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Evaporation or freezing of water-rich fluids with dilute concentrations of dissolved salts can produce brines, as observed in closed basins on Earth1 and detected by remote sensing on icy bodies in the outer Solar System2,3. The mineralogical evolution of these brines is well understood in regard to terrestrial environments4, but poorly constrained for extraterrestrial systems owing to a lack of direct sampling. Here we report the occurrence of salt minerals in samples of the asteroid (101955) Bennu returned by the OSIRIS-REx mission5. These include sodium-bearing phosphates and sodium-rich carbonates, sulfates, chlorides and fluorides formed during evaporation of a late-stage brine that existed early in the history of Bennu's parent body. Discovery of diverse salts would not be possible without mission sample return and careful curation and storage, because these decompose with prolonged exposure to Earth's atmosphere. Similar brines probably still occur in the interior of icy bodies Ceres and Enceladus, as indicated by spectra or measurement of sodium carbonate on the surface or in plumes2,3. Samples from the asteroid (101955) Bennu, returned by the OSIRIS-REx mission, include sodium-bearing phosphates and sodium-rich carbonates, sulfates, chlorides and fluorides formed during evaporation of a late-stage brine. [ABSTRACT FROM AUTHOR]

Apollo 17 core sample 73001/2 was recently made available to researchers for analysis using state‐of‐the‐art techniques in the framework of a modern understanding of lunar surface processes. In this work, we employ transmission electron microscopic analysis to observe the mineralogy, microstructural, and chemical characteristics of space weathering and solar energetic particle (SEP) track distribution in soil grains in the <20 μm size fraction in core sample 73002. The modal mineralogy and stratigraphic space weathered grain abundance suggests that a geologically recent mixing event affected the top 3 cm of 73002. Surface exposure age distributions derived from SEP tracks demonstrate that individual regolith grains rarely reside on the surface for longer than ∼4 million years. The abundance of surface exposed monomineralic fragments with respect to depth correlates well with bulk measurements of space weathered soils using other techniques, such as ferromagnetic resonance. Exposure age distributions suggest the presence of two unique in situ reworking zones spanning the top 8 cm of the core and median exposure ages decrease with increasing depth for both reworking zones, albeit at different rates. These rates were compared to reworking models and suggest a relationship between median exposure age and reworking rate with respect to depth. Applications of modern transmission electron microscopy to core sample 73001/2 have proven useful in understanding lunar regolith evolution both within the context of the Apollo 17 field site and more broadly via in situ reworking. Plain Language Summary: Space weathering is a process by which lunar soils exposed to the interplanetary space environment are chemically, spectrally, and structurally altered. Apollo 17 lunar core sample 73001/2 was recently released into the scientific community under the Apollo Next Generation Sample Analysis (ANGSA) Program. This core is thought to have sampled a lunar landslide at the base of a mountain. This project utilizes up‐to‐date transmission electron microscopy techniques to understand the space weathering and modal mineralogy within the core sample. Results are compared to regolith mixing models to understand the mechanisms and dynamics of soil mixing. We found elevated numbers of iron and titanium rich components within the top 3 cm of the core relative to layers below it. We also found that individual regolith grains rarely reside on the surface for more than a few million years. Grains with the lowest exposure dominate deeper layers, which suggests a high rate of mixing from small and frequent impacts which forces regolith to migrate below the surface. Key Points: Transmission electron microscopy was used to uncover the mineralogy and space weathering features of soil in Apollo 17 core sample 73002Modal mineralogy and the distribution of space weathered grains indicate frequent and recent mixing in the top 3 cm of the lunar regolithIrradiation damage in grains indicates space weathered soil is reworked beneath the surface in less than a few million years [ABSTRACT FROM AUTHOR]

Throughout the history of human spaceflight, spacefarers have experienced and reported the occurrence ofmedical conditions, including various illnesses and injuries. Therefore, future spaceflight missions to the Moon and Mars will require the capabilities necessary for maintaining the health of these new space travelers. Mass, power, and volume available in the space vehicles used for these missions will be severely constrained. The ability to resupply or evacuate to Earth will be limited or non-existent, and ground-based support will no longer be immediate due to communication latencies and blackouts. These vehicle and mission constraints will necessitate healthcare be provided from an efficiently planned medical system. To provide the necessary care, thesemedical systemswill need to include at aminimum, several different types of medical devices, consumable resources, centralized data management, procedural guidance, and decision support technologies. Medical devices needed for diagnosing and treating medical conditions that are expected to occur during future spaceflight missions may include real-time health monitoring, medical imaging capabilities, as well as blood and urine analysis. Novel methods for interacting with onboard patient medical records will be necessary, as will resource tracking. Terrestrial medicine sharesmany of these same needs, therefore a multitude of these required medical capabilities can likely be satisfied by currently available, Commercial-Off-The-Shelf (COTS) devices and methodologies; however, in some cases the unique space environment and increased mission durations will drive the need for modifications or customization of standard technologies and treatment procedures. This article will provide a review of medical devices and technologies that have been considered for inclusion within future spaceflight medical systems. It will also include a discussion about the modifications and customized development that have been performed, as well as descriptions of the technology demonstrations that have been conducted in analog and spaceflight environments. [ABSTRACT FROM AUTHOR]

Sago starch which naturally contains high amount of resistant starch, comes to the attention due to its ability to confer health benefits as functional food i.e., prebiotic. The present work aimed to investigate the effects of sago starch consumption on body weight, satiation, caecum short chain fatty acids body, and hepatic lipid content on diet-induced obese rats for obesity management. A total of 36 male Sprague Dawley rats were fat-induced and divided into the obesity-prone and obesity-resistant groups. Eight percent and sixteen percent resistant starch from sago and Hi-maize260 were incorporated into the standardised feed formulation. Food intake was weighed throughout the intervention period. The caecum sample was subjected to short chain fatty acids analysis using HPLC. Hepatic lipid content was measured using the Folch method. Both dosages of sago starch (8 and 16% SRS) promoted body weight loss with a reduction of food intake, which suggested satiety. No significant differences was observed in the production of lactate, acetate, propionate, and butyrate from the caecum sample. Both dosages of sago starch (8 and 16% SRS) also showed lower hepatic lipid content and visceral adipose tissue than the baseline and control groups. However, 8% sago starch showed the lowest hepatic lipid content in obesity-prone and obesity-resistant groups. Overall results demonstrated that sago starch has the potential as an obesity and overweightness control regime as it promotes satiety, lowers visceral adipose tissue, and reduces hepatic lipid content. Consumers should consider adding sago starch in their daily meals. [ABSTRACT FROM AUTHOR]

