Explore the vast range of titles available.

We consider a multi-parameter model for randomly constructing simplicial complexes that interpolates between random clique complexes and Linial–Meshulam random k-dimensional complexes. Unlike these models, multi-parameter complexes exhibit nontrivial homology in numerous dimensions simultaneously. We establish upper and lower thresholds for the appearance of nontrivial cohomology in each dimension and characterize the behavior at criticality.

We consider a multi-parameter model for randomly constructing simplicial complexes. This model interpolates between random clique complexes and Linial-Meshulam random \\(k\\)-dimensional complexes, two models that have been extensively studied. While these models asymptotically exhibit nontrivial cohomology in only one or two dimensions, we show that in this generalized setting nontrivial cohomology can occur in several dimensions simultaneously. We establish upper and lower thresholds for the appearance of nontrivial cohomology in a particular dimension, and in some instances characterize the behavior at criticality.

The theory of supercharacters, recently developed by Diaconis-Isaacs and Andre, can be used to derive the fundamental algebraic properties of Ramanujan sums. This machinery frequently yields one-line proofs of difficult identities and provides many novel formulas. In addition to exhibiting a new application of supercharacter theory, this article also serves as a blueprint for future work since some of the abstract results we develop are applicable in much greater generality.

Moves to legalize marijuana highlight the urgency to investigate effects of chronic marijuana in the human brain. Here, we challenged 48 participants (24 controls and 24 marijuana abusers) with methylphenidate (MP), a drug that elevates extracellular dopamine (DA) as a surrogate for probing the reactivity of the brain to DA stimulation. We compared the subjective, cardiovascular, and brain DA responses (measured with PET and [ ¹¹C]raclopride) to MP between controls and marijuana abusers. Although baseline (placebo) measures of striatal DA D2 receptor availability did not differ between groups, the marijuana abusers showed markedly blunted responses when challenged with MP. Specifically, compared with controls, marijuana abusers had significantly attenuated behavioral (“self-reports” for high, drug effects, anxiety, and restlessness), cardiovascular (pulse rate and diastolic blood pressure), and brain DA [reduced decreases in distribution volumes (DVs) of [ ¹¹C]raclopride, although normal reductions in striatal nondisplaceable binding potential (BP ND)] responses to MP. In ventral striatum (key brain reward region), MP-induced reductions in DVs and BP ND (reflecting DA increases) were inversely correlated with scores of negative emotionality, which were significantly higher for marijuana abusers than controls. In marijuana abusers, DA responses in ventral striatum were also inversely correlated with addiction severity and craving. The attenuated responses to MP, including reduced decreases in striatal DVs, are consistent with decreased brain reactivity to the DA stimulation in marijuana abusers that might contribute to their negative emotionality (increased stress reactivity and irritability) and addictive behaviors.

Dapagliflozin, a sodium-glucose cotransporter-2 inhibitor, reduces cardiovascular death and worsening heart failure in patients with chronic heart failure and reduced ejection fraction. Early initiation during an acute heart failure (AHF) hospitalization may facilitate decongestion, improve natriuresis, and facilitate safe transition to a beneficial outpatient therapy for both diabetes and heart failure. The objective is to assess the efficacy and safety of initiating dapagliflozin within the first 24 hours of hospitalization in patients with AHF compared to usual care. DICTATE-AHF is a prospective, multicenter, open-label, randomized trial enrolling a planned 240 patients in the United States. Patients with type 2 diabetes hospitalized with hypervolemic AHF and an estimated glomerular filtration rate of at least 30 mL/min/1.73m2 are eligible for participation. Patients are randomly assigned 1:1 to dapagliflozin 10 mg once daily or structured usual care until day 5 or hospital discharge. Both treatment arms receive protocolized diuretic and insulin therapies. The primary endpoint is diuretic response expressed as the cumulative change in weight per cumulative loop diuretic dose in 40 mg intravenous furosemide equivalents. Secondary and exploratory endpoints include inpatient worsening AHF, 30-day hospital readmission for AHF or diabetic reasons, change in NT-proBNP, and measures of natriuresis. Safety endpoints include the incidence of hyper/hypoglycemia, ketoacidosis, worsening kidney function, hypovolemic hypotension, and inpatient mortality. The DICTATE-AHF trial will establish the efficacy and safety of early initiation of dapagliflozin during AHF across both AHF and diabetic outcomes in patients with diabetes.

