Effect of Gold Nanoparticles Size Capped with Surfactant on the Transformation of Plasmid into Escherichia coli Bacteria

Bacterial transformation has great importance in molecular biology, as it is used for introduction of foreign genes into bacterial cells either chemical or physical ways. Using calcium chloride to prepare competent cells and heat shock is the most widely used method for bacterial transformation. This method is an efficient and convenient technique but it has in some extent low transformation efficiency. Here we report the use of nanoparticles that significantly improve the transformation efficiency up to 10 times higher than the standard heat shock method by the assistance of (˜ 15, 25 nm) SDS capped gold nanoparticles in the transformation process that leads to the formation of temporary nano-channels across the bacterial cell wall to deliver plasmids into cells. Transformation of bacteria with plasmid was examined using Β-galactosidase assay.

Recycling of the Al Scrap: The Effect of Adding Inoculant Nb+B and Mg with Subsequent Heat-Treatment in the Mechanical Behavior of Al Alloy

A new perspective for the use of Al-Si alloys produced with recycled Al (with Fe>1%) in Gravity Die Casting (GDC) processes. To study the morphology of ß-Fe precipitates and the material’s mechanical properties were added the inoculate via Nb+B and the element Mg with subsequent heat treatment. The samples were cast in Al10Si1Fe0.35Mg alloy in a metal mould according to ASTM B108. The microstructure was analyzed with BSE-SEM and EDS. The work investigated the morphology of ß-Fe precipitates and their effects and interactions on the material’s mechanical properties. The combined effect resulted in reduced size and shape of ß-Fe precipitates, thereby improved higher yield strength (YS = 207.71 MPa), ultimate tensile strength (UTS = 300.35 MPa), and elongation of 4.66%, exceeding the strength and elongation limit values found in commercial alloys, such as ASTM A357 alloy, where the Fe content is low (max. 0.2%).

Superimposed Quantum Dots: Emerging Optoelectronics

As everybody knows that electron, phonon, and photon transport in solids (crystals) depends on lattice physical properties. Manipulation of propagation properties needs to manipulate crystal parameters such as lattice constant, atoms in the lattice, etc. There are a limited number of crystalline structures in nature to manipulate charge, phonon, and photon transfer in electronics, acoustics, and photonics. The basic problem is how one can make single crystals with desired charge, phonon, and photon transfer performance? Also, how one can manipulate the mechanical, optical, and electrical performance of a device? It seems that nanotechnology and especially nanoparticles and superimposed nanocrystals can help to solve this problem. In this short letter, the superposition of Quantum Dots as a solution to enhance the capability of device designers in this regard is presented, discussed, and demonstrated by simple numerical simulation. If we use the superimposition of QDs, we can realize multi wavelength lasers in a single cavity [1,2]. The ultra-broadband semiconductor optical amplifiers can be implemented by this idea [3]. Multi wavelength photodetector with multi-electrical output is another most important application that can be realized using this idea [4]. High-efficiency solar concentrator based on superimposed QDs is introduced in [5]. Other interesting applications can be realized using the proposed idea too. All these advantages are related to optical and electrical properties dependency on the size of nanocrystals [6]. So, it is possible to make different crystals using the superimposition of well-known crystals. To demonstrate that, first, by choosing different crystals, and using the superposition of those, it is shown that the obtained structure is similar to a new crystal with a lattice constant that depends on initial superimposed crystal lattice constants as well as a geometrical combination of those. In the second part, we show that using colloidal QDs, it is so easy to combine different QDs with different sizes in a unique solution and a superimposed QDs with the desired density of each QDs will be available.

Study on Enteric Vacant Capsules Based on Hydroxypropyl Methylcellulose Phthalate-55S

The formulation and preparation technology of enteric cellulose hollow capsules were studied, and its properties were evaluated. The enteric cellulose hollow capsules were prepared with hydroxypropyl methylcellulose phthalate~55S (Hp55S) as film~forming material, agar as molding agent and hydroxypropyl methylcellulose (HPMC) as disintegration regulator. The preparation process was as follows: (1) At room temperature, 9~16 phr of Hp55S was dissolved in 30~50 phr of dilute ammonia solution with pH of 10~11 to obtain transparent Hp55S glue solution; (2) Put 1.2~1.6 parts of agar into 50~70 parts of water, heat and boil to obtain agar solution. 1~7 phr of HPMC, 0.12~0.16 phr of KCl and 0.1~0.2 phr of Tween~80 were poured into agar solution to disperse evenly, and then the temperature of gel solution was reduced to 50~55 oC to obtain agar/HPMC mixed gel solution; (3) The Hp55S solution was heated to 50~55 oC and then poured into agar/HPMC solution to obtain composite cellulose solution. The temperature of the solution was kept at 50~55 oC. (4) Enteric cellulose hollow capsules were prepared by dipping in glue, shaping, drying, trimming and assembling. The results showed that the enteric cellulose hollow capsules met the quality requirements of “enteric coated hollow capsules” in Chinese Pharmacopoeia. Compared with the traditional formula and preparation process of enteric coated hollow capsules, it avoids the use of organic solvents and multiple molding process. The enteric cellulose hollow capsule greatly reduces the preparation cost from the formula to the process, which is green, safe and environmental friendly, and has good application value.

A New Strategy for the Preparation of Porous Silk Fibroin Scaffolds

In order to prepare Silk Fibroin (SF) scaffolds with excellent pore structure, the fresh SF solution was concentrated at relative humidity 55% and 25°C for 3 days. During the above process, SF micelles, existed in the fresh SF solution, aggregated into nanofilaments as concentration increased, and the nanofilament feature of SF were similar to that observed in silk gland. SF nanofilaments were easy to form SF scaffolds with porous and silk I structure, in contrary, SF micelles were liable for formation of SF scaffolds with lamellar and random coil structure. It suggested that the formation of SF nanofilaments is a critical step for pore and secondary structure control of lyophilized SF scaffolds.