Replication of cancer cells using soft lithography bioimprint technique

Replication of biological cells for the purpose of imaging and analysis under electron and scanning probe microscopy has facilitated the opportunity to study and examine some molecular processes of living cells in a manner that was not possible before. The difficulties faced in direct cellular analysis when using and operating atomic force microscopy (AFM) in situ for morphological studies of biological cells has lead to the development of a novel method for biological cell studies based on nanoimprint lithography. The realisation of the full potential of high-resolution AFM imaging has revealed some very important biological events such as exocytosis and endocytosis. In this work, a soft lithography bioimprint replication technique, which involved simple fabrication steps, was used to form a hard replica of the cell employing a newly developed biocompatible polymer that has fast curing time at room temperature essential for this process. The structure and topography of the endometrial (Ishikawa) cancer cell was investigated in this study. Cells were cultured and incubated in accordance with standard biological culturing procedures and protocols approved by the Human Ethics Committee, University of Otago. An impression of the cell profile was created by applying a layer of the polymer onto the cells attached to a substrate and rapidly cured under UV-light. Fast UV radiation helps to lock cellular processes within minutes after exposure and replicas of the cancer cells exhibit ultra-cellular structures and features down to nanometer scale. Elimination of the AFM tip damping effects due to probing of the soft biological tissue allows imaging with unprecedented resolution. High-resolution AFM imagery provides the opportunity to examine the structure and topography of the cells closely so that any abnormalities can be identified. Craters that resemble granules may be observed. These represent steps on a transitional series of sequential structures that indicate either an endocytotic or exocytotic processes, which were evident on the replicas. These events, together with exocytosis, play a very significant part in the tumorigenesis of these cancer cells. By forming cell replica impressions, not only have they the potential to understand biological cell conditions, but may also benefit in synthesizing three dimensional (3-D) scaffolds for natural growth of biological cells and provide an improvement over standard cell growth conditions.     

Oxidation of Hafnium Carbide and Titanium Carbide Single Crystals with the Formation of Carbon at High Temperatures and Low Oxygen Pressures

The isothermal oxidation of the 200 face of HfC and TiC single crystals was performed at temperatures of 700°—1500°C and at oxygen pressures of 0.08—80 kPa for 4 h. The weight gain by oxidation of the two crystals was followed using an electromicrobalance. A polished cross section of the oxidized crystals was observed using backscattered electron imaging in a scanning electron microscope. Quantitative chemical analysis for Hf, Ti, O, and C was performed by wavelength-dispersive X-ray microanalysis. The early-stage oxidation kinetics of HfC crystals were described by the contracting volume equation, followed by slowed reaction in the latter stage, whereas the same equation was applied to the oxidation of TiC over the entire oxidation time. The preferred {200} orientation of monoclinic HfO₂ occurred on the oxidized surface of the HfC crystal. The oxide scale on the HfC crystal consisted of a compact and pore-free black inner scale (zone 1) and a white/gray outer scale that contained many pores (zone 2). Zone 1 contained ∼25 at.% unoxidized carbon, and zone 2 contained 6—11 at.% carbon. The oxide scale of TiC was composed of an inner dense lamella subscale (zone 1) with a carbon content of 7—23 at.% and an outer region with laminations that was separated by pores and cracks (zone 2). The Ti₃O₅ phase, which exhibits a strong 020 line, was formed at depths of ≥40 μm in the scale obtained at 1500°C. Treatment with a concentrated HF solution allowed zone 1 to be separated from the HfC crystal in the form of carbon-containing films, which were characterized using Raman spectroscopy and transmission electron microscopy.     

Anterior sacral meningocele associated with lumbar spondylodiscitis: contribution of images

The use of fiber bronchoscopy (FBS) for early diagnosis of aspiration in patients with grave craniocerebral (CCI) and combined injury is analyzed. Aspiration is not always associated with a clear-cut clinical picture in this cohort of patients, and x-ray examination of thoracic organs during the first hours after the injury is ineffective. High diagnostic potentials of BFS and possibility of removing the contents from the tracheobronchial tree under visual control dictate this measure for all cases with grave CCI and combined injuries during the first hours of hospitalization.     

Respiratory manifestations of carbamazepine. Apropos of a case

A 14-year-old girl developed skin rash, fever and dyspnea. The chest roentgenogram showed diffuse reticulonodular infiltration. Pulmonary function tests revealed mild restrictive defect and blood oxygen pressure at 71 mm Hg. BAL showed increased cell counts with lymphocytosis at 15% and neutrophilia at 3%. Outcome was good after carbamazepine withdrawal and without corticosteroid therapy. Relapse was observed after patient-induced rechallenge.     

