A new method for titania thin film production

In this research, transparent titania (TiO2) thin films were deposited on a glass microscope slide and on a flexible polyethylene terephthalate (PET) substrate under a high vacuum condition by means of the thermionic vacuum arc (TVA) method in a very short period of time (60 s). Optical properties and surface properties of the coated TiO2 surfaces are related to the structural changes of the coated layers due to ion energies and substrate effect. But obtained results are closely linked to literature values. Our analysis showed that the TVA method is an alternative method for low-temperature coatings and the produced films present important advantages for optical and industrial applications.

Novel Microtechnology System for Cytometric Analysis of Adherent Cell Populations

The increasing appreciation of tissue cellular heterogeneity and recent identification of rare cell populations within tissues that are associated with specific biological behaviors, e.g., progenitor cells, has illuminated a limitation of current technologies to study such adherent cells directly from primary tissues. The micropallet array is a recently-developed technology designed to address this limitation by virtue of its capacity to isolate and recover single adherent cells on individual micropallets [1]. Micropallet arrays consist of hundreds of thousands of microscale polymer pedestals (“micropallets”) uniformly arrayed on a glass microscope slide. The micropallets are made from a high aspect photopolymerizable polymer using photolithographic methods. Cells are applied to the arrays and fall stochastically upon its surface, with single cells adhering to individual micropallets. Cells are then analyzed in situ and single, unperturbed cells can be selected and collected from the array by releasing the underlying micropallets using a focused pulsed laser.

Planar Waveguide Genetic Assay Readout Device

A planar waveguide (PWG) device has been developed for the detection of fluorescently labeled nucleic acid sequences immobilized or hybridized to the surface of a planar waveguide. Unlike current technologies requiring image gathering and reading capabilities or specially textured waveguide surfaces, this instrument uses simple glass slide based arrays, providing a numerical output in proportion to the fluorescent intensity recorded. The system consists of an optical waveguide (a glass microscope slide), an excitation light source, a photo detector, filters for select fluorescent emissions and the positioning array cassette. A data analysis algorithm is presented for interpretation of two dimensionally organized arrays. Based on our experimental evaluations we conclude that this sensing system shows promise as a simple and effective means to read fluorescent microarrays.

Planar Waveguide: Utility in Amino Acid Detection

A device for the detection of fluorescently labeled nucleic acid sequences immobilized or hybridized to the surface of a planar waveguide has been developed. The device described requires no image gathering or analysis utilities, nor any specially patterned waveguide surface for detection. The system consists of an excitation light source and a photo detector, filters for select fluorescent emissions and a standard glass microscope slide that functions as a planar waveguide (PWG) and assay substrate. The device can discriminate fluorescent DNA products hybridized to a glass based array as effectively as laser based reader instruments, and is a low cost system with a high potential for full automation. The system’s functional parameters are presented along with design schematics of current prototypes. Performance data is also presented showing test results comparable to pre-established fluorescence detection means. Future design goals are also discussed. It is concluded that as a component in telemedicine or other remote medical care strategies, the detection means presented can play a significant role in bringing molecular diagnosis and gene detection to arenas of medical care where it is currently unavailable.

Sequence Specific Force Curves Measured by Mechanically Opening the DNA Double Helix

Using techniques of molecular biology, we have designed a molecular construction which allows to attach the two complementary strands of one end of a single molecule of bacteriophage λ DNA separately to a glass microscope slide and a microscopic bead. A soft microneedle acting as a force sensor is chemically attached to the bead and its deflection is measured by an optical microscope. Keeping the base of the force lever fixed, the glass slide is displaced slowly, leading to a progressive opening of the double helix. The force measured during the opening process shows a characteristic variation which is related to the sequence of the bases along the DNA molecule. We present a brief summary of the present state of our work.

Epoxy Slide Embedment for LM, TEM, STEM and HVEM Cytochemistry

The selection of cytochemical and immunocytochemical specimens for semi thin sectioning for STEM or HVEM and ultrathin sectioning for TEM is enhanced by the ability to survey cytochemically stained specimens by light microscopy (LM). Procedures previously reported for this purpose, generally involve embedding the specimen between Teflon coated coverslips. The release of the embedded Specimen from the coverslip is sometimes difficult. Addition ally, the small specimen must be attached to a glass microscope slide for LM viewing. Reported here is a newly devised one-step casting procedure that provides for the embedment of stained cells or tissue sections in the form of an epoxy microscope slide that circumvents these problems.

A non-fatal method of sex determination for patellacean gastropods

During our studies of the reproductive cycles in limpets (family Acmaeidae) we have been confronted by the lack of a method to determine sex without killing the animals. Previous studies have relied upon dissection or histological sectioning to determine sex. This note describes a technique which allows the determination of sex in patellacean limpets without killing the animal.The tools needed are a syringe (1 cc) with a hypodermic needle (we have found that a 26 gauge, 16 mm needle works well with specimens larger than 10 mm in length), and a glass microscope slide. After removing the limpet from the substratum the shell is held with the aperture down. As the animal extends its foot downward it exposes and stretches the sides of the body wall. When the posterior portion of the body wall is fully exposed the needle is inserted approximately one third of the way up the body wall towards the shell attachment muscle. The orientation of the needle should be in line with the plane of the aperture. Penetration of the gonad can be felt by a ‘breaking through’ or sudden decrease in resistance to the progress of the needle. Care should be taken to avoid penetrating further than necessary because other organs can be easily damaged. Drawing the sample requires more force and time (approximately 10 s) than one would expect. When withdrawing the needle constant tension on the syringe plunger is necessary to keep the sample in the needle. The contents of the needle are then emptied on to the glass slide.

Hole Formation in Gold Films

During recent experiments on Au films, a qualitative correlation between hole formation and deposition rate was observed. These early studies were concerned with films 80 to 1000A thick deposited on glass at -185°C and annealed at 170°C. In the present studies this earlier work was made quantitative. Deposition rates varying between 5 and 700 A/min were used. The effects of deposition rate on hole density for two films 300 and 700A thick were investigated.Au was evaporated from an outgassed W filament located 10 cm from a glass microscope slide substrate and a quartz crystal film thickness monitor. A shutter separating the filament from the substrate and monitor made it possible to obtain a constant evaporation rate before initiating deposition. The pressure was reduced to less than 1 x 10-6 torr prior to cooling the substrate with liquid nitrogen. The substrate was cooled in 15 minutes during which the pressure continued to drop to the mid 10-7 torr range, where deposition was begun.

The Dip-Slide: a modified dip-inoculum transport medium for the laboratory diagnosis of infections of the urinary tract

The dip-slide, consisting of a glass microscope slide coated with nutrient medium and inoculated by dipping in freshly voided urine, provides a simple measure of the bacterial concentration in fresh urine. This is a useful supplement to the usual microscopy and culture of urine in the diagnosis of urinary tract infections in general practice, when specimens cannot be delivered to a laboratory within several hours of collection, particularly when urine specimens have to travel by post. Dip-slides are also useful as the sole test in screening for symptomless bacteriuria.