Analysis of friction coefficient for a base steel 5 % Cr, applying variable loads of 196 N, 294 N and 392 N, and speeds of 0,18 m/sec, 0,36 m/sec and 0,54 m/sec

The present study consists in analyzing the friction coefficient as a variable of the normal load and slip speed for 5% Cr steel, by applying the Block-on-Disk method according to ASTM D2714. The friction coefficient increases linearly 23,25 % from 0,214 to 0,266 when the load is increased from 196 N to 392 N; the same phenomenon is observed when the friction coefficient increases 47,82 % from 0,23 to 0,34 when the slip speed increases from 0,18 m/sec to 0,54 m/sec. The friction coefficient increased by 23,25 % for an increase in the load from 196 N to 392 N, which corresponds to 100 %, while an increase of the friction coefficient of 47,82 % occurred by increasing the speed from 0,18 m/sec to 0,54 m/sec which corresponds to 200 %

Perforin gene transfer into hematopoietic stem cells improves immune dysregulation in murine models of perforin deficiency

Defects in perforin lead to the failure of T and NK cell cytotoxicity, hypercytokinemia, and the immune dysregulatory condition known as familial hemophagocytic lymphohistiocytosis (FHL). The only curative treatment is allogeneic hematopoietic stem cell transplantation which carries substantial risks. We used lentiviral vectors (LV) expressing the human perforin gene, under the transcriptional control of the ubiquitous phosphoglycerate kinase promoter or a lineage-specific perforin promoter, to correct the defect in different murine models. Following LV-mediated gene transfer into progenitor cells from perforin-deficient mice, we observed perforin expression in mature T and NK cells, and there was no evidence of progenitor cell toxicity when transplanted into irradiated recipients. The resulting perforin-reconstituted NK cells showed partial recovery of cytotoxicity, and we observed full recovery of cytotoxicity in polyclonal CD8 + T cells. Furthermore, reconstituted T cells with defined antigen specificity displayed normal cytotoxic function against peptide-loaded targets. Reconstituted CD8 + lymphoblasts had reduced interferon-γ secretion following stimulation in vitro, suggesting restoration of normal immune regulation. Finally, upon viral challenge, mice with >30% engraftment of gene-modified cells exhibited reduction of cytokine hypersecretion and cytopenias. This study demonstrates the potential of hematopoietic stem cell gene therapy as a curative treatment for perforin-deficient FHL

Noves cites i nous hostes d'Andricus sphaericus Pujade-Villar, 2016 (Hymenoptera: Cynipidae)

Andricus sphaericus Pujade-Villar, 2016 és una espècie que va ser coŀlectada per primer cop en 2011 i posteriorment en 2014 sobre Quercus rugosa Née i Q. obtusata Humb. & Bonpl. (secció Quercus, Fagaceae) a l'Estat de México i al DF, i que ha estat recentment descrita (Pujade-Villar et al., 2016). Coŀlectes realitzades pels coautors mexicans en 2015 (entregades al primer autor el juliol d'aquest any) i coŀlectes realitzades aquesta anualitat pel primer autor aporten noves dades d'aquesta espècie, amplien l'ària de distribució i es citen per primer cop gèneres d'inquilins i parasitoids

Una especie nueva de avispa gallícola para México: Andricus sphaericus Pujade-Villar n. sp. (Hymenoptera: Cynipidae: Cynipini)

Se describe una nueva especie de cinípido gallícola de México, Andricus sphaericus Pujade-Villar n. sp., solo conocida por su forma sexual. Induce agallas en las hojas de Quercus rugosa Née. Representa la segunda colecta de una generación sexual del género Andricus para México. Se proporcionan datos referidos a la diagnosis, distribución y biología de esta nueva especie

Thermodynamic simulation of reduction of mixtures of iron ore, siderurgical wastes and coal

The thermodynamic feasibility of reducing agglomerates in iron ore/carbon (ICA) from concentrate mixtures of goethite ore, siderurgical waste and carbon were performed using the HSC Chemistry for Windows V. 6.0 software. Removal by reduction and gasification of Na2O, K2O, ZnO and the metallization of iron oxides was performed by using a reducing atmosphere generated by heating the mixtures. Proposed mixtures generate reductions near 100 % of iron with 28 % of carbon and average removal percentages of 85 % of Na, K and Zn have been obtained

A new genus of oak gall wasp, Striatoandricus Pujade-Villar (Hyenoptera: Cynipidae: Cynipini) from Americ with descriptions of two new Mexican species

A new genus of cynipid oak gall wasp, Striatoandricus Pujade-Villar (Hymenoptera: Cynipidae: Cynipini), is described. Striatoandricus gen. nov. includes four previously described species, Andricus nievesaldreyi n. comb., A. georgei n. comb., A. maesi n. comb., and A. barriosi n. comb., which induce pubescent leaves or twig galls on Quercus belonging to Quercus section. Two new species from México are also described: S. cuixarti Pujade-Villar n. sp. and S. sanchezi Pujade-Villar n. sp. in Quercus section. Descriptions of the genus and diagnostic characters, including DNA sequence data, are presented. This new genus is supported by both morphological and molecular data

Monitoring for COVID-19 by universal testing in a homeless shelter in Germany: a prospective feasibility cohort study

Background: Living conditions in homeless shelters facilitate the transmission of COVID-19. Social determinants and pre-existing health conditions place homeless people at increased risk of severe disease. Described outbreaks in homeless shelters resulted in high proportions of infected residents and staff members. In addition to other infection prevention strategies, regular shelter-wide (universal) testing for COVID-19 may be valuable, depending on the level of community transmission and when resources permit. Methods: This was a prospective feasibility cohort study to evaluate universal testing for COVID-19 at a homeless shelter with 106 beds in Berlin, Germany. Co-researchers were recruited from the shelter staff. A PCR analysis of saliva or self-collected nasal/oral swab was performed weekly over a period of 3 weeks in July 2020. Acceptability and implementation barriers were analyzed by process evaluation using mixed methods including evaluation sheets, focus group discussion and a structured questionnaire. Results: Ninety-three out of 124 (75%) residents were approached to participate in the study. Fifty-one out of the 93 residents (54.8%) gave written informed consent; thus 41.1% (51 out of 124) of all residents were included in the study. Among these, high retention rates (88.9-93.6%) of a weekly respiratory specimen were reached, but repeated collection attempts, as well as assistance were required. Around 48 person-hours were necessary for the sample collection including the preparation of materials. A self-collected nasal/oral swab was considered easier and more hygienic to collect than a saliva specimen. No resident was tested positive by RT-PCR. Language barriers were the main reason for non-participation. Flexibility of sample collection schedules, the use of video and audio materials, and concise written information were the main recommendations of the co-researchers for future implementation. Conclusions: Voluntary universal testing for COVID-19 is feasible in homeless shelters. Universal testing of high-risk facilities will require flexible approaches, considering the level of the community transmission, the available resources, and the local recommendations. Lack of human resources and laboratory capacity may be a major barrier for implementation of universal testing, requiring adapted approaches compared to standard individual testing. Assisted self-collection of specimens and barrier free communication may facilitate implementation in homeless shelters. Program planning must consider homeless people's needs and life situation, and guarantee confidentiality and autonomy