Serum magnesium level and cardiac valve calcification in hemodialysis patients.

INTRODUCTION: Cardiac valve calcification is closely related to cardiovascular disease. The aim of this study was to investigate the magnesium level and cardiac valve calcification in hemodialysis patients. METHODS: A cross-sectional study was conducted in 105 maintenance hemodialysis patients with complete follow-up data from June 2020 to May 2021 in Beijing Tsinghua Changgung Hospital, Tsinghua University. Baseline data, including sex, age, primary disease, liver and kidney function, electrolytes and parathyroid hormone, were recorded. According to their echocardiograms, patients were divided into a cardiac valve calcification group and a noncardiac valve calcification group, and the correlations between valve calcification and clinical data were analyzed. RESULTS: Of 105 patients under hemodialysis, 60 (56.6%) were male, with an average age of 62.1 ± 13.5 years and a mean dialysis duration of 58.8 ± 45.4 months. The majority of primary renal diseases were diabetic nephropathy (55, 51.9%). Approximately 64.8% of the 105 maintenance hemodialysis patients had cardiac valve calcification, and 35.2% were in the noncardiac valve calcification group. The independent t test and the chi-square test analysis showed that the cardiac valve calcification group had older age, higher smoking rate, diabetes mellitus, lower extremity arterial occlusion, coronary heart disease, and coronary artery calcification ratio but lower parathyroid hormone, serum calcium, serum magnesium, albumin, prealbumin, and high-density lipoprotein cholesterol levels (P < 0.05). Logistic regression analysis showed that age, diabetes mellitus, coronary artery calcification, lower serum magnesium, lower serum calcium, and lower parathyroid hormone levels were associated with valve calcification. CONCLUSION: The presence of cardiac valve calcification was associated with age, calcium, phosphorus and lower magnesium level. These factors we should pay more attention in clinical practice.

Emission characteristics of a diesel engine fueled with nanoemulsions of continuous diesel dispersed with solketal droplets.

Solketal is a promising oxygenate additive that can be chemically derived from bioglycerol. Emulsification by a microwave-irradiating method was used to prepare the micro- and nanoemulsions of solketal dispersed in continuous ultra-low sulfur diesel (ULSD) due to the immiscibility of solketal with ULSD. The emissions from a direct-injection, four-stroke and naturally aspirated diesel engine fueled with each of these emulsions, and with neat ULSD, were analyzed and compared. The experimental results show that the nanoemulsion and microemulsions were successfully produced. In addition, an increasing engine speed resulted in lower NOx, CO and O2 but higher CO2 emissions. The nanoemulsion was found to produce the lowest NOx emission while neat ULSD produced the highest NOx emission among these three test fuels. The lowest CO emission was formed by fueling the micro-emulsion of dispersed solketal-in-ULSD. Moreover, the burning of the nanoemulsion in the diesel engine formed the highest CO2 along with the lowest O2 emissions. Hence, the nanoemulsion had the highest burning efficiency among the three test fuels for the diesel engine.

Abdominal aortic calcification is superior to other arteries calcification in predicting the mortality in peritoneal dialysis patients - a 8 years cohort study.

BACKGROUND: In recent years, there has been a growing concern that abdominal aortic calcification (AAC) has a predictive effect on the prognosis of patients with end-stage renal disease (ESRD). However, whether other vascular calcification (VC) can predict the occurrence of adverse events in patients, and whether it is necessary to assess the calcification of other blood vessels remains controversial. This study aimed to assess VC in different sites using X-ray films, and to investigate the predictive effects of VC at different sites on all-cause mortality and cardiovascular (CV) mortality in peritoneal dialysis (PD) patients. METHODS: The data of Radiographs (lateral abdominal plain film, frontal pelvic radiograph and both hands radiograph) were collected to evaluate the calcification of abdominal aorta, iliac artery, femoral artery, radial artery, and finger arteries. Patients' demographic data, clinical characteristics, laboratory data were recorded. The total follow-up period was 8 years, and the time and cause of death were recorded. Survival curves were estimated using Kaplan-Meier analysis. COX regression analysis was used to examine independent predictors of all-cause mortality and CV mortality. RESULTS: One hundred fifty PD patients were included, a total of 79 patients (52.7%) died at the end of follow-up. After adjusting variables in the multivariate COX regression analysis, AAC was an independent predictor of all-cause mortality in PD patients (HR = 2.089, 95% CI: 1.089-4.042, P = 0.029), and was also an independent predictor of CV mortality (HR = 4.660, 95% CI: 1.852-11.725, P = 0.001). We also found that femoral artery calcification had a predictive effect on all-cause and CV mortality. But the calcification in iliac artery, radial artery, and finger arteries were not independent predictors of patients' all-cause and CV mortality in PD patients. CONCLUSION: AAC was more common in PD patients and was an independent predictor of all-cause mortality and CV mortality. The femoral artery calcification also can predict the mortality, but the calcification of iliac artery, radial artery, and finger arteries cannot predict the mortality of PD patients.

