basis for loss-of-function PfHAD1 alleles and find that PfHAD1 dephosphorylates a variety of sugar phosphates, including glycolytic intermediates. Loss of PfHAD1 is required for fosmidomycin resistance. Parasites lacking PfHAD1 have increased MEP pathway metabolites, particularly the DXR substrate, deoxyxylulose 5-phosphate. PfHAD1 therefore controls substrate availability to the MEP pathway. Because PfHAD1 has homologs in plants and bacteria, other HAD proteins may be MEP pathway regulators. PMID:25058848

Plasmodium falciparum erythrocyte membrane protein-1 specifically suppresses early production of host interferon-gamma.

PubMed

D'Ombrain, Marthe C; Voss, Till S; Maier, Alexander G; Pearce, J Andrew; Hansen, Diana S; Cowman, Alan F; Schofield, Louis

2007-08-16

Plasmodium falciparum erythrocyte membrane protein-1 (PfEMP-1) is a variable antigen expressed by P. falciparum, the malarial parasite. PfEMP-1, present on the surface of infected host erythrocytes, mediates erythrocyte binding to vascular endothelium, enabling the parasite to avoid splenic clearance. In addition, PfEMP-1 is proposed to regulate host immune responses via interactions with the CD36 receptor on antigen-presenting cells. We investigated the immunoregulatory function of PfEMP-1 by comparing host cell responses to erythrocytes infected with either wild-type parasites or transgenic parasites lacking PfEMP-1. We showed that PfEMP-1 suppresses the production of the cytokine interferon-gamma by human peripheral blood mononuclear cells early after exposure to P. falciparum. Suppression of this rapid proinflammatory response was CD36 independent and specific to interferon-gamma production by gammadelta-T, NK, and alphabeta-T cells. These data demonstrate a parasite strategy for downregulating the proinflammatory interferon-gamma response and further establish transgenic parasites lacking PfEMP-1 as powerful tools for elucidating PfEMP-1 functions.

Investigation on Polylactide (PLA)/Poly(butylene adipate-co-terephthalate) (PBAT)/Bark Flour of Plane Tree (PF) Eco-Composites

PubMed Central

Dou, Qiang; Cai, Jun

2016-01-01

Polylactide (PLA)/poly(butylene adipate-co-terephthalate) (PBAT)/bark flour of plane tree (PF) eco-composites were prepared via melt blending. The morphologies, mechanical properties, crystal structures and melting and crystallization behaviors of the eco-composites were investigated by means of scanning electron microscopy (SEM), mechanical tests, polarized light microscopy (PLM), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC), respectively. It is shown that the interfacial adhesion between PLA matrix and PF is weak and the mechanical properties of PLA/PF eco-composites are poor. The titanate treatment improves the adhesion between the matrix and the filler and enhances the stiffness of the eco-composites. The toughness is improved by PBAT and ductile fractured surfaces can be found. The spherulitic size of PLA is decreased by the addition of PF. The α crystalline form of PLA remains in the composites. Compared with PF, T-PF (PF treated by a titanate coupling agent) and PBAT have negative effects on the crystallization of PLA. PMID:28773515

Interaction of PF4 (CXCL4) with the vasculature: a role in atherosclerosis and angiogenesis.

PubMed

Aidoudi, Sallouha; Bikfalvi, Andreas

2010-11-01

Platelet factor-4 (PF4), a platelet-derived chemokine, has two important functions in the vasculature. It has a pro-atherogenic role while also having anti-angiogenic effects. The activity of platelet factor-4 (PF4), unlike other chemokines that bind to specific receptors, depends on its unusually high affinity for proteoglycans and other negatively charged molecules. High affinity for heparan sulfates was thought to be central to all of PF4's biological functions. However, other mechanisms have been described such as direct growth factor binding, activation of the CXCR3B chemokine receptor isoform that is present in some vascular cells or binding to lipoprotein-related protein-1 (LRP1). Furthermore, PF4 also binds to integrins with affinities similar to matrix molecules. These interactions may explain the effects of PF4 in healthy and pathological tissues. However, the mechanisms involved in PF4's activity are complex and may depend on a given tissue or localisation. Overall, while much is already known about PF4, its specific role in atherosclerosis and angiogenesis remains still to be clarified.

A homeodomain transcription factor gene, PfMSX, activates expression of Pif gene in the pearl oyster Pinctada fucata.

PubMed

Zhao, Mi; He, Maoxian; Huang, Xiande; Wang, Qi

2014-01-01

We reported pearl oyster Pinctada fucata cDNA and genomic characterization of a new homeobox-containing protein, PfMSX. The PfMSX gene encodes a transcription factor that was localized to the nucleus. Analyses of PfMSX mRNA in tissues and developmental stages showed high expressions in mantle or D-shaped larvae. In electrophoretic mobility shift assays (EMSAs) PfMSX binded to MSX consensus binding sites in the 5' flanking region of the Pif promoter. In co-transfection experiment PfMSX transactivated reporter constructs containing Pif promoter sequences, and mutation of the MSX-binding sites attenuated transactivation. A knockdown experiment using PfMSX dsRNA showed decreased Pif mRNA and unregular crystallization of the nacreous layer using scanning electron microscopy. Our results suggested that PfMSX was a conserved homeodomain transcription factor gene, which can activate Pif gene expression through MSX binding site, and was then involved in the mineralization process in pearl oyster Pinctada fucata. Our data provided important clues about mechanisms regulating biomineralization in pearl oyster.

Characterization and Structural Studies of the Plasmodium falciparum Ubiquitin and Nedd8 Hydrolase UCHL3

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

Artavanis-Tsakonas, Katerina; Weihofen, Wilhelm A.; Antos, John M.

Like their human hosts, Plasmodium falciparum parasites rely on the ubiquitin-proteasome system for survival. We previously identified PfUCHL3, a deubiquitinating enzyme, and here we characterize its activity and changes in active site architecture upon binding to ubiquitin. We find strong evidence that PfUCHL3 is essential to parasite survival. The crystal structures of both PfUCHL3 alone and in complex with the ubiquitin-based suicide substrate UbVME suggest a rather rigid active site crossover loop that likely plays a role in restricting the size of ubiquitin adduct substrates. Molecular dynamics simulations of the structures and a model of the PfUCHL3-PfNedd8 complex allowed themore » identification of shared key interactions of ubiquitin and PfNedd8 with PfUCHL3, explaining the dual specificity of this enzyme. Distinct differences observed in ubiquitin binding between PfUCHL3 and its human counterpart make it likely that the parasitic DUB can be selectively targeted while leaving the human enzyme unaffected.« less

A Homeodomain Transcription Factor Gene, PfMSX, Activates Expression of Pif Gene in the Pearl Oyster Pinctada fucata

PubMed Central

Zhao, Mi; He, Maoxian; Huang, Xiande; Wang, Qi

2014-01-01

We reported pearl oyster Pinctada fucata cDNA and genomic characterization of a new homeobox-containing protein, PfMSX. The PfMSX gene encodes a transcription factor that was localized to the nucleus. Analyses of PfMSX mRNA in tissues and developmental stages showed high expressions in mantle or D-shaped larvae. In electrophoretic mobility shift assays (EMSAs) PfMSX binded to MSX consensus binding sites in the 5′ flanking region of the Pif promoter. In co-transfection experiment PfMSX transactivated reporter constructs containing Pif promoter sequences, and mutation of the MSX-binding sites attenuated transactivation. A knockdown experiment using PfMSX dsRNA showed decreased Pif mRNA and unregular crystallization of the nacreous layer using scanning electron microscopy. Our results suggested that PfMSX was a conserved homeodomain transcription factor gene, which can activate Pif gene expression through MSX binding site, and was then involved in the mineralization process in pearl oyster Pinctada fucata. Our data provided important clues about mechanisms regulating biomineralization in pearl oyster. PMID:25099698

Iron stores of breastfed infants during the first year of life.

PubMed

Ziegler, Ekhard E; Nelson, Steven E; Jeter, Janice M

2014-05-21

The birth iron endowment provides iron for growth in the first months of life. We describe the iron endowment under conditions of low dietary iron supply. Subjects were infants participating in a trial of Vitamin D supplementation from 1 to 9 months. Infants were exclusively breastfed at enrollment but could receive complementary foods from 4 months but not formula. Plasma ferritin (PF) and transferrin receptor (TfR) were determined at 1, 2, 4, 5.5, 7.5, 9 and 12 months. At 1 month PF ranged from 38 to 752 µg/L and was only weakly related to maternal PF. PF declined subsequently and flattened out at 5.5 months. PF of females was significantly higher than PF of males except at 12 months. TfR increased with age and was inversely correlated with PF. PF and TfR tracked strongly until 9 months. Iron deficiency (PF < 10 µg/L) began to appear at 4 months and increased in frequency until 9 months. Infants with ID were born with low iron endowment. We concluded that the birth iron endowment is highly variable in size and a small endowment places infants at risk of iron deficiency before 6 months. Boys have smaller iron endowments and are at greater risk of iron deficiency than girls.

Photoaffinity Labeling of the Plasmodium falciparum Chloroquine Resistance Transporter with a Novel Perfluorophenylazido Chloroquine†

PubMed Central

Lekostaj, Jacqueline K.; Natarajan, Jayakumar K.; Paguio, Michelle F.; Wolf, Christian; Roepe, Paul D.

2009-01-01

Several models describing how amino acid substitutions in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) confer resistance to chloroquine (CQ) and other antimalarial drugs have been proposed. Further progress requires molecular analysis of interactions between purified reconstituted PfCRT protein and these drugs. We have thus designed and synthesized several perfluorophenyl azido (pfpa) CQ analogues for PfCRT photolabeling studies. One particularly useful probe (AzBCQ) places the pfpa group at the terminal aliphatic N of CQ via a flexible four-carbon ester linker and includes a convenient biotin tag. This probe photolabels PfCRT in situ with high specificity. Using reconstituted proteoliposomes harboring partially purified recombinant PfCRT, we analyze AzBCQ photolabeling versus competition with CQ and other drugs to probe the nature of the CQ binding site. We also inspect how pH, the chemoreversal agent verapamil (VPL), and various amino acid mutations in PfCRT that cause CQ resistance (CQR) affect the efficiency of AzBCQ photolabeling. Upon gel isolation of AzBCQ-labeled PfCRT followed by trypsin digestion and mass spectrometry analysis, we are able to define a single AzBCQ covalent attachment site lying within the digestive vacuolar-disposed loop between putative helices 9 and 10 of PfCRT. Taken together, the data provide important new insight into PfCRT function and, along with previous results, allow us to propose a model for a single CQ binding site in the PfCRT protein. PMID:18767816

Photoaffinity labeling of the Plasmodium falciparum chloroquine resistance transporter with a novel perfluorophenylazido chloroquine.

PubMed

Lekostaj, Jacqueline K; Natarajan, Jayakumar K; Paguio, Michelle F; Wolf, Christian; Roepe, Paul D

2008-09-30

Several models describing how amino acid substitutions in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) confer resistance to chloroquine (CQ) and other antimalarial drugs have been proposed. Further progress requires molecular analysis of interactions between purified reconstituted PfCRT protein and these drugs. We have thus designed and synthesized several perfluorophenyl azido (pfpa) CQ analogues for PfCRT photolabeling studies. One particularly useful probe (AzBCQ) places the pfpa group at the terminal aliphatic N of CQ via a flexible four-carbon ester linker and includes a convenient biotin tag. This probe photolabels PfCRT in situ with high specificity. Using reconstituted proteoliposomes harboring partially purified recombinant PfCRT, we analyze AzBCQ photolabeling versus competition with CQ and other drugs to probe the nature of the CQ binding site. We also inspect how pH, the chemoreversal agent verapamil (VPL), and various amino acid mutations in PfCRT that cause CQ resistance (CQR) affect the efficiency of AzBCQ photolabeling. Upon gel isolation of AzBCQ-labeled PfCRT followed by trypsin digestion and mass spectrometry analysis, we are able to define a single AzBCQ covalent attachment site lying within the digestive vacuolar-disposed loop between putative helices 9 and 10 of PfCRT. Taken together, the data provide important new insight into PfCRT function and, along with previous results, allow us to propose a model for a single CQ binding site in the PfCRT protein.

The Clp Chaperones and Proteases of the Human Malaria Parasite Plasmodium falciparum

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

Bakkouri, Majida El; Pow, Andre; Mulichak, Anne

The Clp chaperones and proteases play an important role in protein homeostasis in the cell. They are highly conserved across prokaryotes and found also in the mitochondria of eukaryotes and the chloroplasts of plants. They function mainly in the disaggregation, unfolding and degradation of native as well as misfolded proteins. Here, we provide a comprehensive analysis of the Clp chaperones and proteases in the human malaria parasite Plasmodium falciparum. The parasite contains four Clp ATPases, which we term PfClpB1, PfClpB2, PfClpC and PfClpM. One PfClpP, the proteolytic subunit, and one PfClpR, which is an inactive version of the protease, weremore » also identified. Expression of all Clp chaperones and proteases was confirmed in blood-stage parasites. The proteins were localized to the apicoplast, a non-photosynthetic organelle that accommodates several important metabolic pathways in P. falciparum, with the exception of PfClpB2 (also known as Hsp101), which was found in the parasitophorous vacuole. Both PfClpP and PfClpR form mostly homoheptameric rings as observed by size-exclusion chromatography, analytical ultracentrifugation and electron microscopy. The X-ray structure of PfClpP showed the protein as a compacted tetradecamer similar to that observed for Streptococcus pneumoniae and Mycobacterium tuberculosis ClpPs. Our data suggest the presence of a ClpCRP complex in the apicoplast of P. falciparum.« less

Nematicidal protease genes screened from a soil metagenomic library to control Radopholus similis mediated by Pseudomonas fluorescens pf36.

PubMed

Chen, Deqiang; Wang, Dongwei; Xu, Chunling; Chen, Chun; Li, Junyi; Wu, Wenjia; Huang, Xin; Xie, Hui

2018-04-01

Controlling Radopholus similis, an important phytopathogenic nematode, is a challenge worldwide. Herein, we constructed a metagenomic fosmid library from the rhizosphere soil of banana plants, and six clones with protease activity were obtained by functionally screening the library. Furthermore, subclones were constructed using the six clones, and three protease genes with nematicidal activity were identified: pase1, pase4, and pase6. The pase4 gene was successfully cloned and expressed, demonstrating that the protease PASE4 could effectively degrade R. similis tissues and result in nematode death. Additionally, we isolated a predominant R. similis-associated bacterium, Pseudomonas fluorescens (pf36), from 10 R. similis populations with different hosts. The pase4 gene was successfully introduced into the pf36 strain by vector transformation and conjugative transposition, and two genetically modified strains were obtained: p4MCS-pf36 and p4Tn5-pf36. p4MCS-pf36 had significantly higher protease expression and nematicidal activity (p < 0.05) than p4Tn5-pf36 in a microtiter plate assay, whereas p4Tn5-pf36 was superior to p4MCS-pf36 in terms of genetic stability and controlling R. similis in growth pot tests. This study confirmed that R. similis is inhibited by the associated bacterium pf36-mediated expression of nematicidal proteases. Herein, a novel approach is provided for the study and development of efficient, environmentally friendly, and sustainable biocontrol techniques against phytonematodes.

Triazole-functionalized N-heterocyclic carbene complexes of palladium and platinum and efficient aqueous Suzuki-Miyaura coupling reaction.

