Microfluidic active pressure and flow stabiliser

In microfluidics, a well-known challenge is to obtain reproducible results, often constrained by unstable pressures or flow rates. Today, there are existing stabilisers made for low-pressure microfluidics or high-pressure macrofluidics, often consisting of passive membranes, which cannot stabilise long-term fluctuations. In this work, a novel stabilisation method that is able to handle high pressures in microfluidics is presented. It is based on upstream flow capacitance and thermal control of the fluid’s viscosity through a PID controlled restrictor-chip. The stabiliser consists of a high-pressure-resistant microfluidic glass chip with integrated thin films, used for resistive heating. Thereby, the stabiliser has no moving parts. The quality of the stabilisation was evaluated with an ISCO pump, an HPLC pump, and a Harvard pump. The stability was greatly improved for all three pumps, with the ISCO reaching the highest relative precision of 0.035% and the best accuracy of 8.0 ppm. Poor accuracy of a pump was compensated for in the control algorithm, as it otherwise reduced the capacity to stabilise longer times. As the dead volume of the stabiliser was only 16 nL, it can be integrated into micro-total-analysis- or other lab-on-a-chip-systems. By this work, a new approach to improve the control of microfluidic systems has been achieved.

Measurement of macroalgae total carbohydrate content found in Lendang Luar coast, Lombok, Indonesia for potential sources of bioethanol

Bioethanol is a renewable alternative energy through the process of fermenting sugar from carbohydrate sources by adding microorganisms such as yeast or bacteria. Macroalgae or known as seaweed is one of the producers in the marine environment which has a high carbohydrate content so that it can be used as raw material for bioethanol. Macroalgae contains specific carbohydrates including laminarin, mannitol, alginate, agar and polysaccharides. The high carbohydrate content indicates the ethanol content produced. The aim of the study was to initial screen total carbohydrates in red algae (G. latifolium and G rugosa) and brown algae (M rosea, S. crassifolium, S. cristaefolium, S. polycystum, P.australis and T. muray ana). Carbohydrate total analysis was performed by colorimetric assay using the BioVision kit. The overall carbohydrate content found in macroalgae samples in this study was 28.23 fig (DW)1. The highest carbohydrate content was obtained by G. latifolium (37.50 fig (DW)1), followed by G rugosa (34.27 fig (DW)1) and S. cristaefolium (33.33 fig (DW)1). Current results show that macroalgae exhibits sufficient amounts of carbohydrate which could potentially be further developed as source for biotehanol.

Bioanalytical Method Development and Validation of Dapoxetine Hydrochloride in Human Plasma by RP-HPLC

A simple, accurate and rapid Bioanalytical reverse phase high performance liquid chromatography (RPHPLC) method for determination of Dapoxetin hydrochloride in human plasma was validated as per ICH guideline. Dapoxetin hydrochloride is significantly superior in premature ejaculation and more active against serotonin transport inhibitor than any other drug in class. The total analysis was carried out on using stationary phase symmetry C1 (4.6mm X 250mm, 5µm) with Mobile Phase Acetonitrile: Buffer (60:40) pH adjusted to3.5 flow rate was 1.0 ml/min, injection volume of 10 ppm and detection wavelength was 293nm at ambient temperature with total run time of 10 minutes. Retention time of spiked plasma and dapoxetine hydrochloride were found to be 2.153 min and 4.442 min, r2 value were 0.995 and 0.999 and linearity range was 5ppm to 25ppm for both. The method was developed for accuracy, linearity, precision, recovery and stability in complies and stability in complies with CDER and ICH guideline.

Persepsi Mahasiswa FKES UDINUS terkait Hoax Covid-19

Hoax news or information relating to Covid-19 affects the obstruction of efforts to contain the Covid-19 pandemic. This research is a descriptive study because it provides an overview or description of students' perceptions in news related to the covid-19 hoax. The results that obtained information from this study were 208 respondents or 54% of the total respondents considered hoaxes as information with no known truth, 168 respondents or 44% revealed that hoaxes related to Covid-19 were most often found or said to be hoaxes as a global elite conspiracy, 223 respondents or 58% of the total respondents received hoaxes related to Covid-19 through writing and pictures, 162 respondents or 42% of the total respondents considered that steps that could be taken to overcome the spread of hoaxes related to Covid-19 were cross-checking or clarifying first , 317 respondents or 83% thought that each party was responsible for overcoming the spread of hoaxes related to Covid-19 and 150 respondents or 39% of the total analysis that information on social media had a negative influence. The conclusion in this study is that health hoaxes can not only cause disputes like political hoaxes, but can also cause the loss of a person's life. Digital literacy skills will be able to provide hoax. Critical and analytical thinking is also an asset to prevent the spread of covid-19 related to hoaxes

