Desktop Video Conferencing Tools in HigherEducation: Understanding Lecturers’ Experience

Technological advancements facilitate new ways of conducting university lectures. Through Emergency Remote Teaching (ERT), Desktop Video Conferencing Tools (DVCT) have been adopted by higher education institutions to face the challenges of the COVID-19 pandemic. DVCT enables online, real-time education to be delivered. To understand educators’ experience with DVCT, an online survey was con-ducted among lecturers (N = 243) at the University of Bergen (UiB) between October 12-29th 2020. In this empirical paper, we report on the findings from the Likert scale and free text questions, analyzed using quantitative and qualitative approaches. Elaborate qualitative data (18,107 words) was gathered, providing perspectives of lecturers’ experiences. The main advantages of DVCT identified are flexibility and accessibility. Disadvantages concern poor student communication and interaction. Overall, the trend is mixed to low sentiments towards lecturing with DVCT, despite lecturers claiming to be confident in using new digital tools. Lecturers’ experience with DVCT may be positively affected by providing them with training, emphasizing pedagogical aspects, accepting the shortcomings of ERT, and recognizing that digitalization encompasses adapting to new technologies as well as changing practices, planning, and execution

Dielectric spectroscopy of water at low frequencies: The existence of an isopermitive point

We have studied the real part of the dielectric constant of water from 100 Hz to 1 MHz. We have found that there is a frequency where the dielectric constant is independent of temperature, and called this the isopermitive point. Below this point the dielectric constant increases with temperature, above, it decreases. To understand this behavior, we consider water as a system of two species: ions and dipoles. The first give rise to the so called Maxwell-Wagner-Sillars effect, the second obey the Maxwell-Boltzmann statistics. At the isopermitive point the effect of both mechanisms in the dielectric response compensate each other.Comment: 4 pages, 4 figures, submitted to Chem. Phys. Let

Organization of the cpe Locus in CPE-Positive Clostridium perfringens Type C and D Isolates

Clostridium perfringens enterotoxin (encoded by the cpe gene) contributes to several important human, and possibly veterinary, enteric diseases. The current study investigated whether cpe locus organization in type C or D isolates resembles one of the three (one chromosomal and two plasmid-borne) cpe loci commonly found amongst type A isolates. Multiplex PCR assays capable of detecting sequences in those type A cpe loci failed to amplify products from cpe-positive type C and D isolates, indicating these isolates possess different cpe locus arrangements. Therefore, restriction fragments containing the cpe gene were cloned and sequenced from two type C isolates and one type D isolate. The obtained cpe locus sequences were then used to construct an overlapping PCR assay to assess cpe locus diversity amongst other cpe-positive type C and D isolates. All seven surveyed cpe-positive type C isolates had a plasmid-borne cpe locus partially resembling the cpe locus of type A isolates carrying a chromosomal cpe gene. In contrast, all eight type D isolates shared the same plasmid-borne cpe locus, which differed substantially from the cpe locus present in other C. perfringens by containing two copies of an ORF with 67% identity to a transposase gene (COG4644) found in Tn1546, but not previously associated with the cpe gene. These results identify greater diversity amongst cpe locus organization than previously appreciated, providing new insights into cpe locus evolution. Finally, evidence for cpe gene mobilization was found for both type C and D isolates, which could explain their cpe plasmid diversity

Carbon Nanotubes by a CVD Method. Part I: Synthesis and Characterization of the (Mg, Fe)O Catalysts

The controlled synthesis of carbon nanotubes by chemical vapor deposition requires tailored and wellcharacterized catalyst materials. We attempted to synthesize Mg1-xFexO oxide solid solutions by the combustion route, with the aim of performing a detailed investigation of the influence of the synthesis conditions (nitrate/urea ratio and the iron content) on the valency and distribution of the iron ions and phases. Notably, characterization of the catalyst materials is performed using 57Fe Mo¨ssbauer spectroscopy, X-ray diffraction, and electron microscopy. Several iron species are detected including Fe2+ ions substituting for Mg2+ in the MgO lattice, Fe3+ ions dispersed in the octahedral sites of MgO, different clusters of Fe3+ ions, and MgFe2O4-like nanoparticles. The dispersion of these species and the microstructure of the oxides are discussed. Powders markedly different from one another that may serve as model systems for further study are identified. The formation of carbon nanotubes upon reduction in a H2/CH4 gas atmosphere of the selected powders is reported in a companion paper

Genetic characterization of type A enterotoxigenic Clostridium perfringens strains

