Intravaginal use of natural micronised progesterone to prevent pre-term birth: a randomised trial in India.

In a prospective, randomised trial, 100 pregnant women with >/= one prior spontaneous pre-term birth were randomised into two groups. Group 1 women received 100 mg natural micronised progesterone intravaginally once daily from 20-24 weeks' gestation until 36 weeks. Group 2 women did not receive progesterone. Both groups were regularly supervised until delivery. Pre-term birth (<37 and <34 weeks) and other maternal, neonatal outcomes were primary and secondary outcomes, respectively. Chi-square test and Fisher exact test were used to compare categorical variables. Independent sample t-test and one-way ANOVA were used to compare continuous variables and multiple comparisons, respectively. Pre-term births <37 weeks were significantly lower in Group 1 (12% vs 38%, p = 0.002), but pre-term births <34 weeks were similar. The mean birth weight of neonates born to women in Group 1 was significantly higher (2800 vs 2,500 g, p = 0.023). We concluded intravaginal administration of 100 mg of natural micronised progesterone significantly reduced the incidence of pre-term birth <37 weeks in women with > or = one prior pre-term birth. Future research is warranted to assess the long-term safety and efficacy of progesterone.

Effect of phenol on the aggregation characteristics of an ethylene oxide-propylene oxide triblock copolymer P65 in aqueous solution.

The effects of phenol on the micellization, micellar growth, and phase separation of a poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO) amphiphilic copolymer (Pluronic P65: EO19 PO30 EO19) in aqueous solution have been studied by cloud point, viscosity, dynamic light scattering (DLS), differential scanning calorimetry (DSC), fluorescence spectroscopy, and small-angle neutron scattering (SANS). Various concentrations of P65 have been chosen to estimate the effect of phenol on different concentration regions of P65. Phenol interacts quite differently at low concentrations (0-2%) than at high concentrations (2-10%) of P65, as per the observation that phenol is more predominant at smaller concentrations of P65. A marked decrease in the cloud points of the P65 solutions is observed in presence of phenol. The critical micelle temperature (CMT) of P65 shows a synergistic effect of phenol on P65 aggregates. Micellar transitions, phase separation, and aggregation behaviours like micellization and micellar growth in the presence of phenol have been observed by combining viscometry, DLS, DSC, and CP. DLS shows that the effect of phenol is predominant at high temperatures. SANS shows a high increase in axial ratio and aggregation numbers in the presence of phenol at fixed concentrations of P65. Fluorescence data illustrate that addition of phenol makes micelles polar but at the same time its favours aggregation. Water-soluble phenol (present in low concentrations) forms aggregates with P65, which can be separated by cloud point extraction, making this study interesting for separation of phenol from the phenol-water system.

Microstructure and electrical properties of diborides modified by rapid thermal annealing.

Diborides of Ti, Hf and Zr are thermally, mechanically and chemically stable with good thermal and electrical conductivity. We tested their properties in front-end processes used in Si integrated circuits (IC). Films were deposited by e-beam evaporation either on Si, for the formation of contacts to the source/drain (S/D) regions, or on Si oxides, for the formation of metal gates in p-type metal-oxide-semiconductor (PMOS) transistors. We focused on their crystallization caused by rapid thermal processing (RTP) at temperatures up to 1100 degrees C. Transmission electron microscopy was used for identification of nanocrystallites of TiB(2), ZrB(2), and HfB(2). The grain growth was correlated with temperature and time of RTP. Of all borides, HfB(2) resulted in the most complete crystallization with little amorphous phase left. There was no crystallographic degradation of the interface with Si or dielectrics, except for extreme thermal budgets. Complementary techniques were used for monitoring chemical stability and electrical parameters of test structures to assess the role of recrystallization in device behaviour.

Concentration, temperature, and salt-induced micellization of a triblock copolymer Pluronic L64 in aqueous media.

The effect of copolymer concentration, temperature, and sodium halides (NaI, NaBr, NaCl, and NaF) on micellization and micellar properties of a poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO) amphiphilic copolymer (Pluronic L64: EO13PO30EO13), was examined by different methods such as dye spectral change, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), small angle neutron scattering (SANS), dynamic light scattering (DLS), viscosity, and cloud point (CP). Temperature/polymer concentration/salt dependent aggregation behavior of L64 was observed. The data on critical micelle concentration (CMC), critical micelle temperature (CMT), (CP), micelle size, and shape are reported. The Fourier transform infrared (FTIR) showed temperature dependent changes in C-O-C stretching variation band towards higher wave numbers and broadening of band width during the micellization process; this was attributed to increase in proportion of the anhydrous methyl groups, while the proportion of the hydrated methyl groups was decreased. Differential scanning calorimetry (DSC) provides CMTs and CPs from the same experiment. CMC values derived from dye spectral change, decrease significantly with the addition of salt. The increases in salt/copolymer concentration lower the onset temperature of micellization (CMT). Halide anions influence both CMT and CP in the order of F- > Cl- > Br- > I- when total salt and copolymer concentration kept constant. SANS results show the increase of inter-micellar interaction due to the increase in temperature/salt concentration; this is supported by viscosity data.

