p53 Represses the Mevalonate Pathway to Mediate Tumor Suppression.

There are still gaps in our understanding of the complex processes by which p53 suppresses tumorigenesis. Here we describe a novel role for p53 in suppressing the mevalonate pathway, which is responsible for biosynthesis of cholesterol and nonsterol isoprenoids. p53 blocks activation of SREBP-2, the master transcriptional regulator of this pathway, by transcriptionally inducing the ABCA1 cholesterol transporter gene. A mouse model of liver cancer reveals that downregulation of mevalonate pathway gene expression by p53 occurs in premalignant hepatocytes, when p53 is needed to actively suppress tumorigenesis. Furthermore, pharmacological or RNAi inhibition of the mevalonate pathway restricts the development of murine hepatocellular carcinomas driven by p53 loss. Like p53 loss, ablation of ABCA1 promotes murine liver tumorigenesis and is associated with increased SREBP-2 maturation. Our findings demonstrate that repression of the mevalonate pathway is a crucial component of p53-mediated liver tumor suppression and outline the mechanism by which this occurs.

MDM2 and MDMX promote ferroptosis by PPARα-mediated lipid remodeling.

MDM2 and MDMX, negative regulators of the tumor suppressor p53, can work separately and as a heteromeric complex to restrain p53's functions. MDM2 also has pro-oncogenic roles in cells, tissues, and animals that are independent of p53. There is less information available about p53-independent roles of MDMX or the MDM2-MDMX complex. We found that MDM2 and MDMX facilitate ferroptosis in cells with or without p53. Using small molecules, RNA interference reagents, and mutant forms of MDMX, we found that MDM2 and MDMX, likely working in part as a complex, normally facilitate ferroptotic death. We observed that MDM2 and MDMX alter the lipid profile of cells to favor ferroptosis. Inhibition of MDM2 or MDMX leads to increased levels of FSP1 protein and a consequent increase in the levels of coenzyme Q10, an endogenous lipophilic antioxidant. This suggests that MDM2 and MDMX normally prevent cells from mounting an adequate defense against lipid peroxidation and thereby promote ferroptosis. Moreover, we found that PPARα activity is essential for MDM2 and MDMX to promote ferroptosis, suggesting that the MDM2-MDMX complex regulates lipids through altering PPARα activity. These findings reveal the complexity of cellular responses to MDM2 and MDMX and suggest that MDM2-MDMX inhibition might be useful for preventing degenerative diseases involving ferroptosis. Furthermore, they suggest that MDM2/MDMX amplification may predict sensitivity of some cancers to ferroptosis inducers.

Wild-type and cancer-related p53 proteins are preferentially degraded by MDM2 as dimers rather than tetramers.

The p53 tumor suppressor protein is the most well studied as a regulator of transcription in the nucleus, where it exists primarily as a tetramer. However, there are other oligomeric states of p53 that are relevant to its regulation and activities. In unstressed cells, p53 is normally held in check by MDM2 that targets p53 for transcriptional repression, proteasomal degradation, and cytoplasmic localization. Here we discovered a hydrophobic region within the MDM2 N-terminal domain that binds exclusively to the dimeric form of the p53 C-terminal domain in vitro. In cell-based assays, MDM2 exhibits superior binding to, hyperdegradation of, and increased nuclear exclusion of dimeric p53 when compared with tetrameric wild-type p53. Correspondingly, impairing the hydrophobicity of the newly identified N-terminal MDM2 region leads to p53 stabilization. Interestingly, we found that dimeric mutant p53 is partially unfolded and is a target for ubiquitin-independent degradation by the 20S proteasome. Finally, forcing certain tumor-derived mutant forms of p53 into dimer configuration results in hyperdegradation of mutant p53 and inhibition of p53-mediated cancer cell migration. Gaining insight into different oligomeric forms of p53 may provide novel approaches to cancer therapy.

MDM2, MDMX, and p73 regulate cell-cycle progression in the absence of wild-type p53.

