Observation of Seven Astrophysical Tau Neutrino Candidates with IceCube.

We report on a measurement of astrophysical tau neutrinos with 9.7 yr of IceCube data. Using convolutional neural networks trained on images derived from simulated events, seven candidate ν_{τ} events were found with visible energies ranging from roughly 20 TeV to 1 PeV and a median expected parent ν_{τ} energy of about 200 TeV. Considering backgrounds from astrophysical and atmospheric neutrinos, and muons from π^{±}/K^{±} decays in atmospheric air showers, we obtain a total estimated background of about 0.5 events, dominated by non-ν_{τ} astrophysical neutrinos. Thus, we rule out the absence of astrophysical ν_{τ} at the 5σ level. The measured astrophysical ν_{τ} flux is consistent with expectations based on previously published IceCube astrophysical neutrino flux measurements and neutrino oscillations.

Observation of high-energy neutrinos from the Galactic plane.

The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos. We searched for neutrino emission using machine learning techniques applied to 10 years of data from the IceCube Neutrino Observatory. By comparing diffuse emission models to a background-only hypothesis, we identified neutrino emission from the Galactic plane at the 4.5σ level of significance. The signal is consistent with diffuse emission of neutrinos from the Milky Way but could also arise from a population of unresolved point sources.

Evidence for neutrino emission from the nearby active galaxy NGC 1068.

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy's active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of [Formula: see text] neutrinos at tera-electron volt energies, with a global significance of 4.2σ, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera-electron volt gamma rays from this source.

Search for Unstable Sterile Neutrinos with the IceCube Neutrino Observatory.

We present a search for an unstable sterile neutrino by looking for a resonant signal in eight years of atmospheric ν_{µ} data collected from 2011 to 2019 at the IceCube Neutrino Observatory. Both the (stable) three-neutrino and the 3+1 sterile neutrino models are disfavored relative to the unstable sterile neutrino model, though with p values of 2.8% and 0.81%, respectively, we do not observe evidence for 3+1 neutrinos with neutrino decay. The best-fit parameters for the sterile neutrino with decay model from this study are Δm_{41}^{2}=6.7_{-2.5}^{+3.9} eV^{2}, sin^{2}2θ_{24}=0.33_{-0.17}^{+0.20}, and g^{2}=2.5π±1.5π, where g is the decay-mediating coupling. The preferred regions of the 3+1+decay model from short-baseline oscillation searches are excluded at 90% C.L.

Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale ν_{µ} Disappearance at IceCube.

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{µτ}. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90% confidence interval of -0.0041≤ε_{µτ}≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.

Search for Relativistic Magnetic Monopoles with Eight Years of IceCube Data.

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886 days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0.995c, without any explicit restriction on the monopole mass. We constrain the flux of relativistic cosmic magnetic monopoles to a level below 2.0×10^{-19} cm^{-2} s^{-1} sr^{-1} over the majority of the targeted speed range. This result constitutes the most strict upper limit to date for magnetic monopoles with ß≳0.8 and up to ß∼0.995 and fills the gap between existing limits on the cosmic flux of nonrelativistic and ultrarelativistic magnetic monopoles.

Association of a common interferon regulatory factor 5 (IRF5) variant with increased risk of systemic lupus erythematosus (SLE).

Interferon regulatory factor 5 (IRF5) belongs to a family of transcription factors that control the transactivation of type I interferon system-related genes, as well as the expression of several other genes involved in immune response, cell signalling, cell cycle control and apoptosis. Two recent studies reported a significant association between the IRF5/rs2004640 T allele and systemic lupus erythematosus (SLE). The purpose of this study was to determine whether the reported rs2004640 T allele association could be replicated in our independent SLE case-control sample. We genotyped DNA samples from 370 white SLE-affected female subjects and 462 white healthy female controls using the TaqMan Assay-on-Demand for rs2004640, and performed a case-control genetic association analysis. Frequency of the rs2004640 T allele was significantly higher in cases than in controls (56.5% vs. 50%; P= 0.008). The odds ratio for T allele carriers was 1.68 (95% CI: 1.20 - 2.34; P= 0.003). Our results in an independent case-control sample confirm the robust association of the IRF5/rs2004640 T allele with SLE risk, and further support the relevance of the type I interferon system in the pathogenesis of SLE and autoimmunity.

Cocaine activates platelets and increases the formation of circulating platelet containing microaggregates in humans.

