Integrated DNA extraction and amplification using electrokinetic pumping in a microfluidic device

An integrated system employing anion exchange for the extraction of DNA from biological samples prior to polymerase chain reaction DNA amplification has been developed, based on microfluidic methodology utilising electrokinetic pumping. In this system, the biological samples were added directly to chitosan-coated silica beads to facilitate DNA immobilisation. The purified, pre-concentrated DNA was then eluted using a combination of electro-osmotic flow enhanced with electrophoretic mobility, which enable DNA to be transported by both mechanisms into the DNA amplification chamber. Through optimisation of the DNA elution conditions, average DNA extraction efficiencies of 69.1% were achievable. Subsequent DNA amplification performed on the microfluidic system demonstrated not only the ability to use electrokinetic movement to integrate the two processes on a single device, but also that the quality and quantity of DNA eluted was suitable for downstream analysis. This work offers an attractive real-world to chip interface and a route to simpler Lab-on-a-Chip technology which eliminates the need for moving parts.

Direct processing of clinically relevant large volume samples for the detection of sexually transmitted infectious agents from urine on a microfluidic device

Urine is a preferred specimen for nucleic acid-based detection of sexually transmitted infections (STIs) but represents a challenge for microfluidic devices due to low analyte concentrations. We present an extraction methodology enabling rapid on-chip nucleic acid purification directly from clinically relevant sample volumes up to 1 ml and subsequent PCR amplification detection.

Design and properties of a new hybrid stent-graft device

This PhD work explored a novel bio-inspired approach for designing artificial blood vessel implants known as stent-grafts. The design was inspired from body design of a caterpillar. This design concept induced natural flexibility and expandability property in the new stent-graft, which is considered critical in deciding long-term health of treated patients.

RF rectifiers for EM power harvesting in a deep brain stimulating device

A passive deep brain stimulation (DBS) device can be equipped with a rectenna, consisting of an antenna and a rectifier, to harvest energy from electromagnetic fields for its operation. This paper presents optimization of radio frequency rectifier circuits for wireless energy harvesting in a passive head-mountable DBS device. The aim is to achieve a compact size, high conversion efficiency, and high output voltage rectifier. Four different rectifiers based on the Delon doubler, Greinacher voltage tripler, Delon voltage quadrupler, and 2-stage charge pumped architectures are designed, simulated, fabricated, and evaluated. The design and simulation are conducted using Agilent Genesys at operating frequency of 915 MHz. A dielectric substrate of FR-4 with thickness of 1.6 mm, and surface mount devices (SMD) components are used to fabricate the designed rectifiers. The performance of the fabricated rectifiers is evaluated using a 915 MHz radio frequency (RF) energy source. The maximum measured conversion efficiency of the Delon doubler, Greinacher tripler, Delon quadrupler, and 2-stage charge pumped rectifiers are 78, 75, 73, and 76 % at -5 dBm input power and for load resistances of 5-15 kΩ. The conversion efficiency of the rectifiers decreases significantly with the increase in the input power level. The Delon doubler rectifier provides the highest efficiency at both -5 and 5 dBm input power levels, whereas the Delon quadrupler rectifier gives the lowest efficiency for the same inputs. By considering both efficiency and DC output voltage, the charge pump rectifier outperforms the other three rectifiers. Accordingly, the optimised 2-stage charge pumped rectifier is used together with an antenna to harvest energy in our DBS device.

The association between use of antidepressants and bone quality using quantitative heel ultrasound.

Osteoporosis and depression are major public health problems worldwide. Studies have reported an association between antidepressant use, mainly selective serotonin reuptake inhibitors (SSRIs), and bone mineral density (BMD), but the issue remains unclear.

Aortic intima-media thickness measured by trans-abdominal ultrasound as an early life marker of subclinical atherosclerosis

Atherosclerosis is a chronic inflammatory process that begins in early life. Improved identification of markers of early atherosclerosis via neonatal aortic intima-media thickness (aIMT) measurement may allow the development of interventions to prevent or reduce later cardiovascular disease.

