A WIC Agency Drip Marketing Campaign Is Well Received and Improves Program Participation and Retention: A Quasi-Experimental Study.

BACKGROUND: Little is known about text messaging's influence on child retention in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). OBJECTIVE: This study aimed to evaluate the influence of WICBuzz, a WIC agency drip marketing texting campaign, on retention and participation compared with a comparison WIC agency and to assess WIC participants' perceptions of the campaign's added value. DESIGN: A quasi-experimental design, with pre- and postimplementation measurement, was used to compare innovation and comparison groups' outcomes. Outcome evaluation integrated quantitative analysis of WIC management information system data and survey data of WICBuzz recipients' perceptions. PARTICIPANTS/SETTING: Data obtained for baseline (2019 calendar year) and implementation periods (March 1, 2020, to February 28, 2021), included WIC participation for children who were WIC active at the beginning of each period. WIC agency sample sizes were 6780 to 7452 children from 5189 to 5832 households (baseline) and 4599 to 5004 children from 3186 to 4297 households (implementation). INTERVENTION: WICBuzz, a drip marketing text message campaign with targeted nutrition education and WIC brand awareness messages was the intervention. The comparison agency received standard WIC care. MAIN OUTCOME MEASURES: Main outcome measures included recertification (re-enrollment during the implementation period), timely recertification (within 60 days of prior certification's termination), retention (WIC active at the study period's end), household WIC participation (continuous benefit issuance), and WICBuzz recipients' WIC perceptions. STATISTICAL ANALYSES PERFORMED: Statistical analysis included propensity score weighting and difference-in-difference modeling. Thematic analysis using a deductive approach was used to analyze the process evaluation findings. RESULTS: The influence of WICBuzz on outcomes included 6.7% (95% CI 3.8% to 9.5%) higher recertification, 7.4% (95% CI 4.5% to 10.3%) higher retention, and 10.9% (95% CI 8.0% to 13.8%) higher participation compared with the comparison agency. Most WICBuzz recipients reported added value regarding WIC knowledge and perceptions. CONCLUSIONS: WIC text message campaigns can improve participation and retention and improve participant perceptions of WIC's value.

Ground penetrating radar observations of the contact between the western delta and the crater floor of Jezero crater, Mars.

The delta deposits in Jezero crater contain sedimentary records of potentially habitable conditions on Mars. NASA's Perseverance rover is exploring the Jezero western delta with a suite of instruments that include the RIMFAX ground penetrating radar, which provides continuous subsurface images that probe up to 20 meters below the rover. As Perseverance traversed across the contact between the Jezero crater floor and the delta, RIMFAX detected a distinct discontinuity in the subsurface layer structure. Below the contact boundary are older crater floor units exhibiting discontinuous inclined layering. Above the contact boundary are younger basal delta units exhibiting regular horizontal layering. At one location, there is a clear unconformity between the crater floor and delta layers, which implies that the crater floor experienced a period of erosion before the deposition of the overlying delta strata. The regularity and horizontality of the basal delta sediments observed in the radar cross sections indicate that they were deposited in a low-energy lake environment.

Engagement With and Acceptability of Digital Media Platforms for Use in Improving Health Behaviors Among Vulnerable Families: Systematic Review.

