Nanotechnology

BACKGROUND:

Absorbable collagen sponge (ACS) loaded with bone morphogenetic protein-2 (BMP-2) is approved for selected clinical applications; however, burst release limits its widespread use. Therefore, nanofiber (NF)-based scaffold with ACS backbone was developed to sustain release of loaded BMP-2 to improve the outcomes of bone grafting in a rodent model of cleft palate.
METHODS:

BMP-2 was loaded on ACS scaffold and then NF hydrogel with different densities (1-2%) was added to sustain the BMP-2 release. The release profiles of BMP-2 from constructs with different NF densities were evaluated in vitro to explore the optimum NF density that could recapitulate physiological bone healing process. Subsequently, scaffold with the appropriate NF density was implanted into a rodent model of cleft palate. Wistar rats, with surgically induced maxillary cleft defects, were then assigned to one of the following groups (n=6/group): no scaffold (control), ACS, ACS+BMP-2, NF+ACS, and NF+ACS+BMP-2. Micro-computed tomography (μCT) was utilized to evaluate percent bone filling (%BF) at defect site as well as changes in anteroposterior and transverse dimensions of the maxilla at weeks 0, 4, and 8. Histological assessment of bone healing was performed at week 8.
RESULTS:

In vitro release experiments showed that scaffolds containing 2% NF exhibited a release profile conducive to the natural stages of bone healing and, hence, it was utilized for subsequent in vivo studies. Bone healing occurred at the defect margins leaving a central bone void in the control, ACS, and NF+ACS groups over the 8-week study period. BMP-2-treated groups demonstrated higher %BF as compared with other groups at week 8 (p<0.05). Whereas the NF+ACS+BMP-2 group showed bone bridging of the defect as early as 4 weeks, which was not evident in ACS+BMP-2 group. In all groups, bone grafts did not disrupt anteroposterior and transverse growth of maxilla. Based on histological evaluations together with μCT data, NF+ACS+BMP-2 treatment resulted in clinically significant and consistent bone healing throughout the implanted scaffold when compared with the ACS+BMP-2 group.
CONCLUSION:

NF+ACS+BMP-2 constructs exhibited osteoinductive properties together with preparation simplicity, which makes it a novel approach for BMP-2 delivery for cleft palate reconstruction.

Printed electronics and renewable energy technologies have shown a growing demand for scalable copper and copper precursor inks. An alternative copper precursor ink of copper nitrate hydroxide, Cu2(OH)3NO3, was aqueously synthesized under ambient conditions with copper nitrate and potassium hydroxide reagents. Films were deposited by screen-printing and subsequently processed with intense pulsed light. The Cu2(OH)3NO3 quickly transformed in less than 100 s using 40 (2 ms, 12.8 J cm–2) pulses into CuO. At higher energy densities, the sintering improved the bulk film quality. The direct formation of Cu from the Cu2(OH)3NO3 requires a reducing agent; therefore, fructose and glucose were added to the inks. Rather than oxidizing, the thermal decomposition of the sugars led to a reducing environment and direct conversion of the films into elemental copper. The chemical and physical transformations were studied with XRD, SEM, FTIR and UV–vis.

Electrophoresis deposition (EPD) was used for fabrication of TiO2 layer on the FTO glass substrate. Different chemical methods such as successive ion layer adsorption and reaction (SILAR), chemical bath deposition (CBD), microwave (MW) and hydrothermal (HT) were served to deposition of CdS on the prepared TiO2 surface. Also TiO2/CdS nanocomposite was synthesized by hydrothermal method and was then deposited on the FTO surface via doctor balde (DB) technique. The effect of deposition method on optical properties was investigated. The results showed that different deposition methods create different electrodes with various optical properties. The surfaces was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), cross-section SEM, UV-Vis diffuse reflectance spectroscopy (DRS), energy dispersive X-ray analysis (EDX) spectroscopy, atomic force microscopy (AFM), cyclic voltammetry (CV) and UV–vis spectroscopy. Dye-sensitized solar cells (DSSC) made by the fabricated electrodes as working electrode and then investigated by current density-voltage (J-V) curve and electrochemical impedance spectroscopic (EIS). It was found that deposition method has significant role in solar cell performance and efficiency.

In the current study, CdS/ZnS core–shell nanoparticles were successfully synthesized from CdSO4·8H2O and Zn(NO3)2·6H2O starting reagents in the presence of ultrasonic irradiation. The effects of preparation parameters such as ultrasonic power, irradiation time, and precursor concentration on the morphology of the CdS/ZnS core–shell nanoparticles and the removal of heavy metals (Hg+2, Pb+2) were studied by SEM and batch adsorption studies. The as-synthesized products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution field-emission transmission electron microscopy (HRTEM), photoluminescence spectroscopy (PL), scanning electronic microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and ultraviolet-visible (UV-Vis) spectroscopy.

