Substrate-Controlled Divergent Synthesis of Benzimidazole-Fused Quinolines and Spirocyclic Benzimidazole-Fused Isoindoles.

A Rh(III)-catalyzed annulation of 2-arylbenzimidazoles with α-diazo carbonyl compounds via C-H activation/carbene insertion/intramolecular cyclization is explored. The switchable product selectivity is achieved by the use of distinct α-diazo carbonyl compounds. Benzimidazole-fused quinolines are obtained through [4 + 2] annulation exclusively when 2-diazocyclohexane-1,3-diones are used, where they act as a C2 synthon. Alternatively, diazonaphthalen-1(2H)-ones merely function as a one-carbon unit synthon to generate a quaternary center through [4 + 1] cyclization to afford spirocyclic benzimidazole-fused isoindole naphthalen-2-ones. A thorough mechanistic study reveals the course of the reaction.

[Research Progress on Solidification and MICP Remediation of Soils in Heavy Metal Contaminated Site].

Heavy metal pollution in soils of smelting sites is an important environmental problem to be solved urgently. Solidification technology has become one of the mainstream technologies for heavy metal remediation in contaminated sites owing to its shorter remediation time, low cost, and high treatment efficiency. On the basis of summarizing the latest research progress on the remediation of heavy metal pollution in sites by solidification in the past 10 years, this study focused on the mechanisms of solidification technology and analyzed the advantages and disadvantages of different mechanisms (mechanism of inorganic materials, mechanism of organic materials, mechanism of mechanical ball milling, and mechanism of microbial-induced carbonate mineralization (MICP)) and their scope of application. Then, according to the research focus and development trend presented by CiteSpace, the application prospects and limiting factors of MICP technology for the solidification and remediation of heavy metal pollution in sites were summarized from three aspects:the application of MICP in multi-metal remediation, the application of MICP composites in contaminated sites, and the influencing factors of MICP technology application. Finally, the prospects and challenges in solidification technology were put forward in order to provide reference for the future development.

Small-Molecule Analysis Based on DNA Strand Displacement Using a Bacteriorhodopsin Photoelectric Transducer: Taking ATP as an Example.

A uniformly oriented purple membrane (PM) monolayer containing photoactive bacteriorhodopsin has recently been applied as a sensitive photoelectric transducer to assay color proteins and microbes quantitatively. This study extends its application to detecting small molecules, using adenosine triphosphate (ATP) as an example. A reverse detection method is used, which employs AuNPs labeling and specific DNA strand displacement. A PM monolayer-coated electrode is first covalently conjugated with an ATP-specific nucleic acid aptamer and then hybridized with another gold nanoparticle-labeled nucleic acid strand with a sequence that is partially complementary to the ATP aptamer, in order to significantly minimize the photocurrent that is generated by the PM. The resulting ATP-sensing chip restores its photocurrent production in the presence of ATP, and the photocurrent recovers more effectively as the ATP concentration increases. Direct and single-step ATP detection is achieved in 15 min, with detection limits of 5 nM and a dynamic range of 5 nM-0.1 mM. The sensing chip exhibits high selectivity against other ATP analogs and is satisfactorily stable in storage. The ATP-sensing chip is used to assay bacterial populations and achieves a detection limit for Bacillus subtilis and Escherichia coli of 102 and 103 CFU/mL, respectively. The demonstration shows that a variety of small molecules can be simultaneously quantified using PM-based biosensors.

Research on IMU-Assisted UWB-Based Positioning Algorithm in Underground Coal Mines.

