Proper-motion age dating of the progeny of Nova Scorpii AD 1437.

'Cataclysmic variables' are binary star systems in which one star of the pair is a white dwarf, and which often generate bright and energetic stellar outbursts. Classical novae are one type of outburst: when the white dwarf accretes enough matter from its companion, the resulting hydrogen-rich atmospheric envelope can host a runaway thermonuclear reaction that generates a rapid brightening. Achieving peak luminosities of up to one million times that of the Sun, all classical novae are recurrent, on timescales of months to millennia. During the century before and after an eruption, the 'novalike' binary systems that give rise to classical novae exhibit high rates of mass transfer to their white dwarfs. Another type of outburst is the dwarf nova: these occur in binaries that have stellar masses and periods indistinguishable from those of novalikes but much lower mass-transfer rates, when accretion-disk instabilities drop matter onto the white dwarfs. The co-existence at the same orbital period of novalike binaries and dwarf novae-which are identical but for their widely varying accretion rates-has been a longstanding puzzle. Here we report the recovery of the binary star underlying the classical nova eruption of 11 March AD 1437 (refs 12, 13), and independently confirm its age by proper-motion dating. We show that, almost 500 years after a classical-nova event, the system exhibited dwarf-nova eruptions. The three other oldest recovered classical novae display nova shells, but lack firm post-eruption ages, and are also dwarf novae at present. We conclude that many old novae become dwarf novae for part of the millennia between successive nova eruptions.

Simplified biplanar (0-90°) fluoroscopic puncture technique for percutaneous nephrolithotomy: the learning curve.

PURPOSE: To evaluate the learning curve of the simplified fluoroscopic biplanar (0-90º) puncture technique for percutaneous nephrolithotomy. METHODS: We prospectively evaluated patients with renal stones treated with percutaneous nephrolithotomy by a single institution's fellows employing the simplified bi-planar (0-90º) fluoroscopic puncture technique for renal access. The learning curve was assessed with the fluoroscopic screening time and the percutaneous renal puncture time. Data obtained were compared to a subset of patients operated by a senior surgeon. RESULTS: Eighty-nine patients were included in the study. Forty patients were operated by fellow-1, 39 by fellow-2, and 10 patients by the senior surgeon. Demographic data of all patients between groups were homogeneous, with no difference in gender (p = 0.432), age (p = 0.92), stone volume (p = 0.78), puncture laterality (p = 0.755), and body mass index (p = 0.365). The mean puncture time was 7.5, 4, and 3.1 min for fellow-1, fellow-2, and expert, respectively. The mean fluoroscopic screening time for the puncture was 10, 11, and 5.1 s for fellow-1, fellow-2, and the expert, respectively. Stone cases, both fellows needed to complete 10 procedures to match the senior surgeon in the mean puncture time (p = 0.046); meanwhile, the fluoroscopic screening time was equal even before to complete 10 procedures. CONCLUSION: This study suggests that with the simplified biplanar (0-90º) puncture technique, the fluoroscopic screening time used in the learning process is brief. A novice fellow could require to complete ten cases to flatten the learning curve treating complex stone cases, and a flat learning curve is seen since the beginning when treating simple renal stones.

Status epilepticus without impairment of consciousness: Long-term outcomes according to duration.

