Exciting characteristic features of nanomaterials in contrast to their bulk phase require shape control of morphologies at the nanometer scale. Surfactants, a unique class of surface active ...molecules, possess remarkable ability to control crystal growth and direct it in shape and size controlled manner. The fine-tuning of the desired morphologies can be achieved by controlling the surfactant architecture as well as its self-assembly behavior. This review highlights the correlation between the surfactant properties and their ability in designing nanomorphologies. In terms of future perspectives, the methodologies can also be implemented to design biologically sustainable nanomaterials for their possible use in nanomedicine.
The role of self-assembled monolayers in electronic devices Singh, Mandeep; Kaur, Navpreet; Comini, Elisabetta
Journal of materials chemistry. C, Materials for optical and electronic devices,
01/2020, Letnik:
8, Številka:
12
Journal Article
Recenzirano
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Today, the self-assembled monolayer (SAM) approach for surface functionalization is regarded as highly versatile and compelling, especially in the immobilization of biomolecules and fabrication of ...novel supramolecular architectures. Most of the scientific articles recently published on biosensors use the concept of SAM to generate different surface functional groups for the immobilization of biomolecules such as antibodies, proteins, and enzymes. Due to the simplicity of the formation process and lack of requirement for costly instruments, this approach is prominent among researchers working in the field of surface functionalization and biosensing devices. Herein, we have reviewed a wide range of literature reports on electronic devices such as chemical sensors, biosensors and organic film transistors that use SAM concept for their purposes. In this review article, effort has been made to provide information about the SAM functionalization procedure,
i.e.
the technique used, the molarity of the SAM solution, and other physical/chemical conditions involved. Moreover, the fundamental concept of the monolayer, the types of monolayers on air/water interfaces, the techniques used for SAM formation on solid substrates and the use of SAMs for patterning are discussed.
Today, the self-assembled monolayer (SAM) approach for surface functionalization is regarded as highly versatile and compelling, especially in the immobilization of biomolecules and fabrication of novel supramolecular architectures.
A simple approach for growing porous electrochemically reduced graphene oxide (pErGO) networks on copper wire, modified with galvanostatically deposited copper foam is demonstrated. The as-prepared ...pErGO networks on the copper wire are directly used to fabricate solid-state supercapacitor. The pErGO-based supercapacitor can deliver a specific capacitance (C
) as high as 81±3 F g
at 0.5 A g
with polyvinyl alcohol/H
PO
gel electrolyte. The C
per unit length and area are calculated as 40.5 mF cm
and 283.5 mF cm
, respectively. The shape of the voltammogram retained up to high scan rate of 100 V s
. The pErGO-based supercapacitor device exhibits noticeably high charge-discharge cycling stability, with 94.5% C
retained even after 5000 cycles at 5 A g
. Nominal change in the specific capacitance, as well as the shape of the voltammogram, is observed at different bending angles of the device even after 5000 cycles. The highest energy density of 11.25 W h kg
and the highest power density of 5 kW kg
are also achieved with this device. The wire-based supercapacitor is scalable and highly flexible, which can be assembled with/without a flexible substrate in different geometries and bending angles for illustrating promising use in smart textile and wearable device.
The tensile test always delivers an in-depth understanding of true stress-strain relationship. However, it is not easy for the researchers to understand and evaluate the tensile properties of ...micro-specimens. This paper presents a research work aiming at the design and manufacturing of a small universal test machine (UTM) for measuring the mechanical properties of the miniaturised samples. The newly developed machine is sensitive to small loads and permits to obtain the stress-strain curves for thin materials. This portable UTM consists of a stepper motor, a load cell, a linear variable differential transformer (LVDT), a load cell amplifier and a data acquisition system. Copper based small and thin (50 μm) tensile test samples were tested on this machine at room temperature, and the calculated results were compared with the test results derived from a commercial UTM (METEX - 1 kN) to justify the validation of the developed apparatus. The obtained mechanical properties are in good agreement with the values obtained from a commercial UTM. To confirm the possibility of in-situ micro-observation, the surface roughness analysis has been conducted on the developed apparatus for pure copper foils under 3D laser-confocal microscope. Finally, it is concluded that this kind of testing apparatus could be manufactured within a manageable budget.
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The significance uses of Ka-Band and higher frequencies is due to high bandwidth demand from internet users, nevertheless, these high frequencies are susceptible to attenuation impairment dominantly ...due to rain. While the quality of received signal at consumer terminals (which is normally equipped with smaller antenna size) is important, the quality and availability of signal at earth station gateway is more important because the gateway serves the entire network of remote sites. If the signal at gateway is not available, the entire network will be affected. This paper presented the Ka-Band signal propagation data collected from MEASAT-5 satellite beacon tracking measurements for a period of 5 years. The data was collected at two gateway stations in Malaysia, Cyberjaya and Rawang, at 20.2 GHz frequency using 7.3 m diameter parabolic antenna. The antenna was located approximately 3 m above the ground with vertical polarization and with elevation angle of 68.8°. From the analysis of the rain intensity at the locations, Rawang experienced more intense rainfall which was an average of 85.2 mm/h than Cyberjaya which was 78 mm/h in average year from 2014 to 2018. The lower rain intensity, high elevation angle, vertical polarization and the high antenna gain configurations resulted in a reasonable attenuation at 0.01% of outage time which were 26 dB at Rawang and 17 dB at Cyberjaya. Therefore, it is observed that a low percentage of the Ka-band signal loss of over 0.01 percentage of time with reasonable attenuation can be achieved using the specified configuration.
