Eyes of the world on a warmer, less frozen, and greener Arctic.

Rapid atmospheric warming and sea-ice retreat are driving widespread changes in Arctic ecosystems, among the most pervasive of which is the "greening of the Arctic"-an increase in the cover and biomass of vegetation observed by satellites across much of the Arctic tundra biome. Determining the drivers, impacts, and feedbacks of Arctic greening requires continued investment in robust field, remote-sensing, and model-based capabilities, and improved integration of the knowledge base of Arctic peoples. These tools and approaches support the triangulation of complex problems and the development of improved projections for the warmer Arctic tundra biome of the future.

Selected Case From the Arkadi M. Rywlin International Pathology Slide Seminar: Atypical Thymoma With Rhabdomyomatous Differentiation.

Thymic epithelial neoplasms with foci of rhabdomyomatous differentiation are rare. A case is presented of a primary thymic epithelial neoplasm showing the features of an atypical spindle cell thymoma that contained foci of bland-appearing rhabdomyomatous cells. The histologic and immunohistochemical features of this tumor are discussed along with a review of the literature and the comments from the AMR members to the case.

Vegetation on mesic loamy and sandy soils along a 1700-km maritime Eurasia Arctic Transect.

QUESTIONS: How do plant communities on zonal loamy vs. sandy soils vary across the full maritime Arctic bioclimate gradient? How are plant communities of these areas related to existing vegetation units of the European Vegetation Classification? What are the main environmental factors controlling transitions of vegetation along the bioclimate gradient? LOCATION: 1700-km Eurasia Arctic Transect (EAT), Yamal Peninsula and Franz Josef Land (FJL), Russia. METHODS: The Braun-Blanquet approach was used to sample mesic loamy and sandy plots on 14 total study sites at six locations, one in each of the five Arctic bioclimate subzones and the forest-tundra transition. Trends in soil factors, cover of plant growth forms (PGFs) and species diversity were examined along the summer warmth index (SWI) gradient and on loamy and sandy soils. Classification and ordination were used to group the plots and to test relationships between vegetation and environmental factors. RESULTS: Clear, mostly non-linear, trends occurred for soil factors, vegetation structure and species diversity along the climate gradient. Cluster analysis revealed seven groups with clear relationships to subzone and soil texture. Clusters at the ends of the bioclimate gradient (forest-tundra and polar desert) had many highly diagnostic taxa, whereas clusters from the Yamal Peninsula had only a few. Axis 1 of a DCA was strongly correlated with latitude and summer warmth; Axis 2 was strongly correlated with soil moisture, percentage sand and landscape age. CONCLUSIONS: Summer temperature and soil texture have clear effects on tundra canopy structure and species composition, with consequences for ecosystem properties. Each layer of the plant canopy has a distinct region of peak abundance along the bioclimate gradient. The major vegetation types are weakly aligned with described classes of the European Vegetation Checklist, indicating a continuous floristic gradient rather than distinct subzone regions. The study provides ground-based vegetation data for satellite-based interpretations of the western maritime Eurasian Arctic, and the first vegetation data from Hayes Island, Franz Josef Land, which is strongly separated geographically and floristically from the rest of the gradient and most susceptible to on-going climate change.

Influence of Sex Ratio and Density on the Comparative Repellency of IR3535® Against Caged Aedes, Anopheles, and Culex Mosquitoes.

Studies on topical repellent efficacy conducted with caged mosquitoes in the laboratory are important to both the development and regulation of insect repellents. Guidelines for laboratory studies stipulate specific densities, sex ratios, and biting rates, whereas those for field studies are governmentally required before a promising repellent can be registered for human use. These protocols stipulate minimum biting rates alone. Relatively little is known, however, about the influence of mosquito density and sex ratio on their biting propensity, either in the field or laboratory. Using Environmental Protection Agency guidelines for cage testing, we studied the influence of mosquito density and sex ratio in laboratory repellency tests of the biopesticide Ethyl butylacetylaminopropionate (IR3535™) (20%) against three mosquito species (Aedes aegypti, Anopheles aquasalis, and Culex quinquefasciatus). DEET [3-(N-acetyl-N-butyl) aminopropionic acid ethyl ester] (20%) in a laboratory prepared formulation was used as a comparison article. Studies were conducted by trained investigators at the BioAgri Laboratories in Brazil. We found that higher mosquito density generally decreased protection time, but that the influence of sex ratio was more complex. The presence of male mosquitoes increased protection times against Aedes and Anopheles perhaps because mate-seeking males interfered with female feeding. Interestingly, by contrast, protection times decreased against Culex in the presence of males. Such considerations may potentially assist in improving the match between cage and field testing under a broader range of conditions that permit more accurate labeling of repellents for safe and effective use by consumers.

