Miniature LED Research Articles

The development of chemistry students’ 21 century skills through a STEAM project on electrolyte and non-electrolyte solutions

This paper portrays a study into the integration of a Science, Technology, Art, Engineering, and Mathematics (STEAM) project in chemistry learning of electrolyte non-electrolyte solutions for developing 21st-century skills. Thirty-two, year-10 students engaged in the study. The research employed qualitative methodology with multiple modes of data collection via semi-structured interviews; classroom observations, reflective journals, and documentation were guided by a 21st-century skills rubric. In addition, the project was assessed against the criteria of project development, STEAM integration, and product quality. Students designed an innovative project, integrating STEAM in developing and making a miniature LED by using the natural electrolyte solution sources, such as lemon, lime, apples, and salt water. Students created posters and video projects for presentation in a project exhibition. Students were able to integrate their knowledge from various fields to solve problems and create new innovations. The students used the 21st-century skills of collaboration, communication, critical thinking, creativity and innovation alongside technology as a tool for learning. The engaging learning environment encouraged students to develop their skills and chemistry conceptual understanding.

Visualizing Phonotactic Behavior of Female Frogs in Darkness

Many animals use sounds produced by conspecifics for mate identification. Female insects and anuran amphibians, for instance, use acoustic cues to localize, orient toward and approach conspecific males prior to mating. Here we present a novel technique that utilizes multiple, distributed sound-indication devices and a miniature LED backpack to visualize and record the nocturnal phonotactic approach of females of the Australian orange-eyed tree frog (Litoria chloris) both in a laboratory arena and in the animal’s natural habitat. Continuous high-definition digital recording of the LED coordinates provides automatic tracking of the female’s position, and the illumination patterns of the sound-indication devices allow us to discriminate multiple sound sources including loudspeakers broadcasting calls as well as calls emitted by individual male frogs. This innovative methodology is widely applicable for the study of phonotaxis and spatial structures of acoustically communicating nocturnal animals.

Application of UV absorbance and fluorescence indicators to assess the formation of biodegradable dissolved organic carbon and bromate during ozonation

This study examined the significance of changes of UV absorbance and fluorescence of dissolved organic matter (DOM) as surrogate indicators for assessing the formation of bromate and biodegradable dissolved organic carbon (BDOC) during the ozonation of surface water and wastewater effluent. Spectroscopic monitoring was carried out using benchtop UV/Vis and fluorescence spectrophotometers and a newly developed miniature LED UV/fluorescence sensor capable of rapidly measuring UVA280 and protein-like and humic-like fluorescence. With the increase of O3/DOC mass ratio, the plots of BDOC formation were characterized of initial lag, transition slope and final plateau. With the decrease of UV absorbance and fluorescence, BDOC concentrations initially increased slowly and then rose more noticeably. Inflection points in plots of BDOC versus changes of spectroscopic indicators were close to 35–45% loss of UVA254 or UVA280 and 75–85% loss of humic-like fluorescence. According to the data from size exclusion chromatography (SEC) with organic carbon detection and 2D synchronous correlation analyses, DOM fractions assigned to operationally defined large biopolymers (apparent molecular weight, AMW>20 kDa) and medium AMW humic substances (AMW 5.5–20 kDa) were transformed into medium-size building blocks (AMW 3–5.5 kDa) and other smaller AMW species (AMW<3 kDa) associated with BDOC at increasing O3/DOC ratios. Appreciable bromate formation was observed only after the values of UVA254, UVA280 and humic-like fluorescence in O3-treated samples were decreased by 45–55%, 50–60% and 86–92% relative to their respective initial levels. No significant differences in plots of bromate concentrations versus decreases of humic-like fluorescence were observed for surface water and wastewater effluent samples. This was in contrast with the plots of bromate concentration versus UVA254 and UVA280 which exhibited sensitivity to varying initial bromide concentrations in the investigated water matrixes. These results suggest that measurements of humic-like fluorescence can provide a useful supplement to UVA indices for characterization of ozonation processes.

