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1.
Chemistry ; : e202401023, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38807442

ABSTRACT

Flexible optoelectronics is the need of the hour as the market moves toward wearable and conformable devices. Crystalline π-conjugated materials offer high performance as active materials compared to their amorphous counterpart, but they are typically brittle. This poses a significant challenge that needs to be overcome to unfold their potential in optoelectronic devices. Unveiling the molecular packing topology and identifying interaction descriptors that can seamlessly accommodate strain offers essential guiding principles for developing conjugated materials as active components in flexible optoelectronics. The molecular packing and interaction topology of eight crystal systems of dicyano-distyrylbenzene derivatives are investigated. Face-to-face π-stacks in an inclined orientation relative to the bending surface can accommodate expansion and compression with minimal molecular motion from their equilibrium positions. This configuration exhibits good compliance towards mechanical strain, while a similar structure with a criss-cross arrangement capable of distributing applied strain equally in opposite directions enhances the flexibility. Molecular arrangements that cannot reversibly undergo expansion and compression exhibit brittleness. In the isometric CT crystals, the disproportionate strength of the interactions along the bending plane and orthogonal directions makes these materials sustain a moderate bending strain. These results provide an updated explanation for the elastic bending in semiconducting π-conjugated crystals.

2.
Epidemiol Health ; : e2024036, 2024 Mar 07.
Article in English | MEDLINE | ID: mdl-38514199

ABSTRACT

Objectives: Salmonellosis outbreaks occurred at 2 restaurants 2 days apart, and an epidemiological investigation was conducted to determine whether the outbreaks were connected. Methods: Case studies were conducted for both outbreaks. Stool samples were collected from individuals, and food samples were collected from the restaurants. Pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing analyses were performed on outbreak-related Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) isolates. Traceback investigations were also conducted for the ingredients from gimbap restaurants A and B. Results: In total, 106 people from gimbap restaurant A and 5 from gimbap restaurant B met the case definition. Salmonella Enteritidis was detected in samples from 2 food handlers, 22 patients, and 1 food (iceberg lettuce) at gimbap restaurant A and from 1 patient at gimbap restaurant B. According to PFGE, all isolates were identified as SEGX01.089. The molecular typing of all isolates showed the same pattern, and the genetic distance was close according to phylogenetic analysis. Eggs were the only food ingredient that was supplied to both gimbap restaurants. Conclusion: The outbreaks were caused by Salmonella Enteritidis, and the source of infections was suspected to be contaminated eggs. To prevent foodborne outbreaks of Salmonella, restaurants should heat eggs sufficiently, and egg farms need to establish management systems that prevent Salmonella infections.

3.
Cell ; 187(3): 609-623.e21, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38244548

ABSTRACT

Phosphatidic acid (PA) and reactive oxygen species (ROS) are crucial cellular messengers mediating diverse signaling processes in metazoans and plants. How PA homeostasis is tightly regulated and intertwined with ROS signaling upon immune elicitation remains elusive. We report here that Arabidopsis diacylglycerol kinase 5 (DGK5) regulates plant pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). The pattern recognition receptor (PRR)-associated kinase BIK1 phosphorylates DGK5 at Ser-506, leading to a rapid PA burst and activation of plant immunity, whereas PRR-activated intracellular MPK4 phosphorylates DGK5 at Thr-446, which subsequently suppresses DGK5 activity and PA production, resulting in attenuated plant immunity. PA binds and stabilizes the NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD), regulating ROS production in plant PTI and ETI, and their potentiation. Our data indicate that distinct phosphorylation of DGK5 by PRR-activated BIK1 and MPK4 balances the homeostasis of cellular PA burst that regulates ROS generation in coordinating two branches of plant immunity.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Diacylglycerol Kinase , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Diacylglycerol Kinase/metabolism , NADPH Oxidases/metabolism , Phosphatidic Acids/metabolism , Phosphorylation , Plant Immunity , Protein Serine-Threonine Kinases/metabolism , Reactive Oxygen Species/metabolism , Receptors, Pattern Recognition/metabolism
4.
Micromachines (Basel) ; 14(9)2023 Sep 14.
Article in English | MEDLINE | ID: mdl-37763929

