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Green and sustainable power sources for next-generation electronics are being developed. A cellulose paper-based triboelectric nanogenerator (TENG) was fabricated to harness mechanical energy and convert it into electricity. This work proposes a novel approach to modify cellulose paper with natural dyes, including chlorophyll from spinach, anthocyanin from red cabbage, and curcumin from turmeric, to enhance the power output of a TENG. All the natural dyes are found to effectively improve the energy conversion performance of a cellulose paper-based TENG due to their photogenerated charges. The highest power density of 3.3 W/m2 is achieved from the cellulose paper-based TENG modified with chlorophyll, which is higher than those modified with anthocyanin and curcumin, respectively. The superior performance is attributed not only to the photosensitizer properties but also the molecular structure of the dye that promotes the electron-donating properties of cellulose. [ABSTRACT FROM AUTHOR]

The surface of plant fibers was modified by silane coupling agents to prepare plant fiber/polylactic acid (PLA) composites, which can improve the dispersion, adhesion, and compatibility between the plant fibers and the PLA matrix. In this work, three silane coupling agents (KH550, KH560, and KH570) with different molecular structures were used to modify the surface of waste corrugated paper fibers (WFs), and dichloromethane was used as the solvent to prepare the WF/PLA composites. The effects of different silane coupling agents on the microstructure, mechanical properties, thermal decomposition, and crystallization properties of the composites were studied. The mechanical properties of the composites treated with 4 wt% KH560 were the best. Silane coupling agents can slightly improve the melting temperature of the composites, and WFs can promote the crystallization of PLA. The modification of WFs by silane coupling agents can increase the decomposition temperature of the WF/PLA composites. The content and type of silane coupling agent directly affected the mechanical properties of the WF/PLA composites. The interfacial compatibility between the WFs and PLA can be improved by using a silane coupling agent, which can further enhance the mechanical properties of WF/PLA composites. This provides a research basis for the further improvement of the performance of plant fiber/PLA composites. [ABSTRACT FROM AUTHOR]

Paper-based microfluidic devices (µPAD) are a burgeoning platform of microfluidic analysis technology. The method described herein is for use in undergraduate and high school chemistry laboratories. A simple and convenient µPAD was fabricated by easy patterning of filter paper using a permanent marker pen. The usefulness of the device was demonstrated by determination of nitrite ion concentration employing a colorimetric assay. The results for real sample detection using this µPAD were satisfactory and show promise for use in other applications.

In this project, we explore the use of threshold concept theory as a design basis for development of Interactive Virtual Laboratories in thermodynamics. Thermodynamics is a difficult subject for chemical and biological engineering students to master. One reason for the difficulty is the diverse and challenging set of threshold concepts that they must coherently synthesize and be able to apply in a diverse range of contexts. Based on our experience and from reports in the literature, we have identified a set of threshold concepts we propose are critical for mastery of thermodynamics. To help students better learn these concepts, we have been developing Interactive Virtual Laboratories. This paper describes the development and initial investigation of two such laboratories. They are available for instructors to use through the AIChE Concept Warehouse website (http://cw.edudiv.org/). The Interactive Virtual Laboratories are a series of two-dimensional simulations designed to address the targeted threshold concepts. The design of these laboratories is based on allowing students to see and explore alternative representations of the phenomena that they are learning. They allow inquirybased, scaffolded activity, and each has several activities that provide multiple representations. These activities guide students to perform virtual experiments, and also to place the virtual experiments in the context of the concepts that they are learning. They explain concepts in a way that is less abstract and more intuitive to students by providing a dynamic representation of phenomena at a molecular level. Students are expected to answer numerical questions and, whenever possible, predict and explain the effects of macroscopic changes (i.e., pressure, temperature, composition, energy) based on observations of molecular properties. In the study reported in this paper, we investigate how students experience the laboratories and whether the students perceive the simulations are beneficial towards learning. The two interactive virtual laboratories studied address the concepts of Pv work and reversible processes. Eight participants took part in the clinical study outside of the engineering classroom. All students had previously taken a thermodynamics course and had access to a thermodynamics textbook and the internet as they completed the laboratory. A "think aloud" protocol was used where students were audio recorded as they verbally described their actions in completing the laboratory. The transcribed audio recordings together with video recordings of the computer screen on which they worked were analyzed. After completing the laboratory, a semi-structured interview asked participants about their perceptions of the simulation's effectiveness, their previous thermodynamics experience, and a brief assessment of what they learned. All interviews were transcribed for analysis. The participants generally responded positively to the simulations. Seven out of eight students explicitly stated that the dynamic simulations helped them visualize and engage with the processes more than they could with the static depictions in books or lecture. However, some difficulties were observed, including interacting with the interface and understanding specifically what a question was asking. One participant found the interactivity to be unintuitive. We also noticed a relation between how the participants framed knowledge and their approach to completing the laboratory. Students who activated more sophisticated frames typically completed the simulation more quickly and accurately than those with more naive frames. Students who did not do as well tended to focus on trying to identify equations they had used in the past, even going so far as to use them in an unsuitable context. On the other hand, students who completed the simulations accurately and more quickly appeared to integrate what they were seeing on the screen with their foundational conceptual knowledge to form new understanding.

