369 research outputs found

    Daily Habits in Parkinson's Disease: Validation of the Daily Habit Scale

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    Objective: The objective of the study was to validate a new scale for assessing habitual behavior—the Daily Habit Scale in patients with Parkinson's disease. Background: Parkinson's disease patients are impaired in habit learning and skill acquisition. Despite repeated practice, they have difficulty developing habitual responses. Methods: One hundred seventy-nine patients (Median (Mdn) = 69 [64–76], 65 females) participated in the study. Corrected item-to-total correlations were calculated to assess the item-convergent and item discriminant validity. Confirmatory factor analysis and assessment of internal consistency were also carried out. Concurrent validity in respect to measures of anxiety and depression, apathy, impulsivity, personality, multidimensional health locus of control, and health-related quality of life was also calculated. To determine the test–retest reliability of the scale, 30 patients (Mdn = 69 [66–73], 9 females) completed a second copy of the scale 6 months after the first. Results: Twenty-nine items (76%) and 9 items (24%) of the 38-item scale, respectively, showed a very good and good convergent validity. All the items discriminated between their own factor and the other factors. The comparative fit index of 0.932 indicated an acceptable model fit of the data, whereas the root mean square error of approximation of 0.06 moderate model fit. The scale had a good internal consistency (Cronbach α = 0.792), and a moderate test–retest reliability (0.57). Females had higher scores on two factors compared to men (Factor 3: household activities and Factor 8: sleep-related activities). Conclusions: The Daily Habit Scale is a reliable and valid tool to measure daily habits in Parkinson's disease

    Link Slab Details and Materials

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    This report contains the findings of a synthesis study on the use of link slabs to eliminate intermediate joints in bridges of Indiana. The study was conducted under the sponsorship of the Joint Transportation Research Program. The motivation for the study was to investigate this promising technique to mitigate the damage associated with expansion joints that has long been recognized as a persistent and costly issue negatively impacting the bridge service life. The report summarizes the background information and motivation for the study. It also provides a description of the report organization. The results of an extensive literature review of DOTs’ experience related to the use of this system and main research findings are presented as well as construction practice and examples of application. The results of the analysis of a bridge in Indiana where the link slab system has been implemented are presented. The bridge connecting the State Road 68 over the Interstate 64 was selected as a representative bridge based on the analysis of the inspection. A parametric study on the effects of various parameters was conducted to evaluate the effect of support conditions and debonded length on the stress distribution and potential crack initiation in link slabs. Each variable was investigated separately to isolate its effect. Two bridge structures were investigated in this study. The first structure (Case 1) represents a bridge structure rehabilitated using link slabs. A second bridge structure (Case 2) with the same geometrical and material properties, but with a continuous and fully bonded deck, was also included in the parametric study for comparison purposes. This structure simulated new bridge construction

    Formal inverse integrating factors and the nilpotent center problem

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    We are interested in deepening knowledge of methods based on formal power series applied to the nilpotent center problem of planar local analytic monodromic vector fields X. As formal integrability is not enough to characterize such a centers we use a more general object, namely, formal inverse integrating factors V of X. Although by the existence of V is not possible to describe all nilpotent centers strata, we simplify, improve and also extend previous results on the relationship between these concepts. We use in the performed analysis the so-called Andreev number n N with n > 2 associated to X which is invariant under orbital conjugacy of X. Besides the leading terms in the (1,n)-quasihomogeneous expansions that V can have we also prove the following: (i) If n is even and there exists V then X has a center; (iii) If the existence of V characterizes all the centers; (iii) If there is a V with minimum ``vanishing multiplicity' at the singularity then, generically, X has a center.The author is partially supported by a MINECO grant number MTM2014-53703-P and by a CIRIT grant number 2014 SGR 1204

    Antibacterial efficacy of lytic bacteriophages against antibiotic-resistant Klebsiella species