ABSTRACT

Selective laser etching is a promising candidate for the mass production of glass interposers. It comprises two steps: local modification by an ultrashort-pulsed laser and chemical etching of the modified volume. According to previous studies, when an ultrashort-pulsed laser beam is irradiated on the sample, electron excitation occurs, followed by phonon vibration. In general, the electron excitation occurs for less than a few tens of picoseconds and phonon vibration occurs for more than 100 picoseconds. Thus, in order to compare the electric absorption and thermal absorption of photons in the commercial glass, we attempt to implement an additional laser pulse of 213 ps and 10 ns after the first pulse. The modified glass sample is etched with 8 mol/L KOH solution with 110 °C to verify the effect. Here, we found that the electric absorption of photons is more effective than the thermal absorption of them. We can claim that this result helps to enhance the process speed of TGV generation.

5.
Methods Mol Biol ; 2690: 101-110, 2023.
Article in English | MEDLINE | ID: mdl-37450140

ABSTRACT

The characterization of protein-protein interactions (PPI) often provides functional information about a target protein. Yeast-two-hybrid (Y2H) and luminescence/fluorescence-based detections, therefore, have been widely utilized for assessing PPI. In addition, a co-immunoprecipitation (co-IP) method has also been adopted with transient protein expression in Nicotiana benthamiana (N. benthamiana) infiltrated with Agrobacterium tumefaciens. Herein, we describe a co-IP procedure in which structural maintenance of chromosome 1 (SMC1), identified from a Y2H screening, was verified as an interacting partner for microchidia 1 (MORC1), a protein well known for its function in plant immunity and epigenetics. SMC1 and MORC1 were transiently expressed in N. benthamiana when infiltrated by Agrobacterium with the respective genes. From this approach, we identified a region of SMC1 responsible for interacting with MORC1. The co-IP method, of which outputs are mainly from immunoblot analysis, provided information about target protein expression as well, which is often useful for troubleshooting. Using this feature, we showcased a PPI confirmation from our SMC1-MORC1 study in which a full-length SMC1 protein was not detectable, and, therefore, a subsequent truncated mutant analysis had to be employed for PPI verification.


Subject(s)
Nicotiana , Proteins , Nicotiana/metabolism , Proteins/metabolism , Agrobacterium tumefaciens/genetics , Staphylococcal Protein A/metabolism , Immunoprecipitation
6.
Br J Educ Psychol ; 93(4): 1207-1223, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37430428

ABSTRACT

BACKGROUND: A controversy over the distinction between curiosity and situational interest has recently resurfaced. Nonetheless, empirical research comparing the two is noticeably lacking. AIMS: We attempted to fill this gap and provide much-needed evidence of the distinction between curiosity and situational interest by examining the antecedents and consequences of the two constructs. METHODS: We assessed enjoyment, novelty, uncertainty and surprise as potential antecedents and information seeking, individual interest, career intention and achievement as potential outcomes of curiosity and situational interest among 219 Korean sixth graders in the domain of science. RESULTS: Of the hypothesized antecedents, enjoyment during science class related most strongly to students' situational interest in science, whereas novelty in science class related most strongly to students' science curiosity. Uncertainty and surprise in science class related to only science curiosity and not situational interest in science. Among the outcomes considered, situational interest in science related to only students' individual interest in science. In comparison, science curiosity related significantly to all science outcomes measured in this study. Science curiosity also significantly mediated the relationships between the antecedents and outcomes in science. CONCLUSIONS: Together, these results support the distinction between curiosity and situational interest and suggest different ways to promote each motivation construct depending on desired outcomes in the science classroom.


Subject(s)
Exploratory Behavior , Motivation , Humans , Achievement , Intention , Students
7.
Cell ; 186(11): 2329-2344.e20, 2023 05 25.
Article in English | MEDLINE | ID: mdl-37192618

ABSTRACT

Enabling and constraining immune activation is of fundamental importance in maintaining cellular homeostasis. Depleting BAK1 and SERK4, the co-receptors of multiple pattern recognition receptors (PRRs), abolishes pattern-triggered immunity but triggers intracellular NOD-like receptor (NLR)-mediated autoimmunity with an elusive mechanism. By deploying RNAi-based genetic screens in Arabidopsis, we identified BAK-TO-LIFE 2 (BTL2), an uncharacterized receptor kinase, sensing BAK1/SERK4 integrity. BTL2 induces autoimmunity through activating Ca2+ channel CNGC20 in a kinase-dependent manner when BAK1/SERK4 are perturbed. To compensate for BAK1 deficiency, BTL2 complexes with multiple phytocytokine receptors, leading to potent phytocytokine responses mediated by helper NLR ADR1 family immune receptors, suggesting phytocytokine signaling as a molecular link connecting PRR- and NLR-mediated immunity. Remarkably, BAK1 constrains BTL2 activation via specific phosphorylation to maintain cellular integrity. Thus, BTL2 serves as a surveillance rheostat sensing the perturbation of BAK1/SERK4 immune co-receptors in promoting NLR-mediated phytocytokine signaling to ensure plant immunity.


