Morphometric analysis and application in galaxy evolution and high-redshift surveys.

In this thesis, I will present my research work with statistical analysis towards a galaxy’s morphology and its morphometric. The first part would be with the galaxy morphometric and have heavy focus with one particular software: Source Extractor. Source Extractor was compared to GALFIT in order to see how accurate and precise we would expect the software to be with effective radii, scale length, inclination,position angle, and major and minor axes. This is towards preparation for future surveys with expectation of a large boom in galaxy discovery with the new observatories to be online (EUCLID, LSST, JWST, etc.). From our understanding, Source Extractor is neither accurate nor precise enough to consider its initial computed parameters to be true. However, it does hold to see if there any sort of correlation or trend within the population. On the second part, we do scale-invariant morphological calculations on some galaxies that are high-redshift and ultra-luminous. We do computed statistical analytics to find and be certain of the morphological parameters. We only use Gini value and asymmetry. However, we do see more possible correlation with Gini and asymmetry in such epoch, yet very uncertain. However, just with these characteristics, this sample has an unusual pattern from what was expected, and this has an implication that morphological parameters may be useful for further surveys, in that they can help identify the z~8 redshift galaxies with this unique characteristic; however, we may need a larger sample size to be more certain, which is difficult to do as it is difficult to detect and discern a high-redshift galaxy

EXAMINATION OF THE b COEFFICIENT IN GaP CRYSTAL UTILIZING SINGLE AND DOUBLE PHOTON ABSORPTION

A laser of 0.800 mm at 100 fs is utilized in obtaining a b coefficient in a GaP crystal associated with double photon absorption. Data is collected for the incident power of the laser for both single and double photon absorption, and it is plotted against the signal generated in the photodiode containing the GaP crystal. The slope of such a plot is employed in calculating b with equations derived in the theoretical model that is unique to the present work. The data for single photon absorption is utilized in calculating the thickness of the GaP crystal, while the data for double photon absorption is directly utilized in the calculation of b coefficient. The present work yields a numerical value for the absorption coefficient for double photon absorption, b

Measurement of tissue oxygenation in isolated rat hearts using near infrared spectroscopy

New techniques involving Near Infrared Spectroscopy (NIRS) and imaging are rapidly evolving for a large number of new clinical applications. These techniques, based upon nearinfrared light transmission through biological tissue, aim to monitor the hemoglobin and myoglobin concentration changes due to particular physiological state. Clinical applications regard, for instance, the monitoring of muscles and cerebral oxygenation, functional brain activation studies and heart perfusion research. Recently, some works presented tissue oxygenation studies in beating or arrested isolated porcine hearts. In our work we present the design and realization of a dedicated NIRS system for the myocardial perfusion analysis of isolated, saline solution perfused beating rat hearts; in this case the absence of blood allows for unambiguous measurement of tissue myoglobin oxygenation. The presented prototype is portable, low cost, battery operated and permits the measurement of both oxy and deoxy myoglobin concentration changes during imposed regional or global ischemia and reperfusion

The Sizes of z ∼ 9-10 Galaxies Identified in the Brightest of Reionizing Galaxies (BoRG) Survey

Redshift z = 9-10 object selection is the effective limit of Hubble Space Telescope (HST) imaging capability, even when confirmed with Spitzer. If only a few photometry data points are available, it becomes attractive to add criteria based on their morphology in these J- and H-band images. One could do so through visual inspection, a size criterion, or alternate morphometrics. We explore a vetted sample of Brightest of Reionizing Galaxies (BoRG) z ∼ 9 and z ∼ 10 candidate galaxies and the object rejected by Morishita+ to explore the utility of a size criterion in z = 9-10 candidate selection. A stringent, point-spread function (PSF)-corrected effective radius criterion (re \u3c 0″.3) would result in the rejection of 65%-70% of the interlopers visually rejected by Morishita et al. It may also remove up to ∼20% of bona fide brightest (L ≫ L∗) z = 9 or 10 candidates from a BoRG selected sample based on the Mason et al. luminosity functions, assuming the Holwerda et al. z ∼ 9 size-luminosity relation. We argue that including a size constraint in lieu of a visual inspection may serve in wide-field searches for these objects in, e.g., Euclid or HST archival imaging with the understanding that some brightest (L ≫ L∗) candidates may be missed. The sizes of the candidates found by Morishita et al. follow the expected size distribution of z ∼ 9 for bright galaxies, consistent with the log normal in Shibuya et al. and single objects. Two candidates show high star formation surface density (ΣSFR \u3e 25M⊙ kpc-2) and all merit further investigation and follow-up observations

