Advanced Nano-Bio-Materals and Devices – AdvNanoBioMD 2022; Vol 6; Issue 4 (December 30)
In the present work powder morphology and kinetics of adsorption-desorption of water vapor on magnetite nanopowder prepared by chemical precipitation method from iron chlorides in the presence of hydrazine as well as its specific surface area and skeleton density have been investigated. It was established that synthesized magnetite nanopowder has a quite uniform particles size distribution and particles (33-84 nm) with a regular close to spherical shape. According to BET results synthesized magnetite (skeleton density 3.42±0.02 g/cm3) can be characterized as a microporous material with specific surface area, pore volume and average pore diameter equal to 28 m2/g, 0.01 cm3/g and 2 nm, respectively. The study of adsorption-desorption kinetics of water vapors on magnetite nanopowder showed that adsorption rate depends on humidity. At 100 % humidity adsorption rate stabilizes during 0.5-4.5 h and after maintaining powder at 100 % humidity for 24 hours the reduced adsorbed weight reached the value 0.42. It was shown that desorption process depends on the rate of temperature increasing. Thus, the desorption of adsorbed water ends after 24 min and 1 h at the rate of temperature increasing 5 °C/min and 1 °C/min, respectively. The most intensive desorption process take place in the range of 35–55 °C at 55 % humidity. Obtained results could be useful for magnetite nanopowder storage after synthesis and predicting the adsorption properties of composite based on it.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2022; Vol 6; Issue 1 (March 30)
The modern development of nanotechnology is marked by the emergence of various magnetic inorganic nanometer particles. They are widely used in various fields of science and have great potential in biomedical applications, including, for example, cancer therapy, drug nanocarriers or targeted delivery and diagnostic systems involving controlled nanoparticles such as nanoprobes and contrast agents. Significant efforts have been made by scientists to design iron oxide nanoparticles due to their superparamagnetic behavior and large surface area, which provides greater biocompatibility and easy binding to natural biomolecules. The article considers the typical characteristics and general methods of obtaining magnetite, as well as the main biomedical applications of magnetite nanoparticles.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2021; Vol 5; Issue 2 (June 30)
This paper presents a translation of the natural language into a chart flow for some viral invasions. The proposed model is suitable for those families of viruses who replicate inside the host cell nucleus. A logic circuits with finite state is based on an organizational-chart that is extracted from a natural language. Therefore, this initial step in logic circuits implementation, is applied to the life cycle of these particular viruses. The main scope is to establish clear states, input variable and output command functions. The viral invasion modeling might be interesting for the analysis of multi-omics data sets. Other applications of organizational chart could be in micro-biology or virusology, to offer algorithms for antiviral agents development.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2021; Vol 5; Issue 1 (March 30)
Recent technological developments have made researchers optimistic about the viability of wireless sensor network (WSN). On the other hand, the technological advancements across various domains have given momentum to realize the feasibility of cyber physical system (CPS) for various applications. The efficacy of the WSN-based application can be improved by intertwining the WSN and CPS. However, there exists multi-faceted challenges in WSN from the perspective of CPS for futuristic applications. This paper attempts to present a framework for wireless sensor network and cyber physical system (WSN-CPS). The various challenges are discussed in implementation of WSN-CPS. The unified framework of WSN-CPS envisages various comprehensive futuristic applications. Further, this paper describes medical applications of the wireless network sensors, in terms of convenient materials.
Advanced Nano-Bio-Materals and Devices – AdvNanoBioMD 2020; Vol 4; Issue 4 (December 30)
The age of porous materials started in 1992 along with the first synthesis of the MCM-41. During these ~ 30 years many synthesis routes were proposed and consequently, some characteristic mesoporous materials were developed and tested in many applications, including tissue engineering and drug delivery. This paper is highlighting the possibility to use mesoporous silica as platforms for the delivery of the antibiotics. It is based on a literature review of the drug delivery systems based on ordered mesoporous silica supports loaded with antibiotics and designed for the treatment of different infections. The manuscript is focused on the influence of pore size and surface functionalization on the final performances of these drug delivery systems being known that specific surface area and hydrophyl/hydrophobe ratio are among the most important factors influencing the interaction between the silica support and the antibiotic (drug).
Since February 2020 SARS-CoV-2 infected US and based on the statistics, the infection rates developed like a tsunami, affecting over 3% of US population, representing 20% of the world cases. The US CDC protection instructions were flimsy, incomplete and badly explained while virus transmission explanations were an affront to common sense that motivated us to develop protective devices to allow sitting in the presence of a contagious person and be safe, suppressing virus transmission. The development considers the transmission through direct contact and aerosolized watery droplet respiratory transmission that accounts for more than 80% of the cases. The further study showed that masks and social distancing were not enough to suppress transmission, and systems that are more complex are needed. Three patent applications were filed concerning individual protection using air restauration technologies, later developed into synergistic protective systems, and a set of furniture to allow dining and seating in close proximity, being protected by several confinement layers based on aerodynamics and energetic radiation able to sterilize and refurbish the air, making it better to breathe.
The patents come to mitigate the failures of society to protect itself in a smart manner, providing means to have the same social life and proximity as before 2019 and stay safe even in the presence of COVID-19 contagious specimens, preferable without shutting down or disturbing the economy and social life. A smart society should use the synergistic protective systems for at least 3 weeks may suppress any pandemic, if uses cellphone GPS-Wi-Fi tracking, border control and medicine.
This paper presents a conceptual Metal-Oxide-Semiconductor structure, but applied to biomimetic functions. The proposed structure is an alternative solution to the Nothing On Insulator (NOI) device. By a rotation of 900 the vertical NOI structure becomes a planar NOI structure, based on a beneficial oxide tunneling current through sub-10nm oxide. In this paper, this planar device is called planar-Nothing On Insulator (p-NOI) device. Its work principle is derived from the NOI concept, but the vacuum is replaced by oxide. Oxide has the same dielectric permittivity as myelin. The ionic charge in intra- or extra-cellular environment can be easily adapted by appropriate doping concentration in semiconductor. The ionic channels that cross the cellular membrane are placed at 500nm and allow the electric charge transport through membrane. Due to this analogy, a p-NOI biomimetic device is proposed to simulate the resting and action potential at a membrane level and the biosignal propagation through ionic channels. By simulations, the p-NOI device enables new functionalities as neuro-morphic device, mimicking the resting/action potential transmission over the bilipid membrane.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2020; Vol 4; Issue 3 (September 30)
Structure and properties of commercial Chitosan-50 powder ((C6H11NO4)n, M=500.000, Wako Pure Chemical Industries Ltd.) were investigated. XRD, IR spectroscopy, DTGA and SEM were used. It was shown that chitosan powder is characterized only by chitosan phase and flaky flat irregular particles and agglomerates sized from 5 nm to 200 μm. Decomposition of chitosan is complete at 580 °C. Specific surface area, which was measured by nitrogen adsorption-BET method, is equal to 0.80±0.01 m2/g and skeleton density, which was measured by helium pycnometery, is equal to 1.49±0.01 g/cm3. According to zeta potential investigation it was established that chitosan is characterized by electrostatic stability in ethanol and isopropanol and lack of electrostatic stability in water and acetone.