Subject(s)
Arabidopsis , Plant Immunity , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Protein Kinases/genetics , Protein Serine-Threonine Kinases/genetics , Receptors, Pattern Recognition , Signal Transduction
8.
Micromachines (Basel) ; 13(8)2022 Aug 17.
Article in English | MEDLINE | ID: mdl-36014253

ABSTRACT

A miniaturized pump to manipulate liquid flow in microchannels is the key component of microfluidic devices. Many researchers have demonstrated active microfluidic pumps, but most of them still required additional large peripherals to operate their micropumps. In addition, those micropumps were made of polymer materials so that their application may be limited to a variety of fields that require harsh conditions at high pressures and temperatures or organic solvents and acid/base. In this work, we present a 3D miniaturized magnetic-driven glass centrifugal pump for microfluidic devices. The pump consists of a volute structure and a 3D impeller integrated with two magnet disks of Φ1 mm. The 3D pump structure was 13 mm × 10.5 mm × 3 mm, and it was monolithically fabricated in a fused silica sheet by selective laser-induced etching (SLE) technology using a femtosecond laser. The pump operation requires only one motor rotating two magnets. It was Φ42 mm × 54 mm and powered by a battery. To align the shaft of the motor to the center of the 3D glass pump chip, a housing containing the motor and the chip was fabricated, and the overall size of the proposed micropump device was 95 mm × 70 mm × 75 mm. Compared with other miniaturized pumps, ours was more compact and portable. The output pressure of the fabricated micropump was between 215 Pa and 3104 Pa, and the volumetric flow rate range was 0.55 mL/min and 7.88 mL/min. The relationship between the motor RPM and the impeller RPM was analyzed, and the flow rate was able to be controlled by the RPM. With its portability, the proposed pump can be applied to produce an integrated and portable microfluidic device for point-of-care analysis.

9.
Front Psychol ; 13: 830462, 2022.
Article in English | MEDLINE | ID: mdl-35250773

ABSTRACT

We used functional magnetic resonance imaging to examine the interactive effects of perceived competence and task interest on the cognitive and affective responses to negative feedback. Twenty-four undergraduates performed both interesting and uninteresting tasks and received failure feedback. The participants' perceived competence in the task was manipulated between subjects prior to scanning with bogus feedback. The results showed that negative feedback processing was contingent upon both perceived competence and task interest. The most adaptive coping mechanism, indicated by activation in the cognitive control network and attenuation in the negative affect region, was identified for the high-competence and high-interest combination. When either competence or interest was low, signals in the cognitive control network were weaker. The most detrimental activation patterns were observed for the combination of low-competence and high interest. Our results reveal the combination of task and learner characteristics that best harnesses the potential benefits of negative feedback and illustrate the neuroscientific mechanisms underlying this observation.

10.
Micromachines (Basel) ; 13(2)2022 Feb 21.
Article in English | MEDLINE | ID: mdl-35208463

ABSTRACT

This study proposes a rapid and inexpensive thermocycler that enables rapid heating of samples using a thin glass chip and a cheap chip resistor to overcome the on-site diagnostic limitations of polymerase chain reaction (PCR). Microchip PCR devices have emerged to miniaturize conventional PCR systems and reduce operation time and cost. In general, PCR microchips require a thin-film heater fabricated through a semiconductor process, which is a complicated process, resulting in high costs. Therefore, this investigation substituted a general chip resistor for a thin-film heater. The proposed thermocycler consists of a compact glass microchip of 12.5 mm × 12.5 mm × 2 mm that could hold a 2 µL PCR sample and a surface-mounted chip resistor of 6432 size (6.4 mm × 3.2 mm). Improving heat transfer from the chip resistor heater to the PCR reaction chamber in the microchip was accomplished via the design and fabrication of a three-dimensional chip structure using selective laser-induced etching, a rapid prototyping technique that allowed to be embedded. The fabricated PCR microchip was combined with a thermistor temperature sensor, a blower fan, and a microcontroller. The assembled thermocycler could heat the sample at a maximum rate of 28.8 °C/s per second. When compared with a commercially available PCR apparatus running the same PCR protocol, the total PCR operating time with a DNA sample was reduced by about 20%.

