Exploration of fs-laser ablation parameter space for 2D/3D imaging of soft and hard materials by tri-beam microscopy.

Tri-beam microscopes comprising a fs-laser beam, a Xe+ plasma focused ion beam (PFIB) and an electron beam all in one chamber open up exciting opportunities for site-specific correlative microscopy. They offer the possibility of rapid ablation and material removal by fs-laser, subsequent polishing by Xe-PFIB milling and electron imaging of the same area. While tri-beam systems are capable of probing large (mm) volumes providing high resolution microscopical characterisation of 2D and 3D images across exceptionally wide range of materials and biomaterials applications, presenting high quality/low damage surfaces to the electron beam can present a significant challenge, especially given the large parameter space for optimisation. Here the optimal conditions and artefacts associated with large scale volume milling, mini test piece manufacture, serial sectioning and surface polishing are investigated, both in terms of surface roughness and surface quality for metallic, ceramic, mixed complex phase, carbonaceous, and biological materials. This provides a good starting place for those wishing to examine large areas or volumes by tri-beam microscopy across a range of materials.

Sequencing of mRNA identifies re-expression of fetal splice variants in cardiac hypertrophy.

Cardiac hypertrophy has been well-characterized at the level of transcription. During cardiac hypertrophy, genes normally expressed primarily during fetal heart development are re-expressed, and this fetal gene program is believed to be a critical component of the hypertrophic process. Recently, alternative splicing of mRNA transcripts has been shown to be temporally regulated during heart development, leading us to consider whether fetal patterns of splicing also reappear during hypertrophy. We hypothesized that patterns of alternative splicing occurring during heart development are recapitulated during cardiac hypertrophy. Here we present a study of isoform expression during pressure-overload cardiac hypertrophy induced by 10 days of transverse aortic constriction (TAC) in rats and in developing fetal rat hearts compared to sham-operated adult rat hearts, using high-throughput sequencing of poly(A) tail mRNA. We find a striking degree of overlap between the isoforms expressed differentially in fetal and pressure-overloaded hearts compared to control: forty-four percent of the isoforms with significantly altered expression in TAC hearts are also expressed at significantly different levels in fetal hearts compared to control (P<0.001). The isoforms that are shared between hypertrophy and fetal heart development are significantly enriched for genes involved in cytoskeletal organization, RNA processing, developmental processes, and metabolic enzymes. Our data strongly support the concept that mRNA splicing patterns normally associated with heart development recur as part of the hypertrophic response to pressure overload. These findings suggest that cardiac hypertrophy shares post-transcriptional as well as transcriptional regulatory mechanisms with fetal heart development.

A computational study of odorant transport and deposition in the canine nasal cavity: implications for olfaction.

Olfaction begins when an animal draws odorant-laden air into its nasal cavity by sniffing, thus transporting odorant molecules from the external environment to olfactory receptor neurons (ORNs) in the sensory region of the nose. In the dog and other macrosmatic mammals, ORNs are relegated to a recess in the rear of the nasal cavity that is comprised of a labyrinth of scroll-like airways. Evidence from recent studies suggests that nasal airflow patterns enhance olfactory sensitivity by efficiently delivering odorant molecules to the olfactory recess. Here, we simulate odorant transport and deposition during steady inspiration in an anatomically correct reconstructed model of the canine nasal cavity. Our simulations show that highly soluble odorants are deposited in the front of the olfactory recess along the dorsal meatus and nasal septum, whereas moderately soluble and insoluble odorants are more uniformly deposited throughout the entire olfactory recess. These results demonstrate that odorant deposition patterns correspond with the anatomical organization of ORNs in the olfactory recess. Specifically, ORNs that are sensitive to a particular class of odorants are located in regions where that class of odorants is deposited. The correlation of odorant deposition patterns with the anatomical organization of ORNs may partially explain macrosmia in the dog and other keen-scented species.

The ELFIN Mission.