Here we present results from pulsed laser irradiation of troilite samples in an effort to simulate space weathering on airless bodies via micrometeorite impacts. We find that the spectral trends observed in directly irradiated samples and samples with a vapor‐deposited coating are different than those found in silicate minerals previously studied. For instance, direct laser irradiation causes our troilite samples to initially brighten, but continued irradiation causes darkening and a decrease in spectral slope. In contrast, our samples with a vapor‐deposited coating show a continuous increase in spectral slope and overall albedo as the deposit thickness increases. Observation using both digital imaging and electron microscopy of our directly irradiated samples leads us to conclude that topography effects likely become important after a relatively high number of laser pulses in our directly irradiated samples, causing the apparent darkening and decrease in spectral slope. Thus, we conclude that the spectral changes observed relevant to space weathering via micrometeorite impacts are an increase in spectral slope and an increase in the albedo of troilite. Future studies will investigate whether these trends are generally representative of other sulfide‐bearing minerals and of weathering trends in other components found in the asteroid regolith. Plain Language Summary: Carbonaceous asteroids are the most common asteroid found in our solar system. While it is generally accepted that the surfaces of these objects are altered over time by impacts via energetic particles, it is not currently understood how this alteration will change the spectral properties of the surface. In this study, we investigated how the spectral reflectance of troilite (FeS), one component that will likely be found on the surface of these types of asteroids, was altered by pulsed laser irradiation, which is used to mimic micrometeorite impacts that are regularly occurring on asteroid surfaces. The main finding in our study that is different from what has been found in previous studies with other relevant minerals, such as silicates, is that the overall reflectance spectrum brightens as the sample is altered. These results, combined with previous ones, will help astronomers interpret reflectance spectra taken of carbonaceous asteroids and possibly other extraterrestrial objects containing troilite. Key Points: Spectral changes observed in directly irradiated FeS samples and those with a vapor‐deposited coating are differentDirect laser irradiation induces topography effects, which can alter the reflectance spectrum of FeSSpectral changes induced in FeS that are relevant to space weathering are an increase in the albedo and increase in spectral slope [ABSTRACT FROM AUTHOR]

Provides information on a study that examined the surface topography of homoepitaxial diamond films grown by hot-filament chemical vapor deposition on (100)-, (110)- and (111)-oriented natural diamond single-crystal substrates by atomic force microscopy. Methodology of the study; Results and discussion on the study.

Treatment protocols, treatment planning methods and tumour types in studies evaluating radiotherapy for canine brain tumours have been varied. This case series retrospectively evaluated the outcome of definitive, three-dimensional conformal radiation therapy ( 3D-CRT) as either a sole modality or as an adjuvant to surgery in 31 dogs diagnosed with meningioma by histopathology ( n = 10) or cross-sectional imaging of the head ( n = 21, assessed independently by two board certified radiologists). Prescribed dose ranged from 45 to 54 Gy in 2.5 to 3 Gy fractions. Median overall survival was 577 days (interquartile range = 272-829 days; range = 30-1942 days) when all deaths were considered and 906 days (interquartile range = 336-912 days; range = 101-1942 days) when only dogs dying due to meningioma were considered. No significant difference in survival time was detected for the defined clinical or imaging findings or between treatment with radiotherapy alone versus adjuvant radiotherapy, suggesting that 3D-CRT may be a viable alternative to surgery. [ABSTRACT FROM AUTHOR]

Subarctic peatlands are rich sources of organic carbon for freshwater ecosystems. Where those peatlands are underlain by permafrost, permafrost thaw may cause an initial release of bioavailable dissolved organic carbon (DOC) to surrounding freshwaters. In this study, we measured icebound and potentially leachable (extracted) DOC quantities and indices of DOC quality in active layer and permafrost layers from two subarctic peat mires, Stordalen and Storflaket. Most of the permafrost layers did not contain more organic matter or exportable DOC (as g kg-1 dry soil) than the overlying active layer, and there was no difference in aromaticity, molecular weight, or the ratio between labile and recalcitrant DOC extracted from the permafrost and active layer. However, DOC held in segregated ice of the near-surface permafrost had relatively low aromaticity compared to extracted DOC from the same depth. Total icebound and potentially leachable DOC in the Stordalen mire permafrost that is predicted to experience active layer deepening during each of the next 50 years corresponded to about 0.1% of the current annual aquatic export of DOC from the mire. We conclude that the pool of potentially leachable DOC currently stored in permafrost layers is small. We also highlight differences in permafrost organic material between the two studied mire systems, which has an effect on the pool and properties of leachable DOC that is potentially available for export during thaw. Moreover, the geomorphological form of permafrost thaw will influence future hydrological connectedness and DOC production, in turn determining future DOC export from the mires. [ABSTRACT FROM AUTHOR]

