Duality and Serre functor in homotopy categories

For a (right and left) coherent ring $A$, we show that there exists a duality between homotopy categories {\mathbb{K}}^{{\rm{b}}}({\rm mod}{\mbox{-}}A^{{\rm op}}) and {\mathbb{K}}^{{\rm{b}}}({\rm mod}{\mbox{-}}A). If $A=\Lambda$ is an artin algebra of finite global dimension, this duality restricts to a duality between their subcategories of acyclic complexes, {\mathbb{K}}^{{\rm{b}}}_{\rm ac}({\rm mod}{\mbox{-}}\Lambda^{\rm op}) and {\mathbb{K}}^{{\rm{b}}}_{\rm ac}({\rm mod}{\mbox{-}}\Lambda). As a result, it will be shown that, in this case, {\mathbb{K}}_{\rm ac}^{{\rm{b}}}({\rm mod}{\mbox{-}}\Lambda) admits a Serre functor and hence has Auslander-Reiten triangles.Comment: arXiv admin note: text overlap with arXiv:1605.0474

Visualization of clinical teaching citations using social network analysis

Background: Analyzing the previous research literature in the field of clinical teaching has potential to show the trend and future direction of this field. This study aimed to visualize the co-authorship networks and scientific map of research outputs of clinical teaching and medical education by Social Network Analysis (SNA). Methods: We Identified 1229 publications on clinical teaching through a systematic search strategy in the Scopus (Elsevier), Web of Science (Clarivate Analytics) and Medline (NCBI/NLM) through PubMed from the year 1980 to 2018.The Ravar PreMap, Netdraw, UCINet and VOSviewer software were used for data visualization and analysis. Results: Based on the findings of study the network of clinical teaching was weak in term of cohesion and the density in the co-authorship networks of authors (clustering coefficient (CC): 0.749, density: 0.0238) and collaboration of countries (CC: 0.655, density: 0.176). In regard to centrality measures; the most influential authors in the co-authorship network was Rosenbaum ME, from the USA (0.048). More, the USA, the UK, Canada, Australia and the Netherlands have central role in collaboration countries network and has the vertex co-authorship with other that participated in publishing articles in clinical teaching. Analysis of background and affiliation of authors showed that co-authorship between clinical researchers in medicine filed is weak. Nineteen subject clusters were identified in the clinical teaching research network, seven of which were related to the expected competencies of clinical teaching and three related to clinical teaching skills. Conclusions: In order to improve the cohesion of the authorship network of clinical teaching, it is essential to improve research collaboration and co-authorship between new researchers and those who have better closeness or geodisk path with others, especially those with the clinical background. To reach to a dense and powerful topology in the knowledge network of this field encouraging policies to be made for international and national collaboration between clinicians and clinical teaching specialists. In addition, humanitarian and clinical reasoning need to be considered in clinical teaching as of new direction in the field from thematic aspects. © 2021, The Author(s)

Prognostic Role and Clinical Significance of Tumor-Infiltrating Lymphocyte (TIL) and Programmed Death Ligand 1 (PD-L1) Expression in Triple-Negative Breast Cancer (TNBC): A Systematic Review and Meta-Analysis Study

This meta-analysis aimed to evaluate the prognostic value of tumor-infiltrating lymphocytes (TILs) and programmed death-ligand 1 (PD-L1), their associations with the clinicopathological characteristics, and the association between their levels in patients with triple-negative breast cancer (TNBC). PubMed, EMBASE, Scopus, ProQuest, Web of Science, and Cochrane Library databases were searched to obtain the relevant papers. Seven studies with 1152 patients were included in this study. Like the level of TILs, there were no significant associations between PD-L1 expression and tumor size, tumor stage, lymph node metastasis, histological grade, and Ki67 (All p-values ≥ 0.05). Furthermore, there was no significant association between PD-L1 expression with overall survival (OS) and disease-free survival (DFS). In assessment of TILs and survival relationship, the results showed that a high level of TILs was associated with long-term OS (hazard ratios (HR) = 0.48, 95% CI: 0.30 to 0.77, p-value < 0.001) and DFS (HR = 0.53, 95% CI: 0.35 to 0.78, p-value < 0.001). The results displayed that tumoral PD-L1 expression was strongly associated with high levels of TILs in TNBC patients (OR = 8.34, 95% CI: 2.68 to 25.95, p-value < 0.001). In conclusion, the study has shown the prognostic value of TILs and a strong association between tumoral PD-L1 overexpression with TILs in TNBC patients