The AirScope: A Novel Wireless Laparoscope

The modern laparoscope relies on Hopkins’ glass rod lenses, a fiber-optic light source, a video camera, and external cables. This paper discusses the feasibility of developing an experimental prototype of a completely wireless laparoscope by making use of the latest in electronic and optic miniaturization. Design requirements were defined to mimic a standard 10 mm adult laparoscope. An 8 mm diameter (CMOS) camera was used, which delivered standard definition TV resolution at an image refresh rate of 30 Hz. A wide-angle lens was chosen, and a focusing mechanism was designed. Instead of a fiber-optic cable, illumination was achieved using four miniature LED lights. A 2.4 GHz wireless transmission with adequate range for use in an operating theater was chosen. A wireless receiver on a standard personal computer was used to drive a video monitor using off the shelf image processing software. A built-in rechargeable battery powered the wireless laparoscope. Flicker-free in vitro wireless video transmission was achieved. The laparoscope was made waterproof with a front cover lens and can be gas or chemically sterilized. The prototype laparoscope weights 78 g as compared with 900 g for a typical 10 mm laparoscope, camera, fiber-optic, and camera cables. Drawbacks of the prototype include reduced resolution of the video image as compared to high definition (HD) TV quality available on the most recent commercial camera systems. This experimental prototype has illustrated the feasibility of wireless endoscopy systems. The expected benefits include improved ergonomic maneuverability, reduced weight, and decreased electric power requirements.

Selective viral transduction of adult-born olfactory neurons for chronic in vivo optogenetic stimulation.

Local interneurons are continuously regenerated in the olfactory bulb of adult rodents. In this process, called adult neurogenesis, neural stem cells in the walls of the lateral ventricle give rise to neuroblasts that migrate for several millimeters along the rostral migratory stream (RMS) to reach and incorporate into the olfactory bulb. To study the different steps and the impact of adult-born neuron integration into preexisting olfactory circuits, it is necessary to selectively label and manipulate the activity of this specific population of neurons. The recent development of optogenetic technologies offers the opportunity to use light to precisely activate this specific cohort of neurons without affecting surrounding neurons. Here, we present a series of procedures to virally express Channelrhodopsin2(ChR2)-YFP in a temporally restricted cohort of neuroblasts in the RMS before they reach the olfactory bulb and become adult-born neurons. In addition, we show how to implant and calibrate a miniature LED for chronic in vivo stimulation of ChR2-expressing neurons.

An integrated portable hand-held analyser for real-time isothermal nucleic acid amplification

A compact hand-held heated fluorometric instrument for performing real-time isothermal nucleic acid amplification and detection is described. The optoelectronic instrument combines a Printed Circuit Board/Micro Electro Mechanical Systems (PCB/MEMS) reaction detection/chamber containing an integrated resistive heater with attached miniature LED light source and photo-detector and a disposable glass waveguide capillary to enable a mini-fluorometer. The fluorometer is fabricated and assembled in planar geometry, rolled into a tubular format and packaged with custom control electronics to form the hand-held reactor. Positive or negative results for each reaction are displayed to the user using an LED interface. Reaction data is stored in FLASH memory for retrieval via an in-built USB connection. Operating on one disposable 3 V lithium battery >12, 60 min reactions can be performed. Maximum dimensions of the system are 150 mm ( h) × 48 mm ( d) × 40 mm ( w), the total instrument weight (with battery) is 140 g. The system produces comparable results to laboratory instrumentation when performing a real-time nucleic acid sequence-based amplification (NASBA) reaction, and also displayed comparable precision, accuracy and resolution to laboratory-based real-time nucleic acid amplification instrumentation. A good linear response ( R 2 = 0.948) to fluorescein gradients ranging from 0.5 to 10 μM was also obtained from the instrument indicating that it may be utilized for other fluorometric assays. This instrument enables an inexpensive, compact approach to in-field genetic screening, providing results comparable to laboratory equipment with rapid user feedback as to the status of the reaction.