Unilateral Congenital Cataract: Clinical Profile and Presentation.

PubMed

Khokhar, Sudarshan; Jose, Cijin P; Sihota, Ramanjit; Midha, Neha

2018-03-01

To study the clinical profile and presentation of children with unilateral cataract. In this hospital-based, observational, cross-sectional study, patients 15 years of age or younger who presented with unilateral cataract were recruited. Cases of cataract secondary to causes such as trauma or uveitis were excluded. Age at detection and presentation, distance from the treatment center, presenting complaints, cataract morphology, and biometry were noted for each case. A total of 76 patients were recruited. Most patients presented with complaints of leukocoria. Persistent fetal vasculature accounted for 27.6% of cases and was the most common identifiable cause of cataract in this study. Subsequently, patients were divided into two groups: no persistent fetal vasculature (control) and persistent fetal vasculature. A male predominance was noted in both groups. The mean age at detection was 27.58 ± 37.02 and 6.17 ± 8.42 months and the mean age at presentation was 55.613 ± 45.21 and 14.83 ± 17.75 months in the control and persistent fetal vasculature groups, respectively. In the persistent fetal vasculature group, a significant difference was noted in the axial length, keratometry, and corneal diameter between the affected and normal eyes (P = .027, .00176, and .0114, respectively). In the control group, this difference was observed only in keratometry readings (P = .0464). The mean distance traveled by patients to reach the treatment center was 211 km. Persistent fetal vasculature is an important and less identified cause of unilateral cataract. A significant delay is noted in the detection and presentation of unilateral cataract. [J Pediatr Ophthalmol Strabismus. 2018;55(2):107-112.]. Copyright 2017, SLACK Incorporated.

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein.

PubMed

Makky, Ali; Bousset, Luc; Polesel-Maris, Jérôme; Melki, Ronald

2016-11-30

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson's disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions. We recently established tightly controlled experimental conditions allowing the assembly of α-Syn into highly homogeneous and pure polymorphs. The latter exhibited differences in their shape, their structure but also in their functional properties. We have conducted an AFM study at high resolution and performed a statistical analysis of fibrillar α-Syn shape and thermal fluctuations to calculate the persistence length to further assess the nanomechanical properties of α-Syn polymorphs. Herein, we demonstrated quantitatively that distinct polymorphs made of the same protein (wild-type α-Syn) show significant differences in their morphology (height, width and periodicity) and physical properties (persistence length, bending rigidity and axial Young's modulus).

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein

NASA Astrophysics Data System (ADS)

Makky, Ali; Bousset, Luc; Polesel-Maris, Jérôme; Melki, Ronald

2016-11-01

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson’s disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions. We recently established tightly controlled experimental conditions allowing the assembly of α-Syn into highly homogeneous and pure polymorphs. The latter exhibited differences in their shape, their structure but also in their functional properties. We have conducted an AFM study at high resolution and performed a statistical analysis of fibrillar α-Syn shape and thermal fluctuations to calculate the persistence length to further assess the nanomechanical properties of α-Syn polymorphs. Herein, we demonstrated quantitatively that distinct polymorphs made of the same protein (wild-type α-Syn) show significant differences in their morphology (height, width and periodicity) and physical properties (persistence length, bending rigidity and axial Young’s modulus).

DNA compaction by poly (amido amine) dendrimers of ammonia cored and ethylene diamine cored

NASA Astrophysics Data System (ADS)

Qamhieh, K.; Al-Shawwa, J.

2017-06-01

The complexes build-up of DNA and soft particles poly amidoamine (PAMAM) dendrimers of ammonia cored of generations (G1-G6) and ethylenediamine cored of generations (G1-G10) have been studied, using a new theoretical model developed by Qamhieh and coworkers. The model describes the interaction between linear polyelectrolyte (LPE) chain and ion-penetrable spheres. Many factors affecting LPE/dendrimer complex have been investigated such as dendrimer generation, the Bjerrum length, salt concentration, and rigidity of the LPE chain represented by the persistence length. It is found that the wrapping chain length around dendrimer increases by increasing dendrimer`s generation, Bjerrum length, and salt concentration, while decreases by increasing the persistence length of the LPE chain. Also we can conclude that the wrapping length of LPE chain around ethylenediamine cored dendrimers is larger than its length around ammonia cored dendrimers.

Primary care visit length, quality, and satisfaction for standardized patients with depression.

PubMed

Geraghty, Estella M; Franks, Peter; Kravitz, Richard L

2007-12-01

The contribution of physician and organizational factors to visit length, quality, and satisfaction remains uncertain, in part, because of confounding by patient presentation. To determine associations among visit length, quality, and satisfaction when patient presentation is controlled. A factorial experiment using standardized patients to make primary care visits presenting with either major depression or adjustment disorder, and a musculoskeletal complaint. One hundred fifty-two primary care physicians, each seeing 2 standardized patients. Visit length was determined from surreptitiously obtained audiorecordings. Other key measures were derived from physician and standardized patient report. Mean visit length for 294 completed encounters was 22.3 minutes (range = 5.8-72.2, SD = 9.4). Key factors associated with visit length were: physician style (rho = 0.68 and 0.54 after multivariate adjustment), nonprofessional experience with depression (11% longer, 95% CI = 0-23%), practicing within an HMO (26% shorter, 95% CI = 61-90%), and greater practice volume (those working >9 half-day clinic sessions/week had 15% shorter visits than those working fewer than 6, 95% CI = 0-27%, and those seeing >12 patients/half-day had 27% shorter visits than those seeing <10 patients/half-day, 95% CI = 13-39%). Suicidal inquiry (a process-based quality-of-care measure for depression) was not associated with adjusted visit length. Satisfaction was linearly associated with visit length but not with suicide inquiry or follow-up interval. Despite experimental control for clinical presentation, wide variation in visit length persists, largely reflecting individual physician styles. Visit length is a significant determinant of standardized patient satisfaction.

Double-exponential decay of orientational correlations in semiflexible polyelectrolytes.

PubMed

Bačová, P; Košovan, P; Uhlík, F; Kuldová, J; Limpouchová, Z; Procházka, K

2012-06-01

In this paper we revisited the problem of persistence length of polyelectrolytes. We performed a series of Molecular Dynamics simulations using the Debye-Hückel approximation for electrostatics to test several equations which go beyond the classical description of Odijk, Skolnick and Fixman (OSF). The data confirm earlier observations that in the limit of large contour separations the decay of orientational correlations can be described by a single-exponential function and the decay length can be described by the OSF relation. However, at short countour separations the behaviour is more complex. Recent equations which introduce more complicated expressions and an additional length scale could describe the results very well on both the short and the long length scale. The equation of Manghi and Netz when used without adjustable parameters could capture the qualitative trend but deviated in a quantitative comparison. Better quantitative agreement within the estimated error could be obtained using three equations with one adjustable parameter: 1) the equation of Manghi and Netz; 2) the equation proposed by us in this paper; 3) the equation proposed by Cannavacciuolo and Pedersen. Two characteristic length scales can be identified in the data: the intrinsic or bare persistence length and the electrostatic persistence length. All three equations use a single parameter to describe a smooth crossover from the short-range behaviour dominated by the intrinsic stiffness of the chain to the long-range OSF-like behaviour.

Effects of sensory augmentation on postural control and gait symmetry of transfemoral amputees: a case description.

PubMed

Pagel, Anna; Arieta, Alejandro Hernandez; Riener, Robert; Vallery, Heike

2016-10-01

Despite recent advances in leg prosthetics, transfemoral amputees still experience limitations in postural control and gait symmetry. It has been hypothesized that artificial sensory information might improve the integration of the prosthesis into the human sensory-motor control loops and, thus, reduce these limitations. In three transfemoral amputees, we investigated the effect of Electrotactile Moving Sensation for Sensory Augmentation (EMSSA) without training and present preliminary findings. Experimental conditions included standing with open/closed eyes on stable/unstable ground as well as treadmill walking. For standing conditions, spatiotemporal posturographic measures and sample entropy were derived from the center of pressure. For walking conditions, step length and stance duration were calculated. Conditions without feedback showed effects congruent with findings in the literature, e.g., asymmetric weight bearing and step length, and validated the collected data. During standing, with EMSSA a tendency to influence postural control in a negative way was found: Postural control was less effective and less efficient and the prosthetic leg was less involved. Sample entropy tended to decrease, suggesting that EMSSA demanded increased attention. During walking, with EMSSA no persistent positive effect was found. This contrasts the positive subjective assessment and the positive effect on one subject's step length.

A PERSISTENT BONE GROWTH DEFICIT IN THE X-IRRADIATED RAT

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

Phillips, R.D.; Kimeldorf, D.J.

1964-02-10

ABS>A critical assessment of the roentgenographic technique was made for a quantitative determination of bone and tail length in the rat. The method was found to be very reliable if error sources were controlled and minimized. The early and long term effects of x irradiation on skeletal growth were investigated with respect to the age at exposure. Rats exposed at a juvenile age (37 days) to a sublethal dose (430 rad) exhibited a retardation in femur, tibia, and tail growth within 14 days after exposure. The maximum deficit was attained within 30 days after exposure and remained approximately constant formore » the next 300 days. Femur and tibia length of animals which were exposed to x rays as young adults (101 days of age) did not differ from those of controls for the first two months after exposure. However, there was a deficit in femur and tibia length in these animals at the end of life span. The magnitude of the bone length reduction at the end of life span was dose dependent. The two major differences in response between the two age groups were the time course of the radiation effect on growth and the magnitude of the deficit. The reduction in bone length occurred faster and was greater in the younger irradiated group. (auth)« less

FLP-18 Functions through the G-Protein-Coupled Receptors NPR-1 and NPR-4 to Modulate Reversal Length in Caenorhabditis elegans

PubMed Central

Dahiya, Yogesh; Babu, Kavita

2018-01-01

Animal behavior is critically dependent on the activity of neuropeptides. Reversals, one of the most conspicuous behaviors in Caenorhabditis elegans, plays an important role in determining the navigation strategy of the animal. Our experiments on hermaphrodite C. elegans show the involvement of a neuropeptide FLP-18 in modulating reversal length in these hermaphrodites. We show that FLP-18 controls the reversal length by regulating the activity of AVA interneurons through the G-protein-coupled neuropeptide receptors, NPR-4 and NPR-1. We go on to show that the site of action of these receptors is the AVA interneuron for NPR-4 and the ASE sensory neurons for NPR-1. We further show that mutants in the neuropeptide, flp-18, and its receptors show increased reversal lengths. Consistent with the behavioral data, calcium levels in the AVA neuron of freely reversing C. elegans were significantly higher and persisted for longer durations in flp-18, npr-1, npr-4, and npr-1 npr-4 genetic backgrounds compared with wild-type control animals. Finally, we show that increasing FLP-18 levels through genetic and physiological manipulations causes shorter reversal lengths. Together, our analysis suggests that the FLP-18/NPR-1/NPR-4 signaling is a pivotal point in the regulation of reversal length under varied genetic and environmental conditions. PMID:29712787

Preferential selection based on strategy persistence and memory promotes cooperation in evolutionary prisoner's dilemma games

NASA Astrophysics Data System (ADS)

Liu, Yuanming; Huang, Changwei; Dai, Qionglin

2018-06-01

Strategy imitation plays a crucial role in evolutionary dynamics when we investigate the spontaneous emergence of cooperation under the framework of evolutionary game theory. Generally, when an individual updates his strategy, he needs to choose a role model whom he will learn from. In previous studies, individuals choose role models randomly from their neighbors. In recent works, researchers have considered that individuals choose role models according to neighbors' attractiveness characterized by the present network topology or historical payoffs. Here, we associate an individual's attractiveness with the strategy persistence, which characterizes how frequently he changes his strategy. We introduce a preferential parameter α to describe the nonlinear correlation between the selection probability and the strategy persistence and the memory length of individuals M into the evolutionary games. We investigate the effects of α and M on cooperation. Our results show that cooperation could be promoted when α > 0 and at the same time M > 1, which corresponds to the situation that individuals are inclined to select their neighbors with relatively higher persistence levels during the evolution. Moreover, we find that the cooperation level could reach the maximum at an optimal memory length when α > 0. Our work sheds light on how to promote cooperation through preferential selection based on strategy persistence and a limited memory length.

Nanomechanical properties of distinct fibrillar polymorphs of the protein α-synuclein

PubMed Central

Makky, Ali; Bousset, Luc; Polesel-Maris, Jérôme; Melki, Ronald

2016-01-01

Alpha-synuclein (α-Syn) is a small presynaptic protein of 140 amino acids. Its pathologic intracellular aggregation within the central nervous system yields protein fibrillar inclusions named Lewy bodies that are the hallmarks of Parkinson’s disease (PD). In solution, pure α-Syn adopts an intrinsically disordered structure and assembles into fibrils that exhibit considerable morphological heterogeneity depending on their assembly conditions. We recently established tightly controlled experimental conditions allowing the assembly of α-Syn into highly homogeneous and pure polymorphs. The latter exhibited differences in their shape, their structure but also in their functional properties. We have conducted an AFM study at high resolution and performed a statistical analysis of fibrillar α-Syn shape and thermal fluctuations to calculate the persistence length to further assess the nanomechanical properties of α-Syn polymorphs. Herein, we demonstrated quantitatively that distinct polymorphs made of the same protein (wild-type α-Syn) show significant differences in their morphology (height, width and periodicity) and physical properties (persistence length, bending rigidity and axial Young’s modulus). PMID:27901068

Salivary Telomere Length and Lung Function in Adolescents Born Very Preterm: A Prospective Multicenter Study.

PubMed

Hadchouel, Alice; Marchand-Martin, Laetitia; Franco-Montoya, Marie-Laure; Peaudecerf, Laetitia; Ancel, Pierre-Yves; Delacourt, Christophe

2015-01-01

Preterm birth is associated with abnormal respiratory functions throughout life. The mechanisms underlying these long-term consequences are still unclear. Shortening of telomeres was associated with many conditions, such as chronic obstructive pulmonary disease. We aimed to search for an association between telomere length and lung function in adolescents born preterm. Lung function and telomere length were measured in 236 adolescents born preterm and 38 born full-term from the longitudinal EPIPAGE cohort. Associations between telomere length and spirometric indices were tested in univariate and multivariate models accounting for confounding factors in the study population. Airflows were significantly lower in adolescents born preterm than controls; forced expiratory volume in one second was 12% lower in the extremely preterm born group than controls (p<0.001). Lower birth weight, bronchopulmonary dysplasia and postnatal sepsis were significantly associated with lower airflow values. Gender was the only factor that was significantly associated with telomere length. Telomere length correlated with forced expiratory flow 25-75 in the extremely preterm adolescent group in univariate and multivariate analyses (p = 0.01 and p = 0.02, respectively). We evidenced an association between telomere length and abnormal airflow in a population of adolescents born extremely preterm. There was no evident association with perinatal events. This suggests other involved factors, such as a continuing airway oxidative stress leading to persistent inflammation and altered lung function, ultimately increasing susceptibility to chronic obstructive pulmonary disease.

Semiflexible macromolecules in quasi-one-dimensional confinement: Discrete versus continuous bond angles.

PubMed

Huang, Aiqun; Hsu, Hsiao-Ping; Bhattacharya, Aniket; Binder, Kurt

2015-12-28

The conformations of semiflexible polymers in two dimensions confined in a strip of width D are studied by computer simulations, investigating two different models for the mechanism by which chain stiffness is realized. One model (studied by molecular dynamics) is a bead-spring model in the continuum, where stiffness is controlled by a bond angle potential allowing for arbitrary bond angles. The other model (studied by Monte Carlo) is a self-avoiding walk chain on the square lattice, where only discrete bond angles (0° and ±90°) are possible, and the bond angle potential then controls the density of kinks along the chain contour. The first model is a crude description of DNA-like biopolymers, while the second model (roughly) describes synthetic polymers like alkane chains. It is first demonstrated that in the bulk the crossover from rods to self-avoiding walks for both models is very similar, when one studies average chain linear dimensions, transverse fluctuations, etc., despite their differences in local conformations. However, in quasi-one-dimensional confinement two significant differences between both models occur: (i) The persistence length (extracted from the average cosine of the bond angle) gets renormalized for the lattice model when D gets less than the bulk persistence length, while in the continuum model it stays unchanged. (ii) The monomer density near the repulsive walls for semiflexible polymers is compatible with a power law predicted for the Kratky-Porod model in the case of the bead-spring model, while for the lattice case it tends to a nonzero constant across the strip. However, for the density of chain ends, such a constant behavior seems to occur for both models, unlike the power law observed for flexible polymers. In the regime where the bulk persistence length ℓp is comparable to D, hairpin conformations are detected, and the chain linear dimensions are discussed in terms of a crossover from the Daoud/De Gennes "string of blobs"-picture to the flexible rod picture when D decreases and/or the chain stiffness increases. Introducing a suitable further coarse-graining of the chain contours of the continuum model, direct estimates for the deflection length and its distribution could be obtained.

From strings to coils: Rotational dynamics of DNA-linked colloidal chains

NASA Astrophysics Data System (ADS)

Kuei, Steve; Garza, Burke; Biswal, Sibani Lisa

2017-10-01

We investigate the dynamical behavior of deformable filaments experimentally using a tunable model system consisting of linked paramagnetic colloidal particles, where the persistence length lp, the contour length lc, and the strength and frequency of the external driving force are controlled. We find that upon forcing by an external magnetic field, a variety of structural and conformational regimes exist. Depending on the competition of forces and torques on the chain, we see classic rigid rotator behavior, as well as dynamically rich wagging, coiling, and folding behavior. Through a combination of experiments, computational models, and theoretical calculations, we are able to observe, classify, and predict these dynamics as a function of the dimensionless Mason and magnetoelastic numbers.

Rational temporal predictions can underlie apparent failures to delay gratification.

PubMed

McGuire, Joseph T; Kable, Joseph W

2013-04-01

An important category of seemingly maladaptive decisions involves failure to postpone gratification. A person pursuing a desirable long-run outcome may abandon it in favor of a short-run alternative that has been available all along. Here we present a theoretical framework in which this seemingly irrational behavior emerges from stable preferences and veridical judgments. Our account recognizes that decision makers generally face uncertainty regarding the time at which future outcomes will materialize. When timing is uncertain, the value of persistence depends crucially on the nature of a decision maker's prior temporal beliefs. Certain forms of temporal beliefs imply that a delay's predicted remaining length increases as a function of time already waited. In this type of situation, the rational, utility-maximizing strategy is to persist for a limited amount of time and then give up. We show empirically that people's explicit predictions of remaining delay lengths indeed increase as a function of elapsed time in several relevant domains, implying that temporal judgments offer a rational basis for limiting persistence. We then develop our framework into a simple working model and show how it accounts for individual differences in a laboratory task (the well-known "marshmallow test"). We conclude that delay-of-gratification failure, generally viewed as a manifestation of limited self-control capacity, can instead arise as an adaptive response to the perceived statistics of one's environment.

Rational temporal predictions can underlie apparent failures to delay gratification

PubMed Central

McGuire, Joseph T.; Kable, Joseph W.

2013-01-01

An important category of seemingly maladaptive decisions involves failure to postpone gratification. A person pursuing a desirable long-run outcome may abandon it in favor of a short-run alternative that has been available all along. Here we present a theoretical framework in which this seemingly irrational behavior emerges from stable preferences and veridical judgments. Our account recognizes that decision makers generally face uncertainty regarding the time at which future outcomes will materialize. When timing is uncertain, the value of persistence depends crucially on the nature of a decision-maker’s prior temporal beliefs. Certain forms of temporal beliefs imply that a delay’s predicted remaining length increases as a function of time already waited. In this type of situation, the rational, utility-maximizing strategy is to persist for a limited amount of time and then give up. We show empirically that people’s explicit predictions of remaining delay lengths indeed increase as a function of elapsed time in several relevant domains, implying that temporal judgments offer a rational basis for limiting persistence. We then develop our framework into a simple working model and show how it accounts for individual differences in a laboratory task (the well-known “marshmallow test”). We conclude that delay-of-gratification failure, generally viewed as a manifestation of limited self-control capacity, can instead arise as an adaptive response to the perceived statistics of one’s environment. PMID:23458085

Definition of the persistence length in the coarse-grained models of DNA elasticity.

PubMed

Fathizadeh, A; Eslami-Mossallam, B; Ejtehadi, M R

2012-11-01

By considering the detailed structure of DNA in the base pair level, two possible definitions of the persistence length are compared. One definition is related to the orientation of the terminal base pairs, and the other is based on the vectors which connect two adjacent base pairs at each end of the molecule. It is shown that although these definitions approach each other for long DNA molecules, they are dramatically different on short length scales. We show analytically that the difference mostly comes from the shear flexibility of the molecule and can be used to measure the shear modulus of DNA.

Electrostatic stiffening and induced persistence length for coassembled molecular bottlebrushes

NASA Astrophysics Data System (ADS)

Storm, Ingeborg M.; Stuart, Martien A. Cohen; de Vries, Renko; Leermakers, Frans A. M.

2018-03-01

A self-consistent field analysis for tunable contributions to the persistence length of isolated semiflexible polymer chains including electrostatically driven coassembled deoxyribonucleic acid (DNA) bottlebrushes is presented. When a chain is charged, i.e., for polyelectrolytes, there is, in addition to an intrinsic rigidity, an electrostatic stiffening effect, because the electric double layer resists bending. For molecular bottlebrushes, there is an induced contribution due to the grafts. We explore cases beyond the classical phantom main-chain approximation and elaborate molecularly more realistic models where the backbone has a finite volume, which is necessary for treating coassembled bottlebrushes. We find that the way in which the linear charge density or the grafting density is regulated is important. Typically, the stiffening effect is reduced when there is freedom for these quantities to adapt to the curvature stresses. Electrostatically driven coassembled bottlebrushes, however, are relatively stiff because the chains have a low tendency to escape from the compressed regions and the electrostatic binding force is largest in the convex part. For coassembled bottlebrushes, the induced persistence length is a nonmonotonic function of the polymer concentration: For low polymer concentrations, the stiffening grows quadratically with coverage; for semidilute polymer concentrations, the brush chains retract and regain their Gaussian size. When doing so, they lose their induced persistence length contribution. Our results correlate well with observed physical characteristics of electrostatically driven coassembled DNA-bioengineered protein-polymer bottlebrushes.

End-monomer Dynamics in Semiflexible Polymers

PubMed Central

Hinczewski, Michael; Schlagberger, Xaver; Rubinstein, Michael; Krichevsky, Oleg; Netz, Roland R.

2009-01-01

Spurred by an experimental controversy in the literature, we investigate the end-monomer dynamics of semiflexible polymers through Brownian hydrodynamic simulations and dynamic mean-field theory. Precise experimental observations over the last few years of end-monomer dynamics in the diffusion of double-stranded DNA have given conflicting results: one study indicated an unexpected Rouse-like scaling of the mean squared displacement (MSD) 〈r2(t)〉 ~ t1/2 at intermediate times, corresponding to fluctuations at length scales larger than the persistence length but smaller than the coil size; another study claimed the more conventional Zimm scaling 〈r2(t)〉 ~ t2/3 in the same time range. Using hydrodynamic simulations, analytical and scaling theories, we find a novel intermediate dynamical regime where the effective local exponent of the end-monomer MSD, α(t) = d log〈r2(t)〉/d log t, drops below the Zimm value of 2/3 for sufficiently long chains. The deviation from the Zimm prediction increases with chain length, though it does not reach the Rouse limit of 1/2. The qualitative features of this intermediate regime, found in simulations and in an improved mean-field theory for semiflexible polymers, in particular the variation of α(t) with chain and persistence lengths, can be reproduced through a heuristic scaling argument. Anomalously low values of the effective exponent α are explained by hydrodynamic effects related to the slow crossover from dynamics on length scales smaller than the persistence length to dynamics on larger length scales. PMID:21359118

The assessment of postural control and the influence of a secondary task in people with anterior cruciate ligament reconstructed knees using a Nintendo Wii Balance Board.

PubMed

Howells, Brooke E; Clark, Ross A; Ardern, Clare L; Bryant, Adam L; Feller, Julian A; Whitehead, Timothy S; Webster, Kate E

2013-09-01

Postural control impairments may persist following anterior cruciate ligament (ACL) reconstruction. The effect of a secondary task on postural control has, however, not been determined. The purpose of this case-control study was to compare postural control in patients following ACL reconstruction with healthy individuals with and without a secondary task. 45 patients (30 men and 15 women) participated at least 6 months following primary ACL reconstruction surgery. Participants were individually matched by age, gender and sports activity to healthy controls. Postural control was measured using a Nintendo Wii Balance Board and customised software during static single-leg stance and with the addition of a secondary task. The secondary task required participants to match the movement of an oscillating marker by adducting and abducting their arm. Centre of pressure (CoP) path length in both medial-lateral and anterior-posterior directions, and CoP total path length. When compared with the control group, the anterior-posterior path length significantly increased in the ACL reconstruction patients' operated (12.3%, p=0.02) and non-operated limbs (12.8%, p=0.02) for the single-task condition, and the non-operated limb (11.5%, p=0.006) for the secondary task condition. The addition of a secondary task significantly increased CoP path lengths in all measures (p<0.001), although the magnitude of the increase was similar in both the ACL reconstruction and control groups. ACL reconstruction patients showed a reduced ability in both limbs to control the movement of the body in the anterior-posterior direction. The secondary task affected postural control by comparable amounts in patients after ACL reconstruction and healthy controls. Devices for the objective measurement of postural control, such as the one used in this study, may help clinicians to more accurately identify patients with deficits who may benefit from targeted neuromuscular training programs.

Tying Knots in DNA with Holographic Optical Tweezers

NASA Astrophysics Data System (ADS)

Miles, Mervyn; Foster, David; Seddon, Annela; Phillips, David; Carberry, David; Padgett, Miles; Dennis, Mark

It has been demonstrated that holographic optical tweezers can be used to tie a trefoil knot in double-stranded DNA. We have developed an advanced holographic optical tweezers system with several types of intuitive control interfaces. It has been used in a range of research projects including the characterization and assembly of structures. Here the process of tying increasingly complex knots with holographic tweezers will be described. The DNA is of the order of 50 μ m in length and is fluorescently labeled, in order that it can be visualized in the optical microscope of the tweezers system. With a knot was tied, the effect of increasing the persistence length of the DNA by partial methylation of the DNA molecule was investigated. Leverhulme Trust.

Elasticity of short DNA molecules: theory and experiment for contour lengths of 0.6-7 microm.

PubMed

Seol, Yeonee; Li, Jinyu; Nelson, Philip C; Perkins, Thomas T; Betterton, M D

2007-12-15

The wormlike chain (WLC) model currently provides the best description of double-stranded DNA elasticity for micron-sized molecules. This theory requires two intrinsic material parameters-the contour length L and the persistence length p. We measured and then analyzed the elasticity of double-stranded DNA as a function of L (632 nm-7.03 microm) using the classic solution to the WLC model. When the elasticity data were analyzed using this solution, the resulting fitted value for the persistence length p(wlc) depended on L; even for moderately long DNA molecules (L = 1300 nm), this apparent persistence length was 10% smaller than its limiting value for long DNA. Because p is a material parameter, and cannot depend on length, we sought a new solution to the WLC model, which we call the "finite wormlike chain (FWLC)," to account for effects not considered in the classic solution. Specifically we accounted for the finite chain length, the chain-end boundary conditions, and the bead rotational fluctuations inherent in optical trapping assays where beads are used to apply the force. After incorporating these corrections, we used our FWLC solution to generate force-extension curves, and then fit those curves with the classic WLC solution, as done in the standard experimental analysis. These results qualitatively reproduced the apparent dependence of p(wlc) on L seen in experimental data when analyzed with the classic WLC solution. Directly fitting experimental data to the FWLC solution reduces the apparent dependence of p(fwlc) on L by a factor of 3. Thus, the FWLC solution provides a significantly improved theoretical framework in which to analyze single-molecule experiments over a broad range of experimentally accessible DNA lengths, including both short (a few hundred nanometers in contour length) and very long (microns in contour length) molecules.

A Lag in Speech Motor Coordination during Sentence Production Is Associated with Stuttering Persistence in Young Children

ERIC Educational Resources Information Center

Usler, Evan; Smith, Anne; Weber, Christine

2017-01-01

Purpose: The purpose of this study was to determine if indices of speech motor coordination during the production of sentences varying in sentence length and syntactic complexity were associated with stuttering persistence versus recovery in 5- to 7-year-old children. Methods: We compared children with persistent stuttering (CWS-Per) with children…

Structure and dynamics of hyaluronic acid semidilute solutions: a dielectric spectroscopy study.

PubMed

Vuletić, T; Dolanski Babić, S; Ivek, T; Grgicin, D; Tomić, S; Podgornik, R

2010-07-01

Dielectric spectroscopy is used to investigate fundamental length scales describing the structure of hyaluronic acid sodium salt (Na-HA) semidilute aqueous solutions. In salt-free regime, the length scale of the relaxation mode detected in MHz range scales with HA concentration as c(HA)(-0.5) and corresponds to the de Gennes-Pfeuty-Dobrynin correlation length of polyelectrolytes in semidilute solution. The same scaling was observed for the case of long, genomic DNA. Conversely, the length scale of the mode detected in kilohertz range also varies with HA concentration as c(HA)(-0.5) which differs from the case of DNA (c(DNA)(-0.25)). The observed behavior suggests that the relaxation in the kilohertz range reveals the de Gennes-Dobrynin renormalized Debye screening length, and not the average size of the chain, as the pertinent length scale. Similarly, with increasing added salt the electrostatic contribution to the HA persistence length is observed to scale as the Debye length, contrary to scaling pertinent to the Odijk-Skolnick-Fixman electrostatic persistence length observed in the case of DNA. We argue that the observed features of the kilohertz range relaxation are due to much weaker electrostatic interactions that lead to the absence of Manning condensation as well as a rather high flexibility of HA as compared to DNA.

Persistence length changes dramatically as RNA folds.

PubMed

Caliskan, G; Hyeon, C; Perez-Salas, U; Briber, R M; Woodson, S A; Thirumalai, D

2005-12-31

We determine the persistence length l(p) for a bacterial group I ribozyme as a function of concentration of monovalent and divalent cations by fitting the distance distribution functions P(r) obtained from small angle x-ray scattering intensity data to the asymptotic form of the calculated P(WLC)(r) for a wormlike chain. The l(p) values change dramatically over a narrow range of Mg(2+) concentration from approximately 21 Angstroms in the unfolded state (U) to approximately 10 Angstroms in the compact (I(C)) and native states. Variations in l(p) with increasing Na(+) concentration are more gradual. In accord with the predictions of polyelectrolyte theory we find l(p) alpha 1/kappa(2) where kappa is the inverse Debye-screening length.

FibrilJ: ImageJ plugin for fibrils' diameter and persistence length determination

NASA Astrophysics Data System (ADS)

Sokolov, P. A.; Belousov, M. V.; Bondarev, S. A.; Zhouravleva, G. A.; Kasyanenko, N. A.

2017-05-01

Application of microscopy to evaluate the morphology and size of filamentous proteins and amyloids requires new and creative approaches to simplify and automate the image processing. The estimation of mean values of fibrils diameter, length and bending stiffness on micrographs is a major challenge. For this purpose we developed an open-source FibrilJ plugin for the ImageJ/FiJi program. It automatically recognizes the fibrils on the surface of a mica, silicon, gold or formvar film and further analyzes them to calculate the distribution of fibrils by diameters, lengths and persistence lengths. The plugin has been validated by the processing of TEM images of fibrils formed by Sup35NM yeast protein and artificially created images of rod-shape objects with predefined parameters. Novel data obtained by SEM for Sup35NM protein fibrils immobilized on silicon and gold substrates are also presented and analyzed.

Non-linear dynamics of human locomotion: effects of rhythmic auditory cueing on local dynamic stability.

PubMed

Terrier, Philippe; Dériaz, Olivier

2013-01-01

It has been observed that times series of gait parameters [stride length (SL), stride time (ST), and stride speed (SS)], exhibit long-term persistence and fractal-like properties. Synchronizing steps with rhythmic auditory stimuli modifies the persistent fluctuation pattern to anti-persistence. Another non-linear method estimates the degree of resilience of gait control to small perturbations, i.e., the local dynamic stability (LDS). The method makes use of the maximal Lyapunov exponent, which estimates how fast a non-linear system embedded in a reconstructed state space (attractor) diverges after an infinitesimal perturbation. We propose to use an instrumented treadmill to simultaneously measure basic gait parameters (time series of SL, ST, and SS from which the statistical persistence among consecutive strides can be assessed), and the trajectory of the center of pressure (from which the LDS can be estimated). In 20 healthy participants, the response to rhythmic auditory cueing (RAC) of LDS and of statistical persistence [assessed with detrended fluctuation analysis (DFA)] was compared. By analyzing the divergence curves, we observed that long-term LDS (computed as the reverse of the average logarithmic rate of divergence between the 4th and the 10th strides downstream from nearest neighbors in the reconstructed attractor) was strongly enhanced (relative change +73%). That is likely the indication of a more dampened dynamics. The change in short-term LDS (divergence over one step) was smaller (+3%). DFA results (scaling exponents) confirmed an anti-persistent pattern in ST, SL, and SS. Long-term LDS (but not short-term LDS) and scaling exponents exhibited a significant correlation between them (r = 0.7). Both phenomena probably result from the more conscious/voluntary gait control that is required by RAC. We suggest that LDS and statistical persistence should be used to evaluate the efficiency of cueing therapy in patients with neurological gait disorders.

Active microrheology of entangled biopolymer composites link polymer flexibility and length to molecular force response

NASA Astrophysics Data System (ADS)

Fitzpatrick, Robert; Hauer, Cole; Kyrillos, Carl; McGorty, Ryan; Robertson-Anderson, Rae

Entangled polymers have complex viscoelastic properties that are tuned by polymer lengths and flexibilities. Entangled composites of distinct polymers offer added versatility and display nonlinear mechanics, serving as a platform for multifunctional materials. To determine the role of flexibility and length in polymer composites we use optical tweezers and confocal microscopy to measure mechanical and structural properties of co-entangled actin and DNA. Actin filaments have lengths of 5-20 μm, comparable to their persistence length, while DNA of similar lengths have hundreds of persistence lengths per chain. To characterize the nonlinear mechanics of actin-DNA composites, we optically drive a microsphere through the composite and measure the induced force during and following strain. We characterize viscoelasticity and relaxation timescales; and determine the dependence of these quantities on the actin:DNA ratio (0:1-1:0) and DNA length (4-100 μm). We use confocal microscopy to image distinctly labeled co-entangled actin and DNA and characterize network homogeneity and fluctuations. Initial results show actin and DNA are well-integrated and form structurally homogenous networks that exhibit stiffness and relaxation times that increase nonlinearly with increased actin. NSF Career Award (DMR-1254340), AFOSR Young Investigator Program Award (FA95550-12-1-0315), Scialog Collaborative Innovation Award funed by Research Corp. for Scientific Advancement (24192).

Current Perspectives of Telomerase Structure and Function in Eukaryotes with Emerging Views on Telomerase in Human Parasites.

PubMed

Dey, Abhishek; Chakrabarti, Kausik

2018-01-24

Replicative capacity of a cell is strongly correlated with telomere length regulation. Aberrant lengthening or reduction in the length of telomeres can lead to health anomalies, such as cancer or premature aging. Telomerase is a master regulator for maintaining replicative potential in most eukaryotic cells. It does so by controlling telomere length at chromosome ends. Akin to cancer cells, most single-cell eukaryotic pathogens are highly proliferative and require persistent telomerase activity to maintain constant length of telomere and propagation within their host. Although telomerase is key to unlimited cellular proliferation in both cases, not much was known about the role of telomerase in human parasites (malaria, Trypanosoma , etc.) until recently. Since telomerase regulation is mediated via its own structural components, interactions with catalytic reverse transcriptase and several factors that can recruit and assemble telomerase to telomeres in a cell cycle-dependent manner, we compare and discuss here recent findings in telomerase biology in cancer, aging and parasitic diseases to give a broader perspective of telomerase function in human diseases.

Kinetics of interior loop formation in semiflexible chains.

PubMed

Hyeon, Changbong; Thirumalai, D

2006-03-14

Loop formation between monomers in the interior of semiflexible chains describes elementary events in biomolecular folding and DNA bending. We calculate analytically the interior distance distribution function for semiflexible chains using a mean field approach. Using the potential of mean force derived from the distance distribution function we present a simple expression for the kinetics of interior looping by adopting Kramers theory. For the parameters, that are appropriate for DNA, the theoretical predictions in comparison with the case are in excellent agreement with explicit Brownian dynamics simulations of wormlike chain (WLC) model. The interior looping times (tauIC) can be greatly altered in the cases when the stiffness of the loop differs from that of the dangling ends. If the dangling end is stiffer than the loop then tauIC increases for the case of the WLC with uniform persistence length. In contrast, attachment of flexible dangling ends enhances rate of interior loop formation. The theory also shows that if the monomers are charged and interact via screened Coulomb potential then both the cyclization (tauc) and interior looping (tauIC) times greatly increase at low ionic concentration. Because both tauc and tauIC are determined essentially by the effective persistence length [lp(R)] we computed lp(R) by varying the range of the repulsive interaction between the monomers. For short range interactions lp(R) nearly coincides with the bare persistence length which is determined largely by the backbone chain connectivity. This finding rationalizes the efficacy of describing a number of experimental observations (response of biopolymers to force and cyclization kinetics) in biomolecules using WLC model with an effective persistence length.

Persistence Characteristics of Wind-Tunnel Pressure Signatures From Two Similar Models

NASA Technical Reports Server (NTRS)

Mack, Robert J.

2004-01-01

Pressure signatures generated by two sonic-boom wind-tunnel models and measured at Mach 2 are presented, analyzed, and discussed. The two wind-tunnel models differed in length and span by a factor of fourteen, but were similar in wing-body planform shape. The geometry of the larger model had been low-boom tailored to generate a flat top ground pressure signature, and the nacelles-off pressure signatures from this model became more flattop in shape as the model-probe separation distances increased from 0.94 to 4.4 span lengths. The geometry of the smaller model had not been low-boom tailored, yet its measured pressure signatures had non-N-wave shapes that persisted as model-probe separation distances increased from 26.0 to 104.2 span lengths. Since the overall planforms of the two wind-tunnel models were so similar, it was concluded that the shape-persistence trends in the pressure signatures of the smaller, non-low-boom tailored model would also be present at very large distances in the pressure signatures of the larger, low-boom-tailored model.

Effect of genomic long-range correlations on DNA persistence length: from theory to single molecule experiments.

PubMed

Moukhtar, Julien; Faivre-Moskalenko, Cendrine; Milani, Pascale; Audit, Benjamin; Vaillant, Cedric; Fontaine, Emeline; Mongelard, Fabien; Lavorel, Guillaume; St-Jean, Philippe; Bouvet, Philippe; Argoul, Françoise; Arneodo, Alain

2010-04-22

Sequence dependency of DNA intrinsic bending properties has been emphasized as a possible key ingredient to in vivo chromatin organization. We use atomic force microscopy (AFM) in air and liquid to image intrinsically straight (synthetic), uncorrelated (hepatitis C RNA virus) and persistent long-range correlated (human) DNA fragments in various ionic conditions such that the molecules freely equilibrate on the mica surface before being captured in a particular conformation. 2D thermodynamic equilibrium is experimentally verified by a detailed statistical analysis of the Gaussian nature of the DNA bend angle fluctuations. We show that the worm-like chain (WLC) model, commonly used to describe the average conformation of long semiflexible polymers, reproduces remarkably well the persistence length estimates for the first two molecules as consistently obtained from (i) mean square end-to-end distance measurement and (ii) mean projection of the end-to-end vector on the initial orientation. Whatever the operating conditions (air or liquid, concentration of metal cations Mg(2+) and/or Ni(2+)), the persistence length found for the uncorrelated viral DNA underestimates the value obtained for the straight DNA. We show that this systematic difference is the signature of the presence of an uncorrelated structural intrinsic disorder in the hepatitis C virus (HCV) DNA fragment that superimposes on local curvatures induced by thermal fluctuations and that only the entropic disorder depends upon experimental conditions. In contrast, the WLC model fails to describe the human DNA conformations. We use a mean-field extension of the WLC model to account for the presence of long-range correlations (LRC) in the intrinsic curvature disorder of human genomic DNA: the stronger the LRC, the smaller the persistence length. The comparison of AFM imaging of human DNA with LRC DNA simulations confirms that the rather small mean square end-to-end distance observed, particularly for G+C-rich human DNA molecules, more likely results from a large-scale intrinsic curvature due to a persistent distribution of DNA curvature sites than from some increased flexibility.

Universal aspects of conformations and transverse fluctuations of a two-dimensional semi-flexible chain

NASA Astrophysics Data System (ADS)

Hsu, Hsiao-Ping; Huang, Aiqun; Bhattacharya, Aniket; Binder, Kurt

2015-03-01

In this talk we compare the results obtained from Monte Carlo (MC) and Brownian dynamics (BD) simulation for the universal properties of a semi-flexible chain. Specifically we compare MC results obtained using pruned-enriched Rosenbluth method (PERM) with those obtained from BD simulation. We find that the scaled plot of root-mean-square (RMS) end-to-end distance / 2 Llp and RMS transverse transverse fluctuations √{ } /lp as a function of L /lp (where L and lp are the contour length, and the persistence length respectively) are universal and independent of the definition of the persistence length used in MC and BD schemes. We further investigate to what extent these results agree for a semi-flexible polymer confined in a quasi one dimensional channel.

The effect of lipid monolayer in-plane rigidity on in vivo microbubble circulation persistence

PubMed Central

Garg, Sumit; Thomas, Alex A.; Borden, Mark A.

2013-01-01

The goal of this study was to increase in vivo microbubble circulation persistence for applications in medical imaging and targeted drug delivery. Our approach was to investigate the effect of lipid monolayer in-plane rigidity to reduce the rate of microbubble dissolution, while holding constant the microbubble size, concentration and surface architecture. We first estimated the impact of acyl chain length of the main diacyl phosphatidyl-choline (PC) lipid and inter-lipid distance on the cohesive surface energy and, based on these results, we hypothesized that microbubble stability and in vivo ultrasound contrast persistence would increase monotonically with increasing acyl chain length. We therefore measured microbubble in vitro stability to dilution with and without ultrasound exposure, as well as in vivo ultrasound contrast persistence. All measurements showed a sharp rise in stability between DPPC (C16:0) and DSPC (C18:0), which correlates to the wrinkling transition, which signals the onset of significant surface shear and gas permeation resistance, observed in prior single-bubble dissolution studies. Further evidence for the effect of the wrinkling transition came from an in vitro and in vivo stability comparison of microbubbles coated with pure DPPC with those of lung surfactant extract. Microbubble stability against dilution without ultrasound and in vivo ultrasound contrast persistence showed a monotonic increase with acyl chain length from DSPC to DBPC (C22:0). However, we also observed that stability dropped precipitously for all measurements on further increasing lipid acyl chain length from DBPC to DLiPC (C24:0). This result suggests that hydrophobic mismatch between the main PC lipid and the lipopolymer emulsifier, DSPE-PEG5000, may drive a less stable surface microstructure. Overall, these results support our general hypothesis of the role of in-plane rigidity for increasing the lifetime of microbubble circulation. PMID:23787108

Persistence in a Two-Dimensional Moving-Habitat Model.

PubMed

Phillips, Austin; Kot, Mark

2015-11-01

Environmental changes are forcing many species to track suitable conditions or face extinction. In this study, we use a two-dimensional integrodifference equation to analyze whether a population can track a habitat that is moving due to climate change. We model habitat as a simple rectangle. Our model quickly leads to an eigenvalue problem that determines whether the population persists or declines. After surveying techniques to solve the eigenvalue problem, we highlight three findings that impact conservation efforts such as reserve design and species risk assessment. First, while other models focus on habitat length (parallel to the direction of habitat movement), we show that ignoring habitat width (perpendicular to habitat movement) can lead to overestimates of persistence. Dispersal barriers and hostile landscapes that constrain habitat width greatly decrease the population's ability to track its habitat. Second, for some long-distance dispersal kernels, increasing habitat length improves persistence without limit; for other kernels, increasing length is of limited help and has diminishing returns. Third, it is not always best to orient the long side of the habitat in the direction of climate change. Evidence suggests that the kurtosis of the dispersal kernel determines whether it is best to have a long, wide, or square habitat. In particular, populations with platykurtic dispersal benefit more from a wide habitat, while those with leptokurtic dispersal benefit more from a long habitat. We apply our model to the Rocky Mountain Apollo butterfly (Parnassius smintheus).

Visual Persistence and Information Pick-up in Learning Disabled Children.

ERIC Educational Resources Information Center

Mazer, Suzanne R.; And Others

1983-01-01

Two experiments tested possible explanations for previous research demonstrating lower span of apprehension for learning disabled students. In experiment 1, the length of visual persistence was less for LD subjects, while in experiment 2, the rate of information pick-up was slower for LD subjects. (CL)

Kinesin-5–dependent Poleward Flux and Spindle Length Control in Drosophila Embryo Mitosis

PubMed Central

Brust-Mascher, Ingrid; Sommi, Patrizia; Cheerambathur, Dhanya K.

2009-01-01

We used antibody microinjection and genetic manipulations to dissect the various roles of the homotetrameric kinesin-5, KLP61F, in astral, centrosome-controlled Drosophila embryo spindles and to test the hypothesis that it slides apart interpolar (ip) microtubules (MT), thereby controlling poleward flux and spindle length. In wild-type and Ncd null mutant embryos, anti-KLP61F dissociated the motor from spindles, producing a spatial gradient in the KLP61F content of different spindles, which was visible in KLP61F-GFP transgenic embryos. The resulting mitotic defects, supported by gene dosage experiments and time-lapse microscopy of living klp61f mutants, reveal that, after NEB, KLP61F drives persistent MT bundling and the outward sliding of antiparallel MTs, thereby contributing to several processes that all appear insensitive to cortical disruption. KLP61F activity contributes to the poleward flux of both ipMTs and kinetochore MTs and to the length of the metaphase spindle. KLP61F activity maintains the prometaphase spindle by antagonizing Ncd and another unknown force-generator and drives anaphase B, although the rate of spindle elongation is relatively insensitive to the motor's concentration. Finally, KLP61F activity contributes to normal chromosome congression, kinetochore spacing, and anaphase A rates. Thus, a KLP61F-driven sliding filament mechanism contributes to multiple aspects of mitosis in this system. PMID:19158379

PCB153 reduces telomerase activity and telomere length in immortalized human skin keratinocytes (HaCaT) but not in human foreskin keratinocytes (NFK)

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

Senthilkumar, P.K.; Robertson, L.W.; Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA

Polychlorinated biphenyls (PCBs), ubiquitous environmental pollutants, are characterized by long term-persistence in the environment, bioaccumulation, and biomagnification in the food chain. Exposure to PCBs may cause various diseases, affecting many cellular processes. Deregulation of the telomerase and the telomere complex leads to several biological disorders. We investigated the hypothesis that PCB153 modulates telomerase activity, telomeres and reactive oxygen species resulting in the deregulation of cell growth. Exponentially growing immortal human skin keratinocytes (HaCaT) and normal human foreskin keratinocytes (NFK) were incubated with PCB153 for 48 and 24 days, respectively, and telomerase activity, telomere length, superoxide level, cell growth, and cellmore » cycle distribution were determined. In HaCaT cells exposure to PCB153 significantly reduced telomerase activity, telomere length, cell growth and increased intracellular superoxide levels from day 6 to day 48, suggesting that superoxide may be one of the factors regulating telomerase activity, telomere length and cell growth compared to untreated control cells. Results with NFK cells showed no shortening of telomere length but reduced cell growth and increased superoxide levels in PCB153-treated cells compared to untreated controls. As expected, basal levels of telomerase activity were almost undetectable, which made a quantitative comparison of treated and control groups impossible. The significant down regulation of telomerase activity and reduction of telomere length by PCB153 in HaCaT cells suggest that any cell type with significant telomerase activity, like stem cells, may be at risk of premature telomere shortening with potential adverse health effects for the affected organism. -- Highlights: ► Human immortal (HaCaT) and primary (NFK) keratinocytes were exposed to PCB153. ► PCB153 significantly reduced telomerase activity and telomere length in HaCaT. ► No effect on telomere length and telomerase activity was found in NFK. ► Increased intracellular superoxide levels and reduced cell growth was seen in both. ► PCB153 may damage telomerase expressing cells like stem cells.« less

Experimental evidence for two thermodynamic length scales in neutralized polyacrylate gels

NASA Astrophysics Data System (ADS)

Horkay, Ferenc; Hecht, Anne-Marie; Grillo, Isabelle; Basser, Peter J.; Geissler, Erik

2002-11-01

The small angle neutron scattering (SANS) behavior of fully neutralized sodium polyacrylate gels is investigated in the presence of calcium ions. Analysis of the SANS response reveals the existence of three characteristic length scales, two of which are of thermodynamic origin, while the third length is associated with the frozen-in structural inhomogeneities. This latter contribution exhibits power law behavior with a slope of about -3.6, reflecting the presence of interfaces. The osmotically active component of the scattering signal is defined by two characteristic length scales, a correlation length ξ and a persistence length L.

Reducing SCADA System Nuisance Alarms in the Water Industry in Northern Ireland.

PubMed

O'Donoghue, Nigel; Phillips, Debra H; Nicell, Ciaran

2015-08-01

The advancement of telemetry control for the water industry has increased the difficulty of managing large volumes of nuisance alarms (i.e., alarms that do not require a response). The aim of this study was to identify and reduce the number of nuisance alarms that occur for Northern Ireland (NI) Water by carrying out alarm duration analysis to determine the appropriate length of persistence (an advanced alarm management tool) that could be applied. All data were extracted from TelemWeb (NI Water's telemetry monitoring system) and analyzed in Excel. Over a 6-week period, an average of 40 000 alarms occurred per week. The alarm duration analysis, which has never been implemented before by NI Water, found that an average of 57% of NI Water alarms had a duration of <5 minutes. Applying 5-minute persistence, therefore, could prevent an average 26 816 nuisance alarms per week. Most of these alarms were from wastewater assets.

The one-dimensional asymmetric persistent random walk

NASA Astrophysics Data System (ADS)

Rossetto, Vincent

2018-04-01

Persistent random walks are intermediate transport processes between a uniform rectilinear motion and a Brownian motion. They are formed by successive steps of random finite lengths and directions travelled at a fixed speed. The isotropic and symmetric 1D persistent random walk is governed by the telegrapher’s equation, also called the hyperbolic heat conduction equation. These equations have been designed to resolve the paradox of the infinite speed in the heat and diffusion equations. The finiteness of both the speed and the correlation length leads to several classes of random walks: Persistent random walk in one dimension can display anomalies that cannot arise for Brownian motion such as anisotropy and asymmetries. In this work we focus on the case where the mean free path is anisotropic, the only anomaly leading to a physics that is different from the telegrapher’s case. We derive exact expression of its Green’s function, for its scattering statistics and distribution of first-passage time at the origin. The phenomenology of the latter shows a transition for quantities like the escape probability and the residence time.

DNA-cisplatin binding mechanism peculiarities studied with single molecule stretching experiments

NASA Astrophysics Data System (ADS)

Crisafuli, F. A. P.; Cesconetto, E. C.; Ramos, E. B.; Rocha, M. S.

2012-02-01

We propose a method to determine the DNA-cisplatin binding mechanism peculiarities by monitoring the mechanical properties of these complexes. To accomplish this task, we have performed single molecule stretching experiments by using optical tweezers, from which the persistence and contour lengths of the complexes can be promptly measured. The persistence length of the complexes as a function of the drug total concentration in the sample was used to deduce the binding data, from which we show that cisplatin binds cooperatively to the DNA molecule, a point which so far has not been stressed in binding equilibrium studies of this ligand.

Lactation curves of dairy camels in an intensive system.

PubMed

Musaad, Abdelgadir; Faye, Bernard; Nikhela, Abdelmoneim Abu

2013-04-01

Weekly milk records of 47 she-camels in a multibreed dairy camel herd were collected for over a period of 5 years. A total of 72 lactation curves were defined, and relationships with parity, calving season, lactation length, milk production level, following lactations, and dam weight were analyzed. Overall mean values were milk yield up to 12 months, 1,970 ± 790 l; lactation length, 12.5 months; persistency, 94.7 %; weekly peak yield, 50.7 l; monthly peak yield, 220 ± 90 l; and the number of weeks to reach peak yield, 28. The highest productivity was recorded in summer with a weekly mean of 48.2 ± 19.4 l, compared with 34.1 ± 16.3 l in winter. The highest average yield recorded was for camels at sixth parity, whereas the highest weekly peak was at eighth parity, and highest persistency at fifth parity. Camels that calved during the cold months (November to February) were most productives, with the highest persistency, peak yield, and longest lactation length. Four types of curves were identified corresponding to different parities and milk yield levels. Based on these data, specific models for camels are proposed.

The Snakelike Chain Character of Unstructured RNA

PubMed Central

Jacobson, David R.; McIntosh, Dustin B.; Saleh, Omar A.

2013-01-01

In the absence of base-pairing and tertiary structure, ribonucleic acid (RNA) assumes a random-walk conformation, modulated by the electrostatic self-repulsion of the charged, flexible backbone. This behavior is often modeled as a Kratky-Porod “wormlike chain” (WLC) with a Barrat-Joanny scale-dependent persistence length. In this study we report measurements of the end-to-end extension of poly(U) RNA under 0.1 to 10 pN applied force and observe two distinct elastic-response regimes: a low-force, power-law regime characteristic of a chain of swollen blobs on long length scales and a high-force, salt-valence-dependent regime consistent with ion-stabilized crumpling on short length scales. This short-scale structure is additionally supported by force- and salt-dependent quantification of the RNA ion atmosphere composition, which shows that ions are liberated under stretching; the number of ions liberated increases with increasing bulk salt concentration. Both this result and the observation of two elastic-response regimes directly contradict the WLC model, which predicts a single elastic regime across all forces and, when accounting for scale-dependent persistence length, the opposite trend in ion release with salt concentration. We conclude that RNA is better described as a “snakelike chain,” characterized by smooth bending on long length scales and ion-stabilized crumpling on short length scales. In monovalent salt, these two regimes are separated by a characteristic length that scales with the Debye screening length, highlighting the determining importance of electrostatics in RNA conformation. PMID:24314087

Adsorption of finite semiflexible polymers and their loop and tail distributions

NASA Astrophysics Data System (ADS)

Kampmann, Tobias A.; Kierfeld, Jan

2017-07-01

We discuss the adsorption of semiflexible polymers to a planar attractive wall and focus on the questions of the adsorption threshold for polymers of finite length and their loop and tail distributions using both Monte Carlo simulations and analytical arguments. For the adsorption threshold, we find three regimes: (i) a flexible or Gaussian regime if the persistence length is smaller than the adsorption potential range, (ii) a semiflexible regime if the persistence length is larger than the potential range, and (iii) for finite polymers, a novel crossover to a rigid rod regime if the deflection length exceeds the contour length. In the flexible and semiflexible regimes, finite size corrections arise because the correlation length exceeds the contour length. In the rigid rod regime, however, it is essential how the global orientational or translational degrees of freedom are restricted by grafting or confinement. We discuss finite size corrections for polymers grafted to the adsorbing surface and for polymers confined by a second (parallel) hard wall. Based on these results, we obtain a method to analyze adsorption data for finite semiflexible polymers such as filamentous actin. For the loop and tail distributions, we find power laws with an exponential decay on length scales exceeding the correlation length. We derive and confirm the loop and tail power law exponents for flexible and semiflexible polymers. This allows us to explain that, close to the transition, semiflexible polymers have significantly smaller loops and both flexible and semiflexible polymers desorb by expanding their tail length. The tail distribution allows us to extract the free energy per length of adsorption for actin filaments from experimental data [D. Welch et al., Soft Matter 11, 7507 (2015)].

Titin PEVK segment: charge-driven elasticity of the open and flexible polyampholyte

PubMed Central

FORBES, JEFFREY G.; JIN, ALBERT J.; MA, KAN; GUTIERREZ-CRUZ, GUSTAVO; TSAI, WANXIA L.; WANG, KUAN

2015-01-01

The giant protein titin spans half of the sarcomere length and anchors the myosin thick filament to the Z-line of skeletal and cardiac muscles. The passive elasticity of muscle at a physiological range of stretch arises primarily from the extension of the PEVK segment, which is a polyampholyte with dense and alternating-charged clusters. Force spectroscopy studies of a 51 kDa fragment of the human fetal titin PEVK domain (TP1) revealed that when charge interactions were reduced by raising the ionic strength from 35 to 560 mM, its mean persistence length increased from 0.30±0.04 nm to 0.60±0.07 nm. In contrast, when the secondary structure of TP1 was altered drastically by the presence of 40 and 80% (v/v) of trifluoroethanol, its force-extension behavior showed no significant shift in the mean persistence length of ~0.18±0.03 nm at the ionic strength of 15 mM. Additionally, the mean persistence length also increased from 0.29 to 0.41 nm with increasing calcium concentration from pCa 5–8 to pCa 3–4. We propose that PEVK is not a simple entropic spring as is commonly assumed, but a highly evolved, gel-like enthalpic spring with its elasticity dominated by the sequence-specific charge interactions. A single polyampholyte chain may be fine-tuned to generate a broad range of molecular elasticity by varying charge pairing schemes and chain configurations. PMID:16465472

Thermodynamic confinement and alpha-helix persistence length in poly(gamma-benzyl-L-glutamate)-b-poly(dimethyl siloxane)-b-poly(gamma-benzyl-L-glutamate) triblock copolymers.

PubMed

Papadopoulos, P; Floudas, G; Schnell, I; Lieberwirth, I; Nguyen, T Q; Klok, H-A

2006-02-01

The structure and the associated dynamics of a series of poly(gamma-benzyl-L-glutamate)-b-poly(dimethyl siloxane)-b-poly(gamma-benzyl-L-glutamate) (PBLG-b-PDMS-b-PBLG) triblock copolymers were investigated using small- and wide-angle X-ray scattering, NMR, transmission electron microscopy, and dielectric spectroscopy, respectively. The structural analysis revealed phase separation in the case of the longer blocks with defected alpha-helical segments embedded within the block copolymer nanodomains. The alpha-helical persistence length was found to depend on the degree of segregation; thermodynamic confinement and chain stretching results in the partial annihilation of helical defects.

Overexpression of TIMP-3 in Chondrocytes Produces Transient Reduction in Growth Plate Length but Permanently Reduces Adult Bone Quality and Quantity

PubMed Central

Plumb, Darren; Vo, Phoung; Shah, Mittal; Staines, Katherine; Sampson, Alexandra; Shefelbine, Sandra; Pitsillides, Andrew A.; Bou-Gharios, George

2016-01-01

Bone development and length relies on the growth plate formation, which is dependent on degradative enzymes such as MMPs. Indeed, deletion of specific members of this enzyme family in mice results in important joint and bone abnormalities, suggesting a role in skeletal development. As such, the control of MMP activity is vital in the complex process of bone formation and growth. We generated a transgenic mouse line to overexpress TIMP3 in mouse chondrocytes using the Col2a1-chondrocyte promoter. This overexpression in cartilage resulted in a transient shortening of growth plate in homozygote mice but bone length was restored at eight weeks of age. However, tibial bone structure and mechanical properties remained compromised. Despite no transgene expression in adult osteoblasts from transgenic mice in vitro, their differentiation capacity was decreased. Neonates, however, did show transgene expression in a subset of bone cells. Our data demonstrate for the first time that transgene function persists in the chondro-osseous lineage continuum and exert influence upon bone quantity and quality. PMID:28002442

Influence of Stress and Antibiotic Resistance on Cell-Length Distribution in Mycobacterium tuberculosis Clinical Isolates

PubMed Central

Vijay, Srinivasan; Vinh, Dao N.; Hai, Hoang T.; Ha, Vu T. N.; Dung, Vu T. M.; Dinh, Tran D.; Nhung, Hoang N.; Tram, Trinh T. B.; Aldridge, Bree B.; Hanh, Nguyen T.; Thu, Do D. A.; Phu, Nguyen H.; Thwaites, Guy E.; Thuong, Nguyen T. T.

2017-01-01

Mycobacterial cellular variations in growth and division increase heterogeneity in cell length, possibly contributing to cell-to-cell variation in host and antibiotic stress tolerance. This may be one of the factors influencing Mycobacterium tuberculosis persistence to antibiotics. Tuberculosis (TB) is a major public health problem in developing countries, antibiotic persistence, and emergence of antibiotic resistance further complicates this problem. We wanted to investigate the factors influencing cell-length distribution in clinical M. tuberculosis strains. In parallel we examined M. tuberculosis cell-length distribution in a large set of clinical strains (n = 158) from ex vivo sputum samples, in vitro macrophage models, and in vitro cultures. Our aim was to understand the influence of clinically relevant factors such as host stresses, M. tuberculosis lineages, antibiotic resistance, antibiotic concentrations, and disease severity on the cell size distribution in clinical M. tuberculosis strains. Increased cell size and cell-to-cell variation in cell length were associated with bacteria in sputum and infected macrophages rather than liquid culture. Multidrug-resistant (MDR) strains displayed increased cell length heterogeneity compared to sensitive strains in infected macrophages and also during growth under rifampicin (RIF) treatment. Importantly, increased cell length was also associated with pulmonary TB disease severity. Supporting these findings, individual host stresses, such as oxidative stress and iron deficiency, increased cell-length heterogeneity of M. tuberculosis strains. In addition we also observed synergism between host stress and RIF treatment in increasing cell length in MDR-TB strains. This study has identified some clinical factors contributing to cell-length heterogeneity in clinical M. tuberculosis strains. The role of these cellular adaptations to host and antibiotic tolerance needs further investigation. PMID:29209302

Genetic Predisposition to Persistent Apical Periodontitis

PubMed Central

Morsani, Jussara M.; Aminoshariae, Anita; Han, Yiping Weng; Montagnese, Thomas A.; Mickel, Andre

2013-01-01

Introduction The proinflammatory cytokine interleukin (IL)-1 is a key regulator of host responses to microbial infection and a major modulator of extracellular matrix catabolism and bone resorption. Allele2 of IL-1b is associated with a four-fold increase in IL-1β production. The aim of this case-control study was to evaluate the gene polymorphism of IL-1β in the pathogenesis of endodontic failure. We hypothesized that the gene polymorphism (allele2 of IL-1β) would influence host response and enhance inflammatory reactions predisposing to persistent apical periodontitis (PAP). Materials and Methods Subjects with at least 1 year of follow-up after root canal therapy (RCT) were recalled. Inclusion and exclusion criteria were applied, and 34 subjects with signs/symptoms of PAP with otherwise acceptable RCT were included. Sixty-one controls showed healing with acceptable RCT. Genomic DNA from buccal mucosa was amplified by polymerase chain reaction followed by restriction fragment length polymorphism to distinguish the alleles of IL-1β gene polymorphism. Results A significant difference in the distribution of the polymorphic genotype among cases (70.6%) and controls (24.6%) (P < .001, Pearson χ2) was shown. Conclusions These findings suggest that specific genetic markers associated with increased IL-1β production may contribute to increased susceptibility to PAP. PMID:21419289

Controls on streamflow intermittence in the Colorado Front Range

NASA Astrophysics Data System (ADS)

Kampf, S. K.; Puntenney, K.; Martin, C.; Weber, R.; Gerlich, J.; Hammond, J. C.; Lefsky, M. A.

2017-12-01

Intermittent streams comprise more than 60% of the channel length in semiarid northern Colorado, yet little is known about their flow magnitude and timing. We used field surveys, stream sensors, and remote sensing to quantify spatial and temporal patterns of streamflow intermittence in the Cache la Poudre basin in 2016-2017. To evaluate potential controls on streamflow intermittence, we delineated the drainage area to each monitored point and quantified the catchment's mean precipitation, temperature, snow persistence, slope, aspect, vegetation type, soil type, and bedrock geology. During the period of study, most streams below 2500 m elevation and <550 mm mean annual precipitation were intermittent, with flow only during the early spring and summer. In these drier low elevation areas, flow duration generally increased with precipitation and snow persistence. Locally, the type of bedrock geology and location of streams relative to faults affected flow duration. Above 2500 m, nearly all streams with drainage areas >1 km2 had perennial flow, whereas nearly all streams with drainage areas <1 km2 had intermittent flow. For the high elevation intermittent streams, stream locations often differed substantially from the locations mapped in standard GIS data products. Initial analyses have identified no clearly quantifiable controls on flow duration of high elevation streams, but field observations indicate subsurface flow paths are important contributors to surface streams.

A Lag in Speech Motor Coordination During Sentence Production Is Associated With Stuttering Persistence in Young Children

PubMed Central

Smith, Anne; Weber, Christine

2017-01-01

Purpose The purpose of this study was to determine if indices of speech motor coordination during the production of sentences varying in sentence length and syntactic complexity were associated with stuttering persistence versus recovery in 5- to 7-year-old children. Methods We compared children with persistent stuttering (CWS-Per) with children who had recovered (CWS-Rec), and children who do not stutter (CWNS). A kinematic measure of articulatory coordination, lip aperture variability (LAVar), and overall movement duration were computed for perceptually fluent sentence productions varying in length and syntactic complexity. Results CWS-Per exhibited higher LAVar across sentence types compared to CWS-Rec and CWNS. For the participants who successfully completed the experimental paradigm, the demands of increasing sentence length and syntactic complexity did not appear to disproportionately affect the speech motor coordination of CWS-Per compared to their recovered and fluent peers. However, a subset of CWS-Per failed to produce the required number of accurate utterances. Conclusions These findings support our hypothesis that the speech motor coordination of school-age CWS-Per, on average, is less refined and less mature compared to CWS-Rec and CWNS. Childhood recovery from stuttering is characterized, in part, by overcoming an earlier occurring maturational lag in speech motor development. PMID:28056137

Softening of the stiffness of bottle-brush polymers by mutual interaction

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

Bolisetty, S.; Airaud, C.; Rosenfeldt, S.

2007-04-15

We study bottle-brush macromolecules in a good solvent by small-angle neutron scattering (SANS), static light scattering (SLS), and dynamic light scattering (DLS). These polymers consist of a linear backbone to which long side chains are chemically grafted. The backbone contains about 1600 monomer units (weight average) and every second monomer unit carries side chains with approximately 60 monomer units. The SLS and SANS data extrapolated to infinite dilution lead to the form factor of the polymer that can be described in terms of a wormlike chain with a contour length of 380 nm and a persistence length of 17.5 nm.more » An analysis of the DLS data confirms these model parameters. The scattering intensities taken at finite concentration can be modeled using the polymer reference interaction site model. It reveals a softening of the bottle-brush polymers caused by their mutual interaction. We demonstrate that the persistence decreases from 17.5 nm down to 5 nm upon increasing the concentration from dilute solution to the highest concentration (40.59 g/l) under consideration. The observed softening of the chains is comparable to the theoretically predicted decrease of the electrostatic persistence length of linear polyelectrolyte chains at finite concentrations.« less

Infertility associated with persistent hymen in an alpaca and a llama

PubMed Central

Tan, Rachel H.H.; Dascanio, John J.

2008-01-01

Perforation and dilation of the persistent hymen in an alpaca and a llama, detected by vaginal examination and endoscopy, was achieved by use of a sigmoidoscope and incremental dilation using cylindrical instruments to a maximum diameter of 38 mm. Outcome and subsequent fertility are dependent on length of time the obstruction has been present and secondary uterine disease. PMID:19183735

Prevention of Postoperative Bile Leak in Partial Cystectomy for Hydatid Liver Disease: Tricks of the Trade.

PubMed

Peker, Kivanc Derya; Gumusoglu, Alpen Yahya; Seyit, Hakan; Kabuli, Hamit Ahmet; Salik, Aysun Erbahceci; Gonenc, Murat; Kapan, Selin; Alis, Halil

2015-12-01

The presence of postoperative bile leak is the major outcome measure for the assessment of operative success in partial cystectomy for hydatid liver disease. However, the optimal operative strategy to reduce the postoperative bile leak rate is yet to be defined. Medical records of patients who underwent partial cystectomy for hydatid liver disease between January 2013 and January 2015 were reviewed in this retrospective analysis. All patients were managed with a specific operative protocol. The primary outcome measure was the rate of persistent postoperative bile leak. The secondary outcome measures were the morbidity and mortality rate, and the length of hospital stay. Twenty-eight patients were included in the study. Only one patient (3.6 %) developed persistent postoperative bile leak. The overall morbidity and mortality rate was 17.8 and 0 %, respectively. The median length of hospital stay was 5 days. Aggressive preventative surgical measures have led to low persistent bile leak rates with low morbidity and mortality.

Fault segmentation: New concepts from the Wasatch Fault Zone, Utah, USA

USGS Publications Warehouse

Duross, Christopher; Personius, Stephen F.; Crone, Anthony J.; Olig, Susan S.; Hylland, Michael D.; Lund, William R.; Schwartz, David P.

2016-01-01

The question of whether structural segment boundaries along multisegment normal faults such as the Wasatch fault zone (WFZ) act as persistent barriers to rupture is critical to seismic hazard analyses. We synthesized late Holocene paleoseismic data from 20 trench sites along the central WFZ to evaluate earthquake rupture length and fault segmentation. For the youngest (<3 ka) and best-constrained earthquakes, differences in earthquake timing across prominent primary segment boundaries, especially for the most recent earthquakes on the north-central WFZ, are consistent with segment-controlled ruptures. However, broadly constrained earthquake times, dissimilar event times along the segments, the presence of smaller-scale (subsegment) boundaries, and areas of complex faulting permit partial-segment and multisegment (e.g., spillover) ruptures that are shorter (~20–40 km) or longer (~60–100 km) than the primary segment lengths (35–59 km). We report a segmented WFZ model that includes 24 earthquakes since ~7 ka and yields mean estimates of recurrence (1.1–1.3 kyr) and vertical slip rate (1.3–2.0 mm/yr) for the segments. However, additional rupture scenarios that include segment boundary spatial uncertainties, floating earthquakes, and multisegment ruptures are necessary to fully address epistemic uncertainties in rupture length. We compare the central WFZ to paleoseismic and historical surface ruptures in the Basin and Range Province and central Italian Apennines and conclude that displacement profiles have limited value for assessing the persistence of segment boundaries but can aid in interpreting prehistoric spillover ruptures. Our comparison also suggests that the probabilities of shorter and longer ruptures on the WFZ need to be investigated.

Should Roux-en-Y gastric bypass biliopancreatic limb length be tailored to achieve improved diabetes outcomes?

PubMed

Nora, Mário; Morais, Tiago; Almeida, Rui; Guimarães, Marta; Monteiro, Mariana P

2017-12-01

The objective is to access the role of Roux-en-Y gastric bypass (RYGB) biliopancreatic limb (BPL) length in type 2 diabetes (T2D) outcomes.RYGB is more effective than medical intervention for T2D treatment in obese patients. Despite the scarcity of available data, previous reports suggest that modifications of the RYGB limb lengths could improve the antidiabetic effects of the surgery.A cohort of obese T2D patients (n = 114) were submitted to laparoscopic RYGB, either with a standard BPL (SBPL) (n = 41; BPL 84 ± 2 cm) or long BPL (LBPL) (n = 73; BPL = 200 cm) and routinely monitored for weight loss and diabetic status up to 5 years after surgery.Baseline clinical features in the 2 patient subgroups were similar. After surgery, there was a significant reduction of body mass index (BMI) in both the groups, although the percentage of excess BMI loss (%EBMIL) after 5 years was higher for LBPL (75.50 ± 2.63 LBPL vs 65.90 ± 3.61 SBPL, P = .04). T2D remission rate was also higher (73% vs 55%, P < .05), while disease relapse rate (13.0% vs 32.5%; P < .05) and antidiabetic drug requirement in patients with persistent diabetes were lower after LBPL. Preoperative T2D duration predicted disease remission, but only for SBPL.RYGB with a longer BPL improves %EBMIL, T2D remission, and glycemic control in those with persistent disease, while it decreases diabetes relapse rate over time. The antidiabetic effects of LBPL RYGB also are less influenced by the preoperative disease duration. These data suggest the RYGB procedure could be tailored to improve T2D outcomes.

The snakelike chain character of unstructured RNA.

PubMed

Jacobson, David R; McIntosh, Dustin B; Saleh, Omar A

2013-12-03

In the absence of base-pairing and tertiary structure, ribonucleic acid (RNA) assumes a random-walk conformation, modulated by the electrostatic self-repulsion of the charged, flexible backbone. This behavior is often modeled as a Kratky-Porod "wormlike chain" (WLC) with a Barrat-Joanny scale-dependent persistence length. In this study we report measurements of the end-to-end extension of poly(U) RNA under 0.1 to 10 pN applied force and observe two distinct elastic-response regimes: a low-force, power-law regime characteristic of a chain of swollen blobs on long length scales and a high-force, salt-valence-dependent regime consistent with ion-stabilized crumpling on short length scales. This short-scale structure is additionally supported by force- and salt-dependent quantification of the RNA ion atmosphere composition, which shows that ions are liberated under stretching; the number of ions liberated increases with increasing bulk salt concentration. Both this result and the observation of two elastic-response regimes directly contradict the WLC model, which predicts a single elastic regime across all forces and, when accounting for scale-dependent persistence length, the opposite trend in ion release with salt concentration. We conclude that RNA is better described as a "snakelike chain," characterized by smooth bending on long length scales and ion-stabilized crumpling on short length scales. In monovalent salt, these two regimes are separated by a characteristic length that scales with the Debye screening length, highlighting the determining importance of electrostatics in RNA conformation. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

The Statistical Segment Length of DNA: Opportunities for Biomechanical Modeling in Polymer Physics and Next-Generation Genomics.

PubMed

Dorfman, Kevin D

2018-02-01

The development of bright bisintercalating dyes for deoxyribonucleic acid (DNA) in the 1990s, most notably YOYO-1, revolutionized the field of polymer physics in the ensuing years. These dyes, in conjunction with modern molecular biology techniques, permit the facile observation of polymer dynamics via fluorescence microscopy and thus direct tests of different theories of polymer dynamics. At the same time, they have played a key role in advancing an emerging next-generation method known as genome mapping in nanochannels. The effect of intercalation on the bending energy of DNA as embodied by a change in its statistical segment length (or, alternatively, its persistence length) has been the subject of significant controversy. The precise value of the statistical segment length is critical for the proper interpretation of polymer physics experiments and controls the phenomena underlying the aforementioned genomics technology. In this perspective, we briefly review the model of DNA as a wormlike chain and a trio of methods (light scattering, optical or magnetic tweezers, and atomic force microscopy (AFM)) that have been used to determine the statistical segment length of DNA. We then outline the disagreement in the literature over the role of bisintercalation on the bending energy of DNA, and how a multiscale biomechanical approach could provide an important model for this scientifically and technologically relevant problem.

Multiscale Modelling for investigating single molecule effects on the mechanics of actin filaments

NASA Astrophysics Data System (ADS)

A, Deriu Marco; C, Bidone Tamara; Laura, Carbone; Cristina, Bignardi; M, Montevecchi Franco; Umberto, Morbiducci

2011-12-01

This work presents a preliminary multiscale computational investigation of the effects of nucleotides and cations on the mechanics of actin filaments (F-actin). At the molecular level, Molecular Dynamics (MD) simulations are employed to characterize the rearrangements of the actin monomers (G-actin) in terms of secondary structures evolution in physiological conditions. At the mesoscale level, a coarse grain (CG) procedure is adopted where each monomer is represented by means of Elastic Network Modeling (ENM) technique. At the macroscale level, actin filaments up to hundreds of nanometers are assumed as isotropic and elastic beams and characterized via Rotation Translation Block (RTB) analysis. F-actin bound to adenosine triphosphate (ATP) shows a persistence length around 5 μm, while actin filaments bound to adenosine diphosphate (ADP) have a persistence length of about 3 μm. With magnesium bound to the high affinity binding site of G-actin, the persistence length of F-actin decreases to about 2 μm only in the ADP-bound form of the filament, while the same ion has no effects, in terms of stiffness variation, on the ATP-bound form of F-actin. The molecular mechanisms behind these changes in flexibility are herein elucidated. Thus, this study allows to analyze how the local binding of cations and nucleotides on G-actin induce molecular rearrangements that transmit to the overall F-actin, characterizing shifts of mechanical properties, that can be related with physiological and pathological cellular phenomena, as cell migration and spreading. Further, this study provides the basis for upcoming investigating of network and cellular remodelling at higher length scales.

Allelopathic Effects of Litter Axonopus compressus against Two Weedy Species and Its Persistence in Soil

PubMed Central

Samedani, B.; Juraimi, A. S.; Rafii, M. Y.; Anuar, A. R.; Sheikh Awadz, S. A.; Anwar, M. P.

2013-01-01

This study investigated the allelopathic effect of Axonopus compressus litter on Asystasia gangetica and Pennisetum polystachion. In experiment 1 the bioassays with 0, 10, 30, and 50 g L−1 of aqueous A. compressus litter leachate were conducted. Experiment 2 was carried out by incorporating 0, 10, 20, 30, 40, and 50 g L−1 of A. compressus litter leachate into soil. In experiment 3, the fate of A. compressus litter leachate phenolics in the soil was investigated. A. compressus leachates did not affect the germination percentage of A. gangetica and P. polystachion, but delayed germination of A. gangetica seeds and decreased seed germination time of P. polystachion. A. compressus litter leachates affected weeds hypocotyl length. Hypocotyl length reductions of 18 and 31% were observed at the highest concentration (50 g L−1) compared to the control in A. gangetica and P. polystachion, respectively. When concentration of A. compressus litter leachate-amended soil increased A. gangetica and P. polystachion seedling shoot length, root length, seedling weight and chlorophyll concentration were not affected. The 5-week decomposition study of A. compressus showed that the phenolic compounds in A. compressus litter abruptly decreased about 52% after two weeks and remained steady until the end of the incubation. PMID:24260020

Monte Carlo simulations of lattice models for single polymer systems

NASA Astrophysics Data System (ADS)

Hsu, Hsiao-Ping

2014-10-01

Single linear polymer chains in dilute solutions under good solvent conditions are studied by Monte Carlo simulations with the pruned-enriched Rosenbluth method up to the chain length N ˜ O(10^4). Based on the standard simple cubic lattice model (SCLM) with fixed bond length and the bond fluctuation model (BFM) with bond lengths in a range between 2 and sqrt{10}, we investigate the conformations of polymer chains described by self-avoiding walks on the simple cubic lattice, and by random walks and non-reversible random walks in the absence of excluded volume interactions. In addition to flexible chains, we also extend our study to semiflexible chains for different stiffness controlled by a bending potential. The persistence lengths of chains extracted from the orientational correlations are estimated for all cases. We show that chains based on the BFM are more flexible than those based on the SCLM for a fixed bending energy. The microscopic differences between these two lattice models are discussed and the theoretical predictions of scaling laws given in the literature are checked and verified. Our simulations clarify that a different mapping ratio between the coarse-grained models and the atomistically realistic description of polymers is required in a coarse-graining approach due to the different crossovers to the asymptotic behavior.

Allelopathic effects of litter Axonopus compressus against two weedy species and its persistence in soil.

PubMed

Samedani, B; Juraimi, A S; Rafii, M Y; Anuar, A R; Sheikh Awadz, S A; Anwar, M P

2013-01-01

This study investigated the allelopathic effect of Axonopus compressus litter on Asystasia gangetica and Pennisetum polystachion. In experiment 1 the bioassays with 0, 10, 30, and 50 g L⁻¹ of aqueous A. compressus litter leachate were conducted. Experiment 2 was carried out by incorporating 0, 10, 20, 30, 40, and 50 g L⁻¹ of A. compressus litter leachate into soil. In experiment 3, the fate of A. compressus litter leachate phenolics in the soil was investigated. A. compressus leachates did not affect the germination percentage of A. gangetica and P. polystachion, but delayed germination of A. gangetica seeds and decreased seed germination time of P. polystachion. A. compressus litter leachates affected weeds hypocotyl length. Hypocotyl length reductions of 18 and 31% were observed at the highest concentration (50 g L⁻¹) compared to the control in A. gangetica and P. polystachion, respectively. When concentration of A. compressus litter leachate-amended soil increased A. gangetica and P. polystachion seedling shoot length, root length, seedling weight and chlorophyll concentration were not affected. The 5-week decomposition study of A. compressus showed that the phenolic compounds in A. compressus litter abruptly decreased about 52% after two weeks and remained steady until the end of the incubation.

Persistent shoreline shape induced from offshore geologic framework: Effects of shoreface connected ridges

USGS Publications Warehouse

Safak, Ilgar; List, Jeffrey; Warner, John C.; Schwab, William C.

2017-01-01

Mechanisms relating offshore geologic framework to shoreline evolution are determined through geologic investigations, oceanographic deployments, and numerical modeling. Analysis of shoreline positions from the past 50 years along Fire Island, New York, a 50 km long barrier island, demonstrates a persistent undulating shape along the western half of the island. The shelf offshore of these persistent undulations is characterized with shoreface-connected sand ridges (SFCR) of a similar alongshore length scale, leading to a hypothesis that the ridges control the shoreline shape through the modification of flow. To evaluate this, a hydrodynamic model was configured to start with the US East Coast and scale down to resolve the Fire Island nearshore. The model was validated using observations along western Fire Island and buoy data, and used to compute waves, currents and sediment fluxes. To isolate the influence of the SFCR on the generation of the persistent shoreline shape, simulations were performed with a linearized nearshore bathymetry to remove alongshore transport gradients associated with shoreline shape. The model accurately predicts the scale and variation of the alongshore transport that would generate the persistent shoreline undulations. In one location, however, the ridge crest connects to the nearshore and leads to an offshore-directed transport that produces a difference in the shoreline shape. This qualitatively supports the hypothesized effect of cross-shore fluxes on coastal evolution. Alongshore flows in the nearshore during a representative storm are driven by wave breaking, vortex force, advection and pressure gradient, all of which are affected by the SFCR.

