Persistent organochlorine pesticide residues in milk and dairy products in India

Monitoring of milk and dairy product samples of various brands from different cities in Maharashtra, India, was carried out to determine if there is any contamination due to organochlorine pesticide residues. The measurements were made using a gas chromatograph-electron capture detector system. Trace levels of DDT and HCH were detected in the samples. Total HCH levels in milk and milk product samples were lower than total DDT levels, which could be attributed to earlier extensive antimalaria sanitary activities. Butter had higher levels of DDT than cheese and milk powder. All levels of organochlorine pesticide residues in milk and milk products were well below the maximum permissible limits given by the FAO/WHO. More importantly, as compared with an earlier report, present levels of the contaminants are substantially lower, which indicate the gradual phase out of these compounds.     

Use of tissue transglutaminase and fibronectin to influence osteoblast responses to tricalcium phosphate scaffolds

To explore the possibility of controlling cell interaction with biomaterials, tricalcium phosphate scaffolds were modified using the enzyme tissue transglutaminase (tTgase) in conjunction with fibronectin. Previous reports in the literature have highlighted a number of favourable responses that this protein-enzyme complex can stimulate, including enhancing both cell adhesion, and mineralisation. Fibronectin and tTgase alone were used as controls, and a series of different concentrations of tTgase and fibronectin in combination were assessed. Cell metabolic activity, alkaline phosphatase production, and collagen content were all measured in cultures up to 28 days. Using tetracycline labelling, calcium containing multilayered regions were imaged and quantified. Addition of 6 microg fibronectin resulted in increased alkaline phosphatase activity in all combinations, while increased transglutaminase resulted in more collagen in the cell lysates. Samples treated with fibronectin produced many small mineralised areas, those with 6 microg fibronectin and transglutaminase produced numerous large mineralised areas. The mixture of fibronectin and transglutaminase may prove to be a useful treatment for producing increased osteoblast differentiation on scaffolds.     

Destruction of formic acid using high frequency cup horn reactor

Degradation of formic acid has been studied in a high frequency cup horn type reactor with an aim of understanding the effect of operating parameters on the destruction efficiency. The methodology used in the work serves as a useful guideline for the optimization exercise for the sonochemical reactors to establish a set of operating parameters at large scale operation for achieving maximum efficiency. Firstly energy efficiency of the reactor has been established as a function of the operating volume with an aim of optimization of the capacity of the reactor for maximum extent of degradation. It has been observed that maximum transfer of supplied power is obtained at 300 ml capacity and hence the actual degradation studies have been performed with this operational capacity. The effect of time of irradiation, initial concentration of the pollutant, stirrer speed, presence of sodium sulfite (to scavenge the initial dissolved oxygen) on the extent of degradation has been investigated. Maximum extent of degradation has been observed under the conditions of 500 mg/l initial concentration, 200 rpm stirrer speed and presence of initial dissolved oxygen (no sodium sulfite in the system). Process intensification studies have been carried out using sodium chloride over a range of initial concentration and it has been observed that maximum extent of degradation of formic acid is obtained at 4% NaCl concentration. Comparison has been also made with different sonochemical configurations operating at lower frequency of irradiation (typically in the range of 20-50 kHz) with an aim of comparing the efficacies of the reactor at equivalent power consumption.     

Effect of Secondary Structure and Side Chain Length of Hydrophobic Amino Acid Residues on the Antimicrobial Activity and Toxicity of 14-Residue-Long de novo AMPs

Herein we report the efficacy and toxicity of three de novo designed cationic antimicrobial peptides (AMPs) LL-14, VV-14 and ββ-14, where side chains of the hydrophobic amino acids were reduced gradually. The AMPs showed broad-spectrum antimicrobial activity against three pathogens from the ESKAPE group and two fungal strains. This study showed that side chains which are either too long or too short increase toxicity and lower antimicrobial activity, respectively. VV-14 was found to be non-cytotoxic and highly potent under physiological salt concentrations against several pathogens, especially Salmonella typhi TY2. These AMPs acted via membrane deformation, depolarization, and lysis. The activity of the AMPs is related to their ability to take on amphipathic helical conformations in the presence of microbial membrane mimics. Among AMPs with the same charge, hydrophobic interactions between the side chains of the residues with cell membrane lipids determine their antimicrobial potency and cytotoxicity. Strikingly, an optimum hydrophobic interaction is the crux of generating highly potent non-cytotoxic AMPs.     

