The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA. In this current work, we demonstrate a novel method of DNA-based identification of basidiomycetes using current-voltage (I-V) profiles obtained from DNA-specific Schottky barrier diodes. Electronic properties such as ideality factor, barrier height, shunt resistance, series resistance, turn-on voltage, knee-voltage, breakdown voltage and breakdown current were calculated and used to quantify the identification process as compared to morphological and molecular characterization techniques. The use of these techniques is necessary in order to study biodiversity, but sometimes it can be misleading and unreliable and is not sufficiently useful for the identification of fungi genera. Many of these methods have failed when it comes to identification of closely related species of certain genus like Pleurotus. Our electronics profiles, both in the negative and positive bias regions were however found to be highly characteristic according to the base-pair sequences. We believe that this simple, low-cost and practical method could be useful towards identifying and detecting DNA in biotechnology and pathology.
HIV risk behaviors and psychological well-being among men who have sex with men (MSM) in Kuala Lumpur, Malaysia (n = 140), were quantitatively described in relation to demographic and psychosocial factors. Most participants were tested for HIV and 41.4% reported living with HIV. Malay participants had significantly higher levels of depression (p < .05), homophobia (p < .01), and needs for social support (p < .01) than Chinese. More Chinese participants reported suicidal thoughts than Malaysians (p < .05). A multivariate analysis revealed that participants with gay/MSM-identified or had lower levels of self-esteem showed significantly higher levels of depression. Future intervention projects should address depression and mental health issues among MSM and strengthen self-esteem and social support through culturally competent support and individual counseling programs (e.g., addressing MSM's conflicts with religious beliefs and norms). Structural changes must be made incrementally to reduce homophobia against MSM in Malaysia while advocating human rights.
Conventional three-electrode systems used in electrochemical measurement demand time-consuming and maintenance intensive procedures to enable accurate and repeatable electrochemical measurements. Traditionally, different metal configurations are used to establish the electrochemical gradient required to acquire the redox activity, and vary between different electrochemical measurement platforms. However, in this work, we report using the same metal (gold) for the counter, working and reference electrodes fabricated on a miniaturized printed circuit board (PCB) for a much simpler design. Potassium ferricyanide, widely used as a redox probe for electrochemical characterization, was utilized to acquire cyclic voltametric profiles using both the printed circuit board-based gold-gold-gold three-electrode and conventional three-electrode systems (glassy carbon electrode or graphite foil as the working electrode, platinum wire as the counter electrode, and Ag/AgCl as the reference electrode). The results show that both types of electrode systems generated similar cyclic voltammograms within the same potential window (-0.5 to +0.7 V). However, the novel PCB-based same-metal three-electrode electrochemical cell only required a few activation cycles and exhibited impressive cyclic voltametric repeatability with higher redox sensitivity and detection window, while using only trace amounts of solutions/analytes.
The exciting discovery of the semiconducting-like properties of deoxyribonucleic acid (DNA) and its potential applications in molecular genetics and diagnostics in recent times has resulted in a paradigm shift in biophysics research. Recent studies in our laboratory provide a platform towards detecting charge transfer mechanism and understanding the electronic properties of DNA based on the sequence-specific electronic response, which can be applied as an alternative to identify or detect DNA. In this study, we demonstrate a novel method for identification of DNA from different shrimp viruses and bacteria using electronic properties of DNA obtained from both negative and positive bias regions in current-voltage (I-V) profiles. Characteristic electronic properties were calculated and used for quantification and further understanding in the identification process. Aquaculture in shrimp industry is a fast-growing food sector throughout the world. However, shrimp culture in many Asian countries faced a huge economic loss due to disease outbreaks. Scientists have been using specific established methods for detecting shrimp infection, but those methods do have their significant drawbacks due to many inherent factors. As such, we believe that this simple, rapid, sensitive and cost-effective tool can be used for detection and identification of DNA from different shrimp viruses and bacteria.