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

Millets can have a major impact on improving iron status, hemoglobin level, and in reducing iron deficiency anemia– a systematic review and meta-analysis

The prevalence of iron deficiency anemia is highest among low and middle-income countries. Millets, including sorghum, are a traditional staple in many of these countries and are known to be rich in iron. However, a wide variation in the iron composition of millets has been reported, which needs to be understood in consonance with its bioavailability and roles in reducing anemia. This systematic review and meta-analysis were carried out to analyze the scientific evidence on the bioavailability of iron in different types of millets, processing, and the impact of millet-based food on iron status and anemia. The results indicated that iron levels in the millets used to study iron bioavailability (both in vivo and in vitro) and efficacy varied with the type and variety from 2 mg/100 g to 8 mg/100 g. However, not all the efficacy studies indicated the iron levels in the millets. There were 30 research studies, including 22 human interventions and 8 in vitro studies, included in the meta-analysis which all discussed various outcomes such as hemoglobin level, serum ferritin level, and absorbed iron. The studies included finger millet, pearl millet, teff and sorghum, or a mixture of millets. The results of 19 studies conducted on anaemic individuals showed that there was a significant (p < 0.01) increase in hemoglobin levels by 13.2% following regular consumption (21 days to 4.5 years) of millets either as a meal or drink compared with regular diets where there was only 2.7% increase. Seven studies on adolescents showed increases in hemoglobin levels from 10.8 ± 1.4 (moderate anemia) to 12.2 ± 1.5 g/dl (normal). Two studies conducted on humans demonstrated that consumption of a pearl millet-based meal significantly increased the bioavailable iron (p < 0.01), with the percentage of bioavailability being 7.5 ± 1.6, and provided bioavailable iron of 1 ± 0.4 mg. Four studies conducted on humans showed significant increases in ferritin level (p < 0.05) up to 54.7%. Eight in-vitro studies showed that traditional processing methods such as fermentation and germination can improve bioavailable iron significantly (p < 0.01) by 3.4 and 2.2 times and contributed to 143 and 95% of the physiological requirement of women, respectively. Overall, this study showed that millets can reduce iron deficiency anemia

Can feeding a millet-based diet improve the growth of children?—A systematic review and meta-analysis

Undernutrition, such as stunting and underweight, is a major public health concern, which requires multi-sectoral attention. Diet plays a key role in growth and should optimally supply all required nutrients to support the growth. While millets (defined broadly to include sorghum) are traditional foods, and climate smart nutritious crops, which are grown across Africa and Asia, they have not been mainstreamed like rice, wheat, and maize. Diversifying staples with millets can potentially provide more macro and micro nutrients, compared to the mainstream crops. However, there is little known scientific evidence to prove millets’ efficacy on growth. Therefore, a systematic review and meta-analysis was conducted to collate evidence of the benefits of millets in improving the growth of children. Eight eligible randomized feeding trials were included in the meta-analysis. Results from the randomized effect model showed a significant effect (p < 0.05) of millet-based diets on mean height (+28.2%) (n = 8), weight (n = 9) (+26%), mid upper arm circumference (n = 5) (+39%) and chest circumference (n = 5) (+37%) in comparison to regular rice-based diets over for the period of 3 months to 4.5 years, which was based on largely substituting rice with millets. When an enhanced and diverse diet was served, replacing rice with millet had only minimal growth improvement on chest circumference (p < 0.05). The quality assessment using GRADE shows that the evidence used for this systematic review and meta-analysis had moderate quality, based on eight scoring criteria. These results demonstrate the value of adding millet as the staple for undernourished communities. Further understanding of the efficacy of millets on growth in a wider range of diets is important to develop appropriate dietary programs and improve the nutritional status of various age groups across Africa and Asia

Does millet consumption contribute to raising blood hemoglobin levels compared to regular refined staples?: a systematic review and meta-analysis

Millets are recognized for their health and nutritional values, and the United Nations declared 2023 the International Year of Millets. Among the several health and nutritional benefits of millets, their impact on hemoglobin concentration is important since anemia is a major public health issue in many countries. To investigate the effect of millet (including sorghum) consumption on hemoglobin concentration in the blood, a systematic review and meta-analysis were conducted. Thirteen published studies featuring randomized control trials involving 590 individuals in the intervention group and 549 control individuals were eligible for the meta-analysis. The difference-in-differences analysis revealed highly significant (  < 0.01) positive effects of millet consumption on hemoglobin concentration, with an effect size of +0.68 standardized mean difference units. The change in hemoglobin concentration observed in the intervention group was +13.6%, which is statistically significant (  < 0.0005), compared to that in the control group, which was +4.8% and not statistically significant (  = 0.1362). In four studies, the consumption of millets in the intervention group demonstrated a change from mild anemia to normal status among children, whereas there was no change in the control group. The findings provide evidence that the consumption of millets can improve blood hemoglobin concentration, likely resulting from increased iron intake. Further research is needed involving the assessment of iron content and bioavailability to better understand the effect variation among millet types and the mechanisms involved

