Poly(lactic acid) (PLA) was synthesized using condensation polymerization of L-lactic acid using a controlled ultrasonic cavitation technique. Polystyrene (PS) was used to prepare the PS:PLA and PS:PLA:organically modified montmorillonite (OMMT) composites. PS was dissolved in benzene (10:90) and kept overnight for dissolution. Meanwhile, surface modification of montmorillonite was done using a column chromatography technique and referred to as OMMT. The d-spacing was found to be 22 Å after modification due to sufficient column length and diameter with good retention time during ion exchange. PLA and OMMT were kept in hot air oven at 100 o C for 30 min to remove the moisture. The mixtures of 10%, 15%, 20%, 25%, and 30% of PS:PLA:OMMT were subjected to ultrasonic irradiation (50 Hz) for homogenization and to form a biodegradable polymer nanocomposite sheet (5 × 5 cm 2 ). The amount of OMMT loading was from 0.5-5 mass%. These composites were subjected to degradation in minimal medium using Pseudomonas aeruginosa bacteria at controlled conditions, and the polymer is a major source of carbon. The degradation was confirmed using scanning electron microscopy, extracellular protein content change, biomass production, and % degradation with respect to time (up to 28 days) after incubation.
Circulatory levels of LH and FSH were measured in serum of male rats (28, 35, 42, 63, 70, 77, and 207 days of age) 7 days following sham operation, castration (C), prostatectomy (P), and castration + prostatectomy (C + P). In C + P rats that were 49, 63, 70, 77, and 207 days of age, the plasma FSH was significantly elevated as compared to the C group. Administration of aqueous prostatic extract restored the circulatory FSH level in C + P animals to that observed in C animals, whereas in C animals FSH levels were suppressed, indicating inhibinlike activity. In rats 49 and 77 days of age, circulatory LH levels were significantly suppressed in C + P animals as compared to the C group. Both castration and prostatectomy alone suppressed circulatory prolactin levels. Administration of prostatic extract to castrated animals restored the prolactin levels to that of the sham-operated control animals. Results of the present study suggest a role of the prostate in feedback regulation of FSH and prolactin.
Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by (1)H and (13)C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.
The half-life and metabolic clearance rate of human seminal plasma inhibin after injection into male rats was studied. Labeled inhibin was injected i.v. into 27-day-old rats (10 ng, 3.5 X i0 cpm)and 75-day-old rats (15 ng, 5.5 X i0 cpm). In both age groups, rats were killed at intervals between
Phenazines are nitro aromatic redox-active antibiotics produced under the control of quorum sensing mechanism by a diverse range of bacterial genera with various color intensities varies from blue, green, purple, yellow, red to even brown. Production of phenazine showed (1) taxonomic value when related to few genera, (2) functional role in environment and (3) bioactive potential with respect to structure; however due to poor structural understanding its correlation is still incomplete with diversity and bioactivity. Thus isolation and identification of phenazine antibiotic is highly desirable. Current chapter resolves the methodologies for various phenazines isolation as well as its identification through different spectroscopic and electrophoretic methods in different bacterial systems.
Abbreviations
MS
Mass spectrometry EI-MSElectron impact mass spectroscopy HRMS High-resolution mass spectrometry FI MS Field ionization mass spectrometry HRESIMS High resolution electron spray ionization mass spectroscopy LRCIMS Low resolution chemical ionization mass spectrometry HRCIMS High resolution chemical ionization mass spectrometry HR-FAB-MS High resolution fast atom bombardment mass spectrum DCI-MS Desorption-chemical ionization mass spectrometry LC/MS
Two low-molecular-weight gonadal peptides, IRRP3 and IRRPS, have been isolated from sheep ovaries having different biological properties in male rats. The peptide IRRP3 has specific effect on (1) FSH secretion as well as release at the pituitary level, (2) in vitro binding of labeled FSH to testicular receptor, and (3) in vivo uptake of labeled FSH by the testis, whereas peptide IRRPS has specific effect on (1) LH secretion at the pituitary level, (2) in vitro binding of labeled LH to testicular receptor, and (3) in vivo uptake of labeled LH by the testis.
Phanerochaete chrysosporium species was used to study the degradation of polymeric composites of (a) isotactic polypropylene (iPP) and (PLA) (iPP/PLA), and (b) iPP/PLA filled with calcium carbonate nanoparticles (nCaCO 3 ). PLA was synthesized using L-lactic acid under the controlled ultrasound cavitation technique, dried and used for composite preparation. Meanwhile, the synthesis and subsequent surface modification of nCaCO 3 was done using the ultrasound cavitation technique. Owing to ultrasound cavitation, a reaction mixture is dispersed uniformly but at the same time strong electrostatic force of attraction is developed over the surface of nCaCO 3 particles, which forms the agglomeration of particles. The deagglomeration as well as charge nullification was achieved using surface modification of CaCO 3 nanoparticles with triethoxy vinyl silane (TEVS) under controlled stirring. The sheets of iPP/PLA and iPP/PLA/nCaCO 3 were prepared at normal condition and subjected to a degradation study in minimal medium using P. chrysosporium microorganism up to 28 days. The growth of microorganism and fractures inside the polymer matrix before and after degradation was observed using a scanning electron microscope. Changes in extracellular protein content, biomass production, and percent degradation with respect to time of incubated samples have also been studied. It was found that the iPP/PLA/nCaCO 3 (5 phr) and iPP/PLA (at 30% PLA) composites show an increment in degradation. The presence of nCaCO 3 leads to faster degradation of iPP/PLA/nCaCO 3 nanocomposites, which decreases the mechanical property by 30% of PLA and 5 wt% of nCaCO 3 content. C 2016 Wiley Periodicals, Inc. Adv Polym Technol 201 , , 21691; View this article online at wileyonlinelibrary.com.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.