Effects of protein-polyelectrolyte affinity and polyelectrolyte molecular weight on dynamic properties of bovine serum albumin-poly(diallyldimethylammonium chloride) coacervates.

Bovine serum albumin (BSA) and poly(diallyldimethylammonium chloride) (PDADMAC) spontaneously form, over a range of ionic strength I and pH, dense fluids rich in both macroions. To study their nanostructure, these coacervates were prepared at low I and high pH (strong interaction) or at high I and lower pH (weaker interaction), with polymer MWs ranging from 90K to 700K, and then examined by dynamic light scattering (DLS) and rheology. DLS shows a dominant and surprisingly fast protein diffusional mode independent of polymer MW; accompanied by robust slow modes, slower by 1-2 orders of magnitude, which are also insensitive to MW and are present regardless of I, pH, and sample aging. High MW sensitivity was observed by rheology for the terminal time (order of milliseconds), which increased as well with the strength of polyelectrolyte-protein interaction. Viscoelastic behavior also indicated a tenuous network, solidlike at low strain but re-forming after breakage by shear. Two models, both of which have strengths and defects, are put forward: (I) macroion-rich domains dispersed in a continuum of macroion-poor domains near the percolation limit and (II) a semidilute solution of PDADMAC chains with interchain friction modulated by transient BSA-PDADMAC association.

Studies on surfactant-biopolymer interaction. I. Microcalorimetric investigation on the interaction of cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) with gelatin (Gn), lysozyme (Lz) and deoxyribonucleic acid (DNA).

The interaction of the surfactants cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) with the biopolymers gelatin (Gn), lysozyme (Lz) and deoxyribonucleic acid (DNA) was studied by isothermal titration microcalorimetry at varied biopolymer concentration, pH and temperature. The nature of interaction of the surfactants with the biopolymers was assessed from the observed enthalpy-[surfactant] profiles. The biopolymer-induced aggregation of the surfactants was observed. The enthalpies of aggregation of amphiphiles, binding of aggregates with macromolecules, organisational change of bound aggregates, and threshold concentrations for micelle formation of surfactants in the presence of biopolymers were estimated. The results collected on the three biopolymers were analysed and compared.

Physicochemical Investigations on the Interaction of Surfactants and Salts with Polyvinylpyrrolidone in Aqueous Medium.

Microcalorimetric investigations have been carried out onthe interaction of the surfactants sodium cholate, sodium deoxycholate, tetradecyltrimethylammonium bromide, cetyl(hexadecyl)trimethylammonium bromide, and p-tert-octylphenoxy polyoxy-ethylene ether (Triton X-100) and the salts potassium iodide, sodium benzoate, sodium bromide, and sodium salicylate with the neutral polymer polyvinylpyrrolidone (PVP). The enthalpy of dilution of the surfactants has been measured in the absence and presence of the polymer and the results are compared to determine the effect of PVP on the micellization of the surfactants and the energetics of the process. As well, the micellization activity of the surfactants in the presence of the polymer has been studied by conductometric and fluorimetric methods. The enthalpy of dilution of the salts has been measured to provide an understanding of the nature and magnitude of their interaction with PVP. Copyright 2001 Academic Press.

A simple chemical method for preparation of hydroxyapatite coatings on Ti6Al4V substrate.

A novel, simple and economical chemical bath method for deposition of calcium hydroxyapatite coating has been developed. The coatings were prepared from EDTA solutions in alkaline media on Ti6Al4V substrates. The method is based on thermal dissociation of the Ca(EDTA)2- complex at 65-95 degrees C. Two chemical baths with and without presence of Na+ and Cl- were used for the deposition. The Rutherford back scattering study shows that the coating material from bath which contained sodium and chlorine ions have their presence in the coated material. The bath which has been prepared with potassium substituting sodium and nitrate substituting chlorine produced coatings with better stoichiometry, with Ca/P=1,67. The X-ray analysis revealed that the calcium hydroxyapatite coatings have preferred crystal orientation in the 002 direction.