Thermal degradation of waste plastics under non-sweeping atmosphere: Part 1: Effect of temperature, product optimization, and degradation mechanism.

Continuous generation of plastic waste has prompted substantial research efforts in its utilization as a feedstock for energy generation. Pyrolysis has emerged as one of the best waste management technique for energy extraction from the plastic waste. The objective of this work is to investigate the effect of operating temperature on the liquid product yields in the pyrolysis process by non-isothermal heating. Non-catalytic thermal pyrolysis of waste polyethylene (PE) [high density polyethylene (HDPE)], waste polypropene (PP), waste polystyrene (PS), waste polyethylene terephthalate (PET) and mixed plastic waste (MPW) was carried out in a non-sweeping atmosphere in a semi-batch reactor at four different temperatures 450, 500, 550, and 600 °C. The minimum degradation temperature of the mixed and individual plastics was obtained using a thermogravimetric apparatus (TGA) at a heating rate of 20 °C/min. The TGA results show that all plastics degrade in a single step and the degradation temperatures of PS > PET > PP > HDPE, while mixed plastic degradation indicates two distinct degradation steps. Further, a waste polymer shows a lower degradation temperature than the virgin polymer. The degradation of HDPE is found to produce the maximum oil yield with minimum solid residue. The degradation of PET results in the highest amount of solid and benzoic acid as crystals and gas with no oil. Degradation of mixed plastic causes oil yield in the intermediate range of pyrolysis of individual plastic wastes. Overall, 500 °C is observed to be an optimum temperature for the recovery of low-density pyrolytic oil with the highest liquid yield. The degradation of PE and PP is found to be caused by random chain scission followed by inter and intramolecular hydrogen transfer. The degradation of PS occurs by side elimination or end chain scission followed by ß-scission mechanism. The degradation of mix plastics results from random chain scission followed by ß-scission mechanism. The effect of temperature on oil and gas recovery as well as recovery time was also assessed.

EMG characteristics and fibre composition: study on rectus femoris of sprinters and long distance runners.

The study was conducted on 9 sprinters and 5 long distance runners to investigate the difference in power spectral characteristics of rectus femoris muscle and the feasibility of using electromyographic techniques in categorization of muscle groups in slow dominant and fast dominant types. EMG signal was recorded, after digitization at 4 KHz, from rectus femoris muscle during isometric knee extension (at maximum voluntary contraction level) until fatigue. Digitized signal was processed for Fast Fourier Transform and Root Mean Square (RMS) voltage. Significant difference (P < 0.05) was found in RMS voltage between sprinters and long distance runners. Both groups showed decline in Mean Power Frequency (MPE) and rate of decline in sprinters was rapid. Normalized MPF showed better discrimination between the two groups. It is concluded that the EMG response observed in this study was possibly a result of differences in the muscle fibre composition of the athletes. EMG study using spectral characteristics would be useful in categorizing the sports persons in terms of suitability of the events.

Butyrolactones from Aspergillus terreus.

In the process development of lovastatin using Aspergillus terreus DRCC 152 in solid state fermentation, we have isolated a new butyrolactone-IV (3) along with the previously reported butyrolactone-I (1) and butyrolactone-II (2) produced under submerged conditions. The structure of compound 3 has been characterized as 3-hydroxy-5-[2-(1-hydroxy-1-methylethyl)-2(R)-2,3-dihydro-benzo[b]furan- 5 ylmethyl]-4-(4-hydroxyphenyl)-5-methoxycarbonyl-(5R)-2,5-dihydro-2 -furanone on the basis of spectroscopic studies. The absolute stereochemistry has been determined by single crystal X-ray diffraction studies. The cytotoxic and antibacterial activities of these compounds were determined.

A rapid technique for screening of lovastatin-producing strains of Aspergillus terreus by agar plug and Neurospora crassa bioassay.

The success of strain improvement programme depends on the number of isolates that can be screened after mutagenic treatment. A technique to rapidly screen large number of high-yielding isolates was developed. The 'agar plug' method that utilizes the anti-fungal property of lovastatin to produce a zone of inhibition against Neurospora crassa was not only economical but also less labour-intensive. We were able to isolate a high-yielding strain, the productivity of which increased by 138% as compared to the parent strain in the submerged fermentation process.

