Studies of ice formation behaviors of upper tropospheric aerosol and their chemical compositions by continuous flow thermal diffusion chamber

October 1999.Also issued as author's dissertation (Ph.D.) -- Colorado State University, 1999.Includes bibliographical references.Studies were conducted to investigate ice formation by aerosol particles at upper tropospheric conditions. The continuous flow thermal diffusion chamber ( CFD) was used in both field and lab experiments to determine the conditions for the onset of ice formation in ambient and lab aerosols. After confirming the capability of the CFD to separate ice nucleating particles (IN) from non-IN, we collected samples of both IN and non-IN from the upper troposphere (UT) and the lower stratosphere during the 1996 NASA SUCCESS airborne field campaign. The chemical compositions of these particles were measured by electron microscopy, an individual particle analysis technique. From these results, as well as previous studies, ammoniated sulfates, sulfuric acid, and soot particles with different coatings were selected as representative UT aerosols for further laboratory investigation of their ice formation behaviors. In controlled laboratory studies, the phase states of (NH4)2SO4 and NH4HSO4 particles were found to have important impacts on their ice formation capabilities. Dry (NH4)2SO4 particles nucleated ice only at high relative humidity with respect to water at temperatures between -40°C and -60°C. Ammonium sulfate particles that entered the diffusion chamber in a liquid state froze by homogenous freezing at relative humidities that were 10% lower than where ice nucleated on dry particles. Likewise, crystalline or partially crystallized (as letovicite) NH4HSO 4 particles required higher relative humidities for ice nucleation than did initially liquid bisulfate particles . Based on our observations, 0.2 μm particles composed of either ammonium sulfate or bisulfate in a liquid solution freeze at lower RH at UT temperatures than do 0.05 μm sulfuric acid aerosol particles. The results indicate that, for liquid droplets, the size effect may be more important than the degree of ammoniation of the sulfate compound. Soot particles with different coating treatments were investigated in a similar manner as the sulfates. Submicron particles of commercial soot were coated with H2S04 in amounts of zero to several percent by weight. Untreated soot particles showed activity as deposition/sorption ice nuclei; and soot particles with approximately one monolayer equivalent coating of sulfuric acid froze at humidities slightly higher than those of untreated soot. These observations suggest that dilution of sulfuric acid was required before homogeneous freezing. Heterogeneous freezing was observed on particles with multilayer coverage at cold temperatures (< -53°C). We also generated soot particles by combustion of jet fuels and examined the freezing behavior of 0.05 μm monodisperse particles. The jet fuel soot particles contain about 10% by weight soluble matter, and did not freeze below 95% RH. Similarities existed in the ice formation behaviors of these jet fuel soot particles and 0.016 μm pure sulfuric acid particles. These laboratory results suggest that small solution droplets, with diameters of several hundredths of microns, require relatively high humidity to freeze homogeneously, and are therefore unlikely to be the particles that form cirrus clouds with continental origins. Dry crystals of sulfate form ice near water saturation. Sulfuric acid coating changes the ice formation properties of soot particles dramatically. With multilayer sulfuric acid coating, soot particles initiate homogeneous freezing at cirrus cloud conditions at cold temperatures. This suggests a heterogeneous nucleation pathway for continental cirrus formation. Pure soot particles and those with a small amount of sulfuric acid coating, like fresh aircraft exhaust, only form contrails near water saturation.Sponsored by the National Science Foundation ATM 93-11606 and ATM 96-32917; the National Aeronautics and Space Administration NAG-2-924; and NASA Earth System Science Fellowship NGT5-30001

Function modification of SR-PSOX by point mutations of basic amino acids

<p>Abstract</p> <p>Background</p> <p>Atherosclerosis (AS) is a common cardiovascular disease. Transformation of macrophages to form foam cells by internalizing modified low density-lipoprotein (LDL) via scavenger receptor (SR) is a key pathogenic process in the onset of AS. It has been demonstrated that SR-PSOX functions as either a scavenger receptor for uptake of atherogenic lipoproteins and bacteria or a membrane-anchored chemokine for adhesion of macrophages and T-cells to the endothelium. Therefore, SR-PSOX plays an important role in the development of AS. In this study the key basic amino acids in the chemokine domain of SR-PSOX have been identified for its functions.</p> <p>Results</p> <p>A cell model to study the functions of SR-PSOX was successfully established. Based on the cell model, a series of mutants of human SR-PSOX were constructed by replacing the single basic amino acid residue in the non-conservative region of the chemokine domain (arginine 62, arginine 78, histidine 80, arginine 82, histidine 85, lysine 105, lysine 119, histidine 123) with alanine (designated as R62A, R78A, H80A, R82A, H85A, K105A, K119A and H123A, respectively). Functional studies showed that the mutants with H80A, H85A, and K105A significantly increased the activities of oxLDL uptake and bacterial phagocytosis compared with the wild-type SR-PSOX. In addition, we have also found that mutagenesis of either of those amino acids strongly reduced the adhesive activity of SR-PSOX by using a highly non-overlapping set of basic amino acid residues.</p> <p>Conclusion</p> <p>Our study demonstrates that basic amino acid residues in the non-conservative region of the chemokine domain of SR-PSOX are critical for its functions. Mutation of H80, H85, and K105 is responsible for increasing SR-PSOX binding with oxLDL and bacteria. All the basic amino acids in this region are important in the cells adhesion via SR-PSOX. These findings suggest that mutagenesis of the basic amino acids in the chemokine domain of SR-PSOX may contribute to atherogenesis.</p