PubMed

Gu, Shaojin; Xu, Hui; Zhang, Na; Chen, Wanzhi

2010-07-05

Imidazolium salts bearing triazole groups are synthesized via a copper catalyzed click reaction, and the silver, palladium, and platinum complexes of their N-heterocyclic carbenes are studied. [Ag(4)(L1)(4)](PF(6))(4), [Pd(L1)Cl](PF(6)), [Pt(L1)Cl](PF(6)) (L1=3-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)-1-(pyrimidin-2-yl)-1H-imidazolylidene), [Pd(2)(L2)(2)Cl(2)](PF(6))(2), and [Pd(L2)(2)](PF(6))(2) (L2=1-butyl-3-((1-(pyridin-2-yl)-1H-1,2,3-triazol-4-yl)methyl)imidazolylidene) have been synthesized and fully characterized by NMR, elemental analysis, and X-ray crystallography. The silver complex [Ag(4)(L1)(4)](PF(6))(4) consists of a Ag(4) zigzag chain. The complexes [Pd(L1)Cl](PF(6)) and [Pt(L1)Cl](PF(6)), containing a nonsymmetrical NCN' pincer ligand, are square planar with a chloride trans to the carbene donor. [Pd(2)(L2)(2)Cl(2)](PF(6))(2) consists of two palladium centers with CN(2)Cl coordination mode, whereas the palladium in [Pd(L2)(2)](PF(6))(2) is surrounded by two carbene and two triazole groups with two uncoordinated pyridines. The palladium compounds are highly active for Suzuki-Miyaura cross coupling reactions of aryl bromides and 1,1-dibromo-1-alkenes in neat water under an air atmosphere.

Immune complexes formed following the binding of anti-platelet factor 4 (CXCL4) antibodies to CXCL4 stimulate human neutrophil activation and cell adhesion.

PubMed

Xiao, Zhihua; Visentin, Gian P; Dayananda, Kannayakanahalli M; Neelamegham, Sriram

2008-08-15

We tested the possibility that immune complexes formed following platelet factor 4 (PF4/CXCL4) binding to anti-PF4 antibody can stimulate neutrophil activation, similar to previous reports with platelets. Monoclonal Abs against PF4 and IgG from a heparin-induced thrombocytopenia (HIT) patient were applied. We observed that although PF4 or anti-PF4 antibody alone did not alter neutrophil function, costimulation with both reagents resulted in approximately 3-fold increase in cell surface Mac-1 expression, enhanced cell adhesion via L-selectin and CD18 integrins, and degranulation of secondary and tertiary granules. The level of Mac-1 up-regulation peaked at an intermediate PF4 dose, suggesting that functional response varies with antigen-antibody stoichiometry. PF4 binding to neutrophils was blocked by chondroitinase ABC. Cell activation was inhibited by both chondroitinase ABC and anti-CD32/FcgammaRII blocking mAb, IV.3. Confocal microscopy demonstrated that immune complexes colocalize with CD32a. Studies with HIT IgG demonstrated that neutrophils could be activated in the absence of exogenous heparin. These data, together, show that leukocyte surface chondroitin sulfates promote neutrophil activation by enhancing immune-complex binding to CD32a. Studies with recombinant PF4 suggest a role for arginine 49 in stabilizing PF4-chondroitin binding. Neutrophils activated via this mechanism may contribute to thrombosis and inflammation in patients mounting an immune response to PF4-heparin.

Investigation of a Potential Protective Mechanism Against Heparin-Induced Thrombocytopenia in Patients on Chronic Intermittent Hemodialysis

PubMed Central

Tanhehco, Yvette C.; Cuker, Adam; Rudnick, Michael; Sachais, Bruce S.

2015-01-01

BACKGROUND Heparin-induced thrombocytopenia (HIT) develops as a result of platelet (PLT) activation by anti-platelet factor 4 (PF4)/heparin complex antibodies. Despite repeated exposure to heparin, patients undergoing chronic intermittent hemodialysis (HD) rarely develop HIT. We investigated the possibility that HD decreases/removes PF4 from PLT surfaces and/or plasma, thereby disfavoring immune complex formation as a mechanism of protection against HIT. MATERIALS AND METHODS We enrolled 20 patients undergoing chronic HD at the Penn Presbyterian Medical Center. Blood samples were drawn before, during and after treatment in the presence and absence of heparin. PF4, PF4/heparin antibody, heparin, and P-selectin levels were measured. RESULTS No patients demonstrated clinical symptoms of HIT. PLT surface PF4 levels decreased and plasma PF4 levels increased concurrently with increase in plasma heparin concentration. In the absence of heparin, PLT surface and plasma PF4 levels were unchanged. Anti-PF4/heparin antibodies, which were non-functional by the serotonin release assay, were detectable in 8 patients. PLT surface P-selectin levels did not change during treatment. CONCLUSIONS Removal of PLT surface and/or plasma PF4 as a mechanism of protection against HIT in patients undergoing HD is not supported by the results of our study, although the transient decrease in PLT surface PF4 in the presence of large amounts of heparin remains a candidate mechanism. The small sample size, single type of dialyzer membrane, and early sampling time points may have led to the inability to detect changes in PF4 levels. Future studies should explore other potential protective mechanisms. PMID:23305841

The influence of transection site on the development of pancreatic fistula in patients undergoing distal pancreatectomy: A review of 294 consecutive cases.

PubMed

Sell, Naomi M; Pucci, Michael J; Gabale, Salil; Leiby, Benjamin E; Rosato, Ernest L; Winter, Jordan M; Yeo, Charles J; Lavu, Harish

2015-06-01

Pancreatic fistula (PF) is a significant cause of morbidity in patients undergoing distal pancreatectomy (DP), with an incidence of 15-40%. It remains unclear if the location of pancreatic transection affects the rate of PF occurrence. This study examines the correlation between the transection site of the pancreas during DP and the incidence of PF. All cases of DP from October 2005 to January 2012 were reviewed retrospectively from an institutional review board-approved database at the Thomas Jefferson University Hospital. Patient demographics and perioperative outcomes were analyzed. The pancreatic transection location was determined by review of operative reports, and then dichotomized into 2 groups: neck/body or tail. PF were graded following the International Study Group on Pancreatic Fistula guidelines. During the study period, 294 DP were performed with 244 pancreas transections at the neck/body and 50 at the tail. Of the 294 patients, 52 (17.7%) developed a postoperative PF. The incidence of PF after transection at the tail of the pancreas was higher (28%) when compared with transection at the neck/body (15.6%; P = .04). When stratified by PF grade, grade A PF occurred more commonly when transection of the gland was at the tail (22% tail vs 8.2% neck/body; P = .007); however, no difference was found for grade B/C PF (6% tail vs 7.4% neck/body; P = 1). Our data suggest that PF occurs more often when the tail is transected during DP, although the majority are low grade and of minimal clinical significance. More severe PF occurred equally between the transection sites. Copyright © 2015 Elsevier Inc. All rights reserved.

Metabolic programming effects initiated in the suckling period predisposing for adult-onset obesity cannot be reversed by calorie restriction.

PubMed

Srinivasan, Malathi; Mahmood, Saleh; Patel, Mulchand S

2013-03-01

Neonatal rats reared on high-carbohydrate (HC) milk formula developed chronic hyperinsulinemia and adult-onset obesity due to programming of islets and the hypothalamic energy circuitry. In this study, calorie restriction by pair-feeding was imposed on HC male rats (HC/PF) to normalize food intake similar to that of mother-fed (MF) rats from weaning until postnatal day 140. A group of HC/PF rats was switched over to ad libitum feeding (HC/PF/AL) from days 90 to 140. Pair-feeding reduced body weight gains and serum insulin and leptin levels in HC/PF rats compared with HC rats, but these parameters were restored to HC levels in the HC/PF/AL rats after ad libitum feeding. Interestingly, the heightened insulin secretory response of isolated islets from adult HC/PF and HC/PF/ AL rats to glucose, acetylcholine, and oxymetazoline were not significantly different from the responses of islets from HC rats. Similarly, the expression of neuropeptide Y and proopiomelanocortin in the hypothalamus was not significantly different among HC, HC/PF, and HC/PF/AL rats. Expression of the leptin receptor in the hypothalami from the HC, HC/PF, and HC/PF/AL rats mirrored that of serum leptin, whereas suppressor of cytokine signaling 3 (Socs3) expression remained high in these three groups. The results indicate that, although calorie restriction resulted in reduction in body weight gain and normalized the serum hormonal pattern, the programed predisposition for the hypersecretory capacity of islets and the hypothalamic hyperphagic response in the HC rats could not be permanently overcome by the pair-feeding imposed on HC rats.

Effects of peritoneal fluid from endometriosis patients on interferon-gamma-induced protein-10 (CXCL10) and interleukin-8 (CXCL8) released by neutrophils and CD4+ T cells.

PubMed

Kim, Ji-Yeon; Lee, Dong-Hyung; Joo, Jong-Kil; Jin, Jun-O; Wang, Ji-Won; Hong, Young-Seoub; Kwak, Jong-Young; Lee, Kyu-Sup

2009-09-01

Intraperitoneal immuno-inflammatory changes may be associated with the pathogenesis of endometriosis. We evaluated the effects of peritoneal fluid obtained from patients with endometriosis (ePF) on the release of interferon-gamma-induced protein-10 (IP-10/CXCL10) and interleukin-8 (IL-8/CXCL8) by neutrophils, CD4(+) T cells, and monocytes. Neutrophils, CD4(+) T cells, and monocytes were cultured with ePF and the chemokine levels in the supernatants were then measured using enzyme-linked immunosorbent assay. The addition of ePF to cultures of CD4(+) T cells led to a significant increase in the release of IP-10 when compared with control PF without endometriosis (cPF). There was a positive correlation between the levels of IL-8 and IP-10 in ePF (R = 0.89, P = 0.041), but not between the levels of IP-10 and IL-8 released by neutrophils, CD4(+) T cells, and monocytes. The levels of IP-10 in ePF were positively correlated with the release of IP-10 by ePF-treated neutrophils (R = 0.89, P < 0.001), CD4(+) T cells (R = 0.93, P < 0.001), and monocytes (R = 0.70, P = 0.01). Moreover, the addition of ePF significantly enhanced the interferon-gamma-induced release of IP-10 by nuetrophils and CD4(+) T cells. These findings suggest that neutrophils and T cells release differential levels of IP-10 and IL-8 in response to stimulation with ePF, and that these cells are a major source of IP-10 in the PF of endometriosis patients.

The effects of 18β-glycyrrhetinic acid and glycyrrhizin on intestinal absorption of paeoniflorin using the everted rat gut sac model.

PubMed

He, Rui; Xu, Yongsong; Peng, Jingjing; Ma, Tingting; Li, Jing; Gong, Muxin

2017-01-01

Paeoniflorin (PF), the main active component of Shaoyao-Gancao-tang, possesses significantly antinociceptive effects and many other pharmacological activities. However, its poor intestinal absorption results in low bioavailability. Therefore, enhancing PF absorption plays a vital role in exerting its therapeutic effect. Shaoyao combined with Gancao exhibited a synergistic effect. The enhancement of PF absorption through the interaction of its constituents in intestinal absorption would be greatly implicated. The present study aimed at investigating the effects of glycyrrhizin, the main constituent of Gancao, and its main metabolite, 18β-glycyrrhetinic acid (18β-GA), on the intestinal absorptive behavior of PF, and the role of P-glycoprotein (P-gp) in PF absorption using the in vitro everted rat gut sac model. The results demonstrated that 1 mM of 18β-GA significantly increased PF absorption in both the jejunum and the ileum, while 100 μM of 18β-GA only promoted the ileum absorption and had no obvious effect on the jejunum absorption. The effect of glycyrrhizin on intestinal PF absorption was related to concentrations. One mM of glycyrrhizin significantly increased PF absorption in the jejunum after 45 min and in the ileum after 90 min. But 100 μM of glycyrrhizin had an inhibitory effect in the jejunum and no effect in the ileum before 60 min. Moreover, verapamil, the well-known P-gp inhibitor, could significantly enhance the PF absorption. In conclusion, the influence of 18β-GA and glycyrrhizin on the PF absorption was related to concentrations and intestinal segments. This might be involved in the intervention of efflux transport of PF mediated by intestinal P-gp.

Human autoantibodies against a desmosomal core protein in pemphigus foliaceus

PubMed Central

1984-01-01

Pemphigus foliaceus (PF) is a human autoimmune disease in which antibodies are directed against the cell surface of epidermal cells with resultant blister formation. The histopathology of these blisters indicates that cells have detached from each other, and electron microscopy of early blisters shows diminished numbers, to complete loss, of desmosomes as well as abnormalities of the tonofilament- desmosome complex. In this study we demonstrate that autoantibodies from certain PF patients bind to a desmosomal core glycoprotein called desmoglein (DG) I. Proteins in extracts of normal human epidermis were separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE), then transferred to nitrocellulose or 2- aminophenylthioether paper for immunoperoxidase staining. Results of these immunoblots indicated that sera from 6 of 13 PF patients specifically and intensely stained an approximately 160,000 mol wt polypeptide, "PF antigen". Such staining was not seen with normal human sera or sera from patients with pemphigus vulgaris or bullous pemphigoid, two autoimmune blistering skin diseases that are clinically, histologically, and immunochemically distinct from PF. However, rabbit antiserum directed against DGI, that was isolated from bovine muzzle desmosomes, stained a polypeptide band which co-migrated with PF antigen. Furthermore, when proteins from extracts of normal human epidermis were electrophoresed in two dimensions (isoelectric focusing, then SDS-PAGE) before transfer to nitrocellulose for immunoperoxidase staining, PF antibodies and antibodies to DGI stained identical spots. Finally, PF sera as well as PF IgG that was affinity purified with PF antigen from normal human epidermis, both selectively bound to DGI extracted from bovine muzzle desmosomes. These studies demonstrate that the human autoantibodies from certain patients with PF, a disease of epidermal cell adhesion, are directed against a desmosomal core protein. PMID:6491602

Somatic cells initiate primordial follicle activation and govern the development of dormant oocytes in mice.

PubMed

Zhang, Hua; Risal, Sanjiv; Gorre, Nagaraju; Busayavalasa, Kiran; Li, Xin; Shen, Yan; Bosbach, Benedikt; Brännström, Mats; Liu, Kui

2014-11-03

The majority of oocytes in the mammalian ovary are dormant oocytes that are enclosed in primordial follicles by several somatic cells, which we refer to as primordial follicle granulosa cells (pfGCs). Very little is known, however, about how the pfGCs control the activation of primordial follicles and the developmental fates of dormant oocytes. By targeting molecules in pfGCs with several mutant mouse models, we demonstrate that the somatic pfGCs initiate the activation of primordial follicles and govern the quiescence or awakening of dormant oocytes. Inhibition of mTORC1 signaling in pfGCs prevents the differentiation of pfGCs into granulosa cells, and this arrests the dormant oocytes in their quiescent states, leading to oocyte death. Overactivation of mTORC1 signaling in pfGCs accelerates the differentiation of pfGCs into granulosa cells and causes premature activation of all dormant oocytes and primordial follicles. We further show that pfGCs trigger the awakening of dormant oocytes through KIT ligand (KITL), and we present an essential communication network between the somatic cells and germ cells that is based on signaling between the mTORC1-KITL cascade in pfGCs and KIT-PI3K signaling in oocytes. Our findings provide a relatively complete picture of how mammalian primordial follicles are activated. The microenvironment surrounding primordial follicles can activate mTORC1-KITL signaling in pfGCs, and these cells trigger the awakening of dormant oocytes and complete the process of follicular activation. Such communication between the microenvironment, somatic cells, and germ cells is essential to maintaining the proper reproductive lifespan in mammals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Oxygen Isotope Variability within Nautilus Shell Growth Bands

PubMed Central

2016-01-01

Nautilus is often used as an analogue for the ecology and behavior of extinct externally shelled cephalopods. Nautilus shell grows quickly, has internal growth banding, and is widely believed to precipitate aragonite in oxygen isotope equilibrium with seawater. Pieces of shell from a wild-caught Nautilus macromphalus from New Caledonia and from a Nautilus belauensis reared in an aquarium were cast in epoxy, polished, and then imaged. Growth bands were visible in the outer prismatic layer of both shells. The thicknesses of the bands are consistent with previously reported daily growth rates measured in aquarium reared individuals. In situ analysis of oxygen isotope ratios using secondary ion mass spectrometry (SIMS) with 10 μm beam-spot size reveals inter- and intra-band δ18O variation. In the wild-caught sample, a traverse crosscutting 45 growth bands yielded δ18O values ranging 2.5‰, from +0.9 to -1.6 ‰ (VPDB), a range that is larger than that observed in many serial sampling of entire shells by conventional methods. The maximum range within a single band (~32 μm) was 1.5‰, and 27 out of 41 bands had a range larger than instrumental precision (±2 SD = 0.6‰). The results from the wild individual suggest depth migration is recorded by the shell, but are not consistent with a simple sinusoidal, diurnal depth change pattern. To create the observed range of δ18O, however, this Nautilus must have traversed a temperature gradient of at least ~12°C, corresponding to approximately 400 m depth change. Isotopic variation was also measured in the aquarium-reared sample, but the pattern within and between bands likely reflects evaporative enrichment arising from a weekly cycle of refill and replacement of the aquarium water. Overall, this work suggests that depth migration behavior in ancient nektonic mollusks could be elucidated by SIMS analysis across individual growth bands. PMID:27100183

Oxygen isotope variability within Nautilus shell growth bands

DOE PAGES

Linzmeier, Benjamin J.; Kozdon, Reinhard; Peters, Shanan E.; ...