11.
ACS Nano ; 15(12): 20300-20310, 2021 Dec 28.
Article in English | MEDLINE | ID: mdl-34783245

ABSTRACT

Despite extensive efforts to explore femtosecond lasers functionalized by nonlinear graphene (Gf) that relies on the traditional transfer process, maximizing the efficiency, customizing the nonlinear interaction, and minimizing the optical loss remain critical challenges, especially in high-energy pulse generation. We demonstrate an ultrafast nonlinear all-fiber device based on conformal Gf directly synthesized in three dimensions on the surface of an in-fiber microstructure. A femtosecond laser-induced selective etching process is used to fabricate a customized microstructure that ensures the minimum but efficient laser-Gf interaction as well as possesses excellent surface conditions to suppress absorption and scattering loss. Conformal Gf is prepared by a spatial diffusion-based atomic carbon spraying process that enables nanocrystals to be synthesized homogeneously even onto the complex surface of the microstructure. The demonstration of high-energy pulses from the Gf saturable absorber highlights its simple, process-efficient, adjustable, and robust performance. The resultant hyperbolic secant pulses display individual pulse energy and peak power of up to 13.2 nJ and 20.17 kW, respectively.

12.
Opt Express ; 29(22): 35261-35270, 2021 Oct 25.
Article in English | MEDLINE | ID: mdl-34808964

ABSTRACT

We fabricate three-dimensional wavelength-division multiplexing (3D-WDM) interconnects comprising three SixNy layers using a CMOS-compatible process. In these interconnects, the optical signals are coupled directly to a SixNy grating coupler in the middle SixNy layer and demultiplexed by a 1 × 4 SixNy array waveguide grating (AWG). The demultiplexed optical signals are interconnected from the middle SixNy layer to the bottom and top SixNy layers by four SiOxNy interlayer couplers. A low insertion loss and low crosstalk are achieved in the AWG. The coupling losses of the SiOxNy interlayer couplers and SixNy grating coupler are ∼1.52 dB and ∼4.2 dB, respectively.

13.
Plants (Basel) ; 10(10)2021 Oct 14.
Article in English | MEDLINE | ID: mdl-34685986

ABSTRACT

Small peptides and proteins play critical regulatory roles in plant development and environmental stress responses; however, only a few of these molecules have been identified and characterized to date because of their poor annotation and other experimental challenges. Here, we present that rice (Oryza sativa L.) OsS1Fa1, a small 76-amino acid protein, confers drought stress tolerance in Arabidopsis thaliana. OsS1Fa1 was highly expressed in leaf, culm, and root tissues of rice seedlings during vegetative growth and was significantly induced under drought stress. OsS1Fa1 overexpression in Arabidopsis induced the expression of selected drought-responsive genes and enhanced the survival rate of transgenic lines under drought. The proteasome inhibitor MG132 protected the OsS1Fa1 protein from degradation. Together, our data indicate that the small protein OsS1Fa1 is induced by drought and is post-translationally regulated, and the ectopic expression of OsS1Fa1 protects plants from drought stress.

14.
Methods Mol Biol ; 2328: 227-252, 2021.
Article in English | MEDLINE | ID: mdl-34251630

ABSTRACT

Tracking RNA transcription has been one of the most powerful tools to gain insight into the biological process. While a wide range of molecular methods such as northern blotting, RNA-seq, and quantitative RT-PCR are available, one of the barriers in transcript analysis is an inability to accommodate a sufficient number of samples to achieve high resolution in dynamic transcriptional changes. RASL-seq (RNA-mediated oligonucleotide Annealing, Selection, and Ligation with next-generation sequencing) is a sequencing-based transcription profiling tool that processes hundreds of samples assessing a set of over a hundred genes with a fraction of the cost of a conventional RNA-seq. We described a RASL-seq protocol for assessing 288 genes mostly including defense genes to capture their dynamic nature. We demonstrated that this transcriptional profiling method produced a highly reliable outcome comparable to a conventional RNA-seq and quantitative RT-PCR.


