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1.
Article in English | MEDLINE | ID: mdl-38869743

ABSTRACT

BACKGROUND: New onset atrial fibrillation (NOAF) is a common occurrence after transcatheter aortic valve replacement (TAVR) and portends a poorer prognosis. The optimal strategy for managing NOAF in this population is uncertain. METHODS: This retrospective cohort study utilized deidentified patient data from the TriNetX Research Network. Patients with TAVR and NOAF were stratified into a rhythm control cohort if they were treated with antiarrhythmics, received AF ablation, or underwent cardioversion within 1 year of AF diagnosis. A rate control cohort was similarly defined by the absence of rhythm control strategies and treatment with a beta blocker, calcium channel blocker, or digoxin. After 1:1 propensity score matching, the Kaplan-Meier survival analysis and Cox proportional hazard ratios (HRs) were used to compare outcomes at 7 years of follow-up. RESULTS: We identified 569 patients in each cohort following propensity matching. At 7 years, the primary composite outcome of all-cause death, myocardial infarction, cerebrovascular accident, and heart failure hospitalization was not significantly different between the rhythm and rate control cohorts (HR 0.99, 95% CI 0.83-1.18). The individual components of the primary outcome in addition to all-cause hospitalization were also similar between the groups. CONCLUSIONS: Similar outcomes were seen among patients receiving an early rhythm or rate control strategy to manage NOAF after TAVR. The attenuated benefits of an early rhythm control strategy observed in this setting may be due to the overall high burden of comorbidities and advanced age of these patients.

2.
Am J Med ; 2024 Jun 24.
Article in English | MEDLINE | ID: mdl-38925496

ABSTRACT

Human papillomavirus (HPV) is the most common sexually transmitted infection in the US and worldwide, with more than 42 million Americans infected with types of HPV that are known to cause disease. While the link between HPV and the development of a variety of cancers has been strongly established, recent literature has demonstrated a potential association between HPV and increased risk of cardiovascular disease. Nevertheless, despite plausible mechanisms for the development of cardiovascular disease with HPV infection, a causative relationship has yet to be firmly established, in part due to potential confounding risk factors between the two. In this 2-part series, we discuss the emerging relationship between HPV and cardiovascular disease. In part 1, we focus on the pathophysiology of HPV infection and potential mechanisms for the development of cardiovascular disease.

3.
Expert Opin Ther Targets ; 28(5): 385-400, 2024 May.
Article in English | MEDLINE | ID: mdl-38700451

ABSTRACT

INTRODUCTION: The cardiac conduction system (CCS) is crucial for maintaining adequate cardiac frequency at rest and modulation during exercise. Furthermore, the atrioventricular node and His-Purkinje system are essential for maintaining atrioventricular and interventricular synchrony and consequently maintaining an adequate cardiac output. AREAS COVERED: In this review article, we examine the anatomy, physiology, and pathophysiology of the CCS. We then discuss in detail the most common genetic mutations and the molecular mechanisms of cardiac conduction disease (CCD) and provide our perspectives on future research and therapeutic opportunities in this field. EXPERT OPINION: Significant advancement has been made in understanding the molecular mechanisms of CCD, including the recognition of the heterogeneous signaling at the subcellular levels of sinoatrial node, the involvement of inflammatory and autoimmune mechanisms, and the potential impact of epigenetic regulations on CCD. However, the current treatment of CCD manifested as bradycardia still relies primarily on cardiovascular implantable electronic devices (CIEDs). On the other hand, an If specific inhibitor was developed to treat inappropriate sinus tachycardia and sinus tachycardia in heart failure patients with reduced ejection fraction. More work is needed to translate current knowledge into pharmacologic or genetic interventions for the management of CCDs.


