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Sample records for intraventricular conduction delay

  1. Diphenhydramine Overdose with Intraventricular Conduction Delay Treated with Hypertonic Sodium Bicarbonate and IV Lipid Emulsion

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    Amin Abdi

    2014-11-01

    Full Text Available Diphenhydramine toxicity commonly manifests with antimuscarinic features, including dry mucous membranes, tachycardia, urinary retention, mydriasis, tachycardia, and encephalopathy. Severe toxicity can include seizures and intraventricular conduction delay. We present here a case of a 23-year-old male presenting with recurrent seizures, hypotension and wide complex tachycardia who had worsening toxicity despite treatment with sodium bicarbonate. The patient was ultimately treated with intravenous lipid emulsion therapy that was temporally associated with improvement in the QRS duration. We also review the current literature that supports lipid use in refractory diphenhydramine toxicity. [West J Emerg Med. 2014;15(7:–0.

  2. HEREDITARY INTRAVENTRICULAR CONDUCTION DISORDERS IN THE FAMILY FROM KRASNOYARSK

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    A. A. Chernova

    2011-01-01

    Full Text Available Pedigree of the family from Krasnoyarsk city with hereditary disorders of intracardiac conduction was studied. The diagnosis of each family member was verified by electrocardiography (ECG, echocardiography , bicycle ergometry , ECG Holter monitoring. The family 10-year follow-up showed familial aggregation of intracardiac conduction disorders in grandson, niece, son of the proband niece, ie, in the III-degree relatives. Family history of III-degree relatives with intracardiac conduction disorders and discordant pathology is identified.

  3. Differential clinical characteristics and prognosis of intraventricular conduction defects in patients with chronic heart failure

    OpenAIRE

    Cinca, Juan; Mendez, Ana; Puig, Teresa; Ferrero, Andreu; Roig, Eulalia; Vazquez, Rafael; Gonzalez-Juanatey, Jose R.; Alonso-Pulpon, Luis; Delgado, Juan; Brugada, Josep; Pascual-Figal, Domingo; Brugada, J.; Batlle, M.; Berruezo, A.; Hevia, S.

    2013-01-01

    Aims Intraventricular conduction defects (IVCDs) can impair prognosis of heart failure (HF), but their specific impact is not well established. This study aimed to analyse the clinical profile and outcomes of HF patients with LBBB, right bundle branch block (RBBB), left anterior fascicular block (LAFB), and no IVCDs. Methods and results Clinical variables and outcomes after a median follow-up of 21 months were analysed in 1762 patients with chronic HF and LBBB (n = 532), RBBB (n = 134), LAFB ...

  4. Intraventricular hemorrhage of the newborn

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007301.htm Intraventricular hemorrhage of the newborn To use the sharing features on this page, please enable JavaScript. Intraventricular hemorrhage (IVH) of the newborn is bleeding into the ...

  5. Hemorragia intraventricular primaria

    OpenAIRE

    Pérez Nellar, Jesús; Roselló Silva, Héctor; Scherle Matamoros, Claudio; Hierro García, Daniel; Cutiño Maas, Yaineli; González González, Justo

    2006-01-01

    Se presentó el caso de una mujer de 21 años con hemorragia intraventricular primaria, causada por una malformación arterio-venosa. Se realizó estudio angiográfico cerebral y se diagnósticó una malformación vascular. Se embolizó la lesión y la paciente se recuperó sin secuelas neurológicas The case of a woman aged 21 with primary intraventricular haemorrhage caused by an arteriovenous malformation is presented. A cerebral angiographic study was carried out and a vascular malformation was di...

