Light curves of the neutron star merger GW170817/SSS17a: Implications for r-process nucleosynthesis

On 17 August 2017, gravitational waves (GWs) were detected from a binary neutron star merger, GW170817, along with a coincident short gamma-ray burst, GRB 170817A. An optical transient source, Swope Supernova Survey 17a (SSS17a), was subsequently identified as the counterpart of this event. We present ultraviolet, optical, and infrared light curves of SSS17a extending from 10.9 hours to 18 days postmerger. We constrain the radioactively powered transient resulting from the ejection of neutron-rich material. The fast rise of the light curves, subsequent decay, and rapid color evolution are consistent with multiple ejecta components of differing lanthanide abundance. The late-time light curve indicates that SSS17a produced at least ~0.05 solar masses of heavy elements, demonstrating that neutron star mergers play a role in rapid neutron capture (r-process) nucleosynthesis in the universe.

Swope Supernova Survey 2017a (SSS17a), the optical counterpart to a gravitational wave source

On 17 August 2017, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo interferometer detected gravitational waves (GWs) emanating from a binary neutron star merger, GW170817. Nearly simultaneously, the Fermi and INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory) telescopes detected a gamma-ray transient, GRB 170817A. At 10.9 hours after the GW trigger, we discovered a transient and fading optical source, Swope Supernova Survey 2017a (SSS17a), coincident with GW170817. SSS17a is located in NGC 4993, an S0 galaxy at a distance of 40 megaparsecs. The precise location of GW170817 provides an opportunity to probe the nature of these cataclysmic events by combining electromagnetic and GW observations.

Hippocampal atrophy is not a major determinant of regional hypometabolism in temporal lobe epilepsy

PURPOSE

The pathophysiologic basis for the [18F]fluorodeoxyglucose positron-emission tomography (FDG-PET) temporal lobe hypometabolism in patients with hippocampal sclerosis (HS) is uncertain. We tested the hypothesis that hippocampal atrophy, which is strongly correlated with hippocampal cell loss, is largely responsible for the regional hypometabolism in HS.

METHODS

Regions of interest (ROIs) on FDG-PET scanning were determined in the medial, lateral, and posterior temporal lobe, thalamus, and basal ganglia. A right/left asymmetry index for each ROI was calculated. These results were correlated with hippocampal magnetic resonance imaging (MRI) volume ratios.

RESULTS

There was no correlation between the magnitudes of the FDG-PET asymmetry index and the MRI volume ratio for the mesial or lateral temporal regions (r = -0.09, r = -0.04). When the right/left asymmetry index was compared with the right/left hippocampal volume ratio, correlations for the mesial temporal ROI (r = 0.79, p < 0.0001) and lateral temporal ROI (r = 0.57, p < 0.0005) were found. These, however, simply indicated that both tests accurately reflect the side of the epileptogenic region. The concordance of the side of relative hypometabolism of the FDG-PET with the side of the hippocampal atrophy was higher for the mesial temporal region (100%) than for the lateral (77.5%).

CONCLUSIONS

The lack of correlation between the magnitudes of the ratios argues against hippocampal atrophy and cell loss having a central role in the FDG-PET temporal hypometabolism.

Degree of left hippocampal atrophy correlates with severity of neuropsychological deficits

The relationship between the degree and distribution of hippocampal atrophy measured by volumetric magnetic resonance imaging and severity of memory deficits in 25 patients with temporal lobe epilepsy secondary to mesial temporal sclerosis was assessed. Hippocampal volumes were expressed as a ratio of smaller to larger, normal ratio greater than 0.95. Neuropsychology tests included: subtests of the WAIS-R, Rey Auditory Verbal Learning Task, Rey Figure and the Austin Maze. Degree of left hippocampal atrophy in patients with left temporal lobe epilepsy was associated with severity of verbal memory deficits as measured by RAVLT total recall (P < 0.05), delayed recall (P < 0.001), story recognition (P < 0.001), list recognition (P < 0.001) and final delayed recall (P < 0.001) and recall of the Rey Figure (P < 0.01). There was no association between degree of right hippocampal atrophy and any of the memory tests. Diffuse left hippocampal atrophy was associated with more severe verbal memory deficits than anterior atrophy. We conclude, the association between degree of left hippocampal atrophy and verbal memory provides further evidence of the predominant involvement of the left hippocampus in verbal memory. The finding of a relationship between degree of left hippocampal atrophy and measures of non-verbal function suggests these tests are dependent on verbal memory, or that mesial temporal sclerosis is a bilateral but asymmetrical condition.

