Is there a perfect protocol for patients with low ovarian reserve: a retrospective study comparing antagonist or agonist protocol in patients with low ovarian reserve

Background: The high prevalence of infertility has made it a major healthcare problem in the present era. A majority of patients presenting with infertility have poor ovarian reserve (POR). Patients with POR are challenging to treat due to reduced treatment success and high cycle cancellation rate as there is no uniform definition and treatment protocol for these patients. The present retrospective study was performed to compare the pregnancy outcome between a long agonist protocol and flexible antagonist protocol in patients with POR. Patients with AMH ≤1.5 ng/mL and AFC ≤4 was included in the study. Controlled ovarian hyperstimulation is the basis of any in vitro fertilisation (IVF) procedure. There is no universally accepted ideal stimulation protocol for patients with POR, and it remains a challenge.Methods: This was a retrospective study covering the period from May 2019 to March 2020. Ninety-nine patients with low ovarian reserve (AMH ≤1.5 ng/mL and AFC ≤4) were included in the study. The patients underwent GnRH agonist/GnRH antagonist stimulation protocol using recombinant FSH. Demographic characteristics like age, BMI, duration of infertility was comparable. Total days of stimulation, total Gonadotropin dose used and clinical pregnancy rate in both the protocols was analyzed. Difference between the two groups was considered statistically significant at p-value <0.05.Results: Fifty-three patients underwent antagonist stimulation protocol and forty-six long agonist protocol. The clinical pregnancy rate was 37.7% (20/53) and 32.6% (15/46) in antagonist and agonist protocol respectively (p-value=0.5983). Pregnancy rate was higher in the antagonist group but the difference was not statistically significant.Conclusions: Antagonist protocol could marginally increase pregnancy rate in patients with low ovarian reserve. However, patients with poor ovarian reserve require a tailor-made protocol

Large amplitude oscillatory shear rheology of three different shear-thickening particle dispersions

We present a large amplitude oscillatory shear rheology (LAOS) investigation of three different shear-thickening particle dispersions - fumed silica in polyethylene oxide (FLOC), fumed silica in polypropylene glycol (HydroC), and cornstarch in water (JAM). These systems shear-thicken by three different mechanisms - shear-induced formation of particle clusters flocculated by polymer bridging, hydrocluster formation, and jamming. The viscoelastic non-linearities of the three fluids were studied as a function of strain and strain-rate space through the use of Lissajous-Bowditch curves and local nonlinear viscoelastic moduli of an oscillatory shear cycle. The nonlinear behaviors of the three fluids were compared and contrasted to understand the nonlinear shear-thickening mechanism of each. Both HydroC and JAM dispersions were found to exhibit strong strain stiffening of the elastic moduli and strain thickening of the loss moduli behavior associated with possible hydrocluster formation and particle jamming. However, the FLOC dispersion, in contrast, showed strong strain softening and strain thinning behavior at large strain amplitudes associated with yielding of the microstructure. The expected thickening of the loss modulus of FLOC in LAOS with increasing strain was not observed even though viscosity of FLOC was found to shear-thicken in steady-shear measurements. This disagreement is likely due to very large strain amplitudes required for shear-thickening to occur by shear-induced polymer bridging mechanism. The hypothesis was confirmed through stress growth experiments. Conversely, the HydroC and JAM dispersions required relatively small applied strains for shear-thickening to occur by hydrocluster and jamming mechanism. The comparison of local intra-cycle nonlinearity through Lissajous-Bowditch plots and nonlinear viscoelastic parameters indicated that the elastic nonlinearities of all three systems are primarily driven by a strong dependence on the magnitude of the applied strain-rates within an oscillatory cycle rather than the amplitude of the applied strain. A close inspection of the LAOS data reveals strong differences in the viscoelastic nonlinearities of these three different shear-thickening dispersions which can be used to create a nonlinear rheological fingerprint for each and offers valuable new insights into the nonlinear dynamics associated with each of the shear-thickening mechanisms

High Power GaAs MMIC Chipsets for 18 to 32 GHz Frequency Band Applications

Recent commercial wireless applications such as Point to Point radio links, LMDS (Local Multipoint istribution Service), LMCS (Local multi-point Communications Service) and Commercial K-Band Satellite based services have spurred significant activity in development of mmWave power amplifiers. These applications lie in the frequency range of 18 to 42GHz with possible future extensions to 60GHz. These systems employ digital modulation schemes for which highly linear mmWave power amplifiers are essential. This paper presents an overview of some chipsets consisting of High Power amplifiers covering the frequency range of 18 to 32GHz. Preferred solutions to a low cost subsystem vary from one subsystem manufacturer to another as it involves assembly and test capabilities in addition to component costs. The overall direction appears to be toward multi-chip moduleassemblies. Here, both chip and packaged level component options are considered

High efficiency 1.4 W power amplifier for K-Band satellite communication system

A high efficiency 1.4 W MMIC power in the K-Band frequency band has been developed. A process technology optimized for high efficiency performance and an accurate design technique allowed us to achieve a power added efficiency of 42% with good noise power ratio figure. These performance make this device suitable for K-Band commercial satellite systems as part of antenna element array