OBJECTIVE: The point after which non-convulsive status epilepticus (NCSE) can cause permanent damage remains to be elucidated. The aim of this study was to analyze the association between time to resolution and long-term outcomes in NCSE. METHODS: We performed a retrospective study of all patients with focal NCSE without consciousness impairment at two tertiary care hospitals in Spain. All the data were registered prospectively and the study period was December 2014-May 2018. We collected information on demographics, SE etiology, time to administration of different lines of treatment, time to NCSE resolution, and outcomes at discharge, 1 year, and 4 years. Clinical outcome was prospectively categorized as good (return to baseline function) or poor (new disability and death). RESULTS: Seventy-four patients with a mean (±SD) age of 63.4 ±â€¯17.5 years and a mean follow-up time of 2.4 ±â€¯2.2 years were studied. A poor outcome at discharge was associated with a potentially fatal etiology (p < 0.001), EMSE score (Epidemiology-based Mortality Score in Status Epilepticus) (p = 0.012), lateral periodic discharges on EEG (p = 0.034), and occurrence of major complications during hospitalization (p = 0.007). An SE duration of >100 h was clearly associated with a worse outcome (p < 0.001). In the multiple regression analysis, the only independent predictors of a poor outcome at discharge were an SE duration of >+100 hours (p = 0.001), a potentially fatal etiology (p = 0.001), and complications during hospitalization (p = 0.010). An SE duration of >100 hours retained its value as the optimal cutoff point for predicting poor outcomes at both 1 year (p = 0.037) and 4 years (p = 0.05). Other predictors of poor long-term outcomes were a potentially fatal etiology (p < 0.001) and EMSE score (p = 0.034) at 1 year, and progressive symptomatic etiology at 4 years (p = 0.025). SIGNIFICANCE: In patients with focal NCSE without consciousness impairment, a potentially fatal etiology and an SE duration of >100 h were associated with poor short-term and long-term outcomes.

Indoor radon exposure and excess of lung cancer mortality: the case of Mexico-an ecological study.

Radon is a radioactive gas that can migrate from soils and rocks and accumulate in indoor areas such as dwellings and buildings. Many studies have shown a strong association between the exposure to radon, and its decay products, and lung cancer (LC), particularly in miners. In Mexico, according to published surveys, there is evidence of radon exposure in large groups of the population, nevertheless, only few attention has been paid to its association as a risk factor for LC. The aim of this ecological study is to evaluate the excess risk of lung cancer mortality in Mexico due to indoor radon exposure. Mean radon levels per state of the Country were obtained from different publications and lung cancer mortality was obtained from the National Institute of Statistics, Geography and Informatics for the period 2001-2013. A model proposed by the International Commission on Radiological Protection to estimate the annual excess risk of LC mortality (per 105 inhabitants) per dose unit of radon was used. The average indoor radon concentrations found rank from 51 to 1863 Bq m-3, the higher average dose exposure found was 3.13 mSv year-1 in the north of the country (Chihuahua) and the mortality excess of LC cases found in the country was 10 ± 1.5 (range 1-235 deaths) per 105 inhabitants. The highest values were found mainly in the Northern part of the country, where numerous uranium deposits are found, followed by Mexico City, the most crowded and most air polluted area in the country. A positive correlation (r = 0.98 p < 0.0001) was found between the excess of LC cases and the dose of radon exposure. Although the excess risk of LC mortality associated with indoor radon found in this study was relatively low, further studies are needed in order to accurately establish its magnitude in the country.

Clinical Predictive Model of Multidrug Resistance in Neutropenic Cancer Patients with Bloodstream Infection Due to Pseudomonas aeruginosa.

We aimed to assess the rate and predictive factors of bloodstream infection (BSI) due to multidrug-resistant (MDR) Pseudomonas aeruginosa in neutropenic cancer patients. We performed a multicenter, retrospective cohort study including oncohematological neutropenic patients with BSI due to P. aeruginosa conducted across 34 centers in 12 countries from January 2006 to May 2018. A mixed logistic regression model was used to estimate a model to predict the multidrug resistance of the causative pathogens. Of a total of 1,217 episodes of BSI due to P. aeruginosa, 309 episodes (25.4%) were caused by MDR strains. The rate of multidrug resistance increased significantly over the study period (P = 0.033). Predictors of MDR P. aeruginosa BSI were prior therapy with piperacillin-tazobactam (odds ratio [OR], 3.48; 95% confidence interval [CI], 2.29 to 5.30), prior antipseudomonal carbapenem use (OR, 2.53; 95% CI, 1.65 to 3.87), fluoroquinolone prophylaxis (OR, 2.99; 95% CI, 1.92 to 4.64), underlying hematological disease (OR, 2.09; 95% CI, 1.26 to 3.44), and the presence of a urinary catheter (OR, 2.54; 95% CI, 1.65 to 3.91), whereas older age (OR, 0.98; 95% CI, 0.97 to 0.99) was found to be protective. Our prediction model achieves good discrimination and calibration, thereby identifying neutropenic patients at higher risk of BSI due to MDR P. aeruginosa The application of this model using a web-based calculator may be a simple strategy to identify high-risk patients who may benefit from the early administration of broad-spectrum antibiotic coverage against MDR strains according to the local susceptibility patterns, thus avoiding the use of broad-spectrum antibiotics in patients at a low risk of resistance development.