Potential role of low kV ex vivo micro-CT for 3D morphometry of paraffin embedded coronary vessels before histology

Purpose: Micro CT is an established tool for non destructive 3D inspection of small specimens. Aim of the study was to demonstrate that despite its limitations in differentiation of soft materials, micro CT can reliably display coronary vessel structure and surrounding tissues after paraffin embedding. Data were obtained from coronary specimens of pig, physical phantoms and numerical simulations. Preliminary images with dual-energy techniques are also shown. Methods: A micro CT scanner built by our group was used for the experiments. The x-ray tube was set up in the range of 20-50 kV; the voxel size was set to 21 μm. A phantom composed of formalin fixed fat and myocardium of rat, dehydrated and paraffin embedded, was used to measure the contrast of different tissues with respect to background. Similar acquisitions were simulated numerically. Real samples of pig excised coronary arteries were processed in the same way and acquired with the same settings; resulting images were compared to those obtained by histology. Results: In phantom, the myocardium contrast vs. paraffin varied from 40% at 20 kV to 29% at 50 kV. The fat contrast vs. background was 2% at 20 kV, whereas it was indistinguishable from the background at 50 kV; all the contrasts in phantom appeared lower than those expected from simulations, probably because of tissue shrinkage. In the samples from pig (see Figure), the vessel wall contrast was 25% greater than the myocardium contrast; the pericardium and a balloon induced stenosis were clearly distinguished. All micro CT scans were shorter than 1 hour. Conclusion: Micro CT is a useful complementary tool for the 3D morphometry of coronary vessels after paraffin embedding, and it can help for the preliminary identification of features of interest for subsequent histological analysis

Improved myocardial perfusion in chronic diabetic mice by the up-regulation of pLKB1 and AMPK signaling

Previous studies related impaired myocardial microcirculation in diabetes to oxidative stress and endothelial dysfunction. Thus, this study was aimed to determine the effect of up-regulating pAMPK-pAKT signaling on coronary microvascular reactivity in the isolated heart of diabetic mice. We measured coronary resistance in wild-type and streptozotocin (STZ)-treated mice, during perfusion pressure changes. Glucose, insulin, and adiponectin levels in plasma and superoxide formation, NOx levels and heme oxygenase (HO) activity in myocardial tissue were determined. In addition, the expression of HO-1, 3-nitrotyrosine, pLKB1, pAMPK, pAKT, and peNOS proteins in control and diabetic hearts were measured. Coronary response to changes in perfusion pressure diverged from control in a time-dependent manner following STZ administration. The responses observed at 28 weeks of diabetes (the maximum time examined) were mimicked by L-NAME administration to control animals and were associated with a decrease in serum adiponectin and myocardial pLKB1, pAMPK, pAKT, and pGSK-3 expression. Cobalt protoporphyrin treatment to induce HO-1 expression reversed the microvascular reactivity seen in diabetes towards that of controls. Up-regulation of HO-1 was associated with an increase in adiponectin, pLKB1, pAKT, pAMPK, pGSK-3, and peNOS levels and a decrease in myocardial superoxide and 3-nitrotyrosine levels. In the present study we describe the time course of microvascular functional changes during the development of diabetes and the existence of a unique relationship between the levels of serum adiponectin, pLKB1, pAKT, and pAMPK activation in diabetic hearts. The restoration of microvascular function suggests a new therapeutic approach to even advanced cardiac microvascular derangement in diabetes

The Sizes of z∼9−10z\sim9-10 Galaxies Identified in the BoRG Survey

Redshift $z=9--10$ object selection is the effective limit of Hubble Space Telescope imaging capability, even when confirmed with Spitzer. If only a few photometry data points are available, it becomes attractive to add criteria based on their morphology in these J- and H-band images. One could do so through visual inspection, a size criterion, or alternate morphometrics. We explore a vetted sample of BoRG $z\sim9$ and $z\sim10$ candidate galaxies and the object rejected by Morishita+ (2018) to explore the utility of a size criterion in z=9-10 candidate selection. A stringent, PSF-corrected effective radius criterion (r_e<0\farcs3) would result in the rejection of 65-70\% of the interlopers visually rejected by Morishita+. It may also remove up to $\sim20$\% of bona-fide brightest ($L>>L^*$) z=9 or 10 candidates from a BoRG selected sample based on the Mason+ (2015) luminosity functions, assuming the Holwerda+ (2015) $z\sim9$ size-luminosity relation. We argue that including a size constraint in lieu of a visual inspection may serve in wide-field searches for these objects in e.g. EUCLID or HST archival imaging with the understanding that some brightest ($L>>L^*$) candidates may be missed. The sizes of the candidates found by Morishita+ (2018) follow the expected size distribution of $z\sim9$ for bright galaxies, consistent with the lognormal in Shibuya+ (2015) and single objects. Two candidates show high star-formation surface density ($\Sigma_{SFR} > 25 M_\odot/kpc^2$) and all merit further investigation and follow-up observations.Comment: 9 Figures, 1 table, 13 pages, accepted for publication in The Astronomical Journa