2016-04-21

Nautilus is often used as an analogue for the ecology and behavior of extinct externally shelled cephalopods. Nautilus shell grows quickly, has internal growth banding, and is widely believed to precipitate aragonite in oxygen isotope equilibrium with seawater. Pieces of shell from a wild-caught Nautilus macromphalus from New Caledonia and from a Nautilus belauensis reared in an aquarium were cast in epoxy, polished, and then imaged. Growth bands were visible in the outer prismatic layer of both shells. The thicknesses of the bands are consistent with previously reported daily growth rates measured in aquarium reared individuals. In situ analysis ofmore » oxygen isotope ratios using secondary ion mass spectrometry (SIMS) with 10 μm beam-spot size reveals inter- and intra-band δ 18O variation. In the wild-caught sample, a traverse crosscutting 45 growth bands yielded δ 18O values ranging 2.5‰, from +0.9 to -1.6 ‰ (VPDB), a range that is larger than that observed in many serial sampling of entire shells by conventional methods. The maximum range within a single band (~32 μm) was 1.5‰, and 27 out of 41 bands had a range larger than instrumental precision (±2 SD = 0.6‰). The results from the wild individual suggest depth migration is recorded by the shell, but are not consistent with a simple sinusoidal, diurnal depth change pattern. In addition, to create the observed range of δ 18O, however, this Nautilus must have traversed a temperature gradient of at least ~12°C, corresponding to approximately 400 m depth change. Isotopic variation was also measured in the aquarium-reared sample, but the pattern within and between bands likely reflects evaporative enrichment arising from a weekly cycle of refill and replacement of the aquarium water. Overall, this work suggests that depth migration behavior in ancient nektonic mollusks could be elucidated by SIMS analysis across individual growth bands.« less

Assessment of the Plasmodium falciparum Preerythrocytic Antigen UIS3 as a Potential Candidate for a Malaria Vaccine.

PubMed

Longley, Rhea J; Halbroth, Benedict R; Salman, Ahmed M; Ewer, Katie J; Hodgson, Susanne H; Janse, Chris J; Khan, Shahid M; Hill, Adrian V S; Spencer, Alexandra J

2017-03-01

Efforts are under way to improve the efficacy of subunit malaria vaccines through assessments of new adjuvants, vaccination platforms, and antigens. In this study, we further assessed the Plasmodium falciparum antigen upregulated in infective sporozoites 3 (PfUIS3) as a vaccine candidate. PfUIS3 was expressed in the viral vectors chimpanzee adenovirus 63 (ChAd63) and modified vaccinia virus Ankara (MVA) and used to immunize mice in a prime-boost regimen. We previously demonstrated that this regimen could provide partial protection against challenge with chimeric P. berghei parasites expressing PfUIS3. We now show that ChAd63-MVA PfUIS3 can also provide partial cross-species protection against challenge with wild-type P. berghei parasites. We also show that PfUIS3-specific cellular memory responses could be recalled in human volunteers exposed to P. falciparum parasites in a controlled human malaria infection study. When ChAd63-MVA PfUIS3 was coadministered with the vaccine candidate P. falciparum thrombospondin-related adhesion protein (PfTRAP) expressed in the ChAd63-MVA system, there was no significant change in immunogenicity to either vaccine. However, when mice were challenged with double chimeric P. berghei - P. falciparum parasites expressing both PfUIS3 and PfTRAP, vaccine efficacy was improved to 100% sterile protection. This synergistic effect was evident only when the two vaccines were mixed and administered at the same site. We have therefore demonstrated that vaccination with PfUIS3 can induce a consistent delay in patent parasitemia across mouse strains and against chimeric parasites expressing PfUIS3 as well as wild-type P. berghei ; when this vaccine is combined with another partially protective regimen (ChAd63-MVA PfTRAP), complete protection is induced. Copyright © 2017 Longley et al.

Advancing Global Health through Development and Clinical Trials Partnerships: A Randomized, Placebo-Controlled, Double-Blind Assessment of Safety, Tolerability, and Immunogenicity of PfSPZ Vaccine for Malaria in Healthy Equatoguinean Men

PubMed Central

Olotu, Ally; Urbano, Vicente; Hamad, Ali; Eka, Martin; Chemba, Mwajuma; Nyakarungu, Elizabeth; Raso, Jose; Eburi, Esther; Mandumbi, Dolores O.; Hergott, Dianna; Maas, Carl D.; Ayekaba, Mitoha O.; Milang, Diosdado N.; Rivas, Matilde R.; Schindler, Tobias; Embon, Oscar M.; Ruben, Adam J.; Saverino, Elizabeth; Abebe, Yonas; KC, Natasha; James, Eric R.; Murshedkar, Tooba; Manoj, Anita; Chakravarty, Sumana; Li, Minglin; Adams, Matthew; Schwabe, Christopher; Segura, J. Luis; Daubenberger, Claudia; Tanner, Marcel; Richie, Thomas L.; Billingsley, Peter F.; Lee Sim, B. Kim; Abdulla, Salim; Hoffman, Stephen L.

2018-01-01

Abstract. Equatorial Guinea (EG) has implemented a successful malaria control program on Bioko Island. A highly effective vaccine would be an ideal complement to this effort and could lead to halting transmission and eliminating malaria. Sanaria® PfSPZ Vaccine (Plasmodium falciparum sporozoite Vaccine) is being developed for this purpose. To begin the process of establishing the efficacy of and implementing a PfSPZ Vaccine mass vaccination program in EG, we decided to conduct a series of clinical trials of PfSPZ Vaccine on Bioko Island. Because no clinical trial had ever been conducted in EG, we first successfully established the ethical, regulatory, quality, and clinical foundation for conducting trials. We now report the safety, tolerability, and immunogenicity results of the first clinical trial in the history of the country. Thirty adult males were randomized in the ratio 2:1 to receive three doses of 2.7 × 105 PfSPZ of PfSPZ Vaccine (N = 20) or normal saline placebo (N = 10) by direct venous inoculation at 8-week intervals. The vaccine was safe and well tolerated. Seventy percent, 65%, and 45% of vaccinees developed antibodies to Plasmodium falciparum (Pf) circumsporozoite protein (PfCSP) by enzyme-linked immunosorbent assay, PfSPZ by automated immunofluorescence assay, and PfSPZ by inhibition of sporozoite invasion assay, respectively. Antibody responses were significantly lower than responses in U.S. adults who received the same dosage regimen, but not significantly different than responses in young adult Malians. Based on these results, a clinical trial enrolling 135 subjects aged 6 months to 65 years has been initiated in EG; it includes PfSPZ Vaccine and first assessment in Africa of PfSPZ-CVac. ClinicalTrials.gov identifier: NCT02418962. PMID:29141739

Dose-Related Target Occupancy and Effects on Circuitry, Behavior, and Neuroplasticity of the Glycine Transporter-1 Inhibitor PF-03463275 in Healthy and Schizophrenia Subjects.

PubMed

D'Souza, Deepak Cyril; Carson, Richard E; Driesen, Naomi; Johannesen, Jason; Ranganathan, Mohini; Krystal, John H

2018-01-31

Glycine transporter-1 (GlyT1) inhibitors may ameliorate cognitive impairments associated with schizophrenia. The dose-related occupancy and target engagement of the GlyT1 inhibitor PF-03463275 were studied to inform optimal dose selection for a clinical trial for cognitive impairments associated with schizophrenia. In substudy 1, the effects of PF-03463275 (10, 20, and 40 mg twice a day) on occupancy of GlyT1 were tested using positron emission tomography and 18 F-MK-6577, and visual long-term potentiation (LTP) in schizophrenia patients (SZs) and healthy control subjects. Furthermore, the capacity of PF-03463275 to attenuate ketamine-induced disruption of working memory-related activation of a "working memory" circuit was tested only in healthy control subjects using functional magnetic resonance imaging. Subsequently, the effects of PF-03463275 (60 mg twice a day) on occupancy of GlyT1 and long-term potentiation were examined only in SZs (substudy 2). PF-03463275 at 10, 20, 40, and 60 mg twice a day produced ∼44%, 61%, 76%, and 83% GlyT1 occupancy, respectively, in SZs with higher ligand binding to GlyT1 in subcortical versus cortical regions. PF-03463275 did not attenuate any ketamine-induced effects but did improve working memory accuracy in healthy control subjects. PF-03463275 increased long-term potentiation only in SZs with peak effects at 40 mg twice a day (∼75% GlyT1 occupancy) and with a profile suggestive of an inverted U dose response. PF-03463275 was well-tolerated. The dose-related GlyT1 occupancy of PF-03463275 is linear. While PF-03463275 did not show evidence of facilitating N-methyl-D-aspartate receptor function in the ketamine assay, it enhanced neuroplasticity in SZs. These findings provide support for a clinical trial to test the ability of PF-03463275 to enhance cognitive remediation toward addressing cognitive impairments associated with schizophrenia. Published by Elsevier Inc.

Elucidation of Transport Mechanism of Paeoniflorin and the Influence of Ligustilide, Senkyunolide I and Senkyunolide A on Paeoniflorin Transport through Mdck-Mdr1 Cells as Blood-Brain Barrier in Vitro Model.

PubMed

Hu, Peng-Yi; Liu, Dan; Zheng, Qin; Wu, Qing; Tang, Yu; Yang, Ming

2016-03-02

The objectives of the present investigation were to: (1) elucidate the transport mechanism of paeoniflorin (PF) across MDCK-MDR1 monolayers; and (2) evaluate the effect of ligustilide (LIG), senkyunolide I (SENI) and senkyunolide A (SENA) on the transport of PF through blood-brain barrier so as to explore the enhancement mechanism. Transport studies of PF were performed in both directions, from apical to basolateral side (A→B) and from basolateral to apical sides (B→A). Drug concentrations were analyzed by LC-MS/MS. PF showed relatively poor absorption in MDCK-MDR1 cells, apparent permeability coefficients (Papp) ranging from 0.587 × 10(-6) to 0.705 × 10(-6) cm/s. In vitro experiments showed that the transport of PF in both directions was concentration dependent and not saturable. The B→A/A→B permeability ER of PF was more than 2 in the MDCK-MDR1 cells, which indicated that the transport mechanism of PF might be passive diffusion as the dominating process with the active transportation mediated mechanism involved. The increased Papp of PF in A→B direction by EDTA-Na₂ suggested that PF was absorbed via the paracellular route. The P-gp inhibitor verapamil could significantly increase the transport of PF in A→B direction, and ER decreased from 2.210 to 0.690, which indicated that PF was P-gp substance. The transport of PF in A→B direction significantly increased when co-administrated with increasing concentrations of LIG, SENI and SENA. An increased cellular accumulation of Rho 123 and Western blot analysis indicated that LIG, SENI and SENA had increased the transport of PF in the BBB models attribute to down-regulate P-gp expression. A decrease in transepithelial electrical resistance (TEER) during the permeation experiment can be explained by the modulation and opening of the tight junctions caused by the permeation enhancer LIG, SENI and SENA.

Moxifloxacin pharmacokinetics and pleural fluid penetration in patients with pleural effusion.

PubMed

Chatzika, Kalliopi; Manika, Katerina; Kontou, Paschalina; Pitsiou, Georgia; Papakosta, Despina; Zarogoulidis, Konstantinos; Kioumis, Ioannis

2014-01-01

The aim of this study was to evaluate the pharmacokinetics and penetration of moxifloxacin (MXF) in patients with various types of pleural effusion. Twelve patients with empyema/parapneumonic effusion (PPE) and 12 patients with malignant pleural effusion were enrolled in the study. A single-dose pharmacokinetic study was performed after intravenous administration of 400 mg MXF. Serial plasma (PL) and pleural fluid (PF) samples were collected during a 24-h time interval after drug administration. The MXF concentration in PL and PF was determined by high-performance liquid chromatography, and main pharmacokinetic parameters were estimated. Penetration of MXF in PF was determined by the ratio of the area under the concentration-time curve from time zero to 24 h (AUC24) in PF (AUC24PF) to the AUC24 in PL. No statistically significant differences in the pharmacokinetics in PL were observed between the two groups, despite the large interindividual variability in the volume of distribution, clearance, and elimination half-life. The maximum concentration in PF (CmaxPF) in patients with empyema/PPE was 2.23±1.31 mg/liter, and it was detected 7.50±2.39 h after the initiation of the infusion. In patients with malignant effusion, CmaxPF was 2.96±1.45 mg/liter, but it was observed significantly earlier, at 3.58±1.38 h (P<0.001). Both groups revealed similar values of AUC24PF (31.83±23.52 versus 32.81±12.66 mg·h/liter). Penetration of MXF into PF was similarly good in both patient groups (1.11±0.74 versus 1.17±0.39). Despite similar plasma pharmacokinetics, patients with empyema/parapneumonic effusion showed a significant delay in achievement of PF maximum MXF levels compared to those with malignant effusion. However, in both groups, the degree of MXF PF penetration and the on-site drug exposure, expressed by AUC24PF, did not differ according to the type of pleural effusion.

Bilateral comparison of 10 pF and 100 pF standards (ongoing BIPM key comparisons BIPM.EM-K14.a and 14.b) between the NMISA (South Africa) and the BIPM

NASA Astrophysics Data System (ADS)

Gournay, Pierre; Khoza, Michael

2017-01-01

This report presents the results of a bilateral comparison of 10 pF and 100 pF capacitance standards between the NMISA (South Africa) and the BIPM carried out in 2016. The comparison at 10 pF forms part of the ongoing BIPM key comparison BIPM.EM-K14.a and that at 100 pF of the ongoing BIPM key comparison BIPM.EM-K14.b. The BIPM is the pilot laboratory for both of these comparisons. Two 10 pF and 100 pF travelling standards belonging to the BIPM were used in this comparison carried out with an 'A-B-A' pattern of measurements. The standards were measured first at the BIPM for a period of about one month, then for a similar period at the NMISA, and finally again at the BIPM. The measurand was the two terminal-pair capacitance at a frequency of either 1000 Hz or 1592 Hz, for a measuring rms voltage of 15 V at 10 pF and 10 V at 100 pF. One of the 10 pF travelling standards had to be eliminated from the comparison due to a bistable behaviour, possibly due to transportation. The results from the NMISA and the BIPM at both 1000 Hz and 1592 Hz were found to be in good agreement, with a difference smaller than the relative expanded uncertainty (95 % confidence, k = 2) of maximum value 0.33 × 10-6 at 10 pF and 0.24 × 10-6 at 100 pF (and 1000 Hz in both cases). Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A new world malaria map: Plasmodium falciparum endemicity in 2010.

PubMed

Gething, Peter W; Patil, Anand P; Smith, David L; Guerra, Carlos A; Elyazar, Iqbal R F; Johnston, Geoffrey L; Tatem, Andrew J; Hay, Simon I

2011-12-20

Transmission intensity affects almost all aspects of malaria epidemiology and the impact of malaria on human populations. Maps of transmission intensity are necessary to identify populations at different levels of risk and to evaluate objectively options for disease control. To remain relevant operationally, such maps must be updated frequently. Following the first global effort to map Plasmodium falciparum malaria endemicity in 2007, this paper describes the generation of a new world map for the year 2010. This analysis is extended to provide the first global estimates of two other metrics of transmission intensity for P. falciparum that underpin contemporary questions in malaria control: the entomological inoculation rate (PfEIR) and the basic reproductive number (PfR). Annual parasite incidence data for 13,449 administrative units in 43 endemic countries were sourced to define the spatial limits of P. falciparum transmission in 2010 and 22,212 P. falciparum parasite rate (PfPR) surveys were used in a model-based geostatistical (MBG) prediction to create a continuous contemporary surface of malaria endemicity within these limits. A suite of transmission models were developed that link PfPR to PfEIR and PfR and these were fitted to field data. These models were combined with the PfPR map to create new global predictions of PfEIR and PfR. All output maps included measured uncertainty. An estimated 1.13 and 1.44 billion people worldwide were at risk of unstable and stable P. falciparum malaria, respectively. The majority of the endemic world was predicted with a median PfEIR of less than one and a median PfRc of less than two. Values of either metric exceeding 10 were almost exclusive to Africa. The uncertainty described in both PfEIR and PfR was substantial in regions of intense transmission. The year 2010 has a particular significance as an evaluation milestone for malaria global health policy. The maps presented here contribute to a rational basis for control and elimination decisions and can serve as a baseline assessment as the global health community looks ahead to the next series of milestones targeted at 2015.