Nanomechanics of Pectin-Linked β-Lactoglobulin Nanofibril Bundles.

PubMed

Loveday, Simon M; Gunning, A Patrick

2018-06-14

Nanofibrils of β-lactoglobulin can be assembled into bundles by site-specific noncovalent cross-linking with high-methoxyl pectin (Hettiarachchi et al. Soft Matter 2016, 12, 756). Here we characterized the nanomechanical properties of bundles using atomic force microscopy and force spectroscopy. Bundles had Gaussian cross sections and a mean height of 17.4 ± 1.4 nm. Persistence lengths were calculated using image analysis with the mean-squared end-to-end model. The relationship between the persistence length and the thickness had exponents of 1.69-2.30, which is consistent with previous reports for other fibril types. In force spectroscopy experiments, the bundles stretched in a qualitatively different manner to fibrils, and some of the force curves were consistent with peeling fibrils away from bundles. The flexibility of pectin-linked nanofibril bundles is likely to be tunable by modulating the stiffness and length of fibrils and the ratio of pectin to fibrils, giving rise to a wide range of structures and functionalities.

Anterior cruciate ligament allograft transplantation in dogs.

PubMed

Vasseur, P B; Stevenson, S; Gregory, C R; Rodrigo, J J; Pauli, S; Heitter, D; Sharkey, N

1991-08-01

The biomechanical and clinical performance of bone-ligament-bone anterior cruciate ligament (ACL) allografts was studied in eight dogs. Allografts were collected from skeletally mature, healthy dogs using aseptic technique, and stored at -70 degrees for three to five weeks before implantation. The allografts were size-matched to the recipient dogs using ACL length and then rigidly fixed in position with interference screws and Kirschner wires. Three dogs regained a normal gait, and their grafts sustained breaking loads that were 25%, 41%, and 59% of controls. Partial or complete graft failure occurred in the other five dogs at some point in the study. Four had intraligamentous rupture and one had an avulsion fracture of the femoral attachment site. Joint-fluid cytology was normal in all eight dogs. Histologic examination showed persistent lymphoplasmacytic infiltrate. Eventually the allograft cores were incorporated in the host bed. Hyperplasia and fibrosis of the synovial membrane were diffuse and persisted as focal accumulations of mononuclear inflammatory cells.

Prolonged persistent patent ductus arteriosus: potential perdurable anomalies in premature infants.

PubMed

Saldeño, Y P; Favareto, V; Mirpuri, J

2012-12-01

Patent ductus arteriosus (PDA) is a common condition among preterm infants. Controversy exists regarding the risk-benefit ratio of early closure of PDAs by either medical or surgical treatments. On the other hand, potential morbidities associated with no or delayed closure has not been well studied. The objective of the study was to determine if there is an association of prolonged persistent PDA (PP-PDA) with various morbidities in infants ≤28 weeks or 1250 g. This matched case-control analysis includes preterm infants with a diagnosis of PDA over a period of 28 months in a single level III center in the USA. The predictive variable was the presence of a PP-PDA (PDA>3 weeks). Cases were infants with PP-PDA and controls were those with PDA but not PP-PDA (two controls for each case). Outcome variables included days on mechanical ventilation and with oxygen treatment, length of hospital stay, bronchopulmonary dysplasia (BPD), retinopathy of prematurity stage III-V (ROP) necrotizing enterocolitis grade II or more (NEC), delayed growth, direct hyperbilirubinemia >4 mg dl(-1) and osteopenia of prematurity. Data was obtained from database collected prospectively and from the review of clinical records when necessary. Statistics included ANOVA, Kaplan-Meier curves and χ (2). Significance was set at P<0.05. PP-PDA was associated with a significant increase in the number of days of mechanical ventilation, oxygen treatment and length of hospital stay, and in the rates of BPD (60% vs 4.5%), NEC (29% vs 5%), ROP (43% vs 5%), direct hyperbilirubinemia (41% vs 3%), osteopenia (44% vs 6%), parenteral nutrition for >40 days (70% vs 21%), tracheostomy during the hospitalization (15% vs 0%) and delayed growth (70% vs 21%), were also significantly higher in babies with PP-PDA. A prolonged exposure to PDA does not seem to be inconsequential for some infants and is associated with an increase prevalence of severe morbidities with potential long lasting effects.

Testing a model of componential processing of multi-symbol numbers-evidence from measurement units.

PubMed

Huber, Stefan; Bahnmueller, Julia; Klein, Elise; Moeller, Korbinian

2015-10-01

Research on numerical cognition has addressed the processing of nonsymbolic quantities and symbolic digits extensively. However, magnitude processing of measurement units is still a neglected topic in numerical cognition research. Hence, we investigated the processing of measurement units to evaluate whether typical effects of multi-digit number processing such as the compatibility effect, the string length congruity effect, and the distance effect are also present for measurement units. In three experiments, participants had to single out the larger one of two physical quantities (e.g., lengths). In Experiment 1, the compatibility of number and measurement unit (compatible: 3 mm_6 cm with 3 < 6 and mm < cm; incompatible: 3 cm_6 mm with 3 < 6 but cm > mm) as well as string length congruity (congruent: 1 m_2 km with m < km and 2 < 3 characters; incongruent: 2 mm_1 m with mm < m, but 3 > 2 characters) were manipulated. We observed reliable compatibility effects with prolonged reaction times (RT) for incompatible trials. Moreover, a string length congruity effect was present in RT with longer RT for incongruent trials. Experiments 2 and 3 served as control experiments showing that compatibility effects persist when controlling for holistic distance and that a distance effect for measurement units exists. Our findings indicate that numbers and measurement units are processed in a componential manner and thus highlight that processing characteristics of multi-digit numbers generalize to measurement units. Thereby, our data lend further support to the recently proposed generalized model of componential multi-symbol number processing.

Does behaviour modification affect post-stroke risk factor control? Three-year follow-up of a randomized controlled trial.

PubMed

McManus, Julie Ann; Craig, Alison; McAlpine, Christine; Langhorne, Peter; Ellis, Graham

2009-02-01

Little is known about the long-term effectiveness after stroke of interventions for behaviour modification and ensuring concordance with therapies. We describe a follow-up study of a previous randomized controlled trial of a brief period of behaviour modification. The aim of this study was to determine outcomes three years after the initial intervention. Survivors of the original cohort were contacted and asked to attend for follow-up interview, within a geriatric day hospital. This study was carried out in the Geriatric Day Hospital at Stobhill Hospital, Balornock Road, Glasgow. Details of risk factor control, including blood pressure, cholesterol levels and diabetic control, were assessed. Questionnaires used in the initial study were repeated including the Geriatric Depression Scale score, Euroqol Perceived Health Status and Stroke Services Satisfaction Questionnaire. Primary outcome was collective risk factor control. Clinical outcomes including recurrent cerebrovascular events, medication persistence and perceived health status were also recorded. Mean length of follow-up was 3.6 years (SD 0.43). Of the 205 patients enrolled in the initial study, 102 patients attended for repeat interview(49 intervention/53 control). There were no significant differences in the percentage of controlled risk factors between groups (intervention 51.7% versus control 55.9%, P = 0.53). Similarities were observed in the number of recurrent clinical events and medication persistence between groups. No overall difference was observed in perceived health status, satisfaction with care or depression scores. Brief intervention with respect to behaviour modification and risk factor control does not appear to have any long-term benefit. These results must be cautiously interpreted in light of the small study number and further research is required.

Visibility and Persistence of Marker Dyes and Effect on the Quality and Mating Competitiveness of Mass-Reared Flies (Diptera: Tephritidae): Anastrepha obliqua and Bisexual and Genetic Sexing (Tapachula-7) Strains of A. ludens.

PubMed

Arredondo, José; Ruiz, Lia; López, Gladis; Díaz-Fleischer, Francisco

2017-08-01

Fluorescent dyes are commonly used in the sterile insect technique (SIT) for marking insects for a proper identification after recapture. However, the quality of the mark must be balanced against insect performance, because dyes can negatively affect some parameters of insect performance and reduce their effectiveness in control with the SIT. We determined the visibility and persistence and the effect of dyes on the quality of Anastrepha obliqua (Macquart) and Anastrepha ludens (Loew) (bisexual and genetic sexing strains) by testing four concentrations of a dye (Day-Glo) from 0 to 2.5 g dye/kg of pupae. Visibility and persistence of the mark were positively affected by dose and negatively affected by the length of time the samples were kept in a solution of 75% alcohol. However, upon dissection, even the lowest dose of dye was visible under a fluorescence microscope. Between dyed and undyed pupae (control), no significant differences were observed in rates of emergence, fliers and flight ability, and survival in two tests, with water and without food and without water and food, at any of the concentrations tested. Furthermore, no significant difference in mating competitiveness was detected between control pupae and those dyed at 1.0 and 2.5 g dye/kg pupae. We discuss our results with the possibility of reducing the dose of dye in these three flies, because the heads are large enough to capture sufficient particles to permit identification with the current methods of detection. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Birth month associations with height, head circumference, and limb lengths among Peruvian children.

PubMed

Pomeroy, Emma; Wells, Jonathan C K; Stanojevic, Sanja; Miranda, J Jaime; Cole, Tim J; Stock, Jay T

2014-05-01

Associations between season of birth and body size, morbidity, and mortality have been widely documented, but it is unclear whether different parts of the body are differentially sensitive, and if such effects persist through childhood. This may be relevant to understanding the relationship between early life environment and body size and proportions. We investigated associations between birth month and anthropometry among rural highland (n = 162) and urban lowland (n = 184) Peruvian children aged 6 months to 8 years. Stature; head-trunk height; total limb, ulna, tibia, hand, and foot lengths; head circumference; and limb measurements relative to head-trunk height were converted to internal age-sex-specific z scores. Lowland and highland datasets were then analyzed separately for birth month trends using cosinor analysis, as urban conditions likely provide a more consistent environment compared with anticipated seasonal variation in the rural highlands. Among highland children birth month associations were significant most strongly for tibia length, followed by total lower limb length and stature, with a peak among November births. Results were not significant for other measurements or among lowland children. The results suggest a prenatal or early postnatal environmental effect on growth that is more marked in limb lengths than trunk length or head size, and persists across the age range studied. We suggest that the results may reflect seasonal variation in maternal nutrition in the rural highlands, but other hypotheses such as variation in maternal vitamin D levels cannot be excluded. Copyright © 2014 Wiley Periodicals, Inc.

Age-related differences in dynamic balance control during stair descent and effect of varying step geometry.

PubMed

Novak, A C; Komisar, V; Maki, B E; Fernie, G R

2016-01-01

The incidence of stairway falls and related injuries remains persistently high; however, the risk of stair injuries could be reduced through improved stairway design. The current study investigated dynamic balance control during stair descent and the effects of varying the step geometry. Data were collected from 20 healthy young and 20 older adults as they descended three staircases (riser heights of 7, 7.5 and 8 inches (178, 190 and 203 mm, respectively)). At each riser height, the tread run length was varied between 8 and 14 inches (203 mm and 356 mm) in one-inch (25 mm) increments. Kinematic data provided measures of segmental and whole-body dynamic control. Results demonstrated that older adults had greater lateral tilt of the upper body than young adults, but actually had larger margins of stability than the young in the antero-posterior direction as a result of their slower cadence. Nonetheless, for both age groups, the longer run lengths were found to provide the largest margins of stability. In addition, increase in run length and decrease in riser height tended to reduce forward upper body tilt. These results help to explain the underlying biomechanical factors associated with increased risk of falls and the relationship with step geometry. Considering the importance of stair ambulation in maintaining independence and activity in the community, this study highlights the definite need for safer stair design standards to minimize the risk of falls and increase stair safety across the lifespan. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Quantification of temperature persistence over the Northern Hemisphere land-area

NASA Astrophysics Data System (ADS)

Pfleiderer, Peter; Coumou, Dim

2017-10-01

Extreme weather events such as heat waves and floods are damaging to society and their contribution to future climate impacts is expected to be large. Such extremes are often related to persistent local weather conditions. Weather persistence is linked to sea surface temperatures, soil-moisture (especially in summer) and large-scale circulation patterns and these factors can alter under past and future climate change. Though persistence is a key characteristic for extreme weather events, to date the climatology and potential changes in persistence have only been poorly documented. Here, we present a systematic analysis of temperature persistence for the northern hemisphere land area. We define persistence as the length of consecutive warm or cold days and use spatial clustering techniques to create regional persistence distributions. We find that persistence is longest in the Arctic and shortest in the mid-latitudes. Parameterizations of the regional persistence distributions show that they are characterized by an exponential decay with a drop in the decay rate for very persistent events, implying that feedback mechanisms are important in prolonging these events. For the mid-latitudes, we find that persistence in summer has increased over the past 60 years. The changes are particularly pronounced for prolonged events suggesting a lengthening in the duration of heat waves.

Cross-correlations between crude oil and agricultural commodity markets

NASA Astrophysics Data System (ADS)

Liu, Li

2014-02-01

In this paper, we investigate cross-correlations between crude oil and agricultural commodity markets. Based on a popular statistical test proposed by Podobnik et al. (2009), we find that the linear return cross-correlations are significant at larger lag lengths and the volatility cross-correlations are highly significant at all of the lag lengths under consideration. Using a detrended cross-correlation analysis (DCCA), we find that the return cross-correlations are persistent for corn and soybean and anti-persistent for oat and soybean. The volatility cross-correlations are strongly persistent. Using a nonlinear cross-correlation measure, our results show that cross-correlations are relatively weak but they are significant for smaller time scales. For larger time scales, the cross-correlations are not significant. The reason may be that information transmission from crude oil market to agriculture markets can complete within a certain period of time. Finally, based on multifractal extension of DCCA, we find that the cross-correlations are multifractal and high oil prices partly contribute to food crisis during the period of 2006-mid-2008.

Impact of socioeconomic factors on in-patient length of stay and their consequences in per case hospital payment systems.

PubMed

Perelman, Julian; Closon, Marie-Christine

2011-10-01

The number of countries adopting per case hospital payment systems has been continuously increasing in recent years. Nonetheless, debates persist regarding their consequences for equity of access to services. This concern relates to the failure of diagnostic classifications properly to take into account patients' care requirements, raising the threat of case selection ('cream skimming'). We examine the heterogeneity of costs within diagnostic categories related to socioeconomic (SE) factors using length of stay (LOS) as a proxy measure of care needs and costs. We evaluate its consequences in terms of fairness in resource allocation between hospitals. We employ data on all discharges in 2002-03 from a sample of 60 Belgian hospitals (617,275 observations), measuring the association between LOS and SE factors using generalized linear models. We design a resource allocation formula based on the Belgian financing scheme, where non-medical activity is paid based on a normative number of in-patient days, and measure financial penalties and rewards according to whether payment is adjusted for the SE characteristics of patients or not. Both patients' SE status and hospitals' area SE profile have a significant impact on LOS, which persists after controlling for detailed diagnostic and hospital characteristics. Hospitals treating low income patients are financially penalized as a result. SE factors are a predictor of in-patient LOS and should be taken into account in per case resource allocation among hospitals.

Systematic Occlusion of Shunts: Control of Early Postoperative IOP and Hypotony-related Complications Following Glaucoma Shunt Surgery.

PubMed

Sharkawi, Eamon; Artes, Paul H; Oleszczuk, Justyna D; Bela, Cyrielle; Achache, Farid; Barton, Keith; Bergin, Ciara

2016-01-01

Evaluation of a protocol of total intraluminal occlusion of Baerveldt shunts and its effects on early postoperative intraocular pressure (IOP) control and hypotony-related complications. This was a noncomparative, prospective, and interventional study. Glaucoma patients were recruited to undergo Baerveldt shunt surgery. A total of 116 eyes of 112 patients were enrolled. During shunt implantation, aqueous outflow was restricted using an intraluminal occluding stent inserted through the entire tube length, with and without external ligation, to halt aqueous flow. Postoperatively, eyes underwent ligature laser suture lysis and partial or complete stent removals, at predetermined time intervals. Loss of postoperative IOP control was categorized as transient or persistent hypotony (IOP≤5 mm Hg) or hypertony (IOP>21 mm Hg). Patients were followed up for 1 year. Preoperatively median IOP was 23 mm Hg (mean 26 mm Hg, SD 12 mm Hg), median number of glaucoma medications was 3.0 (mean 3.0, SD 1.2). During year 1, laser suture lysis was performed in 30 eyes (26%) and stent removal in 93 eyes (80%) (23 partial; 70 complete). There was 1 case of transient hypotony, no cases of persistent hypotony, 10 of transient hypertony, and 3 of persistent hypertony. Nine eyes had IOP≤5 mm Hg at ≥1 time points and hypotony-related complications occurred in 8 eyes (7%). At 1 year, median IOP was 12 mm Hg (mean 13 mm Hg, SD 4 mm Hg) with a median of 1.0 glaucoma medications (mean 1.1, SD 1.3). The cumulative probability of failure during the first 12 months follow-up was 6% (n=7). Overall postoperative complications occurred in 11 eyes (9%). The surgical and postoperative protocol resulted in controlled, step-wise reductions of IOP with low rates of hypotony and related complications.

Ballistic phonon transport in holey silicon.

PubMed

Lee, Jaeho; Lim, Jongwoo; Yang, Peidong

2015-05-13

When the size of semiconductors is smaller than the phonon mean free path, phonons can carry heat with no internal scattering. Ballistic phonon transport has received attention for both theoretical and practical aspects because Fourier's law of heat conduction breaks down and the heat dissipation in nanoscale transistors becomes unpredictable in the ballistic regime. While recent experiments demonstrate room-temperature evidence of ballistic phonon transport in various nanomaterials, the thermal conductivity data for silicon in the length scale of 10-100 nm is still not available due to experimental challenges. Here we show ballistic phonon transport prevails in the cross-plane direction of holey silicon from 35 to 200 nm. The thermal conductivity scales linearly with the length (thickness) even though the lateral dimension (neck) is as narrow as 20 nm. We assess the impact of long-wavelength phonons and predict a transition from ballistic to diffusive regime using scaling models. Our results support strong persistence of long-wavelength phonons in nanostructures and are useful for controlling phonon transport for thermoelectrics and potential phononic applications.

Structural diversity in binary superlattices self-assembled from polymer-grafted nanocrystals

DOE PAGES

Ye, Xingchen; Zhu, Chenhui; Ercius, Peter; ...

2015-12-02

Multicomponent nanocrystal superlattices represent an interesting class of material that derives emergent properties from mesoscale structure, yet their programmability can be limited by the alkyl-chain-based ligands decorating the surfaces of the constituent nanocrystals. Polymeric ligands offer distinct advantages, as they allow for more precise tuning of the effective size and ‘interaction softness’ through changes to the polymer’s molecular weight, chemical nature, architecture, persistence length and surrounding solvent. Here we show the formation of 10 different binary nanocrystal superlattices (BNSLs) with both two- and three-dimensional order through independent adjustment of the core size of spherical nanocrystals and the molecular weight ofmore » densely grafted polystyrene ligands. These polymer-brush-based ligands introduce new energetic contributions to the interparticle potential that stabilizes various BNSL phases across a range of length scales and interparticle spacings. In conclusion, our study opens the door for nanocrystals to become modular elements in the design of functional particle brush solids with controlled nanoscale interfaces and mesostructures.« less

FLP-18 Functions through the G-Protein-Coupled Receptors NPR-1 and NPR-4 to Modulate Reversal Length in Caenorhabditis elegans.

PubMed

Bhardwaj, Ashwani; Thapliyal, Saurabh; Dahiya, Yogesh; Babu, Kavita

2018-05-16

Animal behavior is critically dependent on the activity of neuropeptides. Reversals, one of the most conspicuous behaviors in Caenorhabditis elegans , plays an important role in determining the navigation strategy of the animal. Our experiments on hermaphrodite C. elegans show the involvement of a neuropeptide FLP-18 in modulating reversal length in these hermaphrodites. We show that FLP-18 controls the reversal length by regulating the activity of AVA interneurons through the G-protein-coupled neuropeptide receptors, NPR-4 and NPR-1. We go on to show that the site of action of these receptors is the AVA interneuron for NPR-4 and the ASE sensory neurons for NPR-1. We further show that mutants in the neuropeptide, flp-18 , and its receptors show increased reversal lengths. Consistent with the behavioral data, calcium levels in the AVA neuron of freely reversing C. elegans were significantly higher and persisted for longer durations in flp-18 , npr-1 , npr-4 , and npr-1 npr-4 genetic backgrounds compared with wild-type control animals. Finally, we show that increasing FLP-18 levels through genetic and physiological manipulations causes shorter reversal lengths. Together, our analysis suggests that the FLP-18/NPR-1/NPR-4 signaling is a pivotal point in the regulation of reversal length under varied genetic and environmental conditions. SIGNIFICANCE STATEMENT In this study, we elucidate the circuit and molecular machinery required for normal reversal behavior in hermaphrodite Caenorhabditis elegans We delineate the circuit and the neuropeptide receptors required for maintaining reversal length in C. elegans Our work sheds light on the importance of a single neuropeptide, FLP-18, and how change in levels in this one peptide could allow the animal to change the length of its reversal, thereby modulating how the C. elegans explores its environment. We also go on to show that FLP-18 functions to maintain reversal length through the neuropeptide receptors NPR-4 and NPR-1. Our study will allow for a better understanding of the complete repertoire of behaviors shown by freely moving animals as they explore their environment. Copyright © 2018 the authors 0270-6474/18/384641-14$15.00/0.

Genetic Variants Related to Longer Telomere Length are Associated with Increased Risk of Renal Cell Carcinoma.

PubMed

Machiela, Mitchell J; Hofmann, Jonathan N; Carreras-Torres, Robert; Brown, Kevin M; Johansson, Mattias; Wang, Zhaoming; Foll, Matthieu; Li, Peng; Rothman, Nathaniel; Savage, Sharon A; Gaborieau, Valerie; McKay, James D; Ye, Yuanqing; Henrion, Marc; Bruinsma, Fiona; Jordan, Susan; Severi, Gianluca; Hveem, Kristian; Vatten, Lars J; Fletcher, Tony; Koppova, Kvetoslava; Larsson, Susanna C; Wolk, Alicja; Banks, Rosamonde E; Selby, Peter J; Easton, Douglas F; Pharoah, Paul; Andreotti, Gabriella; Freeman, Laura E Beane; Koutros, Stella; Albanes, Demetrius; Mannisto, Satu; Weinstein, Stephanie; Clark, Peter E; Edwards, Todd E; Lipworth, Loren; Gapstur, Susan M; Stevens, Victoria L; Carol, Hallie; Freedman, Matthew L; Pomerantz, Mark M; Cho, Eunyoung; Kraft, Peter; Preston, Mark A; Wilson, Kathryn M; Gaziano, J Michael; Sesso, Howard S; Black, Amanda; Freedman, Neal D; Huang, Wen-Yi; Anema, John G; Kahnoski, Richard J; Lane, Brian R; Noyes, Sabrina L; Petillo, David; Colli, Leandro M; Sampson, Joshua N; Besse, Celine; Blanche, Helene; Boland, Anne; Burdette, Laurie; Prokhortchouk, Egor; Skryabin, Konstantin G; Yeager, Meredith; Mijuskovic, Mirjana; Ognjanovic, Miodrag; Foretova, Lenka; Holcatova, Ivana; Janout, Vladimir; Mates, Dana; Mukeriya, Anush; Rascu, Stefan; Zaridze, David; Bencko, Vladimir; Cybulski, Cezary; Fabianova, Eleonora; Jinga, Viorel; Lissowska, Jolanta; Lubinski, Jan; Navratilova, Marie; Rudnai, Peter; Szeszenia-Dabrowska, Neonila; Benhamou, Simone; Cancel-Tassin, Geraldine; Cussenot, Olivier; Bueno-de-Mesquita, H Bas; Canzian, Federico; Duell, Eric J; Ljungberg, Börje; Sitaram, Raviprakash T; Peters, Ulrike; White, Emily; Anderson, Garnet L; Johnson, Lisa; Luo, Juhua; Buring, Julie; Lee, I-Min; Chow, Wong-Ho; Moore, Lee E; Wood, Christopher; Eisen, Timothy; Larkin, James; Choueiri, Toni K; Lathrop, G Mark; Teh, Bin Tean; Deleuze, Jean-Francois; Wu, Xifeng; Houlston, Richard S; Brennan, Paul; Chanock, Stephen J; Scelo, Ghislaine; Purdue, Mark P

2017-11-01

Relative telomere length in peripheral blood leukocytes has been evaluated as a potential biomarker for renal cell carcinoma (RCC) risk in several studies, with conflicting findings. We performed an analysis of genetic variants associated with leukocyte telomere length to assess the relationship between telomere length and RCC risk using Mendelian randomization, an approach unaffected by biases from temporal variability and reverse causation that might have affected earlier investigations. Genotypes from nine telomere length-associated variants for 10 784 cases and 20 406 cancer-free controls from six genome-wide association studies (GWAS) of RCC were aggregated into a weighted genetic risk score (GRS) predictive of leukocyte telomere length. Odds ratios (ORs) relating the GRS and RCC risk were computed in individual GWAS datasets and combined by meta-analysis. Longer genetically inferred telomere length was associated with an increased risk of RCC (OR=2.07 per predicted kilobase increase, 95% confidence interval [CI]:=1.70-2.53, p<0.0001). As a sensitivity analysis, we excluded two telomere length variants in linkage disequilibrium (R 2 >0.5) with GWAS-identified RCC risk variants (rs10936599 and rs9420907) from the telomere length GRS; despite this exclusion, a statistically significant association between the GRS and RCC risk persisted (OR=1.73, 95% CI=1.36-2.21, p<0.0001). Exploratory analyses for individual histologic subtypes suggested comparable associations with the telomere length GRS for clear cell (N=5573, OR=1.93, 95% CI=1.50-2.49, p<0.0001), papillary (N=573, OR=1.96, 95% CI=1.01-3.81, p=0.046), and chromophobe RCC (N=203, OR=2.37, 95% CI=0.78-7.17, p=0.13). Our investigation adds to the growing body of evidence indicating some aspect of longer telomere length is important for RCC risk. Telomeres are segments of DNA at chromosome ends that maintain chromosomal stability. Our study investigated the relationship between genetic variants associated with telomere length and renal cell carcinoma risk. We found evidence suggesting individuals with inherited predisposition to longer telomere length are at increased risk of developing renal cell carcinoma. Published by Elsevier B.V.

Tadpole-like Conformations of Huntingtin Exon 1 Are Characterized by Conformational Heterogeneity that Persists regardless of Polyglutamine Length.

PubMed

Newcombe, Estella A; Ruff, Kiersten M; Sethi, Ashish; Ormsby, Angelique R; Ramdzan, Yasmin M; Fox, Archa; Purcell, Anthony W; Gooley, Paul R; Pappu, Rohit V; Hatters, Danny M

2018-05-11

Soluble huntingtin exon 1 (Httex1) with expanded polyglutamine (polyQ) engenders neurotoxicity in Huntington's disease. To uncover the physical basis of this toxicity, we performed structural studies of soluble Httex1 for wild-type and mutant polyQ lengths. Nuclear magnetic resonance experiments show evidence for conformational rigidity across the polyQ region. In contrast, hydrogen-deuterium exchange shows absence of backbone amide protection, suggesting negligible persistence of hydrogen bonds. The seemingly conflicting results are explained by all-atom simulations, which show that Httex1 adopts tadpole-like structures with a globular head encompassing the N-terminal amphipathic and polyQ regions and the tail encompassing the C-terminal proline-rich region. The surface area of the globular domain increases monotonically with polyQ length. This stimulates sharp increases in gain-of-function interactions in cells for expanded polyQ, and one of these interactions is with the stress-granule protein Fus. Our results highlight plausible connections between Httex1 structure and routes to neurotoxicity. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Brownian trail rectified

NASA Astrophysics Data System (ADS)

Hurd, Alan J.; Ho, Pauline

The experiments described here indicate when one of Nature's best fractals -- the Brownian trail -- becomes nonfractal. In most ambient fluids, the trail of a Brownian particle is self-similar over many decades of length. For example, the trail of a submicron particle suspended in an ordinary liquid, recorded at equal time intervals, exhibits apparently discontinuous changes in velocity from macroscopic lengths down to molecular lengths: the trail is a random walk with no velocity memory from one step to the next. In ideal Brownian motion, the kinks in the trail persist to infinitesimal time intervals, i.e., it is a curve without tangents. Even in real Brownian motion in a liquid, the time interval must be shortened to approximately 10(-8) s before the velocity appears continuous. In sufficiently rarefied environments, this time resolution at which a Brownian trail is rectified from a curve without tangents to a smoothly varying trajectory is greatly lengthened, making it possible to study the kinetic regime by dynamic light scattering. Our recent experiments with particles in a plasma have demonstrated this capability. In this regime, the particle velocity persists over a finite step length allowing an analogy to an ideal gas with Maxwell-Boltzmann velocities; the particle mass could be obtained from equipartition. The crossover from ballistic flight to hydrodynamic diffusion was also seen.

Paired assessment of liver telomere lengths in hepatocellular cancer is a reliable predictor of disease persistence.

PubMed

Feng, Wendu; Yu, Decai; Li, Binghua; Luo, Ou-Yang; Xu, Tiancheng; Cao, Yajuan; Ding, Yitao

2017-04-30

In the present study, we used a small series of highly defined patients, where we had matched timed peripheral blood samples (PBS), as well as paired liver biopsies obtained during collection of blood samples from patients with diagnosed hepatocellular carcinoma (HCC) and compared the correlation between the changes of telomere lengths in these defined samples. Patients included had either HCC alone or in conjunction with either pre-existing hepatitis B virus (HBV) or hepatitis C virus (HCV) infection. PCR-based assay incorporating primers to the telomeric hexamer repeats to polymerize and detect telomeric DNA was used. The average telomere length for each independent assessment was measured by seeing the differences in the intensity of the sample's telomere signal (T) to the signal from a single-copy gene (S-, β-globin) to estimate the standard ratio. Our results provide the first convincing evidence that PBS may be utilized to assay telomere shortening as a predictor for disease persistence in HCC resulting after HBV or HCV infection, but not in non-infectious cause-stimulated HCC. These findings provide incipient opportunity to develop telomere length assessment as a biomarker tool for prediction of HCC in patients with HBV or HCV infection, as well as to gauge responses to chemotherapy and other treatment modalities. © 2017 The Author(s).

Spatiotemporal correlation structure of the Earth's surface temperature

NASA Astrophysics Data System (ADS)

Fredriksen, Hege-Beate; Rypdal, Kristoffer; Rypdal, Martin

2015-04-01

We investigate the spatiotemporal temperature variability for several gridded instrumental and climate model data sets. The temporal variability is analysed by estimating the power spectral density and studying the differences between local and global temperatures, land and sea, and among local temperature records at different locations. The spatiotemporal correlation structure is analysed through cross-spectra that allow us to compute frequency-dependent spatial autocorrelation functions (ACFs). Our results are then compared to theoretical spectra and frequency-dependent spatial ACFs derived from a fractional stochastic-diffusive energy balance model (FEBM). From the FEBM we expect both local and global temperatures to have a long-range persistent temporal behaviour, and the spectral exponent (β) is expected to increase by a factor of two when going from local to global scales. Our comparison of the average local spectrum and the global spectrum shows good agreement with this model, although the FEBM has so far only been studied for a pure land planet and a pure ocean planet, respectively, with no seasonal forcing. Hence it cannot capture the substantial variability among the local spectra, in particular between the spectra for land and sea, and for equatorial and non-equatorial temperatures. Both models and observation data show that land temperatures in general have a low persistence, while sea surface temperatures show a higher, and also more variable degree of persistence. Near the equator the spectra deviate from the power-law shape expected from the FEBM. Instead we observe large variability at time scales of a few years due to ENSO, and a flat spectrum at longer time scales, making the spectrum more reminiscent of that of a red noise process. From the frequency-dependent spatial ACFs we observe that the spatial correlation length increases with increasing time scale, which is also consistent with the FEBM. One consequence of this is that longer-lasting structures must also be wider in space. The spatial correlation length is also observed to be longer for land than for sea. The climate model simulations studied are mainly CMIP5 control runs of length 500-1000 yr. On time scales up to several centuries we do not observe that the difference between the local and global spectral exponents vanish. This also follows from the FEBM and shows that the dynamics is spatiotemporal (not just temporal) even on these time scales.

FACTORS ASSOCIATED WITH INDISCRIMINATE FRIENDLINESS IN HIGH-RISK CHILDREN.

PubMed

Love, Leighanne; Minnis, Helen; O'connor, Suzy

2015-01-01

Indiscriminate friendliness (IF) refers to a lack of reticence with strangers and is well-documented in neglected children. This risky behavior is distinct from attachment insecurity, and persists when parenting/caregiving improves. A previous review has suggested that caregiving quality is not associated with IF. This review aimed to explore factors associated with IF and whether quality of caregiving is important. Ten articles were reviewed using the S.H. Downs and N. Black (1998) Checklist for randomized and nonrandomized studies. Overall quality was high. Results showed that IF is present in fostered populations and postinstitutionalized children. Attachment security was not associated with IF. Length of time in institution and inhibitory control were associated with IF. Inhibitory control moderated the association between IF and number of caregivers. Genetic factors predispose children to IF and may impact on persistence. Quality of caregiving was associated with IF. Emotional availability (i.e., the degree to which carer and child are able to respond to each other's emotional signals) predicted IF. Limitations across studies included heterogeneity in IF measurement and unreliable measures of preadoptive care. Parenting may be a useful target for intervention. Future research should focus on developing a standardized measure of IF as well as evaluating a parental intervention. © 2015 Michigan Association for Infant Mental Health.

Exploring the origin of high optical absorption in conjugated polymers.

PubMed

Vezie, Michelle S; Few, Sheridan; Meager, Iain; Pieridou, Galatia; Dörling, Bernhard; Ashraf, Raja Shahid; Goñi, Alejandro R; Bronstein, Hugo; McCulloch, Iain; Hayes, Sophia C; Campoy-Quiles, Mariano; Nelson, Jenny

2016-07-01

The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

Vulnerability survival analysis: a novel approach to vulnerability management

NASA Astrophysics Data System (ADS)

Farris, Katheryn A.; Sullivan, John; Cybenko, George

2017-05-01

Computer security vulnerabilities span across large, enterprise networks and have to be mitigated by security engineers on a routine basis. Presently, security engineers will assess their "risk posture" through quantifying the number of vulnerabilities with a high Common Vulnerability Severity Score (CVSS). Yet, little to no attention is given to the length of time by which vulnerabilities persist and survive on the network. In this paper, we review a novel approach to quantifying the length of time a vulnerability persists on the network, its time-to-death, and predictors of lower vulnerability survival rates. Our contribution is unique in that we apply the cox proportional hazards regression model to real data from an operational IT environment. This paper provides a mathematical overview of the theory behind survival analysis methods, a description of our vulnerability data, and an interpretation of the results.

On the structure of the turbulent vortex

NASA Technical Reports Server (NTRS)

Roberts, L.

1985-01-01

The trailing vortex generated by a lifting surface, the structure of its turbulent core and the influence of axial flow within the vortex on its initial persistence and on its subsequent decay are described. Similarity solutions of the turbulent diffusion equation are given in closed form and results are expressed in sufficiently simple terms that the influence of the lifting surface parameters on the length of persistence and the rate of decay of the vortex can be evaluated.

Adoptive Cell Therapy for Patients with Melanoma, Using Tumor-Infiltrating Lymphocytes Genetically Engineered to Secrete Interleukin-2

PubMed Central

HEEMSKERK, BIANCA; LIU, KE; DUDLEY, MARK. E.; JOHNSON, LAURA A.; KAISER, ANDREW; DOWNEY, STEPHANIE; ZHENG, ZHILI; SHELTON, THOMAS E.; MATSUDA, KANT; ROBBINS, PAUL F.; MORGAN, RICHARD A.; ROSENBERG, STEVEN A.

2008-01-01

Adoptive cell transfer of tumor-infiltrating lymphocytes (TILs) after lymphodepletion mediates regression in 50% of patients with metastatic melanoma. In vivo persistence and telomere length of the transferred cells correlate with antitumor response. In an attempt to prolong the in vivo survival of the transferred cells, TILs were genetically engineered to produce interleukin (IL)-2. In vitro, these transduced TILs secreted IL-2 while retaining tumor specificity and exhibited prolonged survival after IL-2 withdrawal. In a phase I/II clinical trial, seven evaluable patients received transduced TILs and one patient experienced a partial response associated with in vivo persistence of IL-2-transduced TILs in circulating lymphocytes. An additional five patients received transduced TILs in conjunction with IL-2 administration. Persistence of IL-2-transduced TILs was observed in three patients, including one partial responder. The transgene DNA as well as vector-derived IL-2 mRNA could be detected for 4 months in responding patients. The low response rate in this trial was possibly due to a reduction in telomere length in cells as a result of prolonged in vitro culture. In this study, insertion of the IL-2 gene into antitumor TILs increased their ability to survive after IL-2 withdrawal in vitro but did not increase their in vivo persistence or clinical effectiveness. PMID:18444786

Ablation of Persistent Atrial Fibrillation Targeting Low-Voltage Areas With Selective Activation Characteristics.

PubMed

Jadidi, Amir S; Lehrmann, Heiko; Keyl, Cornelius; Sorrel, Jérémie; Markstein, Viktor; Minners, Jan; Park, Chan-Il; Denis, Arnaud; Jaïs, Pierre; Hocini, Mélèze; Potocnik, Clemens; Allgeier, Juergen; Hochholzer, Willibald; Herrera-Sidloky, Claudia; Kim, Steve; Omri, Youssef El; Neumann, Franz-Josef; Weber, Reinhold; Haïssaguerre, Michel; Arentz, Thomas

2016-03-01

Complex-fractionated atrial electrograms and atrial fibrosis are associated with maintenance of persistent atrial fibrillation (AF). We hypothesized that pulmonary vein isolation (PVI) plus ablation of selective atrial low-voltage sites may be more successful than PVI only. A total of 85 consecutive patients with persistent AF underwent high-density atrial voltage mapping, PVI, and ablation at low-voltage areas (LVA < 0.5 mV in AF) associated with electric activity lasting > 70% of AF cycle length on a single electrode (fractionated activity) or multiple electrodes around the circumferential mapping catheter (rotational activity) or discrete rapid local activity (group I). The procedural end point was AF termination. Arrhythmia freedom was compared with a control group (66 patients) undergoing PVI only (group II). PVI alone was performed in 23 of 85 (27%) patients of group I with low amount (< 10% of left atrial surface area) of atrial low voltage. Selective atrial ablation in addition to PVI was performed in 62 patients with termination of AF in 45 (73%) after 11 ± 9 minutes radiofrequency delivery. AF-termination sites colocalized within LVA in 80% and at border zones in 20%. Single-procedural arrhythmia freedom at 13 months median follow-up was achieved in 59 of 85 (69%) patients in group I, which was significantly higher than the matched control group (31/66 [47%], P < 0.001). There was no significant difference in the success rate of patients in group I with a low amount of low voltage undergoing PVI only and patients requiring PVI+selective low-voltage ablation (P = 0.42). Ablation of sites with distinct activation characteristics within/at borderzones of LVA in addition to PVI is more effective than conventional PVI-only strategy for persistent AF. PVI only seems to be sufficient to treat patients with left atrial low voltage < 10%. © 2016 American Heart Association, Inc.

Stretching, twisting and supercoiling in short, single DNA molecules

NASA Astrophysics Data System (ADS)

Lam, Pui-Man; Zhen, Yi

2018-02-01

We had combined the Neukirch-Marko model that describes the extension, torque and supercoiling in single, stretched and twisted DNA of infinite contour length, with a form of the free energy suggested by Sinha and Samuels to describe short DNA, with contour length only a few times the persistence length. We find that the free energy of the stretched but untwisted DNA, is significantly modified from its infinitely length value and this in turn modifies significantly the torque and supercoiling. We show that this is consistent with short DNA being more flexible than infinitely long DNA. We hope our results will stimulate experimental investigation of torque and supercoiling in short DNA.

The effect of lactation length on greenhouse gas emissions from the national dairy herd.

PubMed

Wall, E; Coffey, M P; Pollott, G E

2012-11-01

Many governments have signed up to greenhouse gas emission (GHGE) reduction programmes under their national climate change obligations. Recently, it has been suggested that the use of extended lactations in dairy herds could result in reduced GHGE. Dairy GHGE were modelled on a national basis and the model was used to compare emissions from lactations of three different lengths (305, 370 and 440 days), and a current 'base' scenario on the basis of maintaining current milk production levels. In addition to comparing GHGE from the average 'National Herd' under these scenarios, results were used to investigate how accounting for lactations of different lengths might alter the estimation of emissions calculated from the National Inventory methodology currently recommended by Intergovernmental Panel on Climate Change. Data for the three lactation length scenarios were derived from nationally recorded dairy performance information and used in the GHGE model. Long lactations required fewer milking cows and replacements to maintain current milk yield levels than short ones, but GHGEs were found to rise from 1214 t of CO2 equivalent (CE)/farm per year for lactations of 305 days to 1371 t CE/farm per year for 440-day lactations. This apparent anomaly can be explained by the less efficient milk production (kg milk produced per kg cow weight) found in later lactation, a more pronounced effect in longer lactations. The sensitivity of the model to changes in replacement rate, persistency and level of milk yield was investigated. Changes in the replacement rate from 25% to 20% and in persistency by −10% to +20% resulted in very small changes in GHGE. Differences in GHGE due to the level of milk yield were much more dramatic with animals in the top 10% for yield, producing about 25% less GHGE/year than the average animal. National Inventory results were investigated using a more realistic spread of lactation lengths than recommended for such calculations using emissions calculated in the first part of the study. Current UK emission calculations based on the National Inventory were 329 Gg of methane per year from the dairy herd. Using the national distribution of lactation lengths, this was found to be an underestimate by about 10%. This work showed that the current rise in lactation length or a move towards calving every 18 months would increase GHGE by 7% to 14% compared with the current scenario, assuming the same milk yield in all models. Increased milk yield would have a much greater effect on reducing GHGE than changes to lactation length, replacement rate or persistency. National Inventory methodology appears to underestimate GHGE when the distribution of lactation lengths is considered and may need revising to provide more realistic figures.

Effects of progressive backward body weight suppoted treadmill training on gait ability in chronic stroke patients: A randomized controlled trial.

PubMed

Kim, Kyung Hun; Lee, Kyoung Bo; Bae, Young-Hyeon; Fong, Shirley S M; Lee, Suk Min

2017-10-23

A stroke patient with hemiplegic gait is generally described as being slow and asymmetric. Body weight-supported treadmill training and backward gait training are recent additions to therapeutic gait trainings that may help improve gait in stroke patient with hemiplegic gait. Therefore, we examined the effect of progressive backward body weight-supported treadmill training on gait in chronic stroke patients with hemiplegic gait. Thirty subjects were divided to the experimental and control groups. The experimental group consisted of 15 patients and underwent progressive backward body weight-supported treadmill training. The control group consisted of 15 patients and underwent general treadmill gait training five times per week, for a total of four weeks. The OptoGait was used to analyze gait kinematics, and the dynamic gait index (DGI) and results of the 6-minute walk test were used as the clinical evaluation indicators. A follow-up test was carried out four weeks later to examine persistence of exercise effects. The experimental group showed statistically significant results in all dependent variables week four compared to the control group. However, until the eighth week, only the dependent variables, of affected step length (ASL), stride length (SL), and DGI differed significantly between the two groups. This study verified that progressive bodyweight-supported treadmill training had a positive influence on the temporospatial characteristics of gait and clinical gait evaluation index in chronic stroke patients.

Inner shelf morphologic controls on the dynamics of the beach and bar system, Fire Island, New York

USGS Publications Warehouse

Hapke, Cheryl J.; Schwab, William C.; Gayes, Paul T.; McCoy, Clay; Viso, Richard; Lentz, Erika E.; Rosati, Julie D.; Wang, Ping; Roberts, Tiffany M.

2011-01-01

The mechanism of sediment exchange between offshore sand ridges and the beach at Fire Island, New York is largely unknown. However, recent evidence from repeat nearshore bathymetry surveys, coupled with the complex but consistent bar morphology and patterns of shoreline change demonstrate that there is a feedback occurring between the regional geologic framework and modern processes. Analysis of bathymetric survey data provides direct confirmation that the offshore ridges are connected to the shoreface and are spatially persistent. The fixed nature of the nearshore morphology is further supported by time series camera data that indicate persistent bars with breaks that re-form in the same locations. A long-term time series of shoreline change shows distinct zones of erosion and accretion that are pervasive over time scales greater than a half-century, and their length-scales are similar to the spacing of the offshore ridge-trough system. The first-order geologic framework is responsible for the existence and locations of the ridges and troughs, which then influence the morphodynamics of the beach and bar system.

Customization of biliopancreatic limb length to modulate and sustain antidiabetic effect of gastric bypass surgery.

PubMed

Pal, A; Rhoads, D B; Tavakkoli, A

2018-02-01

Although Roux-en-Y Gastric Bypass (RYGB) remains the most effective treatment for obesity and type 2 diabetes (T2D), many patients fail to achieve remission, or relapse. Increasing intestinal limb lengths of RYGB may improve outcomes, but the mechanistic basis for this remains unclear. We hypothesize biliopancreatic (BP) limb length modulates the antidiabetic effect of RYGB. Rats underwent RYGB with a 20-cm (RYGB-20cm) or 40-cm (RYGB-40cm) BP limb and were compared with control animals. After 2 and 4 wk, portal and systemic blood was sampled during intestinal glucose infusion. Portosystemic gradient was used to calculate intestinal glucose utilization (G util ), absorption (G absorp ), and hormone secretion. Intestinal morphology and gene expression were assessed. At 2 wk, G absorp progressively decreased with increasing BP limb length; this pattern persisted at 4 wk. G util increased ≈70% in both RYGB-20cm and -40cm groups at 2 wk. At 4 wk, G util progressively increased with limb length. Furthermore, Roux limb weight, and expression of hexokinase and preproglucagon, exhibited a similar progressive increase. At 4 wk, glucagon-like peptide-1 and -2 levels were higher after RYGB-40cm, with associated increased secretion. We conclude that BP limb length modulates multiple antidiabetic mechanisms, analogous to the dose-response relationship of a drug. Early postoperatively, a longer BP limb reduces G absorp . Later, G util , Roux limb hypertrophy, hormone secretion, and hormone levels are increased with longer BP limb. Sustained high incretin levels may prevent weight regain and T2D relapse. These data provide the basis for customizing BP limb length according to patient characteristics and desired metabolic effect. NEW & NOTEWORTHY Biliopancreatic limb length in gastric bypass modulates multiple antidiabetic mechanisms, analogous to the dose-response relationship of a drug. With a longer biliopancreatic limb, Roux limb hypertrophy, increased glucose utilization, reduced glucose absorption, and sustained high incretin levels may prevent weight regain and diabetes relapse.

Energy Savings Lifetimes and Persistence

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

Hoffman, Ian M.; Schiller, Steven R.; Todd, Annika

2016-02-01

This technical brief explains the concepts of energy savings lifetimes and savings persistence and discusses how program administrators use these factors to calculate savings for efficiency measures, programs and portfolios. Savings lifetime is the length of time that one or more energy efficiency measures or activities save energy, and savings persistence is the change in savings throughout the functional life of a given efficiency measure or activity. Savings lifetimes are essential for assessing the lifecycle benefits and cost effectiveness of efficiency activities and for forecasting loads in resource planning. The brief also provides estimates of savings lifetimes derived from amore » national collection of costs and savings for electric efficiency programs and portfolios.« less

End-to-end distance and contour length distribution functions of DNA helices

NASA Astrophysics Data System (ADS)

Zoli, Marco

2018-06-01

I present a computational method to evaluate the end-to-end and the contour length distribution functions of short DNA molecules described by a mesoscopic Hamiltonian. The method generates a large statistical ensemble of possible configurations for each dimer in the sequence, selects the global equilibrium twist conformation for the molecule, and determines the average base pair distances along the molecule backbone. Integrating over the base pair radial and angular fluctuations, I derive the room temperature distribution functions as a function of the sequence length. The obtained values for the most probable end-to-end distance and contour length distance, providing a measure of the global molecule size, are used to examine the DNA flexibility at short length scales. It is found that, also in molecules with less than ˜60 base pairs, coiled configurations maintain a large statistical weight and, consistently, the persistence lengths may be much smaller than in kilo-base DNA.

DNA Motion Capture Reveals the Mechanical Properties of DNA at the Mesoscale

PubMed Central

Price, Allen C.; Pilkiewicz, Kevin R.; Graham, Thomas G.W.; Song, Dan; Eaves, Joel D.; Loparo, Joseph J.

2015-01-01

Single-molecule studies probing the end-to-end extension of long DNAs have established that the mechanical properties of DNA are well described by a wormlike chain force law, a polymer model where persistence length is the only adjustable parameter. We present a DNA motion-capture technique in which DNA molecules are labeled with fluorescent quantum dots at specific sites along the DNA contour and their positions are imaged. Tracking these positions in time allows us to characterize how segments within a long DNA are extended by flow and how fluctuations within the molecule are correlated. Utilizing a linear response theory of small fluctuations, we extract elastic forces for the different, ∼2-μm-long segments along the DNA backbone. We find that the average force-extension behavior of the segments can be well described by a wormlike chain force law with an anomalously small persistence length. PMID:25992731

Structural Evolution of Supercritical CO2 across the Frenkel Line.

PubMed

Bolmatov, Dima; Zav'yalov, D; Gao, M; Zhernenkov, Mikhail

2014-08-21

Here, we study structural properties of the supercritical carbon dioxide and discover the existence of persistent medium-range order correlations, which make supercritical carbon dioxide nonuniform and heterogeneous on an intermediate length scale. We report on the CO2 heterogeneity shell structure where, in the first shell, both carbon and oxygen atoms experience gas-like-type interactions with short-range order correlations while within the second shell, oxygen atoms essentially exhibit a liquid-like type of interactions due to localization of transverse-like phonon packets. Importantly, we highlight a catalytic role of atoms inside of the nearest-neighbor heterogeneity shell in providing a mechanism for diffusion and proving the existence of an additional thermodynamic boundary in the supercritical carbon dioxide on an intermediate length scale. Finally, we discuss important implications for answering the intriguing question whether Venus may have had CO2 oceans and urge for an experimental detection of this persistent local-order heterogeneity.

Persistent and susceptible bacteria with individual deaths.

PubMed

Zucca, Fabio

2014-02-21

The aim of this paper is to study two models for a bacterial population subject to antibiotic treatments. It is known that some bacteria are not sensitive to antibiotics. These bacteria, called persisters, are in a state called persistence and each bacterium can switch from this state to a non-persistent (or susceptible) state and back (with rates b and a respectively). Our models extend those introduced in Garet et al. (2012) by adding a random natural life cycle for each bacterium and by allowing bacteria in the susceptible state to escape the action of the antibiotic with a fixed probability 1-p (while every bacterium in a persistent state survives with probability 1). This last mechanism of survival to the antibiotics differs from the persistent state one (where reproduction is forbidden) since in this case the bacterium can replicate. We study two different models. In the first model we "inject" the antibiotics in the system at fixed, deterministic times while in the second one the time intervals are random. We show that, in order to kill eventually the whole bacterial population, these time intervals cannot be "too large". The maximum admissible length is increasing with respect to p; we see that even when p is close to 1, this interval length can be significantly smaller than in the case p=1. While in the case p=1 switching back and forth to the persistent state is the only chance of surviving for bacteria, when p<1 and the death rate in the persistent state, say dr, is positive then the situation is more complex. In this case our model suggests that if dr and b are positive (and fixed) then for higher values of p there is an interval for the rate a, say (0,ap) where switching to the persistent state is a good strategy while for a>ap the situation is less favorable than a=0. On the other hand, for smaller values of p the best strategy is a=0, that is, not switching. Finally, when dr=0, switching to the susceptible state is always a better strategy, from the bacterial point of view, than staying in the susceptible state all the times. Copyright © 2013 Elsevier Ltd. All rights reserved.

Defect-driven flexochemical coupling in thin ferroelectric films

NASA Astrophysics Data System (ADS)

Eliseev, Eugene A.; Vorotiahin, Ivan S.; Fomichov, Yevhen M.; Glinchuk, Maya D.; Kalinin, Sergei V.; Genenko, Yuri A.; Morozovska, Anna N.

2018-01-01

Using the Landau-Ginzburg-Devonshire theory, we considered the impact of the flexoelectrochemical coupling on the size effects in polar properties and phase transitions of thin ferroelectric films with a layer of elastic defects. We investigated a typical case, when defects fill a thin layer below the top film surface with a constant concentration creating an additional gradient of elastic fields. The defective surface of the film is not covered with an electrode, but instead with an ultrathin layer of ambient screening charges, characterized by a surface screening length. Obtained results revealed an unexpectedly strong effect of the joint action of Vegard stresses and flexoelectric effect (shortly flexochemical coupling) on the ferroelectric transition temperature, distribution of the spontaneous polarization and elastic fields, domain wall structure and period in thin PbTi O3 films containing a layer of elastic defects. A nontrivial result is the persistence of ferroelectricity at film thicknesses below 4 nm, temperatures lower than 350 K, and relatively high surface screening length (˜0.1 nm ) . The origin of this phenomenon is the flexoelectric coupling leading to the rebuilding of the domain structure in the film (namely the cross-over from c-domain stripes to a-type closure domains) when its thickness decreases below 4 nm. The ferroelectricity persistence is facilitated by negative Vegard effect. For positive Vegard effect, thicker films exhibit the appearance of pronounced maxima on the thickness dependence of the transition temperature, whose position and height can be controlled by the defect type and concentration. The revealed features may have important implications for miniaturization of ferroelectric-based devices.

The energetics of tightly bent DNA: a composite elastica model including local melting

NASA Astrophysics Data System (ADS)

Evans, Arthur; Levine, Alex

2012-02-01

Melting transitions are well-known to be affected by the application of mechanical stress. Motivated by the experiments of Zocchi and collaborators (Qu and Zocchi 2011, EPL 94 18003), we explore the effect of the application of mechanical stress on DNA melting in a particular composite of a stiff double stranded piece of DNA (dsDNA), shorter than its own persistence length, whose ends are linked by a flexible single stranded piece of DNA (ssDNA). The flexible ssDNA acts as a Gaussian polymer coil bending the stiff dsDNA through an elastic force that is controllable by the length of the ssDNA chain. In this talk we present theoretical predictions for two experimentally accessible features: the degree of local dsDNA melting and the local elastic energy of the dsDNA/ssDNA construct both as a function of the length of the attached ssDNA. We also address the effect of introducing a nick (broken covalent bond) in the dsDNA backbone on these results and discuss the implications of such data on the relative importance of backbone elasticity versus base stacking and base pairing interactions in determining the elasticity of dsDNA. This work also addresses open questions in the nonlinear elasticity of DNA in tightly bent curves.

AFM-based detection of glycocalyx degradation and endothelial stiffening in the db/db mouse model of diabetes.

PubMed

Targosz-Korecka, Marta; Jaglarz, Magdalena; Malek-Zietek, Katarzyna E; Gregorius, Aleksandra; Zakrzewska, Agnieszka; Sitek, Barbara; Rajfur, Zenon; Chlopicki, Stefan; Szymonski, Marek

2017-11-21

Degradation of the glycocalyx and stiffening of endothelium are important pathophysiological components of endothelial dysfunction. However, to our knowledge, these events have not been investigated in tandem in experimental diabetes. Here, the mechanical properties of the glycocalyx and endothelium in ex vivo mouse aorta were determined simultaneously in indentation experiments with an atomic force microscope (AFM) for diabetic db/db and control db/+ mice at ages of 11-19 weeks. To analyze highly heterogeneous aorta samples, we developed a tailored classification procedure of indentation data based on a bi-layer brush model supplemented with Hertz model for quantification of nanomechanics of endothelial regions with and without the glycocalyx surface. In db/db mice, marked endothelial stiffening and reduced glycocalyx coverage were present already in 11-week-old mice and persisted in older animals. In contrast, reduction of the effective glycocalyx length was progressive and was most pronounced in 19-week-old db/db mice. The reduction of the glycocalyx length correlated with an increasing level of glycated haemoglobin and decreased endothelial NO production. In conclusion, AFM nanoindentation analysis revealed that stiffening of endothelial cells and diminished glycocalyx coverage occurred in early diabetes and were followed by the reduction of the glycocalyx length that correlated with diabetes progression.

Fragmentation of cosmic-string loops

NASA Technical Reports Server (NTRS)

York, Thomas

1989-01-01

The fragmentation of cosmic string loops is discussed, and the results of a simulation of this process are presented. The simulation can evolve any of a large class of loops essentially exactly, including allowing fragments that collide to join together. Such reconnection enhances the production of small fragments, but not drastically. With or without reconnections, the fragmentation process produces a collection of nonself-intersecting loops whose typical length is on the order of the persistence length of the initial loop.

Nanostructure Control of Biologically Inspired Polymers

NASA Astrophysics Data System (ADS)

Rosales, Adrianne Marie

Biological polymers, such as polypeptides, are responsible for many of life's most sophisticated functions due to precisely evolved hierarchical structures. These protein structures are the result of monodisperse sequences of amino acids that fold into well-defined chain shapes and tertiary structures. Recently, there has been much interest in the design of such sequence-specific polymers for materials applications in fields ranging from biotechnology to separations membranes. Non-natural polymers offer the stability and robustness necessary for materials applications; however, our ability to control monomer sequence in non-natural polymers has traditionally operated on a much simpler level. In addition, the relationship between monomer sequence and self-assembly is not well understood for biological molecules, much less synthetic polymers. Thus, there is a need to explore self-assembly phase space with sequence using a model system. Polypeptoids are non-natural, sequence-specific polymers that offer the opportunity to probe the effect of sequence on self-assembly. A variety of monomer interactions have an impact on polymer properties, such as chirality, hydrophobicity, and electrostatic interactions. Thus, a necessary starting point for this project was to investigate monomer sequence effects on the bulk properties of polypeptoid homopolymers. It was found that several polypeptoids have experimentally accessible melting transitions that are dependent on the choice of side chains, and it was shown that this transition is tuned by the incorporation of "defects" or a comonomer. The polypeptoid chain shape is also controlled with the choice of monomer and monomer sequence. By using at least 50% monomers with bulky, chiral side chains, the polypeptoid backbone is sterically twisted into a helix, and as found for the first time in this work, the persistence length is increased. However, this persistence length, which is a measure of the stiffness of the polymer, is small compared to other folded helices, indicating the conformational flexibility of polypeptoid chains. With a firmer understanding of how monomer sequence and composition influence polypeptoid bulk properties, we designed block copolymer systems for self-assembly. Because the governing parameters of block copolymer self-assembly are well understood, this architecture provides a convenient starting point for probing the effect of changing polymer sequence. We found that polystyrene-polypeptoid block copolymers readily self-assemble into hexagonally-packed and lamellar morphologies with long range order, and furthermore, sequence control of the polypeptoid block enables us to tune the strength of segregation (and therefore the order-disorder transition) of the block copolymer. Polypeptoid chain shape also affects self-assembly. In classical synthetic block copolymers, it has typically been difficult to change chain shape without also changing polymer chemistry and therefore other factors affecting self-assembly. The advantage of the polypeptoid system is that it is modular, as the side chain chemistry (and therefore polymer properties) can easily be changed without changing the backbone chemistry. Thus, we have decoupled conformational effects from chemical composition by comparing the self-assembly of block copolymers containing either a helical peptoid block or its racemic, non-helical analog. The increase in the persistence length of the peptoid block due to helicity translates to an increase in the morphological domain spacing. In this work, we further the understanding of the effect of monomer sequence on bulk polypeptoid properties and self-assembly. Our findings pave the way for the rational design of structured synthetic polymers with tunable, sequence-specific properties.

Persistent organochlorine pollutants and menstrual cycle characteristics

PubMed Central

Buck Louis, Germaine M.; Rios, Lisbeth Iglesias; McLain, Alexander; Cooney, Maureen A.; Kostyniak, Paul J.; Sundaram, Rajeshwari

2014-01-01

An evolving body of evidence suggests an adverse relation between persistent organochlorine pollutants (POPs) and menstruation, though prospective longitudinal measurement of menses is limited and served as the impetus for study. We prospectively assessed the relation between a mixture of persistent organochlorine compounds and menstrual cycle length and duration of bleeding in a cohort of women attempting to become pregnant. Eighty-three (83%) women contributing 447 cycles for analysis provided a blood specimen for the quantification of 76 polychlorinated biphenyls and seven organochlorine pesticides, and completed daily diaries on menstruation until a human chorionic gonadotropin confirmed pregnancy or 12 menstrual cycles without conception. Gas chromatography with electron capture detection was used to quantify concentrations (ng g−1 serum); enzymatic methods were used to quantify serum lipids (mg dL−1). A linear regression model with a mixture distribution was used to identify chemicals grouped by purported biologic activity that significantly affected menstrual cycle length and duration of bleeding adjusting for age at menarche and enrollment, body mass index, and cigarette smoking. A significant 3-d increase in cycle length was observed for women in the highest tertile of estrogenic PCB congeners relative to the lowest tertile (β = 3.20; 95% CI 0.36, 6.04). A significant reduction in bleeding (<1 d) was observed among women in the highest versus lowest tertile of aromatic fungicide exposure (γ = −0.15; 95% CI −0.29, −0.00). Select POPs were associated with changes in menstruation underscoring the importance of assessing chemical mixtures for female fecundity. PMID:22018858

The Incorporation of Ribonucleotides Induces Structural and Conformational Changes in DNA.

PubMed

Meroni, Alice; Mentegari, Elisa; Crespan, Emmanuele; Muzi-Falconi, Marco; Lazzaro, Federico; Podestà, Alessandro

2017-10-03

Ribonucleotide incorporation is the most common error occurring during DNA replication. Cells have hence developed mechanisms to remove ribonucleotides from the genome and restore its integrity. Indeed, the persistence of ribonucleotides into DNA leads to severe consequences, such as genome instability and replication stress. Thus, it becomes important to understand the effects of ribonucleotides incorporation, starting from their impact on DNA structure and conformation. Here we present a systematic study of the effects of ribonucleotide incorporation into DNA molecules. We have developed, to our knowledge, a new method to efficiently synthesize long DNA molecules (hundreds of basepairs) containing ribonucleotides, which is based on a modified protocol for the polymerase chain reaction. By means of atomic force microscopy, we could therefore investigate the changes, upon ribonucleotide incorporation, of the structural and conformational properties of numerous DNA populations at the single-molecule level. Specifically, we characterized the scaling of the contour length with the number of basepairs and the scaling of the end-to-end distance with the curvilinear distance, the bending angle distribution, and the persistence length. Our results revealed that ribonucleotides affect DNA structure and conformation on scales that go well beyond the typical dimension of the single ribonucleotide. In particular, the presence of ribonucleotides induces a systematic shortening of the molecules, together with a decrease of the persistence length. Such structural changes are also likely to occur in vivo, where they could directly affect the downstream DNA transactions, as well as interfere with protein binding and recognition. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Moderate glycemic control safe in critically ill adult burn patients: A 15 year cohort study.

PubMed

Stoecklin, Patricia; Delodder, Frederik; Pantet, Olivier; Berger, Mette M

2016-02-01

Hyperglycemia is a metabolic alteration in major burn patients associated with complications. The study aimed at evaluating the safety of general ICU glucose control protocols applied in major burns receiving prolonged ICU treatment. 15 year retrospective analysis of consecutive, adult burn patients admitted to a single specialized centre. death or length of stay <10 days, age <16 years. demographic variables, burned surface (TBSA), severity scores, infections, ICU stay, outcome. Metabolic variables: total energy, carbohydrate and insulin delivery/24h, arterial blood glucose and CRP values. Analysis of 4 periods: 1, before protocol; 2, tight doctor driven; 3, tight nurse driven; 4, moderate nurse driven. 229 patients, aged 45 ± 20 years (mean ± SD), burned 32 ± 20% TBSA were analyzed. SAPSII was 35 ± 13. TBSA, Ryan and ABSI remained stable. Inhalation injury increased. A total of 28,690 blood glucose samples were analyzed: the median value remained unchanged with a narrower distribution over time. After the protocol initiation, the normoglycemic values increased from 34.7% to 65.9%, with a reduction of hypoglycaemic events (no extreme hypoglycemia in period 4). Severe hyperglycemia persisted throughout with a decrease in period 4 (9.25% in period 4). Energy and glucose deliveries decreased in periods 3 and 4 (p<0.0001). Infectious complications increased during the last 2 periods (p=0.01). A standardized ICU glucose control protocol improved the glycemic control in adult burn patients, reducing glucose variability. Moderate glycemic control in burns was safe specifically related to hypoglycemia, reducing the incidence of hypoglycaemic events compared to the period before. Hyperglycemia persisted at a lower level. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Combination of Heat Shock and Enhanced Thermal Regime to Control the Growth of a Persistent Legionella pneumophila Strain

PubMed Central

Bédard, Emilie; Boppe, Inès; Kouamé, Serge; Martin, Philippe; Pinsonneault, Linda; Valiquette, Louis; Racine, Jules; Prévost, Michèle

2016-01-01

Following nosocomial cases of Legionella pneumophila, the investigation of a hot water system revealed that 81.5% of sampled taps were positive for L. pneumophila, despite the presence of protective levels of copper in the water. A significant reduction of L. pneumophila counts was observed by culture after heat shock disinfection. The following corrective measures were implemented to control L. pneumophila: increasing the hot water temperature (55 to 60 °C), flushing taps weekly with hot water, removing excess lengths of piping and maintaining a water temperature of 55 °C throughout the system. A gradual reduction in L. pneumophila counts was observed using the culture method and qPCR in the 18 months after implementation of the corrective measures. However, low level contamination was retained in areas with hydraulic deficiencies, highlighting the importance of maintaining a good thermal regime at all points within the system to control the population of L. pneumophila. PMID:27092528

Role of initial correlation in coarsening of a ferromagnet

NASA Astrophysics Data System (ADS)

Chakraborty, Saikat; Das, Subir K.

2015-06-01

We study the dynamics of ordering in ferromagnets via Monte Carlo simulations of the Ising model, employing the Glauber spin-flip mechanism, in space dimensions d = 2 and 3, on square and simple cubic lattices. Results for the persistence probability and the domain growth are discussed for quenches to various temperatures (Tf) below the critical one (Tc), from different initial temperatures Ti ≥ Tc. In long time limit, for Ti>Tc, the persistence probability exhibits power-law decay with exponents θ ≃ 0.22 and ≃ 0.18 in d = 2 and 3, respectively. For finite Ti, the early time behavior is a different power-law whose life-time diverges and exponent decreases as Ti → Tc. The two steps are connected via power-law as a function of domain length and the crossover to the second step occurs when this characteristic length exceeds the equilibrium correlation length at T = Ti. Ti = Tc is expected to provide a new universality class for which we obtain θ ≡ θc ≃ 0.035 in d = 2 and ≃0.105 in d = 3. The time dependence of the average domain size ℓ, however, is observed to be rather insensitive to the choice of Ti.

Correlation between sexual maturation and induction of persistent estrus by continuous illumination.

PubMed

Takeo, Y; Shirama, K; Shimizu, K; Maekawa, K

1975-10-01

The rats brought up under continuous illumination from the neonatal day persist in the rhythmic estrous cycle for long time and do not easily reveal so-called continuous vaginal estrus. On the contrary, immature rats at about 30 days of age show the persistent estrus soon after exposure to continuous illumination as well as adult rats. The purpose of this paper was to examine the relation of the age placed under continuous illumination and the time required to reach the persistent estrus. As the results, it was found that the younger rats need proportionally the longer time to reach the persistent estrus; the rats which were transferred into continuously illuminated environment at 0 (group A), 5 (group B), 10 (group C), 15-16 (group D) and 30 (group E) days of age required a mean time of 132.1 +/- 8.4, 126.8 +/- 8.9, 89.7 +/- 6.2, 91.5 +/- 3.8 and 70.3 +/- 3.0 days after birth to reach the persistent estrus, respectively. In the present data, a significant difference was seen between group B and C. Though all rats were killed after the same length of persistently estrous periods, actual endocrine level appeared to differ among the groups; the rats required longer time to reach the persistent estrus had smaller ovaries and adrenals.

Walking Speed Influences the Effects of Implicit Visual Feedback Distortion on Modulation of Gait Symmetry

PubMed Central

Maestas, Gabrielle; Hu, Jiyao; Trevino, Jessica; Chunduru, Pranathi; Kim, Seung-Jae; Lee, Hyunglae

2018-01-01

The use of visual feedback in gait rehabilitation has been suggested to promote recovery of locomotor function by incorporating interactive visual components. Our prior work demonstrated that visual feedback distortion of changes in step length symmetry entails an implicit or unconscious adaptive process in the subjects’ spatial gait patterns. We investigated whether the effect of the implicit visual feedback distortion would persist at three different walking speeds (slow, self-preferred and fast speeds) and how different walking speeds would affect the amount of adaption. In the visual feedback distortion paradigm, visual vertical bars portraying subjects’ step lengths were distorted so that subjects perceived their step lengths to be asymmetric during testing. Measuring the adjustments in step length during the experiment showed that healthy subjects made spontaneous modulations away from actual symmetry in response to the implicit visual distortion, no matter the walking speed. In all walking scenarios, the effects of implicit distortion became more significant at higher distortion levels. In addition, the amount of adaptation induced by the visual distortion was significantly greater during walking at preferred or slow speed than at the fast speed. These findings indicate that although a link exists between supraspinal function through visual system and human locomotion, sensory feedback control for locomotion is speed-dependent. Ultimately, our results support the concept that implicit visual feedback can act as a dominant form of feedback in gait modulation, regardless of speed. PMID:29632481

Photoperiod control of downstream movements of Atlantic salmon Salmo salar smolts

USGS Publications Warehouse

Zydlewski, Gayle B.; Stich, Daniel S.; McCormick, Stephen D.

2014-01-01

This study provides the first direct observations that photoperiod controls the initiation of downstream movement in Atlantic salmon Salmo salar smolts. Under simulated natural day length (LDN) conditions and seasonal increases in temperature, smolts increased their downstream movements five-fold for a period of 1 month in late spring. Under the same conditions, parr did not show changes in downstream movement behaviour. When given a shortened day length (10L:14D) beginning in late winter, smolts did not increase the number of downstream movements. An early increase in day length (16L:8D) in late winter resulted in earlier initiation and termination of downstream movements compared to the LDN group. Physiological status and behaviour were related but not completely coincident: gill Na+/K+-ATPase activity increased in all treatments and thyroid hormone was elevated prior to movement in 16L:8D treatment. The most parsimonious model describing downstream movement of smolts included synergistic effects of photoperiod treatment and temperature, indicating that peak movements occurred at colder temperatures in the 16L:8D treatment than in LDN, and temperature did not influence movement of smolts in the 10L:14D treatment. The complicated interactions of photoperiod and temperature are not surprising since many organisms have evolved to rely on correlations among environmental cues and windows of opportunity to time behaviours associated with life-history transitions. These complicated interactions, however, have serious implications for phenological adjustments and persistence ofS. salar populations in response to climate change.

Dentate gyrus volume is reduced before onset of plaque formation in PDAPP mice: A magnetic resonance microscopy and stereologic analysis

PubMed Central

Redwine, Jeffrey M.; Kosofsky, Barry; Jacobs, Russell E.; Games, Dora; Reilly, John F.; Morrison, John H.; Young, Warren G.; Bloom, Floyd E.

2003-01-01

High-resolution magnetic resonance microscopy (MRM) was used to determine regional brain volumetric changes in a mouse model of Alzheimer's disease. These transgenic (Tg) mice overexpress human mutant amyloid precursor protein (APP) V717F under control of platelet-derived growth factor promoter (PDAPP mice), and cortical and hippocampal β-amyloid (Aβ) deposits accumulate in heterozygotes after 8–10 mos. We used MRM to obtain 3D volumetric data on mouse brains imaged in their skulls to define genotype- and age-related changes. Hippocampal, cerebellar, and brain volumes and corpus callosum length were quantified in 40-, 100-, 365-, and 630-day-old mice. Measurements taken at age 100 days, before Aβ deposition, revealed a 12.3% reduction of hippocampus volume in Tg mice compared with WT controls. This reduction persisted without progression to age 21 mos. A significant 18% increase in hippocampal volume occurred between 40 and 630 days in WT mice, and no corresponding significant increase occurred in Tg mice. Cavalieri volume estimates of hippocampal subfields from 100-day-old Tg mice further localized a 28% volume deficit in the dentate gyrus. In addition, corpus callosum length was reduced by ≈25% in Tg mice at all ages analyzed. In summary, reduced hippocampal volume and corpus callosum length can be detected by MRM before Aβ deposition. We conclude that overexpression of APP and amyloid may initiate pathologic changes before the appearance of plaques, suggesting novel targets for the treatment of Alzheimer's disease and further reinforcing the need for early diagnosis and treatment. PMID:12552120

Data-Limited Population-Status Evaluation of Two Coastal Fishes in Southern Angola Using Recreational Catch Length-Frequency Data

PubMed Central

Beckensteiner, Jennifer; Kaplan, David M.; Potts, Warren M.; Santos, Carmen V.; O’Farrell, Michael R.

2016-01-01

Excessive truncation of a population’s size structure is often identified as an important deleterious effect of exploitation, yet the effect on population persistence of size-structure truncation caused by exploitation is often not quantified due to data limitations. In this study, we estimate changes in eggs per recruit (EPR) using annual length-frequency samples over a 9 year period to assess persistence of the two most important recreational fishes in southern Angola: west coast dusky kob (Argyrosomus coronus) and leerfish (Lichia amia). Using a length- and age-structured model, we improve on an existing method to fit this type of model to length-frequency data and estimate EPR. The objectives of the methodological changes are to add flexibility and robustness to the approach for assessing population status in data-limited situations. Results indicate that dusky kob presents very low levels of EPR (5%-10% of the per recruit reproductive capacity in the absence of fishing) in 2013, whereas large inter-annual variability in leerfish estimates suggest caution must be applied when drawing conclusions about its exploitation status. Using simulated length frequency data with known parameter values, we demonstrate that recruitment decline due to overexploitation leads to overestimation of EPR values. Considering the low levels of EPR estimated for the study species, recruitment limitation is not impossible and true EPR values may be even lower than our estimates. It is, therefore, likely that management action, such as the creation of Marine Protected Areas, is needed to reconstitute the west coast dusky kob population. PMID:26829489

Data-Limited Population-Status Evaluation of Two Coastal Fishes in Southern Angola Using Recreational Catch Length-Frequency Data.

PubMed

Beckensteiner, Jennifer; Kaplan, David M; Potts, Warren M; Santos, Carmen V; O'Farrell, Michael R

2016-01-01

Excessive truncation of a population's size structure is often identified as an important deleterious effect of exploitation, yet the effect on population persistence of size-structure truncation caused by exploitation is often not quantified due to data limitations. In this study, we estimate changes in eggs per recruit (EPR) using annual length-frequency samples over a 9 year period to assess persistence of the two most important recreational fishes in southern Angola: west coast dusky kob (Argyrosomus coronus) and leerfish (Lichia amia). Using a length- and age-structured model, we improve on an existing method to fit this type of model to length-frequency data and estimate EPR. The objectives of the methodological changes are to add flexibility and robustness to the approach for assessing population status in data-limited situations. Results indicate that dusky kob presents very low levels of EPR (5%-10% of the per recruit reproductive capacity in the absence of fishing) in 2013, whereas large inter-annual variability in leerfish estimates suggest caution must be applied when drawing conclusions about its exploitation status. Using simulated length frequency data with known parameter values, we demonstrate that recruitment decline due to overexploitation leads to overestimation of EPR values. Considering the low levels of EPR estimated for the study species, recruitment limitation is not impossible and true EPR values may be even lower than our estimates. It is, therefore, likely that management action, such as the creation of Marine Protected Areas, is needed to reconstitute the west coast dusky kob population.

Potential population growth and harmful effects on humans from bed bug populations exposed to different feeding regimes.

PubMed

Pereira, R M; Taylor, A S; Lehnert, M P; Koehler, P G

2013-06-01

Effects of host availability and feeding period on bed bugs, Cimex lectularius (L.) (Hemiptera: Cimicidae), were measured. Population growth and the potential harmful effect of bed bug populations on human hosts were modelled. Bloodmeal sizes were affected by both feeding length and frequency, with >2-fold difference between insects fed daily or weekly. Blood consumption increased >2-fold between bed bugs fed occasionally and often, and 1.5-fold between occasional and daily feeding. Bed bugs fed more often than once a week, potentially every 2-4 days. Egg production was associated with nutrition, being strongly correlated with blood consumption in the previous week. Bed bug populations can grow under different feeding regimes and are hard to control with <80% mortality. Bed bugs can survive and grow even in locations with a limited blood supply, where bed bug persistence may be important for the continual spread of populations. Persistence in non-traditional locations and a potential association with human pathogens increase the health risks of bed bugs. Potential blood loss as a result of a bed bug can have serious consequences because uncontrolled populations can reach harmful levels in 3-8 months. The reproduction potential of bed bug populations suggests serious consequences to human health and the need for efficacious control measures. © 2012 The Royal Entomological Society.

The link between discrimination and telomere length in African American adults.

PubMed

Lee, Daniel B; Kim, Eric S; Neblett, Enrique W

2017-05-01

Prior work shows that discrimination is associated with a wide array of negative health outcomes. However, the biological mechanisms through which this link occurs require more study. We evaluated the association between discrimination and leukocyte telomere length (LTL; a biological marker of systemic aging). Cross-sectional data were from the Health and Retirement study, a study of people aged 51+ in the United States, and included 595 African American males and females. Multiple regression analyses were used to evaluate whether discrimination was independently associated with LTL. We also considered the role of potential confounders including sociodemographic factors, health factors, depressive symptoms, and stress. High discrimination was associated with shorter LTL after controlling for sociodemographic factors (b = -.034, SE = 0.14, p = .017). This association persisted in analyses that further adjusted for health factors, depressive symptoms, and stress. Results suggest that discrimination experiences accelerate biological aging in older African American males and females, alike. This finding helps advance our understanding of how discrimination generates greater disease vulnerability and premature death in African Americans. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Volumetric Muscle Loss: Persistent Functional Deficits Beyond Frank Loss of Tissue

DTIC Science & Technology

2014-09-18

ing musculature5,6 that almost certainly changes the muscle’s architecture (e.g., fiber length to muscle length ratio) and composition (e.g...Vivo Isometric Functional Assessment TA muscle in vivo mechanical properties were measured in anesthetized rats (isoflurane 1.5–2.0%) in both legs as...testing system.5 Peak TA muscle isometric torque was determined with the ankle at a right angle 0˚ and 20˚ of dorsi- or plantar flexion, assuming a moment

Persistent current and zero-energy Majorana modes in a p -wave disordered superconducting ring

NASA Astrophysics Data System (ADS)

Nava, Andrea; Giuliano, Rosa; Campagnano, Gabriele; Giuliano, Domenico

2017-04-01

We discuss the emergence of zero-energy Majorana modes in a disordered finite-length p -wave one-dimensional superconducting ring, pierced by a magnetic flux Φ tuned at an appropriate value Φ =Φ* . In the absence of fermion parity conservation, we evidence the emergence of the Majorana modes by looking at the discontinuities in the persistent current I [Φ ] at Φ =Φ* . By monitoring the discontinuities in I [Φ ] , we map out the region in parameter space characterized by the emergence of Majorana modes in the disordered ring.

Persistent Homology to describe Solid and Fluid Structures during Multiphase Flow

NASA Astrophysics Data System (ADS)

Herring, A. L.; Robins, V.; Liu, Z.; Armstrong, R. T.; Sheppard, A.

2017-12-01

The question of how to accurately and effectively characterize essential fluid and solid distributions and structures is a long-standing topic within the field of porous media and fluid transport. For multiphase flow applications, considerable research effort has been made to describe fluid distributions under a range of conditions; including quantification of saturation levels, fluid-fluid pressure differences and interfacial areas, and fluid connectivity. Recent research has effectively used topological metrics to describe pore space and fluid connectivity, with researchers demonstrating links between pore-scale nonwetting phase topology to fluid mobilization and displacement mechanisms, relative permeability, fluid flow regimes, and thermodynamic models of multiphase flow. While topology is clearly a powerful tool to describe fluid distribution, topological metrics by definition provide information only on the connectivity of a phase, not its geometry (shape or size). Physical flow characteristics, e.g. the permeability of a fluid phase within a porous medium, are dependent on the connectivity of the pore space or fluid phase as well as the size of connections. Persistent homology is a technique which provides a direct link between topology and geometry via measurement of topological features and their persistence from the signed Euclidean distance transform of a segmented digital image (Figure 1). We apply persistent homology analysis to measure the occurrence and size of pore-scale topological features in a variety of sandstones, for both the dry state and the nonwetting phase fluid during two-phase fluid flow (drainage and imbibition) experiments, visualized with 3D X-ray microtomography. The results provide key insights into the dominant topological features and length scales of a media which control relevant field-scale engineering properties such as fluid trapping, absolute permeability, and relative permeability.

Self assembled linear polymeric chains with tuneable semiflexibility using isotropic interactions.

