Publications by authors named "Oscar Chen"

We have developed two series of amine-functionalized zirconium (Zr) metal-organic framework-808 (MOF-808), which were produced by postsynthetic modifications to have either amino acids coordinated to Zr ions (MOF-808-AAs) or polyamines covalently bound to the chloro-functionalized structure (MOF-808-PAs). These MOF variants were comprehensively characterized by liquid-state H nuclear magnetic resonance (NMR) measurements and potentiometric acid-base titration to determine the amounts of amines, energy-dispersive X-ray spectroscopy to assess the extent of covalent substitution by polyamines, powder X-ray diffraction analysis to verify the maintenance of the MOF crystallinity and structure after postsynthetic modifications, nitrogen sorption isotherm measurements to confirm retention of the porosity, and water sorption isotherm measurements to find the water uptake in the pores of each member of the series. Evaluation and testing of these compounds in direct air capture (DAC) of CO showed improved CO capture performance for the functionalized forms, especially under humid conditions: In dry conditions, the l-lysine- and tris(3-aminopropyl)amine-functionalized variants, termed as MOF-808-Lys and MOF-808-TAPA, exhibited the highest CO uptakes at 400 ppm, measuring 0.

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Pulmonary artery hypertension (PAH) is characterized by vasoconstriction and vascular remodeling resulting in both increased pulmonary vascular resistance (PVR) and pulmonary artery pressure (PAP). The chronic and high-pressure stress experienced by endothelial cells can give rise to inflammation, oxidative stress, and infiltration by immune cells. However, there is no clearly defined mechanism for PAH and available treatment options only provide limited symptomatic relief.

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Article Synopsis
  • Pulmonary and systemic hypertension involve increased blood pressure due to vasoconstriction and vascular changes, leading to inflammation and stress in the body.
  • The review covers the underlying causes of pulmonary hypertension (PH), looking at oxidative stress, immune response, mitochondrial issues, and right ventricular dysfunction.
  • It also discusses the potential role of metals in PH, suggesting that both essential and non-essential metals could impact vascular health, prompting the need for further research to clarify their effects and develop new treatments.
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: Niemann-Pick disease type C1 (NPC1) is a neurodegenerative lysosomal storage disorder characterized by the accumulation of multiple lipids in the late endosome/lysosomal system and reduced acidic store calcium. The lysosomal system regulates key aspects of iron homeostasis, which prompted us to investigate whether there are hematological abnormalities and iron metabolism defects in NPC1. : Iron-related hematological parameters, systemic and tissue metal ion and relevant hormonal and proteins levels, expression of specific pro-inflammatory mediators and erythrophagocytosis were evaluated in an authentic mouse model and in a large cohort of NPC patients.

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Endothelial progenitor cells (EPCs) are reduced in number and impaired in function in diabetic patients. Whether and how Nrf2 regulates the function of diabetic EPCs remains unclear. In this study, we found that the expression of Nrf2 and its downstream genes were decreased in EPCs from both diabetic patients and db/db mice.

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Neutrophils play a significant role in determining disease severity following SARS-CoV-2 infection. Gene and protein expression defines several neutrophil clusters in COVID-19, including the emergence of low density neutrophils (LDN) that are associated with severe disease. The functional capabilities of these neutrophil clusters and correlation with gene and protein expression are unknown.

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Purpose: Endothelial progenitor cells (EPCs) play a critical role in repairing damaged vessels and triggering ischemic angiogenesis, but their number is reduced and function is impaired under diabetic conditions. Improving EPC function has been considered a promising strategy to ameliorate diabetic vascular complications. In the present study, we aim to investigate whether and how CXCR7 agonist TC14012 promotes the angiogenic function of diabetic EPCs.