The Colletotrichum boninense species complex

PubMed Central

Damm, U.; Cannon, P.F.; Woudenberg, J.H.C.; Johnston, P.R.; Weir, B.S.; Tan, Y.P.; Shivas, R.G.; Crous, P.W.

2012-01-01

Although only recently described, Colletotrichum boninense is well established in literature as an anthracnose pathogen or endophyte of a diverse range of host plants worldwide. It is especially prominent on members of Amaryllidaceae, Orchidaceae, Proteaceae and Solanaceae. Reports from literature and preliminary studies using ITS sequence data indicated that C. boninense represents a species complex. A multilocus molecular phylogenetic analysis (ITS, ACT, TUB2, CHS-1, GAPDH, HIS3, CAL) of 86 strains previously identified as C. boninense and other related strains revealed 18 clades. These clades are recognised here as separate species, including C. boninense s. str., C. hippeastri, C. karstii and 12 previously undescribed species, C. annellatum, C. beeveri, C. brassicicola, C. brasiliense, C. colombiense, C. constrictum, C. cymbidiicola, C. dacrycarpi, C. novae-zelandiae, C. oncidii, C. parsonsiae and C. torulosum. Seven of the new species are only known from New Zealand, perhaps reflecting a sampling bias. The new combination C. phyllanthi was made, and C. dracaenae Petch was epitypified and the name replaced with C. petchii. Typical for species of the C. boninense species complex are the conidiogenous cells with rather prominent periclinal thickening that also sometimes extend to form a new conidiogenous locus or annellations as well as conidia that have a prominent basal scar. Many species in the C. boninense complex form teleomorphs in culture. Taxonomic novelties: New combination - Colletotrichum phyllanthi (H. Surendranath Pai) Damm, P.F. Cannon & Crous. Name replacement - C. petchii Damm, P.F. Cannon & Crous. New species - C. annellatum Damm, P.F. Cannon & Crous, C. beeveri Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. brassicicola Damm, P.F. Cannon & Crous, C. brasiliense Damm, P.F. Cannon, Crous & Massola, C. colombiense Damm, P.F. Cannon, Crous, C. constrictum Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. cymbidiicola Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. dacrycarpi Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. novae-zelandiae Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. oncidii Damm, P.F. Cannon & Crous, C. parsonsiae Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir, C. torulosum Damm, P.F. Cannon, Crous, P.R. Johnst. & B. Weir. Typifications: Epitypifications - C. dracaenae Petch. PMID:23136457

Bipyrimidine ruthenium(II) arene complexes: structure, reactivity and cytotoxicity.

PubMed

Betanzos-Lara, Soledad; Novakova, Olga; Deeth, Robert J; Pizarro, Ana M; Clarkson, Guy J; Liskova, Barbora; Brabec, Viktor; Sadler, Peter J; Habtemariam, Abraha

2012-10-01

The synthesis and characterization of complexes [(η(6)-arene)Ru(N,N')X][PF(6)], where arene is para-cymene (p-cym), biphenyl (bip), ethyl benzoate (etb), hexamethylbenzene (hmb), indane (ind) or 1,2,3,4-tetrahydronaphthalene (thn), N,N' is 2,2'-bipyrimidine (bpm) and X is Cl, Br or I, are reported, including the X-ray crystal structures of [(η(6)-p-cym)Ru(bpm)I][PF(6)], [(η(6)-bip)Ru(bpm)Cl][PF(6)], [(η(6)-bip)Ru(bpm)I][PF(6)] and [(η(6)-etb)Ru(bpm)Cl][PF(6)]. Complexes in which N,N' is 1,10-phenanthroline (phen), 1,10-phenanthroline-5,6-dione or 4,7-diphenyl-1,10-phenanthroline (bathophen) were studied for comparison. The Ru(II) arene complexes undergo ligand-exchange reactions in aqueous solution at 310 K; their half-lives for hydrolysis range from 14 to 715 min. Density functional theory calculations on [(η(6)-p-cym)Ru(bpm)Cl][PF(6)], [(η(6)-p-cym)Ru(bpm)Br][PF(6)], [(η(6)-p-cym)Ru(bpm)I][PF(6)], [(η(6)-bip)Ru(bpm)Cl][PF(6)], [(η(6)-bip)Ru(bpm)Br][PF(6)] and [(η(6)-bip)Ru(bpm)I][PF(6)] suggest that aquation occurs via an associative pathway and that the reaction is thermodynamically favourable when the leaving ligand is I > Br ≈ Cl. pK (a)* values for the aqua adducts of the complexes range from 6.9 to 7.32. A binding preference for 9-ethylguanine (9-EtG) compared with 9-ethyladenine (9-EtA) was observed for [(η(6)-p-cym)Ru(bpm)Cl][PF(6)], [(η(6)-hmb)Ru(bpm)Cl](+), [(η(6)-ind)Ru(bpm)Cl](+), [(η(6)-thn)Ru(bpm)Cl](+), [(η(6)-p-cym)Ru(phen)Cl](+) and [(η(6)-p-cym)Ru(bathophen)Cl](+) in aqueous solution at 310 K. The X-ray crystal structure of the guanine complex [(η(6)-p-cym)Ru(bpm)(9-EtG-N7)][PF(6)](2) shows multiple hydrogen bonding. Density functional theory calculations show that the 9-EtG adducts of all complexes are thermodynamically preferred compared with those of 9-EtA. However, the bmp complexes are inactive towards A2780 human ovarian cancer cells. Calf thymus DNA interactions for [(η(6)-p-cym)Ru(bpm)Cl][PF(6)] and [(η(6)-p-cym)Ru(phen)Cl][PF(6)] consist of weak coordinative, intercalative and monofunctional coordination. Binding to biomolecules such as glutathione may play a role in deactivating the bpm complexes.

Inhibition of human megakaryocytopoiesis in vitro by platelet factor 4 (PF4) and a synthetic COOH-terminal PF4 peptide.

PubMed Central

Gewirtz, A M; Calabretta, B; Rucinski, B; Niewiarowski, S; Xu, W Y

1989-01-01

We report that highly purified human platelet factor 4 (PF4) inhibits human megakaryocytopoiesis in vitro. At greater than or equal to 25 micrograms/ml, PF4 inhibited megakaryocyte colony formation approximately 80% in unstimulated cultures, and approximately 58% in cultures containing recombinant human IL 3 and granulocyte-macrophage colony-stimulating factor. Because PF4 (25 micrograms/ml) had no effect on either myeloid or erythroid colony formation lineage specificity of this effect was suggested. A synthetic COOH-terminal PF4 peptide of 24, but not 13 residues, also inhibited megakaryocyte colony formation, whereas a synthetic 18-residue beta-thromboglobulin (beta-TG) peptide and native beta-TG had no such effect when assayed at similar concentrations. The mechanism of PF4-mediated inhibition was investigated. First, we enumerated total cell number, and examined cell maturation in control colonies (n = 200) and colonies (n = 100) that arose in PF4-containing cultures. Total cells per colony did not differ dramatically in the two groups (6.1 +/- 3.0 vs. 4.2 +/- 1.6, respectively), but the numbers of mature large cells per colony was significantly decreased in the presence of PF4 when compared with controls (1.6 +/- 1.5 vs. 3.9 +/- 2.3; P less than 0.001). Second, by using the human leukemia cell line HEL as a model for primitive megakaryocytic cells, we studied the effect of PF4 on cell doubling time, on the expression of both growth-regulated (H3, p53, c-myc,and c-myb), and non-growth-regulated (beta 2-microglobulin) genes. At high concentrations of native PF4 (50 micrograms/ml), no effect on cell doubling time, or H3 or p53 expression was discerned. In contrast, c-myc and c-myb were both upregulated. These results suggested the PF4 inhibited colony formation by impeding cell maturation, as opposed to cell proliferation, perhaps by inducing expression of c-myc and c-myb. The ability of PF4 to inhibit a normal cell maturation function was then tested. Megakaryocytes were incubated in synthetic PF4, or beta-TG peptides for 18 h and effect on Factor V steady-state mRNA levels was determined in 600 individual cells by in situ hybridization. beta-TG peptide had no effect on FV mRNA levels, whereas a approximately 60% decrease in expression of Factor V mRNA was found in megakaryocytes exposed to greater than or equal 100 ng/ml synthetic COOH-terminal PF4 peptide. Accordingly, PF4 modulates megakaryocyte maturation in vitro, and may function as a negative autocrine regulator of human megakaryocytopoiesis. Images PMID:2523411

A study of professional radiation hazards in CT scan and nuclear medicine workers using GTG-banding and solid stain.

PubMed

Changizi, Vahid; Alizadeh, Mohammad Hossein; Mousavi, Akbar

2015-01-01

CT scan and nuclear medicine exams deliver a great part of medical exposures. This study examined professional radiation hazards in CT scan and nuclear medicine workers. In a cross sectional study 30 occupationally exposed workers and 7 controls (all from personnel of a laboratory) were selected. Physical dosimetry was performed for exposed workers. Blood samples were obtained from the experimental and control groups. Three culture mediums for each one were prepared in due to routine chromosome analysis using G-banding and solid stain. There were significant increased incidence of chromatid gap (ctg) and chromatid break (ctb) with mean±SD frequencies of 3±0.84 and 3.1±1.40 per 100 cells respectively in the nuclear medicine workers versus controls with mean±SD frequencies of 1.9±0.69 and 1.3±0.84 for ctg and ctb, respectively. Chromosome gaps (chrg) were higher significantly in the nuclear medicine population (2.47±0.91) than in controls (1.4±0.9) (p< 0.05). In CT scan group the ctg and ctb were increased with a mean±SD frequency of 2.7±0.79 and 2.6±0.91 per 100 cells respectively compared with control group. The mean±SD frequencies of the chrb were 2.0±0.75 and 0.86±0.690 per 100 cells for exposed workers and control group, respectively. This study showed chromosome aberrations in peripheral lymphocytes using solid stain method are reasonable biomarker reflecting personnel radiation damage.

Correlation of Resistance to Proflavine and Penicillin in Escherichia coli

PubMed Central

McKellar, Robin C.; McKenzie, Colin N.; Kushner, Donn J.

1976-01-01

A number of proflavine (PF)-resistant mutants of Escherichia coli B were also resistant to penicillin and cephalothin. Mutants resistant to 1.0 mM PF were 10 times more penicillin resistant than were the PF-susceptible, wild-type cells. Single-step mutants selected for resistance to either PF or penicillin were also resistant to the other drug. None of the resistant mutants tested possessed β-lactamase activity. These results suggest that resistance to PF and penicillin in E. coli B may be due to permeability changes in the cell envelope. PMID:791110

Hematological and biochemical features of postpartum fever in the heavy draft mare.

PubMed

Aoki, Takahiro; Kimura, Yuki; Oya, Anna; Chiba, Akiko; Ishii, Mitsuo; Nambo, Yasuo

2016-01-01

Heavy draft mares potentially have a higher risk of suffering from postpartum fever (PF) than light breed mares. The purpose of this study was to compare hematological and biochemical features between clinically healthy mares (n=40) and PF-affected mares (n=16). Mares were classified as having PF when their rectal temperature rose to >38.5°C within 96 hr of foaling. The numbers of leukocytes, lymphocytes, and neutrophils and the serum magnesium level were significantly lower in PF-affected mares. The serum SAA and NEFA levels were significantly higher in PF-affected mares. Strong inflammation responses, fat mobilization associated with negative energy balance and possibly endotoxin participate in hematological and biochemical features of PF in heavy draft mares.

Proton-neutron sdg boson model and spherical-deformed phase transition

NASA Astrophysics Data System (ADS)

Otsuka, Takaharu; Sugita, Michiaki

1988-12-01

The spherical-deformed phase transition in nuclei is described in terms of the proton-neutron sdg interacting boson model. The sdg hamiltonian is introduced to model the pairing+quadrupole interaction. The phase transition is reproduced in this framework as a function of the boson number in the Sm isotopes, while all parameters in the hamiltonian are kept constant at values reasonable from the shell-model point of view. The sd IBM is derived from this model through the renormalization of g-boson effects.

Two-cluster structure of some alpha-scattering resonances in the sd shell

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

Budzanowski, A.; Grotowski, K.; Strzalkowski, A.

1975-01-01

The excitation functions of the elastic scattering of alpha particles at backward angles on $sup 24$Mg and $sup 28$Si nuclei in the energy range from 23 to 28 MeV measured by Bobrowska et al. exhibit distinct maxima. It was shown that these maxima are not correlated with the structures seen in the excitation functions of the ($alpha$,$alpha$') and ($alpha$,p) reactions leading to low- lying excited states of the final nucleus possibly indicating the presence of Ericson fluctuations. (auth)

Comment on "Properties of (26)Mg and (26)Si in the sd shell model and the determination of the (25)Al(p,gamma) (26) Si reaction rate"

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

Chipps, K.; Bardayan, Daniel W; Liang, J Felix

2011-01-01

A recent discussion of theoretical work on the {sup 25}Al(p,{gamma}){sup 26}Si astrophysical reaction rate [W.A. Richter, B. Alex Brown, A. Signoracci and M. Wiescher Phys. Rev. C 83 065803 (2011)] omits some current and relevant experimental information in forming its scientific conclusions. Accounting for this new information has the potential to significantly alter the reaction rate derived in the paper.

Population of positive-parity states in {sup 53}Sc through one-proton knockout.

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

McDaniel, S.; Gade, A.; Janssens, R. V. F.

2010-02-01

The one-proton knockout reaction {sup 9}Be({sup 54}Ti,{sup 53}Sc+{gamma})X at 72 MeV/nucleon has been measured. The location of the first 3/2{sup -} state at 2110(3) keV was confirmed, and new {gamma}-ray transitions were observed at 1111(2), 1273(2), 1539(4), and 2495(5) keV. Large spectroscopic strength to excited states in {sup 53}Sc was found and attributed to the knockout of sd-shell protons.

Population of positive-parity states in {sup 53}Sc through one-proton knockout

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

McDaniel, S.; Gade, A.; Brown, B. A.

2010-02-15

The one-proton knockout reaction {sup 9}Be({sup 54}Ti,{sup 53}Sc+{gamma})X at 72 MeV/nucleon has been measured. The location of the first 3/2{sup -} state at 2110(3) keV was confirmed, and new {gamma}-ray transitions were observed at 1111(2), 1273(2), 1539(4), and 2495(5) keV. Large spectroscopic strength to excited states in {sup 53}Sc was found and attributed to the knockout of sd-shell protons.

Band gap variations in ferritin-templated nanocrystals

NASA Astrophysics Data System (ADS)

Colton, John; Erickson, Stephen; Smith, Trevor; Watt, Richard

2014-03-01

Ferritin is a 12 nm diameter protein shell with an 8 nm ``cage'' inside that can be used as a template for nanoparticle formation. The native particle is an iron oxide, ferrihydrite, but can be altered or replaced. We have used optical absorption spectroscopy to study the band gap of the ferrihydrite nanoparticles as they age (and become more crystalline), and as they respond to surface interactions with ions in solution. We will also present results of particle composition variations due to incorporation of oxo-anions into the interior of the nanoparticles and substitution of iron with other metals such as cobalt and manganese.

Patellar maltracking is prevalent among patellofemoral pain subjects with patella alta: an upright, weightbearing MRI study

PubMed Central

Pal, Saikat; Besier, Thor F.; Beaupre, Gary S.; Fredericson, Michael; Delp, Scott L.; Gold, Garry E.