  6. Axonal Conduction Delays, Brain State, and Corticogeniculate Communication.

    Science.gov (United States)

    Stoelzel, Carl R; Bereshpolova, Yulia; Alonso, Jose-Manuel; Swadlow, Harvey A

    2017-06-28

    Thalamocortical conduction times are short, but layer 6 corticothalamic axons display an enormous range of conduction times, some exceeding 40-50 ms. Here, we investigate (1) how axonal conduction times of corticogeniculate (CG) neurons are related to the visual information conveyed to the thalamus, and (2) how alert versus nonalert awake brain states affect visual processing across the spectrum of CG conduction times. In awake female Dutch-Belted rabbits, we found 58% of CG neurons to be visually responsive, and 42% to be unresponsive. All responsive CG neurons had simple, orientation-selective receptive fields, and generated sustained responses to stationary stimuli. CG axonal conduction times were strongly related to modulated firing rates (F1 values) generated by drifting grating stimuli, and their associated interspike interval distributions, suggesting a continuum of visual responsiveness spanning the spectrum of axonal conduction times. CG conduction times were also significantly related to visual response latency, contrast sensitivity (C-50 values), directional selectivity, and optimal stimulus velocity. Increasing alertness did not cause visually unresponsive CG neurons to become responsive and did not change the response linearity (F1/F0 ratios) of visually responsive CG neurons. However, for visually responsive CG neurons, increased alertness nearly doubled the modulated response amplitude to optimal visual stimulation (F1 values), significantly shortened response latency, and dramatically increased response reliability. These effects of alertness were uniform across the broad spectrum of CG axonal conduction times. SIGNIFICANCE STATEMENT Corticothalamic neurons of layer 6 send a dense feedback projection to thalamic nuclei that provide input to sensory neocortex. While sensory information reaches the cortex after brief thalamocortical axonal delays, corticothalamic axons can exhibit conduction delays of <2 ms to 40-50 ms. Here, in the corticogeniculate

  7. Evolução clínica a longo prazo, correlacionando a presença de bloqueios da condução intraventricular em pacientes chagásicos e não chagásicos assintomáticos Long-term follow up of asymptomatic chagasic individuals with intraventricular conduction disturbances, correlating with non-chagasic patients

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    João Pimenta

    1999-12-01

    Full Text Available Estudo prospectivo para avaliar o potencial evolutivo, a longo prazo, dos transtornos da condução intraventricular em indivíduos chagásicos e não chagásicos assintomáticos. Foram submetidos a estudo eletrofisiológico, por metodologia convencional, 84 indivíduos portadores de bloqueio de ramo direito ou esquerdo, 55 chagásicos e 29 não chagásicos. A idade média foi de 45 anos nos chagásicos e 63 nos não chagásicos (pThis prospective study was designed to evaluate intraventricular conduction disturbances in asymptomatic patients with Chagas' disease, and patients with primary sclerosis of the conducting system of the heart (Lev-Lenègre's disease. Eighty-four asymptomatic individuals with right- or left-bundle branch block were submitted to electrophysiological evaluation and long-term follow-up. Fifty-five had positive serologic blood tests for Chagas' disease and 29 had Lev-Lenègre's disease. Mean-age of 45 years in chagasic and 63 in non-chagasic patients (p< 0.001. There were 54 (98.2% with right-bundle branch block in chagasic and 14 (48.3% among non-chagasic patients (p <0.001. Sinus nodal and atrioventricular nodal functions presented no differences in either group. However, mean HV interval was greater in the NCH than in the CH group (p< 0.01. After a mean follow-up of 121 ± 63.75 months among chagasic and 94.97 ± 67.55 months among non-chagasic patients, total mortality was 20 (36.6% patients in chagasic and 9 (31% among non-chagasic patients (NS. Cardiac death was recorded in 17 (85% individuals among chagasic and 3 (33.3% among non-chagasic patients(p <0.05. Sudden death occurred in 10 (50% among chagasic and was not observed in non-chagasic patients (p <0.01. In conclusion: 1. Asymptomatic chagasic individuals with intraventricular conduction disturbances showed higher cardiac mortality, sudden or non-sudden death in relation to non-chagasic individuals. 2. The evaluated electrophysiological parameters were of no

  8. Computed tomography of intraventricular hemorrhage

    International Nuclear Information System (INIS)