Temporal lobe epilepsy caused by mesial temporal sclerosis and temporal neocortical lesions. A clinical and electroencephalographic study of 46 pathologically proven cases

This study aims to determine whether there are important clinico-electrical differences between patients with temporal lobe epilepsy (TLE) secondary to mesial temporal sclerosis (MTS) and those with TLE secondary to a discrete temporal neocortical lesion (NL). The case histories, interictal EEG, seizure semiology, ictal EEG and postoperative outcome of 46 pathologically proven patients (31 MTS and 15 NL) were compared. A history of febrile convulsions (FC) was more common in MTS patients (58% versus 26%, P < 0.05), as was a history of a significant cerebral event at < 4 years of age (22% versus 0%, P < 0.05). There were no statistically significant differences in the incidence or nature of auras. No statistically significant differences between the groups were found in the interictal-EEG. With ictal semiology dystonic posturing occurred more frequently in MTS patients (mean 52% versus 26%, P < 0.05). Facial grimacing/ twitching occurred earlier in the seizures of NL patients (median 19 s versus 35 s, P < 0.05). There was an increased frequency of fast rhythmic sharp waves (> 4 Hz) in the ictal-EEG of MTS patients (mean 81% versus 60%, P = 0.05). The patients with NL developed bilateral ictal EEG changes more often (mean 55% versus 26%, P < 0.05) and more rapidly (mean 23 s versus 74 s, P < 0.005). The onset of ictal EEG seizure activity was bilateral more often in patients with NL (20% versus 4%, P < 0.005). There were no significant differences between the two groups for any of the video-EEG features, in terms of whether or not the feature occurred at least once in an individual patients. There was a tendency for MTS patients to have a higher seizure-free postsurgical outcome (87% versus 60%, P = 0.057). However, all the NL patients who were not free of seizures had had an incomplete lesion resection. We conclude that there are a number of clinico-electrical differences between patients with mesial TLE (MTLE) and patients with neocortical TLE (NCTLE), but that none of these are sufficient to allow a distinction to be made in an individual patient.

Seizure frequency and duration of epilepsy are not risk factors for postoperative seizure outcome in patients with hippocampal sclerosis

PURPOSE

Despite accurate localization of the seizure focus, not all patients are seizure free after temporal lobectomy. This study determined risk factors for seizure recurrence in patients with proven hippocampal sclerosis.

METHODS

The outcome from surgery was assessed in 56 consecutive patients with proven hippocampal sclerosis. The age at surgery, duration of epilepsy, history and age of febrile seizures, age of onset of epilepsy, sex ratio, laterality of seizure focus, and seizure frequency were compared between patients seizure free and those not seizure free, and those seizure and aura free and those with seizure recurrence including auras.

RESULTS

During a mean follow-up of 38 months, 48 (86%) of 56 are seizure free. The mean age at surgery (37 vs. 36 years), duration of epilepsy (26 vs. 22 years), age (1.6 vs. 1.1 years), and occurrence (58 vs. 75%) of febrile seizures, age of onset of epilepsy (11 vs. 14 years), sex ratio (50 vs. 75% female), laterality of seizure focus (42 vs. 50% left), greater than weekly seizures (40 vs. 38%), and a history of (69 vs. 75%) and frequency of (2.10 vs. 2.38 per year) secondarily generalized seizures did not differ significantly between the two groups. Similarly there was no significant difference between patients seizure and aura free and those with seizure recurrence including auras.

CONCLUSIONS

Clinical factors such as seizure frequency and duration of epilepsy are not risk factors for postoperative seizure recurrence.

Non-invasive investigations successfully select patients for temporal lobe surgery

OBJECTIVES

There is controversy regarding the need for invasive monitoring in the preoperative assessment of patients with temporal lobe epilepsy. The use of a series of non-invasive investigations in identifying the seizure focus is reported in 75 consecutive adults referred for epilepsy surgery.

METHODS

All had video-EEG monitoring using scalp electrodes, high resolution MRI, and neuropsychology assessment. Other investigations included volumetric MRI, PET, and ictal and interictal SPECT. The seizure focus was localised and surgery offered if MRI disclosed unilateral hippocampal atrophy or a foreign tissue lesion and other investigations were either concordant or not discordant.

RESULTS

In 68 patients the seizure focus was localised and three patients were inoperable. Sixty five patients have been offered surgery and 50 have undergone temporal lobe surgery and have a follow up of at least 12 months (mean 24 months). All had pathology: hippocampal sclerosis 34, dysembryoblastic neuroepithelial tumour six, cavernoma four, dysplasia two, low grade glioma two, ganglioglioma two. Thirty nine patients (78%) are seizure free postoperatively, 29/34 with hippocampal sclerosis and 10/16 with a foreign tissue lesion. Of the 11 patients with postoperative recurrent seizures, eight have a >90% reduction in seizure frequency and three have <90% reduction in seizure frequency but a worthwhile improvement.