Subject(s)
Arabidopsis/metabolism , Gene Expression Profiling/methods , High-Throughput Nucleotide Sequencing/methods , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Host-Pathogen Interactions/genetics , Oligonucleotides/genetics , Plant Diseases/genetics , Real-Time Polymerase Chain Reaction
15.
Opt Express ; 29(8): 12001-12009, 2021 Apr 12.
Article in English | MEDLINE | ID: mdl-33984969

ABSTRACT

We present the flat-top supercontinuum source with high repetition rate over a broad bandwidth. The flatness and high repetition rate are achieved by iterative optical line-by-line spectrum shaping on electro-optic optical frequency combs. By applying Gaussian apodized pulse train to a highly nonlinear medium with optimized Gaussian coefficient and nonlinear polarization rotation techniques, we implemented here a flat-top supercontinuum with a 47.7 nm bandwidth at 3 dB and 30 GHz repetition rate. The generation of high repetition rate supercontinuum sources with smooth and coherent spectrum is the critical challenging task for many applications such as optical communications and the optical arbitrary waveform generation. This work leads us to new possibilities for generating hundreds or thousands of flattened coherent optical carriers with a simple configuration.

16.
Mol Plant Microbe Interact ; 34(9): 990-1000, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34010013

ABSTRACT

High-throughput resistance assays in plants have a limited selection of suitable pathogens. In this study, we developed a Pseudomonas syringae strain chromosomally tagged with the Nanoluc luciferase (NL) from the deep-sea shrimp Oplophorus gracilirostris, a bioluminescent marker significantly brighter than the conventional firefly luciferase. Our reporter strain tagged with NL was more than 100 times brighter than P. syringae tagged with the luxCDABE operon from Photorhabdus luminescens, one of the existing luciferase-based strains. In planta imaging was improved by using the surfactant Silwet L-77, particularly at a lower reporter concentration. Using this imaging system, more than 30 epigenetic mutants were analyzed for their resistance traits because the defense signaling pathway is known to be epigenetically regulated. SWC1, a defense-related chromatin remodeling complex, was found to be a positive defense regulator, which supported one of two earlier conflicting reports. Compromises in DNA methylation in the CG context led to enhanced resistance against virulent Pseudomonas syringae pv. tomato. Dicer-like and Argonaute proteins, important in the biogenesis and exerting the effector function of small RNAs, respectively, showed modest but distinct requirements for effector-triggered immunity and basal resistance to P. syringae pv. tomato. In addition, the transcriptional expression of an epigenetic component was found to be a significant predictor of its immunity contribution. In summary, this study showcased how a high-throughput resistance assay enabled by a pathogen strain with an improved luminescent reporter could provide insightful knowledge about complex defense signaling pathways.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Epigenesis, Genetic , Luciferases , Luminescence , Plant Diseases , Pseudomonas syringae/metabolism , Signal Transduction
17.
J Sch Psychol ; 83: 1-24, 2020 12.
Article in English | MEDLINE | ID: mdl-33276853

ABSTRACT

Motivation wields a tangible impact on students' academic functioning. Among the theoretical frameworks used to explain students' motivation to learn, Eccles et al.'s expectancy-value theory (1983) is one of the most influential. It has been used to investigate students' competence- and value-related beliefs and how they are associated with academic-related choices, learning behaviors, and achievement. In the learning context, cost has mostly been discussed under the expectancy-value framework as a sub-dimension of task value and conceptualized as reflecting the negative aspects of task engagement. The issue of cost has recently attracted growing interest among scholars, providing a way to explain the dynamics of student motivation. However, cost is still underexplored in the empirical literature. In the present study, we assessed adolescent students' perceived cost (i.e., effort cost, opportunity cost, ego cost, and emotional cost) of studying math and examined its unique relations with academic motivation and achievement. Across a series of three studies, we found that cost is empirically distinct from the utility, attainment, and interest components of task value and is closely related to students' maladaptive academic outcomes. In particular, cost showed unique associations with adolescent students' test anxiety, disorganization, adoption of avoidance goals, avoidance intentions, and academic achievement. The present study's findings highlight the importance of including cost as a unique construct alongside value to more fully capture students' motivational dynamics in school.


