Multi-layer hydrogen-barrier coating for natural gas transmission pipelines

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Mathematical Representations in a Synchronous Online Mathematics Specialist Preparation Program

Universities are implementing more online courses (Yamagata-Lynch, 2014). However, instructors may feel a sense of trepidation in transitioning a mathematics class to a synchronous online platform because they do not want to compromise quality pedagogy (Herrington et al., 2001) for the convenience of an online environment (Wills, 2021). Some courses have successfully transitioned to a synchronous online environment while maintaining rich discussion and student collaboration (Baker & Hjalmarson, 2019); however, mathematics content courses include the additional challenge of incorporating problem solving with multiple representations. This paper focuses on how mathematical representations emerge in a synchronous online course for mathematics specialists

Applications of high resolution mid-infrared spectroscopy for atmospheric and environmental measurements

For the past 20 years, high resolution infrared spectroscopy has served as a valuable tool to measure gas-phase concentrations of ambient gas samples. We review recent advances in atmospheric sampling using direct absorption high resolution mid-infrared spectroscopy from the perspective of light sources, detectors, and optical designs. Developments in diode, quantum cascade and interband cascade laser technology have led to thermoelectrically-cooled single-mode laser sources capable of operation between 800 \wn and 3100 \wn, with \textless10 MHz resolution and \textgreater10 mW power. Advances in detector and preamplifier technology have yielded thermoelectriocally-cooled sensors capable of room-temperature operation with extremely high detectivities. Finally, novel spectrometer optical designs have led to robust multipass absorption cells capable of \textgreater400 m effective pathlength in a compact package. In combination with accurate spectroscopic databases, these developments have afforded dramatic improvements in measurement sensitivity, accuracy, precision, and selectivity. We will present several examples of the applications of high resolution mid-IR spectrometers in real-world field measurements at sampling towers and aboard mobile platforms such as vehicles and airplanes

The relationship between technical high school brazilian students' working memory capacity, pre-reading activities, and unference generation in reading comprehension in L2