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    Bacterial resistance to antibiotics is a leading and highly prevalent problem in the treatment of infectious diseases. Bacteriophages (phages) appear to be effective and safe alternatives for the treatment of resistant infections because of their specificity for bacterial species and lack of infectivity in eukaryotic cells. The present study aimed to isolate bacteriophages against Klebsiella spp. and evaluate their efficacy against antibiotic-resistant species. Seventy-two antibiotic-resistant Klebsiella spp. were isolated from samples of patients who referred to the Ghaem Hospital (Mashhad, Iran). Lytic bacteriophages against Klebsiella spp. were isolated from wastewater of the septic tank of the same hospital. Bactericidal activity of phages against resistant Klebsiella spp. was tested in both liquid (tube method; after 1 and 24 h of incubation) and solid (double-layer agar plate method; after 24 h of incubation) phases. In each method, three different concentrations of bacteriophages (low: <10 4 PFU/mL, medium: 10 4 -10 7 PFU/mL, and high: >10 7 PFU/mL) were used. Bacteriophages showed promising bactericidal activity at all assessed concentrations, regardless of the test method and duration of incubation. Overall, bactericidal effects were augmented at higher concentrations. In the tube method, higher activity was observed after 24 h of incubation compared to the 1-h incubation. The bactericidal effects were also higher in the tube method compared to the double-layer agar plate method after 24 h of incubation. The findings of the present study suggest that bacteriophages possess effective bactericidal activity against resistant Klebsiella spp. These bactericidal activities are influenced by phage concentration, duration of incubation, and test method. KEYWORDS: bacteriophage, Klebsiella, antibiotic resistance Karamoddini et al.: Bacteriophages Against Resistant Klebsiella Species TheScientificWorldJOURNAL (2011) 11, 1332-1340 1333 INTRODUCTION Bacteriophages (also called phages) are reported to be the most abundant organisms on earth Based on the replication type, phages are classified as either lytic or lysogenic. A lytic phage replicates in the bacterial host and destroys its host in a process, but a lysogenic phage inserts itself into the genome of its bacterial host and establishes a stable position in the infected bacterium After discovery, phages were the target of multiple research for the treatment of bacterial diseases, such as dysentery In spite of the great progress that has been made in the field of antimicrobial therapy, the appearance and spread of drug-resistant bacteria has caused a serious challenge in recent decades. As an example, the prevalence of resistant nosocomial infections is increasing at an alarming rate and their elimination is very difficult. This could be secondary to the wide use of antibiotics, as well as application of therapeutic measures that weaken the immune system and make subjects more susceptible to nosocomial infections. Phage therapy could be an effective alternative approach for the control of these infections, as several studies have shown their efficacy against both Gram-positive and Gram-negative bacteria The purpose of the present study was to isolate and enrich lytic bacteriophages against Klebsiella spp. and evaluate their antibacterial efficacy against antibiotic-resistant species. The impact of phage concentration, incubation duration, and method of culture (tube vs. plate) on the bactericidal effect was also investigated. MATERIALS AND METHODS Isolation of Klebsiella spp. Different samples, mainly from urine, vaginal smears, blood, wounds and their secretions, and burn lesions, were collected from patients referring to the Ghaem Hospital (Mashhad, Iran) during a course of about 1.5 years between November 2001 and March 2003. Samples were cultured on general (simple blood agar; supporting the growth of most microorganisms) as well as specific (MacConkey agar, desoxycholate agar, or eosin methylene blue agar; supporting the growth of Gram-negative bacteria) culture media. Culture media plates were incubated at 37°C for 24 h. To confirm the isolation of Klebsiella spp., Gram staining and multiple biochemical tests were performed, including glucose and lactose fermentation (Kligler iron agar medium), citrate utilization (Simmons citrate agar medium), urea (urea agar medium), hydrogen sulfide production, indole formation and motility (sulfide-indole-motility [SIM] agar medium; Kligler iron agar medium), and malonate utilization (malonate agar medium) tests. Determination of Klebsiella spp. Sensitivity to Antibiotics Mueller-Hinton agar medium was used to culture the appropriate bacteria. Colonies were first