Attention-deficit hyperactivity disorder (ADHD) is typically characterized as a disorder of inattention and hyperactivity/impulsivity but there is increasing evidence of deficits in motivation. Using positron emission tomography (PET), we showed decreased function in the brain dopamine reward pathway in adults with ADHD, which, we hypothesized, could underlie the motivation deficits in this disorder. To evaluate this hypothesis, we performed secondary analyses to assess the correlation between the PET measures of dopamine D2/D3 receptor and dopamine transporter availability (obtained with [ 11 C]raclopride and [ 11 C]cocaine, respectively) in the dopamine reward pathway (midbrain and nucleus accumbens) and a surrogate measure of trait motivation (assessed using the Achievement scale on the Multidimensional Personality Questionnaire or MPQ) in 45 ADHD participants and 41 controls. The Achievement scale was lower in ADHD participants than in controls (11±5 vs 14±3, P <0.001) and was significantly correlated with D2/D3 receptors (accumbens: r =0.39, P <0.008; midbrain: r =0.41, P <0.005) and transporters (accumbens: r =0.35, P <0.02) in ADHD participants, but not in controls. ADHD participants also had lower values in the Constraint factor and higher values in the Negative Emotionality factor of the MPQ but did not differ in the Positive Emotionality factor—and none of these were correlated with the dopamine measures. In ADHD participants, scores in the Achievement scale were also negatively correlated with symptoms of inattention (CAARS A, E and SWAN I). These findings provide evidence that disruption of the dopamine reward pathway is associated with motivation deficits in ADHD adults, which may contribute to attention deficits and supports the use of therapeutic interventions to enhance motivation in ADHD.

In patients with Staphylococcus aureus bacteremia or right-sided endocarditis, daptomycin was shown to be noninferior to standard antimicrobial therapy (vancomycin or an antistaphylococcal penicillin with low-dose gentamicin). Microbiologic evidence of treatment failure was more common in the daptomycin group, whereas treatment failure caused by an adverse event occurred more often in the standard-therapy group. In patients with Staphylococcus aureus bacteremia or right-sided endocarditis, daptomycin was shown to be noninferior to standard antimicrobial therapy. Staphylococcus aureus is a leading cause of bacteremia 1 , 2 and endocarditis. 3 , 4 S. aureus bacteremia is associated with serious complications, including endocarditis, in 30 to 40 percent of cases. 5 , 6 Treatment options for bacteremia and endocarditis caused by S. aureus, particularly methicillin-resistant S. aureus (MRSA), are limited. Vancomycin, the standard therapy for bloodstream infections attributable to MRSA, has been associated with suboptimal outcomes. 7 – 10 New agents for the treatment of S. aureus bacteremia and endocarditis are needed. Daptomycin is a cyclic lipopeptide antibiotic that is rapidly bactericidal in vitro against most clinically relevant gram-positive bacteria, including S. aureus . 11 – . . .

Brain dopamine dysfunction in attention deficit/hyperactivity disorder (ADHD) could explain why stimulant medications, which increase dopamine signaling, are therapeutically beneficial. However while the acute increases in dopamine induced by stimulant medications have been associated with symptom improvement in ADHD the chronic effects have not been investigated. We used positron emission tomography and [(11)C]cocaine (dopamine transporter radioligand) to measure dopamine transporter availability in the brains of 18 never-medicated adult ADHD subjects prior to and after 12 months of treatment with methylphenidate and in 11 controls who were also scanned twice at 12 months interval but without stimulant medication. Dopamine transporter availability was quantified as non-displaceable binding potential using a kinetic model for reversible ligands. Twelve months of methylphenidate treatment increased striatal dopamine transporter availability in ADHD (caudate, putamen and ventral striatum: +24%, p<0.01); whereas there were no changes in control subjects retested at 12-month interval. Comparisons between controls and ADHD participants revealed no significant difference in dopamine transporter availability prior to treatment but showed higher dopamine transporter availability in ADHD participants than control after long-term treatment (caudate: p<0.007; putamen: p<0.005). Upregulation of dopamine transporter availability during long-term treatment with methylphenidate may decrease treatment efficacy and exacerbate symptoms while not under the effects of the medication. Our findings also suggest that the discrepancies in the literature regarding dopamine transporter availability in ADHD participants (some studies reporting increases, other no changes and other decreases) may reflect, in part, differences in treatment histories.

