Compositional and Mineralogical Effects on Ice Nucleation Activity of Volcanic Ash

Volcanic ash produced during explosive eruptions may serve as ice nuclei in the atmosphere, contributing to the occurrence of volcanic lightning due to tribocharging from ice&ndash;ice or ice&ndash;ash collisions. Here, different ash samples were tested using deposition-mode and immersion-mode ice nucleation experiments. Results show that bulk composition and mineral abundance have no measurable effect on depositional freezing at the temperatures tested, as all samples have similar ice saturation ratios. In the immersion mode, there is a strong positive correlation between K₂O content and ice nucleation site density at &minus;25 &deg;C and a strong negative correlation between MnO and TiO₂ content at temperatures from &minus;35 to &minus;30 &deg;C. The most efficient sample in the immersion mode has the highest surface area, smallest average grain size, highest K₂O content, and lowest MnO content. These results indicate that although ash abundance&mdash;which creates more available surface area for nucleation&mdash;has a significant effect on immersion-mode freezing, composition may also contribute. Consequently, highly explosive eruptions of compositionally evolved magmas create the necessary parameters to promote ice nucleation on grain surfaces, which permits tribocharging due to ice&ndash;ice or ice&ndash;ash collisions, and contribute to the frequent occurrence of volcanic lightning within the eruptive column and plume during these events.</p

Constraining the Potential Liquid Water Environment at Gale Crater, Mars

The Mars Science Laboratory (MSL) Rover Environmental Monitoring Station (REMS) has now made continuous in situ meteorological measurements for several Martian years at Gale crater, Mars. Of importance in the search for liquid formation are REMS’ measurements of ground temperature and inâ air measurements of temperature and relative humidity, which is with respect to ice. Such data can constrain the surface and subsurface stability of brines. Here we use updated calibrations to REMS data and consistent relative humidity comparisons (i.e., with respect to liquid versus with respect to ice) to investigate the potential formation of surface and subsurface liquids throughout MSL’s traverse. We specifically study the potential for the deliquescence of calcium perchlorate. Our data analysis suggests that surface brine formation is not favored within the first 1648 sols as there are only two times (sols 1232 and 1311) when humidityâ temperature conditions were within error consistent with a liquid phase. On the other hand, modeling of the subsurface environment would support brine production in the shallow subsurface. Indeed, we find that the shallow subsurface for terrains with low thermal inertia (Î â ²300 J mâ 2 Kâ 1 sâ 1/2) may be occasionally favorable to brine formation through deliquescence. Terrains with Î â ²175 J mâ 2 Kâ 1 sâ 1/2 and albedos of â ³0.25 are the most apt to subsurface brine formation. Should brines form, they would occur around Ls 100°. Their predicted properties would not meet the Special nor Uncertain Region requirements, as such they would not be potential habitable environments to life as we know it.Plain Language SummaryThe Mars Science Laboratory (MSL) has now made continuous measurements of the local weather at Gale crater, Mars. Such measurements can help guide our search for the formation of liquid water on presentâ day Mars. Specifically, when the right temperature and humidity conditions are met, certain salts can take in water vapor from the atmosphere to produce liquids. Here we use data from MSL along with experimental results on the stability of a Marsâ relevant salt to search for time periods when liquids could potentially form at the surface. Additionally, we use simulations and MSL data to understand the potential to form such liquids in the subsurface. Our results suggest that surface formation of liquids is unlikely throughout MSL’s travels; however, the shallow subsurface may experience conditions that would allow for liquid formation. Not much liquid would form, though, and the properties of these liquids would not permit life as we know it to persist.Key PointsMeasured surface environmental conditions at Gale crater are not favorable to brine formation via deliquescence of calcium perchlorateLiquids may have formed in the shallow subsurface of low thermal inertia units within MSLâ traversed terrainsMSL may best find liquids in the subsurface of units with thermal inertia less than or equal to 175 J mâ 2 Kâ 1 sâ 1/2 and albedo > 0.25 around Ls 100°Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144585/1/jgre20830-sup-0001-supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144585/2/jgre20830_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144585/3/jgre20830.pd