BACKGROUND: The use of digital communication platforms to improve health behaviors has increased dramatically over the last decade. Public health practitioners have adopted digital communication technologies such as text messages, mobile apps, and social media to reach diverse populations. However, the effectiveness of digital communication platforms used by community-serving agencies remains unclear, and patterns of engagement and acceptability of different platforms have not been studied. OBJECTIVE: This review aimed to identify the types of digital communication strategies used by community-serving organizations to promote healthy behaviors, assess the strength of evidence for health behavioral change, and describe the degree of consumer engagement with and acceptability of these strategies. The study population included low-income pregnant women, parents of young children, and adolescents. METHODS: A systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed, Scopus, Web of Science, CINAHL, and APA PsycInfo, covering research conducted from 2009 to 2022. Studies were included if they examined the use of digital communication (ie, texting, mobile apps, or social media) to promote healthy behaviors in the target population. Risk of bias and strength of evidence were assessed using the Effective Public Health Practice Project Risk of Bias tool and criteria from Agency for Healthcare Research and Quality, respectively. RESULTS: Twenty-three peer-reviewed research studies published between 2012 and 2022, conducted in the United States, the United Kingdom, and Australia, were included in the review. The sample comprised studies exploring the use of texting (n=12), apps (n=6), social media (n=3), and multiple platforms (n=2; eg, texting and mobile apps). Targeted health behaviors included healthy diet, physical activity, obesity prevention, healthy pregnancy, breastfeeding, vaccine use, smoking cessation, and nutrition benefit redemption. The sample included 8 randomized controlled trials, 6 pretest-posttest design, 3 mixed methods studies, 2 pilot studies, 1 feasibility study, 1 prospective cohort study, 1 descriptive study, and 1 cross-sectional study. The median sample size was 77.5. There was no strong evidence to suggest the effectiveness of digital media campaigns in improving health behaviors; however, there were moderate to high levels of engagement and high levels of acceptability across digital platforms. CONCLUSIONS: Low-income pregnant women, parents of young children, and adolescents demonstrated moderate levels of engagement with and high levels of acceptability of digital media health campaigns conducted by community-serving agencies. The effectiveness of these strategies in improving health behaviors was inconclusive. Additional rigorous studies with larger sample sizes are required. In addition, more research is required to consistently measure and report participants' engagement with each platform. Digital communication platforms are critical tools for public health practitioners, and future investigations of the effectiveness of these platforms in engaging clients and improving health behaviors will maximize client services.

Ground penetrating radar observations of subsurface structures in the floor of Jezero crater, Mars.

The Radar Imager for Mars Subsurface Experiment instrument has conducted the first rover-mounted ground-penetrating radar survey of the Martian subsurface. A continuous radar image acquired over the Perseverance rover's initial ~3-kilometer traverse reveals electromagnetic properties and bedrock stratigraphy of the Jezero crater floor to depths of ~15 meters below the surface. The radar image reveals the presence of ubiquitous strongly reflecting layered sequences that dip downward at angles of up to 15 degrees from horizontal in directions normal to the curvilinear boundary of and away from the exposed section of the Séitah formation. The observed slopes, thicknesses, and internal morphology of the inclined stratigraphic sections can be interpreted either as magmatic layering formed in a differentiated igneous body or as sedimentary layering commonly formed in aqueous environments on Earth. The discovery of buried structures on the Jezero crater floor is potentially compatible with a history of igneous activity and a history of multiple aqueous episodes.

Primary cutaneous adenoid cystic carcinoma of the scalp: A case report, immunohistochemistry and review of the literature.

Primary cutaneous adenoid cystic carcinoma (PCACC) is an uncommon adnexal skin tumour with fewer than 200 cases studied in detail in the English literature. We describe the diagnosis and treatment of a few Southeast Asian cases of PCACC on the scalp of a 70-year-old Thai female. She presented with a slow-growing, painless, solid to cystic, skin-coloured tumour on her scalp. When excisional biopsy was done, histopathological findings showed dermal tumour that had a classic histologic appearance composed of basaloid cells arranged in a cribriform pattern with 'punched-out' pseudocysts filled with mucin (swiss cheese pattern) and had perineural invasion. The clinical and histopathological findings, and complete investigations confirmed the diagnosis of PCACC. Our case illustrates that PCACC, is an important histopathological differential diagnosis to bear in mind due to its locally aggressive nature and tendency to recur due to perineural invasion. A wide local excision with at least 2 cm of tumour-free margins was performed, which revealed no residual carcinoma. The patient remained disease-free for 16 months after diagnosis. PCACC is usually located on the head or neck of people in their sixth decade of life, with a female predominance. The aetiology of PCACC is unclear. The majority of PCACCs have the MYB-NFIB fusion gene or show overexpression of MYB by immunohistochemistry. Diagnosis of PCACC is primarily based on the characteristic histological appearance, as there are no distinguishing clinical features. The diagnosis of PCACC requires careful exclusion of infiltration or metastasis from other primary lesions. Treatment of this rare tumour is wide surgical excision with at least 2 cm of tumour-free margins to reduce the risk of local recurrence, and long-term follow-up for possible recurrence of PCACC is recommended. This case emphasizes the importance of careful inspection for the diagnosis of PCACC after initial surgery and pathological evaluation of the mass lesion for appropriate diagnosis and therapy.