The application of an ultra-wideband (UWB) positioning system in a Global Positioning System (GPS) denial environment such as an underground coal mine, mainly focuses on position information and rarely involves information such as direction attitude. Position accuracy is often affected by multipath, non-visible ranges, base station layout, and more. We proposed an IMU-assisted UWB-based positioning system for the provision of positioning and orientation services to coal miners in underground mines. The Error-State Kalman Filter (ESKF) is used to filter the errors in the measured data from the IMU-assisted UWB positioning system to obtain the best estimate of the error for the current situation and correct for inaccuracies due to approximations. The base station layout of the IMU-assisted UWB positioning system was also simulated. The reasonable setting of the reference base station location can suppress multi-access interference and improve positioning accuracy to a certain extent. Numerous simulation experiments have been conducted in GPS denial environments, such as underground coal mines. The experimental results show the effectiveness of the method for determining the position, direction, and attitude of the coal miner under the mine, which provides a better reference value for positioning and orientation in a GPS rejection environment such as under the mine.

The effect of extracellular polymeric substances (EPS) of iron-oxidizing bacteria (Ochrobactrum EEELCW01) on mineral transformation and arsenic (As) fate.

Extracellular polymeric substances (EPS) are an important medium for communication and material exchange between iron-oxidizing bacteria and the external environment and could induce the iron (oxyhydr) oxides production which reduced arsenic (As) availability. The main component of EPS secreted by iron-oxidizing bacteria (Ochrobactrum EEELCW01) was composed of polysaccharides (150.76-165.33 mg/g DW) followed by considerably smaller amounts of proteins (12.98-16.12 mg/g DW). Low concentrations of As (100 or 500 µmol/L) promoted the amount of EPS secretion. FTIR results showed that EPS was composed of polysaccharides, proteins, and a miniscule amount of nucleic acids. The functional groups including -COOH, -OH, -NH, -C=O, and -C-O played an important role in the adsorption of As. XPS results showed that As was bound to EPS in the form of As3+. With increasing As concentration, the proportion of As3+ adsorbed on EPS increased. Ferrihydrite with a weak crystalline state was only produced in the system at 6 hr during the mineralization process of Ochrobactrum sp. At day 8, the minerals were composed of goethite, galena, and siderite. With the increasing mineralization time, the main mineral phases were transformed from weakly crystalline hydrous iron ore into higher crystallinity siderite (FeCO3) or goethite (α-FeOOH), and the specific surface area and active sites of minerals were reduced. It can be seen from the distribution of As elements that As is preferentially adsorbed on the edges of iron minerals. This study is potential to understand the biomineralization mechanism of iron-oxidizing bacteria and As remediation in the environment.

WS2 Transistors with Sulfur Atoms Being Replaced at the Interface: First-Principles Quantum-Transport Study.

Reducing the contact resistance is one of the major challenges in developing transistors based on two-dimensional materials. In this study, we perform first-principles quantum-transport calculations by adopting a novel type of partially sulfur-replaced edge contact metal/WSX/WS2 in order to lower the Schottky barrier height and in turn reduce the contact resistance. Here, the sulfur replacements produce a segment of the metamaterial WSX (X = P, As, F, and Cl), using group V or halogen atoms to substitute sulfur atoms on one side of a WS2 monolayer. We further compare the effects of such sulfur replacements on the interface metallization and bonding. Such WSX-buffered contacts exhibit contact resistances as low as 142 and 173 Ω·µm for the p-type Pt/WSP/WS2 and n-type Ti/WSCl/WS2 edge contacts, respectively. Moreover, ab initio molecular dynamics is employed to observe a stable standalone WSX monolayer at room temperature.

A Stable PDLC Film with High Ageing Resistance from an Optimized System Containing Rigid Monomer.

With the switchability between transparent and light-scattering states, polymer-dispersed liquid crystals (PDLC) are widely used as smart windows, flexible display devices, projectors, and other devices. In outdoor applications, in addition to excellent electro-optical properties, there is also a high demand for film stability. In this work, a PDLC film with high mechanical strength and structural stability is prepared that can maintain stability at 80 °C for 2000 h. By choosing liquid crystals with a wide temperature range, adopting acrylate polymer monomers containing hydroxyl groups, and adjusting the polymer content, the PDLC film can work well from -20 °C to 80 °C. On this basis, the effects of the introduction of rigid monomers on the mechanical properties and electro-optical properties of PDLC films are investigated.