Subject(s)
Cardiac Conduction System Disease , Heart Conduction System , Molecular Targeted Therapy , Humans , Animals , Heart Conduction System/physiopathology , Cardiac Conduction System Disease/physiopathology , Cardiac Conduction System Disease/therapy , Cardiac Conduction System Disease/drug therapy , Mutation , Drug Development , Heart Failure/physiopathology , Heart Failure/therapy , Heart Failure/drug therapy , Epigenesis, Genetic , Sinoatrial Node/physiopathology
4.
Cardiol Rev ; 2024 Feb 27.
Article in English | MEDLINE | ID: mdl-38411170

ABSTRACT

Pregnancy-associated myocardial infarction is an overall uncommon event, but can be associated with significant maternal and fetal morbidity and mortality. In contrast to myocardial infarction in the general nonpregnant population, the mechanism of pregnancy-associated myocardial infarction is most commonly due to nonatherosclerotic mechanisms such as coronary dissection, vasospasm, or thromboembolism. The diagnosis of pregnancy-associated myocardial infarction can be challenging, requiring a high index of suspicion for prompt recognition and management. Furthermore, the management of pregnancy-associated myocardial infarction can be complex due to maternal and fetal considerations and may vary based on the specific underlying mechanism of the myocardial infarction. This review aims to review the recent literature on pregnancy-associated myocardial infarction and summarize the epidemiology, mechanisms, diagnosis, and treatment strategies for this uncommon entity.

6.
Am J Med ; 136(12): 1147-1159, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37380060

ABSTRACT

Chronic kidney disease patients are at increased risk of cardiovascular disease, which is the leading cause of mortality among this population. In addition, chronic kidney disease is a major risk factor for the development of coronary artery disease and is widely regarded as a coronary artery disease risk equivalent. Medical therapy is the cornerstone of coronary artery disease management in the general population. However, there are few trials to guide medical therapy of coronary artery disease in chronic kidney disease, with most data extrapolated from clinical trials of mainly non-chronic kidney disease patients, which were not adequately powered to evaluate this subgroup. There is some evidence to suggest that the efficacy of certain therapies such as aspirin and statins is attenuated with declining estimated glomerular filtration rate, with questionable benefit among end-stage renal disease (ESRD) patients. Furthermore, chronic kidney disease and ESRD patients are at higher risk of potential side effects with therapy, which may limit their use. In this review, we summarize the available evidence supporting the safety and efficacy of medical therapy of coronary artery disease in chronic kidney disease and ESRD patients. We also discuss the data on new emerging therapies, including PCSK9i, SGLT2i, GLP1 receptor agonists, and nonsteroidal mineralocorticoid receptor antagonists, which show promise at reducing risk of cardiovascular events in the chronic kidney disease population and may offer additional treatment options. Overall, dedicated studies directly evaluating chronic kidney disease patients, particularly those with advanced chronic kidney disease and ESRD, are greatly needed to establish the optimal medical therapy for coronary artery disease and improve outcomes in this vulnerable population.


Subject(s)
Cardiovascular Diseases , Coronary Artery Disease , Kidney Failure, Chronic , Renal Insufficiency, Chronic , Humans , Coronary Artery Disease/complications , Coronary Artery Disease/epidemiology , Renal Insufficiency, Chronic/epidemiology , Kidney Failure, Chronic/complications , Kidney Failure, Chronic/therapy , Cardiovascular Diseases/prevention & control , Cardiovascular Diseases/complications , Risk Factors
7.
Pacing Clin Electrophysiol ; 46(7): 788-795, 2023 07.
Article in English | MEDLINE | ID: mdl-37323035

ABSTRACT

INTRODUCTION: Implantable loop recorders (ILR) are used to screen for atrial fibrillation (AF) in patients with cryptogenic stroke (CS). However, there is limited real-world data regarding the long-term rate of AF detection using ILR and management consequences in patients with CS. The objective is to assess the rate of AF detection in patients with CS in a real-world study over 36 months of follow-up and its consequences on stroke prevention. METHODS: This retrospective study included patients with an ILR placed for CS at Baylor College of Medicine and Baylor St. Luke's Medical Center between January 2014 and July 2021. The primary outcome was AF detection in patients with ILR. The secondary outcome was the rate of subsequent strokes after ILR placement in patients with or without diagnosed AF. The AF detection rate in our cohort was compared to the rate in CRYSTAL-AF Trial at 36-month follow-up. The impact of AF detection on clinical management was examined. RESULTS: We identified 225 patients. 51.1% were women and 38.2% African American. Among 85 patients with ILR labeled AF, 43 patients had true AF, and 42 had incorrectly labeled AF (48.3% false positive). The estimated AF detection rate at 36 months follow-up was 28.6% (95% CI, 26.6%-30.6%). 58.1% of patients with AF were initiated on oral anticoagulation, 80.0% of whom were started on a direct oral anticoagulant. 13.8% of patients had recurrent strokes after ILR implantation; 4 of whom were diagnosed with AF. CONCLUSION: Compared to CRYSTAL-AF, the AF detection rate in our cohort is similar, but this cohort includes a higher proportion of female and African American patients. Most patients with recurrent strokes after ILR implant did not have AF during 36 months of monitoring.