The p53 tumor suppressor protein, known to be critically important in several processes including cell-cycle arrest and apoptosis, is highly regulated by multiple mechanisms, most certifiably the Murine Double Minute 2-Murine Double Minute X (MDM2-MDMX) heterodimer. The role of MDM2-MDMX in cell-cycle regulation through inhibition of p53 has been well established. Here we report that in cells either lacking p53 or expressing certain tumor-derived mutant forms of p53, loss of endogenous MDM2 or MDMX, or inhibition of E3 ligase activity of the heterocomplex, causes cell-cycle arrest. This arrest is correlated with a reduction in E2F1, E2F3, and p73 levels. Remarkably, direct ablation of endogenous p73 produces a similar effect on the cell cycle and the expression of certain E2F family members at both protein and messenger RNA levels. These data suggest that MDM2 and MDMX, working at least in part as a heterocomplex, may play a p53-independent role in maintaining cell-cycle progression by promoting the activity of E2F family members as well as p73, making them a potential target of interest in cancers lacking wild-type p53.

When and why are employees willing to engage in voice behavior: a power cognition perspective.

Previous studies have found that sense of power is an important predictor of employee voice; however, the mechanism underlying the relationship between these factors remains unclear. To explore this mechanism, 642 valid questionnaires from 45 enterprises were used to conduct an empirical test based on the approach-inhibition theory of power. The results showed that sense of power can affect error risk taking positively, error risk taking mediates the relationship between sense of power and employee voice; and power congruence moderates both the direct relationship between sense of power and employee voice and their indirect relationship via error risk taking. This study thus provides a useful reference for improving employees' enthusiasm for voice behavior and can help enhance the competitiveness of enterprises.

Contemporary device management of cardiogenic shock following acute myocardial infarction.

Despite advances in the overall management of acute myocardial infarction (AMI), cardiogenic shock in the setting of AMI (CS-AMI) continues to be associated with poor patient outcomes. There are multiple devices that can be used in CS-AMI to support the failing circulation, although their utility in improving outcomes as compared with conventional pharmacotherapy of vasopressors and inotropes remains to be established. This contemporary review provides an update on the evidence base for each of these techniques. In CS-AMI, acute thrombotic occlusion of a major epicardial artery leads to hypoxia and myocardial ischaemia in the territory subtended by that vessel. The resultant regional dysfunction in myocardial contractility can severely compromise stroke volume and result in acute circulatory failure, systemic hypoperfusion, lactic acidosis, multi-organ failure and ultimately death.

Efficacy and safety of low-dose colchicine in patients with coronary disease: a systematic review and meta-analysis of randomized trials.

AIMS: Recent randomized trials demonstrated a benefit of low-dose colchicine added to guideline-based treatment in patients with recent myocardial infarction or chronic coronary disease. We performed a systematic review and meta-analysis to obtain best estimates of the effects of colchicine on major adverse cardiovascular events (MACE). METHODS AND RESULTS: We searched the literature for randomized clinical trials of long-term colchicine in patients with atherosclerosis published up to 1 September 2020. The primary efficacy endpoint was MACE, the composite of myocardial infarction, stroke, or cardiovascular death. We combined the results of five trials that included 11 816 patients. The primary endpoint occurred in 578 patients. Colchicine reduced the risk for the primary endpoint by 25% [relative risk (RR) 0.75, 95% confidence interval (CI) 0.61-0.92; P = 0.005], myocardial infarction by 22% (RR 0.78, 95% CI 0.64-0.94; P = 0.010), stroke by 46% (RR 0.54, 95% CI 0.34-0.86; P = 0.009), and coronary revascularization by 23% (RR 0.77, 95% CI 0.66-0.90; P < 0.001). We observed no difference in all-cause death (RR 1.08, 95% CI 0.71-1.62; P = 0.73), with a lower incidence of cardiovascular death (RR 0.82, 95% CI 0.55-1.23; P = 0.34) counterbalanced by a higher incidence of non-cardiovascular death (RR 1.38, 95% CI 0.99-1.92; P = 0.060). CONCLUSION: Our meta-analysis indicates that low-dose colchicine reduced the risk of MACE as well as that of myocardial infarction, stroke, and the need for coronary revascularization in a broad spectrum of patients with coronary disease. There was no difference in all-cause mortality and fewer cardiovascular deaths were counterbalanced by more non-cardiovascular deaths.

Colchicine in Patients With Acute Coronary Syndrome: The Australian COPS Randomized Clinical Trial.