The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or heretoforth simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (∼93∘ inclination), nearly circular, low-Earth (∼450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (Torbit ∼ 90 min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50 keV to 5 MeV electrons with Δ E/E < 40% and a fluxgate magnetometer (FGM) on a ∼72 cm boom that measures magnetic field waves (e.g., EMIC waves) in the range from DC to 5 Hz Nyquist (nominally) with <0.3 nT/sqrt(Hz) noise at 1 Hz. The spinning satellites (Tspin ∼ 3 s) are equipped with magnetorquers (air coils) that permit spin-up or -down and reorientation maneuvers. Using those, the spin axis is placed normal to the orbit plane (nominally), allowing full pitch-angle resolution twice per spin. An energetic particle detector for ions (EPDI) measures 250 keV - 5 MeV ions, addressing secondary science. Funded initially by CalSpace and the University Nanosat Program, ELFIN was selected for flight with joint support from NSF and NASA between 2014 and 2018 and launched by the ELaNa XVIII program on a Delta II rocket (with IceSatII as the primary). Mission operations are currently funded by NASA. Working under experienced UCLA mentors, with advice from The Aerospace Corporation and NASA personnel, more than 250 undergraduates have matured the ELFIN implementation strategy; developed the instruments, satellite, and ground systems and operate the two satellites. ELFIN's already high potential for cutting-edge science return is compounded by concurrent equatorial Heliophysics missions (THEMIS, Arase, Van Allen Probes, MMS) and ground stations. ELFIN's integrated data analysis approach, rapid dissemination strategies via the SPace Environment Data Analysis System (SPEDAS), and data coordination with the Heliophysics/Geospace System Observatory (H/GSO) optimize science yield, enabling the widest community benefits. Several storm-time events have already been captured and are presented herein to demonstrate ELFIN's data analysis methods and potential. These form the basis of on-going studies to resolve the primary mission science objective. Broad energy precipitation events, precipitation bands, and microbursts, clearly seen both at dawn and dusk, extend from tens of keV to >1 MeV. This broad energy range of precipitation indicates that multiple waves are providing scattering concurrently. Many observed events show significant backscattered fluxes, which in the past were hard to resolve by equatorial spacecraft or non-pitch-angle-resolving ionospheric missions. These observations suggest that the ionosphere plays a significant role in modifying magnetospheric electron fluxes and wave-particle interactions. Routine data captures starting in February 2020 and lasting for at least another year, approximately the remainder of the mission lifetime, are expected to provide a very rich dataset to address questions even beyond the primary mission science objective.

Gallbladder and small intestinal regulation of biliary lipid secretion during intraduodenal infusion of standard stimuli.

The gallbladder and small intestine are reservoirs for the bile acid pool during its enterohepatic circulation and, as such, may regulate biliary secretion of bile acid. During studies of biliary bile acid secretion, a stimulus to gallbladder contraction is continuously infused into the duodenum. Under these conditions, it is assumed that the gallbladder is tonically contracted and that the rate of bile acid secretion into the duodenum equals the hepatic bile acid secretion rate. However, secretion rates vary by as much as 100%, depending upon which of two standard stimuli is used. Therefore, we studied the role of gallbladder emptying and small intestinal transit in determining biliary lipid secretion rate and composition during infusion of these stimuli in five healthy subjects. Each subject was studied with a liquid formula containing 40% of calories as fat, and with an amino acid solution for 10 h. Bile acid, phospholipid, cholesterol, and markers were measured in duodenal bile and hourly secretion rates were calculated by marker dilution technique. Real-time gallbladder sonographs and serum pancreatic polypeptide levels were obtained every 30 min. Small bowel transit time was estimated levels were obtained every 30 min. Small bowel transit time was estimated by the breath hydrogen response after giving lactulose intraduodenally.During liquid formula infusion, gallbladder emptying was more complete, small intestinal transit was faster, and pancreatic polypeptide levels were higher. Secretion rates of all lipids were greater and molar percent cholesterol was lower. For the combined data from both infusions, the secretory relationships of cholesterol to bile acid, cholesterol to phospholipid, and phospholipid to bile acid were curvilinear. We conclude that more complete gallbladder emptying and faster intestinal transit increase the enterohepatic cycling of bile acids and lower the molar percent cholesterol of bile. Some of the fluctuation observed in biliary lipid secretion rates, especially during amino acid infusion, is due to gallbladder refilling and emptying.

