Contrasting the dynamics of elastic and non-elastic deformations across an experimental colloidal Martensitic transition

We present a framework to segregate the roles of elastic and non-elastic deformations in the examination of real-space experiments of solid-solid Martensitic transitions. The Martensitic transformation of a body-centred-tetragonal(BCT) to a body-centred-orthorhombic(BCO) crystal structure has been studied in a model system of micron-scale ionic microgel colloids. Non-affine fluctuations, i.e., displacement fluctuations that do not arise from purely elastic(affine) deformations, are detected in particle configurations acquired from the experiment. Tracking these fluctuations serves as a highly sensitive tool in signaling the onset of the Martensitic transition and precisely locating particle rearrangements occurring at length scales of a few particle diameters. Particle rearrangements associated with non-affine displacement modes become increasingly favorable during the transformation process. The nature of the displacement fluctuation modes that govern the transformation are shown to be different from those predominant in an equilibrium crystal. We show that BCO crystallites formed through shear may, remarkably, co-exist with those resulting from local rearrangements within the same sample

Pancytopenia: a clinico hematological study

Background: Pancytopenia is very common consequence of many haematological diseases. It is the shortage of all types of blood cells. It happens in many serious and life-threatening illnesses, ranging from simple drug-induced bone marrow hypoplasia, megaloblastic anemia to fatal bone marrow aplasias and leukemias. It has different causes and severity based on which the treatment is directed and prognosis is implicated. Main objective of the study was to study the clinical presentations in pancytopenia due to various causes; and to evaluate hematological parameters, including bone marrow.Methods: It was a prospective study, and 50 pancytopenic patients were evaluated clinically, along with hematological parameters and bone marrow aspiration in Hematology Unit, Department of Pathology, Hi-Tech Medical College and Hospital, Bhubaneswar, Orissa, India during the period of October 2013 to September 2015.Results: Among 50 cases studied, age of patients ranged from 1 to 80 years with commonest age group being 41-50 years, and male predominance. Most of the patients presented with generalized weakness, pain abdomen and bleeding. Bone marrow aspiration was conclusive in all cases. The commonest marrow finding was hypocellularity followed by hypercellularity with megaloblastic erythropoiesis. The commonest cause for pancytopenia was aplastic anemia (44%), followed by mrgaloblastic anemia (20%).Conclusions: The present study concludes that detailed primary hematological investigations along with bone marrow aspiration in cytopenic patients are helpful for understanding disease process and to diagnose or to rule out the causes of cytopenia. These are also helpful in planning further investigations and management

Electrorheological responses of soft ionic colloids

N-isopropyl poly acrylamide microgel colloids exhibit strong electric-field-induced phase transitions, suggesting the possibility of a strong electrorheological response. [1] Electrorheological (ER) fluids draw researchers’ attention due to their huge potential for applications in mechanical devices, switches, valves and microfluidic chips. Please click on the file below for full content

A Soft Computing Platform for Minimizing The Bullwhip Effect

An unmanaged supply chain is not inherently stable. The bullwhip effect occurs when the demand order variability’s in the supply chain are amplified as they moved up the supply chain. Distorted information from one end of a supply chain to the other can lead to tremendous inefficiencies. In this paper it is shown that if the members of the supply chain share information with intelligent support technology, and agree on better and better soft computing technique on future sales for the upcoming period, then the bullwhip effect can be significantly reduced. This paper emphasizes on fuzzy logic technique and discusses its effect on reducing bullwhip effect. It is shown that with the application of the fuzzy logic, the multi-objective problems converted to a single one, which can be easily solved with the proposed methodology. It is also shown that linguistic values can be determined to assess vendors’ characteristics, in order to address, in an accurate way