The Optimization of Jaw Crusher with Complex Motion Aimed at Reducing Stroke Feature Value of Its Outlet

Volume 8 Issue 1 (January 201

Measuring case severity: a novel tool for benchmarking and clinical documentation improvement

BACKGROUND: Severity of illness (SOI) is an All Patients Refined Diagnosis Related Groups (APR DRG) modifier based on comorbidity capture. Tracking SOI helps hospitals improve performance and resource distribution. Furthermore, benchmarking SOI plays a key role in Quality Improvement (QI) efforts such as Clinical Documentation Improvement (CDI) programs. The current SOI system highly relies on the 3 M APR DRG grouper that is updated annually, making it difficult to track severity longitudinally and benchmark against hospitals with different patient populations. Here, we describe an alternative SOI scoring system that is grouper-independent and that can be tracked longitudinally. METHODS: Admission data for 2019-2020 U.S. News and World Report Honor Roll facilities were downloaded from the Vizient Clinical Database and split into training and testing datasets. Elixhauser comorbidities, body systems developed from the Healthcare Cost and Utilization Project (HCUP), and ICD-10-CM complication and comorbidity (CC/MCC) indicators were selected as the predictors for orthogonal polynomial regression models to predict patients\u27 admission and discharge SOI. Receiver operating characteristic (ROC) and Precision-Recall (PR) analysis, and prediction accuracy were used to evaluate model performance. RESULTS: In the training dataset, the full model including both Elixhauser comorbidities and body system CC/MCC indicators had the highest ROC AUC, PR AUC and predication accuracy for both admission (ROC AUC: 92.9%; PR AUC: 91.0%; prediction accuracy: 85.4%) and discharge SOI (ROC AUC: 93.6%; PR AUC: 92.8%; prediction accuracy: 86.2%). The model including only body system CC/MCC indicators had similar performance for admission (ROC AUC: 92.4%; PR AUC: 90.4%; prediction accuracy: 84.8%) and discharge SOI (ROC AUC: 93.1%; PR AUC: 92.2%; prediction accuracy: 85.6%) as the full model. The model including only Elixhauser comorbidities exhibited the lowest performance. Similarly, in the validation dataset, the prediction accuracy was 86.2% for the full model, 85.6% for the body system model, and 79.3% for the comorbidity model. With fewer variables and less model complexity, the body system model was more efficient and was determined to be the optimal model. The probabilities generated from this model, named J_Score and J_Score_POA, successfully measured SOI and had practical applications in assessment of CDI performance. CONCLUSIONS: The J_Scores generated from the body system model have significant value in evaluating admission and discharge severity of illness. We believe that this new scoring system will provide a useful tool for healthcare institutions to benchmark patients\u27 illness severity and augment Quality Improvement (QI) efforts

Identification and validation of the diagnostic signature associated with immune microenvironment of acute kidney injury based on ferroptosis-related genes through integrated bioinformatics analysis and machine learning