Introduction: Space weathering processes alter the microstructural, compositional, and optical properties of airless planetary surfaces. Solar wind space weathering forms ion-damaged rims within the outermost ~100 nm of regolith grains through atomic-displacements and implantation of energetic H+ and He+ ions [1]. Transmission electron microscope (TEM) studies of space weathered Itokawa and lunar olivine particles reveal predominantly nanocrystalline solar wind-damaged rims with only minor regions of amorphization [2-5]. This finding differs from laboratory ion irradiation experiments in which samples become amorphous at fluences 2-3 orders of magnitude lower than the independently constrained fluences for still-crystalline natural samples [6-7]. Ion flux is generally considered to have a secondary effect compared to fluence in these irradiation experiments. However, solar wind irradiation of natural samples occurs at a flux that is ~4-5 orders of magnitude lower than what is used in laboratory simulations (e.g., [6,8-9]). Constraining how the very low ion flux of solar wind influences the microstructural, chemical, and spectral alteration of silicate minerals will improve our understanding of solar wind space weathering and aid in the analysis of returned samples from the Hayabusa2 and OSIRIS-REx missions. Here we report results from low- and high-flux ion irradiation experiments on the Murchison (CM2) meteorite with comparable total fluences. Methods: We performed low-flux and high-flux He+ (4 keV) and H+ (1 keV) irradiation experiments on separate, dry-cut Murchison slabs. Low-flux He+ irradiation reached a total fluence of 2.1 x 1016 ions/cm² (~400 years of exposure at Bennu) using a flux of 3.6 x 1011 ions/cm²/s; low-flux H+ irradiation reached a total fluence of 3.9 x 1016 ions/cm2 (~30 years) using a flux of 6.6 x 1011 ions/cm²/s. High-flux He+ irradiation reached a total fluence of 2.0 x 1016 ions/cm2 (~400 years) using a flux of 9.1 x 1012 ions/cm²/s; high-flux H+ irradiation reached a total fluence of 5.8 x 1016 ions/cm2 (~50 years) using flux of 8.4 x 1012 ions/cm²/s. By irradiating to similar total fluences in both the lowflux and high-flux experiments, we can better isolate and evaluate the effects of ion flux. Differences between unirradiated and irradiated surfaces are determined using three analytical techniques: (1) in situ X-ray photoelectron spectroscopy (XPS) reveals changes in surface chemistry, (2) visible to near-infrared spectroscopy (VNIR; 0.35-2.5 µm) highlights changes in spectral trends, such as albedo and slope, and (3) TEM and energy-dispersive X-ray spectroscopy (EDS) identifies changes in nanoscale structure and elemental composition within olivine and matrix electron-transparent thin sections prepared using focused ion beam scanning electron microscopy (FIB-SEM). Results and Discussion: XPS analyses of the low-flux and high-flux He+- and H+-irradiated samples show a minor reduction in surface carbon content and chemical reduction of Fe3+ to Fe2+. The latter result is consistent with the higher Fe2+/Fe3+ ratios observed in phyllosilicate-rich space weathered rims of Ryugu grains [10]. VNIR analyses suggest that the low-flux H+-irradiated spectrum has a slightly bluer slope (over 0.65-2.5 µm) compared to the unirradiated VNIR spectrum from [9] while the low-flux He+-irradiated spectral slope is comparable to the unirradiated surface. Both the high-flux He+- and H+-irradiated VNIR spectra exhibit slightly higher albedos at shorter wavelengths relative to their unirradiated counterparts, with He+ irradiation yielding a greater change. Thus far, the low-flux He+-irradiated matrix and olivine FIB sections as well as the low-flux H+-irradiated olivine FIB section have been examined with TEM. The surfaces of all three samples show less vesiculation than high-flux/high-fluence irradiated matrix and olivine samples from [9]. The depth of phyllosilicate amorphization in the low-flux He+- irradiated matrix FIB section varies laterally, with crystalline domains occurring as shallow as ~25 nm in some regions. The low-flux He+-irradiated olivine FIB section has a continuous, ~40-90 nm thick ion-affected layer with polycrystalline and amorphous microstructures. The low-flux H+-irradiated olivine sample exhibits a distinct, ~10-40 nm ion-affected layer whose uppermost ~20 nm in thicker regions is predominantly amorphous. Continuing to compare results from this work to those from [9] will provide a comprehensive understanding of how ion flux impacts the microstructural, chemical, and optical modification of various mineral phases and, in turn, help identify space weathering features from parent body alteration in Hayabusa2 and OSIRIS-REx returned samples. [ABSTRACT FROM AUTHOR]

Introduction: Space weathering causes the surface regolith on airless bodies like the Moon to be morphologically, microstructurally, and chemically altered due to micrometeoroid bombardment and solar wind irradiation [1]. These processes produce a multitude of microstructural and chemical changes in individual soil grains that accumulate as grains are exposed on the surface over time. One microstructural feature produced by exposure to the solar wind is the development of ion-damaged rims on regolith grains via H+ and He+ ion irradiation. Also present are solar energetic particle (SEP) tracks, which are nanoscale lineations of ionization damage within grain interiors formed by high energy solar flare ions (primarily Fe group nuclei) which penetrate millimeters below the surface [2]. Recent work has confirmed that the thickness of solar wind-damaged amorphous rims on anorthite grains, nanocrystalline rims on olivine grains, and their respective SEP track densities are correlated with their surface exposure ages [3]. Core sample 73002, recently released under the Apollo Next Generation Sample Analysis (ANGSA) Program, has provided an opportunity to study material collected from the light mantle formation during Apollo 17. The light mantle is thought to have been deposited via a landslide originating from the neighboring South Massif [4]. Spectral profiles and ferromagnetic resonance measurements of bulk soils sampled at cm-intervals from 73002 indicate the existence of mature regolith extending ~8 cm below the surface, suggesting the presence of an in-situ reworking zone in the core [5,6]. Here we present the distribution of SEP track densities, solar wind damaged rim widths, and the corresponding surface exposure ages of grains residing in the proposed in-situ reworking zone of core 73002. Methods: Bulk samples of regolith from the first eight intervals and every following fourth interval down the core (dissection Pass 2) were delivered to Purdue University as <45 µm size fractions. The first eight 0.5 cm intervals, representing the top 4 cm of regolith, were individually dry sieved to a <20 µm size fraction, and grains were prepared by ultramicrotomy for analysis in the scanning transmission electron microscope (STEM). Bright field (BF) and dark field (DF) STEM images of solar flare tracks and solar wind damaged rims were acquired on a JEOL 2500SE TEM, equipped with a 60 mm² ultra-thin window silicon drift energy dispersive X-ray (EDX) spectrometer at NASA Johnson Space Center. Grain compositions were determined by EDX compositional spectrum imaging. SEP track densities and amorphous rim thicknesses were measured on BF and DF images. Results: The fraction of grains with discernable space weathering features decreased with depth, with 100% in the first interval exhibiting space weathering features as opposed to ~60% in Interval 8. BF and DF STEM images show splash-melt and vapor deposited rims on outermost grain margins with embedded Fe-bearing nanoparticles ranging in size up to ~10 nm in diameter. Images also show solar-wind damaged rims below the vapor deposits, and SEP tracks present in grain interiors. The rim thicknesses and SEP track densities were determined using the methods of [3] for 54 grains spanning the top 4 cm. ~80% of the grains analyzed were anorthite and ~20% were olivine. The track production rate from [3] was used to estimate the surface exposure times of the grains in this study. The majority of exposure times are in the 1 - 5 MY range for all intervals. The lowest value was 3.8 x 10-5 years in Interval 8 and the highest value was 1.1 x 107 years in Interval 6. Grains with the highest solar wind damage rim thicknesses and SEP track densities are found in Interval 6. The highest rim thickness and track density observed for anorthite is 126.5 nm and 4.7 x 1011 tracks/cm², while for olivine they are 98.6 nm and 1.83 x 1011 tracks/cm², respectively. Discussion: Intervals from the top 4 cm of 73002 show similar SEP track density and solar wind damaged rim thickness distributions. Spectral and ferromagnetic resonance measurements of 73002 indicate an in-situ reworking zone up to ~8 cm below the surface [5,6]. The depth analyzed in this work is within the core's uppermost in-situ reworking zone and may serve as an explanation to the homogenous distribution of exposure ages. The decreasing abundance of space weathered features with depth is consistent with regolith mixing models showing an exponential decay in regolith maturity with depth over time [7]. A maximum surface exposure age determined via SEP track density is approximately 10 million years. This timescale is consistent with the lower estimate of surface exposure ages of the light mantle determined in previous studies, which can range from 10s to over 100 Ma [4]. It also falls within the core regolith reworking development timescale of ~17 Ma [5,6]. Additional analysis will be performed for a further seven intervals in 73002. [ABSTRACT FROM AUTHOR]