Comparison of Engine Performance between Nano- and Microemulsions of Solketal Droplets Dispersed in Diesel Assisted by Microwave Irradiation.

As a derivative product of bio-glycerol, this study first uses solketal as a combustion improver for enhancing diesel engine characteristics. The emulsions of nanometer- and micrometer-sized droplets of solketal, which disperse evenly in the ultra-low sulfur diesel (ULSD), are formed by the effects of microwave irradiation. The performance of diesel engine fueled with the nanoemulsion of ULSD with scattered solketal droplets is analyzed and compared to that with the microemulsion. The experimental results show that the nanoemulsions can form when over 15 wt. % surfactant mixtures of Span 80 and Tween 80 and less than 5 wt. % solketal are mixed and emulsified with the remaining ULSD content, which acts as the continuous phase of the emulsions. The nanoemulsions are observed to have significantly lower brake-specific fuel consumption (bsfc) and higher fuel conversion efficiency and exhaust gas temperature than those of the microemulsions and the neat ULSD. However, the bsfc of the nanoemulsions increases with greater engine speed and gradually approaches those of the latter two test fuels. In addition, the dispersed solketal droplet sizes are mostly concentrated around 127 nm with peak intensity of 12.65% in the nanoemulsions. The microwave-assisted formation used in this study is found to successfully produce the nanoemulsions in which all of the dispersed droplet sizes are much smaller than 1000 nm.

Role of Polysaccharides in Diatom Thalassiosira pseudonana and its Associated Bacteria in Hydrocarbon Presence.

Diatoms secrete a significant amount of polysaccharides, which can serve as a critical organic carbon source for bacteria. The 2010 Deepwater Horizon oil spill exposed the Gulf of Mexico to substantial amounts of oil that also impacted the phytoplankton community. Increased production of exopolymeric substances was observed after this oil spill. Polysaccharides make up a major fraction of exopolymeric substances; however, their physiological role during an oil spill remains poorly understood. Here, we analyzed the role of polysaccharides in the growth and physiology of the oil-sensitive diatom Thalassiosira pseudonana and how they shape the surrounding bacterial community and its activity in the presence of oil. We found that inhibition of chrysolaminarin synthesis had a negative effect on the growth of T pseudonana and intracellular monosaccharide accumulation, which in turn suppressed photosynthesis by feedback inhibition. In addition, by acting as a carbon reserve, chrysolaminarin helped in the recovery of T pseudonana in the presence of oil. Inhibition of chrysolaminarin synthesis also influenced the bacterial community in the free-living fraction but not in the phycosphere. Exposure to oil alone led to increased abundance of oil-degrading bacterial genera and the activity of exoenzyme lipase. Our data show that chrysolaminarin synthesis plays an important role in the growth and survival of T pseudonana in the presence of oil, and its inhibition can influence the composition and activity of the surrounding bacterial community.

Study on the Prevalence of Vascular Calcification in Different Types of Arteries and Influencing Factors in Maintenance Peritoneal Dialysis Patients.