Insights into Student Cognition: Creative Exercises as an Evaluation Tool in Undergraduate First-year Organic Chemistry

It is known that while students can be adept at recalling specific information, especially in end of semester summative exams, they can still often struggle to connect or link this information over different topic areas. In many cases, this issue is exacerbated by traditional assessments and teaching styles that focus on and reward students who have only interacted with the learning materials on a more surface level. Many attempts have been made over time to rectify this, with one such example shown in the use of Creative Exercises (CEs). CEs are open-ended tasks that allow students to connect as much prior knowledge as possible into one cohesive response, potentially developing a student’s ability to link and connect disparate topic areas and content. In this study, CEs were introduced into a large scale first-year course and focused on fundamental organic chemistry reactions for the first time (to the best of our knowledge). Students performed the CEs in groups, and the paper responses were collected over six weeks (N=945 in total). Analysis of these artefacts revealed that students did indeed struggle to connect information over subsequent teaching weeks. This inability to connect information was despite being encouraged to do so both by the tasks and the teaching staff. Additionally, while more ‘advanced’ students (as noted by prior performance) were noted to raise more topics in a given week, they were just as susceptible to ‘siloing’ the information as lower-performing students. Recommendations are made on the future use of CEs.

Keyword Categorization using Statistical Methods

Keyword analysis is a way to gain insight into market behaviour. It is a detailed analysis of words and phrases that are relevant to the selected area. Keyword analysis should be the first step in any search engine optimization, as it reveals what keywords users enter into search engines when searching the Internet. The keyword categorization process takes up almost half of the total analysis time, as it is not automated. There is currently no known tool in the online advertising market that facilitates keyword categorization. The main goal of this paper is to streamline the process of keyword analysis using selected statistical methods of machine learning applied in the categorization of a specific example.

LC-MS/MS Analysis Elucidates a Daily Rhythm in Orexin A Concentration in the Rat Vitreous Body

Orexins are two neuropeptides synthesised mainly in the brain lateral hypothalamic area. The orexinergic system provides arousal-dependent cues for a plethora of brain centres, playing a vital role in feeding behaviour, regulation of the sleep–wake cycle and circadian rhythms. Recently, orexins were found to be produced in the retina of an eye; however, their content in the vitreous body and possible daily pattern of expression have not yet been explored. In this manuscript, we describe the development and validation of a liquid chromatography with tandem mass spectrometry (LC-MS/MS) method designed for quantitative bioanalysis of orexin in the rat vitreous body. Orexin was extracted from vitreous body samples with a water:acetonitrile:formic acid (80:20:0.1; v/v/v) mixture followed by vortexing and centrifuging. Separation was performed on a reverse-phase HPLC column under gradient conditions. Orexin was analysed via multiple-reaction monitoring (MRM) in the positive electrospray mode. The total analysis time for each sample was less than 5.0 min. Once the method was fully optimised, it was then validated, following the 2018 FDA guidance on bioanalytical method validations. The calibration curves for orexin (1–500 ng/mL) were constructed using a linear regression with a 1/x2 weighting. The lower limit of quantitation for orexin was 1.0 pg/mL for the vitreous body. Intra-day and inter-day estimates of accuracy and precision were within 10% of their nominal values, indicating that the method is reliable for quantitation of orexin in the rat vitreous body. From the physiological perspective, our results are the first to show daily rhythm of orexin synthesis by the retina with possible implications on the circadian regulation of vision.

Editorial for the Special Issue on Micro and Nano Devices for Cell Analysis

In recent years, miniaturized systems (micro- and nano-devices) called a lab-on-a-chip or micro-total analysis system (µ-TAS) have received attention as new systems for chemical and biochemical analyses [...]

Oil immersed lossless total analysis system for integrated RNA extraction and detection of SARS-CoV-2

The COVID-19 pandemic exposed difficulties in scaling current quantitative PCR (qPCR)-based diagnostic methodologies for large-scale infectious disease testing. Bottlenecks include lengthy multi-step processes for nucleic acid extraction followed by qPCR readouts, which require costly instrumentation and infrastructure, as well as reagent and plastic consumable shortages stemming from supply chain constraints. Here we report an Oil Immersed Lossless Total Analysis System (OIL-TAS), which integrates RNA extraction and detection onto a single device that is simple, rapid, cost effective, and requires minimal supplies and infrastructure to perform. We validated the performance of OIL-TAS using contrived SARS-CoV-2 viral particle samples and clinical nasopharyngeal swab samples. OIL-TAS showed a 93% positive predictive agreement (n = 57) and 100% negative predictive agreement (n = 10) with clinical SARS-CoV-2 qPCR assays in testing clinical samples, highlighting its potential to be a faster, cheaper, and easier-to-deploy alternative for infectious disease testing.