An Early Study on the Mechanisms that Allow Tissue-Engineered Vascular Grafts to Resist Intimal Hyperplasia

Intimal hyperplasia is one of the prominent failure mechanisms for arteriovenous fistulas and arteriovenous access grafts. Human tissue-engineered vascular grafts (TEVGs) were implanted as arteriovenous grafts in a novel baboon model. Ultrasound was used to monitor flow rates and vascular diameters throughout the study. Intimal hyperplasia in the outflow vein of TEVGs was assessed at the anastomosis and at juxta-anastomotic regions via histological analysis, and was compared to intimal hyperplasia with polytetrafluoroethylene (PTFE) grafts in the baboon model and in literature reports from other animal models. Less venous intimal hyperplasia was observed in histological sections with arteriovenous TEVGs than with arteriovenous PTFE grafts. TEVGs were associated with a mild, noninflammatory intimal hyperplasia. The extent of intimal tissue that formed with TEVG placement correlated with the rate of blood flow through tissue engineered vascular grafts at 2 weeks postimplant. Outflow vein dilatation was observed with increased flow rate. Both mid-graft flow rates and outflow vein diameters reached a plateau by week 4, which suggested that venous remodeling and intimal hyperplasia largely occurred within the first 4 weeks of implant in the baboon model. Given their compliant and noninflammatory nature, TEVGs appear resistant to triggers for venous intimal hyperplasia that are common for PTFE arteriovenous grafts, including (1) abundant proinflammatory macrophage populations that are associated with PTFE grafts and (2) compliance mismatch between PTFE grafts and the outflow vein. Our findings suggest that arteriovenous TEVGs develop only a mild form of venous intimal hyperplasia, which results from the typical hemodynamic changes that are associated with arteriovenous settings

Service quality, satisfaction, and behavioral intention in home delivered meals program

This study was conducted to evaluate recipients' perception of service quality, satisfaction, and behavioral intention in home delivered meals program in the US. Out of 398 questionnaires, 265 (66.6%) were collected, and 209 questionnaires (52.5%) were used for the statistical analysis. A Confirmatory Factor Analysis (CFA) with a maximum likelihood was first conducted to estimate the measurement model by verifying the underlying structure of constructs. The level of internal consistency in each construct was acceptable, with Cronbach's alpha estimates ranging from 0.7 to 0.94. All of the composite reliabilities of the constructs were over the cutoff value of 0.50, ensuring adequate internal consistency of multiple items for each construct. As a second step, a Meals-On-Wheels (MOW) recipient perception model was estimated. The model's fit as indicated by these indexes was satisfactory and path coefficients were analyzed. Two paths between (1) volunteer issues and behavioral intention and (2) responsiveness and behavioral intention were not significant. The path for predicting a positive relationship between food quality and satisfaction was supported. The results show that having high food quality may create recipient satisfaction. The findings suggest that food quality and responsiveness are significant predictors of positive satisfaction. Moreover, satisfied recipients have positive behavioral intention toward MOW programs

Stochastic Pharmacokinetic-Pharmacodynamic Modeling for Assessing the Systemic Health Risk of Perfluorooctanoate (PFOA)

A phase 1 dose-escalation trial assessed the chemotherapeutic potential of ammonium perfluorooctanoate (APFO). Forty-nine primarily solid-tumor cancer patients who failed standard therapy received weekly APFO doses (50mg-1200mg) for six-weeks. Clinical chemistries and plasma PFOA (anionic APFO) were measured pre-dose and weekly thereafter. Several clinical measures including total cholesterol, high-density lipoproteins (HDL), thyroid stimulating hormone (TSH), and free thyroxine (fT4), relative to PFOA concentrations, were examined by: standard statistical analyses using general estimating equations (GEE) and a probabilistic analysis using probability distribution functions (pdf) at various PFOA concentrations; and a two-compartment pharmacokinetic/pharmacodynamic (PK/PD) model to directly estimate mean changes. Based on the GEE, the average rates of change in total cholesterol and fT4 associated with increasing PFOA were approximately -1.2x10−3mmol/L/μM and 2.8x10−3pmol/L/μM, respectively. The PK/PD model predicted more closely the trends observed in the data as well as the pdfs of biomarkers. A decline in total cholesterol was observed, with a clear transition in shape and range of the pdfs, manifested by the maximum value of the Kullback-Leibler (KL) divergence, that occurred at plasma PFOA between 420 and 565 μM (175,000–230,000 ng/mL). HDL was unchanged. An increase in fT4 was observed at a higher PFOA transition point, albeit TSH was unchanged. Our findings are consistent with some animal models and may motivate re-examination of the epidemiological studies to PFOA at levels several orders of magnitude lower than this study. These observational studies have reported contrary associations, but currently understood biology does not support the existence of such conflicting effects