BACKGROUND: Inflammation plays a crucial role in clinical manifestations and complications of acute coronary syndromes (ACS). Colchicine, a commonly used treatment for gout, has recently emerged as a novel therapeutic option in cardiovascular medicine owing to its anti-inflammatory properties. We sought to determine the potential usefulness of colchicine treatment in patients with ACS. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled trial involving 17 hospitals in Australia that provide acute cardiac care service. Eligible participants were adults (18-85 years) who presented with ACS and had evidence of coronary artery disease on coronary angiography managed with either percutaneous coronary intervention or medical therapy. Patients were assigned to receive either colchicine (0.5 mg twice daily for the first month, then 0.5 mg daily for 11 months) or placebo, in addition to standard secondary prevention pharmacotherapy, and were followed up for a minimum of 12 months. The primary outcome was a composite of all-cause mortality, ACS, ischemia-driven (unplanned) urgent revascularization, and noncardioembolic ischemic stroke in a time to event analysis. RESULTS: A total of 795 patients were recruited between December 2015 and September 2018 (mean age, 59.8±10.3 years; 21% female), with 396 assigned to the colchicine group and 399 to the placebo group. Over the 12-month follow-up, there were 24 events in the colchicine group compared with 38 events in the placebo group (P=0.09, log-rank). There was a higher rate of total death (8 versus 1; P=0.017, log-rank) and, in particular, noncardiovascular death in the colchicine group (5 versus 0; P=0.024, log-rank). The rates of reported adverse effects were not different (colchicine 23.0% versus placebo 24.3%), and they were predominantly gastrointestinal symptoms (colchicine, 23.0% versus placebo, 20.8%). CONCLUSIONS: The addition of colchicine to standard medical therapy did not significantly affect cardiovascular outcomes at 12 months in patients with ACS and was associated with a higher rate of mortality. Registration: URL: https://www.anzctr.org.au; Unique identifier: ACTRN12615000861550.

Epidemiology of COVID-19 Infection in Hospitalized End-Stage Kidney Disease Patients in a Predominantly African-American Population.

BACKGROUND: End-stage kidney disease patients on dialysis are particularly susceptible to COVID-19 infection due to comorbidities, age, and logistic constraints of dialysis making social distancing difficult. We describe our experience with hospitalized dialysis patients with COVID-19 and factors associated with mortality. METHODS: From March 1, 2020, to May 31, 2020, all dialysis patients admitted to 4 Emory Hospitals and tested for COVID-19 were identified. Sociodemographic information and clinical and laboratory data were obtained from the medical record. Death was defined as an in-hospital death or transfer to hospice for end-of-life care. Patients were followed until discharge or death. RESULTS: Sixty-four dialysis patients with COVID-19 were identified. Eighty-four percent were African-American. The median age was 64 years, and 59% were males. Four patients were on peritoneal dialysis, and 60 were on hemodialysis for a median time of 3.8 years, while 31% were obese. Fever (72%), cough (61%), and diarrhea (22%) were the most common symptoms at presentation. Thirty-three percent required admission to intensive care unit, and 23% required mechanical ventilation. The median length of stay was 10 days, while 11 patients (17%) died during hospitalization and 17% were discharged to a temporary rehabilitation facility. Age >65 years (RR 13.7, CI: 1.9-100.7), C-reactive protein >100 mg/dL (RR 8.3, CI: 1.1-60.4), peak D-dimer >3,000 ng/mL (RR 4.3, CI: 1.03-18.2), bilirubin >1 mg/dL (RR 3.9, CI: 1.5-10.4), and history of peripheral vascular disease (RR 3.2, CI: 1.2-9.1) were associated with mortality. Dialysis COVID-19-infected patients were more likely to develop thromboembolic complications than those without COVID-19 (RR 3.7, CI: 1.3-10.1). CONCLUSION: In a predominantly African-American population, the mortality of end-stage kidney disease patients admitted with COVID-19 infection was 17%. Age, C-reactive protein, D-dimer, bilirubin, and history of peripheral vascular disease were associated with worse survival.

Breaking the deadlock of calcified coronary artery lesions: A contemporary review.