2012-01-01

The purpose of this study is to determine if patellar maltracking is more prevalent among patellofemoral (PF) pain subjects with patella alta compared to subjects with normal patella height. We imaged 37 PF pain and 15 pain free subjects in an open-configuration magnetic resonance imaging scanner while they stood in a weightbearing posture. We measured patella height using the Caton-Deschamps, Blackburne-Peel, Insall-Salvati, Modified Insall-Salvati, and Patellotrochlear indices, and classified the subjects into patella alta and normal patella height groups. We measured patella tilt and bisect offset from oblique-axial plane images, and classified the subjects into maltracking and normal tracking groups. Patellar maltracking was more prevalent among PF pain subjects with patella alta compared to PF pain subjects with normal patella height (two-tailed Fisher’s exact test, p < 0.050). Using the Caton-Deschamps index, 67% (8/12) of PF pain subjects with patella alta were maltrackers, whereas only 16% (4/25) of PF pain subjects with normal patella height were maltrackers. Patellofemoral pain subjects classified as maltrackers displayed a greater patella height compared to the pain free and PF pain subjects classified as normal trackers (two-tailed unpaired t-tests with Bonferroni correction, p < 0.017). This study adds to our understanding of PF pain in two ways - 1) we demonstrate that patellar maltracking is more prevalent in PF pain subjects with patella alta compared to subjects with normal patella height; and 2) we show greater patella height in PF pain subjects compared to pain free subjects using four indices commonly used in clinics. PMID:23165335

The Crystal Structure of PF-8, the DNA Polymerase Accessory Subunit from Kaposi's Sarcoma-Associated Herpesvirus

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

Baltz, Jennifer L.; Filman, David J.; Ciustea, Mihai

2009-12-01

Kaposi's sarcoma-associated herpesvirus is an emerging pathogen whose mechanism of replication is poorly understood. PF-8, the presumed processivity factor of Kaposi's sarcoma-associated herpesvirus DNA polymerase, acts in combination with the catalytic subunit, Pol-8, to synthesize viral DNA. We have solved the crystal structure of residues 1 to 304 of PF-8 at a resolution of 2.8 {angstrom}. This structure reveals that each monomer of PF-8 shares a fold common to processivity factors. Like human cytomegalovirus UL44, PF-8 forms a head-to-head dimer in the form of a C clamp, with its concave face containing a number of basic residues that are predictedmore » to be important for DNA binding. However, there are several differences with related proteins, especially in loops that extend from each monomer into the center of the C clamp and in the loops that connect the two subdomains of each protein, which may be important for determining PF-8's mode of binding to DNA and to Pol-8. Using the crystal structures of PF-8, the herpes simplex virus catalytic subunit, and RB69 bacteriophage DNA polymerase in complex with DNA and initial experiments testing the effects of inhibition of PF-8-stimulated DNA synthesis by peptides derived from Pol-8, we suggest a model for how PF-8 might form a ternary complex with Pol-8 and DNA. The structure and the model suggest interesting similarities and differences in how PF-8 functions relative to structurally similar proteins.« less

Immune complexes formed following the binding of anti–platelet factor 4 (CXCL4) antibodies to CXCL4 stimulate human neutrophil activation and cell adhesion

PubMed Central

Xiao, Zhihua; Visentin, Gian P.; Dayananda, Kannayakanahalli M.

2008-01-01

We tested the possibility that immune complexes formed following platelet factor 4 (PF4/CXCL4) binding to anti-PF4 antibody can stimulate neutrophil activation, similar to previous reports with platelets. Monoclonal Abs against PF4 and IgG from a heparin-induced thrombocytopenia (HIT) patient were applied. We observed that although PF4 or anti-PF4 antibody alone did not alter neutrophil function, costimulation with both reagents resulted in approximately 3-fold increase in cell surface Mac-1 expression, enhanced cell adhesion via L-selectin and CD18 integrins, and degranulation of secondary and tertiary granules. The level of Mac-1 up-regulation peaked at an intermediate PF4 dose, suggesting that functional response varies with antigen-antibody stoichiometry. PF4 binding to neutrophils was blocked by chondroitinase ABC. Cell activation was inhibited by both chondroitinase ABC and anti-CD32/FcγRII blocking mAb, IV.3. Confocal microscopy demonstrated that immune complexes colocalize with CD32a. Studies with HIT IgG demonstrated that neutrophils could be activated in the absence of exogenous heparin. These data, together, show that leukocyte surface chondroitin sulfates promote neutrophil activation by enhancing immune-complex binding to CD32a. Studies with recombinant PF4 suggest a role for arginine 49 in stabilizing PF4-chondroitin binding. Neutrophils activated via this mechanism may contribute to thrombosis and inflammation in patients mounting an immune response to PF4-heparin. PMID:18539895

The impact of combined pulmonary fibrosis and chronic obstructive pulmonary disease on long-term survival after lung cancer surgery.

PubMed

Sekine, Yasuo; Sakairi, Yuichi; Yoshino, Mitsuru; Koh, Eitetsu; Hata, Atsushi; Suzuki, Hidemi; Yoshino, Ichiro

2014-06-01

The purpose of this study was to determine the impact of pulmonary fibrosis (PF) on postoperative complications and on long-term survival after surgical resection in lung cancer patients with chronic obstructive pulmonary disease (COPD). A retrospective chart review was conducted of 380 patients with COPD who had undergone pulmonary resection for lung cancer at the University Hospital between 1990 and 2005. The definition of COPD was a preoperative forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio of less than 70%; PF was defined as obvious bilateral fibrous change in the lower lung fields, confirmed by computed tomography. PF was present in 41 patients (10.8%) with COPD; the remaining 339 patients (89.2%) did not have PF. The preoperative FVC/FEV1 was significantly lower in the group of patients with PF than in the group without (p < 0.05). Acute lung injury and home oxygen therapy were significantly more common in the PF group; however, the 30-day mortality was similar between the groups. The cumulative survival at 3 and 5 years was 53.6 and 36.9%, respectively, in the PF group and 71.4 and 66.1%, respectively, in the non-PF group (p = 0.0009). Increased age, decreased body mass index, advanced pathologic stage, and the existence of PF were identified as independent risk factors for decreased survival. PF is a risk factor for decreased survival after surgical treatment in lung cancer patients with COPD. Georg Thieme Verlag KG Stuttgart · New York.

Pseudomonas protegens Pf-5 causes discoloration and pitting of mushroom caps due to the production of antifungal metabolites.

PubMed

Henkels, Marcella D; Kidarsa, Teresa A; Shaffer, Brenda T; Goebel, Neal C; Burlinson, Peter; Mavrodi, Dmitri V; Bentley, Michael A; Rangel, Lorena I; Davis, Edward W; Thomashow, Linda S; Zabriskie, T Mark; Preston, Gail M; Loper, Joyce E

2014-07-01

Bacteria in the diverse Pseudomonas fluorescens group include rhizosphere inhabitants known for their antifungal metabolite production and biological control of plant disease, such as Pseudomonas protegens Pf-5, and mushroom pathogens, such as Pseudomonas tolaasii. Here, we report that strain Pf-5 causes brown, sunken lesions on peeled caps of the button mushroom (Agaricus bisporus) that resemble brown blotch symptoms caused by P. tolaasii. Strain Pf-5 produces six known antifungal metabolites under the control of the GacS/GacA signal transduction system. A gacA mutant produces none of these metabolites and did not cause lesions on mushroom caps. Mutants deficient in the biosynthesis of the antifungal metabolites 2,4-diacetylphloroglucinol and pyoluteorin caused less-severe symptoms than wild-type Pf-5 on peeled mushroom caps, whereas mutants deficient in the production of lipopeptide orfamide A caused similar symptoms to wild-type Pf-5. Purified pyoluteorin and 2,4-diacetylphloroglucinol mimicked the symptoms caused by Pf-5. Both compounds were isolated from mushroom tissue inoculated with Pf-5, providing direct evidence for their in situ production by the bacterium. Although the lipopeptide tolaasin is responsible for brown blotch of mushroom caused by P. tolaasii, P. protegens Pf-5 caused brown blotch-like symptoms on peeled mushroom caps through a lipopeptide-independent mechanism involving the production of 2,4-diacetylphloroglucinol and pyoluteorin.

Novel mucus-penetrating liposomes as a potential oral drug delivery system: preparation, in vitro characterization, and enhanced cellular uptake

PubMed Central

Li, Xiuying; Chen, Dan; Le, Chaoyi; Zhu, Chunliu; Gan, Yong; Hovgaard, Lars; Yang, Mingshi

2011-01-01

Background The aim of this study was to investigate the intestinal mucus-penetrating properties and intestinal cellular uptake of two types of liposomes modified by Pluronic F127 (PF127). Methods The two types of liposomes, ie, PF127-inlaid liposomes and PF127-adsorbed liposomes, were prepared by a thin-film hydration method followed by extrusion, in which coumarin 6 was loaded as a fluorescence marker. A modified Franz diffusion cell mounted with the intestinal mucus of rats was used to study the diffusion characteristics of the two types of PF127 liposomes. Cell uptake studies were conducted in Caco-2 cells and analyzed using confocal laser scanning microcopy as well as flow cytometry. Results The diffusion efficiency of the two types of PF127-modified liposomes through intestinal rat mucus was 5–7-fold higher than that of unmodified liposomes. Compared with unmodified liposomes, PF127-inlaid liposomes showed significantly higher cellular uptake of courmarin 6. PF127-adsorbed liposomes showed a lower cellular uptake. Moreover, and interestingly, the two types of PF127-modified liposomes showed different cellular uptake mechanisms in Caco-2 cells. Conclusion PF127-inlaid liposomes with improved intestinal mucus-penetrating ability and enhanced cellular uptake might be a potential carrier candidate for oral drug delivery. PMID:22163166

Multi-omics Based Identification of Specific Biochemical Changes Associated With PfKelch13-Mutant Artemisinin-Resistant Plasmodium falciparum.

PubMed

Siddiqui, Ghizal; Srivastava, Anubhav; Russell, Adrian S; Creek, Darren J

2017-05-01

The emergence of artemisinin resistance in the malaria parasite Plasmodium falciparum poses a major threat to the control and elimination of malaria. Certain point mutations in the propeller domain of PfKelch13 are associated with resistance, but PfKelch13 mutations do not always result in clinical resistance. The underlying mechanisms associated with artemisinin resistance are poorly understood, and the impact of PfKelch13 mutations on cellular biochemistry is not defined. This study aimed to identify global biochemical differences between PfKelch13-mutant artemisinin-resistant and -sensitive strains of P. falciparum by combining liquid chromatography-mass spectrometry (LC-MS)-based proteomics, peptidomics, and metabolomics. Proteomics analysis found both PfKelch13 mutations examined to be specifically associated with decreased abundance of PfKelch13 protein. Metabolomics analysis demonstrated accumulation of glutathione and its precursor, gamma-glutamylcysteine, and significant depletion of 1 other putative metabolite in resistant strains. Peptidomics analysis revealed lower abundance of several endogenous peptides derived from hemoglobin (HBα and HBβ) in the artemisinin-resistant strains. PfKelch13 mutations associated with artemisinin resistance lead to decreased abundance of PfKelch13 protein, decreased hemoglobin digestion, and enhanced glutathione production. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Dynamometer-based measure of spasticity confirms limited association between plantarflexor spasticity and walking function in persons with multiple sclerosis

PubMed Central

Kremer, Theodore R.; Van Dillen, Linda R.; Wagner, Joanne M.

2017-01-01

The literature shows inconsistent evidence regarding the association between clinically assessed plantarflexor (PF) spasticity and walking function in ambulatory persons with multiple sclerosis (pwMS). The use of a dynamometer-based spasticity measure (DSM) may help to clarify this association. Our cohort included 42 pwMS (27 female, 15 male; age: 42.9 +/− 10.2 yr) with mild clinical disability (Expanded Disability Status Scale score: 3.6 +/− 1.6). PF spasticity was assessed using a clinical measure, the modified Ashworth Scale (MAS), and an instrumented measure, the DSM. Walking function was assessed by the timed 25-foot walk test (T25FWT), the 6-minute walk test (6MWT), and the 12-item Multiple Sclerosis Walking Scale (MSWS-12). Spearman rho correlations were used to evaluate relationships between spasticity measures, measures of walking speed and endurance, and self-perceived limitations in walking. The correlation was small between PF spasticity and the T25FWT (PF maximum [Max] MAS rho = 0.27, PF Max DSM rho = 0.26), the 6MWT (PF Max MAS rho = −0.20, PF Max DSM rho = −0.21), and the MSWS-12 (PF Max MAS rho = 0.11, PF Max DSM rho = 0.26). Our results are similar to reports in other neurologic clinical populations, wherein spasticity has a limited association with walking dysfunction. PMID:25356797

Development of a copula-based particle filter (CopPF) approach for hydrologic data assimilation under consideration of parameter interdependence

NASA Astrophysics Data System (ADS)

Fan, Y. R.; Huang, G. H.; Baetz, B. W.; Li, Y. P.; Huang, K.

2017-06-01

In this study, a copula-based particle filter (CopPF) approach was developed for sequential hydrological data assimilation by considering parameter correlation structures. In CopPF, multivariate copulas are proposed to reflect parameter interdependence before the resampling procedure with new particles then being sampled from the obtained copulas. Such a process can overcome both particle degeneration and sample impoverishment. The applicability of CopPF is illustrated with three case studies using a two-parameter simplified model and two conceptual hydrologic models. The results for the simplified model indicate that model parameters are highly correlated in the data assimilation process, suggesting a demand for full description of their dependence structure. Synthetic experiments on hydrologic data assimilation indicate that CopPF can rejuvenate particle evolution in large spaces and thus achieve good performances with low sample size scenarios. The applicability of CopPF is further illustrated through two real-case studies. It is shown that, compared with traditional particle filter (PF) and particle Markov chain Monte Carlo (PMCMC) approaches, the proposed method can provide more accurate results for both deterministic and probabilistic prediction with a sample size of 100. Furthermore, the sample size would not significantly influence the performance of CopPF. Also, the copula resampling approach dominates parameter evolution in CopPF, with more than 50% of particles sampled by copulas in most sample size scenarios.

Antibodies associated with heparin-induced thrombocytopenia (HIT) inhibit activated protein C generation: new insights into the prothrombotic nature of HIT.

PubMed

Kowalska, M Anna; Krishnaswamy, Sriram; Rauova, Lubica; Zhai, Li; Hayes, Vincent; Amirikian, Karine; Esko, Jeffrey D; Bougie, Daniel W; Aster, Richard H; Cines, Douglas B; Poncz, Mortimer

2011-09-08

Heparin-induced thrombocytopenia (HIT) is caused by antibodies that recognize complexes between platelet factor 4 (PF4) and heparin or glycosaminoglycan side chains. These antibodies can lead to a limb- and life-threatening prothrombotic state. We now show that HIT antibodies are able to inhibit generation of activated protein C (aPC) by thrombin/thrombomodulin (IIa/TM) in the presence of PF4. Tetrameric PF4 potentiates aPC generation by formation of complexes with chondroitin sulfate (CS) on TM. Formation of these complexes occurs at a specific molar ratio of PF4 to glycosaminoglycan. This observation and the finding that the effect of heparin on aPC generation depends on the concentration of PF4 suggest similarity between PF4/CS complexes and those that bind HIT antibodies. HIT antibodies reduced the ability of PF4 to augment aPC formation. Cationic protamine sulfate, which forms similar complexes with heparin, also enhanced aPC generation, but its activity was not blocked by HIT antibodies. Our studies provide evidence that complexes formed between PF4 and TM's CS may play a physiologic role in potentiating aPC generation. Recognition of these complexes by HIT antibodies reverses the PF4-dependent enhancement in aPC generation and may contribute to the prothrombotic nature of HIT.

