AISI Standards Update

Since the publication of the 2007 editions, changes and additions have been made to AISI design and construction standards. Accordingly, new editions of the standards, or supplements to existing standards, will be published to formalize these changes. This paper provides an overview of the major changes and additions to those standards

AISI Standards Developed and Updated in 2015 and 2016

During 2015 and 2016, AISI developed framing standards were consolidated and updated, the North American Specification was updated and reorganized in format, and two new test standards were published. This paper provides an overview of the reorganized standards and major changes, and a brief introduction to the newly developed test standards

Overview of Recent Changes and Additions to AISI Standards

Since the publication of the 2007 edit ions of AISI standards, changes and additions have been made to some of the standards. This paper will provide an overview of the majo r revisions to those standards

Psychometric Evaluation of the Transgender Congruence Scale

Introduction Despite increased attention to transgender and gender diverse (TGD) issues in psychological literature during the past decade, gaps remain for psychometric validation of TGD-specific measures. Kozee et al. (Psychology of Women Quarterly 36(2):179–196, 2012) addressed such gaps by creating the Transgender Congruence Scale (TCS), measuring gender acceptance and feelings of gender congruence between internal and external attributes across a broad range of gender identities. The current study extended Kozee and colleagues’ work by further examining the psychometric properties of the TCS. Methods Between October and November of 2017, 210 transmasculine, transfeminine, and gender diverse adults between ages 19 and 73 completed online surveys containing demographic, gender identity-specific, and well-being measures including the TCS. Results Results of confirmatory factor analysis replicated the original two-factor model (Appearance Congruence and Gender Identity Acceptance), with the elimination of two poorly loading items, resulting in a 10-item reduced model (TCS-10). Higher scores on TCS-10 were associated with positive scores on gender-related well-being, congruence, and pride, positive affect, and life satisfaction, as well as lower scores on gender-related dysphoria, non-affirmation, internalized transphobia, and marginalization. There were modest but significant associations between Gender Identity Congruence and both depression and negative affect. Conclusions Despite limitations of sample size and diversity of identities, the study reaffirmed the utility of the TCS as an overall construct of gender identity congruence with a 10-item reduced structure related to other established TGD constructs. Policy Implications Though socio-political climate is the ultimate domain for alleviating TGD stigma and discrimination, factors such as gender congruence are essential areas of focus to foster resiliency

The 2005 World Health Organization Reevaluation of Human and Mammalian Toxic Equivalency Factors for Dioxins and Dioxin-Like Compounds

In June 2005, a World Health Organization (WHO)-International Programme on Chemical Safety expert meeting was held in Geneva during which the toxic equivalency factors (TEFs) for dioxin-like compounds, including some polychlorinated biphenyls (PCBs), were reevaluated. For this reevaluation process, the refined TEF database recently published by Haws et al. (2006, Toxicol. Sci. 89, 4-30) was used as a starting point. Decisions about a TEF value were made based on a combination of unweighted relative effect potency (REP) distributions from this database, expert judgment, and point estimates. Previous TEFs were assigned in increments of 0.01, 0.05, 0.1, etc., but for this reevaluation, it was decided to use half order of magnitude increments on a logarithmic scale of 0.03, 0.1, 0.3, etc. Changes were decided by the expert panel for 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) (TEF = 0.3), 1,2,3,7,8-pentachlorodibenzofuran (PeCDF) (TEF = 0.03), octachlorodibenzo-p-dioxin and octachlorodibenzofuran (TEFs = 0.0003), 3,4,4′,5-tetrachlorbiphenyl (PCB 81) (TEF = 0.0003), 3,3′,4,4′,5,5′-hexachlorobiphenyl (PCB 169) (TEF = 0.03), and a single TEF value (0.00003) for all relevant mono-ortho-substituted PCBs. Additivity, an important prerequisite of the TEF concept was again confirmed by results from recent in vivo mixture studies. Some experimental evidence shows that non-dioxin-like aryl hydrocarbon receptor agonists/antagonists are able to impact the overall toxic potency of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds, and this needs to be investigated further. Certain individual and groups of compounds were identified for possible future inclusion in the TEF concept, including 3,4,4′-TCB (PCB 37), polybrominated dibenzo-p-dioxins and dibenzofurans, mixed polyhalogenated dibenzo-p-dioxins and dibenzofurans, polyhalogenated naphthalenes, and polybrominated biphenyls. Concern was expressed about direct application of the TEF/total toxic equivalency (TEQ) approach to abiotic matrices, such as soil, sediment, etc., for direct application in human risk assessment. This is problematic as the present TEF scheme and TEQ methodology are primarily intended for estimating exposure and risks via oral ingestion (e.g., by dietary intake). A number of future approaches to determine alternative or additional TEFs were also identified. These included the use of a probabilistic methodology to determine TEFs that better describe the associated levels of uncertainty and "systemic” TEFs for blood and adipose tissue and TEQ for body burde