Introduction: Remote sensing observations [1,2], laboratory experiments [3,4], and computational simulations [5] each predict that OH/H2O (hereafter water) can form in nominally anhydrous minerals on airless bodies due to space weathering. Space weathering is driven by solar wind irradiation and micrometeoroid bombardment and both mechanisms can change the optical, chemical, and microstructural properties of grains on airless surfaces [6]. Microstructural space weathering features include amorphous rims (upper ~100 nm), reduced and/or oxidized nanophase iron (npFe) particles, and vesicles that may form from the coalescence of solar wind implanted H and He [7]. Solar wind H+ ions can combine with O to form water species in surface minerals. Electron energy loss spectroscopy (EELS) has previously been used to identify such hydrogen and water species in the rims and vesicles of space weathered interplanetary dust particles and lunar regolith grains [8,9]. Atom probe tomography (APT) has also been used to identify hydrogen and water in the rims and vesicles of space weathered olivine from Itokawa [10] and lunar regolith grains [11,12,9]. However, understanding the abundance of hydrogen and water species in space weathered lunar grains and their relationship with microstructural space weathering features and mineralogy is still at an early stage. Here, we present results of coordinated EELS and APT analyses to understand the distribution of hydrogen and water in relation to microstructural space weathering features and mineralogy. Methods: In this work we analyzed grains from mature lunar mare soil 79221. Individual grains were transferred to an aluminum stub coated in carbon tape and subsequently sputter coated with Pt. We used scanning electron microscopy (SEM) to identify grains 100-200 µm in diameter that displayed vesicles or bubbles on their surface as evidence of solar wind irradiation. An agglutinate particle, clinopyroxene, olivine, plagioclase, and ilmenite grains were identified using energy dispersive x-ray spectroscopy (EDS). We then prepared electron transparent focused ion beam (FIB) cross sections of each grain with the Helios G4 UX Dual Beam FIB-SEM at Purdue University for analysis in the transmission electron microscope (TEM). Adjacent FIB sections were also collected from each grain to produce nanotips sharpened to have an apex radius of ~30 nm for APT analyses. High-resolution TEM (HRTEM) and high-angle annular dark field (HAADF) images were collected to characterize the microstructural space weathering features for FIB sections from each grain using the Thermo Scientific Themis Z monochromated and aberration-corrected TEM equipped with a Gatan Quantum 965 EELS detector at Purdue. Low-loss EELS spectra were collected as linescans across individual vesicles and within the amorphous rims of these grains to identify the presence of hydrogen and water via the hydrogen core scattering edge (H-K), energy gap of water (EG), and ionizing threshold of water (IT) features in the low-loss energy region. APT analyses were performed on tips made from each sample using the CAMECA LEAP 5000XS tomograph at Northwestern University. 3-D reconstructions of elemental information of each tip were analyzed and the presence of H, OH, and H2O were identified based on their mass-to-charge ratios. We then created depth profiles of each of these species to identify their change in concentration with depth. Results and Discussion: EELS analyses of an agglutinate grain revealed the presence of the H-K, IT, and EG features in both the space weathered rim and vesicles indicating the presence of hydrogen and water. APT analyses also identified the presence of H, OH, and H2O in the agglutinate grain and an olivine grain. Depth profiles in both grains reveal an enrichment in all three species in the space weathered rims which exhibit a steady decrease in concentration with depth into the grain. These profiles are similar in shape to the space weathered Itokawa olivine from [11] but differ from the observed shape in immature lunar ilmenite from [12]. The presence of H, OH, and H2O in vesicles and in space weathered rims provides evidence that solar wind implantation is a viable mechanism to form water on the lunar surface. Further EELS and APT measurements to characterize the relationship between water and microstructural features and comparisons in concentration profiles and abundance across mineralogy are ongoing. [ABSTRACT FROM AUTHOR]