Retinal cell therapy is envisioned as a treatment modality to repair the retina and improve vision in people with degenerative or hereditary retinopathies. In pursuit of this goal, transplantation of ...ES/iPS‐derived photoreceptor precursor cells is being developed as a treatment to replace lost photoreceptor cells. Several studies have shown that photoreceptor precursors can mature and incorporate into the recipient retina following transplantation in the subretinal space. However, knowledge regarding the identity and distribution of transplanted cells is incomplete, and furthermore, how closely the transplanted photoreceptors resemble normal photoreceptors in an intact wild‐type retina is unclear. In addition, a key gap in knowledge pertains to how the recipient retina regulates the maturation, fate specification, and migration of transplanted donor cells. This talk will describe how the subretinal space in the degenerative recipient eye promotes the maturation of transplanted rod and cone photoreceptor cells. In addition, observations of graft‐derived cells that migrate into the recipient retina, including some that travel long distances away from the graft, are presented. These findings highlight that in vitro human micro‐organogenesis can produce complex organoids with unusual and unexpected ectopic components that do not typically comprise the normal organ, and thus can profoundly influence therapeutic studies that use those organoids. These findings demonstrate the importance of the extracellular microenvironment in determining cell identity and behaviour in human organoids being developed for treatment purposes.
In this article, we propose SNG (single negative) metamaterial fabricated on Mg-Zn ferrite-based flexible microwave composites. Firstly, the flexible composites are synthesized by the sol-gel method ...having four different molecular compositions of Mg
Zn
Fe
O
which are denoted as Mg
, Mg
Mg
and Mg
. The structural, morphological, and microwave properties of the synthesized flexible composites are analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and conventional dielectric assessment kit (DAK) to justify their possible application as dielectric substrate at microwave frequency regime. Thus the average grain size is found from 20 to 24 nm, and the dielectric constants are 6.01, 5.10, 4.19, and 3.28, as well as loss tangents, are 0.002, 0.004, 0.006, and 0.008 for the prepared Mg-Zn ferrites, i.e., Mg
Mg
Mg
and Mg
respectively. Besides, the prepared low-cost Mg-Zn ferrite composites exhibit high flexibility and lightweight, which makes them a potential candidate as a metamaterial substrate. Furthermore, a single negative (SNG) metamaterial unit cell is fabricated on the prepared, flexible microwave composites, and their essential electromagnetic behaviors are observed. Very good effective medium ratios (EMR) vales are obtained from 14.65 to 18.47, which ensure the compactness of the fabricated prototypes with a physical dimension of 8 × 6.5 mm
Also, the proposed materials have shown better performances comparing with conventional FR4 and RO4533 materials, and they have covered S-, C-, X-, Ku-, and K-band of microwave frequency region. Thus, the prepared, flexible SNG metamaterials on Mg
Zn
Fe
O
composites are suitable for microwave and flexible technologies.
Target drug delivery methodology is becoming increasingly important to overcome the shortcomings of conventional drug delivery absorption method. It improves the action time with uniform distribution ...and poses minimum side effects, but is usually difficult to design to achieve the desire results. Economically favorable, environment friendly, multifunctional, and easy to design, hybrid nanomaterials have demonstrated their enormous potential as target drug delivery vehicles. A combination of both micelles and nanoparticles makes them fine target delivery vehicles in a variety of biological applications where precision is primarily required to achieve the desired results as in the case of cytotoxicity of cancer cells, chemotherapy, and computed tomography guided radiation therapy.
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•Micelles (structured reducing agents) as nanoreactors•Shape and size factors of nanoreactor micelles•Multifunctional block polymer micelle–Au NPs•Biodegradable block polymer micelle–Au NRs for chemotherapy•Block polymer micelle–Au NPs for computed tomography (CT) guided radiation therapy
The objective was to characterize the properties of cellulose nanofibril/TPS based nanocomposites. The cellulose nanofibrils were extracted from wheat straw using steam explosion, acidic treatment ...and high shear mechanical treatment. These nanofibrils were dispersed in thermo plastic starch (TPS) using a Fluko high shear mixer in varying proportions and films were casted out of these nanocomposites. The cellulose nanofibrils were characterized using AFM, TEM, SEM, TGA, FTIR and WAXRD and the nanocomposite films were analyzed in terms of SEM, WAXRD, TGA, DSC, mechanical and barrier properties. XRD and TGA results confirmed the crystalline nature of nanofibrils. AFM and TEM images revealed fiber diameter in the range 30–70
nm. TGA depicted an increasing in residue left with increase in cellulose nanofibrils content. Mechanical properties increased with nanofiber concentration. Barrier properties also improved with addition of nanofillers up to 10% but further addition deteriorated properties due to possible fiber agglomeration.
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