The Influence of Body Mass Index on Survival and Length of Stay in Patients with Septic Shock

Background: Obesity is one of the most widespread epidemics of our time. In fact, currently 65.7% of US adults age 20 and older are overweight, while 30.6% are obese. It has been well-established that obesity has numerous adverse effects on long-term health, however the specific effect on patients treated for sepsis and septic shock is unclear. Body Mass Index (BMI) is a measure of total body fat content and surrogate marker for obesity. In our study, we aimed to identify if BMI was an independent risk factor for poor survival or increased length of stay (LOS) in patients with sepsis. Methods: We retrospectively selected patients with diagnostic codes of sepsis and septic shock who were admitted to the ICU over three years. These patients were further separated into groups of alive and deceased. Based on their perceived association with mortality in sepsis, numerous variables were investigated, such as BMI, LOS, age, cirrhosis, chronic kidney disease (CKD), lactate, age, multiple organ dysfunction syndrome (MODS), and APACHE II scores. Specifically, BMI was classified into sub-groups, including underweight (BMI30). The alive and deceased groups were initially compared for any significant differences with univariate analysis. Thereafter, the significant variables were analyzed using multivariate analysis to assess whether any were able to independently predict mortality in sepsis. Results: Our study selected 293 patients with sepsis, including 185 alive and 108 deceased. Interestingly, our univariate analysis revealed that underweight and obese patients exhibited slightly less mortality in sepsis compared to normal and overweight patients. However, these results did not reach statistical significance, with a p-value of 0.30; this was confirmed in multivariate analysis, which resulted in a p-value of 0.08. Additionally, underweight, overweight, and obese patients had a slightly decreased median LOS in the ICU and hospital compared to patients with normal BMI. Nevertheless, these results were not significant either, with ICU LOS p-value of 0.22 and hospital LOS p-value of 0.45. Univariate analysis identified certain variables that reached statistical significance, including cirrhosis (p2 (p=0.03), median lactate (p=0.05), age (p\u3e.01), and APACHE II scores (p\u3e0.01). Multivariate analysis of these variables established that only the presence of cirrhosis (p=0.03), age (p Conclusion: The data suggests that normal BMI in patients with sepsis may result in increased mortality and LOS both in the ICU and hospital, though this was not statistically significant. Other variables that were significant independent predictors for mortality in sepsis were cirrhosis, mean age, and mean APACHE II score. As the obesity epidemic continues to rise, further inquiry into the association of BMI and mortality in sepsis is needed

Gas embolization of the liver in a rat model of rapid decompression

Occurrence of liver gas embolism after rapid decompression was assessed in 31 female rats that were decompressed in 12 min after 42 min of compression at 7 ATA (protocol A). Sixteen rats died after decompression (group I). Of the surviving rats, seven were killed at 3 h (group II), and eight at 24 h (group III). In group I, bubbles were visible in the right heart, aortic arch, liver, and mesenteric veins and on the intestinal surface. Histology showed perilobular microcavities in sinusoids, interstitial spaces, and hepatocytes. In group II, liver gas was visible in two rats. Perilobular vacuolization and significant plasma aminotransferase increase were present. In group III, liver edema was evident at gross examination in all cases. Histology showed perilobular cell swelling, vacuolization, or hydropic degeneration. Compared with basal, enzymatic markers of liver damage increased significantly. An additional 14 rats were decompressed twice (protocol B). Overall mortality was 93%. In addition to diffuse hydropic degeneration, centrilobular necrosis was frequently observed after the second decompression. Additionally, 10 rats were exposed to three decompression sessions (protocol C) with doubled decompression time. Their mortality rate decreased to 20%, but enzymatic markers still increased in surviving rats compared with predecompression, and perilobular cell swelling and vacuolization were present in five rats. Study challenges were 1) liver is not part of the pathophysiology of decompression in the existing paradigm, and 2) although significant cellular necrosis was observed in few animals, zonal or diffuse hepatocellular damage associated with liver dysfunction was frequently demonstrated. Liver participation in human decompression sickness should be looked for and clinically evaluated