Circumpolar arctic tundra biomass and productivity dynamics in response to projected climate change and herbivory.

Satellite remote sensing data have indicated a general 'greening' trend in the arctic tundra biome. However, the observed changes based on remote sensing are the result of multiple environmental drivers, and the effects of individual controls such as warming, herbivory, and other disturbances on changes in vegetation biomass, community structure, and ecosystem function remain unclear. We apply ArcVeg, an arctic tundra vegetation dynamics model, to estimate potential changes in vegetation biomass and net primary production (NPP) at the plant community and functional type levels. ArcVeg is driven by soil nitrogen output from the Terrestrial Ecosystem Model, existing densities of Rangifer populations, and projected summer temperature changes by the NCAR CCSM4.0 general circulation model across the Arctic. We quantified the changes in aboveground biomass and NPP resulting from (i) observed herbivory only; (ii) projected climate change only; and (iii) coupled effects of projected climate change and herbivory. We evaluated model outputs of the absolute and relative differences in biomass and NPP by country, bioclimate subzone, and floristic province. Estimated potential biomass increases resulting from temperature increase only are approximately 5% greater than the biomass modeled due to coupled warming and herbivory. Such potential increases are greater in areas currently occupied by large or dense Rangifer herds such as the Nenets-occupied regions in Russia (27% greater vegetation increase without herbivores). In addition, herbivory modulates shifts in plant community structure caused by warming. Plant functional types such as shrubs and mosses were affected to a greater degree than other functional types by either warming or herbivory or coupled effects of the two.

Vulnerability to forest loss through altered postfire recovery dynamics in a warming climate in the Klamath Mountains.

In the context of ongoing climatic warming, certain landscapes could be near a tipping point where relatively small changes to their fire regimes or their postfire forest recovery dynamics could bring about extensive forest loss, with associated effects on biodiversity and carbon-cycle feedbacks to climate change. Such concerns are particularly valid in the Klamath Region of northern California and southwestern Oregon, where severe fire initially converts montane conifer forests to systems dominated by broadleaf trees and shrubs. Conifers eventually overtop the competing vegetation, but until they do, these systems could be perpetuated by a cycle of reburning. To assess the vulnerability of conifer forests to increased fire activity and altered forest recovery dynamics in a warmer, drier climate, we characterized vegetation dynamics following severe fire in nine fire years over the last three decades across the climatic aridity gradient of montane conifer forests. Postfire conifer recruitment was limited to a narrow window, with 89% of recruitment in the first 4 years, and height growth tended to decrease as the lag between the fire year and the recruitment year increased. Growth reductions at longer lags were more pronounced at drier sites, where conifers comprised a smaller portion of live woody biomass. An interaction between seed-source availability and climatic aridity drove substantial variation in the density of regenerating conifers. With increasing climatic water deficit, higher propagule pressure (i.e., smaller patch sizes for high-severity fire) was needed to support a given conifer seedling density, which implies that projected future increases in aridity could limit postfire regeneration across a growing portion of the landscape. Under a more severe prospective warming scenario, by the end of the century more than half of the area currently capable of supporting montane conifer forest could become subject to minimal conifer regeneration in even moderate-sized (10s of ha) high-severity patches.

Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

Tall shrub and tree expansion in Siberian tundra ecotones since the 1960s.