Role of the Elementary School Cafeteria Environment in Fruit, Vegetable, and Whole-Grain Consumption by 6- to 8-Year-Old Students.

OBJECTIVE: Examine how the physical cafeteria environment contributes to 6- to 8-year-olds' school food consumption. DESIGN: Cross-sectional observational study. Before-and-after lunch tray photos taken with iPads to capture food selection and consumption. SETTING: 10 New York City public elementary school cafeterias. PARTICIPANTS: A total of 382 students aged 6-8 years who ate lunch in the cafeteria on observation days. MAIN OUTCOME MEASURES: Fruit, vegetable, or whole-grain consumption. ANALYSIS: Pearson's chi-square and multivariate logistic regression assessed associations between cafeteria environmental factors (time to eat lunch, noise, and crowding) and vegetable, fruit, and/or whole-grain consumption with 95% confidence, adjusted for school-level demographics and clustered by school. RESULTS: Approximately 70% of students selected fruits, vegetables, and/or whole grains. When selected, consumption was 25%, 43%, and 57%, respectively. Longer time to eat lunch was associated with higher consumption of fruits (odds ratio [OR] = 2.0; 95% confidence interval [CI], 1.1-3.8; P = .02) and whole grains (OR = 2.1; 95% CI, 1.003-4.2; P < .05). Quieter cafeterias were associated with eating more vegetables (OR = 3.9; 95% CI, 1.8-8.4; P < .001) and whole grains (OR = 2.7; 95% CI, 2.6-4.7; P < .001). Less crowding was associated with eating more fruit (OR = 2.3; 95% CI, 1.03-5.3; P = .04) and whole grains (OR = 3.3; 95% CI, 1.9-5.6; P < .001). CONCLUSIONS AND IMPLICATIONS: Healthy food consumption by 6- to 8-year-old students is associated with cafeteria crowding, noise, and time to eat lunch. Implementing and enforcing changes to the cafeteria environment mandated by wellness policies may reduce plate waste.

Cord and Early Childhood Plasma Adiponectin Levels and Autism Risk: A Prospective Birth Cohort Study.

Emerging research suggests that adiponectin, a cytokine produced by adipose tissue, may be implicated in ASD. In this prospective birth cohort study (n = 847), we assessed the association between cord, early childhood plasma adiponectin and the risk of developing ASD. ASD was defined based on ICD codes of physician diagnosis. Cord adiponectin levels were inversely associated with ASD risk (aOR 0.50; 95% CI 0.33, 0.77), independent of preterm birth, early childhood adiponectin and other known ASD risk factors. Early childhood adiponectin, assessed prior to ASD diagnosis, was associated with lower risk of ASD, which attenuated after adjusting for cord adiponectin, indicating the relative importance of cord adiponectin in ASD risk. Further research is warranted to confirm our findings and elucidate biological mechanisms.

B'more Healthy Corner Stores for Moms and Kids: Identifying Optimal Behavioral Economic Strategies to Increase WIC Redemptions in Small Urban Corner Stores.

Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) redemption rates have been declining in many low-income urban settings, potentially related to aspects of the food environment. B'more Healthy Corner Stores for Moms and Kids was a feasibility trial in Baltimore City that aimed to test multiple behavioral economic (BE) strategies in 10 corner stores (intervention = eight stores, comparison = two stores), to evaluate their influence on the stocking and redemptions of WIC foods. Tested strategies included in-person storeowner training, point of purchase promotion, product placement, and grouping of products in a display. All four strategies were feasible and implemented with high reach, dose delivered, and fidelity. Additionally, text messaging was found to be an acceptable form of intervention reinforcement for storeowners. Analyses to assess change in stocking of WIC foods, total sales of WIC foods, and sales of WIC foods to WIC clients, revealed consistent positive changes after implementation of the store owner training strategy, while changes after the implementation of other strategies were mixed. Furthermore, WIC food sales to WIC clients significantly increased after the simultaneous implementation of two strategies, compared to one (p > 0.05). Results suggest that store owner training was the most influential strategy and that the implementation of more BE strategies does not necessarily lead to proportional increases in stocking and sales. Selected BE strategies appear to be an effective way of increasing stocking and sales of WIC foods in small urban food stores.

Fetal and Infancy Growth Pattern, Cord and Early Childhood Plasma Leptin, and Development of Autism Spectrum Disorder in the Boston Birth Cohort.

Leptin is a proinflammatory cytokine that plays an important role in energy homeostasis. Emerging evidence suggests that leptin levels are altered in children with autism spectrum disorder (ASD); however, this has not been studied prospectively. Rapid growth during infancy and early childhood has been implicated in ASD, but the evidence is inconsistent. As leptin is involved in growth and is a potential risk factor for ASD, we explored the associations between (a) cord, early childhood leptin and ASD; and (b) birth weight for gestational age, early childhood weight gain, and ASD. We also assessed the mediating role of leptin in the relationship between weight gain during infancy and ASD. This study was conducted in a sample of 822 subjects from the Boston Birth Cohort. ASD was defined from diagnostic codes in electronic medical records. Extremely rapid weight gain during infancy was associated with a greater ASD risk and this persisted after adjusting for potential confounders (aOR: 3.11; 95% CI: 1.37, 7.07). Similarly, children that had higher plasma leptin levels, prior to ASD diagnosis, had an increased ASD risk in both unadjusted and adjusted models (aOR: 7.87; 95% CI: 2.06, 30.04). Further, early childhood leptin indirectly mediated the relationship between rapid weight gain and ASD. No associations were found between birth weight for gestational age, cord leptin and risk of ASD. Our findings provide a basis to further explore whether the combination of early life growth pattern and a biomarker such as leptin can predict ASD earlier. Autism Res 2018, 11: 1416-1431. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Is early life growth and a biomarker leptin related to ASD risk? To answer this question, we followed 822 children from birth and found that those who gained weight very quickly in infancy, had higher leptin levels in early childhood, had a greater chance of later ASD diagnosis. More research is needed to see if infant's weight gain pattern along with a biomarker (such as leptin) can be used to identify children with ASD sooner.

Integrating Obstetrical Care and WIC Nutritional Services to Address Maternal Obesity and Postpartum Weight Retention.

OBJECTIVE: This pilot study evaluated a cost neutral, integrated Special Supplemental Nutrition Program for Women Infants and Children (WIC) and obstetrical service model designed to prevent postpartum weight retention in obese women. METHODS: A sample of women who received benefits from the Johns Hopkins (JH) WIC program and prenatal care from the JH Nutrition in Pregnancy Clinic, which provides obstetrical care for women with a BMI ≥ 30 kg/m2, participated in the WICNIP randomized clinical trial. Intervention participants received enhanced nutrition services and education at five visits and during one phone call between delivery and 6 months postpartum. Control participants received standard WIC services. Weight data was collected for all participants at multiple time points: pre-pregnancy, delivery, and postpartum at 4, 6 weeks, 4, and 6 months. Maternal socio-demographic factors, obesity class and the number of education contacts received were also recorded. RESULTS: Fifty-three African-American women were randomized into the intervention and control groups. Intervention participants retained significantly less gestational weight gain than control participants (3.0 ± 11.8 vs. 12.6 ± 20.4, p < 0.05). In both groups, participants with Class III obesity retained significantly less weight than participants in Classes I and II (p = 0.02). CONCLUSIONS FOR PRACTICE: An integrated WIC and obstetrical service model is feasible and can limit postpartum weight retention in obese women. Weight retention at 6 months postpartum between intervention and control participants was statistically significant. Further research should explore targeted interventions by obesity class to address weight retention for low-income, African American women who participate in WIC.