Background: Acute kidney injury (AKI) is a common and severe disease, which poses a global health burden with high morbidity and mortality. In recent years, ferroptosis has been recognized as being deeply related to Acute kidney injury. Our aim is to develop a diagnostic signature for Acute kidney injury based on ferroptosis-related genes (FRGs) through integrated bioinformatics analysis and machine learning.Methods: Our previously uploaded mouse Acute kidney injury dataset GSE192883 and another dataset, GSE153625, were downloaded to identify commonly expressed differentially expressed genes (coDEGs) through bioinformatic analysis. The FRGs were then overlapped with the coDEGs to identify differentially expressed FRGs (deFRGs). Immune cell infiltration was used to investigate immune cell dysregulation in Acute kidney injury. Functional enrichment analysis and protein-protein interaction network analysis were applied to identify candidate hub genes for Acute kidney injury. Then, receiver operator characteristic curve analysis and machine learning analysis (Lasso) were used to screen for diagnostic markers in two human datasets. Finally, these potential biomarkers were validated by quantitative real-time PCR in an Acute kidney injury model and across multiple datasets.Results: A total of 885 coDEGs and 33 deFRGs were commonly identified as differentially expressed in both GSE192883 and GSE153625 datasets. In cluster 1 of the coDEGs PPI network, we found a group of 20 genes clustered together with deFRGs, resulting in a total of 48 upregulated hub genes being identified. After ROC analysis, we discovered that 25 hub genes had an area under the curve (AUC) greater than 0.7; Lcn2, Plin2, and Atf3 all had AUCs over than this threshold in both human datasets GSE217427 and GSE139061. Through Lasso analysis, four hub genes (Lcn2, Atf3, Pir, and Mcm3) were screened for building a nomogram and evaluating diagnostic value. Finally, the expression of these four genes was validated in Acute kidney injury datasets and laboratory investigations, revealing that they may serve as ideal ferroptosis markers for Acute kidney injury.Conclusion: Four hub genes (Lcn2, Atf3, Pir, and Mcm3) were identified. After verification, the signature’s versatility was confirmed and a nomogram model based on these four genes effectively distinguished Acute kidney injury samples. Our findings provide critical insight into the progression of Acute kidney injury and can guide individualized diagnosis and treatment

Proteomic Profiles of Exosomes of Septic Patients Presenting to the Emergency Department Compared to Healthy Controls

BACKGROUND: Septic Emergency Department (ED) patients provide a unique opportunity to investigate early sepsis. Recent work focuses on exosomes, nanoparticle-sized lipid vesicles (30-130 nm) that are released into the bloodstream to transfer its contents (RNA, miRNA, DNA, protein) to other cells. Little is known about how early changes related to exosomes may contribute to the dysregulated inflammatory septic response that leads to multi-organ dysfunction. We aimed to evaluate proteomic profiles of plasma derived exosomes obtained from septic ED patients and healthy controls. METHODS: This is a prospective observational pilot study evaluating a plasma proteomic exosome profile at an urban tertiary care hospital ED using a single venipuncture blood draw, collecting 40 cc Ethylenediaminetetraacetic acid (EDTA) blood. MEASUREMENTS: We recruited seven patients in the ED within 6 h of their presentation and five healthy controls. Plasma exosomes were isolated using the Invitrogen Total Exosome Isolation Kit. Exosome proteomic profiles were analyzed using fusion mass spectroscopy and Proteome Discoverer. Principal component analysis (PCA) and differential expression analysis (DEA) for sepsis versus control was performed. RESULTS: PCA of 261 proteins demonstrated septic patients and healthy controls were distributed in two groups. DEA revealed that 62 (23.8%) proteins differed between the exosomes of septic patients and healthy controls, CONCLUSION: Exosome proteomic profiles of septic ED patients differ from their healthy counterparts with regard to acute phase response and inflammation

Patient and disease pre-operative factors influencing surgical procedure choice for breast cancer treatment

Background/Objective: To address disparities of care in breast cancer treatment, it is important to understand pre‐operative factors that could affect the surgical decision‐making process. Methods: This prospective cohort study evaluates patient‐reported outcomes in women undergoing breast cancer treatment at a metropolitan health care system. Each new breast cancer case undergoes tumor board discussion, and patients have same‐day consultations with various specialties. Based on their procedure choice, women choose to complete pre‐ and post‐operative Breast‐Q© Breast‐ conserving Surgery (BCS), Mastectomy (M), or Reconstruction ® modules and demographic surveys. Individual effects of pre‐operative factors on procedure choice were assessed using ANOVA for continuous variables and chi‐squared for categorical. Significant factors (p≤0.05) were added to a multinomial logistic regression model. Results: A total of 375 women completed pre‐operative surveys (BCS=244, M=39, BR=92). Compared to BR, those chose BCS were older (RRR=1.094, p\u3c0.001) with larger BMIs (RRR=1.094, p=0.001), without a history of breast cancer (RRR=0.130 (yes vs. no), p=0.016), and Stage I disease (RRR=4.920, p\u3c0.001). Women making more than $200K (RRR=4.56x105 (vs. 35K), p\u3c0.0001) were also more likely to undergo BR. Compared to BCS, women undergoing neoadjuvant chemotherapy (RRR=3.591, p=0.047) and Stage II disease (RRR=4.238, p=0.040) were more likely to undergo mastectomy alone, whereas race, education, employment, and most incomes did not correlate with procedure choice. Conclusions: Our data suggest that racial and socioeconomic disparities in procedure type can be addressed by presenting equally effective surgical strategies to all patients in a multidisciplinary model that allows patients to interact with plastic surgeons, radiation oncologists, and surgical and medical oncologists