[Arrival times of patients with stroke to a public hospital]. / Tiempos de llegada de pacientes con ataque cerebrovascular en un hospital regional de alta complejidad.

BACKGROUND: Stroke is a time-dependent emergency. Most patients with acute ischemic stroke are excluded from reperfusion therapies due to late consultation. AIMS: To estimate the arrival times of patients with stroke to the Emergency Room (ER) of a public hospital. To identify factors associated with early consultation. MATERIAL AND METHODS: A convenience sample, 583 patients aged 71 ± 13 years (55% males) consulting for stroke at an emergency room was analyzed in terms of delay between onset of symptoms and arrival to the ER, demographics and etiology of stroke. RESULTS: The admission diagnoses were ischemic stroke in 76%, intracerebral hemorrhage in 12%, transient ischemic attack in 9% and subarachnoid hemorrhage in 3%. The median time of arrival was 8 hours and 11 minutes after the onset of symptoms. Nineteen percent of consultations for ischemic stroke occurred within 3 hours of symptom onset, and 38% within 6 hours. In the logistic regression analysis, having an address near the hospital and the severity of stroke were associated with early consultation with a combined odds ratio of 5.97 (95% confidence intervals 3.23-11.04). CONCLUSIONS: There were significant differences in the arrival times of patients with stroke. Only a low proportion of patients with ischemic stroke consulted within the window for reperfusion therapies. Severe strokes and living near the hospital were associated with early consultation.

Prevalence of functional gastrointestinal disorders in adults with systemic lupus erythematosus.

Objective (a) to assess the prevalence of functional gastrointestinal disorders (FGIDs) in female Mexican systemic lupus erythematosus (SLE) patients using the Rome III criteria and (b) to examine the effect of disease duration on FGID prevalence. Methods Female SLE outpatients aged ≥18 years with no organic gastrointestinal disorder were included. Participants were invited to upper gastrointestinal endoscopy screening and a faecal immunochemical test. FGID symptoms were evaluated using the Rome III questionnaire. Results Eighty-six SLE patients with median age of 45 (interquartile range 34-54) years were included. At least one FGID was found in 76.7% (66/88) of patients with SLE. The most prevalent domains of FGID diagnosed were functional oesophageal, gastroduodenal disorders and bowel disorders, of which functional dyspepsia (72.7%), functional heartburn (68.1%) and bloating (63.8%) were the most frequent. Fifty-nine per cent of patients had overlapping FGIDs. The most prevalent overlap was the combination of functional dyspepsia and functional heartburn. Patients with longer disease duration had a higher prevalence of FGID than those with shorter disease duration. Conclusions There was a high prevalence of FGIDs in Mexican SLE women with low disease activity. Overlapping FGIDs were frequent. Longer disease duration may be associated with FGIDs in SLE patients.

Factors of the epidemiological triad that influence the persistence of human papilloma virus infection in women with systemic lupus erythematosus.

We studied the epidemiologic triad-related factors influencing human papilloma virus (HPV) persistence in Mexican women with systemic lupus erythematosus (SLE). Patients aged ≥18 years with SLE (American College of Rheumatology criteria), with and without HPV persistence, were selected. Groups were analyzed by (1) host: clinical disease characteristics; (2) agent: (I) infectious (prevalence, incidence, HPV genotype and co-infections (≥2 HPV genotypes or mycoplasmas)), (II) chemical (contraceptives and immunosuppressive drugs) and (III) physical (vitamin D deficiency) and (3) environment. A total of 121 SLE patients were selected over a two-year period. (1) Host: mean age 45.8 years and disease duration 12.7 years. (2) Agent: (I) infectious. HPV infection prevalence in the second sample was 26.4%, high-risk HPV genotypes 21.5% and co-infections 7.4%. HPV infection incidence was 13.2%, persistence 13.2% and clearance 15.7%. (II) Chemical: use of oral hormonal contraceptives 5% and immunosuppressive treatment 97.5%. (III) Physical: Vitamin D levels were similar in both groups. (3) Environment: (I) natural. A total of 60.6% of patients were residents of Puebla City. (II) Social: The mean education level was 10.9. Poverty levels were: III degree 52.4%, IV degree 28% and II degree 17%. (III) Cultural behavioral: Onset of sexual life was 20.5 years, 10% had ≥3 sexual partners and 51.2% were postmenopausal. In conclusion, no factor of the epidemiologic triad was associated with HPV infection prevalence.