PubMed

Abraham, Alex; Chatterji, Apratim

2018-04-21

We propose a two-body spherically symmetric (isotropic) potential such that particles interacting by the potential self-assemble into linear semiflexible polymeric chains without branching. By suitable control of the potential parameters, we can control the persistence length of the polymer and can even introduce a controlled number of branches. Thus we show how to achieve effective directional interactions starting from spherically symmetric potentials. The self-assembled polymers have an exponential distribution of chain lengths akin to what is observed for worm-like micellar systems. On increasing particle density, the polymeric chains self-organize to an ordered line-hexagonal phase where every chain is surrounded by six parallel chains, the transition is first order. On further increase in monomer density, the order is destroyed and we get a branched gel-like phase. This potential can be used to model semi-flexible equilibrium polymers with tunable semiflexibility and excluded volume. The use of the potential is computationally cheap and hence can be used to simulate and probe equilibrium polymer dynamics with long chains. The potential also gives a plausible method of tuning colloidal interactions in experiments such that one can obtain self-assembling polymeric chains made up of colloids and probe polymer dynamics using an optical microscope. Furthermore, we show how a modified potential leads to the observation of an intermediate nematic phase of self-assembled chains in between the low density disordered phase and the line-ordered hexagonal phase.

Self assembled linear polymeric chains with tuneable semiflexibility using isotropic interactions

NASA Astrophysics Data System (ADS)

Abraham, Alex; Chatterji, Apratim

2018-04-01

We propose a two-body spherically symmetric (isotropic) potential such that particles interacting by the potential self-assemble into linear semiflexible polymeric chains without branching. By suitable control of the potential parameters, we can control the persistence length of the polymer and can even introduce a controlled number of branches. Thus we show how to achieve effective directional interactions starting from spherically symmetric potentials. The self-assembled polymers have an exponential distribution of chain lengths akin to what is observed for worm-like micellar systems. On increasing particle density, the polymeric chains self-organize to an ordered line-hexagonal phase where every chain is surrounded by six parallel chains, the transition is first order. On further increase in monomer density, the order is destroyed and we get a branched gel-like phase. This potential can be used to model semi-flexible equilibrium polymers with tunable semiflexibility and excluded volume. The use of the potential is computationally cheap and hence can be used to simulate and probe equilibrium polymer dynamics with long chains. The potential also gives a plausible method of tuning colloidal interactions in experiments such that one can obtain self-assembling polymeric chains made up of colloids and probe polymer dynamics using an optical microscope. Furthermore, we show how a modified potential leads to the observation of an intermediate nematic phase of self-assembled chains in between the low density disordered phase and the line-ordered hexagonal phase.

Control of Uncertain Systems under Constraints: Switching Horizon Predictive Control of Persistently Disturbed Input-Saturated Plants

DTIC Science & Technology

2006-12-01

on at any time from a family of candidate feedback-gains so as to control a discrete- time input-saturated LTI system possibly subject to persistent... times robustness Mosca, E. (2006) Control of Uncertain Systems under Constraints: Switching Horizon Predictive Control of Persistently Disturbed...feedback controls u = f(x̂) (3) so as to ensure, under suitable conditions, stability in the noiseless case as well as finite l∞-induced gain of the

Hypolactasia is associated with insulin resistance in nonalcoholic steatohepatitis

PubMed Central

de Campos Mazo, Daniel Ferraz; Mattar, Rejane; Stefano, José Tadeu; da Silva-Etto, Joyce Matie Kinoshita; Diniz, Márcio Augusto; Duarte, Sebastião Mauro Bezerra; Rabelo, Fabíola; Lima, Rodrigo Vieira Costa; de Campos, Priscila Brizolla; Carrilho, Flair José; Oliveira, Claudia P

2016-01-01

AIM To assess lactase gene (LCT)-13910C>T polymorphisms in Brazilian non-alcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) patients in comparison with healthy controls. METHODS This was a transverse observational clinical study with NAFLD patients who were followed at the Hepatology Outpatient Unit of the Hospital das Clínicas, São Paulo, Brazil. The polymorphism of lactase non-persistence/lactase persistence (LCT-13910C>T) was examined by PCR-restriction fragment length polymorphism technique in 102 liver biopsy-proven NAFLD patients (steatosis in 9 and NASH in 93) and compared to those of 501 unrelated healthy volunteers. Anthropometric, clinical, biochemical and liver histology data were analyzed. Continuous variables were compared using the t or Mann-Whitney tests, and categorical data were compared with the Fisher’s exact test. Univariate logistic regression and multivariate logistic regression adjusted for gender and age were performed. RESULTS No differences in the LCT-13910 genotype frequencies were noted between the NAFLD patients (66.67% of the patients with steatosis were CC, 33.33% were CT, and none were TT; 55.91% of the patients with NASH were CC, 39.78% were CT, and 4.3% were TT; P = 0.941) and the healthy controls (59.12% were CC, 35.67% were CT, and 5.21% were TT) or between the steatosis and NASH patients. That is, the distribution of the lactase non-persistence/lactase persistence polymorphism (LCT-13910C>T) in the patients with NAFLD was equal to that in the general population. In the NASH patients, the univariate analysis revealed that the lactase non-persistence (low lactase activity or hypolactasia) phenotype was associated with higher insulin levels (23.47 ± 15.94 μU/mL vs 15.8 ± 8.33 μU/mL, P = 0.027) and a higher frequency of insulin resistance (91.84% vs 72.22%, P = 0.02) compared with the lactase persistence phenotype. There were no associations between the LCT genotypes and diabetes (P = 0.651), dyslipidaemia (P = 0.328), hypertension (P = 0.507) or liver histology in these patients. Moreover, in the NASH patients, hypolactasia was an independent risk factor for insulin resistance even after adjusting for gender and age [OR = 5.0 (95%CI: 1.35-20; P = 0.017)]. CONCLUSION The LCT-13910 genotype distribution in Brazilian NAFLD patients was the same as that of the general population, but hypolactasia increased the risk of insulin resistance in the NASH patients. PMID:27648154

PERSISTENCE OF PHARMACEUTICALS AND OTHER WASTEWATER RELATED COMPOUNDS

EPA Science Inventory

The quality of drinking and recreational water is currently ascertained using indicator bacteria. However, the tests to analyze for these bacteria require a considerable length of time to complete, and do not discriminate between human and animal fecal material sources. One sol...

Length Is Associated with Pain: Jellyfish with Painful Sting Have Longer Nematocyst Tubules than Harmless Jellyfish.

PubMed

Kitatani, Ryuju; Yamada, Mayu; Kamio, Michiya; Nagai, Hiroshi

2015-01-01

A large number of humans are stung by jellyfish all over the world. The stings cause acute pain followed by persistent pain and local inflammation. Harmful jellyfish species typically cause strong pain, whereas harmless jellyfish cause subtle or no pain. Jellyfish sting humans by injecting a tubule, contained in the nematocyst, the stinging organ of jellyfish. The tubule penetrates into the skin leading to venom injection. The detailed morphology of the nematocyst tubule and molecular structure of the venom in the nematocyst has been reported; however, the mechanism responsible for the difference in pain that is caused by harmful and harmless jellyfish sting has not yet been explored or explained. Therefore, we hypothesized that differences in the length of the nematocyst tubule leads to different degrees of epithelial damage. The initial acute pain might be generated by penetration of the tubule, which stimulates pain receptor neurons, whilst persistent pain might be caused by injection of venom into the epithelium. To test this hypothesis we compared the lengths of discharged nematocyst tubules from harmful and harmless jellyfish species and evaluated their ability to penetrate human skin. The results showed that the harmful jellyfish species, Chrysaora pacifica, Carybdea brevipedalia, and Chironex yamaguchii, causing moderate to severe pain, have nematocyst tubules longer than 200 μm, compared with a jellyfish species that cause little or no pain, Aurelia aurita. The majority of the tubules of harmful jellyfishes, C. yamaguchii and C. brevipedalia, were sufficiently long to penetrate the human epidermis and physically stimulate the free nerve endings of Aδ pain receptor fibers around plexuses to cause acute pain and inject the venom into the human skin epithelium to cause persistent pain and inflammation.

Behavioral and biochemical adjustments of the zebrafish Danio rerio exposed to the β-blocker propranolol.

PubMed

Mitchell, Kimberly M; Moon, Thomas W

2016-09-01

Propranolol (PROP) is a β-blocker prescribed mainly to treat human cardiovascular diseases and as a result of its wide usage and persistence, it is reported in aquatic environments. This study examined whether PROP alters developmental patterns and catecholamine (CA)-regulated processes in the zebrafish (Danio rerio) and if exposure during early life alters the stress response and behaviors of adults. The calculated 48h larva LC50 was 21.6mg/L, well above reported environmental levels (0.01-0.59μg/L). Stressed and PROP-exposed adult zebrafish had reduced testosterone and estradiol levels and exhibited behaviors indicating less anxiety than control fish. Furthermore, adults previously PROP-exposed as embryos/larvae had decreased growth in terms of body length and mass. Finally, these adults showed increased cholesterol and a dose-dependent decrease in testosterone levels compared with unexposed zebrafish. Thus PROP-exposure of zebrafish embryos/larvae alters developmental patterns and CA-regulated processes that may affect normal behaviors and responses to stressors, and at least some of these changes persist in the adult zebrafish. Copyright © 2015 Elsevier Inc. All rights reserved.

Serratia marcescens in a neonatal intensive care unit: two long-term multiclone outbreaks in a 10-year observational study.

PubMed

Casolari, Chiara; Pecorari, Monica; Della Casa, Elisa; Cattani, Silvia; Venturelli, Claudia; Fabio, Giuliana; Tagliazucchi, Sara; Serpini, Giulia Fregni; Migaldi, Mario; Marchegiano, Patrizia; Rumpianesi, Fabio; Ferrari, Fabrizio

2013-10-01

We investigated two consecutive Serratia marcescens (S. marcescens) outbreaks which occurred in a neonatal intensive care unit (NICU) of a tertiary level hospital in North Italy in a period of 10 years (January 2003-December 2012). Risk factors associated with S. marcescens acquisition were evaluated by a retrospective case-control study. A total of 21,011 clinical samples was examined: S. marcescens occurred in 127 neonates: 43 developed infection and 3 died. Seven clusters were recorded due to 12 unrelated clones which persisted for years in the ward, although no environmental source was found. The main epidemic clone A sustaining the first cluster in 2003 reappeared in 2010 as an extended spectrum ?-lactamase (ESBL)-producing strain and supporting the second epidemic. Birth weight, gestational age, use of invasive devices and length of stay in the ward were significantly related to S. marcescens acquisition. The opening of a new ward for non-intensive care-requiring neonates, strict adherence to alcoholic hand disinfection, the timely identification and isolation of infected and colonized neonates assisted in containing the epidemics. Genotyping was effective in tracing the evolution and dynamics of the clones demonstrating their long-term persistence in the ward.

Biodiesel presence in the source zone hinders aromatic hydrocarbons attenuation in a B20-contaminated groundwater

NASA Astrophysics Data System (ADS)

Ramos, Débora Toledo; Lazzarin, Helen Simone Chiaranda; Alvarez, Pedro J. J.; Vogel, Timothy M.; Fernandes, Marilda; do Rosário, Mário; Corseuil, Henry Xavier

2016-10-01

The behavior of biodiesel blend spills have received limited attention in spite of the increasing and widespread introduction of biodiesel to the transportation fuel matrix. In this work, a controlled field release of biodiesel B20 (100 L of 20:80 v/v soybean biodiesel and diesel) was monitored over 6.2 years to assess the behavior and natural attenuation of constituents of major concern (e.g., BTEX (benzene, toluene, ethyl-benzene and xylenes) and PAHs (polycyclic aromatic hydrocarbons)) in a sandy aquifer material. Biodiesel was preferentially biodegraded compared to diesel aromatic compounds with a concomitant increase in acetate, methane (near saturation limit (≈ 22 mg L- 1)) and dissolved BTEX and PAH concentrations in the source zone during the first 1.5 to 2.0 years after the release. Benzene and benzo(a)pyrene concentrations remained above regulatory limits in the source zone until the end of the experiment (6.2 years after the release). Compared to a previous adjacent 100-L release of ethanol-amended gasoline, biodiesel/diesel blend release resulted in a shorter BTEX plume, but with higher residual dissolved hydrocarbon concentrations near the source zone. This was attributed to greater persistence of viscous (and less mobile) biodiesel than the highly-soluble and mobile ethanol in the source zone. This persistence of biodiesel/diesel NAPL at the source zone slowed BTEX and PAH biodegradation (by the establishment of an anaerobic zone) but reduced the plume length by reducing mobility. This is the first field study to assess biodiesel/diesel blend (B20) behavior in groundwater and its effects on the biodegradation and plume length of priority groundwater pollutants.

Biodiesel presence in the source zone hinders aromatic hydrocarbons attenuation in a B20-contaminated groundwater.

PubMed

Ramos, Débora Toledo; Lazzarin, Helen Simone Chiaranda; Alvarez, Pedro J J; Vogel, Timothy M; Fernandes, Marilda; do Rosário, Mário; Corseuil, Henry Xavier

2016-10-01

The behavior of biodiesel blend spills have received limited attention in spite of the increasing and widespread introduction of biodiesel to the transportation fuel matrix. In this work, a controlled field release of biodiesel B20 (100L of 20:80 v/v soybean biodiesel and diesel) was monitored over 6.2years to assess the behavior and natural attenuation of constituents of major concern (e.g., BTEX (benzene, toluene, ethyl-benzene and xylenes) and PAHs (polycyclic aromatic hydrocarbons)) in a sandy aquifer material. Biodiesel was preferentially biodegraded compared to diesel aromatic compounds with a concomitant increase in acetate, methane (near saturation limit (≈22mgL -1 )) and dissolved BTEX and PAH concentrations in the source zone during the first 1.5 to 2.0years after the release. Benzene and benzo(a)pyrene concentrations remained above regulatory limits in the source zone until the end of the experiment (6.2years after the release). Compared to a previous adjacent 100-L release of ethanol-amended gasoline, biodiesel/diesel blend release resulted in a shorter BTEX plume, but with higher residual dissolved hydrocarbon concentrations near the source zone. This was attributed to greater persistence of viscous (and less mobile) biodiesel than the highly-soluble and mobile ethanol in the source zone. This persistence of biodiesel/diesel NAPL at the source zone slowed BTEX and PAH biodegradation (by the establishment of an anaerobic zone) but reduced the plume length by reducing mobility. This is the first field study to assess biodiesel/diesel blend (B20) behavior in groundwater and its effects on the biodegradation and plume length of priority groundwater pollutants. Copyright © 2016 Elsevier B.V. All rights reserved.

Persistence of identifiable remains of white sturgeon juveniles in digestive tracts of northern pikeminnow

USGS Publications Warehouse

Gadomski, D.M.; Frost, C.N.

2004-01-01

Juvenile white sturgeon, Acipenser transmontanus, have not been commonly identified as prey items in digestive tracts of fishes collected in the wild. In particular, the diet of northern pikeminnow, Ptychocheilus oregonensis, an abundant Pacific Northwest freshwater predator which has been widely studied, has not included juvenile white sturgeon. To aid in interpreting these results and help in planning future feeding studies, we determined the persistence of identifiable remains of white sturgeon juveniles in this predator's digestive tract. Northern pikeminnow (mean total length = 476 mm), were force-fed meals of 2 or 3 juvenile white sturgeon (mean total length = 91 mm). After digestive periods of 4, 8, 16, 24, 28, and 32h at a water temperature of about 17 ??C, fish were sacrificed, digestive tracts removed, and contents examined. Our results indicate that juvenile white sturgeon would be readily discernable in digestive tracts of northern pikeminnow at least a day after feeding, with scutes remaining undigested and identifiable for 28 h.

DNA motion capture reveals the mechanical properties of DNA at the mesoscale.

PubMed

Price, Allen C; Pilkiewicz, Kevin R; Graham, Thomas G W; Song, Dan; Eaves, Joel D; Loparo, Joseph J

2015-05-19

Single-molecule studies probing the end-to-end extension of long DNAs have established that the mechanical properties of DNA are well described by a wormlike chain force law, a polymer model where persistence length is the only adjustable parameter. We present a DNA motion-capture technique in which DNA molecules are labeled with fluorescent quantum dots at specific sites along the DNA contour and their positions are imaged. Tracking these positions in time allows us to characterize how segments within a long DNA are extended by flow and how fluctuations within the molecule are correlated. Utilizing a linear response theory of small fluctuations, we extract elastic forces for the different, ∼2-μm-long segments along the DNA backbone. We find that the average force-extension behavior of the segments can be well described by a wormlike chain force law with an anomalously small persistence length. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

In Silico Measurements of Twist and Bend Moduli for β-Solenoid Protein Self-Assembly Units.

PubMed

Heinz, Leonard P; Ravikumar, Krishnakumar M; Cox, Daniel L

2015-05-13

We compute potentials of mean force for bend and twist deformations via force pulling and umbrella sampling experiments for four β-solenoid proteins (BSPs) that show promise in nanotechnology applications. In all cases, we find quasi-Hooke's law behavior until the point of rupture. Bending moduli show modest anisotropy for two-sided and three-sided BSPs, and little anisotropy for a four-sided BSP. There is a slight clockwise/counterclockwise asymmetry in the twist potential of mean force, showing greater stiffness when the applied twist follows the intrinsic twist. When we extrapolate to beam theory appropriate for amyloid fibrils of the BSPs, we find bend/twist moduli which are somewhat smaller than those in the literature for other amyloid fibrils. Twist persistence lengths are on the order of a micron, and bend persistence lengths are several microns. Provided the intrinsic twist can be reversed, these results support the usage of BSPs in biomaterials applications.

Persistent-random-walk approach to anomalous transport of self-propelled particles

NASA Astrophysics Data System (ADS)

Sadjadi, Zeinab; Shaebani, M. Reza; Rieger, Heiko; Santen, Ludger

2015-06-01

The motion of self-propelled particles is modeled as a persistent random walk. An analytical framework is developed that allows the derivation of exact expressions for the time evolution of arbitrary moments of the persistent walk's displacement. It is shown that the interplay of step length and turning angle distributions and self-propulsion produces various signs of anomalous diffusion at short time scales and asymptotically a normal diffusion behavior with a broad range of diffusion coefficients. The crossover from the anomalous short-time behavior to the asymptotic diffusion regime is studied and the parameter dependencies of the crossover time are discussed. Higher moments of the displacement distribution are calculated and analytical expressions for the time evolution of the skewness and the kurtosis of the distribution are presented.

Gestational weight gain and predicted changes in offspring anthropometrics between early infancy and 3 years.

PubMed

Deierlein, A L; Siega-Riz, A M; Herring, A H; Adair, L S; Daniels, J L

2012-04-01

To determine how gestational weight gain (GWG), categorized using the 2009 Institute of Medicine recommendations, relates to changes in offspring weight-for-age (WAZ), length-for-age (LAZ) and weight-for-length z-scores (WLZ) between early infancy and 3 years. Women with singleton infants were recruited from the third cohort of the Pregnancy, Infection, and Nutrition Study (2001-2005). Term infants with at least one weight or length measurement during the study period were included (n = 476). Multivariable linear mixed effects regression models estimated longitudinal changes in WAZ, LAZ and WLZ associated with GWG. In early infancy, compared with infants of women with adequate weight gain, those of women with excessive weight gains had higher WAZ, LAZ and WLZ. Excessive GWG ≥ 200% of the recommended amount was associated with faster rates of change in WAZ and LAZ and noticeably higher predicted mean WAZ and WLZ that persisted across the study period. GWG is associated with significant differences in offspring anthropometrics in early infancy that persisted to 3 years of age. More longitudinal studies that utilize maternal and paediatric body composition measures are necessary to understand the nature of this association. © 2012 The Authors. Pediatric Obesity © 2012 International Association for the Study of Obesity.

Mode-coupling theory for active Brownian particles

NASA Astrophysics Data System (ADS)

Liluashvili, Alexander; Ónody, Jonathan; Voigtmann, Thomas

2017-12-01

We present a mode-coupling theory (MCT) for the slow dynamics of two-dimensional spherical active Brownian particles (ABPs). The ABPs are characterized by a self-propulsion velocity v0 and by their translational and rotational diffusion coefficients Dt and Dr, respectively. Based on the integration-through-transients formalism, the theory requires as input only the equilibrium static structure factors of the passive system (where v0=0 ). It predicts a nontrivial idealized-glass-transition diagram in the three-dimensional parameter space of density, self-propulsion velocity, and rotational diffusivity that arise because at high densities, the persistence length of active swimming ℓp=v0/Dr interferes with the interaction length ℓc set by the caging of particles. While the low-density dynamics of ABPs is characterized by a single Péclet number Pe=v02/DrDt , close to the glass transition the dynamics is found to depend on Pe and ℓp separately. At fixed density, increasing the self-propulsion velocity causes structural relaxation to speed up, while decreasing the persistence length slows down the relaxation. The active-MCT glass is a nonergodic state that is qualitatively different from the passive glass. In it, correlations of initial density fluctuations never fully decay, but also an infinite memory of initial orientational fluctuations is retained in the positions.

Electrostatic persistence length.

PubMed

Fixman, Marshall

2010-03-11

The persistence length is calculated for polyelectrolyte chains with fixed bond lengths and bond angles (pi-theta), and a potential energy consisting of the screened Coulomb interaction between beads, potential wells alpha phi(i)2 for the dihedral angles phi(i), and coupling terms beta phi(i) phi(i+/-1). This model defines a librating chain that reduces in appropriate limits to the freely rotating or wormlike chains, it can accommodate local crumpling or extreme stiffness, and it is easy to simulate. A planar-quadratic (pq), analytic approximation is based on an expansion of the electrostatic energy in eigenfunctions of the quadratic form that describes the backbone energy, and on the assumption that the quadratic form not only is positive but also adequately confines the chain in an infinite phase space of dihedral angles to the physically unique part with all |phi(i)| < pi. The pq approximation is available under these weak constraints, but the simulations confirm its quantitative accuracy only under the expected condition that alpha is large, that is, for very stiff chains. Stiff chains can also be simulated with small alpha and small theta and compared to an OSF approximation suitably generalized to chains with finite rather than vanishing theta, and increasing agreement with OSF is found the smaller is theta. The two approximations, one becoming exact as alpha --> infinity with fixed theta, the other as theta --> 0 with fixed alpha, are quantitatively similar in behavior, both giving a persistence length P = P0 + aD2 for stiff chains, where D is the Debye length. However, the coefficient apq is about twice the value of aOSF. Under other conditions the simulations show that P may or not be linear in D2 at small or moderate D, depending on the magnitudes of alpha, beta, theta, and the charge density but always becomes linear at large D. Even at a moderately low charge density, corresponding to fewer than 20% of the beads being charged, and with strong crumpling induced by large beta, increasing D dissolves blobs and recovers a linear dependence of P on D2, although a lower power of D gives an adequate fit at moderate D. For the class of models considered, it is concluded that the only universal feature is the asymptotic linearity of P in D2, regardless of flexibility or stiffness.

Stretchable Persistent Spin Helices in GaAs Quantum Wells

NASA Astrophysics Data System (ADS)

Dettwiler, Florian; Fu, Jiyong; Mack, Shawn; Weigele, Pirmin J.; Egues, J. Carlos; Awschalom, David D.; Zumbühl, Dominik M.

2017-07-01

The Rashba and Dresselhaus spin-orbit (SO) interactions in 2D electron gases act as effective magnetic fields with momentum-dependent directions, which cause spin decay as the spins undergo arbitrary precessions about these randomly oriented SO fields due to momentum scattering. Theoretically and experimentally, it has been established that by fine-tuning the Rashba α and renormalized Dresselhaus β couplings to equal fixed strengths α =β , the total SO field becomes unidirectional, thus rendering the electron spins immune to decay due to momentum scattering. A robust persistent spin helix (PSH), i.e., a helical spin-density wave excitation with constant pitch P =2 π /Q , Q =4 m α /ℏ2, has already been experimentally realized at this singular point α =β , enhancing the spin lifetime by up to 2 orders of magnitude. Here, we employ the suppression of weak antilocalization as a sensitive detector for matched SO fields together with independent electrical control over the SO couplings via top gate voltage VT and back gate voltage VB to extract all SO couplings when combined with detailed numerical simulations. We demonstrate for the first time the gate control of the renormalized β and the continuous locking of the SO fields at α =β ; i.e., we are able to vary both α and β controllably and continuously with VT and VB, while keeping them locked at equal strengths. This makes possible a new concept: "stretchable PSHs," i.e., helical spin patterns with continuously variable pitches P over a wide parameter range. Stretching the PSH, i.e., gate controlling P while staying locked in the PSH regime, provides protection from spin decay at the symmetry point α =β , thus offering an important advantage over other methods. This protection is limited mainly by the cubic Dresselhaus term, which breaks the unidirectionality of the total SO field and causes spin decay at higher electron densities. We quantify the cubic term, and find it to be sufficiently weak so that the extracted spin-diffusion lengths and decay times show a significant enhancement near α =β . Since within the continuous-locking regime quantum transport is diffusive (2D) for charge while ballistic (1D) for spin and thus amenable to coherent spin control, stretchable PSHs could provide the platform for the much heralded long-distance communication ˜8 - 25 μ m between solid-state spin qubits, where the spin diffusion length for α ≠β is an order of magnitude smaller.

Unique characteristics of motor adaptation during walking in young children.

PubMed

Musselman, Kristin E; Patrick, Susan K; Vasudevan, Erin V L; Bastian, Amy J; Yang, Jaynie F

2011-05-01

Children show precocious ability in the learning of languages; is this the case with motor learning? We used split-belt walking to probe motor adaptation (a form of motor learning) in children. Data from 27 children (ages 8-36 mo) were compared with those from 10 adults. Children walked with the treadmill belts at the same speed (tied belt), followed by walking with the belts moving at different speeds (split belt) for 8-10 min, followed again by tied-belt walking (postsplit). Initial asymmetries in temporal coordination (i.e., double support time) induced by split-belt walking were slowly reduced, with most children showing an aftereffect (i.e., asymmetry in the opposite direction to the initial) in the early postsplit period, indicative of learning. In contrast, asymmetries in spatial coordination (i.e., center of oscillation) persisted during split-belt walking and no aftereffect was seen. Step length, a measure of both spatial and temporal coordination, showed intermediate effects. The time course of learning in double support and step length was slower in children than in adults. Moreover, there was a significant negative correlation between the size of the initial asymmetry during early split-belt walking (called error) and the aftereffect for step length. Hence, children may have more difficulty learning when the errors are large. The findings further suggest that the mechanisms controlling temporal and spatial adaptation are different and mature at different times.

Predicting persistence to antidepressant treatment in administrative claims data: Considering the influence of refill delays and prior persistence on other medications

PubMed Central

Bushnell, Greta A; Stürmer, Til; White, Alice; Pate, Virginia; Swanson, Sonja A; Azrael, Deborah; Miller, Matthew

2016-01-01

Background Many patients with major depressive disorder (MDD) who begin antidepressant treatment discontinue use before for six months, the recommended minimum treatment length. This study sought to identify predictors of six-month antidepressant persistence including predictors utilizing patients’ electronic prescription records. Methods Commercially insured children (3–17 years) and adults (18–64 years) with MDD who initiated antidepressant treatment, 1/1/2003–2/28/2010, were assessed for six-month persistence (based on prescriptions’ days supply, allowing a 30-day grace period). Antidepressant persistence prediction models were developed separately for children and adults. Two additional measures, days without medication between the first and second antidepressant fill (children and adults) and prior persistence on other medications (adults only), were added to the models, concordance (c) statistics were compared and risk reclassification evaluated. Results Among children (n=8,837 children) and adults (n=47,495) with MDD, six-month antidepressant persistence was low and varied by age (37%, 18–24 years to 52%, 3–12 and 50–64 years, respectively). Independent baseline predictors of persistence were identified, with model c-statistics: children=0.582, adults=0.584. Patients with more days without medication between fills were less likely to be persistent (10–30 vs. 0 days, children: RR=0.72, adults: RR=0.74), as were adults not previously persistent to other medications (RR=0.73). Limitations The definition of 6-month persistence is dependent on correct days supply values and the grace period utilized; potential predictors were limited to measures available in claims data. Conclusions Six-month antidepressant persistence was low and overall prediction of persistence was poor; however, days without medication between fills and prior persistence on other medications marginally improved the ability to predict antidepressant persistence. PMID:26921866

Activation of mouse and human peroxisome proliferator-activated receptor alpha by perfluoroalkyl acids of different functional groups and chain lengths.

PubMed

Wolf, Cynthia J; Takacs, Margy L; Schmid, Judith E; Lau, Christopher; Abbott, Barbara D

2008-11-01

Perfluoroalkyl acids (PFAAs) are surfactants used in consumer products and persist in the environment. Some PFAAs elicit adverse effects on rodent development and survival. PFAAs can activate peroxisome proliferator-activated receptor alpha (PPARalpha) and may act via PPARalpha to produce some of their effects. This study evaluated the ability of numerous PFAAs to induce mouse and human PPARalpha activity in a transiently transfected COS-1 cell assay. COS-1 cells were transfected with either a mouse or human PPARalpha receptor-luciferase reporter plasmid. After 24 h, cells were exposed to either negative controls (water or dimethyl sulfoxide, 0.1%); positive control (WY-14643, PPARalpha agonist); perfluorooctanoic acid or perfluorononanoic acid at 0.5-100 microM; perfluorobutanoic acid, perfluorohexanoic acid, perfluorohexane sulfonate, or perfluorodecanoic acid (PFDA) at 5-100 microM; or perfluorobutane sulfonate or perfluorooctane sulfonate at 1-250 microM. After 24 h of exposure, luciferase activity from the plasmid was measured. Each PFAA activated both mouse and human PPARalpha in a concentration-dependent fashion, except PFDA with human PPARalpha. Activation of PPARalpha by PFAA carboxylates was positively correlated with carbon chain length, up to C9. PPARalpha activity was higher in response to carboxylates compared to sulfonates. Activation of mouse PPARalpha was generally higher compared to that of human PPARalpha. We conclude that, in general, (1) PFAAs of increasing carbon backbone chain lengths induce increasing activity of the mouse and human PPARalpha with a few exceptions, (2) PFAA carboxylates are stronger activators of mouse and human PPARalpha than PFAA sulfonates, and (3) in most cases, the mouse PPARalpha appears to be more sensitive to PFAAs than the human PPARalpha in this model.

Finite size scaling analysis on Nagel-Schreckenberg model for traffic flow

NASA Astrophysics Data System (ADS)

Balouchi, Ashkan; Browne, Dana

2015-03-01

The traffic flow problem as a many-particle non-equilibrium system has caught the interest of physicists for decades. Understanding the traffic flow properties and though obtaining the ability to control the transition from the free-flow phase to the jammed phase plays a critical role in the future world of urging self-driven cars technology. We have studied phase transitions in one-lane traffic flow through the mean velocity, distributions of car spacing, dynamic susceptibility and jam persistence -as candidates for an order parameter- using the Nagel-Schreckenberg model to simulate traffic flow. The length dependent transition has been observed for a range of maximum velocities greater than a certain value. Finite size scaling analysis indicates power-law scaling of these quantities at the onset of the jammed phase.

An origin-deficient yeast artificial chromosome triggers a cell cycle checkpoint.

PubMed

van Brabant, A J; Buchanan, C D; Charboneau, E; Fangman, W L; Brewer, B J

2001-04-01

Checkpoint controls coordinate entry into mitosis with the completion of DNA replication. Depletion of nucleotide precursors by treatment with the drug hydroxyurea triggers such a checkpoint response. However, it is not clear whether the signal for this hydroxyurea-induced checkpoint pathway is the presence of unreplicated DNA, or rather the persistence of single-stranded or damaged DNA. In a yeast artificial chromosome (YAC) we have engineered an approximately 170 kb region lacking efficient replication origins that allows us to explore the specific effects of unreplicated DNA on cell cycle progression. Replication of this YAC extends the length of S phase and causes cells to engage an S/M checkpoint. In the absence of Rad9 the YAC becomes unstable, undergoing deletions within the origin-free region.

Evaluating linear response in active systems with no perturbing field

NASA Astrophysics Data System (ADS)

Szamel, Grzegorz

2017-03-01

We present a method for the evaluation of time-dependent linear response functions for systems of active particles propelled by a persistent (colored) noise from unperturbed simulations. The method is inspired by the Malliavin weights sampling method proposed by Warren and Allen (Phys. Rev. Lett., 109 (2012) 250601) for out-of-equilibrium systems of passive Brownian particles. We illustrate our method by evaluating two linear response functions for a single active particle in an external harmonic potential. As an application, we calculate the time-dependent mobility function and an effective temperature, defined through the Einstein relation between the self-diffusion and mobility coefficients, for a system of many active particles interacting via a screened Coulomb potential. We find that this effective temperature decreases with increasing persistence time of the self-propulsion. Initially, for not too large persistence times, it changes rather slowly, but then it decreases markedly when the persistence length of the self-propelled motion becomes comparable with the particle size.

Evaluating linear response in active systems with no perturbing field: Application to the calculation of an effective temperature

NASA Astrophysics Data System (ADS)

Szamel, Grzegorz

We present a method for the evaluation of time-dependent linear response functions for systems of active particles propelled by a persistent (colored) noise from unperturbed simulations. The method is inspired by the Malliavin weights sampling method proposed earlier for systems of (passive) Brownian particles. We illustrate our method by evaluating a linear response function for a single active particle in an external harmonic potential. As an application, we calculate the time-dependent mobility function and an effective temperature, defined through the Einstein relation between the self-diffusion and mobility coefficients, for a system of active particles interacting via a screened-Coulomb potential. We find that this effective temperature decreases with increasing persistence time of the self-propulsion. Initially, for not too large persistence times, it changes rather slowly, but then it decreases markedly when the persistence length of the self-propelled motion becomes comparable with the particle size. Supported by NSF and ERC.

Behavioral, morphometric, and gene expression effects in adult zebrafish (Danio rerio) embryonically exposed to PFOA, PFOS, and PFNA.

PubMed

Jantzen, Carrie E; Annunziato, Kate M; Cooper, Keith R

2016-11-01

Perfluoroalkylated substances (PFAS) are a class of persistent anthropogenic chemicals that have been detected worldwide. PFASs consist of fluorinated carbon chains of varying length, terminal groups, and have a number of industrial uses. A previous zebrafish study from our laboratory showed that acute (3-120h post fertilization, 0.02-2.0μM), waterborne embryonic exposure to these chemicals resulted in chemical specific alterations at 5days post fertilization (dpf), and some effects persisted up to 14 dpf. Using a gene battery consisting of 100 transcripts identified several genes that were up or down regulated. This current study looks at the long-term impacts of PFASs in adult zebrafish using the same exposure regimen. It was hypothesized that sub-lethal exposure of perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), or perfluorooctane sulfonate (PFOA) in embryonic zebrafish (3-120 hpf) would result in permanent morphometric, gene expression, and behavioral changes in adult fish similar to those observed at 5 and 14 dpf. Zebrafish were exposed to PFOS, PFOA, and PFNA (Control 0μM, 2.0μM) for the first five days post fertilization. At six months post fertilization, no PFAS treatment resulted in a significant change in total body length or weight. In terms of behavior, PFNA males showed a reduction in total distance traveled and time of immobility, and an increase in thigmotaxis behavior, aggressive attacks, and preference for the bright section of the tank. PFOS treated males had a reduced aggression behavior, and PFOA females preferred the dark section of the tank. Gene expression of slco2b1, slco1d1, and tgfb1a were analyzed because these transcripts were previously found to be affected by PFAS exposure in 5dpf and 14 dpf zebrafish and resulted in: significant decrease in expression of slco2b1 for both sexes in PFNA and PFOS treated groups, significant decrease of slco1d1 in all treatment groups for females and PFOS and PFOA exposed males, significant increase of tgfb1a in males treated with PFOS and PFNA, and a significant increase of bdnf in all PFAS male groups. This study demonstrates that acute, embryonic exposure (5days) to individual PFASs result in significant biochemical and behavioral changes in young adult zebrafish 6 months after exposure. These three PFASs have long term and persistent impacts following short term embryonic exposure that persists into adulthood. Copyright © 2016 Elsevier B.V. All rights reserved.

Interaction Between Ecohydrologic Dynamics and Microtopographic Variability Under Climate Change

NASA Astrophysics Data System (ADS)

Le, Phong V. V.; Kumar, Praveen

2017-10-01

Vegetation acclimation resulting from elevated atmospheric CO2 concentration, along with response to increased temperature and altered rainfall pattern, is expected to result in emergent behavior in ecologic and hydrologic functions. We hypothesize that microtopographic variability, which are landscape features typically of the length scale of the order of meters, such as topographic depressions, will play an important role in determining this dynamics by altering the persistence and variability of moisture. To investigate these emergent ecohydrologic dynamics, we develop a modeling framework, Dhara, which explicitly incorporates the control of microtopographic variability on vegetation, moisture, and energy dynamics. The intensive computational demand from such a modeling framework that allows coupling of multilayer modeling of the soil-vegetation continuum with 3-D surface-subsurface flow processes is addressed using hybrid CPU-GPU parallel computing framework. The study is performed for different climate change scenarios for an intensively managed agricultural landscape in central Illinois, USA, which is dominated by row-crop agriculture, primarily soybean (Glycine max) and maize (Zea mays). We show that rising CO2 concentration will decrease evapotranspiration, thus increasing soil moisture and surface water ponding in topographic depressions. However, increased atmospheric demand from higher air temperature overcomes this conservative behavior resulting in a net increase of evapotranspiration, leading to reduction in both soil moisture storage and persistence of ponding. These results shed light on the linkage between vegetation acclimation under climate change and microtopography variability controls on ecohydrologic processes.

Persistent anxiety and in-hospital complications after acute coronary syndrome

PubMed Central

AbuRuz, Mohannad Eid

2018-01-01

Objectives: To investigate the effects of pre-event persistent anxiety on in-hospital complications and length of stay (LOS) in patients who experienced acute coronary syndrome (ACS). Methods: This was a prospective study with patients seeking treatment for ACS events. Anxiety was measured 2 times before the event in 600 patients with pre-existing coronary heart disease (CHD). Patients were followed for 2 years or until they developed an ACS event. 120 patients developed ACS events (rate 20%). Complications and LOS were abstracted from medical records. Results: Persistently non-anxious patients have lower anxiety scores at 3 months follow-up than baseline (mean [standard deviation (SD)], 6.1 [0.24] vs. 3.9 [0.95], P <0.01). Patients with persistent anxiety had significantly higher complication rates than non-anxious patients (mean [SD], 0.71 [0.12] vs. 0.15 [0.11], P <0.05). In a multiple logistic regression, persistent anxiety was an independent predictor of complications. Patients who were persistently anxious were at 5 times higher risk for developing complications (odds ratio = 5.0, 95% confidence interval: 1.27–38.8, P < 0.05). Conclusion: Anxiety measured up to 2 years before an ACS event was predictive of in-hospital complications. Clinicians caring for patients with CHD need to be as equally aware of the importance of assessing and treating persistent anxiety as clinicians caring for patients hospitalized for an ACS. PMID:29599695

Persistence of Rift Valley fever virus in East Africa

NASA Astrophysics Data System (ADS)

Gachohi, J.; Hansen, F.; Bett, B.; Kitala, P.

2012-04-01

Rift Valley fever virus (RVFv) is a mosquito-borne pathogen of livestock, wildlife and humans that causes severe outbreaks in intervals of several years. One of the open questions is how the virus persists between outbreaks. We developed a spatially-explicit, individual-based simulation model of the RVFv transmission dynamics to investigate this question. The model, is based on livestock and mosquito population dynamics. Spatial aspects are explicitly represented by a set of grid cells that represent mosquito breeding sites. A grid cell measures 500 by 500m and the model considers a grid of 100 by 100 grid cells; the model thus operates on the regional scale of 2500km2. Livestock herds move between grid cells, and provide connectivity between the cells. The model is used to explore the spatio-temporal dynamics of RVFv persistence in absence of a wildlife reservoir in an east African semi-arid context. Specifically, the model assesses the importance of local virus persistence in mosquito breeding sites relative to global virus persistence mitigated by movement of hosts. Local persistence is determined by the length of time the virus remains in a mosquito breeding site once introduced. In the model, this is a function of the number of mosquitoes that emerge infected and their lifespan. Global persistence is determined by the level of connectivity between isolated grid cells. Our work gives insights into the ecological and epidemiological conditions under which RVFv persists. The implication for disease surveillance and management are discussed.

The Wage Gap and Administrative Salaries Today.

ERIC Educational Resources Information Center

Beyer, Kirk D.

1992-01-01

Analysis of national data on college administrator salaries by gender, minority/nonminority status, years of service, and institution type found that wage gaps related to gender and minority status persisted in 1991-92 but that interaction of length of service with other study variables explained a significant amount of this gap. (MSE)

Space fabrication demonstration system

NASA Technical Reports Server (NTRS)

1978-01-01

The lower right aluminum beam cap roll forming mill was delivered and installed in the beam builder. The beam was brought to full operational status and beams of one to six bay lengths were produced to demonstrate full system capability. Although the cap flange waviness problem persists, work is progressing within cost and schedule.

PERSISTENCE OF PHARMACEUTICALS AND OTHER WASTEWATER RELATED COMPOUNDS: UTILITY AS INDICATORS OF HUMAN FECAL CONTAMINATION

EPA Science Inventory

The quality of drinking and recreational water is currently ascertained using indicator bacteria. The tests to analyze for these bacteria require a considerable length of time to complete, and do not discriminate between human and animal fecal material sources. To shorten the t...

Corridor Length and Patch Colonization by a Butterfly, Junonia coenia

Treesearch

Nick Haddad

2000-01-01

Corridors have been proposed to reduce isolation and increase population persistence in fragmented landscapes, yet little research has evaluated the types of landscapes in which corridors will be most effective. I tested the hypothesis that corridors increase patch colonization by a butterfly, Junonia coenia, regardless of the butterfly's...

SUBCLINICAL INFECTION OF DOGS BY CANINE-ADAPTED MEASLES VIRUS EVIDENCED BY THEIR SUBSEQUENT IMMUNITY TO CANINE DISTEMPER VIRUS

PubMed Central

Moura, Roberto A.; Warren, Joel

1961-01-01

Moura, Roberto A. (Chas. Pfizer and Company, Inc., Terre Haute, Ind.) and Joel Warren. Subclinical infection of dogs by canine-adapted measles virus evidenced by their subsequent immunity to canine distemper virus. J. Bacteriol. 82:702–705. 1961.—Young dogs were inoculated with virulent measles virus which had been adapted to canine kidney or human amnion cell culture. None of the animals showed any clinical symptoms nor could virus be isolated from the blood, although measles-neutralizing and complement-fixing antibodies developed during convalescence. All dogs failed to develop antibody to canine distemper. However, when these and normal control animals were subsequently inoculated intracerebrally with virulent distemper virus, each of the controls succumbed to typical symptoms, whereas all of the measles-immune dogs survived. These results suggest that the cross-protection conferred by measles against canine distemper virus infection involves factors other than humoral antibody. The immunity persists for a considerable length of time. PMID:14476677

Evidence for a pre-existing telomere deficit in non-clonal hematopoietic stem cells in patients with acute myeloid leukemia.

PubMed

Ventura Ferreira, Mónica S; Crysandt, Martina; Ziegler, Patrick; Hummel, Sebastian; Wilop, Stefan; Kirschner, Martin; Schemionek, Mirle; Jost, Edgar; Wagner, Wolfgang; Brümmendorf, Tim H; Beier, Fabian

2017-09-01

Telomere shortening represents an established mechanism connecting aging and cancer development. We sequentially analyzed telomere length (TL) of 49 acute myeloid leukemia (AML) patients at diagnosis (n = 24), once they achieved complete cytological remission (CCR) and/or during refractory disease or relapse and after 1-year follow-up, with all patients having at least two sequential samples. TL was analyzed by monochrome multiplex quantitative polymerase chain reaction. We have observed substantially shortened TL in the cells of patients at diagnosis compared to age-adjusted controls. In patients reaching CCR after chemotherapy, telomere shortening was less pronounced than in persistence or relapse but still significantly shortened compared to controls. We estimate patients harboring approximately 20 years of premature telomere loss compared to healthy aged-matched subjects at the time of AML onset. Our data indicate a pre-existing telomere deficit in non-clonal hematopoiesis of AML patients providing a link between age and AML development.

Improvement in Growth After 1 Year of Growth Hormone Therapy in Well-Nourished Infants with Growth Retardation Secondary to Chronic Renal Failure: Results of a Multicenter, Controlled, Randomized, Open Clinical Trial

PubMed Central

Moreno, M. Llanos; Neto, Arlete; Ariceta, Gema; Vara, Julia; Alonso, Angel; Bueno, Alberto; Afonso, Alberto Caldas; Correia, António Jorge; Muley, Rafael; Barrios, Vicente; Gómez, Carlos; Argente, Jesús

2010-01-01

Background and objectives: Our aim was to evaluate the growth-promoting effect of growth hormone (GH) treatment in infants with chronic renal failure (CRF) and persistent growth retardation despite adequate nutritional and metabolic management. Design, setting, participants, & measurements: The study design included randomized, parallel groups in an open, multicenter trial comparing GH (0.33 mg/kg per wk) with nontreatment with GH during 12 months. Sixteen infants who had growth retardation, were aged 12 ± 3 months, had CRF (GFR ≤60 ml/min per 1.73 m2), and had adequate nutritional intake and good metabolic control were recruited from eight pediatric nephrology departments from Spain and Portugal. Main outcome measures were body length, body weight, bone age, biochemical and hormonal analyses, renal function, bone mass, and adverse effects. Results: Length gain in infants who were treated with GH was statistically greater (P < 0.05) than that of nontreated children (14.5 versus 9.5 cm/yr; SD score 1.43 versus −0.11). The GH-induced stimulation of growth was associated with no undesirable effects on bone maturation, renal failure progression, or metabolic control. In addition, GH treatment improved forearm bone mass and increased serum concentrations of total and free IGF-I and IGF-binding protein 3 (IGFBP-3), whereas IGF-II, IGFBP-1, IGFBP-2, GH-binding protein, ghrelin, and leptin were not modified. Conclusions: Infants with CRF and growth retardation despite good metabolic and nutritional control benefit from GH treatment without adverse effects during 12 months of therapy. PMID:20522533

An effective model of DNA like helicoidal structure: with length fluctuation nonlinearity

NASA Astrophysics Data System (ADS)

Tseytlin, Y. M.

2011-03-01

One of the natural helicoidal nanostructure, which thermomechanical features are studied carefully with the help of different mechanical models, is a DNA cell / molecule. Our study proves that the experimentally determined nonlinear fluctuations of the molecular length of DNA can be better understood by modeling the molecule as a helicoidal pretwisted nanostrip sensor with nonlinear function. The calculations presented here are in good agreement with the experimental data within 10%. Other used by many researchers mechanical models such as an elastic rod, wormlike chain (WLC), accordion bellows, or an elastic core wrapped with rigid wires do not show the possible variance nonlinearity of thermomechanical DNA molecular length fluctuations. We have found that the nonlinear variance of the length fluctuations is an intrinsic property of the micro-nano-sensors with helicoidal shape. This model allows us to estimate the persistence length and twist-stretch coupling of a DNA molecule as well. It also shows the molecule's overwinding possibility at initial stretching with correct numerical representation.

From single Debye-Hückel chains to polyelectrolyte solutions: Simulation results

NASA Astrophysics Data System (ADS)

Kremer, Kurt

1996-03-01

This lecture will present results from simulations of single weakly charged flexible chains, where the electrostatic part of the interaction is modeled by a Debye-Hückel potential,( with U. Micka, IFF, Forschungszentrum Jülich, 52425 Jülich, Germany) as well as simulations of polyelectrolyte solutions, where the counterions are explicitly taken into account( with M. J. Stevens, Sandia Nat. Lab., Albuquerque, NM 87185-1111) ( M. J. Stevens, K. Kremer, JCP 103), 1669 (1995). The first set of the simulations is meant to clear a recent contoversy on the dependency of the persistence length LP on the screening length Γ. While the analytic theories give Lp ~ Γ^x with either x=1 or x=2, the simulations find for all experimentally accessible chain lengths a varying exponent, which is significantly smaller than 1. This causes serious doubts on the applicability of this model for weakly charged polyelectrolytes in general. The second part deals with strongly charged flexible polyelectrolytes in salt free solution. These simulations are performed for multichain systems. The full Coulomb interactions of the monomers and counterions are treated explicitly. Experimental measurements of the osmotic pressure and the structure factor are reproduced and extended. The simulations reveal a new picture of the chain structure based on calculations of the structure factor, persistence length, end-to-end distance, etc. Even at very low density, the chains show significant bending. Furthermore, the chains contract significantly before they start to overlap. We also show that counterion condensation dramatically alters the chain structure, even for a good solvent backbone.

Influence of continuous illumination on estrous cycle of rats: time course of changes in levels of gonadotropins and ovarian steroids until occurrence of persistent estrus.

PubMed

Takeo, Y

1984-08-01

Plasma concentrations of LH, FSH, 17 beta-estradiol, estrone and progesterone were determined chronologically by radioimmunoassays in two groups of adult female rats exposed to continuous illumination (LL). Group 1 rats showing vaginal estrous cycles were sacrificed at 3- to 6-hour intervals during late proestrus through early estrus of the first 5 cycles after exposure to LL. Group 2 animals which displayed persistent vaginal estrus in an early period of exposure to LL were killed on the 2nd, 3rd, 4th, 5th and 7th days of vaginal estrus. In Group 1 rats, surges of the hormones, except estrone, took place in all the 5 cycles. The occurrence of peak hormone levels in each cycle was invariably delayed after transfer of animals to LL. According to regression analyses, the lengths of secretion cycles of LH, FSH, 17 beta-estradiol and progesterone in rats under LL were 100.89, 100.46, 101.14 and 101.06 h, respectively. Elevation of 17 beta-estradiol levels was observed prior to the LH surge, and peaks of progesterone and FSH occurred following it. However, the secretion patterns of these hormones appear to be disrupted with length of exposure to LL. In group 2 rats, the mean concentration of LH during persistent estrus was approximately similar to that on the morning of the days of proestrus of the 4-day cycles of rats placed under an alternating 12-hour light-dark regimen (LD), whereas the mean FSH concentration was continuously low. While the concentrations of 17 beta-estradiol and estrone in persistent-estrous rats were elevated, progesterone levels remained low.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemostasis and sealing of air leaks in the lung using high-intensity focused ultrasound.

PubMed

Vaezy, Shahram; Zderic, Vesna; Karmy-Jones, Riyad; Jurkovich, Gregory J; Cornejo, Carol; Martin, Roy W

2007-06-01

Operative management of parenchymal lung injury can be complicated by persistent hemorrhage and air leak, which might require resection. Techniques that preserve parenchyma are associated with improved survival. High-intensity focused ultrasound (HIFU) has been demonstrated as a useful method for hemostasis in experimental solid organ injuries. We wished to investigate whether this could be applied to lung injuries. An intraoperative HIFU device (frequency of 5.7 MHz, acoustic power of 65 W), equipped with a titanium coupler, was used. Incisions (average length of 2.5 cm, and depth of 5 mm) were made in the lungs of 11 pigs, which created both parenchymal hemorrhage and air leakage. In treatment experiments, 70 incisions were sealed with HIFU. The HIFU application started within 10 seconds of inducing the injury. Hemostasis was assessed by visual observation of sealed incisions. The possible air leakage was determined by submersing the sealed incision under the layer of water and observing for air bubble formation. In control experiments, five incisions were left untreated to monitor air leaks and bleeding for 2 minutes. Hemostasis and pneumostasis (sealing of air leaks) of the treated incisions were achieved in 51 +/- 37 seconds (mean +/- SD) (range of 10-210 seconds) of HIFU application time. Over 95% of incisions were hemostatic within 2 minutes of HIFU application. The treatment time was not dependent on the incision length or depth. In control experiments, the air leaking and bleeding were still present at 2 minutes after the injury. Intraoperative HIFU might provide an effective method of hemostasis and control of air leaks from lacerations caused by trauma.

Influence of charge and flexibility on smectic phase formation in filamentous virus suspensions

NASA Astrophysics Data System (ADS)

Purdy, Kirstin R.; Fraden, Seth

2007-07-01

We present experimental measurements of the cholesteric-smectic phase transition of suspensions of charged semiflexible rods as a function of rod flexibility and surface charge. The rod particles consist of the bacteriophage M13 and closely related mutants, which are structurally identical to M13, but vary either in contour length and therefore ratio of persistence length to contour length, or surface charge. Surface charge is altered in two ways; by changing solution pH and by comparing M13 with fd virus, a virus which differs from M13 only by the substitution of a single charged amino acid for a neutral one per viral coat protein. Phase diagrams are measured as a function of particle length, particle charge, and ionic strength. The experimental results are compared with existing theoretical predictions for the phase behavior of flexible rods and charged rods.

Telomeres and telomere dynamics: relevance to cancers of the gastrointestinal tract

PubMed Central

Basu, Nivedita; Skinner, Halcyon G.; Litzelman, Kristin; Vanderboom, Russell; Baichoo, Esha; Boardman, Lisa A.

2013-01-01

Summary Aberrations in telomere length and telomere maintenance contribute to cancer development. In this article, we review basic principles of telomere length in normal and tumor tissue and the presence of the two main telomere maintenance pathways as they pertain to GI tract cancer. Peripheral blood telomeres are shorter in patients with many types of GI tract cancers. Telomere length in tumor DNA also appears to shorten early in cancer development. Tumor telomere shortening is often accompanied by telomerase activation to protect genetically damaged DNA from normal cell senescence or apoptosis, allowing immortalized but damaged DNA to persist. Alternative lengthening of telomeres (ALT) is another mechanism used by cancer to maintain telomere length in cancer cells. Telomerase and ALT activators and inhibitors may become important chemopreventive or chemotherapeutic agents as our understanding of telomere biology, specific telomere related phenotypes, and its relationship to carcinogenesis increases. PMID:24161135

Boosting Photon Harvesting in Organic Solar Cells with Highly Oriented Molecular Crystals via Graphene-Organic Heterointerface.

PubMed

Jo, Sae Byeok; Kim, Hyun Ho; Lee, Hansol; Kang, Boseok; Lee, Seongkyu; Sim, Myungsun; Kim, Min; Lee, Wi Hyoung; Cho, Kilwon

2015-08-25

Photon harvesting in organic solar cells is highly dependent on the anisotropic nature of the optoelectronic properties of photoactive materials. Here, we demonstrate an efficient approach to dramatically enhance photon harvesting in planar heterojunction solar cells by using a graphene-organic heterointerface. A large area, residue-free monolayer graphene is inserted at anode interface to serve as an atomically thin epitaxial template for growing highly orientated pentacene crystals with lying-down orientation. This anisotropic orientation enhances the overall optoelectronic properties, including light absorption, charge carrier lifetime, interfacial energetics, and especially the exciton diffusion length. Spectroscopic and crystallographic analysis reveal that the lying-down orientation persists until a thickness of 110 nm, which, along with increased exciton diffusion length up to nearly 100 nm, allows the device optimum thickness to be doubled to yield significantly enhanced light absorption within the photoactive layers. The resultant photovoltaic performance shows simultaneous increment in Voc, Jsc, and FF, and consequently a 5 times increment in the maximum power conversion efficiency than the equivalent devices without a graphene layer. The present findings indicate that controlling organic-graphene heterointerface could provide a design strategy of organic solar cell architecture for boosting photon harvesting.

The influence of depression on personality traits in patients with fibromyalgia: a case-control study.

PubMed

Santos, Daniela M; Lage, Laís V; Jabur, Eleonora K; Kaziyama, Helena H S; Iosifescu, Dan V; De Lucia, Mara Cristina S; Fráguas, Renério

2017-01-01

We developed this study to investigate the association of fibromyalgia with personality traits, controlling for depression and other potential confounders. We assessed personality traits using the Cloninger's Temperament and Character Inventory (TCI) in 78 female patients with fibromyalgia and in a control group of 78 subjects without fibromyalgia. The Mini-International Neuropsychiatric Interview was used to assess depression and anxiety diagnoses. To investigate the association between fibromyalgia and the Cloninger's Temperament and Character Inventory we performed unadjusted and adjusted analyses of covariance, using the TCI score as dependent variable and adjusting the model for depression, anxiety and for clinical and socio-demographic variables. We used a backward selection method to choose the final model. In the unadjusted analysis, fibromyalgia was associated with all personality traits, except persistency. After adjusting for depression and anxiety, patients with fibromyalgia presented decreased novelty seeking compared to controls; the differences in other personality traits were no longer significant. Novelty seeking was also correlated with the length of history of fibromyalgia and pain intensity. Decreased novelty seeking may be a personality trait associated with fibromyalgia. Depression and anxiety should be considered potential confounders in the evaluation of personality traits in this population.

The relationship between second-to-fourth digit ratio and female gender identity.

PubMed

Hisasue, Shin-Ichi; Sasaki, Shoko; Tsukamoto, Taiji; Horie, Shigeo

2012-11-01

Gender identity and the second-to-fourth finger length ratio (2D : 4D) are discriminative between the sexes. However, the relationship between 2D : 4D and gender identity disorder (GID) is still controversial. The aim of this study is to investigate the relationship between 2D : 4D and score on the Gender Identity Scale (GIS) in female-to-male (FtM) GID subjects. Thirty-seven GID-FtM with testosterone replacement therapy from our clinic were included in this study. As controls, 20 male and 20 female volunteers participated from our institution (medical doctors and nurses). We photocopied left and right hands of the participants and measured the second and fourth finger lengths. Gender identity was measured with the GIS. 2D : 4D digit ratio and GIS in male, female, and GID-FtM subjects. The 2D : 4D (mean ± standard deviation) in male, female, and GID-FtM were 0.945 ± 0.029, 0.999 ± 0.035, and 0.955 ± 0.029 in right hand and 0.941 ± 0.024, 0.979 ± 0.040, and 0.954 ± 0.036 in left hand, respectively. The 2D : 4D was significantly lower in male controls in both hands and GID-FtM in the right hand than in female controls (P < 0.05, analysis of variance). Multiple linear regression analysis revealed that "consistent gender identity" score in the higher domain in GIS and "persistent gender identity" score in the lower domain are statistically significant variables correlating with 2D : 4D in the right hands among biological females. The finger length ratio 2D : 4D in GID-FtM was significantly lower than in female controls in the right hand in this study. 2D : 4D showed a positive correlation with GIS score. Because 2D : 4D influences are assumed to be established in early life and to reflect testosterone exposure, our results suggest a relationship between GID-FtM and perinatal testosterone. © 2012 International Society for Sexual Medicine.

Catheter ablation in patients with persistent atrial fibrillation

PubMed Central

Kirchhof, Paulus; Calkins, Hugh

2017-01-01

Catheter ablation is increasingly offered to patients who suffer from symptoms due to atrial fibrillation (AF), based on a growing body of evidence illustrating its efficacy compared with antiarrhythmic drug therapy. Approximately one-third of AF ablation procedures are currently performed in patients with persistent or long-standing persistent AF. Here, we review the available information to guide catheter ablation in these more chronic forms of AF. We identify the following principles: Our clinical ability to discriminate paroxysmal and persistent AF is limited. Pulmonary vein isolation is a reasonable and effective first approach for catheter ablation of persistent AF. Other ablation strategies are being developed and need to be properly evaluated in controlled, multicentre trials. Treatment of concomitant conditions promoting recurrent AF by life style interventions and medical therapy should be a routine adjunct to catheter ablation of persistent AF. Early rhythm control therapy has a biological rationale and trials evaluating its value are underway. There is a clear need to generate more evidence for the best approach to ablation of persistent AF beyond pulmonary vein isolation in the form of adequately powered controlled multi-centre trials. PMID:27389907

Soil-based systemic delivery and phyllosphere in vivo propagation of bacteriophages: Two possible strategies for improving bacteriophage persistence for plant disease control.

PubMed

Iriarte, Fanny B; Obradović, Aleksa; Wernsing, Mine H; Jackson, Lee E; Balogh, Botond; Hong, Jason A; Momol, M Timur; Jones, Jeffrey B; Vallad, Gary E

2012-10-01

Soil-based root applications and attenuated bacterial strains were evaluated as means to enhance bacteriophage persistence on plants for bacterial disease control. In addition, the systemic nature of phage applied to tomato roots was also evaluated. Several experiments were conducted applying either single phages or phage mixtures specific for Ralstonia solanacearum , Xanthomonas perforans or X. euvesicatoria to soil surrounding tomato plants and measuring the persistence and translocation of the phages over time. In general, all phages persisted in the roots of treated plants and were detected in stems and leaves; although phage level varied and persistence in stems and leaves was at a much lower level compared with persistence in roots. Bacterial wilt control was typically best if the phage or phage mixtures were applied to the soil surrounding tomatoes at the time of inoculation, less effective if applied 3 days before inoculation, and ineffective if applied 3 days after inoculation. The use of an attenuated X. perforans strain was also evaluated to improve the persistence of phage populations on tomato leaf surfaces. In greenhouse and field experiments, foliar applications of an attenuated mutant X. perforans 91-118:∆ OPGH strain prior to phage applications significantly improved phage persistence on tomato foliage compared with untreated tomato foliage. Both the soil-based bacteriophage delivery and the use of attenuated bacterial strains improved bacteriophage persistence on respective root and foliar tissues, with evidence of translocation with soil-based bacteriophage applications. Both strategies could lead to improved control of bacterial pathogens on plants.

Human mammary epithelial cells exhibit a bimodal correlated random walk pattern.

PubMed

Potdar, Alka A; Jeon, Junhwan; Weaver, Alissa M; Quaranta, Vito; Cummings, Peter T

2010-03-10

Organisms, at scales ranging from unicellular to mammals, have been known to exhibit foraging behavior described by random walks whose segments confirm to Lévy or exponential distributions. For the first time, we present evidence that single cells (mammary epithelial cells) that exist in multi-cellular organisms (humans) follow a bimodal correlated random walk (BCRW). Cellular tracks of MCF-10A pBabe, neuN and neuT random migration on 2-D plastic substrates, analyzed using bimodal analysis, were found to reveal the BCRW pattern. We find two types of exponentially distributed correlated flights (corresponding to what we refer to as the directional and re-orientation phases) each having its own correlation between move step-lengths within flights. The exponential distribution of flight lengths was confirmed using different analysis methods (logarithmic binning with normalization, survival frequency plots and maximum likelihood estimation). Because of the presence of non-uniform turn angle distribution of move step-lengths within a flight and two different types of flights, we propose that the epithelial random walk is a BCRW comprising of two alternating modes with varying degree of correlations, rather than a simple persistent random walk. A BCRW model rather than a simple persistent random walk correctly matches the super-diffusivity in the cell migration paths as indicated by simulations based on the BCRW model.

New drug candidates and therapeutic targets for tuberculosis therapy.

PubMed

Zhang, Ying; Post-Martens, Katrin; Denkin, Steven

2006-01-01

Despite advances in chemotherapy and the BCG (Bacillus Calmette-Guérin) vaccine, tuberculosis remains a significant infectious disease. Although it can be cured, the therapy takes at least 6-9 months, and the laborious and lengthy treatment brings with it dangers of noncompliance, significant toxicity and drug resistance. The increasing emergence of drug resistance and the problem of mycobacterial persistence highlight the need to develop novel TB drugs that are active against drug resistant bacteria but, more importantly, kill persistent bacteria and shorten the length of treatment. Recent new and exciting developments in tuberculosis drug discovery show good promise of a possible revolution in the chemotherapy of tuberculosis.

Glatiramer acetate treatment persistence - but not adherence - in multiple sclerosis patients is predicted by health-related quality of life and self-efficacy: a prospective web-based patient-centred study (CAIR study).

PubMed

Jongen, Peter Joseph; Lemmens, Wim A; Hoogervorst, Erwin L; Donders, Rogier

2017-03-14

In patients with relapsing remitting multiple sclerosis (RRMS) the persistence of and adherence to disease modifying drug (DMD) treatment is inadequate. To take individualised measures there is a need to identify patients with a high risk of non-persistence or non-adherence. As patient-related factors have a major influence on persistence and adherence, we investigated whether health-related quality of life (HRQoL) and self-efficacy could predict persistence or adherence. In a prospective web-based patient-centred study in 203 RRMS patients, starting treatment with glatiramer acatete (GA) 20 mg subcutaneously daily, we measured physical and mental HRQoL (Multiple Sclerosis Quality of Life-54 questionnaire), functional and control self-efficacy (Multiple Sclerosis Self-Efficacy Scale), the 12-month persistence rate and, in persistent patients, the percentage of missed doses. HRQoL and self-efficacy were compared between persistent and non-persistent patients, and between adherent and non-adherent patients. Logistic regression analysis was used to assess whether persistence and adherence were explained by HRQoL and self-efficacy. Persistent patients had higher baseline physical (mean 58.1 [standard deviation, SD] 16.9) and mental HRQoL (63.8 [16.8]) than non-persistent patients (49.5 [17.6]; 55.9 [20.4]) (P = 0.001; P = 0.003) with no differences between adherent and non-adherent patients (P = 0.46; P = 0.54). Likewise, in persistent patients function (752 [156]) and control self-efficacy (568 [178]) were higher than in non-persistent patients (689 [173]; 491 [192]) (P = 0.009; P = 0.004), but not in adherent vs. non-adherent patients (P = 0.26; P = 0.82). Logistic regression modelling identified physical HRQoL and control self-efficacy as factors that explained persistence. Based on predicted scores from the model, patients were classified into quartiles and the percentage of non-persistent patients per quartile was calculated: non-persistence in the highest quartile was 23.4 vs. 53.2% in the lowest quartile. Risk differentiation with respect to adherence was not possible. Based on these findings we propose a practical work-up scheme to identify patients with a high risk of non-persistence and to identify persistence-related factors. Findings suggest that pre-treatment physical HRQoL and control self-efficacy may identify RRMS patients with a high risk of early discontinuation of injectable DMD treatment. Targeting of high-risk patients may enable the efficient use of persistence-promoting measures. Nederlands Trial Register code: NTR2432 .

Anxiety in speakers who persist and recover from stuttering.

PubMed

Davis, Stephen; Shisca, Daniella; Howell, Peter

2007-01-01

The study was designed to see whether young children and adolescents who persist in their stutter (N=18) show differences in trait and/or state anxiety compared with people who recover from their stutter (N=17) and fluent control speakers (N=19). A fluent control group, a group of speakers who have been documented as stuttering in the past but do not stutter now and a group of speakers (also with a documented history of stuttering) who persist in their stuttering participated, all aged 10-17 years. The State-Trait Anxiety Inventory for Children was administered. There were no differences between persistent, recovered and control groups with regard to trait anxiety. The persistent group had higher state anxiety than controls and the recovered group for three out of four speaking situations. The findings are interpreted as showing that anxiety levels in certain affective states appear to be associated with the speaking problem. A reader should be able to appreciate the difference between state and trait anxiety understand views about how the role anxiety has on stuttering has changed over time appreciate different views about how anxiety affects speakers who persist and recover from stuttering see why longitudinal work is needed to study these issues.

Efffect of Aeroallergen Sensitization on Asthma Control in African-American Teens with Persistent Asthma

EPA Science Inventory

In African-American adolescents with persistent asthma, allergic profile predicted the likelihood of having poorly controlled asthma despite guidelines-directed therapies. Our results suggest that tree and weed pollen sensitization are independent risk factors for poorly controll...

Understanding Confounding Effects in Linguistic Coordination: An Information-Theoretic Approach

PubMed Central

Gao, Shuyang; Ver Steeg, Greg; Galstyan, Aram

2015-01-01

We suggest an information-theoretic approach for measuring stylistic coordination in dialogues. The proposed measure has a simple predictive interpretation and can account for various confounding factors through proper conditioning. We revisit some of the previous studies that reported strong signatures of stylistic accommodation, and find that a significant part of the observed coordination can be attributed to a simple confounding effect—length coordination. Specifically, longer utterances tend to be followed by longer responses, which gives rise to spurious correlations in the other stylistic features. We propose a test to distinguish correlations in length due to contextual factors (topic of conversation, user verbosity, etc.) and turn-by-turn coordination. We also suggest a test to identify whether stylistic coordination persists even after accounting for length coordination and contextual factors. PMID:26115446

The influence of birth size on intelligence in healthy children.

PubMed

Broekman, Birit F P; Chan, Yiong-Huak; Chong, Yap-Seng; Quek, Swee-Chye; Fung, Daniel; Low, Yen-Ling; Ooi, Yoon-Phaik; Gluckman, Peter D; Meaney, Michael J; Wong, Tien-Yin; Saw, Seang-Mei

2009-06-01

Birth parameters have been hypothesized to have an influence on IQ. However, studies within the range of normal birth size have been sparse. With this study we examined the associations between birth length, birth weight, head circumference, and gestational age within the normal birth size range in relation to childhood IQ in Asian children. A cohort of 1979 of 2913 Asian children aged 7 to 9 years, recruited from 3 schools in Singapore, were followed yearly from 1999 onward. Birth parameters were recorded by health personnel. Childhood IQ was measured with the Raven's Standard Progressive Matrices at ages 8 to 12. The mean IQ score across the sample (n = 1645) was 114.2. After controlling for multiple confounders for every 1-cm increment in birth length, 1 kg in birth weight, or 1 cm in head circumference, there was a corresponding increase in IQ of 0.49 points (P for trend < .001), 2.19 points (P for trend = .007) and .62 points (P for trend = .003), respectively. These associations persisted even after exclusion of premature children and children with extreme weights and head circumferences. Longer birth length, higher birth weight, or larger head circumferences within the normal birth size range are associated with higher IQ scores in Asian children. Our results suggest that antenatal factors reflected in altered rates of growth but within the normative range of pregnancy experiences play a role in generating cognitive potential. This has implications for targeting early intervention and preventative programs.

Catheter ablation versus medical therapy for patients with persistent atrial fibrillation: a systematic review and meta-analysis of evidence from randomized controlled trials.

PubMed

Chen, Chen; Zhou, Xinbin; Zhu, Min; Chen, Shenjie; Chen, Jie; Cai, Hongwen; Dai, Jin; Xu, Xiaoming; Mao, Wei

2018-06-01

The superiority of catheter ablation (CA) for persistent (and long-standing persistent) atrial fibrillation (AF) is currently not well defined. We performed a meta-analysis of randomized controlled trials (RCTs) to assess the clinical outcomes of CA compared with medical therapy in persistent AF patients. We systematically searched PubMed, EMBASE, the Cochrane Library, and clinicaltrials.gov for RCTs comparing CA with medical therapy in patients with persistent AF. For CA vs medical rhythm control, the primary outcome was freedom from atrial arrhythmia. For CA vs medical rate control, the primary outcome was the change in the left ventricular ejection fraction (LVEF). Eight studies with a total of 809 patients were included in the final analysis. Compared with medical rhythm control, CA was superior in achieving freedom from atrial arrhythmia (RR 2.08, 95% CI [1.67, 2.58]; P < 0.00001). Similar result was found in CA arm without antiarrhythmic drug use after operation (RR 1.82, 95%CI [1.33, 2.49]; P = 0.0002). CA was also superior in reducing the probability of cardioversion (RR 0.59, 95%CI [0.46, 0.76]; P < 0.0001) and hospitalization (RR 0.54, 95%CI [0.39, 0.74]; P = 0.0002). Compared with the medical rate control in persistent AF patients with heart failure (HF), CA significantly improved the LVEF (MD 7.72, 95%CI [4.78, 10.67]; P < 0.00001) and reduced Minnesota Living with Heart Failure Questionnaire scores (MD 11.1395% CI [2.52-19.75]; P = 0.01). CA appeared to be superior to medical therapy in persistent AF patients and might be considered as a first-line therapy for some persistent AF patients especially for those with HF.

Persistent atrial fibrillation vs paroxysmal atrial fibrillation: differences in management.

PubMed

Margulescu, Andrei D; Mont, Lluis

2017-08-01

Atrial fibrillation (AF) is the most common human arrhythmia. AF is a progressive disease, initially being nonsustained and induced by trigger activity, and progressing towards persistent AF through alteration of the atrial myocardial substrate. Treatment of AF aims to decrease the risk of stroke and improve the quality of life, by preventing recurrences (rhythm control) or controlling the heart rate during AF (rate control). In the last 20 years, catheter-based and, less frequently, surgical and hybrid ablation techniques have proven more successful compared with drug therapy in achieving rhythm control in patients with AF. However, the efficiency of ablation techniques varies greatly, being highest in paroxysmal and lowest in long-term persistent AF. Areas covered: In this review, we discuss the fundamental differences between paroxysmal and persistent AF and the potential impact of those differences on patient management, emphasizing the available therapeutic strategies to achieve rhythm control. Expert commentary: Treatment to prevent AF recurrences is suboptimal, particularly in patients with persistent AF. Emerging technologies, such as documentation of atrial fibrosis using magnetic resonance imaging and documentation of electrical substrate using advanced electrocardiographic imaging techniques are likely to provide valuable insights about patient-specific tailoring of treatments.

How much a galaxy knows about its large-scale environment?: An information theoretic perspective

NASA Astrophysics Data System (ADS)

Pandey, Biswajit; Sarkar, Suman

2017-05-01

The small-scale environment characterized by the local density is known to play a crucial role in deciding the galaxy properties but the role of large-scale environment on galaxy formation and evolution still remain a less clear issue. We propose an information theoretic framework to investigate the influence of large-scale environment on galaxy properties and apply it to the data from the Galaxy Zoo project that provides the visual morphological classifications of ˜1 million galaxies from the Sloan Digital Sky Survey. We find a non-zero mutual information between morphology and environment that decreases with increasing length-scales but persists throughout the entire length-scales probed. We estimate the conditional mutual information and the interaction information between morphology and environment by conditioning the environment on different length-scales and find a synergic interaction between them that operates up to at least a length-scales of ˜30 h-1 Mpc. Our analysis indicates that these interactions largely arise due to the mutual information shared between the environments on different length-scales.

Remodeling of sinus node function after catheter ablation of right atrial flutter.

PubMed

Daoud, Emile G; Weiss, Raul; Augostini, Ralph S; Kalbfleisch, Steven J; Schroeder, Jason; Polsinelli, Georgia; Hummel, John D

2002-01-01

The purpose of this study was to investigate the effect of ablation of right atrial flutter upon sinus node function in humans. This study enrolled 35 patients. Twenty-four patients (16 men and 8 women; age 68 +/- 11 years) were referred for ablation of persistent atrial flutter (duration 8 +/- 11 months). After ablation, there was abnormal sinus node function defined as a corrected sinus node recovery time (CSNRT) > or = 550 msec. The control group consisted of 11 patients who were undergoing pacemaker implantation for sinus node disease but did not have a history of atrial dysrhythmias or ablation. Within 24 hours of ablation or pacemaker implantation, baseline maximal CSNRT was measured through a permanent pacemaker by AAI pacing at six cycle lengths: 600, 550, 500, 450, 400, and 350 msec. CSNRT then was measured in the same manner at 48 hours, 14 days, and 3 months after ablation/pacemaker implantation. P wave amplitude and duration, and percent atrial sensing also were assessed at the same intervals. For patients undergoing atrial flutter ablation, there was progressive temporal recovery of CSNRT (1,204 +/- 671 msec at baseline vs 834 +/- 380 msec at 3 months; P < 0.001) and a significant increase in the percent atrial sensing and P wave amplitude at 3 months compared with baseline (P < 0.001). In control subjects, there was no change in the CSNRT, percent atrial pacing, or P wave amplitude. After ablation of persistent atrial flutter, there is temporal recovery of CSNRT and increase in spontaneous atrial activity. These findings suggest that atrial flutter induces reversible changes in sinus node function.

Control of arc length during gas metal arc welding

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

Madigan, R.B.; Quinn, T.P.

1994-12-31

An arc-length control system has been developed for gas metal arc welding (GMAW) under spray transfer welding conditions. The ability to monitor and control arc length during arc welding allows consistent weld characteristics to be maintained and therefore improves weld quality. Arc length control has only been implemented for gas tungsten arc welding (GTAW), where an automatic voltage control (AVC) unit adjusts torch-to-work distance. The system developed here compliments the voltage- and current-sensing techniques commonly used for control of GMAW. The system consists of an arc light intensity sensor (photodiode), a Hall-effect current sensor, a personal computer and software implementingmore » a data interpretation and control algorithms. Arc length was measured using both arc light and arc current signals. Welding current was adjusted to maintain constant arc length. A proportional-integral-derivative (PID) controller was used. Gains were automatically selected based on the desired welding conditions. In performance evaluation welds, arc length varied from 2.5 to 6.5 mm while welding up a sloped workpiece (ramp in CTWD) without the control. Arc length was maintained within 1 mm of the desired (5 mm ) with the control.« less

The influence of divided attention on walking turns: Effects on gait control in young adults with and without a history of low back pain.

PubMed

Smith, Jo Armour; Gordon, James; Kulig, Kornelia

2017-10-01

The cognitive control of gait is altered in individuals with low back pain, but it is unclear if this alteration persists between painful episodes. Locomotor perturbations such as walking turns may provide a sensitive measure of gait adaptation during divided attention in young adults. The purpose of this study was to investigate changes in gait during turns performed with divided attention, and to compare healthy young adults with asymptomatic individuals who have a history of recurrent low back pain (rLBP). Twenty-eight participants performed 90° ipsilateral walking turns at a controlled speed of 1.5m/s. During the divided attention condition they concurrently performed a verbal 2-back task. Step length and width, trunk-pelvis and hip excursion, inter-segmental coordination and stride-to-stride variability were quantified using motion capture. Mixed-model ANOVA were used to examine the effect of divided attention and group, and interaction effects on the selected variables. Step length variability decreased significantly with divided attention in the healthy group but not in the rLBP group (post-hoc p=0.024). Inter-segmental coordination variability was significantly decreased during divided attention (main effect of condition p <0.000). There were small but significant reductions in hip axial and sagittal motion across groups (main effect of condition p=0.044 and p=0.040 respectively), and a trend toward increased frontal motion in the rLBP group only (post-hoc p=0.048). These findings suggest that the ability to switch attentional resources during gait is altered in young adults with a history of rLBP, even between symptomatic episodes. Copyright © 2017 Elsevier B.V. All rights reserved.

Characteristics of the Unexpected Message Queue of MPI applications

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

Keller, Rainer; Graham, Richard L

2010-01-01

High Performance Computing systems are used on a regular basis to run a myriad of application codes, yet a surprising dearth of information exists with respect to communications characteristics. Even less information is available on the low-level communication libraries, such as the length of MPI Unexpected Message Queues (UMQs) and the length of time such messages spend in these queues. Such information is vital to developing appropriate strategies for handling such data at the library and system level. In this paper we present data on the communication characteristics of three applications GTC, LSMS, and S3D. We present data on themore » size of their UMQ, the time spend searching the UMQ and the length of time such messages spend in these queues. We find that for the particular inputs used, these applications have widely varying characteristics with regard to UMQ length and show patterns for specific applications which persist over various scales.« less

Lesion progression in post-treatment persistent endodontic lesions.

PubMed

Yu, Victoria Soo Hoon; Messer, Harold Henry; Shen, Liang; Yee, Robert; Hsu, Chin-ying Stephen

2012-10-01

Radiographic lesions related to root-filled teeth may persist for long periods after treatment and are considered to indicate failure of initial treatment. Persistent lesions are found in a proportion of cases, but information on lesion progression is lacking. This study examined the incidence of lesion improvement, remaining unchanged, and deterioration among persistent lesions in a group of patients recruited from a university-based clinic and identified potential predictors for lesion progression. Patients of a university clinic with persistent endodontic lesions at least 4 years since treatment and with original treatment radiographs available were recruited with informed consent. Data were obtained by interview and from dental records and clinical and radiographic examinations. Univariate and multivariate statistical analyses were carried out by using SPSS (version 19). One hundred fifty-one persistent lesions were identified in 114 patients. A majority of the lesions (107, 70.9%) received treatment between 4 and 5 years prior. Eighty-six lesions (57.0%) improved, 18 (11.9%) remained unchanged, and 47 (31.1%) deteriorated since treatment. Potential predictors for lesions that did not improve included recall lesion size, pain on biting at recall examination, history of a postobturation flare-up, and a non-ideal root-filling length (P < .05). Lesions that had persisted for a longer period appeared less likely to be improving (relative risk, 1.038; 95% confidence interval, 1.000-1.077). A specific time interval alone should not be used to conclude that a lesion will not resolve without intervention. This study identified several clinical factors that are associated with deteriorating persistent lesions, which should aid in identifying lesions that require further intervention. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Simultaneous Biatrial High-Density (510-512 Electrodes) Epicardial Mapping of Persistent and Long-Standing Persistent Atrial Fibrillation in Patients: New Insights Into the Mechanism of Its Maintenance.

