Grey-scale silicon diffractive optics for selective laser ablation of thin conductive films.

Laser beam shaping can play a crucial role in improving many laser processes, especially in selective laser patterning of thin films for display devices and solar cells. Typical Gaussian spatial energy distributions can increase damage to the substrate and lead to large crater edge ridges, which are sub-optimal for typical industrial thin film processes. We report on the design, fabrication, and testing of reflective silicon diffractive optics developed for spatial beam shaping at a wavelength of 355 nm. The application of the elements for laser-selective removal of 20 nm indium tin oxide thin films on glass substrates is demonstrated. The design of the phase profile is first generated using the numerical method of computer-generated holography. The phase profiles are realized on a silicon substrate using a novel two-step fabrication technique consisting of a calibrated focused ion beam and an inductively coupled plasma etch. This results in truly grey-scale, blazed diffractive optics, which were analyzed using white light interferometry and atomic force microscopy. Using the diffractive elements with 355 nm nanosecond pulses shows excellent focused spot profiles with a good reproduction of the intended design with a first-order off-axis diffractive efficiency of approximately 80% at a 45 deg angle of incidence.

Characterization of a weakly expressed KIR2DL1 variant reveals a novel upstream promoter that controls KIR expression.

Members of the human KIR (killer cell immunoglobulin-like receptor) class I major histocompatibility complex receptor gene family contain multiple promoters that determine the variegated expression of KIR on natural killer cells. In order to identify novel genetic alterations associated with decreased KIR expression, a group of donors was characterized for KIR gene content, transcripts and protein expression. An individual with a single copy of the KIR2DL1 gene but a very low level of gene expression was identified. The low expression phenotype was associated with a single-nucleotide polymorphism (SNP) that created a binding site for the inhibitory ZEB1 (Zinc finger E-box-binding homeobox 1) transcription factor adjacent to a c-Myc binding site previously implicated in distal promoter activity. Individuals possessing this SNP had a substantial decrease in distal KIR2DL1 transcripts initiating from a novel intermediate promoter located 230 bp upstream of the proximal promoter start site. Surprisingly, there was no decrease in transcription from the KIR2DL1 proximal promoter. Reduced intermediate promoter activity revealed the existence of alternatively spliced KIR2DL1 transcripts containing premature termination codons that initiated from the proximal KIR2DL1 promoter. Altogether, these results indicate that distal transcripts are necessary for KIR2DL1 protein expression and are required for proper processing of sense transcripts from the bidirectional proximal promoter.

Confinement of laser-material interactions by metal film thickness for nanoparticle generation.

Understanding the formation and evolution of nanoparticles generated during laser ablation is imperative in controlling the health risk associated with the ablated material, minimizing contamination and enhancing ablation rates. There is also a keen interest in undertaking a competitive analysis of nanoparticle generation compared with current synthesis techniques. Laser-material-ambient interactions are, however, complex due to the dynamic nature of the ablation environment and consequently it is difficult to characterize the process of nanoparticle formation and evolution. Al, Ni and Au films with thicknesses of 10, 25 and 75 nm were ablated by single nano- and femto-second laser pulses. Generated nanoparticles were collected and their height and diameter measured using AFM and SEM, respectively. Results identified that the thickness of the metal film is highly influential on the size and distribution of nanoparticles e.g., mean radius for Au nanoparticles generated during femtosecond laser ablation of 75, 25 and 10 nm thick films were 5.9 nm, 3.5 nm and 1.8 nm, respectively. The standard deviation (sigma) of radii of these nanoparticles generated from 75, 25 and 10 nm thick films also decreased from 8 nm, 6 nm to 1 nm, respectively.

Activating KIR Haplotype Influences Clinical Outcome Following HLA-Matched Sibling Hematopoietic Stem Cell Transplantation.

Natural killer cells are thought to influence the outcome of hematopoietic stem cell transplant (HSCT), impacting on relapse, overall survival, graft versus host disease and the control of infection, in part through the complex interplay between the large and genetically diverse killer immunoglobulin-like receptor (KIR) family and their ligands. This study examined the relationship between KIR gene content and clinical outcomes including the control of opportunistic infections such as cytomegalovirus in the setting of human leucocyte antigen (HLA)-matched sibling HSCT in an Australian cohort. The presence of the KIR B haplotype which contain more activating receptors in the donor, in particular centromeric B haplotype genes (Cen-B), was associated with improved overall survival of patients with acute myeloid leukemia (AML) undergoing sibling HSCT and receiving myeloablative conditioning. Donor Cen-B haplotype was also associated with reduced acute graft versus host disease grades II-IV whereas donor telomeric-B haplotype was associated with decreased incidence of CMV reactivation. In contrast, we were not able to demonstrate a reduced rate of relapse when the donor had KIR Cen-B, however relapse with a donor Cen-A haplotype was a competing risk factor to poor overall survival. Here we show that the presence of donor activating KIR led to improved outcome for the patient, potentially through reduced relapse rates and decreased incidence of acute GvHD translating to improved overall survival. This article is protected by copyright. All rights reserved.

The effect of "Jelly" CdTe QD uptake on RAW264.7 monocytes: immune responses and cell fate study.

