In-situ preparation and characterization of acid functionalized single walled carbon nanotubes with polyimide nanofibers.

Nanofiber composites (Polyimide/f-SWCNT) of Pyromellitic dianhydride, 4,4'-Oxydianiline, and 4,4'-(4,4'-isopropylidene diphenyl-1,1'-diyl dioxy) dianiline (PMDA-ODA/IDDA) and surface-functionalized single walled carbon nanotubes (f-SWCNT) were made by electrospinning a solution of poly(amic acid) (PAA) containing 0-2 wt% f-SWCNT followed by thermal imidization. X-ray photoelectron spectroscopy spectra verified the oxidation of SWCNT surface after acid treatment, and indicated possible hydrogen bonding interactions between the f-SWCNTs and polyamic acid. High-resolution scanning electron microscopy images showed the average diameter of nanofibers to be below 150 nm, and transmission electron microscopy images showed that SWCNTs were aligned inside the polymer nanofiber. In thermogravimetric analysis, all composites showed increased thermal stability with increasing f-SWCNT content compared to neat PI. Storage modulus also increased from 124 MPa to 229 MPa from neat PI to 2% f-SWCNT composite.

Tuning the Magnetic Properties of Iron Oxide Nanoparticles by a Room-Temperature Air-Atmosphere (RTAA) Co-Precipitation Method.

The ability of a room-temperature air-atmosphere (RTAA) co-precipitation method to tune the magnetic properties of iron oxide nanoparticles was investigated. It was demonstrated that superparamagnetic nanoparticles with different particle sizes ranging from 7 to 25 nm and magnetic properties with saturation magnetization between 2 to 75 emu g(-1) can be synthesized by simply controlling the molar ratio of ferrous to ferric ions and the concentration of ammonium solution, without heat treatment or oxygen-level control. It was revealed that the tuning of the magnetic properties was associated with the compositional control between magnetite and maghemite. Ammonium concentration was also an important factor to obtain dispersed superparamagnetic (SPM) or ferrimagnetic (FM) nanoparticles.

A single step culture technique for tubercle bacilli.

A single step method for the digestion and decontamination of sputum for culture of tubercle bacilli is described. This method employs a transport medium containing tri-sodium phosphate and penicillin. Sputum samples are collected directly into the medium and, after standing overnight, deposits are inoculated into Löwenstein-Jensen medium. The method was found to be superior to several other commonly used techniques and it avoids the problems of lengthy, multi-step procedures with associated risks of contamination from the atmosphere, costly reagents, the killing of tubercle bacilli by over-exposure to decontaminating agents, the unpleasantness of manipulating unprocessed sputum and the need for sophisticated equipment and special technical skills. The method is therefore ideal for use under the prevailing laboratory conditions in the developing countries.

Brief communication: rapid culture of tubercle bacilli.

One of the biggest obstacles to the correct diagnosis and efficient treatment of tuberculosis is the absence of a rapid technique for culturing tubercle bacilli and for testing their susceptibility to antituberculosis drugs. Current procedures typically take 6-10 weeks to perform. This article describes a simple, rapid, reliable and cheap method of culturing tubercle bacilli using a liquid medium consisting of a mixture of coconut water, horse serum, glycerol and benzylpenicillin. Addition of specific concentrations of antituberculosis drugs to the medium, permits information on the drug susceptibility of tubercle bacilli to be obtained in only 6 days. The procedure requires no special instruments or technical skill and can therefore be carried out routinely in the average laboratory in developing countries.

A cold staining method for acid-fast bacilli.

The Ziehl-Neelsen method is probably the best known and most frequently used procedure for staining tubercle bacilli. The method requires controlled heating for its success. However, in developing countries, such as India, where most laboratories rely mainly on spirit lamps as a source of heat, the Ziehl-Neelsen method often cannot be carried out because rectified spirit is difficult to obtain. The study describes a cold staining technique that uses the same staining solutions as the conventional Ziehl-Neelsen method. For direct smears, the correlation of results of the cold staining procedure with those of the Ziehl-Neelsen method was 97% and for concentrated smears was 99%. The method described is suitable for use in basically equipped laboratories.