We describe a laboratory experiment that employs the Nanoceria Reducing Antioxidant Capacity (or NanoCerac) Assay to introduce students to portable nanoparticle-based paper sensors for rapid analysis and field detection of polyphenol antioxidants. The experiment gives students a hands-on opportunity to utilize nanoparticle chemistry to develop their own devices to test antioxidant-containing solutions, such as tea and other beverages, for polyphenolic content, a characteristic likely correlated with health benefits. The method utilizes sensing nanoparticles of cerium oxide that respond visually to antioxidant compounds. Due to ease of use of these sensors, inexpensive materials, and short time requirement (~1 h), this lab is appropriate for primary, secondary, and undergraduate courses. The lab and lesson expose students to the fields of nanotechnology, analytical chemistry, antioxidant chemistry, and antioxidant characteristics of botanicals and food constituents.

A variety of fruits and vegetables, including raspberries, blueberries, Concord grapes, blackberries, strawberries, peaches, eggplant, red cabbage, and red onions, contain flavonoid compounds known as anthocyanins that are responsible for the blue-red color and the astringent taste associated with such foods. In addition, anthocyanins exhibit a wide range of chemical properties, such as radical scavenging, metal chelation, pH-dependent color changes, and intramolecular stabilization. Two experiments have been developed for anthocyanin-containing extracts isolated from freeze-dried berries to teach students the skills of solid-liquid extraction, paper chromatography, UV-vis spectroscopic characterization, and detection and evaluation of radical scavenging properties.

A simple and effective hands-on classroom activity designed to illustrate basic polymer concepts is presented. In this activity, students build primary structures of homopolymers and different arrangements of monomers in copolymer using paper clips as monomers. The activity supports formation of a basic understanding of polymer structures, tacticity, copolymers, degree of polymerization, arrangement of monomers in copolymers, and polymer chain entanglement.

Instructions are given for constructing two models, one to illustrate the general principles of symmetry in T=1, T=3, and T=4 viruses, and the other to illustrate the disposition of protein subunits in the T=3 plant viruses and the picornaviruses. (Author/CW)

• A cellulose membrane serves as stationary phase for fractionation of human saliva. • Interaction between red wine and saliva was revealed by a dichromatic analysis. • A non-diffusible salivary fraction showed the highest affinity for wine components. • Diffusion of a diffusible salivary fraction declines due to interaction with wine. • A point of equivalence occurs when a wine/saliva mix shows no diffusible fraction. In-mouth interaction of red wine compounds with salivary proteins is a primary event allegedly responsible for eliciting the mouth-feel sensation of astringency. Those interactions have been currently associated with precipitation of salivary protein/polyphenol complexes. However, such single physicochemical evidence for interaction does not account for the complexity of astringency. This study aimed to develop a paper chromatography method to assess interactions between red wine and the salivary protein fraction using stepwise series of red wine/saliva binary mixtures from 100% wine to 100% saliva ("Alpha and Omega series"). Aliquots of each one of the mixtures were spotted on a cellulose membrane to scrutinize independently the distribution areas of wine components (naturally pink-colored) and salivary protein (stained blue in Coomassie Brilliant R-250). This double target detection revealed interactions between saliva and red wine components along most of the quantitative Alpha and Omega series, a point of equivalence corresponding to maximum interactivity for both complex reactants and a non-diffusible sub-fraction of saliva displaying the highest interactivity. The results indicate a novel way to assess quantitatively physicochemical interactions between red wines and human saliva but also provide new lights to approach the identification of molecular salivary structures involved in triggering astringency. [ABSTRACT FROM AUTHOR]