Glassy carbon electrode (GCE) has been modified by mechanical entrapment method with Polyaniline Nanoparticles / Graphene for developing a new nanosensor (PANINPs/GR/GCE). It was characterized by electrochemical analysis to evaluate it as a nano-sensor for analytical electrochemistry. A standard solution of 0.06 mM K4[Fe(CN)6] in 0.1M KCl was used as an electrolyte, in order to study the Fe(II) / Fe(III) redox current peaks at various concentrations, pH, scan rates, measurement of diffusion coefficient, stability and reliability on the modified electrode. It was found that the new modified electrode (PANINPs/GR/GCE) improved the oxidation-reduction current peaks of Fe(II)/Fe(III) ions at 25 oC from 6.71 to 23 µA and -5.14 to -17.5 µA, respectively. The current ratio anodic to cathodic current peaks was found Ipa/Ipc ≈ 1 of the new modified electrode with the potential peak separation of ∆Epa-c = 100 mV, which has shown a reversible and heterogeneous reaction of the new modified electrode in electrolyte. The new nanosensor has low detection limit, with good reliability and stability of nanoparticles on the GCE surface, and improved the oxidation-reduction current peaks in acidic medium.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2020; Vol 4; Issue 2 (June 30)
Breast is a rare location for Mycobacterium tuberculosis (MbT) infection. The paper analyses the first registered case with MBT location in a young Romanian women: a chronic primary TB breast abscess, non-pregnancy related, with periods of apparent healing and repeated areolar fistula formation. Incidence, risk factors, hypothetic mechanisms of primary / secondary breast MbT infection, microbiological assessment difficulties – related to conventional (smear with special stains as Ziehl Neelsen, and culture on specific solid/liquid media), immunological (proving host competence), and new methods (molecular tests as polymerase chain reaction, and the most advanced method with nanoparticles, delivering fast results, with high accuracy, sensibility, and specificity), the differentials to pyogenic abscesses, other chronic granulomas, and breast cancer, treatments issues are presented from the reviewed literature, focussing on breast location, and complications. One recalls the old concept of „therapeutic antitubercular” test, when all other available assessment steps are usefulness.
The purpose of the study was evaluation of the cytotoxicity of the Agrimoniae herba and Cichorii herba extracts by counting the metabolic activity and the viability of the isolated hepatocytes from the laboratory animals, MTT technique (3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide). Hepatocytes were extracted from the rats of the Wistar line according to the two-stage hepatocyte isolation protocol. Further, cytotoxicity and cell viability of the hepatocytes were determined in vitro after their exposure to the extracts obtained from Agrimoniae herba and Cichorii herba in concentrations of 100, 200, 600 and 1000 mg/ml. The cell viability of hepatocytes treated with the extract from Agrimoniae herba in doses of 100 and 200 mg/ml are 92.78 ± 1.75 % and 79.23 ± 1.49 % and for Cichorii herba in doses of 100 mg/ml and 200 mg/ml constituted respectively 92.07 ± 1.44% and 76.07 ± 1.61 towards the control group; the dose of the 600 mg/ml presents 77.27 ± 2.38% for Agromoniae herba and 57.23 ± 1.38 % for Cichorii herba respectively. The lowest cell viability was attained at the concentration of 1000 mg/ ml, representing 41.6 ± 1.98 % for Cichorii herba and 49.98 ± 3.53 % for Agrimoniae herba, considered to manifest the highest cytotoxic effect. Doses of 100-200 mg/ml obtained from Agrimoniae herba and Cichorii herba demonstrate cell viability and don’t affect hepatocytes, respectively can be used in further studies.
In the present work the effect of doping 1% nano-sized diamond particles on the structure and properties of biocomposites (sintered at 500 and 780 ºC on air) based on biogenic hydroxyapatite and sodium silicate glass were investigated. Volume and mass shrinkages of composites after sintering, their phase composition, microstructure, porosity, mechanical and bioactivity properties were studied. According to the XRD results it was established that sintering temperature and diamond doping does not effect on the phase composition of the biocomposites and only hydroxyapatite phase Ca5(PO4)6(OH) was detected. SEM investigation showed a complex morphology of samples surface and more rounded particles in agglomerates for biocomposites sintered at 500 ºC compared to biocomposites sintered at 780 ºC. The total porosity of the samples depends on the sintering temperature and the doping and is equal to 37-44 %. Experiments in vitro showed solubility of biocomposites in saline at 36.5±0.5 ºC and their mass loss in the first 2 days. Dissolution rate is equal to 0.42-0.78 wt.%/day depending on the sintering temperature and the doping of materials. It was found that doping nano-sized diamond 2 times increases the mechanical strength of biocomposites.
Some places are very sensitive to pandemic mass transmission, where a contagious person can easily infect over 50 persons in only 2 minutes of exposure. Facing this pandemic, infrastructure is prone to cascading if appropriate protection measures are not implemented in advance. The novel COVID-19 has some features that put it in the class of nano-bio-robot, and in the class of bio-warfare agents, where an accurate understanding on its propagation means is needed in order to design and implement the most appropriate protection measures. Leaders have to be aware how to increase protection in places where social distancing is difficult to achieve, and in places favoring accumulation of hazardous aerosols. As a compressible bio-nanoparticle with dimensions between 60-140 nm COVID-19 is not retained by normal dry filtration systems conceived for clean rooms, and special measures have to be taken to increase protection, and prevent virus reproduction rate bigger than 1. It is also stated that a single measure is not enough, as “social distancing” did not work well in the US, and an assembly of measures applied in harmony has to be set in place, in order to stop virus propagation. More medical studies are needed in order to better understand the virus, its propagation and consequences of getting infected, where the concept of heard immunity is just wishful thinking driving towards a crippled society.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2020; Vol 4; Issue 1 (January 31)
COVID-19 is a virus with its dimensions of about 100 nm when is in its spherical shape, had proven remarkable features as a nano-bot with displacement capabilities performed by spikes, a protein shield, and inside a genetic code, programmed to hack the cells and uses to reproduce itself. Duet to its shield and affinity for water it has proven a good immunity to environmental chemical agents, conferring it long survival time in air and surfaces. A very interesting feature is its affinity for human body, where it develops seamless, the human carrier becoming contagious well before realizing that is sick, and seek medical cure. Virus appeared in disputed circumstances in China, and in just 2 months spread on entire world, which was really unprepared and uneducated to face this entity, ending up with many causalities and a huge economic impact estimated at about ¼ GDP of most of the affected countries. From technological point of view, there are very limited ways to stop the virus and reduce the contamination, and a nano-technologic approach and understanding is needed to solve this problem that to guide social, behavioral and medical efforts both for seeking a cures and for individual protection.