OBJECTIVE: To determine whether there is evidence of platelet activation following in vivo cocaine administration in humans, as cocaine abuse is associated with myocardial infarction and stroke, and platelet activation leading to thrombosis is a possible mechanism. SETTING: University hospital. DESIGN AND SUBJECTS: Following a randomised, double blind crossover design, 14 healthy volunteers were studied twice, receiving cocaine (2 mg/kg intranasally) once and placebo once. Flow cytometric analysis of P-selectin expression (an alpha granule membrane protein found on the surface of activated platelets), quantification of the platelet specific proteins platelet factor 4 and beta thromboglobulin, and measurement of platelet containing microaggregate and platelet microparticle (fragment) formation were used to assess platelet activation. Circulating von Willebrand factor antigen (vWF) was measured to evaluate a possible role of endothelial stimulation concurrent with platelet activation. RESULTS: There was an increase in both platelet factor 4 (mean (SD), 16 (7) to 39 (22) IU/ml, p = 0. 04) and beta thromboglobulin (70 (20) to 98 (26) IU/ml, p < 0.01) at 120 minutes following cocaine administration. Platelet containing microaggregate formation was increased at 40 minutes (from 47 (3.2)% to 54 (2.0)%, p < 0.001) and 80 minutes (55 (2.5)%, p = 0.04). Bleeding time decreased following cocaine from 10 (1) to 9 (1) minutes (p = 0.07). No changes in any of the measured variables were noted following placebo administration. CONCLUSIONS: Cocaine exposure causes platelet activation, alpha granule release, and platelet containing microaggregate formation. These data support the view that cocaine, even at the relatively low doses commonly self administered by occasional abusers, may promote thrombosis and predispose healthy individuals to ischaemic events. Platelet inhibitors should be considered early in any patient with suspected cocaine related ischaemia.

von Willebrand disease and bleeding in women.

Menorrhagia is a common health problem in women, particularly those with bleeding disorders. Little is known about the course of menorrhagia or other bleeding symptoms in women with the most common congenital bleeding disorder, von Willebrand disease (vWD). We determined the prevalence of menorrhagia, bleeding symptoms and coagulation abnormalities associated with vWD, including factor VIII activity, von Willebrand factor (vWF) antigen, ristocetin cofactor and bleeding time (BT), on a cohort of 38 females with type 1 vWD referred for diagnosis and medical care. Menorrhagia was the most common bleeding symptom in females with vWD, occurring in 93.1% of adult women. Menorrhagia was also the most common initial bleeding symptom, occurring in 53.1% of adult women in all of whom it began at menarche, median 14 years of age. There was a delay from initial bleeding symptoms, at median age 12 years, to diagnosis, at median age 16 years, P=0.0049. Although 94% undergoing surgery had previous bleeding, a vWD diagnosis was known preoperatively in only 6.2%, resulting in potentially preventable bleeding. In summary, menorrhagia is the most common bleeding symptom in females with vWD and begins at menarche. Obtaining a personal and family bleeding history promotes early diagnosis, potentially prevents postoperative bleeding, and improves the health of women with vWD.

Increase in hepatitis C virus load in hemophiliacs during treatment with highly active antiretroviral therapy.

The effect of highly active antiretroviral therapy (HAART) on liver function and viral load of hepatitis C virus (HCV) was studied in 21 hemophilic men coinfected with HCV and human immunodeficiency virus (HIV). HCV RNA polymerase chain reaction was measured by branched DNA Quantiplex assay on frozen plasma samples obtained at baseline and at 24, 48, and 96 weeks after initiation of HAART. HCV RNA increased at 48 and 96 weeks after initiation of HAART therapy (198x105 Eq/mL [P=.03] and 227x105 Eq/mL [P<.0001], respectively, compared with baseline [141x105 Eq/mL]). This increase was associated with an increase in CD4 cell count and reduction in HIV viral load but no change in hepatic transaminases. With discontinuation of HAART, HCV RNA decreased as HIV RNA rebounded. Further study is required to clarify the histopathologic significance of this finding.

Adenotonsillectomy in children with von Willebrand disease.

