Sulfur-containing compounds (SCCs) are the most abundant heteroatom compounds in petroleum. The characterization of SCCs in crude oils and petroleum products has great importance not only for the ...downstream refining process control/optimization and environmental compliance but also for upstream geochemical studies for exploration and production. In recent years, a variety of methods to analyze SCCs have been developed and practiced where chromatography and mass spectrometry have played major roles. This review summarizes the analytical strategy and some of the most important and promising technologies, from sample pretreatment to molecular level characterization. For the convenience of discussions and practical applications, we divide the petroleum mixtures containing sulfur components into gas chromatography (GC)-amenable and nonvolatile fractions. For the former, gas chromatography (GC) and comprehensive two-dimensional gas chromatography (GC × GC) utilizing sulfur-selective detectors or mass spectrometry (GC–MS) are predominant analytical techniques. For the latter, molecular characterization is much more difficult and challenging. High performance liquid chromatography (HPLC) or direct liquid infusion and its combination with mass spectrometry (LC–MS), especially ultra-high resolution mass spectrometry, such as Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and Orbitrap MS, associated with various atmospheric ionization techniques are the most practical approaches. Some ionization techniques are underutilized, such as atmospheric pressure chemical ionization (APCI). The use of surface desorption ionization techniques, direct electrospray ionization (DSEI) and desorption atmospheric chemical ionization (DAPCI), for the molecular characterization of insoluble kerogens that has been characterized by X-ray near edge structure spectroscopy (XANES) and X-ray photoelectron spectroscopy (XPS) remain to be explored.
Fluid catalytic cracking (FCC) is the workhorse of modern crude oil refinery. Its regenerator plays a critical role in optimizing the overall profitability by efficiently restoring the catalyst ...activity and enhancing the heat balance in the riser reactor. Improvement in the device metallurgy and process operations have enabled industrial regenerators to operate at high temperatures with a better coke burning rate and longer operating cycle. Today, the carbon content of regenerated catalyst has drastically reduced to less than 0.1 wt.%. However, the unit is still plagued with operational complexities and insufficient understanding of the underlying dynamic, multiscale intricacies. Recent process-intensification strategies provide insights into regenerator performance improvement potentials. In this review, the importance of the uniform distribution of spent catalysts through structural modification and operational manipulations of the catalyst distributor is discussed. The knowledge of the role of baffles in enhancing excellent gas–solid interaction has been increasing, but skepticism due to its complex hydrodynamic effects on gas–solid flows fends off operators from its application, a critical evaluation of its implication in the regenerators is covered. The understanding of the contribution of air/steam distributor design and feed gas injection techniques for even contact with spent catalyst leading to the improvement in FCC performance is also investigated. The reliability of FCC components is equally a big concern, as unplanned shutdown and enormous economic losses are being witnessed due to device failure. To this end, mitigation approaches to damaging afterburn and high-temperature erosion problems with respect to process control and geometric adjustment in the bed, freeboard, cyclone separators and collection ducts are explored. Emission limits for fluid catalytic cracking unit (FCCU) and products are consistently ratcheting downward; the commingled turnkey solutions to reducing pollutants generation are also reviewed.
The response to acute and long-term arginine starvation results in a conditional adaptive metabolic reprogramming that can be harnessed for therapeutic opportunities in ASS1-negative tumors. Here, we ...investigate the underlying biology of priming ASS1
tumors with arginine deiminase (ADI-PEG20) before treatment with gemcitabine (GEM) and docetaxel (DTX) in sarcoma, pancreatic cancer, and melanoma cell lines.
ASS1
tumor cell lines were treated to create LTAT (long-term ADI treated) cell lines (ASS1
) and used for drug combination studies. Protein expression of ASS1, dCK, RRM2, E2F1, c-MYC, and hENT1 was measured. c-MYC activity was determined, live-cell immunofluorescent studies for hENT1, uptake assays of FITC-cytosine probe, and rescue studies with a c-MYC inhibitor were all determined in the presence or absence of the ADI-PEG20:GEM:DTX.
In examining modulations within the pyrimidine pathway, we identified that the addition of DTX to cells treated with ADI-PEG20 resulted in translocation of stabilized c-Myc to the nucleus. This resulted in an increase of hENT1 cell-surface expression and rendered the cells susceptible to GEM.
studies demonstrate that the combination of ADI-PEG20:GEM:DTX was optimal for tumor growth inhibition, providing the preclinical mechanism and justification for the ongoing clinical trial of ADI-PEG20, GEM, and DTX in sarcoma.
The priming of tumors with ADI-PEG20 and DTX results in the stabilization of c-MYC potentiating the effect of GEM treatment via an increase in hENT1 expression. This finding is applicable to ASS1-deficient cancers that are currently treated with GEM.
