1,167 research outputs found
Isolation and characterization of nitrogen fixing bacteria from raw coir pith
Coir fibre is the hard fibre extracted from the coconut husk and coir pith is a lignocellulosic byproduct released during the extraction of coir fibre. The pith is not degraded under normal environmental conditions and accumulates in the fibre extraction units occupying sprawling space in the units. The inherent properties of coir pith make it useful as a plant nutrient. Nitrogen fixing bacteria could be isolated from the coir pith and four strains were amplified with nifH gene viz. NF-4 (Lysinibacillus sp.), NF-7 (Ochrobactrum sp.), NF-12 (Paenibacillus sp.) and an uncultured bacterial clone which shows only 50% similarity to NF-18 (Clostridium sp). The present study targeted the isolation and characterization of natural flora of nitrogen fixing organisms in the coir pith.Key words: Coir pith, nifH gene, nitrogen fixation, organic manure
NMR identification of calcineurin B residues affected by binding of a calcineurin A peptide
AbstractTriple resonance 3D NMR methods have been used to study the interaction between calcineurin B and a peptide fragment of calcineurin A for which it has high affinity (KD ∼4 × 10−7 M). Although calcineurin B aggregates at NMR concentrations of ∼ 1 mM, in the presence of a target peptide fragment of calcineurin A it becomes monomeric and yields NMR spectra that are very similar to those reported previously for calcineurin B solubilized by the zwitterionic detergent CHAPS. Changes in chemical shifts between CHAPS- and peptide-solubilized calcineurin B are small which is indicative of no differences in secondary structure. Residues most affected by binding to target peptide are found primarily on the hydrophobic faces of the four helices, present in each of the two globular domains in calcineurin B, and in the loops connecting helices II and III, IV and V, and possibly in the C-terminal 12 residues, which also exhibit a change in mobility
Functional Analysis of Spontaneous Cell Movement under Different Physiological Conditions
Cells can show not only spontaneous movement but also tactic responses to
environmental signals. Since the former can be regarded as the basis to realize
the latter, playing essential roles in various cellular functions, it is
important to investigate spontaneous movement quantitatively at different
physiological conditions in relation to cellular physiological functions. For
that purpose, we observed a series of spontaneous movements by Dictyostelium
cells at different developmental periods by using a single cell tracking
system. Using statistical analysis of these traced data, we found that cells
showed complex dynamics with anomalous diffusion and that their velocity
distribution had power-law tails in all conditions. Furthermore, as development
proceeded, average velocity and persistency of the movement increased and as
too did the exponential behavior in the velocity distribution. Based on these
results, we succeeded in applying a generalized Langevin model to the
experimental data. With this model, we discuss the relation of spontaneous cell
movement to cellular physiological function and its relevance to behavioral
strategies for cell survival.Comment: Accepted to PLoS ON
Visual art inspired by the collective feeding behavior of sand-bubbler crabs
Sand--bubblers are crabs of the genera Dotilla and Scopimera which are known
to produce remarkable patterns and structures at tropical beaches. From these
pattern-making abilities, we may draw inspiration for digital visual art. A
simple mathematical model is proposed and an algorithm is designed that may
create such sand-bubbler patterns artificially. In addition, design parameters
to modify the patterns are identified and analyzed by computational aesthetic
measures. Finally, an extension of the algorithm is discussed that may enable
controlling and guiding generative evolution of the art-making process
Coherent Moving States in Highway Traffic (Originally: Moving Like a Solid Block)
Recent advances in multiagent simulations have made possible the study of
realistic traffic patterns and allow to test theories based on driver
behaviour. Such simulations also display various empirical features of traffic
flows, and are used to design traffic controls that maximise the throughput of
vehicles in heavily transited highways. In addition to its intrinsic economic
value, vehicular traffic is of interest because it may throw light on some
social phenomena where diverse individuals competitively try to maximise their
own utilities under certain constraints.
In this paper, we present simulation results that point to the existence of
cooperative, coherent states arising from competitive interactions that lead to
a new phenomenon in heterogeneous highway traffic. As the density of vehicles
increases, their interactions cause a transition into a highly correlated state
in which all vehicles practically move with the same speed, analogous to the
motion of a solid block. This state is associated with a reduced lane changing
rate and a safe, high and stable flow. It disappears as the vehicle density
exceeds a critical value. The effect is observed in recent evaluations of Dutch
traffic data.Comment: Submitted on April 21, 1998. For related work see
http://www.theo2.physik.uni-stuttgart.de/helbing.html and
http://www.parc.xerox.com/dynamics
"My Children and I Will no Longer Suffer from Malaria": A Qualitative Study of the Acceptance and Rejection of Indoor Residual Spraying to Prevent Malaria in Tanzania.
