A monolithic silicon based integrated signal generation and detection system for monitoring DNA hybridisation.

The aim of this work was to develop an integrated solution to DNA hybridisation monitoring for diagnostics on a monolithic silicon platform. A fabrication process was developed incorporating a gold initiation electrode patterned directly onto a PIN photodiode detector. Patterned interdigitated type electrodes exhibited the smallest reduction in photodiode sensitivity, therefore these were chosen as the ECL initiator design. A novel DNA hybridisation assay was developed based on the displacement of a partially mismatched complementary strand by a perfectly matched labelled complementary strand. Pre-hybridised thiolated oligonucleotide and unlabelled 25% mismatched oligonucleotide were assembled on the gold initiation electrode. On addition of the labelled perfectly complementary oligonucleotide, the mismatched strands were displaced and a signal was generated. The sensitivity of the photodiode to light emitted at 620 nm, the ruthenium emission wavelength, was determined and subsequently, the diode current response to light generated by flow addition of ruthenium solution was found to be measurable to a concentration of 10 fM. Pre-hybridised duplex DNA, consisting of thiolated oligonucleotide and ruthenium labelled complementary oligonucleotide, was assembled on the gold initiation electrode. The difference between the current measured during flow of buffer and the ECL co-reactant TPA was three orders of magnitude, indicating that DNA assembled on the surface comprised sufficient ruthenium to generate a measurable signal. Finally, the displacement of unlabelled partial mismatch oligonucleotide from the sensor surface was monitored on addition of the ruthenium labelled perfectly complementary oligonucleotide in TPA flow and the measured photodiode current response was up to 50 times greater.

Bruising frequency and patterns in children with physical disabilities.

OBJECTIVE: We obtained normative data on bruising in children with physical disability in functioning and evaluated factors associated with bruising in this population. METHODS: We studied children with physical and/or cognitive disabilities who attend a school that provides comprehensive services. Over a 15-month period, the children had skin examinations, including external inspection of the genitalia and anus. For each child, we gathered information on demographics, medications, growth measures, medical conditions, equipment used, and muscle tone. Functional independence in basic mobility, self-care, and social communication was assessed by using the Functional Independence Measure for Children (WeeFIM). Results were compared with a previously studied nondisabled or "typical" population of children. RESULTS: Fifty children and adolescents 4 to 20 years of age had 2 skin examinations. There was no relationship between the number of bruises and the child's age, race, or BMI. Overall, our subjects were more likely to have at least 1 bruise noted than nondisabled children from a comparable study. There was no significant relationship between the number of bruises and functional mobility, self-care, cognition, or muscle tone. The bruising locations in our study group were different from those of nondisabled children. However, in both groups bruises were rarely found on the neck, ears, chin, anterior chest, or buttocks. CONCLUSIONS: The children in our study were different from nondisabled children in the frequency and pattern of their bruising. Areas uncommonly bruised in typical children were also uncommonly bruised in the disabled children. Although increasing age and mobility clearly make a difference in the number of bruises a typically functioning child sustains, these factors are not relevant when evaluating bruises on a child with disabilities. Other factors such as muscle tone, cognition, and equipment should be considered when evaluating a child with significant disabilities who presents with bruises.