The anti-thrombotic effects of vitamin D and their possible relationship with antiphospholipid syndrome.

The importance of the immunomodulatory effects of vitamin D has recently been associated with autoimmune and chronic inflammatory diseases. Vitamin D deficiency has been linked to the development of autoimmune conditions. Antiphospholipid syndrome is an autoimmune disease characterized by thrombotic events and obstetric complications in patients with antiphospholipid antibodies. Current data show that patients with antiphospholipid syndrome have a high prevalence of vitamin D deficiency even without classic risk factors. Several studies have suggested vitamin D may have anti-thrombotic functions. In antiphospholipid syndrome, low vitamin D serum levels have been associated with thrombotic manifestations, suggesting a possible protective role of vitamin D in antiphospholipid syndrome. This literature review presents current evidence on the haemostatic functions of vitamin D and their possible relationship with the clinical manifestations of antiphospholipid syndrome.

Specificity of electroclinical features in the diagnosis of ring chromosome 20.

BACKGROUND: Ring chromosome 20 (R20) syndrome is a chromosomal disorder characterized mainly by drug-resistant frontal lobe seizures, recurrent nonconvulsive status epilepticus (NCSE), and typical EEG features. The aim of this study was to investigate if this triad is common and specific to all patients with R20. METHODS: In this cross-sectional study (from 2000 to 2011), we selected patients who fulfilled at least two out of three criteria: drug-resistant frontal lobe seizures, recurrent NCSE, and characteristic electroencephalography (EEG) features. In all patients, diagnosis was based on karyotype analysis of at least 100 metaphases. RESULTS: We identified 36 patients who met at least two of the selected criteria: six patients (16.7%) with R20 and 30 (83.3%) without R20 (non-R20). All patients with R20 met all three criteria. Eleven (36.7%) patients without R20, however, also displayed the full triad. In 19 patients without R20 (63.3%), one of the three clinical features was missing: frontal lobe seizures were not resistant to antiepileptic drugs (AED) in four (13.3%), recurrent NCSE was missing in six (20%), and nine (30%) patients did not have typical EEG features. Based on this data, specificity was 63.3%, positive predictive value was 35.3%, and sensitivity and negative predictive values were 100%. Additionally, a review of all publications describing the R20 phenotype revealed that 81.98% of patients with R20 display the full electroclinical triad. CONCLUSIONS: In our study, all patients with R20 displayed the three electroclinical characteristics. This is in line with previous reports (presenting high sensitivity and negative predictive value). However, these features can also be observed in other epilepsies and are not specific to R20. Our findings suggest that in the presence of the full triad of symptoms, karyotype analysis focused on chromosome 20 should be conducted.

[Waiting times for neurological emergencies in an emergency room]. / Tiempos de atención de urgencias neurológicas en un hospital regional de alta complejidad.

BACKGROUND: Neurological emergencies constitute 10-15% of medical emergencies. Doctor Hernán Henríquez Aravena Hospital has in house neurologists present permanently at the Emergency Room since July 2013. AIM: To estimate the waiting times for neurological consultations; to compare the waiting times between neurovascular (UV) and non-vascular (UNV) emergencies; and to compare the waiting times of two prioritization (triage) models. MATERIAL AND METHODS: A convenience sample of the consultations made during shift # 1 at the emergency room between January and December 2016, was analyzed. RESULTS: There were 859 consultations in the period, 570 for UNV and 289 for UV. Mean age of consultants was 57 years and 52% were women. The median time for having an evaluation by a neurologist was 106 min (132 and 81 min for UNV and UV respectively). Twenty seven percent of patients were evaluated in less than one hour (23 and 36% of UNV and UV, respectively). The change of the prioritization model decreased the waiting time by 81 and 32 min for UNV and UV, respectively. CONCLUSIONS: There were significant differences in waiting times between neurovascular and non-vascular emergencies. Most patients were not evaluated in less than 60 minutes. The change in the initial stratification model was associated with a significant reduction in the waiting times for neurological emergencies.