Deuterium NMR and rheology of microgel colloids at ambient and high pressure

Microgel colloids exhibit a polymer collapse transition resulting in a large reduction in colloid size at high temperatures or pressures. Our goal is to obtain a microscopic understanding of the internal structure and microscopic dynamics of microgels by examining the temperature and pressure dependence of the collapse transition. We have conducted a systematic study of how the nature of this collapse transition is affected by crosslink density (Cd). We used deuterium NMR (2H-NMR) to probe the microscopic dynamics of cross-linked poly-N-isopropylacrylamide (p-nipam) chains, in microgel colloids, as a function of temperature and pressure. Four differently crosslinked microgels colloids were synthesized with deuteron labels on the nipam backbone (d3- nipam). Corresponding macroscopic properties of unlabeled colloids having the same crosslink densities were characterized by dynamic light scattering (DLS) and rheology. Rheological characterization as a function of temperature (T) and particle concentration (c), and for 4 crosslink densities, showed that the microgel viscosity decreases as temperature is increased, and that in the high T/low c regime, there is a collapse of the viscosity as a function of T and c when plotted against volume fraction: this yields a measure of the water content in the particles as function of T. 2H-NMR spectra of the d3-nipam suspensions for all Cd indicated freely moving chains at low temperature and a nearly immobilized fraction above 35°C. This is consistent with DLS observations of a transition from swollen to collapsed colloids. 2H-NMR spectra for the dry powder indicated totally immobilized segments in the particle. Nipam segments in the collapse phase of the d3-nipam suspension were more mobile than those in the dry powder. This suggests significant amounts of water in the collapsed phase, a finding consistent with the rheology observations. For the highest two values of Cd, microgel spectra showed the presence of an immobilized fraction of segments even in the swollen phase. Variable pressure NMR (up to 90 MPa) showed a slight increase in transition temperature with pressure for all Cd values studied

A new family of type III polyketide synthases in Mycobacterium tuberculosis

The Mycobacterium tuberculosis genome has revealed a remarkable array of polyketide synthases (PKSs); however, no polyketide product has been isolated thus far. Most of the PKS genes have been implicated in the biosynthesis of complex lipids. We report here the characterization of two novel type III PKSs from M. tuberculosis that are involved in the biosynthesis of long-chain α-pyrones. Measurement of steady-state kinetic parameters demonstrated that the catalytic efficiency of PKS18 protein was severalfold higher for long-chain acyl-coenzyme A substrates as compared with the small-chain precursors. The specificity of PKS18 and PKS11 proteins toward long-chain aliphatic acyl-coenzyme A (C12 to C20) substrates is unprecedented in the chalcone synthase (CHS) family of condensing enzymes. Based on comparative modeling studies, we propose that these proteins might have evolved by fusing the catalytic machinery of CHS and β-ketoacyl synthases, the two evolutionarily related members with conserved thiolase fold. The mechanistic and structural importance of several active site residues, as predicted by our structural model, was investigated by performing site-directed mutagenesis. The functional identification of diverse catalytic activity in mycobacterial type III PKSs provide a fascinating example of metabolite divergence in CHS-like proteins

Field-directed assembly of responsive colloids

Field-directed self-assembly (DSA) has recently moved into the focus of the soft-matter and nanotechnology community. It employs the basic principles of self-assembly through carefully chosen building blocks, but the underlying self-assembly process is then aided or modulated using external fields. Here we demonstrate how we can apply a combination of responsive nanoparticles and external electromagnetic fields in order to modulate the intrinsic interparticle interactions and tune the subtle balance between thermal motion and the action of interparticle forces, and thus generate novel self-assembled structures. We will show in particular how we can use field-driven self-assembly to induce phase transitions, cycle through various equilibrium and non-equilibrium phases, and study the micro-structural changes and the underlying kinetic mechanisms of these phase transitions in-situ and in real time. Moreover, we will demonstrate the effect of particle anisotropy in field-driven assembly. References [1] J. J. Crassous, A. M. Mihut, E. Wernersson, P. Pfleiderer, J. Vermant, P. Linse, and P. Schurtenberger, Nature Communications 5 (2014) 5516. [2] P. S. Mohanty, P. Bagheri, S. Nöjd, A. Yethiraj and P. Schurtenberger, Phys. Rev. X 5 (2015) 011030

Plant growth promoting activities of P solubilizing bacteria and their impact on disease resistance in groundnut, <i>Arachis hypogaea</i> L. against soil borne fungal pathogens