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Inglês: Estudos Linguísticos e Literários, Florianópolis, 2017.Abstract : This research aimed at investigating whether there is a relationship between Technical High School Brazilian students? Working Memory capacity, the use of pre-reading activities, and inference generation in reading comprehension in L2. A group of 36 students from the third year of the Technical High School Course (Técnico em Agropecuária Integrado ao Ensino Médio) at Instituto Federal do Rio Grande do Sul (IFRS), Campus Sertão, participated in this study. Participants were mostly beginner/ pre-intermediate speakers of English as an L2. The instruments used in this study were a reading proficiency test; the Reading Span Test (RST); four pre-reading activities; two texts, being one narrative and one expository text; the Pause Protocol; two sets of comprehension questions (one for each text); a reader?s profile and a retrospective questionnaire. Participants were divided into two groups, according to the pre-reading activity developed (Group I was exposed to the pre-reading activity only previous to the expository text, while Group II was exposed to the pre-reading activity only before the reading of the narrative text, but not the expository one). Participants? WMC was assessed through the RST. Participants? reports from the Pause Protocol were transcribed and their utterances were categorized in accordance with Narvaez et al.?s (1999) Inference Categorization Model. Moreover, participants? answers in the reading comprehension questions were analyzed and scored. Participants? answers from the reader profile and retrospective questionnaires were also helpful in clarifying this study?s results. Data were analyzed both qualitatively and quantitatively, and the main results show that WMC positively correlates with reading comprehension, and also with explanatory inferences, which are strictly connected to reading comprehension. Furthermore, this study provides evidence to the claim that narratives are easier to comprehend than expository texts, because participants? performance was better on the reading comprehension questions related to the narrative text, when compared with the expository one. More skilled readers presented the greatest incidence of explanatory inferences, which is associated with reading comprehension. Findings also confirm the importance of the use of pre-reading activities, that in this study activated readers? schemata and increased reading comprehension. Furthermore, the use of pre-reading activities positively influenced the number and quality of the inferences generated by participants. It is believed that as inference generation helps students to construct meaning from texts, understanding how low and high span readers generate inferences, and how inference generation affects comprehension can help teachers to assist their students, aiding them to become more proficient readers. Moreover, understanding the importance of pre-reading activities for reading comprehension and inference generation and also their possible effect on reducing the demands on working memory capacity during reading may help teachers to prepare classes that better fit the student?s needs.Esta pesquisa teve como objetivo investigar se existe uma relação entre a Capacidade de Memória de Trabalho de estudantes do Ensino Médio Técnico, o uso de atividades de pré-leitura e a geração de inferências na compreensão leitora em L2. Um grupo de 36 alunos do terceiro ano do Curso Técnico em Agropecuária Integrado ao Ensino Médio do Instituto Federal do Rio Grande do Sul (IFRS) - Campus Sertão participaram deste estudo. Os participantes eram, majoritariamente, falantes iniciantes / pré-intermediários de inglês como L2. Os instrumentos utilizados neste estudo foram um teste de proficiência em leitura; o Teste de Capacidade de Leitura (Reading Span Test); quatro atividades de pré-leitura; dois textos, sendo um narrativo e um expositivo; o Protocolo Pausa; dois conjuntos de perguntas de compreensão (um para cada texto); um perfil do leitor e um questionário retrospectivo. Os participantes foram divididos em dois grupos, de acordo com a atividade de pré-leitura desenvolvida (o Grupo I foi exposto à atividade de pré-leitura apenas antes de ler o texto expositivo, enquanto o Grupo II foi exposto à atividade de pré-leitura apenas antes de ler o texto narrativo, mas não o expositivo). A Capacidade de Memória de Trabalho dos participantes foi avaliada através do Teste de Capacidade de Leitura (Reading Span Test). As verbalizações realizadas pelos participantes durante o Protocolo de Pausa foram transcritas e categorizadas de acordo com o Modelo de Categorização de Inferências proposto por Narvaez et al. (1999). Além disso, as respostas dos participantes às perguntas de compreensão foram analisadas e avaliadas. As respostas fornecidas pelos participantes no perfil do leitor e no questionário retrospectivo também foram úteis para esclarecer os resultados deste estudo. Os dados foram analisados de forma qualitativa e quantitativa, e os principais resultados mostram que a Capacidade de Memória de Trabalho se correlaciona positivamente com a compreensão leitora e também com inferências explicativas, que estão diretamente ligadas à compreensão. Além disso, este estudo fornece evidências que textos narrativos são mais fáceis de compreender do que textos expositivos, visto que o desempenho dos participantes foi melhor nas perguntas de compreensão relacionadas ao texto narrativo, quando comparadas ao expositivo. Os melhores leitores apresentaram a maior incidência de inferências explicativas, que está associada à compreensão leitora. As conclusões também apontam para a importância do uso de atividades de pré-leitura, que neste estudo ativaram os esquemas dos leitores e aumentaram a compreensão. Além disso, o uso de atividades de pré-leitura influenciou positivamente a quantidade e a qualidade das inferências geradas pelos participantes. Acredita-se que, uma vez que a geração de inferência auxilia os estudantes na construção de significado a partir de textos, entender como leitores com diferentes capacidades de memória de trabalho geram inferências e como a geração de inferências afeta a compreensão pode auxiliar os professores a tornar seus alunos leitores mais proficientes. Além disso, entender a importância das atividades de pré-leitura para a compreensão e geração de inferências, além de seu possível efeito na redução das demandas de capacidade de memória de trabalho durante a leitura, pode ajudar os professores a preparar aulas que melhor se adaptem às necessidades dos alunos

Chromosome Bridges Maintain Kinetochore-Microtubule Attachment throughout Mitosis and Rarely Break during Anaphase

Accurate chromosome segregation during cell division is essential to maintain genome stability, and chromosome segregation errors are causally linked to genetic disorders and cancer. An anaphase chromosome bridge is a particular chromosome segregation error observed in cells that enter mitosis with fused chromosomes/sister chromatids. The widely accepted Breakage/Fusion/Bridge cycle model proposes that anaphase chromosome bridges break during mitosis to generate chromosome ends that will fuse during the following cell cycle, thus forming new bridges that will break, and so on. However, various studies have also shown a link between chromosome bridges and aneuploidy and/or polyploidy. In this study, we investigated the behavior and properties of chromosome bridges during mitosis, with the idea to gain insight into the potential mechanism underlying chromosome bridge-induced aneuploidy. We find that only a small number of chromosome bridges break during anaphase, whereas the rest persist through mitosis into the subsequent cell cycle. We also find that the microtubule bundles (k-fibers) bound to bridge kinetochores are not prone to breakage/detachment, thus supporting the conclusion that k-fiber detachment is not the cause of chromosome bridge-induced aneuploidy. Instead, our data suggest that while the microtubules bound to the kinetochores of normally segregating chromosomes shorten substantially during anaphase, the k-fibers bound to bridge kinetochores shorten only slightly, and may even lengthen, during anaphase. This causes some of the bridge kinetochores/chromosomes to lag behind in a position that is proximal to the cell/spindle equator and may cause the bridged chromosomes to be segregated into the same daughter nucleus or to form a micronucleus

