Is letrozole superior to clomiphene for ovarian stimulation prior to intrauterine insemination?

OBJECTIVE: To compare the efficacy of letrozole with clomiphene citrate for ovarian stimulation prior to intrauterine insemination. METHODS: A total of 272 patients underwent 362 cycles of stimulation prior to IUI from January 2009 to May 2011. One hundred and twenty-six patients (170 cycles) received letrozole 5 mg and 146 patients (192 cycles) received clomiphene citrate 100 mg for 5 days starting on day 3 of the cycle. Intrauterine insemination was done 36 ± 4 h after hCG injection in 99 patients (131 cycles) in the letrozole group and 115 patients (136 cycles) in the clomiphene group. The number of mature follicles and serum E2 levels was monitored on the day of hCG. Endometrial thickness was noted on the day of hCG and IUI as well. The pregnancy rate, the miscarriage rate, and other parameters were evaluated only for patients who underwent IUI. RESULTS: The mean number of mature follicles was significantly more in the clomiphene group (1.66 ± 1.69 vs. 1.41 ± 1.53) than in the letrozole group. No significant difference in endometrial thickness on the day of hCG administration was found; however, endometrial thickness was statistically significantly higher in the clomiphene group on the day of IUI (9.28 ± 1.43 vs. 8.77 ± 1.34). Serum E(2) levels on the day of hCG were statistically significantly higher in the clomiphene group (501.09 ± 2.45 vs. 214.79 ± 2.43 pg/ml). Pregnancy rate was 9.2 %/cycle and 12.12 %/patient in the letrozole group, and 8.1 %/cycle and 9.5 %/cycle in the clomiphene group; these differences were not statistically significant. CONCLUSION: This study found no superiority of letrozole over clomiphene when used for ovarian stimulation and IUI.

Influence of double hydrogen bonds and alkyl chains on the gelation of nonchiral polyurethane model compounds: sheets, eaves trough, tubes and oriented fibers.

We describe the gelation, upon self-assembly of a series of nonchiral molecules, resulting in tubular morphology of the fibers. These are biscarbamates, which are model compounds for polyurethanes with two hydrogen bonding groups separated by a (CH(2))(6) spacer and symmetrically substituted with alkyl chains on either side varying in length from C(6) to C(18). Upon gelation, these molecules form a sheet initially. The sheets then tend to wrap, leading to tubules. Those with partial wrapping resemble eaves troughs. With the predominant growth along the hydrogen bonding direction, the energy of interaction between the molecules along this direction would be more dominant than just the van der Waals interaction in the other two, leading to asymmetry of interaction in the sheet. We rationalize such tube formation in this case on the basis of the theories [Schnur, J. M.; Ratna, B. R.; Selinger, J. V.; Singh, A.; Jyothi, G.; Easwaran, K. R. K. Science, 1994, 264, 945. Schnur, J. M. Science, 1993, 262, 166. McKierman, R. L.; Heintz, A. M.; Hsu, S. L.; Gido, S. P.; Penelle, J. Polym. Mater. Sci. Eng. 2001, 84, 416.] which were developed for amphiphilic mono and bilayers, which state that these bilayers are not at their minimal energy when they are flat, and prefer a bent state. The gelation behavior of this series with double hydrogen bond is compared with the monocarbamates with a single hydrogen bonding motif [Moniruzzaman, M.; Sundararajan, P. R. Langmuir 2005, 21, 3802.]. We attribute the tendency toward both gelation and crystallization in some cases to the competing contributions of the hydrogen bond and van der Waals interactions between the long alkyl side chains. Oriented fibers for X-ray diffraction were obtained by simply using a magnetic stir bar during gelation. It is also found that the solvents that gel with diureas [van Esch, J.; Kellogg, R. M.; Feringa, B. L. Tetrahedron Lett. 1997, 38, 281] also form gels with biscarbamates. While the biscarbamates with even number of CH(2) groups in the side chain form short fibers, one with (CH(2))(9) side group formed long fibers characteristic of organo gels. In addition, when this odd side chain biscarbamate was mixed with one having a (CH(2))(8) side group, the gelation led to long fibers, following the sergeant and soldier principle.

Influence of single versus double hydrogen-bonding motif on the crystallization and morphology of self-assembling carbamates with alkyl side chains: model system for polyurethanes.

The difference in the morphology and crystallization aspects of hydrogen-bond-mediated self-assembling systems with single and double hydrogen-bonding motifs is studied here with carbamates as an example. These carbamates have alkyl side chains of various lengths, from C(4) to C(18). The biscarbamates with double hydrogen-bonding sites and symmetric substitution of alkyl segments show a significantly different morphological behavior as compared to the N-octadecyl carbamate alkyl esters (ref 5, referred to as simple carbamates henceforth) with a single hydrogen-bond motif and asymmetric substitution of alkyl side chains. In contrast to the simple carbamates in which no significant difference was found in the spherulite size from C(4) to C(12), with the biscarbamates we find that the spherulitic size, rate of growth of spherulites, and rate of crystallization show a maximum with an alkyl chain length of C(8). This is rationalized in terms of the relative contributions of the hydrogen-bond and van der Waals interaction energies. Oriented X-ray diffraction patterns from the fibrils of the spherulites lead to a model for the growth patterns of the hydrogen-bond planes and the molecular orientation in the spherulites.

Insecticidal activity of the plant Phyllanthus amarus against Tribolium castaneum.

The plant Phyllanthus amarus is used as folk medicine since the year 1800 and has been established for its important medicinal properties particularly for liver ailments. The present communication explores the insecticidal activity of ethanolic extract of aerial and root parts of this plant against stored grain pest Tribolium castaneum. LC 50 values of ethanolic aerial part were 895.77, 473.91, 279.89 and 260.85 microg/cm2, while 512.62, 376.96, 248.88 and 209.79 microg/cm2 for ethanolic root part at the exposure of 3, 5, 7, 9 and 11 days respectively. Ethanolic root extract possessed significant insecticidal activity against T. castaneum.