Pharmacotoxicology of clinically-relevant concentrations of obeticholic acid in an organotypic human hepatocyte system.

Nonalcoholic steatohepatitis (NASH) is an emerging health crisis with no approved therapies. Obeticholic acid (OCA), a farnesoid X receptor (FXR) agonist, shows promise in NASH trials. However, the precise mechanisms mediating OCA effects and impact on cholesterol metabolism are not fully understood. We explored the pharmaco-toxicological effects of OCA on patho-physiological pathways in hepatocytes using a previously described perfused organotypic liver system that allows culture in near-physiological insulin/glucose milieus, and exhibits drug responses at clinically-relevant concentrations. Primary hepatocytes experienced 48-hour exposure to OCA at concentrations approximating therapeutic (0.5µM) and supratherapeutic (10µM) levels. Global transcriptomics by RNAseq was complimented by cellular viability (MTT), CYP activity assays, and secreted FGF19 levels in the media. Dose-dependent, transcriptional effects suggested suppression of bile acid synthesis (↓CYP7A1, ↓CYP27A1) and increased bile efflux (↑ABCB4, ↑ABCB11, ↑OSTA, ↑OSTB). Pleiotropic effects included suppression of TGFß and IL-6 signaling pathways, and signatures suggestive of HDL suppression (↑SCARB1, ↓ApoAI, ↓LCAT) and LDL elevation (↑ApoB, ↓CYP7A1). OCA exhibited direct FXR-mediated effects with increased FGF19 secretion. Transcriptomics revealed regulation of metabolic, anti-inflammatory, and anti-fibrotic pathways beneficial in NASH, and predicted cholesterol profiles consistent with clinical findings. Follow-up studies under lipotoxic/inflammatory conditions would corroborate these effects in a disease-relevant environment.

The evolution to stool DNA testing for colorectal cancer.

Despite a variety of screening strategies and recent trends showing death rate stabilization, colorectal cancer still remains the second leading cause of overall cancer death. Current screening tools suffer from performance limitations, low patient acceptability, and marginal reliable access within the health care system. Noninvasive strategies present the lowest risk with the highest potential for patient satisfaction. However, serious implementation barriers exist requiring consistent programmatic screening, strict patient adherence, and poor sensitivity for adenomas. Colonoscopy remains an invasive screening test with the best sensitivity and specificity, but faces large financial costs, manpower requirements, patient access and adherence. Development of advanced molecular techniques identifying altered DNA markers in exfoliated colonocytes signify early or precancerous growth. Stool-based DNA testing provides an entirely noninvasive population-based screening strategy which patients can perform easier than faecal occult blood testing (FOBT). Large-scale prospective randomized control trials currently pending should help characterize accurate test performance, screening intervals, cost-effectiveness, direct comparison to FOBT and analysis of patient adherence. As tumour development pathways and potential target genes are further elucidated, refinements in multi-assay stool-based DNA testing portend enhanced test characteristics to detect and treat this genetically heterogeneous disease.

Colorectal cancer and noncancer patients have similar labeling indices by microscopy and computed image analysis.

The labeling index (LI), a microscopic measurement of proliferative activity in colonic crypts, is proposed as an indicator of colonic cancer risk. Computed image analysis of proliferative regions is less labor intensive and more objective than is direct microscopy but has not been validated for labeling indices by direct comparison. The authors compared colonic crypt proliferation in 26 cancer and 13 noncancer patients by using Ki-67 monoclonal antibody (McAb) labeling of flat mucosa obtained from surgically removed, frozen specimens. In cancer patients, the mucosa specimen was excised 10 cm away from the tumor, and the LI was determined microscopically for the whole crypt, the upper two thirds, and the upper one third of 15 crypts. Nuclear antigen levels of 15 whole crypts were determined by using the CAS-200 computed image analyzer (Cell Analysis Systems, Elmhurst, IL). Cancer and noncancer specimens were compared as were microscopically determined LI and stained nuclei specimens by using image analysis. No statistically significant difference in proliferative activity of whole crypts, or the upper two thirds of crypts, was observed between cancer specimens and noncancer specimens from using either technique. However, a significant correlation existed between microscopic analysis and computed image analysis of labeled nuclei. Computed image analysis using Ki-67 McAb labeling can be used instead of microscopy to determine crypt LI, but neither method can be used to distinguish cancer specimens from noncancer specimens.