Neutralization of Plasmodium falciparum merozoites by antibodies against PfRH5

PubMed Central

Douglas, Alexander D.; Williams, Andrew R.; Knuepfer, Ellen; Illingworth, Joseph J.; Furze, Julie M.; Crosnier, Cécile; Choudhary, Prateek; Bustamante, Leyla Y.; Zakutansky, Sara E.; Awuah, Dennis K.; Alanine, Daniel G. W.; Theron, Michel; Worth, Andrew; Shimkets, Richard; Rayner, Julian C.; Holder, Anthony A.; Wright, Gavin J.; Draper, Simon J.

2013-01-01

There is intense interest in induction and characterization of strain-transcending neutralizing antibody against antigenically variable human pathogens. We have recently identified the human malaria parasite Plasmodium falciparum reticulocyte-binding protein homologue 5 (PfRH5) as a target of broadly-neutralizing antibodies, but there is little information regarding the functional mechanism(s) of antibody-mediated neutralization. Here, we report that vaccine-induced polyclonal anti-PfRH5 antibodies inhibit the tight attachment of merozoites to erythrocytes, and are capable of blocking the interaction of PfRH5 with its receptor basigin. Furthermore, by developing anti-PfRH5 monoclonal antibodies (mAbs), we provide evidence that i) the ability to block the PfRH5-basigin interaction in vitro is predictive of functional activity, but absence of blockade does not predict absence of functional activity; ii) neutralizing mAbs bind spatially-related epitopes on the folded protein, involving at least two defined regions of the PfRH5 primary sequence; iii) a brief exposure window of PfRH5 is likely to necessitate rapid binding of antibody to neutralize parasites; and iv) intact bivalent IgG contributes to but is not necessary for parasite neutralization. These data provide important insight into the mechanisms of broadly-neutralizing anti-malaria antibodies and further encourage anti-PfRH5 based malaria prevention efforts. PMID:24293631

Structure and anticoagulant property of a sulfated polysaccharide isolated from the green seaweed Monostroma angicava.

PubMed

Li, Na; Liu, Xue; He, Xiaoxi; Wang, Shuyao; Cao, Sujian; Xia, Zheng; Xian, Huali; Qin, Ling; Mao, Wenjun

2017-03-01

An anticoagulant-active polysaccharide PF2 was extracted with boiling water from the green seaweed Monostroma angicava, further purified by anion-exchange and size-exclusion chromatography. PF2 was a rhamnan-type sulfated polysaccharide with molecular weight of about 88.1kDa. Results of chemical and spectroscopic analyses demonstrated that PF2 consisted of→3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→residues, with partially branches at C-2 of→3)-α-l-Rhap-(1→residues. Sulfate groups were substituted at C-3 of →2)-α-l-Rhap-(1→ residues. The sulfated polysaccharide PF2 had a high anticoagulant action, and the mechanism of anticoagulant activity mediated by PF2 was mainly attributed to strong potentiation thrombin by heparin cofactor II. PF2 also exhibited weak effect on antithrombin-dependent thrombin or factor Xa inhibition. The fibrin(ogen)olytic activity and thrombolytic activity of PF2 were also evaluated. The investigation revealed that PF2 was a novel sulfated rhamnan differing from previously described sulfated polysaccharides from green seaweed and could be a potential anticoagulant polysaccharide. Copyright © 2016 Elsevier Ltd. All rights reserved.

Paeoniflorin protects against ischemia-induced brain damages in rats via inhibiting MAPKs/NF-κB-mediated inflammatory responses.

PubMed

Guo, Ruo-Bing; Wang, Guo-Feng; Zhao, An-Peng; Gu, Jun; Sun, Xiu-Lan; Hu, Gang

2012-01-01

Paeoniflorin (PF), the principal component of Paeoniae Radix prescribed in traditional Chinese medicine, has been reported to exhibit many pharmacological effects including protection against ischemic injury. However, the mechanisms underlying the protective effects of PF on cerebral ischemia are still under investigation. The present study showed that PF treatment for 14 days could significantly inhibit transient middle cerebral artery occlusion (MCAO)-induced over-activation of astrocytes and microglia, and prevented up-regulations of pro-inflamamtory mediators (TNFα, IL-1β, iNOS, COX(2) and 5-LOX) in plasma and brain. Further study demonstrated that chronic treatment with PF suppressed the activations of JNK and p38 MAPK, but enhanced ERK activation. And PF could reverse ischemia-induced activation of NF-κB signaling pathway. Moreover, our in vitro study revealed that PF treatment protected against TNFα-induced cell apoptosis and neuronal loss. Taken together, the present study demonstrates that PF produces a delayed protection in the ischemia-injured rats via inhibiting MAPKs/NF-κB mediated peripheral and cerebral inflammatory response. Our study reveals that PF might be a potential neuroprotective agent for stroke.

Massive remobilization of permafrost carbon during post-glacial warming

PubMed Central

Tesi, T.; Muschitiello, F.; Smittenberg, R. H.; Jakobsson, M.; Vonk, J. E.; Hill, P.; Andersson, A.; Kirchner, N.; Noormets, R.; Dudarev, O.; Semiletov, I.; Gustafsson, Ö

2016-01-01

Recent hypotheses, based on atmospheric records and models, suggest that permafrost carbon (PF-C) accumulated during the last glaciation may have been an important source for the atmospheric CO2 rise during post-glacial warming. However, direct physical indications for such PF-C release have so far been absent. Here we use the Laptev Sea (Arctic Ocean) as an archive to investigate PF-C destabilization during the last glacial–interglacial period. Our results show evidence for massive supply of PF-C from Siberian soils as a result of severe active layer deepening in response to the warming. Thawing of PF-C must also have brought about an enhanced organic matter respiration and, thus, these findings suggest that PF-C may indeed have been an important source of CO2 across the extensive permafrost domain. The results challenge current paradigms on the post-glacial CO2 rise and, at the same time, serve as a harbinger for possible consequences of the present-day warming of PF-C soils. PMID:27897191

Massive remobilization of permafrost carbon during post-glacial warming

NASA Astrophysics Data System (ADS)

Tesi, T.; Muschitiello, F.; Smittenberg, R. H.; Jakobsson, M.; Vonk, J. E.; Hill, P.; Andersson, A.; Kirchner, N.; Noormets, R.; Dudarev, O.; Semiletov, I.; Gustafsson, Ö.

2016-11-01

Recent hypotheses, based on atmospheric records and models, suggest that permafrost carbon (PF-C) accumulated during the last glaciation may have been an important source for the atmospheric CO2 rise during post-glacial warming. However, direct physical indications for such PF-C release have so far been absent. Here we use the Laptev Sea (Arctic Ocean) as an archive to investigate PF-C destabilization during the last glacial-interglacial period. Our results show evidence for massive supply of PF-C from Siberian soils as a result of severe active layer deepening in response to the warming. Thawing of PF-C must also have brought about an enhanced organic matter respiration and, thus, these findings suggest that PF-C may indeed have been an important source of CO2 across the extensive permafrost domain. The results challenge current paradigms on the post-glacial CO2 rise and, at the same time, serve as a harbinger for possible consequences of the present-day warming of PF-C soils.

Evidence of C-F-P and aromatic π-F-P weak interactions in imidazolium ionic liquids and its consequences

NASA Astrophysics Data System (ADS)

Panja, Sumit Kumar; Srivastava, Nitin; Srivastava, Jyoti; Prasad, Namburi Eswara; Noothalapati, Hemanth; Shigeto, Shinsuke; Saha, Satyen

2018-04-01

A simple change from alkyl group to alkene in side chain of imidazolium cation with same anion resulted in a drastic impact on physical properties (e.g., melting point) from bmimPF6 IL to cmimPF6 IL. The underlying reasons have been elucidated by structural and interaction studies with the help of DSC, SCXRD, vibrational and multi-nuclear NMR spectroscopic techniques. Experiments reveal existence of new weak interactions involving the carbon and π cloud of the imidazolium aromatic ring with fluoride of PF6 anion (i.e., C2-F-P and π-F-P) in cmimPF6 but are absent in structurally similar prototype IL, bmimPF6. Though weak, these interactions helped to form ladder type supramolecular arrangement, resulting in quite high melting point for cmimPF6 IL compared to bmimPF6 IL. These findings emphasize that an IL system can behave uniquely because of the existence of uncommon weak interactions.

About PF

MedlinePlus

... vapors that can cause PF (such as asbestos, coal, silica, and others) Some MEDICATIONS can cause PF. ... wide variety of inorganic dusts, including asbestos, silica, coal dust, beryllium, and hard metal dusts. Are there ...

Pfhrp2 and pfhrp3 polymorphisms in Plasmodium falciparum isolates from Dakar, Senegal: impact on rapid malaria diagnostic tests

PubMed Central

2013-01-01

Background An accurate diagnosis is essential for the rapid and appropriate treatment of malaria. The accuracy of the histidine-rich protein 2 (PfHRP2)-based rapid diagnostic test (RDT) Palutop+4® was assessed here. One possible factor contributing to the failure to detect malaria by this test is the diversity of the parasite PfHRP2 antigens. Methods PfHRP2 detection with the Palutop+4® RDT was carried out. The pfhrp2 and pfhrp3 genes were amplified and sequenced from 136 isolates of Plasmodium falciparum that were collected in Dakar, Senegal from 2009 to 2011. The DNA sequences were determined and statistical analyses of the variation observed between these two genes were conducted. The potential impact of PfHRP2 and PfHRP3 sequence variation on malaria diagnosis was examined. Results Seven P. falciparum isolates (5.9% of the total isolates, regardless of the parasitaemia; 10.7% of the isolates with parasitaemia ≤0.005% or ≤250 parasites/μl) were undetected by the PfHRP2 Palutop+4® RDT. Low parasite density is not sufficient to explain the PfHRP2 detection failure. Three of these seven samples showed pfhrp2 deletion (2.4%). The pfhrp3 gene was deleted in 12.8%. Of the 122 PfHRP2 sequences, 120 unique sequences were identified. Of the 109 PfHRP3 sequences, 64 unique sequences were identified. Using the Baker’s regression model, at least 7.4% of the P. falciparum isolates in Dakar were likely to be undetected by PfHRP2 at a parasite density of ≤250 parasites/μl (slightly lower than the evaluated prevalence of 10.7%). This predictive prevalence increased significantly between 2009 and 2011 (P = 0.0046). Conclusion In the present work, 10.7% of the isolates with a parasitaemia ≤0.005% (≤250 parasites/μl) were undetected by the PfHRP2 Palutop+4® RDT (7.4% by the predictive Baker’model). In addition, all of the parasites with pfhrp2 deletion (2.4% of the total samples) and 2.1% of the parasites with parasitaemia >0.005% and presence of pfhrp2 were not detected by PfHRP2 RDT. PfHRP2 is highly polymorphic in Senegal. Efforts should be made to more accurately determine the prevalence of non-sensitive parasites to pfHRP2. PMID:23347727

Temporal and Spatial Patterns of Preferential Flow Occurrence in the Shale Hills Catchment: From the Hillslope to the Catchment Scales

NASA Astrophysics Data System (ADS)

Liu, H.; Lin, H.

2013-12-01

Understanding temporal and spatial patterns of preferential flow (PF) occurrence is important in revealing hillslope and catchment hydrologic and biogeochemical processes. Quantitative assessment of the frequency and control of PF occurrence in the field, however, has been limited, especially at the landscape scale of hillslope and catchment. By using 5.5-years' (2007-2012) real-time soil moisture at 10 sites response to 323 precipitation events, we tested the temporal consistency of PF occurrence at the hillslope scale in the forested Shale Hills Catchment; and by using 25 additional sites with at least 1-year data (2011-2012), we evaluated the spatial patterns of PF occurrence across the catchment. To explore the potential effects of PF occurrence on catchment hydrology, wavelet analysis was performed on the recorded time series of hydrological signals (i.e., precipitation, soil moisture, catchment discharge). Considerable temporal consistence was observed in both the frequency and the main controls of PF occurrence at the hillslope scale, which was attributed largely to the statistical stability of precipitation pattern over the monitoring period and the relatively stable subsurface preferential pathways. Preferential flow tended to occur more often in response to intense rainfall events, and favored the conditions at dry hilltop or wet valley floor sites. When upscaling to the entire catchment, topographic control on the PF occurrence was amplified remarkably, leading to the identification of a subsurface PF network in the catchment. Higher frequency of PF occurrence was observed at the valley floor (average 48%), hilltop (average 46%), and swales/hillslopes near the stream (average 40%), while the hillslopes in the eastern part of the catchment were least likely to experience PF (0-20%). No clear relationship, however, was observed between terrain attributes and PF occurrence, because the initiation and persistency of PF in this catchment was controlled jointly by complex interactions among landform units, soil types, initial soil moisture, precipitation features, and season. Through the wavelet method (coherence spectrum and phase differences), dual-pore filtering effects of soil system were proven, rendering it possible to further infer characteristic properties of the underlying hydrological processes in the subsurface. We found that preferential flow dominates the catchment discharge response at short-time periods (< 3 days), while the matrix flow may dominate the discharge response at the time scales of around 10-12 days. The temporal and spatial patterns of PF occurrence revealed in this study can help advance the modeling and prediction of complex PF dynamics in this and other similar landscapes.

Off-shell hydrodynamics from holography

DOE PAGES

Crossley, Michael; Glorioso, Paolo; Liu, Hong; ...

2016-02-18

In this article, we outline a program for obtaining an action principle for dissipative fluid dynamics by considering the holographic Wilsonian renormalization group applied to systems with a gravity dual. As a first step, in this paper we restrict to systems with a non-dissipative horizon. By integrating out gapped degrees of freedom in the bulk gravitational system between an asymptotic boundary and a horizon, we are led to a formulation of hydrodynamics where the dynamical variables are not standard velocity and temperature fields, but the relative embedding of the boundary and horizon hypersurfaces. At zeroth order, this action reduces tomore » that proposed by Dubovsky et al. as an off-shell formulation of ideal fluid dynamics.« less

Small size yet big action: a simple sulfate anion templated a discrete 78-nuclearity silver sulfur nanocluster with a multishell structure.

PubMed

Cheng, Li-Ping; Wang, Zhi; Wu, Qiao-Yu; Su, Hai-Feng; Peng, Tao; Luo, Geng-Geng; Li, Yan-An; Sun, Di; Zheng, Lan-Sun

2018-03-07

A discrete 78-nucleus silver-sulfur nanocluster with a sulfate-centered multishell structure was isolated and characterized. Its crystal structure revealed 18 and 60 Ag atoms in the inner and outer shell, respectively. The inner shell of 18-nuclearity Ag atoms is a very rare convex polyhedron featuring an elongated triangular orthobicupola. The incorporation of a sulfate anion and multishell arrangement in the nanocluster led to a dramatic decrease in the band gap (E g = 1.40 eV). Our study showed that simple anions can also induce the formation of high-nuclearity silver clusters with excellent optical properties.

Black GE based on crystalline/amorphous core/shell nanoneedle arrays

DOEpatents

Javey, Ali; Chueh, Yu-Lun; Fan, Zhiyong

2014-03-04

Direct growth of black Ge on low-temperature substrates, including plastics and rubber is reported. The material is based on highly dense, crystalline/amorphous core/shell Ge nanoneedle arrays with ultrasharp tips (.about.4 nm) enabled by the Ni catalyzed vapor-solid-solid growth process. Ge nanoneedle arrays exhibit remarkable optical properties. Specifically, minimal optical reflectance (<1%) is observed, even for high angles of incidence (.about.75.degree.) and for relatively short nanoneedle lengths (.about.1 .mu.m). Furthermore, the material exhibits high optical absorption efficiency with an effective band gap of .about.1 eV. The reported black Ge can have important practical implications for efficient photovoltaic and photodetector applications on nonconventional substrates.

Metal complexes of fluorophosphines. 13. Reaction of fac-(CH/sub 3/CN)/sub 3/Mo(CO)/sub 3/ with (methylamino)bis(difluorophosphine). X-ray crystal structure analysis of a novel binuclear molybdenum fluorophosphine carbonyl complex with a bridging chlorine atom: (CO)/sub 2/Mo(/sup +/-CH/sub 3/N(PF/sub 2/)/sub 2/)/sub 2/(. mu. -PF/sub 2/)(. mu. -Cl)Mo(CO)(PF/sub 2/NHCH/sub 3/)

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

King, R.B.; Shimura, M.; Brown, G.M.