Incidence of cervical human papillomavirus infection in systemic lupus erythematosus women.

Objectives Our objective was to study the incidence, persistence and clearance of human papillomavirus infection in systemic lupus erythematosus women and assess risk factors for persistence of human papillomavirus infection. Methods We carried out a prospective, observational cohort study of 127 systemic lupus erythematosus women. Patients were evaluated at baseline and at three years. Traditional and systemic lupus erythematosus women-related disease risk factors were collected. Gynaecological evaluations and cervical cytology screening were made. Human papillomavirus detection and genotyping were made by polymerase chain reaction and linear array. Results The cumulative prevalence of human papillomavirus infection increased from 22.8% at baseline to 33.8% at three years; p = < 0.001: 20.1% of patients experienced 43 incident infections. The risk of any human papillomavirus infection was 10.1 per 1000 patient-months. At three years, 47 (88.6%) prevalent infections were cleared. Independent risk factors associated with incident human papillomavirus infection included more lifetime sexual partners (odds ratio = 1.8, 95% confidence interval = 1.11-3.0) and cumulative cyclophosphamide dose (odds ratio = 3.9, 95% confidence interval = 1.2-12.8). Conclusions In systemic lupus erythematosus women, the cumulative prevalence of human papillomavirus infection, including high risk-human papillomavirus and multiple human papillomavirus infections, may increase over time. Most persistent infections were low risk-human papillomavirus. The number of lifetime sexual partners and the cumulative cyclophosphamide dose were independently associated with incident human papillomavirus infection.

Pathogen-related factors affecting outcome of catheter-related bacteremia due to methicillin-susceptible Staphylococcus aureus in a Spanish multicenter study.

Even with appropriate clinical management, complicated methicillin-susceptible Staphylococcus aureus (MSSA) catheter-related bacteremia (CRB) is frequent. We investigated the influence of molecular characteristics of MSSA strains on the risk of complicated bacteremia (CB) in MSSA-CRB. A multicenter prospective study was conducted in Spain between 2011 and 2014 on MSSA-CRB. Optimized protocol-guided clinical management was required. CB included endocarditis, septic thrombophlebitis, persistent bacteremia and/or end-organ hematogenous spread. Molecular typing, agr functionality and DNA microarray analysis of virulence factors were performed in all MSSA isolates. Out of 83 MSSA-CRB episodes included, 26 (31.3%) developed CB. MSSA isolates belonged to 16 clonal complexes (CCs), with CC30 (32.5%), CC5 (15.7%) and CC45 (13.3) being the most common. Comparison between MSSA isolates in episodes with or without CB revealed no differences regarding agr type and functionality. However, our results showed that CC15 and the presence of genes like cna, chp and cap8 were associated with the development of CB. The multivariate analysis highlighted that the presence of cna (Hazard ratio 2.9; 95% CI 1.14-7.6) was associated with the development of CB. Our results suggest that particular CCs and specific genes may influence the outcome of MSSA-CRB.

Experimental Study of Anisotropic Stress/Strain Relationships of Aortic and Pulmonary Artery Homografts and Synthetic Vascular Grafts.

