Comparative analysis of perinatal outcome of spontaneous pregnancy reduction and multifetal pregnancy reduction in triplet pregnancies conceived after assisted reproductive technique.

INTRODUCTION: With the advent of assisted reproductive treatment options, the incidence of multiple pregnancies has increased. Although the need for elective single embryo transfer is emphasized time and again, its uniform applicability in practice is yet a distant goal. In view of the fact that triplet and higher order pregnancies are associated with significant fetomaternal complications, the fetal reduction is a commonly used option in such cases. This retrospective study aims to compare the perinatal outcome in patients with triplet gestation who have undergone spontaneous fetal reduction (SFR) as against those in whom multifetal pregnancy reduction (MFPR) was done. MATERIALS AND METHODS: In the present study, eighty patients with triplet gestation at 6 weeks were considered. The patients underwent SFR or MFPR at or before 12-13 weeks and were divided into two groups (34 and 46), respectively. RESULTS: Our study found no statistical difference in perinatal outcome between the SFR and MFPR groups in terms of average gestational age at delivery, abortion rate, preterm delivery rate, and birth weight. The study shows that the risk of aborting all fetuses after SFR is three times (odds ratio [OR] = 3.600, 95% confidence interval [CI] = 0.2794-46.388) that of MFPR in subsequent 2 weeks. There were more chances of loss of extra fetus in SFR (23.5%) group than MFPR group (8.7%) (OR = 3.889, 95% CI = 1.030-14.680). As neither group offers any significant benefit from preterm delivery, multiple pregnancies continue to be responsible for preterm delivery despite fetal reduction. CONCLUSION: There appears to be some advantages of MFPR in perinatal outcome when compared to SFR, especially if the latter happens at advanced gestation. Therefore, although it is advisable to wait for SFR to occur, in patients with triplet gestation at 11-12 weeks, MFPR is a viable option to be considered.

Revelation of graphene-Au for direct write deposition and characterization.

Graphene nanosheets were prepared using a modified Hummer's method, and Au-graphene nanocomposites were fabricated by in situ reduction of a gold salt. The as-produced graphene was characterized by X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy (HR-TEM). In particular, the HR-TEM demonstrated the layered crystallites of graphene with fringe spacing of about 0.32 nm in individual sheets and the ultrafine facetted structure of about 20 to 50 nm of Au particles in graphene composite. Scanning helium ion microscopy (HIM) technique was employed to demonstrate direct write deposition on graphene by lettering with gaps down to 7 nm within the chamber of the microscope. Bare graphene and graphene-gold nanocomposites were further characterized in terms of their composition and optical and electrical properties.

Poly(3,4-ethylenedioxythiophene)-ionic liquid functionalized graphene/reduced graphene oxide nanostructures: improved conduction and electrochromism.

Nanocomposite assemblies of poly(3,4-ethylenedioxythiophene) (PEDOT), embedded with (a) fluoro alkyl phosphate based ionic liquid functionalized graphene (ILFG) and (b) reduced graphene oxide (RGO) prepared from a modified Hummers' method, have been synthesized. Defect free graphene nanosheets within the size of a few nanometers were achieved in the PEDOT-ILFG nanocomposite. In contrast, structures comprising graphene oxide wrinkles interspersed with the amorphous polymer were obtained in the PEDOT-RGO nanocomposite. X-ray photoelectron spectroscopy showed that neat ILFG was considerably less oxidized as compared to the neat RGO, which ratified the superiority of the ionic liquid functionalization strategy over the conventional chemical approach, for exfoliating graphite. Substantially higher electrochemical activity, improved ionic/electronic conductivity, much faster switching rates, and an almost ballistic enhancement in the electrochromic coloration efficiency attained for the PEDOT-ILFG nanocomposite in comparison to PEDOT-RGO film were irrefutable proofs that demonstrated the ability of the ionic liquid to not only fortify the structure of graphene but also facilitate charge transport through the bulk of the film, by providing less impeded pathways. Since PEDOT-ILFG/-RGO nanocomposites of good uniformity have been achieved, this, to some extent, addresses the challenge associated with the processing of graphene based high performance materials for practical applications.

A dual electrochrome of poly-(3,4-ethylenedioxythiophene) doped by N,N'-bis(3-sulfonatopropyl)-4-4'-bipyridinium--redox chemistry and electrochromism in flexible devices.

An electrochromic zwitterionic viologen, N,N'-bis(3-sulfonatopropyl)-4-4'-bipyridinium, has been used for the first time for doping poly (3,4-ethylenedioxythiopene) (PEDOT) films during electropolymerization. Slow and fast diffusional rates for the monomer at deposition potentials of +1.2 and +1.8 V, respectively yielded the viologen-doped PEDOT films with granular morphology and with dendrite-like shapes. The dual electrochrome formed at +1.8 V, showed enhanced coloration efficiency, larger electrochemical charge storage capacity, and superior redox activity in comparison to its analogue grown at +1.2 V, thus demonstrating the role of dendritic shapes in amplifying electrochromism. Flexible electrochromic devices fabricated with the viologen-doped PEDOT film grown at +1.8 V and Prussian blue with an ionic liquid-based gel electrolyte film showed reversible coloration between pale and dark purple with maximum coloration efficiency of 187 cm2C(-1) at lambda=693 nm. The diffusional impedance parameters and switching kinetics of the device showed the suitability of this dual electrochrome formed as a single layer for practical electrochromic cells.