PubMed

Lee, Seungyup; Sahadevan, Jayakumar; Khrestian, Celeen M; Cakulev, Ivan; Markowitz, Alan; Waldo, Albert L

2015-12-01

The mechanism(s) of persistent and long-standing persistent (LSP) atrial fibrillation (AF) is/are poorly understood. We performed high-density, simultaneous, biatrial, epicardial mapping of persistent and LSP AF in patients undergoing open heart surgery (1) to test the hypothesis that persistent and LSP AF are due to ≥ 1 drivers, either focal or reentrant, and (2) to characterize associated atrial activation. Twelve patients with persistent and LSP AF (1 month to 9 years duration) were studied at open heart surgery. During AF, electrograms were recorded from both atria simultaneously for 1 to 5 minutes from 510 to 512 epicardial electrodes with ECG lead II. Thirty-two consecutive seconds of activation sequence maps were produced per patient. During AF, multiple foci (QS unipolar atrial electrograms) of different cycle lengths (mean, 175 ± 18 ms) were present in both atria in 11 of 12 patients. Foci (2-4 per patient, duration 5-32 s) were either sustained or intermittent, were predominantly found in the lateral left atrial free wall, and likely acted as drivers. Random and nonrandom breakthrough activation sites (initial r or R in unipolar atrial electrograms) were also found. In 1 of 12 patients, only breakthrough sites were found. All wave fronts emanated from foci and breakthrough sites, and largely either collided or merged with each other at variable sites. Repetitive focal QS activation occasionally generated repetitive wannabe reentrant activation in 5 of 12 patients. No actual reentry was found. During persistent and LSP AF in 12 patients, wave fronts emanating from foci and breakthrough sites maintained AF. No reentry was demonstrated. © 2015 American Heart Association, Inc.

Persistence of canine distemper virus in the Greater Yellowstone ecosystem's carnivore community.

PubMed

Almberg, Emily S; Cross, Paul C; Smith, Douglas W

2010-10-01

Canine distemper virus (CDV) is an acute, highly immunizing pathogen that should require high densities and large populations of hosts for long-term persistence, yet CDV persists among terrestrial carnivores with small, patchily distributed groups. We used CDV in the Greater Yellowstone ecosystem's (GYE) wolves (Canis lupus) and coyotes (Canis latrans) as a case study for exploring how metapopulation structure, host demographics, and multi-host transmission affect the critical community size and spatial scale required for CDV persistence. We illustrate how host spatial connectivity and demographic turnover interact to affect both local epidemic dynamics, such as the length and variation in inter-epidemic periods, and pathogen persistence using stochastic, spatially explicit susceptible-exposed-infectious-recovered simulation models. Given the apparent absence of other known persistence mechanisms (e.g., a carrier or environmental state, densely populated host, chronic infection, or a vector), we suggest that CDV requires either large spatial scales or multi-host transmission for persistence. Current GYE wolf populations are probably too small to support endemic CDV. Coyotes are a plausible reservoir host, but CDV would still require 50000-100000 individuals for moderate persistence (> 50% over 10 years), which would equate to an area of 1-3 times the size of the GYE (60000-200000 km2). Coyotes, and carnivores in general, are not uniformly distributed; therefore, this is probably a gross underestimate of the spatial scale of CDV persistence. However, the presence of a second competent host species can greatly increase the probability of long-term CDV persistence at much smaller spatial scales. Although no management of CDV is currently recommended for the GYE, wolf managers in the region should expect periodic but unpredictable CDV-related population declines as often as every 2-5 years. Awareness and monitoring of such outbreaks will allow corresponding adjustments in management activities such as regulated public harvest, creating a smooth transition to state wolf management and conservation after > 30 years of being protected by the Endangered Species Act.

The risk for persistent adult alcohol and nicotine dependence: the role of childhood maltreatment.

PubMed

Elliott, Jennifer C; Stohl, Malka; Wall, Melanie M; Keyes, Katherine M; Goodwin, Renee D; Skodol, Andrew E; Krueger, Robert F; Grant, Bridget F; Hasin, Deborah S

2014-05-01

Alcohol and nicotine dependence are associated with considerable morbidity and mortality, especially when cases are persistent. The risk for alcohol and nicotine dependence is increased by childhood maltreatment. However, the influence of childhood maltreatment on dependence course is unknown, and is evaluated in the current study. Physical, sexual and emotional abuse, and physical and emotional neglect, were evaluated as predictors of persistent alcohol and nicotine dependence over 3 years of follow-up, with and without control for other childhood adversities. National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). NESARC participants completing baseline and follow-up who met criteria at baseline for past-year alcohol dependence (n = 1172) and nicotine dependence (n = 4017). Alcohol Use Disorder and Associated Disabilities Interview Schedule (AUDADIS) measures of alcohol/nicotine dependence, childhood maltreatment and other adverse childhood experiences (e.g. parental divorce). Controlling for demographics only, physical, sexual and emotional abuse and physical neglect predicted 3-year persistence of alcohol dependence [adjusted odds ratio (AOR) = 1.50-2.99; 95% CI = 1.04-4.68] and nicotine dependence (AOR = 1.37-1.74; 95% CI = 1.13-2.11). With other childhood adversities also controlled, maltreatment types remained predictive for alcohol persistence (AOR = 1.53-3.02; 95% CI = 1.07-4.71) and nicotine persistence (AOR = 1.35-1.72; 95% CI = 1.11-2.09). Further, a greater number of maltreatment types incrementally influenced persistence risk (AOR = 1.19-1.36; 95% CI = 1.11-1.56). A history of childhood maltreatment predicts persistent adult alcohol and nicotine dependence. This association, robust to control for other childhood adversities, suggests that maltreatment (rather than a generally difficult childhood) affects the course of dependence. © 2014 Society for the Study of Addiction.

Virtual reality gaming in the rehabilitation of the upper extremities post-stroke.

PubMed

Yates, Michael; Kelemen, Arpad; Sik Lanyi, Cecilia

2016-01-01

Occurrences of strokes often result in unilateral upper limb dysfunction. Dysfunctions of this nature frequently persist and can present chronic limitations to activities of daily living. Research into applying virtual reality gaming systems to provide rehabilitation therapy have seen resurgence. Themes explored in stroke rehab for paretic limbs are action observation and imitation, versatility, intensity and repetition and preservation of gains. Fifteen articles were ultimately selected for review. The purpose of this literature review is to compare the various virtual reality gaming modalities in the current literature and ascertain their efficacy. The literature supports the use of virtual reality gaming rehab therapy as equivalent to traditional therapies or as successful augmentation to those therapies. While some degree of rigor was displayed in the literature, small sample sizes, variation in study lengths and therapy durations and unequal controls reduce generalizability and comparability. Future studies should incorporate larger sample sizes and post-intervention follow-up measures.

Low-temperature plasma-deposited silicon epitaxial films: Growth and properties

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

Demaurex, Bénédicte, E-mail: benedicte.demaurex@epfl.ch; Bartlome, Richard; Seif, Johannes P.

2014-08-07

Low-temperature (≤200 °C) epitaxial growth yields precise thickness, doping, and thermal-budget control, which enables advanced-design semiconductor devices. In this paper, we use plasma-enhanced chemical vapor deposition to grow homo-epitaxial layers and study the different growth modes on crystalline silicon substrates. In particular, we determine the conditions leading to epitaxial growth in light of a model that depends only on the silane concentration in the plasma and the mean free path length of surface adatoms. For such growth, we show that the presence of a persistent defective interface layer between the crystalline silicon substrate and the epitaxial layer stems not only frommore » the growth conditions but also from unintentional contamination of the reactor. Based on our findings, we determine the plasma conditions to grow high-quality bulk epitaxial films and propose a two-step growth process to obtain device-grade material.« less

Dynamical patterns in nematic active matter on a sphere

NASA Astrophysics Data System (ADS)

Henkes, Silke; Marchetti, M. Cristina; Sknepnek, Rastko

2018-04-01

Using simulations of self-propelled agents with short-range repulsion and nematic alignment, we explore the dynamical phases of a dense active nematic confined to the surface of a sphere. We map the nonequilibrium phase diagram as a function of curvature, alignment strength, and activity. Our model reproduces several phases seen in recent experiments on active microtubule bundles confined the surfaces of vesicles. At low driving, we recover the equilibrium nematic ground state with four +1 /2 defects. As the driving is increased, geodesic forces drive the transition to a polar band wrapping around an equator, with large empty spherical caps corresponding to two +1 defects at the poles. Upon further increasing activity, the bands fold onto themselves, and the system eventually transitions to a turbulent state marked by the proliferation of pairs of topological defects. We highlight the key role of the nematic persistence length in controlling pattern formation in these confined systems with positive Gaussian curvature.

Low-temperature plasma-deposited silicon epitaxial films: Growth and properties

DOE PAGES

Demaurex, Bénédicte; Bartlome, Richard; Seif, Johannes P.; ...

2014-08-05

Low-temperature (≤ 180 °C) epitaxial growth yields precise thickness, doping, and thermal-budget control, which enables advanced-design semiconductor devices. In this paper, we use plasma-ehanced chemical vapor deposition to grow homo-epitaxial layers and study the different growth modes on crystalline silicon substrates. In particular, we determine the conditions leading to epitaxial growth in light of a model that depends only on the silane concentration in the plasma and the mean free path length of surface adatoms. For such growth, we show that the presence of a persistent defective interface layer between the crystalline silicon substrate and the epitaxial layer stems notmore » only from the growth conditions but also from unintentional contamination of the reactor. As a result of our findings, we determine the plasma conditions to grow high-quality bulk epitaxial films and propose a two-step growth process to obtain device-grade material.« less

Dynamics of Active Microfilaments

NASA Astrophysics Data System (ADS)

Ling, Feng; Guo, Hanliang; Kanso, Eva

2017-11-01

Soft elastic filaments are ubiquitous in natural and artificial systems at various length scales, and their interactions within and between filaments and their environments provide a persistent source of curiosity due to both the complexity of their behaviors and the relative mathematical simplicity of their structures. Specifically, a deeper understanding of the dynamic characteristics of microscopic filaments in viscous fluids is relevant to many biophysical and physiological processes. Here we start with the Cosserat model that allows all six possible modes of deformation for an elastic rod, and focus on the case of inextensible filaments submerged in viscous fluids by ignoring inertial effects and using local resistive force theory for fluid-filament interactions. We verify our simulations against special analytic solutions and present some results on the active internal control of cilia and flagella motion. We conclude by commenting on the utility of this general framework for studying other cellular and sub-cellular physical processes such as systems involving protein filaments.

Electronic spin transport in gate-tunable black phosphorus spin valves

NASA Astrophysics Data System (ADS)

Liu, Jiawei; Avsar, Ahmet; Tan, Jun You; Oezyilmaz, Barbaros

High charge mobility, the electric field effect and small spin-orbit coupling make semiconducting black phosphorus (BP) a promising material for spintronics device applications requiring long spin distance spin communication with all rectification and amplification actions. Towards this, we study the all electrical spin injection, transport and detection under non-local spin valve geometry in fully encapsulated ultra-thin BP devices. We observe spin relaxation times as high as 4 ns, with spin relaxation lengths exceeding 6 μm. These values are an order of magnitude higher than what have been measured in typical graphene spin valve devices. Moreover, the spin transport depends strongly on charge carrier concentration and can be manipulated in a spin transistor-like manner by controlling electric field. This behaviour persists even at room temperature. Finally, we will show that similar to its electrical and optical properties, spin transport property is also strongly anisotropic.

Induced sadness increases persistence in a simulated slot machine task among recreational gamblers.

PubMed

Devos, Gaëtan; Clark, Luke; Maurage, Pierre; Billieux, Joël

2018-05-01

Gambling may constitute a strategy for coping with depressive mood, but a direct influence of depressive mood on gambling behaviors has never been tested via realistic experimental designs in gamblers. The current study tested whether experimentally induced sadness increases persistence on a simulated slot machine task using real monetary reinforcement in recreational gamblers. Sixty participants were randomly assigned to an experimental (sadness induction) or control (no emotional induction) condition, and then performed a slot machine task consisting of a mandatory phase followed by a persistence phase. Potential confounding variables (problem gambling symptoms, impulsivity traits, gambling cognitions) were measured to ensure that the experimental and control groups were comparable. The study showed that participants in the sadness condition displayed greater gambling persistence than control participants (p = .011). These data support the causal role of negative affect in decisions to gamble and persistence, which bears important theoretical and clinical implications. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The repetition of large-earthquake ruptures.

PubMed Central

Sieh, K

1996-01-01

This survey of well-documented repeated fault rupture confirms that some faults have exhibited a "characteristic" behavior during repeated large earthquakes--that is, the magnitude, distribution, and style of slip on the fault has repeated during two or more consecutive events. In two cases faults exhibit slip functions that vary little from earthquake to earthquake. In one other well-documented case, however, fault lengths contrast markedly for two consecutive ruptures, but the amount of offset at individual sites was similar. Adjacent individual patches, 10 km or more in length, failed singly during one event and in tandem during the other. More complex cases of repetition may also represent the failure of several distinct patches. The faults of the 1992 Landers earthquake provide an instructive example of such complexity. Together, these examples suggest that large earthquakes commonly result from the failure of one or more patches, each characterized by a slip function that is roughly invariant through consecutive earthquake cycles. The persistence of these slip-patches through two or more large earthquakes indicates that some quasi-invariant physical property controls the pattern and magnitude of slip. These data seem incompatible with theoretical models that produce slip distributions that are highly variable in consecutive large events. Images Fig. 3 Fig. 7 Fig. 9 PMID:11607662

Brg1 coordinates multiple processes during retinogenesis and is a tumor suppressor in retinoblastoma

DOE PAGES

Aldiri, Issam; Ajioka, Itsuki; Xu, Beisi; ...

2015-12-01

Retinal development requires precise temporal and spatial coordination of cell cycle exit, cell fate specification, cell migration and differentiation. When this process is disrupted, retinoblastoma, a developmental tumor of the retina, can form. Epigenetic modulators are central to precisely coordinating developmental events, and many epigenetic processes have been implicated in cancer. Studying epigenetic mechanisms in development is challenging because they often regulate multiple cellular processes; therefore, elucidating the primary molecular mechanisms involved can be difficult. Here we explore the role of Brg1 (Smarca4) in retinal development and retinoblastoma in mice using molecular and cellular approaches. Brg1 was found to regulatemore » retinal size by controlling cell cycle length, cell cycle exit and cell survival during development. Brg1 was not required for cell fate specification but was required for photoreceptor differentiation and cell adhesion/polarity programs that contribute to proper retinal lamination during development. The combination of defective cell differentiation and lamination led to retinal degeneration in Brg1-deficient retinae. Despite the hypocellularity, premature cell cycle exit, increased cell death and extended cell cycle length, retinal progenitor cells persisted in Brg1-deficient retinae, making them more susceptible to retinoblastoma. In conclusion, ChIP-Seq analysis suggests that Brg1 might regulate gene expression through multiple mechanisms.« less

Brg1 coordinates multiple processes during retinogenesis and is a tumor suppressor in retinoblastoma

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

Aldiri, Issam; Ajioka, Itsuki; Xu, Beisi

Retinal development requires precise temporal and spatial coordination of cell cycle exit, cell fate specification, cell migration and differentiation. When this process is disrupted, retinoblastoma, a developmental tumor of the retina, can form. Epigenetic modulators are central to precisely coordinating developmental events, and many epigenetic processes have been implicated in cancer. Studying epigenetic mechanisms in development is challenging because they often regulate multiple cellular processes; therefore, elucidating the primary molecular mechanisms involved can be difficult. Here we explore the role of Brg1 (Smarca4) in retinal development and retinoblastoma in mice using molecular and cellular approaches. Brg1 was found to regulatemore » retinal size by controlling cell cycle length, cell cycle exit and cell survival during development. Brg1 was not required for cell fate specification but was required for photoreceptor differentiation and cell adhesion/polarity programs that contribute to proper retinal lamination during development. The combination of defective cell differentiation and lamination led to retinal degeneration in Brg1-deficient retinae. Despite the hypocellularity, premature cell cycle exit, increased cell death and extended cell cycle length, retinal progenitor cells persisted in Brg1-deficient retinae, making them more susceptible to retinoblastoma. In conclusion, ChIP-Seq analysis suggests that Brg1 might regulate gene expression through multiple mechanisms.« less

Accelerated eruption of rat lower incisor. Relationship between impeded and unimpeded eruption rates, rate of attrition, tooth length, and production of dentin and enamel.

PubMed

Risnes, S; Septier, D; Goldberg, M

1995-01-01

The present investigation studies the effects of persistently cutting one lower rat incisor out of occlusion. Within four days, the rate of eruption of the cut (unimpeded) incisor increased to 216% and that of the uncut (impeded) contralateral to 136% of the baseline rate. While the former remained high, the latter decreased gradually to about 90% within three weeks. The rate of attrition of the impeded incisor increased to 233% of the baseline rate within two days, then fell abruptly, and remained at a slightly lower level than the rate of eruption. Accordingly, the length of the erupted part of the impeded incisor decreased initially, but increased gradually after about four days. Measurements made on SEM micrographs of the series of transverse tooth segments obtained when cutting the incisor out of occlusion, showed that growth-related increase in mesiodistal tooth width was arrested from the 10th segment, dentin thickness decreased gradually to about 50% in the 12th segment, and enamel thickness, after an initial increase, decreased to about 80% in the 11th segment. The present study provides experimental evidence that accelerated eruption affects morphogenesis and histogenesis of the rat lower incisor. An impeded incisor, especially the contralateral, may not serve as an ideal control.

Childhood Personality, Betrayal Trauma, and Leukocyte Telomere Length in Adulthood: A Lifespan Perspective on Conscientiousness and Betrayal Traumas as Predictors of a Biomarker of Cellular Aging.

PubMed

Edmonds, Grant W; Hampson, Sarah E; Côté, Hélène C F; Hill, Patrick L; Klest, Bridget

2016-01-01

Conscientiousness is associated with longevity. As such, identifying the biological pathways linking personality to mortality is important. This study employs longitudinal data spanning >40 years to test prospective associations with Leukocyte Telomere Length (LTL), a potential marker of cellular aging. Because telomeres shorten over time, and are sensitive to oxidative stress, shorter LTL may reflect cumulative damage associated with negative health behaviors and past stressful events. We investigated childhood conscientiousness as a protective factor, expecting an association with longer LTL in adulthood, possibly reflecting slower LTL shortening. Potential lifespan pathways involving childhood trauma, smoking behaviors, and Body Mass Index (BMI) were explored. Childhood conscientiousness showed a small raw association with LTL ( r = .08, p = .04), although this effect did not persist when controlling for age and sex. Despite this lack of a direct effect on LTL, we detected an indirect effect operating jointly through BMI and smoking. Higher rates of childhood betrayal trauma were associated with shorter LTL. Contrary to our hypothesis that conscientiousness would buffer this effect, we found evidence for an interaction with childhood betrayal traumas where the association between childhood betrayal traumas and LTL was larger for those higher on conscientiousness in childhood.

Childhood Personality, Betrayal Trauma, and Leukocyte Telomere Length in Adulthood: A Lifespan Perspective on Conscientiousness and Betrayal Traumas as Predictors of a Biomarker of Cellular Aging

PubMed Central

Edmonds, Grant W.; Hampson, Sarah E.; Côté, Hélène C. F.; Hill, Patrick L.; Klest, Bridget

2016-01-01

Conscientiousness is associated with longevity. As such, identifying the biological pathways linking personality to mortality is important. This study employs longitudinal data spanning >40 years to test prospective associations with Leukocyte Telomere Length (LTL), a potential marker of cellular aging. Because telomeres shorten over time, and are sensitive to oxidative stress, shorter LTL may reflect cumulative damage associated with negative health behaviors and past stressful events. We investigated childhood conscientiousness as a protective factor, expecting an association with longer LTL in adulthood, possibly reflecting slower LTL shortening. Potential lifespan pathways involving childhood trauma, smoking behaviors, and Body Mass Index (BMI) were explored. Childhood conscientiousness showed a small raw association with LTL (r = .08, p = .04), although this effect did not persist when controlling for age and sex. Despite this lack of a direct effect on LTL, we detected an indirect effect operating jointly through BMI and smoking. Higher rates of childhood betrayal trauma were associated with shorter LTL. Contrary to our hypothesis that conscientiousness would buffer this effect, we found evidence for an interaction with childhood betrayal traumas where the association between childhood betrayal traumas and LTL was larger for those higher on conscientiousness in childhood. PMID:28018048

Relationship between compliance and persistence with osteoporosis medications and fracture risk in primary health care in France: a retrospective case-control analysis.

PubMed

Cotté, François-Emery; Mercier, Florence; De Pouvourville, Gérard

2008-12-01

Nonadherence to treatment is an important determinant of long-term outcomes in women with osteoporosis. This study was conducted to investigate the association between adherence and osteoporotic fracture risk and to identify optimal thresholds for good compliance and persistence. A secondary objective was to perform a preliminary evaluation of the cost consequences of adherence. This was a retrospective case-control analysis. Data were derived from the Thales prescription database, which contains information on >1.6 million patients in the primary health care setting in France. Cases were women aged >or=50 years who had an osteoporosis-related fracture in 2006. For each case, 5 matched controls were randomly selected. Both compliance and persistence aspects of treatment adherence were examined. Compliance was estimated based on the medication possession ratio (MPR). Persistence was calculated as the time from the initial filling of a prescription for osteoporosis medication until its discontinuation. The mean (SD) MPR was lower in cases compared with controls (58.8% [34.7%] vs 72.1% [28.8%], respectively; P < 0.001). Cases were more likely than controls to discontinue osteoporosis treatment (50.0% vs 25.3%; P < 0.001), yielding a significantly lower proportion of patients who were still persistent at 1 year (34.1% vs 40.9%; P < 0.001). MPR was the best predictor of fracture risk, with an area under the receiver-operating-characteristic curve that was higher than that for persistence (0.59 vs 0.55). The optimal MPR threshold for predicting fracture risk was >or=68.0%. Compared with less-compliant women, women who achieved this threshold had a 51% reduction in fracture risk. The difference in annual drug expenditure between women achieving this threshold and those who did not was approximately euro300. The optimal threshold for persistence with therapy was at least 6 months. Attaining this threshold was associated with a 28% reduction in fracture risk compared with less-persistent women. In this study, better treatment adherence was associated with a greater reduction in fracture risk. Compliance appeared to predict fracture risk better than did persistence.

Influence of trophic position and spatial location on polychlorinated biphenyl (PCB) bioaccumulation in a stream food web

Treesearch

David M. Walters; Ken M. Fritz; Brent R. Johnson; James M. Lazorchak; Frank H. McCormick

2008-01-01

Bioaccumulation of persistent organic contaminants (OCs) is well documented in lentic and marine ecosystems, but few studies have addressed OC bioaccumulation in streams. The limited research in streams is surprising given the magnitude and extent of OC pollution. Approximately 9% of wadeable stream length in the U.S. is underlain by contaminated sediments including...

Performance of EAG and GAG Award Recipients Based on Length and Amount of Aid

ERIC Educational Resources Information Center

Battaglini, Janis K.

2004-01-01

The purpose of this analysis was to examine the persistence, graduation and transfer rates of full-time students who received an EAG (Educational Assistance Grant) or GAG (Guaranteed Access Grant) and matriculated during the 1996-1997 academic year. The performance of these students was examined on the basis of the number of years in which…

Application of monorail fixator for femoral gap nonunion.

PubMed

Agrawal, Hemendra-Kumar; Jaiman, Ashish; Khatkar, Vipin; Sharma, Vinod-Kumar

2014-01-01

Difficult femoral nonunion takes account of infective nonunion and aseptic gap nonunion. Limb length discrepancy and nonunion need to be tackled simultaneously. Conventionally Ilizarov ring fixator is in vogue but it has some limitations. To overcome these, monorail fixator is an effective alternative. Persistent good results can be obtained if we can get a perfect anatomical alignment and good regeneration.

Uniting ecological and genetic data for the conservation of wild ibex

Treesearch

M. K. Schwartz

2009-01-01

There are few taxa more endangered than the Ethiopian Walia ibex. This wild mountain goat inhabits the Simen Mountains of Ethiopia and is known for its enormous backwards curving horns that exceed a meter in length on some males. Historically, hunting and habitat degradation endangered this ibex's persistence. Now this national symbol of Ethiopia is threatened by...

Biological features of hepatitis B virus isolates from patients based on full-length genomic analysis.

PubMed

Wen, Yu-Mei; Wang, Yong-Xiang

2009-01-01

The mechanisms for HBV persistence and the pathogenesis of chronic HB have been shown mainly due to defects in host immune responses. However, HBV isolates with different biological features may also contribute to different clinical outcomes and epidemiological implications in viral hepatitis B (HB). This review presents interesting biological features of HBV isolates based on the structural and functional analysis of full-length HBV isolates from various patients. Among isolates from children after failure of HB vaccination, 129L mutant at the 'a' determinant was found with normal binding efficiency to anti-HBs, but with reduced immunogenicity, which could initiate persistent HBV infections. Isolates from fulminant hepatitis (FH) B patients were not all highly replicative, but differences in capacities of anti-HBs induction could be involved in the pathogenesis of FH. The high replicative competency of isolates from hepatocellular carcinoma (HCC) patients could result in enhanced immune-mediated cytopathic effects against HBV viral proteins, and increased transactivating activity by the X protein. The mechanism of a double-spliced variant in enhancing replication of the wild-type virus is presented. The importance of integrating structural and functional analysis to reveal biological features of HBV isolates in viral pathogenesis is discussed.

Cofilin Increases the Bending Flexibility of Actin Filaments: Implications for Severing and Cell Mechanics

PubMed Central

McCullough, Brannon R.; Blanchoin, Laurent; Martiel, Jean-Louis; De La Cruz, Enrique M.

2009-01-01

We determined the flexural (bending) rigidities of actin and cofilactin filaments from a cosine correlation function analysis of their thermally driven, two-dimensional fluctuations in shape. The persistence length of actin filaments is 9.8 µm, corresponding to a flexural rigidity of 0.040 pN µm2. Cofilin binding lowers the persistence length ∼5-fold to a value of 2.2 µm and the filament flexural rigidity to 0.0091 pN µm2. That cofilin-decorated filaments are more flexible than native filaments despite an increased mass indicates that cofilin binding weakens and redistributes stabilizing subunit interactions of filaments. We favor a mechanism in which the increased flexibility of cofilin-decorated filaments results from the linked dissociation of filament-stabilizing ions and reorganization of actin subdomain 2 and as a consequence promotes severing due to a mechanical asymmetry. Knowledge of the effects of cofilin on actin filament bending mechanics, together with our previous analysis of torsional stiffness, provide a quantitative measure of the mechanical changes in actin filaments associated with cofilin binding, and suggest that the overall mechanical and force-producing properties of cells can be modulated by cofilin activity. PMID:18617188

Performance analysis for bounded persistent disturbances in PD/PID-controlled robotic systems with its experimental demonstrations

NASA Astrophysics Data System (ADS)

Kim, Jung Hoon; Hur, Sung-Moon; Oh, Yonghwan

2018-03-01

This paper is concerned with performance analysis of proportional-derivative/proportional-integral-derivative (PD/PID) controller for bounded persistent disturbances in a robotic manipulator. Even though the notion of input-to-state stability (ISS) has been widely used to deal with the effect of disturbances in control of a robotic manipulator, the corresponding studies cannot be directly applied to the treatment of persistent disturbances occurred in robotic manipulators. This is because the conventional studies relevant to ISS consider the H∞ performance for robotic systems, which is confined to the treatment of decaying disturbances, i.e. the disturbances those in the L2 space. To deal with the effect of persistent disturbances in robotic systems, we first provide a new treatment of ISS in the L∞ sense because bounded persistent disturbances should be intrinsically regarded as elements of the L∞ space. We next derive state-space representations of trajectory tracking control in the robotic systems which allow us to define the problem formulations more clearly. We then propose a novel control law that has a PD/PID control form, by which the trajectory tracking system satisfies the reformulated ISS. Furthermore, we can obtain a theoretical argument about the L∞ gain from the disturbance to the regulated output through the proposed control law. Finally, experimental studies for a typical 3-degrees of freedom robotic manipulator are given to demonstrate the effectiveness of the method introduced in this paper.

Preoperative automated fibre quantification predicts postoperative seizure outcome in temporal lobe epilepsy.

PubMed

Keller, Simon S; Glenn, G Russell; Weber, Bernd; Kreilkamp, Barbara A K; Jensen, Jens H; Helpern, Joseph A; Wagner, Jan; Barker, Gareth J; Richardson, Mark P; Bonilha, Leonardo

2017-01-01

Approximately one in every two patients with pharmacoresistant temporal lobe epilepsy will not be rendered completely seizure-free after temporal lobe surgery. The reasons for this are unknown and are likely to be multifactorial. Quantitative volumetric magnetic resonance imaging techniques have provided limited insight into the causes of persistent postoperative seizures in patients with temporal lobe epilepsy. The relationship between postoperative outcome and preoperative pathology of white matter tracts, which constitute crucial components of epileptogenic networks, is unknown. We investigated regional tissue characteristics of preoperative temporal lobe white matter tracts known to be important in the generation and propagation of temporal lobe seizures in temporal lobe epilepsy, using diffusion tensor imaging and automated fibre quantification. We studied 43 patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis and 44 healthy controls. Patients underwent preoperative imaging, amygdalohippocampectomy and postoperative assessment using the International League Against Epilepsy seizure outcome scale. From preoperative imaging, the fimbria-fornix, parahippocampal white matter bundle and uncinate fasciculus were reconstructed, and scalar diffusion metrics were calculated along the length of each tract. Altogether, 51.2% of patients were rendered completely seizure-free and 48.8% continued to experience postoperative seizure symptoms. Relative to controls, both patient groups exhibited strong and significant diffusion abnormalities along the length of the uncinate bilaterally, the ipsilateral parahippocampal white matter bundle, and the ipsilateral fimbria-fornix in regions located within the medial temporal lobe. However, only patients with persistent postoperative seizures showed evidence of significant pathology of tract sections located in the ipsilateral dorsal fornix and in the contralateral parahippocampal white matter bundle. Using receiver operating characteristic curves, diffusion characteristics of these regions could classify individual patients according to outcome with 84% sensitivity and 89% specificity. Pathological changes in the dorsal fornix were beyond the margins of resection, and contralateral parahippocampal changes may suggest a bitemporal disorder in some patients. Furthermore, diffusion characteristics of the ipsilateral uncinate could classify patients from controls with a sensitivity of 98%; importantly, by co-registering the preoperative fibre maps to postoperative surgical lacuna maps, we observed that the extent of uncinate resection was significantly greater in patients who were rendered seizure-free, suggesting that a smaller resection of the uncinate may represent insufficient disconnection of an anterior temporal epileptogenic network. These results may have the potential to be developed into imaging prognostic markers of postoperative outcome and provide new insights for why some patients with temporal lobe epilepsy continue to experience postoperative seizures. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain.

Preoperative automated fibre quantification predicts postoperative seizure outcome in temporal lobe epilepsy

PubMed Central

Keller, Simon S; Glenn, G Russell; Weber, Bernd; Kreilkamp, Barbara A K; Jensen, Jens H; Helpern, Joseph A; Wagner, Jan; Barker, Gareth J; Richardson, Mark P; Bonilha, Leonardo

2017-01-01

Abstract Approximately one in every two patients with pharmacoresistant temporal lobe epilepsy will not be rendered completely seizure-free after temporal lobe surgery. The reasons for this are unknown and are likely to be multifactorial. Quantitative volumetric magnetic resonance imaging techniques have provided limited insight into the causes of persistent postoperative seizures in patients with temporal lobe epilepsy. The relationship between postoperative outcome and preoperative pathology of white matter tracts, which constitute crucial components of epileptogenic networks, is unknown. We investigated regional tissue characteristics of preoperative temporal lobe white matter tracts known to be important in the generation and propagation of temporal lobe seizures in temporal lobe epilepsy, using diffusion tensor imaging and automated fibre quantification. We studied 43 patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis and 44 healthy controls. Patients underwent preoperative imaging, amygdalohippocampectomy and postoperative assessment using the International League Against Epilepsy seizure outcome scale. From preoperative imaging, the fimbria-fornix, parahippocampal white matter bundle and uncinate fasciculus were reconstructed, and scalar diffusion metrics were calculated along the length of each tract. Altogether, 51.2% of patients were rendered completely seizure-free and 48.8% continued to experience postoperative seizure symptoms. Relative to controls, both patient groups exhibited strong and significant diffusion abnormalities along the length of the uncinate bilaterally, the ipsilateral parahippocampal white matter bundle, and the ipsilateral fimbria-fornix in regions located within the medial temporal lobe. However, only patients with persistent postoperative seizures showed evidence of significant pathology of tract sections located in the ipsilateral dorsal fornix and in the contralateral parahippocampal white matter bundle. Using receiver operating characteristic curves, diffusion characteristics of these regions could classify individual patients according to outcome with 84% sensitivity and 89% specificity. Pathological changes in the dorsal fornix were beyond the margins of resection, and contralateral parahippocampal changes may suggest a bitemporal disorder in some patients. Furthermore, diffusion characteristics of the ipsilateral uncinate could classify patients from controls with a sensitivity of 98%; importantly, by co-registering the preoperative fibre maps to postoperative surgical lacuna maps, we observed that the extent of uncinate resection was significantly greater in patients who were rendered seizure-free, suggesting that a smaller resection of the uncinate may represent insufficient disconnection of an anterior temporal epileptogenic network. These results may have the potential to be developed into imaging prognostic markers of postoperative outcome and provide new insights for why some patients with temporal lobe epilepsy continue to experience postoperative seizures. PMID:28031219

Differences in placental telomere length suggest a link between racial disparities in birth outcomes and cellular aging

PubMed Central

JONES, Christopher W.; GAMBALA, Cecilia; ESTEVES, Kyle C.; WALLACE, Maeve; SCHLESINGER, Reid; O’QUINN, Marguerite; KIDD, Laura; THEALL, Katherine P.; DRURY, Stacy S.

2017-01-01

BACKGROUND Health disparities begin early in life and persist across the life course. Despite current efforts Black women exhibit greater risk for pregnancy complications and negative perinatal outcomes compared to White women. The placenta, a complex multi-tissue organ, serves as the primary transducer of bidirectional information between the mother and fetus. Altered placental function is linked to multiple racially disparate pregnancy complications, however little is known about racial differences in molecular factors within the placenta. Several pregnancy complications, including preeclampsia and fetal growth restriction, exhibit racial disparities and are associated with shorter placental telomere length, an indicator of cellular stress and aging. Cellular senescence and telomere dynamics are linked to the molecular mechanisms associated with the onset of labor and parturition. Further, racial differences in telomere length are found in a range of different peripheral tissues. Together these factors suggest that exploration of racial differences in telomere length of the placenta may provide novel mechanistic insight into racial disparities in birth outcomes. OBJECTIVE This study examined whether telomere length measured in four distinct fetally-derived tissues were significantly different between Blacks and Whites. The study had two hypotheses: (1) that telomere length measured in different placental tissue types would be correlated and (2) that across all sampled tissues telomere length would differ by race. STUDY DESIGN In a prospective study, placental tissue samples were collected from the amnion, chorion, villus, and umbilical cord from Black and White singleton pregnancies (N=46). Telomere length was determined using monochrome multiplex quantitative real-time polymerase chain reaction in each placental tissue. Demographic and pregnancy-related data were also collected. Descriptive statistics characterized the sample overall and among Black and White women separately. The overall impact of race was assessed by multilevel mixed-effects linear regression models that included empirically relevant covariates. RESULTS Telomere length was significantly correlated across all placental tissues. Pairwise analyses of placental tissue telomere length revealed significantly longer telomere length in the amnion compared to the chorion (t=−2.06, p=0.043). Overall telomere length measured in placenta samples from Black mothers were significantly shorter than those from White mothers (β=−0.09, p=0.04). Controlling for relevant maternal and infant characteristics strengthened the significance of the observed racial differences (β=−0.12, p=0.02). Within tissue analyses revealed that the greatest difference by race was found in chorionic telomere length (t=−2.81, p=0.007). CONCLUSION These findings provide the first evidence of racial differences in placental telomere length. Telomere length was significantly shorter in placental samples derived from Black mothers compared to White. Given previous studies reporting that telomere length, cellular senescence, and telomere dynamics are molecular factors contributing to the rupture of the amniotic sac, onset of labor, and parturition, our findings of shorter telomere length in placentas from Black mothers suggests that accelerated cellular aging across placental tissues may be relevant to the increased risk of preterm delivery in Blacks. Our results suggest that racial differences in cellular aging in the placenta contribute to the earliest roots of health disparities. PMID:27865975

Impaired reward processing in the human prefrontal cortex distinguishes between persistent and remittent attention deficit hyperactivity disorder.

PubMed

Wetterling, Friedrich; McCarthy, Hazel; Tozzi, Leonardo; Skokauskas, Norbert; O'Doherty, John P; Mulligan, Aisling; Meaney, James; Fagan, Andrew J; Gill, Michael; Frodl, Thomas

2015-11-01

Symptoms of attention deficit hyperactivity disorder (ADHD) in children often persist into adulthood and can lead to severe antisocial behavior. However, to-date it remains unclear whether neuro-functional abnormalities cause ADHD, which in turn can then provide a marker of persistent ADHD. Using event-related functional magnetic resonance imaging (fMRI), we measured blood oxygenation level dependent (BOLD) signal changes in subjects during a reversal learning task in which choice of the correct stimulus led to a probabilistically determined 'monetary' reward or punishment. Participants were diagnosed with ADHD during their childhood (N=32) and were paired with age, gender, and education matched healthy controls (N=32). Reassessment of the ADHD group as adults resulted in a split between either persistent (persisters, N=17) or remitted ADHDs (remitters, N=15). All three groups showed significantly decreased activation in the medial prefrontal cortex (PFC) and the left striatum during punished correct responses, however only remitters and controls presented significant psycho-physiological interaction between these fronto-striatal reward and outcome valence networks. Comparing persisters to remitters and controls showed significantly inverted responses to punishment (P<0.05, family-wise error corrected) in left PFC region. Interestingly, the decreased activation shown after punishment was located in different areas of the PFC for remitters compared with controls, suggesting that remitters might have learned compensation strategies to overcome their ADHD symptoms. Thus, fMRI helps understanding the neuro-functional basis of ADHD related behavior differences and differentiates between persistent and remittent ADHD. © 2015 Wiley Periodicals, Inc.

Single-stage operation without temporary colostomy for persistent cloaca with a short common channel.

PubMed

Masuko, T; Higashimoto, Y; Iwai, J

2005-11-01

Colorectal decompression with a catheter was performed for evacuation of stool before definitive surgery in two patients with a persistent cloaca. Two newborn female infants with persistent cloaca received placement of a silicone balloon-tipped catheter in the rectum via the cloacal orifice under fluoroscopic guidance at the time of diagnosis. The length of the cloaca was 2 and 1.5 cm, respectively. The diameter of the catheter was matched to the patients' rectal size and the open end was wrapped in a diaper to allow continuous drainage of stool. The infants underwent bowel irrigation with warm saline thrice a day, at home. Total urogenital mobilization was carried out in the infants at the age of 7 and 8 months, respectively. Both infants had no abdominal distension, colorectal dilatation, or urinary tract infection while the catheter was in situ. The postoperative course was uneventful, except for minimal wound dehiscence in one patient. At present, both infants can void spontaneously without any urological problems. In infants with a persistent cloaca less than 3 cm long and normal urinary tract function, adequate evacuation of stool may be achieved by colorectal decompression with a catheter, thus avoiding the need for a colostomy.

The natural history of penile length after radical prostatectomy: a long-term prospective study.

PubMed

Vasconcelos, Juliana Souza; Figueiredo, Rui Teófilo; Nascimento, Fabio Luis Branco; Damião, Ronaldo; da Silva, Eloisio Alexsandro

2012-12-01

To describe the penile length after radical prostatectomy (RP) in a long-term follow-up. We evaluated prospectively the penile length of 105 patients with localized prostate cancer treated by open RP. Participants using therapy for penile rehabilitation were excluded from statistical analysis. Measurements of the stretched penis were taken preoperatively and at 3, 6, 12, 24, 36, 48, and 60 months postoperatively. The International Index of Erectile Function-Erectile Function (IIEF-EF) questionnaire was used to evaluate erectile function. The penile anthropometric measure used was the stretched length of the flaccid penis, from the pubopenile skin angle to the end of the glans, after the prepubic fat was depressed under maximum manual traction. The mean stretched penile length 3 months after RP decreased an average of 1 cm from baseline (P <.001). This mean difference persisted until 24 months. At 36 months, the penile length differed 0.6 cm. At 48 months (-0.3 cm) and 60 months (+0.4 cm), the mean differences in penile length before and after RP were not significant (P = .080 and P = .065, respectively). Erectile function was a predictor for early return of penile length. Nearly 1 cm of penile shortening after RP may be expected up to 12 months. However, a trend toward recovery of penile length occurs after 24 months of follow-up and is completely re-established after 48 months. The preserved erectile function after RP is a predictor for penile length recovery. Copyright © 2012 Elsevier Inc. All rights reserved.

The Alternative Sigma Factors SigE and SigB Are Involved in Tolerance and Persistence to Antitubercular Drugs

PubMed Central

Pisu, Davide; Provvedi, Roberta; Espinosa, Dulce Mata; Payan, Jorge Barrios; Boldrin, Francesca; Palù, Giorgio; Hernandez-Pando, Rogelio

2017-01-01

ABSTRACT The emergence and spread of drug-resistant Mycobacterium tuberculosis strains possibly threaten our ability to treat this disease in the future. Even though two new antitubercular drugs have recently been introduced, there is still the need to design new molecules whose mechanisms of action could reduce the length of treatment. We show that two alternative sigma factors of M. tuberculosis (SigE and SigB) have a major role in determining the level of basal resistance to several drugs and the amount of persisters surviving long-duration drug treatment. We also demonstrate that ethambutol, a bacteriostatic drug, is highly bactericidal for M. tuberculosis mutants missing either SigE or SigB. We suggest that molecules able to interfere with the activity of SigE or SigB not only could reduce M. tuberculosis virulence in vivo but also could boost the effect of other drugs by increasing the sensitivity of the organism and reducing the number of persisters able to escape killing. PMID:28993339

Steering cell migration by alternating blebs and actin-rich protrusions.

PubMed

Diz-Muñoz, Alba; Romanczuk, Pawel; Yu, Weimiao; Bergert, Martin; Ivanovitch, Kenzo; Salbreux, Guillaume; Heisenberg, Carl-Philipp; Paluch, Ewa K

2016-09-02

High directional persistence is often assumed to enhance the efficiency of chemotactic migration. Yet, cells in vivo usually display meandering trajectories with relatively low directional persistence, and the control and function of directional persistence during cell migration in three-dimensional environments are poorly understood. Here, we use mesendoderm progenitors migrating during zebrafish gastrulation as a model system to investigate the control of directional persistence during migration in vivo. We show that progenitor cells alternate persistent run phases with tumble phases that result in cell reorientation. Runs are characterized by the formation of directed actin-rich protrusions and tumbles by enhanced blebbing. Increasing the proportion of actin-rich protrusions or blebs leads to longer or shorter run phases, respectively. Importantly, both reducing and increasing run phases result in larger spatial dispersion of the cells, indicative of reduced migration precision. A physical model quantitatively recapitulating the migratory behavior of mesendoderm progenitors indicates that the ratio of tumbling to run times, and thus the specific degree of directional persistence of migration, are critical for optimizing migration precision. Together, our experiments and model provide mechanistic insight into the control of migration directionality for cells moving in three-dimensional environments that combine different protrusion types, whereby the proportion of blebs to actin-rich protrusions determines the directional persistence and precision of movement by regulating the ratio of tumbling to run times.

Influence of scale-dependent fracture intensity on block size distribution and rock slope failure mechanisms in a DFN framework

NASA Astrophysics Data System (ADS)

Agliardi, Federico; Galletti, Laura; Riva, Federico; Zanchi, Andrea; Crosta, Giovanni B.

2017-04-01

An accurate characterization of the geometry and intensity of discontinuities in a rock mass is key to assess block size distribution and degree of freedom. These are the main controls on the magnitude and mechanisms of rock slope instabilities (structurally-controlled, step-path or mass failures) and rock mass strength and deformability. Nevertheless, the use of over-simplified discontinuity characterization approaches, unable to capture the stochastic nature of discontinuity features, often hampers a correct identification of dominant rock mass behaviour. Discrete Fracture Network (DFN) modelling tools have provided new opportunities to overcome these caveats. Nevertheless, their ability to provide a representative picture of reality strongly depends on the quality and scale of field data collection. Here we used DFN modelling with FracmanTM to investigate the influence of fracture intensity, characterized on different scales and with different techniques, on the geometry and size distribution of generated blocks, in a rock slope stability perspective. We focused on a test site near Lecco (Southern Alps, Italy), where 600 m high cliffs in thickly-bedded limestones folded at the slope scale impend on the Lake Como. We characterized the 3D slope geometry by Structure-from-Motion photogrammetry (range: 150-1500m; point cloud density > 50 pts/m2). Since the nature and attributes of discontinuities are controlled by brittle failure processes associated to large-scale folding, we performed a field characterization of meso-structural features (faults and related kinematics, vein and joint associations) in different fold domains. We characterized the discontinuity populations identified by structural geology on different spatial scales ranging from outcrops (field surveys and photo-mapping) to large slope sectors (point cloud and photo-mapping). For each sampling domain, we characterized discontinuity orientation statistics and performed fracture mapping and circular window analyses in order to measure fracture intensity (P21) and persistence (trace length distributions). Then, we calibrated DFN models for different combinations of P21/P32 and trace length distributions, characteristic of data collected on different scale. Comparing fracture patterns and block size distributions obtained from different models, we outline the strong influence of field data quality and scale on the rock mass behaviours predicted by DFN. We show that accounting for small scale features (close but short fractures) results in smaller but more interconnected blocks, eventually characterized by low removability and partly supported by intact rock strength. On the other hand, DFN based on data surveyed on slope scale enhance the structural control of persistent fracture on the kinematic degree-of freedom of medium-sized blocks, with significant impacts on the selection and parametrization of rock slope stability modelling approaches.

Mathematical model for path selection by ants between nest and food source.

PubMed

Bodnar, Marek; Okińczyc, Natalia; Vela-Pérez, M

2017-03-01

Several models have been proposed to describe the behavior of ants when moving from nest to food sources. Most of these studies where based on numerical simulations with no mathematical justification. In this paper, we propose a mechanism for the formation of paths of minimal length between two points by a collection of individuals undergoing reinforced random walks taking into account not only the lengths of the paths but also the angles (connected to the preference of ants to move along straight lines). Our model involves reinforcement (pheromone accumulation), persistence (tendency to preferably follow straight directions in absence of any external effect) and takes into account the bifurcation angles of each edge (represented by a probability of willingness of choosing the path with the smallest angle). We describe analytically the results for 2 ants and different path lengths and numerical simulations for several ants. Copyright © 2016 Elsevier Inc. All rights reserved.

Persistence and spreading of field and vaccine strains of infectious laryngotracheitis virus (ILTV) in vaccinated and unvaccinated geographic regions, in Brazil.

PubMed

Chacón, Jorge Luis; Núñez, Luis Fabian Naranjo; Vejarano, Maria Pilar; Parra, Silvana Hipatia Santander; Astolfi-Ferreira, Claudete Serrano; Ferreira, Antonio José Piantino

2015-08-01

Infectious laryngotracheitis (ILT) is a highly infectious respiratory disease that causes morbidity and mortality in commercial chickens. Despite the use of attenuated vaccines, ILT outbreaks have been described in broiler and long-lived birds. Molecular approaches, including polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing, are used to characterize ILT viruses (ILTVs) detected in vaccinated and unvaccinated geographical regions. As part of an ILT control program implemented in a region of commercial layer production, samples of conjunctiva, trachea, and trigeminal ganglia were collected from chickens in a vaccinated and quarantined region over a period of 8 years after initiation of vaccination. To determine the origin of new ILT outbreaks in unvaccinated regions, samples collected from ill chickens were also analyzed. Chicken embryo origin (CEO) vaccine viruses and the Bastos field strain were detected circulating in healthy chickens in the vaccinated region. CEO strains and field viruses molecularly related to the Bastos strain were also detected outside of the quarantined region in chickens showing clinical signs of ILT. This study reveals the persistence and circulation of a wild field strain, despite the intensive use of tissue culture origin (TCO) and CEO vaccines in a quarantined region. Spreading of CEO viruses to unvaccinated regions and the capacity of this virus to establish latent infections and cause severe outbreaks were also observed.

The etiology of pectus carinatum involves overgrowth of costal cartilage and undergrowth of ribs.

PubMed

Park, Chul Hwan; Kim, Tae Hoon; Haam, Seok Jin; Jeon, Inhwan; Lee, Sungsoo

2014-08-01

We compared the length of costal cartilage and rib between patients with symmetric pectus carinatum and controls without anterior chest wall protrusion, using a 3-dimensional (3D) computed tomography (CT) to evaluate whether the overgrowth of costal cartilage exists in patients with pectus carinatum. Twenty-six patients with symmetric pectus carinatum and matched twenty-six controls without chest wall protrusion were enrolled. We measured the full lengths of the 4th-6th ribs and costal cartilages using 3-D volume rendering CT images and the curved multiplanar reformatted (MPR) techniques. The lengths of ribs and costal cartilages, the summation of rib and costal cartilage lengths, and the costal index [length of cartilage/length of rib * 100 (%)] were compared between the patients group and the control group at 4th-6th levels. The lengths of costal cartilage in patient group were significantly longer than those of control group at 4th, 5th and 6th rib level. The lengths of ribs in patient group were significantly shorter than those of control group at 4th, 5th and 6th rib level. The summations of rib and costal cartilage lengths were not longer in patients group than in control group. The costal indices were significantly larger in patients group than in control groups at 4th, 5th and 6th rib level. In patients with symmetric pectus carinatum, the lengths of costal cartilage were longer but the lengths of rib were shorter than those of controls. These findings may supports that the overgrowth of costal cartilage was not the only factor responsible for pectus carinatum. Copyright © 2014 Elsevier Inc. All rights reserved.

Obg and Membrane Depolarization Are Part of a Microbial Bet-Hedging Strategy that Leads to Antibiotic Tolerance.

PubMed

Verstraeten, Natalie; Knapen, Wouter Joris; Kint, Cyrielle Ines; Liebens, Veerle; Van den Bergh, Bram; Dewachter, Liselot; Michiels, Joran Elie; Fu, Qiang; David, Charlotte Claudia; Fierro, Ana Carolina; Marchal, Kathleen; Beirlant, Jan; Versées, Wim; Hofkens, Johan; Jansen, Maarten; Fauvart, Maarten; Michiels, Jan

2015-07-02

Within bacterial populations, a small fraction of persister cells is transiently capable of surviving exposure to lethal doses of antibiotics. As a bet-hedging strategy, persistence levels are determined both by stochastic induction and by environmental stimuli called responsive diversification. Little is known about the mechanisms that link the low frequency of persisters to environmental signals. Our results support a central role for the conserved GTPase Obg in determining persistence in Escherichia coli in response to nutrient starvation. Obg-mediated persistence requires the stringent response alarmone (p)ppGpp and proceeds through transcriptional control of the hokB-sokB type I toxin-antitoxin module. In individual cells, increased Obg levels induce HokB expression, which in turn results in a collapse of the membrane potential, leading to dormancy. Obg also controls persistence in Pseudomonas aeruginosa and thus constitutes a conserved regulator of antibiotic tolerance. Combined, our findings signify an important step toward unraveling shared genetic mechanisms underlying persistence. Copyright © 2015 Elsevier Inc. All rights reserved.

The relation between persistent coma and brain ischemia after severe brain injury.

PubMed

Cheng, Quan; Jiang, Bing; Xi, Jian; Li, Zhen Yan; Liu, Jin Fang; Wang, Jun Yu

2013-12-01

To investigate the relation between brain ischemia and persistent vegetative state after severe traumatic brain injury. The 66 patients with severe brain injury were divided into two groups: The persistent coma group (coma duration ≥10 d) included 51 patients who had an admission Glasgow Coma Scale (GCS) of 5-8 and were unconscious for more than 10 d. There were 15 patients in the control group, their admission GCS was 5-8, and were unconscious for less than 10 d. The brain areas, including frontal, parietal, temporal, occipital lobes and thalamus, were measured by Single Photon Emission Computed Tomography (SPECT). In the first SPECT scan, multiple areas of cerebral ischemia were documented in all patients in both groups, whereas bilateral thalamic ischemia were presented in all patients in the persistent coma group and were absented in the control group. In the second SPECT scan taken during the period of analepsia, with an indication that unilateral thalamic ischemia were persisted in 28 of 41 patients in persistent coma group(28/41,68.29%). Persistent coma after severe brain injury is associated with bilateral thalamic ischemia.

Directional Solidification and Convection in Small Diameter Crucibles

NASA Technical Reports Server (NTRS)

Chen, J.; Sung, P. K.; Tewari, S. N.; Poirier, D. R.; DeGroh, H. C., III

2003-01-01

Pb-2.2 wt% Sb alloy was directionally solidified in 1, 2, 3 and 7 mm diameter crucibles. Pb-Sb alloy presents a solutally unstable case. Under plane-front conditions, the resulting macrosegregation along the solidified length indicates that convection persists even in the 1 mm diameter crucible. Al-2 wt% Cu alloy was directionally solidified because this alloy was expected to be stable with respect to convection. Nevertheless, the resulting macrosegregation pattern and the microstructure in solidified examples indicated the presence of convection. Simulations performed for both alloys show that convection persists for crucibles as small as 0.6 mm of diameter. For the solutally stable alloy, Al-2 wt% Cu, the simulations indicate that the convection arises from a lateral temperature gradient.

The Long Range Persistence of Wakes Behind a Row of Roughness Elements

NASA Technical Reports Server (NTRS)

Goldstein, M. E.; Sescu, Adrian; Duck, Peter W.; Choudhari, Meelan

2010-01-01

We consider a periodic array of relatively small roughness elements whose spanwise separation is of the order of the local boundary-layer thickness and construct a local asymptotic high-Reynolds-number solution that is valid in the vicinity of the roughness. The resulting flow decays on the very short streamwise length scale of the roughness, but the solution eventually becomes invalid at large downstream distances and a new solution has to be constructed in the downstream region. This latter result shows that the roughness-generated wakes can persist over very long streamwise distances, which are much longer than the distance between the roughness elements and the leading edge. Detailed numerical results are given for the far wake structure.

African hair length in a school population: a clue to disease pathogenesis?

PubMed

Khumalo, N P; Gumedze, F

2007-09-01

Anecdotal data suggest that combed natural African hair reaches a length steady state. Easier grooming and anticipated long hair have made relaxers popular. These hypotheses were tested in a cross-sectional survey of 1042 school children using a piloted questionnaire and hair length measurements done on four scalp regions. Participants included 45% boys and 55% girls. Girls consider length important for hairstyle choice (P < 0.0001). There was no difference in mean length at 2 to 5 vs. > 5 years (P = 0.3) and at 1 to < 2 vs. 2 to 5 years (P = 0.99), suggesting that a steady state is reached within 1 year after a hair cut for combed natural hair [mean, 5.1 cm (4.3)]. Relaxed hair reached length steady state > 2 years after a haircut [mean, 10.9 cm (3.6)], was longer than natural hair (P < 0.0001), shorter than expected, and significantly shorter on the occiput than the rest of the scalp (P < 0.0001). Persistently short combed natural hair years after a hair cut suggests that breakage eventually equals new growth (i.e., steady state), which is likely to be variable. Relaxed hair, irrespective of last haircut, is also short; chemical damage as a limit to potential lengths needs confirmation. Relatively short occipital relaxed hair could be a clue to disease pathogenesis.

The impact of persistent visually disabling vitreous floaters on health status utility values.

PubMed

Zou, Haidong; Liu, Haiyun; Xu, Xun; Zhang, Xi

2013-08-01

To assess the time trade-off (TTO) utility values in patients with persistent visually disabling vitreous floaters (DVF) and to determine the reliability and validity of TTO methods in DVF patients. Prospective cross-sectional questionnaire survey: Eligible patients with persistent DVF referred to the Shanghai First People's Hospital outpatient service between January 2006 and February 2010, and randomly selected normal vision general population residents, were enrolled. All participants underwent TTO utility value evaluation. After 4-5 weeks, the patients were asked to undergo second TTO utility value evaluation during the follow-up interview. The mean initial utility values of the 107 persistent DVF patients were 0.904 ± 0.054. Regression analyses revealed that length of education, visual acuity in the poorer-vision eye and employment status were associated with utility values (all P < 0.01). All patients took part in the follow-up interview; the intra-class correlation coefficient for TTO utility values at the initial and follow-up interviews was 0.855. In the 91 general population residents, the mean utility value was 0.923 ± 0.032, which was statistically higher than that of active study patients (t = 3.01, P < 0.01). Persistent DVF can substantially diminish the patients' perception of their life, and can be measured by TTO utility values with high reliability and construct validity.

Supercoiled Minivector DNA resists shear forces associated with gene therapy delivery

PubMed Central

Catanese, D J; Fogg, J M; Schrock, D E; Gilbert, B E; Zechiedrich, L

2012-01-01

Supercoiled DNAs varying from 281 to 5302 bp were subjected to shear forces generated by aerosolization or sonication. DNA shearing strongly correlated with length. Typical sized plasmids (⩾3000 bp) degraded rapidly. DNAs 2000–3000 bp persisted ∼10 min. Even in the absence of condensing agents, supercoiled DNA <1200 bp survived nebulization, and increased forces of sonication were necessary to shear it. Circular vectors were considerably more resistant to shearing than linear vectors of the same length. DNA supercoiling afforded additional protection. These results show the potential of shear-resistant Minivector DNAs to overcome one of the major challenges associated with gene therapy delivery. PMID:21633394

Persistence, Transmission, and Virulence Characteristics of Aeromonas Strains in a Duckweed Aquaculture-Based Hospital Sewage Water Recycling Plant in Bangladesh▿

PubMed Central

Rahman, Mokhlasur; Huys, Geert; Rahman, Motiur; Albert, M. John; Kühn, Inger; Möllby, Roland

2007-01-01

The persistence and transmission of Aeromonas in a duckweed aquaculture-based hospital sewage water treatment plant in Bangladesh was studied. A total of 670 samples from different sites of the hospital sewage water treatment plant, from feces of hospitalized children suffering from diarrhea, from environmental control ponds, and from feces of healthy humans were collected over a period of three years. In total, 1,315 presumptive Aeromonas isolates were biochemically typed by the PhenePlate rapid screening system (PhP-AE). A selection of 90 representative isolates was further analyzed with PhenePlate (PhP) extended typing (PhP-48), fatty acid methyl ester analysis, and amplified fragment length polymorphism (AFLP) fingerprinting. In addition, the prevalence of the putative virulence factors hemolysin and cytotoxin and the presence of the cytolytic enterotoxin gene (AHCYTOEN) were analyzed. Aeromonas was found at all sites of the treatment plant, in 40% of the samples from environmental control ponds, in 8.5% of the samples from hospitalized children suffering from diarrhea, and in 3.5% of samples from healthy humans. A significantly high number of Aeromonas bacteria was found in duckweed, which indicates that duckweed may serve as a reservoir for these bacteria. PhP-AE typing allowed identification of more than 192 distinct PhP types, of which 18 major PhP types (MTs) were found in multiple sites and during several occasions. AFLP fingerprinting revealed the prevalence of genotypically indistinguishable Aeromonas isolates among certain PhP MTs recovered from different sampling occasions and/or at multiple sites. Hemolytic and cytotoxic activities were observed in 43% of the tested strains, whereas 29% possessed the cytolytic enterotoxin gene AHCYTOEN. Collectively, two specific MTs associated with diarrhea were shown to exhibit high cytotoxicity. Furthermore, all tested isolates of these major types were positive for the cytolytic enterotoxin gene. In conclusion, our data indicate that certain phenotypically and genotypically stable clonal lineages of Aeromonas have persisted in the treatment system for a prolonged period and might spread from the hospitalized children suffering from diarrhea to fish produced for human consumption through the sewage water treatment system. PMID:17194839

Determining the optimal window length for pattern recognition-based myoelectric control: balancing the competing effects of classification error and controller delay.

PubMed

Smith, Lauren H; Hargrove, Levi J; Lock, Blair A; Kuiken, Todd A

2011-04-01

Pattern recognition-based control of myoelectric prostheses has shown great promise in research environments, but has not been optimized for use in a clinical setting. To explore the relationship between classification error, controller delay, and real-time controllability, 13 able-bodied subjects were trained to operate a virtual upper-limb prosthesis using pattern recognition of electromyogram (EMG) signals. Classification error and controller delay were varied by training different classifiers with a variety of analysis window lengths ranging from 50 to 550 ms and either two or four EMG input channels. Offline analysis showed that classification error decreased with longer window lengths (p < 0.01 ). Real-time controllability was evaluated with the target achievement control (TAC) test, which prompted users to maneuver the virtual prosthesis into various target postures. The results indicated that user performance improved with lower classification error (p < 0.01 ) and was reduced with longer controller delay (p < 0.01 ), as determined by the window length. Therefore, both of these effects should be considered when choosing a window length; it may be beneficial to increase the window length if this results in a reduced classification error, despite the corresponding increase in controller delay. For the system employed in this study, the optimal window length was found to be between 150 and 250 ms, which is within acceptable controller delays for conventional multistate amplitude controllers.

The social transmission of metacontrol policies: Mechanisms underlying the interpersonal transfer of persistence and flexibility.

PubMed

Hommel, Bernhard; Colzato, Lorenza S

2017-10-01

Humans often face binary cognitive-control dilemmas, with the choice between persistence and flexibility being a crucial one. Tackling these dilemmas requires metacontrol, i.e., the control of the current cognitive-control policy. As predicted from functional, psychometric, neuroscientific, and modeling approaches, interindividual variability in metacontrol biases towards persistence or flexibility could be demonstrated in metacontrol-sensitive tasks. These biases covary systematically with genetic predispositions regarding mesofrontal and nigrostriatal dopaminergic functioning and the individualistic or collectivistic nature of the cultural background. However, there is also evidence for mood- and meditation-induced intraindividual variability (with negative mood and focused-attention meditation being associated with a bias towards persistence, and positive mood and open-monitoring meditation being associated with a bias towards flexibility), suggesting that genetic and cultural factors do not determine metacontrol settings entirely. We suggest a theoretical framework that explains how genetic predisposition and cultural learning can lead to the implementation of metacontrol defaults, which however can be shifted towards persistence or flexibility by situational factors. Copyright © 2017 Elsevier Ltd. All rights reserved.

A double-blind, placebo-controlled, glutamine-supplementation trial in growth-faltering Gambian infants.

PubMed

Williams, Elizabeth A; Elia, Marinos; Lunn, Peter G

2007-08-01

Growth faltering during infancy is a characteristic of life in developing countries. Previous studies have shown that small-intestine mucosal enteropathy, accompanied by endotoxemia and a persistent systemic inflammatory response, accounts for up to 64% of the growth faltering in Gambian infants. The objective was to test whether glutamine, with its putative trophic effects on enterocytes, immune cells, and intestinal integrity, can accelerate the repair of the intestine, lower immunostimulation, and reduce growth faltering. Ninety-three infants aged 4-10 mo from the West Kiang region of The Gambia were studied in a double-blind, double-placebo, controlled trial. Glutamine (0.25 mg/kg body wt) or a placebo that contained an isonitrogenous, isoenergetic mix of nonessential amino acids was orally administered twice daily throughout the 5-mo rainy season. Anthropometric measurements were made monthly during the supplementation period and for 6 mo after supplementation. Intestinal permeability was measured monthly (by determining the ratio of lactulose to mannitol), and finger-prick blood samples were collected for the analysis of plasma proteins on 3 occasions. Gambian infants showed a seasonal deterioration in growth and persistently elevated acute phase protein concentrations and intestinal permeability. Oral supplementation with glutamine did not improve growth (x +/- SE: weight gain, 60 +/- 19 and 69 +/- 20 g/mo; length gain, 1.01 +/- 0.05 and 0.95 +/- 0.03 cm/mo) or intestinal permeability [lactulose:mannitol ratio: 0.29 (95% CI: 0.23, 0.35) and 0.26 (95% CI: 0.21, 0.32)] in the glutamine and placebo groups, respectively. It also had no effect on infant morbidity or on plasma concentrations of immunoglobulins or acute phase proteins. Glutamine supplementation failed to improve growth or intestinal status in malnourished Gambian infants.

Different evolutionary trajectories of vaccine-controlled and non-controlled avian infectious bronchitis viruses in commercial poultry

PubMed Central

Lee, Dong-Hun

2017-01-01

To determine the genetic and epidemiological relationship of infectious bronchitis virus (IBV) isolates from commercial poultry to attenuated live IBV vaccines we conducted a phylogenetic network analysis on the full-length S1 sequence for Arkansas (Ark), Massachusetts (Mass) and Delmarva/1639 (DMV/1639) type viruses isolated in 2015 from clinical cases by 3 different diagnostic laboratories. Phylogenetic network analysis of Ark isolates showed two predominant groups linked by 2 mutations, consistent with subpopulations found in commercial vaccines for this IBV type. In addition, a number of satellite groups surrounding the two predominant populations were observed for the Ark type virus, which is likely due to mutations associated with the nature of this vaccine to persist in flocks. The phylogenetic network analysis of Mass-type viruses shows two groupings corresponding to different manufacturers vaccine sequences. No satellite groups were observed for Mass-type viruses, which is consistent with no persistence of this vaccine type in the field. At the time of collection, no vaccine was being used for the DMV/1639 type viruses and phylogenetic network analysis showed a dispersed network suggesting no clear change in genetic distribution. Selection pressure analysis showed that the DMV/1639 and Mass-type strains were evolving under negative selection, whereas the Ark type viruses had evolved under positive selection. This data supports the hypothesis that live attenuated vaccine usage does play a role in the genetic profile of similar IB viruses in the field and phylogenetic network analysis can be used to identify vaccine and vaccine origin isolates, which is important for our understanding of the role live vaccines play in the evolutionary trajectory of those viruses. PMID:28472110

X-Ray Laser Program Final Report for FY92

DTIC Science & Technology

1993-07-01

also produced population inversion. Ultra- intense , femtosecond- pulsed laboratory lasers ranging from the ultraviolet to the infrared represent an...with pulse lengths of 650 femtoseconds normally Incident on a 2p. thick planar aluminum slab. Comparisons are made for two laser Intensities , two...prepulse is subsequently irradiated by the main high intensity pulse . The persistence of the heliumlike ground state raises the possibility that a photon

Persistence of asymmetry in nonaxisymmetric entry flow in a circular cylindrical tube and its relevance to arterial pulse wave diagnosis.

PubMed

Xue, H; Fung, Y C

1989-02-01

In an experiment motivated by the study of arterial blood flow along the lines suggested by the traditional Chinese medicine, the flow in a pipe whose lumen was blocked by a semi-circular plug two tube-diameters long was visualized by suspended particles, recorded by cinematography, and analyzed digitally. The Reynolds number was in the range of 100 to 450 based on the pipe diameter, similar to that of blood flow in the radial artery in the arms of man. The blockage was found to have a profound effect on the velocity profile of the flow in the wake, but it had little influence on the symmetry of the velocity profile upstream of the block, except in its immediate neighborhood. When the end conditions far away from the block were steady, the flow in the wake was steady. The asymmetry of the flow in the wake can be judged by the deviation of the location of the maximum axial velocity from the center line of the pipe as seen in the plane of symmetry of the blockage. Our results show that the deviation can be described as the sum of two components. The first is a strong one which decays exponentially in an entry length which is about twice as long as the classical Boussinesq entry length of axisymmetric flow. The second is a weaker component which is wavy spatially and persists far downstream (many times the entry length). The separated flow and vortex system behind the blockage are sensitive to the flow rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular Structure and Equilibrium Forces of Bovine Submaxillary Mucin Adsorbed at a Solid-Liquid Interface.

PubMed

Zappone, Bruno; Patil, Navinkumar J; Madsen, Jan B; Pakkanen, Kirsi I; Lee, Seunghwan

2015-04-21

By combining dynamic light scattering, circular dichroism spectroscopy, atomic force microscopy, and surface force apparatus, the conformation of bovine submaxillary mucin in dilute solution and nanomechanical properties of mucin layers adsorbed on mica have been investigated. The samples were prepared by additional chromatographic purification of commercially available products. The mucin molecule was found to have a z-average hydrodynamic diameter of ca. 35 nm in phosphate buffered solution, without any particular secondary or tertiary structure. The contour length of the mucin is larger than, yet of the same order of magnitude as the diameter, indicating that the molecule can be modeled as a relatively rigid polymeric chain due to the large persistence length of the central glycosylated domain. Mucin molecules adsorbed abundantly onto mica from saline buffer, generating polymer-like, long-ranged, repulsive, and nonhysteretic forces upon compression of the adsorbed layers. Detailed analysis of such forces suggests that adsorbed mucins had an elongated conformation favored by the stiffness of the central domain. Acidification of aqueous media was chosen as means to reduce mucin-mucin and mucin-substrate electrostatic interactions. The hydrodynamic diameter in solution did not significantly change when the pH was lowered, showing that the large persistence length of the mucin molecule is due to steric hindrance between sugar chains, rather than electrostatic interactions. Remarkably, the force generated by an adsorbed layer with a fixed surface coverage also remained unaltered upon acidification. This observation can be linked to the surface-protective, pH-resistant role of bovine submaxillary mucin in the variable environmental conditions of the oral cavity.

β -Cyclodextrin polymer binding to DNA: Modulating the physicochemical parameters

NASA Astrophysics Data System (ADS)

Rocha, J. C. B.; Silva, E. F.; Oliveira, M. F.; Sousa, F. B.; Teixeira, A. V. N. C.; Rocha, M. S.

2017-05-01

Cyclodextrins and cyclodextrins-modified molecules have interesting and appealing properties due to their capacity to host components that are normally insoluble or poorly soluble in water. In this work, we investigate the interaction of a β -cyclodextrin polymer (poly-β -CD) with λ -DNA. The polymers are obtained by the reaction of β -CD with epichlorohydrin in alkaline conditions. We have used optical tweezers to characterize the changes of the mechanical properties of DNA molecules by increasing the concentration of poly-β -CD in the sample. The physical chemistry of the interaction is then deduced from these measurements by using a recently developed quenched-disorder statistical model. It is shown that the contour length of the DNA does not change in the whole range of poly-β -CD concentration (<300 μ M ). On the other hand, significant alterations were observed in the persistence length that identifies two binding modes corresponding to the clustering of ˜2.6 and ˜14 polymer molecules along the DNA double helix, depending on the polymer concentration. Comparing these results with the ones obtained for monomeric β -CD, it was observed that the concentration of CD that alters the DNA persistence length is considerably smaller when in the polymeric form. Also, the binding constant of the polymer-DNA interaction is three orders of magnitude higher than the one found for native (monomeric) β -CD. These results show that the polymerization of the β -CD strongly increases its binding affinity to the DNA molecule. This property can be wisely used to modulate the binding of cyclodextrins to the DNA double helix.

Proline-Rich Salivary Proteins Have Extended Conformations

PubMed Central

Boze, Hélène; Marlin, Thérèse; Durand, Dominique; Pérez, Javier; Vernhet, Aude; Canon, Francis; Sarni-Manchado, Pascale; Cheynier, Véronique; Cabane, Bernard

2010-01-01

Abstract Three basic proline-rich salivary proteins have been produced through the recombinant route. IB5 is a small basic proline-rich protein that is involved in the binding of plant tannins in the oral cavity. II-1 is a larger protein with a closely related backbone; it is glycosylated, and it is also able to bind plant tannins. II-1ng has the same polypeptidic backbone as II-1, but it is not glycosylated. Small angle x-ray scattering experiments on dilute solutions of these proteins confirm that they are intrinsically disordered. IB5 and II-1ng can be described through a chain model including a persistence length and cross section. The measured radii of gyration (Rg = 27.9 and 41.0 ± 1 Å respectively) and largest distances (rmax = 110 and 155 ± 10 Å respectively) show that their average conformations are rather extended. The length of the statistical segment (twice the persistence length) is b = 30 Å, which is larger than the usual value (18 Å − 20 Å) for unstructured polypeptide chains. These characteristics are presumably related to the presence of polyproline helices within the polypeptidic backbones. For both proteins, the radius of gyration of the chain cross-section is Rc = 2.7 ± 0.2Å. The glycosylated protein II-1 has similar conformations but the presence of large polyoside sidegroups yields the structure of a branched macromolecule with the same hydrophobic backbone and hydrophilic branches. It is proposed that the unusually extended conformations of these proteins in solution facilitate the capture of plant tannins in the oral cavity. PMID:20643086

Effect of day length on germination of seeds collected in Alaska

USGS Publications Warehouse

Densmore, R.V.

1997-01-01

Day length control can effectively limit seed germination to favorable seasons, but this phenomenon has been studied in relatively few wild plants. I tested species from interior Alaska for day length control of germination under controlled conditions, and I also monitored germination phenology in natural habitats. Unstratified and cold-stratified seeds were germinated on short (13 h) and long (22 h) day length and in the dark at constant and alternating temperatures. On long day length, unstratified Ledum decumbens and Saxifraga tricuspidata seeds germinated from 5??C to 20??C, but on short day length few or no seeds germinated at 5??C and 10??C and germination was reduced at higher temperatures. Unstratified seeds of Diapensia lapponica and Chamaedaphne calyculata germinated only at 15??C and 20??C on long day length, and short day length completely inhibited germination. Cold stratification widened the temperature range for germination on both long and short day lengths, but germination was still lower on short than long day length. Germination phenology in natural habitats was consistent with germination in controlled conditions. In these species, short day length and low temperatures interact to inhibit germination in the fall. After overwintering, seeds germinate in the spring at low temperatures and on long day lengths. The inhibitory effect of short day length is not important in the spring because day length is already long at snowmelt.

Effects of hepatitis B virus infection on human sperm chromosomes.

PubMed

Huang, Jian-Min; Huang, Tian-Hua; Qiu, Huan-Ying; Fang, Xiao-Wu; Zhuang, Tian-Gang; Liu, Hong-Xi; Wang, Yong-Hua; Deng, Li-Zhi; Qiu, Jie-Wen

2003-04-01

To evaluate the level of sperm chromosome aberrations in male patients with hepatitis B, and to directly detect whether there are HBV DNA integrations in sperm chromosomes of hepatitis B patients. Sperm chromosomes of 14 tested subjects (5 healthy controls, 9 patients with HBV infection, including 1 with acute hepatitis B, 2 with chronic active hepatitis B, 4 with chronic persistent hepatitis B, 2 chronic HBsAg carriers with no clinical symptoms) were prepared using interspecific in vitro fertilization between zona-free golden hamster ova and human spermatozoa, and the frequencies of aberration spermatozoa were compared between subjects of HBV infection and controls. Fluorescence in situ hybridization (FISH) to sperm chromosome spreads was carried out with biotin-labeled full length HBV DNA probe to detect the specific HBV DNA sequences in the sperm chromosomes. The total frequency of sperm chromosome aberrations in HBV infection group (14.8 %, 33/223) was significantly higher than that in the control group (4.3 %, 5/116). Moreover, the sperm chromosomes in HBV infection patients commonly presented stickiness, clumping, failure to staining, etc, which would affect the analysis of sperm chromosomes. Specific fluorescent signal spots for HBV DNA were seen in sperm chromosomes of one patient with chronic persistent hepatitis. In 9 (9/42) sperm chromosome complements containing fluorescent signal spots, one presented 5 obvious FISH spots, others presented 2 to 4 signals. There was significant difference of fluorescence intensity among the signal spots. The distribution of signal sites among chromosomes was random. HBV infection can bring about mutagenic effects on sperm chromosomes. Integrations of viral DNA into sperm chromosomes which are multisites and nonspecific, can further increase the instability of sperm chromosomes. This study suggested that HBV infection can create extensively hereditary effects by alteration genetic constituent and/or induction chromosome aberrations, as well as the possibility of vertical transmission of HBV via the germ line to the next generation.

Control Systems with Normalized and Covariance Adaptation by Optimal Control Modification

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T. (Inventor); Burken, John J. (Inventor); Hanson, Curtis E. (Inventor)

2016-01-01

Disclosed is a novel adaptive control method and system called optimal control modification with normalization and covariance adjustment. The invention addresses specifically to current challenges with adaptive control in these areas: 1) persistent excitation, 2) complex nonlinear input-output mapping, 3) large inputs and persistent learning, and 4) the lack of stability analysis tools for certification. The invention has been subject to many simulations and flight testing. The results substantiate the effectiveness of the invention and demonstrate the technical feasibility for use in modern aircraft flight control systems.

Memory for syntax despite amnesia.

PubMed

Ferreira, Victor S; Bock, Kathryn; Wilson, Michael P; Cohen, Neal J

2008-09-01

Syntactic persistence is a tendency for speakers to reproduce sentence structures independently of accompanying meanings, words, or sounds. The memory mechanisms behind syntactic persistence are not fully understood. Although some properties of syntactic persistence suggest a role for procedural memory, current evidence suggests that procedural memory (unlike declarative memory) does not maintain the abstract, relational features that are inherent to syntactic structures. In a study evaluating the contribution of procedural memory to syntactic persistence, patients with anterograde amnesia and matched control speakers reproduced prime sentences with different syntactic structures; reproduced 0, 1, 6, or 10 neutral sentences; then spontaneously described pictures that elicited the primed structures; and finally made recognition judgments for the prime sentences. Amnesic and control speakers showed significant and equivalent syntactic persistence, despite the amnesic speakers' profoundly impaired recognition memory for the primes. Thus, syntax is maintained by procedural-memory mechanisms. This result reveals that procedural memory is capable of supporting abstract, relational knowledge.

Persistence of canine distemper virus in the Greater Yellowstone Ecosystem's carnivore community

USGS Publications Warehouse

Almberg, E.S.; Cross, P.C.; Smith, D.W.

2010-01-01

Canine distemper virus (CDV) is an acute, highly immunizing pathogen that should require high densities and large populations of hosts for long-term persistence, yet CDV persists among terrestrial carnivores with small, patchily distributed groups. We used CDV in the Greater Yellowstone ecosystem's (GYE) wolves (Canis lupus) and coyotes (Canis latrans) as a case study for exploring how metapopulation structure, host demographics, and multi-host transmission affect the critical community size and spatial scale required for CDV persistence. We illustrate how host spatial connectivity and demographic turnover interact to affect both local epidemic dynamics, such as the length and variation in inter-epidemic periods, and pathogen persistence using stochastic, spatially explicit susceptible-exposed-infectious-recovered simulation models. Given the apparent absence of other known persistence mechanisms (e.g., a carrier or environmental state, densely populated host, chronic infection, or a vector), we suggest that CDV requires either large spatial scales or multi-host transmission for persistence. Current GYE wolf populations are probably too small to support endemic CDV. Coyotes are a plausible reservoir host, but CDV would still require 50 000-100 000 individuals for moderate persistence (>50% over 10 years), which would equate to an area of 1-3 times the size of the GYE (60000-200000 km2). Coyotes, and carnivores in general, are not uniformly distributed; therefore, this is probably a gross underestimate of the spatial scale of CDV persistence. However, the presence of a second competent host species can greatly increase the probability of long-term CDV persistence at much smaller spatial scales. Although no management of CDV is currently recommended for the GYE, wolf managers in the region should expect periodic but unpredictable CDV-related population declines as often as every 2-5 years. Awareness and monitoring of such outbreaks will allow corresponding adjustments in management activities such as regulated public harvest, creating a smooth transition to state wolf management and conservation after >30 years of being protected by the Endangered Species Act. ?? 2010 by the Ecological Society of America.

Patterns and predictors of ADHD persistence into adulthood: Results from the National Comorbidity Survey Replication

PubMed Central

Kessler, Ronald C.; Adler, Lenard A.; Barkley, Russell; Biederman, Joseph; Conners, C. Keith; Faraone, Stephen V.; Greenhill, Laurence L.; Jaeger, Savina; Secnik, Kristina; Spencer, Thomas; Üstün, T. Bedirhan; Zaslavsky, Alan M.

2010-01-01

BACKGROUND Despite growing interest in adult ADHD, little is known about predictors of persistence of childhood cases into adulthood. METHODS A retrospective assessment of childhood ADHD, childhood risk factors, and a screen for adult ADHD were included in a sample of 3197 18–44 year old respondents in the National Comorbidity Survey Replication (NCS-R). Blinded adult ADHD clinical reappraisal interviews were administered to a sub-sample of respondents. Multiple imputation (MI) was used to estimate adult persistence of childhood ADHD. Logistic regression was used to study retrospectively reported childhood predictors of persistence. Potential predictors included socio-demographics, childhood ADHD severity, childhood adversity, traumatic life experiences, and comorbid DSM-IV child-adolescent disorders (anxiety, mood, impulse-control, and substance disorders). RESULTS 36.3% of respondents with retrospectively assessed childhood ADHD were classified by blinded clinical interviews as meeting DSM-IV criteria for current ADHD. Childhood ADHD severity and childhood treatment significantly predicted persistence. Controlling for severity and excluding treatment, none of the other variables significantly predicted persistence even though they were significantly associated with childhood ADHD. CONCLUSIONS No modifiable risk factors were found for adult persistence of ADHD. Further research, ideally based on prospective general population samples, is needed to search for modifiable determinants of adult persistence of ADHD. PMID:15950019

Controlling Arc Length in Plasma Welding

NASA Technical Reports Server (NTRS)

Iceland, W. F.

1986-01-01

Circuit maintains arc length on irregularly shaped workpieces. Length of plasma arc continuously adjusted by control circuit to maintain commanded value. After pilot arc is established, contactor closed and transfers arc to workpiece. Control circuit then half-wave rectifies ac arc voltage to produce dc control signal proportional to arc length. Circuit added to plasma arc welding machines with few wiring changes. Welds made with circuit cleaner and require less rework than welds made without it. Beads smooth and free of inclusions.

Role of Stress and Smoking as Modifiable Risk Factors for Nonpersistent and Persistent Back Pain in Women.