Percutaneous coronary intervention (PCI) of severely calcified lesions is known to result in lower procedural success rates, higher complication rates, and worse long-term clinical outcomes compared to noncalcified lesions. Adequate lesion preparation through calcium modification is crucial in ensuring procedural success and reducing adverse cardiovascular outcomes. There are numerous calcium modification devices currently available whose usefulness depends on the nature of the calcific disease and its anatomical distribution. It can be challenging for the interventionists to decide which device is best suited for their patient. There is also emerging evidence for intravascular imaging in guiding selection of calcium modification devices using parameters such as calcium distribution and depth that directly impact on procedural success and clinical outcomes. In this review we aim to discuss the pathophysiology of coronary calcification, evaluate strategies and technologies of calcium modification and propose an A-M-A-S-A algorithm in managing calcified coronary lesions.

Utility of Zwolle Risk Score in Guiding Low-Risk STEMI Discharge.

BACKGROUND: Despite emerging evidence suggesting that selected patients presenting with ST-segment elevation myocardial infarction (STEMI) treated successfully with primary percutaneous coronary intervention (PPCI) may be considered for early discharge, STEMI patients are typically hospitalised longer to monitor for serious complications. METHODS: We assessed the feasibility of identifying low-risk STEMI patients in our institution for early discharge using the Zwolle risk score (ZRS). We evaluated consecutive STEMI patients who underwent successful PPCI within the period 1 January 2016 to 31 December 2017. Low-risk was defined as ZRS≤3. Demographic, angiographic characteristics, length of stay (LOS), and 30-day major adverse cardiovascular events (MACE) defined as cardiac death, stroke, congestive cardiac failure, and non-fatal myocardial infarction, were recorded. RESULTS: There were 183 STEMI patients in our study cohort (mean age 62.0±12.2 years, 77.0% male). The median ZRS was 2 (interquartile range 1-4) with 132 (72.1%) patients classified as low-risk. The overall 30-day MACE and mortality rates were 10.4% and 3.3% respectively. None of the 35 (26.5%) low-risk patients who were discharged within 72 hours experienced MACE at 30 days. Low-risk STEMI patients had significantly shorter median LOS (86.3 vs. 93.2 hours, p=0.002), lower 30-day MACE (4.5% vs. 25.5%, p<0.0001) and mortality (0% vs. 11.8%, p<0.0001) compared to high-risk group (ZRS>3). Receiver operating characteristic (ROC) curve analyses for ZRS in predicting 30-day MACE and mortality yielded C-statistics of 0.79 (95%CI 0.68-0.90, p<0.0001) and 0.98 (95%CI 0.95-1.00, p<0.0001) respectively. CONCLUSION: Low-risk STEMI patients stratified by Zwolle risk score, who were treated successfully with PPCI, experienced low 30-day MACE and mortality rates, indicating that early discharge may be safe in these patients. Larger studies are warranted to evaluate the safety of ZRS-guided early discharge of STEMI patients, as well as the economic and psychological impacts.

The Tail That Wags the Dog: How the Disordered C-Terminal Domain Controls the Transcriptional Activities of the p53 Tumor-Suppressor Protein.

The p53 tumor suppressor is a transcription factor (TF) that exerts antitumor functions through its ability to regulate the expression of multiple genes. Within the p53 protein resides a relatively short unstructured C-terminal domain (CTD) that remarkably participates in virtually every aspect of p53 performance as a TF. Because these aspects are often interdependent and it is not always possible to dissect them experimentally, there has been a great deal of controversy about the CTD. In this review we evaluate the significance and key features of this interesting region of p53 and its impact on the many aspects of p53 function in light of previous and more recent findings.

Elevated Triglycerides to High-Density Lipoprotein Cholesterol (TG/HDL-C) Ratio Predicts Long-Term Mortality in High-Risk Patients.