CONCLUSIONS

Non-invasive investigations successfully select most patients for temporal lobe surgery.

Hand hygiene in hospitals: anatomy of a revolution

Healthcare-associated infections (HAIs) affect hundreds of millions of individuals worldwide. Performing hand hygiene is widely accepted as a key strategy of infection prevention and control (IPC) to prevent HAIs, as healthcare workers' contaminated hands are the vehicle most often implicated in the cross-transmission of pathogens in health care. Over the last 20 years, a paradigm shift has occurred in hand hygiene: the change from handwashing with soap and water to using alcohol-based hand rubs. In order to put this revolution into context and understand how such a change was able to be implemented across so many different cultures and geographic regions, it is useful to understand how the idea of hygiene in general, and hand hygiene specifically, developed. This paper aims to examine how ideas about hygiene and hand hygiene evolved from ancient to modern times, from a ubiquitous but local set of ideas to a global phenomenon. It reviews historical landmarks from the first known documented recipe for soap by the Babylon civilization to the discovery of chlorine, and significant contributions by pioneers such as Antoine Germain Labarraque, Alexander Gordon, Oliver Wendell Holmes, Ignaz Philip Semmelweis, Louis Pasteur and Joseph Lister. It recalls that handwashing with soap and water appeared in guidelines to prevent HAIs in the 1980s; describes why alcohol-based hand rub replaced this as the central tool for action within a multi-modal improvement strategy; and looks at how the World Health Organization and other committed stakeholders, governments and dedicated IPC staff are championing hand hygiene globally.

Global hand hygiene improvement progress: two surveys using the WHO Hand Hygiene Self-Assessment Framework

The World Health Organization (WHO) conducted two global surveys in 2011 and 2015 using the Hand Hygiene Self-Assessment Framework. In 2011, 2119 health facilities from 69 countries participated, and in 2015, 807 health facilities from 91 countries participated. In total, 86 facilities submitted results for both surveys; their overall score increased significantly (P<0.001) from 335.1 [standard deviation (SD) 7.5] to 374.4 (SD 90.5). In terms of WHO regions, the scores for the Eastern Mediterranean, Europe and Western Pacific regions all improved significantly (P<0.01). This represents a snapshot of the current position of global hand hygiene improvement efforts, outlining facility progress and highlighting the value of such an assessment tool.

Prevention and control of health care-associated infections through improved hand hygiene

Determined actions are required to address the burden due to health care-associated infections worldwide and improve patient safety. Improving hand hygiene among health care workers is an essential intervention to achieve these goals. The World Health Organization (WHO) First Global Patient Safety Challenge, Clean Care is Safer Care, pledged to tackle the problem of health care-associated infection at its launch in 2005 and has elaborated a comprehensive set of guidelines for use in both developed and developing countries worldwide. The final version of the WHO Guidelines on Hand Hygiene in Health Care was issued in March 2009 and includes recommendations on indications, techniques, and products for hand hygiene. In this review, we discuss the role of hands in the transmission of health care-associated infection, the benefits of improved compliance with hand hygiene, and the recommendations, implementation strategies and tools recommended by WHO. We also stress the need for action to increase the pace with which these recommendations are implemented in facilities across India.

Early spectra of the gravitational wave source GW170817: Evolution of a neutron star merger

On 17 August 2017, Swope Supernova Survey 2017a (SSS17a) was discovered as the optical counterpart of the binary neutron star gravitational wave event GW170817. We report time-series spectroscopy of SSS17a from 11.75 hours until 8.5 days after the merger. Over the first hour of observations, the ejecta rapidly expanded and cooled. Applying blackbody fits to the spectra, we measured the photosphere cooling from [Formula: see text] to [Formula: see text] kelvin, and determined a photospheric velocity of roughly 30% of the speed of light. The spectra of SSS17a began displaying broad features after 1.46 days and evolved qualitatively over each subsequent day, with distinct blue (early-time) and red (late-time) components. The late-time component is consistent with theoretical models of r-process-enriched neutron star ejecta, whereas the blue component requires high-velocity, lanthanide-free material.

The assessment and treatment of concerns and anxiety in patients undergoing presurgical monitoring for epilepsy

PURPOSE

This study investigated the impact of a treatment information package on patients being monitored for possible surgical treatment for temporal lobe epilepsy.