The objective of this study was to identify attitudes and misconceptions related to acceptance or refusal of indoor residual spraying (IRS) in Tanzania for both the general population and among certain groups (e.g., farmers, fishermen, community leaders, and women). This study was a series of qualitative, semi-structured, in-depth interviews and focus group discussions conducted from October 2010 to March 2011 on Mainland Tanzania and Zanzibar. Three groups of participants were targeted: acceptors of IRS (those who have already had their homes sprayed), refusers (those whose communities have been sprayed, but refused to have their individual home sprayed), and those whose houses were about to be sprayed as part of IRS scale-up. Interviews were also conducted with farmers, fishermen, women, community leaders and members of non-government organizations responsible for community mobilization around IRS. Results showed refusers are a very small percentage of the population. They tend to be more knowledgeable people such as teachers, drivers, extension workers, and other civil servants who do not simply follow the orders of the local government or the sprayers, but are skeptical about the process until they see true results. Refusal took three forms: 1) refusing partially until thorough explanation is provided; 2) accepting spray to be done in a few rooms only; and 3) refusing outright. In most of the refusal interviews, refusers justified why their houses were not sprayed, often without admitting that they had refused. Reasons for refusal included initial ignorance about the reasons for IRS, uncertainty about its effectiveness, increased prevalence of other insects, potential physical side effects, odour, rumours about the chemical affecting fertility, embarrassment about moving poor quality possessions out of the house, and belief that the spray was politically motivated. To increase IRS acceptance, participants recommended more emphasis on providing thorough public education, ensuring the sprayers themselves are more knowledgeable about IRS, and asking that community leaders encourage participation by their constituents rather than threatening punishment for noncompliance. While there are several rumours and misconceptions concerning IRS in Tanzania, acceptance is very high and continues to increase as positive results become apparent
Nonattendance in pediatric pulmonary clinics: an ambulatory survey
<p>Abstract</p> <p>Background</p> <p>Nonattendance for scheduled appointments disturbs the effective management of pediatric pulmonary clinics. We hypothesized that the reasons for non-attendance and the necessary solutions might be different in pediatric pulmonary medicine than in other pediatric fields. We therefore investigated the factors associated with nonattendance this field in order to devise a corrective strategy.</p> <p>Methods</p> <p>The effect of age, gender, ethnic origin, waiting time for an appointment and the timing of appointments during the day on nonattendance proportion were assessed. Chi-square tests were used to analyze statistically significant differences of categorical variables. Logistic regression models were used for multivariate analysis.</p> <p>Results</p> <p>A total of 1190 pediatric pulmonology clinic visits in a 21 month period were included in the study. The overall proportion of nonattendance was 30.6%. Nonattendance was 23.8% when there was a short waiting time for an appointment (1–7 days) and 36.3% when there was a long waiting time (8 days and above) (p-value < 0.001). Nonattendance was 28.7% between 8 a.m. to 3 p.m. and 37.5% after 3 p.m. (p = 0.007). Jewish rural patients had 15.4% nonattendance, Jewish urban patients had 31.2% nonattendance and Bedouin patients had 32.9% nonattendance (p < 0.004). Age and gender were not significantly associated with nonattendance proportions. A multivariate logistic regression model demonstrated that the waiting time for an appointment, time of the day, and the patients' origin was significantly associated with nonattendance.</p> <p>Conclusion</p> <p>The factors associated with nonattendance in pediatric pulmonary clinics include the length of waiting time for an appointment, the hour of the appointment within the day and the origin of the patient.</p
The systemic lupus erythematosus IRF5 risk haplotype is associated with systemic sclerosis
Systemic sclerosis (SSc) is a fibrotic autoimmune disease in which the genetic component plays an important role. One of the strongest SSc association signals outside the human leukocyte antigen (HLA) region corresponds to interferon (IFN) regulatory factor 5 (IRF5), a major regulator of the type I IFN pathway. In this study we aimed to evaluate whether three different haplotypic blocks within this locus, which have been shown to alter the protein function influencing systemic lupus erythematosus (SLE) susceptibility, are involved in SSc susceptibility and clinical phenotypes. For that purpose, we genotyped one representative single-nucleotide polymorphism (SNP) of each block (rs10488631, rs2004640, and rs4728142) in a total of 3,361 SSc patients and 4,012 unaffected controls of Caucasian origin from Spain, Germany, The Netherlands, Italy and United Kingdom. A meta-analysis of the allele frequencies was performed to analyse the overall effect of these IRF5 genetic variants on SSc. Allelic combination and dependency tests were also carried out. The three SNPs showed strong associations with the global disease (rs4728142: P = 1.34×10<sup>−8</sup>, OR = 1.22, CI 95% = 1.14–1.30; rs2004640: P = 4.60×10<sup>−7</sup>, OR = 0.84, CI 95% = 0.78–0.90; rs10488631: P = 7.53×10<sup>−20</sup>, OR = 1.63, CI 95% = 1.47–1.81). However, the association of rs2004640 with SSc was not independent of rs4728142 (conditioned P = 0.598). The haplotype containing the risk alleles (rs4728142*A-rs2004640*T-rs10488631*C: P = 9.04×10<sup>−22</sup>, OR = 1.75, CI 95% = 1.56–1.97) better explained the observed association (likelihood P-value = 1.48×10<sup>−4</sup>), suggesting an additive effect of the three haplotypic blocks. No statistical significance was observed in the comparisons amongst SSc patients with and without the main clinical characteristics. Our data clearly indicate that the SLE risk haplotype also influences SSc predisposition, and that this association is not sub-phenotype-specific
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