suspended in 5 mL of tripticase soy broth and kept at 37°C for several hours until the turbidity of the suspension changed, similar to that of barium sulfate solution in the 0.5 McFarland standard tube (the standard tube was shaken vigorously before usage). A sterile swab was stirred in the above suspension and the sample was cultured on Mueller-Hinton agar medium. Antibiotic disks were placed at a 15-mm distance from the Karamoddini et al.: Bacteriophages Against Resistant Klebsiella Species TheScientificWorldJOURNAL (2011) 11, 1332-1340 1334 edge of the plate. Different disks were 24 mm from the center of each nearest disk. Following a 24-h incubation at 37°C, the growth inhibition zone was measured and compared with tables provided by the National Committee for Clinical Laboratory Standards (NCCLS). The results of sensitivity were reported as sensitive, resistant, or intermediate. Antibiotics that were evaluated included ampicillin, amoxicillin, amikacin, cephalexin, chloramphenicol, nitrofurantoin (for urine samples), gentamicin, kanamycin, nalidixic acid (for urine samples), rifampin, streptomycin, tetracycline, doxycycline, tobramycin, and sulfamethoxazole. Smooth agar containing glycerin was used to keep resistant Klebsiella colonies at -20°C as follows: four to five colonies were transferred to 20 mL of triple soy broth. After 4 h of incubation at 37°C, the tube containing tryptone soy broth was centrifuged at 2500 rpm. Then, 0.5 mL of the above-cultured bacteria was transferred to a Pyrex® test tube containing 3 mL of 3% Mueller-Hinton. Test tubes were incubated at 37°C for 4-6 h in order to accelerate bacterial growth. Following that, 0.5 mL of sterile glycerin was added to test tubes and tubes were transferred to -20°C. Isolation, Enrichment, Titration, and Bacteriophages Bacteriophages utilized in this study were isolated from wastewater of the septic tank in Ghaem Hospital that had been filter sterilized. To the aforementioned wastewater (45 mL), concentrated nutrient broth medium (5 mL) and 4-h antibiotic-resistant Klebsiella culture (5 mL) were added. Also added was 1% (v/w) MgSo 4 to provide optimum attachment of bacteriophage to bacteria. The mixture was then gently shaken and kept at 37°C for 24 h. Afterwards, chloroform was added (3 mL) and the mixture was shaken for 15 min. After being kept at room temperature for 2 h, the mixture was centrifuged (30 min, 3500 rpm) and the supernatant carefully isolated. For phage enrichment, the obtained supernatant was mixed with nutrient broth (10 mL) and 4-h Klebsiella culture (2 mL). The mixture was then processed as described above. Phage suspension was maintained in the nutrient broth at 4°C in a dark place using sterile and sealed glass containers. For the titration of phages, enriched samples were diluted by 10X in tubes containing 9 mL of tryptone broth. Then, 100 µL of each diluted sample was transferred to tubes containing 3 mL of soft agar. Afterwards, 4-h Klebsiella culture (1 mL) was added to each tube. Tubes were then shaken and their contents rapidly transferred to plates containing tryptone agar medium. The plates were incubated at 37°C for 24 h. Plates containing 30-300 plaques were used to calculate the number of phages in the primary solution using the following formula: Number of phages = Number of plaques × dilution titer × volume of media Evaluation of Antibacterial Activity The antibacterial effects of phages against antibiotic-resistant Klebsiella spp. were tested by the tube method and the double-layer agar plate method at two time points: after 1 h (for the tube method) and 24 h (for both tube and plate methods) of incubation at 37°C. In each method, three different concentrations of phages were tested: low (<10 4 PFU/mL), medium (10 4 -10 7 PFU/mL), and high (>10 7 PFU/ mL). According to the intensity of growth inhibition, the results were reported as +++ (75-100% reduction of bacteria compared to control), ++ (50-75% reduction of bacteria compared to control), + (25-50% reduction of bacteria compared to control), and -(<25% reduction of bacteria compared to control). Statistical Analysis All comparisons were performed using Fisher's exact test. A two-sided p value of <0.05 was considered to be statistically significant. Karamoddini et al.: Bacteriophages Against Resistant Klebsiella Species TheScientificWorldJOURNAL (2011) 11, 1332-1340 1335 RESULTS Out of the total samples that were collected during the course of the study (a period of approximately 1.5 years), 72 antibiotic-resistant Klebsiella spp. were isolated. Most of these species were isolated from urine, wounds, and burn lesion samples Karamoddini et al.: Bacteriophages Against Resistant Klebsiella Species TheScientificWorldJOURNAL (2011) 11, 1332-1340 1336 In the tube method, different