Correlation between Targeted qPCR Assays and Untargeted DNA Shotgun Metagenomic Sequencing for Assessing the Fecal Microbiota in Dogs

DNA shotgun sequencing is an untargeted approach for identifying changes in relative abundances, while qPCR allows reproducible quantification of specific bacteria. The canine dysbiosis index (DI) assesses the canine fecal microbiota by using a mathematical algorithm based on qPCR results. We evaluated the correlation between qPCR and shotgun sequencing using fecal samples from 296 dogs with different clinical phenotypes. While significant correlations were found between qPCR and sequencing, certain taxa were only detectable by qPCR and not by sequencing. Based on sequencing, less than 2% of bacterial species (17/1190) were consistently present in all healthy dogs (n = 76). Dogs with an abnormal DI had lower alpha-diversity compared to dogs with normal DI. Increases in the DI correctly predicted the gradual shifts in microbiota observed by sequencing: minor changes (R = 0.19, DI 2, DI > 5, and DI > 8, respectively), compared to dogs with a normal DI (DI < 0, all targets within the RI), as higher R-values indicated larger dissimilarities. In conclusion, the qPCR-based DI is an effective indicator of overall microbiota shifts observed by shotgun sequencing in dogs

Demographic factors associated with joint supplement use in dogs from the Dog Aging Project

Osteoarthritis (OA) is one of the most prevalent age-related chronic conditions that afflict companion dogs, and multiple joint supplements are available to prevent or treat OA, though the efficacy of these treatments is controversial. While the demographic factors that are associated with OA diagnosis are well established, the factors that are associated with joint supplement use are not as well studied. Using data collected from the Dog Aging Project, we analyzed owner survey responses regarding joint supplement administration and OA diagnosis for 26,951 adult dogs. In this cross-sectional analysis, logistic regression models and odds-ratios (OR) were employed to determine demographic factors of dogs and their owners that were associated with joint supplement administration. Forty percent of adult dogs in our population were given some type of joint supplement. Perhaps not surprisingly, dogs of older age, larger size, and those that were ever overweight were more likely to receive a joint supplement. Younger owner age, urban living, owner education, and feeding commercial dry food were associated with a reduced likelihood of administration of joint supplements to dogs. Interestingly, mixed breed dogs were also less likely to be administered a joint supplement (OR: 0.73). Dogs with a clinical diagnosis of OA were more likely to receive a joint supplement than those without a reported OA diagnosis (OR: 3.82). Neutered dogs were more likely to have a diagnosis of OA, even after controlling for other demographic factors, yet their prevalence of joint supplement administration was the same as intact dogs. Overall, joint supplement use appears to be high in our large population of dogs in the United States. Prospective studies are needed to determine if joint supplements are more commonly administered as a preventative for OA or after an OA clinical diagnosis

Invasive tracheal neoplasia in eight cats: descriptive cases and review of the current literature

Case series summary This case series describes eight cases of invasive tracheal neoplasia that were recognized between the years 1989 and 2014 from a single tertiary referral hospital. This is a disproportionately high number of cases compared with the total number of reports in the current literature. Relevance and novel information Invasive tracheal neoplasia is uncommonly diagnosed in domestic cats. Feline tracheal tumors mimic other upper respiratory diseases making diagnosis challenging. Prognosis is guarded to grave, with most cats surviving less than 1 month after beginning treatment. Severe respiratory distress in cats often warrants humane euthanasia. Appropriate clinical suspicion and awareness can expedite diagnoses leading to prolonged survival rates with appropriate treatments. This case series represents the largest number of feline tracheal tumors reported and also describes the first unique histological presentation of what the authors believe to be a poorly differentiated tracheal carcinoma