Non-escaping frost tolerant QTL linked genetic loci at reproductive stage in six wheat DH populations

Reproductive stage frost poses a major constraint for wheat production in countries such as Australia. However, little progress has been made in identifying key genes to overcome the constraint. In the present study, a severe frost event hit two large-scale field trials consisting of six doubled haploid (DH) wheat populations at reproductive stage (young microspore stage) in Western Australia, leading to the identification of 30 robust frost QTL on 17 chromosomes. The major 18 QTL with the phenotype variation over 9.5% were located on 13 chromosomes including 2A, 2B, 2D, 3A, 4A, 4B, 4D, 5A, 5D, 6D, 7A, 7B and 7D. Most frost QTL were closely linked to the QTL of anthesis, maturity, Zadok stages as well as linked to anthesis related genes. Out of those, six QTL were repetitively detected on the homologous regions on 2B, 4B, 4D, 5A, 5D, 7A in more than two populations. Results showed that the frost damage is associated with alleles of Vrn-A1a, Vrn-D1a, Rht-B1b, Rht-D1b, and the high copy number of Ppd-B1. However, anthesis QTL and anthesis related genes of Vrn-B1a and TaFT3-1B on chromosomes 5B and 1B did not lead to frost damage, indicating that these early-flowering phenotype related genes are compatible with frost tolerance and thus can be utilised in breeding. Our results also indicate that wild-type alleles Rht-B1a and Rht-D1a can be used when breeding for frost-tolerant varieties without delaying flowering time

A Proposed Model

Rocha-Penedo, R., Cruz-Jesus, F., & Oliveira, T. (2021). Opposite Outcomes of Social Media Use: A Proposed Model. In S. K. Sharma, Y. K. Dwivedi, B. Metri, & N. P. Rana (Eds.), Re-imagining Diffusion and Adoption of Information Technology and Systems: A Continuing Conversation - IFIP WG 8.6 International Conference on Transfer and Diffusion of IT, TDIT 2020, Proceedings (pp. 524-537). (IFIP Advances in Information and Communication Technology; Vol. 618). Springer. https://doi.org/10.1007/978-3-030-64861-9_46Social media are probably one of the most influential and disruptive technology of the present times. It is ubiquitous and has the capability to influence virtually every aspect of one’s life while, at the same time, also influence the way firms and public organizations operate and communicate with individuals. Although there is a plethora of studies in the IS literature focused on SM adoption and outcomes, studies hypothesizing positive and negative outcomes together are scarce. We propose a comprehensive research model to shed light on SM positive and negative outcomes, and how these affect one’s happiness. We also explore how personality traits can influence these relationships.authorsversionpublishe

Water quality and its interlinkages with the Sustainable Development Goals

Interlinkages among the Sustainable Development Goals (SDGs) lead to important trade-offs and synergies among the goals and their underlying targets. The aim of this paper is to review the role of water quality as an agent of interlinkages among the SDGs. It was found that there are a small number of explicit interconnections, but many more inferred interlinkages between water quality and various targets. A review of case studies showed that interlinkages operate from the municipal to near global scales, that their importance is likely to increase in developing countries, and that new SDG indicators are needed to monitor them. The analysis identifies many different SDG target areas where a combined effort between the water quality community and other sectors would bring mutual benefits in achieving the water quality and other targets

Constructing ordinary places: Place-making in urban informal settlements in Mexico