Copper indium sulfide, CuInS2, nanocrystals were synthesized by a new precursor complex, [bis(2-hyroxyacetophenato)copper(ΙΙ)], [Cu(HAP)2], via a microwave method. The effects of sulfur sources, solvents, heating time and microwave power on morphology of product were investigated. The as-synthesized CuInS2 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible (UV–vis) spectroscopy, and room temperature photoluminescence (PL) spectroscopy. The nanoparticles of CuInS2 were used to prepare CuInS2 film by doctor's blade technique. The fill factor (FF), open circuit voltage (Voc), and short circuit current (Isc) were obtained by I–V characterization.

The 7500 SMM was used to measure Escherichia coli (E. coli) bacteria in air and in liquid using tapping mode for imaging soft materials. Quantitative SMM calibration is routinely achieved resulting in complex impedance images of bacteria in air including capacitance (aF; attoFarad) and conductance (μS; microSiemens) images. The calibrated capacitance images were compared to 3D microwave finite element modelling (FEM) using the EMPro software package for proper data interpretation. The SMM frequency response function was investigated experimentally and compared to the circuit model based on the simulation package ADS. Both EMPro and ADS modelling are used to gain insights into the sub-surface imaging capabilities of bacteria and cell compartments at different frequencies and different experimental conditions. The bio-SMM allows for quantitative and calibrated imaging of complex impedance at broadband frequencies between 1 kHz and 20 GHz.

We present a new method to extract resistivity and doping concentration of semiconductor materials from Scanning Microwave Microscopy (SMM) S11 reflection measurements. Using a three error parameters de-embedding workflow, the S11 raw data are converted into calibrated capacitance and resistance images where no calibration sample is required. The SMM capacitance and resistance values were measured at 18 GHz and ranged from 0 to 100 aF and from 0 to 1MΩ, respectively. A tip-sample analytical model that includes tip radius, microwave penetration skin depth, and semiconductor depletion layer width has been applied to extract resistivity and doping concentration from the calibrated SMM resistance. The method has been tested on two doped silicon samples and in both cases the resistivity and doping concentration are in quantitative agreement with the data-sheet values over a range of 10-3 Ω∙cm to 101 Ω∙cm, and 1014 atoms/cm3 to 1020 atoms/cm3, respectively. The measured dopant density values, with related uncertainties, are [1.1±0.6]x1018 atoms/cm3, [2.2±0.4]x1017 atoms/cm3, [4.5±0.2]x1016 atoms/cm3, [4.5±1.3]x1015 atoms/cm3, [4.5±1.7]x1014 atoms/cm3. The method does not require sample treatment like cleavage and cross-sectioning, and high contact imaging forces are not necessary, thus it is easily applicable to various semiconductor and materials science investigations.

The history of food production, ranging from agriculture to industrial processing, is briefly
surveyed. The potential contributions of nanotechnology, direct, indirect and conceptual,
are assessed, both in the short and long terms. Both technological and political challenges
are addressed.

Multiple spatial mapping techniques of biological tissues have been proposed over the years, but all present limitations either in terms of resolution, analytical capacity or invasiveness. Ren et al (2015 Nanotechnology 26 284001) propose in their most recent work the use of a picosecond infrared laser (PIRL) under conditions of ultrafast desorption by impulsive vibrational excitation (DIVE) to extract small amounts of cellular and molecular components, conserving their viability, structure and activity. The PIRL DIVE technique would then work as a nanobiopsy with minimal damage to the surrounding tissues, which could potentially be applied for high resolution local structural characterization of tissues in health and disease with the spatial limit determined by the laser focus.

As per the circuit complexity is increased there is a need of advancement of technology by using reversible logic. The circuit complexity comprises number of gate, size, power, delay and other parameters. Furthermore, error control methodology is required in reversible area which processes input, maintains data integrity, testing, error detection and checking the required output. The various approaches are categorized for error control which are significantly different and provides optimized solutions. In this paper, we design a various compact circuits related to error control schemes. Two 4x4 reversible series gates, namely inventive gate and inventive Parity preserving gate are introduced, to optimize the various error control circuits. We also introduced feasible methodology of concurrent error detection (CED), hamming single bit error correction (SBEC) and double bit error detection (DBED), 23×3 priority encoder circuit and dual rail checker circuit with parity- preserving behavior all with its detailed algorithm.

The use of plant products as nutritional food and therapeutic agents is immemorial and intimately linked to the human life since its origin. Also, the tanning action of plant extracts has been hugely exploited to transform animal skins into leather from ancient times to present. However, the exploitation of the potential applications of plant biomolecules in some of the modern technologies is rather now emerging. In fact, the power antioxidant, reducing and biological activities of the plant metabolites together their chelating and their biodegradable properties, make the plant-derived natural products unique raw materials to design new sustainable approaches to prepare promising hybrid formulations and composites at the nanometer scale for innovative diagnostic and therapeutic procedures and nanotechnology applications. In the present contribution, some recent advances and present challenges in this topic are briefly discussed.