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Students perceive molecular bonding as an abstract concept; therefore, learning this concept seems uninteresting and difficult. A strategically designed learning object (LO), such as in the form of a simulation, can be used to help students acquire accurate mental images and build appropriate schema in addition to providing a concrete learning experience and encouraging knowledge construction. This paper presents an evaluation of the design and development of the "Making Molecules" simulation through students' perceptions of the previous version and recommendations for improving a future version. Data were collected from two online chemistry courses (N = 159) through an anonymous online survey. Results suggest that students responded positively to the use of the simulation. They reported gaining a better understanding of molecular bonding through an interactive learning experience. One of their recommendations was to include more learning tasks related to complex molecules, expressing an interest in learning more about chemistry. This paper provides insights for educators and instructional designers regarding selection and/or design of an LO for optimizing student learning of complex topics.

Describes the chemical structure of paper, including subatomic particles, atoms and molecules, and the forces that bond atoms into molecules, molecules into chains, chains into sheets, and sheets into layers. Acid is defined, and the deleterious role of acid in breaking the forces that bond atoms into molecules is detailed. (EJS)

Although arynes are usually considered fleeting intermediates, they are highly valuable synthons because they enable the introduction of aromatic rings and the simultaneous formation of new bonds at two sites. Although catalytic reactions using transition metals are excellent method for constructing complex polycyclic aromatic molecules in a single step, the use of asymmetric catalysis for the capture of arynes remains a crucial goal for the progress of aryne chemistry. Catalytic asymmetric reactions of arenes are challenging, requiring sufficient interactions between the neutral and highly reactive short-lived aryne intermediates in a stereo-controlled fashion. In addition, spontaneous decomposition, as well as side reactions, has hindered their development and, until recently, highly enantioselective reactions using arynes had remained elusive. This Review highlights asymmetric reactions using arynes, featuring diastereoselective, enantioselective and catalytic enantioselective reactions., (© 2023. Springer Nature Limited.)

This article focuses on the nature of acidity in pulp paper as found in comic books and library collections. Some of the various factors that contribute to the deterioration of paper are considered from a chemical perspective. (CW)

The development of OLED materials by molecular design is important for high performance organic light emitting diode because tailoring the molecular structures can dramatically tune the properties such as efficiency, color, stability of device. Near‐infrared organic light‐emitting diodes (NIR OLEDs) with heavy metals or TADF materials are regularly reported due to the advantages of their various applications in healthcare services, veil authentication, and night vision displays. In this paper, we are summarized the collection of innovative organic near‐infrared (NIR) emitters which is crucial factor to design specific NIR emitter for NIR OLEDs [ABSTRACT FROM AUTHOR]

We investigated the performance of attenuated total reflectance--Fourier-transform infrared (ATR-FTIR) spectroscopy to rapidly identify intentional additives in a variety of items commonly handled by consumers and workers. We investigated ortho-phthalate esters, specific alternative plasticizers, and flame retardants in food contact materials and consumer products. We also investigated bisphenol A (BPA) and bisphenol S (BPS) developers in thermal paper purchase receipts. Applications include regulatory compliance screening and product deformulation. We compared FTIR results with mass spectrometry measurements. Samples were analyzed either intact or after a simple liquid-phase extraction using small amounts of nonhalogenated solvents. These methods greatly reduced the time and expense of identifying intentionally added phthalates and other plasticizers compared with more sensitive methods. Similarly, BPA and BPS were readily identified in receipts and organophosphorus flame retardants were identified in child car seats. In some samples, FTIR detected novel or unexpected additives not detected by conventional targeted methods. These approaches are useful for screening diverse product samples for intentional additives with a relatively portable instrument while generating very low volumes of spent solvent. [ABSTRACT FROM AUTHOR]