concentrations (low, medium, and high) of phages were evaluated for their inhibitory effect against the growth of isolated, resistant Klebsiella spp. after 1 and 24 h of incubation at 37°C. The results indicated that in both time points, all three assessed concentrations had antibacterial effects without even one strain being unaffected by phage treatment. There was a marked increase in the antibacterial effects after 24 h compared to 1 h of incubation, and this was observed for all three assessed phage concentrations. There was also a positive association between phage concentration and observed antibacterial effects at both assessed time points. This effect of concentration was found to be of high statistical significance when comparing the antibacterial effects of low concentration to those of medium (p < 0.001) and high (p < 0.001) concentrations. However, while there was a significant concentration effect at the 1-h incubation time point between medium and high phage concentrations (p < 0.001), no significant difference was observed after 24 h of incubation (p > 0.05) ( DISCUSSION The most obvious result to emerge from the present study was the promising antibacterial effects of phages against resistant Klebsiella spp. at all assessed (low, medium, and high) concentrations. The results also indicated that bactericidal effects of phages are augmented with increasing concentration and time of incubation. In addition, the double-layer agar plate method was associated with higher bactericidal effects compared to the tube method. Bactericidal effects of phages at low concentrations are due to their self-replication property. At low concentrations, the number of phages is exponentially increased in the presence of bacterial host 1337 Phages possess some unique properties that make them promising candidates for the treatment of bacterial infections. First, they need to bind to specific surface receptors in order to enter the bacteria and exert their effects. Hence, their bactericidal effects would be specific. Second, since eukaryotic cells lack phage receptors, phage preparations appear be harmless to human, animal, and plant cells Several reports have demonstrated the efficacy of phages in the treatment of infectious diseases caused by Gram-negative bacteria, such as Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Vibrio vulnificus, and Salmonella spp., and also Gram-positive bacteria, such as Enterococcus faecium and Staphylococcus aureus 1338 In spite of the positive findings on the therapeutic efficacy of phages, this strategy has not been introduced into routine clinical practice for the treatment of bacterial infections. This stems from several reasons, the most important of which are the advent and widespread use of antibiotics in the Western world as well as the inconsistency and unsuccessful results of early trials. The main reasons for the inconsistent findings of the early trials are (1) inadequate scientific methodology that was used; (2) not heeding the prerequisites for phage therapy, such as lack of complete knowledge on phage biology, including lysogeny phenomenon (which might have led to the employment of a wrong phage); (3) lack of placebo control and robust trial design; (4) not identifying pure phage strains; (5) not meeting safety requirements for phage preparations, such as endotoxin removal; (6) not confirming adequate phage viability in the employed preparations; and (7) rapid clearance of phages from the body. The modern generation of phage research has attempted to overcome these shortcomings and promising results have been obtained. However, there is still much work to be done in order to extrapolate positive in vitro findings into more complicated in vivo experiments In recent years, there have been relatively few studies on the efficacy of phage therapy against Klebsiella infection, particularly resistant Klebsiella spp. The promising results of this investigation add to the existing body of literature about the potential efficacy of phage therapy. As Klebsiella spp. are among the most important causes of noscomial infections As a limitation of the current study, it must be mentioned that the 24-h bacterial cultures were not tested for bacteriophage resistance. Furthermore, it would be helpful to evaluate the bactericidal efficacy of phage preparations in more detailed time points. To sum, the results of this research support the idea that phages are effective bactericidal agents that could serve as potential alternatives for antibiotics in the treatment of resistant bacterial infections. In addition, the present findings provide evidence with respect to the impact of concentration, incubation duration, and method of culture on the bactericidal effects of phages. ACKNOWLEDGMENT