Homografts and synthetic grafts are used in surgery for congenital heart disease (CHD). Determining these materials' mechanical properties will aid in understanding tissue behavior when subjected to abnormal CHD hemodynamics. Homograft tissue samples from anterior/posterior aspects, of ascending/descending aorta (AA, DA), innominate artery (IA), left subclavian artery (LScA), left common carotid artery (LCCA), main/left/right pulmonary artery (MPA, LPA, RPA), and synthetic vascular grafts, were obtained in three orientations: circumferential, diagonal (45 deg relative to circumferential direction), and longitudinal. Samples were subjected to uniaxial tensile testing (UTT). True strain-Cauchy stress curves were individually fitted for each orientation to calibrate Fung model. Then, they were used to calibrate anisotropic Holzapfel-Gasser model (R2 > 0.95). Most samples demonstrated a nonlinear hyperelastic strain-stress response to UTT. Stiffness (measured by tangent modulus at different strains) in all orientations were compared and shown as contour plots. For each vessel segment at all strain levels, stiffness was not significantly different among aspects and orientations. For synthetic grafts, stiffness was significantly different among orientations (p < 0.042). Aorta is significantly stiffer than pulmonary artery at 10% strain, comparing all orientations, aspects, and regions (p = 0.0001). Synthetic grafts are significantly stiffer than aortic and pulmonary homografts at all strain levels (p < 0.046). Aortic, pulmonary artery, and synthetic grafts exhibit hyperelastic biomechanical behavior with anisotropic effect. Differences in mechanical properties among vascular grafts may affect native tissue behavior and ventricular/arterial mechanical coupling, and increase the risk of deformation due to abnormal CHD hemodynamics.

Automated early detection of drops in commercial egg production using neural networks.

1. The purpose of this work was to support decision-making in poultry farms by performing automatic early detection of anomalies in egg production. 2. Unprocessed data were collected from a commercial egg farm on a daily basis over 7 years. Records from a total of 24 flocks, each with approximately 20 000 laying hens, were studied. 3. Other similar works have required a prior feature extraction by a poultry expert, and this method is dependent on time and expert knowledge. 4. The present approach reduces the dependency on time and expert knowledge because of the automatic selection of relevant features and the use of artificial neural networks capable of cost-sensitive learning. 5. The optimum configuration of features and parameters in the proposed model was evaluated on unseen test data obtained by a repeated cross-validation technique. 6. The accuracy, sensitivity, specificity and positive predictive value are presented and discussed at 5 forecasting intervals. The accuracy of the proposed model was 0.9896 for the day before a problem occurs.

[Intravenous thrombolysis for acute ischemic stroke. A four years’ experience in a Chilean public hospital]. / Evolución del protocolo de trombolisis endovenosa en ataque cerebrovascular isquémico agudo.

BACKGROUND: Intravenous thrombolysis (IVT) with alteplase (tissue plasminogen activator) is the standard pharmacological treatment in acute ischemic stroke (AIS), reducing disability in patients. AIM: To report the results a thrombolysis protocol during four years in a regional public hospital. MATERIAL AND METHODS: Data from 106 consecutive patients aged 68 ± 13 years (57% men) who were treated with IVT, from May 2012 until April 2016, was analyzed. RESULTS: The median door-to-needle time was 80 minutes (interquartile range = 57-113). The median National Institute of Health Stroke Scale (NIHSS) scores on admission and at discharge were was 11.5 and 5 points respectively. At discharge, 27% of hospitalized patients had a favorable outcome (n = 99), defined as having 0 to 1 points in the modified Rankin scale. Symptomatic intracerebral hemorrhage and mortality rates were 5.7 and 13.1%, respectively. The thrombolysis rate rose from 0.7% in 2012 to 6% in 2016. CONCLUSIONS: The implementation of 24/7 neurology shifts in the Emergency Department allowed us to increase the amount and quality of IVT in our hospital, as measured by the rate of thrombolysis and by process indicators such as door-to-needle time.

Validity of the clinical and content scales of the Multiphasic Personality Inventory Minnesota 2 for the diagnosis of psychogenic non-epileptic seizures.