Spatial ability is an important tool in chemistry and this ability can be improved. Various technologies have been used to improve spatial ability. However, it is not clear if viewing technologies should take the place of the model kit; the traditional method of learning about molecular structures. Our research aims to address this gap. In our study, we aimed to take advantage of student affinity to technology to drive spatial ability improvements (in the context of chemistry) by having students experience molecules in virtual space using modern viewing technologies (WBVE, AR, and VR). Students were first engaged with the technologies then were assessed to see if their ability to solve problems relating to 3D-molecular structure improved. The mean spatial ability of students improved over the course of the semester (permutation test, p < 0.05) and students using model kits scored higher than those using the technologies (t-test, p < 0.05). The collection and assessment of anonymous, aggregated, student responses for this study was conducted with the approval of the University of Calgary ethics board (REB13-0724). [Articles in this journal were presented at the University of Calgary Conference on Postsecondary Learning and Teaching.]

Develops the concept of oscillatory v dissipative limits as it applies to electronic excited state processes in molecular systems. Main emphasis is placed on the radiative and nonradiative dynamics of the excited state of a molecule prepared by interaction with light or some other excitation source. (BT)

A system for construction of simple poster-board models is described. The models dynamically demonstrate the symmetry operations of proper rotation, improper rotation, reflection, and inversion for the chemically important point groups D[subscript 3h], D[subscript 4h], D[subscript 5h], D[subscript 6h], T[subscript d], and O[subscript h]. The models also clearly show where the applicable point, line, or plane lies in relation to the other symmetry elements. This method is presented for use as a one-period exercise in the laboratory course that traditionally accompanies the third- or fourth-year undergraduate-level (advanced) inorganic chemistry lecture course. (Contains 1 figure.)

Abstract: Papers have a complex hierarchical structure and the end-user functionalities such as hydrophobicity are controlled by a finishing layer. The application of an organic nanoparticle coating and drying of the aqueous dispersion results in an unique surface morphology with microscale domains that are internally patterned with nanoparticles. Better understanding of the multi-scale surface roughness patterns is obtained by monitoring the topography with non-contact profilometry (NCP) and atomic force microscopy (AFM) at different sampling areas ranging from 2000μm×2000μm to 0.5μm×0.5μm. The statistical roughness parameters are uniquely related to each other over the different measuring techniques and sampling sizes, as they are purely statistically determined. However, they cannot be directly extrapolated over the different sampling areas as they represent transitions at the nano-, micro-to-nano and microscale level. Therefore, the spatial roughness parameters including the correlation length and the specific frequency bandwidth should be taken into account for each measurement, which both allow for direct correlation of roughness data at different sampling sizes. [Copyright &y& Elsevier]

For proper treatment, recycling, or disposal of the pulp and paper mill secondary sludge qualitative and quantitative determination of its characteristics are necessary. Chemical extraction, quantitative characterization, and spectroscopic experiments have been performed to determine the molecular composition and chemical functionality of a pulp and paper mill secondary sludge. In order to extract the low-molecular-weight substances, soxhlet extraction with polar and non-polar solvents was performed where most of the target substances (17 1.3%.) were extracted after 2 hours. Over time, this extraction followed a first-order kinetics. Fiber analyses have shown 12 3% lignin, 28 3% cellulose, and 12 4% hemicelluloses content. The ash content was about 17 0.5%. In this work, 7 and 16% intra- and extracellular polymeric substances, respectively, were extracted from the secondary sludge. EPS and mixture of intra- and extracellular biopolymers have shown similar chemical functionalities. These analyses confirmed that the paper secondary sludge consisted mainly of wood fiber, i.e. lignocellulosic substances, along with proteins and polysaccharides originated from microorganisms. [ABSTRACT FROM AUTHOR]