Clostridium perfringens type A, is both a ubiquitous environmental bacterium and a major cause of human gastrointestinal disease, which usually involves strains producing C. perfringens enterotoxin (CPE). The gene (cpe) encoding this toxin can be carried on the chromosome or a large plasmid. Interestingly, strains carrying cpe on the chromosome and strains carrying cpe on a plasmid often exhibit different biological characteristics, such as resistance properties against heat. In this study, we investigated the genetic properties of C. perfringens by PCR-surveying 21 housekeeping genes and genes on representative plasmids and then confirmed those results by Southern blot assay (SB) of five genes. Furthermore, sequencing analysis of eight housekeeping genes and multilocus sequence typing (MLST) analysis were also performed. Fifty-eight C. perfringens strains were examined, including isolates from: food poisoning cases, human gastrointestinal disease cases, foods in Japan or the USA, or feces of healthy humans. In the PCR survey, eight of eleven housekeeping genes amplified positive reactions in all strains tested. However, by PCR survey and SB assay, one representative virulence gene, pfoA, was not detected in any strains carrying cpe on the chromosome. Genes involved in conjugative transfer of the cpe plasmid were also absent from almost all chromosomal cpe strains. MLST showed that, regardless of their geographic origin, date of isolation, or isolation source, chromosomal cpe isolates, i) assemble into one definitive cluster ii) lack pfoA and iii) lack a plasmid related to the cpe plasmid. Similarly, independent of their origin, strains carrying a cpe plasmid also appear to be related, but are more variable than chromosomal cpe strains, possibly because of the instability of cpe-borne plasmid(s) and/or the conjugative transfer of cpe-plasmid(s) into unrelated C. perfringens strains. © 2009 Deguchi et al

Isolation and characterization of a new [FeFe]-hydrogenase from Clostridium perfringens

© 2015 International Union of Biochemistry and Molecular Biology, Inc. This paper reports the first characterization of an [FeFe]-hydrogenase from a Clostridium perfringens strain previously isolated in our laboratory from a pilot-scale bio-hydrogen plant that efficiently produces H2 from waste biomasses. On the basis of sequence analysis, the enzyme is a monomer formed by four domains hosting various iron–sulfur centres involved in electron transfer and the catalytic center H-cluster. After recombinant expression in Escherichia coli, the purified protein catalyzes H2 evolution at high rate of 1645±16s−1. The optimal conditions for catalysis are in the pH range 6.5–8.0 and at the temperature of 50°C. EPR spectroscopy showed that the H-cluster of the oxidized enzyme displays a spectrum coherent with the Hox state, whereas the CO-inhibited enzyme has a spectrum coherent with the Hox-CO state. FTIR spectroscopy showed that the purified enzyme is composed of a mixture of redox states, with a prevalence of the Hox; upon reduction with H2, vibrational modes assigned to the Hred state were more abundant, whereas binding of exogenous CO resulted in a spectrum assigned to the Hox-CO state. The spectroscopic features observed are similar to those of the [FeFe]-hydrogenases class, but relevant differences were observed given the different protein environment hosting the H-cluster

Necrotic Enteritis-Derived Clostridium perfringens Strain with Three Closely Related Independently Conjugative Toxin and Antibiotic Resistance Plasmids

The pathogenesis of avian necrotic enteritis involves NetB, a pore-forming toxin produced by virulent avian isolates of Clostridium perfringens type A. To determine the location and mobility of the netB structural gene, we examined a derivative of the tetracycline-resistant necrotic enteritis strain EHE-NE18, in which netB was insertionally inactivated by the chloramphenicol and thiamphenicol resistance gene catP. Both tetracycline and thiamphenicol resistance could be transferred either together or separately to a recipient strain in plate matings. The separate transconjugants could act as donors in subsequent matings, which demonstrated that the tetracycline resistance determinant and the netB gene were present on different conjugative elements. Large plasmids were isolated from the transconjugants and analyzed by high-throughput sequencing. Analysis of the resultant data indicated that there were actually three large conjugative plasmids present in the original strain, each with its own toxin or antibiotic resistance locus. Each plasmid contained a highly conserved 40-kb region that included plasmid replication and transfer regions that were closely related to the 47-kb conjugative tetracycline resistance plasmid pCW3 from C. perfringens. The plasmids were as follows: (i) a conjugative 49-kb tetracycline resistance plasmid that was very similar to pCW3, (ii) a conjugative 82-kb plasmid that contained the netB gene and other potential virulence genes, and (iii) a 70-kb plasmid that carried the cpb2 gene, which encodes a different pore-forming toxin, beta2 toxin