INTRODUCTION: The use of the Multiphasic Personality Inventory Minnesota 2 (MMPI-2) for the diagnosis of psychogenic non-epileptic seizures (PNES) is controversial. This study examines the validity of the clinical scales and, unlike previous works, the content scales. METHODS: Cross-sectional study of 209 patients treated in the epilepsy unit. We performed a logistic regression analysis, taking video-electroencephalography as the reference test, and as predictor variables age, sex, IQ and clinical (model A) or content scales (model B) of the MMPI-2. The models were selected according to the Aikake index and compared using the DeLong test. RESULTS: We analyzed 37 patients with PNES alone, or combined with seizures, and 172 patients with seizures only. The model consisting of sex, Hs (hypochondriasis) and Pa (paranoia) showed a sensitivity of 77.1%, a specificity of 76.8%, a percentage of correct classification of 76.8%, and an area under the curve (AUC) of 0.836 for diagnosing CNEP. Model B, consisting of sex, HEA (health concerns) and FRS (fears), showed a sensitivity of 65.7%, a specificity of 78.0%, a percentage of correct classification of 75.9% and an AUC of 0.840. DeLong's test did not detect significant differences. CONCLUSIONS: The MMPI-2 has a moderate validity for the diagnosis of PNES in patients referred to an epilepsy unit. Using content scales does not significantly improve results from the clinical scales.

The effect of Chrysoperla carnea (Neuroptera: Chrysopidae) and Adalia bipunctata (Coleoptera: Coccinellidae) on the spread of cucumber mosaic virus (CMV) by Aphis gossypii (Hemiptera: Aphididae).

The effects of two aphidophagous predators, the larvae of Chrysoperla carnea and adults of Adalia bipunctata, on the spread of cucumber mosaic virus (CMV) transmitted in a non-persistent manner by the cotton aphid Aphis gossypii were studied under semi-field conditions. Natural enemies and aphids were released inside insect-proof cages (1 m × 1 m × 1 m) with a central CMV-infected cucumber plant surrounded by 48 healthy cucumber seedlings, and the spatiotemporal dynamics of the virus and vector were evaluated in the short and long term (1 and 5 days) in the presence and absence of the natural enemy. The spatial analysis by distance indices methodology together with other indices measuring the dispersal around a single focus was used to assess the spatial pattern and the degree of association between the virus and its vector. Both natural enemies significantly reduced the number of aphids in the CMV-source plant after 5 days but not after 1 day. The CMV transmission rate was generally low, especially after 1 day, due to the limited movement of aphids from the central CMV-source plant, which increased slightly after 5 days. Infected plants were mainly located around the central virus-infected source plant, and the percentage of aphid occupation and CMV-infected plants did not differ significantly in absence and presence of natural enemies. The distribution patterns of A. gossypii and CMV were only coincident close to the central plant. The complexity of multitrophic interactions and the role of aphid predators in the spread of CMV are discussed.

Mathematical modeling of patient-specific ventricular assist device implantation to reduce particulate embolization rate to cerebral vessels.

Stroke is the most devastating complication after ventricular assist device (VAD) implantation, with an incidence of 14%-47% despite improvements in device design and anticoagulation. This complication continues to limit the widespread implementation of VAD therapy. Patient-specific computational fluid dynamics (CFD) analysis may elucidate ways to reduce this risk. A patient-specific three-dimensional model of the aortic arch was generated from computed tomography. A 12 mm VAD outflow-graft (VAD-OG) "anastomosed" to the aorta was rendered. CFD was applied to study blood flow patterns. Particle tracks, originating from the VAD, were computed with a Lagrangian phase model and percentage of particles entering the cerebral vessels was calculated. Twelve implantation configurations of the VAD-OG and three particle sizes (2, 4, and 5 mm) were considered. Percentage of particles entering the cerebral vessels ranged from 6% for the descending aorta VAD-OG anastomosis, to 14% for the ascending aorta at 90 deg VAD-OG anastomosis. Values were significantly different among all configurations (X(2) = 3925, p < 0.0001). Shallower and more cephalad anastomoses prevented formation of zones of recirculation in the ascending aorta. In this computational model and within the range of anatomic parameters considered, the percentage of particles entering the cerebral vessels from a VAD-OG is reduced by nearly 60% by optimizing outflow-graft configuration. Ascending aorta recirculation zones, which may be thrombogenic, can also be eliminated. CFD methods coupled with patient-specific anatomy may aid in identifying the optimal location and angle for VAD-OG anastomosis to minimize stroke risk.