Abstract: Kaolinite was successfully intercalated by urea in a static and sealed condition at 95°C for 3.5h. The urea-intercalated kaolinite was applied for paper coating. The high shear rate rheologies were used to study the flowing properties of them and to stimulate the realistic coating paper at ultra high shear rate. The structure, morphology, chemical constitution, particle size distribution and rheological properties of the samples were measured by XRD, SEM, ICP-MS, particle size analyzer and by rheometer, respectively. The particle size of urea-intercalated kaolinite became finer with the growth of intercalation ratio. The rheological properties of slurries were changed from pseudo plastic behavior to complex flow and the solid content of slurries at the viscosity of 500mPa·s increased from 70.84 % to 74.09 % due to intercalation of urea. The urea-intercalated kaolinite improved slightly the properties of papers, while the better rheology could enhance the process of coating paper with ultra high speed. [Copyright &y& Elsevier]

• It is shown that the commented paper has severe errors. • The analysis of the diffraction pattern was made without success. • The chemical composition of the studied crystals is unknown. My comments concern the errors in the crystallographic part of the commented paper. Moreover, the true chemical composition of the studied sample is different than BaNaFeWO 6 as proposed by authors. Therefore, the subsequent data on other measurements may have no scientific value. [ABSTRACT FROM AUTHOR]

In this paper, we describe a dynamic-model as a strategy to teach DNA transcription and translation in an active way. This activity aims to provide learning beyond memorisation through the simulation of molecular processes, stimulating the elaboration of questions and hypotheses by students. The dynamic consists of four steps, starting with different problem situations which provide a context and encouragement to start the activity. The next steps connect these problems with DNA transcription and translation, requiring the active participation of students to simulate these processes through a construction of a model based on an iron board and representations of cellular structures, enzymes and genetic sequences fixed in magnets. An implementation experience of this dynamic, applied to 21 undergraduate veterinary students at a public university in the city of Curitiba, Paraná State, Brazil, is also described. Data from pre and post-questionnaires suggest knowledge about DNA transcription and translation was improved and some previous mistakes were clarified. Among the positive aspects that were cited by the students, the words visualisation and playful were more frequent, which reflect the didactic aspects of the dynamic. Some points of attention are discussed throughout the paper, as well as educational implications associated with the material and its potential to promote active learning.

This paper addresses policy effects of international mobility in developing countries. It proposes a multilevel approach to study research training policies, specifically focusing on international mobility schemes as capacity-building instruments, where effects need to be identified at both individual and organizational levels. The paper asserts that current categorizations of country efforts to build a solid scientific base should consider transference of effects in domestic research contexts. Using a survey and interview-based study of a mobility policy in Mexico, and nanotechnology-related disciplines and sectors, this paper's findings suggest that mobility policies are crucial in creating high-quality individual research skills, but that their impact on building domestic research capacity may be modest. This paper contributes to the evaluation literature on national research training programs and their influence on research capacity in two ways. First, it mobilizes a multilevel analytical approach to examine the effects of policies on individuals and organizations, offering a broader conceptualization of impact. Second, by introducing these individual and organizational effects, the paper provides insights into how effects are enacted and transferred.

We conducted a controlled investigation to examine whether a combination of computer imagery and tactile tools helps introductory cell biology laboratory undergraduate students better learn about protein structure/function relationships as compared with computer imagery alone. In all five laboratory sections, students used the molecular imaging program, Protein Explorer (PE). In the three experimental sections, three-dimensional physical models were made available to the students, in addition to PE. Student learning was assessed via oral and written research summaries and videotaped interviews. Differences between the experimental and control group students were not found in our typical course assessments such as research papers, but rather were revealed during one-on-one interviews with students at the end of the semester. A subset of students in the experimental group produced superior answers to some higher-order interview questions as compared with students in the control group. During the interview, students in both groups preferred to use either the hand-held models alone or in combination with the PE imaging program. Students typically did not use any tools when answering knowledge (lower-level thinking) questions, but when challenged with higher-level thinking questions, students in both the control and experimental groups elected to use the models. (Contains 6 tables and 2 figures.)