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Elderly adults are at higher risk for developing diabetic complications including diabetic nephropathy (DN), contributing to excess morbidity and mortality in elderly individuals. A non-mitogenic variant of fibroblast growth factor 1 (FGF1) was demonstrated to prevent DN in an early-stage (2-month-old) type 2 diabetes (T2D) mouse model. The present study aimed to investigate the potential therapeutic effects of FGF1 against the progression of renal dysfunction in a late-stage T2D mouse model with established DN.

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Metal-organic framework-808 has been functionalized with 11 amino acids (AA) to produce a series of MOF-808-AA structures. The adsorption of CO under flue gas conditions revealed that glycine- and dl-lysine-functionalized MOF-808 (MOF-808-Gly and -dl-Lys) have the highest uptake capacities. Enhanced CO capture performance in the presence of water was observed and studied by using single-component sorption isotherms, CO/HO binary isotherm, and dynamic breakthrough measurements.

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SARS coronavirus 2 (SARS-CoV-2) is a novel viral pathogen that causes a clinical disease called coronavirus disease 2019 (COVID-19). Although most COVID-19 cases are asymptomatic or involve mild upper respiratory tract symptoms, a significant number of patients develop severe or critical disease. Patients with severe COVID-19 commonly present with viral pneumonia that may progress to life-threatening acute respiratory distress syndrome (ARDS).

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Niemann-Pick disease type C (NPC) is a neurodegenerative lysosomal storage disorder caused by mutations in either (95% of cases) or . Reduced late endosome/lysosome calcium (Ca) levels and the accumulation of unesterified cholesterol and sphingolipids within the late endocytic system characterize this disease. We previously reported impaired lysosome-related organelle (LRO) function in Natural Killer cells; however, the potential contribution of impaired acid compartment Ca flux and LRO function in other cell types has not been determined.

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Study Design: This was a narrative review.

Objective: This study aimed to review the current literature on surgical simulation in orthopedics and its application to spine surgery.

Summary Of Background Data: As orthopedic surgery increases in complexity, training becomes more relevant.

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Targeted agents have improved the efficacy of chemotherapy for cancer patients, however, there remains a lack of understanding of how these therapies affect the unsuspecting bystanders of the stromal microenvironment. Cetuximab, a monoclonal antibody therapy targeting the epidermal growth factor receptor (EGFR), is given in combination with chemotherapy as the standard of care for a subset of metastatic colorectal cancer patients. The overall response to this treatment is underwhelming and, while genetic mutations that confer resistance have been identified, it is still not known why this drug is ineffective for some patients.

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Study Design: Retrospective cohort study.

Objective: To assess the effect of diabetes mellitus (DM) on clinical and radiographic outcomes in patient with degenerative spondylolisthesis undergoing posterior lumbar spinal fusion.

Methods: Analysis of patients who underwent open posterior lumbar spinal fusion from 2011 to 2018.

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Niemann-Pick C disease (NPC) is an autosomal recessive lysosomal storage disorder resulting from mutations in the NPC1 (95% of cases) or NPC2 genes. Disturbance of copper homeostasis has been reported in NPC1 disease. In this study we have used whole-body positron emission tomography (PET) and brain electronic autoradiography with copper-64 (Cu), in the form of the copper(II) bis(thiosemicarbazonato) complex Cu-GTSM, to image short-term changes in copper trafficking after intravenous injection in a transgenic mouse model of NPC1 disease.

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Niemann-Pick C disease (NPC) is a vesicular trafficking disorder primarily caused by mutations in the Npc1 gene and characterized by liver dysfunction and neuropathology. Altered hepatic copper metabolism has recently been reported in NPC disease. Therefore, we aimed to analyze the effects of a copper deficient diet and copper chelation using d-penicillamine on copper homeostasis in the liver of Npc1(-/-) mice of different ages.

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The endoplasmic reticulum (ER) is a large, multifunctional and essential organelle. Despite intense research, the function of more than a third of ER proteins remains unknown even in the well-studied model organism Saccharomyces cerevisiae. One such protein is Spf1, which is a highly conserved, ER localized, putative P-type ATPase.

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