1984-01-01

Reaction of fac-(CH/sub 3/CN)/sub 3/Mo(CO)/sub 3/ with CH/sub 3/N(PF/sub 2/)/sub 2/ in acetonitrile solution at room temperature gives white, volatile, crystalline fac-(CH/sub 3/N(PF/sub 2/)/sub 2/)/sub 2/Mo(CO)/sub 3/, containing one monodentate and one bidentate CH/sub 3/N(PF/sub 2/)/sub 2/ ligand. The same reactants in boiling acetonitrile give yellow (CH/sub 3/N(PF/sub 2/)/sub 2/)/sub 4/Mo/sub 2/(CO)/sub 3/ in considerably better yield than the previously reported preparation of this binuclear complex from the cycloheptatriene complex C/sub 7/H/sub 8/Mo(CO)/sub 3/ and CH/sub 3/N(PF/sub 2/)/sub 2/ in boiling methylcyclohexane. Reaction in acetonitrile solution of fac-(CH/sub 3/CN)/sub 3/Mo(CO)/sub 3/ with CH/sub 3/N(PF/sub 2/)/sub 2/ containing about 0.2% HClmore » gives brown-red, volatile (CO)/sub 2/Mo(/sup +/-CH/sub 3/N(PF/sub 2/)/sub 2/)/sub 2/(..mu..-PF/sub 2/)(..mu..-Cl)-Mo(CO)(PF/sub 2/NHCH/sub 3/), whose composition and structure were established by single-crystal X-ray structure analysis. This novel quadruply bridged binuclear complex is obtained in considerably better yield from the reaction of (CH/sub 3/N(PF/sub 2/)/sub 2/)/sub 3/Mo/sub 2/(CO)/sub 5/ with ((C/sub 2/H/sub 5/)/sub 3/NH)Cl in acetonitirle solution. The complex has a Mo-Mo bond 2.975 A in length. Crystal data: monoclinic, space group P2/sub 1//c, a = 17.546 (4) A, b = 9.725 (2) A, c = 14.558 (3), ..beta.. = 107.20 (2)/sup 0/, Z = 4. 30 references, 2 figures, 3 tables.« less

Resting State and Elementary Steps of the Coupling of Aryl Halides with Thiols Catalyzed by Alkylbisphosphine Complexes of Palladium

PubMed Central

Alvaro, Elsa

2010-01-01

Detailed mechanistic studies on the coupling of aryl halides with thiols catalyzed by palladium complexes of the alkylbisphosphine ligand CyPF-tBu (1-dicyclohexylphosphino-2-di-tert-butylphosphinoethylferrocene) are reported. The elementary steps that constitute the catalytic cycle, i.e. oxidative addition, transmetalation and reductive elimination, have been studied, and their relative rates are reported. Each of the steps of the catalytic process occurs at temperatures that are much lower than those required for the reactions catalyzed by a combination of palladium precursors and CyPF-tBu. To explain these differences in rates between the catalytic and stoichiometric reactions, studies were conducted to identify the resting state of the catalyst of the reactions catalyzed by a combination of Pd(OAc)2 and CyPF-tBu, a combination of Pd(dba)2 and CyPF-tBu, or the likely intermediate Pd(CyPF-tBu)(Ar)(Br). These show that the major palladium complex in each case lies off of the catalytic cycle. The resting state of the reactions catalyzed by Pd(OAc)2 and CyPF-tBu was the palladium bis-thiolate complex [Pd(CyPF-tBu)(SR)2] (R = alkyl or aryl). The resting state in reactions catalyzed by Pd2(dba)3 and CyPF-tBu was the binuclear complex [Pd(CyPF-tBu)]2(μ2, η2-dba) (9). The resting state of reactions of both aromatic and aliphatic thiols catalyzed by [Pd(CyPF-tBu)(p-tolyl)(Br)] (3a) was the hydridopalladium thiolate complex [Pd(CyPF-tBu)(H)(SR)] (R= alkyl and aryl). All these palladium species have been prepared independently, and the mechanisms by which they enter the catalytic cycle have been examined in detail. These features of the reaction catalyzed by palladium and CyPF-tBu have been compared with those of reactions catalyzed by the alkylbisphosphine DiPPF and Pd(OAc)2 or Pd(dba)2. Our data indicate that the resting states of these reactions are similar to each other and that our mechanistic conclusions about reactions catalyzed by palladium and CyPF-tBu can be extrapolated to reactions catalyzed by complexes of other electron-rich bisphosphines. PMID:19453106

Influence of central metalloligand geometry on electronic communication between metals: syntheses, crystal structures, MMCT properties of isomeric cyanido-bridged Fe2Ru complexes, and TDDFT calculations.

PubMed

Ma, Xiao; Lin, Chen-Sheng; Hu, Sheng-Min; Tan, Chun-Hong; Wen, Yue-Hong; Sheng, Tian-Lu; Wu, Xin-Tao

2014-06-02

To investigate how the central metalloligand geometry influences distant or vicinal metal-to-metal charge-transfer (MMCT) properties of polynuclear complexes, cis- and trans-isomeric heterotrimetallic complexes, and their one- and two-electron oxidation products, cis/trans-[Cp(dppe)Fe(II)NCRu(II)(phen)2CN-Fe(II)(dppe)Cp][PF6]2 (cis/trans-1[PF6]2), cis/trans-[Cp(dppe)Fe(II)NCRu(II)(phen)2CNFe(III)-(dppe)Cp][PF6]3 (cis/trans-1[PF6]3) and cis/trans-[Cp(dppe)Fe(III)NCRu(II)(phen)2CN-Fe(III)(dppe)Cp][PF6]4 (cis/trans-1[PF6]4) have been synthesized and characterized. Electrochemical measurements show the presence of electronic interactions between the two external Fe(II) atoms of the cis- and trans-isomeric complexes cis/trans-1[PF6]2. The electronic properties of all these complexes were studied and compared by spectroscopic techniques and TDDFT//DFT calculations. As expected, both mixed valence complexes cis/trans-1[PF6]3 exhibited different strong absorption signals in the NIR region, which should mainly be attributed to a transition from an MO that is delocalized over the Ru(II)-CN-Fe(II) subunit to a Fe(III) d orbital with some contributions from the co-ligands. Moreover, the NIR transition energy in trans-1[PF6]3 is lower than that in cis-1[PF6]3, which is related to the symmetry of their molecular orbitals on the basis of the molecular orbital analysis. Also, the electronic spectra of the two-electron oxidized complexes show that trans-1[PF6]4 possesses lower vicinal Ru(II) → Fe(III) MMCT transition energy than cis-1[PF6]4. Moreover, the assignment of MMCT transition of the oxidized products and the differences of the electronic properties between the cis and trans complexes can be well rationalized using TDDFT//DFT calculations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phosphorylation Determines the Calmodulin-mediated Ca2+ Response and Water Permeability of AQP0*

PubMed Central

Kalman, Katalin; Németh-Cahalan, Karin L.; Froger, Alexandrine; Hall, James E.

2008-01-01

In Xenopus oocytes, the water permeability of AQP0 (Pf) increases with removal of external calcium, an effect that is mediated by cytoplasmic calmodulin (CaM) bound to the C terminus of AQP0. To investigate the effects of serine phosphorylation on CaM-mediated Ca2+ regulation of Pf, we tested the effects of kinase activation, CaM inhibition, and a series of mutations in the C terminus CaM binding site. Calcium regulation of AQP0 Pf manifests four distinct phenotypes: Group 1, with high Pf upon removal of external Ca2+ (wild-type, S229N, R233A, S235A, S235K, K238A, and R241E); Group 2, with high Pf in elevated (5 mm) external Ca2+ (S235D and R241A); Group 3, with high Pf and no Ca2+ regulation (S229D, S231N, S231D, S235N, and S235N/I236S); and Group 4, with low Pf and no Ca2+ regulation (protein kinase A and protein kinase C activators, S229D/S235D and S235N/I236S). Within each group, we tested whether CaM binding mediates the phenotype, as shown previously for wild-type AQP0. In the presence of calmidazolium, a CaM inhibitor, S235D showed high Pf and no Ca2+ regulation, suggesting that S235D still binds CaM. Contrarily, S229D showed a decrease in recruitment of CaM, suggesting that S229D is unable to bind CaM. Taken together, our results suggest a model in which CaM acts as an inhibitor of AQP0 Pf. CaM binding is associated with a low Pf state, and a lack of CaM binding is associated with a high Pf state. Pathological conditions of inappropriate phosphorylation or calcium/CaM regulation could induce Pf changes contributing to the development of a cataract. PMID:18508773

Identification of Plasmodium falciparum reticulocyte binding protein homologue 5-interacting protein, PfRipr, as a highly conserved blood-stage malaria vaccine candidate.

PubMed

Ntege, Edward H; Arisue, Nobuko; Ito, Daisuke; Hasegawa, Tomoyuki; Palacpac, Nirianne M Q; Egwang, Thomas G; Horii, Toshihiro; Takashima, Eizo; Tsuboi, Takafumi

2016-11-04

Genetic variability in Plasmodium falciparum malaria parasites hampers current malaria vaccine development efforts. Here, we hypothesize that to address the impact of genetic variability on vaccine efficacy in clinical trials, conserved antigen targets should be selected to achieve robust host immunity across multiple falciparum strains. Therefore, suitable vaccine antigens should be assessed for levels of polymorphism and genetic diversity. Using a total of one hundred and two clinical isolates from a region of high malaria transmission in Uganda, we analyzed extent of polymorphism and genetic diversity in four recently reported novel blood-stage malaria vaccine candidate proteins: Rh5 interacting protein (PfRipr), GPI anchored micronemal antigen (PfGAMA), rhoptry-associated leucine zipper-like protein 1 (PfRALP1) and Duffy binding-like merozoite surface protein 1 (PfMSPDBL1). In addition, utilizing the wheat germ cell-free system, we expressed recombinant proteins for the four candidates based on P. falciparum laboratory strain 3D7 sequences, immunized rabbits to obtain specific antibodies (Abs) and performed functional growth inhibition assay (GIA). The GIA activity of the raised Abs was demonstrated using both homologous 3D7 and heterologous FVO strains in vitro. Both pfripr and pfralp1 are less polymorphic but the latter is comparatively more diverse, with varied number of regions having insertions and deletions, asparagine and 6-mer repeats in the coding sequences. Pfgama and pfmspdbl1 are polymorphic and genetically diverse among the isolates with antibodies against the 3D7-based recombinant PfGAMA and PfMSPDBL1 inhibiting merozoite invasion only in the 3D7 but not FVO strain. Moreover, although Abs against the 3D7-based recombinant PfRipr and PfRALP1 proteins potently inhibited merozoite invasion of both 3D7 and FVO, the GIA activity of anti-PfRipr was much higher than that of anti-PfRALP1. Thus, PfRipr is regarded as a promising blood-stage vaccine candidate for next-generation vaccines against P. falciparum. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Opalescence(®) bleaching gels on the elution of bulk-fill composite components.

PubMed

Schuster, Lena; Reichl, Franz-Xaver; Rothmund, Lena; He, Xiuli; Yang, Yang; Van Landuyt, Kirsten L; Kehe, Kai; Polydorou, Olga; Hickel, Reinhard; Högg, Christof

2016-02-01

Bleaching treatments can affect release of components from conventional composites. In this continuing study the influence of two different bleaching gels on the elution of bulk-fill composite components was investigated. The composites Tetric EvoCeram(®) Bulk Fill, QuiXFil™ and X-tra fil were treated with the bleaching gels Opalescence PF 15% (PF 15%) for 5 h and PF 35% (PF 35%) for 30 min and then stored in methanol and water for 24 h and 7 d. The eluates were analyzed by gas chromatography/mass spectrometry (GC/MS). Unbleached specimens were used as control group. A total of 7 different elutable substances have been identified from the investigated composites after bleaching-treatment. Three of them were methacrylates: 2-hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA) and trimethylolpropane trimethacrylate (TMPTMA). Compared to the unbleached controls an increase in elution after PF 15%-treatment of following compounds was found: HEMA (Tetric EvoCeram(®) Bulk Fill), TEGDMA (QuiXFil™, X-tra fil) and 4-N,N-dimethylaminobenzoic acid butyl ethoxy ester (DMABEE) (Tetric EvoCeram(®) Bulk Fill, QuiXFil™, X-tra fil). Following compounds showed a reduction in elution after PF 35%-treatment compared to controls: TEGDMA (QuiXFil™) and DMABEE (Tetric EvoCeram(®) Bulk Fill). The highest concentration of HEMA was 0.22 mmol/l (Tetric EvoCeram(®) Bulk Fill, methanol, 7 d, PF 15%), the highest concentration of TEGDMA was 0.3 mmol/l (X-tra fil, water, 7 d, PF 15%) and the highest concentration of DMABEE was 0.05 mmol/l (QuiXFil™, water, 7 d, PF 35%). PF 15% and PF 35% can lead to reduced and/or increased elution of some bulk-fill components, compared to unbleached bulk-fill composites. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

An infrared and Raman study of the reorientational motions and phase transition in and structure of CsPF6

NASA Astrophysics Data System (ADS)

Heyns, Anton M.; de Waal, Danita

1992-12-01

CsPF6I is face-centered cubic and the PF6- ions are randomly distributed among the six equivalent orientations in the crystal. The ions librate in equilibrium positions for an average time τ, and also jump from one orientation to another in a time which is much shorter than τ. The six different orientations in CsPF6I are of much lower symmetry than the full molecular one. The full vibrational spectra of CsPF6 are reported over the temperature range of 300-4 K and can be analyzed in Phase I in terms of (Oh,C¯4v) where C¯4v denotes the symmetry of the ion and Oh that of the site symmetry S. The polarized Raman spectra of single crystals of CsPF6I are interpreted in terms of all the different orientations of the PF6- ions and excellent agreement is obtained between predicted and experimental results. At 90 K CsPF6 undergoes a phase transition and a crystal structure of P4/nmm-D4h7 is assigned to Phase II. This transition is of the second order and shows behavior which corresponds to those of critical phenomena. An order parameter ξ is defined and a critical constant β is calculated to be equal to 0.3. In CsPF6II two orientations of the PF6- ions exist, both conforming to 4mm-C4v symmetry and the disorder persisting in this phase causes the splitting of the vibrational bands to be fully resolved below 60 K only. An activation energy of ˜3.0 kJ/mol is calculated for the motions of the PF6- ions between 90 and 60 K from the variation of the linewidths and intensities of vibrational bands.

Insights into the epidemiological link between biting flies and pemphigus foliaceus in southeastern Brazil.

PubMed

Vernal, Sebastian; Pepinelli, Mateus; Casanova, Claudio; Goulart, Thais M; Kim, Olivia; De Paula, Natalia A; Pinto, Mara C; Sá-Nunes, Anderson; Roselino, Ana Maria

2017-12-01

Black fly and sandfly bites are related to the endemicity of pemphigus foliaceus (PF); however, an immune reaction against the salivary proteins from these flies still requires confirmation in the case of PF patients living in southeastern Brazil. To georeference the distribution of Simuliidae (Diptera: Simuliidae) and Phlebotominae (Diptera: Psychodidae) and of PF cases in the northeastern region of São Paulo State, and to assess the humoral immune response against salivary gland extracts (SGEs) from biting flies in PF patients, relatives, and neighbours. PF patients' medical information recorded between 1965 and 2014 were obtained from the database of the University Hospital. Data on the distribution of fly species were collected from scientific reports and epidemiological databases. Spatial maps relating the distribution of biting flies with PF cases were plotted. Serum IgG antibodies against the SGEs from Simulium nigrimanum, Nyssomyia neivai, and Aedes aegypti (as control) were determined by ELISA. Two hundred and eighty-five PF cases were distributed in 60 municipalities with a prevalence of 57.5 per million inhabitants, revealing well-defined geographical clusters. S. nigrimanum and N. neivai specimens were registered in eight (13.3%) and 26 (43.3%) of these municipalities, respectively. PF patients, and their relatives presented higher levels of IgG against the SGEs of S. nigrimanum and N. neivai (P<0.001 for both), but not against the SGE from A. aegypti (P=0.115 and P=0.552, respectively), as compared to controls. IgG against the SGEs from S. nigrimanum and N. neivai but not against the SGE from A. aegypti correlated with levels of anti-Desmoglein 1 in PF patients (r=0.3848, P=0.039; and r=0.416, P=0.022, respectively). An epidemiological link between biting flies and PF in southeastern Brazil is proposed, implying a possible role of the salivary proteins from these flies in PF etiopathogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

Modifications of Geometric Truncation of the Scattering Phase Function

NASA Astrophysics Data System (ADS)

Radkevich, A.