Orange waste, a by-product of orange juice factories, has considerable amounts of phenolic and antioxidant compounds. In this research, the combination of Electrohydrodynamic (EHD) and enzymatic processes was examined to extract phenolic compounds from orange waste powder (OWP). To achieve this goal, the influence of pH (at 4, 4.5, 4.8, 5, 5.5 and 6 levels) and pectinase enzyme concentration (at 0, 0.5, 1, 1.5, 2 and 2.5% (w/w) levels) were examined on extraction of total phenolic compound (TPC) concentration, antioxidant activity (AA) of extracts, and the extraction efficiency (EE) from OWP. The results indicated that EHD process did not prevent the enzymatic activity of pectinase enzyme during extraction process. The highest amounts of TPC (617.76 ± 6.15 ppm), AA (87.50 ± 1.24%), and EE (68.00 ± 2.00%) parameters were obtained at pH of 4.8 and pectinase enzyme concentration of 1.5% (w/w). Furthermore, no significant differences in functional groups of the obtained OWP extracts were observed using Fourier Transform Infrared spectroscopy. Therefore, the results implied that the combined EHD- enzymatic extraction procedure could be considered as a novel and effective technique for the extraction of phenolic and antioxidant compounds from diverse resources especially from food processing wastes.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2019; Vol 3; Issue 4 (December 30)
The novel properties of nanomaterials also encourage their use to improve the growth of different tissues. Nano structured ceramics can be synthesized; thus, they may have particle size, geometry and microarchitecture similar to physiological bone. In this study, mechanical and bioactivity properties of nanohydroxyapatite (nHA)-nano magnesium oxide (nMgO) and nano hydroxyapatite (nHA) -nano niobium (V) oxide (nNb2O5) composites were compared. 80 wt.% nHA-20 wt.% MgO (nMH1), 70 wt.% nHA-30 wt.% MgO (nMH2), 80 wt.% nHA-20 wt.% Nb2O5 (nNH1) and 70 wt.% nHA-30 wt.% Nb2O5 (nNH2) nano composites including non-toxic binder were shaped by using press. The composites were sintered at 1000 and 1100°C for 2 hours, then microstructures, mechanical and bioactivity properties were determined. The physical and mechanical properties were determined by measuring density, firing shrinkage, compression strength and Vickers microhardness (HV). Structural characterization was carried out with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The bioactivity properties were determined after soaking the samples in the simulated body fluid. Density, compression strength and Vickers microhardness values of composites increased with increasing sintering temperature. The best density, compression strength and Vickers microhardness values were obtained with 70 wt.% nHA-30 wt.% MgO (nMH2) composite sintered at 1100°C as 3,16 g/cm3, 135 MPa and 438 HV, respectively.
In this work, we have investigated the self-assembled monolayer (SAM) of L-cysteine on Au(111) and its application in electrochemical oxidation of uric acid by scanning tunneling microscopy (STM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Monolayer of L-cysteine on Au(111) was observed, which shows that single monolayer of L-cysteine was formed on Au(111). Oxidation peak at 0.47 V was found for uric acid in 0.1 M HAc-NaAc buffer solution containing 2×10-5 M uric acid with pH=4.6 by CV, while two peaks can be observed for the solution with additional molecule of ascorbic acid. The influence of pH on electrochemical behavior of uric acid and ascorbic acid was also performed, which found that the peak distance and current is larger for pH=4.6 than that for pH=6. Those show that the solution with pH=4.6 may be good for the simultaneous detection of uric acid and ascorbic acid.
Nanometric particles and crystals play very important roles in biological systems. For example, calcium orthophosphates (abbreviated as CaPO4) of nanometric dimensions represent the basic inorganic building blocks of bones and teeth of mammals. According to recent discoveries in biomineralization, zillions nanometric crystals of biologically formed CaPO4 are nucleated in body fluids and, afterwards, they are self-assembled into these complex structures. In addition, both a greater viability and a better proliferation of various types of cells have been detected on smaller crystals of CaPO4. All these effects are due to a higher surface-to-volume ratio, an increased reactivity and biomimetic morphologies of the nanometric particles. Thus, the nanometric and nanocrystalline forms of CaPO4 appear to be natural for living organisms and, thus, they have a great potential to revolutionize the hard tissue-engineering field, starting from bone repair and augmentation to controlled drug delivery systems. Therefore, preparation and applications of nanometric CaPO4 are the important topics in modern biomaterial science and such formulations have been already tested clinically for various purposes. Currently, more efforts are focused on the possibility of combining nanometric CaPO4 with cells, drugs and/or other biologically active substances for multipurpose applications. This review describes current state of the art and recent developments on the subject, starting from synthesis and characterization to biomedical and clinical applications.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2019; Vol 3; Issue 3 (September 30)
In early 1980-s, researchers discovered self-setting calcium orthophosphate (CaPO4) formulations (initially known as calcium phosphate cements), which were bioactive and biodegradable grafting bioceramics in the form of a powder and a liquid. After mixing, both phases formed pastes of variable viscosity, which set and hardened forming most commonly a bone-like non-stoichiometric calcium deficient hydroxyapatite (CDHA) or brushite and rarely monetite with possible admixtures of un-reacted components. Since all these compounds were found to be biocompartible, bioresorbable and osteoconductive (therefore, in vivo they could be replaced with a newly forming bone), the self-setting CaPO4 formulations appeared to be very promising bioceramics for bone grafting purposes. Furthermore, due to their unique properties such as an easy shaping, moldability and injectability these formulations possess both an easy manipulation and a nearly perfect adaptation to the complex shapes of bone defects, followed by gradual bioresorption and new bone formation, which are additional distinctive advantages. Moreover, their low-temperature setting reactions and intrinsic porosity allow loading them by drugs, biomolecules and even cells for tissue engineering applications. However, due to the ceramic origin, the ordinary self-setting CaPO4 formulations exhibit both a brittle nature and a low bending/tensile strength, prohibiting their use in load-bearing sites; therefore, reinforced formulations have been introduced, which might be described as CaPO4 concretes. Thus, the discovery of self-setting properties opened up a new era in the medical application of CaPO4 and many commercial trademarks have been introduced as a result. Many more formulations are still in experimental stages. In this review, an insight into the self-setting CaPO4 formulations, as excellent bioceramics suitable for both dental and bone grafting applications, has been provided.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2019; Vol 3; Issue 2 (June 30)