    Cerebral activations related to ballistic, stepwise interrupted and gradually modulated movements in parkinson patients

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    Patients with Parkinson's disease (PD) experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG) contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12) and healthy subjects (N = 18). In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN) and premotor activations while inhibition was dominated by subthalamic nucleus (STN) and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static) model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account enhanced responsiveness to external stimuli in this disease and the effects of hyper-fluctuating cortical inputs to the striatum and STN in particular

    Motivational modulation of bradykinesia in Parkinson's disease off and on dopaminergic medication.

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    Motivational influence on bradykinesia in Parkinson's disease may be observed in situations of emotional and physical stress, a phenomenon known as paradoxical kinesis. However, little is known about motivational modulation of movement speed beyond these extreme circumstances. In particular, it is not known if motivational factors affect movement speed by improving movement preparation/initiation or execution (or both) and how this effect relates to the patients' medication state. In the present study, we tested if provision of motivational incentive through monetary reward would speed-up movement initiation and/or execution in Parkinson's disease patients and if this effect depended on dopaminergic medication. We studied the effect of monetary incentive on simple reaction time in 11 Parkinson's disease patients both "off" and "on" dopaminergic medication and in 11 healthy participants. The simple reaction time task was performed across unrewarded and rewarded blocks. The initiation time and movement time were quantified separately. Anticipation errors and long responses were also recorded. The prospect of reward improved initiation times in Parkinson's disease patients both "off" and "on" dopaminergic medication, to a similar extent as in healthy participants. However, for "off" medication, this improvement was associated with increased frequency of anticipation errors, which were eliminated by dopamine replacement. Dopamine replacement had an additional, albeit small effect, on reward-related improvement of movement execution. Motivational strategies are helpful in overcoming bradykinesia in Parkinson's disease. Motivational factors may have a greater effect on bradykinesia when patients are "on" medication, as dopamine appears to be required for overcoming speed-accuracy trade-off and for improvement of movement execution. Thus, medication status should be an important consideration in movement rehabilitation programmes for patients with Parkinson's disease

    E-commerce adoption by SMEs in developing countries: evidence from Indonesia

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    This study aims to provide an overview of e-commerce adoption by SMEs in developing countries and, in particular, the extent of the adoption of e-commerce by Indonesian SMEs. It identifies the e-commerce benefits realized by these SMEs and investigates the relationship between the levels of e-commerce adoption and the benefits thus realized. The study was motivated by the limited studies related to e-commerce adoption by SMEs, especially in developing countries. In addition, it seems that most e-commerce studies are focused more on upstream issues: to see the factors that facilitate, or barriers faced regarding e-commerce adoption, rather than downstream issues: to see post-adoption benefits. This certainly limits our understanding about e-commerce adoption by SMEs in developing countries, as well as the post-adoption benefits of e-commerce. Indonesia was chosen as the place in which to conduct the study. A survey of 292 SMEs shows that the majority of them are still at an early stage in their adoption of e-commerce. Their use of e-commerce is dominated by marketing and purchasing and procurement activities. “Extending market reach”, “increased sales”, “improved external communication”, “improved company image”, “improved speed of processing”, and “increased employee productivity” are reported as the top six e-commerce benefits perceived by these SMEs. This study also shows that SMEs at the higher level of e-commerce adoption experience greater e-commerce benefits than those at other levels of adoption

    The Cognitive Role of the Globus Pallidus interna; Insights from Disease States.

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    The motor symptoms of both Parkinson's disease and focal dystonia arise from dysfunction of the basal ganglia, and are improved by pallidotomy or deep brain stimulation of the Globus Pallidus interna (GPi). However, Parkinson's disease is associated with a greater degree of basal ganglia-dependent learning impairment than dystonia. We attempt to understand this observation in terms of a comparison of the electrophysiology of the output of the basal ganglia between the two conditions. We use the natural experiment offered by Deep Brain Stimulation to compare GPi local field potential responses in subjects with Parkinson's disease compared to subjects with dystonia performing a forced-choice decision-making task with sensory feedback. In dystonic subjects, we found that auditory feedback was associated with the presence of high gamma oscillations nestled on a negative deflection, morphologically similar to sharp wave ripple complexes described in human rhinal cortex. These were not present in Parkinson's disease subjects. The temporal properties of the high gamma burst were modified by incorrect trial performance compared to correct trial performance. Both groups exhibited a robust low frequency response to 'incorrect' trial performance in dominant GPi but not non-dominant GPi at theta frequency. Our results suggest that cellular processes associated with striatum-dependent memory function may be selectively impaired in Parkinson's disease even if dopaminergic drugs are administered, but that error detection mechanisms are preserved
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