Electrochemistry of poly(3,4-ethylenedioxythiophene)-polyaniline/ Prussian blue electrochromic devices containing an ionic liquid based gel electrolyte film.

Electrochromic devices based on poly(3,4-ethylenedioxythiophene) (PEDOT) as the cathodic coloring electrode and polyaniline (PANI) or Prussian blue (PB) as the counter electrode containing a highly conductive, self-supporting, distensible and transparent polymer-gel electrolyte film encapsulating an ionic liquid, 1-butyl-1-methylpyrrolidiniumbis-(trifluoromethylsulfonyl)imide, have been fabricated. Polarization, charge transfer and diffusion processes control the electrochemistry of the functional electrodes during coloration and bleaching and these phenomena differ when PEDOT and PANI/PB were employed alternately as working electrodes. While the electrochemical impedance response shows good similitude for PEDOT and PANI electrodes, the responses of PEDOT and PB were significantly different in the PEDOT-PB device, especially during reduction of PB, wherein the overall amplitude of the impedance response is enormous. Large values of the coloration efficiency maxima of 281 cm2 C(-1) (lambda = 583 nm) and 274 cm2 C(-1) (lambda = 602 nm), achieved at -1.0 and -1.5 V for the PEDOT PANI and PEDOT-PB devices have been correlated to the particularly low magnitude of charge transfer resistance and high polarization capacitance operative at the PEDOT ionic liquid based electrolyte interface at these dc potentials, thus allowing facile ion-transport and consequently resulting in enhanced absorption modulation. Moderately fast switching kinetics and the ability of these devices to sustain about 2500 cycles of clear-to-dark and dark-to-clear without incurring major losses in the optical contrast, along with the ease of construction of these cells in terms of high scalability and reproducibility of the synthetic procedure for fabrication of the electrochromic films and the ionic liquid based gel electrolyte film, are indicators of the promise these devices hold for practical applications like electrochromic windows and displays.

Poly(3,4-ethylenedioxythiophene)-multiwalled carbon nanotube composite films: structure-directed amplified electrochromic response and improved redox activity.

Composite thin films of poly(3,4-ethylenedioxythiophene) (PEDOT)-enwrapped functionalized multiwalled carbon nanotubes (MWCNTs) have been synthesized over multiple length scales by electropolymerization of the monomer without the use of any other supporting electrolyte. The functionalized MWCNTs are incorporated into the positively charged polymer deposit as counterions during oxidative electropolymerization. The morphology, electrochemistry, and electrochromism of the PEDOT-MWCNT films have been compared with those of control PEDOT films doped by triflate ions. Such a comparison enabled us to demonstrate the profound effect of MWCNTs as counterions, realized in terms of better electropolymerization rate, higher conductivity, faster color-bleach kinetics, higher charge storage capacity, and substantially amplified coloration efficiency (eta = 414 cm(2) C(-1), lambda(max) = 575 nm, E = -1.5 V) in comparison to the values of eta reported to date for PEDOT. The strong interaction between the polymer and MWCNTs, the interconnected nanotubular structures, and the porous framework of the film allow facile charge transport and larger ion uptake during redox switching. Electrochemical investigations on devices based on PEDOT-MWCNT and control PEDOT films established the practical utility of PEDOT-MWCNT films as they show lower charge-transfer resistance, higher diffusional capacitance, and a much smaller amplitude of impedance as compared to control PEDOT films.

Electrochromic contrast enhancement of nanostructured poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate films by composition/morphology control.

Poly(3,4-ethylenedioxythiophene) (PEDOT) films have been electropolymerized from an aqueous micellar polyethylene glycol (PEG) based solution containing sodium poly(styrenesulfonate) (NaPSS) and lithium trifluoromethanesulfonate. On varying the NaPSS content in the electrodeposition bath, two strikingly different nanostructured morphologies were obtained for ensuing PEDOT:PSS films and these have been correlated to the electrochemical and optical performance of the films. The films grown from the formulation with EDOT:NaPSS in a 1:3 weight ratio comprise of a nanoparticulate structure with a to date scarcely reported hexagonal structure. The film surface is also characterized by some unusual floral shapes encompassing elongated grains. TEM studies reveal that in the 1:3 film two dimensional (planar) PEDOT chains are stacked on top of each other with a vertical separation of 4.63 A. On the other hand the film generated from a 1:1 solution shows a texture wherein a random segregation of PSS particles is seen and this adversely affects the electrochromic response of the film. The larger charge storage capacity (4.9 mC cm(-2)), better charge reversibility during coloration and bleaching, good electrochemical cycling stability up to 2500 cycles, higher electronic conductivity and a superior coloration efficiency of 233 cm2 C(-1) at a photopic wavelength of 550 nm under ion intercalation levels of 0.058 to 1.2 mC cm(-2) shown by 1:3 film as compared to the performance of the 1:1 film are ramifications of fast ion movement promoted by the novel microstructure and the hexagonal modification which has rarely been achieved in PEDOT:PSS films.