Subject(s)
Atrial Fibrillation , Ischemic Stroke , Stroke , Humans , Female , Male , Retrospective Studies , Electrocardiography, Ambulatory , Stroke/prevention & control , Stroke/complications , Ischemic Stroke/complications
8.
Front Plant Sci ; 14: 1184678, 2023.
Article in English | MEDLINE | ID: mdl-37346116

ABSTRACT

The endoplasmic reticulum (ER) serves essential functions in eukaryotic cells, including protein folding, transport of secretory proteins, and lipid synthesis. The ER is a highly dynamic organelle that generates various types of compartments. Among them, the ER body is specifically present in plants in the Brassicaceae family and plays a crucial role in chemical defense against pathogens. The NAI2 protein is essential for ER body formation, and its ectopic overexpression is sufficient to induce ER body formation even in the leaves of Nicotiana benthamiana, where the ER body does not naturally exist. Despite the significance of NAI2 in ER body formation, the mechanism whereby NAI2 mediates ER body formation is not fully clear. This study aimed to investigate how two domains of Arabidopsis NAI2, the Glu-Phe-Glu (EFE) domain (ED) and the NAI2 domain (ND), contribute to ER body formation in N. benthamiana leaves. Using co-immunoprecipitation and bimolecular fluorescence complementation assays, we found that the ND is critical for homomeric interaction of NAI2 and ER body formation. Moreover, deletion of ED induced the formation of enlarged ER bodies, suggesting that ED plays a regulatory role during ER body formation. Our results indicate that the two domains of NAI2 cooperate to induce ER body formation in a balanced manner.

9.
J Cardiovasc Electrophysiol ; 34(8): 1718-1729, 2023 08.
Article in English | MEDLINE | ID: mdl-37343033

ABSTRACT

INTRODUCTION: Conduction system pacing (CSP) is observed to produce greater improvements in echocardiographic and hemodynamic parameters as compared to conventional biventricular pacing (BiVP). However, whether these surrogate endpoints directly translate to improvements in hard clinical outcomes such as death and heart failure hospitalization (HFH) with CSP remains uncertain as studies reporting these outcomes are scarce. The aim of this meta-analysis was to analyze the existing data to compare the clinical outcomes of CSP versus BiVP. METHODS: A systematic search of the Embase and PubMed database was performed for studies comparing CSP and BiVP for patients indicated to receive a CRT device. The coprimary endpoints were all-cause mortality and HFH. Other secondary outcomes included change in left ventricular ejection fraction (LVEF), change in NYHA class, and increase in NYHA class ≥1. A random-effects model was chosen a priori to analyze the composite effects given the anticipated heterogeneity of included trials. RESULTS: Twenty-one studies (4 randomized and 17 observational) were identified reporting either primary outcome and were included in the meta-analysis. In total 1960 patients were assigned to CSP and 2367 to BiVP. Median follow-up time was 10.1 months (ranging 2-33 months). CSP was associated with a significant reduction in all-cause mortality (odds ratio [OR] 0.68, 95% confidence interval [CI]: 0.56-0.83) and HFH (OR 0.52, 95% CI: 0.44-0.63). Mean improvement in LVEF was also greater with CSP (mean difference 4.26, 95% CI: 3.19-5.33). Reduction in NYHA class was significantly greater with CSP (mean difference -0.36, 95% CI: -0.49 to -0.22) and the number of patients with an increase in NYHA class ≥1 was significantly greater with CSP (OR 2.02, 95% CI: 1.70-2.40). CONCLUSIONS: CSP was associated with a significant reduction in all-cause mortality and HFH when compared to conventional BiVP for CRT. Further large-scale randomized trials are needed to verify these observations.