Colonic bicarbonate output as a test of disease activity in ulcerative colitis.

No available test objectively measures impairment of function of the inflamed colonic mucosa in ulcerative colitis. To study function we assessed rectal bicarbonate output by rectal dialysis in the presence of water and bacterial fatty acid (n-butyrate) in 21 controls, 18 patients with acute ulcerative colitis, 12 patients with ulcerative colitis in remission, and 12 patients with other forms of colitis. In acute ulcerative colitis, compared with controls, bicarbonate output and pH was reduced (p less than 0.001); stimulated bicarbonate output with bacterial fatty acid (incremental bicarbonate output) was reduced by 80% in acute ulcerative colitis (p less than 0.01). Results indicate that bicarbonate output is a useful and selective test of mucosal function in acute ulcerative colitis. A diminished incremental bicarbonate output with n-butyrate supports the view of inadequate oxidation of bacterial fatty acids in vivo by the mucosa in ulcerative colitis. Whether the test will prove to be an index of prognosis or will aid choice between medical or surgical therapy requires further study.

Zinc deficiency is associated with suppression of colonocyte proliferation in the distal large bowel of rats.

As zinc status may influence susceptibility to colon cancer, we examined the effect of dietary zinc deficiency on the proliferation of epithelial cells (colonocytes) in the large bowel of rats. When compared to feed-restricted rats, those with zinc deficiency showed a significant reduction in proliferation in the distal colon as assessed by accumulated metaphase arrest and crypt cell production rates in vivo. Zinc deficiency had no apparent effect on thymidine kinase activity in colonocytes but was accompanied by minor changes in fecal mass and fecal pH. In rats, zinc deficiency is associated with a reduction in the rate of proliferation of colonocytes in the distal colon.

Colorectal cancer. Identifying and screening high-risk patients.

Colorectal carcinoma is a major cause of cancer-related morbidity and mortality in the United States. High-risk patients should be appropriately identified and screened. Current recommendations from the American Cancer Society for the average-risk patient include both digital rectal examination and fecal occult blood testing annually beginning at age 40, as well as flexible sigmoidoscopy every 3 to 5 years beginning at age 50 after two normal annual examinations. If any of these tests yield positive results, complete examination of the colon with colonoscopy is indicated. The reliability, sensitivity, and cost-effectiveness of both digital examinations and stool occult blood testing have not been reported to be adequate for screening large populations. A more practical approach may be to omit stool testing and recommend screening with flexible sigmoidoscopy for average-risk patients aged 50 and older. Patients with distal adenomas should undergo colonoscopy and polypectomy as necessary, with follow-up colonoscopy determined by the number of polyps and success in removal.

Observing executive activity in a simple assembly task.

Performance of a group of adult trainees in a workshop for mentally retarded persons and that of an equivalent-MA group of third-grade children was observed in a toy construction task. Performances were video taped and subsequently coded for executive activity and other classes of behavior. A range of executive activities was identified, and these proved to be a powerful influence in discriminating between the groups. Other analyses of event sequences examined where executive activity occurred and which types of events typically followed such activity.

Effects of training in use of executive strategies on a verbal memory problem resulting from closed head injury.

This case study reports attempts to improve the recall performance of an adolescent (GC) who had suffered a closed-head injury. GC had a very limited range of ways of processing both spoken and written information and showed significant recall problems. Initial training in the use of strategies for list learning resulted in improvement in paired-associate recall but showed that initiation and use of the newly learned strategies would not occur without prompting. Executive strategy training was provided to improve GC's ability to identify a memory problem and to initiate a general plan for dealing with that problem. This training involved consideration of task analysis, strategy selection and initiation, and monitoring of strategy use. Evidence of long-term maintenance of improvement in level of recall on both paired-associate and free recall tests was noted following the executive strategy training.