606-616Plant growth promoting (PGP) activities of soil bacteria directly help plants in taking up the nutrients, attuning the growth hormones and indirectly safeguard by inhibiting diverse groups of fungal pathogens. In this study, we explored the native P solubilizing bacteria (PSB) isolated from the acid soils (pH 3(PO4)2,AlPO4,FePO4 and Fe3(PO4)2. The bioconversion of P by all the five strains in the broth medium followed the order Ca-P > Fe(III)-P > Fe(II)-P >Al-P. The strains interestingly showed potential plant growthpromoting properties including indole acetic acid (IAA) andsiderophore production in in vitro tests. These five strains also exhibited antifungal activities against fungal pathogens(Pythium aphanidermatum, Fusarium oxysporum, Pythium debaryanum, Thanatephorus cucumeris and Aspergillus niger)of groundnut. A field study was carried out with two of the above PSB strains [identified as Bacillus amyloliquefaciens(KT633845) and Burkholderia cepacia (KT717633)] with groundnut. Both the stains significantly influenced the plantgrowth (plant height, nodule no. and nodule dry weight) and pod yield. However, these two strains inoculated along withdoses of inorganic phosphate (SSP, single super phosphate) resulted in significantly higher pod yield as well as residual soil P.Additionally; the prevalence of both seedling mortality and plant mortality due to collar rot and stem rot were found to bereduced significantly in the inoculated plots. The findings substantiate the growth promoting ability of the two P solubilizingstrains, and thus qualifies to be used as biofertilizers either alone or as components of INM practices

Plant growth promoting activities of P solubilizing bacteria and their impact on disease resistance in groundnut, Arachis hypogaea L. against soil borne fungal pathogens

Plant growth promoting (PGP) activities of soil bacteria directly help plants in taking up the nutrients, attuning the growth hormones and indirectly safeguard by inhibiting diverse groups of fungal pathogens. In this study, we explored the native P solubilizing bacteria (PSB) isolated from the acid soils (pH &lt; 5.5) of Odisha for selection of efficient PGPR with antifungal potential. Five PSB strainswere checked for their P solubilization efficiencies with Ca3(PO4)2,AlPO4,FePO4 and Fe3(PO4)2. The bioconversion of P by all the five strains in the broth medium followed the order Ca-P &gt; Fe(III)-P &gt; Fe(II)-P &gt;Al-P. The strains interestingly showed potential plant growthpromoting properties including indole acetic acid (IAA) andsiderophore production in in vitro tests. These five strains also exhibited antifungal activities against fungal pathogens(Pythium aphanidermatum, Fusarium oxysporum, Pythium debaryanum, Thanatephorus cucumeris and Aspergillus niger)of groundnut. A field study was carried out with two of the above PSB strains [identified as Bacillus amyloliquefaciens(KT633845) and Burkholderia cepacia (KT717633)] with groundnut. Both the stains significantly influenced the plantgrowth (plant height, nodule no. and nodule dry weight) and pod yield. However, these two strains inoculated along withdoses of inorganic phosphate (SSP, single super phosphate) resulted in significantly higher pod yield as well as residual soil P.Additionally; the prevalence of both seedling mortality and plant mortality due to collar rot and stem rot were found to bereduced significantly in the inoculated plots. The findings substantiate the growth promoting ability of the two P solubilizingstrains, and thus qualifies to be used as biofertilizers either alone or as components of INM practice

Synthesis and characterization of novel functional electrosterically stabilized colloidal particles prepared by emulsion polymerization using a strongly ionized amphiphilic diblock copolymer

Amphiphilic diblock copolymers such as poly(styrene)-block-poly(styrene sulfonate) (PS-b-PSS) (Matsuoka, H.; Maeda, S.; Kaewsaiha, P.; Matsumoto, K. Langmuir 2004, 20, 7412), belong to a class of new polymeric surfactants that ionize strongly in aqueous media. We investigated their self-assembly behavior in aqueous solutions and used them as an emulsifier to prepare electrosterically stabilized colloidal particles of different diameters between 70 to 400 nm. We determined the size, size polydispersity, effective charge, total dissociable charge, structural ordering, and phase behavior using light scattering, transmission electron microscopy (TEM), small-angle neutron scattering (SANS), and potentiometric titration. These experiments clearly demonstrated that all of the synthesized particles were nearly monodisperse (polydispersity index ≤ 6%). The results of DLS and TEM clearly suggested the existence of hairy particles. The form factors obtained by SANS were well described by a polydisperse sphere model. The estimated total number of dissociable charges per particle was found to be larger than 10⁴e, whereas the effective charges per particle were found to be around 1000e. This significant difference suggested the confinement of charges inside the corona regions of the polyelectrolyte brush shell. Finally, these monodisperse particles were found to self-assemble into 3D ordered colloidal crystalline arrays at a low volume fraction (= 0.00074) that diffract light in the visible region