Background Sepsis accounts for 30% to 50% of all in-hospital deaths in the United States. Other than antibiotics and source control, management strategies are largely supportive with fluid resuscitation and respiratory, renal, and circulatory support. Intravenous vitamin C in conjunction with thiamine and hydrocortisone has recently been suggested to improve outcomes in patients with sepsis in a single-center before-and-after study. However, before this therapeutic strategy is adopted, a rigorous assessment of its efficacy is needed. Methods The Vitamin C, Thiamine and Steroids in Sepsis (VICTAS) trial is a prospective, multi-center, double-blind, adaptive sample size, randomized, placebo-controlled trial. It will enroll patients with sepsis causing respiratory or circulatory compromise or both. Patients will be randomly assigned (1:1) to receive intravenous vitamin C (1.5 g), thiamine (100 mg), and hydrocortisone (50 mg) every 6 h or matching placebos until a total of 16 administrations have been completed or intensive care unit discharge occurs (whichever is first). Patients randomly assigned to the comparator group are permitted to receive open-label stress-dose steroids at the discretion of the treating clinical team. The primary outcome is consecutive days free of ventilator and vasopressor support (VVFDs) in the 30 days following randomization. The key secondary outcome is mortality at 30 days. Sample size will be determined adaptively by using interim analyses with pre-stated stopping rules to allow the early recognition of a large mortality benefit if one exists and to refocus on the more sensitive outcome of VVFDs if an early large mortality benefit is not observed. Discussion VICTAS is a large, multi-center, double-blind, adaptive sample size, randomized, placebo-controlled trial that will test the efficacy of vitamin C, thiamine, and hydrocortisone as a combined therapy in patients with respiratory or circulatory dysfunction (or both) resulting from sepsis. Because the components of this therapy are inexpensive and readily available and have very favorable risk profiles, demonstrated efficacy would have immediate implications for the management of sepsis worldwide. Trial registration ClinicalTrials.gov Identifier: NCT03509350 . First registered on April 26, 2018, and last verified on December 20, 2018. Protocol version: 1.4, January 9, 2019

Acanthosis nigricans (AN) is a strong correlate of obesity and is considered a marker of insulin resistance (IR). AN is associated with various other cardiometabolic risk factors (CMRFs). However, the direct causal relationship of IR with AN in obesity has been debated. Therefore, we aimed to examine the complex causal relationships among the troika of AN, obesity, and IR in Mexican Americans (MAs). We used data from 670 non-diabetic MA children, aged 6-17 years (49% girls). AN (prevalence 33%) severity scores (range 0-5) were used as a quasi-quantitative trait (AN-q) for analysis. We used the program SOLAR for determining phenotypic, genetic, and environmental correlations between AN-q and CMRFs (e.g., BMI, HOMA-IR, lipids, blood pressure, hs-C-reactive protein (CRP), and Harvard physical fitness score (PFS)). The genetic and environmental correlations were subsequently used in mediation analysis (AMOS program). Model comparisons were made using goodness-of-fit indexes. Heritability of AN-q was 0.75 (p<0.0001). It was positively/significantly (p<0.05) correlated with traits such as BMI, HOMA-IR, and CRP, and negatively with HDL-C and PFS. Of the models tested, indirect mediation analysis of BMI→HOMA-IR→AN-q yielded lower goodness-of-fit than a partial mediation model where BMI explained the relationship with both HOMA-IR and AN-q simultaneously. Using complex models, BMI was associated with AN-q and IR mediating most of the CMRFs; but no relationship between IR and AN-q. Our study suggests that obesity explains the association of IR with AN, but no causal relationship between IR and AN in Mexican American children.