PubMed

Schmelzer, Amy C; Salt, Elizabeth; Wiggins, Amanda; Crofford, Leslie J; Bush, Heather; Mannino, David M

2016-03-01

The purpose of this study was to examine the association between smoking and stress with nonpersistent and persistent back pain. Participants included 3703 women who took part in the Kentucky Women's Health Registry in 2008 and 2011. Multivariate logistic regression modeling was used to examine whether smoking status and stress levels were predictive of nonpersistent and persistent back pain, controlling for sociodemographic characteristics. Stress level was associated with both nonpersistent and persistent back pain, whereas smoking was associated with only persistent back pain. Current smokers were 1.5 times more likely to report persistent back pain compared with never smokers, controlling for age, race, body mass index, educational attainment, and employment status. Women experiencing large or overwhelming amounts of stress were 1.8 times more likely to have nonpersistent back pain and 1.6 times more likely to report persistent back pain, compared with women experiencing small amounts of stress. This study further substantiates the findings of prior research that describes a significant relationship between back pain, stress, and smoking. Understanding the role of modifiable risk factors (ie, smoking and stress) and their impact on back pain provides an opportunity to offer a comprehensive and tailored treatment plan.

Risk estimates for persistent high-risk human papillomavirus infections as surrogate endpoints of progressive cervical disease critically depend on reference category: analysis of the combined prospective cohort of the New Independent States of the Former Soviet Union and Latin American Screening studies.

PubMed

Syrjänen, K; Shabalova, I; Naud, P; Kozachenko, V; Derchain, S; Zakharchenko, S; Roteli-Martins, C; Nerovjna, R; Longatto-Filho, A; Kljukina, L; Tatti, S; Branovskaja, M; Hammes, L S; Branca, M; Grunjberga, V; Eržen, M; Juschenko, A; Costa, S; Sarian, L; Podistov, J; Syrjänen, S

2011-06-01

To make feasible future clinical trials with new-generation human papillomavirus (HPV) vaccines, novel virological surrogate endpoints of progressive disease have been proposed, including high-risk HPV (HR-HPV) persistence for six months (6M+) or 12 months (12M+). The risk estimates (relative risks [RRs]) of these 'virological endpoints' are influenced by several variables, not yet validated adequately. We compared the impact of three referent groups: (i) HPV-negative, (ii) HPV-transient, (iii) HPV-mixed outcome on the risk estimates for 6M+ or 12M+ HR-HPV persistence as predictors of progressive disease. Generalized estimating equation models were used to estimate the strength of 6M+ and 12M+ HR-HPV persistence with disease progression to squamous intraepithelial lesions (SILs), cervical intraepithelial neoplasia (CIN) grade 1+, CIN2+, CIN/SIL endpoints, comparing three optional reference categories (i)-(iii) in a prospective sub-cohort of 1865 women from the combined New Independent States of the Former Soviet Union (NIS) and Latin American Screening (LAMS) studies cohort (n = 15,301). The RRs of these viral endpoints as predictors of progressive disease are affected by the length of viral persistence (6M+ or 12M+) and the surrogate endpoint (SIL, CIN1, CIN2, CIN/SIL). Most dramatic is the effect of the referent group used in risk estimates, with the HPV-negative referent group giving the highest and most consistent RRs for both 6M+ and 12M+ viral persistence, irrespective of which surrogate is used. In addition to deciding on whether to use 6M+ or 12M+ persistence criteria, and cytological, histological or combined surrogate endpoints, one should adopt the HPV-negative referent group as the gold standard in all future studies using viral persistence as the surrogate endpoint of progressive disease.

Characterization of Foci and Breakthrough Sites During Persistent and Long-Standing Persistent Atrial Fibrillation in Patients: Studies Using High-Density (510-512 Electrodes) Biatrial Epicardial Mapping.

PubMed

Lee, Seungyup; Sahadevan, Jayakumar; Khrestian, Celeen M; Markowitz, Alan; Waldo, Albert L

2017-03-17

We previously demonstrated that persistent and long-standing persistent atrial fibrillation is maintained by activation emanating from foci and breakthrough sites of different cycle lengths (CLs). The purpose of this study was to characterize the behavior of focal and nonrandom breakthrough activation identified during high-density mapping of atrial fibrillation in these patients. During open heart surgery, we recorded activation from both atria simultaneously using 510 to 512 epicardial electrodes along with ECG lead II in 12 patients with persistent and long-standing persistent atrial fibrillation. For each patient, analysis of 32 consecutive seconds of activation from identified focal (sustained and/or intermittent) and nonrandom breakthrough sites was performed. Multiple foci (sustained and/or intermittent) of different CLs were present in both atria in 11 of 12 patients; 8 foci were sustained, and 22 were intermittent. Temporal CL behavior of sustained foci varied over time (≤20 ms of the mean CL). For intermittent foci, no activation periods were due to a spontaneous pause (18 of 22) or activation of the focus by another wave front (11 of 22). All patients had breakthrough activation. Seven patients had 12 nonrandom breakthrough sites. Periods of no breakthrough activation were caused by a spontaneous pause (6 of 12 patients) or activation from another wave front (4 of 12) or were uncertain (5 of 12). Focal and nonrandom breakthrough activation sometimes produced repetitive "wannabe" (incomplete) reentry in 6 of 12 patients. During persistent and long-standing persistent atrial fibrillation, sustained foci manifested variable CLs. Spontaneous pauses or activation from other wave fronts explained the intermittency of foci and nonrandom breakthrough. Focal and nonrandom breakthrough activation occasionally produced wannabe reentry. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Differences in placental telomere length suggest a link between racial disparities in birth outcomes and cellular aging.

PubMed

Jones, Christopher W; Gambala, Cecilia; Esteves, Kyle C; Wallace, Maeve; Schlesinger, Reid; O'Quinn, Marguerite; Kidd, Laura; Theall, Katherine P; Drury, Stacy S

2017-03-01

Health disparities begin early in life and persist across the life course. Despite current efforts, black women exhibit greater risk for pregnancy complications and negative perinatal outcomes compared with white women. The placenta, which is a complex multi-tissue organ, serves as the primary transducer of bidirectional information between the mother and fetus. Altered placental function is linked to multiple racially disparate pregnancy complications; however, little is known about racial differences in molecular factors within the placenta. Several pregnancy complications, which include preeclampsia and fetal growth restriction, exhibit racial disparities and are associated with shorter placental telomere length, which is an indicator of cellular stress and aging. Cellular senescence and telomere dynamics are linked to the molecular mechanisms that are associated with the onset of labor and parturition. Further, racial differences in telomere length are found in a range of different peripheral tissues. Together these factors suggest that exploration of racial differences in telomere length of the placenta may provide novel mechanistic insight into racial disparities in birth outcomes. This study examined whether telomere length measured in 4 distinct fetally derived tissues were significantly different between black and white women. The study had 2 hypotheses: (1) that telomere length that is measured in different placental tissue types would be correlated and (2) that across all sampled tissues telomere length would differ by race. In a prospective study, placental tissue samples were collected from the amnion, chorion, villus, and umbilical cord from black and white singleton pregnancies (N=46). Telomere length was determined with the use of monochrome multiplex quantitative real-time polymerase chain reaction in each placental tissue. Demographic and pregnancy-related data were also collected. Descriptive statistics characterized the sample overall and among black and white women separately. The overall impact of race was assessed by multilevel mixed-effects linear regression models that included empirically relevant covariates. Telomere length was correlated significantly across all placental tissues. Pairwise analyses of placental tissue telomere length revealed significantly longer telomere length in the amnion compared with the chorion (t=-2.06; P=.043). Overall telomere length measured in placenta samples from black mothers were significantly shorter than those from white mothers (β=-0.09; P=.04). Controlling for relevant maternal and infant characteristics strengthened the significance of the observed racial differences (β=-0.12; P=.02). Within tissue analyses revealed that the greatest difference by race was found in chorionic telomere length (t=-2.81; P=.007). These findings provide the first evidence of racial differences in placental telomere length. Telomere length was significantly shorter in placental samples from black mothers compared with white mothers. Given previous studies that have reported that telomere length, cellular senescence, and telomere dynamics are molecular factors that contribute to the rupture of the amniotic sac, onset of labor, and parturition, our findings of shorter telomere length in placentas from black mothers suggest that accelerated cellular aging across placental tissues may be relevant to the increased risk of preterm delivery in black pregnancies. Our results suggest that racial differences in cellular aging in the placenta contribute to the earliest roots of health disparities. Copyright © 2016 Elsevier Inc. All rights reserved.

Intermittent hypoxia during recovery from neonatal hyperoxic lung injury causes long-term impairment of alveolar development: A new rat model of BPD.

PubMed

Mankouski, Anastasiya; Kantores, Crystal; Wong, Mathew J; Ivanovska, Julijana; Jain, Amish; Benner, Eric J; Mason, Stanley N; Tanswell, A Keith; Auten, Richard L; Jankov, Robert P

2017-02-01

Bronchopulmonary dysplasia (BPD) is a chronic lung injury characterized by impaired alveologenesis that may persist into adulthood. Rat models of BPD using varying degrees of hyperoxia to produce injury either cause early mortality or spontaneously recover following removal of the inciting stimulus, thus limiting clinical relevance. We sought to refine an established rat model induced by exposure to 60% O 2 from birth by following hyperoxia with intermittent hypoxia (IH). Rats exposed from birth to air or 60% O 2 until day 14 were recovered in air with or without IH (FI O 2 = 0.10 for 10 min every 6 h) until day 28 Animals exposed to 60% O 2 and recovered in air had no evidence of abnormal lung morphology on day 28 or at 10-12 wk. In contrast, 60% O 2 -exposed animals recovered in IH had persistently increased mean chord length, more dysmorphic septal crests, and fewer peripheral arteries. Recovery in IH also increased pulmonary vascular resistance, Fulton index, and arterial wall thickness. IH-mediated abnormalities in lung structure (but not pulmonary hypertension) persisted when reexamined at 10-12 wk, accompanied by increased pulmonary vascular reactivity and decreased exercise tolerance. Increased mean chord length secondary to IH was prevented by treatment with a peroxynitrite decomposition catalyst [5,10,15,20-Tetrakis(4-sulfonatophenyl)-21H,23H-porphyrin iron (III) chloride, 30 mg/kg/day, days 14-28], an effect accompanied by fewer inflammatory cells. We conclude that IH during recovery from hyperoxia-induced injury prevents recovery of alveologenesis and leads to changes in lung and pulmonary vascular function lasting into adulthood, thus more closely mimicking contemporary BPD. Copyright © 2017 the American Physiological Society.

Environmental persistence of a pathogen used in microbial insect control

Treesearch

Karl M. Polivka; Greg Dwyer; Constance J. Mehmel

2017-01-01

We conducted an experimental study of infection, transmission, and persistence of a nucleopolyhedrovirus (NPV) of Douglas-fir tussock moth (Orgyia pseudotsugata) to better understand mechanisms determining the efficacy of the virus when it is used as a microbial control agent. In a field experiment, we quantified infection rates of larvae exposed...

Intervention for Verb Argument Structure in Children with Persistent SLI: A Randomized Control Trial

ERIC Educational Resources Information Center

Ebbels, Susan H.; van der Lely, Heather K. J.; Dockrell, Julie E.

2007-01-01

Purpose: The authors aimed to establish whether 2 theoretically motivated interventions could improve use of verb argument structure in pupils with persistent specific language impairment (SLI). Method: Twenty-seven pupils with SLI (ages 11;0-16;1) participated in this randomized controlled trial with "blind" assessment. Participants were randomly…

Cell-free DNA and telomere length among women undergoing in vitro fertilization treatment.

PubMed

Czamanski-Cohen, J; Sarid, O; Cwikel, J; Douvdevani, A; Levitas, E; Lunenfeld, E; Har-Vardi, I

2015-11-01

The current research is aimed at finding potential non-invasive bio-markers that will help us learn more about the mechanisms at play in failed assisted reproduction treatment. This exploratory pilot study examined the relationship between cell-free DNA (CFD) in plasma and telomere length in lymphocytes among women undergoing in vitro fertilization (IVF) and compared telomere length and CFD levels to a healthy control group. Blood of 20 women undergoing IVF was collected at three time points during the IVF cycle. We assessed the relationship between CFD and telomere length as well as controlling for morning cortisol levels. We also collected blood of 10 healthy controls at two time points (luteal and follicular phases of the menstrual cycle) and compared mean telomere length, CFD, and cortisol levels between the IVF patients and healthy controls. The results revealed an inverse relationship between CFD levels and telomere lengths at several time points that remained significant even after controlling for cortisol levels. Women undergoing IVF had statistically significant higher levels of CFD and shorter telomeres compared to healthy controls. The relationship between telomere length and CFD should be further explored in larger studies in order to uncover potential mechanisms that cause both shortened telomere length and elevated CFD in women undergoing IVF.

Left ventricular mass of persistent masked hypertension in Hong Kong Chinese adolescents: a 4-year follow-up study.

PubMed

Yam, Man-Ching; So, Hung-Kwan; Kwok, Sit-Yee; Lo, Fung-Cheung; Mok, Chi-Fung; Leung, Chuk-Kwan; Yip, Wai-Kwok; Sung, Yn-Tz

2018-06-01

In our previous study, the prevalence of childhood masked hypertension was 11%. This study aims to assess the left ventricular mass index of persistent masked hypertension and determine the factors of elevated left ventricular mass index in Hong Kong Chinese adolescents from a community cohort. Community prospective cohort study, follow-up of a case-control study in community. Patients with masked hypertension at baseline were invited to recheck ambulatory blood pressure for the persistence of masked hypertension. A total of 144 out of 165 patients with masked hypertension in the 2011/2012 ambulatory blood pressure survey consented to participate in the study. In all, 48 patients were found to have persistent masked hypertension by ambulatory blood pressure rechecking and were matched with normotensive controls by sex, age, and body height. The left ventricular mass (117.3±39.9 g versus 87.0±28.2 g versus 102.0±28.2 g) and left ventricular mass index (30.1±8.4 g/m2.7 versus 23.9±6.3 g/m2.7 versus 25.1±5.7 g/m2.7) were significantly higher in the persistent masked hypertension group (p<0.0001) compared with the patients without persistent masked hypertension and controls. In multivariate linear regression analysis, left ventricular mass index was found to be higher in male gender (β=4.874, p<0.0001) and the patients with persistent masked hypertension (β=2.796, p=0.003). In addition, left ventricular mass index was positively associated with body mass index z-score (β=3.045, p<0.0001) and low-density lipoprotein cholesterol concentration (β=1.634, p=0.015). Persistent masked hypertension in adolescents is associated with elevated left ventricular mass index.

Pregnancy Leads to Lasting Changes in Foot Structure

PubMed Central

Segal, Neil A.; Boyer, Elizabeth R.; Teran-Yengle, Patricia; Glass, Natalie; Hillstrom, Howard J.; Yack, H. John

2013-01-01

Objective Women are disproportionately affected by musculoskeletal disorders. Parous women appear to be at particularly elevated risk for structural and functional changes in the lower limbs. The combination of increased weight on joints with potentially greater laxity during pregnancy could lead to permanent structural changes in feet. Although arches may become lax during pregnancy, it is unknown whether changes persist. The objective of this study was to determine whether arch height loss persists postpartum. Design Forty-nine women completed this longitudinal study. Static and dynamic arch measurements were collected in first-trimester and at 19 weeks postpartum. Linear mixed models were used to determine whether outcome measures significantly changed overall or by parity. Results Arch height and rigidity index significantly decreased, with concomitant increases in foot length and arch drop. The first pregnancy accounted for the reduction in arch rigidity and increases in foot length and arch drop. No changes were detected in the center of pressure excursion index. Conclusions Pregnancy appears to be associated with a permanent loss of arch height and the first pregnancy may be the most significant. These changes in the feet could contribute to the increased risk for musculoskeletal disorders in women. Further research should assess the efficacy of rehabilitative interventions for prevention of pregnancy-related arch drop. PMID:23117270

Influence of RNA Strand Rigidity on Polyion Complex Formation with Block Catiomers.

PubMed

Hayashi, Kotaro; Chaya, Hiroyuki; Fukushima, Shigeto; Watanabe, Sumiyo; Takemoto, Hiroyasu; Osada, Kensuke; Nishiyama, Nobuhiro; Miyata, Kanjiro; Kataoka, Kazunori

2016-03-01

Polyion complexes (b-PICs) are prepared by mixing single- or double-stranded oligo RNA (aniomer) with poly(ethylene glycol)-b-poly(L-lysine) (PEG-PLL) (block catiomer) to clarify the effect of aniomer chain rigidity on association behaviors at varying concentrations. Here, a 21-mer single-stranded RNA (ssRNA) (persistence length: 1.0 nm) and a 21-mer double-stranded RNA (small interfering RNA, siRNA) (persistence length: 62 nm) are compared. Both oligo RNAs form a minimal charge-neutralized ionomer pair with a single PEG-PLL chain, termed unit b-PIC (uPIC), at low concentrations (<≈ 0.01 mg mL(-1)). Above the critical association concentration (≈ 0.01 mg mL(-1)), ssRNA b-PICs form secondary associates, PIC micelles, with sizes up to 30-70 nm, while no such multimolecular assembly is observed for siRNA b-PICs. The entropy gain associated with the formation of a segregated PIC phase in the multimolecular PIC micelles may not be large enough for rigid siRNA strands to compensate with appreciably high steric repulsion derived from PEG chains. Chain rigidity appears to be a critical parameter in polyion complex association. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Reinforcement History and Instructions on the Persistence of Student Engagement.

ERIC Educational Resources Information Center

Martens, Brian K.; Bradley, Tracy A.; Eckert, Tanya L.

1997-01-01

This study examined the effects of three reinforcement histories on the persistence of task engagement by two students (ages 9-10) who were off task during independent seat work. Results found the reinforcement history that contained an instructional control component produced the greatest persistence in student engagement. (Author/CR)

Intertwined Effects of Gender and Migration Status on Persistence in SET Study Programmes

ERIC Educational Resources Information Center

Guenther, Elisabeth Anna; Koeszegi, Sabine Theresia

2017-01-01

This paper explores the intersectional interference of gender and migration status on students' persistence at an Austrian University of Technology. While controlling for the pre-university education and performance indicators, we estimate the odds for the persistence of male and female students, as well as of students with diverse migration…

Determining If Phylogenetic Relatedness of Listeria Monocytogenes Isolates Corresponds to Persistence in Poultry Processing Plants Using Whole-Genome Sequencing

USDA-ARS?s Scientific Manuscript database

Introduction: Controlling Listeria monocytogenes on ready-to-eat meat and poultry products and in food processing facilities is challenging. Surveys have found that some L. monocytogenes types are more persistent in processing facilities than others, but the reason is unknown. It is possible persist...

Intertwined effects of gender and migration status on persistence in SET study programmes

NASA Astrophysics Data System (ADS)

Guenther, Elisabeth Anna; Koeszegi, Sabine Theresia

2017-11-01

This paper explores the intersectional interference of gender and migration status on students' persistence at an Austrian University of Technology. While controlling for the pre-university education and performance indicators, we estimate the odds for the persistence of male and female students, as well as of students with diverse migration statuses. We use the enrolment data of students from 1998 to 2010. The analysis reveals remarkable and significant effects of gender and migration status, as well as intersectional interference effects from both social categories on persistence. Female and students with immigration status are less likely to persist, even if performance and previous relevant experiences are controlled. A segregated analysis of the student population sheds further light on the interlocked and entangled effects of the social ascriptions underlying gender and migration status. The analysis supports the proposition of the accumulation of (dis-)advantages along students' careers. The profound quantification of gender and migration status effects can be utilised as basis for further research and purposeful policy measures to increase persistence in Science, Engineering and Technology for students with diverse backgrounds.

Numerical Model for the Study of the Strength and Failure Modes of Rock Containing Non-Persistent Joints

NASA Astrophysics Data System (ADS)

Vergara, Maximiliano R.; Van Sint Jan, Michel; Lorig, Loren

2016-04-01

The mechanical behavior of rock containing parallel non-persistent joint sets was studied using a numerical model. The numerical analysis was performed using the discrete element software UDEC. The use of fictitious joints allowed the inclusion of non-persistent joints in the model domain and simulating the progressive failure due to propagation of existing fractures. The material and joint mechanical parameters used in the model were obtained from experimental results. The results of the numerical model showed good agreement with the strength and failure modes observed in the laboratory. The results showed the large anisotropy in the strength resulting from variation of the joint orientation. Lower strength of the specimens was caused by the coalescence of fractures belonging to parallel joint sets. A correlation was found between geometrical parameters of the joint sets and the contribution of the joint sets strength in the global strength of the specimen. The results suggest that for the same dip angle with respect to the principal stresses; the uniaxial strength depends primarily on the joint spacing and the angle between joints tips and less on the length of the rock bridges (persistency). A relation between joint geometrical parameters was found from which the resulting failure mode can be predicted.

Insights into Persistence Mechanisms of a Zoonotic Virus in Bat Colonies Using a Multispecies Metapopulation Model

PubMed Central

Pons-Salort, Margarita; Serra-Cobo, Jordi; Jay, Flora; López-Roig, Marc; Lavenir, Rachel; Guillemot, Didier; Letort, Véronique; Bourhy, Hervé; Opatowski, Lulla

2014-01-01

Rabies is a worldwide zoonosis resulting from Lyssavirus infection. In Europe, Eptesicus serotinus is the most frequently reported bat species infected with Lyssavirus, and thus considered to be the reservoir of European bat Lyssavirus type 1 (EBLV-1). To date, the role of other bat species in EBLV-1 epidemiology and persistence remains unknown. Here, we built an EBLV-1−transmission model based on local observations of a three-cave and four-bat species (Myotis capaccinii, Myotis myotis, Miniopterus schreibersii, Rhinolophus ferrumequinum) system in the Balearic Islands, for which a 1995–2011 serological dataset indicated the continuous presence of EBLV-1. Eptesicus serotinus was never observed in the system during the 16-year follow-up and therefore was not included in the model. We used the model to explore virus persistence mechanisms and to assess the importance of each bat species in the transmission dynamics. We found that EBLV-1 could not be sustained if transmission between M. schreibersii and other bat species was eliminated, suggesting that this species serves as a regional reservoir. Global sensitivity analysis using Sobol's method revealed that following the rate of autumn−winter infectious contacts, M. schreibersii's incubation- and immune-period durations, but not the infectious period length, were the most relevant factors driving virus persistence. PMID:24755619

Epigenetic differentiation persists after male gametogenesis in natural populations of the perennial herb Helleborus foetidus (Ranunculaceae).

PubMed

Herrera, Carlos M; Medrano, Mónica; Bazaga, Pilar

2013-01-01

Despite the importance of assessing the stability of epigenetic variation in non-model organisms living in real-world scenarios, no studies have been conducted on the transgenerational persistence of epigenetic structure in wild plant populations. This gap in knowledge is hindering progress in the interpretation of natural epigenetic variation. By applying the methylation-sensitive amplified fragment length polymorphism (MSAP) technique to paired plant-pollen (i.e., sporophyte-male gametophyte) DNA samples, and then comparing methylation patterns and epigenetic population differentiation in sporophytes and their descendant gametophytes, we investigated transgenerational constancy of epigenetic structure in three populations of the perennial herb Helleborus foetidus (Ranunculaceae). Single-locus and multilocus analyses revealed extensive epigenetic differentiation between sporophyte populations. Locus-by-locus comparisons of methylation status in individual sporophytes and descendant gametophytes showed that ~75% of epigenetic markers persisted unchanged through gametogenesis. In spite of some epigenetic reorganization taking place during gametogenesis, multilocus epigenetic differentiation between sporophyte populations was preserved in the subsequent gametophyte stage. In addition to illustrating the efficacy of applying the MSAP technique to paired plant-pollen DNA samples to investigate epigenetic gametic inheritance in wild plants, this paper suggests that epigenetic differentiation between adult plant populations of H. foetidus is likely to persist across generations.

Epigenetic Differentiation Persists after Male Gametogenesis in Natural Populations of the Perennial Herb Helleborus foetidus (Ranunculaceae)

PubMed Central

Herrera, Carlos M.; Medrano, Mónica; Bazaga, Pilar

2013-01-01

Despite the importance of assessing the stability of epigenetic variation in non-model organisms living in real-world scenarios, no studies have been conducted on the transgenerational persistence of epigenetic structure in wild plant populations. This gap in knowledge is hindering progress in the interpretation of natural epigenetic variation. By applying the methylation-sensitive amplified fragment length polymorphism (MSAP) technique to paired plant-pollen (i.e., sporophyte-male gametophyte) DNA samples, and then comparing methylation patterns and epigenetic population differentiation in sporophytes and their descendant gametophytes, we investigated transgenerational constancy of epigenetic structure in three populations of the perennial herb Helleborus foetidus (Ranunculaceae). Single-locus and multilocus analyses revealed extensive epigenetic differentiation between sporophyte populations. Locus-by-locus comparisons of methylation status in individual sporophytes and descendant gametophytes showed that ∼75% of epigenetic markers persisted unchanged through gametogenesis. In spite of some epigenetic reorganization taking place during gametogenesis, multilocus epigenetic differentiation between sporophyte populations was preserved in the subsequent gametophyte stage. In addition to illustrating the efficacy of applying the MSAP technique to paired plant-pollen DNA samples to investigate epigenetic gametic inheritance in wild plants, this paper suggests that epigenetic differentiation between adult plant populations of H. foetidus is likely to persist across generations. PMID:23936245

Length of stay for older adults residing in nursing homes at the end of life.

PubMed

Kelly, Anne; Conell-Price, Jessamyn; Covinsky, Kenneth; Cenzer, Irena Stijacic; Chang, Anna; Boscardin, W John; Smith, Alexander K

2010-09-01

To describe lengths of stay of nursing home decedents. Retrospective cohort study. The Health and Retirement Study (HRS), a nationally representative survey of U.S. adults aged 50 and older. One thousand eight hundred seventeen nursing home residents who died between 1992 and 2006. The primary outcome was length of stay, defined as the number of months between nursing home admission and date of death. Covariates were demographic, social, and clinical factors drawn from the HRS interview conducted closest to the date of nursing home admission. The mean age of decedents was 83.3 ± 9.0; 59.1% were female, and 81.5% were white. Median and mean length of stay before death were 5 months (interquartile range 1-20) and 13.7 ± 18.4 months, respectively. Fifty-three percent died within 6 months of placement. Large differences in median length of stay were observed according to sex (men, 3 months vs women, 8 months) and net worth (highest quartile, 3 months vs lowest quartile, 9 months) (all P <.001). These differences persisted after adjustment for age, sex, marital status, net worth, geographic region, and diagnosed chronic conditions (cancer, hypertension, diabetes mellitus, lung disease, heart disease, and stroke). Nursing home lengths of stay are brief for the majority of decedents. Lengths of stay varied markedly according to factors related to social support. © 2010, Copyright the Authors. Journal compilation © 2010, The American Geriatrics Society.

Relationship of the length of the first stage of labor to the length of the second stage.

PubMed

Nelson, David B; McIntire, Donald D; Leveno, Kenneth J

2013-07-01

To evaluate the relationship between the lengths of the first and second stages of labor. In this observational study of women delivering at our hospital, the onset of the first stage of labor was defined as admission at 3-cm to 4-cm dilatation in the presence of uterine contractions with or without rupture of membranes. This study was limited to nulliparous women with a singleton, cephalic live birth at 37 0/7 weeks of gestation or more. Women presenting with more advanced cervical dilatation (greater than 4 cm), prior cesarean delivery, diabetes, hypertension, and placental accidents were excluded. Each woman was analyzed based on her specific lengths of first and second stages of labor, that is, paired observations for each woman. Between January 1, 2001, and June 30, 2012, a total of 172,522 women were delivered and 12,523 (7.3%) met the inclusion criteria. The 95 percentile was 15.6 and 2.9 hours for the first and second stages, respectively. Women with first stages greater than the 95 percentile had a 16.3% rate of a second-stage length greater than the 95 percentile compared with 4.5% (P<.001) in women with first stages less than the 95 percentile. This relationship persisted when analyzed for variables influencing labor to include neonate birth weight, epidural analgesia, or maternal size. Overall, the length of the second stage significantly increased concomitantly with increasing length of the first stage (P<.001). II.

Cognitive and neurophysiological markers of ADHD persistence and remission.

PubMed

Cheung, Celeste H M; Rijsdijk, Fruhling; McLoughlin, Gráinne; Brandeis, Daniel; Banaschewski, Tobias; Asherson, Philip; Kuntsi, Jonna

2016-06-01

Attention-deficit hyperactivity disorder (ADHD) persists in around two-thirds of individuals in adolescence and early adulthood. To examine the cognitive and neurophysiological processes underlying the persistence or remission of ADHD. Follow-up data were obtained from 110 young people with childhood ADHD and 169 controls on cognitive, electroencephalogram frequency, event-related potential (ERP) and actigraph movement measures after 6 years. ADHD persisters differed from remitters on preparation-vigilance measures (contingent negative variation, delta activity, reaction time variability and omission errors), IQ and actigraph count, but not on executive control measures of inhibition or working memory (nogo-P3 amplitudes, commission errors and digit span backwards). Preparation-vigilance measures were markers of remission, improving concurrently with ADHD symptoms, whereas executive control measures were not sensitive to ADHD persistence/remission. For IQ, the present and previous results combined suggest a role in moderating ADHD outcome. These findings fit with previously identified aetiological separation of the cognitive impairments in ADHD. The strongest candidates for the development of non-pharmacological interventions involving cognitive training and neurofeedback are the preparation-vigilance processes that were markers of ADHD remission. © The Royal College of Psychiatrists 2016.

Doppler color imaging. Principles and instrumentation.

PubMed

Kremkau, F W

1992-01-01

DCI acquires Doppler-shifted echoes from a cross-section of tissue scanned by an ultrasound beam. These echoes are then presented in color and superimposed on the gray-scale anatomic image of non-Doppler-shifted echoes received during the scan. The flow echoes are assigned colors according to the color map chosen. Usually red, yellow, or white indicates positive Doppler shifts (approaching flow) and blue, cyan, or white indicates negative shifts (receding flow). Green is added to indicate variance (disturbed or turbulent flow). Several pulses (the number is called the ensemble length) are needed to generate a color scan line. Linear, convex, phased, and annular arrays are used to acquire the gray-scale and color-flow information. Doppler color-flow instruments are pulsed-Doppler instruments and are subject to the same limitations, such as Doppler angle dependence and aliasing, as other Doppler instruments. Color controls include gain, TGC, map selection, variance on/off, persistence, ensemble length, color/gray priority. Nyquist limit (PRF), baseline shift, wall filter, and color window angle, location, and size. Doppler color-flow instruments generally have output intensities intermediate between those of gray-scale imaging and pulsed-Doppler duplex instruments. Although there is no known risk with the use of color-flow instruments, prudent practice dictates that they be used for medical indications and with the minimum exposure time and instrument output required to obtain the needed diagnostic information.

Anesthetic Sevoflurane Causes Rho-Dependent Filopodial Shortening in Mouse Neurons.

PubMed

Zimering, Jeffrey H; Dong, Yuanlin; Fang, Fang; Huang, Lining; Zhang, Yiying; Xie, Zhongcong

2016-01-01

Early postnatal anesthesia causes long-lasting learning and memory impairment in rodents, however, evidence for a specific neurotoxic effect on early synaptogenesis has not been demonstrated. Drebrin A is an actin binding protein whose localization in dendritic protrusions serves an important role in dendritic spine morphogenesis, and is a marker for early synaptogenesis. We therefore set out to investigate whether clinically-relevant concentrations of anesthetic sevoflurane, widely- used in infants and children, alters dendritic morphology in cultured fetal day 16 mouse hippocampal neurons. After 7 days in vitro, mouse hippocampal neurons were exposed to four hours of 3% sevoflurane in 95% air/5% CO2 or control condition (95% air/5% CO2). Neurons were fixed in 4% paraformaldehyde and stained with Alexa Fluor555-Phalloidin, and/or rabbit anti-mouse drebrin A/E antibodies which permitted subcellular localization of filamentous (F)-actin and/or drebrin immunoreactivity, respectively. Sevoflurane caused acute significant length-shortening in filopodia and thin dendritic spines in days-in-vitro 7 neurons, an effect which was completely rescued by co-incubating neurons with ten micromolar concentrations of the selective Rho kinase inhibitor Y27632. Filopodia and thin spine recovered in length two days after sevoflurane exposure. Yet cluster-type filopodia (a precursor to synaptic filopodia) were persistently significantly decreased in number on day-in-vitro 9, in part owing to preferential localization of drebrin immunoreactivity to dendritic shafts versus filopodial stalks. These data suggest that sevoflurane induces F-actin depolymerization leading to acute, reversible length-shortening in dendritic protrusions through a mechanism involving (in part) activation of RhoA/Rho kinase signaling and impairs localization of drebrin A to filopodia required for early excitatory synapse formation.

Focal Length Controllable Ultrasonic Transducer Using Bimorph-Type Bending Actuator

NASA Astrophysics Data System (ADS)

Chae, Min-Ku; Kim, Moo-Joon; Ha, Kang-Lyeol; Lee, Chai-Bong

2003-05-01

Using a bimorph-type bending actuator, we propose a new method for controlling the focal length of a transducer by electric DC voltage. We designed two focal length controllable ultrasonic transducers with actuators, a line-focus and a point-focus transducer. The polyvinylidene fluoride (PVDF) piezoelectric type polymer film is used for transmitting and receiving of ultrasonic signals. Using the new method, it is confirmed by investigation of the underwater acoustic field that the focal length can be controlled to within 10% of the radius of the transducer curvature.

Automatic Control Of Length Of Welding Arc

NASA Technical Reports Server (NTRS)

Iceland, William F.

1991-01-01

Nonlinear relationships among current, voltage, and length stored in electronic memory. Conceptual microprocessor-based control subsystem maintains constant length of welding arc in gas/tungsten arc-welding system, even when welding current varied. Uses feedback of current and voltage from welding arc. Directs motor to set position of torch according to previously measured relationships among current, voltage, and length of arc. Signal paths marked "calibration" or "welding" used during those processes only. Other signal paths used during both processes. Control subsystem added to existing manual or automatic welding system equipped with automatic voltage control.

Biomarkers in Persistent AF and Heart Failure: Impact of Catheter Ablation Compared with Rate Control.

PubMed

Jones, David G; Haldar, Shouvik K; Donovan, Jacqueline; McDonagh, Theresa A; Sharma, Rakesh; Hussain, Wajid; Markides, Vias; Wong, Tom

2016-09-01

To investigate the effects of catheter ablation and rate control strategies on cardiac and inflammatory biomarkers in patients with heart failure and persistent atrial fibrillation (AF). Patients were recruited from the ARC-HF trial (catheter Ablation vs Rate Control for management of persistent AF in Heart Failure, NCT00878384), which compared ablation with rate control for persistent AF in heart failure. B-type natriuretic peptide (BNP), midregional proatrial natriuretic peptide (MR-proANP), apelin, and interleukin-6 (IL-6) were assayed at baseline, 3 months, 6 months, and 12 months. The primary end point, analyzed per-protocol, was changed from baseline at 12 months. Of 52 recruited patients, 24 ablation and 25 rate control subjects were followed to 12 months. After 1.2 ± 0.5 procedures, sinus rhythm was present in 22 (92%) ablation patients; under rate control, rate criteria were achieved in 23 (96%) of 24 patients remaining in AF. At 12 months, MR-proANP fell significantly in the ablation arm (-106.0 pmol/L, interquartile range [IQR] -228.2 to -60.6) compared with rate control (-28.7 pmol/L, IQR -69 to +9.5, P = 0.028). BNP showed a similar trend toward reduction (P = 0.051), with no significant difference in apelin (P = 0.13) or IL-6 (P = 0.68). Changes in MR-proANP and BNP correlated with peak VO2 and ejection fraction, and MR-proANP additionally with quality-of-life score. Catheter ablation, compared with rate control, in patients with heart failure and persistent AF was associated with significant reduction in MR-proANP, which correlated with physiological and symptomatic improvement. Ablation-based rhythm control may induce beneficial cardiac remodeling, unrelated to changes in inflammatory state. This may have prognostic implications, which require confirmation by event end point studies. © 2016 Wiley Periodicals, Inc.

Blockade of interferon Beta, but not interferon alpha, signaling controls persistent viral infection.

PubMed

Ng, Cherie T; Sullivan, Brian M; Teijaro, John R; Lee, Andrew M; Welch, Megan; Rice, Stephanie; Sheehan, Kathleen C F; Schreiber, Robert D; Oldstone, Michael B A

2015-05-13

Although type I interferon (IFN-I) is thought to be beneficial against microbial infections, persistent viral infections are characterized by high interferon signatures suggesting that IFN-I signaling may promote disease pathogenesis. During persistent lymphocytic choriomeningitis virus (LCMV) infection, IFNα and IFNβ are highly induced early after infection, and blocking IFN-I receptor (IFNAR) signaling promotes virus clearance. We assessed the specific roles of IFNβ versus IFNα in controlling LCMV infection. While blockade of IFNβ alone does not alter early viral dissemination, it is important in determining lymphoid structure, lymphocyte migration, and anti-viral T cell responses that lead to accelerated virus clearance, approximating what occurs during attenuation of IFNAR signaling. Comparatively, blockade of IFNα was not associated with improved viral control, but with early dissemination of virus. Thus, despite their use of the same receptor, IFNβ and IFNα have unique and distinguishable biologic functions, with IFNβ being mainly responsible for promoting viral persistence. Copyright © 2015 Elsevier Inc. All rights reserved.

Intelligence and Persisting with Medication for Two Years: Analysis in a Randomised Controlled Trial

ERIC Educational Resources Information Center

Deary, Ian J.; Gale, Catharine R.; Stewart, Marlene C. W.; Fowkes, F. Gerald R.; Murray, Gordon D.; Batty, G. David; Price, Jacqueline F.

2009-01-01

The study examined whether verbal intelligence is associated with persisting to take medication for up to two years. The design is a prospective follow-up of compliance with taking medication in high-risk individuals participating in a randomised, placebo-controlled trial set in Central Scotland. Participants were 1993 people aged between 50 and…

Predicting stability and change in loneliness in later life

PubMed Central

Newall, Nancy E. G.; Chipperfield, Judith G.; Bailis, Daniel S.

2016-01-01

This study examined potential discriminators of groups of older adults showing different patterns of stability or change in loneliness over 5 years: those who became lonely, overcame loneliness, were persistently lonely, and were persistently not lonely. Discriminant function analysis results showed that the persistently lonely, compared with the persistently not lonely, were more often living alone, widowed, and experiencing poorer health and perceived control. Moreover, changes in living arrangements and perceived control predicted loneliness change. In conclusion, perceiving that one is able to meet social needs is a predictor of loneliness and loneliness change and appears to be more important than people’s friendships. Because the predictors were better able to predict entry into loneliness, results point to the promise of prevention approaches to loneliness interventions. PMID:27867246

Motivating learning, performance, and persistence: the synergistic effects of intrinsic goal contents and autonomy-supportive contexts.

PubMed

Vansteenkiste, Maarten; Simons, Joke; Lens, Willy; Sheldon, Kennon M; Deci, Edward L

2004-08-01

Three field experiments with high school and college students tested the self-determination theory hypotheses that intrinsic (vs. extrinsic) goals and autonomy-supportive (vs. controlling) learning climates would improve students' learning, performance, and persistence. The learning of text material or physical exercises was framed in terms of intrinsic (community, personal growth, health) versus extrinsic (money, image) goals, which were presented in an autonomy-supportive versus controlling manner. Analyses of variance confirmed that both experimentally manipulated variables yielded main effects on depth of processing, test performance, and persistence (all ps <.001), and an interaction resulted in synergistically high deep processing and test performance (but not persistence) when both intrinsic goals and autonomy support were present. Effects were significantly mediated by autonomous motivation.

Evidence of Local Persistence of Human Anthrax in the Country of Georgia Associated with Environmental and Anthropogenic Factors

PubMed Central

Kracalik, Ian T.; Malania, Lile; Tsertsvadze, Nikoloz; Manvelyan, Julietta; Bakanidze, Lela; Imnadze, Paata; Tsanava, Shota; Blackburn, Jason K.

2013-01-01

Background Anthrax is a soil-borne disease caused by the bacterium Bacillus anthracis and is considered a neglected zoonosis. In the country of Georgia, recent reports have indicated an increase in the incidence of human anthrax. Identifying sub-national areas of increased risk may help direct appropriate public health control measures. The purpose of this study was to evaluate the spatial distribution of human anthrax and identify environmental/anthropogenic factors associated with persistent clusters. Methods/Findings A database of human cutaneous anthrax in Georgia during the period 2000–2009 was constructed using a geographic information system (GIS) with case data recorded to the community location. The spatial scan statistic was used to identify persistence of human cutaneous anthrax. Risk factors related to clusters of persistence were modeled using a multivariate logistic regression. Areas of persistence were identified in the southeastern part of the country. Results indicated that the persistence of human cutaneous anthrax showed a strong positive association with soil pH and urban areas. Conclusions/Significance Anthrax represents a persistent threat to public and veterinary health in Georgia. The findings here showed that the local level heterogeneity in the persistence of human cutaneous anthrax necessitates directed interventions to mitigate the disease. High risk areas identified in this study can be targeted for public health control measures such as farmer education and livestock vaccination campaigns. PMID:24040426

QTL mapping and candidate gene analysis of telomere length control factors in maize (Zea mays L.)

USDA-ARS?s Scientific Manuscript database

Telomere length is under genetic control and important for essential telomere functions. Failure to regulate telomere length homeostasis contributes to cancers and aging-related diseases in animals, but the effects of telomere length defects in plants remains poorly understood. To learn more about t...

Transfer matrix approach to the persistent current in quantum rings: Application to hybrid normal-superconducting rings

NASA Astrophysics Data System (ADS)

Nava, Andrea; Giuliano, Rosa; Campagnano, Gabriele; Giuliano, Domenico

2016-11-01

Using the properties of the transfer matrix of one-dimensional quantum mechanical systems, we derive an exact formula for the persistent current across a quantum mechanical ring pierced by a magnetic flux Φ as a single integral of a known function of the system's parameters. Our approach provides exact results at zero temperature, which can be readily extended to a finite temperature T . We apply our technique to exactly compute the persistent current through p -wave and s -wave superconducting-normal hybrid rings, deriving full plots of the current as a function of the applied flux at various system's scales. Doing so, we recover at once a number of effects such as the crossover in the current periodicity on increasing the size of the ring and the signature of the topological phase transition in the p -wave case. In the limit of a large ring size, resorting to a systematic expansion in inverse powers of the ring length, we derive exact analytic closed-form formulas, applicable to a number of cases of physical interest.

Shear Strength and Cracking Process of Non-persistent Jointed Rocks: An Extensive Experimental Investigation

NASA Astrophysics Data System (ADS)

Asadizadeh, Mostafa; Moosavi, Mahdi; Hossaini, Mohammad Farouq; Masoumi, Hossein

2018-02-01

In this paper, a number of artificial rock specimens with two parallel (stepped and coplanar) non-persistent joints were subjected to direct shearing. The effects of bridge length ( L), bridge angle ( γ), joint roughness coefficient (JRC) and normal stress ( σ n) on shear strength and cracking process of non-persistent jointed rock were studied extensively. The experimental program was designed based on Taguchi method, and the validity of the resulting data was assessed using analysis of variance. The results revealed that σ n and γ have the maximum and minimum effects on shear strength, respectively. Also, increase in L from 10 to 60 mm led to decrease in shear strength where high level of JRC profile and σ n led to the initiation of tensile cracks due to asperity interlocking. Such tensile cracks are known as "interlocking cracks" which normally initiate from the asperity and then propagate toward the specimen boundaries. Finally, the cracking process of specimens was classified into three categories, namely tensile cracking, shear cracking and combination of tension and shear or mixed mode tensile-shear cracking.

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

Larsson, P.; Okla, L.; Collvin, L.

Levels of persistent pollutants, including PCBs, [Sigma]DDT, and [gamma]-hexachlorocyclohexane, were examined in a pike population inhabiting a eutrophic lake in southern Scandinavia. For females, levels of persistent pollutants decreased linearly with age, weight, or length. This decline was ascribed to the seasonal elimination of the lipophilic pollutants in roe, which contained up to 10 times higher fat levels compared to muscle and over 10 times the amounts of pollutants. Male pike contained higher levels of pollutants than females, probably due to the lower elimination via gonadal products, as germinal tissue constitutes only 2% of the male total body weight andmore » has a lower fat content than ovaries. Female germinal tissue can account for as much as 15% of the body weight. No major fat deposits other than those in germinal tissue were found in pike, which also had a low muscle fat content, suggesting that the importance of roe elimination in removing pollutants may be greater in pike than in salmonids. Uptake of persistent pollutants can vary greatly within a species, owing to differences in sex, age, and so forth, as well as between species, owing to differences in fat deposition strategies.« less

Dichlorodiphenyltrichloroethane (DDT), DDT Metabolites and Pregnancy Outcomes

PubMed Central

Kezios, Katrina L.; Liu, Xinhua; Cirillo, Piera M.; Cohn, Barbara A.; Kalantzi, Olga I.; Wang, Yunzhu; Petreas, Myrto X.; Park, June-Soo; Factor-Litvak, Pam

2012-01-01

Organochlorine pesticides (OCPs) are persistent endocrine disruptors. OCPs cross the placenta; this prenatal exposure has been associated with adverse pregnancy outcomes. We investigated associations between prenatal exposure to OCPs and gestational age and birth weight in 600 infants born between 1960 and 1963. The primary OCP was 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p′-DDT), its primary metabolite, 1,1′-dichloro-2,2'-bis(p-chlorophenyl)ethylene(p,p′-DDE) and the contaminant, 1,1,1-trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl)-ethane (o,p′-DDT). Regression analysis indicated that for each natural log unit increase in p,p′-DDT, birth weight increased by 274 grams (95% CI 122, 425) when controlling for p,p′-DDE and o,p′-DDT. At a given level of p,p′-DDT exposure, o,p′-DDT and p,p′-DDE were associated with decreased birth weight. p,p′-DDE was negatively associated with length of gestation, controlling for p,p′-DDT and o,p′-DDT. These findings suggest opposing associations between exposure to p,p′-DDT and p,p′-DDE and birth weight. We did not find evidence to support mediation by maternal thyroid hormone status nor that the association differed by sex. PMID:23142753

Turning crocodilian hearts into bird hearts: growth rates are similar for alligators with and without right-to-left cardiac shunt

PubMed Central

Eme, John; Gwalthney, June; Owerkowicz, Tomasz; Blank, Jason M.; Hicks, James W.

2010-01-01

The functional and possible adaptive significance of non-avian reptiles' dual aortic arch system and the ability of all non-avian reptiles to perform central vascular cardiac shunts have been of great interest to comparative physiologists. The unique cardiac anatomy of crocodilians – a four-chambered heart with the dual aortic arch system – allows for only right-to-left (R–L; pulmonary bypass) cardiac shunt and for surgical elimination of this shunt. Surgical removal of the R–L shunt, by occluding the left aorta (LAo) upstream and downstream of the foramen of Panizza, results in a crocodilian with an obligatory, avian/mammalian central circulation. In this study, R–L cardiac shunt was eliminated in age-matched, female American alligators (Alligator mississippiensis; 5–7 months of age). We tested the hypothesis that surgical elimination of R–L cardiac shunt would impair growth (a readily measured proxy for fitness) compared with sham-operated, age-matched controls, especially in animals subjected to exhaustive exercise. While regular exercise caused a decrease in size (snout-to-vent length, head length and body mass), elimination of the capacity for R–L cardiac shunt did not greatly reduce animal growth, despite a chronic ventricular enlargement in surgically altered juvenile alligators. We speculate that, despite being slightly smaller, alligators with an occluded LAo would have reached sexual maturity in the same breeding season as control alligators. This study suggests that crocodilian R–L cardiac shunt does not provide an adaptive advantage for juvenile alligator growth and supports the logic that cardiac shunts persist in crocodilians because they have not been selected against. PMID:20639429

The relationship between cavum septum pellucidum and psychopathic traits in a large forensic sample.

PubMed

Crooks, Dana; Anderson, Nathaniel E; Widdows, Matthew; Petseva, Nia; Koenigs, Michael; Pluto, Charles; Kiehl, Kent A

2018-04-01

Cavum septum pellucidum (CSP) is a neuroanatomical variant of the septum pellucidum that is considered a marker for disrupted brain development. Several small sample studies have reported CSP to be related to disruptive behavior, persistent antisocial traits, and even psychopathy. However, no large-scale samples have comprehensively examined the relationship between CSP, psychopathic traits, and antisocial behavior in forensic samples. Here we test hypotheses about the presence of CSP and its relationship to psychopathic traits in incarcerated males (N = 1432). We also examined the incidence of CSP in two non-incarcerated male control samples for comparison (N = 208 and 125). Ethnic and racial composition was varied with a mean age of 33.1, and an average IQ of 96.96. CSP was evaluated via structural magnetic resonance imaging. CSP was measured by length (number of 1.0 mm slices) in continuous analyses, and classified as absent (0) or present (1+ mm), as well as by size (absent (0), small (1-3), medium (4-5), or large (6+ mm)) for comparison with prior work. The Wechsler Adult Intelligence Scale (WAIS-III), Structured Clinical Interview (SCID-I/P), and Hare Psychopathy Checklist-Revised (PCL-R) were used to assess IQ, substance dependence, and psychopathy, respectively. CSP length was positively associated with PCL-R total, Factor 1 (interpersonal/affective) and Facets 1 (interpersonal) and 2 (affective). CSP was no more prevalent among inmates than among non-incarcerated controls, with similar distributions of size. These results support the hypotheses that abnormal septal/limbic development may contribute to dimensional affective/interpersonal traits of psychopathy, but CSP is not closely associated with antisocial behavior, per se. Published by Elsevier Ltd.

Telomere Shortening and Associated Chromosomal Instability in Peripheral Blood Lymphocytes of Patients With Hodgkin's Lymphoma Prior to Any Treatment Are Predictive of Second Cancers

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

M'kacher, Radhia; Bennaceur-Griscelli, Annelise; Girinsky, Theodore

Purpose: To investigate a potential link between telomere length, chromosomal instability, and the advent of a second cancer (SC) in patients with Hodgkin's lymphoma (HL), who are known to be at risk for SCs. This study was premised on the finding that telomere dysfunction and DNA repair pathways were related to many pathologic conditions. Methods and Materials: Three cohorts of patients with HL were studied: 73 who were prospectively followed >5 years after diagnosis (prospective HL cohort), 28 who developed a SC (SC HL cohort), and 18 long-term survivors with no evidence of disease or complication since their initial treatmentmore » (NED HL cohort). Telomere length was analyzed by a telomeric restriction fragment assay in peripheral blood lymphocytes. Thirty healthy donors and 70 patients with a newly diagnosed solid tumor were the control population. Results: Compared with controls, patients from the prospective HL cohort, before any treatment, showed age-independent shorter telomeres (mean, 8.3 vs. 11.7 kb in healthy donors; <6 kb in 18% in HL patients), increased spontaneous chromosomal abnormalities, and increased in vitro radiation sensitivity (p < 10{sup -4} each). After treatment, telomere shortening was associated with cytogenetic profiles characterized by the persistence of complex chromosomal rearrangement and clonal aberrations. Moreover, the two cases of SC in the prospective HL patients had short telomeres and CCR initially. In addition, the SC HL cohort was characterized by markedly short telomeres (6.6 vs. 9.7 kb in the NED HL cohort), the presence of complex chromosome rearrangements, and increased in vitro radiation sensitivity. Conclusions: An intimate relationship between pre-treatment telomere shortening, chromosomal instability, radiation sensitivity and occurrence of SC was found in HL patients.« less

Assessing deposition and persistence of Beauveria bassiana GHA (Ascomycota: Hypocreales) applied for control of emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae), in a commercial tree nursery

USDA-ARS?s Scientific Manuscript database

Determining the deposition and field persistence of mycoinsecticides is essential in the development of effective and economical application strategies, including specifically the timing and frequency of spray applications. In this study we used three methods to evaluate the persistence of Beauveri...

Control fast or control smart: When should invading pathogens be controlled?

PubMed

Thompson, Robin N; Gilligan, Christopher A; Cunniffe, Nik J

2018-02-01

The intuitive response to an invading pathogen is to start disease management as rapidly as possible, since this would be expected to minimise the future impacts of disease. However, since more spread data become available as an outbreak unfolds, processes underpinning pathogen transmission can almost always be characterised more precisely later in epidemics. This allows the future progression of any outbreak to be forecast more accurately, and so enables control interventions to be targeted more precisely. There is also the chance that the outbreak might die out without any intervention whatsoever, making prophylactic control unnecessary. Optimal decision-making involves continuously balancing these potential benefits of waiting against the possible costs of further spread. We introduce a generic, extensible data-driven algorithm based on parameter estimation and outbreak simulation for making decisions in real-time concerning when and how to control an invading pathogen. The Control Smart Algorithm (CSA) resolves the trade-off between the competing advantages of controlling as soon as possible and controlling later when more information has become available. We show-using a generic mathematical model representing the transmission of a pathogen of agricultural animals or plants through a population of farms or fields-how the CSA allows the timing and level of deployment of vaccination or chemical control to be optimised. In particular, the algorithm outperforms simpler strategies such as intervening when the outbreak size reaches a pre-specified threshold, or controlling when the outbreak has persisted for a threshold length of time. This remains the case even if the simpler methods are fully optimised in advance. Our work highlights the potential benefits of giving careful consideration to the question of when to start disease management during emerging outbreaks, and provides a concrete framework to allow policy-makers to make this decision.

Ablation as targeted perturbation to rewire communication network of persistent atrial fibrillation

PubMed Central

Tao, Susumu; Way, Samuel F.; Garland, Joshua; Chrispin, Jonathan; Ciuffo, Luisa A.; Balouch, Muhammad A.; Nazarian, Saman; Spragg, David D.; Marine, Joseph E.; Berger, Ronald D.; Calkins, Hugh

2017-01-01

Persistent atrial fibrillation (AF) can be viewed as disintegrated patterns of information transmission by action potential across the communication network consisting of nodes linked by functional connectivity. To test the hypothesis that ablation of persistent AF is associated with improvement in both local and global connectivity within the communication networks, we analyzed multi-electrode basket catheter electrograms of 22 consecutive patients (63.5 ± 9.7 years, 78% male) during persistent AF before and after the focal impulse and rotor modulation-guided ablation. Eight patients (36%) developed recurrence within 6 months after ablation. We defined communication networks of AF by nodes (cardiac tissue adjacent to each electrode) and edges (mutual information between pairs of nodes). To evaluate patient-specific parameters of communication, thresholds of mutual information were applied to preserve 10% to 30% of the strongest edges. There was no significant difference in network parameters between both atria at baseline. Ablation effectively rewired the communication network of persistent AF to improve the overall connectivity. In addition, successful ablation improved local connectivity by increasing the average clustering coefficient, and also improved global connectivity by decreasing the characteristic path length. As a result, successful ablation improved the efficiency and robustness of the communication network by increasing the small-world index. These changes were not observed in patients with AF recurrence. Furthermore, a significant increase in the small-world index after ablation was associated with synchronization of the rhythm by acute AF termination. In conclusion, successful ablation rewires communication networks during persistent AF, making it more robust, efficient, and easier to synchronize. Quantitative analysis of communication networks provides not only a mechanistic insight that AF may be sustained by spatially localized sources and global connectivity, but also patient-specific metrics that could serve as a valid endpoint for therapeutic interventions. PMID:28678805

Persistence of nondysplastic Barrett's esophagus identifies patients at lower risk for esophageal adenocarcinoma: results from a large multicenter cohort.

PubMed

Gaddam, Srinivas; Singh, Mandeep; Balasubramanian, Gokulakrishnan; Thota, Prashanthi; Gupta, Neil; Wani, Sachin; Higbee, April D; Mathur, Sharad C; Horwhat, John D; Rastogi, Amit; Young, Patrick E; Cash, Brooks D; Bansal, Ajay; Vargo, John J; Falk, Gary W; Lieberman, David A; Sampliner, Richard E; Sharma, Prateek

2013-09-01

Recent population-based studies have shown a low risk of esophageal adenocarcinoma (EAC) in patients with nondysplastic Barrett's esophagus (NDBE). We evaluated whether persistence of NDBE over multiple consecutive surveillance endoscopic examinations could be used in risk stratification of patients with Barrett's esophagus (BE). We performed a multicenter outcomes study of a large cohort of patients with BE. Based on the number of consecutive surveillance endoscopies showing NDBE, we identified 5 groups of patients. Patients in group 1 were found to have NDBE at their first esophagogastroduodenoscopy (EGD). Patients in group 2 were found to have NDBE on their first 2 consecutive EGDs. Similarly, patients in groups 3, 4, and 5 were found to have NDBE on 3, 4, and 5 consecutive surveillance EGDs. A logistic regression model was built to determine whether persistence of NDBE independently protected against development of cancer. Of a total of 3515 patients with BE, 1401 patients met the inclusion criteria (93.3% white; 87.5% men; median age, 60 ±17 years). The median follow-up period was 5 ± 3.9 years (7846 patient-years). The annual risk of EAC in groups 1 to 5 was 0.32%, 0.27%, 0.16%, 0.2%, and 0.11%, respectively (P for trend = .03). After adjusting for age, sex, and length of BE, persistence of NDBE, based on multiple surveillance endoscopies, was associated with a gradually lower likelihood of progression to EAC. Persistence of NDBE over several endoscopic examinations identifies patients who are at low risk for development of EAC. These findings support lengthening surveillance intervals or discontinuing surveillance of patients with persistent NDBE. Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.

Intermittent versus Persistent Wolff-Parkinson-White Syndrome in Children: Electrophysiologic Properties and Clinical Outcomes.

PubMed

Kiger, Michelle E; McCanta, Anthony C; Tong, Suhong; Schaffer, Michael; Runciman, Martin; Collins, Kathryn K

2016-01-01

Intermittent Wolff-Parkinson-White (WPW) syndrome is considered to have a lower risk of sudden death. Fewer data exist regarding electrophysiologic (EP) characteristics and the natural history of intermittent WPW in children. All patients with WPW age 1-18 years at a single institution (1996-2013) were reviewed. Patients with intermittent preexcitation were compared to those with loss of preexcitation on Holter/exercise testing and those with persistent preexcitation. High-risk accessory pathway (AP) was defined as AP effective refractory period (APERP), block cycle length, or shortest preexcited RR interval during atrial fibrillation ≤250 ms. A total of 295 patients were included: 226 (76.6%) persistent, 39 (13.2%) intermittent, and 30 (10.2%) loss of preexcitation Holter/exercise. There were no differences in symptoms between groups. Median interquartile range APERP was significantly longer in intermittent WPW (380 [320, 488] ms vs 320 [300, 350] ms persistent, 310 [290, 330] ms loss of preexcitation Holter/exercise; P = 0.0008). At baseline, there was no difference between groups in frequency of high-risk pathways. However, when isoproterenol values were included, high-risk pathways were more frequent among patients with loss of preexcitation on Holter/exercise (54% vs 16% persistent, 11% intermittent; P = 0.005). There was one death in a patient with loss of preexcitation on exercise testing, no EP study, and prior drug use. A second patient with persistent WPW and APERP 270 ms required resuscitation following a methadone overdose. Intermittent preexcitation in children does not connote a lower risk AP by EP criteria or reduced symptoms. The low number of pediatric WPW patients who develop preexcited atrial fibrillation or sudden death warrants larger studies to investigate these outcomes. ©2015 Wiley Periodicals, Inc.

Dynamic Scaling Theory of the Forced Translocation of a Semi-flexible Polymer Through a Nanopore

NASA Astrophysics Data System (ADS)

Lam, Pui-Man; Zhen, Yi

2015-10-01

We present a theoretical description of the dynamics of a semi-flexible polymer being pulled through a nanopore by an external force acting at the pore. Our theory is based on the tensile blob picture of Pincus in which the front of the tensile force propagates through the backbone of the polymer, as suggested by Sakaue and recently applied to study a completely flexible polymer with self-avoidance, by Dubbledam et al. For a semi-flexible polymer with a persistence length P, its statistics is self-avoiding for a very long chain. As the local force increases, the blob size starts to decrease. At the blob size , where a is the size of a monomer, the statistics becomes that of an ideal chain. As the blob size further decreases to below the persistence length P, the statistics is that of a rigid rod. We argue that semi-flexible polymer in translocation should include the three regions: a self-avoiding region, an ideal chain region and a rigid rod region, under uneven tension propagation, instead of a uniform scaling picture as in the case of a completely flexible polymer. In various regimes under the effect of weak, intermediate and strong driving forces we derive equations from which we can calculate the translocation time of the polymer. The translocation exponent is given by , where is an effective exponent for the end-to-end distance of the semi-flexible polymer, having a value between 1/2 and 3/5, depending on the total contour length of the polymer. Our results are of relevance for forced translocation of biological polymers such as DNA through a nanopore.

Structure of flexible and semiflexible polyelectrolyte chains in confined spaces of slit micro/nanochannels.

PubMed

Jeon, Jonggu; Chun, Myung-Suk

2007-04-21

Understanding the behavior of a polyelectrolyte in confined spaces has direct relevance in design and manipulation of microfluidic devices, as well as transport in living organisms. In this paper, a coarse-grained model of anionic semiflexible polyelectrolyte is applied, and its structure and dynamics are fully examined with Brownian dynamics (BD) simulations both in bulk solution and under confinement between two negatively charged parallel plates. The modeling is based on the nonlinear bead-spring discretization of a continuous chain with additional long-range electrostatic, Lennard-Jones, and hydrodynamic interactions between pairs of beads. The authors also consider the steric and electrostatic interactions between the bead and the confining wall. Relevant model parameters are determined from experimental rheology data on the anionic polysaccharide xanthan reported previously. For comparison, both flexible and semiflexible models are developed accompanying zero and finite intrinsic persistence lengths, respectively. The conformational changes of the polyelectrolyte chain induced by confinements and their dependence on the screening effect of the electrolyte solution are faithfully characterized with BD simulations. Depending on the intrinsic rigidity and the medium ionic strength, the polyelectrolyte can be classified as flexible, semiflexible, or rigid. Confined flexible and semiflexible chains exhibit a nonmonotonic variation in size, as measured by the radius of gyration and end-to-end distance, with changing slit width. For the semiflexible chain, this is coupled to the variations in long-range bond vector correlation. The rigid chain, realized at low ionic strength, does not have minima in size but exhibits a sigmoidal transition. The size of confined semiflexible and rigid polyelectrolytes can be well described by the wormlike chain model once the electrostatic effects are taken into account by the persistence length measured at long length scale.

Influence of patient training on persistence, compliance, and tolerability of different dosing frequency regimens of bisphosphonate therapy: An observational study in Turkish patients with postmenopausal osteoporosis.

PubMed

Akarırmak, Ülkü; Koçyiğit, Hikmet; Eskiyurt, Nurten; Esmaeilzadeh, Sina; Kuru, Ömer; Yalçinkaya, Ebru Yılmaz; Peker, Özlen; Ekim, Ayşe Aydemir; Özgirgin, Neşe; Çalış, Mustafa; Rezvani, Aylin; Çevikol, Alev; Eyigör, Sibel; Şendur, Ömer Faruk; İrdesel, Jale

2016-08-01

In our study, we aimed to evaluate the influence of training on compliance and persistence with bisphosphonate treatment given on a weekly vs. monthly basis in postmenopausal osteoporosis patients. A total of 979 patients with postmenopausal osteoporosis (mean age: 63.2 ± 7.2 years) were included in this national, multicenter, prospective non-interventional observational cohort registry study. Patients were randomized into training (n = 492, 50.3%, mean age: 63.4 ± 7.2 years) and control (n = 487, 49.7%, mean age: 63.0 ± 7.1 years) groups. Patients in each intervention group were given weekly (44.9% and 44.6% for training and control subjects, respectively) or monthly (55.1% and 55.4%, respectively) bisphosphonate regimens. After the initial visit, patients were followed up at three-month intervals throughout 12 months of treatment for evaluation of persistence, compliance and adverse events. On average, 79.4% of the patients were persistent with the treatment with a mean of 350.4 days of duration during the 12-month follow-up period. The mean compliance in the compliant and fully compliant group remained at an average of 86.6%. No significant difference was detected between the training and control groups in terms of compliance and persistence. Significantly longer persistence (360.0 ± 89.0 vs. 345.0 ± 108.0 days; p = 0.035), higher percentage of persistent patients (83.4% vs. 74.2%; p = 0.012) and higher compliance rates (88.8% vs. 83.3%; p = 0.002) were noted in monthly regimen patients in comparison to those given weekly regimen. Our findings revealed remarkably high rates for persistence and compliance with bisphosphonate treatment in postmenopausal osteoporosis, with no impact of training on compliance and persistence rates. Longer persistence and better compliance rates were achieved with the monthly bisphosphonate regimen when compared to the weekly regimen. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Solution-Phase Conformation and Dynamics of Conjugated Isoindigo-Based Donor–Acceptor Polymer Single Chains

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

Lee, Franklin L.; Farimani, Amir Barati; Gu, Kevin L.

Conjugated polymers are the key material in thin-film organic optoelectronic devices due to the versatility of these molecules combined with their semiconducting properties. A molecular-scale understanding of conjugated polymers is important to the optimization of the thin-film morphology. We examine the solution-phase behavior of conjugated isoindigo-based donor–acceptor polymer single chains of various chain lengths using atomistic molecular dynamics simulations. Our simulations elucidate the transition from a rod-like to a coil-like conformation from an analysis of normal modes and persistence length. In addition, we find another transition based on the solvent environment, contrasting the coil-like conformation in a good solvent withmore » a globule-like conformation in a poor solvent. Altogether, our results provide valuable insights into the transition between conformational regimes for conjugated polymers as a function of both the chain length and the solvent environment, which will help to accurately parametrize higher level models.« less

Solution-Phase Conformation and Dynamics of Conjugated Isoindigo-Based Donor–Acceptor Polymer Single Chains

DOE PAGES

Lee, Franklin L.; Farimani, Amir Barati; Gu, Kevin L.; ...

2017-10-25

Conjugated polymers are the key material in thin-film organic optoelectronic devices due to the versatility of these molecules combined with their semiconducting properties. A molecular-scale understanding of conjugated polymers is important to the optimization of the thin-film morphology. We examine the solution-phase behavior of conjugated isoindigo-based donor–acceptor polymer single chains of various chain lengths using atomistic molecular dynamics simulations. Our simulations elucidate the transition from a rod-like to a coil-like conformation from an analysis of normal modes and persistence length. In addition, we find another transition based on the solvent environment, contrasting the coil-like conformation in a good solvent withmore » a globule-like conformation in a poor solvent. Altogether, our results provide valuable insights into the transition between conformational regimes for conjugated polymers as a function of both the chain length and the solvent environment, which will help to accurately parametrize higher level models.« less

Telomere Length Determines TERRA and R-Loop Regulation through the Cell Cycle.

PubMed

Graf, Marco; Bonetti, Diego; Lockhart, Arianna; Serhal, Kamar; Kellner, Vanessa; Maicher, André; Jolivet, Pascale; Teixeira, Maria Teresa; Luke, Brian

2017-06-29

Maintenance of a minimal telomere length is essential to prevent cellular senescence. When critically short telomeres arise in the absence of telomerase, they can be repaired by homology-directed repair (HDR) to prevent premature senescence onset. It is unclear why specifically the shortest telomeres are targeted for HDR. We demonstrate that the non-coding RNA TERRA accumulates as HDR-promoting RNA-DNA hybrids (R-loops) preferentially at very short telomeres. The increased level of TERRA and R-loops, exclusively at short telomeres, is due to a local defect in RNA degradation by the Rat1 and RNase H2 nucleases, respectively. Consequently, the coordination of TERRA degradation with telomere replication is altered at shortened telomeres. R-loop persistence at short telomeres contributes to activation of the DNA damage response (DDR) and promotes recruitment of the Rad51 recombinase. Thus, the telomere length-dependent regulation of TERRA and TERRA R-loops is a critical determinant of the rate of replicative senescence. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of spectacle treatment in patients with mild traumatic brain injury: a pilot study.

PubMed

Johansson, Jan; Nygren de Boussard, Catharina; Öqvist Seimyr, Gustaf; Pansell, Tony

2017-05-01

Visual symptoms and dysfunctions may be a part of the long-term issues following mild traumatic brain injury. These issues may have an impact on near work and reading, and thus affect activities of daily life and the ability to return to work. The purpose of the study was to assess the effect of spectacle treatment on near work-related visual symptoms, visual function and reading performance in patients with persisting symptoms after mild traumatic brain injury. Eight patients with persisting symptoms after mild traumatic brain injury and anomalies of binocular function were included. Binocular function, visual symptoms and reading performance were assessed before and after spectacle treatment. Reading eye movements were recorded with eye tracking. Four patients showed a considerable symptom reduction along with minor improvement in clinical visual measures. Reading performance improved in four patients; however, the relationship to symptom reduction was inconsistent. The improvement was correlated to reduced average number of fixations per word (r = -0.89, p = 0.02), reduced proportion of regressive saccades (r = -0.93, p = 0.01) and a significant increase of mean progressive saccade length (p = 0.03). This pilot study found that spectacle treatment, specifically directed at optimising near task visual function, significantly reduced symptoms in 50 per cent of patients and improved reading performance in 50 per cent. While promising, lack of placebo control and lack of correlation between reading performance and symptom improvements means we cannot decipher mechanisms without further study. © 2016 Optometry Australia.

Mechanical transduction via a single soft polymer

NASA Astrophysics Data System (ADS)

Hou, Ruizheng; Wang, Nan; Bao, Weizhu; Wang, Zhisong

2018-04-01

Molecular machines from biology and nanotechnology often depend on soft structures to perform mechanical functions, but the underlying mechanisms and advantages or disadvantages over rigid structures are not fully understood. We report here a rigorous study of mechanical transduction along a single soft polymer based on exact solutions to the realistic three-dimensional wormlike-chain model and augmented with analytical relations derived from simpler polymer models. The results reveal surprisingly that a soft polymer with vanishingly small persistence length below a single chemical bond still transduces biased displacement and mechanical work up to practically significant amounts. This "soft" approach possesses unique advantages over the conventional wisdom of rigidity-based transduction, and potentially leads to a unified mechanism for effective allosterylike transduction and relay of mechanical actions, information, control, and molecules from one position to another in molecular devices and motors. This study also identifies an entropy limit unique to the soft transduction, and thereby suggests a possibility of detecting higher efficiency for kinesin motor and mutants in future experiments.

Management of chlorine gas-related injuries from the Graniteville, South Carolina, train derailment.

PubMed

Mackie, Emily; Svendsen, Erik; Grant, Stephen; Michels, Jill E; Richardson, William H

2014-10-01

A widely produced chemical, chlorine is used in various industries including automotive, electronics, disinfectants, metal production, and many others. Chlorine is usually produced and transported as a pressurized liquid; however, as a gas it is a significant pulmonary irritant. Thousands of people are exposed to chlorine gas every year, and while large-scale exposures are uncommon, they are not rare. Symptoms are usually related to the concentration and length of exposure, and although treatment is largely supportive, certain specific therapies have yet to be validated with randomized controlled trials. The majority of those exposed completely recover with supportive care; however, studies have shown the potential for persistent inflammation and chronic hyperreactivity. This case report describes an incident that occurred in Graniteville, South Carolina, when a train derailment exposed hundreds of people to chlorine gas. This report reviews the events of January 6, 2005, and the current treatment options for chlorine gas exposure.(Disaster Med Public Health Preparedness. 2014;0:1-6).

Hot particles attract in a cold bath

NASA Astrophysics Data System (ADS)

Tanaka, Hidenori; Lee, Alpha A.; Brenner, Michael P.

2017-04-01

Controlling interactions out of thermodynamic equilibrium is crucial for designing addressable and functional self-organizing structures. These active interactions also underpin collective behavior in biological systems. Here we study a general setting of active particles in a bath of passive particles and demonstrate a mechanism for long-range attraction between active particles. The mechanism operates when the translational persistence length of the active particle motion is smaller than the particle diameter. In this limit, the system reduces to particles of higher diffusivity ("hot" particles) in a bath of particles with lower diffusivity ("cold" particles). This attractive interaction arises as a hot particle pushes cold particles away to create a large hole around itself, and the holes interact via a depletion-like attraction. Strikingly, the interaction range is more than an order of magnitude larger than the particle radius, well beyond the range of the conventional depletion force. Although the mechanism occurs outside the parameter regime of typical biological swimmers, the mechanism could be realized in the laboratory.

Visualizing Coolant Flow in Sodium Reactor Subassemblies

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

None

2010-01-01

Uniformity of temperature controls peak power output. Interchannel cross-flow is the principal cross-assembly energy transport mechanism. The areas of fastest flow all occur at the exterior of the assembly. Further, the fast moving region winds around the assembly in a continuous swath. This Nek5000 simulation uses an unstructured mesh with over one billion grid points, resulting in five billion degrees of freedom per time slice. High speed patches of turbulence due to vertex shedding downstream of the wires persist for about a quarter of the wire-wrap periodic length. Credits: Science: Paul Fisher and Aleks Obabko, Argonne National Laboratory. Visualization: Hankmore » Childs and Janet Jacobsen, Lawrence Berkeley National Laboratory. This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Dept. of Energy under contract DE-AC02-06CH11357. This research was sponsored by the Department of Energy's Office of Nuclear Energy's NEAMS program.« less

Pulmonary cellular effects in rats following aerosol exposures to ultrafine Kevlar aramid fibrils: evidence for biodegradability of inhaled fibrils.

PubMed

Warheit, D B; Kellar, K A; Hartsky, M A

1992-10-01

Previous chronic inhalation studies have shown that high concentrations of Kevlar fibrils produced fibrosis and cystic keratinizing tumors in rats following 2-year inhalation exposures. The current studies were undertaken to evaluate mechanisms and to assess the toxicity of inhaled Kevlar fibrils relative to other reference materials. Rats were exposed to ultrafine Kevlar fibers (fibrils) for 3 or 5 days at concentrations ranging from 600-1300 fibers/cc (gravimetric concentrations ranging from 2-13 mg/m3). A complete characterization of the fiber aerosol and dose was carried out. These measurements included gravimetric concentrations, mass median aerodynamic diameter, fiber number, and count median lengths and diameters of the aerosol. Following exposures, cells and fluids from groups of sham- and fiber-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, lactate dehydrogenase (LDH), protein, and N-acetyl glucosaminidase (NAG) values were measured in BAL fluids at several time points postexposure. Alveolar macrophages were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy. The lungs of additional exposed animals were processed for deposition, cell labeling, retained dose, and lung clearance studies, as well as fiber dimensions (from digested lung tissue), histopathology, and transmission electron microscopy. Five-day exposures to Kevlar fibrils elicited a transient granulocytic inflammatory response with concomitant increases in BAL fluid levels of alkaline phosphatase, NAG, LDH, and protein. Unlike the data from silica and asbestos exposures where inflammation persisted, biochemical parameters returned to control levels at time intervals between 1 week and 1 month postexposure. Macrophage function in Kevlar-exposed alveolar macrophages was not significantly different from sham controls at any time period. Cell labeling studies were carried out immediately after exposure, as well as 1 week and 1 month postexposure. Increased pulmonary cell labeling was measured in terminal bronchiolar cells immediately after exposure but returned to control values 1 week later. Fiber clearance studies demonstrated a transient increase in the numbers of retained fibers at 1 week postexposure, with rapid clearance of fibers thereafter. The transient increase in the number of fibers could be due to transverse cleaving of the fibers, since the average lengths of retained fibers continued to decrease over time. In this regard, a progressive decrease in the mean lengths and diameters of inhaled fibers was measured over a 6-month postexposure period.(ABSTRACT TRUNCATED AT 400 WORDS)

Electrophysiology and structural interventions in adults with congenital heart disease: Comparison of combined versus separate procedures.

PubMed

Lindsay, Ian; Nik-Ahd, Farnoosh; Aboulhosn, Jamil A; Moore, Jeremy P

2018-05-18

Electrophysiologic (EP) and structural interventions in adult congenital heart disease (ACHD) are typically completed during separate hospital encounters. With planning/coordination, these cases can be combined. We hypothesized that this integrated approach would yield patient and health system benefits. Consecutive ACHD patients undergoing combined interventions were matched to controls with identical but separate procedures. Primary endpoints of total hospital length of stay and cost were compared. Sixty-six combined cases and 120 controls were identified (45% male, mean age 36.2 ± 14.2 years). The most common diagnoses were Fontan (27%), tetralogy of Fallot (23%), and transposition complexes (20%). The most common EP procedure was catheter ablation (n = 30) followed by electrophysiologic study (n = 13); the most common structural intervention was transcatheter valve replacement (n = 16) followed by angioplasty/stenting (n = 14). Compared to controls, cases showed shorter anesthesia duration (323 [IQR 238-405] vs. 355 minutes [270-498], P = 0.06), smaller contrast dose (130 [50-189] vs. 177 mL [94-228], P = 0.045), fewer venipunctures (4 [3-4] vs. 6 [5-7], P < 0.001), and fewer work days missed (2 [2-5] vs. 4 [4-6], P < 0.001). There was shorter hospital stay (30 [19-35] vs. 38 hours [26-50], P = 0.023) and a 37% reduction in hospital charges ($117,894 vs. $187,648; P = 0.039) and 27% reduction in payments ($65,757 vs. $88,859; P = 0.016), persisting after adjustment for group differences. There were no significant differences in number of complications or efficacy. There appear to be advantages to combining ACHD interventional procedures that include reductions in hospital length of stay and cost, without detectable difference in procedural outcome. Published 2018. This article is a U.S. Government work and is in the public domain in the U.S.A.

Trauma systems and the costs of trauma care.

PubMed Central

Goldfarb, M G; Bazzoli, G J; Coffey, R M

1996-01-01

OBJECTIVE. This study examines the cost of providing trauma services in trauma centers organized by publicly administered trauma systems, compared to hospitals not part of a formal trauma system. DATA SOURCES AND STUDY SETTING. Secondary administrative discharge abstracts for a national sample of severely injured trauma patients in 44 trauma centers and 60 matched control hospitals for the year 1987 were used. STUDY DESIGN. Retrospective univariate and multivariate analyses were conducted to examine the impact of formal trauma systems and trauma center designation on the costs of treating trauma patients. Key dependent variables included length of stay, charge per day per patient, and charge per hospital stay. Key impact variables were type of trauma system and level of trauma designation. Control variables included patient, hospital, and community characteristics. DATA COLLECTION/EXTRACTION METHODS. Data were selected for hospitals based on (1) a large national hospital discharge database, the Hospital Cost and Utilization Project, 1980-1987 (HCUP-2) and (2) a special survey of trauma systems and trauma designation undertaken by the Hospital Research and Educational Trust of the American Hospital Association. PRINCIPAL FINDINGS. The results show that publicly designated Level I trauma centers, which are the focal point of most trauma systems, have the highest charge per case, the highest average charge per day, and similar or longer average lengths of stay than other hospitals. These findings persist after controlling for patient injury and health status, and for demographic characteristics and hospital and community characteristics. CONCLUSIONS. Prior research shows that severely injured trauma patients have greater chances of survival when treated in specialized trauma centers. However, findings here should be of concern to the many states developing trauma systems since the high costs of Level I centers support limiting the number of centers designated at this level and/or reconsidering the requirements placed on these centers. PMID:8617611

Degradation of the Herbicide (2,4-Dichlorophenoxyacetic Acid) Using a Photoreactor with Exciplex Lamps

NASA Astrophysics Data System (ADS)

Vershinin, N. O.; Sokolova, I. V.; Tchaikovskaya, O. N.

2013-09-01

We present the results of tests of a compact flow-through reactor for neutralization of a broad class of persistent toxic compounds. As the toxicant we used the herbicide 2,4-dichlorophenoxyacetic acid, and we used exciplex lamps with different emission wave lengths (λ ~ 222 nm and 172 nm). We show the experimental decrease in the amount of organic compounds vs. irradiation time as obtained from the absorption spectra.

Application of the Augmented Operator Function Model for Developing Cognitive Metrics in Persistent Surveillance

DTIC Science & Technology

2013-09-26

vehicle-lengths between frames. The low specificity of object detectors in WAMI means all vehicle detections are treated equally. Motion clutter...timing of the anomaly . If an anomaly was detected , recent activity would have a priority over older activity. This is due to the reasoning that if the...this could be a potential anomaly detected . Other baseline activities include normal work hours, religious observance times and interactions between

Light scattering measurement of sodium polyacrylate products

NASA Astrophysics Data System (ADS)

Lama, Nisha; Norwood, David; Boone, Steven; Massie-Boyer, Valerie

2015-03-01

In the presentation, we will describe the use of a multi-detector HPLC incorporating the DAWN EOS multi-angle laser light scattering (MALLS) detector to measure the properties such as molecular weight, RMS radius, contour and persistence length and polydispersity of sodium polyacrylate products. The samples of sodium polyacrylate are used in various industries as thickening agents, coating dispersants, artificial snow, laundry detergent and disposable diapers. Data and results obtained from the experiment will be presented.

Fragment Capture Simulation for MANPADS Test Arena Optimization

DTIC Science & Technology

2014-03-27

length and weighing 13 to 25 kilograms (Bureau of Political- Military Affairs, 2011). Examples of MANPADS include the SA-7b and the SA-14. A MANPADS...terrorist activities. An estimated 500,000-750,000 MANPADS remain stockpiled worldwide, making them a persistent threat to both military and civilian...aircraft (Schroeder, 2007). According to the U.S. State Department’s Bureau of Political- Military Affairs, curbing the spread of MANPADS is a top priority

Chronic symptoms are common in patients with neuroborreliosis -- a questionnaire follow-up study.