Subject(s)
Cardiac Resynchronization Therapy , Heart Failure , Humans , Cardiac Resynchronization Therapy/adverse effects , Stroke Volume , Ventricular Function, Left , Treatment Outcome , Cardiac Conduction System Disease/therapy , Heart Failure/diagnosis , Heart Failure/therapy
11.
Antioxidants (Basel) ; 12(3)2023 Feb 28.
Article in English | MEDLINE | ID: mdl-36978849

ABSTRACT

Salt stress is a critical environmental stress that impairs plant growth and development, especially in crop productivity; therefore, understanding the salt response in plants is the basis for their development of salt tolerance. Under salinity, soybean mitogen-activated protein kinase 6 (GmMPK6) is activated and positively regulates reactive oxygen species (ROS) generation. However, it is not yet elucidated how GmMPK6 regulates ROS generation and its role in salt tolerance. Here, we show that GmMPK6, solely activated in NaCl treatment, and gene expression of GmRbohI1 was not only reduced by MPK inhibitor SB202190 in NaCl treatment, but also increased in a GMKK1-expressing protoplast. Furthermore, SB202190 and the NADPH-oxidase inhibitor, diphenyleneiodonium chloride, increased susceptibility to salt stress. The expression of GmRD19A was induced by NaCl treatment, but this expression was compromised by SB202190. Consequently, we revealed that GmMPK6 induces ROS generation through the transcriptional regulation of GmRbohI1 and increases salt tolerance in soybean.

12.
J Interv Card Electrophysiol ; 66(3): 737-756, 2023 Apr.
Article in English | MEDLINE | ID: mdl-35411440

ABSTRACT

BACKGROUND: Catheter-based ablation to perform pulmonary vein isolation (PVI) has established itself as a mainstay in the rhythm control strategy of atrial fibrillation. This review article aims to provide an overview of recent advances in atrial fibrillation ablation technology. METHODS: We reviewed the available literature and clinical trials of innovations in atrial fibrillation ablation technologies including ablation catheter designs, alternative energy sources, esophageal protection methods, electroanatomical mapping, and novel ablation targets. RESULTS: Innovative radiofrequency (RF) catheter designs maximize energy delivery while avoiding overheating associated with conventional catheters. Single-shot balloon catheters in the form of cryoballoons, radiofrequency, and laser balloons have proven effective at producing pulmonary vein isolation and improving procedural efficiency and reproducibility. Pulsed field ablation (PFA) is a highly anticipated novel nonthermal energy source under development, which demonstrates selective ablation of the myocardium, producing durable lesions while also minimizing collateral damage. Innovative devices for esophageal protection including esophageal deviation and cooling devices have been developed to reduce esophageal complications. Improved electroanatomical mapping systems are being developed to help identify additional non-pulmonary triggers, which may benefit from ablation, especially with persistent atrial fibrillation. Lastly, the vein of Marshall alcohol ablation has been recently studied as an adjunct therapy for improving outcomes with catheter ablation for persistent atrial fibrillation. CONCLUSIONS: Numerous advances have been made in the field of atrial fibrillation ablation in the past decade. While further long-term data is still needed for these novel technologies, they show potential to improve procedural efficacy and safety.


Subject(s)
Atrial Fibrillation , Catheter Ablation , Pulmonary Veins , Humans , Atrial Fibrillation/surgery , Reproducibility of Results , Treatment Outcome , Catheters , Pulmonary Veins/surgery , Catheter Ablation/methods
13.
Am J Physiol Heart Circ Physiol ; 324(3): H259-H278, 2023 03 01.
Article in English | MEDLINE | ID: mdl-36563014