An extension of the graph theoretical approach to predict the secondary structure of large RNAs: the complex of 16S and 23S rRNAs from E. coli as a case study

An algorithm using the graph theoretical approach to predict secondary structures of large nucleic acids is discussed. Reliability of prediction can be improved by incorporating available experimental data and sequence homology information. As a case study, this algorithm is applied to predict the secondary structure of the 16S-23S rRNA complex from E. coli. It was found that several structures of the complex can coexist. The computer program developed to predict the secondary structure of large RNAs can be run on IBM PC/AT compatible systems.     

Surfactant Solutions as Media for Dissolution Testing of A Poorly Water-Soluble Drug

The solubility of a poorly water soluble drug. 4-(4-biphenylyl)-butanol (I) was dramatically enhanced in the presence of anionic, cationic and non-ionic surfactants. Since I has no bioavailability problems on oral dosing of capsules, physiological surfactants may be involved in the solubilization of I in vivo. Thus, surfactant solutions were selected as the most relevant media for dissolution testing of capsules of I. The intrinsic dissolution of I was examined in water, sodium dodecyl sulfate (SDS), and polyoxyethylene lauryl ether (POE lauryl ether) solutions, and increases were observed. Capsule dissolution in SDS solutions was not very successful: possible reasons are discussed. POE lauryl ether was selected as the surfactant of choice. The intrinsic dissolution rates were not a linear function of concentration of POE lauryl ether in the medium. Reasons for these observations are discussed. Dissolution of capsules was examined in various concentrations of the surfactant and an optimum concentration selected.     

Fibrolamellar carcinoma of the liver--an unusual presentation

Non-bacterial thrombotic endocarditis was found at autopsy in a 17 year old male patient of fibrolamellar type of hepatocellular carcinoma with pericardial metastases. This had resulted in multiple embolic cerebral infarcts with long standing hemiplegia and later death due to acute left ventricular failure.     

Analysis of repeating oligonucleotide sequences in ribonucleic acids using an Apple II microcomputer

A simple computer program has been developed to locate repeating subsequences of all possible lengths in a given nucleic acid. The observed number of repeats of subsequences was compared with the expected number of such repeats in several RNAs. The analysis showed that, in the case of rRNAs, there are no constraints in the choice of the fourth and the higher order nucleotides, while the selection is maximum at the level of nearest neighbour. This is, however, not true for RNAs coding for proteins, where the constraints are also found at the level of nucleotides containing five or more bases.     

Data-dependent-systems and Fourier-transform methods for single-interferogram analysis

Results of wave-front phase detection obtained from a spatial method based on data-dependent-systems (DDS) methodology are compared with those obtained from the Fourier-transform method. DDS is a novel approach that extends and improves the way the stochastic autoregressive moving-average models are obtained and interpreted. The methodology is robust to noise influence and insensitive to the errors commonly associated with the Fourier transform. Both the Fourier-transform and the DDS methods use one interference pattern, and both offer means for filtering out disturbances such as noise and background variations. We present a brief review of the two methods to compare them theoretically, and then we describe their experimental implementation. The methods were applied to the same interferometric data sets, and the results are presented and compared to discuss relative advantages and disadvantages. In particular, it is shown that the DDS method preserves the detailed surface texture because a convolution of the component that represents the surface dynamic aspect with the component that corresponds to the independent and dynamic-free aspect is able to recover the original details. In contrast the Fourier-transform method smooths such details to an extent that depends on the subjective choice of filters.     

Interferogram analysis based on the data-dependent systems method for nanometrology applications

A spatial method of wave-front phase detection from an interferogram is presented. The method uses data-dependent systems methodology, an approach that extends and improves the way the stochastic autoregressive moving average models are obtained and interpreted. Its application to interference data addresses the fundamental problem of recovering the self-coherence function commonly used to retrieve the wave-front phase. The self-coherence function is efficiently computed by means of a complex autoregressive model and is used for surface reconstruction. The method is shown to be robust and suitable for surface testing. The correspondence of the data-dependent systems methodology and its physical meaning as related to the classical interferometry are presented. The theoretical development is illustrated by experimental implementation, with the results obtained from one- and two-dimensional interferometric fringe analysis of a computer hard disk.