Lactase Non-persistence and Lactose Intolerance.

PURPOSE OF REVIEW: To evaluate the clinical and nutritional significance of genetically determined lactase non-persistence and potential lactose and milk intolerance in 65-70% of the world's adult population. RECENT FINDINGS: Milk consumption is decreasing in the USA and is the lowest in countries with a high prevalence of lactase non-persistence. The dairy industry and Minnesota investigators have made efforts to minimize the influence of lactose intolerance on milk consumption. Some lactose intolerant individuals, without co-existent irritable bowel syndrome, are able to consume a glass of milk with a meal with no or minor symptoms. The high frequency of lactase persistence in offspring of Northern European countries and in some nomadic African tribes is due to mutations in the promoter of the lactase gene in association with survival advantage of milk drinking. Educational and commercial efforts to improve calcium and Vitamin D intake have focused on urging consumption of tolerable amounts of milk with a meal, use of lowered lactose-content foods including hard cheeses, yogurt, and lactose-hydrolyzed milk products.

Nondestructive cryomicro-CT imaging enables structural and molecular analysis of human lung tissue.

Micro-computed tomography (CT) enables three-dimensional (3D) imaging of complex soft tissue structures, but current protocols used to achieve this goal preclude cellular and molecular phenotyping of the tissue. Here we describe a radiolucent cryostage that permits micro-CT imaging of unfixed frozen human lung samples at an isotropic voxel size of (11 µm)3 under conditions where the sample is maintained frozen at -30°C during imaging. The cryostage was tested for thermal stability to maintain samples frozen up to 8 h. This report describes the methods used to choose the materials required for cryostage construction and demonstrates that whole genome mRNA integrity and expression are not compromised by exposure to micro-CT radiation and that the tissue can be used for immunohistochemistry. The new cryostage provides a novel method enabling integration of 3D tissue structure with cellular and molecular analysis to facilitate the identification of molecular determinants of disease. NEW & NOTEWORTHY: The described micro-CT cryostage provides a novel way to study the three-dimensional lung structure preserved without the effects of fixatives while enabling subsequent studies of the cellular matrix composition and gene expression. This approach will, for the first time, enable researchers to study structural changes of lung tissues that occur with disease and correlate them with changes in gene or protein signatures.

Evidence for surface water ice in the lunar polar regions using reflectance measurements from the Lunar Orbiter Laser Altimeter and temperature measurements from the Diviner Lunar Radiometer Experiment.

We find that the reflectance of the lunar surface within 5 ° of latitude of the South Pole increases rapidly with decreasing temperature, near ~110K, behavior consistent with the presence of surface water iceThe North polar region does not show this behavior, nor do South polar surfaces at latitudes more than 5° from the pole. This South pole reflectance anomaly persists when analysis is limited to surfaces with slopes less than 10° to eliminate false detection due to the brightening effect of mass wasting, and also when the very bright south polar crater Shackleton is excluded from the analysis. We also find that south polar regions of permanent shadow that have been reported to be generally brighter at 1064 nm do not show anomalous reflectance when their annual maximum surface temperatures are too high to preserve water ice. This distinction is not observed at the North Pole. The reflectance excursion on surfaces with maximum temperatures below 110K is superimposed on a general trend of increasing reflectance with decreasing maximum temperature that is present throughout the polar regions in the north and south; we attribute this trend to a temperature or illumination-dependent space weathering effect (e.g. Hemingway et al. 2015). We also find a sudden increase in reflectance with decreasing temperature superimposed on the general trend at 200K and possibly at 300K. This may indicate the presence of other volatiles such as sulfur or organics. We identified and mapped surfaces with reflectances so high as to be unlikely to be part of an ice-free population. In this south we find a similar distribution found by Hayne et al. 2015 based on UV properties. In the north a cluster of pixels near that pole may represent a limited frost exposure.