Circumpolar expansion of tall shrubs and trees into Arctic tundra is widely thought to be occurring as a result of recent climate warming, but little quantitative evidence exists for northern Siberia, which encompasses the world's largest forest-tundra ecotonal belt. We quantified changes in tall shrub and tree canopy cover in 11, widely distributed Siberian ecotonal landscapes by comparing very high-resolution photography from the Cold War-era 'Gambit' and 'Corona' satellite surveillance systems (1965-1969) with modern imagery. We also analyzed within-landscape patterns of vegetation change to evaluate the susceptibility of different landscape components to tall shrub and tree increase. The total cover of tall shrubs and trees increased in nine of 11 ecotones. In northwest Siberia, alder (Alnus) shrubland cover increased 5.3-25.9% in five ecotones. In Taymyr and Yakutia, larch (Larix) cover increased 3.0-6.7% within three ecotones, but declined 16.8% at a fourth ecotone due to thaw of ice-rich permafrost. In Chukotka, the total cover of alder and dwarf pine (Pinus) increased 6.1% within one ecotone and was little changed at a second ecotone. Within most landscapes, shrub and tree increase was linked to specific geomorphic settings, especially those with active disturbance regimes such as permafrost patterned-ground, floodplains, and colluvial hillslopes. Mean summer temperatures increased at most ecotones since the mid-1960s, but rates of shrub and tree canopy cover expansion were not strongly correlated with temperature trends and were better correlated with mean annual precipitation. We conclude that shrub and tree cover is increasing in tundra ecotones across most of northern Siberia, but rates of increase vary widely regionally and at the landscape scale. Our results indicate that extensive changes can occur within decades in moist, shrub-dominated ecotones, as in northwest Siberia, while changes are likely to occur much more slowly in the highly continental, larch-dominated ecotones of central and eastern Siberia.

Plant functional types in Earth system models: past experiences and future directions for application of dynamic vegetation models in high-latitude ecosystems.

BACKGROUND: Earth system models describe the physical, chemical and biological processes that govern our global climate. While it is difficult to single out one component as being more important than another in these sophisticated models, terrestrial vegetation is a critical player in the biogeochemical and biophysical dynamics of the Earth system. There is much debate, however, as to how plant diversity and function should be represented in these models. SCOPE: Plant functional types (PFTs) have been adopted by modellers to represent broad groupings of plant species that share similar characteristics (e.g. growth form) and roles (e.g. photosynthetic pathway) in ecosystem function. In this review, the PFT concept is traced from its origin in the early 1800s to its current use in regional and global dynamic vegetation models (DVMs). Special attention is given to the representation and parameterization of PFTs and to validation and benchmarking of predicted patterns of vegetation distribution in high-latitude ecosystems. These ecosystems are sensitive to changing climate and thus provide a useful test case for model-based simulations of past, current and future distribution of vegetation. CONCLUSIONS: Models that incorporate the PFT concept predict many of the emerging patterns of vegetation change in tundra and boreal forests, given known processes of tree mortality, treeline migration and shrub expansion. However, representation of above- and especially below-ground traits for specific PFTs continues to be problematic. Potential solutions include developing trait databases and replacing fixed parameters for PFTs with formulations based on trait co-variance and empirical trait-environment relationships. Surprisingly, despite being important to land-atmosphere interactions of carbon, water and energy, PFTs such as moss and lichen are largely absent from DVMs. Close collaboration among those involved in modelling with the disciplines of taxonomy, biogeography, ecology and remote sensing will be required if we are to overcome these and other shortcomings.

A protocol for addressing acute pain and prescribing opioids.

Physicians across the country are re-examining their role in the prescription opioid abuse problem. In response to growing public awareness about the dangers of opioids, the Minnesota Medical Association formed a Prescription Opioid Management Advisory Task Force. As part of its work, the task force partnered with the Institute for Clinical Systems Improvement (ICSI) to develop a protocol for prescribing opioids for acute pain. This article describes the development of the new ICSI Acute Pain Assessment and Appropriate Opioid Prescribing Protocol and highlights key aspects of the protocol, which emphasizes shared decision-making and careful, conservative prescribing.

Radiative trigger thresholds of foliar photoprotective pigment regulation for global vegetation.

Adjustments in foliar photoprotective pigments are crucial for plant adaptation to harsh environments, serving as indicators of environmental stress. However, understanding when and where these adjustments occur across diverse biomes remains unclear due to challenges in large-scale observation. Here, we propose a novel approach to assess dynamics in photoprotective pigments at the canopy level using a new index derived from space-borne optical sensors. This approach generates a global map depicting the daily mean shortwave radiation threshold at which adjustments typically occur under prevailing climatic conditions. The global average of this threshold is 262 ± 50 W m⁻2, with lower values at high latitudes and peaks near 40° in both hemispheres. Temperature exerts a stronger influence on this latitudinal pattern than humidity. Future projections suggest a decrease in this threshold over northern high latitudes, implying exacerbated vulnerability under identical radiation levels due to negative warming responses. Based on this threshold, a high-stress zone around 60°N is identified and is predicted to shift southward in the future. These findings bridge critical gaps in photoprotection research and offer a new perspective on understanding the biogeochemical cycles of global ecosystems. This framework can also enhance our ability to predict the fate of diverse ecosystems under future climate.