The hyaline cartilage of the joint present high susceptibility to traumatic injury and degeneration and the ability of this tissue to regenerate is limited. Using a rabbit experimental model, our aim was to assess the Biomimetic scaffold capacity to recover the damaged cartilage by evaluation of Hounsfield Units (HU) on Computed Tomography scan. The biomimetic scaffold was represented by a monolit multi layered matrix. The superficial layer consists of type 1 equine collagen, the lowest layer consists of magnesium and hydroxyapatite and the middle layer consist of hydroxyapatite and collagen. The biomimetic scaffold promote bone and cartilage regeneration, by inducing selective differentiation of the body’s own bone marrow or synovial fluid derived progenitor cells into osteocytes, in the sub-chondral layer and chondrocytes in the cartilage layer. The HU of cartilage defect show higher values in the scaffold group compared with the control group at every time. Macroscopic and histological examination show regeneration of the chondral defect and formation of new hyaline-like tissue present only in the scaffold group.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2018; Vol 2; Issue 4 (December 30)
Additive manufacturing techniques like robocasting have a great potential for the fabrication of scaffolds for bone regeneration and tissue engineering. The goal of this study was to produce undoped and ion (Sr2+ and Mg2+) doped biphasic calcium phosphate (BCP) scaffolds by robocasting. The powders were prepared by hydrothermal synthesis (150ºC, 4 h), calcined at 1000ºC, and then deagglomerated to get an appropriate particle size distribution (PSD). High solid loading aqueous suspensions were then prepared from the milled powders and their rheological properties were optimized to confer them the desired viscoelastic properties for 3D printing. Porous scaffolds with different pore dimensions (300 x 300; 500 x 500; 250 x 500 and 300 x 600 µm) were fabricated by depositing paste filaments with 410 µm diameter according to previously defined CAD models. The green scaffolds were firstly dried and then the organic additives were removed by a heat treatment at 600ºC. Sintering was carried out at 1100ºC. The compressive strength of the scaffolds was within the range of the cancellous bone mechanical properties, being intrinsically related with the size of macro- and micro-pores. In addition, all the scaffolds compositions exhibited good in vitro bio-mineralization capacity. Overall, the obtained scaffolds revealed attractive properties for their application in bone tissue engineering.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2018; Vol 2; Issue 3 (September 30)
Hip arthroplasty consists of a series of sequential manipulations, one of them is the femoral neck osteotomy. The position of the implant and the presence of postoperative complications depend on accuracy of this technique implementation. The purpose of the study was to develop a device for the femoral neck osteotomy. The study was designed to investigate the accuracy of the femoral neck osteotomy with use of the developed device. The operational model of the device has been developed. The pilot studies on plastic bones models both in control group and group of comparison were conducted on the basis of Traumatology and Orthopedics Department Voronezh Burdenko State Medical University. The study data demonstrated a higher accuracy of the femoral neck osteotomy in the comparison group. The use of the developed device allows to perform the femoral neck osteotomy with high accuracy, and it also allows to control position of an implant. It can reduce the number of complications and improve the quality of patients’ lives.
The work is devoted to comparative investigation of the structure and adsorption properties of biogenic hydroxyapatite obtained by annealing cattle bones at 800 °С and two types of synthetic hydroxyapatite obtained by chemical precipitation followed by structuring with using carbon nanotubes for one of the powders and drying at 300°С. According to XRD and IR spectroscopy results, for all the studied powder, the presence of crystalline hydroxyapatite was proved. It was established that the morphology of particles and the specific surface area are different for different types of hydroxyapatite (synthetic hydroxyapatite are characterized by formation of a bigger number of large agglomerates in comparison with biogenic hydroxyapatite), whereas the adsorption activity does not depend on the hydroxyapatite origin and is equal to 106-108 mg/g. In the case of synthetic hydroxyapatite, it is provided by developed specific surface area (69.6-70.0 m2/g) of the powder, whereas in the case of biogenic hydroxyapatite, it is associated with a small size of most agglomerates.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2018; Vol 2; Issue 2 (June 30)
In this work, Polycaprolactone (PCL), silver nitrate (AgNO3) and zinc oxide (ZnO) were used for fabrication of a multilayered antibacterial nanocomposite material using co-axial electrospinning (CAE). 5, 10, and 15 wt. % concentrations of PCL were utilized, and varying amounts of AgNO3/ZnO were used in all samples to increase antibacterial activity. Products were analysed using Scanning Electron Microscopy (SEM) to obtain the morphological characterization, and Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the functional groups of the PCL, AgNO3, and ZnO materials in the electrospun nanocomposites. Tensile strength was also determined for each sample. Additionally, viscosity, density, and electrical conductivity were measured for each prepared solution before the CAE process. The antibacterial activity of the fabricated electrospun nanocomposite materials was tested against Staphylococcus aureus and Eschericha coli strains. A simple nanoscale assembly approach was provided using CAE processing to incorporate a variety of AgNO3 and ZnO functionalities into the nanoﬁbers to fabricate biohybrid materials for antibacterial surface applications.
Lipase is an enzyme that catalyzes the hydrolysis of fats (lipids) which was synthesized by bacteria in the lab and characterizes using electrochemical analysis by cyclic voltammetry method to find the effect of synthesis lipase in blood medium. It was found oxidation current peak of commercial lipase in blood medium at 0.5 V on glassy carbon electrode versus Ag/AgCl as reference electrodes and scan rate 0.1 Vsec-1, while the oxidation peak of synthesis lipase by bacteria was disappeared in blood medium. So, the synthetic lipase is advisable to be used as a safety enzyme to hydrolyze the lipids in human body avoiding precipitate of cholesterol molecules in blood vessels without any side effect.