A Prospective Birth Cohort Study on Maternal Cholesterol Levels and Offspring Attention Deficit Hyperactivity Disorder: New Insight on Sex Differences.

Growing evidence suggests that maternal cholesterol levels are important in the offspring's brain growth and development. Previous studies on cholesterols and brain functions were mostly in adults. We sought to examine the prospective association between maternal cholesterol levels and the risk of attention deficit hyperactivity disorder (ADHD) in the offspring. We analyzed data from the Boston Birth Cohort, enrolled at birth and followed from birth up to age 15 years. The final analyses included 1479 mother-infant pairs: 303 children with ADHD, and 1176 neurotypical children without clinician-diagnosed neurodevelopmental disorders. The median age of the first diagnosis of ADHD was seven years. The multiple logistic regression results showed that a low maternal high-density lipoprotein level (≤60 mg/dL) was associated with an increased risk of ADHD, compared to a higher maternal high-density lipoprotein level, after adjusting for pertinent covariables. A "J" shaped relationship was observed between triglycerides and ADHD risk. The associations with ADHD for maternal high-density lipoprotein and triglycerides were more pronounced among boys. The findings based on this predominantly urban low-income minority birth cohort raise a new mechanistic perspective for understanding the origins of ADHD and the gender differences and future targets in the prevention of ADHD.

Weight Gain in Infancy and Overweight or Obesity in Childhood across the Gestational Spectrum: a Prospective Birth Cohort Study.

This study aimed to investigate the optimal degree of weight gain across the gestational spectrum in 1971 children enrolled at birth and followed up to age 7 years. Weight gain in infancy was categorized into four groups based on weight gain z-scores: slow (<-0.67), on track (-0.67 to 0.67), rapid (0.67 to 1.28), and extremely rapid (>1.28). Underweight and overweight or obesity (OWO) were defined as a body mass index ≤5(th) and ≥85(th) percentile, respectively, for age and gender. In our population, OWO was far more common than underweight (39.7% vs. 3.6%). Weight gain tracked strongly from age 4 to 24 months, and was positively associated with OWO and an unfavorable pattern of metabolic biomarkers, although the degree of weight gain for the risk was different across gestational categories. Extremely rapid weight gain led to a particularly high risk of OWO among children born early term and late preterm: odds ratio: 3.3 (95% confidence interval: 1.9 to 5.5) and 3.7 (1.8 to 7.5), respectively, as compared to those with on track weight gain. Our findings suggest that monitoring and ensuring optimal weight gain across the entire gestational spectrum beginning from birth represents a first step towards primary prevention of childhood obesity.

Association Between Maternal Prepregnancy Body Mass Index and Plasma Folate Concentrations With Child Metabolic Health.