Production and physical characteristics of composted poultry carcases.

1. Experiments were designed to determine whether composting could be a safe and effective method for the disposal of poultry carcases in the UK climate. Laying hen carcases (125) were composted in a wooden compost bin over autumn and winter months, using the United States Department of Agriculture method. 2. The process took 8 weeks and effectively decomposed the carcases to leave only leg and breast bones. The compost was turned once, which ensured that all the material reached the high temperatures (60 degrees to 70 degrees C) required to control pathogens. Salmonella was fully heat-inactivated, indicating that many poultry-associated bacterial pathogens would also have been inactivated. 3. It is concluded that this method is suitable for use in the UK and provides a sanitised fertiliser supplement.

Tonsillectomy and adenoidectomy pathway plan of care for the pediatric patient in day surgery.

The care of children undergoing tonsillectomy and adenoidectomy (T&A) in the day surgery setting can be costly, due in a large part to the length of stay after surgery. A clinical pathway standardizes the length of stay and, therefore, directly controls costs associated with outpatient T&A. A T&A pathway plan of care was developed at one institution to (1) decrease the cost of the procedure, (2) improve parent/patient satisfaction, and (3) maintain or improve the quality of care.

Nitrite from inflammatory cells--a cancer risk factor in ulcerative colitis?

Elevated levels of luminal nitrite and a lowered luminal pH were found in 77 percent of patients with acute ulcerative colitis. No luminal nitrite was found in healthy control subjects. Nitrites are a secretory product of activated macrophages and neutrophils of the lamina propria, whereas the lowered luminal pH is due to diminished bicarbonate formation by impaired colonocytes. A hypothesis is put forward that nitrites, lowered pH, and bacterial amines are conducive to formation of carcinogenic n-nitroso compounds, which reflect a cancer risk in patients with ulcerative colitis dependent on the type and extent of inflammatory cell activation as well as metabolic impairment of colonic epithelial cells.

Antral gastrin concentrations in duodenal ulcer patients after cimetidine and highly selective vagotomy.

Post-prandial serum levels of gastrin, the main hormonal stimulator of acid secretion, have been shown to be significantly elevated after HSV compared with controls. The mechanism for this elevation is not known but could be secondary to an increased antral gastrin concentration (AGC). In this study AGCs were measured in endoscopic biopsies before and at intervals of 6 and 32 weeks after HSV in 12 patients with duodenal ulcer. Results were compared with 13 normal controls and 12 duodenal ulcer patients treated with cimetidine for 6 weeks. Blood was taken for fasting serum gastrin concentration at each endoscopy. In the HSV group AGC significantly increased on both postoperative occasions when compared with pre-operative values (P less than 0.01). AGC also showed a significant correlation with time after HSV (r = 0.71; P less than 0.01). Only one patient, who had a persistent duodenal ulcer, failed to show an increase in AGC. Cimetidine failed to increase AGCs in duodenal ulcer patients after 6 weeks of treatment. However, a subgroup (n = 7) of cimetidine-treated patients with low pretreatment AGCs, below 10 ng/mg, did show a significant rise at 6 weeks (P less than 0.05). Fasting serum gastrin levels did not change significantly in any of the three groups. It is concluded that HSV causes a significant increase in AGC with time.

Clinical evaluation of the 14C-Triolein Breath Test: a critical analysis.

Twenty-two hospital patients without gastrointestinal symptoms and fourteen patients with clinically suspected fat malabsorption were studied using the 14C-Triolein Breath Test and three day fecal fat estimation. The 14C-Triolein Breath Test was 100% sensitive and 86% specific for fat malabsorption. Three day fecal fat estimations were 86% sensitive and 91% specific. These data confirm the high sensitivity and specificity obtained using the 14C-Triolein Breath Test. The speed and convenience of the 14C-Triolein Breath Test plus acceptable sensitivity and specificity make this a practical screening test to detect fat malabsorption.