Akkihebbal K. Suresh

Why Extreme Dilutions Reach Non-zero Asymptotes: A Nanoparticulate Hypothesis Based on Froth Flotation

Extreme dilutions, especially homeopathic remedies of 30c, 200c, and higher potencies, are prepared by a process of serial dilution of 1:100 per step. As a result, dilution factors of 10(60), 10(400), or even greater are achieved. Therefore, both the presence of any active ingredient and the therapeutic efficacy of these medicines have been contentious because the existence of even traces of the starting raw materials in them is inconceivable. However, physicochemical studies of these solutions have unequivocally established the presence of the starting raw materials in nanoparticulate form even in these extreme (super-Avogadro, >10(23)) dilutions. In this article, we propose and validate a hypothesis to explain how nanoparticles are retained even at such enormous dilution levels. We show that once the bulk concentration is below a threshold level of a few nanograms/milliliter (ng/mL), at the end of each dilution step, all of the nanoparticles levitate to the surface and are accommodated as a monolayer at the top. This dominant population at the air-liquid interface is preserved and carried to the subsequent step, thereby forming an asymptotic concentration. Thus, all dilutions are only apparent and not real in terms of the concentrations of the starting raw materials.

Release rates from semi-crystalline polymer microcapsules formed by interfacial polycondensation

Microencapsulation of active agents, for their controlled release, can be brought about by the method of interfacial polycondensation [1]. In this paper, the permeabilities of the polyurea microcapsules for encapsulated cyclohexane have been determined. It is shown that the product of the permeability and membrane thickness can be changed over at least an order of magnitude by changing the degree of crystallinity of the polymer forming the membranes.

Macro‐Level and Genetic‐Level Responses of Bacillus subtilis to Shear Stress

Responses of bacterial (Bacillus subtilis) cells under different shear levels, from both the macro and genetic viewpoints, have been presented. The responses were studied using a novel, couette flow bioreactor (CFB), in which the entire cultivation can be performed under defined shear conditions. Oxygen supply, the normal limiting factor for entire cultivations under defined shear conditions, has been achieved by passing air through a poly(tetrafluoroethylene) (PTFE) membrane fixed on the inner cylinder of the CFB. More importantly, analyses of the oxygen transfer capabilities as well as the shear rates show that in this CFB, the effects of defined shear can be studied without interference from the effects of oxygen supply. Further, the shake flask can be used as a proper control for studying the shear effects, mainly because the shear rate in the shake flask under normal shaker operating conditions of 190 rpm has been estimated to be a negligible 0.028 s‐1 compared to a value of 445 s‐1 at the lowest rpm employed in the CFB. At the macro level the cell size decreased by almost 50% at 1482 s‐1 compared to that at 0.028 s‐1, the growth rate increased by 245%, and the maximum cell concentration increased by 190% when the shear rate was increased from 0.028 to 1482 s‐1. The specific intracellular catalase level increased by 335% and protease by 87% at 1482 s‐1 as compared to the control cultures at a shear rate 0.028 s‐1. In addition, the specific intracellular reactive oxygen species level (siROS) at the highest shear rate was 9.3‐fold compared to the control conditions. At the genetic level we have established the involvement of the transcription factor, σB, in the bacterial responses to shear stress, which was unknown in the literature thus far; the σB expression correlated inversely with the siROS. Further, through experiments with ROS quenchers, we showed that ROS regulated σB expression under shear.

An optimal model for representing the kinetics of growth and product formation by Lactobacillus rhamnosus on multiple substrates.

A comprehensive model was developed to simulate Lactobacillus rhamnosus growth on a medium containing multiple limiting carbon sources. The strategy of optimizing specific growth rate to predict growth on multiple substrates was demonstrated. The model predictions were based on parameters obtained from L. rhamnosus growth on individual substrates. The model was able to simulate the growth, substrate consumption, product formation and specific growth rate profiles of L. rhamnosus accurately. The model prediction that co-metabolism of glucose and pyruvate enhances growth rate of and flavor production by the bacterium was experimentally verified.

Polyureas by interfacial polycondensation: Preparation and properties

This paper concerns poly(hexamethylene) ureas produced by the technique of interfacial polycondensation. The polymer has been produced under various conditions of preparation and aspects of its structure have been elucidated using x-ray diffraction, differential scanning calorimetry, and other thermal analyses such as ther-mogravimetric analysis. The polymer has been shown to be a high-melting thermoplastic, with a melting point of about 285°C. The polymer is semicrystalline. The rate at which the polymerization takes place has an important influence on the crystal structure and the degree of crystallinity of the polymer as formed, and hence offers the possibility of manipulating the structure through a choice of preparation conditions. Chemical treatment of the formed polymer is another possible way of manipulating the structure, and some exploratory experiments on end capping show promise in this direction.

Development of high flux thin-film composite membrane for water desalination: a statistical study using response surface methodology

AbstractHigh flux thin-film composite reverse osmosis membranes for brackish water desalination have been fabricated by interfacial polymerization based on aromatic polyamide chemistry. A response surface methodology was used to optimize the concentrations of the monomers, 1,3-Diaminobenzene (MPDA) and 1,3,5-Benzenetricarbonyl trichloride (TMC), and a flux-enhancing additive, Dimethyl sulfoxide (DMSO). The membranes prepared showed a salt rejection of more than 95%. The membranes produced with DMSO additive exhibited a four- to five-fold higher flux rate as compared to the membranes without additive. Quadratic mathematical models have been proposed and verified using diagnostic plots, which adequately describe the flux rate and rejection ability within the limits of the factors investigated. The membrane rejection ability was contributed by a first-order effect of the membrane preparation parameters MPDA, TMC, and DMSO concentration, a quadratic effect of TMC and DMSO concentration, and an interaction eff...