Validity and Reliability of the Persian Version of the Food Thought Suppression Inventory for Obese University Students

Objectives: To determine the validity and reliability of the Persian version of the Food Thought Suppression Inventory (FTSI) in overweight university students in Iran. Methods: A sample of 233 overweight students were recruited from five universities in Tehran. Participants were asked to complete the Persian versions of FTSI, Binge Eating Scale, Thought Control Questionnaire, Rumination Response Scale, and Dutch Eating Behaviour Questionnaire. Sociodemographic characteristics of participants were also collected. Results: Validity of the Persian version of the FTSI was verified by the fitting indices of the proposed single-factor model of the main makers (Χ2= 112.75, df = 90, p = 0.052, Χ2/df = 1.25, goodness-of-fit index = 0.93, comparative fit index = 0.96, non-normed fitness index = 0.96, root mean score of error approximation = 0.032, and standardised root mean residual = 0.052). Internal consistency of the instrument was high, with a Cronbach's alpha of 0.88. Conclusion: The Persian version of the FTSI is a valid and reliable tool for screening patients in obesity clinics and for evaluating treatment outcomes. © 2020 Hong Kong Academy of Medicine Press. All rights reserved

Large Numbers of Matings Give Female Field Crickets a Direct Benefit but not a Genetic Benefit

Female crickets can potentially gain both direct and indirect benefits from mating multiple times with different males. Most studies have only examined the effects of small numbers of matings, although female crickets are capable of mating many times. The goal of this paper is to examine the direct and indirect benefits of mating large numbers of times for female reproductive success. In a previous experiment, female Gryllus vocalis were found to gain diminishing direct benefits from mating large numbers of times. In this study I attempt to determine whether mating large numbers of times yields similar diminishing returns on female indirect benefits. Virgin female Gryllus vocalis crickets were assigned to mate five, ten or 15 times with either the same or different males. Females that mated more times gained direct benefits in terms of laying more eggs and more fertilized eggs. Females that mated with different males rather than mating repeatedly with the same male did not have higher offspring hatching success, a result that is contrary to other published results comparing female reproductive success with repeated versus different partners. These results suggest that females that mate large numbers of times fail to gain additional genetic benefits from doing so

India and its diaspora: making sense of Hindu identity in South Africa.

Indian immigrants to South Africa in the late nineteenth century differed in terms of their origins, motivations, belief systems, customs, and practices from the indigenous African population as well as from the ruling white settler elite. It is within this context that this paper interrogates some of the ways in which several generations of (Indian) Hindus constructed and continue to (re)construct their religious identities in South Africa. Data for this study were achieved by administering face-to-face questionnaires to 66 individuals in the Metropolitan Area of Durban in KwaZulu-Natal, South Africa. The sample (selected through snowball sampling) comprised third to fifth generation Indians belonging to the four major language groups (Tamil, Telegu, Gujarati, and Hindi) residing in South Africa. Following the questionnaire responses, interviews were conducted with a selected number of respondents from the same sample. Quantitative data were analysed using SPSS while analysis of qualitative data followed a thematic model

Effect of Al2O3 and Cr2O3 on loquidus temperatures in the cristobalite and tridymite primary phase fields of the MgO-"FeO"-SiO2 ststem in equilibrium with metallic iron

The effects of alumina and chromite impurities on the liquidus temperatures in the cristobalite/tridymite (SiO2) primary phase fields in the MgO-FeO-SiO, system in equilibrium with metallic iron have been investigated experimentally. Using high temperature equilibration and quenching followed by electron probe X-ray microanalysis (EPMA), liquiclus isotherms have been determined in the temperatures range 1 673 to 1 898 K. The results are presented in the form of pseudo-ternary sections of the MgO-FeO-SiO, system at 2, 3 and 5 wt% Al2O3, 2 wt% Cr2O3, and 2 wt% Cr2O3+2 wt% Al2O3. The study enables the liquidus to be described for a range of SiO2/MgO and MgO/FeO ratios. It was found that liquiclus temperatures in the cristobalite and tridymite primary phase fields, decrease significantly with the addition of Al2O3 and Cr2O3

The Evolution of a Female Genital Trait Widely Distributed in the Lepidoptera: Comparative Evidence for an Effect of Sexual Coevolution