The paper depicts some advanced technologies in order to install a low power consumption and reconfigurable sensor networks, which presents optimal operation and excellent reliability. The results of this paper are prepared during a research project that implements a low power microsystem in package so that the antenna and the radio interface are co-integrated. Consequently, the used instrumentation is designed for small distances, in order to be able to work in restricted areas as space and non-planar zones. A key requirement for the communicating node, which are acted by the sensors network, is to propose a flexible technology able to integrate the CMOS transceiver by Flip Chip onto an organic substrate. For this purpose, the antenna was directly implemented onto a flexible polymer material. The organic substrate selection must be performed in agreement to the radiation diagram of the antenna. As a second aim of this paper, an Organic Thin Film Transistor with pentacene film is simulated to capture the static characteristics and to find the matching parameters for other organic materials. In this scope, an alternative polymer grafted on nano-core material synthesis, is depicted.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2018; Vol 2; Issue 1 (March 30)
In this article are presented the results of 113 women of reproductive age study. The control group included 45 healthy women (the age range 22-47 years) who had no urogenital, endocrine system diseases or surgical inter-vention, no earlier than 9 months after the last birth and at least 3 months of regular menstrual cycles. The main group: 68 patients (the age range 24-48 years) suffering from secondary infertility, who subsequently as a result of an in-depth study found a tuberculosis lesion of the uterus. The main criteria for diagnosis were three times sowing of menstrual blood during one menstruation for bacteriological examination for the presence of my-cobacterium tuberculosis, bacterioscopic and bacteriological examination of the secretion of the cervix on the microflora and mycobacterium tubercu-losis. The aim of the study was to study the value of ultrasonic elas-tography with a shear wave elastography (SWE) in tuberculosis lesions of the uterus at patients with secondary infertility. Complex ultrasound studies of the uterus and appendages using the ultrasound elastography and SWE were performed on the Aixplorer (Supersonic Imagine, France). Based on the data obtained by us using the technology of elastography and SWE, stiffness values for unchanged endometrium, uterine myometrium in healthy women of reproductive age are established. The significant differences in the stiffness of the endometrium and myometrium of the uterus body of healthy women of reproductive age and patients with tuberculosis lesion of the uterus, revealed by us, indicate the expediency of using SWE with elas-tometry in the study of patients suffering from secondary infertility.
Different artificial sweeteners were studied in blood medium as electrolyte by cyclic voltammetric technique using modified glassy carbon electrode with carbon nanotubes to determine the diffusion coefficient for the redox current peaks of artificial sweetener by Randles-Sevcik equation. It was determined the viscosity of the blood medium after the addition of the artificial sweetener to find the relationship between the viscosity and the diffusion of sweetener ions in blood medium and reach to the electrode. The high viscosity of blood and addition of the sweetener compound which causes impedes of diffusion the ions for redox current of the reaction on the surface of the sensor. So, the results of diffusion coefficient values depended on the viscosity of blood medium. Sorbitol compound has a higher viscosity in blood medium with lower diffusion coefficient values of redox current peaks and mannitol has lower viscosity in the series of the sweetener compounds in blood medium with high values of diffusion coefficient for the redox current peaks.
Gold coated mesoporous silica magnetic nanocomposite (mSiO2@Fe3O4 @Au) was synthesized using ethylene glycol (EG) as template at two different ratios of EG: TEOS of 0.1 and 0.6. The chemistry, morphology, optical and magnetic properties of the obtained nanocomposites were characterized by Fourier Transform (FTIR), Scanning Electron Microscopy (SEM), Transverse Electron Microscopy (TEM), Atomic Force Microscopy (AFM), X-ray Diffractometry (XRD), Vibrating Sample Magnetometry (VSM) and UV-Vis absorption spectroscopy. The mean diameter of amino-functionalized SiO2 NPs was measured 70 nm. The range of porosity ranged from 10 to 100 nm, with larger distribution of pore size of less than 20 nm. The average radius of pores on SiO2 NPs calculated by BJH method is approximately 15.5 nm. Magnetic nanoparticles (MNPs) with the average diameter of 34 nm were synthesized and then coated by AuNPs with an average size of 25 nm synthesized via a two-step process of dative and reduction method. The average size distribution of mSiO2@Fe3O4@Au nanocomposite was measured about 157 nm. The nanocomposite exhibited a significant red-shift in surface plasmon resonance wavelength (λSPR ≈ 800 nm), which coincides with NIR biomedical applications.
Highly-porous ceramics samples based on nanostructured biogenic hydroxyapatite and superfine fumed silica have been prepared using a foam replication method at a sintering temperature of 850°С. They were shown to possess a total porosity 86-89 % and a permeable open-porous (~ 90 % of the total porosity) structure with pore sizes in the range 500-1000 μm. The compression strength is equal to 0.3-0.4 МPа. According to the XRD analysis it was established that during sintering hydroxyapatite phase remains, which was also confirmed by IR spectroscopy data. The carried out studies in vitro (the dissolution rate in saline) of the obtained highly-porous bioceramics showed that the samples are resorbable and their dissolution rate increases with growing porosity and decreasing HA content. Evaluation of adsorption activity (by the example of antibiotic Ceftriaxon) demonstrated prospectivity of ceramics as carriers of drugs for acceleration of patients’ post surgery rehabilitation in orthopedic, traumatic and dentistry surgery.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2017; Vol 1; Issue 4 (December 30)
This study aimed to develop a sustained-releasing asiaticoside-loaded liposome with well lung-targeting. Liposomes were prepared by film-dispersion and extrusion method. The rotatable central composite design (RCCD) with three-factor and five-level were applied to evaluate the optimization experiments. To maximize the percentage encapsulation efficiency (EE) and drug loading, a quadratic polynomial model was generated to predict and evaluate the independent variables with respect to the dependent variables. Fitting RCCD model were confirmed by the ANOVA Table (P<0.05) through variance analysis, which predicted values of EE (%) and drug loading in good agreement with experimental values. By solving the regression equation and analyzing the response surface, the optimal result for the preparation of D-mannose modified asiaticoside-loaded liposomes, three-dimensional model graphs and plots, were found as follows: the ratio of drug to lipid is 0.07;the ratio of cholesterol to drug is 0.17;and the content of D-mannose is 0.03 g·ml-1. The encapsulation efficiency was 75.529±1.071 % (n=3), the drug loading was 2.539±0.029% (n=3) and the deviation from the predicted values were -0.217% and 0.205%，respectively. The release profiles, pharmacokinetic behaviors and tissue uptake were performed. The results indicated that the asiaticoside loaded in liposomes could have slow and well-controlled release, and half-life increased obviously in vivo. Meanwhile, the asiaticoside would focus on the lung when the octadecylamine was conjugated on the surface of liposomes.