Encapsulation of Quantum Dots (QDs) has become an essential factor which regulates particles cytotoxicity, as well as physical and chemical stability. Negatively charged cellular membranes have a great affinity to nanoparticles with surface molecules carrying positive charge, hence creating perfect conditions for fast and aggressive intracellular penetration. The preference for non-charged outer shells is topical in QD design and various applications. In the current paper we develop gelatination as a prominent coating approach to create neutrally passivated QDs with improved biocompatibility. We have revealed the trends in particle's uptake, accumulation, intracellular localisation and retaining time as well as RAW264.7 monocyte cell fate and immune responses. Also the difference in particle endocytosis kinetics and dynamics has been shown to depend on the QD core size. The intracellular QD content along with cell responses at the population level was quantified by flow cytometry.

Characterisation of an antibody coated microcantilever as a potential immuno-based biosensor.

In this study, we investigated the activity, stability, lifetime and re-usability of monoclonal antibodies to myoglobin covalently immobilised onto microfabricated cantilever surfaces. These sensing surfaces are of interest to us in the development of novel cantilever-based immunosensors. For such sensors the antibody layer represents the sensing element while the microcantilever acts as a mechanical transducer. A procedure for producing re-usable biological coatings has been tested with different independent techniques. An Enzyme Linked Immunosorbent Assay (ELISA) was used to determine the presence of an active antibody coating, and to monitor the lifetime and stability of the immobilised antibody. Through this analysis, the activity of the immobilised antibody layer was found to be more stable with the introduction of sucrose, as a stabilising agent. Sucrose was applied to the immobilised antibody layer after each regeneration step. The immobilised antibody was found to have a stable active lifetime for up to 7 weeks. Fluorescence microscopy was used to give information on the distribution of the coating on the gold and silicon nitride sides of the cantilever. Atomic Force Microscopy was used to determine the presence of the biological coating on the cantilever and to obtain information on the surface morphology of the biological element of the sensor. The combined results provide valuable information on the development of an optimised sensing element and demonstrate a set of methods to use for future sensor-to-sensor characterisation. Preliminary experimental results showing the antibody activity against myoglobin, detected with a microcantilever based sensor prototype confirmed the motivations and potentialities of the proposed immunosensing technique.

Ocular cowpox: transmission from the domestic cat to man.

A clinicopathological case of ocular cowpox is reported. Cowpox is no longer regarded as being enzootic in cattle. The most likely mode of transmission of cowpox to man appears to be from the domestic cat or wild rodents.

A new synthetic material for the brow suspension procedure.

This report describes the use of a new synthetic material, combining polyester with carbon, in nine brow suspension procedures. The mechanical properties of polyester, with the fibrous tissue inducing properties of carbon, combine to produce a scaffolding on which fibrovascular ingrowth is possible. Subsequent fibrosis gives a permanent effect. Early results indicate that the material is tolerated well in the eyelid, but the problem of early slippage remains.

Dynamic retinoscopy.

Dynamic retinoscopy for the objective examination of accommodation was described in the ophthalmic literature in the 1890s but is rarely used in ophthalmology today. The technique has been extensively investigated by the optometric profession, however, sometimes with confusing, and sometimes with useful, results. It can be of value in screening infants for astigmatism and anisometropia, in detecting incomplete cycloplegia, in detecting abnormalities of accommodation, and probably in determining the treatment strategy for eyes with amblyopia and deficient accommodation.

Transposition surgery in childhood strabismus.

Transposition surgery involves an alteration in the mechanical properties of muscle action, such that the direction of movement of the eye following contraction of the muscle is modified. Though often used in the management of more complex motility disorders we have investigated the role of such surgery in concomitant childhood strabismus, and report the results of a computer model prediction and a retrospective review of cases.

Design and evaluation of control strategies for high cell density fermentations.

A methodology for the design and evaluation of bioprocess control strategies is presented. The strategies manage nutrient supply with demand and vary with the metabolic condition and phase of fermentation operation. Six carbon source addition strategies are based on different combinations of available measurements; they are described and evaluated under different operating conditions for yeast cultivation. It is concluded that a single control strategy is not the most appropriate under all possible operating conditions. An oxygen uptake rate-based control strategy performs better with a mean respiratory quotient (RQ) value less than 1.1 during an oxygen limitation than an ethanol control strategy which had a mean RQ of 14. The designed strategies and an approach of applying the strategy that best matches fermentation conditions consistently enables achievement of high cell densities 78.7 g DCW/L and yields 0.50 g DCW/g glucose as the mean values for three fermentations.

External ocular trauma in instrumental and normal deliveries.

OBJECTIVE: To compare the occurrence of external ocular trauma in instrumental and normal deliveries. DESIGN: Prospective controlled study. SETTING: University Hospital of Wales, Cardiff. SUBJECTS: 133 babies born consecutively with the use of forceps and 133 control babies born without instrumentation to women matched for parity. INTERVENTIONS: External ocular examination. MAIN OUTCOME MEASURES: The presence within 24 h of birth of corneal oedema, corneal abrasion, conjunctival chemosis, subconjunctival haemorrhage and lid oedema. RESULTS: Lid oedema and multiple minor external ocular trauma occurred in 52 and 22 babies, respectively, in the instrumental delivery group and in 13 and 8 babies, respectively in the control group (P less than 0.001). Corneal abrasion occurred in two babies and corneal oedema in one baby after forceps delivery but in none of the control group. No more serious injuries occurred. All injuries resolved without long term sequelae. CONCLUSION: The frequency of sight threatening corneal trauma in instrumental deliveries is low. Specialist ophthalmic screening of these babies is not justified.

Recurrent papilloedema and early onset optic atrophy in Behçet's syndrome.

Two patients with Behçet's syndrome and intracranial hypertension are reported. One developed a recurrence of papilloedema while receiving treatment but eventually made a full recovery, whereas the other developed optic atrophy within three months of onset despite treatment.