Rh(III)-Catalyzed (4 + 1) Annulation of Pyrazol-3-ones with Alkynoates via Ortho-Alkenylation/Cyclization Cascade: Synthesis of Indazole-Fused Pyrazoles.

A facile synthesis of novel indazole-fused pyrazoles from pyrazol-3-ones and alkynoate esters/amides via Rh(III)-catalyzed sequential C-H activation/ortho-alkenylation/intramolecular cyclization cascade is reported. The important characteristic of this method is that the resulting scaffold bearing quaternary carbon has been obtained through unusual [4 + 1] rather than expected [4 + 2] addition where alkynoate acts as a one-carbon unit.

Do Flipped Learning and Adaptive Instruction Improve Student Learning Outcome? A Case Study of a Computer Programming Course in Taiwan.

Flipped learning could improve the learning effectiveness of students. However, some studies have pointed out the limitations related to flipped classrooms because the content of the flipped course does not vary according to the needs of the students. On the other hand, adaptive teaching, which customizes the learning mode according to the individual needs of students, can make up for some of the shortcomings of flipped teaching. This study combines adaptive teaching with flipped teaching and applies it to face-to-face classroom activities. The purpose of this research is to explore whether the implementation of flipping and adaptive learning in a computer programming course can improve the learning effectiveness of students. The experimental subjects of this study are the sophomore students in the Department of Information Management. The flipped classroom with adaptive instruction has been realized in the limited course time. This study uses questionnaires to collect pre- and post-test data on the "learning motivation" of students. The learning effectiveness was evaluated based on the students' previous programming course (C language) and the semester scores of this course. Research results show that the post-test "learning motivation" has improved overall compared with the pre-test, and the learning effect is significant. The results of this research not only prove the effectiveness of modern teaching theories in programming courses but also lay the foundation for future teaching design.

Toward COVID-19 Information: Infodemic or Fear of Missing Out?

Coronavirus disease 2019 (COVID-19) has caused a global pandemic and exerted a profound physiological and mental impact on the public. Due to anxiety from being bombarded by information from the news and social media, people may constantly read and repost, with a fear of missing out (FOMO), information about COVID-19 on social media. So far, there has been little research on COVID-19 FOMO. We therefore compiled the COVID-19 information fear of missing out scale (CIFS) and administered it to 1178 adults in Taiwan to identify the possible factors influencing CIFS scores. We demonstrated that the CIFS had good reliability, factor validity, and criterion validity. With regard to demographic variables, we found that gender, marital status, travel time to the nearest hospital, and educational background influenced CIFS scores. In contrast, the participant age and whether he or she lived in an urban area did not affect the CIFS scores. With regard to social media usage, social media usage time (r = 0.025) and the numbers of COVID-19-related posts read on social media (r = 0.117) or instant messaging (r = 0.169) were not highly correlated with CIFS scores. Rather, CIFS scores were found to be significantly correlated to the frequency of reposting COVID-19-related information on social media (r = 0.497) and on instant messaging (r = 0.447). These results indicate that CIFS scores are closely associated not with passive browsing on social media but with the frequency at which an individual actively reposts information. In other words, what creates CIF is not an overabundance of information (i.e., an infodemic) but the active reposting and interpretation of information. Individual autonomy for interpretation of the received information and self-determination about reposting are key factors for COVID-19 information FOMO. When facing the COVID-19-related news on social media, it is the active information-related FOMO, not the passive infodemic, that influences our social media usage.

Ephemeral but Influential? The Correlation between Facebook Stories Usage, Addiction, Narcissism, and Positive Affect.