ABSTRACT

The sinoatrial node (SAN) is the primary pacemaker of the heart. Normal SAN function is crucial in maintaining proper cardiac rhythm and contraction. Sinus node dysfunction (SND) is due to abnormalities within the SAN, which can affect the heartbeat frequency, regularity, and the propagation of electrical pulses through the cardiac conduction system. As a result, SND often increases the risk of cardiac arrhythmias. SND is most commonly seen as a disease of the elderly given the role of degenerative fibrosis as well as other age-dependent changes in its pathogenesis. Despite the prevalence of SND, current treatment is limited to pacemaker implantation, which is associated with substantial medical costs and complications. Emerging evidence has identified various genetic abnormalities that can cause SND, shedding light on the molecular underpinnings of SND. Identification of these molecular mechanisms and pathways implicated in the pathogenesis of SND is hoped to identify novel therapeutic targets for the development of more effective therapies for this disease. In this review article, we examine the anatomy of the SAN and the pathophysiology and epidemiology of SND. We then discuss in detail the most common genetic mutations correlated with SND and provide our perspectives on future research and therapeutic opportunities in this field.


Subject(s)
Sick Sinus Syndrome , Sinoatrial Node , Humans , Aged , Sick Sinus Syndrome/genetics , Sinoatrial Node/metabolism , Heart Conduction System , Arrhythmias, Cardiac/metabolism , Heart Rate/physiology
14.
Curr Probl Cardiol ; 48(3): 101509, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36402213

ABSTRACT

Cardiorenal syndrome (CRS) is an increasingly recognized diagnostic entity associated with high morbidity and mortality among acutely ill heart failure (HF) patients with acute and/ or chronic kidney diseases (CKD). While traditionally viewed as a state of decline in glomerular filtration rate (GFR) due to decreased renal perfusion, mainly due to therapeutic interventions to relieve congestive in HF, recent insights into the underlying pathophysiologic mechanisms of CRS led to a broader definition and further classification of CRS into 5 distinct types. In this comprehensive review, we discuss the classification of CRS, highlighting the underlying common pathogenetic pathways of heart failure and kidney injury, including increased congestion, neurohormonal dysregulation, oxidative stress as well as inflammation, and cytokine storm that are particularly evident in COVID-19 patients with multiorgan failure and also in those with other disorders including sepsis, systemic lupus erythematosus and amyloidosis. In this review we also present the recent advances in the diagnostic strategies of CRS including cardiac and renal biomarkers as well as advanced cardiac and renal imaging techniques that are available to aid in the diagnosis as well as in the prognostication of this disorder. Finally, we discuss the various therapeutic options available to-date, including fluid optimization, hemofiltration, renal replacement therapy as well as the role of SGLT2 inhibitors in light of recent data from RCTs. It is important to note that, CRS population are either excluded or underrepresented, at best, in major RCTs and therefore, therapeutic recommendations are largely extrapolated from HF and CKD clinical trials.


Subject(s)
COVID-19 , Cardio-Renal Syndrome , Heart Failure , Renal Insufficiency, Chronic , Humans , Cardio-Renal Syndrome/diagnosis , Cardio-Renal Syndrome/etiology , Cardio-Renal Syndrome/therapy , COVID-19/complications , Heart Failure/diagnosis , Heart Failure/etiology , Heart Failure/therapy , Renal Insufficiency, Chronic/complications , Biomarkers
15.
J Interv Card Electrophysiol ; 66(3): 585-595, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36089635

ABSTRACT

BACKGROUND: There is limited data comparing radiofrequency (RF) and cryoballoon (CB) ablation for persistent atrial fibrillation (AF), which tends to have higher recurrence rates following ablation compared to paroxysmal AF. METHODS: A systematic search of the Embase, PubMed, and Cochrane database was performed for studies comparing RF vs CB ablation for persistent AF. An inverse-variance random-effects model was used to calculate the composite effects. RESULTS: One randomized and 9 observational studies were identified, with 1650 patients receiving CB and 1706 patients receiving RF ablation. Mean follow-up time ranged from 12 to 48 months. Freedom from recurrent atrial tachyarrhythmia was similar with the two modalities (HR 0.93, 95% CI 0.80 to 1.08, I2 0%). Total complications were similar in both groups (RR 1.05, 95% CI 0.73 to 1.53, I2 0%) although rates of phrenic nerve palsy (PNP) were greater with CB (RR 4.13, 95% CI 1.49 to 11.46, I2 0%). Shorter procedure times were observed with CB (mean reduction 43.77 min, 95% CI 66.45 to 21.09 min, I2 96%) with no difference in fluoroscopy time (mean difference 0.82 min, 95% CI - 11.92 to 13.55 min, I2 100%). CONCLUSIONS: In persistent AF patients, CB ablation has similar efficacy and overall safety as compared to RF ablation. While CB is associated with significantly shorter procedure times, the improved procedural efficiency with CB is offset by increased rates of PNP and the potential need for touch-up RF ablation.