METHODS

One hundred patients were randomly assigned to either a high- or low-information preparation condition. Levels of anxiety were tested soon after admission by using the Hospital Anxiety and Depression Scale (HADS), The State-Trait Anxiety Inventory (STAI), and a newly devised questionnaire to assess specific concerns and anxieties of epilepsy patients presenting for monitoring and surgery, the Concerns About Epilepsy Monitoring Questionnaire (CAEMQ). Dispositional desire for information was assessed by the Miller Behavioural Style Scale (MBSS) to investigate whether coping disposition affected coping styles in the hospital setting. Patients assigned to the high-information condition were exposed to an intervention package, which included viewing a video depicting two separate interviews with patients who had undergone surgery as well as an information package, which described the various tests that the patient would undergo in the course of the monitoring procedure. Patients assigned to the low-information group were given information that the hospital provided to all patients in their care. All subjects were then retested on anxiety levels a few days later.

RESULTS

Those in the high-information group showed a significant decrease in anxiety and depression levels compared with those in the low-information group.

CONCLUSIONS

Within the main findings, an effect of dispositional style was found. Identification as either a monitor or blunter on the MBSS showed different coping strategies on arrival in hospital as measured by the CAEMQ, indicating that the level of information given to patients with epilepsy on arrival needs to be mediated by awareness of these two dispositional styles so that they obtain maximal benefit from the information to which patients with epilepsy are exposed.

Electromagnetic evidence that SSS17a is the result of a binary neutron star merger

Eleven hours after the detection of gravitational wave source GW170817 by the Laser Interferometer Gravitational-Wave Observatory and Virgo Interferometers, an associated optical transient, SSS17a, was identified in the galaxy NGC 4993. Although the gravitational wave data indicate that GW170817 is consistent with the merger of two compact objects, the electromagnetic observations provide independent constraints on the nature of that system. We synthesize the optical to near-infrared photometry and spectroscopy of SSS17a collected by the One-Meter Two-Hemisphere collaboration, finding that SSS17a is unlike other known transients. The source is best described by theoretical models of a kilonova consisting of radioactive elements produced by rapid neutron capture (the r-process). We conclude that SSS17a was the result of a binary neutron star merger, reinforcing the gravitational wave result.

Identical twins with Alzheimer's disease

Genetically proven identical twin sisters with Alzheimer's disease are reported. Both sisters at the age of fifty years developed a dementing illness. Their mother and maternal grandmother developed at the same age a similar illness. It is suggested that in some cases of familial Alzheimer's disease the condition is inherited by a single mutant gene.

Computed tomography of rhinocerebral mucormycosis

Rhinocerebral mucormycosis is a rare fungal infection which is frequently fatal. Survival depends on early diagnosis and immediate aggressive treatment. Previously described radiological changes have been non-specific. The CT features of two cases are described. Non-enhancement of the superior ophthalmic vein and ophthalmic artery appears to be a CT sign specific to this disease.

Reversal of a neurologic paraneoplastic syndrome with octreotide (Sandostatin) in a patient with glucagonoma

A 69-year-old woman with classic glucagonoma syndrome had associated progressive neurologic disease manifest as dementia, ataxia, optic atrophy, and lower limb weakness. Visual evoked responses (VERs) were absent bilaterally. After an attempt at resection was unsuccessful, therapy was started with somatostatin analogue (Sandostatin, SMS 201-995). Over the ensuing 3 months, there was a decrease in the plasma glucagon level, resolution of the rash, weight gain, reversal of the dementia, and an improvement in coordination and limb weakness. Subsequent VERs revealed bilateral delayed responses.

AUStralian study of titration to effect profile of safety (AUS-STEPS): high-dose gabapentin (neurontin) in partial seizures

PURPOSE

To evaluate the safety, tolerability, efficacy, and impact on quality of life of gabapentin (Neurontin; GBP) as adjunctive therapy in patients with refractory partial seizures.

METHODS

AUS-STEPS was an open-label, multicenter, prospective study in patients experiencing partial seizures who were inadequately controlled with one to three concurrent antiepileptic drugs (AEDs). GBP treatment was titrated to a maximum of 4,800 mg/day, over a treatment period of 24 weeks, to achieve an efficacious and tolerable dosage. Efficacy was assessed by seizure-frequency data. Quality of life was evaluated by using the QOLIE-10 questionnaire, and safety was assessed by adverse-event reports and clinical laboratory findings.

