Statistical correlation between enterovirus genome copy numbers and infectious viral particles in wastewater samples

Aims: Classic virological tests are time consuming and labour-intensive; realtime RT-PCR has proven to be a fast method to detect and quantify enterovirus genomes in clinical and environmental samples. This method is unable to discriminate between infective and noninfective enterovirus particles; few clinical studies have compared real-time RT-PCR and viral culture. We wondered if the enterovirus genome quantification could be correlated to the infectivity. Methods and Results: We used the statistical approach to verify our hypotheses to correlate data, obtained by the standard method (most probable number of cytopathic units—MPNCU) and molecular test (real-time RT-PCR), on wastewater treatment plant samples. Chi-squared test was used, considering several cut-off values (‘50’-‘100’-‘200’ genome copy numbers), to determine statistical significance in comparison of the two methods. Chi-square value was not significant when cut-off of 50 (P = 0Æ103) and 100 (P = 0Æ178) was assumed but was significant with cut-off of 200 (P = 0Æ044). Conclusion: This limit, 200 genome copy, could be used as cut-off value to indicate enterovirus survival in environmental monitoring. Significant and Impact of the Study: To introduce a fast procedure that is able to compensate for disadvantages of cell culture method for viral environmental analyses

Are PEI-coated SWCNTs conjugated with hepatitis A virus? A chemical study with SEM, Z-potential, EDXD and RT-PCR

The conjugation between nanotubes, coated with different doses of polyethylene imine (PEI) and hepatitis A virus (HAV) was investigated by scanning electron microscopy, Z-potential, thermogravimetric and differential thermal analysis, transmission electron microscopy, energy dispersive x-ray diffraction (EDXD) and reverse transcript polymerase chain reaction (RT-PCR). For the first time, to our knowledge, evidence is obtained that conjugation between the nanotubes and the HAV occurs and that it has an (at least a partial) electrostatic character. Since all components of the conjugated systems, nanotubes, coating material and virus are characterized by different peak shapes in the selected q range, it was possible to infer that conjugation occurred. RT-PCR measurements confirmed that the conjugation of the coated nanotubes and HAV occurred and the result was stable. This opens up the prospect of probing the coated nanotubes as intra-cellular carriers in transfection processes of the virus. Further biological applications will concern a possible vaccine especially for non-replicative viruses

The Springback: Account book binding

These instructions for making a springback account book are derived from my notes as an apprentice at the Kunstbuchbinderei Klein, with adaptations over time. While my training is in the German tradition, the steps outlined should not be radically different from the English tradition. Although the technique was originally patented in Great Britain in 1799 by John and Joseph Williams,) the authors have found very few descriptions of this method in contemporary English language texts. Alex J. Vaughan describes the technique with great detail in Section II, \u27Stationery Binding\u27 of Modern Bookbinding. There is also an historical mention in Bernard Middleton\u27s A History of English Craft Bookbinding, but it does not detail the steps required to complete a binding. The German binding literature, however, covers the springback quite thoroughly in such texts as Thorwald Henningsen, Paul Kersten, Heinrich Luers, Gustav Moessner, Fritz Wiese, and Gerhard Zahn, and the technique is still required learning for all hand bookbinding apprentices in Germany. As a style, the springback is firmly rooted in the \u27trade\u27 binding tradition. The springback\u27s robustness, and ability to lie open and flat for extended periods of time without unduly stressing the spine make the structure ideal for use as account and record books. These same qualities make it suitable for guest-books, lectern Bibles, and similarly used books. Regrettably the structure is rarely found on fine bindings or in contemporary book art, especially as the structure would be a suitable platform for many elements of design bindings. Its thick boards would provide a canvas for more sculptural or inset designs. With some minor modification it could also serve as a means of presenting pop-up constructions

Macrocyclic colibactin induces DNA double-strand breaks via copper-mediated oxidative cleavage.

Colibactin is an assumed human gut bacterial genotoxin, whose biosynthesis is linked to the clb genomic island that has a widespread distribution in pathogenic and commensal human enterobacteria. Colibactin-producing gut microbes promote colon tumour formation and enhance the progression of colorectal cancer via cellular senescence and death induced by DNA double-strand breaks (DSBs); however, the chemical basis that contributes to the pathogenesis at the molecular level has not been fully characterized. Here, we report the discovery of colibactin-645, a macrocyclic colibactin metabolite that recapitulates the previously assumed genotoxicity and cytotoxicity. Colibactin-645 shows strong DNA DSB activity in vitro and in human cell cultures via a unique copper-mediated oxidative mechanism. We also delineate a complete biosynthetic model for colibactin-645, which highlights a unique fate of the aminomalonate-building monomer in forming the C-terminal 5-hydroxy-4-oxazolecarboxylic acid moiety through the activities of both the polyketide synthase ClbO and the amidase ClbL. This work thus provides a molecular basis for colibactin's DNA DSB activity and facilitates further mechanistic study of colibactin-related colorectal cancer incidence and prevention

Navigating through the COVID-19 pandemic. Unfinished learning in primary and secondary education in Tunisia

During the outbreak of the global SARS-CoV-2 (COVID-19) pandemic, Tunisia, like many countries, prepared an emergency plan to shift to distance learning to salvage the academic year and ensure continuous learning. However, a shortage of digital materials coupled with the fact that many households did not have adequate Internet bandwidth made it virtually impossible to secure adequate digital learning. When in-person schooling was restarted in 2020/21, primary, pre-secondary, and secondary school pupils attended school on alternate days to avoid overcrowding. As a result of the pandemic, the curriculum has been lightened, and the fundamentals have been prioritized. Based on a content analysis of the Ministry of Education documents and a survey conducted by the Ministry on remote learning, we shed light on the different measures taken to curb learning loss during the spread of the pandemic as well as the challenges facing Tunisian students and the government. The consequences of these measures are discussed along with future recommendations. (DIPF/Orig.

Polyester Encapsulation Using An Edge Welder

Step-by-step instructions for encapsulating documents and other flat paper-based items in polyester film (mylar) using an edge welder

Phase Box

The phase box is a simple, low-cost, enclosure made from 20pt acid-free folder stock. It is designed to protect brittle, deteriorated, low priority items

Drop Spine Box

Step-by-step instructions for measuring and assembling a drop-spine box for the housing or rare books and other materials