ENFETs are field-effect transistors integrated in the same chip with their recognition enzymatic elements, applied to bio-molecules detection like urea, creatinine, glucose, pesticides and so on. Despites to the recent developments, the concept of the ENFET designing is pretty complex and challenging, requiring microelectronics, electro-chemistry and bio-recognitions knowledge. Therefore, this paper presents some punctual advances in the field of Field Effect Transistor design part, aided by specific software from microelectronics, besides to some specific technological steps encountered to the enzymatic layer immobilization on nanostructured materials on Si-wafers.
Here, the Baicalin-loaded PLGA microspheres (BC-MS) were prepared, and their properties in vitro and in vivo were evaluated. The microspheres were prepared using the solvent evaporation method based on O/W emulsion. The HPLC method was established in the determination of the content of baicalin in the microspheres. The surface and particle size were observed by the inverted microscopy, and the characteristics of in vitro release of BC-MS were investigated by dynamic dialysis method. After that, the microspheres were in vivo evaluated in rats. It was observed that the microspheres had an average particle size of 1.89μm, the drug loading was 12.79%, and the encapsulation rate was 85.40%. Moreover, the microspheres were spherical in shape and smooth surface with a uniform distribution. The release profiles of BC-MS agreed with Ritger-Peppas equation. The plasma concentration-time curves of BC-MS were fitted with two-compartment model. The results of pharmacodynamics in rats showed that: the elimination half-life of baicalin solution (BC-S) and Baicalin-loaded PLGA microspheres (BC-MS) were respectively 1.27 h and 258.98 h, mean residence time (MRT) were 0.88 h and 373.01 h, respectively. As the above result shows, BC-MS has the slow-release effect. Thus, the Baicalin-loaded PLGA microspheres have been successfully prepared.
This work reports on successful one pot surfactant free in-situ synthesis of cobalt doped ZnO-chemically converted graphene (CCG) nanocomposite (CZG) by adopting a low temperature solution process utilizing zinc acetate dihydrate and graphene oxide with varying content of cobalt acetate tetrahydrate (upto 10% Co with respect to Zn) in the precursor medium. The materials properties were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), FTIR and Raman spectral analyses. The presence of ZnO nanoparticles (NPs) in the nanocomposites was confirmed by XRD and TEM studies. The TEM study revealed the uniform distribution of hexagonal ZnO in the CCG matrix. The existence of chemical interaction / complexation between CCG with ZnO/Zn2+ of the samples was confirmed by FTIR and Raman spectral analyses. The antibacterial activity was measured on Escherichia coli and Staphylococcus aureus as water borne bacteria to examine the efficiency of the nanocomposite towards killing the bacterial cells. Among the nanocomposites, 5% Co doped sample showed best antibacterial activity against the microorganisms. This synthesis strategy could open an avenue of Co doped other metal oxide-CCG nanocomposites for biomedical applications.
In this work, the effect of sonication on the size, morphology, and stability of gold nanostars was investigated for the first time. It was found that the seed-mediated method, followed by the sonication treatment developed in this study, offers new opportunities to synthesize aqueous suspensions of monodispersed gold nanostars with prolonged stability. The results indicate that at a sonication frequency of 25 kHz, the maximum average nanostar size of 120nm is attained. Increasing the sonication frequency, the average size of nanostars decreased significantly and, consequently, the position of the Localized Surface Plasmon Resonance (LSPR) band, could be easily tuned. It is thought that the change in the morphology is due to the collapse of the cavitation bubble which generates extreme conditions of pressure and temperature. Cavitation images in the gold nanostars solution were for the first time extracted by using an original software. It is found that the gold nanostars, after ultrasound treatment, are substantially more stable because their aggregation becomes much slower. The use of the sonication technique to stabilize gold nanostars, without any additional chemical stabilizer, is both technologically and scientifically important. It can be expected that by using this technique, to be able to produce large volumes of consistent quality, stable gold nanostars.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2017; Vol 1; Issue 3 (September 30)
Copper nanoparticles have been synthesized by the reduction of copper ions using plant leaf extracts of khat (Catha edulis), castor oil (Ricimus communis) and derjihara (Prosopis juliflora) as reducing and stabilizing agents. The progress of bio-reduction of Cu2+ ions generating metallic copper was monitored by observing the absorption peak around 566 nm, characteristic of surface plasma resonance of copper. The X-ray diffraction (XRD) analysis revealed the face centre cubic (fcc) crystal structure of synthesized copper nanoparticles with average crystallite size within 20 to 30nm. The FTIR spectra suggests that copper nanoparticles are stabilized possibly by proteins molecules present in the leaf extract. The synthesized copper nanoparticles have shown anti-microbial activity against both gram-negative, Escherichia coli, as well as gram-positive, Staphylococcus aureus bacteria. The synthesized copper nanoparticles may be tried, clinically, for their antibacterial, cytotoxic, and antibiofilm efficacy or may be used as copper nanoparticles-containing antimicrobial hydrogel membrane for the treatment of wounds.
Porous ferroscaffolds have interesting applications in bioengineering such as tissue engineering, controlled drug release and bioimaging. In this work, the conjugated fluorescein isothiocyanate (FITC) magnetite (Fe3O4) nanoparticles (FMNP) were embedded in the hydrogel scaffold (FFS) to study the effect of static magnetic field on swelling for drug release purpose as well as to serve as an optical marker to monitor visually the swelling of FFS for bioimaging. FFS was characterized using transmission electron microscopy (TEM), x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), vibration scanning magnetometry (VSM), UV-VIS absorption spectroscopy and laser-induced fluorescence spectroscopy (LIFS). The LIF exhibited a loss of fluorescence intensity of about 11% and 18% corresponding to laser irradiation time of 10 and 30 s respectively due to quencher fluorescent molecule complex formation. The magnetoelasticity of FFS was studied using He-Ne laser probe beam-magnet experiment. The swelling factor was found to be relatively small, nonetheless it was visually observable due to argon laser-induced fluorescence.