PubMed

Vrethem, M; Hellblom, L; Widlund, M; Ahl, M; Danielsson, O; Ernerudh, J; Forsberg, P

2002-10-01

The existence of chronic neuroborreliosis is controversial. The aim of our study was to investigate the existence and kind of persistent symptoms in patients previously treated because of neurological symptoms as a result of neuroborreliosis. A total of 106 patients with neuroborreliosis, according to established criteria, and a control group of 123 patients with Borrelia induced erythema migrans diagnosed in a general practitioner office were studied. A questionnaire was sent to patients and controls concerning their health situation. Time from onset of neurological symptoms to the questionnaire send out was 32 months (mean) for the patients with neuroborreliosis and 33 months (mean) for the controls. Fifty per cent of the individuals in the patient group compared with 16% of the individuals in the control group showed persistent complaints after their Borrelia infection (P < 0.0001). The most significant differences between the groups were the presence of neuropsychiatric symptoms such as headache, attention problems, memory difficulties and depression. Paresthesia, pain and persistent facial palsy was also significantly more common in patients treated because of neuroborreliosis. Our study shows that persisting neurological symptoms are common after a neuroborreliosis infection. The pathological mechanisms that lay behind the development of chronic symptoms, however, are still uncertain.

Cortical dynamics of feature binding and reset: control of visual persistence.

PubMed

Francis, G; Grossberg, S; Mingolla, E

1994-04-01

An analysis of the reset of visual cortical circuits responsible for the binding or segmentation of visual features into coherent visual forms yields a model that explains properties of visual persistence. The reset mechanisms prevent massive smearing of visual percepts in response to rapidly moving images. The model simulates relationships among psychophysical data showing inverse relations of persistence to flash luminance and duration, greater persistence of illusory contours than real contours, a U-shaped temporal function for persistence of illusory contours, a reduction of persistence due to adaptation with a stimulus of like orientation, an increase of persistence with spatial separation of a masking stimulus. The model suggests that a combination of habituative, opponent, and endstopping mechanisms prevent smearing and limit persistence. Earlier work with the model has analyzed data about boundary formation, texture segregation, shape-from-shading, and figure-ground separation. Thus, several types of data support each model mechanism and new predictions are made.

Characterizing the human postural control system using detrended fluctuation analysis

NASA Astrophysics Data System (ADS)

Teresa Blázquez, M.; Anguiano, Marta; de Saavedra, Fernando Arias; Lallena, Antonio M.; Carpena, Pedro

2010-01-01

Detrended fluctuation analysis is used to study the behaviour of the time series of the position of the center of pressure, output from the activity of a human postural control system. The results suggest that these trajectories present a crossover in their scaling properties from persistent (for high frequencies, short-range time scale) to anti-persistent (for low frequencies, long-range time scale) behaviours. The values of the scaling exponent found for the persistent parts of the trajectories are very similar for all the cases analysed. The similarity of the results obtained for the measurements done with both eyes open and both eyes closed indicate either that the visual system may be disregarded by the postural control system, while maintaining quiet standing, or that the control mechanisms associated with each type of information (visual, vestibular and somatosensory) cannot be disentangled with this technique.

Long term persistence of anti-HBs protective levels in young patients with type 1 diabetes after recombinant hepatitis B vaccine.

PubMed

Marseglia, G; Alibrandi, A; d'Annunzio, G; Gulminetti, R; Avanzini, M A; Marconi, M; Tinelli, C; Lorini, R

2000-11-22

The aim of the present study was to evaluate the persistence of anti-hepatitis B protective levels in young patients with type 1 diabetes, successfully immunised with a recombinant hepatitis B vaccine. We re-evaluated, after a 4 year follow-up, 54 patients and 70 age and sex-matched healthy subjects. Protective antibodies levels were found in 50/54 (92%) patients and in 67/70 (96%) controls. Moreover, anti-HBs levels were similar in diabetic patients and controls (means of log-titre and (sd); 1.95 (0.88) and 2.18 (0.64) patients and controls, respectively; P=0.11). No cases of clinical hepatitis were reported and all patients and controls remained HBc negative. These data demonstrate the persistence of anti-HBs levels in children, adolescents and young patients with type 1 diabetes after recombinant hepatitis B vaccine showing evidence of longterm immunogenity and protective effect.

Evolving strategies for the treatment of aortoenteric fistulas.

PubMed

Baril, Donald T; Carroccio, Alfio; Ellozy, Sharif H; Palchik, Eugene; Sachdev, Ulka; Jacobs, Tikva S; Marin, Michael L

2006-08-01

Aortoenteric fistulas (AEFs) are a rare but often fatal cause of gastrointestinal bleeding. Operative repair of AEF has been historically associated with extremely high morbidity and mortality. We reviewed our experience of open surgical and endovascular treatment of AEF to compare outcomes over a contemporaneous time period. Over a 9-year period between January 1997 and January 2006, 16 patients (11 men and 5 women) were diagnosed with and treated for AEFs. Seven patients underwent open surgical repair, and nine, with anatomically suitable lesions, underwent endovascular repair. The outcome after treatment of these patients was investigated for survival, perioperative complications, length of hospital stay, and long-term disposition. Three primary and 13 secondary AEFs were treated. The mean time from the initial aortic operation until AEF diagnosis was 5.9 years (range, 0.7-12.2 years) for patients with secondary AEFs. The overall 30-day mortality rate was 18.8%. One intraoperative death and one in-hospital death secondary to multisystem organ failure occurred in patients undergoing open repair. One in-hospital death related to persistent sepsis occurred in the endovascular group. The overall perioperative complication rate was 50.0%. Complications in the open group included sepsis, renal failure, bowel obstruction, and pancreatitis. Complications in the endovascular group were related to persistent sepsis. The mean in-hospital length of stay was significantly longer for patients undergoing open repair compared with endovascular repair (44.0 vs 19.4 days; P = .04). Four (80%) of five patients who were discharged from the hospital in the open group were placed in skilled nursing facilities, and seven (87.5%) of eight patients discharged in the endovascular group returned home. The median overall survival after hospital discharge was 23.1 months. There were no late aneurysm-related deaths or late deaths related to septic complications. Patients with AEFs have limited overall survival. Endovascular therapy offers an alternative to open surgical repair, seems to be associated with decreased perioperative morbidity and mortality and a shorter in-hospital stay, and allows for acceptable survival given the presence of coexisting medical comorbidities. Furthermore, endovascular repair provides a therapeutic option to control bleeding and allow for continued intervention in a stabilized setting.

Log Distribution, Persistence, and Geomorphic Function in Streams and Rivers, in the Northeastern U.S.

NASA Astrophysics Data System (ADS)

St Pierre, L.; Burchsted, D.; Warren, D.

2015-12-01

Large wood provides critical ecosystem services such as fish habitat, temperature regulation and bank stabilization. In the northeastern U.S., the distribution of large wood is documented; however, there is little understanding of the movement, longevity and geomorphic function. This research examines the hypothesis that tree species control the persistence and geomorphic function of instream wood in the Appalachian region of the northeastern U.S. To do this, we assessed size, location, and species of logs in New Hampshire rivers, including locations in the White Mountain National Forest (WMNF) where these data were collected ten years ago. We expanded the previous dataset to include assessment of geomorphic function, including creation of diversion channels, pool formation, and sediment storage, among others. We also added new sites in the WMNF and sites on a large rural river in southwestern NH to increase the range of geomorphic variables to now include: confined and unconfined channels; 1st to 4th order streams; low to high gradient; meandering, multithreaded, and straight channels; and land use such as historic logging, modern agriculture, and post-agricultural abandonment. At each study site, we located all large logs (>10cm diameter, > 1m length) and log jams (>3 accumulated logs that provide a geomorphic function) along 100m-700m reaches. We marked each identified log with a numbered tag and recorded species, diameter, length, orientation, GPS location, tag number, and photographs. We assessed function and accumulation, decay, stability, and source classes for each log. Along each reach we measured riparian forest composition and structure and channel width. Preliminary analysis suggests that tree species significantly affects the function of logs: yellow birch and American sycamore are highly represented. Additionally, geomorphic setting also plays a primary role, where unconfined reaches have large logs that provide important functions; those functions are rarely contributed by logs in confined channels. Land use limit the ability of logs to provide habitat for vegetation recruitment, notable in rivers adjacent to agricultural areas that maintain a straight channel; invasive vegetation dominate the banks and there is little to no recruitment of native vegetation.

Diagnosis of neglected tropical diseases among patients with persistent digestive disorders (diarrhoea and/or abdominal pain ≥14 days): Pierrea multi-country, prospective, non-experimental case-control study.

PubMed

Polman, Katja; Becker, Sören L; Alirol, Emilie; Bhatta, Nisha K; Bhattarai, Narayan R; Bottieau, Emmanuel; Bratschi, Martin W; Burza, Sakib; Coulibaly, Jean T; Doumbia, Mama N; Horié, Ninon S; Jacobs, Jan; Khanal, Basudha; Landouré, Aly; Mahendradhata, Yodi; Meheus, Filip; Mertens, Pascal; Meyanti, Fransiska; Murhandarwati, Elsa H; N'Goran, Eliézer K; Peeling, Rosanna W; Ravinetto, Raffaella; Rijal, Suman; Sacko, Moussa; Saye, Rénion; Schneeberger, Pierre H H; Schurmans, Céline; Silué, Kigbafori D; Thobari, Jarir A; Traoré, Mamadou S; van Lieshout, Lisette; van Loen, Harry; Verdonck, Kristien; von Müller, Lutz; Yansouni, Cédric P; Yao, Joel A; Yao, Patrick K; Yap, Peiling; Boelaert, Marleen; Chappuis, François; Utzinger, Jürg

2015-08-18

Diarrhoea still accounts for considerable mortality and morbidity worldwide. The highest burden is concentrated in tropical areas where populations lack access to clean water, adequate sanitation and hygiene. In contrast to acute diarrhoea (<14 days), the spectrum of pathogens that may give rise to persistent diarrhoea (≥14 days) and persistent abdominal pain is poorly understood. It is conceivable that pathogens causing neglected tropical diseases play a major role, but few studies investigated this issue. Clinical management and diagnostic work-up of persistent digestive disorders in the tropics therefore remain inadequate. Hence, important aspects regarding the pathogenesis, epidemiology, clinical symptomatology and treatment options for patients presenting with persistent diarrhoea and persistent abdominal pain should be investigated in multi-centric clinical studies. This multi-country, prospective, non-experimental case-control study will assess persistent diarrhoea (≥14 days; in individuals aged ≥1 year) and persistent abdominal pain (≥14 days; in children/adolescents aged 1-18 years) in up to 2000 symptomatic patients and 2000 matched controls. Subjects from Côte d'Ivoire, Indonesia, Mali and Nepal will be clinically examined and interviewed using a detailed case report form. Additionally, each participant will provide a stool sample that will be examined using a suite of diagnostic methods (i.e., microscopic techniques, rapid diagnostic tests, stool culture and polymerase chain reaction) for the presence of bacterial and parasitic pathogens. Treatment will be offered to all infected participants and the clinical treatment response will be recorded. Data obtained will be utilised to develop patient-centred clinical algorithms that will be validated in primary health care centres in the four study countries in subsequent studies. Our research will deepen the understanding of the importance of persistent diarrhoea and related digestive disorders in the tropics. A diversity of intestinal pathogens will be assessed for potential associations with persistent diarrhoea and persistent abdominal pain. Different diagnostic methods will be compared, clinical symptoms investigated and diagnosis-treatment algorithms developed for validation in selected primary health care centres. The findings from this study will improve differential diagnosis and evidence-based clinical management of digestive syndromes in the tropics. ClinicalTrials.gov; identifier: NCT02105714 .

Transpalatal insertion of radioactive gold grain for the treatment of persistent and recurrent nasopharyngeal carcinoma.

PubMed

Choy, D; Sham, J S; Wei, W I; Ho, C M; Wu, P M

1993-02-15

To evaluate the efficacy of radioactive gold grain implant via the split palate approach in the control of locally recurrent or persistent nasopharyngeal carcinoma. Forty-three patients, 10 for persistent NPC, 28 for first relapse in the nasopharynx, and five for second relapse in the nasopharynx, were treated. The diameter of the tumors at the time of gold grain implant ranged from 0.5 to 5 cm, the number of gold grains inserted varied from 4 to 14, the median number was seven. There was no significant difference in the control of the primary tumor for persistent disease (80% at 5 years), first relapse (61% at 5 years) and second relapse (80% at 3 years), p = 0.8845. The difference in survival between the three subgroups of patients, however, was highly significant (p = 0.0040). Thirty patients had CT evaluation before gold grain implant and the tumor was found confined to the nasopharynx in 21, in the remaining nine patients erosion of the sphenoid sinus or other parts of the base of skull was noted. The difference in the control between those patients with tumors confined to the nasopharynx and those patients with extranasopharyngeal extension of tumor almost reached statistical significance (81% and 44% respectively at 5 years, p = 0.0554). For the six patients who developed local recurrence after gold grain implant and were evaluable for the pattern of failure, the recurrent tumors were considered originating from another region of the nasopharynx in four, and in-field failure in the other two cases. Radioactive gold grain implant as salvage treatment provides satisfactory control of persistent and recurrent nasopharyngeal carcinoma. The local control was better when the tumor was localized to the nasopharynx, thus underlines the importance of close follow-up for early recognition of relapse and persistent tumor. However, such patients still suffered from high incidence of regional and distant failure, the pathophysiology and management of which require further investigation.

Path planning for persistent surveillance applications using fixed-wing unmanned aerial vehicles

NASA Astrophysics Data System (ADS)

Keller, James F.

This thesis addresses coordinated path planning for fixed-wing Unmanned Aerial Vehicles (UAVs) engaged in persistent surveillance missions. While uniquely suited to this mission, fixed wing vehicles have maneuver constraints that can limit their performance in this role. Current technology vehicles are capable of long duration flight with a minimal acoustic footprint while carrying an array of cameras and sensors. Both military tactical and civilian safety applications can benefit from this technology. We make three main contributions: C1 A sequential path planner that generates a C 2 flight plan to persistently acquire a covering set of data over a user designated area of interest. The planner features the following innovations: • A path length abstraction that embeds kino-dynamic motion constraints to estimate feasible path length. • A Traveling Salesman-type planner to generate a covering set route based on the path length abstraction. • A smooth path generator that provides C 2 routes that satisfy user specified curvature constraints. C2 A set of algorithms to coordinate multiple UAVs, including mission commencement from arbitrary locations to the start of a coordinated mission and de-confliction of paths to avoid collisions with other vehicles and fixed obstacles. C3 A numerically robust toolbox of spline-based algorithms tailored for vehicle routing validated through flight test experiments on multiple platforms. A variety of tests and platforms are discussed. The algorithms presented are based on a technical approach with approximately equal emphasis on analysis, computation, dynamic simulation, and flight test experimentation. Our planner (C1) directly takes into account vehicle maneuverability and agility constraints that could otherwise render simple solutions infeasible. This is especially important when surveillance objectives elevate the importance of optimized paths. Researchers have developed a diverse range of solutions for persistent surveillance applications but few directly address dynamic maneuver constraints. The key feature of C1 is a two stage sequential solution that discretizes the problem so that graph search techniques can be combined with parametric polynomial curve generation. A method to abstract the kino-dynamics of the aerial platforms is then presented so that a graph search solution can be adapted for this application. An A* Traveling Salesman Problem (TSP) algorithm is developed to search the discretized space using the abstract distance metric to acquire more data or avoid obstacles. Results of the graph search are then transcribed into smooth paths based on vehicle maneuver constraints. A complete solution for a single vehicle periodic tour of the area is developed using the results of the graph search algorithm. To execute the mission, we present a simultaneous arrival algorithm (C2) to coordinate execution by multiple vehicles to satisfy data refresh requirements and to ensure there are no collisions at any of the path intersections. We present a toolbox of spline-based algorithms (C3) to streamline the development of C2 continuous paths with numerical stability. These tools are applied to an aerial persistent surveillance application to illustrate their utility. Comparisons with other parametric polynomial approaches are highlighted to underscore the benefits of the B-spline framework. Performance limits with respect to feasibility constraints are documented.

Twist-writhe partitioning in a coarse-grained DNA minicircle model

NASA Astrophysics Data System (ADS)

Sayar, Mehmet; Avşaroǧlu, Barış; Kabakçıoǧlu, Alkan

2010-04-01

Here we present a systematic study of supercoil formation in DNA minicircles under varying linking number by using molecular-dynamics simulations of a two-bead coarse-grained model. Our model is designed with the purpose of simulating long chains without sacrificing the characteristic structural properties of the DNA molecule, such as its helicity, backbone directionality, and the presence of major and minor grooves. The model parameters are extracted directly from full-atomistic simulations of DNA oligomers via Boltzmann inversion; therefore, our results can be interpreted as an extrapolation of those simulations to presently inaccessible chain lengths and simulation times. Using this model, we measure the twist/writhe partitioning in DNA minicircles, in particular its dependence on the chain length and excess linking number. We observe an asymmetric supercoiling transition consistent with experiments. Our results suggest that the fraction of the linking number absorbed as twist and writhe is nontrivially dependent on chain length and excess linking number. Beyond the supercoiling transition, chains of the order of one persistence length carry equal amounts of twist and writhe. For longer chains, an increasing fraction of the linking number is absorbed by the writhe.

Lag-length effect on repetition priming of famous and unfamiliar faces: evidence from N250r and N400.

PubMed

Nie, Aiqing; Li, Minye; Ye, Jingheng

2016-07-06

Previous event-related potentials research has reliably identified two repetition priming components in faces, the N250r and the N400, which are believed to reflect, respectively, the accessing to the stored structural representations and the semantic retrieval. However, the effect of lags longer than immediate repetition and shorter than 3 min on the two components has not been described as yet, and the interaction between lag length and familiarity is unclear. The current experiment aims to address these issues. In this experiment, famous and unfamiliar faces were represented after short, medium, or long lags, and participants were required to decide whether each face was known or not. The data showed that the frontal N250r, rather than the temporal counterpart, persisted to the medium lag case for famous faces; for unfamiliar faces, no N250r was observed. The frontal N400 was more regulated by lag length than the centroparietal counterpart. These results suggest that the frontal N250r and the frontal N400 are affected by the lag length; moreover, the former is more sensitive to the pre-experimental familiarity of faces.

Physiological assessment and path coefficient analysis to improve evaluation of alfalfa autotoxicity.

PubMed

Chon, Sang-Uk; Nelson, C Jerry; Coutts, John H

2003-11-01

Reseeding of alfalfa is affected until autotoxic chemicals break down or are dispersed, often requiring a year or more. Bioassays of seed germination and early seedling growth, on agar medium in petri dishes, were conducted to evaluate autotoxic responses of 20 alfalfa germplasms to water-soluble extracts of alfalfa leaf tissue. Root length, 120 hr after placing imbibed seed on agar, was more sensitive to the autotoxin(s) than was hypocotyl length, germination speed, and final germination percentage. Path coefficient analyses showed variation in root length had 7-17 times more effect than variation in hypocotyl length in determining autotoxic effects on total seedling length. Although variations in seed size and germination rate were negatively associated (P < 0.05) with final root length, the autotoxin had little effect on these factors relative to that on root length. Germplasms in the control differed (P < 0.05) in root length, requiring tolerance to be evaluated as percent of control. Germplasms, as percent of control, differed significantly (P < 0.05) at extract concentrations of 1.0 and 4.0 g l(-1), but the range and LSD were more favorable for selection at 1.0 g l(-1). Root length is appropriate for genetic assessments of tolerance to the autotoxin when expressed as percent of control.

Human papillomavirus type 56 polymorphism in Canadian women with and without cervical lesions.

PubMed

Rodrigues-Coutlée, Catherine; Archambault, Jacques; Money, Deborah; Ramanakumar, Agnihotram V; Raboud, Janet; Hankins, Catherine; Koushik, Anita; Richardson, Harriet; Brassard, Paul; Franco, Eduardo L; Coutlée, Francois

2013-12-01

The genomic diversity of high-risk human papillomaviruses (HPV) has been associated with viral persistence and HPV-induced lesions. Studies on HPV56 persistence are still pending. To assess the association between HPV56 polymorphism and HPV56 persistence and presence of high-grade cervical intraepithelial neoplasia (CIN2,3) or cancer. HPV56-positive cervical specimens from 204 women selected from a total of 4669 participants recruited in 5 epidemiological studies (parent studies) were further analyzed by PCR-sequencing of the long control region (LCR). Of the 81 women followed prospectively in cohort studies who could be classified, 34 had persistent and 47 had transient HPV56 infections. Variant HPV56-LCR-MTL-21 was detected more frequently in persistent infections (52.9%, 95% CI: 36.7-68.6%) than in transient infections (25.5%, 95% CI: 15.1-39.4). Considering only women recruited in a cohort of women infected or at high risk for HIV infection, infection with variant HPV56-LCR-MTL-21 (OR=4.4, 95% CI: 1.3-14.5) was significantly associated with HPV56 persistence controlling in multivariate analysis for high risk HPV detection and HIV infection. A variation at nucleotide 7800 in HPV56-LCR-MTL-21 resulted in the loss of a binding site for Elf-1 embedded in one of the E2 binding sites, a potential activator or repressor of expression of the HPV genome. HPV56 polymorphism was not associated with CIN2,3 or cancer in women enrolled in cross-sectional and case-control studies. Polymorphism in HPV56 may influence the risk that infections with this type will persist. Copyright © 2013 Elsevier B.V. All rights reserved.

Prefrontal and Parietal Correlates of Cognitive Control Related to the Adult Outcome of Attention-Deficit/Hyperactivity Disorder Diagnosed in Childhood

PubMed Central

Schulz, Kurt P.; Li, Xiaobo; Clerkin, Suzanne M.; Fan, Jin; Berwid, Olga G.; Newcorn, Jeffrey H.; Halperin, Jeffrey M.

2017-01-01

The protracted and highly variable development of prefrontal cortex regions that support cognitive control has been purported to shape the adult outcome of attention-deficit/hyperactivity disorder (ADHD). This neurodevelopmental model was tested in a prospectively followed sample of 27 adult probands who were diagnosed with ADHD in childhood and 28 carefully matched comparison subjects aged 21 – 28 years. Probands were classified with persistent ADHD or remitted ADHD. Behavioral and neural responses to the stimulus and response conflict task performed during functional magnetic resonance imaging were compared in probands and comparison subjects and in probands with persistent and remitted ADHD. Response speed and accuracy for stimulus, response, and combined conflicts did not differ across groups. Orbitofrontal, inferior frontal and parietal activation was lower in probands than comparison subjects, but only for combined conflicts, when demand for cognitive control was highest. Reduced activation for combined conflicts in probands was almost wholly attributable to the persistence of ADHD; orbitofrontal, inferior frontal, anterior cingulate and parietal activation was lower in probands with persistent ADHD than both probands with remitted ADHD and comparison subjects, but did not differ between probands with remitted ADHD and comparison subjects. These data provide the first evidence that prefrontal and parietal activation during cognitive control parallels the adult outcome of ADHD diagnosed in childhood, with persistence of symptoms linked to reduced activation and symptom recovery associated with activation indistinguishable from adults with no history of ADHD. PMID:28292705

Intraflagellar transport particle size scales inversely with flagellar length: revisiting the balance-point length control model.

PubMed

Engel, Benjamin D; Ludington, William B; Marshall, Wallace F

2009-10-05

The assembly and maintenance of eukaryotic flagella are regulated by intraflagellar transport (IFT), the bidirectional traffic of IFT particles (recently renamed IFT trains) within the flagellum. We previously proposed the balance-point length control model, which predicted that the frequency of train transport should decrease as a function of flagellar length, thus modulating the length-dependent flagellar assembly rate. However, this model was challenged by the differential interference contrast microscopy observation that IFT frequency is length independent. Using total internal reflection fluorescence microscopy to quantify protein traffic during the regeneration of Chlamydomonas reinhardtii flagella, we determined that anterograde IFT trains in short flagella are composed of more kinesin-associated protein and IFT27 proteins than trains in long flagella. This length-dependent remodeling of train size is consistent with the kinetics of flagellar regeneration and supports a revised balance-point model of flagellar length control in which the size of anterograde IFT trains tunes the rate of flagellar assembly.

An atypical bHLH protein encoded by POSITIVE REGULATOR OF GRAIN LENGTH 2 is involved in controlling grain length and weight of rice through interaction with a typical bHLH protein APG.

PubMed

Heang, Dany; Sassa, Hidenori

2012-06-01

Grain size is an important yield component in rice, however, genes controlling the trait remain poorly understood. Previously, we have shown that an antagonistic pair of basic helix-loop-helix (bHLH) proteins, POSITIVE REGULATOR OF GRAIN LENGTH 1 (PGL1) and ANTAGONIST OF PGL1 (APG), is involved in controlling rice grain length. Here, we report the involvement of another atypical bHLH protein gene, POSITIVE REGULATOR OF GRAIN LENGTH 2 (PGL2), in the regulation of rice grain length. Over-expression of PGL2 in the lemma/palea increased grain length and weight in correlation with the level of transgene expression. Observation of the inner epidermal cells of lemma of PGL2-overexpressing lines revealed that the long grain size is caused by an increase in cell length. PGL2 interacts with a typical bHLH protein APG, a negative regulator of rice grain length and weight, in vitro and in vivo. It was reported that overexpression of BU1 (BRASSINOSTEROID UPREGULATED 1), the closest homolog of PGL2, caused an increase in grain length. However, we detected no interaction between BU1 and APG. These findings suggest that PGL2 and PGL1 redundantly suppress the function of APG by forming heterodimers to positively regulate the rice grain length, while the pathway through which BU1, the closest homolog of PGL2, controls grain length is independent of APG.

An atypical bHLH protein encoded by POSITIVE REGULATOR OF GRAIN LENGTH 2 is involved in controlling grain length and weight of rice through interaction with a typical bHLH protein APG

PubMed Central

Heang, Dany; Sassa, Hidenori

2012-01-01

Grain size is an important yield component in rice, however, genes controlling the trait remain poorly understood. Previously, we have shown that an antagonistic pair of basic helix-loop-helix (bHLH) proteins, POSITIVE REGULATOR OF GRAIN LENGTH 1 (PGL1) and ANTAGONIST OF PGL1 (APG), is involved in controlling rice grain length. Here, we report the involvement of another atypical bHLH protein gene, POSITIVE REGULATOR OF GRAIN LENGTH 2 (PGL2), in the regulation of rice grain length. Over-expression of PGL2 in the lemma/palea increased grain length and weight in correlation with the level of transgene expression. Observation of the inner epidermal cells of lemma of PGL2-overexpressing lines revealed that the long grain size is caused by an increase in cell length. PGL2 interacts with a typical bHLH protein APG, a negative regulator of rice grain length and weight, in vitro and in vivo. It was reported that overexpression of BU1 (BRASSINOSTEROID UPREGULATED 1), the closest homolog of PGL2, caused an increase in grain length. However, we detected no interaction between BU1 and APG. These findings suggest that PGL2 and PGL1 redundantly suppress the function of APG by forming heterodimers to positively regulate the rice grain length, while the pathway through which BU1, the closest homolog of PGL2, controls grain length is independent of APG. PMID:23136524

Generalized theory of semiflexible polymers.

PubMed

Wiggins, Paul A; Nelson, Philip C

2006-03-01

DNA bending on length scales shorter than a persistence length plays an integral role in the translation of genetic information from DNA to cellular function. Quantitative experimental studies of these biological systems have led to a renewed interest in the polymer mechanics relevant for describing the conformational free energy of DNA bending induced by protein-DNA complexes. Recent experimental results from DNA cyclization studies have cast doubt on the applicability of the canonical semiflexible polymer theory, the wormlike chain (WLC) model, to DNA bending on biologically relevant length scales. This paper develops a theory of the chain statistics of a class of generalized semiflexible polymer models. Our focus is on the theoretical development of these models and the calculation of experimental observables. To illustrate our methods, we focus on a specific, illustrative model of DNA bending. We show that the WLC model generically describes the long-length-scale chain statistics of semiflexible polymers, as predicted by renormalization group arguments. In particular, we show that either the WLC or our present model adequately describes force-extension, solution scattering, and long-contour-length cyclization experiments, regardless of the details of DNA bend elasticity. In contrast, experiments sensitive to short-length-scale chain behavior can in principle reveal dramatic departures from the linear elastic behavior assumed in the WLC model. We demonstrate this explicitly by showing that our toy model can reproduce the anomalously large short-contour-length cyclization factors recently measured by Cloutier and Widom. Finally, we discuss the applicability of these models to DNA chain statistics in the context of future experiments.

Interspecific variation in persistence of buried weed seeds follows trade-offs among physiological, chemical, and physical seed defenses.

PubMed

Davis, Adam S; Fu, Xianhui; Schutte, Brian J; Berhow, Mark A; Dalling, James W

2016-10-01

Soil seedbanks drive infestations of annual weeds, yet weed management focuses largely on seedling mortality. As weed seedbanks increasingly become reservoirs of herbicide resistance, species-specific seedbank management approaches will be essential to weed control. However, the development of seedbank management strategies can only develop from an understanding of how seed traits affect persistence.We quantified interspecific trade-offs among physiological, chemical, and physical traits of weed seeds and their persistence in the soil seedbank in a common garden study. Seeds of 11 annual weed species were buried in Savoy, IL, from 2007 through 2012. Seedling recruitment was measured weekly and seed viability measured annually. Seed physiological (dormancy), chemical (phenolic compound diversity and concentration; invertebrate toxicity), and physical traits (seed coat mass, thickness, and rupture resistance) were measured.Seed half-life in the soil ( t 0.5 ) showed strong interspecific variation ( F 10,30  = 15, p  < .0001), ranging from 0.25 years ( Bassia scoparia ) to 2.22 years ( Abutilon theophrasti ). Modeling covariances among seed traits and seedbank persistence quantified support for two putative defense syndromes (physiological-chemical and physical-chemical) and highlighted the central role of seed dormancy in controlling seed persistence.A quantitative comparison between our results and other published work indicated that weed seed dormancy and seedbank persistence are linked across diverse environments and agroecosystems. Moreover, among seedbank-forming early successional plant species, relative investment in chemical and physical seed defense varies with seedbank persistence. Synthesis and applications . Strong covariance among weed seed traits and persistence in the soil seedbank indicates potential for seedbank management practices tailored to specific weed species. In particular, species with high t 0.5 values tend to invest less in chemical defenses. This makes them highly vulnerable to physical harvest weed seed control strategies, with small amounts of damage resulting in their full decay.

Antenna Mechanism of Length Control of Actin Cables

PubMed Central

Mohapatra, Lishibanya; Goode, Bruce L.; Kondev, Jane

2015-01-01

Actin cables are linear cytoskeletal structures that serve as tracks for myosin-based intracellular transport of vesicles and organelles in both yeast and mammalian cells. In a yeast cell undergoing budding, cables are in constant dynamic turnover yet some cables grow from the bud neck toward the back of the mother cell until their length roughly equals the diameter of the mother cell. This raises the question: how is the length of these cables controlled? Here we describe a novel molecular mechanism for cable length control inspired by recent experimental observations in cells. This “antenna mechanism” involves three key proteins: formins, which polymerize actin, Smy1 proteins, which bind formins and inhibit actin polymerization, and myosin motors, which deliver Smy1 to formins, leading to a length-dependent actin polymerization rate. We compute the probability distribution of cable lengths as a function of several experimentally tuneable parameters such as the formin-binding affinity of Smy1 and the concentration of myosin motors delivering Smy1. These results provide testable predictions of the antenna mechanism of actin-cable length control. PMID:26107518

Antenna Mechanism of Length Control of Actin Cables.

PubMed

Mohapatra, Lishibanya; Goode, Bruce L; Kondev, Jane

2015-06-01

Actin cables are linear cytoskeletal structures that serve as tracks for myosin-based intracellular transport of vesicles and organelles in both yeast and mammalian cells. In a yeast cell undergoing budding, cables are in constant dynamic turnover yet some cables grow from the bud neck toward the back of the mother cell until their length roughly equals the diameter of the mother cell. This raises the question: how is the length of these cables controlled? Here we describe a novel molecular mechanism for cable length control inspired by recent experimental observations in cells. This "antenna mechanism" involves three key proteins: formins, which polymerize actin, Smy1 proteins, which bind formins and inhibit actin polymerization, and myosin motors, which deliver Smy1 to formins, leading to a length-dependent actin polymerization rate. We compute the probability distribution of cable lengths as a function of several experimentally tuneable parameters such as the formin-binding affinity of Smy1 and the concentration of myosin motors delivering Smy1. These results provide testable predictions of the antenna mechanism of actin-cable length control.

Deficits in heel-rise height and achilles tendon elongation occur in patients recovering from an Achilles tendon rupture.

PubMed

Silbernagel, Karin Grävare; Steele, Robert; Manal, Kurt

2012-07-01

Whether an Achilles tendon rupture is treated surgically or not, complications such as muscle weakness, decrease in heel-rise height, and gait abnormalities persist after injury. The purpose of this study was to evaluate if side-to-side differences in maximal heel-rise height can be explained by differences in Achilles tendon length. Case series; level of evidence, 4. Eight patients (mean [SD] age of 46 [13] years) with acute Achilles tendon rupture and 10 healthy subjects (mean [SD] age of 28 [8] years) were included in the study. Heel-rise height, Achilles tendon length, and patient-reported outcome were measured 3, 6, and 12 months after injury. Achilles tendon length was evaluated using motion analysis and ultrasound imaging. The Achilles tendon length test-retest reliability (intraclass correlation coefficient = 0.97) was excellent. For the healthy subjects, there were no side-to-side differences in tendon length and heel-rise height. Patients with Achilles tendon ruptures had significant differences between the injured and uninjured side for both tendon length (mean [SD] difference, 2.6-3.1 [1.2-1.4] cm, P = .017-.028) and heel-rise height (mean [SD] difference, -4.1 to -6.1 [1.7-1.8] cm, P = .012-.028). There were significant negative correlations (r = -0.943, P = .002, and r = -0.738, P = .037) between the side-to-side difference in heel-rise height and Achilles tendon length at the 6- and 12-month evaluations, respectively. The side-to-side difference found in maximal heel-rise height can be explained by a difference in Achilles tendon length in patients recovering from an Achilles tendon rupture. Minimizing tendon elongation appears to be an important treatment goal when aiming for full return of function.

Cross-sectional Associations between Exposure to Persistent Organic Pollutants and Leukocyte Telomere Length among U.S. Adults in NHANES, 2001–2002

PubMed Central

Mitro, Susanna D.; Birnbaum, Linda S.; Needham, Belinda L.; Zota, Ami R.

2015-01-01

Background: Exposure to persistent organic pollutants (POPs) such as dioxins, furans, and polychlorinated biphenyls (PCBs) may influence leukocyte telomere length (LTL), a biomarker associated with chronic disease. In vitro research suggests dioxins may bind to the aryl hydrocarbon receptor (AhR) and induce telomerase activity, which elongates LTL. However, few epidemiologic studies have investigated associations between POPs and LTL. Objectives: We examined the association between 18 PCBs, 7 dioxins, and 9 furans and LTL among 1,330 U.S. adults from NHANES 2001–2002. Methods: We created three summed POP metrics based on toxic equivalency factor (TEF), a potency measure including affinity for the AhR: a) non–dioxin-like PCBs (composed of 10 non–dioxin-like PCBs; no AhR affinity and no TEF); b) non-ortho PCBs (composed of 2 non–ortho-substituted PCBs with high TEFs); and c) toxic equivalency (TEQ) (composed of 7 dioxins, 9 furans, 2 non–ortho-substituted PCBs, and 6 mono–ortho-substituted PCBs; weighted by TEF). We tested the association between each metric and LTL using linear regression, adjusting for demographics, blood cell count and distribution, and another metric with a different TEF (i.e., non-ortho PCBs and TEQ adjusted for non–dioxin-like PCBs; non–dioxin-like PCBs adjusted for non-ortho PCBs). Results: In adjusted models, each doubling of serum concentrations of non-ortho PCBs and TEQ was associated with 3.74% (95% CI: 2.10, 5.40) and 5.29% (95% CI: 1.66, 9.05) longer LTLs, respectively. Compared with the lowest quartile, the highest quartile of exposure was associated with 9.16% (95% CI: 2.96, 15.73) and 7.84% (95% CI: –0.53, 16.92) longer LTLs, respectively. Non–dioxin-like PCBs were not associated with LTL. Conclusions: POPs with high TEFs and AhR affinity were associated with longer LTL. Because many dioxin-associated cancers are also associated with longer LTL, these results may provide insight into the mechanisms underlying PCB- and dioxin-related carcinogenesis. Citation: Mitro SD, Birnbaum LS, Needham BL, Zota AR. 2016. Cross-sectional associations between exposure to persistent organic pollutants and leukocyte telomere length among U.S. adults in NHANES, 2001–2002. Environ Health Perspect 124:651–658; http://dx.doi.org/10.1289/ehp.1510187 PMID:26452299

Influences of Teachers' Attitudes and Oral Guidance on the Persistence of Young Children Aged 3-6 Years Old

ERIC Educational Resources Information Center

Dan, Fei; Feng, Lu; Wang, Qiong

2009-01-01

Persistence is important in developing pre-school children's ego control. Based on the fact that during the teaching process a teacher's communication and actions will have a significant influence on young children, which is due to the teachers' high degree of control over them, four experiments were designed to probe the influences of teachers'…

A gap analysis approach to assess patient persistence with glaucoma medication.

PubMed

Lee, Paul P; Walt, John G; Chiang, Tina H; Guckian, Angela; Keener, John

2007-10-01

To develop an alternative method for analysis of patient persistence with prescribed medications using the prostaglandin class of intraocular pressure (IOP)-lowering drugs as a model. A retrospective study of prescription refill patterns. Patients with a pharmacy claim for a 2.5 ml bottle of latanoprost, travoprost, or bimatoprost between September 1, 2002 and December 31, 2002 were identified from a retail pharmacy database and were followed up for 12 months. Three separate analyses defined gaps in therapy as spans in excess of 45, 60, or 120 days without a refill for the same medication. Patients were categorized by the number of gaps in therapy and the cumulative length of gaps. A Kaplan-Meier analysis was conducted using a 120-day allowable refill period. For refill periods of 45, 60, and 120 days, 10.6%, 28.6%, and 77.5% of patients, respectively, had no gaps in therapy, and 32.6%, 53.4%, and 86.5%, respectively, had 30 days or fewer off therapy annually. According to the 45-day threshold analysis, 50.7% of patients had three or more gaps vs 18.5% in the 60-day analysis and none in the 120-day analysis. The Kaplan-Meier curve shows 88.6% and 76.1% of patients were persistent for 120 days and one year, respectively. Compared with Kaplan-Meier survival curves, the gap analysis approach may better parallel clinical experience with patient persistence, in which patients stop and restart medications for a variety of reasons over time. This method also may help to identify avenues for investigation of lack of persistency among many patients.

Predicting Factors for High-Grade Cervical Dysplasia in Women With Low-Grade Cervical Cytology and Nonvisible Squamocolumnar Junction.

PubMed

Bogani, Giorgio; Taverna, Francesca; Lombardo, Claudia; Ditto, Antonino; Martinelli, Fabio; Signorelli, Mauro; Chiappa, Valentina; Leone Roberti Maggiore, U; Mosca, Lavinia; Sabatucci, Ilaria; Scaffa, Cono; Lorusso, Domenica; Raspagliesi, Francesco

2018-01-01

To assess the risk of developing high-grade cervical dysplasia among women with low-grade cervical cytology and nonvisible squamocolumnar junction (SCJ) at colposcopic examination. Data of consecutive women with low-grade intraepithelial lesion(≤LSIL) undergoing colposcopic examination, which was unsatisfactory (due to the lack of the visualization of the entire SCJ), were retrospectively reviewed. The risk of developing high-grade cervical intraepithelial neoplasia (CIN2+) was assessed using Kaplan-Meier and Cox models. Data of 86 women were retrieved. Mean (standard deviation [SD]) age was 36.3 (13.4) years. A total of 71 (82.5%) patients had high-risk human papillomavirus (HR-HPV) at the time of diagnosis. Among the 63 patients undergoing repetition of HPV testing, 15 (24%) and 48 (76%) women had positive and negative tests for HR-HPV at 12 months, respectively. We observed that 5 (33%) of 15 patients with HPV persistence developed CIN2+, while only 1 (2%) patient of 48 patients without HPV persistence developed CIN2+ (odds ratio [OR]: 23.5; 95% confidence interval [CI]: 2.46-223.7; P < .001). The length of HR-HPV persistence correlated with an increased risk of developing CIN2+ ( P < .001; P for trend). High-risk HPV persistence is the only factor predicting for CIN2+ (hazard ratio: 3.19; 95% CI: 1.55-6.57; P = .002). High-risk HPV persistence predicts the risk of developing CIN2+ in patients with unsatisfactory colposcopic examination. Further studies are warranted in order to implement the use of HPV testing in patients with unsatisfactory colposcopy.

Selective peripheral nerve resection for treatment of persistent pain around the knee joint after total knee arthroplasty.

PubMed

Zhong, Guangjun; Liang, Zhu; Kan, Jiang; Muheremu, Aikeremujiang

2018-01-01

Objective This study was performed to determine the efficacy of selective peripheral nerve resection for treatment of persistent neuropathic pain after total knee arthroplasty (TKA). Methods Patients who underwent TKA in our department from January 2013 to July 2016 and experienced persistent pain around the knee joint after TKA were retrospectively included in the current study. Sixty patients were divided into experimental and control groups according the treatment they received. The treatment effect was evaluated by the Hospital for Special Surgery (HSS) knee score and visual analog scale (VAS) pain score preoperatively and at 1, 2, 3, 6, and 12 months postoperatively. Results The HSS knee scores were higher in both groups after than before the treatment, and HSS knee scores were significantly higher in the experimental group than in the control group. The VAS pain scores were lower in both groups after than before the treatment, and VAS pain scores were significantly lower in the experimental group than in the control group. Conclusions Selective peripheral nerve resection is an effective treatment method for persistent neuropathic pain after TKA.

Impact of myxomatosis in relation to local persistence in wild rabbit populations: the role of waning immunity and the reproductive period.

PubMed

Fouchet, David; Guitton, Jean-Sébastien; Marchandeau, Stéphane; Pontier, Dominique

2008-02-21

Many diseases are less severe when they are contracted in early life. For highly lethal diseases, such as myxomatosis in rabbits, getting infected early in life can represent the best chance for an individual to survive the disease. For myxomatosis, early infections are attenuated by maternal antibodies. This may lead to the immunisation of the host, preventing the subsequent development of the lethal form of the disease. But early infection of young individuals requires specific demographic and epidemiological contexts, such as a high transmission rate of the pathogen agent. To investigate other factors involved in the impact of such diseases, we have built a stochastic model of a rabbit metapopulation infected by myxomatosis. We show that the impact of the pathogen agent can be reduced by early infections only when the agent has a long local persistence time and/or when the host subpopulations are highly connected. The length of the reproductive period and the duration of acquired immunity are also important factors influencing the persistence of the pathogen and thus, the impact of the disease. Besides confirming the role of classical factors in the persistence of a pathogen agent, such as the size of the subpopulation or the degree of connectivity, our results highlight novel factors that can modulate the impact of diseases whose severity increase with age.

Self-reported post-exertional fatigue in Gulf War veterans: roles of autonomic testing

PubMed Central

Li, Mian; Xu, Changqing; Yao, Wenguo; Mahan, Clare M.; Kang, Han K.; Sandbrink, Friedhelm; Zhai, Ping; Karasik, Pamela A.

2014-01-01

To determine if objective evidence of autonomic dysfunction exists from a group of Gulf War veterans with self-reported post-exertional fatigue, we evaluated 16 Gulf War ill veterans and 12 Gulf War controls. Participants of the ill group had self- reported, unexplained chronic post-exertional fatigue and the illness symptoms had persisted for years until the current clinical study. The controls had no self-reported post-exertional fatigue either at the time of initial survey nor at the time of the current study. We intended to identify clinical autonomic disorders using autonomic and neurophysiologic testing in the clinical context. We compared the autonomic measures between the 2 groups on cardiovascular function at both baseline and head-up tilt, and sudomotor function. We identified 1 participant with orthostatic hypotension, 1 posture orthostatic tachycardia syndrome, 2 distal small fiber neuropathy, and 1 length dependent distal neuropathy affecting both large and small fiber in the ill group; whereas none of above definable diagnoses was noted in the controls. The ill group had a significantly higher baseline heart rate compared to controls. Compound autonomic scoring scale showed a significant higher score (95% CI of mean: 1.72–2.67) among ill group compared to controls (0.58–1.59). We conclude that objective autonomic testing is necessary for the evaluation of self-reported, unexplained post-exertional fatigue among some Gulf War veterans with multi-symptom illnesses. Our observation that ill veterans with self-reported post-exertional fatigue had objective autonomic measures that were worse than controls warrants validation in a larger clinical series. PMID:24431987

Eye-Hand Coordination during Visuomotor Adaptation with Different Rotation Angles

PubMed Central

Rentsch, Sebastian; Rand, Miya K.

2014-01-01

This study examined adaptive changes of eye-hand coordination during a visuomotor rotation task. Young adults made aiming movements to targets on a horizontal plane, while looking at the rotated feedback (cursor) of hand movements on a monitor. To vary the task difficulty, three rotation angles (30°, 75°, and 150°) were tested in three groups. All groups shortened hand movement time and trajectory length with practice. However, control strategies used were different among groups. The 30° group used proportionately more implicit adjustments of hand movements than other groups. The 75° group used more on-line feedback control, whereas the 150° group used explicit strategic adjustments. Regarding eye-hand coordination, timing of gaze shift to the target was gradually changed with practice from the late to early phase of hand movements in all groups, indicating an emerging gaze-anchoring behavior. Gaze locations prior to the gaze anchoring were also modified with practice from the cursor vicinity to an area between the starting position and the target. Reflecting various task difficulties, these changes occurred fastest in the 30° group, followed by the 75° group. The 150° group persisted in gazing at the cursor vicinity. These results suggest that the function of gaze control during visuomotor adaptation changes from a reactive control for exploring the relation between cursor and hand movements to a predictive control for guiding the hand to the task goal. That gaze-anchoring behavior emerged in all groups despite various control strategies indicates a generality of this adaptive pattern for eye-hand coordination in goal-directed actions. PMID:25333942

Leukocyte telomere length and depression, anxiety and stress and adjustment disorders in primary health care patients.

PubMed

Wang, Xiao; Sundquist, Kristina; Hedelius, Anna; Palmér, Karolina; Memon, Ashfaque A; Sundquist, Jan

2017-04-24

The primary aim was to examine possible differences in telomere length between primary health care patients, with depression, anxiety or stress and adjustment disorders, and healthy controls. The second aim was to examine the association between telomere length and baseline characteristics in the patients. The third aim was to examine the potential effects of the 8-week treatments (mindfulness-based group therapy or treatment as usual, i.e. mostly cognitive-based therapy) on telomere length, and to examine whether there was a difference in the potential effect on telomere length between the two groups. A total of 501 individuals including 181 patients (aged 20-64 years), with depression, anxiety and stress and adjustment disorders, and 320 healthy controls (aged 19-70 years) were recruited in the study. Patient data were collected from a randomized controlled trial comparing mindfulness-based group therapy with treatment as usual. We isolated genomic DNA from blood samples, collected at baseline and after the 8-week follow-up. Telomere length was measured by quantitative real-time (qRT)-PCR. Telomere length was significantly shorter in the patients (mean = 0.77 ± 0.12,), compared to the controls (mean = 0.81 ± 0.14) (p = 0.006). The difference in telomere length remained significant after controlling for age and sex. Old age, male sex and being overweight were associated with shorter telomere length. There was no significant difference in telomere length between baseline and at the 8-week follow-up in any of the treatment groups and no difference between the two groups. Our findings confirm that telomere length, as compared with healthy controls, is shortened in patients with depression, anxiety and stress and adjustment disorders. In both groups (mindfulness-based group therapy or treatment as usual), the telomere length remained unchanged after the 8-week treatment/follow-up and there was no difference between the two groups. (ClinicalTrials.gov ID: NCT01476371 ) Registered November 11, 2011.

A role for the non-canonical Wnt-ß-Catenin and TGF-ß signaling pathways in the induction of tolerance during the establishment of a Salmonella enterica serovar Enteritidis persistent cecal infection in chickens

USDA-ARS?s Scientific Manuscript database

Non-typhoidal Salmonella enterica induce an early pro-inflammatory response in chickens. However, the response is short-lived, asymptomatic of disease, resulting in a persistent colonization of the ceca, and fecal shedding of bacteria. The underlying mechanisms that control this persistent infecti...

RegA Plays a Key Role in Oxygen-Dependent Establishment of Persistence and in Isocitrate Lyase Activity, a Critical Determinant of In vivo Brucella suis Pathogenicity

PubMed Central

Abdou, Elias; Jiménez de Bagüés, María P.; Martínez-Abadía, Ignacio; Ouahrani-Bettache, Safia; Pantesco, Véronique; Occhialini, Alessandra; Al Dahouk, Sascha; Köhler, Stephan; Jubier-Maurin, Véronique

2017-01-01

For aerobic human pathogens, adaptation to hypoxia is a critical factor for the establishment of persistent infections, as oxygen availability is low inside the host. The two-component system RegB/A of Brucella suis plays a central role in the control of respiratory systems adapted to oxygen deficiency, and in persistence in vivo. Using an original “in vitro model of persistence” consisting in gradual oxygen depletion, we compared transcriptomes and proteomes of wild-type and ΔregA strains to identify the RegA-regulon potentially involved in the set-up of persistence. Consecutive to oxygen consumption resulting in growth arrest, 12% of the genes in B. suis were potentially controlled directly or indirectly by RegA, among which numerous transcriptional regulators were up-regulated. In contrast, genes or proteins involved in envelope biogenesis and in cellular division were repressed, suggesting a possible role for RegA in the set-up of a non-proliferative persistence state. Importantly, the greatest number of the RegA-repressed genes and proteins, including aceA encoding the functional IsoCitrate Lyase (ICL), were involved in energy production. A potential consequence of this RegA impact may be the slowing-down of the central metabolism as B. suis progressively enters into persistence. Moreover, ICL is an essential determinant of pathogenesis and long-term interactions with the host, as demonstrated by the strict dependence of B. suis on ICL activity for multiplication and persistence during in vivo infection. RegA regulates gene or protein expression of all functional groups, which is why RegA is a key regulator of B. suis in adaptation to oxygen depletion. This function may contribute to the constraint of bacterial growth, typical of chronic infection. Oxygen-dependent activation of two-component systems that control persistence regulons, shared by several aerobic human pathogens, has not been studied in Brucella sp. before. This work therefore contributes significantly to the unraveling of persistence mechanisms in this important zoonotic pathogen. PMID:28573107

Micromechanics of an Extrusion in High-Cycle Fatigue

DTIC Science & Technology

1988-08-22

length of R would be longer than the slot by an amount referred to as the "static extrusion" by Mughrabi et al . (1983). This e,,. causes an initial... Mughrabi (1980) in their studies of persistent slip bands. Extrusions and intru- sions in fatigue specimens were also observed by a number of other...interstitial dislocation dipoles, and a negative e("i by vacancy dipoles. Recently, Antoncpoulus, Brown and Winter (1976) and Mughrabi , Wang, Differt and

Fracture controls on valley persistence: the Cairngorm Granite pluton, Scotland

NASA Astrophysics Data System (ADS)

Hall, A. M.; Gillespie, M. R.

2017-09-01

Valleys are remarkably persistent features in many different tectonic settings, but the reasons for this persistence are rarely explored. Here, we examine the structural controls on valleys in the Cairngorms Mountains, Scotland, part of the passive margin of the eastern North Atlantic. We consider valleys at three scales: straths, glens and headwater valleys. The structural controls on valleys in and around the Cairngorm Granite pluton were examined on satellite and aerial photographs and by field survey. Topographic lineaments, including valleys, show no consistent orientation with joint sets or with sheets of microgranite and pegmatitic granite. In this granite landscape, jointing is not a first-order control on valley development. Instead, glens and headwater valleys align closely to quartz veins and linear alteration zones (LAZs). LAZs are zones of weakness in the granite pluton in which late-stage hydrothermal alteration and hydro-fracturing have greatly reduced rock mass strength and increased permeability. LAZs, which can be kilometres long and >700 m deep, are the dominant controls on the orientation of valleys in the Cairngorms. LAZs formed in the roof zone of the granite intrusion. Although the Cairngorm pluton was unroofed soon after emplacement, the presence of Old Red Sandstone (ORS) outliers in the terrain to the north and east indicates that the lower relief of the sub-ORS basement surface has been lowered by <500 m. Hence, the valley patterns in and around the Cairngorms have persisted through >1 km of vertical erosion and for 400 Myr. This valley persistence is a combined product of regionally low rates of basement exhumation and of the existence of LAZs in the Cairngorm pluton and sub-parallel Caledonide fractures in the surrounding terrain with depths that exceed 1 km.

Terrestrial Planet Finder cryogenic delay line development

NASA Technical Reports Server (NTRS)

Smythe, Robert F.; Swain, Mark R.; Alvarez-Salazar, Oscar; Moore, James D.

2004-01-01

Delay lines provide the path-length compensation that makes the measurement of interference fringes possible. When used for nulling interferometry, the delay line must control path-lengths so that the null is stable and controlled throughout the measurement. We report on a low noise, low disturbance, and high bandwidth optical delay line capable of meeting the TPF interferometer optical path length control requirements at cryogenic temperatures.

Altering attentional control settings causes persistent biases of visual attention.

PubMed

Knight, Helen C; Smith, Daniel T; Knight, David C; Ellison, Amanda

2016-01-01

Attentional control settings have an important role in guiding visual behaviour. Previous work within cognitive psychology has found that the deployment of general attentional control settings can be modulated by training. However, research has not yet established whether long-term modifications of one particular type of attentional control setting can be induced. To address this, we investigated persistent alterations to feature search mode, also known as an attentional bias, towards an arbitrary stimulus in healthy participants. Subjects were biased towards the colour green by an information sheet. Attentional bias was assessed using a change detection task. After an interval of either 1 or 2 weeks, participants were then retested on the same change detection task, tested on a different change detection task where colour was irrelevant, or were biased towards an alternative colour. One experiment included trials in which the distractor stimuli (but never the target stimuli) were green. The key finding was that green stimuli in the second task attracted attention, despite this impairing task performance. Furthermore, inducing a second attentional bias did not override the initial bias toward green objects. The attentional bias also persisted for at least two weeks. It is argued that this persistent attentional bias is mediated by a chronic change to participants' attentional control settings, which is aided by long-term representations involving contextual cueing. We speculate that similar changes to attentional control settings and continuous cueing may relate to attentional biases observed in psychopathologies. Targeting these biases may be a productive approach to treatment.

Evolving Systems: An Outcome of Fondest Hopes and Wildest Dreams

NASA Technical Reports Server (NTRS)

Frost, Susan A.; Balas, Mark J.

2012-01-01

New theory is presented for evolving systems, which are autonomously controlled subsystems that self-assemble into a new evolved system with a higher purpose. Evolving systems of aerospace structures often require additional control when assembling to maintain stability during the entire evolution process. This is the concept of Adaptive Key Component Control that operates through one specific component to maintain stability during the evolution. In addition, this control must often overcome persistent disturbances that occur while the evolution is in progress. Theoretical results will be presented for Adaptive Key Component control for persistent disturbance rejection. An illustrative example will demonstrate the Adaptive Key Component controller on a system composed of rigid body and flexible body modes.

Modeling Protein Excited-state Structures from "Over-length" Chemical Cross-links.

PubMed

Ding, Yue-He; Gong, Zhou; Dong, Xu; Liu, Kan; Liu, Zhu; Liu, Chao; He, Si-Min; Dong, Meng-Qiu; Tang, Chun

2017-01-27

Chemical cross-linking coupled with mass spectroscopy (CXMS) provides proximity information for the cross-linked residues and is used increasingly for modeling protein structures. However, experimentally identified cross-links are sometimes incompatible with the known structure of a protein, as the distance calculated between the cross-linked residues far exceeds the maximum length of the cross-linker. The discrepancies may persist even after eliminating potentially false cross-links and excluding intermolecular ones. Thus the "over-length" cross-links may arise from alternative excited-state conformation of the protein. Here we present a method and associated software DynaXL for visualizing the ensemble structures of multidomain proteins based on intramolecular cross-links identified by mass spectrometry with high confidence. Representing the cross-linkers and cross-linking reactions explicitly, we show that the protein excited-state structure can be modeled with as few as two over-length cross-links. We demonstrate the generality of our method with three systems: calmodulin, enzyme I, and glutamine-binding protein, and we show that these proteins alternate between different conformations for interacting with other proteins and ligands. Taken together, the over-length chemical cross-links contain valuable information about protein dynamics, and our findings here illustrate the relationship between dynamic domain movement and protein function. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Leukocyte telomere length and diabetes status, duration, and control: the 1999-2002 National Health and Nutrition Examination Survey.

PubMed

Menke, Andy; Casagrande, Sarah; Cowie, Catherine C

2015-09-29

Studies investigating the association between telomere length and diabetes have been inconsistent, and there are few data available investigating the associations of telomere length with diabetes duration and control. We evaluated the relationship of leukocyte telomere length with diabetes, and the relationship of leukocyte telomere length with diabetes duration and poor glucose control among people with diabetes. We used data from the 1999-2002 National Health and Nutrition Examination Survey, a representative sample of the US civilian non-institutionalized population. In 3921 participants, leukocyte telomere length was measured and diabetes status was determined based on a previous diagnosis, hemoglobin A1c ≥ 6.5 %, or fasting glucose ≥ 126 mg/dL. The odds ratios (95 % confidence intervals) of diabetes associated with the first, second, and third quartile of leukocyte telomere length, compared to the highest quartile, was 2.09 (1.46-2.98), 1.74 (1.30-2.31), and 1.08 (0.76-1.54), respectively (p-trend < 0.01), in unadjusted models and 0.74 (0.48-1.14), 0.91 (0.61-1.34), and 0.87 (0.59-1.29), respectively (p-trend = 0.20), in multivariable adjusted models. Among participants with diabetes, unadjusted and adjusted leukocyte telomere length was not associated with diabetes duration or glucose control based on an hemoglobin A1c < 7 or < 8 % (all p > 0.05). In this study of the US general population, leukocyte telomere length was not associated with diabetes status, diabetes duration, or diabetes control.

Concerted evolution of the tandemly repeated genes encoding primate U2 small nuclear RNA (the RNU2 locus) does not prevent rapid diversification of the (CT){sub n} {center_dot} (GA){sub n} microsatellite embedded within the U2 repeat unit

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

Liao, D.; Weiner, A.M.

1995-12-10

The RNU2 locus encoding human U2 small nuclear RNA (snRNA) is organized as a nearly perfect tandem array containing 5 to 22 copies of a 5.8-kb repeat unit. Just downstream of the U2 snRNA gene in each 5.8-kb repeat unit lies a large (CT){sub n}{center_dot}(GA){sub n} dinucleotide repeat (n {approx} 70). This form of genomic organization, in which one repeat is embedded within another, provides an unusual opportunity to study the balance of forces maintaining the homogeneity of both kinds of repeats. Using a combination of field inversion gel electrophoresis and polymerase chain reaction, we have been able to studymore » the CT microsatellites within individual U2 tandem arrays. We find that the CT microsatellites within an RNU2 allele exhibit significant length polymorphism, despite the remarkable homogeneity of the surrounding U2 repeat units. Length polymorphism is due primarily to loss or gain of CT dinucleotide repeats, but other types of deletions, insertions, and substitutions are also frequent. Polymorphism is greatly reduced in regions where pure (CT){sub n} tracts are interrupted by occasional G residues, suggesting that irregularities stabilize both the length and the sequence of the dinucleotide repeat. We further show that the RNU2 loci of other catarrhine primates (gorilla, chimpanzee, ogangutan, and baboon) contain orthologous CT microsatellites; these also exhibit length polymorphism, but are highly divergent from each other. Thus, although the CT microsatellite is evolving far more rapidly than the rest of the U2 repeat unit, it has persisted through multiple speciation events spanning >35 Myr. The persistence of the CT microsatellite, despite polymorphism and rapid evolution, suggests that it might play a functional role in concerted evolution of the RNU2 loci, perhaps as an initiation site for recombination and/or gene conversion. 70 refs., 5 figs.« less

Kisspeptin mediates the photoperiodic control of reproduction in hamsters.

PubMed

Revel, Florent G; Saboureau, Michel; Masson-Pévet, Mireille; Pévet, Paul; Mikkelsen, Jens D; Simonneaux, Valérie

2006-09-05

The KiSS-1 gene encodes kisspeptin, the endogenous ligand of the G-protein-coupled receptor GPR54. Recent data indicate that the KiSS-1/GPR54 system is critical for the regulation of reproduction and is required for puberty onset. In seasonal breeders, reproduction is tightly controlled by photoperiod (i.e., day length). The Syrian hamster is a seasonal model in which reproductive activity is promoted by long summer days (LD) and inhibited by short winter days (SD). Using in situ hybridization and immunohistochemistry, we show that KiSS-1 is expressed in the arcuate nucleus of LD hamsters. Importantly, the KiSS-1 mRNA level was lower in SD animals but not in SD-refractory animals, which spontaneously reactivated their sexual activity after several months in SD. These changes of expression are not secondary to the photoperiodic variations of gonadal steroids. In contrast, melatonin appears to be necessary for these seasonal changes because pineal-gland ablation prevented the SD-induced downregulation of KiSS-1 expression. Remarkably, a chronic administration of kisspeptin-10 restored the testicular activity of SD hamsters despite persisting photoinhibitory conditions. Overall, these findings are consistent with a role of KiSS-1/GPR54 in the seasonal control of reproduction. We propose that photoperiod, via melatonin, modulates KiSS-1 signaling to drive the reproductive axis.

Growth Enhancement and Developmental Modifications of in Vitro Grown Potato (Solanum tuberosum spp. tuberosum) as Affected by a Nonfluorescent Pseudomonas sp. 1

PubMed Central

Frommel, Marcos I.; Nowak, Jerzy; Lazarovits, George

1991-01-01

A plant growth-promoting rhizobacterium, designated Ps JN and isolated from onion roots, was identified as a nonfluorescent Pseudomonas sp. The percentage of similarity of Ps JN to P. gladioli (NCPPB 1891), P. cichorii (NCPPB 943), and P. viridiflava (NCPPB 635), as determined from 135 biochemical and physiological tests was 77, 70, and 66%, respectively. Ps JN persisted through successive generations of in vitro cultured potato plantlets, both as endophytic and epiphytic populations. In vitro inoculated potato (Solanum tuberosum) nodal explants produced plantlets with significant increases in root number (24-196%), root dry weight (44-201%), haulm dry weight (14-151%), and stem length (26-28%) as compared with noninoculated control plants. Bacterization also enhanced leaf hair formation (55-110%), secondary root branching, and total plant lignin content (43%). Other root colonizing bacteria or heat-killed cells of Ps JN had no significant effect on plant growth. Detached leaves from in vitro grown control plants, when exposed to 19°C and 50% relative humidity, lost 55% of their moisture content in 2.5 hours. Moisture loss by leaves of in vitro grown, bacterized plants, as well as greenhouse-acclimated, bacterized plants, and control plants, was less than 20%. Changes in stomatal closure appear to account for this difference. ImagesFigure 2Figure 4 PMID:16668277

Fetal protection against continual exposure to bovine viral diarrhea virus following administration of a vaccine containing an inactivated bovine viral diarrhea virus fraction to cattle.

PubMed

Grooms, Daniel L; Bolin, Steven R; Coe, Paul H; Borges, Rafael J; Coutu, Christopher E

2007-12-01

To evaluate the efficacy of a commercially available killed bovine viral diarrhea virus (BVDV) vaccine to protect against fetal infection in pregnant cattle continually exposed to cattle persistently infected with the BVDV. 60 crossbred beef heifers and 4 cows persistently infected with BVDV. Beef heifers were allocated to 2 groups. One group was vaccinated twice (21-day interval between the initial and booster vaccinations) with a commercially available vaccine against BVDV, and the other group served as nonvaccinated control cattle. Estrus was induced, and the heifers were bred. Pregnancy was confirmed by transrectal palpation. Four cows persistently infected with BVDV were housed with 30 pregnant heifers (15 each from the vaccinated and nonvaccinated groups) from day 52 to 150 of gestation. Fetuses were then harvested by cesarean section and tested for evidence of BVDV infection. 1 control heifer aborted after introduction of the persistently infected cows. Bovine viral diarrhea virus was isolated from 14 of 14 fetuses obtained via cesarean section from control heifers but from only 4 of 15 fetuses obtained via cesarean section from vaccinated heifers; these proportions differed significantly. A commercially available multivalent vaccine containing an inactivated BVDV fraction significantly reduced the risk of fetal infection with BVDV in heifers continually exposed to cattle persistently infected with BVDV. However, not all vaccinated cattle were protected, which emphasizes the need for biosecurity measures and elimination of cattle persistently infected with BVDV in addition to vaccination within a herd.

Persistence border collisions in a vibrating system excited by an unbalanced motor with a relay control

NASA Astrophysics Data System (ADS)

Zhusubaliyev, Zhanybai T.; Avrutin, Viktor; Rubanov, Vasily G.; Bushuev, Dmitry A.; Titov, Dmitry V.; Yanochkina, Olga O.

2018-05-01

The paper describes a new scenario for the transition to complex dynamics in a vibrating system with an unbalanced rotor and a relay feedback control. We show that the transition from a regular dynamics without switching events in the relay element to an irregular dynamics which takes place completely in the hysteresis region occurs via a cascade of persistence border collisions.

RNA interference: a new strategy in the evolutionary arms race between human control strategies and insect pests.

PubMed

Machado, Vilmar; Rodríguez-García, María Juliana; Sánchez-García, Francisco Javier; Galan, Jose

2014-01-01

The relationship between humans and the insect pests of cultivated plants may be considered to be an indirect coevolutionary process, i.e., an arms race. Over time, humans have developed several strategies to minimize the negative impacts of insects on agricultural production. However, insects have made adaptive responses via the evolution of resistance to insecticides, and more recently against Bacillus thuriengiensis. Thus, we need to continuously invest resources in the development of new strategies for crop protection. Recent advances in genomics have demonstrated the possibility of a new weapon or strategy in this war, i.e., gene silencing, which involves blocking the expression of specific genes via mRNA inactivation. In the last decade, several studies have demonstrated the effectiveness of this strategy in the control of different species of insects. However, several technical difficulties need to be overcome to transform this potential into reality, such as the selection of target genes, the concentration of dsRNA, the nucleotide sequence of the dsRNA, the length of dsRNA, persistence in the insect body, and the life stage of the target species where gene silencing is most efficient. This study analyzes several aspects related to the use of gene silencing in pest control and it includes an overview of the inactivation process, as well as the problems that need to be resolved to transform gene silencing into an effective pest control method.

Methicillin-resistant Staphylococcus aureus nasal colonization in a level III neonatal intensive care unit: Incidence and risk factors.

PubMed

Giuffrè, Mario; Amodio, Emanuele; Bonura, Celestino; Geraci, Daniela M; Saporito, Laura; Ortolano, Rita; Corsello, Giovanni; Mammina, Caterina

2015-05-01

To describe epidemiologic features and identify risk factors for methicillin-resistant Staphylococcus aureus (MRSA) acquisition in a level III neonatal intensive care unit (NICU). A prospective, cohort study in a university-affiliated NICU with an infection control program including weekly nasal cultures of all neonates. Demographic, clinical, and microbiologic data were prospectively collected between June 2009 and June 2013. Molecular characterization of MRSA isolates was done by multilocus variable number tandem repeat fingerprinting, staphylococcal cassette chromosome mec typing, and on representative isolates by multilocus sequence typing and spa typing. Of 949 neonates, 217 (22.87%) had a culture growing MRSA, including 117 neonates testing positive at their first sampling. Of these latter infants, 96 (82.05%) were inborn and 59 (50.43%) had been transferred from the nursery. Length of stay and colonization pressure were strong independent predictors of MRSA acquisition. Among MRSA isolates, 7 sequence types were identified, with ST22-IVa, spa type t223, being the predominant strain. In an endemic area, early MRSA acquisition and high colonization pressure, likely related to an influx of colonized infants from a well-infant nursery, can support persistence of MRSA in NICUs. Surveillance, molecular tracking of strains, and reinforcement of infection control practices, involving well-infant nurseries in a comprehensive infection control program, could be helpful in containing MRSA transmission. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

The improvement of postural control in patients with mechanical ankle instability after lateral ankle ligaments reconstruction.

PubMed

Li, Hong-Yun; Zheng, Jie-Jiao; Zhang, Jian; Cai, Ye-Hua; Hua, Ying-Hui; Chen, Shi-Yi

2016-04-01

Lateral ankle sprain is the most common injury. A previous study demonstrated that patients with mechanical ankle instability suffered deficits in postural control, indicating that structural damage of the lateral ankle ligaments may produce a balance deficit. The purpose of this study was to confirm that lateral ligaments reconstruction could improve postural control in patients with mechanical ankle instability. A total of 15 patients were included in the study. Each patient had a history of an ankle sprain with persistent symptoms of ankle instability and a positive anterior drawer test and had been treated nonoperatively for at least 3 months. All patients were diagnosed with lateral ankle ligaments tear by ultrasonography and magnetic resonance imaging. They underwent arthroscopic debridement and open lateral ankle ligaments reconstruction with a modified Broström procedure. One day before and 6 months after the operation, all of the participants underwent single-limb postural sway tests. The anterior drawer test and the American Orthopedic Foot and Ankle Society scale score were used to evaluate the clinical results in these patients. At 6 months after the operation, with the patients' eyes closed, there was significantly decreased postural sway in the anteroposterior direction, the circumferential area, and the total path length on the operated ankles compared with those measurements before the operation. With eyes open, however, no difference was found in postural sway before and after the operation. Postural control was improved by reconstructing the lateral ligaments. IV.

Epitope topography controls bioactivity in supramolecular nanofibers

PubMed Central

Sur, Shantanu; Tantakitti, Faifan; Matson, John B.; Stupp, Samuel I.

2015-01-01

Incorporating bioactivity into artificial scaffolds using peptide epitopes present in the extracellular matrix (ECM) is a well-known approach. A common strategy has involved epitopes that provide cells with attachment points and external cues through interaction with integrin receptors. Although a variety of bioactive sequences have been identified so far, less is known about their optimal display in a scaffold. We report here on the use of self-assembled peptide amphiphile (PA) nanofiber matrices to investigate the impact of spatial presentation of the fibronectin derived epitope RGDS on cell response. Using one, three, or five glycine residues, RGDS epitopes were systematically spaced out from the surface of the rigid nanofibers. We found that cell morphology was strongly affected by the separation of the epitope from the nanofiber surface, with the longest distance yielding the most cell-spreading, bundling of actin filaments, and a round-to-polygonal transformation of cell shape. Cell response to this type of epitope display was also accompanied with activated integrin-mediated signaling and formation of stronger adhesions between cells and substrate. Interestingly, unlike length, changing the molecular flexibility of the linker had minimal influence on cell behavior on the substrate for reasons that remain poorly understood. The use in this study of high persistence length nanofibers rather than common flexible polymers allows us to conclude that epitope topography at the nanoscale structure of a scaffold influences its bioactive properties independent of epitope density and mechanical properties. PMID:25745558

Effects of Age and Heart Failure on Human Cardiac Stem Cell Function

PubMed Central

Cesselli, Daniela; Beltrami, Antonio P.; D'Aurizio, Federica; Marcon, Patrizia; Bergamin, Natascha; Toffoletto, Barbara; Pandolfi, Maura; Puppato, Elisa; Marino, Laura; Signore, Sergio; Livi, Ugolino; Verardo, Roberto; Piazza, Silvano; Marchionni, Luigi; Fiorini, Claudia; Schneider, Claudio; Hosoda, Toru; Rota, Marcello; Kajstura, Jan; Anversa, Piero; Beltrami, Carlo A.; Leri, Annarosa

2011-01-01

Currently, it is unknown whether defects in stem cell growth and differentiation contribute to myocardial aging and chronic heart failure (CHF), and whether a compartment of functional human cardiac stem cells (hCSCs) persists in the decompensated heart. To determine whether aging and CHF are critical determinants of the loss in growth reserve of the heart, the properties of hCSCs were evaluated in 18 control and 23 explanted hearts. Age and CHF showed a progressive decrease in functionally competent hCSCs. Chronological age was a major predictor of five biomarkers of hCSC senescence: telomeric shortening, attenuated telomerase activity, telomere dysfunction-induced foci, and p21Cip1 and p16INK4a expression. CHF had similar consequences for hCSCs, suggesting that defects in the balance between cardiomyocyte mass and the pool of nonsenescent hCSCs may condition the evolution of the decompensated myopathy. A correlation was found previously between telomere length in circulating bone marrow cells and cardiovascular diseases, but that analysis was restricted to average telomere length in a cell population, neglecting the fact that telomere attrition does not occur uniformly in all cells. The present study provides the first demonstration that dysfunctional telomeres in hCSCs are biomarkers of aging and heart failure. The biomarkers of cellular senescence identified here can be used to define the birth date of hCSCs and to sort young cells with potential therapeutic efficacy. PMID:21703415

The Role of Lexical Stress on the Use of Vocal Fry in Young Adult Female Speakers.

PubMed

Gibson, Todd A

2017-01-01

Vocal fry is a voice register often used by young adult women for sociolinguistic purposes. Some acoustic correlates of lexical stress, however, appear incompatible with the use of vocal fry. The objective of this study was to systematically examine the role of lexical stress in the use of vocal fry by young adult women. This is a semi-randomized controlled laboratory study. Fifty female undergraduate students were recorded repeating one-, two-, three-, and four-syllable nonwords that conformed to English phonotactics. Nonwords were presented in order from shorter to longer lengths, with stimuli randomized within syllable length. Perceptual analyses of recordings were augmented by acoustic analyses to identify each syllable in which vocal fry occurred. Eighty-six percent of participants produced at least one episode of vocal fry. Vocal fry was more likely to occur in unstressed than stressed position, and the likelihood increased as distance from the stressed syllable increased. There was considerable variability in the use of vocal fry. Frequent and infrequent users varied on the degree to which they used vocal fry in single-syllable nonwords. Vocal fry use persists among young adult women even in the absence of syntactic and pragmatic influences. Lexical stress appeared to dramatically reduce the use of vocal fry. Patterns of vocal fry use appeared to be different for frequent and infrequent users of this vocal register. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Association between PCBs and lower embryonic weight in black-crowned night herons in San Francisco Bay

USGS Publications Warehouse

Hoffman, D.J.; Rattner, B.A.; Bunck, C.M.; Krynitsky, A.J.; Ohlendorf, H.M.; Lowe, Roy W.

1986-01-01

Reproductive problems, including congenital malformations, reduced hatching success, and decreased survival of hatchlings, have been observed in colonial-nesting water birds at the San Francisco Bay National Wildlife Refuge (SFBNWR). Twenty-four black-crowned night heron (Nycticorax nycticorax) eggs were collected from SFBNWR in 1983. Twelve of these were collected from separate nests when late-stage embryos were pipping, and an additional egg was randomly collected from each nest for organochlorine analysis. Overt anomalies and skeletal defects were not apparent. Embryonic weights (with partially absorbed yolk sacs removed) were 15% lower (p lt 0.05) in SFBNWR embryos compared to control embryos from the Patuxent Wildlife Research Center (PWRC). Crown-rump length and femur length were shorter for SFBNWR embryos. The geometric mean polychlorinated biphenyl (PCB) concentration in SFBNWR eggs was 4.1 ppm wet weight, with a range of 0.8-52.0 ppm. A negative correlation (r = - 0.61; p lt 0.05) existed between embryonic weight and log-transformed PCB residues in whole eggs collected from the same nest at SFBNWR, suggesting a possible impact of PCBs on embryonic growth. A correlation with embryonic weight did not occur for DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) residues. Liver microsomal aryl hydrocarbon hydroxylase activity was neither significantly elevated nor correlated with PCB, DDE, or PCB plus DDE log-transformed residues. It is unknown whether the apparent association between PCBs and lower weight is persistent through hatching.

Atopy, but not obesity is associated with asthma severity among children with persistent asthma.

PubMed

Lu, Kim D; Phipatanakul, Wanda; Perzanowski, Matthew S; Balcer-Whaley, Susan; Matsui, Elizabeth C

2016-12-01

Obesity is associated with an increased risk of asthma in children. Atopic sensitization is a major risk factor for asthma including severe asthma in children. It is unclear if obesity is associated with worse asthma control or severity in children and how its effects compare to atopy. We sought to examine relationships of weight status and atopy to asthma control and severity among a population of predominantly low income, minority children and adolescents with persistent asthma. A cross-sectional analysis of 832 children and adolescents, age range 5-17 years, with persistent asthma was performed. Clinical assessments included asthma questionnaires of symptoms, asthma severity score, health care utilization and medication treatment step, lung function testing, and skin prick testing as well as measures of adiposity. Data were collected between December 2010 and August 2014 from Johns Hopkins Hospital in Baltimore, MD and Children's Hospital of Boston, MA. Obesity was not associated with worse asthma control or severity in this group of predominantly low income, minority children and adolescents with persistent asthma. However, a greater degree of atopy was associated with lower lung function, higher asthma severity score, and higher medication treatment step. Atopy may be a more important risk factor for asthma severity than obesity among low-income minority children and adolescents with persistent asthma living in Northeastern cities in the United States.

The benefits of sustained leisure-time physical activity on job strain.

PubMed

Yang, X; Telama, R; Hirvensalo, M; Hintsanen, M; Hintsa, T; Pulkki-Råback, L; Viikari, J S A

2010-08-01

The long-term effects of leisure-time physical activity (LTPA) on job strain have not been assessed in a large prospective population-based cohort study. To examine the relationship between the LTPA and the prevalence of job strain. The participants were 861 full-time employees (406 men and 455 women), aged 24-39 years in 2001, from the ongoing Cardiovascular Risk in Young Finns Study. LTPA was assessed using a self-report questionnaire in 1992 and in 2001. The participants were grouped into four categories according to tertiles of LTPA index at two time points: persistently active, increasingly active, decreasingly active and persistently inactive. Job strain was measured in 2001 by indicators of job demands and job control. Baseline LTPA was inversely associated with job strain (P < 0.001) and job demands (P < 0.05) and directly associated with job control (P < 0.05) in both sexes in a model adjusted for the change in 9-year LTPA, age, educational level, occupational status and smoking. Compared with persistently active participants, persistently inactive participants had a 4.0-fold higher job strain after adjustment for the confounders. Similarly, persistently inactive participants had a 2.7-fold higher job demands and a 1.8-fold lower job control. Decreasing physical activity was independently associated with high job strain (P < 0.01) and with low job control (P < 0.01). Participation in regular LTPA during leisure may help young adults to cope with job strain. A long-term benefit of LTPA may play a role in the development of mental well-being.

Prefrontal and parietal correlates of cognitive control related to the adult outcome of attention-deficit/hyperactivity disorder diagnosed in childhood.

PubMed

Schulz, Kurt P; Li, Xiaobo; Clerkin, Suzanne M; Fan, Jin; Berwid, Olga G; Newcorn, Jeffrey H; Halperin, Jeffrey M

2017-05-01

The protracted and highly variable development of prefrontal cortex regions that support cognitive control has been purported to shape the adult outcome of attention-deficit/hyperactivity disorder (ADHD). This neurodevelopmental model was tested in a prospectively followed sample of 27 adult probands who were diagnosed with ADHD in childhood and 28 carefully matched comparison subjects aged 21-28 years. Probands were classified with persistent ADHD or remitted ADHD. Behavioral and neural responses to the Stimulus and Response Conflict Task (SRCT) performed during functional magnetic resonance imaging (fMRI) were compared in probands and comparison subjects and in probands with persistent and remitted ADHD. Response speed and accuracy for stimulus, response, and combined conflicts did not differ across groups. Orbitofrontal, inferior frontal and parietal activation was lower in probands than comparison subjects, but only for combined conflicts, when demand for cognitive control was highest. Reduced activation for combined conflicts in probands was almost wholly attributable to the persistence of ADHD; orbitofrontal, inferior frontal, anterior cingulate and parietal activation was lower in probands with persistent ADHD than both probands with remitted ADHD and comparison subjects, but did not differ between probands with remitted ADHD and comparison subjects. These data provide the first evidence that prefrontal and parietal activation during cognitive control parallels the adult outcome of ADHD diagnosed in childhood, with persistence of symptoms linked to reduced activation and symptom recovery associated with activation indistinguishable from adults with no history of ADHD. Copyright © 2017 Elsevier Ltd. All rights reserved.

Seek and destroy process: Listeria monocytogenes process controls in the ready-to-eat meat and poultry industry.