Novel quinolone derivatives as potent antibacterials.

Several 7-(3R,4R-N,N'-dialkyl diaminopyrrolidinyl)-substituted quinolones were synthesized and evaluated for antibacterial activities. 5-Amino-7-(3R,4R-N,N'-dimethyldiamino-6,8-difluoro-1,4-dihydro-1-c yclopropyl -4-oxoquinoline-3-carboxylic acid was found to have potent antibacterial activity against gram +ve organisms.

Comparative study of lactate removal in short term massage of extremities, active recovery and a passive recovery period after supramaximal exercise sessions.

This investigation highlights the comparison of blood lactate removal during the period of recovery in which the subjects were required to sit down as a passive rest period, followed by active recovery at 30% VO(2)max and short term body massage, as the three modes of recovery used. Ten male athletes participated in the study. Exercise was performed on a bicycle ergometer with loads at 150% VO(2)max, each session lasting 1 min, interspaced with 15 sec rest periods, until exhaustion. Blood lactate concentration was recorded at recovery periods of 0,3, 5, 10, 20, 30, and 40 min, while VO(2), VCO(2) and heart rate were recorded every 30 sec for 30 min. The highest mean lactate value was found after 3 min of recovery irrespective of the type of modality applied. Significantly lower half life of lactate was observed during active recovery (15.7 +/- 2.5 min) period, while short term massage as a means of recovery required 21.8 +/- 3.5 min and did not show any significant difference from a passive type of sitting recovery period of 21.5 +/- 2.8 min. Analysis of lactate values indicated no remarkable difference between massage and a passive type of sitting recovery period. It was observed that in short term massage recovery, more oxygen was consumed as compared to a passive type of sitting recovery. It is concluded from the study that the short term body massage is ineffective in enhancing the lactate removal and that an active type of recovery is the best modality for enhancing lactate removal after exercise.

Technical communication: A simple and economically viable medium for the growth of Agrobacterium radiobacter for the production of D-amino acid.

A simple and cost effective medium for the growth and D-amino acid production by Agrobacterium radiobacter from hydantoin is reported. The effectiveness of this medium is compared with other synthetic media.

Effect of sampling frequency on EMG power spectral characteristics.

During digitization of surface EMG, the signal is converted by an Analog-to-Digital (A/D) convertor at a specific sampling rate. This sampling rate should be selected cautiously because a high rate may include noise signals and a low rate may lead to errors. The present study was undertaken to show the effect of sampling rate on EMG power spectrum. The study was carried out on nine subjects and EMG record was done from deltoid muscle at sampling rates of 4, 6, 8 and 10 KHz during maximal voluntary contraction. Biopotential coupler with a response range of 5 Hz to 2 KHz was used during recording of the EMG signal which was processed later by Fast Fourier Transform software. The study showed a linear relationship between the sampling rate and the mean power frequency (MPF). But there was no distinct effect of sampling rate on mean and root mean square (RMS) of the digitized signal.

Inhibitory effects of tea extracts and (-)-epigallocatechin gallate on DNA synthesis and proliferation of hepatoma and erythroleukemia cells.

Polyphenols extracted from green or black tea with ethyl acetate were strongly inhibitory for DNA synthesis in HTC rat hepatoma cells and DS19 mouse erythroleukemia cells at concentrations of 0.1-0.2 mg/ml. There was less inhibition with a subsequent black tea fraction extracted with butanol and with the residual water-soluble fraction. Although cell proliferation was inhibited by (-)-epigallocatechin gallate and the tea extracts, there were only marginal effects on differentiation of DS19 cells as judged by hemoglobin synthesis.

Butyramide and monobutyrin: growth inhibitory and differentiating agents.

Butyramide and monobutyrin were chosen for study as neutral compounds that might exhibit some of the growth inhibitory and differentiating effects of butyrate. Inhibitory effects on DNA synthesis in hepatoma cells and on cellular proliferation in mouse erythroleukemia cells were observed. Induction of differentiation by butyramide and monobutyrin was seen in mouse erythroleukemia cells as monitored by increased synthesis of hemoglobin and H1 zero histone. Butyramide and monobutyrin were less effective inducers of hemoglobin synthesis than butyrate but their neutral character may offer an advantage in the induction of tumor cell differentiation.