BACKGROUND: Elevated triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) ratio has been utilised as a predictor of outcomes in patients with adverse cardiometabolic risk profiles. In this study, we examined the prognostic value of elevated TG/HDL-C level in an Australian population of patients with high clinical suspicion of coronary artery disease (CAD) presenting for coronary angiography. METHODS: Follow-up data was collected for 482 patients who underwent coronary angiography in a prospective cohort study. The primary endpoint was all-cause mortality and the secondary endpoint was a major adverse cardiac event (MACE). Patients were stratified into two groups according to their baseline TG/HDL-C ratio, using a TG/HDL-C ratio cut point of 2.5. RESULTS: The mean follow-up period was 5.1 ± 1.2 years, with 49 all-cause deaths. Coronary artery disease on coronary angiography was more prevalent in patients with TG/HDL-C ratio ≥2.5 (83.6% vs. 69.4%, p = 0.03). On the Kaplan-Meier analysis, patients with TG/HDL-C ratio ≥2.5 had worse long-term prognosis (p = 0.04). On multivariate Cox regression adjusting for established cardiovascular risk factors and CAD on coronary angiography, TG/HDL-C ratio ≥2.5 was an independent predictor of long-term all-cause mortality (hazard ratio [HR] 2.10, 95% confidence interval [CI] 1.04-4.20, p = 0.04). On multivariate logistic regression adjusting for known cardiovascular risk factors and CAD on coronary angiography, TG/HDL-C ratio ≥2.5 was strongly associated with an increased risk of long-term MACE (odds ratio [OR] 2.72, 95% CI 1.42-5.20, p = 0.002). CONCLUSIONS: Elevated TG/HDL-C ratio is an independent predictor of long-term all-cause mortality and is strongly associated with an increased risk of MACE.

Synthesis of Functionalized Tetrahydropyridines by SnCl4 -Mediated [4+2] Cycloaddition between Donor-Acceptor Cyclobutanes and Nitriles.

Cycloadditions of strained carbocycles promoted by Lewis acids are powerful methods to construct heterocyclic frameworks. In fact, the formal [3+2] cycloadditions of donor-acceptor (DA) cyclopropanes with nitriles has seen particular success in synthesis. In this work, we report on the first [4+2] cycloaddition of nitriles with DA cyclobutanes by Lewis acid activation. Tetrahydropyridine derivatives were obtained in up to 91 % yield from various aryl-activated cyclobutane diesters and aliphatic or aromatic nitriles.

ICU Interventions in Ischemic Stroke Patients Treated Using Liberalized IV-tPA Criteria.

BACKGROUND AND OBJECTIVE: Current standard practice guidelines recommend ICU admission for ischemic stroke patients treated with intravenous tissue plasminogen activator (IV-tPA). More recently, the trend in stroke care is to broaden eligibility for IV thrombolysis. Two examples are a more liberal inclusion criteria known as SMART criteria (sIV-tPA), and the transfer of patients to comprehensive stroke centers (CSC). The present study characterizes ICU interventions in these patients. Understanding which stroke patients that require ICU-level care may allow for placement of patients in the appropriate level of care at hospital admission. METHODS: We performed a retrospective review of consecutive transfer and nontransfer sIV-tPA-treated patients admitted to the ICU at a CSC. We evaluated the frequency, timing, and nature of ICU interventions. RESULTS: Three hundred and thirty one patients were treated with sIV-tPA and 42% required ICU interventions during ICU admission. Of patients requiring ICU interventions, 98% had an ICU intervention performed in triage, prior to admission. National Institute of Health Stroke Scale score only had a moderate association to requirement of ICU interventions. Neither transferring patients to a CSC nor the number of standard IV-tPA contraindications increased ICU interventions. CONCLUSIONS: Liberalized IV-tPA administration did not increase ICU interventions. Nearly all patients that required ICU interventions declared this need in triage, prior to ICU admission. This timing of ICU intervention use during triage is highly sensitive for whether a patient will require ongoing ICU-level care during hospital admission. Identifying ICU intervention use in triage may allow for more effective placement of post-IV-tPA patients in the appropriate inpatient care setting, leading to better utilization of scarce ICU resources.

Generalized Safety and Efficacy of Simplified Intravenous Thrombolysis Treatment (SMART) Criteria in Acute Ischemic Stroke: The MULTI SMART Study.