Subject(s)
Academic Success , Students/psychology , Adolescent , Educational Status , Female , Humans , Male , Mathematics , Motivation , Republic of Korea , Schools
18.
Sci Rep ; 10(1): 18636, 2020 10 29.
Article in English | MEDLINE | ID: mdl-33122804

ABSTRACT

This study was performed to investigate the Eustachian tube as a potential route for contralateral spreading following intratympanic nanoparticle (NP)-conjugated gentamicin injection in a rat model. Sprague-Dawley rats were divided into three groups and substances were injected in the right ear: group 1 (fluorescent magnetic nanoparticles [F-MNPs], n = 4), group 2 (F-MNP-conjugated gentamicin [F-MNP@GM], n = 2), and control group (no injections, n = 2). T2-weighted sequences corresponding to the regions of interest at 1, 2, and 3 h after intratympanic injection were evaluated, along with immunostaining fluorescence of both side cochlea. The heterogeneous signal intensity of F-MNPs and F-MNP@GM on T2-weighted images, observed in the ipsilateral tympanum, was also detected in the contralateral tympanum in 4 out of 6 rats, recapitulating fluorescent nanoparticles in the contralateral cochlear hair cells. Computational simulations demonstrate the contralateral spreading of particles by gravity force following intratympanic injection in a rat model. The diffusion rate of the contralateral spreading relies on the sizes and surface charges of particles. Collectively, the Eustachian tube could be a route for contralateral spreading following intratympanic injection. Caution should be taken when using the contralateral ear as a control study investigating inner-ear drug delivery through the transtympanic approach.


Subject(s)
Gentamicins/administration & dosage , Nanoparticles/chemistry , Animals , Injection, Intratympanic , Magnetic Resonance Imaging/methods , Rats , Rats, Sprague-Dawley
19.
Lab Chip ; 20(23): 4474-4485, 2020 11 24.
Article in English | MEDLINE | ID: mdl-33108430

ABSTRACT

The performance of micromixers, namely their mixing efficiency and throughput, is a critical component in increasing the overall efficiency of microfluidic systems (e.g., lab-on-a-chip and µ-TAS). Most previously reported high-performance micromixers use active elements with some external power to induce turbulence, or contain long and complex fluidic channels with obstacles to increase diffusion. In this paper, we introduce a new type of 3D impeller micromixer built within a single fused silica substrate. The proposed device is composed of microchannels with three inlets and a tank, with a mixing impeller passively rotated by axial flow. The passive micromixer is directly fabricated inside a glass plate using a selective laser-induced etching technique. The mixing tank, with its rotating shaft and 3D pitched blade impeller, exists within a micro-cavity with a volume of only 0.28 mm3. A mixing efficiency of 99% is achieved in mixing experiments involving three dye colours over flow rates ranging from 1.5-30 mL min-1, with the same flow rates also applied to a sodium hydroxide-based bromothymol blue indicator and a hydrochloric acid chemical solution. To verify the reliable performance of the proposed device, we compare the mixing index with a general self-circulation-type chamber mixer to demonstrate the improved mixing efficiency achieved by rotating the impeller. No cracking or breakage of the device is observed under high inner pressures or when the maximum flow rate is applied to the mixer. The proposed microfluidic system based on a compact built-in 3D micromixer with an impeller opens the door to robust, highly efficient, and high-throughput glass-based platforms for micro-centrifuges, cell sorters, micro-turbines, and micro-pumps.

20.
Front Psychol ; 10: 2146, 2019.
Article in English | MEDLINE | ID: mdl-31607985

ABSTRACT

The present study aims to investigate what factors determine students' engagement in mathematics. We examined the predictive relationships between interest, effort cost (i.e., the cost of making the effort), and three forms of academic engagement: persistence, cognitive engagement, and effort avoidance. In addition, we examined gender differences in these relationships. We recruited 546 8th and 9th graders for this study. Consistent with previous research, interest worked as a strong positive predictor of persistence and cognitive engagement, and it predicted effort avoidance negatively. Moreover, interest negatively predicted the perception of effort cost, which in turn positively predicted effort avoidance. Gender differences were found in the mean values of effort avoidance and in the prediction by interest of the perception of effort cost. Male students reported higher effort avoidance than female students, and the prediction by interest of the perception of effort cost was stronger among female students than among male students. These findings provide new insights into students' engagement in mathematics and the role of interest and effort cost in it.

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