IMPORTANCE: Previous reports have linked maternal prepregnancy obesity with low folate concentrations and child overweight or obesity (OWO) in separate studies. To our knowledge, the role of maternal folate concentrations, alone or in combination with maternal OWO, in child metabolic health has not been examined in a prospective birth cohort. OBJECTIVE: To test the hypotheses that maternal folate concentrations can significantly affect child metabolic health and that sufficient maternal folate concentrations can mitigate prepregnancy obesity-induced child metabolic risk. DESIGN, SETTING, AND PARTICIPANTS: This prospective birth cohort study was conducted at the Boston Medical Center, Boston, Massachusetts. It included 1517 mother-child dyads recruited at birth from 1998 to 2012 and followed up prospectively up to 9 years from 2003 to 2014. MAIN OUTCOMES AND MEASURES: Child body mass index z score calculated according to US reference data, OWO defined as a body mass index in the 85th percentile or greater for age and sex, and metabolic biomarkers (leptin, insulin, and adiponectin). RESULTS: The mean (SD) age was 28.6 (6.5) years for mothers and 6.2 (2.4) years for the children. An L-shaped association between maternal folate concentrations and child OWO was observed: the risk for OWO was higher among those in the lowest quartile (Q1) as compared with those in Q2 through Q4, with an odds ratio of 1.45 (95% CI, 1.13-1.87). The highest risk for child OWO was found among children of obese mothers with low folate concentrations (odds ratio, 3.05; 95% CI, 1.91-4.86) compared with children of normal-weight mothers with folate concentrations in Q2 through Q4 after accounting for multiple covariables. Among children of obese mothers, their risk for OWO was associated with a 43% reduction (odds ratio, 0.57; 95% CI, 0.34-0.95) if their mothers had folate concentrations in Q2 through Q4 compared with Q1. Similar patterns were observed for child metabolic biomarkers. CONCLUSIONS AND RELEVANCE: In this urban low-income prospective birth cohort, we demonstrated an L-shaped association between maternal plasma folate concentrations and child OWO and the benefit of sufficient folate concentrations, especially among obese mothers. The threshold concentration identified in this study exceeded the clinical definition of folate deficiency, which was primarily based on the hematological effect of folate. Our findings underscore the need to establish optimal rather than minimal folate concentrations for preventing adverse metabolic outcomes in the offspring.

Imaging Mercury's Polar Deposits during MESSENGER's Low-altitude Campaign.

Images obtained during MESSENGER's low-altitude campaign in the final year of the mission provide the highest-spatial-resolution views of Mercury's polar deposits. Images for distinct areas of permanent shadow within 35 north polar craters were successfully captured during the campaign. All of these regions of permanent shadow were found to have low-reflectance surfaces with well-defined boundaries. Additionally, brightness variations across the deposits correlate with variations in the biannual maximum surface temperature across the permanently shadowed regions, supporting the conclusion that multiple volatile organic compounds are contained in Mercury's polar deposits, in addition to water ice. A recent large impact event or ongoing bombardment by micrometeoroids could deliver water as well as many volatile organic compounds to Mercury. Either scenario is consistent with the distinctive reflectance properties and well-defined boundaries of Mercury's polar deposits and the presence of volatiles in all available cold traps.

Formation of lunar swirls by magnetic field standoff of the solar wind.

Lunar swirls are high-albedo markings on the Moon that occur in both mare and highland terrains; their origin remains a point of contention. Here, we use data from the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer to support the hypothesis that the swirls are formed as a result of deflection of the solar wind by local magnetic fields. Thermal infrared data from this instrument display an anomaly in the position of the silicate Christiansen Feature consistent with reduced space weathering. These data also show that swirl regions are not thermophysically anomalous, which strongly constrains their formation mechanism. The results of this study indicate that either solar wind sputtering and implantation are more important than micrometeoroid bombardment in the space-weathering process, or that micrometeoroid bombardment is a necessary but not sufficient process in space weathering, which occurs on airless bodies throughout the solar system.

Compact cold stage for micro-computerized tomography imaging of chilled or frozen samples.

High resolution X-ray microCT (computerized tomography) can be used to image a variety of objects, including temperature-sensitive materials. In cases where the sample must be chilled or frozen to maintain sample integrity, either the microCT machine itself must be placed in a refrigerated chamber, or a relatively expensive commercial cold stage must be purchased. We describe here the design and construction of a low-cost custom cold stage suitable for use in a microCT imaging system. Our device uses a boron nitride sample holder, two-stage Peltier cooler, fan-cooled heat sink, and electronic controller to maintain sample temperatures as low as -25 °C ± 0.2 °C for the duration of a tomography acquisition. The design does not require modification to the microCT machine, and is easily installed and removed. Our custom cold stage represents a cost-effective solution for refrigerating CT samples for imaging, and is especially useful for shared equipment or machines unsuitable for cold room use.