Subject(s)
Atrial Fibrillation , Catheter Ablation , Cryosurgery , Pulmonary Veins , Radiofrequency Ablation , Humans , Atrial Fibrillation/surgery , Treatment Outcome , Catheter Ablation/methods , Cryosurgery/methods , Pulmonary Veins/surgery , Recurrence
16.
Plants (Basel) ; 11(21)2022 Nov 04.
Article in English | MEDLINE | ID: mdl-36365437

ABSTRACT

Influenza viruses are a major public health threat that causes repetitive outbreaks. In recent years, genotype 4 (G4) reassortant Eurasian avian-like (EA) H1N1 (G4 EA H1N1) has garnered attention as a potential novel pandemic strain. The necessity of developing vaccines against G4 EA H1N1 is growing because of the increasing cases of human infection and the low cross-reactivity of the strain with current immunity. In this study, we produced a G4 EA H1N1-derived neuraminidase (G4NA) as a vaccine candidate in Nicotiana benthamiana. The expressed G4NA was designed to be accumulated in the endoplasmic reticulum (ER). The M-domain of the human receptor-type tyrosine-protein phosphatase C was incorporated into the expression cassette to enhance the translation of G4NA. In addition, the family 3 cellulose-binding module and Brachypodium distachyon small ubiquitin-like modifier sequences were used to enable the cost-effective purification and removal of unnecessary domains after purification, respectively. The G4NA produced in plants displayed high solubility and assembled as a tetramer, which is required for the efficacy of an NA-based vaccine. In a mouse immunization model, the G4NA produced in plants could induce significant humoral immune responses. The plant-produced G4NA also stimulated antigen-specific CD4 T cell activation. These G4NA vaccine-induced immune responses were intensified by the administration of the antigen with a vaccine adjuvant. These results suggest that G4NA produced in plants has great potential as a vaccine candidate against G4 EA H1N1.

17.
Chemosphere ; 308(Pt 2): 136408, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36103922

ABSTRACT

Ciprofloxacin antibiotic (CIP) is one of the antibiotics with the highest rate of antibiotic resistance, if used and managed improperly, can have a negative impact on the ecosystem. In this research, ZnO modified g-C3N4 photocatalyst was prepared and applied for the decomposition of CIP antibiotic compounds in water. The removal performance of CIP by using ZnO/g-C3N4 reached 93.8% under pH 8.0 and an increasing amount of catalyst could improve the degradation performance of the pollutant. The modified ZnO/g-C3N4 completely oxidized CIP at a low concentration of 1 mg L-1 and the CIP removal efficiency slightly decreases (around 13%) at a high level of pollutant (20 mg L-1). The degradation rate of CIP by doped sample ZnO/g-C3N4 was 4.9 times faster than that of undoped g-C3N4. The doped catalyst ZnO/g-C3N4 also displayed high reusability for decomposition of CIP with 89.8% efficiency remaining after 3 cycles. The radical species including ·OH, ·O2- and h+ are important in the CIP degradation process. In addition, the proposed mechanism for CIP degradation by visible light-assisted ZnO/g-C3N4 was claimed.