Sexual coevolution is considered responsible for the evolution of many male genital traits, but its effect on female genital morphology is poorly understood. In many lepidopterans, females become temporarily unreceptive after mating and the length of this refractory period is inversely related to the amount of spermatophore remaining in their genital tracts. Sperm competition can select for males that delay female remating by transferring spermatophores with thick spermatophore envelopes that take more time to be broken. These envelopes could select for signa, sclerotized sharp structures located within the female genital tract, that are used for breaking spermatophores. Thus, this hypothesis predicts that thick spermatophore envelopes and signa evolve in polyandrous species, and that these adaptations are lost when monandry evolves subsequently. Here we test the expected associations between female mating pattern and presence/absence of signa, and review the scant information available on the thickness of spermatophore envelopes.We made a literature review and found information on female mating pattern (monandry/polyandry), presence/absence of signa and phylogenetic position for 37 taxa. We built a phylogenetic supertree for these taxa, mapped both traits on it, and tested for the predicted association by using Pagel's test for correlated evolution. We found that, as predicted by our hypothesis, monandry evolved eight times and in five of them signa were lost; preliminary evidence suggests that at least in two of the three exceptions males imposed monandry on females by means of specially thick spermatophore envelopes. Previously published data on six genera of Papilionidae is in agreement with the predicted associations between mating pattern and the characteristics of spermatophore envelopes and signa.Our results support the hypothesis that signa are a product of sexually antagonistic coevolution with spermatophore envelopes

Dendritic cells from aged subjects contribute to chronic airway inflammation by activating bronchial epithelial cells under steady state

The mechanisms underlying the increased susceptibility of the elderly to respiratory infections are not well understood. The crosstalk between the dendritic cells (DCs) and epithelial cells is essential in maintaining tolerance as well as in generating immunity in the respiratory mucosa. DCs from aged subjects display an enhanced basal level of activation, which can affect the function of epithelial cells. Our results suggest that this is indeed the scenario as exposure of primary bronchial epithelial cells (PBECs) to supernatants from unstimulated DCs of aged subjects resulted in activation of PBECs. The expression of CCL20, CCL26, CXCL10, mucin, and CD54 was significantly increased in the PBECs exposed to aged DC supernatants, but not to young DC supernatants. Furthermore, aged DC supernatants also enhanced the permeability of the PBEC barrier. We also found that DCs from aged subjects spontaneously secreted increased levels of pro-inflammatory mediators, interleukin-6, tumor necrosis factor (TNF)-α, and metalloproteinase A disintegrin family of metalloproteinase 10, which can affect the functions of PBECs. Finally, we demonstrated that TNF-α, present in the supernatant of DCs from aged subjects, was the primary pro-inflammatory mediator that affected PBEC functions. Thus, age-associated alterations in DC–epithelial interactions contribute to chronic airway inflammation in the elderly, increasing their susceptibility to respiratory diseases

Development of a Powder Metallurgical Self Cooling Forging Die with Inner Cavities

Powder metallurgy is known for its high potential for producing near net-shape products. A material utilization of up to 95%, paired with comparably low energy costs, allows powder metallurgy to fulfil the requirements of modern manufacturing processes. By combining different powders, a wide range of products can be manufactured. An innovative powder metallurgical method currently being investigated at the Institute of Forming Technology and Machines (IFUM) within the subproject E3 of the Collaborative Research Centre 653 is the generation of controlled cavities inside a sintered part. For this purpose, a foreign element with a lower melting point than the base powder is embedded inside the green body. Depending on the sintering temperature, the foreign element can be firmly bonded with or melted out of the base powder, creating a defined cavity. Being attached to an external cooling system, the cavity can be applied as a closed circuit for circulating a cooling medium within the tool. The approach in this work is the development of a sintered forging die, equipped with an active temperature regulation which can react autonomously to process variations. The cooling temperature is controlled by measuring the operating temperature within the forging die. For measuring purposes, the cavities can also be used for integrating temperature sensors. The main aspect of these studies is the characterization of the compaction and melting behavior of the foreign material. Since the location of the foreign element within the base powder can differ due to the pressing force, the prediction of its final position based on the initial position and the process conditions is of high importance. For this aim, numerical simulations are employed to develop an optimized cooling layout. A numerical model is used to describe the compaction behaviour of the powder as an elastoplastic compressible continuum and its interdependency with the integrated elements. The studies also cover the influence of surface contours of the foreign elements (corrugated, plain) on their melting behavior as well as the resulting inner surface of the cooling channel