OBJECTIVE: To investigate the occurrence of vascular calcification (VC) in different types of arteries in patients with maintenance peritoneal dialysis (PD) patients and its influencing factors. METHODS: This study enrolled PD patients with stable status who has received PD treatment for more than 6 months in Peking University People's Hospital. We used plain X-ray films of abdomen, pelvis, and hands to quantitatively evaluate VC of large artery (abdominal aorta, iliac artery), medium artery (femoral artery, radial artery), and small artery (finger arteries). Two radiologists read and scored radiographs blindly. Demographic data, clinical characteristics, Charlson comorbidity index (CCI), baseline and time-average laboratory indices including parameters of calcium phosphorus metabolism, serum albumin, PD adequacy were collected. A logistic regression model was used to estimate the influencing factors of different sites of VC. RESULTS: (1) 154 PD patients were enrolled in this study: seventy-eight males, mean age was 60.4 ± 13.9 years, and median PD duration was 24 (16.39) months. The major primary disease was diabetic nephropathy (39%). (2) Among the 154 PD patients, the proportion of calcification of large artery was the highest (found in 100 patients, accounting for 64.9%); then the medium artery (66, 42.9%); and 15 of small artery, accounting for 9.7%. (3) Logistic regression showed that older age, longer dialysis duration, lower baseline serum intact parathyroid hormone (iPTH), and higher CCI scores were independent risk factors of large artery calcification (p < 0.05), and higher CCI scores, higher baseline serum triglycerides (TG), lower baseline serum iPTH, and time-average iPTH were independent risk factors of medium and small arteries. CONCLUSIONS: In PD patients, the occurrence of large artery calcification was higher than others. Among different sites of VC, the abdominal aortic calcification was most likely to occur, and the proportion of small artery calcification was low. Calcification of medium and small arteries can exist alone without calcification of large artery. Large artery calcification was more likely to occur in patients with older age, longer dialysis duration, lower baseline serum iPTH levels and higher CCI scores. Patients with higher CCI scores, higher baseline TG and lower baseline iPTH, and time-average iPTH were more likely to develop small and medium artery calcification.

Perovskite Nanoparticles Toxicity Study on Airway Epithelial Cells.

Research on the toxicity of nanoparticles has developed over recent years due to their increasing prevalence in common everyday materials. Various nanoparticles have been reported to promote and induce mucus secretion, which could potentially lead to airway damages and respiratory complications. Lanthanum strontium manganite (LSM) is a nanoparticle widely used in solar oxidized fuel cells (SOFCs) due to its high electrical conductivity, high electrochemical activity for O2 reduction reaction, high thermal stability and compatibility of SOFC electrolytes, and most importantly, its microstructural stability and long-term performance. Very few studies have been conducted on LMS's toxicity, thus its effect on airway cells was investigated in this study. After treating trachea cells with increasing concentrations of LSM ranging up to 500 µg/ml, we found that it has a moderate effect on cell viability, ROS production, cytochrome C, and caspase 3 expression. Despite its minimal impact on stated apoptosis-inducing characteristics, LSM illustrated an inhibiting effect on mucus secretion. We obtained a decreasing trend in mucus secretion with an increased concentration of the LSM treatment. Overall, LSM's advancement in SOFCs necessitated a toxicity study, and although it does not show a significant toxicity to trachea cells, LSM reduces mucus secretion, and can potentially interfere with airway clearance.

Impact of exposure of crude oil and dispersant (Corexit) on aggregation of extracellular polymeric substances.

Spilled oil treated with Corexit dispersant can cause unintended impacts on marine environment systems including altering marine organic matter dynamics; however, impacts on microgels and marine oil snow (MOS) formation are still debated and remain to be fully understood. Extracellular polymeric substances (EPS) are a major source of marine organic carbon for MOS and microgel formation. EPS initial aggregation plays key roles in the oil degrading process and various biogeochemical reactions. Here we used four types of EPS with water accommodated fraction (WAF), chemically-enhanced WAF (CEWAF) and Corexit, to represent potential situations during oil spills and post-application of Corexit. We found that Corexit alone can inhibit EPS aggregation and disperse pre-existing microgels. CEWAF can enhance EPS aggregation with efficiency by up to 80%-100% and more aggregates accumulated within the air-water interface. Additionally, more hydrophobic EPS aggregates showed high resistance to Corexit dispersion while hydrophilic EPS were more sensitive. Effects of oil spills on marine gel particle formation are primarily determined by chemical characteristics (hydrophobicity and protein content) of the constituent EPS. This study offers unique insights for organic particle dynamics and identifies controlling factors for MOS or gel particles associated with oil spills and Corexit dispersant used.

Extracellular polymeric substances (EPS) producing and oil degrading bacteria isolated from the northern Gulf of Mexico.