To retrospectively compare the diagnostic performance of different noninvasive diagnostic criteria of HCC including LI-RADS, OPTN-UNOS, AASLD, NCCN, EASL-EORTC, KLCSG-NCC.
We reviewed the medical ...records of 3,491 pathologically examined liver lesions from January-2011 to January-2015 in our institution. 195 lesions in 133 patients (M:F = 100:33) with chronic hepatitis B/C and/or cirrhosis for any etiology were finally included in our study, with 98 lesions ≥ 2 cm, 72 lesions between 1-2 cm, and 25 lesions < 1 cm. The main comparison was made with the largest nodules of each patient (n = 133). The lesions were retrospectively evaluated for the diagnosis of HCC on DCE-CT or MR using different noninvasive diagnostic criteria including LI-RADS, OPTN-UNOS, AASLD, NCCN, EASL-EORTC, and KLCSG-NCC. With pathological evaluation serving as a gold-standard, sensitivity, specificity, PPV and NPV as well as accuracy of the diagnostic criteria were calculated.
There was no statistically significant differences in diagnostic accuracy among noninvasive diagnostic criteria. For 133 lesions of the largest lesion per patient, the overall accuracy was highest with LI-RADS criteria (89.3%) and the overall sensitivity was highest with LI-RADS, AASLD, NCCN criteria (all 89.5%). For 1-2 cm lesions, sensitivity decreased for all criteria in the following order: EASL-EORTC (59.1%), KLCSG-NCC (58.3%), LI-RADS, AASLD, NCCN (all 56.5%), and OPTN-UNOS (22.7%) criteria. OPTN-UNOS had the highest specificity in cirrhotic livers, 91.7%.
The current noninvasive diagnostic criteria of HCC have no statistically significant difference in diagnostic accuracy. Overall, LI-RADS had the highest sensitivity and accuracy among the guidelines. OPTN had the highest specificity for cirrhotic livers.
Background Lifestyle and metabolic diseases influence the severity and pathogenesis of cardiovascular disease through numerous mechanisms, including regulation via posttranslational modifications. A ...specific posttranslational modification, the addition of
-linked β-
acetylglucosamine (
-GlcNAcylation), has been implicated in molecular mechanisms of both physiological and pathologic adaptations. The current study aimed to test the hypothesis that in cardiomyocytes, sustained protein
-GlcNAcylation contributes to cardiac adaptations, and its progression to pathophysiology. Methods and Results Using a naturally occurring dominant-negative
-GlcNAcase (dnOGA) inducible cardiomyocyte-specific overexpression transgenic mouse model, we induced dnOGA in 8- to 10-week-old mouse hearts. We examined the effects of 2-week and 24-week dnOGA overexpression, which progressed to a 1.8-fold increase in protein
GlcNAcylation. Two-week increases in protein
-GlcNAc levels did not alter heart weight or function; however, 24-week increases in protein
-GlcNAcylation led to cardiac hypertrophy, mitochondrial dysfunction, fibrosis, and diastolic dysfunction. Interestingly, systolic function was maintained in 24-week dnOGA overexpression, despite several changes in gene expression associated with cardiovascular disease. Specifically, mRNA-sequencing analysis revealed several gene signatures, including reduction of mitochondrial oxidative phosphorylation, fatty acid, and glucose metabolism pathways, and antioxidant response pathways after 24-week dnOGA overexpression. Conclusions This study indicates that moderate increases in cardiomyocyte protein
-GlcNAcylation leads to a differential response with an initial reduction of metabolic pathways (2-week), which leads to cardiac remodeling (24-week). Moreover, the mouse model showed evidence of diastolic dysfunction consistent with a heart failure with preserved ejection fraction. These findings provide insight into the adaptive versus maladaptive responses to increased
GlcNAcylation in heart.
Over the years, culturable cellulase-producing microorganisms have been isolated from a variety of sources and genes of cellulolytic enzymes have been cloned. Then again, the “great plate count ...anomaly” phenomenon necessitates a culture-independent metagenomic approach for the isolation of cellulolytic genes from microorganisms in their natural environment. We have constructed a metagenomic library derived from rice straw composts. Of 2739 clones screened, a lambda clone carrying a 12kb genomic fragment was able to yield a clear zone on an agar plate containing carboxymethyl cellulose (CMC). A 4.7kb subclone, generated by restriction enzyme digestion, was found to harbor a GH12 cellulase gene, RSC-EG1, encoding 464 amino acids along with two other ORFs. The identified cellulolytic gene showed more than 70% similarity on the amino acid level with cellulase from Micromonospora aurantiaca and Thermobispora sp. Interestingly, RSC-EG1 contains a stretch of approximately 86 amino acids not present in either of these close relatives. Our results demonstrated that RSC-EG1, stable over a wide temperature and pH range, is a novel endoglucanase, and provided the first example of metagenomics approach to isolate cellulolytic gene from rice straw composts.