The Arctic Plant Aboveground Biomass Synthesis Dataset.

Plant biomass is a fundamental ecosystem attribute that is sensitive to rapid climatic changes occurring in the Arctic. Nevertheless, measuring plant biomass in the Arctic is logistically challenging and resource intensive. Lack of accessible field data hinders efforts to understand the amount, composition, distribution, and changes in plant biomass in these northern ecosystems. Here, we present The Arctic plant aboveground biomass synthesis dataset, which includes field measurements of lichen, bryophyte, herb, shrub, and/or tree aboveground biomass (g m-2) on 2,327 sample plots from 636 field sites in seven countries. We created the synthesis dataset by assembling and harmonizing 32 individual datasets. Aboveground biomass was primarily quantified by harvesting sample plots during mid- to late-summer, though tree and often tall shrub biomass were quantified using surveys and allometric models. Each biomass measurement is associated with metadata including sample date, location, method, data source, and other information. This unique dataset can be leveraged to monitor, map, and model plant biomass across the rapidly warming Arctic.

A Second Look at Niacin.

Niacin is the third vitamin to be discovered and, therefore. is known as vitamin B3. It has a long history of medicinal use-nutritionally and as a skin tone brightening agent in skin care. Recent studies have suggested that niacin could be useful as an adjunctive treatment for coronavirus disease 2019 (COVID-19) and mitigating the damaging effect of blue light to the skin. Niacin, also known as nicotinic acid, nicotinamide, and niacinamide, is a physiologically active form of vitamin B3. Medicinal benefits of niacin were observed in 1902, when for the first time, patients with pellagra were treated with yeast that contained vitamin B3. Niacin has a variety of uses, particularly in treating various skin conditions, including topically as an anti-acne treatment, promoting epidermal sphingolipid synthesis, moderating photoimmunosuppression, and reducing hyperpigmentation. Niacinamide could be beneficial as an adjunctive treatment for COVID-19 and for decreasing stress if the skin is excessively exposed to blue light.

Soil and plant-based ecosystem functions dataset of three land-use types in northwestern Virginia.

Variables that quantify nutrient cycling in terrestrial ecosystems, including aboveground and belowground biomass, litter biomass, inorganic nitrogen (NH4 + and NO3 -), and soil CO2 efflux were measured in situ. From measured variables, seasonal litter inputs and nitrogen mineralization were also estimated. Data were collected over the course of one to two growing seasons (2017 and 2018) across three different land-use types under variable human management: an agricultural field (cultivating millet for the duration of the first growing season of the study and left fallow for the duration of the second growing season), a restored native C4 tallgrass prairie, and an approximately 16-year-old successional field. The area of focus within each field was approximately 1 hectare. Five representative 5 m x 5 m plots were randomly chosen in each of the three fields. Within each 5 m x 5 m plot, three 1 m2 subplots were randomly chosen for replicate sampling. These raw data can be utilized to calculate the ecosystem functions of net nitrogen (N) mineralization, decomposition, soil respiration, aboveground primary productivity, and N leaching, which are foundational components of supporting ecosystem services in terrestrial soils and plants. These data can be used in conjunction with other datasets that describe a suite of ecosystem functions in different land-use types under variable management.

Leaf Functional Traits in Relation to Species Composition in an Arctic-Alpine Tundra Grassland.

The relict arctic-alpine tundra provides a natural laboratory to study the potential impacts of climate change and anthropogenic disturbance on tundra vegetation. The Nardus stricta-dominated relict tundra grasslands in the Krkonose Mountains have experienced shifting species dynamics over the past few decades. Changes in species cover of the four competing grasses-Nardus stricta, Calamagrostis villosa, Molinia caerulea, and Deschampsia cespitosa-were successfully detected using orthophotos. Leaf functional traits (anatomy/morphology, element accumulation, leaf pigments, and phenolic compound profiles), were examined in combination with in situ chlorophyll fluorescence in order to shed light on their respective spatial expansions and retreats. Our results suggest a diverse phenolic profile in combination with early leaf expansion and pigment accumulation has aided the expansion of C. villosa, while microhabitats may drive the expansion and decline of D. cespitosa in different areas of the grassland. N. stricta-the dominant species-is retreating, while M. caerulea did not demonstrate significant changes in territory between 2012 and 2018. We propose that the seasonal dynamics of pigment accumulation and canopy formation are important factors when assessing potential "spreader" species and recommend that phenology be taken into account when monitoring grass species using remote sensing.