Introduction: Space weathering refers to the chemical, microstructural, and optical changes on the surfaces of airless planetary bodies caused by high-velocity micrometeoroid impacts and solar wind irradiation [1]. Space weathering may alter the spectral properties of airless surfaces by changing the spectral slope, darkening/brightening, and attenuating absorption bands in the visible and near-infrared. These spectral changes make it difficult to establish a link between meteorites and their parent bodies [2], and accurately characterize the mineralogical composition of these surfaces via remote sensing spectroscopy. Analyses of returned regolith samples and laboratory experiments simulating space weathering processes have concentrated on studying silicate minerals, the most abundant phases in lunar soils and ordinary chondrites. However, little is known about the space weathering of magnetite, which is an important mineral phase in carbonaceous chondrites [3], and that has been identified in returned samples from asteroid Ryugu [4,5,6,7,8], and on the surface of asteroid Bennu through remote sensing observations [9]. To better understand the response of magnetite under space weathering conditions, we simulated micrometeoroid bombardment and solar wind irradiation using pulsed laser and ion irradiation experiments, respectively. Methods: We used synthetic magnetite powders with grain sizes <45 µm that were pressed into pellets at 1500 psi. To reproduce micrometeoroid bombardment on the magnetite pellets, we used pulsed-laser irradiation, employing an Nd-YAG laser with 3.5 mJ per pulse and pulse durations of 4-6 ns. To simulate solar wind irradiation, we performed 1 keV H+ and 4 keV He+ irradiation experiments using fluxes ~1 x 1013 ions/cm2/s and total fluences of 8.7x1017 H+/cm2 and 3.6 × 1016 He+/cm2, equivalent to exposure times of ~750 years at 1 AU at the surface of asteroid Bennu, respectively. In addition, we conducted reflectance spectroscopy measurements in the visible near-infrared region (0.3-2.5 µm) for the laser and ion irradiated pellets. We analyzed the microstructural and chemical properties of individual magnetite grains after pulsed-laser and ion irradiation using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Results and Conclusions: TEM analysis of the pulsed laser irradiated sample reveals the presence of a discontinuous crystalline rim in the outermost part of the magnetite grain with a thickness that varies from 5-15 nm. EDS observations show that this rim is enriched in Fe around 5 at% compared to the unaltered region. The 1 keV H+ irradiated sample exhibits a crystalline rim in the outer 35 nm in the grain enriched ~20 at% in Fe compared to the unirradiated surface. However, we identified an increase of O in the outer 15 nm of the rim likely caused by atmospheric oxidation after the irradiation experiments. The 4 keV He+ irradiated magnetite presents elongated structural defects in the upper 50 nm but no changes in the concentration of O and Fe were identified via EDS. No amorphization was observed in the pulsed laser or ion irradiated samples. Reflectance spectroscopy reveals that the 4 keV He+ irradiated sample is darker than an unirradiated pellet used as a reference, whereas the pulsed laser irradiated magnetite is brighter. However, the most significant change is observed in the 1 keV H+ irradiated sample, which is brighter than the unirradiated pellet in the visible wavelengths, reaching up to 2x the reflectance values of the unirradiated sample at the ~470-570 nm region. These results suggest that under space weathering, the concentrations of O and Fe in magnetite rims are altered along with its reflectance and spectral slope. Preliminary analysis of Ryugu regolith particles show the presence of a layer rich in metallic iron nanoparticles (npFe0) on the surface of a magnetite grain [6], which is consistent with the depletion of O that is observed in our experiments. This loss of O could create a reducing environment for the Fe present in magnetite and promote the development of a metallic iron-rich layer. We expect a similar chemical behavior (depletion of O and enrichment of Fe) on magnetite grains that will be returned from asteroid Bennu. Additionally, the resistance of magnetite to amorphization has been also observed in sulfide minerals from asteroid Itokawa, suggesting that Fe-oxides and sulfide phases are more resistant to solar wind irradiation damage compared to silicate minerals. [ABSTRACT FROM AUTHOR]

Introduction and Methods: The alteration of the outer surfaces of grains on airless bodies by space weathering processes results in the production of new nanoscale features. Samples that have been exposed to this environment for a long time are termed mature. Apollo 17 sample Soil 79221 is classified as mature and has previously been used to study space weathering on the Moon, e.g. [1], and herein we present atom-probe tomography (APT) analyses of this soil to compare with our previously published data on submature soil 71501 [2]. In APT, atoms on a sample nanotip are field evaporated using a pulsed picosecond laser and their mass-to-charge-state ratio is measured via a positionsensitive detector, permitting a 3D reconstruction of the outermost ~100s of nanometers of space weathered material, e.g., [2,3]. Lift-outs were performed with a TESCAN LYRA3 FIB-SEM the University of Chicago close to the location of lamellae extracted for TEM for correlative analyses [4]. Prepared nanotips were analyzed with the CAMECA LEAP 5000XS tomograph at Northwestern University. Results: A total of 16 nanotips from agglutinate, plagioclase, olivine, and ilmenite were analyzed for their space weathering features, with nine providing useful data. Of particular interest are the olivine (Fig. 1) and ilmenite nanotips, as they exhibit zones of decreased atomic density which we interpret as vesicles and irregularly shaped defects. These features are prominent in our samples, and are also observed in TEM analyses [5]. The agglutinate nanotips are instead dominated by Fe-rich structures, including whisps of increased oxidation and a microphase Fe particle which are depleted in H relative to the rest of the sample [4]. The ilmenite nanotips contained some nanophase Fe particles, but heterogeneous Fe structures were not observed in the (Mg-rich) olivine nanotips. None of the analyzed samples preserved or included redeposition rims. Discussion: The olivine displays evidence of a complex structure of voids (Fig. 1). There is a fine-scale network of spaces that are much smaller than that of the round vesicles detected in the ilmenite nanotips. Like the vesicles, these void spaces are are filled with H species. Our previous APT study [2] identified a vesicle in submature lunar ilmenite with a small amount of 4He detected. This previously analyzed vesicle was similar in size to one of the vesicles we found in the mature lunar ilmenite, which also included a small 4He signal (5±2 atoms, 1s). Both analyses are missing at least three orders of magnitude of He atoms when compared to data from bulk analyses [6]. A burst of H detections at the top of vesicles indicates the opening and degassing of vesicles as the top of the nanotip field-evaporated during analysis. This suggests that the volatiles in the vesicle largely escaped into the vacuum without being analyzed, with only a small fraction ionized and detected. The number density of vesicles is much greater in the nanotips from the mature soils than the submature soil sample. Where the vesicle comprised a significant volume of the nanotip, the nanotips fractured before an analysis reached the lower half of the vesicle. Vesiculated textures present challenges to APT analysis. Interior voids cannot be filled with coating methods. The resulting non-hemispherical topography from vesicles alters the local electric field-evaporation dynamics in ways that can lead to instabilities and nanotip failure. Mature space-weathered samples are more challenging for APT than submature ones. [ABSTRACT FROM AUTHOR]