Conjugative Botulinum Neurotoxin-Encoding Plasmids in Clostridium botulinum

Clostridium botulinum produces seven distinct serotypes of botulinum neurotoxins (BoNTs). The genes encoding different subtype neurotoxins of serotypes A, B, F and several dual neurotoxin-producing strains have been shown to reside on plasmids, suggesting that intra- and interspecies transfer of BoNT-encoding plasmids may occur. The objective of the present study was to determine whether these C. botulinum BoNT-encoding plasmids are conjugative.C. botulinum BoNT-encoding plasmids pBotCDC-A3 (strain CDC-A3), pCLJ (strain 657Ba) and pCLL (strain Eklund 17B) were tagged with the erythromycin resistance marker (Erm) using the ClosTron mutagenesis system by inserting a group II intron into the neurotoxin genes carried on these plasmids. Transfer of the tagged plasmids from the donor strains CDC-A3, 657Ba and Eklund 17B to tetracycline-resistant recipient C. botulinum strains was evaluated in mating experiments. Erythromycin and tetracycline resistant transconjugants were isolated from donor:recipient mating pairs tested. Transfer of the plasmids to the transconjugants was confirmed by pulsed-field gel electrophoresis (PFGE) and Southern hybridizations. Transfer required cell-to-cell contact and was DNase resistant. This indicates that transfer of these plasmids occurs via a conjugation mechanism.This is the first evidence supporting conjugal transfer of native botulinum neurotoxin-encoding plasmids in C. botulinum, and provides a probable mechanism for the lateral distribution of BoNT-encoding plasmids to other C. botulinum strains. The potential transfer of C. botulinum BoNT-encoding plasmids to other bacterial hosts in the environment or within the human intestine is of great concern for human pathogenicity and necessitates further characterization of these plasmids

Kapitalinnflyt til vekstland : push- eller pullfaktorer? : en empirisk analyse

Volumet av bilaterale kapitalinnstrømmer til vekstland nådde et historisk toppunkt i 2007. Da finanskrisen inntraff snudde kapitalstrømmene og fant nå veien til industriland. I gjennopphentingen etter krisen har et betydelig volum av kapital på nytt strømmet til vekstlandene. Frykt for at kapitalstrømmene skal skape bobledannelser og ustabilitet i vekstlands økonomier, har satt fokus på hvilke faktorer som påvirker kapitalinnstrømninger til denne gruppen land. Beslutningstakere i vekstland har argumentert for at innstrømningen skyldes globale pushfaktorer, samtidig som beslutningstakere i industriland argumenterer for pullfaktorer. Denne utredningen analyserer faktorer som forklarer kapitalinnflyt til vekstland. Ved å anvende regresjonsanalyse på paneldata for 25 vekstland, analyseres tre forskjellige kapitalinnstrømmer basert på en ”push og pull” tilnærming. Her skilles det mellom interne landsspesifikke faktorer og eksterne globale faktorer for å forklare kapitalbevegelsene over tidsperioden 2002 til 2012. Våre resultater viser at kapitalinnflyt til vekstland er påvirket av pullfaktorene: grad av utviklet finansielt marked, infrastruktur, nasjonal kredittrate, institusjoner, åpenhet, forventet fremtidig vekst og valutaintervensjoner; pushfaktorene: risikoholdning og global likviditet; samt de kombinerte faktorene: vekst- og rentedifferanse. Vår forskning indikerer at både push- og pullfaktorer har vært viktige for å forklare kapitalinnstrømninger til vekstland. For total kapitalinnflyt og direkte utenlandske investeringer har en kombinasjon av push- og pullfaktorer vært sentrale. For porteføljeinvesteringer kan innflyten av kapital, i perioden før finanskrisen, tilskrives pullfaktorer. Etter krisen finner vi imidlertid at det er pushfaktorer som dominerer. Fra perioden før til etter finanskrisen har det skjedd en signifikant endring i hva som forklarer kapitalinnflyten til vekstland. For porteføljeinvesteringer ble en signifikant endring påvist for begge pushvariablene. Dette støtter opp om at porteføljeinvesteringer, som før kunne tilskrives pullfaktorer, nå domineres av pushfaktorer

Tvilling-tvilling transfusjon syndrom. Årsak og behandling.

Objective: The aim of this review was to present different treatment options for pregnancies diagnosed with twin to twin transfusion syndrome (TTTS) and compare them to each other. Background: Twin to twin transfusion syndrome is a rare and serious complication affecting 5,5-17% of all monozygotic, monochorionic, diamniotic twin pregnancies. Without treatment TTTS is associated with a high risk of fetal and neonatal mortality and morbidity. Treatment options include expectant management, amnionreduction, septostomy, selective feticide, fetoscopic laser ablation, preterm delivery (after week 35) and medications. Amnionreduction and fetoscopic laser ablation are the treatment options most used and discussed. Method: Literature searches in Cochrane library, Ovid, Up-to-date and Pubmed were performed in the period March 2010 – August 2011. We chose to include articles from 1990-2011 using relevant key words concentrating on pathogenesis, treatment and prognosis. A total of 26 articles were reviewed. Result and Conclusion: TTTS is a complex and unpredictable syndrome and choice of treatment must be taken after determining at what stage TTTS is present and how far the pregnancy has proceeded. There is an ongoing discussion about what the treatment of choice should be, as the knowledge of the syndrome and longterm prognosis is increasing and the surgical techniques developes. Laser ablation, being the only curative treatment, is widely accepted as the treatment of choice for women with stage II-IV TTTS between week 16-26