Sinking marine oil snow was found to be a major mechanism in the transport of spilled oil from the surface to the deep sea following the Deepwater Horizon (DwH) oil spill. Marine snow formation is primarily facilitated by extracellular polymeric substances (EPS), which are mainly composed of proteins and carbohydrates secreted by microorganisms. While numerous bacteria have been identified to degrade oil, there is a paucity of knowledge on bacteria that produce EPS in response to oil and Corexit exposure in the northern Gulf of Mexico (nGoM). In this study, we isolated bacteria from surface water of the nGoM that grow on oil or Corexit dispersant. Among the 100 strains isolated, nine were identified to produce remarkable amounts of EPS. 16S rRNA gene analysis revealed that six isolates (strains C1, C5, W10, W11, W14, W20) belong to the genus Alteromonas; the others were related to Thalassospira (C8), Aestuariibacter (C12), and Escherichia (W13a). The isolates preferably degraded alkanes (17-77%), over polycyclic aromatic hydrocarbons (0.90-23%). The EPS production was determined in the presence of a water accommodated fraction (WAF) of oil, a chemical enhanced WAF (CEWAF), Corexit, and control. The highest production of visible aggregates was found in Corexit followed by CEWAF, WAF, and control; indicating that Corexit generally enhanced EPS production. The addition of WAF and Corexit did not affect the carbohydrate content, but significantly increased the protein content of the EPS. On the average, WAF and CEWAF treatments had nine to ten times more proteins, and Corexit had five times higher than the control. Our results reveal that Alteromonas and Thalassospira, among the commonly reported bacteria following the DwH spill, produce protein rich EPS that could have crucial roles in oil degradation and marine snow formation. This study highlights the link between EPS production and bacterial oil-degrading capacity that should not be overlooked during spilled oil clearance.

High-throughput label-free microcontact printing graphene-based biosensor for valley fever.

The highly prevalent and virulent disease in the Western Hemisphere Coccidioidomycosis, also known as Valley Fever, can cause serious illness such as severe pneumonia with respiratory failure. It can also take on a disseminated form where the infection spreads throughout the body. Thus, a serious impetus exists to develop effective detection of the disease that can also operate in a rapid and high-throughput fashion. Here, we report the assembly of a highly sensitive biosensor using reduced graphene oxide (rGO) with Coccidioides(cocci) antibodies as the target analytes. The facile design made possible by the scalable microcontact printing (µCP) surface patterning technique which enables rapid, ultrasensitive detection. It provides a wide linear range and sub picomolar (2.5 pg/ml) detection, while also delivering high selectivity and reproducibility. This work demonstrates an important advancement in the development of a sensitive label-free rGO biosensor for Coccidioidomycosis detection. This result also provides the potential application of direct pathogen diagnosis for the future biosensor development.

CeO2 nanoparticles attenuate airway mucus secretion induced by TiO2 nanoparticles.

Nanotoxicity studies associated with various nanoparticles (NPs) have attracted intense research interest due to the broader applications of nanoparticles in our daily lives. The exposure of nanoparticles can lead to hypersecretion and accumulation of airway mucus which are closely associated with many respiratory diseases. Titanium dioxide (TiO2), one of the PM10 components, is a major NP that is widely utilized in many commercial products. Our previous study established the connection between induced airway mucus secretion and TiO2 NPs. However, the countermeasure to reduce the harmful effects of TiO2 NPs, especially airway mucus secretion, remains unexplored. One of the potential candidates to reduce airway mucus secretion is cerium oxide (CeO2) NPs. It has been reported that CeO2 NPs can protect cells by diminishing ROS and inflammatory responses. Herein, our study shows that CeO2 NPs are able to reduce cytosolic Ca2+ changes and mitochondrial damage caused by TiO2 NPs. Our results provide the evidence that hypersecretion of mucus and apoptosis progression induced by TiO2 NPs can be attenuated by CeO2 NPs. This study highlights the potential capacity of CeO2 NPs as a supplementary material for TiO2 NPs applications in the future.

Serum Magnesium Abnormality and Influencing Factors of Serum Magnesium Level in Peritoneal Dialysis Patients: A Single-Center Study in Northern China.