For many people, learning about new things such as a second language is an adventure and very fulfilling. Dopamine levels boost in the brain to help us maintain the new information. However, if dopamine levels are low, the new information literally goes in and out of the brain and is lost. This work postulates disability modeling function of dopamine as a neurochemical transporter in the brain for learning language after adsorption on Boron Nitride (BN) and Titanium dioxide (TiO2 Anatase) surfaces through the theoretical methods. Thermodynamic data and vibrations can identify modes of dopamine by comparison between dopamine-Boron Nitride and dopamine-TiO2 clusters.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2017; Vol 1; Issue 2 (June 30)
The main advantage of optoacoustic imaging (OAI) is the capability to detect diseases at their early stages of growth. The efficiency of this technique has been demonstrated by preliminary studies with real biological tissues and small animals. The definitive goal of in-vivo OAI is to provide maps of the absolute concentration of chromophores with the help of exogenous optical contrast agents. Usually, solid-state lasers are used for the generation of ultrasounds but their use in clinical environment is inconvenient due to their large sizes, high costs, and low repetition rates (a few Hz) that are not sufficient for a high resolution during image processing. However, the requirements of high repetition rates (up a few kHz) can be fulfilled by high-power diode lasers (HPDLs) combined in side-by-side arrays. In the present paper, we implement a three-wavelength optoacoustic (OA) system consisting on a small array of HPDLs and a diode laser bar (DLB) operating at 870 nm, 905 nm, and 972 nm, respectively, coupled to a 1.2-mm diameter optical fiber bundle. The combined beam illuminates different mixtures of two gold nanorods solutions with absorbance peak at ~ 860 nm and ~ 900 nm, respectively, to generate OA signals. The pulses produced to generate OA signals are alternated between the three wavelengths by a microcontroller circuit with fast switching (0.33 ms). An inverse algorithm is implemented to estimate the concentrations of the nanoparticles solutions from the amplitude of the OA signals. The results achieved with our system show good agreement between the concentrations of gold nanorods estimated from measurements and the expected values.
A customized optical system composed of collimating and focusing lenses is proposed to achieve the beam focusing of high-brightness diode laser bars with high fill factor for optoacoustic applications. Through an optimized design, the beam of a 940-nm diode laser bar is first collimated and symmetrized between the fast and slow axes, and then is reduced in size into a square beam (~ 3.7 mm x 3.7 mm at 1/e2 of the peak) with intensity of ~ 3.2 kW/cm2. In an optoacoustic environment, the optical spot achieved can illuminate a small region of tissue at high intensity to achieve in-depth imaging with high resolution.
The purpose of this study was to prepare and to characterize a new formulation of injectable capsaicin loaded poly (D,L-lactic-co-glycolic acid) (PLGA) microspheres (CAP-MS). The emulsion solvent evaporation process based on O/W emulsion was applied to prepared the CAP-MS with optimization of formulation using uniform design with three factors and six levels. The optimized formulation was then evaluated in terms of size, encapsulation efficiencies, drug loading, in vitro release profile, distribution and pharmacokinetics. According to the mathematic models, the optimal prescription and preparation technology can be conducted at the concentration of PLGA of 2%, the rotation speed of 1000 rpm and the mass ratio (CAP/PLGA) 1:2. The optimized CAP-MS resulted in spherical shapes and possessed a smooth surface. Average diameter, encapsulation efficiency and drug loading were turned out to be 4.73μm, 82.82% and 27.60%, respectively. In vitro release study represented a low initial burst release of approximately 21.26% within the first 24 h followed by a prolonged release up to 12 days and the release kinetics fitted well to the Higuchi model. In vivo results demonstrated that the drug suspension released rapidly after subcutaneous injection, the accumulate drug release was more than 97% after 12 hours, while the drug loaded microspheres release proﬁle showed a large initial burst effect (59%), and then released slowly, nearly 100% of capsaicin released at the end of 20 days. These results indicate the PLGA microspheres is a promising system that could be exploited as a delivery system for capsaicin with high drug loading capacity and sustained drug release.
Hydroxyapatite (HAp) – polycaprolactone (PCL) composite has found enhanced interest as scaffold material for bone tissue engineering application. The HAp phase is bioactive and provide the favorable environment for cell adhesion, proliferation, differentiation and cell conduction whereas the biodegradable PCL provide the required flexibility, mouldability and resorbability. Nanoparticles of HAp has been synthesized by precipitation method from Ca(NO3)2.4H2O and H3PO4 as precursors of Ca and P using tetrahydrofuran (THF) as the medium. The powder prepared was characterized for phase purity, functional group, particle size, surface area and morphology in comparison with the powder prepared using deionised water as the medium. By following the similar procedure of precipitation, nanoHAp was prepared in the PCL matrix with HAp to PCL ratio of 80:20 by wt % and HAp-PCL composite powder was filtered, dried at <50°C and characterized. The synthesized HAp and HAp-PCL composite show nano sized primary particles having X-ray pure hydroxyapatite phase. The HAp-PCL composite having homogeneous distribution of nanoHAp particles in PCL matrix could be a potential scaffold material for tissue engineering applications.
In this study one of classical antibiotic compound nitrofurantoin was studied as micro and nano particles in electrochemical analysis by cyclic voltammetric technique using glassy carbon electrode in blood medium to observe the oxidative effect on the blood components. It was found oxidation – reduction current peaks of nitrofurantoin in blood medium at +1 and -0.75 V respectively. The oxidation current peak was disappeared for the nitrofurantoin nano particles in blood medium, but for micro particles is still oxidize the blood. Different concentration and scan rate were studied to observation the electrochemical behavior of nitrofurantoin nano particles in blood medium which has good analysis.
Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2017; Vol 1; Issue 1 (March 30)
Heme-based Metalloproteins play essential part as nano-biosensor for diatomic gases such as NO, O2, CO and so on. The electron and optic properties, and adsorption energy of Heme complex as the nano-biosensor for O2 and CO gases were studied using ab initio studies and density function theory (DFT) approach. The results show that Heme is highly capable of being used as a nano-biosensor for O2 and CO gases. Carbon monoxide has a lower adsorption energy but higher electron transfers with Heme. Energy gap raised to 0.09 eV in the presence of O2 and to 0.39 Ev in the presence of CO, which indicates the higher sensitivity of Heme to CO.
KCC-1/bpt/Pd catalyst was readily prepared for first time from inexpensive starting materials in aqueous media which catalyzed the synthesis 1,4-dihydropyridines and 2-vinyl furans. High catalytic activity and ease of recovery from the reaction mixture using filtration, and several reuse times without significant losses in performance are additional eco-friendly attributes of this catalytic system.