Five ways to hack and cheat with bring-your-own-device electronic examinations

Bring-your-own-device electronic examinations (BYOD e-exams) are a relatively new type of assessment where students sit an in-person exam under invigilated conditions with their own laptop. Special software restricts student access to prohibited computer functions and files, and provides access to any resources or software the examiner approves. In this study, the decades-old computer security principle that ‘software security depends on hardware security’ is applied to a range of BYOD e-exam tools. Five potential hacks are examined, four of which are confirmed to work against at least one BYOD e-exam tool. The consequences of these hacks are significant, ranging from removal of the exam paper from the venue through to receiving live assistance from an outside expert. Potential mitigation strategies are proposed; however, these are unlikely to completely protect the integrity of BYOD e-exams. Educational institutions are urged to balance the additional affordances of BYOD e-exams for examiners against the potential affordances for cheaters.

Parents' perspectives on tele-AAC support for families with a new speech generating device: results from an Australian pilot study

Telepractice is rapidly gaining popularity as a cost-effective and convenient alternative to in-person services for a range of speech-language pathology (SLP) applications. To date, there has been little research investigating the use of telepractice to support families with a new speech generating device (SGD). This paper reports on the outcomes of a novel online training and support program, trialed with 4 underserviced Australian families of children with a new SGD. The program consisted of 6 video-narrated lessons on SGD use, along with an online supervision and practice component conducted via videoconference. Semistructured interviews were undertaken with parents following their completion of the program. Parents noted the telepractice support model offered a range of benefits, including convenient service access and flexible learning options. Challenges included technology limitations and increased pressure on parents to coordinate home practice. Overall, parents reported that the telepractice program was a positive experience for them and their children. Findings indicated that telepractice is a promising mode of service delivery for those learning to use a new SGD. Further research in this area is warranted.

Improvement of light harvesting and device performance of dye-sensitized solar cells using rod-like nanocrystal TiO2 overlay coating on TiO2 nanoparticle working electrode

Novel TiO2 single crystalline nanorods were synthesized by electrospinning and hydrothermal treatment. The role of the TiO2 nanorods on TiO2 nanoparticle electrode in improvement of light harvesting and photovoltaic properties of dye-sensitized solar cells (DSSCs) was examined. Although the TiO2 nanorods had lower dye loading than TiO2 nanoparticle, they showed higher light utilization behaviour. Electron transfer in TiO2 nanorods received less resistance than that in TiO2 nanoparticle aggregation. By just applying a thin layer of TiO2 nanorods on TiO2 nanoparticle working electrode, the DSSC device light harvesting ability and energy conversion efficiency were improved significantly. The thickness of the nanorod layer in the working electrode played an important role in determining the photovoltaic property of DSSCs. An energy conversion efficiency as high as 6.6% was found on a DSSC device with the working electrode consisting of a 12 μm think TiO2 nanoparticle layer covered with 3 μm thick TiO2 nanorods. The results obtained from this study may benefit further design of highly efficient DSSCs.

Development of a compact rectenna for wireless powering of a head-mountable deep brain stimulation device

Design of a rectangular spiral planar inverted-F antenna (PIFA) at 915 MHz for wireless power transmission applications is proposed. The antenna and rectifying circuitry form a rectenna, which can produce dc power from a distant radio frequency energy transmitter. The generated dc power is used to operate a low-power deep brain stimulation pulse generator. The proposed antenna has the dimensions of 10 mm × 12.5 mm × 1.5 mm and resonance frequency of 915 MHz with a measured bandwidth of 15 MHz at return loss of -10 dB. A dielectric substrate of FR-4 of εr = 4.8 and δ = 0.015 with thickness of 1.5 mm is used for both antenna and rectifier circuit simulation and fabrication because of its availability and low cost. An L-section impedance matching circuit is used between the PIFA and voltage doubler rectifier. The impedance matching circuit also works as a low-pass filter for elimination of higher order harmonics. Maximum dc voltage at the rectenna output is 7.5 V in free space and this rectenna can drive a deep brain stimulation pulse generator at a distance of 30 cm from a radio frequency energy transmitter, which transmits power of 26.77 dBm.