    Cho, Bum Shin; Shin, Kyoung Hee; Hahm, Chang Kok

    1982-01-01

    Computed tomography (CT) is a new non-invasive diagnostic imaging method, which has ability to differentiate C.S.F., hematoma, and even edematous brain from normal brain tissue. Prior to the introduction of the CT, the diagnosis of the intraventricular hemorrhage in living patients was difficult and was confirmed by surgery of autopsy. Intracranial hemorrhages are visible on the CT with density higher than brain tissue in acute phase. CT is an accurate method for detecting of intraventricular hemorrhage including detection of nature, location, amount, and associated changes. CT is also useful as a guidance and in the evaluation of fate of the hematomas by easily performable follow up studies. The causes of the intraventricular hemorrhages are hypertension, rupture of aneurysm, arteriovenous malformation, head trauma, brain tumor, and others. This study included evaluation of CT of 69 patients who show the high density in cerebral ventricular system during the period of 31 months from Feb. 1979 to Aug. 1981 in the Department of Radiology, College of Medicine, Hanyang University. The results were as follows. 1. Age distribution of the total 69 patient was broad ranging from 1 month to 80 years. 28% of patients were in the 6th decade. The mate to female ratio was 2 : 1. 2. The consciousness of patients at CT study: Those were conscious in 11 cases, stuporous in 41 cases and unconscious in 17 cases. 3. The causes of intraventricular hemorrhages were hypertension in 28 cases, head trauma in 12 cases, aneurysm in 4 cases, tumor in 2 cases and others in 23 cases. 4. 9 cases showed intraventricular hematomas only, other 60 cases showed associated intracranial hematomas: Those were intracerebral hematomas in 53 cases including 30 cases of basal ganglial and thalamic hematomas, subarachnoid hemorrhage in 17 cases, epidural hematomas in 3 cases, and subdural hematomas in 2 cases. 5. All cases of the intraventricular hematomas except one sowed hematoma in the lateral

  9. Effect of Phase Response Curve Skew on Synchronization with and without Conduction Delays

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    Carmen eCanavier

    2013-12-01

    Full Text Available A central problem in cortical processing including sensory binding and attentional gating is how neurons can synchronize their responses with zero or near-zero time lag. For a spontaneously firing neuron, an input from another neuron can delay or advance the next spike by different amounts depending upon the timing of the input relative to the previous spike. This information constitutes the phase response curve (PRC. We present a simple graphical method for determining the effect of PRC shape on synchronization tendencies and illustrate it using type 1 PRCs, which consist entirely of advances (delays in response to excitation (inhibition. We obtained the following generic solutions for type 1 PRCs, which include the pulse coupled leaky integrate and fire model. For pairs with mutual excitation, exact synchrony can be stable for strong coupling because of the stabilizing effect of the causal limit region of the PRC in which an input triggers a spike immediately upon arrival. However, synchrony is unstable for short delays, because delayed inputs arrive during a refractory period and cannot trigger an immediate spike. Right skew destabilizes antiphase and enables modes with time lags that grow as the conduction delay is increased. Therefore, right skew favors near-synchrony at short conduction delays and a gradual transition between synchrony and antiphase for pairs coupled by mutual excitation. For pairs with mutual inhibition, zero time lag synchrony is stable for conduction delays ranging from zero to a substantial fraction of the period for pairs. However, for right skew there is a preferred antiphase mode at short delays. In contrast to mutual excitation, left skew destabilizes antiphase for mutual inhibition so that synchrony dominates at short delays as well. These pairwise synchronization tendencies constrain the synchronization properties of neurons embedded in larger networks.

  10. Augmented reality in intraventricular neuroendoscopy.

    Science.gov (United States)

    Finger, T; Schaumann, A; Schulz, M; Thomale, Ulrich-W

    2017-06-01

    Individual planning of the entry point and the use of navigation has become more relevant in intraventricular neuroendoscopy. Navigated neuroendoscopic solutions are continuously improving. We describe experimentally measured accuracy and our first experience with augmented reality-enhanced navigated neuroendoscopy for intraventricular pathologies. Augmented reality-enhanced navigated endoscopy was tested for accuracy in an experimental setting. Therefore, a 3D-printed head model with a right parietal lesion was scanned with a thin-sliced computer tomography. Segmentation of the tumor lesion was performed using Scopis NovaPlan navigation software. An optical reference matrix is used to register the neuroendoscope's geometry and its field of view. The pre-planned ROI and trajectory are superimposed in the endoscopic image. The accuracy of the superimposed contour fitting on endoscopically visualized lesion was acquired by measuring the deviation of both midpoints to one another. The technique was subsequently used in 29 cases with CSF circulation pathologies. Navigation planning included defining the entry points, regions of interests and trajectories, superimposed as augmented reality on the endoscopic video screen during intervention. Patients were evaluated for postoperative imaging, reoperations, and possible complications. The experimental setup revealed a deviation of the ROI's midpoint from the real target by 1.2 ± 0.4 mm. The clinical study included 18 cyst fenestrations, ten biopsies, seven endoscopic third ventriculostomies, six stent placements, and two shunt implantations, being eventually combined in some patients. In cases of cyst fenestrations postoperatively, the cyst volume was significantly reduced in all patients by mean of 47%. In biopsies, the diagnostic yield was 100%. Reoperations during a follow-up period of 11.4 ± 10.2 months were necessary in two cases. Complications included one postoperative hygroma and one insufficient