Magnetic nanoparticles of cobalt ferrite (CoFe2O4) have been synthesized by chemical co-precipitation method with capable of controlling the average particle size of CoFe2O4 magnetic nanoparticles. Further, the surface of CoFe2O4 nanoparticles was coated with sodium oleate as the primary layer and polyethylene glycol 6000 (PEG-6000) as the second layer. X-ray diffraction (XRD) indicated the sole existence of partially inverse cubic spinel phase of CoFe2O4 and the average particle size calculated from XRD of about 29 nm. SEM analysis showed that the surface modification with PEG could increase crystallinity of nanoparticles, decrease the agglomeration and control the shape to more spherical. Fourier transform infrared spectroscopy (FT-IR) analysis indicated existence of two distinct surfactants on the particle surface. In addition, the results of FT-IR indicated that the coated CoFe2O4 particles improved with the thermal stability due to the interaction between the CoFe2O4 particles and protective layers. Magnetic characterization of CoFe2O4 was studied by Electron spin resonance (ESR). The results showed that the existence PEG in the CoFe2O4 decrease the spin resonance of conduction electrons.
This work is focussed on the role of the angle of incidence of an incoming electromagnetic wave in its transmission through a subwavelength nano-hole in a thin, smooth, planar semiconductor plasmonic layer. Fully detailed calculations and results are exhibited for p- and s-polarizations of the incident wave for a variety of incident angles in the middle and far zones of the transmitted radiation. Our dyadic Green’s function formulation includes both (1) the electromagnetic field transmitted directly through the 2D plasmonic layer superposed with (2) the radiation emanating from the nano-hole. Interference fringes due to this superposition are explicitly exhibited. Based on an integral equation formulation, this dyadic Green’s function approach does not involve any appeal to ideal metallic boundary conditions. It does incorporate the role of the 2D plasmon of the semiconductor layer, which is smeared due to its lateral wave number dependence.
We find that the interference fringes, which are clustered near the nano-hole, flatten to a uniform level of transmission directly through the sheet alone at large distances from the nano-hole. Furthermore, as the incident angle increases, the axis of the relatively large central transmission maximum through the nano-hole follows it, accompanied by a spatial compression of interference fringe maxima forward of the large central transmission maximum, and a spatial thinning of the fringe maxima behind it. For p-polarization, the transmission results show a strong increase as the incident angle 0 increases, mainly in the dominant Ez component (notwithstanding a concomitant decrease of the Ex component as 0 increases). We also find that in the case of s-polarization of the incident electromagnetic wave, the transmission decreases as 0 increases. These results, for both p- and s-polarizations, are consistent with earlier results for perfect metal boundary conditions, although such ideal boundary conditions are not invoked here as we have treated the problem of a nano-hole in a semiconductor layer and have determined its electromagnetic transmission including the role of its two dimensional plasma.
It is ineluctable that language is a clear truism of the challenging of the human mind and it connects impressively to the brain. It has been investigated that neurotransmitters such as dopamine control human speech mechanism. In this work, it has been clarified the relation between language and brain through the chemical neurotransmitter by measuring the physicochemical properties of relative energy, Van der Waals forces and dipole moment via computational modeling. Then thermodynamic properties have been calculated by infrared radiation to recognize the active sites of dopamine structure and comparing it by some other neurotransmitters. In this paper, it has been exhibited that how dopamine can be effective for learning a new language and makes it easier and enjoyable.
Shells of Jatorpha curcas is commonly used as fuel and as soil fertilizer. In our study, we investigate the use of shells to synthesize nanoscale particles by mechanical grinding via top down approach. The shade-dried shells are subjected to high energy milling to produce nanoparticles and the collected powder is characterized for their particle size, crystallinity, functional group and elemental composition. Antimicrobial activity of the prepared nanoparticles reveals the significant inhibitory effect against Gram positive bacteria (S. aureus and S. epidermis) and gram negative bacteria (E. coli and K. pneumoniae). Growth of gram positive organism is found to be reduced by 50-60 % when the particle size is increased from 1 to 20 mg/ml whereas gram negative bacteria has 30-45 % of growth reduction. When compared to control, shell nanoparticles exhibit an excellent antioxidant activity about at 78 % at 20 mg/ml against DPPH reagent. This preliminary evaluation for the bioactivity of shell nanoparticles from Jatropha lead the future biorefinery processing of Jatropha plant materials into cost effective biological product development.
Present study inspects the profiles of self-polarization effect (SPE) of impurity doped GaAs quantum dots (QDs) in presence of noise. Noise term maintains a Gaussian white character and it has been introduced to the system via two different pathways; additive and multiplicative. In view of a comprehensive analysis, modulation of SPE has been scrutinized along with the variations of several relevant quantities such as electric field, magnetic field, confinement potential, dopant location, dopant potential, noise strength and aluminium concentration (only for AlxGa1−xAs QD). Application of noise affects SPE noticeably. However, the extent to which SPE is altered depends on the noise strength domain and the pathway through which noise is applied. The outcomes of the study delineate viable routes to tune the SPE of doped QD system, particularly in presence of noise.
We derive the Schrödinger eigen-energy dispersion relation for electrons on a two dimensional sheet with a one dimensional periodic lattice of quantum antidot potential barriers, in the presence of a strong perpendicular magnetic field. This system is Landau quantized by the high magnetic field and we determine the associated Green’s function for propagation along the axis of the antidot lattice, which we use to formulate the dispersion relation for the energy spectrum analytically in a closed form in terms of the Jacobi Theta Function (3rd kind). An approximate solution for the Landau quantized eigen-energies is obtained in terms of Laguerre polynomials, and the development of Landau minibands is explicitly exhibited.
The paper presents some advances of a vacuum nano-transistor, known as Nothing On Insulator NOI device. The breakdown limitations are considered for ultra-thin buried oxide and different semiconductor islands shape. The relationship between oxide / semiconductor thickness and the breakdown voltage of the structure allow the gate limit voltage increasing from -6.5V to -12V using 15nm instead 10nm buried oxide. Reshaping the NOI transistor, a special semiconductor wall with one cube of roughnesses is analysed. The 1-cube variant has intermediate performances, as the maximum current capabilities.
Metal nanoparticles are of interest for different biomedical and technical applications, for example by conjugation with DNA, enzymes or other biomolecules, for on-chip-labeling, for SERS-analytics, for heterogeneous catalysis and as antibacterial additives. Non-spherical metal nanoparticles are in the focus of developments due to their size- and shape-dependent optical properties. Recent results on the synthesis and behavior of noble metal nanoparticles are discussed from the point of view of the electric behaviour. The particle growth by a metal-catalyzed reductive metal deposition in liquid phase is regarded as an open-circuit mixed electrode system. Potential formation and the related electric charging of metal nanoparticles lead to self-polarization effects. These effects enforce spontaneous symmetry breaking effects during the formation of metal nanoparticles and explain the growth of non-spherical particles with high aspect ratios.