Introduction: Space weathering, driven by solar wind irradiation and micrometeoroid bombardment, alters the morphological, microstructural, chemical, and spectral characteristics of grains on the surfaces of airless bodies [1,2]. Our model for space weathering is built in the framework of silicate minerals, which comprise the majority of our returned sample collection from the Moon. Space weathering characteristics identified in lunar silicates include amorphous rims, chemically heterogeneous melt and vapor deposits, vesiculated textures, and nanophase Fe (npFe) particles, e.g., [3]. However, remote sensing observations of asteroids (e.g., Eros) [4], which can be more mineralogically complex than the Moon, and analyses of returned samples from diverse parent bodies (e.g., Itokawa, Ryugu) [5,6] have revealed that sulfide minerals play a critical role in the evolution of asteroidal surfaces. For example, remote X-ray fluorescence observations of Eros revealed surface S-depletion, and the analysis of samples returned by the JAXA Hayabusa and Hayabusa2 missions showed npFeS and npFeNiS particles in grain rims, suggesting that S plays an active role in the development of space weathering characteristics on asteroids. Analysis of these returned samples has also revealed the presence of morphologically unique S-depleted Fe-whiskers on sulfide grain surfaces, e.g., [7,8]. Several formation mechnisms have been proposed for these microstructures, including as a decomposition product from sustained solar wind H+ irradiation [7,8]. To understand the origin of space weathering characteristics unique to sulfide minerals, here we report results of in situ heating of pentlandite and pyrrhotite grains to simulate micrometeoroid bombardment inside the transmission electron microscope (TEM). Methods: We suspended grains of pentlandite and pyrrhotite in isopropanol and dropcast samples onto microelectromechanical systems (MEMS) chips with supporting SiN films (Norcada) for in situ heating using the Hitachi Blaze heating holder under vacuum in the 200 keV aberration-corrected Hitachi HF5000 scanning TEM (STEM) at the University of Arizona. The HF5000 is equipped with bright-field (BF), dark-field (DF), and secondary electron (SE) detectors as well as dual Oxford 100 mm2 windowless silicon-drift energy dispersive X-ray spectroscopy (EDX) detectors. We subjected sulfide grains to two distinct thermal regimes: 1) fast (<0.5 s) repeated thermal pulses from room temperature to 1100 °C and back to simulate the short-duration high-temperature effects of micrometeoroid impacts and 2) slow, step-heating with a ramp rate of 100 °C/s, holding the sample for two minutes each at 200 °C, 550 °C, 610 °C, 750 °C, 950 °C, and 988 °C to investigate the behavior of sulfides at several known, relevant exsolution and eutectic temperatures [9]. We imaged the samples before and after heating, collected EDX maps to understand changes in chemistry resulting from heating, and recorded videos of the thermal events. Results and Discussion: Sulfide samples that experienced a single rapid thermal pulse to 1100 °C formed Fe-Ni-rich and S-depleted pillars/whiskers with near-identical morphology (e.g., striated cones up to 1 µm in length and 500 nm in width) to those observed in space weathered Apollo, Itokawa, and Ryugu samples [7,8]. Subjecting whisker-bearing grains to a subsequent thermal pulse up to 1100 °C resulted in the complete destruction of all identified pillars. The implications for these results are that micrometeoroid bombardment alone may enable the formation of these morphologies on sulfide grains exposed on airless surfaces, and that these textures would not be preserved in grains experiencing multiple impacts/high-temperature events. Our step-heating regime provides insight into the mobility of sulfur during thermal events. Heating to 610 °C (below which pentlandite/pyrrhotite exsolves) resulted in the complete loss of sulfur from some grains while others formed core-shell structures with Fe-S-rich rims and Sdepleted, Fe-Ni-rich cores. This microstructure was maintained until EDX maps showed all sulfur was lost from the remaining grains at the Fe-FeS eutectic at 988 °C leaving an Fe-rich rim and Fe-Ni-rich core. These results may provide a pathway for the formation of S-depleted rims via micrometeorid bombardment in addition to solar wind irradiation, as has been proposed for other returned samples, e.g., [10]. In situ heating experiments of this type may also provide insight into the nature of S mobility on asteroidal parent bodies under a variety of thermal conditions. [ABSTRACT FROM AUTHOR]

Differences in dose homogeneity and irradiated volumes of target and surrounding normal tissues between 3D conformal radiation treatment planning and simulated non-graphic manual treatment planning were evaluated in 18 dogs with apocrine gland adenocarcinoma of the anal sac. Overall, 3D conformal treatment planning resulted in more homogenous dose distribution to target tissues with lower hot spots and dose ranges. Dose homogeneity and guarantee of not under-dosing target tissues with 3D conformal planning came at the cost, however, of delivering greater mean doses of radiation and of irradiating greater volumes of surrounding normal tissue structures. [ABSTRACT FROM AUTHOR]

Healthy bone healing is a remarkable, mechanically sensitive, scar-free process that leads rapidly to repair tissue of high mechanical quality and functionality, and knowledge of this process is essential for driving advances in bone tissue engineering and regeneration. Gaining this knowledge requires the use of models to probe and understand the detailed mechanisms of healing, and the tight coupling of biology and mechanics make it essential that both of these aspects are controlled and analysed together, using a mechanobiological approach. This article reviews the literature on in vitro models used for this purpose, beginning with two-dimensional (2D) cell culture models used for applying controlled mechanical stimuli to relevant cells, and detailing the analysis techniques required for understanding both substrate strain and fluid flow stimuli in sufficient detail to relate them to biological response. The additional complexity of three-dimensional (3D) models, enabling more faithful representation of the healing situation, can require correspondingly more sophisticated tools for mechanical and biological analysis, but has recently uncovered exciting evidence for the mechanical sensitivity of angiogenesis, essential for successful healing. Studies using explanted tissue continue to be vital in informing these approaches, providing additional evidence for the relevance of effects in biological and mechanical environments close to those in the living organism. Mechanobiology is essential for the proper analysis of models for bone regeneration, and has an exciting integrative role to play not only in advancing knowledge in this area, but also in ensuring successful translation of new tissue engineering and regenerative therapies to the clinic. [ABSTRACT FROM AUTHOR]