PubMed

Malley, Thomas J V; Butts, John; Wiedmann, Martin

2015-02-01

The majority of human listeriosis cases appear to be caused by consumption of ready-to-eat (RTE) foods contaminated at the time of consumption with high levels of Listeria monocytogenes. Although strategies to prevent growth of L. monocytogenes in RTE products are critical for reducing the incidence of human listeriosis, control of postprocessing environmental contamination of RTE meat and poultry products is an essential component of a comprehensive L. monocytogenes intervention and control program. Complete elimination of postprocessing L. monocytogenes contamination is challenging because this pathogen is common in various environments outside processing plants and can persist in food processing environments for years. Persistent L. monocytogenes strains in processing plants have been identified as the most common postprocessing contaminants of RTE foods and the cause of multiple listeriosis outbreaks. Identification and elimination of L. monocytogenes strains persisting in processing plants is thus critical for (i) compliance with zero-tolerance regulations for L. monocytogenes in U.S. RTE meat and poultry products and (ii) reduction of the incidence of human listeriosis. The seek-and-destroy process is a systematic approach to finding sites of persistent strains (niches) in food processing plants, with the goal of either eradicating or mitigating effects of these strains. This process has been used effectively to address persistent L. monocytogenes contamination in food processing plants, as supported by peer-reviewed evidence detailed here. Thus, a regulatory environment that encourages aggressive environmental Listeria testing is required to facilitate continued use of this science-based strategy for controlling L. monocytogenes in RTE foods.

Piezo activated mode tracking system for widely tunable mode-hop-free external cavity mid-IR semiconductor lasers

NASA Technical Reports Server (NTRS)

Tittel, Frank K. (Inventor); Curl, Robert F. (Inventor); Wysocki, Gerard (Inventor)

2010-01-01

A widely tunable, mode-hop-free semiconductor laser operating in the mid-IR comprises a QCL laser chip having an effective QCL cavity length, a diffraction grating defining a grating angle and an external cavity length with respect to said chip, and means for controlling the QCL cavity length, the external cavity length, and the grating angle. The laser of claim 1 wherein said chip may be tuned over a range of frequencies even in the absence of an anti-reflective coating. The diffraction grating is controllably pivotable and translatable relative to said chip and the effective QCL cavity length can be adjusted by varying the injection current to the chip. The laser can be used for high resolution spectroscopic applications and multi species trace-gas detection. Mode-hopping is avoided by controlling the effective QCL cavity length, the external cavity length, and the grating angle so as to replicate a virtual pivot point.

Long-term pain prevalence and health-related quality of life outcomes for patients enrolled in a ketamine versus morphine for prehospital traumatic pain randomised controlled trial.

PubMed

Jennings, Paul A; Cameron, Peter; Bernard, Stephen; Walker, Tony; Jolley, Damien; Fitzgerald, Mark; Masci, Kevin

2014-10-01

Improved early pain control may affect the longer-term prevalence of persistent pain. In a previous randomised, controlled trial, we found that the administration of ketamine on hospital arrival decreased pain scores to a greater extent than morphine alone in patients with prehospital traumatic pain. In this follow-up study, we sought to determine the prevalence of persistent pain and whether there were differences in patients who received ketamine or morphine. This study was a long-term follow-up study of the prehospital, prospective, randomised, controlled, open-label study comparing ketamine with morphine in patients with trauma and a verbal pain score of >5 after 5 mg intravenous morphine. Patients were followed-up by telephone 6-12 months after enrollment, and a questionnaire including the SF-36 (V.2) health-related quality of life survey and the Verbal Numerical Rating Scale for pain was administered. A total of 97/135 (72%) patients were able to be followed-up 6-12 months after enrollment between July 2008 and July 2010. Overall, 44/97 (45%) participants reported persistent pain related to their injury, with 3/97 (3%) reporting persistent severe pain. The prevalence of persistent pain was the same between study groups (22/50 (44%) for the ketamine group vs 22/47 (46%) for the morphine group). There was no difference in the SF-36 scores between study arms. There is a high incidence of persistent pain after traumatic injury, even in patients with relatively minor severity of injury. Although decreased pain scores at hospital arrival are achieved with ketamine compared with morphine, this difference does not affect the prevalence of persistent pain or health-related quality of life 6 months after injury. Further larger studies are required to confirm this finding. Australian and New Zealand Clinical Trials Registry (ACTRN12607000441415). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Postnatal persistence of fetal cardiovascular remodeling associated with assisted reproductive technologies: a cohort study.

PubMed

Valenzuela-Alcaraz, Brenda; Serafini, Audrey; Sepulveda-Martínez, Alvaro; Casals, Gemma; Rodríguez-López, Merida; Garcia-Otero, Laura; Cruz-Lemini, Monica; Bijnens, Bart; Sitges, Marta; Balasch, Juan; Gratacos, Eduard; Crispi, Fatima

2018-04-19

to assess the postnatal persistence of fetal cardiovascular remodeling associated to assisted reproductive technologies (ART), in children at 3 years of age. A cohort study of children conceived by ART. Maternal-Fetal Medicine Unit, Hospital Clinic Barcelona, Spain. 80 singleton pregnancies conceived by ART and 80 spontaneously conceived (controls) followed from fetal life up to childhood. Cardiovascular evaluation was performed at 3 years of corrected age, including echocardiography, carotid intima-media (cIMT) by ultrasound and blood pressure. Postnatal persistence of cardiovascular changes in children conceived by ART. As compared to controls, children conceived by ART showed larger atria (right atrial area: control 4.9 cm 2 (0.9) vs. ART 5.5 cm 2 (0.9), p<0.001), more globular ventricles (right ventricular sphericity index: control mean 1.8 (SD 0.5) vs. ART 1.6 (0.2), p<0.001), and signs of systolic (tricuspid annular plane systolic excursion: control 18 mm (2) vs. ART 16 mm (3), p<0.001) and diastolic dysfunction (isovolumic relaxation time: control 68 ms (12) vs. ART 79 ms (12), p<0.001). ART children also presented increased systolic blood pressure (control 90 mmHg (6) vs. ART 94 mmHg (5), p<0.003) and cIMT (control 0.52 μm (0.14) vs. ART 0.60 μm (0.16), p<0.001) as compared to those spontaneously conceived. Cardiovascular changes previously reported in ART fetuses persist postnatally at 3 years of age. These results underscore the importance of future studies for assessing the long-term cardiovascular health associated to ART. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Relative persistence and dispersal of age-0 and age-1 largemouth bass stocked into two Ohio River embayments

USGS Publications Warehouse

Hartman, K.J.; Janney, E.C.

2006-01-01

In October of 1998 the West Virginia Division of Natural Resources stocked age-0 [mean total length (MTL) = 178 mm] and age-1 (MTL = 273 mm) hatchery-reared largemouth bass into two embayments of the Ohio River. Stocked fish were fitted with both an anchor tag and a visible implant elastomer mark. A multifaceted sampling approach was undertaken to (1) evaluate the persistence of stocked largemouth bass, (2) estimate fidelity of stocked largemouth bass to release sites, and (3) compare return rates of the two age classes. Although stocked largemouth bass comprised the majority (81%) of all bass captured in electrofishing surveys of the stocked embayments during fall 1998, catches declined rapidly during winter 1998, and by spring and summer 1999 stocked largemouth bass were virtually absent from electrofishing surveys. Creel surveys indicated no catch of stocked largemouth bass in the release sites after winter 1998. Electrofishing surveys, creel surveys, and angler call-ins all suggested stocked fish did not persist and either moved out of the stocked embayments or died. The results suggest that stocking advanced-size largemouth bass into these embayments only provided a limited and short-term enhancement of the fishery in those areas.

On the nature of persistence in dendrochronologic records with implications for hydrology

USGS Publications Warehouse

Landwehr, J.M.; Matalas, N.C.

1986-01-01

Hydrologic processes are generally held to be persistent and not secularly independent. Impetus for this view was given by Hurst in his work which dealt with properties of the rescaled range of many types of long geophysical records, in particular dendrochronologic records, in addition to hydrologic records. Mandelbrot introduced an infinite memory stationary process, the fractional Gaussian noise process (F), as an explanation for Hurst's observations. This is in contrast to other explanations which have been predicated on the implicit non-stationarity of the process underlying the construction of the records. In this work, we introduce a stationary finite memory process which arises naturally from a physical concept and show that it can accommodate the persistence structures observed for dendrochronological records more successfully than an F or any other of a family of related processes examined herein. Further, some question arises as to the empirical plausibility of an F process. Dendrochronologic records are used because they are widely held to be surrogates for records of average hydrologic phenomena and the length of these records allows one to explore questions of stochastic process structure which cannot be explored with great validity in the case of generally much shorter hydrologic records. ?? 1986.

Early postoperative and late metabolic morbidity after pancreatic resections: An old and new challenge for surgeons - A review.

PubMed

Beger, Hans G; Mayer, Benjamin

2018-02-16

The metrics for measuring early postoperative morbidity after resection of pancreatic neoplastic tumors are overall morbidity, severe surgery-related morbidity, frequency of reoperation and reintervention, in-hospital, 30-day and 90-day mortality and length of hospital stay. Thirty-day readmission after discharge is additionally an indispensable criterion to assess quality of surgery. The metrics for surgery-associated long-term results after pancreatic resections are survival times, new onset of diabetes (DM), impaired glucose tolerance, exocrine pancreatic insufficiency, body mass index and GI motility dysfunctions. Following pancreaticoduodenectomy (PD) performed on pancreatic normo-glycemic patients for malignant and benign tumors, 4-30% develop postoperative new onset of diabetes. Long-term persistence of diabetes mellitus is observed after surgery for benign tumors in 14% and in 15.5% of patients after cancer resection. Pancreatic exocrine insufficiency after PD is observed in the early postoperative period in 23-80% of patients. Persistence of exocrine dysfunctions exists in 25% and 49% of patients. Following left-sided pancreatic resection, new onset DM is observed in 14% of cases; an exocrine insufficiency persisting in the long-term outcome is observed in 16-28% of patients. Copyright © 2018 Elsevier Inc. All rights reserved.

Progress in the understanding and utilization of biologic response modifiers in the treatment of uveitis.

PubMed

Maleki, Arash; Meese, Halea; Sahawneh, Haitham; Foster, C Stephen

2016-07-01

Uveitis is the third most common cause of blindness in developed countries. Considering the systemic and local complications of long-term corticosteroid therapy and the intolerance due to side effects and ineffectiveness of conventional chemotherapy, use of biologic response modifiers is a reasonable alternative in the treatment of non-infectious uveitis and persistent uveitic macular edema. The majority of the evidence presented here comes from open uncontrolled analyses. Based on these studies, tumor necrosis factor alpha inhibitors, especially infliximab and adalimumab, have been shown to be effective in the treatment of non-infectious uveitis in numerous studies. More research is necessary, particularly multi-center randomized clinical trials, to address the choice of biologic response modifier agent and the length of treatment as we employ biologic response modifiers in different types of uveitis and persistent uveitic macular edema.

Long-term persistence of solar activity

NASA Technical Reports Server (NTRS)

Ruzmaikin, Alexander; Feynman, Joan; Robinson, Paul

1994-01-01

We examine the question of whether or not the non-periodic variations in solar activity are caused by a white-noise, random process. The Hurst exponent, which characterizes the persistence of a time series, is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD. We find a constant Hurst exponent, suggesting that solar activity in the frequency range from 100 to 3000 years includes an important continuum component in addition to the well-known periodic variations. The value we calculate, H approximately 0.8, is significantly larger than the value of 0.5 that would correspond to variations produced by a white-noise process. This value is in good agreement with the results for the monthly sunspot data reported elsewhere, indicating that the physics that produces the continuum is a correlated random process and that it is the same type of process over a wide range of time interval lengths.

Quantification of sweat gland volume and innervation in neuropathy: Correlation with thermoregulatory sweat testing.

PubMed

Loavenbruck, Adam; Wendelschaefer-Crabbe, Gwen; Sandroni, Paola; Kennedy, William R

2014-10-01

No study has correlated thermoregulatory sweat testing (TST) with histopathologic study of sweat glands (SGs) and SG nerve fibers (SGNFs). We studied 10 neuropathy patients in whom anhidrosis was found by TST and 10 matched controls. Skin biopsies were taken from both anhidrotic and sweating skin and immunohistochemical staining was done for nerves and basement membrane. For each biopsy, total tissue volume, total SG volume, and total SGNF length were measured. SGNF length per biopsy volume, SG volume per biopsy volume (SG%), and SGNF length per SG volume were calculated. SGNF length per biopsy volume was reduced in anhidrotic site biopsies of patients compared with controls. SG% was decreased and SGNF length per SG volume increased in patients compared with controls. The results suggest a concomitant loss of SG volume and SGNF length in neuropathy, with greater loss of SGNFs in anhidrotic skin, possibly exceeding collateral reinnervation. Copyright © 2014 Wiley Periodicals, Inc.

Telomere Length from Blood Cells and Breast Cancer Risk: Investigations in two case-control studies

PubMed Central

Zheng, Yun-Ling; Ambrosone, Christine; Byrne, Celia; Davis, Warren; Nesline, Mary; McCann, Susan E.

2013-01-01

Purpose Telomere dysfunction, which leads to genomic instability, is hypothesized to play a causal role in the development of breast cancer. However, the few epidemiologic studies that assessed the relationship between telomere length in blood cells and breast cancer risk have been inconsistent. We conducted two case-control studies to further understand the role of telomere length and breast cancer risk. Methods Overall telomere lengths were measured by telomere quantitative fluorescent in situ hybridization (TQ-FISH) and telomere quantitative real-time PCR (TQ-PCR). The associations between telomere length from blood leucocytes and risk of breast cancer were examine in two breast cancer case-control studies that were conducted at Roswell Park Cancer Institute (RPCI) and Lombardi Comprehensive Cancer Center (LCCC). Results Using the 50th percentile value in controls as a cut point, women who had shorter telomere length were not at significantly increased risk of breast cancer compared with women who had longer telomere length in the RPCI study (odds ratio [OR] = 1.34, 95% confidence interval [CI] = 0.84 to 2.12), in the LCCC study (OR = 1.18, 95% CI = 0.73 to 1.91), or in the combined RPCI and LCCC studies (OR = 1.23, 95% CI = 0.89 to 1.71). There was no significant dose-response relationship across quartiles of telomere length and no significant difference when comparing women in the lowest to highest quartile of telomere length. Conclusions Overall telomere length from blood leucocytes was not significantly associated with the risk of breast cancer. PMID:19543829

Does neighborhood size really cause the word length effect?

PubMed

Guitard, Dominic; Saint-Aubin, Jean; Tehan, Gerald; Tolan, Anne

2018-02-01

In short-term serial recall, it is well-known that short words are remembered better than long words. This word length effect has been the cornerstone of the working memory model and a benchmark effect that all models of immediate memory should account for. Currently, there is no consensus as to what determines the word length effect. Jalbert and colleagues (Jalbert, Neath, Bireta, & Surprenant, 2011a; Jalbert, Neath, & Surprenant, 2011b) suggested that neighborhood size is one causal factor. In six experiments we systematically examined their suggestion. In Experiment 1, with an immediate serial recall task, multiple word lengths, and a large pool of words controlled for neighborhood size, the typical word length effect was present. In Experiments 2 and 3, with an order reconstruction task and words with either many or few neighbors, we observed the typical word length effect. In Experiment 4 we tested the hypothesis that the previous abolition of the word length effect when neighborhood size was controlled was due to a confounded factor: frequency of orthographic structure. As predicted, we reversed the word length effect when using short words with less frequent orthographic structures than the long words, as was done in both of Jalbert et al.'s studies. In Experiments 5 and 6, we again observed the typical word length effect, even if we controlled for neighborhood size and frequency of orthographic structure. Overall, the results were not consistent with the predictions of Jalbert et al. and clearly showed a large and reliable word length effect after controlling for neighborhood size.

Understanding desisting and persisting forms of delinquency: the unique contributions of disruptive behavior disorders and interpersonal callousness

PubMed Central

Byrd, Amy L.; Loeber, Rolf; Pardini, Dustin A.

2013-01-01

Background While associations between conduct disorder (CD), oppositional defiant disorder (ODD), attention deficit hyperactivity disorder (ADHD), and interpersonal callousness (IC) symptoms and delinquency onset are well established, less is known about whether these characteristics differentiate desisting and persisting delinquency. The current study examined whether childhood and adolescent CD, ODD, ADHD, and IC symptoms uniquely distinguished boys who exhibited persisting versus desisting delinquency from adolescence into adulthood. Methods Participants were 503 boys (57% African American) repeatedly assessed from ages 7 to 25. Associations between childhood and adolescent CD, ODD, ADHD, and IC symptoms and desisting and persisting delinquency were examined independently and after controlling for their co-occurrence and multiple covariates. Results Conduct disorder and IC symptoms in childhood and adolescence were higher among boys whose delinquency persisted into adulthood relative to those boys whose delinquency desisted across time. After controlling for the overlap between symptoms of ADHD, ODD, CD and IC, only adolescent CD and IC symptoms emerged as unique predictors of the differentiation between persisters and desisters. Moreover, adolescent CD and IC symptoms continued to contribute unique variance even after childhood levels of these characteristics were accounted for. Conclusions Boys with elevated levels of CD and IC symptoms in childhood and adolescence are at risk for exhibiting a pattern of delinquency that persists from adolescence into adulthood. Intervention efforts designed to prevent chronic delinquency should target youth with co-occurring CD and IC symptoms in childhood and adolescence. PMID:22176342

Statistical definition of relapse: case of family drug court.

PubMed

Alemi, Farrokh; Haack, Mary; Nemes, Susanna

2004-06-01

At any point in time, a patient's return to drug use can be seen either as a temporary event or as a return to persistent use. There is no formal standard for distinguishing persistent drug use from an occasional relapse. This lack of standardization persists although the consequences of either interpretation can be life altering. In a drug court or regulatory situation, for example, misinterpreting relapse as return to drug use could lead to incarceration, loss of child custody, or loss of employment. A clinician who mistakes a client's relapse for persistent drug use may fail to adjust treatment intensity to client's needs. An empirical and standardized method for distinguishing relapse from persistent drug use is needed. This paper provides a tool for clinicians and judges to distinguish relapse from persistent use based on statistical analyses of patterns of client's drug use. To accomplish this, a control chart is created for time-in-between relapses. This paper shows how a statistical limit can be calculated by examining either the client's history or other clients in the same program. If client's time-in-between relapse exceeds the statistical limit, then the client has returned to persistent use. Otherwise, the drug use is temporary. To illustrate the method, it is applied to data from three family drug courts. The approach allows the estimation of control limits based on the client's as well as the court's historical patterns. The approach also allows comparison of courts based on recovery rates.

Rif1 acts through Protein Phosphatase 1 but independent of replication timing to suppress telomere extension in budding yeast.

PubMed

Kedziora, Sylwia; Gali, Vamsi K; Wilson, Rosemary H C; Clark, Kate R M; Nieduszynski, Conrad A; Hiraga, Shin-Ichiro; Donaldson, Anne D

2018-05-04

The Rif1 protein negatively regulates telomeric TG repeat length in the budding yeast Saccharomyces cerevisiae, but how it prevents telomere over-extension is unknown. Rif1 was recently shown to control DNA replication by acting as a Protein Phosphatase 1 (PP1)-targeting subunit. Therefore, we investigated whether Rif1 controls telomere length by targeting PP1 activity. We find that a Rif1 mutant defective for PP1 interaction causes a long-telomere phenotype, similar to that of rif1Δ cells. Tethering PP1 at a specific telomere partially substitutes for Rif1 in limiting TG repeat length, confirming the importance of PP1 in telomere length control. Ablating Rif1-PP1 interaction is known to cause precocious activation of telomere-proximal replication origins and aberrantly early telomere replication. However, we find that Rif1 still limits telomere length even if late replication is forced through deletion of nearby replication origins, indicating that Rif1 can control telomere length independent of replication timing. Moreover we find that, even at a de novo telomere created after DNA synthesis during a mitotic block, Rif1-PP1 interaction is required to suppress telomere lengthening and prevent inappropriate recruitment of Tel1 kinase. Overall, our results show that Rif1 controls telomere length by recruiting PP1 to directly suppress telomerase-mediated TG repeat lengthening.

An Introduction to the properties of Superconductors

NASA Astrophysics Data System (ADS)

Letarte, Alec

2001-03-01

A brief introductory presentation of the various properties of superconductors. The discussion will be focussed mainly on the newer ceramic superconductors, but the classic metal ones will also be touched upon. Some of the properties to be considered are: Optical properties, transport properties, persistent currents, coherence length, flux magnetisation, and the ``anti-gravity effect" produced be superconductors Another subject to be looked at will be the recent technological uses and developments of superconductors. For example, they have developed thin superconductors which they are making into a superconducting cable.

Casting Metal Nanowires Within Discrete Self-Assembled Peptide Nanotubes

NASA Astrophysics Data System (ADS)

Reches, Meital; Gazit, Ehud

2003-04-01

Tubular nanostructures are suggested to have a wide range of applications in nanotechnology. We report our observation of the self-assembly of a very short peptide, the Alzheimer's β-amyloid diphenylalanine structural motif, into discrete and stiff nanotubes. Reduction of ionic silver within the nanotubes, followed by enzymatic degradation of the peptide backbone, resulted in the production of discrete nanowires with a long persistence length. The same dipeptide building block, made of D-phenylalanine, resulted in the production of enzymatically stable nanotubes.

Observations of Hall Reconnection Physics Far Downstream of the X Line.

PubMed

Mistry, R; Eastwood, J P; Haggerty, C C; Shay, M A; Phan, T D; Hietala, H; Cassak, P A

2016-10-28

Observations made using the Wind spacecraft of Hall magnetic fields in solar wind reconnection exhausts are presented. These observations are consistent with the generation of Hall fields by a narrow ion inertial scale current layer near the separatrix, which is confirmed with an appropriately scaled particle-in-cell simulation that shows excellent agreement with observations. The Hall fields are observed thousands of ion inertial lengths downstream from the reconnection X line, indicating that narrow regions of kinetic dynamics can persist extremely far downstream.

Extreme ionization of Xe clusters driven by ultraintense laser fields

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

Heidenreich, Andreas; Last, Isidore; Jortner, Joshua

We applied theoretical models and molecular dynamics simulations to explore extreme multielectron ionization in Xe{sub n} clusters (n=2-2171, initial cluster radius R{sub 0}=2.16-31.0 A ring ) driven by ultraintense infrared Gaussian laser fields (peak intensity I{sub M}=10{sup 15}-10{sup 20} W cm{sup -2}, temporal pulse length {tau}=10-100 fs, and frequency {nu}=0.35 fs{sup -1}). Cluster compound ionization was described by three processes of inner ionization, nanoplasma formation, and outer ionization. Inner ionization gives rise to high ionization levels (with the formation of (Xe{sup q+}){sub n} with q=2-36), which are amenable to experimental observation. The cluster size and laser intensity dependence of themore » inner ionization levels are induced by a superposition of barrier suppression ionization (BSI) and electron impact ionization (EII). The BSI was induced by a composite field involving the laser field and an inner field of the ions and electrons, which manifests ignition enhancement and screening retardation effects. EII was treated using experimental cross sections, with a proper account of sequential impact ionization. At the highest intensities (I{sub M}=10{sup 18}-10{sup 20} W cm{sup -2}) inner ionization is dominated by BSI. At lower intensities (I{sub M}=10{sup 15}-10{sup 16} W cm{sup -2}), where the nanoplasma is persistent, the EII contribution to the inner ionization yield is substantial. It increases with increasing the cluster size, exerts a marked effect on the increase of the (Xe{sup q+}){sub n} ionization level, is most pronounced in the cluster center, and manifests a marked increase with increasing the pulse length (i.e., becoming the dominant ionization channel (56%) for Xe{sub 2171} at {tau}=100 fs). The EII yield and the ionization level enhancement decrease with increasing the laser intensity. The pulse length dependence of the EII yield at I{sub M}=10{sup 15}-10{sup 16} W cm{sup -2} establishes an ultraintense laser pulse length control mechanism of extreme ionization products.« less

Spatial and temporal trends of persistent organic pollutants and mercury in beluga whales (Delphinapterus leucas) from Alaska.

PubMed

Hoguet, Jennifer; Keller, Jennifer M; Reiner, Jessica L; Kucklick, John R; Bryan, Colleen E; Moors, Amanda J; Pugh, Rebecca S; Becker, Paul R

2013-04-01

Remote locations, such as the Arctic, are often sinks for persistent contaminants which can ultimately bioaccumulate in local wildlife. Assessing temporal contaminant trends in the Arctic is important in understanding whether restrictions on legacy persistent organic pollutants (POPs) have led to concentration declines. Beluga whale (Delphinapterus leucas) tissue samples were collected from two subpopulations (Cook Inlet, Alaska and the eastern Chukchi Sea) between 1989 and 2006. Several POPs (polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethane and related compounds (DDTs), chlordanes, hexachlorocyclohexanes (HCHs), chlorobenzenes, mirex, polybrominated diphenyl ethers (PBDEs) and semi-quantitatively hexabromocyclododecanes (HBCDs)) were measured in 70 blubber samples, and total mercury (Hg) was measured in 67 liver samples from a similar set of individuals. Legacy POPs (PCBs, chlordanes, DDTs, and HCHs) were the predominant organic compound classes in both subpopulations, with median concentrations of 2360ng/g lipid for Σ80PCBs and 1890 ng/g lipid for Σ6DDTs. Backward stepwise multiple regressions showed that at least one of the four independent variables (subpopulation, sampling year, sex, and animal length) influenced the POP and Hg concentrations. ΣPCBs, ΣDDTs, Σchlordanes, Σchlorobenzenes, mirex, and Hg were significantly higher in belugas from the eastern Chukchi Sea than from the Cook Inlet (p≤0.0001). In contrast, Σ8PBDE and α-HBCD concentrations were significantly lower in belugas from the eastern Chukchi Sea than from the Cook Inlet (p<0.0001). Significant temporal increases in concentrations of Σ8PBDE and α-HBCD were observed for both subpopulations (p≤0.0003), and temporal declines were seen for ΣHCHs and Σchlorobenzenes in eastern Chukchi Sea belugas only (p≤0.0107). All other POP and Hg concentrations were stable, indicating either a lagging response of the Arctic to source reductions or the maintenance of concentrations by unregulated sources. Sex and length also significantly influenced some concentrations, and these findings are discussed. Published by Elsevier B.V.

Impact of alemtuzumab on HIV persistence in an HIV-infected individual on antiretroviral therapy with Sezary syndrome.

PubMed

Rasmussen, Thomas A; McMahon, James; Chang, J Judy; Symons, Jori; Roche, Michael; Dantanarayana, Ashanti; Okoye, Afam; Hiener, Bonnie; Palmer, Sarah; Lee, Wen Shi; Kent, Stephen J; Van Der Weyden, Carrie; Prince, H Miles; Cameron, Paul U; Lewin, Sharon R

2017-08-24

To study the effects of alemtuzumab on HIV persistence in an HIV-infected individual on antiretroviral therapy (ART) with Sezary syndrome, a rare malignancy of CD4 T cells. Case report. Blood was collected 30 and 18 months prior to presentation with Sezary syndrome, at the time of presentation and during alemtuzumab. T-cell subsets in malignant (CD7-CD26-TCR-VBeta2+) and nonmalignant cells were quantified by flow cytometry. HIV-DNA in total CD4 T cells, in sorted malignant and nonmalignant CD4 T cells, was quantified by PCR and clonal expansion of HIV-DNA assessed by full-length next-generation sequencing. HIV-hepatitis B virus coinfection was diagnosed and antiretroviral therapy initiated 4 years prior to presentation with Sezary syndrome and primary cutaneous anaplastic large cell lymphoma. The patient received alemtuzumab 10 mg three times per week for 4 weeks but died 6 weeks post alemtuzumab. HIV-DNA was detected in nonmalignant but not in malignant CD4 T cells, consistent with expansion of a noninfected CD4 T-cell clone. Full-length HIV-DNA sequencing demonstrated multiple defective viruses but no identical or expanded sequences. Alemtuzumab extensively depleted T cells, including more than 1 log reduction in total T cells and more than 3 log reduction in CD4 T cells. Finally, alemtuzumab decreased HIV-DNA in CD4 T cells by 57% but HIV-DNA remained detectable at low levels even after depletion of nearly all CD4 T cells. Alemtuzumab extensively depleted multiple T-cell subsets and decreased the frequency of but did not eliminate HIV-infected CD4 T cells. Studying the effects on HIV persistence following immune recovery in HIV-infected individuals who require alemtuzumab for malignancy or in animal studies may provide further insights into novel cure strategies.

Trochanteric bursitis after total hip arthroplasty: incidence and evaluation of response to treatment.

PubMed

Farmer, Kevin W; Jones, Lynne C; Brownson, Kirstyn E; Khanuja, Harpal S; Hungerford, Marc W

2010-02-01

We examined the efficacy of corticosteroid injection as treatment for postarthroplasty trochanteric bursitis and the risk factors for failure of nonoperative treatment. There were 32 (4.6%) cases of postsurgical trochanteric bursitis in 689 primary total hip arthroplasties. Of the 25 hips with follow-up, 11 (45%) required multiple injections. Symptoms resolved in 20 (80%) but persisted in 5. We found no statistically significant differences between patients who did and did not develop trochanteric bursitis, or between those who did and did not respond to treatment. There was a trend toward younger age and greater limb-length discrepancy in nonresponders. In conclusion, (1) corticosteroid injection(s) for postoperative trochanteric bursitis is effective; and (2) nonoperative management may be more likely to fail in young patients and those with leg-length discrepancy. 2010 Elsevier Inc. All rights reserved.

Buckling of stiff polymers: Influence of thermal fluctuations

NASA Astrophysics Data System (ADS)

Emanuel, Marc; Mohrbach, Hervé; Sayar, Mehmet; Schiessel, Helmut; Kulić, Igor M.

2007-12-01

The buckling of biopolymers is a frequently studied phenomenon The influence of thermal fluctuations on the buckling transition is, however, often ignored and not completely understood. A quantitative theory of the buckling of a wormlike chain based on a semiclassical approximation of the partition function is presented. The contribution of thermal fluctuations to the force-extension relation that allows one to go beyond the classical Euler buckling is derived in the linear and nonlinear regimes as well. It is shown that the thermal fluctuations in the nonlinear buckling regime increase the end-to-end distance of the semiflexible rod if it is confined to two dimensions as opposed to the three-dimensional case. The transition to a buckled state softens at finite temperature. We derive the scaling behavior of the transition shift with increasing ratio of contour length versus persistence length.

Basic visual perceptual processes in children with typical development and cerebral palsy: The processing of surface, length, orientation, and position.

PubMed

Schmetz, Emilie; Magis, David; Detraux, Jean-Jacques; Barisnikov, Koviljka; Rousselle, Laurence

2018-03-02

The present study aims to assess how the processing of basic visual perceptual (VP) components (length, surface, orientation, and position) develops in typically developing (TD) children (n = 215, 4-14 years old) and adults (n = 20, 20-25 years old), and in children with cerebral palsy (CP) (n = 86, 5-14 years old) using the first four subtests of the Battery for the Evaluation of Visual Perceptual and Spatial processing in children. Experiment 1 showed that these four basic VP processes follow distinct developmental trajectories in typical development. Experiment 2 revealed that children with CP present global and persistent deficits for the processing of basic VP components when compared with TD children matched on chronological age and nonverbal reasoning abilities.

Feedback control of persistent-current oscillation based on the atomic-clock technique

NASA Astrophysics Data System (ADS)

Yu, Deshui; Dumke, Rainer

2018-05-01

We propose a scheme of stabilizing the persistent-current Rabi oscillation based on the flux qubit-resonator-atom hybrid structure. The low-Q L C resonator weakly interacts with the flux qubit and maps the persistent-current Rabi oscillation of the flux qubit onto the intraresonator electric field. This oscillating electric field is further coupled to a Rydberg-Rydberg transition of the 87Rb atoms. The Rabi-frequency fluctuation of the flux qubit is deduced from measuring the atomic population via the fluorescence detection and stabilized by feedback controlling the external flux bias. Our numerical simulation indicates that the feedback-control method can efficiently suppress the background fluctuations in the flux qubit, especially in the low-frequency limit. This technique may be extensively applicable to different types of superconducting circuits, paving a way to long-term-coherence superconducting quantum information processing.

Wind-tunnel free-flight investigation of a supersonic persistence fighter

NASA Technical Reports Server (NTRS)

Hahne, David E.; Wendel, Thomas R.; Boland, Joseph R.

1993-01-01

Wind-tunnel free-flight tests have been conducted in the Langley 30- by 60-Foot Wind Tunnel to examine the high-angle-of-attack stability and control characteristics and control law design of a supersonic persistence fighter (SSPF) at 1 g flight conditions. In addition to conventional control surfaces, the SSPF incorporated deflectable wingtips (tiperons) and pitch and yaw thrust vectoring. A direct eigenstructure assignment technique was used to design control laws to provide good flying characteristics well into the poststall angle-of-attack region. Free-flight tests indicated that it was possible to blend effectively conventional and unconventional control surfaces to achieve good flying characteristics well into the poststall angle-of-attack region.

Reproducibility of apatite fission-track length data and thermal history reconstruction

NASA Astrophysics Data System (ADS)

Ketcham, Richard A.; Donelick, Raymond A.; Balestrieri, Maria Laura; Zattin, Massimiliano

2009-07-01

The ability to derive detailed thermal history information from apatite fission-track analysis is predicated on the reliability of track length measurements. However, insufficient attention has been given to whether and how these measurements should be standardized. In conjunction with a fission-track workshop we conducted an experiment in which 11 volunteers measured ~ 50 track lengths on one or two samples. One mount contained Durango apatite with unannealed induced tracks, and one contained apatite from a crystalline rock containing spontaneous tracks with a broad length distribution caused by partial resetting. Results for both mounts showed scatter indicative of differences in measurement technique among the individual analysts. The effects of this variability on thermal history inversion were tested using the HeFTy computer program to model the spontaneous track measurements. A cooling-only scenario and a reheating scenario more consistent with the sample's geological history were posed. When a uniform initial length value from the literature was used, results among analysts were very inconsistent in both scenarios, although normalizing for track angle by projecting all lengths to a c-axis parallel crystallographic orientation improved some aspects of congruency. When the induced track measurement was used as the basis for thermal history inversion congruency among analysts, and agreement with inversions based on data previously collected, was significantly improved. Further improvement was obtained by using c-axis projection. Differences among inversions that persisted could be traced to differential sampling of long- and short-track populations among analysts. The results of this study, while demonstrating the robustness of apatite fission-track thermal history inversion, nevertheless point to the necessity for a standardized length calibration schema that accounts for analyst variation.

Influences of Sentence Length and Syntactic Complexity on the Speech Motor Control of Children Who Stutter

ERIC Educational Resources Information Center

MacPherson, Megan K.; Smith, Anne

2013-01-01

Purpose: To investigate the potential effects of increased sentence length and syntactic complexity on the speech motor control of children who stutter (CWS). Method: Participants repeated sentences of varied length and syntactic complexity. Kinematic measures of articulatory coordination variability and movement duration during perceptually…

Disturbance Accommodating Adaptive Control with Application to Wind Turbines

NASA Technical Reports Server (NTRS)

Frost, Susan

2012-01-01

Adaptive control techniques are well suited to applications that have unknown modeling parameters and poorly known operating conditions. Many physical systems experience external disturbances that are persistent or continually recurring. Flexible structures and systems with compliance between components often form a class of systems that fail to meet standard requirements for adaptive control. For these classes of systems, a residual mode filter can restore the ability of the adaptive controller to perform in a stable manner. New theory will be presented that enables adaptive control with accommodation of persistent disturbances using residual mode filters. After a short introduction to some of the control challenges of large utility-scale wind turbines, this theory will be applied to a high-fidelity simulation of a wind turbine.

Effects of shock strength on shock turbulence interaction

NASA Technical Reports Server (NTRS)

Lee, Sangsan

1993-01-01

Direct numerical simulation (DNS) and linear analysis (LIA) of isotropic turbulence interacting with a shock wave are performed for several upstream shock normal Mach numbers (M(sub 1)). Turbulence kinetic energy (TKE) is amplified across the shock wave, but this amplification tends to saturate beyond M(sub 1) = 3.0. TKE amplification and Reynolds stress anisotropy obtained in DNS are consistent with LIA predictions. Rapid evolution of TKE immediate downstream of the shock wave persists for all shock strengths and is attributed to the transfer between kinetic and potential modes of turbulence energy through acoustic fluctuations. Changes in energy spectra and various length scales across the shock wave are predicted by LIA, which is consistent with DNS results. Most turbulence length scales decrease across the shock. Dissipation length scale (rho-bar q(exp 3) / epsilon), however, increases slightly for shock waves with M(sub 1) less than 1.65. Fluctuations in thermodynamic variables behind the shock wave stay nearly isentropic for M(sub 1) less than 1.2 and deviate significantly from isentropy for the stronger shock waves due to large entropy fluctuation generated through the interaction.

Non-Hookean statistical mechanics of clamped graphene ribbons

NASA Astrophysics Data System (ADS)

Bowick, Mark J.; Košmrlj, Andrej; Nelson, David R.; Sknepnek, Rastko

2017-03-01

Thermally fluctuating sheets and ribbons provide an intriguing forum in which to investigate strong violations of Hooke's Law: Large distance elastic parameters are in fact not constant but instead depend on the macroscopic dimensions. Inspired by recent experiments on free-standing graphene cantilevers, we combine the statistical mechanics of thin elastic plates and large-scale numerical simulations to investigate the thermal renormalization of the bending rigidity of graphene ribbons clamped at one end. For ribbons of dimensions W ×L (with L ≥W ), the macroscopic bending rigidity κR determined from cantilever deformations is independent of the width when W <ℓth , where ℓth is a thermal length scale, as expected. When W >ℓth , however, this thermally renormalized bending rigidity begins to systematically increase, in agreement with the scaling theory, although in our simulations we were not quite able to reach the system sizes necessary to determine the fully developed power law dependence on W . When the ribbon length L >ℓp , where ℓp is the W -dependent thermally renormalized ribbon persistence length, we observe a scaling collapse and the beginnings of large scale random walk behavior.

Status and conservation of the fish fauna of the Alabama River system

USGS Publications Warehouse

Freeman, Mary C.; Irwin, E.R.; Burkhead, N.M.; Freeman, B.J.; Bart, H.L.; Rinne, John N.; Hughes, Robert M.; Calamusso, Bob

2005-01-01

The Alabama River system, comprising the Alabama, Coosa, and Tallapoosa subsystems, forms the eastern portion of the Mobile River drainage. Physiographic diversity and geologic history have fostered development in the Alabama River system of globally significant levels of aquatic faunal diversity and endemism. At least 184 fishes are native to the system, including at least 33 endemic species. During the past century, dam construction for hydropower generation and navigation resulted in 16 reservoirs that inundate 44% of the length of the Alabama River system main stems. This extensive physical and hydrologic alteration has affected the fish fauna in three major ways. Diadromous and migratory species have declined precipitously. Fish assemblages persisting downstream from large main-stem dams have been simplified by loss of species unable to cope with altered flow and water quality regimes. Fish populations persisting in the headwaters and in tributaries to the mainstem reservoirs are now isolated and subjected to effects of physical and chemical habitat degradation. Ten fishes in the Alabama River system (including seven endemic species) are federally listed as threatened or endangered. Regional experts consider at least 28 additional species to be vulnerable, threatened, or endangered with extinction. Conserving the Alabama River system fish fauna will require innovative dam management, protection of streams from effects of urbanization and water supply development, and control of alien species dispersal. Failure to manage aggressively for integrity of remaining unimpounded portions of the Alabama River system will result in reduced quality of natural resources for future generations, continued assemblage simplification, and species extinction.

Status and conservation of the fish fauna of the Alabama River system

USGS Publications Warehouse

Freeman, Mary C.; Irwin, E.R.; Burkhead, N.M.; Freeman, B.J.; Bart, H.L.

2005-01-01

The Alabama River system, comprising the Alabama, Coosa, and Tallapoosa subsystems, forms the eastern portion of the Mobile River drainage. Physiographic diversity and geologic history have fostered development in the Alabama River system of globally significant levels of aquatic faunal diversity and endemism. At least 184 fishes are native to the system, including at least 33 endemic species. During the past century, dam construction for hydropower generation and navigation resulted in 16 reservoirs that inundate 44% of the length of the Alabama River system main stems. This extensive physical and hydrologic alteration has affected the fish fauna in three major ways. Diadromous and migratory species have declined precipitously. Fish assemblages persisting downstream from large main-stem dams have been simplified by loss of species unable to cope with altered flow and water quality regimes. Fish populations persisting in the headwaters and in tributaries to the mainstem reservoirs are now isolated and subjected to effects of physical and chemical habitat degradation. Ten fishes in the Alabama River system (including seven endemic species) are federally listed as threatened or endangered. Regional experts consider at least 28 additional species to be vulnerable, threatened, or endangered with extinction. Conserving the Alabama River system fish fauna will require innovative dam management, protection of streams from effects of urbanization and water supply development, and control of alien species dispersal. Failure to manage aggressively for integrity of remaining unimpounded portions of the Alabama River system will result in reduced quality of natural resources for future generations, continued assemblage simplification, and species extinctions. ?? 2005 by the American Fisheries Society.

Increased frequency of Epstein-Barr virus excretion in patients with new daily persistent headaches.

PubMed

Diaz-Mitoma, F; Vanast, W J; Tyrrell, D L

1987-02-21

In a case-control study 27 (84%) of 32 patients with new daily persistent headaches (NDPH) and 8 (25%) of 32 controls had evidence of Epstein-Barr virus (EBV) "active" infection, as demonstrated by EBV excretion and/or early antigen titre above 1:32. 20 (62%) patients and 4 (12%) controls were excreting EBV in the oropharynx, as determined by a dot hybridisation assay. The mean titre of IgG antibodies to early antigen was significantly higher in patients than controls. EBV reactivation may be important in the pathogenesis of NDPH. Alternatively, patients with NDPH may be unusually prone to EBV reactivation.

Dynamics of a Subterranean Trophic Cascade in Space and Time

PubMed Central

Ram, Karthik; Gruner, Daniel S.; McLaughlin, John P.; Preisser, Evan L.; Strong, Donald R.

2008-01-01

Trophic cascades, whereby predators indirectly benefit plant biomass by reducing herbivore pressure, form the mechanistic basis for classical biological control of pest insects. Entomopathogenic nematodes (EPN) are lethal to a variety of insect hosts with soil-dwelling stages, making them promising biocontrol agents. EPN biological control programs, however, typically fail because nematodes do not establish, persist and/or recycle over multiple host generations in the field. A variety of factors such as local abiotic conditions, host quantity and quality, and rates of movement affect the probability of persistence. Here, we review results from 13 years of study on the biology and ecology of an endemic population of Heterorhabditis marelatus (Rhabditida: Heterorhabditidae) in a California coastal prairie. In a highly seasonal abiotic environment with intrinsic variation in soils, vegetation structure, and host availability, natural populations of H. marelatus persisted at high incidence at some but not all sites within our study area. Through a set of field and lab experiments, we describe mechanisms and hypotheses to understand the persistence of H. marelatus. We suggest that further ecological study of naturally occurring EPN populations can yield significant insight to improve the practice and management of biological control of soil-dwelling insect pests. PMID:19259524

SUSTAINABILITY, OPTION, THEORY, AND QUALITY CONTROL

EPA Science Inventory

Recently, Cabezas and Fath (2000) hypothesized that constant Fisher Information is a necessary condition for the persistence, i.e., sustainability of a dynamic regime of a system. A sustainable dynamic regime is one that persists and an unsustainable regime is one that does not ...

Plasticity-Based Adaptive Cognitive Remediation (PACR) for OIF/OEF Veterans: A Randomized Controlled Trial

DTIC Science & Technology

2015-10-01

TERMS traumatic brain injury, tbi, concussion , persistent post- concussive symptoms, cognition, cognitive function, cognitive rehabilitation...veterans and active duty military personnel suffering from persistent post- concussive symptoms (PPCS) following mild traumatic brain injury (mTBI) at

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.

Current Understanding of Perfluoroalkyl Acid Toxicology ...

EPA Pesticide Factsheets

The perfluoroalkyl acids (PFAAs) are a family of organic chemicals consisting of a perfluorinated carbon backbone (4-14 carbons in length) and an anionic head group (sulfonate, carboxylate or phosphonate). These compounds have excellent surface-tension reducing properties and have numerous industrial and consumer applications. However, they are chemically stable, persistent in the environment, ubiquitously distributed, and present in humans and wildlife. Two issues must be considered regarding PFAA toxicology: pharmacokinetics and potency of the chemicals. The rates of PFAA clearance and their body burden accumulation are dependent on carbon-chain length and animal species. In general, the serum half-life of PFAAs increases with chain length in both rodents and humans, but the estimates in humans are markedly higher than those in laboratory animals. Recent studies with laboratory animal models have indicated a number of toxic effects of PFAAs, including tumor induction, hepatotoxicity, developmental toxicity, immunotoxicity, neurotoxicity and endocrine disruption. The modes of PFAA actions are not well understood, but are thought to involve, in part, activation of nuclear receptor signals (such as peroxisome proliferator-activated receptor-a, PPARa). Based on PPARa activation, potency of PFAAs increases with carbon-chain length, carboxylates are stronger than sulfonates, and mouse receptor is more reactive than human receptor. Adverse effects of perfluorophospho

Neuronal control of locomotor handedness in Drosophila.

PubMed

Buchanan, Sean M; Kain, Jamey S; de Bivort, Benjamin L

2015-05-26

Genetically identical individuals display variability in their physiology, morphology, and behaviors, even when reared in essentially identical environments, but there is little mechanistic understanding of the basis of such variation. Here, we investigated whether Drosophila melanogaster displays individual-to-individual variation in locomotor behaviors. We developed a new high-throughout platform capable of measuring the exploratory behavior of hundreds of individual flies simultaneously. With this approach, we find that, during exploratory walking, individual flies exhibit significant bias in their left vs. right locomotor choices, with some flies being strongly left biased or right biased. This idiosyncrasy was present in all genotypes examined, including wild-derived populations and inbred isogenic laboratory strains. The biases of individual flies persist for their lifetime and are nonheritable: i.e., mating two left-biased individuals does not yield left-biased progeny. This locomotor handedness is uncorrelated with other asymmetries, such as the handedness of gut twisting, leg-length asymmetry, and wing-folding preference. Using transgenics and mutants, we find that the magnitude of locomotor handedness is under the control of columnar neurons within the central complex, a brain region implicated in motor planning and execution. When these neurons are silenced, exploratory laterality increases, with more extreme leftiness and rightiness. This observation intriguingly implies that the brain may be able to dynamically regulate behavioral individuality.

Persistent post-traumatic headache vs. migraine: an MRI study demonstrating differences in brain structure.

PubMed

Schwedt, Todd J; Chong, Catherine D; Peplinski, Jacob; Ross, Katherine; Berisha, Visar

2017-08-22

The majority of individuals with post-traumatic headache have symptoms that are indistinguishable from migraine. The overlap in symptoms amongst these individuals raises the question as to whether post-traumatic headache has a unique pathophysiology or if head trauma triggers migraine. The objective of this study was to compare brain structure in individuals with persistent post-traumatic headache (i.e. headache lasting at least 3 months following a traumatic brain injury) attributed to mild traumatic brain injury to that of individuals with migraine. Twenty-eight individuals with persistent post-traumatic headache attributed to mild traumatic brain injury and 28 individuals with migraine underwent brain magnetic resonance imaging on a 3 T scanner. Regional volumes, cortical thickness, surface area and curvature measurements were calculated from T1-weighted sequences and compared between subject groups using ANCOVA. MRI data from 28 healthy control subjects were used to interpret the differences in brain structure between migraine and persistent post-traumatic headache. Differences in regional volumes, cortical thickness, surface area and brain curvature were identified when comparing the group of individuals with persistent post-traumatic headache to the group with migraine. Structure was different between groups for regions within the right lateral orbitofrontal lobe, left caudal middle frontal lobe, left superior frontal lobe, left precuneus and right supramarginal gyrus (p < .05). Considering these regions only, there were differences between individuals with persistent post-traumatic headache and healthy controls within the right lateral orbitofrontal lobe, right supramarginal gyrus, and left superior frontal lobe and no differences when comparing the migraine cohort to healthy controls. In conclusion, persistent post-traumatic headache and migraine are associated with differences in brain structure, perhaps suggesting differences in their underlying pathophysiology. Additional studies are needed to further delineate similarities and differences in brain structure and function that are associated with post-traumatic headache and migraine and to determine their specificity for each of the headache types.

A retrospective study of treatment persistence and adherence to α-blocker plus antimuscarinic combination therapies, in men with LUTS/BPH in the Netherlands.

PubMed

Drake, Marcus J; Bowditch, Sally; Arbe, Emilio; Hakimi, Zalmai; Guelfucci, Florent; Amri, Ikbel; Nazir, Jameel

2017-05-22

To assess treatment persistence and adherence in men ≥45 years of age with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH), using prescription records from the Netherlands IMS Lifelink™ LRx database. In this retrospective, observational cohort study, we identified men who received combination therapy with an α-blocker plus an antimuscarinic (e.g. solifenacin or tolterodine) between 1 November 2013 and 31 October 2014. Treatment could be received as a fixed-dose combination (FDC) tablet or as two drugs administered together (concomitant therapy), if both combination drugs were prescribed within 30 days. The primary objective was to assess treatment persistence, defined as the time from initiation of combination therapy until first discontinuation of the FDC or at least one of the drugs given concomitantly (i.e. ≥30 days without prescription renewal). Subgroup and sensitivity analyses were conducted to assess persistence by antimuscarinic agent, and with different gap lengths used to define discontinuation (45, 60 and 90 days), respectively. A total of 1891 men received an α-blocker plus an antimuscarinic (FDC, N = 665; concomitant therapy, N = 1226). Median time to discontinuation was significantly longer with FDC versus concomitant therapy (414 vs. 112 days; adjusted hazard ratio [HR] 2.04, 95% confidence interval 1.77, 2.35; p < 0.0001). Persistence at 12 months (51.3% vs. 29.9%) was also significantly greater with FDC compared with concomitant therapy. Assessment of antimuscarinic subgroups showed that median time to discontinuation was longest with solifenacin combinations (214 days) compared with other antimuscarinic combinations (range, 47-164 days; adjusted HR range, 1.27-1.77, p = 0.037). No observable impact on treatment persistence was found by adjusting the gaps used to define discontinuation. This study of real-world evidence of men with LUTS/BPH treated with α-blocker plus antimuscarinic combination therapy in the Netherlands showed that treatment persistence was significantly greater in those who received a FDC tablet compared with combination therapy given concomitantly. The study also shows that treatment persistence was extended in men who received combination therapy containing solifenacin compared with other antimuscarinics. Overall, these findings may be useful for prescribers, as improved persistence on-treatment may translate into improved outcomes for men with LUTS/BPH. Further study is warranted to establish the key drivers of persistence in men receiving combination therapy for LUTS/BPH.

Scaling Analysis of Tide Gauge Data from the Atlantic, Gulf of Mexico, and Pacific Coasts of the United States

NASA Astrophysics Data System (ADS)

Barton, C. C.; Smigelski, J. R.; Tebbens, S. F.

2008-12-01

Most coastal regions are subject to inundation due to many periodic and non-periodic inputs including for example: diurnal and semi diurnal tides, storms, tsunamis, and global sea level change. Tide guage data provide a frequently sampled long term record of fluctuations in water level. A power-spectral-density analysis of tidal gauge data is used to quantify persistence (degree of internal correlation over various time intervals) in terms of the scaling exponent β and to identify temporal changes in persistence. The stations are located at different proximity to the open ocean, including bays, harbors, and channels. The datasets are from the NOAA CO-OPS Verified Hourly Station Datum. The length of the data sets ranges from 3 years to 101 years. The hourly data sets are decimated to one record every four hours. All data sets analyzed show three distinct regions of persistence with two inflection points at approximately one day and five days. For times less than one day, the scaling exponent ranges between 0 < β < 2.6. For the time interval 1 to 5 days, the scaling exponent ranges between 1.1 < β < 2.1. For times greater than 5 days, the scaling exponent ranges between 0.4 < β < 0.9. Persistence generally decreases as period increases but is stable between the inflection points. At Duck, NC, long term persistence in the tide gauge signal is 0.6 as compared to 0.9 for the biweekly shoreline position signal over twenty years, suggesting a strong correlation between the two and the possibility of using tide gauge data to quantify nearby shoreline mobility over similar time intervals.

Frequency of LCT -13910C>T single nucleotide polymorphism associated with adult-type hypolactasia/lactase persistence among Brazilians of different ethnic groups.

PubMed

Mattar, Rejane; Monteiro, Maria S; Villares, Cibele A; Santos, Aníbal F; Silva, Joyce M K; Carrilho, Flair J

2009-10-02

Adult-type hypolactasia, the physiological decline of lactase some time after weaning, was previously associated with the LCT -13910C>T polymorphism worldwide except in Africa. Lactase non-persistence is the most common phenotype in humans, except in northwestern Europe with its long history of pastoralism and milking. We had previously shown association of LCT -13910C>T polymorphism with adult-type hypolactasia in Brazilians; thus, we assessed its frequency among different Brazilian ethnic groups. We investigated the ethnicity-related frequency of this polymorphism in 567 Brazilians [mean age, 42.1 +/- 16.8 years; 157 (27.7%) men]; 399 (70.4%) White, 50 (8.8%) Black, 65 (11.5%) Brown, and 53 (9.3%) Japanese-Brazilian. DNA was extracted from leukocytes; LCT -13910C>T polymorphism was analyzed by PCR-restriction fragment length polymorphism. Prevalence of the CC genotype associated with hypolactasia was similar (57%) among White and Brown groups; however, prevalence was higher among Blacks (80%) and those of Japanese descent (100%). Only 2 (4%) Blacks had TT genotype, and 8 (16%) had the CT genotype. Assuming an association between CC genotype and hypolactasia, and CT and TT genotypes with lactase persistence, 356 (62.8%) individuals had hypolactasia and 211 (37.2%) had lactase persistence. The White and Brown groups had the same hypolactasia prevalence (approximately 57%); nevertheless, was 80% among Black individuals and 100% among Japanese-Brazilians (P < 0.01). The lactase persistence allele, LCT -13910T, was found in about 43% of both White and Brown and 20% of the Black Brazilians, but was absent among all Japanese Brazilians studied.

Chest pain control with kinesiology taping after lobectomy for lung cancer: initial results of a randomized placebo-controlled study.

PubMed

Imperatori, Andrea; Grande, Annamaria; Castiglioni, Massimo; Gasperini, Laura; Faini, Agnese; Spampatti, Sebastiano; Nardecchia, Elisa; Terzaghi, Lorena; Dominioni, Lorenzo; Rotolo, Nicola

2016-08-01

Kinesiology taping (KT) is a rehabilitative technique performed by the cutaneous application of a special elastic tape. We tested the safety and efficacy of KT in reducing postoperative chest pain after lung lobectomy. One-hundred and seventeen consecutive patients, both genders, age 18-85, undergoing lobectomy for lung cancer between January 2013 and July 2015 were initially considered. Lobectomies were performed by the same surgical team, with thoracotomy or video-assisted thoracoscopic surgery (VATS) access. Exclusion criteria (n = 25 patients) were: previous KT exposure, recent trauma, pre-existing chest pain, lack of informed consent, >24-h postoperative intensive care unit treatment. After surgery, the 92 eligible patients were randomized to KT experimental group (n = 46) or placebo control group (n = 46). Standard postoperative analgesia was administered in both groups (paracetamol/non-steroidal anti-inflammatory drugs, epidural analgesia including opioids), with supplemental analgesia boluses at patient request. On postoperative day 1 in addition, in experimental group patients a specialized physiotherapist applied KT, with standardized tape length, tension and shape, over three defined skin areas: at the chest access site pain trigger point; over the ipsilateral deltoid/trapezius; lower anterior chest. In control group, usual dressing tape mimicking KT was applied over the same areas, as placebo. Thoracic pain severity score [visual analogue scale (VAS) ranging 0-10] was self-assessed by all patients on postoperative days 1, 2, 5, 8, 9 and 30. The KT group and the control group had similar demographics, lung cancer clinico-pathological features and thoracotomy/VATS ratio. Postoperatively, the two groups also resulted similar in supplemental analgesia, complication rate, mean duration of chest drainage and length of stay. There were no adverse events with KT application. After tape application, KT patients reported overall less thoracic pain than the control group, the difference being significant on postoperative day 5 [median VAS, 2 (interquartile range, 1-3) vs 3 (2-5), P < 0.01] and day 8 [median VAS, 1 (0-2) vs 2 (1-3), P < 0.05]. Moreover, on postoperative day 30 persistence of chest pain (VAS ≥3) was reported less frequently by the KT group than by the control group (7 vs 24%; P = 0.03). KT after lung lobectomy is a safe and effective auxiliary technique for chest pain control. ISRCTN37253470. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Nocturnal temperature controlled laminar airflow for treating atopic asthma: a randomised controlled trial

PubMed Central

Boyle, Robert J; Pedroletti, Christophe; Wickman, Magnus; Bjermer, Leif; Valovirta, Erkka; Dahl, Ronald; Von Berg, Andrea; Zetterström, Olof

2011-01-01

Objective To determine whether environmental control using nocturnal temperature controlled laminar airflow (TLA) treatment could improve the quality of life of patients with persistent atopic asthma. Design Randomised, double-blind, placebo-controlled, parallel-group trial. Setting Nineteen European asthma clinics. Participants 312 patients aged 7–70 with inadequately controlled persistent atopic asthma. Main outcome measure Proportion of patients with an increase of ≥0.5 points in asthma quality of life score after 1 year of treatment. Results TLA devices were successfully installed in the bedrooms of 282 (90%) patients included in the primary efficacy analysis. There was a difference in treatment response rate between active (143 of 189, 76%) and placebo (56 of 92, 61%) groups, difference 14.8% (95% CI 3.1 to 26.5, p=0.02).3 In patients aged ≥12, on whom the study was powered, the difference in response rate was similar-active 106 of 143 (74%), placebo 42 of 70 (60%), difference 14.1% (0.6 to 27.7, p=0.059). There was a difference between groups in fractional exhaled nitric oxide change of −7.1 ppb (−13.6 to −0.7, p=0.03). Active treatment was associated with less increase in cat-specific IgE than placebo. There was no difference in adverse event rates between treatment groups. Conclusion Inhalant exposure reduction with TLA improves quality of life, airway inflammation and systemic allergy in patients with persistent atopic asthma. TLA may be a treatment option for patients with inadequately controlled persistent atopic asthma. Trial registration number Clinical Trials NCT00986323. PMID:22131290

Effect of medication burden on persistent use of lipid-lowering drugs among patients with hypertension.

PubMed

Robertson, Teisha A; Cooke, Catherine E; Wang, Jingshu; Shaya, Fadia T; Lee, Helen Y

2008-11-01

To determine the effect of medication burden on persistent use of newly added lipid-lowering (LL) drugs among patients with hypertension. This retrospective database study used medical and pharmacy claims from a mid-Atlantic managed care organization. The cohort was obtained from continuous member enrollment in pharmacy and medical benefits from January 1, 2003, to December 31, 2005. Prescription claims were obtained for 18 months following the date of the first filled LL prescription (ie, index date). Patients were stratified into patients who changed LL drug or strength (group 1) and patients who did not change LL drug or strength (group 2). The primary outcome measure was persistence to newly added LL therapy. Persistence was defined by the length of time a member remained on therapy following the index date. The secondary outcome measure was the medication possession ratio (MPR). The MPR was calculated as the ratio of the sum of the days' supply of prescription filled divided by the number of days filled, plus the days' supply for the final prescription fill. Associations between the daily medication burden, defined as the number of unique drug products, and the outcome measures were analyzed. In the cohort of 3058 patients, the mean medication burden was 2.9 medications. Medication burden was positively associated with persistence and MPR through 18 months. Patients who had greater medication burden had longer persistence (P <.001). Likewise, patients who had greater medication burden had higher MPRs and were more likely to be considered adherent (MPR, >80%) (P < .001 for both). Patients with higher medication burden had greater adherence to newly added LL therapy. Medication burden should not deter clinicians from adding LL therapy. Among patients with added LL therapy, more attention should focus on patients who have changes to their LL regimen compared with patients who continue on the same LL prescription.

Persistently high psychological well-being predicts better HDL cholesterol and triglyceride levels: findings from the midlife in the U.S. (MIDUS) longitudinal study.

PubMed

Radler, Barry T; Rigotti, Attilio; Ryff, Carol D

2018-01-03

Psychological correlates of blood lipid levels have been previously evaluated mostly in cross sectional studies. However, prospectively measured psychological factors might also predict favorable blood lipid profiles, thereby indicating a healthy mind/body interplay that is associated with less disease, better health and longer lives. This paper examined whether longitudinal profiles of psychological well-being over 9-10 years are predictors of blood lipid profiles. Using the MIDUS (Midlife in the U.S.) biological subsample (n = 1054, aged 34 to 84, 55% female), cross-time trajectories of well-being were linked with three lipid outcomes (i.e., HDL cholesterol, triglycerides, and LDL cholesterol), measured for the first time at the 2nd wave of the study. Most adults showed largely stable profiles of well-being, albeit at different levels. Some showed persistently high well-being over time, while others revealed persistently low or moderate well-being. After adjusting for the effect of demographics, health behaviors, medications, and insulin resistance, adults with persistently high levels of environmental mastery and self-acceptance-two components of psychological well-being-had significantly higher levels of HDL as well as significantly lower levels of triglycerides compared to adults with persistently low levels of well-being. Converging with prior findings, no association was found between well-being and LDL cholesterol. Over 9-10 years, persistently high levels of psychological well-being measures predicted high HDL cholesterol and low triglycerides. These findings add longitudinal evidence to the growing body of research showing that positive psychological factors are linked with better lipoprotein profiles. A better blood lipid profile, particularly higher HDL-C, may be key in mediating how psychological well-being positively impacts health and length of life. Additional research is required to further validate this hypothesis as well as to establish potential underlying mechanisms.

Structural abnormalities and persistent complaints after an ankle sprain are not associated: an observational case control study in primary care.

PubMed

van Ochten, John M; Mos, Marinka C E; van Putte-Katier, Nienke; Oei, Edwin H G; Bindels, Patrick J E; Bierma-Zeinstra, Sita M A; van Middelkoop, Marienke

2014-09-01

Persistent complaints are very common after a lateral ankle sprain. To investigate possible associations between structural abnormalities on radiography and MRI, and persistent complaints after a lateral ankle sprain. Observational case control study on primary care patients in general practice. Patients were selected who had visited their GP with an ankle sprain 6-12 months before the study; all received a standardised questionnaire, underwent a physical examination, and radiography and MRI of the ankle. Patients with and without persistent complaints were compared regarding structural abnormalities found on radiography and MRI; analyses were adjusted for age, sex, and body mass index. Of the 206 included patients, 98 had persistent complaints and 108 did not. No significant differences were found in structural abnormalities between patients with and without persistent complaints. In both groups, however, many structural abnormalities were found on radiography in the talocrural joint (47.2% osteophytes and 45.1% osteoarthritis) and the talonavicular joint (36.5% sclerosis). On MRI, a high prevalence was found of bone oedema (33.8%) and osteophytes (39.5) in the talocrural joint; osteophytes (54.4%), sclerosis (47.2%), and osteoarthritis (55.4%, Kellgren and Lawrence grade >1) in the talonavicular joint, as well as ligament damage (16.4%) in the anterior talofibular ligament. The prevalence of structural abnormalities is high on radiography and MRI in patients presenting in general practice with a previous ankle sprain. There is no difference in structural abnormalities, however, between patients with and without persistent complaints. Using imaging only will not lead to diagnosis of the explicit reason for the persistent complaint. © British Journal of General Practice 2014.

Structural abnormalities and persistent complaints after an ankle sprain are not associated: an observational case control study in primary care

PubMed Central

van Ochten, John M; Mos, Marinka CE; van Putte-Katier, Nienke; Oei, Edwin HG; Bindels, Patrick JE; Bierma-Zeinstra, Sita MA; van Middelkoop, Marienke

2014-01-01

Background Persistent complaints are very common after a lateral ankle sprain. Aim To investigate possible associations between structural abnormalities on radiography and MRI, and persistent complaints after a lateral ankle sprain. Design and setting Observational case control study on primary care patients in general practice. Method Patients were selected who had visited their GP with an ankle sprain 6–12 months before the study; all received a standardised questionnaire, underwent a physical examination, and radiography and MRI of the ankle. Patients with and without persistent complaints were compared regarding structural abnormalities found on radiography and MRI; analyses were adjusted for age, sex, and body mass index. Results Of the 206 included patients, 98 had persistent complaints and 108 did not. No significant differences were found in structural abnormalities between patients with and without persistent complaints. In both groups, however, many structural abnormalities were found on radiography in the talocrural joint (47.2% osteophytes and 45.1% osteoarthritis) and the talonavicular joint (36.5% sclerosis). On MRI, a high prevalence was found of bone oedema (33.8%) and osteophytes (39.5) in the talocrural joint; osteophytes (54.4%), sclerosis (47.2%), and osteoarthritis (55.4%, Kellgren and Lawrence grade >1) in the talonavicular joint, as well as ligament damage (16.4%) in the anterior talofibular ligament. Conclusion The prevalence of structural abnormalities is high on radiography and MRI in patients presenting in general practice with a previous ankle sprain. There is no difference in structural abnormalities, however, between patients with and without persistent complaints. Using imaging only will not lead to diagnosis of the explicit reason for the persistent complaint. PMID:25179068

Psychopathological, temperamental, and characteristic factors in adults with remaining childhood attention-deficit hyperactivity symptoms.

PubMed

Kim, Kyoung Min; Nam, Sojeong; Kim, Soo Yeon; Lee, Soo Min; Choi, Jae-Won; Kang, Taewoong; Kim, Jun Won

2017-09-01

To investigate differences in psychopathological, temperamental and characteristic factors between young adults with and without persistent Attention-Deficit Hyperactivity disorder (ADHD) symptoms. A total of 429 university students were divided into three groups: persistent adult ADHD (n = 53), only childhood ADHD (n = 56) and healthy controls (n = 320). The Korean Adult ADHD Scale, Korean Wender-Utah Rating Scale, Beck Depression Inventory-II, Beck Anxiety Inventory, Barratt Impulsiveness Scale, Korean Young Internet Addiction Scale, and Temperament Character Inventory-Revised (TCI-R; based on Cloninger's seven factor model of temperament and character) were used to evaluate psychopathological factors. Participants with persistent adult ADHD symptoms had significantly higher levels of childhood ADHD, depression, anxiety and the Internet addiction symptoms than did the only-childhood ADHD and control groups. The adult ADHD group also had significantly higher tendencies toward novelty seeking, harm avoidance, and self-transcendence, as well as low self-directedness and cooperativeness. Results suggest that persistent ADHD is associated with several unfavourable psychopathological, temperamental and characteristic factors. Therefore, thorough evaluation of these factors for childhood ADHD could help predict prognoses and provide treatment plans for preventing persistent ADHD into adulthood.

Investigation to identify a resource-efficient case-control methodology for determining antibiotics associated with Clostridium difficile infection.

PubMed

Chung, Philip; Currie, Brian; Guo, Yi; Talansky, Moshe; Brown, Shakara; Ostrowsky, Belinda

2014-10-01

Antimicrobial exposure remains an important risk factor for developing Clostridium difficile infection (CDI). Efficient method to identify antibiotics associated with CDI is important for formulating strategies to curtail their use. As a prelude to a more extensive Agency for Healthcare Research and Quality-funded project (Evaluation & Research on Antimicrobial Stewardship's Effect on Clostridium difficile), we undertook an exploratory evaluation to determine a resource-efficient method for identifying antibiotic targets for antimicrobial stewardship interventions. The study compared a series of 6 focused case-control studies. Cases consisted of patients with laboratory-confirmed CDI admitted from July-October 2009. Controls were selected from patients without CDI hospitalized during the same period. Five groups of controls were matched to cases (2:1 ratio) using group-specific matching criteria, including admission date, age, type of admission, length of stay (LOS) to discharge, and/or LOS to CDI diagnosis. The final control group was selected from patients who received antibiotics during hospitalization. Data, including demographics and antibiotic usage, were compared between case and control groups. A total of 126 cases were matched to 6 groups of 252 controls. For control groups 1-5, the use of piperacillin and tazobactam, ceftriaxone or cefepime, ciprofloxacin or moxifloxacin, intravenous vancomycin, azithromycin, and antibiotics of last resort were significantly more frequent in case than control patients. For the final control group, the associations between ceftriaxone or cefepime, and ciprofloxacin or moxifloxacin use and CDI no longer persisted. This could in part be explained by differences in comorbidities between case and control patients even with stringent matching criteria. Use of a simple matching strategy to conduct case-control studies is an efficient and feasible compromise strategy, especially in resource-limited settings, to identify high-risk antibiotics associated with CDI. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

A four-year follow-up controlled study of stress response and symptom persistence in Brazilian children and adolescents with attention deficit disorder and hyperactivity (ADHD).

PubMed

Palma, Sonia Maria Motta; Natale, Ana Carolina Motta Palma; Calil, Helena Maria

2015-12-15

This study evaluated children and adolescents with Attention Deficit Disorder andHyperactivity Disorder (ADHD), reassessing them at a four-year follow-up. Their cortisol response to a stress stimulus was measured twice. ADHD symptom persistence, development of comorbidities, and psychostimulant usage were also reassessed. The initial sample consisted of 38 ADHD patients and 38 healthy controls, age ranging 6-14. At the follow-up, there were 37 ADHD patients and 22 healthy controls, age ranging 10-18. ADHD was classified as persistent if the patients fulfilled all DSM IV criteria for syndromic or subthreshold or had functional impairment. Salivary cortisol samples were collected prior to the application of a cognitive stressor (Continuous Performance Test - CPT), and at three time intervals afterwards at baseline and at the follow-up. Their reassessment showed that 75% had persistent symptoms, psychiatric comorbidities (oppositional defiant and behavioral disorders), functional and academic impairement. Only seven patients were on medication. The ADHD group's cortisol levels were lower than those measured four years earlier, but cortisol concentrations were similar for both ADHD and control groups at the four-year follow-up. The cortisol results suggest that HPA axis reactivity could be a marker differentiating ADHD from ADHD with comorbidities. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Proteomic analysis of Mycoplasma gallisepticum vaccine strain F

USDA-ARS?s Scientific Manuscript database

The persistence and displacement abilities of the Mycoplasma gallisepticum vaccine strain F (F-strain) are well documented. Understanding the mechanism(s) of colonization and persistence of F-strain will aid in the current intervention strategies to diagnose and control MG infections in poultry. In ...

Evaluation of inflammatory markers interleukin-6 (IL-6) and matrix metalloproteinase-9 (MMP-9) in asthma.

PubMed

Naik, Srilata Puru; P A, Mahesh; B S, Jayaraj; Madhunapantula, SubbaRao V; Jahromi, Sarah Raeiszadeh; Yadav, Manish Kumar

2017-08-01

Even though IL-6 and MMP-9 are associated with airway inflammation in asthma, there is paucity of data in Indian population. To determine the levels of IL-6 and MMP-9 in the serum of patients suffering from asthma, and correlate with (a) disease severity, as per GINA guidelines; (b) clinical phenotypes; and (c) response to treatment. The levels of IL-6 and MMP-9 were compared between moderate persistent asthma (n = 25), severe persistent asthma (n = 25) and normal controls (n = 30). IL-6 and MMP-9 were measured by ELISA (R&D Systems Inc., USA and Canada) and compared between controls and asthmatics and between groups of different asthma severity, clinical variables, spirometry, and allergen sensitization. Spirometry was repeated after 2 months of ICS+LABA to assess response to treatment in relation to baseline IL-6 and MMP-9 levels. We observed a significant difference in both IL-6 and MMP-9 levels among asthmatics versus controls (p < 0.001), moderate versus severe persistent asthma (p < 0.001). A significant negative correlation was observed between MMP-9 and pre-bronchodilator FEV 1 and FVC, but not with IL-6. There was no association between IL-6 and MMP-9 with asthma duration, total IgE, AEC, number of allergens sensitized and degree of sensitization. No significant correlation (p > 0.5) was observed with IL-6 and MMP-9 levels and FEV 1 improvement after 2 months of ICS+LABA. Higher levels of IL-6 and MMP-9 were observed in asthmatics as compared to controls and in severe persistent asthma as compared to moderate persistent asthma, higher levels of MMP-9 was associated with lower lung functions.

Relationship of Personality Disorders to the Course of Major Depressive Disorder in a Nationally Representative Sample

PubMed Central

Skodol, Andrew E.; Grilo, Carlos M.; Keyes, Katherine; Geier, Timothy; Grant, Bridget F.; Hasin, Deborah S.

2011-01-01

Objective The purpose of this study was to examine the effects of specific personality disorder co-morbidity on the course of major depressive disorder in a nationally-representative sample. Method Data were drawn from 1,996 participants in a national survey. Participants who met criteria for major depressive disorder at baseline in face-to-face interviews (2001–2002) were re-interviewed three years later (2004–2005) to determine persistence and recurrence. Predictors included all DSM-IV personality disorders. Control variables included demographic characteristics, other Axis I disorders, family and treatment histories, and previously established predictors of the course of major depressive disorder. Results 15.1% of participants had persistent major depressive disorder and 7.3% of those who remitted had a recurrence. Univariate analyses indicated that avoidant, borderline, histrionic, paranoid, schizoid, and schizotypal personality disorders all elevated the risk for persistence. With Axis I co-morbidity controlled, all but histrionic personality disorder remained significant. With all other personality disorders controlled, borderline and schizotypal remained significant predictors. In final, multivariate analyses that controlled for age at onset of major depressive disorder, number of previous episodes, duration of current episode, family history, and treatment, borderline personality disorder remained a robust predictor of major depressive disorder persistence. Neither personality disorders nor other clinical variables predicted recurrence. Conclusions In this nationally-representative sample of adults with major depressive disorder, borderline personality disorder robustly predicted persistence, a finding that converges with recent clinical studies. Personality psychopathology, particularly borderline personality disorder, should be assessed in all patients with major depressive disorder, considered in prognosis, and addressed in treatment. PMID:21245088

Renal sympathetic denervation improves rate control in patients with symptomatic persistent atrial fibrillation and hypertension.

PubMed

Qiu, Min; Shan, Qijun; Chen, Chun; Geng, Jie; Guo, Jiqun; Zhou, Xiujuan; Qian, Weichong; Tang, Lijun; Yin, Yuehui

2016-02-01

The aim of this study was to investigate whether renal sympathetic denervation (RSD) improves ventricular heart rate (HR) control in patients with persistent atrial fibrillation (AF). Twenty-one patients (aged 57.5 ± 10.2 years, 76.2% male) with persistent AF and hypertension underwent RSD and completed 7-days follow-up evaluations, including 24-hour Holter monitoring (Holter), blood pressure (BP), 24-hour ambulatory BP monitoring (ABPM). Patients were grouped into tertiles of average HR at baseline Holter recording for evaluation of RSD effects on atrioventricular (AV) node (group 1: HR ≧ 90 bpm; group 2: 80 bpm ≦ HR < 90 bpm; group 3: HR < 80 bpm). All patients successfully underwent RSD without any complications. The clinical and procedural characteristics were similar in all groups of patients. No significant changes in BP were observed in the three groups before and after RSD. Compared with baseline, the average HR (Holter) of patients in group 1, 2 and 3 had a reduction of 22.6 ± 13.2 bpm (83.3 ± 4.9 vs 106.0 ± 14.6, P = 0.004), 9.7 ± 7.8 bpm (75.7 ± 7.6 vs 85.4 ± 3.7, P = 0.017) and 2.3 ± 2.9 bpm (71.4 ± 4.0 vs 73.7 ± 4.7, P = 0.089) at 7 days after RSD, respectively. RSD could improve ventricular HR control in patients with persistent AF. RSD slowed AV node conduction in baseline HR-dependent manner. RSD may become an alternative non-pharmaceutical tool for rate control in patients with persistent AF.

Risk factors for persisting measles susceptibility: a case-control study among unvaccinated orthodox Protestants.

PubMed

de Munter, Anne C; Tostmann, Alma; Hahné, Susan J M; Spaan, D Henri; van Ginkel, Rijk; Ruijs, Wilhelmina L M

2018-04-30

Measles is an infectious disease providing lifelong immunity. Epidemics periodically occur among unvaccinated orthodox Protestants in the Netherlands. During the 2013/2014 epidemic, 17% of the reported patients was over 14 years old. Apparently, they did not catch measles during the previous 1999/2000 epidemic and remained susceptible. We wanted to identify risk factors for this so-called persisting measles susceptibility, and thus risk factors for acquiring measles at older age with increased risk of complications. A case-control study was performed among unvaccinated orthodox Protestants born between 1988 and 1998; cases had measles in 2013/2014, controls during or before 1999/2000. Associations between demographic, geographical and religion-related determinants and persisting measles susceptibility were determined using univariate and multivariable logistic regression. Analyses were stratified in two age-groups: infants/toddlers and primary school-aged children during the 1999/2000 measles epidemic. In total, 204 cases and 563 controls were included. Risk factors for persisting measles susceptibility for infants/toddlers in 1999/2000 were belonging to a moderately conservative church, absence of older siblings and residency outside low vaccination coverage (LVC)-municipalities. Risk factors for primary school-aged children were residency outside LVC-municipalities and attendance of non-orthodox Protestant primary school. Unvaccinated orthodox Protestant adolescents and adults who resided outside the LVC-municipalities, did not attend an orthodox Protestant primary school, had no older siblings and belonged to a moderately conservative church were at risk for persisting measles susceptibility and, thus, for acquiring measles at older age with increased risk of complications. For this subgroup of orthodox Protestants targeted information on vaccination is recommended.

Compliant walking appears metabolically advantageous at extreme step lengths.

PubMed

Kim, Jaehoon; Bertram, John E A

2018-05-19

Humans alter gait in response to unusual gait circumstances to accomplish the task of walking. For instance, subjects spontaneously increase leg compliance at a step length threshold as step length increases. Here we test the hypothesis that this transition occurs based on the level of energy expenditure, where compliant walking becomes less energetically demanding at long step lengths. To map and compare the metabolic cost of normal and compliant walking as step length increases. 10 healthy individuals walked on a treadmill using progressively increasing step lengths (100%, 120%, 140% and 160% of preferred step length), in both normal and compliant leg walking as energy expenditure was recorded via indirect calorimetry. Leg compliance was controlled by lowering the center-of-mass trajectory during stance, forcing the leg to flex and extend as the body moved over the foot contact. For normal step lengths, compliant leg walking was more costly than normal walking gait, but compliant leg walking energetic cost did not increase as rapidly for longer step lengths. This led to an intersection between normal and compliant walking cost curves at 114% relative step length (regression analysis; r 2  = 0.92 for normal walking; r 2  = 0.65 for compliant walking). Compliant leg walking is less energetically demanding at longer step lengths where a spontaneous shift to compliant walking has been observed, suggesting the human motor control system is sensitive to energetic requirements and will employ alternate movement patterns if advantageous strategies are available. The transition could be attributed to the interplay between (i) leg work controlling body travel during single stance and (ii) leg work to control energy loss in the step-to-step transition. Compliant leg walking requires more stance leg work at normal step lengths, but involves less energy loss at the step-to-step transition for very long steps. Copyright © 2018 Elsevier B.V. All rights reserved.

Stochastic Modeling based on Dictionary Approach for the Generation of Daily Precipitation Occurrences

NASA Astrophysics Data System (ADS)

Panu, U. S.; Ng, W.; Rasmussen, P. F.

2009-12-01

The modeling of weather states (i.e., precipitation occurrences) is critical when the historical data are not long enough for the desired analysis. Stochastic models (e.g., Markov Chain and Alternating Renewal Process (ARP)) of the precipitation occurrence processes generally assume the existence of short-term temporal-dependency between the neighboring states while implying the existence of long-term independency (randomness) of states in precipitation records. Existing temporal-dependent models for the generation of precipitation occurrences are restricted either by the fixed-length memory (e.g., the order of a Markov chain model), or by the reining states in segments (e.g., persistency of homogenous states within dry/wet-spell lengths of an ARP). The modeling of variable segment lengths and states could be an arduous task and a flexible modeling approach is required for the preservation of various segmented patterns of precipitation data series. An innovative Dictionary approach has been developed in the field of genome pattern recognition for the identification of frequently occurring genome segments in DNA sequences. The genome segments delineate the biologically meaningful ``words" (i.e., segments with a specific patterns in a series of discrete states) that can be jointly modeled with variable lengths and states. A meaningful “word”, in hydrology, can be referred to a segment of precipitation occurrence comprising of wet or dry states. Such flexibility would provide a unique advantage over the traditional stochastic models for the generation of precipitation occurrences. Three stochastic models, namely, the alternating renewal process using Geometric distribution, the second-order Markov chain model, and the Dictionary approach have been assessed to evaluate their efficacy for the generation of daily precipitation sequences. Comparisons involved three guiding principles namely (i) the ability of models to preserve the short-term temporal-dependency in data through the concepts of autocorrelation, average mutual information, and Hurst exponent, (ii) the ability of models to preserve the persistency within the homogenous dry/wet weather states through analysis of dry/wet-spell lengths between the observed and generated data, and (iii) the ability to assesses the goodness-of-fit of models through the likelihood estimates (i.e., AIC and BIC). Past 30 years of observed daily precipitation records from 10 Canadian meteorological stations were utilized for comparative analyses of the three models. In general, the Markov chain model performed well. The remainders of the models were found to be competitive from one another depending upon the scope and purpose of the comparison. Although the Markov chain model has a certain advantage in the generation of daily precipitation occurrences, the structural flexibility offered by the Dictionary approach in modeling the varied segment lengths of heterogeneous weather states provides a distinct and powerful advantage in the generation of precipitation sequences.

Fear extinction, persistent disruptive behavior and psychopathic traits: fMRI in late adolescence.