Despite the steep increase in Facebook Stories users, there is scant research on this topic. This study compared the associations of frequency of Stories update, frequency of news feed updates, time spent reading Stories, and time spent reading news feeds, with regard to social media addiction, narcissism, and positive affect in college students. We recruited a sample of 316 college students from Taiwan. The analytical results show that Facebook Stories are more addictive and provoke more positive affect than conventional news feeds. Moreover, only usage behaviors associated with Stories predict narcissism. This study also found that the prediction of news feeds with regard to addiction, narcissism, and positive affect also seems to be diminishing and is being replaced by those of Stories. Future studies on the psychological consequences and predictors of social media usage should regard Stories as a crucial variable.

Social Facebook With Big Six Approaches for Improved Students' Learning Performance and Behavior: A Case Study of a Project Innovation and Implementation Course.

In Taiwan, classroom lectures are gradually shifting from traditional to diverse digital learning environments through social network websites. Facebook is being used to provide a space for sharing and discussing learning materials and knowledge for teachers and students. In this paper, we focus on the effects of applying Big Six approaches to Facebook on students' learning performance and behavior in a project innovation and implementation course. The participants were 72 first-year students in a college located in north Taiwan. The experimental participants who took the course were divided into two classes: the experimental group and the control group. While the experimental group used Facebook combined with Big Six approaches, the control group used traditional classroom tools combined with Big Six approaches. The experimental results show that the learning performance and creativity development of students from the experimental group are enhanced after using Facebook with Big Six approaches indicating a great social interaction and discussion cycle. On the other hand, students from the control group were only guided by the teacher. Owing to the lack of interactions between the Internet and the social learning community, there is no obvious enhancement in students' learning performance and creativity. In addition, we found that the teacher practiced the tips for guiding experimental students to solve the encountered problem, and then the students replied to the classmate's questions.

Versatile Protein-A Coated Photoelectric Immunosensors with a Purple-Membrane Monolayer Transducer Fabricated by Affinity-Immobilization on a Graphene-Oxide Complexed Linker and by Shear Flow.

Bacteriorhodopsin-embedded purple membranes (PM) have been demonstrated to be a sensitive photoelectric transducer for microbial detection. To efficiently prepare versatile BR-based immunosensors with protein A as antibody captures, a large, high-coverage, and uniformly oriented PM monolayer was fabricated on an electrode as an effective foundation for protein A conjugation through bis-NHS esters, by first affinity-coating biotinylated PM on an aminated surface using a complex of oxidized avidin and graphene oxide as the planar linker and then washing the coating with a shear flow. Three different polyclonal antibodies, each against Escherichia coli, Lactobacillus acidophilus, and Streptococcus mutans, respectively, were individually, effectively and readily adsorbed on the protein A coated electrodes, leading to selective and sensitive quantitative detection of their respective target cells in a single step without any labeling. A single-cell detection limit was achieved for the former two cells. AFM, photocurrent, and Raman analyses all displayed each fabricated layer as well as the captured bacteria, with AFM particularly revealing the formation of a massive continuous PM monolayer on aminated mica. The facile cell-membrane monolayer fabrication and membrane surface conjugation techniques disclosed in this study may be widely applied to the preparation of different biomembrane-based biosensors.

Fluorocarbon and hydrocarbon N-heterocyclic (C5-C7) imidazole-based liquid crystals.

By using three synthetic protocols, a series of fluorocarbon and hydrocarbon N-heterocyclic imidazole-based liquid crystals (LCs) and related imidazolium-based ionic liquid crystals (ILCs) have been prepared. The ring size of the N-heterocycle and the length of the N-terminal chain (on the imidazolium unit in the ILCs) were modified, and the influence of these structural parameters on liquid-crystal phases was investigated by means of polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). These new ILCs exhibit a disordered smectic phase (SmA), good thermal stabilities, a broad smectic phase range, a high dipole moment, relatively low melting points, but high clearing points and strong emission fluorescence relative to imidazole-based LCs. These encouraging results have led us to believe these fluorocarbon and hydrocarbon N-heterocyclic imidazole-based LCs and related imidazolium-based ILCs could be used as new liquid-crystalline materials.