  11. Conduction Delay Learning Model for Unsupervised and Supervised Classification of Spatio-Temporal Spike Patterns.

    Science.gov (United States)

    Matsubara, Takashi

    2017-01-01

    Precise spike timing is considered to play a fundamental role in communications and signal processing in biological neural networks. Understanding the mechanism of spike timing adjustment would deepen our understanding of biological systems and enable advanced engineering applications such as efficient computational architectures. However, the biological mechanisms that adjust and maintain spike timing remain unclear. Existing algorithms adopt a supervised approach, which adjusts the axonal conduction delay and synaptic efficacy until the spike timings approximate the desired timings. This study proposes a spike timing-dependent learning model that adjusts the axonal conduction delay and synaptic efficacy in both unsupervised and supervised manners. The proposed learning algorithm approximates the Expectation-Maximization algorithm, and classifies the input data encoded into spatio-temporal spike patterns. Even in the supervised classification, the algorithm requires no external spikes indicating the desired spike timings unlike existing algorithms. Furthermore, because the algorithm is consistent with biological models and hypotheses found in existing biological studies, it could capture the mechanism underlying biological delay learning.

  12. A case of traumatic intraventricular hemorrhage

    International Nuclear Information System (INIS)

    Ikeda, Yukio; Yamakawa, Kazuomi; Nakazawa, Shozo.

    1980-01-01

    CT scan is recognized to be a rapid, noninvasive and informative examination in evaluation of the head injured patient. It is also possible to evaluate the presence of the intracerebral hematoma without remarkable mass effect, cerebral contusion, associated cerebral edema and ventricular hemorrhage. We present a case of traumatic intraventricular hemorrhage. The patient was a 40-year-old male admitted to our hospital in a drowsy state following a fall from about one meter high. Craniogram showed a linear fracture in the left parietotemporal regions. In the CT scan, intraventricular hemorrhage associated with subarachnoid hemorrhage without intracerebral hematoma was shown. A symmetrical moderate dilatation of both lateral ventricles was also shown. Cerebral angiography revealed no abnormality. His condition deteriorated progressively, so ventricular drainage was performed, but he expired 5 days later. Considering this case, the mechanisms of pure intraventricular hemorrhage following head injury were discussed. (author)

  13. Evaluation of computed tomography of intraventricular hemorrhage

    International Nuclear Information System (INIS)

    Yoo, Seon Young; Lee, Young Sik; Suh, Jeong Soo; Rhee, Chung Sik; Kim, Hee Seup

    1983-01-01

    Prior to the introduction of computed tomography, the clinical and radiological diagnosis of the intraventricular hemorrhage in living patients was difficult. C.T. scanning is an invaluable investigation providing the rapid and noninvasive diagnosis of intracerebral and intraventricular hemorrhage. It reliably demonstrates the presence and distribution of fresh blood within the ventricular system. C.T. is also useful as a surgical guidance and in the evaluation of fate of the hematoma by easily performable follow-up studies. We reviewed 31 cases of intraventricular hemorrhage in C.T. in the department of radiology of Ewha Womans University Hospital during the period from August, 1982 to August, 1983. The results were as follows: 1. The most patients were encountered in the 5th decade and the male to female ratio was 1.2 : 1. 2. Hypertension was the main cause of the intraventricular hemorrhage; 18 out of 31 patients. Remaining 13 patients were caused by hypoxia, aneurysm, Moya Moya disease, coagulation defect, trauma and undetermined etiology. 3. 18 out of 31 patients showed hemorrhage in the lateral ventricles only and all ventricles in 10 patients. 4. 28 out of 31 patients showed associated with intracranial hematoma; Those were intracerebral hematomas in 16 patients, intracerebral hematoma with subarachnoid hemorrhage in 4 patients and extracerebral hematoma in 2 patients. 5. Outcome was assessed using the Glasgow scale. According to them, the total mortality rates was 54.8%, however, 32.3% of patients returned to normal or minor disability. Patients, who had hypertension and marked degree of hemorrhage in the ventricular systems had a poor outcome. Patients with only ventricular hemorrhage had better outcome than associated intracranial hematoma. 6. 16 out of 31 patients were treated by surgical methods and 15 out of 31 patients by conservative methods. 75% of patients were died in conservative treatment. 7. Conclusively, causes, degree of intraventricular