Mechanical boundary conditions are well known to influence the regeneration of bone and mechanobiology is the study of how mechanical or physical stimuli regulate biological processes. In vivo models have been applied over many years to investigate the effects of mechanics on bone healing. Early models have focused on the influence of mechanical stability on healing outcome, with an interest in parameters such as the magnitude of interfragmentary movement, the rate and timing of application of micromotion and the number of loading cycles. As measurement techniques have been refined, there has been a shift in orders of magnitude from investigations targeted at the organ level to those targeted at the tissue level and beyond. An understanding of how mechanics influences tissue differentiation during repair and regeneration crucially requires spatial and temporal knowledge of both the local mechanical environment in the healing tissue and a characterization of the tissues formed over the course of regeneration. Owing to limitations in the techniques available to measure the local mechanical conditions during repair directly, simulation approaches, such as the finite element method, are an integral part of the mechanobiologist's toolkit, while histology remains the gold standard in the characterization of the tissue formed. However, with rapid advances occurring in imaging modalities and methods to characterize tissue properties, new opportunities exist to better understand the role of mechanics in the biology of bone regeneration. Combined with developments in molecular biology, mechanobiology has the potential to offer exciting, new regenerative treatments for bone healing. [ABSTRACT FROM AUTHOR]

An intrathoracic mass was discovered as an incidental finding in a 14-year-old, spayed, female Rottweiler cross during evaluation of urinary incontinence. Computed tomography suggested a pericardial or pleural location and high adipose content of the mass. The mass was removed via lateral thoracotomy with partial pericardectomy and was diagnosed as a pericardial lipoma. The dog recovered well, and there was no evidence of recurrence approximately one year later. Adipose tumours of the heart and its associated structures are rare in dogs and have been associated with both successful and fatal outcomes. [ABSTRACT FROM AUTHOR]

It is generally accepted that nutrient enrichment of aquatic systems will lead to increased production at the top trophic level (fish). We found that in the wastewater enriched Bow River, Alberta rainbow trout ( Oncorhynchus mykiss) biomass increased over 25-fold, and brown trout ( Salmo trutta) biomass increased 5-fold, however total sportfish biomass did not increase below the nutrient input point source. This was due to a dramatic downstream decrease in mountain whitefish ( Prosopium williamsoni) biomass to 2% of the average biomass upstream of the municipal effluent source. The spatial pattern over a 177-km river section encompassing the city of Calgary, showed that the increase in trout abundance approximately tracked the expected nutrient concentrations in the river, but with a downstream lag of 20–30 km. Mountain whitefish biomass over the 177 km was inversely related to the dominant trout species, rainbow trout. Invertebrate abundance, macrophyte biomass and phytoplankton biomass all increased below the wastewater treatment plant outfalls. However, periphyton data were highly variable and showed no response. We propose several hypotheses as regards the factors that may have led to the decrease in mountain whitefish, based on the data from all trophic levels and the spatial pattern for fish biomass. Proposed factors influencing the mountain whitefish decline were; altered competitive ability because of macrophyte abundance, ammonia toxicity and barriers to movement (weirs). [ABSTRACT FROM AUTHOR]

An 8-month-old castrated male Saint Bernard was evaluated for bilateral hind limb lameness. Lameness was ascribed to bilateral metatarsal rotational abnormalities on the basis of the physical examination and radiographic evaluations. Staged, bilateral deformity correction and tarsometatarsal arthrodeses were performed using circular external skeletal fixators. The dog's gait improved following surgery and the fixators were removed 3 (left hind paw) and 4 (right hind paw) months following surgery. Twenty months after the initial surgery, the owner reported that the dog was walking well without apparent lameness. Previous reports suggest that metatarsal rotation is untreatable; however, our results suggest that surgical correction of this deformity can substantially improve limb function in dogs affected with metatarsal rotation. [ABSTRACT FROM AUTHOR]

Background: Large interfragmentary movements may delay bone-healing. The hypothesis of the present study was that a reduction of interfragmentary movements, especially of torsional rotation and bending angles, would support the healing process and lead to improved healing following unreamed tibial nailing. The objective of this study was to investigate healing of an unstable tibial osteotomy site following stabilization with unreamed nailing with a modified tibial device that had angle stable holes for the locking bolts. We compared those findings with healing after stabilization of such sites with standard unreamed tibial nailing. The duration of the study period was nine weeks.Methods: The site of a standardized displaced osteotomy (3-mm gap) in twelve ovine tibiae was stabilized with unreamed tibial nailing: six animals were treated with a modified nail that had angle stable holes for the locking bolts, and six were treated with standard unreamed tibial nailing. In vivo gait analysis with optical measurements of interfragmentary movements and simultaneous measurements of ground reaction parameters were performed three days after the operation and once weekly afterward. After the animals were killed at nine weeks, the treated and contralateral tibiae were explanted, the implants were removed, and radiographs were made and evaluated for bridged cortices. Each pair of tibiae was also mechanically tested until torsional failure, after which the whole callus region was subjected to histological and histomorphometric analysis.Results: Throughout the examination period, the interfragmentary movements in all directions were significantly smaller in the group treated with the angle stable tibial nail than they were in the group treated with standard unreamed tibial nailing. The limbs treated with the angle stable tibial nails returned to almost full weight-bearing during the period of the investigation, whereas those treated with standard nailing did not. Histomorphometric analysis, radiographic data, and mechanical testing showed superior bone-healing following treatment with the angle stable tibial nail.Conclusions: Use of an angle stable tibial nail may help to reduce interfragmentary movements in vivo and thus lead to superior bone-healing compared with that following standard unreamed tibial nailing. [ABSTRACT FROM AUTHOR]