Contaminanti nello zooplancton

Not availableContaminanti nello zooplancton nell\u27ambito del progetto di ricerca "Indagini su DDT e sostanze pericolose nell\u27ecosistema del Lago Maggiore"

Staphylococcus aureus persistence in osteocytes: weathering the storm of antibiotics and autophagy/xenophagy

Staphylococcus aureus is a major causative pathogen of osteomyelitis. Intracellular infections of resident bone cells including osteocytes can persist despite gold-standard clinical intervention. The mechanisms by which intracellular S. aureus evades antibiotic therapy are unknown. In this study, we utilised an in vitro S. aureus infection model of human osteocytes to investigate whether antibiotic-mediated dysregulation of autophagy contributes to this phenomenon. Infected or non-infected osteocyte-like cells were exposed to combinations of rifampicin, vancomycin, and modulators of autophagy. Intracellular bacterial growth characteristics were assessed using colony-forming unit (CFU) analysis, viable bacterial DNA abundance, and the rate of escape into antibiotic-free medium, together with measures of autophagic flux. Rifampicin, alone or in combination with vancomycin, caused a rapid decrease in the culturability of intracellular bacteria, concomitant with stable or increased absolute bacterial DNA levels. Both antibiotics significantly inhibited autophagic flux. However, modulation of autophagic flux did not affect viable bacterial DNA levels. In summary, autophagy was shown to be a factor in the host–pathogen relationship in this model, as its modulation affected the growth state of intracellular S. aureus with respect to both their culturability and propensity to escape the intracellular niche. While rifampicin and vancomycin treatments moderately suppressed autophagic flux acutely, this did not explain the paradoxical response of antibiotic treatment in decreasing S. aureus culturability whilst failing to clear bacterial DNA and hence intracellular bacterial load. Thus, off-target effects of rifampicin and vancomycin on autophagic flux in osteocyte-like cells could not explain the persistent S. aureus infection in these cells

CENP-F stabilizes kinetochore-microtubule attachments and limits dynein stripping of corona cargoes

Accurate chromosome segregation demands efficient capture of microtubules by kinetochores and their conversion to stable bioriented attachments that can congress and then segregate chromosomes. An early event is the shedding of the outermost fibrous corona layer of the kinetochore following microtubule attachment. Centromere protein F (CENP-F) is part of the corona, contains two microtubule-binding domains, and physically associates with dynein motor regulators. Here, we have combined CRISPR gene editing and engineered separation-of-function mutants to define how CENP-F contributes to kinetochore function. We show that the two microtubule-binding domains make distinct contributions to attachment stability and force transduction but are dispensable for chromosome congression. We further identify a specialized domain that functions to limit the dynein-mediated stripping of corona cargoes through a direct interaction with Nde1. This antagonistic activity is crucial for maintaining the required corona composition and ensuring efficient kinetochore biorientation

Determining the suitability of mass spectrometry for understanding the dissolution processes involved with pharmaceutical tablets

RATIONALE: A current challenge for analytical chemists is the development of measurement systems and approaches required to understand dynamic processes such as tablet dissolution. The design and development of oral tablets could be improved by the availability of detailed information about the rates of release of the individual tablet components. Small footprint mass spectrometry (MS) systems are gaining use for on-line reaction monitoring because of their ability to rapidly determine multiple reactant, intermediate, and product species. We have therefore assessed the utility of such MS systems to the study of dissolution processes. METHODS: Aqueous dissolution media containing phosphate and other non volatile buffer salts were pumped from a standard USPII dissolution vessel through an active splitter and back. The splitter sampled the dissolution stream and diluted it into a make-up flow which was pumped to a small single quadrupole mass spectrometer. Single ion monitoring was used to quantify the ions of interest. Three different bio-relevant dissolution media were studied to gauge the impact of the sample matrix. RESULTS: Individual dissolution profiles were obtained from a tablet containing three drugs and lactose as the soluble filler. This was successfully demonstrated with three different bio-relevant media designed to reflect the pH of the different sections of the human gastro-intestinal tract. Component concentrations as low as 0.06 μg/mL (representing 1% dissolution) were detected. The MS dissolution profiles correlated with the visual observation of tablet dissolution. MS gave linear responses with concentration for the individual components, although analysis of the tablet solution indicated that ion suppression is an area for further investigation CONCLUSIONS: An on-line MS system was used to determine the individual dissolution profiles of three drugs and lactose as they are released from the same tablet. The level of each of these components in solution was determined every 10 seconds, and each had a similar release profile. The dissolution profiles were determined using inorganic buffer solutions at three different bio-relevant pHs