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 (λ = 583 nm) and 274 cm2 C−1 (λ = 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

A comparison of charge transport behavior in functionalized and non-functionalized poly 3,4-(ethylenedioxythiophene) films

Poly 3,4-(ethylenedioxythiophene) (PEDOT) films electropolymerized from an aqueous micellar solution containing sodium dioctyl sulfosuccinate and the monomer were functionalized with 1-fluoro-2-nitro-4-azidobenzene (FNAB) molecules by a photochemical nitrene insertion reaction. The variation in redox activity and the changes in the charge transfer and diffusion (through bulk) behavior of the functionalized and the non-functionalized PEDOT films have been followed by electrochemical impedance spectroscopy and cyclic voltammetry. While the functionalized film allows a reversible insertion and extraction of guest cations and anions, the non-functionalized film is capable of exchanging only anions. The higher level of oxidation attained in the functionalized film is also reflected in the longer diffusion length (lD) observed for the ions in this film. In both films the barrier to charge transfer is resistive rather than capacitive. Both charge transfer and diffusion resistance (RCT and RD) are lower for the functionalized film, a consequence of a higher surface roughness and a more nodular morphology and therefore higher optical contrast and faster color–bleach kinetics are achieved in this film. For the functionalized and the non-functionalized films, both RCT and RD are greatly enhanced during reduction than for oxidation. In particular, in the low frequency regime, the hindered diffusion-controlled extraction of anions from the bulk of the film is also evident from the larger RD as compared to RCT and the difference in their magnitudes is more pronounced for the functionalized film thus confirming that functionalization is a useful method for controlling the redox response of conducting polymer films

Poly(3,4-ethylenedioxythiophene) (PEDOT)- Coated MWCNTs Tethered to Conducting Substrates: Facile Electrochemistry and Enhanced Coloring Efficiency

Composite films of poly(3,4-ethylenedioxythiophene) (PEDOT)-coated over functionalized multiwalled coiled and linear carbon nanotubes (CNTs) have been fabricated by a simple oxidative electropolymerization route. The nanotubular morphology of the polymer-CNT composite is responsible for the lower charge transfer impedance, lower internal resistance, and superior capacitive response in comparison to that shown by the control PEDOT film doped by trifluoromethanesulfonate ions. This facile electrochemistry exhibited by the PEDOT-CNT composite film ensues in a remarkably high coloration efficiency of 367 cm(2) . C(-1) at 550 nm, hitherto unrealized for PEDOT; thus demonstrating the huge potential the PEDOT-CNT composite film has as cathode for the entire spectrum of electrochromic devices

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 cm2C1 at l=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

Charge Transport and Electrochromism in Novel Nanocomposite Films of Poly(3,4-ethylenedioxythiophene)-Au Nanoparticles-CdSe Quantum Dots

Nanocomposite films of Poly(3,4-ethylenedioxythiophene)-Au−CdSe have been fabricated for the first time by first growing a porous PEDOT layer in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and then introducing the film to a mixed colloid of Au nanoparticles (NPs) and CdSe quantum dots (QDs), thereby imparting a uniform confinement of Au NPs/CdSe QDs nanocomposite to the bulk of the polymer film by the virtue of affinity that Au has for the sulfur on the thiophene rings. Progressive luminescence quenching and absorption enhancement of CdSe QDs as a function of Au NPs incorporation in the CdSe colloid confirmed the direction of charge transfer from CdSe QDs to Au NPs. The optimized composition of Au−CdSe based on a maximum charge transfer was utilized for the formation of the nanocomposite with PEDOT. The loss of electrons from CdSe in the nanocomposite was also reflected in the core level signals of Se 3d corresponding to oxidized states of Se2+ and Se0. The charge propagation from CdSe to Au to PEDOT through Fermi-level equilibration was also confirmed by luminescence and absorption spectroscopy. The effect of Au−CdSe on electrochromic performance of the nanocomposite film was realized in terms of a superior optical density change, larger coloring efficiency (300 cm2 C−1, λ = 550 nm), and faster color-bleach kinetics when compared with the electroactivity of the control PEDOT film, grown without the inclusion of any nanomoiety