OBJECTIVE: To review the effectiveness of a perioperative management protocol and our experience with a large population of patients with von Willebrand disease (vWD) who require adenotonsillar surgery (T&A). DESIGN: A retrospective review of the medical records of all patients having the diagnosis of vWD who underwent T&A between January 1, 1992, and July 31, 1996. SETTING: A tertiary care, university-based children's hospital. INTERVENTIONS: Patients having a preoperative diagnosis of vWD received a single intravenous dose of desmopressin acetate, 0.3 pg/kg, approximately 20 minutes before the induction of anesthesia. Beginning January 15, 1994, a standard management protocol involving the postoperative administration of fluids and electrolytes was followed. MAIN OUTCOME MEASURES: Operative blood loss and the incidence of postoperative bleeding and of hyponatremia. RESULTS: Of approximately 4800 patients who underwent T&A during the study period, 69 patients had a diagnosis of vWD. All 67 patients identified preoperatively received desmopressin; 2 were identified by postoperative workup as a result of excessive surgical bleeding. Minimal immediate postoperative bleeding was noted in 7 patients (10%), but none required intervention. Delayed bleeding occurred in 9 patients (13%); all were readmitted to the hospital for observation, 4 (6%) requiring operative cauterization. Substantial postoperative hyponatremia occurred in 3 patients, and 1 patient had seizure activity. Symptomatic hyponatremia has been avoided since a protocol of fluid and electrolyte administration was instituted. CONCLUSIONS: Although T&A can be performed safely in patients with vWD, it is not without an increased risk of postoperative hemorrhage. The administration of desmopressin has been reported to reduce the risk of bleeding, but it is not without risk. A protocol for fluid and electrolyte management is recommended.

Arterial thromboembolic events in patients with the factor V Leiden mutation.

BACKGROUND: The factor V Leiden mutation affects 6% of the United States population and is known to be associated with venous thrombosis. We identify, herein, 30 individuals with the Leiden mutation and known arterial thromboembolic events. METHODS: The factor V mutation was assessed using polymerase chain reaction. RESULTS: In the 16 patients sustaining a cerebrovascular accident, the mean age was 44.1 and 11 (69%) were younger than 50. Similarly, the 13 patients presenting with an acute myocardial infarction were relatively young with a mean age of 45.5, and 9 (65%) patients presented at less than 50 years of age. Radiographic information was available for 19 patients in this study. No significant arterial atherosclerotic disease was demonstrated in 18 (95%) of these patients. CONCLUSIONS: This study demonstrates an association between the factor V Leiden mutation and the development of unexplained arterial thromboembolic events, especially in younger patients without existing atherosclerotic disease.

Peripheral retinal neovascularization (Eales disease) associated with the factor V Leiden mutation.

PURPOSE: To illustrate a case of peripheral retinal neovascularization (Eales disease) in a patient who tested positive for the factor V Leiden mutation. METHODS: A 42-year-old woman had a 1-week history of blurred vision in her right eye. Her medical history was remarkable for a cerebrovascular accident. Ophthalmoscopy of the right eye disclosed a mild vitreous hemorrhage and a ridge of retinal neovascularization in the temporal periphery. The left fundus showed evidence of temporal retinal ischemia. A laboratory evaluation for hypercoagulability was positive for factor V Leiden mutation. RESULTS: Peripheral scatter laser photocoagulation was applied to the ischemic retina, and the neovascularization regressed. The patient began taking warfarin sodium to prevent further thrombotic events. CONCLUSION: A laboratory evaluation for coagulopathy, including the factor V Leiden mutation, should be added to the examination of patients with Eales disease, especially individuals with a history of a previous thrombotic event.

Aortic and renal artery thrombosis in a neonate: recovery with thrombolytic therapy.

This report describes a neonate with acute renal failure associated with extensive aortic and bilateral renal artery thrombosis attributed to inadequate breastfeeding and severe dehydration. Dialytic and general supportive care, together with concurrent anticoagulation, and continuous aggressive intrathrombic instillation of urokinase for 5 days resulted in near-complete thrombolysis. Renal functional recovery began 11 days after the onset of anuria. Despite ischemic atrophy of the left kidney, renal function and blood pressure were normal on follow-up. Thus, in neonates thrombolytic therapy may positively impact survival and recovery of renal function even in the setting of prolonged ischemic renal injury.

The factor V Leiden mutation: spectrum of thrombotic events and laboratory evaluation.