The 2022 world health organization reevaluation of human and mammalian toxic equivalency factors for polychlorinated dioxins, dibenzofurans and biphenyls

In October 2022, the World Health Organization (WHO) convened an expert panel in Lisbon, Portugal in which the 2005 WHO TEFs for chlorinated dioxin-like compounds were reevaluated. In contrast to earlier panels that employed expert judgement and consensus-based assignment of TEF values, the present effort employed an update to the 2006 REP database, a consensus-based weighting scheme, a Bayesian dose response modeling and meta-analysis to derive "Best-Estimate" TEFs. The updated database contains almost double the number of datasets from the earlier version and includes metadata that informs the weighting scheme. The Bayesian analysis of this dataset results in an unbiased quantitative assessment of the congener-specific potencies with uncertainty estimates. The "Best-Estimate" TEF derived from the model was used to assign 2022 WHO-TEFs for almost all congeners and these values were not rounded to half-logs as was done previously. The exception was for the mono-ortho PCBs, for which the panel agreed to retain their 2005 WHO-TEFs due to limited and heterogenous data available for these compounds. Applying these new TEFs to a limited set of dioxin-like chemical concentrations measured in human milk and seafood indicates that the total toxic equivalents will tend to be lower than when using the 2005 TEFs

Plant-symbiotic fungi as chemical engineers: multi-genome analysis of the Clavicipitaceae reveals dynamics of alkaloid Loci

The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some—including the infamous ergot alkaloids—have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne), and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species), a morning-glory symbiont (Periglandula ipomoeae), and a bamboo pathogen (Aciculosporium take), and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories of the epichloae, their protective roles as symbionts, and their associations with the highly speciose and ecologically diverse cool-season grasses

Steel - the Clear Cut Alternative

The current use of cold-formed steel owes its success to efforts which started 50 years ago. In 1946 AISI published the first specification for the design of cold-formed (then known as light gage) steel structural members. The specification was the end product of a doctoral thesis by Dr. George Winter which was initiated in 1939. Since 1946 AISI has continually updated and modernized the AISI Specification for the Design of Cold-Formed Steel Structural Members. The 1956 manual was the first design specification to have a companion commentary. In 1991 AISI published the LRFD version of the Design of Cold-Formed Steel Structural Members. Today AISI is currently developing a single specification which combines the ASD and LRFD design methodologies

Computational Analysis of Thermal Compression Effects in a Supersonic Inlet

The inlet area contraction ratio of a scramjet engine is one of the most important parameters in determining engine performance. A thermal compression inlet is studied in which one surface of an internal-external compression inlet is replaced by a high-pressure jet of combustion gases. The inlet flowfield is calculated using a two-dimensional computer model. The thermal compression inlet is shown to eliminate the boundary layer-shock wave interaction which normally limits inlet contraction ratios of the internal-external compression inlets used at high flight Mach numbers. In addition, studies suggest that the level of compression can be controlled by varying the pressure of the compression jet

Snowmobiling in Utah: An Analysis of Consumer Characteristics, Site Quality, and Carrying Capacity

A consumer characteristic profile of the snowmobile owners in Utah was compiled and compared to the general population in Utah and the United States. Other statistics were compiled which included user preferences of snowmobiling sites and machine characteristics. Data were collected by a mail survey of snowmobilers during the 1974-75 snowmobiling season. Approximately 315 questionnaires were analyzed. Additional data were collected from the Utah Division of Parks and Recreation. Total economic rent values were estimated for 58 sites in Utah. These values were then separated into location and quality values. This was done by reallocating trips to sites by means of a least cost programming technique. The value attributed to location was subtracted from the total and the residual is attributed to site quality. Ten site characteristics were chosen to analyze site quality. Stepwise regression was used to show this relationship. Increasing site carrying capacity was undertaken in the model to show the effect on site quality. An exposition factor for number of trips was derived by using the largest use month, the month with the greatest number of trips recorded. Comparisons were then made between the unexpanded data to that and the expanded data