An integrated thermal compensation system for MEMS inertial sensors.

An active thermal compensation system for a low temperature-bias-drift (TBD) MEMS-based gyroscope is proposed in this study. First, a micro-gyroscope is fabricated by a high-aspect-ratio silicon-on-glass (SOG) process and vacuum packaged by glass frit bonding. Moreover, a drive/readout ASIC, implemented by the 0.25 µm 1P5M standard CMOS process, is designed and integrated with the gyroscope by directly wire bonding. Then, since the temperature effect is one of the critical issues in the high performance gyroscope applications, the temperature-dependent characteristics of the micro-gyroscope are discussed. Furthermore, to compensate the TBD of the micro-gyroscope, a thermal compensation system is proposed and integrated in the aforementioned ASIC to actively tune the parameters in the digital trimming mechanism, which is designed in the readout ASIC. Finally, some experimental results demonstrate that the TBD of the micro-gyroscope can be compensated effectively by the proposed compensation system.

Factors that influence acceptance of web-based e-learning systems for the in-service education of junior high school teachers in Taiwan.

Web-based e-learning is not restricted by time or place and can provide teachers with a learning environment that is flexible and convenient, enabling them to efficiently learn, quickly develop their professional expertise, and advance professionally. Many research reports on web-based e-learning have neglected the role of the teacher's perspective in the acceptance of using web-based e-learning systems for in-service education. We distributed questionnaires to 402 junior high school teachers in central Taiwan. This study used the Technology Acceptance Model (TAM) as our theoretical foundation and employed the Structure Equation Model (SEM) to examine factors that influenced intentions to use in-service training conducted through web-based e-learning. The results showed that motivation to use and Internet self-efficacy were significantly positively associated with behavioral intentions regarding the use of web-based e-learning for in-service training through the factors of perceived usefulness and perceived ease of use. The factor of computer anxiety had a significantly negative effect on behavioral intentions toward web-based e-learning in-service training through the factor of perceived ease of use. Perceived usefulness and motivation to use were the primary reasons for the acceptance by junior high school teachers of web-based e-learning systems for in-service training.

Poly[[tetra-aqua-µ(4)-fumarato-di-µ(3)-fumarato-dineodymium(III)] trihydrate].

The title coordination polymer, {[Nd(2)(C(4)H(2)O(4))(3)(H(2)O)(4)]·3H(2)O}, was synthesized by the reaction of neodymium(III) nitrate hexa-hydrate with fumaric acid in a water-methanol (7:3) solution. The asymmetric unit comprises two Nd(3+) cations, three fumarate dianions (L(2-)), four aqua ligands and three uncoordinated water mol-ecules. The carboxyl-ate groups of the fumarate dianions exhibit different coordination modes. In one fumarate dianion, two carboxyl-ate groups chelate two Nd(3+) cations, while one of the O atoms is coordinated to another Nd(3+) cation. Another fumarate dianion bridges three Nd(3+) cations: one of the carboxyl-ate groups chelates one Nd(3+) cation, while the other carboxyl-ate group bridges two Nd(3+) cations in a monodentate mode. The third fumarate dianion bridges four Nd(3+) cations, where one of the carboxyl-ate groups chelates one Nd(3+) cation and coordinates in a monodentate mode to a second Nd(3+), while the second carboxyl-ate groups bridges two Nd(3+) cations in a monodentate mode and one O atom is coordinated to one Nd(3+) cation. The Nd(3+) cations are in a distorted tricapped-trigonal prismatic environment and coordinated by seven O atoms from the fumarate ligands and two O atoms from water mol-ecules. The Nd(3+) cations are linked by two carboxyl-ate O atoms and two carboxyl-ate groups, generating infinite Nd-O chains to form a three-dimensional framework. There are O-H⋯O and C-H⋯O hydrogen-bonding interactions between the coordin-ated and uncoordinated water mol-ecules and carboxyl-ate O atoms.