Parallel probing of drug uptake of single cancer cells on a microfluidic device

Drug resistance is frequently developing during treatment of cancer patients. Intracellular drug uptake is one of the important characteristics to understand mechanism of drug resistance. However, the heterogeneity of cancer cells requires the investigation of drug uptake at the single cell level. Here, we developed a microfluidic device for parallel probing of drug uptake. We combined a v-type valve and peristaltic pumping to select individual cells from a pool of prostate cancer cells (PC3) and place them successively in separate cell chambers in which they were exposed to the drug. Six different concentrations of doxorubicin, a naturally fluorescent anti-cancer drug, were created in loop-shaped reactors and exposed to the cell in closed 2 nL volume chambers. Monitoring every single cell over time in 18 parallel chambers revealed increased intracellular fluorescence intensity according to the dose of doxorubicin, as well as nuclear localization of the fluorescent drug after 2 h of incubation. The herein proposed technology demonstrated a first series of proof of concept experiments and it shows high potential to use for probing drug sensitivity of single cancer cell

Examining the STEM-Science Achievement Test (SSAT) Using Rasch Dichotomous Measurement Model

The main purpose of this study is to develop a valid and reliable instrument for measuring the STEM-Science Achievement Test (SSAT) of primary school students in Malaysia. The instrument was develop by researcher with the integration of STEM elements and by referring to the Malaysia National Curriculum Standard. The development focused on six topics in science Year 4 (Y4) primary syllabus; Scientific Skills, Life Processes of Human, Properties of Materials, Measurement, Solar System, and Importance of Technologies in Life, and six topics in science Year 5 (Y5) primary syllabus; Rules and Regulation in Science Lab, Life Processes of Plants, Acid and Alkali, Electricity, Earth and Space Science, and Technology and Sustainable Life. There are 226 of Year 4 and 226 of Year 5 primary school students in Sabah responded to the instrument developed to test their STEM-Science knowledge. Rasch Dichotomous Measurement Model approach was used to evaluate the validity and reliability of the SSAT. The validity (item polarity (PTMEA-CORR), Principal Component Analysis of Residuals (PCAR), Mean Squared (MNSQ) infit and outfit) and the reliability (Cronbach's alpha, item reliability and item separation) were being assessed. The results Rasch Dichotomous Measurement Model analysis show that all scales were unidimensional for objective and subjective items. For objective items, the Cronbach’s Alpha is .81 (Y4) and .83 (Y5), Item Reliability is .95 (Y4) and .95 (Y5) whereas Item Separation is 4.21 (Y4) and 4.25 (Y5). For item validity, PTMEA CORR were found positive varies between; .03 to .44 (Y4) and .05 to .47 (Y5) after item deletion has been made. Principal Component Analysis of Residuals (PCAR) showed that raw variance explained by measures in Eigenvalue unit is 9.8 (Y4) and 10.7 (Y5), variance unexplained is 60.0 (Y4) and 58.0 (Y5) and variance unexplained in Contrast 1 is 5.1 (Y4) and 3.7 (Y5) respectively. Standardised Residual Correlation for Year 4 and Year 5 objective items showed satisfactory value for none of item correlation exceed control level of .7. There are 5 items misfit in year 4 and 12 item misfit in year 5 objectives test and items need to be revised. For subjective items, the Cronbach’s Alpha is .78 (Y4) and .84 (Y5), item reliability is .91 (Y4) and .93 (Y5) whereas item separation is 3.27 (Y4) and 3.56 (Y5). For item validity, PTMEA CORR were found positive varies between .00 to .50 (Y4) and .01 to .54 (Y5) with no item deletion. Principal Component Analysis of Residuals (PCAR) showed that raw variance explained by measures in Eigenvalue unit is 22.9 (Y4) and 14.1 (Y5), variance unexplained is 96 (Y4) and 70 (Y5) and variance unexplained in Contrast 1 is 4.5 (Y4) and 3.0 (Y5) respectively. Standardised residual correlation for Year 4 and Year 5 subjective items showed satisfactory value for none of item standardised residual correlation exceed control level of .7. The assessment of SSAT has shown that the instrument is a valid and reliable to measure Malaysian primary students’ knowledge in STEM-Science

THE EFFECTS OF WHEELCHAIR CAMBER AND HANDRIM SIZE IN WHEELCHAIR BASKETBALL MOVEMENT

Improving the wheelchair design can be an important determinant of high performance in the wheelchair basketball. Researchers have focused on increasing the efficiency of the wheelchair, looking at the factors such as the seat position, handrim size, and wheel camber. Most handrim and wheel chamber studies, however, have focused only on the propulsive phase. Quick turn as well as fast propulsion is essential to the success in a wheelchair basketball game and the energy efficiency becomes particularly important in a prolonged wheelchair use. The purpose of this study was to investigate the effects of wheelchair camber and handrim size on the linear propulsion, turn velocity, and efficiency

Electric field control of nonvolatile four-state magnetization at room temperature

We find the realization of large converse magnetoelectric (ME) effects at room temperature in a multiferroic hexaferrite Ba$_{0.52}$Sr$_{2.48}$Co$_{2}$Fe$_{24}$O$_{41}$ single crystal, in which rapid change of electric polarization in low magnetic fields (about 5 mT) is coined to a large ME susceptibility of 3200 ps/m. The modulation of magnetization then reaches up to 0.62 $\mu$$_{B}$/f.u. in an electric field of 1.14 MV/m. We find further that four ME states induced by different ME poling exhibit unique, nonvolatile magnetization versus electric field curves, which can be approximately described by an effective free energy with a distinct set of ME coefficients