Synthesis of silicalite-poly(furfuryl alcohol) composite membranes for oxygen enrichment from air

Silicalite-poly(furfuryl alcohol) [PFA] composite membranes were prepared by solution casting of silicalite-furfuryl alcohol [FA] suspension on a porous polysulfone substrate and subsequent in situ polymerization of FA. X-ray diffraction, nitrogen sorption, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to characterize silicalite nanocrystals and silicalite-PFA composite membranes. The silicalite-PFA composite membrane with 20 wt.% silicalite loading exhibits good oxygen/nitrogen selectivity (4.15) and high oxygen permeability (1,132.6 Barrers) at 50°C. Silicalite-PFA composite membranes are promising for the production of oxygen-enriched air for various applications.

A statistical study of the effect of preparation conditions on the structure and performance of thin film composite reverse osmosis membranes

This work describes a statistical study of the membrane formation reaction between 1,3-phenylene diamine (MPDA) and 1,3,5-benzenetricarbonyl trichloride (TMC) on polysulfone support. The membrane performance has been characterized in terms of water flux, salt passage, and intrinsic salt permeability, and the membranes were also characterized with respect to several structural and morphological factors. The ranges within which the concentration of each monomer was varied were chosen as being relevant to industrial practice, and this is borne out by the fact that the performance of the membranes formed is within the range of practical interest. This analysis reveals that the concentrations of MPDA and TMC significantly influenced the intrinsic salt permeability, water flux, and the characteristic properties of the active polyamide layer. Polynomial models have been derived for the performance parameters using response surface methodology, and allow an identification of monomer concentrations for optimal performance of the membrane.

Safety and bioactivity studies of Jasad Bhasma and its in-process intermediate in Swiss mice

ETHNOPHARMACOLOGICAL RELEVANCE Bhasma, Ayurvedic medicinal preparations, are prepared using herbs and minerals on following long iterative procedures. However, industrially mercury and sulphur are more commonly used to prepare bhasma from its raw material. The end point of this iterative procedure is mainly judged by the traditional tests specifying physical appearance of the powders. They fail to give better idea about chemical nature of the material. Moreover, the differences in biological activity of final product verses intermediate are not addressed. AIM OF THE STUDY To compare the physicochemical as well as biological properties of the Jasad bhasma and its in-process intermediate using modern science methods. MATERIALS AND METHODS The Jasad bhasma and its in-process intermediate are characterized for their physicochemical properties using electron microscopy, x-ray diffraction and CHNS(O) analysis. The biological effects of both the preparations are then studied. The bioaccumulation of zinc, effect on liver antioxidant status, liver and kidney function (by conventional tests as well as SPECT: Single Photon Emission Computed Tomography), effect on blood cells and effect on immune system are studied in mice model, Swiss albino. Since bhasma is given with an accompaniment (anupan), all the bioactivity studies were carried out by administering the preparation with and without Amala powder (Phyllanthus emblica L., fruit, dry powder) as anupan. RESULTS The XRD results accompanied with Rietveld analysis indicate that the final bhasma is mainly oxide of zinc, whereas the intermediate is mainly sulphide of zinc. The animal studies show that the bhasma as well as its intermediate do not lead to any bioaccumulation of zinc in major organs, when administered with and without anupan. Both, bhasma and intermediate do not cause any deleterious effects on kidney and liver as indicated by blood biochemistry and SPECT studies. However, the intermediate perturbs antioxidant status more and affects the platelet turnover, in comparison with bhasma. On 28day treatment, the bhasma treated animals show prominence of TH1 mediated immune response whereas, intermediate treated animals show prominence of TH2 mediated immune response. CONCLUSION A set of simple modern microscopy and diffraction techniques can affirmatively identify in-process intermediate from the final preparation. These can be used to decide the end point of long and iterative preparation methods in accordance with modern science practices. The differences in physicochemical properties of particles from the two preparations reflect in their different biological effects. Moreover, the bhasma affects several components of biological systems which again in-turn interact with each other, which emphasizes the need of multifaceted studies in this field.

A review of machines and devices to potentize homeopathic medicines

BACKGROUND Potentization, consisting of serial dilution and succussion, is a key step in the manufacture of homeopathic medicines. Originally prescribed as a manual process, several attempts at mechanization have been published, patented and even commercialised in order to remove the human element and introduce reproducibility without drudgery. Various machines have been used over the years to prepare homeopathic medicines. Although these machines follow the same principles, i.e. energetically mixing the medicines and diluting them significantly, their mode of operation is different from each other. METHODS This review paper surveys the main methods of preparation of homeopathic medicines. The main machines discussed are: Boerickes potentizer, Tyler Kents instrument, John Alphonses machine and the fluxion potentizer, which were used in the past, as well as more recent potentizers like arm-and-weight instruments, the K-Tronic potentizer and Quinns machine. We review the construction and operating principle of each of these machines, along with their advantages and limitations. A scheme for relative performance assessment of these machines is proposed based on the parameters mechanical efficiency, physico-chemical efficiency, turbulence generation, energy dissipation, and accuracy of dilution. RESULTS Quinns machine and the arm-and-weight potentizer perform well for generating turbulence due to high impaction forces, while John Alphonses machine is much more accurate in diluting the homeopathic medicines at every step. CONCLUSIONS Both the commercial potentizers, Quinns machine and the K-Tronic potentizer, are completely automated and therefore reduce the manual labour and variation in succussive forces during each step, which may produce uniformity in physico-chemical changes within the resulting homeopathic medicines.