Observers from a variety of disciplines agree that informal settlements account for the majority of housing in many cities of the global South. Urban informal settlements, usually defined by certain criteria such as self-build housing, sub-standard services, and residents’ low incomes, are often seen as problematic, due to associations with poverty, irregularity and marginalisation. In particular, despite years of research and policy, gaps in urban theory and limited understandings of urban informal settlements mean that they are often treated as outside ‘normal’ urban considerations, with material effects for residents including discrimination, eviction and displacement. In response to these considerations, this article uses a place-making approach to explore the spatial, social and cultural construction of place in this context, in order to unsettle some of the assumptions underlying discursive constructions of informal settlements, and how these relate to spatial and social marginalisation. Research was carried out using a qualitative, ethnographic methodology in two case study neighbourhoods in Xalapa, Mexico. Mexico offers fertile ground to explore these issues. Despite an extensive land tenure regularisation programme, at least 60 per cent of urban dwellers live in colonias populares, neighbourhoods with informal characteristics. The research found that local discourses reveal complex and ambivalent views of colonias populares, which both reproduce and undermine marginalising tendencies relating to ‘informality’. A focus on residents’ own place-making activities hints at prospects for rethinking urban informal settlements. By capturing the messy, dynamic and contextualised processes that construct urban informal settlements as places, the analytical lens of place-making offers a view of the multiple influences which frame them. Informed by perspectives from critical social geography which seek to capture the ‘ordinary’ nature of cities, this article suggests imagining urban informal settlements differently, in order to re-evaluate their potential contribution to the city as a whole

Legal Pluralism in Theory and Practice

Legal pluralism has vast policy and governance implications. In developing countries, for instance, non-state justice systems often handle most disputes and retain substantial autonomy and authority. Legal pluralism's importance, however, is rarely recognized and dramatically under theorized. This article advances scholarly understanding of legal pluralism both theoretically and empirically. It proposes a new typological framework for conceptualizing legal pluralism through four distinct archetypes – combative, competitive, cooperative, and complementary – to help clarify the range of relationships between state and non-state actors. It posits five main strategies used by domestic and international actors in attempts to influence the relationship between state and non-state justice systems: bridging, harmonization, incorporation, subsidization, and repression. As post-conflict situations are fluid and can feature a wide range of relationships between state and non-state actors, they are particularly instructive for showing how legal pluralism archetypes can be shifted over time. Case studies from Timor-Leste and Afghanistan highlight that selecting an appropriate policy is vital for achieving sustainable positive outcomes. Strategies that rely on large scale spending or even the use of substantial military force in isolation are unlikely to be successful. The most promising approaches are culturally intelligible and constructively engage non-state justice networks of authority and legitimacy to collectively advance the judicial state-building process. While the case studies focus on post-conflict states, the theory presented can help understand and improve efforts to promote the rule of law as well as good governance and development more broadly in all legally pluralist settings

Causes of genome instability: the effect of low dose chemical exposures in modern society.

Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus, genome instability can be defined as an enhanced tendency for the genome to acquire mutations; ranging from changes to the nucleotide sequence to chromosomal gain, rearrangements or loss. This review raises the hypothesis that in addition to known human carcinogens, exposure to low dose of other chemicals present in our modern society could contribute to carcinogenesis by indirectly affecting genome stability. The selected chemicals with their mechanisms of action proposed to indirectly contribute to genome instability are: heavy metals (DNA repair, epigenetic modification, DNA damage signaling, telomere length), acrylamide (DNA repair, chromosome segregation), bisphenol A (epigenetic modification, DNA damage signaling, mitochondrial function, chromosome segregation), benomyl (chromosome segregation), quinones (epigenetic modification) and nano-sized particles (epigenetic pathways, mitochondrial function, chromosome segregation, telomere length). The purpose of this review is to describe the crucial aspects of genome instability, to outline the ways in which environmental chemicals can affect this cancer hallmark and to identify candidate chemicals for further study. The overall aim is to make scientists aware of the increasing need to unravel the underlying mechanisms via which chemicals at low doses can induce genome instability and thus promote carcinogenesis

Summer warming explains widespread but not uniform greening in the Arctic tundra biome

Arctic warming can influence tundra ecosystem function with consequences for climate feedbacks, wildlife and human communities. Yet ecological change across the Arctic tundra biome remains poorly quantified due to field measurement limitations and reliance on coarse-resolution satellite data. Here, we assess decadal changes in Arctic tundra greenness using time series from the 30 m resolution Landsat satellites. From 1985 to 2016 tundra greenness increased (greening) at ~37.3% of sampling sites and decreased (browning) at ~4.7% of sampling sites. Greening occurred most often at warm sampling sites with increased summer air temperature, soil temperature, and soil moisture, while browning occurred most often at cold sampling sites that cooled and dried. Tundra greenness was positively correlated with graminoid, shrub, and ecosystem productivity measured at field sites. Our results support the hypothesis that summer warming stimulated plant productivity across much, but not all, of the Arctic tundra biome during recent decades