► A novel endoglucanase gene was cloned from DNA isolated from rice straw compost. ► Less than 3000 clones were screened to isolate the RS-EG1 endoglucanase gene. ► RS-EG1 shares about 70% similarity with the closest known bacterial cellulases. ► RS-EG1 is stable over broad temperature and pH ranges. ► RS-EG1 is potentially useful in cellulosic biofuel production.
•Carbon dioxide-based supercritical fluid extraction (CO2 SFE) was used to extract petroleum.•Compositional recovery and selectivity by different extraction methods were studied by SIMDIS, GC–MS and ...FT-ICR MS.•Most of CO2 SFE non-extractable components are not suitable for GC analysis.•CO2 SFE can be an alternative to Soxhlet solvent extraction for petroleum compositional analysis by GC–MS.
Carbon dioxide-based supercritical fluid extraction (CO2 SFE) has been an excellent alternative to solvent extraction in many industries. In this study, a heavy crude oil was adsorbed to kieselguhr and performed for comparison of different extraction processes. The oil extract by dichloromethane Soxhlet extraction was used as a benchmark. Another batch of the sample was subjected to sequential short-time and longer-time CO2 SFE, and subsequent dichloromethane Soxhlet extraction, yielding three distinct extracts. All of these four extracts were then fractionated by a standard saturates/aromatics/resin/asphaltene (SARA) method. Each SARA fraction was then analyzed by high temperature gas chromatography simulated distillation (SIMDIS), gas chromatography–mass spectrometry (GC–MS) and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). It was found that CO2 SFE selectively extracts relatively low molecular weight compounds with low degrees of molecular condensation. The remaining un-extracted components are mainly in polar resin and asphaltene fractions, containing the chemical species with large carbon numbers and high degrees of molecular condensation. Most of these components are in low volatility with boiling points higher than 500°C, beyond the upper temperature limit of common GC columns. CO2 SFE can serve as an environmental-friendly alternative to Soxhlet solvent extraction if the goal of the analysis is to determine petroleum biomarker or compositional analysis by GC–MS. In addition, CO2 SFE for extracts only volatile compounds of small molecular weight has an advantage of leaving most non-volatile components that would be detrimental to the GC systems.
Management of urinary tract infection (UTI) in postmenopausal women can be challenging. The recent rise in resistance to most of the available oral antibiotic options together with high recurrence ...rate in postmenopausal women has further complicated treatment of UTI. As such, intravesical instillations of antibiotics like gentamicin are being investigated as an alternative to oral antibiotic therapies. This study evaluates the efficacy of the candidate intravesical therapeutic VesiX, a solution containing the cationic detergent Cetylpyridinium chloride, against a broad range of uropathogenic bacterial species clinically isolated from postmenopausal women with recurrent UTI (rUTI). We also evaluate the cytotoxicity of VesiX against cultured bladder epithelial cells and find that low concentrations of 0.0063% and 0.0125% provide significant bactericidal effect toward diverse bacterial species including uropathogenic
(UPEC),
,
,
, and
while minimizing cytotoxic effects against cultured 5637 bladder epithelial cells. Lastly, to begin to evaluate the potential utility of using VesiX in combination therapy with existing intravesical therapies for rUTI, we investigate the combined effects of VesiX and the intravesical antibiotic gentamicin. We find that VesiX and gentamicin are not antagonistic and are able to reduce levels of intracellular UPEC in cultured bladder epithelial cells.
When urinary tract infections (UTIs), which affect over 50% of women, become resistant to available antibiotic therapies dangerous complications like kidney infection and lethal sepsis can occur. New therapeutic paradigms are needed to expand our arsenal against these difficult to manage infections. Our study investigates VesiX, a Cetylpyridinium chloride (CPC)-based therapeutic, as a candidate broad-spectrum antimicrobial agent for use in bladder instillation therapy for antibiotic-resistant UTI. CPC is a cationic surfactant that is FDA-approved for use in mouthwashes and is used as a food additive but has not been extensively evaluated as a UTI therapeutic. Our study is the first to investigate its rapid bactericidal kinetics against diverse uropathogenic bacterial species isolated from postmenopausal women with recurrent UTI and host cytotoxicity. We also report that together with the FDA-approved bladder-instillation agent gentamicin, VesiX was able to significantly reduce intracellular populations of uropathogenic bacteria in cultured bladder epithelial cells.
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