Medical management of gastrinoma in a cat

Case summary A 7-year-old male castrated domestic short-haired cat was evaluated for a 4 week history of intermittent vomiting, ptyalism, lethargy and weight loss. Serum biochemistry revealed mild mixed hepatopathy. Abdominal ultrasonography identified multiple heterogeneous hepatic masses and a linear, hyperechoic focus with associated reverberation artifact in the wall of the stomach consistent with a gastric ulcer. Serum gastrin concentrations were markedly increased. Cytologic interpretation of a fine-needle aspirate of the hepatic masses was consistent with neuroendocrine neoplasia, and a diagnosis of gastrinoma was established. Deterioration of the cat’s condition, despite at-home acid-suppressant therapy, led to hospitalization. The cat was initially stabilized with intravenous crystalloid fluid therapy, maropitant, pantoprazole and octreotide. A continuous radiotelemetric intragastric pH monitoring system was used to monitor the response of intragastric pH to therapy. Long-term therapy was continued with omeprazole (orally q12h), octreotide (subcutaneously q8h) and thrice-weekly toceranib administered orally. Toceranib therapy led to gastrointestinal upset and was discontinued. Gastric ulceration resolved within 8 weeks, and palliation of clinical signs was achieved for approximately 5 months. Relevance and novel information Including this report, only six cases of feline gastrinoma have been reported in the veterinary literature. Little is known regarding non-surgical therapy, and octreotide has not been previously reported for medical management of feline gastrinoma. Results of intragastric pH monitoring and clinical improvement suggest that medical therapy using octreotide and proton pump inhibitors represents a novel therapeutic option for cats with gastrinoma where surgical excision is not feasible

Use of octreotide for the treatment of protein‐losing enteropathy in dogs: Retrospective study of 18 cases

Abstract Background More than 50% of dogs with protein‐losing enteropathy (PLE) fail to respond to standard therapies. Octreotide, a somatostatin analogue, is used in cases of intestinal lymphangiectasia (IL) in humans with some success. Objectives Describe the use of octreotide in dogs with PLE including reason for and details of prescription, adverse effects, and apparent response. Animals Eighteen dogs with PLE, 13 with histopathology available. Ninety‐two percent (12/13) had IL diagnosed on biopsy. All 13 dogs had intestinal inflammatory infiltrates noted. Methods Multicenter, retrospective, descriptive study. Cases were volunteered for inclusion by individual attending veterinarians who reported the use of octreotide in cases of PLE. Results In 16/18 (89%) cases octreotide was prescribed to PLE dogs with a clinical suspicion or confirmed diagnosis of IL that were refractory to standard therapies. Median serum albumin at the time of octreotide prescription was 1.7 g/dL (range, 1.0‐3.1 g/dL). The median dose of octreotide prescribed was 20 μg/kg, SQ, daily with a range of 4‐39 μg/kg, SQ, daily. Adverse effects were noted in 3/18 (17%, 95% CI [4%, 41%]) of dogs; discontinuation of the drug was necessary in 1 dog. Improvement in clinical signs was noted in 6/12 (50%, 95% CI [21%, 79%]). Conclusions and Clinical Importance Octreotide was most commonly prescribed to dogs with PLE and suspected or confirmed IL that had failed to respond to standard therapies. Though a benefit to PLE dogs cannot be confirmed, octreotide was well tolerated by the majority of dogs at the doses prescribed in this study

Evaluation of a long‐acting injectable formulation of omeprazole in healthy dogs

Abstract Background To evaluate the efficacy of a single intramuscular adminsitration of long‐acting omeprazole (LA‐OMEP) in increasing gastric pH in dogs. Hypothesis We hypothesized that LA‐OMEP would meet in healthy dogs the clinical goals defined for human patients for treatment of gastroduodenal ulceration. Animals Nine healthy research dogs. Methods Prospective experimental study. Dogs were given a 4 mg/kg intramuscular injection of LA‐OMEP. Intragastric pH was continuously recorded on treatment days 0 to 7. Daily mean pH and mean percentage time (MPT) intragastric pH was ≥3 or ≥4 were determined. Results The mean onset of action for the LA‐OMEP was 98.11 min (SD 46.39). The mean number of days the dogs' pH met established goals for MPT pH ≥3 was 5.5 days (range, 3‐7) and 5.25 days for MPT pH ≥4 (range, 3‐7). Long‐acting omeprazole met the human clinical goals pH ≥3 for 72 hours in 8/8 of the dogs and MPT pH ≥4 for 96 hours in 7/8 of dogs. Conclusions and Clinical Importance The LA‐OMEP formulation produced gastric acid suppression in healthy dogs for an average of 5 days and up to 7 days, after a single intramuscular injection. No major adverse effects were observed