BACKGROUND/AIMS: Both hypomagnesemia and hypermagnesemia have been associated with cardiovascular diseases, bone diseases, and mortality in dialysis patients. We aimed to investigate the prevalence of and influencing factors for abnormal serum Mg levels in patients on peritoneal dialysis (PD). METHODS: A cross-sectional study in Peking University People's Hospital recorded the demographic information, clinical characteristics, and laboratory data. Data were assessed and compared with the results from 2 other studies in China. RESULTS: Of 180 enrolled PD patients, the primary diseases were glomerulonephritis (38.3%) and diabetic nephropathy (38.3%). Mean serum Mg concentration was 1.02 ± 0.16 mmol/L; 67% had normal serum Mg concentrations, and 33% had hypermagnesemia. CONCLUSIONS: Hypermagnesemia is likely to occur in patients with higher serum phosphate, lower intact parathyroid hormone, and lower high-sensitivity C-reactive protein levels. Serum Mg level distributions in PD patients vary throughout China, may have different potential causes (such as geographical location and dietary habits) and should be further studied.

Effect of Engineered Nanoparticles on Exopolymeric Substances Release from Marine Phytoplankton.

Engineered nanoparticles (ENPs), products from modern nanotechnologies, can potentially impact the marine environment to pose serious threats to marine ecosystems. However, the cellular responses of marine phytoplankton to ENPs are still not well established. Here, we investigate four different diatom species (Odontella mobiliensis, Skeletonema grethae, Phaeodactylum tricornutum, Thalassiosira pseudonana) and one green algae (Dunaliella tertiolecta) for their extracellular polymeric substances (EPS) release under model ENP treatments: 25 nm titanium dioxide (TiO2), 10-20 nm silicon dioxide (SiO2), and 15-30 nm cerium dioxide (CeO2). We found SiO2 ENPs can significantly stimulate EPS release from these algae (200-800%), while TiO2 ENP exposure induced the lowest release. Furthermore, the increase of intracellular Ca2+ concentration can be triggered by ENPs, suggesting that the EPS release process is mediated through Ca2+ signal pathways. With better understanding of the cellular mechanism mediated ENP-induced EPS release, potential preventative and safety measures can be developed to mitigate negative impact on the marine ecosystem.

Corexit, oil and marine microgels.

Corexit, an EPA-approved chemical dispersant, was intensively used during the 2010 Deepwater Horizon Oil Spill in the Gulf of Mexico. Current studies surrounding Corexit have mainly focused on its toxicity and oil removal capacity. The potential impact of Corexit on the surface ocean carbon dynamics has remained largely unknown. The spontaneous assembly of DOM (dissolved organic matter) polymers into microgels (POM, particulate organic matter) was demonstrated previously that it can influence various critical processes, such as colloidal pump, microbial loops, and nutrition availability in the surface ocean. Here, we report that Corexit alone can significantly inhibit DOM microgel formation and reduce the stability of pre-existing microgels. However, Corexit and oil, Chemically Enhanced Water Accommodated Fraction (CEWAF), could effectively facilitate DOM microgel formation. The unanticipated disturbance of Corexit and oil spills on the critical DOM-POM continuum warrant particular caution and thus should be considered for future application of Corexit during oil spills.

Epistasis of oxidative stress-related enzyme genes on modulating the risks in oral cavity cancer.

BACKGROUND: The aim of this study was to evaluate the risks of the polymorphisms of oxidant stress-related enzymes on patients with oral cavity cancer by genotyping of manganese superoxide dismutase (MnSOD [1183T>C]), myeloperoxidase (MPO [-463G>A]), catalase (CAT [-15A>T]) and glutathione peroxidases 1 (GPx1 [Pro198Leu]). METHODS: A case-control study was conducted on 122 biopsy-proven oral cavity cancer patients with, at least, one of the past habits of cigarette smoking, alcohol drinking or betel-quid chewing, and 122 approximately age- and habit-matched controls. RESULTS: The independent risks of the polymorphisms for each enzyme on carcinogenicity were non-significant. The 2-order gene-gene interactions of the polymorphisms, assessed by using a logistic regression model, on risk did not show significant changes, neither. However, the epistasis, assessed by multifactor dimensionality reduction (MDR) for three-order (CAT, MnSOD, and MPO) and four-order was significant. Additionally, the fact that the levels of O(2)(-), GSSG and total GSH in the patients were significantly different according to certain genotypes which revealed that the polymorphisms of these enzymes could affect these parameters to some extent. CONCLUSIONS: The results suggested that the genetic-effects of the polymorphisms of these enzymes could slightly modify the risk in oral cavity cancer development individually, but significantly when they functioned together.