Forest-based industries produce huge quantities of bark during their primary processing activities. In Nordic pulp and paper industries, where a wet debarking process is used for bark removal, toxic debarking water and bark press water are produced as a by-product. However, polyphenols represent an important fraction of the debarking water and bark press water. These polyphenolic compounds are of commercial interest in chemical specialty sectors since polyphenols have been proven to have diverse health benefits, and after collecting them from waste sources, they can act as alternatives to oil-based chemicals. Determining the economic potential of polyphenolic compounds, identifying their molecular structure, and determining the antioxidant capacity of these compounds present in debarking water and bark can support the identification of their potential applications. The results show that water extractions from bark have a lower efficiency than (partial) alcoholic extractions. Nevertheless, a considerable amount of low-molecular polyphenolic compounds, which are of interest for high-end applications, was found in all extracts. Bark press water has a highly versatile range of polyphenolic compounds and showed some antioxidant activity, making it a great source for the collection of polyphenolic compounds, in contrast to debarking water, which had a much lower polyphenolic content and low antioxidant activity. [ABSTRACT FROM AUTHOR]

Paper material produced after about 1850 contains additives that cause progressive acidification of the cellulose matrix, which can result in severe degradation of the material and simultaneous deterioration in its strength properties. This problem has affected whole stocks of libraries and archives, in response to which the process of 'mass deacidification' has been developed. In this study, the structure and chemistry of the active reagent used in the main variant of this process has been identified as magnesium n-propoxycarbonate. The reagent, introduced in an inert fluorinated solvent, neutralizes acids in the paper matrix and simultaneously deposits a reserve of alkaline magnesium salts that counteract re-acidification. At the same time, it is much less alkaline than the magnesium alcoholates so that alkali-induced degradation reactions of cellulose (β-alkoxy elimination) are avoided. [ABSTRACT FROM AUTHOR]

Teaching chemistry and biology students about biologics design remains challenging despite its increasing importance in pharmaceutical development. Monoclonal antibodies, commonly called mAbs, are the most popular biologics. They have been developed into drugs to treat various diseases in the past decades. Multiple challenges exist for designing proper formulations to stabilize mAbs, such as preventing aggregation and mitigating viscosity. Molecular modeling and simulations can improve pharmaceutical products by examining the interactions between mAbs and other compounds, such as excipients. To introduce students to biopharmaceuticals, eight students at the Stevens Institute of Technology participated in a semester-long course to learn the challenges of pharmaceutical development and different computational skills to study biologics design. The students started with a limited background in this field. Throughout one semester, they were introduced to various literature and software tools for modeling antibodies and studying their interactions with excipients. This paper aims to develop a course structure to be replicated at other universities and institutions to teach biopharmaceutical development to students.

The factors affecting the migration of organic contaminants from paper packaging materials into packaged dry powdered food were studied. Based on the molecular structure, volatile, molecular weight, and harm posed to the human body, five organic substances were selected as simulated pollutants. According to EU technical standard BS EN13130-1:2004 (E) migration trough types E manufactured migration cell and completion of migration of simulated contaminants from paper to solid powdered foods at different temperature and times were studied. GC-MS technology was used to detect the content of simulated pollutants in paper and food. Partial least-squares (PLS) method was used to analyze the effects of various factors affecting migration performance. Results showed that the migration of simulated pollutants from paper packaging materials into solid powdered foods was affected by temperature, contact time, molecular weight of organic pollutants, and volatile. Among them, volatile and molecular weight contributed the greatest effects, whereas temperature contributed the least effect. Changes in temperature and contact time were positively correlated with migration performance, whereas volatile, molecular weight, molecular polarity of organic pollutants were negatively correlated. In other words, for the individual factors, higher temperature and longer contact time meant higher migration percentage of organic pollutants from paper-based packaging to packaged dry powdered foods, whereas greater volatile and higher molecular weight of organic pollutants led to poorer migration into food. • The migration of organic contaminants from paper-based packaging materials to packaged dry powdered foods. • The main factors affecting migration behavior. • The relevance and weight of these factors. [ABSTRACT FROM AUTHOR]