BACKGROUND: Common intravenous recombinant tissue plasminogen activator (IV rt-PA) exclusion criteria may substantially limit the use of thrombolysis. Preliminary data have shown that the SMART (Simplified Management of Acute stroke using Revised Treatment) criteria greatly expand patient eligibility by reducing thrombolysis exclusions, but they have not been assessed on a large scale. We evaluated the safety and efficacy of general adoption of SMART thrombolysis criteria to a large regional stroke network. METHODS: Retrospective analysis of consecutive patients who received IV thrombolysis within a regional stroke network was performed. Patients were divided into those receiving thrombolysis locally versus at an outside hospital. The primary outcome was modified Rankin Scale score (≤1) at discharge and the main safety outcome was symptomatic intracranial hemorrhage (sICH) rate. RESULTS: There were 539 consecutive patients, and 50.5% received thrombolysis at an outside facility. Ninety percent of the patients possessed common conventional IV rt-PA contraindications. There were no significant differences between local and network treated patients in favorable outcome (45.4% versus 37.4%; odds ratio [OR], .72; P > .09), mortality (9% versus 14%; OR, 1.6; P > .07), or sICH rate (2.6% versus 5.1%; OR, 2.0; P = .13). Multivariate analysis showed no association between receiving IV rt-PA at an outlying spoke hospital and higher rate of sICH or worse outcome at discharge. CONCLUSIONS: Generalized application of SMART criteria is safe and effective. Widespread application of these criteria could substantially increase the proportion of patients who might qualify for treatment.

Holographic lattices give the graviton an effective mass.

We discuss the dc conductivity of holographic theories with translational invariance broken by a background lattice. We show that the presence of the lattice induces an effective mass for the graviton via a gravitational version of the Higgs mechanism. This allows us to obtain, at leading order in the lattice strength, an analytic expression for the dc conductivity in terms of the size of the lattice at the horizon. In locally critical theories this leads to a power law resistivity that is in agreement with an earlier field theory analysis of Hartnoll and Hofman.

Reduced clopidogrel metabolism in a multiethnic population: prevalence and rates of recurrent cerebrovascular events.

BACKGROUND: Concern has recently been raised over the possibility of a reduced efficacy of clopidogrel because of genetic variations in cytochrome P450, family 2, subfamily C, polypeptide 19 (CYP2C19) metabolism. A black box warning from the US Food and Drug Administration recommends that all patients be tested. It has been estimated that approximately 3% (range 2-14%) of the population are poor metabolizers, but few data are available for cerebrovascular patients. The objective of this study is to evaluate the frequency and effects of variability in CYP2C19 metabolism in patients with cerebrovascular disease. METHODS: A retrospective review of all patients with stroke and transient ischemic attack (TIA) tested for the clopidogrel CYP2C19 genotype was performed, with a collection of data including race/ethnicity, CYP2C19 status, and the presence of recurrent vascular events. RESULTS: A total of 53 cerebrovascular patients were tested, consisting of 5.7% poor (n = 3), 26.4% intermediate (n = 14), 62.3% extensive (n = 33), 3.8% indeterminate (n = 2), and 1.9% "mixed ultra rapid and poor" (n = 1) metabolizers. Only 10 of 38 white patients (26.3%; 95% confidence interval [CI] 0.14-0.42) were intermediate or poor metabolizers, compared with 7 of 15 (46.7%; 95% CI 0.25-0.70) nonwhites. Of 43 patients treated with clopidogrel, 3 of 27 extensive metabolizers (11.1%; 95% CI 0.04-0.28) had recurrent cerebrovascular events compared with 33.3% of intermediate metabolizers (4/12; 95% CI 0.14-0.61) and 50% of poor metabolizers (1/2; 95% CI 0.09-0.90). CONCLUSIONS: These data suggest that the proportion of poor/intermediate clopidogrel metabolizers in cerebrovascular patients is comparable to cardiovascular studies and these patients may have an increased risk of recurrent cerebrovascular events. Routine CYP2C19 testing may be warranted.

Centralization or decentralization? Power allocation in team innovation management.

Power disparity, as an important form of internal team hierarchy, presents a "double-edged sword effect". To reconcile the inconsistent effects and systematically explore the different mechanisms of power disparity, this study constructs a comprehensive theoretical model based on power functionalism and power conflict theory, with team coordination and team conflict as dual mediators, and power legitimacy as moderator. By collecting valid questionnaires from 76 teams across 27 different types of companies in various regions, statistical analysis and hypothesis testing were conducted on the data. The results conclude that power disparity positively influences team innovation performance through the team coordination path and negatively affects it through the team conflict path. However, under the moderating effect of power legitimacy, the negative effect of the team conflict path is suppressed, and the positive effect of the team coordination path is strengthened, thus ensuring that power disparity has a positive effect on team innovation performance. This study provides a useful reference for designing the power hierarchy within enterprises, and offers profound insights into effective organizational structure and decision-making processes.