PURPOSE: This study aims to describe the spectrum of clinical thrombotic events and to compare the methods of laboratory evaluation for the newly described prothrombotic factor V Leiden mutation. METHODS: Specimens from 1376 patients with thrombotic events or their relatives were tested for the factor V Leiden mutation by polymerase chain reaction plus restriction digest from Jan. 1, 1995, to Mar. 31, 1996. Activated protein C (APC) resistance test data was available for 554 of these patients. Clinical information was available for 166 patients with the mutation. RESULTS: Of 1376 patients tested for factor V Leiden mutation, 270 (19.6%) were positive, with 12 homozygotes and 258 heterozygotes. Of 554 patients for whom APC resistance data was available, 221 (39.9%) had low APC resistance ratios (< or = 2.4); of these only 97 (43.9%) were factor V Leiden-positive. Among 333 samples with normal or elevated APC resistance ratios, 19 (5.7%) were later identified with the factor V Leiden mutation, despite the normal screening test. One hundred fourteen of 166 patients (68.7%) with the mutation had at least one thrombotic event, most commonly deep venous thrombosis and pulmonary embolus. Arterial cerebrovascular thrombotic events occurred in 11 patients (10%), and myocardial infarctions in eight (7%). The mean age of all patients with arterial thrombotic events was 45.4 years. CONCLUSIONS: The factor V mutation is a common cause of venous thromboses but may also be associated with the early presentation of arterial thrombotic events. The APC resistance test is a sensitive screening assay but has limitations of its specificity in clinical practice.

Low-dose aspirin and prednisone treatment of pregnancy loss caused by lupus anticoagulants.

The objective of this study was to ascertain the complications and the efficacy of low-dose aspirin (LDA) and prednisone therapy in women with pregnancy loss and "lupus anticoagulants" (LAC). During the period 1985 to 1993, 255 patients with two or more pregnancy losses (RPL) were tested for LAC with an activated partial thromboplastin time (aPTT) and a tissue thromboplastin inhibition index (TTI, normal value < 1.3). The diagnosis of LAC was established if two TTI values were > or = 1.3 or if a prolonged aPTT was measured in the patient's plasma that did not correct to normal by 1:1 mixing with normal plasma. We excluded patients with RPL who had only anticardiolipin antibodies. We treated 28 pregnancies in 21 women with LDA/prednisone for RPL associated with LAC. Therapy with LDA/prednisone was initiated as soon as a viable pregnancy was diagnosed. Therapy was continued until delivery in all but one case. Prednisone dose was minimized by measuring TTI and aPTT every 2 weeks and adjusting the dosage to maintain a TTI < or = 1.2 and to correct the aPTT to less than 36 seconds. Among the 28 pregnancies there were four (14%) first-trimester spontaneous abortions and four (14%) second-trimester fetal deaths. Of 20 surviving neonates (72%), seven were delivered after 37 weeks and 13 before 37 weeks (mean 35.9 +/- 2.3 weeks, range 31.5 to 40.4 weeks). Pre-term premature rupture of membranes occurred in three pregnancies, hypertensive disorders in six, and four small-for-gestational-age neonates were delivered (two stillborn). Mean birth weight of 20 surviving neonates was 2736 +/- 763 gm (range 900 to 3920 gm). Mean daily prednisone dose in 20 live births was 24.1 +/- 8.5 (SD) mg (range 11.3 to 49.3 mg/day) with mean duration of LDA/prednisone therapy of 185 +/- 40 days (range 97 to 223 days). Maximum prednisone dose was 60 mg/day (mean 36.8 +/- 12.7 mg/day). Only one serious maternal complication of LDA/prednisone therapy was observed. One neonate had talipes equinovarus that resolved without surgical therapy. LDA/prednisone therapy seemed effective and reasonably well tolerated in this population. These findings should be confirmed in a prospective, controlled investigation if such a trial can be organized and performed.

Evaluation and treatment of the plastic surgical patient having a potential to bleed.

The clinical plastic surgeon needs to be able to determine which of his or her patients are low risk and which of his or her patients require additional tests. Which patients can be operated on today, and which patients need to be delayed and possibly treated preoperatively? After a review of the literature, we present these guidelines: 1. Take a good history. 2. Stratify the risk to the patient. 3. Test as indicated. a. Don't necessarily rely on the bleeding time. b. Be aware of the high false-positive rate of coagulation tests. 4. Be mindful of the effects of certain medicines. 5. "Surgical" bleeding is the most common cause of bleeding and should prompt reoperation if coagulation tests are negative. 6. Consult a hematologist early as questions arise, particularly in patients stratified to moderate- and high-risk groups.