Double‐blinded placebo‐controlled clinical trial of prophylactic omeprazole in dogs treated surgically for acute thoracolumbar intervertebral disc extrusion

Abstract Background Proton pump inhibitors are administered prophylactically in dogs treated surgically for acute thoracolumbar intervertebral disc extrusion (TL‐IVDE). However, their efficacy in decreasing gastrointestinal (GI) complications is unknown. Hypothesis Omeprazole does not decrease the frequency of GI complications compared to placebo in dogs treated surgically for acute TL‐IVDE. Animals Thirty‐seven client‐owned dogs undergoing hemilaminectomy for acute TL‐IVDE. Methods Randomized double‐blinded placebo‐controlled prospective clinical trial. Dogs received PO placebo or omeprazole at 1 mg/kg q12h for 5 days during hospitalization. Development of GI signs (e.g., diarrhea, vomiting, regurgitation, hematochezia, melena) was recorded daily. Clinicopathologic testing performed during hospitalization and at 2 and 4‐week re‐evaluations included: fecal occult blood, PCV, blood urea nitrogen/creatinine ratio, fecal calprotectin, canine pancreatic lipase immunoreactivity and fecal alpha‐1 proteinase inhibitor concentrations. Omeprazole and placebo groups were compared using chi‐squared or Fisher's exact tests. Results Gastrointestinal signs developed in 10/20 (50%) dogs in the omeprazole group and in 7/17 (41%) dogs in the placebo group (P = .59). Diarrhea was common (8/20 omeprazole, 5/17 placebo), hematochezia was rare (1/20 omeprazole, 1/17 placebo); melena was not observed. Clinicopathologic evidence suggestive of bleeding was present in 9/20 dogs treated with omeprazole and in 11/17 dogs that received placebo (P = .23). Fecal occult blood positivity was more common in dogs with GI signs (P = .03). Canine pancreatic lipase immunoreactivity was higher during hospitalization compared to re‐evaluations (P = .01). Conclusions and Clinical Importance Short‐term, prophylactic omeprazole treatment did not decrease clinically detectable GI complications in dogs with acute TL‐IVDE

Laboratory Studies of Brine Growth Kinetics Relevant to Deliquescence on Mars

Although previous studies have shown that the near-surface environmental conditions on Mars may permit salt deliquescence and therefore brine production, there is significant uncertainty in the kinetics of the process. Indeed, experimental studies have shown that deliquescence is either very rapid or too slow to be relevant to Mars. To resolve this uncertainty, we performed laboratory experiments to investigate the growth rate of Mars-relevant calcium perchlorate brines over a range of temperatures (184–273 K) and water vapor pressures (0.2–220 Pa). We show that the brine growth is faster at higher water vapor pressures and lower temperatures and for smaller particles. From our data, we determined a temperature-dependent net uptake coefficient for gas phase water molecules colliding with a perchlorate brine surface in the range of 3.8 × 10 ^−4 at 185 K to 4.2 × 10 ^−6 at 273 K. These values suggest that deliquescence on Mars is likely to be slow even when conditions thermodynamically permit a brine to form. We find that along the Curiosity rover traverse at Gale Crater, the near-surface conditions would only allow particles <1 μ m to fully deliquesce over a typical sol. At the higher-latitude Phoenix landing site, deliquescence may be 30% faster due to the higher water vapor pressures, but still, only micron-scale salt grains or coatings would be expected to deliquesce during a typical sol. These results suggest that brines formed via deliquescence on the surface of Mars are likely only present on small scales that may not be readily detected using conductivity or imaging techniques