RESULTS

A total of 176 patients received treatment with GBP, with 174 evaluable for intention-to-treat (ITT) efficacy analysis. A reduction of >50% in overall seizure frequency was observed in 93 patients (53%). There was a small (4.6%) overall improvement in QOLIE-10 score. The most frequent adverse events were dizziness (31%), fatigue (29%), somnolence (27%), headache (21%), and ataxia (20%), with no major increase seen in adverse events necessitating discontinuation as the dose of GBP was titrated upward.

CONCLUSIONS

This study indicates that patients with partial epilepsy may be effectively treated with GBP at dosages of < or =4,800 mg/day, without altering the safety profile of the drug.

Epilepsy and primary cerebral tumours

Although the association of epilepsy with cerebral tumours is well recognized, the reported incidence of seizures and relationship to tumour pathology varies significantly. This study assessed retrospectively the incidence of seizures, relationship to tumour pathology, natural history of epilepsy and prognostic significance of presentation with a seizure in 120 consecutive adults with histologically proven primary cerebral hemisphere tumours including meningiomas. 52% had a seizure and most were at presentation. Seizures were more common with anaplastic astrocytoma (AA) (18 23 ) than glioblastoma multiforme (21 56 ) (p = 0.001) and seizure occurrence was associated with cortical invasion. 52% of meningioma patients had a seizure. Seizures recurred in 34%, more frequently with glioma (19 of 46) than meningioma (1 of 15) (p < 0.05). Patients with AA presenting with a seizure had a longer survival (28 months) than patients without seizure (8 months) (p = 0.05 one sided). In conclusion, seizures are a common complication of cerebral tumours, usually at presentation and correlate with tumour pathology. A seizure at presentation in AA correlates with longer survival.

Imaging in epilepsy

Neuroimaging in epilepsy now includes magnetic resonance imaging, positron emission tomography (PET), single-photon emission tomography (SPECT), magnetoencephalography, and magnetic resonance spectroscopy. Recent advances in neuroimaging include improved rates of detection of lesions on structural imaging using quantitative methods, identification of metabolic patterns on functional imaging with PET, and recognition of the value of ictal SPECT in seizure localization.

Forearm arterial vascular responsiveness in insulin-dependent diabetic subjects

The vascular reactivity of forearm arterioles was measured in 16 control subjects (C) and 30 insulin-dependent diabetic (IDDM) subjects, 16 of whom were shown to have microvascular and/or neuropathic complications (DC) including 8 with autonomic neuropathy (DCa) and 14 were shown to be free of complications (DNC). Forearm blood flow was measured by strain gauge plethysmography basally, following a cold pressor stress and following a period of arterial occlusion (reactive hyperaemia). The tests were repeated 24 h later following aspirin treatment. Both C and DNC showed a significant reduction in blood flow in the cold pressor test (C 0.64 +/- 0.12, DNC 0.89 +/- 0.22 ml/100 ml forearm tissue/min reduction in flow P < 0.005), while DC showed no significant response. Reactive hyperaemia was significantly greater in C than in DNC or DC (8.37 +/- 1.14, 5.51 +/- 1.27 and 4.95 +/- 0.75 ml/100 ml tissue/min, respectively, P < 0.02). In the DC group, DCa had significantly less response than those without autonomic neuropathy. Aspirin treatment restored the response of DNC but not DC to normal, suggesting that the abnormality in the former group may have been due to overproduction of a vasoconstrictive cyclooxygenase product (such as thromboxane A2). It is concluded that the abnormalities of vasomotor responses in diabetic subjects are complex and are apparently dependent on autonomic neuropathy, humoral and perhaps structural changes.

A lanthanide-rich kilonova in the aftermath of a long gamma-ray burst

Observationally, kilonovae are astrophysical transients powered by the radioactive decay of nuclei heavier than iron, thought to be synthesized in the merger of two compact objects1-4. Over the first few days, the kilonova evolution is dominated by a large number of radioactive isotopes contributing to the heating rate2,5. On timescales of weeks to months, its behaviour is predicted to differ depending on the ejecta composition and the merger remnant6-8. Previous work has shown that the kilonova associated with gamma-ray burst 230307A is similar to kilonova AT2017gfo (ref. 9), and mid-infrared spectra revealed an emission line at 2.15 micrometres that was attributed to tellurium. Here we report a multi-wavelength analysis, including publicly available James Webb Space Telescope data9 and our own Hubble Space Telescope data, for the same gamma-ray burst. We model its evolution up to two months after the burst and show that, at these late times, the recession of the photospheric radius and the rapidly decaying bolometric luminosity (Lbol ∝ t-2.7±0.4, where t is time) support the recombination of lanthanide-rich ejecta as they cool.