PubMed

Cohn, Moran D; van Lith, Koen; Kindt, Merel; Pape, Louise E; Doreleijers, Theo A H; van den Brink, Wim; Veltman, Dick J; Popma, Arne

2016-07-01

Children diagnosed with a Disruptive Behavior Disorder (DBD, i.e. Oppositional Defiant Disorder or Conduct Disorder), especially those with psychopathic traits, are at risk of developing persistent and severe antisocial behavior. Reduced fear conditioning has been proposed to underlie persistent antisocial development. However, we have recently shown that both DBD persisters and desisters are characterized by increased fear conditioning compared with healthy controls (HCs). In this study, we investigated whether brain function during fear extinction is associated with DBD subgroup-membership and psychopathic traits. Adolescents from a childhood arrestee cohort (mean age 17.6 years, s.d. 1.4) who met criteria for a DBD diagnosis during previous assessments were re-assessed and categorized as persistent DBD (n = 25) or desistent DBD (n = 25). Functional MRI during the extinction phase of a classical fear-conditioning task was used to compare regional brain function between these subgroups and 25 matched controls. Both DBD persisters and desisters showed hyperreactivity during fear extinction, when compared with HCs. Impulsive-irresponsible psychopathic traits were positively associated with responses in the fear neurocircuitry and mediated the association between neural activation and group membership. These results suggest that fear acquisition and fear extinction deficits may provide an endophenotype for an emotionally hyperreactive subtype of antisocial development. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

The role of HIV integration in viral persistence: no more whistling past the proviral graveyard

PubMed Central

Maldarelli, Frank

2016-01-01

A substantial research effort has been directed to identifying strategies to eradicate or control HIV infection without a requirement for combination antiretroviral therapy (cART). A number of obstacles prevent HIV eradication, including low-level viral persistence during cART, long-term persistence of HIV-infected cells, and latent infection of resting CD4+ T cells. Mechanisms of persistence remain uncertain, but integration of the provirus into the host genome represents a central event in replication and pathogenesis of all retroviruses, including HIV. Analysis of HIV proviruses in CD4+ lymphocytes from individuals after prolonged cART revealed that a substantial proportion of the infected cells that persist have undergone clonal expansion and frequently have proviruses integrated in genes associated with regulation of cell growth. These data suggest that integration may influence persistence and clonal expansion of HIV-infected cells after cART is introduced, and these processes may represent key mechanisms for HIV persistence. Determining the diversity of host genes with integrants in HIV-infected cells that persist for prolonged periods may yield useful information regarding pathways by which infected cells persist for prolonged periods. Moreover, many integrants are defective, and new studies are required to characterize the role of clonal expansion in the persistence of replication-competent HIV. PMID:26829624

Effect of music-based multitask training on gait, balance, and fall risk in elderly people: a randomized controlled trial.

PubMed

Trombetti, Andrea; Hars, Mélany; Herrmann, François R; Kressig, Reto W; Ferrari, Serge; Rizzoli, René

2011-03-28

Falls occur mainly while walking or performing concurrent tasks. We determined whether a music-based multitask exercise program improves gait and balance and reduces fall risk in elderly individuals. We conducted a 12-month randomized controlled trial involving 134 community-dwelling individuals older than 65 years, who are at increased risk of falling. They were randomly assigned to an intervention group (n = 66) or a delayed intervention control group scheduled to start the program 6 months later (n = 68). The intervention was a 6-month multitask exercise program performed to the rhythm of piano music. Change in gait variability under dual-task condition from baseline to 6 months was the primary end point. Secondary outcomes included changes in balance, functional performances, and fall risk. At 6 months, there was a reduction in stride length variability (adjusted mean difference, -1.4%; P < .002) under dual-task condition in the intervention group, compared with the delayed intervention control group. Balance and functional tests improved compared with the control group. There were fewer falls in the intervention group (incidence rate ratio, 0.46; 95% confidence interval, 0.27-0.79) and a lower risk of falling (relative risk, 0.61; 95% confidence interval, 0.39-0.96). Similar changes occurred in the delayed intervention control group during the second 6-month period with intervention. The benefit of the intervention on gait variability persisted 6 months later. In community-dwelling older people at increased risk of falling, a 6-month music-based multitask exercise program improved gait under dual-task condition, improved balance, and reduced both the rate of falls and the risk of falling. Trial Registration clinicaltrials.gov Identifier: NCT01107288.

Role of microtubules in the contractile dysfunction of hypertrophied myocardium

NASA Technical Reports Server (NTRS)

Zile, M. R.; Koide, M.; Sato, H.; Ishiguro, Y.; Conrad, C. H.; Buckley, J. M.; Morgan, J. P.; Cooper, G. 4th

1999-01-01

OBJECTIVES: We sought to determine whether the ameliorative effects of microtubule depolymerization on cellular contractile dysfunction in pressure overload cardiac hypertrophy apply at the tissue level. BACKGROUND: A selective and persistent increase in microtubule density causes decreased contractile function of cardiocytes from cats with hypertrophy produced by chronic right ventricular (RV) pressure overloading. Microtubule depolymerization by colchicine normalizes contractility in these isolated cardiocytes. However, whether these changes in cellular function might contribute to changes in function at the more highly integrated and complex cardiac tissue level was unknown. METHODS: Accordingly, RV papillary muscles were isolated from 25 cats with RV pressure overload hypertrophy induced by pulmonary artery banding (PAB) for 4 weeks and 25 control cats. Contractile state was measured using physiologically sequenced contractions before and 90 min after treatment with 10(-5) mol/liter colchicine. RESULTS: The PAB significantly increased RV systolic pressure and the RV weight/body weight ratio in PAB; it significantly decreased developed tension from 59+/-3 mN/mm2 in control to 25+/-4 mN/mm2 in PAB, shortening extent from 0.21+/-0.01 muscle lengths (ML) in control to 0.12+/-0.01 ML in PAB, and shortening rate from 1.12+/-0.07 ML/s in control to 0.55+/-0.03 ML/s in PAB. Indirect immunofluorescence confocal microscopy showed that PAB muscles had a selective increase in microtubule density and that colchicine caused complete microtubule depolymerization in both control and PAB papillary muscles. Microtubule depolymerization normalized myocardial contractility in papillary muscles of PAB cats but did not alter contractility in control muscles. CONCLUSIONS: Excess microtubule density, therefore, is equally important to both cellular and to myocardial contractile dysfunction caused by chronic, severe pressure-overload cardiac hypertrophy.

Spatial confinement of active microtubule networks induces large-scale rotational cytoplasmic flow

PubMed Central

Suzuki, Kazuya; Miyazaki, Makito; Takagi, Jun; Itabashi, Takeshi; Ishiwata, Shin’ichi

2017-01-01

Collective behaviors of motile units through hydrodynamic interactions induce directed fluid flow on a larger length scale than individual units. In cells, active cytoskeletal systems composed of polar filaments and molecular motors drive fluid flow, a process known as cytoplasmic streaming. The motor-driven elongation of microtubule bundles generates turbulent-like flow in purified systems; however, it remains unclear whether and how microtubule bundles induce large-scale directed flow like the cytoplasmic streaming observed in cells. Here, we adopted Xenopus egg extracts as a model system of the cytoplasm and found that microtubule bundle elongation induces directed flow for which the length scale and timescale depend on the existence of geometrical constraints. At the lower activity of dynein, kinesins bundle and slide microtubules, organizing extensile microtubule bundles. In bulk extracts, the extensile bundles connected with each other and formed a random network, and vortex flows with a length scale comparable to the bundle length continually emerged and persisted for 1 min at multiple places. When the extracts were encapsulated in droplets, the extensile bundles pushed the droplet boundary. This pushing force initiated symmetry breaking of the randomly oriented bundle network, leading to bundles aligning into a rotating vortex structure. This vortex induced rotational cytoplasmic flows on the length scale and timescale that were 10- to 100-fold longer than the vortex flows emerging in bulk extracts. Our results suggest that microtubule systems use not only hydrodynamic interactions but also mechanical interactions to induce large-scale temporally stable cytoplasmic flow. PMID:28265076

Gait cycle analysis: parameters sensitive for functional evaluation of peripheral nerve recovery in rat hind limbs.

PubMed

Rui, Jing; Runge, M Brett; Spinner, Robert J; Yaszemski, Michael J; Windebank, Anthony J; Wang, Huan

2014-10-01

Video-assisted gait kinetics analysis has been a sensitive method to assess rat sciatic nerve function after injury and repair. However, in conduit repair of sciatic nerve defects, previously reported kinematic measurements failed to be a sensitive indicator because of the inferior recovery and inevitable joint contracture. This study aimed to explore the role of physiotherapy in mitigating joint contracture and to seek motion analysis indices that can sensitively reflect motor function. Data were collected from 26 rats that underwent sciatic nerve transection and conduit repair. Regular postoperative physiotherapy was applied. Parameters regarding step length, phase duration, and ankle angle were acquired and analyzed from video recording of gait kinetics preoperatively and at regular postoperative intervals. Stride length ratio (step length of uninjured foot/step length of injured foot), percent swing of the normal paw (percentage of the total stride duration when the uninjured paw is in the air), propulsion angle (toe-off angle subtracted by midstance angle), and clearance angle (ankle angle change from toe off to midswing) decreased postoperatively comparing with baseline values. The gradual recovery of these measurements had a strong correlation with the post-nerve repair time course. Ankle joint contracture persisted despite rigorous physiotherapy. Parameters acquired from a 2-dimensional motion analysis system, that is, stride length ratio, percent swing of the normal paw, propulsion angle, and clearance angle, could sensitively reflect nerve function impairment and recovery in the rat sciatic nerve conduit repair model despite the existence of joint contractures.

Branching, Chain Scission, and Solution Stability of Worm-Like Micelles

NASA Astrophysics Data System (ADS)

Beaucage, Greg; Vogtt, Karsten; Jiang, Hanqui

As salt is added to a simple micelle solution such as SDS or SLES, the zero shear rate specific viscosity rises rapidly followed by a maximum and decay. The rapid rise in viscosity is associated with formation of elliptical and extended chain worm-like micelles, WLMs. Entanglement of these long chain micelles leads to the viscoelastic behavior we associate with shampoo and body wash. The plateau and drop in viscosity at high salt concentrations is caused by a special type of topological branching where the branch points have no energy penalty to motion along the chain according to Cates theory. These have some similarity to catenane crosslinks. Predictive dynamic theories for WLMs rely on structural details; the diameter, persistence length, contour length, branch length, segment length between branch points, and mesh size. Further, since the contour length and other large scale features are in kinetic equilibrium, with frequent chain breakage and formation, the thermodynamics of these long chain structures are of interest both in terms of chain scission as well as in terms of the stability of the colloidal solution as a whole. Recent structural studies of WLMs using static neutron scattering based on new scattering models will be presented demonstrating that these input parameters for dynamic models of complex topological systems are quantitatively and directly available. In this context it is important to consider a comparison between dynamic features, for instance entanglement, and their static analogs, chain overlap.

Mixed-source reintroductions lead to outbreeding depression in second-generation descendents of a native North American fish

USGS Publications Warehouse

Huff, D.D.; Miller, L.M.; Chizinski, C.J.; Vondracek, B.

2011-01-01

Reintroductions are commonly employed to preserve intraspecific biodiversity in fragmented landscapes. However, reintroduced populations are frequently smaller and more geographically isolated than native populations. Mixing genetically, divergent sources are often proposed to attenuate potentially low genetic diversity in reintroduced populations that may result from small effective population sizes. However, a possible negative tradeoff for mixing sources is outbreeding depression in hybrid offspring. We examined the consequences of mixed-source reintroductions on several fitness surrogates at nine slimy sculpin (Cottus cognatus) reintroduction sites in south-east Minnesota. We inferred the relative fitness of each crosstype in the reintroduced populations by comparing their growth rate, length, weight, body condition and persistence in reintroduced populations. Pure strain descendents from a single source population persisted in a greater proportion than expected in the reintroduced populations, whereas all other crosstypes occurred in a lesser proportion. Length, weight and growth rate were lower for second-generation intra-population hybrid descendents than for pure strain and first-generation hybrids. In the predominant pure strain, young-of the-year size was significantly greater than any other crosstype. Our results suggested that differences in fitness surrogates among crosstypes were consistent with disrupted co-adapted gene complexes associated with beneficial adaptations in these reintroduced populations. Future reintroductions may be improved by evaluating the potential for local adaptation in source populations or by avoiding the use of mixed sources by default when information on local adaptations or other genetic characteristics is lacking. ?? 2011 Blackwell Publishing Ltd.

Microarray analysis of human milk cells: persistent high expression of osteopontin during the lactation period

PubMed Central

NAGATOMO, T; OHGA, S; TAKADA, H; NOMURA, A; HIKINO, S; IMURA, M; OHSHIMA, K; HARA, T

2004-01-01

To continue the search for immunological roles of breast milk, cDNA microarray analysis on cytokines and growth factors was performed for human milk cells. Among the 240 cytokine-related genes, osteopontin (OPN) gene ranked top of the expression. Real-time PCR revealed that the OPN mRNA levels in colostrum cells were approximately 100 times higher than those in PHA-stimulated peripheral blood mononuclear cells (PBMNCs), and 10 000 times higher than those in PB CD14+ cells. The median levels of OPN mRNA in early milk or mature milk cells were more than three times higher than those in colostrum cells. Western blot analysis of human milk showed appreciable expression of full-length and short form proteins of OPN. The concentrations of full-length OPN in early milk or mature milk whey continued to be higher than those in colostrum whey and plasma as assessed by ELISA. The early milk (3–7 days postpartum) contained the highest concentrations of OPN protein, while the late mature milk cells (1 years postpartum) had the highest expression of OPN mRNA of all the lactating periods. The results of immunohistochemical and immunocytochemical staining indicated that OPN-producing epithelial cells and macrophages are found in actively lactating mammary glands. These results suggest that the persistently and extraordinarily high expression of OPN in human milk cells plays a potential role in the immunological development of breast-fed infants. PMID:15373904

Clonal expansion of genome-intact HIV-1 in functionally polarized Th1 CD4+ T cells

PubMed Central

Orlova-Fink, Nina; Einkauf, Kevin; Chowdhury, Fatema Z.; Sun, Xiaoming; Harrington, Sean; Kuo, Hsiao-Hsuan; Hua, Stephane; Chen, Hsiao-Rong; Ouyang, Zhengyu; Reddy, Kavidha; Dong, Krista; Ndung’u, Thumbi; Walker, Bruce D.; Rosenberg, Eric S.; Yu, Xu G.

2017-01-01

HIV-1 causes a chronic, incurable disease due to its persistence in CD4+ T cells that contain replication-competent provirus, but exhibit little or no active viral gene expression and effectively resist combination antiretroviral therapy (cART). These latently infected T cells represent an extremely small proportion of all circulating CD4+ T cells but possess a remarkable long-term stability and typically persist throughout life, for reasons that are not fully understood. Here we performed massive single-genome, near-full-length next-generation sequencing of HIV-1 DNA derived from unfractionated peripheral blood mononuclear cells, ex vivo-isolated CD4+ T cells, and subsets of functionally polarized memory CD4+ T cells. This approach identified multiple sets of independent, near-full-length proviral sequences from cART-treated individuals that were completely identical, consistent with clonal expansion of CD4+ T cells harboring intact HIV-1. Intact, near-full-genome HIV-1 DNA sequences that were derived from such clonally expanded CD4+ T cells constituted 62% of all analyzed genome-intact sequences in memory CD4 T cells, were preferentially observed in Th1-polarized cells, were longitudinally detected over a duration of up to 5 years, and were fully replication- and infection-competent. Together, these data suggest that clonal proliferation of Th1-polarized CD4+ T cells encoding for intact HIV-1 represents a driving force for stabilizing the pool of latently infected CD4+ T cells. PMID:28628034

Clonal expansion of genome-intact HIV-1 in functionally polarized Th1 CD4+ T cells.

PubMed

Lee, Guinevere Q; Orlova-Fink, Nina; Einkauf, Kevin; Chowdhury, Fatema Z; Sun, Xiaoming; Harrington, Sean; Kuo, Hsiao-Hsuan; Hua, Stephane; Chen, Hsiao-Rong; Ouyang, Zhengyu; Reddy, Kavidha; Dong, Krista; Ndung'u, Thumbi; Walker, Bruce D; Rosenberg, Eric S; Yu, Xu G; Lichterfeld, Mathias

2017-06-30

HIV-1 causes a chronic, incurable disease due to its persistence in CD4+ T cells that contain replication-competent provirus, but exhibit little or no active viral gene expression and effectively resist combination antiretroviral therapy (cART). These latently infected T cells represent an extremely small proportion of all circulating CD4+ T cells but possess a remarkable long-term stability and typically persist throughout life, for reasons that are not fully understood. Here we performed massive single-genome, near-full-length next-generation sequencing of HIV-1 DNA derived from unfractionated peripheral blood mononuclear cells, ex vivo-isolated CD4+ T cells, and subsets of functionally polarized memory CD4+ T cells. This approach identified multiple sets of independent, near-full-length proviral sequences from cART-treated individuals that were completely identical, consistent with clonal expansion of CD4+ T cells harboring intact HIV-1. Intact, near-full-genome HIV-1 DNA sequences that were derived from such clonally expanded CD4+ T cells constituted 62% of all analyzed genome-intact sequences in memory CD4 T cells, were preferentially observed in Th1-polarized cells, were longitudinally detected over a duration of up to 5 years, and were fully replication- and infection-competent. Together, these data suggest that clonal proliferation of Th1-polarized CD4+ T cells encoding for intact HIV-1 represents a driving force for stabilizing the pool of latently infected CD4+ T cells.

Calculation of Physicochemical Properties for Short- and Medium-Chain Chlorinated Paraffins

NASA Astrophysics Data System (ADS)

Glüge, Juliane; Bogdal, Christian; Scheringer, Martin; Buser, Andreas M.; Hungerbühler, Konrad

2013-06-01

Short- and medium-chain chlorinated paraffins are potential PBT chemicals (persistent, bioaccumulative, toxic) and short-chain chlorinated paraffins are under review for inclusion in the UNEP Stockholm Convention on Persistent Organic Pollutants. Despite their high production volume of more than one million metric tonnes per year, only few data on their physicochemical properties are available. We calculated subcooled-liquid vapor pressure, subcooled-liquid solubility in water and octanol, Henry's law constant for water and octanol, as well as the octanol-water partition coefficient with the property calculation methods COSMOtherm, SPARC, and EPI Suite™, and compared the results to experimental data from the literature. For all properties, good or very good agreement between calculated and measured data was obtained for COSMOtherm; results from SPARC were in good agreement with the measured data except for subcooled-liquid water solubility, whereas EPI Suite™ showed the largest discrepancies for all properties. After critical evaluation of the three property calculation methods, a final set of recommended property data for short- and medium-chain chlorinated paraffins was derived. The calculated property data show interesting relationships with chlorine content and carbon chain length. Increasing chlorine content does not cause pronounced changes in water solubility and octanol-water partition coefficient (KOW) as long as it is below 55%. Increasing carbon chain length leads to strong increases in KOW and corresponding decreases in subcooled-liquid water solubility. The present data set can be used in further studies to assess the environmental fate and human exposure of this relevant compound class.

The Relationship Between Female Genital Cutting and Obstetric Fistulas

PubMed Central

Browning, Andrew; Allsworth, Jenifer E.; Wall, L. Lewis

2013-01-01

Objective To evaluate any association between female genital cutting and vesicovaginal fistula formation during obstructed labor. Methods A comparison was made between 255 fistula patients who had undergone Type I or Type II female genital cutting and 237 patients who had not undergone such cutting. Women were operated on at the Barhirdar Hamlin Fistula Centre in Ethiopia. Data points used in the analysis included age, parity, length of labor, labor outcome (stillbirth or not), type of fistula, site, size and scarring of fistula, outcomes of surgery (fistula closed, persistent incontinence with closed fistula, urinary retention with overflow, site, size, and scarring of any rectovaginal fistula and operation outcomes, as well as specific methods employed during the operation (utilization of a graft or not, application of a pubococcygeal or similar autologous sling, vaginoplasty, catheterization of ureters, and flap reconstruction of vagina). Primary outcomes were site of genitourinary fistula and persistent incontinence despite successful fistula closure. Results The only statistically significant differences between the two groups (p = 0.05) was a slightly greater need to place ureteral catheters at the time of surgery in women who had not undergone a genital cutting operation, and slightly higher use of a pubococcygeal sling at the time of fistula repair and a slightly longer length of labor (by 0.3 of a day) in women who had undergone genital cutting. Conclusion Type I and Type II female genital cutting are not independent causative factors in the development of obstetric fistulas from obstructed labor. PMID:20177289

Bioaccumulation and biomagnification of persistent organic pollutants in Indo-Pacific humpback dolphins (Sousa chinensis) from the Pearl River Estuary, China.

PubMed

Gui, Duan; Yu, Riqing; He, Xuan; Tu, Qin; Chen, Laiguo; Wu, Yuping

2014-11-01

Indo-Pacific humpback dolphins (Sousa chinensis) are apex predators in the Pearl River Estuary waters (PRE) of China. PCBs, DDTs and other organochlorine pesticides (OCPs) (e.g., HCHs, HCB, mirex and dieldrin) were analysed in blubber samples of 45 dolphins and 10 prey fishes of S. chinensis collected from 2004 to 2013 in the PRE region to investigate the bioaccumulation and potential biomagnification of persistent organic pollutants (POPs). DDTs were the most abundant residue in the dolphins, with an average of 6,2700 ng g(-1) wet weight (ww), followed by PCBs (average: 1,790 ng g(-1) ww) and other OCPs including ∑HCHs, mirex, endrin, ∑chlordanes, HCB, dieldrin, aldrin, heptachlor, and pentachlorobenzene. The concentrations of PCBs and DDTs in male dolphins significantly increased with age and length. In contrast, female dolphins did not show obvious bioaccumulation trends with age and body length, possibly due to the lactational and parturitional transfer of these compounds. Compared with the POP residues in the prey fishes, the concentrations of PCBs, DDTs, and HCHs in the dolphin blubber increased by factors of 99, 212, and 5, respectively, whereas the residue levels of the other OCPs increased 2-185 times, indicating a potentially significant biomagnification in the top predators. The potential biomagnification factors calculated for most POPs were significantly higher than those in the cetacean species from other regions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Incidence and complications of acute kidney injury following coronary artery bypass graft: a retrospective cohort study.

PubMed

Yousefshahi, Fardin; Fakhre Yasseri, Ali Mohammad; Barkhordari, Khosro; Amini, Manouchehr; Salehi Omran, Abbas; Rezaei Hemami, Mohsen; Asadi, Mahboobeh

2015-03-01

Acute kidney injury (AKI) is a common complication of coronary artery bypass graft with several serious complications. This study aimed to find the incidence of AKI after coronary artery bypass graft and its complications based on the Acute Kidney Injury Network (AKIN) criteria. This study was done on 3470 patients who had undergone isolated coronary artery bypass graft. Acute kidney injury's incidence was based on the AKIN criteria (only based on serum creatinine irrespective of urine output). Patients' demographic data, in-hospital complications, and out-hospital mortality were collected from hospital databases and compared between the patients with and without AKI. Based on serum creatinine, the incidence of AKI was 27.7% (958 patients) on the 1st postoperative day. Nine patients (0.3%) needed hemodialysis during their hospital stay, and 31 patients (0.7%) developed persistent kidney failure until the discharge day. The number of patients undergoing hemodialysis was not significantly difference but persistent kidney failure was significantly more frequent in patients with AKI (P < .001). Those with AKI also experienced longer length of stay (P = .04) and longer length of stay in intensive care unit (P < .001), and their mortality rate was higher in hospital (P < .001) and during the 3-year follow-up period (P < .001). Although AKI is associated with great patients' morbidity and in-hospital and long-term mortality, most of AKI episodes after coronary artery bypass graft are mild with no need for hemodialysis, and they mostly improve spontaneously.

Blind Predictions of DNA and RNA Tweezers Experiments with Force and Torque

PubMed Central

Chou, Fang-Chieh; Lipfert, Jan; Das, Rhiju

2014-01-01

Single-molecule tweezers measurements of double-stranded nucleic acids (dsDNA and dsRNA) provide unprecedented opportunities to dissect how these fundamental molecules respond to forces and torques analogous to those applied by topoisomerases, viral capsids, and other biological partners. However, tweezers data are still most commonly interpreted post facto in the framework of simple analytical models. Testing falsifiable predictions of state-of-the-art nucleic acid models would be more illuminating but has not been performed. Here we describe a blind challenge in which numerical predictions of nucleic acid mechanical properties were compared to experimental data obtained recently for dsRNA under applied force and torque. The predictions were enabled by the HelixMC package, first presented in this paper. HelixMC advances crystallography-derived base-pair level models (BPLMs) to simulate kilobase-length dsDNAs and dsRNAs under external forces and torques, including their global linking numbers. These calculations recovered the experimental bending persistence length of dsRNA within the error of the simulations and accurately predicted that dsRNA's “spring-like” conformation would give a two-fold decrease of stretch modulus relative to dsDNA. Further blind predictions of helix torsional properties, however, exposed inaccuracies in current BPLM theory, including three-fold discrepancies in torsional persistence length at the high force limit and the incorrect sign of dsRNA link-extension (twist-stretch) coupling. Beyond these experiments, HelixMC predicted that ‘nucleosome-excluding’ poly(A)/poly(T) is at least two-fold stiffer than random-sequence dsDNA in bending, stretching, and torsional behaviors; Z-DNA to be at least three-fold stiffer than random-sequence dsDNA, with a near-zero link-extension coupling; and non-negligible effects from base pair step correlations. We propose that experimentally testing these predictions should be powerful next steps for understanding the flexibility of dsDNA and dsRNA in sequence contexts and under mechanical stresses relevant to their biology. PMID:25102226

Physicians' preference for controller medication in mild persistent asthma.

PubMed

Bakirtas, Arzu; Kutlu, Ali; Baccioglu, Ayse; Erkekol, Ferda Oner; Bavbek, Sevim; Kalayci, Omer

2017-10-01

Although the asthma guidelines recommend inhaled corticosteroids(ICS) or leukotriene receptor antagonists-(LTRAs) for the treatment of mild persistent asthma, factors governing the physicians' preference are unknown. We aimed to investigate the preference of physicians for the controller medication and the factors governing their choice. A self-administered questionnaire composed of 16 questions that aimed to determine the preference of the physicians for the first choice controller medication in mild persistent asthma and physician and patient related factors that may be associated with this selection was e-mailed to the members of the Turkish National Society of Allergy and Clinical Immunology and distributed to participants in the 21st congress. Of the 670 questionnaires, there were 51% participants and 336 of them were complete enough to be included in the analysis. Low dose ICS was preferred as the first choice controller medication for mild persistent asthma by 84.5% of the physicians. The reasons for physicians' preference were different for ICS and LTRA. In the logistic regression analysis, use of asthma guidelines (OR:3.5, 95%CI:1.3-9.3, p = 0.01), alignment in guidelines (OR:2.9, 95%CI:1.4-5.8, p = 0.002) and the opinion that it is a more effective (OR:2.3, 95%CI:1.1-4.8, p = 0.02) were independently associated with ICS preference. Being a pediatrician (OR:5.4, 95%CI: 2.7-10.5, p < 0.001) and the opinion that it has better patient compliance (OR:4.4, 95%CI: 1.6-12.0, p = 0.004) were independently associated with LTRA preference. Surveyed Turkish physicians, the majority of whom were specialists, preferred ICS over LTRA as controller medication in mild persistent asthma. Asthma guidelines, training background (pediatrician versus not) and perceived efficacy and patient compliance appeared to influence their preferences. Copyright © 2017. Published by Elsevier Ltd.

Volubility as a Mediator in the Associations between Conversational Language Measures and Child Temperament

PubMed Central

DeThorne, Laura Segebart; Deater-Deckard, Kirby; Mahurin-Smith, Jamie; Coletto, Mary-Kelsey; Petrill, Stephen A.

2015-01-01

Background Despite support for the use of conversational language measures, concerns remain regarding the extent to which they may be confounded with aspects of child temperament, extraversion in particular. Aims This study of 161 twins from the Western Reserve Reading Project (WRRP) examined the associations between children’s conversational language use and three key aspects of child temperament: Surgency (i.e., introversion/extraversion), Effortful Control (i.e., attention and task persistence), and Negative Affectivity (e.g., fear, anger, sadness). Child biological sex was considered as a possible moderating factor. Methods & Procedures Correlational analyses were conducted between aspects of temperament during early school-age years (i.e., 7 to 8 yrs), as measured by the Children’s Behavior Questionnaire-Short Form (CBQ; Putnam & Rothbart, 2006), and six different measures of children’s conversational language use: total number of complete and intelligible utterances (TCICU), number of total words (NTW), mean length of utterance (MLU), total number of conjunctions (TNC), number of different words (NDW), and measure D (i.e., a measure of lexical diversity). Values for NTW, TNC, and NDW were derived both on the entire sample and on the first 100 C-units. Correlations between language and temperament were compared between girls and boys using the Fisher r-to-z transformation to examine the significance of potential moderating effects. Outcomes & Results Children’s reported variability in Effortful Control did not correlate significantly with any of the child language measures. In contrast, children’s Negative Affectivity and Surgency tended to demonstrate positive, albeit modest, correlations with those conversational language measures that were derived from the sample as a whole, rather than from a standardized number of utterances. MLU, as well as measures of NDW and NTW derived from standardized sample lengths of 100 C-units, did not correlate with any measure of child temperament. TNC demonstrated an unexpected negative correlation with child Surgency when it was derived from a standardized number of C-units but not when derived from the entire sample length. Child biological sex did not moderate the significant associations between language and temperament measures. Conclusions & Implications Overall, measures that control for volubility did not correlate significantly with child temperament; however, measures that reflected volubility tended to correlate weakly with some aspects of temperament, particularly Surgency. Results provide a degree of discriminant evidence for the validity of MLU and measures of type (i.e., NDW) and token use (i.e., NTW) when derived from a standardized number of utterances. PMID:22026571

Understanding Persistent Poverty: Social Class Context in Rural Communities.

ERIC Educational Resources Information Center

Duncan, Cynthia M.

1996-01-01

Studies of persistent poverty in rural Texas, Mississippi, and Appalachia illustrate how political economies that rely on low wages and extreme control over labor generate rigid stratification. This structure of inequality determines social interaction and allocation of opportunities in rural communities, blocking upward mobility, and undermines…

DEVELOPING AN INTERNATIONAL CONSENSUS ON DDT: A BALANCE OF ENVIRONMENTAL PROTECTION AND DISEASE CONTROL.

EPA Science Inventory

The Stockholm Convention on Persistent Organic Pollutants provides a framework for international action on 12 persistent, bioaccumulative and toxic chemicals of global concern. While production and use of most of the listed chemicals will shortly be eliminated, there is widespre...

Nutrient transitions are a source of persisters in Escherichia coli biofilms.

PubMed

Amato, Stephanie M; Brynildsen, Mark P

2014-01-01

Chronic and recurrent infections have been attributed to persisters in biofilms, and despite this importance, the mechanisms of persister formation in biofilms remain unclear. The plethora of biofilm characteristics that could give rise to persisters, including slower growth, quorum signaling, oxidative stress, and nutrient heterogeneity, have complicated efforts to delineate formation pathways that generate persisters during biofilm development. Here we sought to specifically determine whether nutrient transitions, which are a common metabolic stress encountered within surface-attached communities, stimulate persister formation in biofilms and if so, to then identify the pathway. To accomplish this, we established an experimental methodology where nutrient availability to biofilm cells could be controlled exogenously, and then used that method to discover that diauxic carbon source transitions stimulated persister formation in Escherichia coli biofilms. Previously, we found that carbon source transitions stimulate persister formation in planktonic E. coli cultures, through a pathway that involved ppGpp and nucleoid-associated proteins, and therefore, tested the functionality of that pathway in biofilms. Biofilm persister formation was also found to be dependent on ppGpp and nucleoid-associated proteins, but the importance of specific proteins and enzymes between biofilm and planktonic lifestyles was significantly different. Data presented here support the increasingly appreciated role of ppGpp as a central mediator of bacterial persistence and demonstrate that nutrient transitions can be a source of persisters in biofilms.

Bacterial persistence by RNA endonucleases

PubMed Central

Maisonneuve, Etienne; Shakespeare, Lana J.; Jørgensen, Mikkel Girke; Gerdes, Kenn

2011-01-01

Bacteria form persisters, individual cells that are highly tolerant to different types of antibiotics. Persister cells are genetically identical to nontolerant kin but have entered a dormant state in which they are recalcitrant to the killing activity of the antibiotics. The molecular mechanisms underlying bacterial persistence are unknown. Here, we show that the ubiquitous Lon (Long Form Filament) protease and mRNA endonucleases (mRNases) encoded by toxin-antitoxin (TA) loci are required for persistence in Escherichia coli. Successive deletion of the 10 mRNase-encoding TA loci of E. coli progressively reduced the level of persisters, showing that persistence is a phenotype common to TA loci. In all cases tested, the antitoxins, which control the activities of the mRNases, are Lon substrates. Consistently, cells lacking lon generated a highly reduced level of persisters. Moreover, Lon overproduction dramatically increased the levels of persisters in wild-type cells but not in cells lacking the 10 mRNases. These results support a simple model according to which mRNases encoded by TA loci are activated in a small fraction of growing cells by Lon-mediated degradation of the antitoxins. Activation of the mRNases, in turn, inhibits global cellular translation, and thereby induces dormancy and persistence. Many pathogenic bacteria known to enter dormant states have a plethora of TA genes. Therefore, in the future, the discoveries described here may lead to a mechanistic understanding of the persistence phenomenon in pathogenic bacteria. PMID:21788497

Persistent Borrelia Infection in Patients with Ongoing Symptoms of Lyme Disease.

PubMed

Middelveen, Marianne J; Sapi, Eva; Burke, Jennie; Filush, Katherine R; Franco, Agustin; Fesler, Melissa C; Stricker, Raphael B

2018-04-14

Lyme disease is a tickborne illness that generates controversy among medical providers and researchers. One of the key topics of debate is the existence of persistent infection with the Lyme spirochete, Borrelia burgdorferi , in patients who have been treated with recommended doses of antibiotics yet remain symptomatic. Persistent spirochetal infection despite antibiotic therapy has recently been demonstrated in non-human primates. We present evidence of persistent Borrelia infection despite antibiotic therapy in patients with ongoing Lyme disease symptoms. In this pilot study, culture of body fluids and tissues was performed in a randomly selected group of 12 patients with persistent Lyme disease symptoms who had been treated or who were being treated with antibiotics. Cultures were also performed on a group of ten control subjects without Lyme disease. The cultures were subjected to corroborative microscopic, histopathological and molecular testing for Borrelia organisms in four independent laboratories in a blinded manner. Motile spirochetes identified histopathologically as Borrelia were detected in culture specimens, and these spirochetes were genetically identified as Borrelia burgdorferi by three distinct polymerase chain reaction (PCR)-based approaches. Spirochetes identified as Borrelia burgdorferi were cultured from the blood of seven subjects, from the genital secretions of ten subjects, and from a skin lesion of one subject. Cultures from control subjects without Lyme disease were negative for Borrelia using these methods. Using multiple corroborative detection methods, we showed that patients with persistent Lyme disease symptoms may have ongoing spirochetal infection despite antibiotic treatment, similar to findings in non-human primates. The optimal treatment for persistent Borrelia infection remains to be determined.

Understanding desisting and persisting forms of delinquency: the unique contributions of disruptive behavior disorders and interpersonal callousness.

PubMed

Byrd, Amy L; Loeber, Rolf; Pardini, Dustin A

2012-04-01

  While associations between conduct disorder (CD), oppositional defiant disorder (ODD), attention deficit hyperactivity disorder (ADHD), and interpersonal callousness (IC) symptoms and delinquency onset are well established, less is known about whether these characteristics differentiate desisting and persisting delinquency. The current study examined whether childhood and adolescent CD, ODD, ADHD, and IC symptoms uniquely distinguished boys who exhibited persisting versus desisting delinquency from adolescence into adulthood.   Participants were 503 boys (57% African American) repeatedly assessed from ages 7 to 25. Associations between childhood and adolescent CD, ODD, ADHD, and IC symptoms and desisting and persisting delinquency were examined independently and after controlling for their co-occurrence and multiple covariates.   Conduct disorder and IC symptoms in childhood and adolescence were higher among boys whose delinquency persisted into adulthood relative to those boys whose delinquency desisted across time. After controlling for the overlap between symptoms of ADHD, ODD, CD and IC, only adolescent CD and IC symptoms emerged as unique predictors of the differentiation between persisters and desisters. Moreover, adolescent CD and IC symptoms continued to contribute unique variance even after childhood levels of these characteristics were accounted for.   Boys with elevated levels of CD and IC symptoms in childhood and adolescence are at risk for exhibiting a pattern of delinquency that persists from adolescence into adulthood. Intervention efforts designed to prevent chronic delinquency should target youth with co-occurring CD and IC symptoms in childhood and adolescence. © 2011 The Authors. Journal of Child Psychology and Psychiatry © 2011 Association for Child and Adolescent Mental Health.

System for Controlling the Stirring Pin of a Friction Stir Welding Apparatus

NASA Technical Reports Server (NTRS)

Ding, R. Jeffrey (Inventor); Romine, Peter L. (Inventor); Oelgoetz, Peter A. (Inventor)

2002-01-01

A control is provided for a friction stir welding apparatus comprising a pin tool which includes a shoulder and a rotating pin extending outwardly from the shoulder of the pin tool and which, in use, is plunged into a workpiece formed contacting workpiece members to stir weld the members together. The control system controls the penetration of the pin tool into the workpiece members which are mounted on a support anvil. The control system includes a pin length controller for controlling pin length relative to the shoulder and for producing a corresponding pin length signal. A pin force sensor senses the force being exerted on the pin during welding and produces a corresponding actual pin force signal. A probe controller controls a probe extending outwardly from the pin, senses a parameter related to the distance between the probe and the supporting anvil and produces a corresponding probe signal. A workpiece standoff sensor senses the standoff distance between the workpiece and the standoff sensor and produces a corresponding standoff signal. A control unit receives the various signals, together with a weld schedule, and, based on these signals and the weld schedule, controls the pin length controller so as to control pin penetration into the workpiece.

Age of acquisition persists as the main factor in picture naming when cumulative word frequency and frequency trajectory are controlled.

PubMed

Pérez, Miguel A

2007-01-01

The aim of this study was to address the effect of objective age of acquisition (AoA) on picture-naming latencies when different measures of frequency (cumulative and adult word frequency) and frequency trajectory are taken into account. A total of 80 Spanish participants named a set of 178 pictures. Several multiple regression analyses assessed the influence of AoA, word frequency, frequency trajectory, object familiarity, name agreement, image agreement, image variability, name length, and orthographic neighbourhood density on naming times. The results revealed that AoA is the main predictor of picture-naming times. Cumulative frequency and adult word frequency (written or spoken) appeared as important factors in picture naming, but frequency trajectory and object familiarity did not. Other significant variables were image agreement, image variability, and neighbourhood density. These results (a) provide additional evidence of the predictive power of AoA in naming times independent of word-frequency and (b) suggest that image variability and neighbourhood density should also be taken into account in models of lexical production.

Expanded experimental parameter space of semiflexible polymer assemblies through programmable nanomaterials

NASA Astrophysics Data System (ADS)

Smith, David; Schuldt, Carsten; Lorenz, Jessica; Tschirner, Teresa; Moebius-Winkler, Maximilian; Kaes, Josef; Glaser, Martin; Haendler, Tina; Schnauss, Joerg

2015-03-01

Biologically evolved materials are often used as inspiration in the development of new materials as well as examinations into the underlying physical principles governing their behavior. For instance, the biopolymer constituents of the highly dynamic cellular cytoskeleton such as actin have inspired a deep understanding of soft polymer-based materials. However, the molecular toolbox provided by biological systems has been evolutionarily optimized to carry out the necessary functions of cells, and the inability modify basic properties such as biopolymer stiffness hinders a meticulous examination of parameter space. Using actin as inspiration, we circumvent these limitations using model systems assembled from programmable materials such as DNA. Nanorods with comparable, but controllable dimensions and mechanical properties as actin can be constructed from small sets of specially designed DNA strands. In entangled gels, these allow us to systematically determine the dependence of network mechanical properties on parameters such as persistence length and crosslink strength. At higher concentrations in the presence of local attractive forces, we see a transition to highly-ordered bundled and ``aster'' phases similar to those previously characterized in systems of actin or microtubules.

Nanofluidic Device with Embedded Nanopore

NASA Astrophysics Data System (ADS)

Zhang, Yuning; Reisner, Walter

2014-03-01

Nanofluidic based devices are robust methods for biomolecular sensing and single DNA manipulation. Nanopore-based DNA sensing has attractive features that make it a leading candidate as a single-molecule DNA sequencing technology. Nanochannel based extension of DNA, combined with enzymatic or denaturation-based barcoding schemes, is already a powerful approach for genome analysis. We believe that there is revolutionary potential in devices that combine nanochannels with nanpore detectors. In particular, due to the fast translocation of a DNA molecule through a standard nanopore configuration, there is an unfavorable trade-off between signal and sequence resolution. With a combined nanochannel-nanopore device, based on embedding a nanopore inside a nanochannel, we can in principle gain independent control over both DNA translocation speed and sensing signal, solving the key draw-back of the standard nanopore configuration. We demonstrate that we can detect - using fluorescent microscopy - successful translocation of DNA from the nanochannel out through the nanopore, a possible method to 'select' a given barcode for further analysis. We also show that in equilibrium DNA will not escape through an embedded sub-persistence length nanopore until a certain voltage bias is added.

Mentat/A: Medium grain parallel processing

NASA Technical Reports Server (NTRS)

Grimshaw, Andrew S.

1992-01-01

The objective of this project is to test the Algorithm to Architecture Mapping Model (ATAMM) firing rules using the Mentat run-time system and the Mentat Programming Language (MPL). A special version of Mentat, Mentat/A (Mentat/ATAMM) was constructed. This required changes to: (1) modify the run-time system to control queue length and inhibit actor firing until required data tokens are available and space is available in the input queues of all of the direct descendent actors; (2) disallow the specification of persistent object classes in the MPL; and (3) permit only decision free graphs in the MPL. We were successful in implementing the spirit of the plan, although some goals changed as we came to better understand the problem. We report on what we accomplished and the lessons we learned. The Mentat/A run-time system is discussed, and we briefly present the compiler. We present results for three applications and conclude with a summary and some observations. Appendix A contains a list of technical reports and published papers partially supported by the grant. Appendix B contains listings for the three applications.

Nature vs nurture: interplay between the genetic control of telomere length and environmental factors.

PubMed

Harari, Yaniv; Romano, Gal-Hagit; Ungar, Lior; Kupiec, Martin

2013-11-15

Telomeres are nucleoprotein structures that cap the ends of the linear eukaryotic chromosomes, thus protecting their stability and integrity. They play important roles in DNA replication and repair and are central to our understanding of aging and cancer development. In rapidly dividing cells, telomere length is maintained by the activity of telomerase. About 400 TLM (telomere length maintenance) genes have been identified in yeast, as participants of an intricate homeostasis network that keeps telomere length constant. Two papers have recently shown that despite this extremely complex control, telomere length can be manipulated by external stimuli. These results have profound implications for our understanding of cellular homeostatic systems in general and of telomere length maintenance in particular. In addition, they point to the possibility of developing aging and cancer therapies based on telomere length manipulation.

Less Is More: Results of a Statewide Analysis of the Impact of Blood Transfusion on Coronary Artery Bypass Grafting Outcomes.

PubMed

Crawford, Todd C; Magruder, J Trent; Fraser, Charles; Suarez-Pierre, Alejandro; Alejo, Diane; Bobbitt, Jennifer; Fonner, Clifford E; Canner, Joseph K; Horvath, Keith; Wehberg, Kurt; Taylor, Bradley; Kwon, Christopher; Whitman, Glenn J; Conte, John V; Salenger, Rawn

2018-01-01

Debate persists over the association between blood transfusions, especially those considered discretionary, and outcomes after cardiac operations. Using data from the Maryland Cardiac Surgery Quality Initiative, we sought to determine whether outcomes differed among coronary artery bypass grafting (CABG) patients receiving 1 U of red blood cells (RBCs) vs none. We used a statewide database to review patients who underwent isolated CABG from July 1, 2011, to June 30, 2016, across 10 Maryland cardiac surgery centers. We included patients who received 1 U or fewer of RBCs from the time of the operation through discharge. Propensity scoring, using 20 variables to control for treatment effect, was performed among patients who did and did not receive a transfusion. These two groups were matched 1:1 to assess for differences in our primary outcomes: operative death, prolonged postoperative length of stay (>14 days), and a composite postoperative respiratory complication of pneumonia or reintubation, or both. Of 10,877 patients who underwent CABG, 6,124 (56%) received no RBCs (group 1) during their operative hospitalization, and 981 (9.0%) received 1 U of RBCs (group 2), including 345 of 981 patients (35%) who received a transfusion intraoperatively. Propensity score matching generated 937 well-matched pairs. Compared with group 2, propensity-matched analysis revealed significantly greater 30-day survival in group 1 (99% vs 98%, p = 0.02) and reduced incidence of prolonged length of stay (3.7% vs 4.0%, p < 0.01). Our collaborative statewide analysis demonstrated that even 1 unit of blood was associated with significantly worse survival and longer length of stay after CABG. Multiinstitutional quality initiatives may seek to address discretionary transfusions and possess the potential to improve patient outcomes. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Antagonistic Actions of HLH/bHLH Proteins Are Involved in Grain Length and Weight in Rice

PubMed Central

Heang, Dany; Sassa, Hidenori

2012-01-01

Grain size is a major yield component in rice, and partly controlled by the sizes of the lemma and palea. Molecular mechanisms controlling the sizes of these organs largely remain unknown. In this study, we show that an antagonistic pair of basic helix-loop-helix (bHLH) proteins is involved in determining rice grain length by controlling cell length in the lemma/palea. Overexpression of an atypical bHLH, named POSITIVE REGULATOR OF GRAIN LENGTH 1 (PGL1), in lemma/palea increased grain length and weight in transgenic rice. PGL1 is an atypical non-DNA-binding bHLH and assumed to function as an inhibitor of a typical DNA-binding bHLH through heterodimerization. We identified the interaction partner of PGL1 and named it ANTAGONIST OF PGL1 (APG). PGL1 and APG interacted in vivo and localized in the nucleus. As expected, silencing of APG produced the same phenotype as overexpression of PGL1, suggesting antagonistic roles for the two genes. Transcription of two known grain-length-related genes, GS3 and SRS3, was largely unaffected in the PGL1-overexpressing and APG-silenced plants. Observation of the inner epidermal cells of lemma revealed that are caused by increased cell length. PGL1-APG represents a new grain length and weight-controlling pathway in which APG is a negative regulator whose function is inhibited by PGL1. PMID:22363621

Early Epstein-Barr Virus Genomic Diversity and Convergence toward the B95.8 Genome in Primary Infection.

PubMed

Weiss, Eric R; Lamers, Susanna L; Henderson, Jennifer L; Melnikov, Alexandre; Somasundaran, Mohan; Garber, Manuel; Selin, Liisa; Nusbaum, Chad; Luzuriaga, Katherine

2018-01-15

Over 90% of the world's population is persistently infected with Epstein-Barr virus. While EBV does not cause disease in most individuals, it is the common cause of acute infectious mononucleosis (AIM) and has been associated with several cancers and autoimmune diseases, highlighting a need for a preventive vaccine. At present, very few primary, circulating EBV genomes have been sequenced directly from infected individuals. While low levels of diversity and low viral evolution rates have been predicted for double-stranded DNA (dsDNA) viruses, recent studies have demonstrated appreciable diversity in common dsDNA pathogens (e.g., cytomegalovirus). Here, we report 40 full-length EBV genome sequences obtained from matched oral wash and B cell fractions from a cohort of 10 AIM patients. Both intra- and interpatient diversity were observed across the length of the entire viral genome. Diversity was most pronounced in viral genes required for establishing latent infection and persistence, with appreciable levels of diversity also detected in structural genes, including envelope glycoproteins. Interestingly, intrapatient diversity declined significantly over time ( P < 0.01), and this was particularly evident on comparison of viral genomes sequenced from B cell fractions in early primary infection and convalescence ( P < 0.001). B cell-associated viral genomes were observed to converge, becoming nearly identical to the B95.8 reference genome over time (Spearman rank-order correlation test; r = -0.5589, P = 0.0264). The reduction in diversity was most marked in the EBV latency genes. In summary, our data suggest independent convergence of diverse viral genome sequences toward a reference-like strain within a relatively short period following primary EBV infection. IMPORTANCE Identification of viral proteins with low variability and high immunogenicity is important for the development of a protective vaccine. Knowledge of genome diversity within circulating viral populations is a key step in this process, as is the expansion of intrahost genomic variation during infection. We report full-length EBV genomes sequenced from the blood and oral wash of 10 individuals early in primary infection and during convalescence. Our data demonstrate considerable diversity within the pool of circulating EBV strains, as well as within individual patients. Overall viral diversity decreased from early to persistent infection, particularly in latently infected B cells, which serve as the viral reservoir. Reduction in B cell-associated viral genome diversity coincided with a convergence toward a reference-like EBV genotype. Greater convergence positively correlated with time after infection, suggesting that the reference-like genome is the result of selection. Copyright © 2018 American Society for Microbiology.

The effect of the leukotriene antagonist pranlukast on pediatric acute otitis media.

PubMed

Nakamura, Yoshihisa; Hamajima, Yuki; Suzuki, Motohiko; Esaki, Shinichi; Yokota, Makoto; Oshika, Masanori; Takagi, Ippei; Yasui, Keiko; Miyamoto, Naoya; Sugiyama, Kazuko; Nakayama, Meiho; Murakami, Shingo

2016-08-01

Conventional treatment for acute otitis media mainly targets bacteria with antibiotics, neglecting to control for mediators of inflammation. Mediators of inflammation, such as leukotrienes, have been identified in patients with acute otitis media (AOM) or subsequent secretory otitis media (SOM). They can cause functional eustachian tube dysfunction or increase mucous in the middle ear, causing persistent SOM following AOM. The objective of the present study was to evaluate whether or not administration of pranlukast, a widely used leukotriene C4, D4, and E4 antagonist, together with antibiotics could inhibit the progression to SOM. Children with AOM, who were from two to 12 years old, were randomly divided into two groups as follows: a control group in which 50 patients received antibiotic-based conventional treatment according to guidelines for treating AOM proposed by the Japan Otological Society (version 2006); and a pranlukast group, in which 52 patients were administered pranlukast for up to 28 days as well as given conventional treatment. Cases were regarded as persistent SOM when a tympanogram was type B or C2 four weeks after treatment was initiated. Two patients in the pranlukast group and 3 patients in the control group were excluded because they relapsed AOM within 28 days after initial treatment. Therefore, the analysis included 50 and 47 subjects in the pranlukast and control groups, respectively. The percentage of patients diagnosed with persistent SOM (22.0%) was significantly smaller in the pranlukast group compared with the control group (44.7%) (p = 0.018, chi-squared test). The results indicate that combined treatment of AOM with antibiotics and a leukotriene antagonist to control inflammation is useful for preventing progression to persistent SOM. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Late Recovery from Stuttering: The Role of Hand Dominancy, Fine Motor and ‎Inhibition Control

PubMed Central

Mohammadi, Hiwa; Khazaie, Habibolah; Rezaei, Mansour; Joghataei, Mohammad Taghi

2016-01-01

Objective: There are controversial reports about factors that affect recovery from stuttering. In the ‎present study, the effect of hand dominancy, fine motor and inhibition control on late ‎recovery from stuttering was investigated among a group of Kurdish-Persian children who ‎stuttered in Iran.‎ Method: Twenty-two Kurdish-Persian children aged 7-14 years who stuttered were followed for 6 ‎years. Based on the evaluation of three experienced speech therapists and parental judgments, ‎these children were classified into recovered or persistent groups. Data about fine motor ‎control of hand and inhibition control were obtained, using Purdue Pegboard and Victoria ‎Strop Color Word Tests, respectively. Risk factors including sex, age, and family history of ‎stuttering, handedness, inhibitory control and fine motor control of hand were compared ‎between the groups and modeled to predict recovery from stuttering using logistic regression.‎ Results: From the 22 participants, 5 (22.7%) recovered from stuttering. The recovered and persistent ‎groups did not show significant differences in the interference effect. By dividing the scores ‎of the Purdue Pegboard tests to the right and left hand, we created a new Handedness Index ‎‎(HI). HI was significantly higher in the recovered group. The score of right hand was higher ‎than the left in the recovered group, but no difference was found between the two hands in ‎the persistent group. Among the investigated risk factors, only HI could predict the recovery ‎from or persistency of stuttering with 94% sensitivity and 84% specificity.‎ Conclusion: Handedness Index can predict the recovery from stuttering significantly among children who ‎stutter.‎ PMID:27252769

Factors affecting wound ooze in total knee replacement

PubMed Central

Butt, U; Ahmad, R; Aspros, D; Bannister, GC

2010-01-01

INTRODUCTION Wound ooze is common following total knee arthroplasty (TKA) and persistent wound infection is a risk factor for infection, and increased length and cost of hospitalisation. PATIENTS AND METHODS We undertook a prospective study to assess the effect of tourniquet time, peri-articular local anaesthesia and surgical approach on wound oozing after TKA. RESULTS The medial parapatellar approach was used in 59 patients (77%) and subvastus in 18 patients (23%). Peri-articular local anaesthesia (0.25% Bupivacaine with 1:1,000,000 adrenalin) was used in 34 patients (44%). The mean tourniquet time was 83 min (range, 38–125 min). We found a significant association between cessation of oozing and peri-articular local anaesthesia (P = 0.003), length of the tourniquet time (P = 0.03) and the subvastus approach (P = 0.01). CONCLUSIONS Peri-articular local anaesthesia, the subvastus approach and shorter tourniquet time were all associated with less wound oozing after total knee arthroplasty. PMID:20836920

Fluctuation Pressure Assisted Ejection of DNA From Bacteriophage

NASA Astrophysics Data System (ADS)

Harrison, Michael J.

2011-03-01

The role of thermal pressure fluctuations excited within tightly packaged DNA while it is ejected from protein capsid shells is discussed in a model calculation. At equilibrium before ejection we assume the DNA is folded many times into a bundle of parallel segments that forms an equilibrium conformation at minimum free energy, which presses tightly against capsid walls. Using a canonical ensemble at temperature T we calculate internal pressure fluctuations against a slowly moving or static capsid mantle for an elastic continuum model of the folded DNA bundle. It is found that fluctuating pressures on the capsid from thermal excitation of longitudinal acoustic vibrations in the bundle whose wavelengths are exceeded by the bend persistence length may have root-mean-square values that are several tens of atmospheres for typically small phage dimensions. Comparisons are given with measured data on three mutants of lambda phage with different base pair lengths and total genome ejection pressures.

Investigating plasma viscosity with fast framing photography in the ZaP-HD Flow Z-Pinch experiment

NASA Astrophysics Data System (ADS)

Weed, Jonathan Robert

The ZaP-HD Flow Z-Pinch experiment investigates the stabilizing effect of sheared axial flows while scaling toward a high-energy-density laboratory plasma (HEDLP > 100 GPa). Stabilizing flows may persist until viscous forces dissipate a sheared flow profile. Plasma viscosity is investigated by measuring scale lengths in turbulence intentionally introduced in the plasma flow. A boron nitride turbulence-tripping probe excites small scale length turbulence in the plasma, and fast framing optical cameras are used to study time-evolved turbulent structures and viscous dissipation. A Hadland Imacon 790 fast framing camera is modified for digital image capture, but features insufficient resolution to study turbulent structures. A Shimadzu HPV-X camera captures the evolution of turbulent structures with great spatial and temporal resolution, but is unable to resolve the anticipated Kolmogorov scale in ZaP-HD as predicted by a simplified pinch model.

A bead-spring chain as a one-dimensional polyelectrolyte gel.

PubMed

Manning, Gerald S

2018-05-23

The physical principles underlying expansion of a single-chain polyelectrolyte coil caused by Coulomb repulsions among its ionized groups, and the expansion of a cross-linked polyelectrolyte gel, are probably the same. In this paper, we analyze a "one-dimensional" version of a gel, namely, a linear chain of charged beads connected by Hooke's law springs. In the Debye-Hückel range of relatively weak Coulomb strength, where counterion condensation does not occur, the springs are realistically stretched on a nanolength scale by the repulsive interactions among the beads, if we use a spring constant normalized by the inverse square of the solvent Bjerrum length. The persistence length and radius of gyration counter-intuitively decrease when Coulomb strength is increased, if analyzed in the framework of an OSF-type theory; however, a buckling theory generates the increase that is consistent with bead-spring simulations.

Hydrodynamic radius fluctuations in model DNA-grafted nanoparticles

NASA Astrophysics Data System (ADS)

Vargas-Lara, Fernando; Starr, Francis W.; Douglas, Jack F.

2016-05-01

We utilize molecular dynamics simulations (MD) and the path-integration program ZENO to quantify hydrodynamic radius (Rh) fluctuations of spherical symmetric gold nanoparticles (NPs) decorated with single-stranded DNA chains (ssDNA). These results are relevant to understanding fluctuation-induced interactions among these NPs and macromolecules such as proteins. In particular, we explore the effect of varying the ssDNA-grafted NPs structural parameters, such as the chain length (L), chain persistence length (lp), NP core size (R), and the number of chains (N) attached to the nanoparticle core. We determine Rh fluctuations by calculating its standard deviation (σRh) of an ensemble of ssDNA-grafted NPs configurations generated by MD. For the parameter space explored in this manuscript, σR h shows a peak value as a function of N, the amplitude of which depends on L, lp and R, while the broadness depends on R.

A structure-based extracellular matrix expansion mechanism of fibrous tissue growth.

PubMed

Kalson, Nicholas S; Lu, Yinhui; Taylor, Susan H; Starborg, Tobias; Holmes, David F; Kadler, Karl E

2015-05-20

Embryonic growth occurs predominately by an increase in cell number; little is known about growth mechanisms later in development when fibrous tissues account for the bulk of adult vertebrate mass. We present a model for fibrous tissue growth based on 3D-electron microscopy of mouse tendon. We show that the number of collagen fibrils increases during embryonic development and then remains constant during postnatal growth. Embryonic growth was explained predominately by increases in fibril number and length. Postnatal growth arose predominately from increases in fibril length and diameter. A helical crimp structure was established in embryogenesis, and persisted postnatally. The data support a model where the shape and size of tendon is determined by the number and position of embryonic fibroblasts. The collagen fibrils that these cells synthesise provide a template for postnatal growth by structure-based matrix expansion. The model has important implications for growth of other fibrous tissues and fibrosis.

Factors affecting wound ooze in total knee replacement.

PubMed

Butt, U; Ahmad, R; Aspros, D; Bannister, G C

2011-01-01

Wound ooze is common following total knee arthroplasty (TKA) and persistent wound infection is a risk factor for infection, and increased length and cost of hospitalisation. We undertook a prospective study to assess the effect of tourniquet time, peri-articular local anaesthesia and surgical approach on wound oozing after TKA. The medial parapatellar approach was used in 59 patients (77%) and subvastus in 18 patients (23%). Peri-articular local anaesthesia (0.25% Bupivacaine with 1:1,000,000 adrenalin) was used in 34 patients (44%). The mean tourniquet time was 83 min (range, 38-125 min). We found a significant association between cessation of oozing and peri-articular local anaesthesia (P = 0.003), length of the tourniquet time (P = 0.03) and the subvastus approach (P = 0.01). Peri-articular local anaesthesia, the subvastus approach and shorter tourniquet time were all associated with less wound oozing after total knee arthroplasty.

HIV reservoirs as obstacles and opportunities for an HIV cure.

PubMed

Chun, Tae-Wook; Moir, Susan; Fauci, Anthony S

2015-06-01

The persistence of HIV reservoirs remains a formidable obstacle to achieving sustained virologic remission in HIV-infected individuals after antiretroviral therapy (ART) is discontinued, even if plasma viremia has been successfully suppressed for prolonged periods of time. Numerous approaches aimed at eradicating the virus, as well as maintaining its prolonged suppression in the absence of ART, have had little success. A better understanding of the pathophysiologic nature of HIV reservoirs and the impact of various interventions on their persistence is essential for the development of successful therapeutic strategies against HIV or the long-term control of infection. Here, we discuss the persistent HIV reservoir as a barrier to cure as well as the current therapeutic strategies aimed at eliminating or controlling the virus in the absence of ART.

Temporal Persistence of Attitudes Induced Through Required Training

ERIC Educational Resources Information Center

Tansik, David A.; Driskill, John D.

1977-01-01

A posttest-only control group design procedure was used with a semantic differential questionnaire to examine the persistence of changes in racial attitudes induced via a required training course for supervisors at a large military installation. There was an immediate, small, positive change which decayed, and a short "sleeper effect". (Author)

The Academic Library Impact on Student Persistence

ERIC Educational Resources Information Center

Emmons, Mark; Wilkinson, Frances C.

2011-01-01

What impact does the academic library have on student persistence? This study explores the relationship between traditional library input and output measures of staff, collections, use, and services with fall-to-fall retention and six-year graduation rates at Association of Research Libraries member libraries. When controlling for race/ethnicity…

Worry and cognitive control predict course trajectories of anxiety in older adults with late-life depression.

PubMed

Spinhoven, P; van der Veen, D C; Voshaar, R C Oude; Comijs, H C

2017-07-01

Many older adults with depressive disorder manifest anxious distress. This longitudinal study examines the predictive value of worry as a maladaptive cognitive emotion regulation strategy, and resources necessary for successful emotion regulation (i.e., cognitive control and resting heart rate variability [HRV]) for the course of anxiety symptoms in depressed older adults. Moreover, it examines whether these emotion regulation variables moderate the impact of negative life events on severity of anxiety symptoms. Data of 378 depressed older adults (CIDI) between 60 and 93 years (of whom 144 [41%] had a comorbid anxiety disorder) from the Netherlands Study of Depression in Older Adults (NESDO) were used. Latent Growth Mixture Modeling was used to identify different course trajectories of six-months BAI scores. Univariable and multivariable longitudinal associations of worry, cognitive control and HRV with symptom course trajectories were assessed. We identified a course trajectory with low and improving symptoms (57.9%), a course trajectory with moderate and persistent symptoms (33.5%), and a course trajectory with severe and persistent anxiety symptoms (8.6%). Higher levels of worry and lower levels of cognitive control predicted persistent and severe levels of anxiety symptoms independent of presence of anxiety disorder. However, worry, cognitive control and HRV did not moderate the impact of negative life events on anxiety severity. Worry may be an important and malleable risk factor for persistence of anxiety symptoms in depressed older adults. Given the high prevalence of anxious depression in older adults, modifying worry may constitute a viable venue for alleviating anxiety levels. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Long leukocyte telomere length in prostate cancer patients at diagnosis is associated with poor metastasis-free and cancer-specific survival.

PubMed

Svenson, Ulrika; Roos, Göran; Wikström, Pernilla

2017-02-01

Previous studies have suggested that leukocyte telomere length is associated with risk of developing prostate cancer. Investigations of leukocyte telomere length as a prognostic factor in prostate cancer are, however, lacking. In this study, leukocyte telomere length was investigated both as a risk marker, comparing control subjects and patient risk groups (based on serum levels of prostate-specific antigen, tumor differentiation, and tumor stage), and as a prognostic marker for metastasis-free and cancer-specific survival. Relative telomere length was measured by a well-established quantitative polymerase chain reaction method in 415 consecutively sampled individuals. Statistical evaluation included 162 control subjects without cancer development during follow-up and 110 untreated patients with newly diagnosed localized prostate cancer at the time of blood draw. Leukocyte telomere length did not differ significantly between control subjects and patients, or between patient risk groups. Interestingly, however, and in line with our previous results in breast and kidney cancer patients, relative telomere length at diagnosis was an independent prognostic factor. Patients with long leukocyte telomeres (⩾median) had a significantly worse prostate cancer-specific and metastasis-free survival compared to patients with short telomere length. In contrast, for patients who died of other causes than prostate cancer, long relative telomere length was not coupled to shorter survival time. To our knowledge, these results are novel and give further strength to our hypothesis that leukocyte telomere length might be used as a prognostic marker in malignancy.

Androgen receptor repeat length polymorphism associated with male-to-female transsexualism.

PubMed

Hare, Lauren; Bernard, Pascal; Sánchez, Francisco J; Baird, Paul N; Vilain, Eric; Kennedy, Trudy; Harley, Vincent R

2009-01-01

There is a likely genetic component to transsexualism, and genes involved in sex steroidogenesis are good candidates. We explored the specific hypothesis that male-to-female transsexualism is associated with gene variants responsible for undermasculinization and/or feminization. Specifically, we assessed the role of disease-associated repeat length polymorphisms in the androgen receptor (AR), estrogen receptor beta (ERbeta), and aromatase (CYP19) genes. Subject-control analysis included 112 male-to-female transsexuals and 258 non-transsexual males. Associations and interactions were investigated between CAG repeat length in the AR gene, CA repeat length in the ERbeta gene, and TTTA repeat length in the CYP19 gene and male-to-female transsexualism. A significant association was identified between transsexualism and the AR allele, with transsexuals having longer AR repeat lengths than non-transsexual male control subjects (p=.04). No associations for transsexualism were evident in repeat lengths for CYP19 or ERbeta genes. Individuals were then classified as short or long for each gene polymorphism on the basis of control median polymorphism lengths in order to further elucidate possible combined effects. No interaction associations between the three genes and transsexualism were identified. This study provides evidence that male gender identity might be partly mediated through the androgen receptor.

Androgen Receptor Repeat Length Polymorphism Associated with Male-to-Female Transsexualism

PubMed Central

Hare, Lauren; Bernard, Pascal; Sánchez, Francisco J.; Baird, Paul N.; Vilain, Eric; Kennedy, Trudy; Harley, Vincent R.

2012-01-01

Background There is a likely genetic component to transsexualism, and genes involved in sex steroidogenesis are good candidates. We explored the specific hypothesis that male-to-female transsexualism is associated with gene variants responsible for undermasculinization and/or feminization. Specifically, we assessed the role of disease-associated repeat length polymorphisms in the androgen receptor (AR), estrogen receptor β (ERβ), and aromatase (CYP19) genes. Methods Subject-control analysis included 112 male-to-female transsexuals and 258 non-transsexual males. Associations and interactions were investigated between CAG repeat length in the AR gene, CA repeat length in the ERβ gene, and TTTA repeat length in the CYP19 gene and male-to-female transsexualism. Results A significant association was identified between transsexualism and the AR allele, with transsexuals having longer AR repeat lengths than non-transsexual male control subjects (p = .04). No associations for transsexualism were evident in repeat lengths for CYP19 or ERβ genes. Individuals were then classified as short or long for each gene polymorphism on the basis of control median polymorphism lengths in order to further elucidate possible combined effects. No interaction associations between the three genes and transsexualism were identified. Conclusions This study provides evidence that male gender identity might be partly mediated through the androgen receptor. PMID:18962445

Dynamic and functional balance tasks in subjects with persistent whiplash: a pilot trial.

PubMed

Stokell, Raina; Yu, Annie; Williams, Katrina; Treleaven, Julia

2011-08-01

Disturbances in static balance have been demonstrated in subjects with persistent whiplash. Some also report loss of balance and falls. These disturbances may contribute to difficulties in dynamic tasks. The aim of this study was to determine whether subjects with whiplash had deficits in dynamic and functional balance tasks when compared to a healthy control group. Twenty subjects with persistent pain following a whiplash injury and twenty healthy controls were assessed in single leg stance with eyes open and closed, the step test, Fukuda stepping test, tandem walk on a firm and soft surface, Singleton test with eyes open and closed, a stair walking test and the timed 10 m walk with and without head movement. Subjects with whiplash demonstrated significant deficits (p < 0.01) in single leg stance with eyes closed, the step test, tandem walk on a firm and soft surface, stair walking and the timed 10 m walk with and without head movement when compared to the control subjects. Specific assessment and rehabilitation directed towards improving these deficits may need to be considered in the management of patients with persistent whiplash if these results are confirmed in a larger cohort. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Persistent high-risk human papillomavirus (HPV) infections as surrogate endpoints of progressive cervical disease. Potential new endpoint for efficacy studies with new-generation (non-HPV 16/18) prophylactic HPV vaccines.

PubMed

Syrjänen, K

2011-01-01

Recent data indicate that persistent HR-HPV infections represent a significantly increased risk of developing incident high-grade CIN and cervical cancer. Accordingly, 6-month (6M+) or 12-month (12M+) type-specific persistence of HR-HPV have been proposed as powerful surrogates of progressive disease. Because of substantial practical impact in future HPV vaccine trials using non-HPV 16/18 vaccines, studies on HR-HPV persistence as a surrogate endpoint of progressive CIN have been subject to a comprehensive meta-analyses recently. The present communication was solicited to bring this important and timely topic to the awareness of the readers, in a format consisting of a review of the recent literature, supplemented with the author's own experience from different studies. Based on a large number of relevant studies, there remains little doubt that persistence of HR-HPV for 6+ or 12+ months is associated with a significantly increased risk of developing incident high-grade CIN. However, some data also disclosed several important issues that need to be carefully considered and/or adequately resolved before adopting 6M+ or 12M+ HR-HPV persistence as a surrogate of progressive disease. These include i) definitions of HPV persistence, ii) HPV detection techniques and iii) testing intervals and iv) length of follow-up, as well as v) diagnosis of the surrogate endpoints, and vi) other study characteristics, including vii) the type of reference category used in calculating the risk estimates. All these issues are critically discussed in the present communication. Of major impact seems to be the reference category used to calculate these risk estimates, as evident from the NIS-LAMS cohort. Taken together, it is suggested that in all future studies using the 6M+ or 12M+ HR-HPV persistence as a surrogate endpoint of progressive disease, a "gold standard" should be used in calculating the risk estimates. In addition to deciding, 1) whether to use 6M+ or 12M+ persistence criteria, and 2) cytological, histological or combined surrogate endpoints (SIL, CIN1, CIN2, CIN/SIL), one should 3) use exclusively the HPV negative reference group in calculating the risk estimates for viral persistence endpoints. This is supported by the data from the recent meta-analysis as well as from the author's combined NIS-LAMS cohort, both implicating that the most consistent association to progressive disease is obtained when women with persistent HR-HPV are compared with HPV-negative women. It is the conviction of this author that the two other reference categories (HPV transient and HPV mixed outcome) are far too heterogeneous and subject to potential misclassifications to give consistent and reproducible risk estimates for HR-HPV persistence as a surrogate endpoint of progressive CIN.

The relationships between chronological age, length of experience, and job performance ratings of air route traffic control specialists.

DOT National Transportation Integrated Search

1967-06-01

The survey-type study of several hundred journeymen radar control specialists of four Air Route Traffic Control Centers was conducted in order to determine the extent to which job performance might be associative with chronological age and length of ...

Hydrologic modeling to screen potential environmental management methods for malaria vector control in Niger

NASA Astrophysics Data System (ADS)

Gianotti, Rebecca L.; Bomblies, Arne; Eltahir, Elfatih A. B.

2009-08-01

This paper describes the first use of Hydrology-Entomology and Malaria Transmission Simulator (HYDREMATS), a physically based distributed hydrology model, to investigate environmental management methods for malaria vector control in the Sahelian village of Banizoumbou, Niger. The investigation showed that leveling of topographic depressions where temporary breeding habitats form during the rainy season, by altering pool basin microtopography, could reduce the pool persistence time to less than the time needed for establishment of mosquito breeding, approximately 7 days. Undertaking soil surface plowing can also reduce pool persistence time by increasing the infiltration rate through an existing pool basin. Reduction of the pool persistence time to less than the rainfall interstorm period increases the frequency of pool drying events, removing habitat for subadult mosquitoes. Both management approaches could potentially be considered within a given context. This investigation demonstrates that management methods that modify the hydrologic environment have significant potential to contribute to malaria vector control in water-limited, Sahelian Africa.

An educational intervention to improve cost-effective care among medicine housestaff: a randomized controlled trial.

PubMed

Sommers, Benjamin D; Desai, Nihar; Fiskio, Julie; Licurse, Adam; Thorndike, Mary; Katz, Joel T; Bates, David W

2012-06-01

High medical costs create significant burdens. Research indicates that doctors have little awareness of costs. This study tested whether a brief educational intervention could increase residents' awareness of cost-effectiveness and reduce costs without negatively affecting patient outcomes. The authors conducted a clustered randomized controlled trial of 33 teams (96 residents) at an internal medicine residency program (2009-2010). The intervention was a 45-minute teaching session; residents reviewed the hospital bill of a patient for whom they had cared and discussed reducing unnecessary costs. Primary outcomes were laboratory, pharmacy, radiology, and total hospital costs per admission. Secondary measures were length of stay (LOS), intensive care unit (ICU) admission, 30-day readmission, and 30-day mortality. Multivariate adjustment controlled for patient demographics and health. A follow-up survey assessed resident attitudes three months later. Among 1,194 patients, there were no significant cost differences between intervention and control groups. In the intervention group, 30-day readmission was higher (adjusted odds ratio 1.51, P = .010). There was no effect on LOS or the composite outcome of readmission, mortality, and ICU transfer. In a subgroup analysis of 835 patients newly admitted during the study, the intervention group incurred $163 lower adjusted lab costs per admission (P = .046). The follow-up survey indicated persistent differences in residents' exposure to concepts of cost-effectiveness (P = .041). A brief intervention featuring a discussion of hospital bills can fill a gap in resident education and reduce laboratory costs for a subset of patients, but may increase readmission risk.

Early accelerated senescence of circulating endothelial progenitor cells in premature coronary artery disease patients in a developing country - a case control study.

PubMed

Vemparala, Kranthi; Roy, Ambuj; Bahl, Vinay Kumar; Prabhakaran, Dorairaj; Nath, Neera; Sinha, Subrata; Nandi, Pradipta; Pandey, Ravindra Mohan; Reddy, Kolli Srinath; Manhapra, Ajay; Lakshmy, Ramakrishnan

2013-11-19

The decreased number and senescence of circulating endothelial progenitor cells (EPCs) are considered markers of vascular senescence associated with aging, atherosclerosis, and coronary artery disease (CAD) in elderly. In this study, we explore the role of vascular senescence in premature CAD (PCAD) in a developing country by comparing the numerical status and senescence of circulating EPCs in PCAD patients to controls. EPCs were measured by flow cytometry in 57 patients with angiographically documented CAD, and 57 controls without evidence of CAD, recruited from random patients ≤ 50 years of age at All India Institute of Medical Sciences. EPC senescence as determined by telomere length (EPC-TL) and telomerase activity (EPC-TA) was studied by real time polymerase chain reaction (q PCR) and PCR- ELISA respectively. The number of EPCs (0.18% Vs. 0.039% of total WBCs, p < 0.0001), and EPC-TL (3.83 Vs. 5.10 kb/genome, p = 0.009) were markedly lower in PCAD patients compared to controls. These differences persisted after adjustment for age, sex, BMI, smoking and medications. EPC-TA was reduced in PCAD patients, but was statistically significant only after adjustment for confounding factors (1.81 Vs. 2.20 IU/cell, unadjusted p = 0.057, adjusted p = 0.044). We observed an association between increased vascular cell senescence with PCAD in a sample of young patients from India. This suggests that early accelerated vascular cell senescence may play an important mechanistic role in CAD epidemic in developing countries like India where PCAD burden is markedly higher compared to developed countries.

Reduced pleural drainage, length of stay, and readmissions using a modified Fontan management protocol.

PubMed

Pike, Nancy A; Okuhara, Carol A; Toyama, Joy; Gross, Barbara P; Wells, Winfield J; Starnes, Vaughn A

2015-09-01

Persistent pleural effusions after the Fontan procedure contribute to prolonged hospitalization and increased costs. We report our experience using a modified Wisconsin Fontan protocol to reduce chest tube drainage and hospital length of stay (LOS). Single institutional retrospective chart review of 120 consecutive patients (60 before and 60 after initiation of our protocol) undergoing an extracardiac Fontan procedure from January 2004 to February 2007. Protocol influence was assessed by comparing group differences on duration of pleural drainage, requirement for nothing by mouth/total parenteral nutrition, hospital LOS, readmission for pleural effusion, and total hospital costs. Groups were similar in demographic characteristics, single ventricle morphology, preoperative hemodynamic parameters, and operative and immediate postoperative management. Median duration of pleural drainage and hospital LOS was reduced in the post- versus preprotocol groups: 4 days (interquartile range [IQR], 4-5 days) pre versus 6 days (IQR, 5-10 days) (P < .0001) and 6 days (IQR, 5-9 days) versus 8 days (IQR, 6-13 days) (P = .005), respectively. Pleural drainage lasting >1 week was also less common postprotocol: 23 (38%) before versus 7 (12%) after (P = .001). Fewer postprotocol patients required nothing by mouth/total parenteral nutrition to control effusions: 5 pre versus 0 post (P = .06), and fewer readmissions for effusions (14 before vs 7 after [P = .1]). An average total cost savings of 22% and readmissions savings of 29% resulted in nearly $500,000 in institutional savings over the study period. A modified Fontan protocol resulted in reduced time to chest tube removal, hospital LOS, and chest tube drainage lasting >1 week. There was a strong trend toward avoiding nothing by mouth/total parenteral nutrition to control pleural effusion and lower hospital costs. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Incidence, size and spatial structure of clones in second-growth stands of coast redwood, Sequoia sempervirens (Cupressaceae).

PubMed

Douhovnikoff, Vladimir; Cheng, Adelaide M; Dodd, Richard S

2004-07-01

The ecology and evolutionary potential of coast redwood (Sequoia sempervirens) is significantly influenced by the important role clonal spread plays in its reproduction and site persistence. In nine second-growth stands, amplified fragment length polymorphisms (AFLPs) were used to identify redwood clonal architecture. Clones (multistem genets) dominated sites by representing an average of 70% of stems measured, ranging in size from two to 20 stems. As a result, a relatively small number of genets can monopolize a disproportionate amount of site resources, are more likely to persist over time, and have greater on-site genetic representation. Clones were not limited to fairy-ring structures, but consisted of a wide range of shapes including concentric rings, ring chains, disjunct, and linear structures. Between-ramet distances of up to 40 m were measured, indicating that clonal reproduction is not limited to basal stump resprouting. Clonal structure in second-growth stands was similar to earlier reports from old growth, emphasizing the importance of site persistence and long-term, gradual site development. Smaller ramet numbers per genet in old growth is probably due to local within-genet self thinning. Management and conservation of redwoods will benefit from a better understanding of the dynamics and structure of clonal spread in these forests.

Bearded dragons (Pogona vitticeps) asymptomatically infected with Devriesea agamarum are a source of persistent clinical infection in captive colonies of dab lizards (Uromastyx sp.).

PubMed

Devloo, R; Martel, A; Hellebuyck, T; Vranckx, K; Haesebrouck, F; Pasmans, F

2011-06-02

Devriesea agamarum causes dermatitis and septicaemia in a variety of lizards, notably those belonging to the genus Uromastyx, whereas other species such as bearded dragons (Pogona vitticeps) seem to be asymptomatic carriers. Using amplified fragment length polymorphism (AFLP), the relatedness between 69 D. agamarum isolates was examined. The isolates derived from 44 diseased lizards, of which 31 belonged to the genus Uromastyx, and from 25 healthy lizards, of which 21 were bearded dragons. Eight AFLP genotypes were obtained, four of which comprised 93% of the isolates. These four genotypes were each present in 2, 2, 8 and 13 different captive colonies. Up to three genotypes were isolated from a single infected colony simultaneously. On two occasions, the same genotype was found in healthy bearded dragons and diseased Uromastyx lizards from the same colony, confirming the role of the former as an asymptomatic source of infection for the latter. Two genotypes, comprising 12 isolates, were exclusively associated with diseased Uromastyx lizards, suggesting strain dependent host adaptation. Finally, D. agamarum was shown to be able to persist for at least seven years in a lizard colony, persistently causing severe disease in several lizard species. Copyright © 2011 Elsevier B.V. All rights reserved.

Autosplenectomy of sickle cell disease in zaria, Nigeria: an ultrasonographic assessment.

PubMed

Babadoko, A A; Ibinaye, P O; Hassan, A; Yusuf, R; Ijei, I P; Aiyekomogbon, J; Aminu, S M; Hamidu, A U

2012-03-01

During infancy and early childhood, the spleen commonly enlarges in patients with sickle cell anemia (SCA), and it thereafter undergoes progressive atrophy due to repeated episodes of vaso-occlusion and infarction, leading to autosplenectomy in adult life. However, this may not always be the case as some studies have reported splenomegaly persisting into adult life. This study aims to determine and review the prevalence of autosplenectomy by abdominal ultrasonography in sickle cell anemic patients in Zaria, Nigeria. An ex-post-facto cross study of 74 subjects was carried out between May to July in 2010. Hematological parameters were determined by an analyzer while B mode Ultrasonography was used to determine the craniocaudal length of the spleen, if visualized. The mean age of the sickle cell subjects was 23.2 ±5.3 years, while that of the controls was 22.7±12.4 years. Of the 74 sickle cell subjects, 55.4% were females; while of the 20 controls, 50% were females. Forty one subjects (55.4%) had autosplenectomy and a significant difference existed in the mean splenic size compared with the control (p<0.0001). Only 3 (4.05%) subjects had splenomegaly, while 23 (31%) had a shrunken spleen. Anatomical autosplenectomy is not an uncommon finding in SCA patients. This may be related to inadequate clinical care due to the lack of good health education, ignorance, poverty, and poor standard of care, as well as the lack of newer therapeutic agents.