Paget's disease of the vulva: a clinicopathologic institutional review.

BACKGROUND: The aim of this study was to assess the clinicopathologic characteristics of patients with Paget's disease of the vulva who were treated by our gynecologic oncology service between 1985 and 2010. METHODS: Vulvar Paget's disease patient demographics, pathologic diagnosis, treatment and follow-up data were reviewed over a 25-year period. RESULTS: The vulvar Paget's disease patients were primarily (62.5%) treated with a partial simple vulvectomy. Three patients had a history of malignancy, although none of them was intercurrent. Eleven patients had microscopically positive margins, 5 of whom developed progressive disease. Conversely, 5 patients had negative margins, of whom 4 had recurrent disease. There was a significant relationship between the presence of invasive disease and patient progression-free interval (PFI) (p = 0.007), but margin status and lesion size did not correlate with PFI (p > 0.05). Median patient PFI and follow-up was 30 and 53 months, respectively. CONCLUSIONS: We found a significant relationship between the presence of invasive disease and patient PFI in vulvar Paget's disease although the presence of microscopic positive margins and lesion size were not prognostic indicators. In patients with high risk factors, prolonged surveillance should be considered an essential component of optimal patient management.

Endometrioid adenocarcinoma arising from endometriosis: a case report.

BACKGROUND: Endometriosis is frequently identified in the ovaries, rectum, pelvic peritoneum, cervix and vagina. However, endometriosis undergoing malignant transformation is a rare event, particularly when the condition manifests itself promptly after initial surgical management. CASE: We present a case involving a 52-year-old woman who tested positive for the BRCA1 mutation and was diagnosed with endometriosis in 1999. Two years following treatment, the patient presented with an endometrioid adenocarcinoma; pathologic evaluation indicated that the neoplasm originated from the endometriosis. CONCLUSION: Malignant transformation is a very unusual event and reportedly occurs over several years. Nevertheless, considering the current patient's relatively sudden onset of disease, oncologists should maintain a high index of suspicion in high-risk patients treated surgically for endometriosis who re-present with pelvic symptoms.

Nanotechnology in cosmetic products.

Nanotechnology is a subject of extensive global interest. The ability to control matter at the nanoscale level presents a revolutionary opportunity to benefit society in numerous disciplines. Nanotechnology is currently found in cosmetic products, particularly sunscreen products containing titanium dioxide and zinc oxide. Published information in scientific journals suggests that nano-sized ingredients used in cosmetic products pose no more risk to human health than larger sized counterparts. The issue remains under investigation.

The Impact of Visible Light on Skin.

Visible (VIS) light (400-700 nm), including blue light (400-500 nm), represents approximately 50% of the full optical solar spectrum. It is known since 1938 that visible light penetrates the skin. Biologic markers to fully interpret the significance of such penetration were not utilized at that time to determine the potential damage caused to the skin. The mechanisms of VIS light-induced pigmentation and melanogenesis are currently being investigated by the skin care industry.

Attack on Sunscreens Continues.

The Food and Drug Administration (FDA) was required to issue and put into effect a final sunscreen monograph by November 26, 2019. On March 27, 2020, President Donald Trump signed into effect H.R. 748, the "Coronavirus Aid, Relief, and Economic Security Act" (CARES). This bill eliminated the November 2019 requirement. The CARES Act includes legislative reforms that modernize the way over-the-counter (OTC) monograph drugs are regulated in the United States. Under this Act, sunscreens will be considered generally recognized as safe and effective (GRASE), if they meet conditions newly defined by the FDA. In addition, the FDA is required to issue a proposal to revise the sun-screen requirements for GRASE not later than 18 months after enactment and will sunset by the end of the fiscal year 2022. The CARES Act also addresses the requirement for a new drug application (NDA).1-7.