Background: Large interfragmentary movements may delay bone-healing. The hypothesis of the present study was that a reduction of interfragmentary movements, especially of torsional rotation and bending angles, would support the healing process and lead to improved healing following unreamed tibial nailing. The objective of this study was to investigate healing of an unstable tibial osteotomy site following stabilization with unreamed nailing with a modified tibial device that had angle stable holes for the locking bolts. We compared those findings with healing after stabilization of such sites with standard unreamed tibial nailing. The duration of the study period was nine weeks. Methods: The site of a standardized displaced osteotomy (3-mm gap) in twelve ovine tibiae was stabilized with unreamed tibial nailing: six animals were treated with a modified nail that had angle stable holes for the locking bolts, and six were treated with standard unreamed tibial nailing. In vivo gait analysis with optical measurements of interfragmentary movements and simultaneous measurements of ground reaction parameters were performed three days after the operation and once weekly afterward. After the animals were killed at nine weeks, the treated and contralateral tibiae were explanted, the implants were removed, and radiographs were made and evaluated for bridged cortices. Each pair of tibiae was also mechanically tested until torsional failure, after which the whole callus region was subjected to histological and histomorphometric analysis. Results: Throughout the examination period, the interfragmentary movements in all directions were significantly smaller in the group treated with the angle stable tibial nail than they were in the group treated with standard unreamed tibial nailing. The limbs treated with the angle stable tibial nails returned to almost full weight-bearing during the period of the investigation, whereas those treated with standard nailing did not. Histomorphometric analysis, radiographic data, and mechanical testing showed superior bone-healing following treatment with the angle stable tibial nail. Conclusions: Use of an angle stable tibial nail may help to reduce interfragmentary movements in vivo and thus lead to superior bone-healing compared with that following standard unreamed tibial nailing. Clinical Relevance: The reduction of the interfragmentary movements by unreamed nailing seems to combine the advantages of favorable biological conditions with the mechanical advantages of systems with a higher biomechanical stiffness. The general concept of "optimizing" interfragmentary movements by using unreamed nailing with angle stable bolts needs to be confirmed in a prospective randomized clinical investigation. [ABSTRACT FROM AUTHOR]

Phase explosions (PEs) have been observed at tens of microseconds delay after laser pulse arrival on carbon, aluminium, silicon, iron, copper, zinc, tin and lead targets ablated at an irradiance ~3×1013 W cm-2, delivered by 100 ps laser pulses at 532 nm wavelength. The PEs in lead and tin were accompanied by an emission that caused a massive photoelectric effect from copper plates that were positioned 20 and 40 cm away from the targets. Initial estimations suggest emitted photon energy around 10 eV. The phenomenon was also studied by direct imaging with an intensified charge-coupled device camera. Analysis of the PE event is given in terms of thresholds, critical exposures (i.e. number of laser shots required to cease observation of PE), angular profiles of UV-emission and ejected particulate velocities. The velocity of the ejected particulates was ~200 m s-1, which is about 100 times slower than the ion velocity. The fraction of mass removed via PE was ~90%. The observations and data analysis reported in this paper can hardly be explained without considering the phase boundaries and/or charge transport. This poses certain challenge to current thermal models of PEs. [ABSTRACT FROM AUTHOR]

Cost analysis has been frequently neglected in program evaluations but is currently of high relevance in policy decisions on quality assurance in medicine. The Ambulatory Care Medical Audit Demonstration (ACMAD) Project implemented and evaluated a program of medical record-based quality assurance in eleven sites for nine medical topics. Total direct costs for the project were $1.22 million over five years; indirect costs, $694,000. A computerized data system enabled disaggregation of the cost data by person, timing, type of work, project phase, health topic, health center, and research or operational nature. Of the costs incurred, 79% were for operational reasons, with 21% incurred for research reasons. Costs per audited case were 31% higher in hospitals than in neighborhood health centers. Audit topics of low per-case costs tended to have automated case findings, straightforward and limited abstracting, little need to examine multiple visits, and a low proportion of case-found patients ineligible for audit. [ABSTRACT FROM AUTHOR]

As in kannada, the earliest Tamil versions of the Mahābhārata were in the Sanskrit campū style of verse and prose. Tradition has it that one such work appeared in the early days of Tamil literature when the last of three academies or sangams flourished in the south under royal patronage at Madurai, the capital city of the Pāṇdiyan kingdom. Epigraphical support for this view is found, it is thought, in line 29 of the panegyric referred to below, where there is a reference to a translation of the Mahābhārata into Tamil and the founding of a sangam. The extract comes from the Ciṉṉamaṉūr copper plate grants, which Dr. S. Krishṇnasāmi Ayyangar thinks belong to the tenth century. Certain citations in the commentary of the learned Nacciṉārkkiṉiyar on sūtras 17 and 21 of Tolkāppiyam, iii, 2, may have come from this early Sangam Pāratam, as they have the true Sangam ring. So thinks M. Rāghava Ayyangar, who has done good work in dating Tamil literature. The verse of the Sangam Pāratam consisted, it is said, mainly of quatrains in veṇpā metre interspersed with passages of akaval, akaval being the declamatory form of verse and veṇpā the form nearer normal speech. Citations in both these forms are found in the commentary just referred to, the first said to be from “Peruntēvaṉār” (reputed author of the Sangam Pāratam) and the rest from “Pāratam”. Peruntēvanār was a name common among poets of Sangam times and the author of the Pāratam was consequently referred to as the one who composed the Pāratam to distinguish him from his namesakes. Two of his poems are included in two of the eight old anthologies of mostly fugitive verse and five of the invocatory poems are his, all eight poems being in akaval. The Sangam Pāratam is also referred to as Pāratavepāṇ, because most of its verse is said to have been in the veṇpā metre. [ABSTRACT FROM PUBLISHER]

Focuses on issues regarding contraceptive implants. Comments and criticism on the editorial of David Bromham on contraceptive implants; Views on provider dependent contraception; Importance of information on choice making; Impact of provider dependent and long acting contraception on the freedom of choice.