New scheme of digital watermarking using an adaptive embedding strength applied on multiresolution filed by 9/7 wavelet

Digital image watermarking is still a new field for research. In fact, digital watermarking is the best tool for the copyright protection and the authentication of the digital data. Researches are interested in the tradeoff that exists between the insertion capacity, the imperceptibility, and the robustness. The embedding function has a great influence on these characteristics. Channel coding techniques are used to reduce the error probability of the hidden watermark. On the other hand, the watermark strength is adapted according to human visual perception. In this article, we present a new scheme to achieve the embedding function in the framework of a robust and nonblind watermarking in multiresolution field by 9/7 wavelet of Daubechies. Indeed, we replace the constant embedding strength by a variable coefficient based on the logarithmic function. This coefficient is adaptive according to the magnitude of the wavelet transform magnitude that will be watermarked. This adaptive scheme reduces the computational error and enhances the robustness and the imperceptibility. Experimental results are presented to show that our scheme gives a better correlation and an improved PSNR. They demonstrate that the detection is enhanced. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 16, 249–257, 2006     

A new family of Grassmann space-time codes for non-coherent MIMO systems

A family of space-time codes suited for noncoherent multi-input multi-output (MIMO) systems is presented. These codes use all the complex degrees of freedom of the system, i.e. M/spl times/(1-(M/T)) symbols per channel use. They are constructed as codes on the Grassmann manifold G/sub T,M/(/spl Copf/) where T is the temporal codelength and M is the number of transmit antennas.     

First pseudo-grain failure model for inelastic composites with misaligned short fibers

This paper presents a new model and an experimental investigation of the elastic–plastic flow until failure in short-fiber reinforced thermoplastics typically produced by injection molding. The distribution of fiber orientations and lengths is reproduced statistically within a representative volume element (RVE) of the composite microstructure. Then, the RVE is decomposed fictitiously into pseudo-grains (PGs) inside of which the fiber orientation and aspect ratio are unique. An incremental Mori–Tanaka model is used to predict the phase averages of the stresses and strains inside each PG. Damage intervenes in a second homogenization step: the macroscopic stress accounts for the fact that PGs fail one after the other in function of the fiber orientation and the applied strain mode. Hence, the model is called “first pseudo-grain failure model” by analogy with the “first ply failure model” in laminated composites. An evaluation of the proposed model against experimental data is conducted for short-glass-fiber reinforced polyamide 6,6 (PA6,6). It is shown that the model yields satisfactory predictions of the response under uniaxial tension of composite samples with different fiber contents cut under various directions relative to the main injection flow direction.     

Inorganic/organic (SiO₂)/PEO hybrid electrospun nanofibers produced from a modified sol and their surface modification possibilities

Ceramic silica (SiO(2)) hybrid nanofibers were prepared by electrospinning of solutions containing biocompatible polymer and modified silica precursors. The new hybrid nanofibers are based on polyethylene oxide (PEO) and a new solution of modified sol-gel particles of mixture containing tetraethoxysilane (TEOS) and 3-glycidyloxypropyltriethoxysilane (GPTEOS) in a weight ratio of 3:1. Adding high-molecular-weight PEO into the silica sol is found to enhance the formation of the silica nanofibers and leads to reduce the water-soluble carrying polymer down to 1.2%wt. Transmission electron microscopy (TEM) and attenuated total reflection fourier transformation infrared ATR-FTIR measurements are suggested that PEO is encapsulated by the silica component. This excellent formulation renders electrospinning of SiO(2) a robust process for an easy production of controllable silicate nanofibrous matrices. For instance, nanofibers with average diameter down to 400 nm are accessible by varying the weight ratio between the polymer and the inorganic precursor. These are reduced to 120 nm after the pyrolysis process. Moreover, the surface of the nanofibers could be easily modified, either by Al(3+) leading to aluminium silicate coatings, or by incorporation of Ca(2+) ions and subsequent bioactive hydroxyl carbonate apatite (HAP) formation. These hybrid silica nanofibers are possess a unique collective properties can have a great impact either in high-temperature reinforced materials and filtration or in biomedical applications such as in dentistry and bone tissue engineering.     

Optimization of <Emphasis Type="Italic">Aspergillus oryzae</Emphasis> S2 α-amylase,ascorbic acid,and glucose oxidase combination for improved French and composite Ukrainian wheat dough properties and bread quality using a mixture design approach

A simplex-centroid experimental design was used for the optimization of both reducing and oxidizing improvers, namely Aspergillus oryzae S2 α-amylase (Amy), ascorbic acid (Asc), and glucose oxidase (GOD). This optimization was performed to enhance the dough and breadmaking qualities of soft French wheat flour and a composite counterpart that contained 30% Ukrainian wheat flour. Statistically significant correlations were calculated between the W index and textural parameters (e.g., dough chewiness and bread cohesiveness). The findings revealed that while the best mixture for French flour comprised 21.8% of Amy, 41.2% of Asc, and 37% of GOD, for the composite counterpart, it comprised 2.3% of Amy, 66% of Asc, and 31.7% of GOD. These optimized mixtures rearranged soft French wheat flour and its composite counterpart to a good quality and an improved flour texture, respectively. Additionally, they increased the loaf specific volumes of the breads made from soft French wheat flour and its counterpart by 25.8 and 45.43%, respectively, significantly decreased the breads’ susceptibility to microbial contamination, and reclassified the breads as “good” in terms of sensory attributes.