2017-12-01

Phase function (PF) of light scattering on large atmospheric particles has very strong peak in forward direction constituting a challenge for accurate numerical calculations of radiance. Such accurate (and fast) evaluations are important in the problems of remote sensing of the atmosphere. Scaling transformation replaces original PF with a sum of the delta function and a new regular smooth PF. A number of methods to construct such a PF were suggested. Delta-M and delta-fit methods require evaluation of the PF moments which imposes a numerical problem if strongly anisotropic PF is given as a function of angle. Geometric truncation keeps the original PF unchanged outside the forward peak cone replacing it with a constant within the cone. This approach is designed to preserve the asymmetry parameter. It has two disadvantages: 1) PF has discontinuity at the cone; 2) the choice of the cone is subjective, no recommendations were provided on the choice of the truncation angle. This choice affects both truncation fraction and the value of the phase function within the forward cone. Both issues are addressed in this study. A simple functional form of the replacement PF is suggested. This functional form allows for a number of modifications. This study consider 3 versions providing continuous PF. The considered modifications also bear either of three properties: preserve asymmetry parameter, provide continuity of the 1st derivative of the PF, and preserve mean scattering angle. The second problem mentioned above is addressed with a heuristic approach providing unambiguous criterion of selection of the truncation angle. The approach showed good performance on liquid water and ice clouds with different particle size distributions. Suggested modifications were tested on different cloud PFs using both discrete ordinates and Monte Carlo methods. It was showed that the modifications provide better accuracy of the radiance computation compare to the original geometric truncation.

Penile fracture epidemiology, diagnosis and management in Iran: a narrative review

PubMed Central

Mirzazadeh, Majid; Fallahkarkan, Morteza

2017-01-01

Penile fracture (PF) is considered an emergency in urology. In the literature there are some case series reporting considerable incidence of PF in some parts of Iran. There are no accurate data about the incidence of PF all around Iran. Although it may be uncommon in other parts of the country and in the other countries, it can also be underreported. There are some challenges in diagnosis, management, and also reporting of these cases. In this review of Iranian medical literature, we searched for penile fracture and penile injury keywords in Medline, Scopus, SID, Google and Persian medical journals. We reviewed the status of epidemiology, etiology, diagnosis, management and complications of PF in different parts of Iran in the published literature. To collect more accurate data, we also performed a questionnaire-based study with sending questionnaires by emails to 700 urologists throughout the country with 14% response rate. Incidence of PF varies significantly in different parts of Iran. Western province of Kermanshah has a significantly higher rate of PF. Adding data from different regions of Iran, we calculated that incidence of PF in Iran can be estimated between 1.14 to 10.48 per 100,000 of male populations, most probably closer to lower end. Although the incidence of PF varies significantly in different geographical areas, urologists practicing in Iran on average may encounter a PF patient every 3.5 months. To diagnose PF, majority of reviewed studies relied on history and clinical examination and did not recommend imaging except in patients with possible urethral injuries. Immediate surgical intervention can make good functional results with low morbidity and short hospital stay. Delayed surgical intervention and observational management approaches need large population studies with long term follow up. PMID:28540222

Penile fracture epidemiology, diagnosis and management in Iran: a narrative review.

PubMed

Mirzazadeh, Majid; Fallahkarkan, Morteza; Hosseini, Jalil

2017-04-01

Penile fracture (PF) is considered an emergency in urology. In the literature there are some case series reporting considerable incidence of PF in some parts of Iran. There are no accurate data about the incidence of PF all around Iran. Although it may be uncommon in other parts of the country and in the other countries, it can also be underreported. There are some challenges in diagnosis, management, and also reporting of these cases. In this review of Iranian medical literature, we searched for penile fracture and penile injury keywords in Medline, Scopus, SID, Google and Persian medical journals. We reviewed the status of epidemiology, etiology, diagnosis, management and complications of PF in different parts of Iran in the published literature. To collect more accurate data, we also performed a questionnaire-based study with sending questionnaires by emails to 700 urologists throughout the country with 14% response rate. Incidence of PF varies significantly in different parts of Iran. Western province of Kermanshah has a significantly higher rate of PF. Adding data from different regions of Iran, we calculated that incidence of PF in Iran can be estimated between 1.14 to 10.48 per 100,000 of male populations, most probably closer to lower end. Although the incidence of PF varies significantly in different geographical areas, urologists practicing in Iran on average may encounter a PF patient every 3.5 months. To diagnose PF, majority of reviewed studies relied on history and clinical examination and did not recommend imaging except in patients with possible urethral injuries. Immediate surgical intervention can make good functional results with low morbidity and short hospital stay. Delayed surgical intervention and observational management approaches need large population studies with long term follow up.

A molecular mechanism of artemisinin resistance in Plasmodium falciparum malaria

PubMed Central

Mbengue, Alassane; Bhattacharjee, Souvik; Pandharkar, Trupti; Liu, Haining; Estiu, Guillermina; Stahelin, Robert V.; Rizk, Shahir; Njimoh, Dieudonne L.; Ryan, Yana; Chotivanich, Kesinee; Nguon, Chea; Ghorbal, Mehdi; Lopez-Rubio, Jose-Juan; Pfrender, Michael; Emrich, Scott; Mohandas, Narla; Dondorp, Arjen M.; Wiest, Olaf; Haldar, Kasturi

2015-01-01

Artemisinins are the corner stone of anti-malarial drugs1. Emergence and spread of resistance to them2–4 raises risk of wiping out recent gains achieved in reducing world-wide malaria burden and threatens future malaria control and elimination on a global level. Genome wide association studies (GWAS) have revealed parasite genetic loci associated with artemisinin resistance5–10. However, there is no consensus on biochemical targets of artemisinin. Whether and how these targets interact with genes identified by GWAS, remains unknown. Here we provide biochemical and cellular evidence that artemisinins are potent inhibitors of Plasmodium falciparum phosphatidylinositol-3-kinase (PfPI3K), revealing an unexpected mechanism of action. In resistant clinical strains, increased PfPI3K was associated with the C580Y mutation in P. falciparum Kelch13 (PfKelch13), a primary marker of artemisinin resistance. Polyubiquitination of PfPI3K and its binding to PfKelch13 were reduced by PfKelch13 mutation, which limited proteolysis of PfPI3K and thus increased levels of the kinase as well as its lipid product phosphatidylinositol 3-phosphate (PI3P). We find PI3P levels to be predictive of artemisinin resistance in both clinical and engineered laboratory parasites as well as across non-isogenic strains. Elevated PI3P induced artemisinin resistance in absence of PfKelch13 mutations, but remained responsive to regulation by PfKelch13. Evidence is presented for PI3P-dependent signaling, where transgenic expression of an additional kinase confers resistance. Together these data present PI3P as the key mediator of artemisinin resistance and the sole PfPI3K as an important target for malaria elimination. PMID:25874676

A molecular mechanism of artemisinin resistance in Plasmodium falciparum malaria.

PubMed

Mbengue, Alassane; Bhattacharjee, Souvik; Pandharkar, Trupti; Liu, Haining; Estiu, Guillermina; Stahelin, Robert V; Rizk, Shahir S; Njimoh, Dieudonne L; Ryan, Yana; Chotivanich, Kesinee; Nguon, Chea; Ghorbal, Mehdi; Lopez-Rubio, Jose-Juan; Pfrender, Michael; Emrich, Scott; Mohandas, Narla; Dondorp, Arjen M; Wiest, Olaf; Haldar, Kasturi

2015-04-30

Artemisinins are the cornerstone of anti-malarial drugs. Emergence and spread of resistance to them raises risk of wiping out recent gains achieved in reducing worldwide malaria burden and threatens future malaria control and elimination on a global level. Genome-wide association studies (GWAS) have revealed parasite genetic loci associated with artemisinin resistance. However, there is no consensus on biochemical targets of artemisinin. Whether and how these targets interact with genes identified by GWAS, remains unknown. Here we provide biochemical and cellular evidence that artemisinins are potent inhibitors of Plasmodium falciparum phosphatidylinositol-3-kinase (PfPI3K), revealing an unexpected mechanism of action. In resistant clinical strains, increased PfPI3K was associated with the C580Y mutation in P. falciparum Kelch13 (PfKelch13), a primary marker of artemisinin resistance. Polyubiquitination of PfPI3K and its binding to PfKelch13 were reduced by the PfKelch13 mutation, which limited proteolysis of PfPI3K and thus increased levels of the kinase, as well as its lipid product phosphatidylinositol-3-phosphate (PI3P). We find PI3P levels to be predictive of artemisinin resistance in both clinical and engineered laboratory parasites as well as across non-isogenic strains. Elevated PI3P induced artemisinin resistance in absence of PfKelch13 mutations, but remained responsive to regulation by PfKelch13. Evidence is presented for PI3P-dependent signalling in which transgenic expression of an additional kinase confers resistance. Together these data present PI3P as the key mediator of artemisinin resistance and the sole PfPI3K as an important target for malaria elimination.

Malaria Parasite-Infected Erythrocytes Secrete PfCK1, the Plasmodium Homologue of the Pleiotropic Protein Kinase Casein Kinase 1

PubMed Central

Dorin-Semblat, Dominique; Demarta-Gatsi, Claudia; Hamelin, Romain; Armand, Florence; Carvalho, Teresa Gil; Moniatte, Marc; Doerig, Christian

2015-01-01

Casein kinase 1 (CK1) is a pleiotropic protein kinase implicated in several fundamental processes of eukaryotic cell biology. Plasmodium falciparum encodes a single CK1 isoform, PfCK1, that is expressed at all stages of the parasite’s life cycle. We have previously shown that the pfck1 gene cannot be disrupted, but that the locus can be modified if no loss-of-function is incurred, suggesting an important role for this kinase in intra-erythrocytic asexual proliferation. Here, we report on the use of parasite lines expressing GFP- or His-tagged PfCK1 from the endogenous locus to investigate (i) the dynamics of PfCK1 localisation during the asexual cycle in red blood cells, and (ii) potential interactors of PfCK1, so as to gain insight into the involvement of the enzyme in specific cellular processes. Immunofluorescence analysis reveals a dynamic localisation of PfCK1, with evidence for a pool of the enzyme being directed to the membrane of the host erythrocyte in the early stages of infection, followed by a predominantly intra-parasite localisation in trophozoites and schizonts and association with micronemes in merozoites. Furthermore, we present strong evidence that a pool of enzymatically active PfCK1 is secreted into the culture supernatant, demonstrating that PfCK1 is an ectokinase. Our interactome experiments and ensuing kinase assays using recombinant PfCK1 to phosphorylate putative interactors in vitro suggest an involvement of PfCK1 in many cellular processes such as mRNA splicing, protein trafficking, ribosomal, and host cell invasion. PMID:26629826

Plantarflexor weakness negatively impacts walking in persons with multiple sclerosis more than plantarflexor spasticity

PubMed Central

Wagner, Joanne M.; Kremer, Theodore R.; Van Dillen, Linda R.; Naismith, Robert T.

2014-01-01

Objective To determine if plantarflexor (PF) spasticity or ankle strength best predicts variance in walking capacity or self-perceived limitations in walking in persons with multiple sclerosis (pwMS), and if pwMS with PF spasticity are weaker and have greater walking dysfunction than pwMS without PF spasticity. Design Cross-sectional study. Setting University research laboratory. Participants Forty-two pwMS (age: 42.9 ± 10.1 years; Expanded Disability Status Scale (EDSS): median = 3.0, range = 0–6) and 14 adults without disability (WD) (age: 41.9 ± 10.1 years). Intervention Not applicable. Main Outcome Measures PF spasticity and dorsiflexion (DF) and PF maximum voluntary isometric torque (MVIT) were assessed using the Modified Ashworth Scale (MAS) and a computerized dynamometer, respectively. The Timed 25-Foot Walk Test (T25FWT) was the primary outcome measure of walking capacity. Secondary measures included the Six Minute Walk Test (6MWT) and 12-item Multiple Sclerosis Walking Scale (MSWS-12). Results PF strength was the most consistent predictor of the variance in walking capacity (T25FWT: R2 change = 0.23 to 0.29, p ≤ 0.001; 6MWT: R2 change = 0.12 to 0.29, p ≤ 0.012), and self-perceived limitations of walking (MSWS-12: R2 change = 0.04 to 0.14, p < 0.18). There were no significant differences (p > 0.05) between the pwMS with PF spasticity and pwMS without PF spasticity for any of the outcome measures. Conclusions Our study suggests a unique contribution of PF weakness to walking dysfunction in pwMS, and highlights the importance of evaluating PF strength in this clinical population. PMID:24582617

PHISTc protein family members localize to different subcellular organelles and bind Plasmodium falciparum major virulence factor PfEMP-1.

PubMed

Kumar, Vikash; Kaur, Jasweer; Singh, Amrit P; Singh, Vineeta; Bisht, Anjali; Panda, Jiban J; Mishra, Prakash C; Hora, Rachna

2018-01-01

Plasmodium falciparum encodes a novel repertoire of the Plasmodium helical interspersed subtelomeric (PHIST) family of exported proteins, which play diverse roles in infected red blood cells, contributing to malaria pathogenesis. PHIST proteins are central to parasite biology and modify human erythrocytes by interacting with parasite and host proteins. Here, we have attempted to understand the localization and function of two unexplored proteins of the PHISTc subfamily, PFD1140w and PF11_0503, and compared these with a well-characterized member, PFI1780w. We demonstrate that Phist domains assume different oligomeric states owing to a distinct array of subunit interface residues. Colocalization of a Maurer's cleft signature protein, P. falciparum skeleton-binding protein-1 (PfSBP-1), and P. falciparum erythrocyte membrane protein-1 (PfEMP-1) revealed different subcellular destinations for these PHIST members. We further show the binding of recombinant PHIST proteins to the cytoplasmic tail of PfEMP-1 and a novel interaction with PfSBP-1. Interestingly, PFD1140w interacts with PfEMP-1 and PfSBP-1 simultaneously in vitro leading to formation of a complex. These two distant PHISTc members also bind PfEMP-1 on distinct sites, despite sharing the Phist domain. Our data re-emphasize a supportive role for PHIST proteins in cytoadhesion, and identify a new binding partner, PfSBP-1, for members of this family. This information therefore adds another chapter to the understanding of P. falciparum biology and highlights the significance of the unexplored PHIST family. © 2017 Federation of European Biochemical Societies.

Plantar fascia segmentation and thickness estimation in ultrasound images.

PubMed

Boussouar, Abdelhafid; Meziane, Farid; Crofts, Gillian

2017-03-01

Ultrasound (US) imaging offers significant potential in diagnosis of plantar fascia (PF) injury and monitoring treatment. In particular US imaging has been shown to be reliable in foot and ankle assessment and offers a real-time effective imaging technique that is able to reliably confirm structural changes, such as thickening, and identify changes in the internal echo structure associated with diseased or damaged tissue. Despite the advantages of US imaging, images are difficult to interpret during medical assessment. This is partly due to the size and position of the PF in relation to the adjacent tissues. It is therefore a requirement to devise a system that allows better and easier interpretation of PF ultrasound images during diagnosis. This study proposes an automatic segmentation approach which for the first time extracts ultrasound data to estimate size across three sections of the PF (rearfoot, midfoot and forefoot). This segmentation method uses artificial neural network module (ANN) in order to classify small overlapping patches as belonging or not-belonging to the region of interest (ROI) of the PF tissue. Features ranking and selection techniques were performed as a post-processing step for features extraction to reduce the dimension and number of the extracted features. The trained ANN classifies the image overlapping patches into PF and non-PF tissue, and then it is used to segment the desired PF region. The PF thickness was calculated using two different methods: distance transformation and area-length calculation algorithms. This new approach is capable of accurately segmenting the PF region, differentiating it from surrounding tissues and estimating its thickness. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.