SUCCESSFUL FACTORS OF 540° DWIHURYEOCHAGI IN TAEKWONDO

The purpose of our study was to provide fundamental information about success factors of 540° Dwihuryeochagi in Taekwondo. Twenty Taekwondo athletes who participated in the 2012 Taekwondo Kyukpa Wang (breaking king) championship: ten successful athletes (S, age: 23.1±1.6 yrs, height: 171.0±3.5 cm, body mass: 66.4±7.1 kg) and ten failed athletes (F, age: 22.3±1.8 yrs, height: 172.1±5.4 cm, body mass: 64.4±4.2 kg) were selected. Three-dimensional motion analysis using a system of 3 video cameras with a sampling of 60 fields/s was performed during the competition of 540 ° Dwihuryeochagi. Based on the findings, it is concluded that success factors of 540° Dwihuryeochagi were horizontal velocity of COM during P1, vertical velocity of COM during P2, and the time, kick distance, velocity and angle of lower extremities of P3-P4

Percutaneous radiofrequency ablation for hepatic tumors: factors affecting baseline impedance

PurposeWe aimed to evaluate factors that affect baseline impedance of percutaneous radiofrequency ablation.MethodsIn this retrospective study, we analyzed 51 patients with 55 hepatic tumors from November 2015 until April 2018. We measured the baseline impedance nine times with three adjustable tip sizes (2 cm, 2.5 cm, 3 cm) and three different pad locations (two pads attached on the thigh, four on the thigh, two on the back). The first roll-off time was measured with two grounding pads attached on the back. Body mass index, cirrhotic or non-cirrhotic liver parenchyma, previous procedure, tumor location, artificial ascites, active tip size, and the pad location were evaluated as potential factors affecting baseline impedance using the Mann–Whitney U test, t-test and analysis of variance test.ResultsComplete radiofrequency ablation was achieved in 51 patients. Body mass index (p = 0.897), cirrhotic or non-cirrhotic liver parenchyma (p = 0.767), previous procedure (p = 0.957), tumor location (p = 0.906), and artificial ascites (p = 0.882) did not significantly affect baseline impedance. Grounding pads located on the back showed the lowest baseline impedance (p < 0.001). Increase in active tip size showed gradual decrease in baseline impedance (p = 0.016).ConclusionThe factors affecting baseline impedance were the pad location and the tip size. Positioning pads on the back lowers the baseline impedance and can shorten the first roll-off time, ultimately resulting in reduced total ablation time

Anticholinesterase Therapy for Patients with Ophthalmoplegia Following Snake Bites: Report of Two Cases

Although ophthalmoplegia following snake bites is not indicative of a serious neurotoxic complication, symptoms of diplopia, dizziness and ocular discomfort can be emotionally devastating for patients. The authors experienced two cases of ophthalmoplegia following snake bites in Korea. The patients complained of diplopia that had developed several hours after the snake bites. The diplopia did not improve with antivenom treatment, but resolved completely after several injections of neostigmine

Strong carrier localization and diminished quantum-confined Stark effect in ultra-thin high-indium-content InGaN quantum wells with violet light emission

Here, we report on the optical and structural characteristics of violet-light-emitting, ultra-thin, high-Indium-content (UTHI) InGaN/GaN multiple quantum wells (MQWs), and of conventional low-In-content MQWs, which both emit at similar emission energies though having different well thicknesses and In compositions. The spatial inhomogeneity of In content, and the potential fluctuation in high-efficiency UTHI MQWs were compared to those in the conventional low-In-content MQWs. We conclude that the UTHI InGaN MQWs are a promising structure for achieving better quantum efficiency in the visible and near-ultraviolet spectral range, owing to their strong carrier localization and reduced quantum-confined Stark effect.open0

Impacts of Comorbidities on the Association between Arterial Stiffness and Obstructive Sleep Apnea in the Elderly

BACKGROUND: Although the impact of obstructive sleep apnea (OSA) on cardiovascular risk is reasonably well established in middle-aged patients, debate persists whether OSA also increases this risk in the elderly. Arterial stiffness has been used as an early independent predictor of cardiovascular risk. STUDY OBJECTIVES: We sought to determine whether OSA had significant effects on the arterial stiffness in the elderly population and evaluate the impacts of comorbidities on the association between arterial stiffness and OSA. METHODS: We performed a cross-sectional study in a university hospital. Elderly participants (≥60 yr) were invited to participate in our study between November 2010 and January 2013. OSA was diagnosed using gold standard polysomnography and arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV) and cardio-ankle vascular index (CAVI) as well as by central systolic and diastolic blood pressure (cSBP and cDBP). High-sensitivity C-reactive protein (hs-CRP) level was also measured. RESULTS: We found no significant association between the severity of OSA and arterial stiffness-related parameters such as cSBP, cDBP, baPWV, CAVI, and hs-CRP. However, in patients without comorbid medical conditions or use of medications (n=101), we showed a modest association between OSA and arterial stiffness-related parameters and hs-CRP. CONCLUSION: We conclude that OSA is associated with increased arterial stiffness in otherwise healthy elderly population, although the association was obviated by comorbidities and medications perhaps due to ceiling effects