Subject(s)
Environmental Pollutants , Zinc Oxide , Anti-Bacterial Agents/chemistry , Catalysis , Ciprofloxacin/chemistry , Ecosystem , Light , Photolysis , Water
18.
Sci Rep ; 12(1): 15576, 2022 09 16.
Article in English | MEDLINE | ID: mdl-36114274

ABSTRACT

The gearbox has the advantage of being able to change the torque and rotational speed according to the gear ratio and has high power transmission efficiency by transmitting power through the contact of the gear pair. When evaluating the strength and fatigue life of a gearbox using a design load or an equivalent load, there is a possibility that the results will be very different from the actual ones. Therefore, in this study, the load duration distribution (LDD) constructed based on the actual workload was used to evaluate the strength and fatigue life of the gearbox reliably. As a result of evaluating the strength and fatigue life of the gearbox using LDD, it was confirmed that the existing gearbox did not satisfy the target lifespan in the operating environment. Therefore, the reasons for these results were analyzed, and design modification was performed based on the analyzed results. As a result of design modification, shaft deflection decreased by rearrangement of the bearings, from an overhung type to a straddle type, thereby improving the fatigue life of gears and bearings. Finally, the load distribution acting on the gear tooth surface was improved through micro-geometry modification of the gears.


Subject(s)
Fatigue , Zea mays , Torque
19.
New Phytol ; 236(4): 1339-1357, 2022 11.
Article in English | MEDLINE | ID: mdl-35946374

ABSTRACT

A network of peptidases governs proteostasis in plant chloroplasts and mitochondria. This study reveals strong genetic and functional interactions in Arabidopsis between the chloroplast stromal CLP chaperone-protease system and the PREP1,2 peptidases, which are dually localized to chloroplast stroma and the mitochondrial matrix. Higher order mutants defective in CLP or PREP proteins were generated and analyzed by quantitative proteomics and N-terminal proteomics (terminal amine isotopic labeling of substrates (TAILS)). Strong synergistic interactions were observed between the CLP protease system (clpr1-2, clpr2-1, clpc1-1, clpt1, clpt2) and both PREP homologs (prep1, prep2) resulting in embryo lethality or growth and developmental phenotypes. Synergistic interactions were observed even when only one of the PREP proteins was lacking, suggesting that PREP1 and PREP2 have divergent substrates. Proteome phenotypes were driven by the loss of CLP protease capacity, with little impact from the PREP peptidases. Chloroplast N-terminal proteomes showed that many nuclear encoded chloroplast proteins have alternatively processed N-termini in prep1prep2, clpt1clpt2 and prep1prep2clpt1clpt2. Loss of chloroplast protease capacity interferes with stromal processing peptidase (SPP) activity due to folding stress and low levels of accumulated cleaved cTP fragments. PREP1,2 proteolysis of cleaved cTPs is complemented by unknown proteases. A model for CLP and PREP activity within a hierarchical chloroplast proteolysis network is proposed.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Amines/metabolism , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Chloroplast Proteins/metabolism , Chloroplasts/metabolism , Endopeptidase Clp/genetics , Endopeptidase Clp/metabolism , Peptide Hydrolases/metabolism , Proteome/metabolism
20.
Chemosphere ; 307(Pt 3): 135956, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35964720

ABSTRACT

In this work, alginate-modified biochar derived from rice husk waste was synthesized using a simple process. The modified biochar (MBC) and rice husk biochar (RhBC) were investigated for removing Pb (II) ions in wastewater. The BET result displayed significantly improved specific surface area of MBC up to 120 m2/g along with a total pore volume of 0.653 cm3/g. FTIR spectrums presented the higher oxygen-contained functional groups of MBC as compared to RhBC, resulting in increasing adsorption capacity of Pb (II). MBC had higher adsorption capacity (112.3 mg/g) and faster removal rate (0.0081 g mg-1 min-1) than those of RhBC (41.2 mg/g and 0.00025 g mg-1 min-1). Modified RhBC can remove more than 99% of Pb (II) from wastewater and it could be utilized for three cycles with a removal performance of over 90%. In addition, the Pb adsorption mechanism by using MBC was proposed and the practical application of MBC for the treatment of wastewater in Vietnam was discussed.


Subject(s)
Oryza , Water Pollutants, Chemical , Adsorption , Alginates , Charcoal , Ions , Kinetics , Lead , Oxygen , Wastewater , Water Pollutants, Chemical/analysis
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