  14. Validation of double-spike electrograms as markers of conduction delay or block in atrial flutter.

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    Cosio, F G; Arribas, F; Barbero, J M; Kallmeyer, C; Goicolea, A

    1988-04-01

    Recent mapping studies of atrial flutter have shown that fragmented electrograms can be found in most cases from the posterior, posteroseptal and posterolateral walls of the right atrium. The fragmentation pattern most often consists of a double spike. To further assess double-spike electrograms as a possible marker of conduction delay, bipolar electrograms were continuously recorded during atrial overdrive pacing of common flutter from the right atrium (7 patients) and from the proximal coronary sinus (5). Baseline double-spike separation of 50 to 130 ms was unchanged in 1 patient and slightly increased (5 to 25 ms) in 4 by coronary sinus pacing. The electrogram sequence was unchanged and the surface morphology was similar to that of basal flutter. Right atrial pacing decreased double-spike separation by 25 to 85 ms from basal values of 45 to 175 ms (23 to 83%), suggesting fusion in the area of fragmented electrograms. These findings suggest that double-spike electrograms represent activation on both sides of a conduction delay zone. The changes induced in these electrograms by pacing from the anterior right atrium and the coronary sinus are consistent with flutter circuits rotating counterclockwise (frontal plane) in the posterior right atrial wall in common atrial flutter.

  15. The Prevalence of Intraventricular Haemorrhage and Associated ...

    African Journals Online (AJOL)

    The Prevalence of Intraventricular Haemorrhage and Associated Risk Factors in Preterm Neonates in the Neonatal Intensive Care Unit at the University Teaching ... any-IVH generated at the time of analysis was used in determining the prevalence of IVH and also as the dependent variable in multivariate logistic regression.

  16. Intraventricular antibiotics for bacterial meningitis in neonates.

    Science.gov (United States)

    Shah, Sachin S; Ohlsson, Arne; Shah, Vibhuti S

    2012-07-11

    Neonatal meningitis may be caused by bacteria, especially gram-negative bacteria, which are difficult to eradicate from the cerebrospinal fluid (CSF) using safe doses of antibiotics. In theory, intraventricular administration of antibiotics would produce higher antibiotic concentrations in the CSF than intravenous administration alone, and eliminate the bacteria more quickly. However, ventricular taps may cause harm. To assess the effectiveness and safety of intraventricular antibiotics (with or without intravenous antibiotics) in neonates with meningitis (with or without ventriculitis) as compared to treatment with intravenous antibiotics alone. The Cochrane Library, Issue 2, 2007; MEDLINE; EMBASE; CINAHL and Science Citation Index were searched in June 2007. The Oxford Database of Perinatal Trials was searched in June 2004. Pediatric Research (abstracts of proceedings) were searched (1990 to April 2007) as were reference lists of identified trials and personal files. No language restrictions were applied.This search was updated in May 2011. Selection criteria for study inclusion were: randomised or quasi-randomised controlled trials in which intraventricular antibiotics with or without intravenous antibiotics were compared with intravenous antibiotics alone in neonates (antibiotics compared to the group receiving intravenous antibiotics alone (RR 3.43; 95% CI 1.09 to 10.74; RD 0.30; 95% CI 0.08 to 0.53); NNTH 3; 95% CI 2 to 13). Duration of CSF culture positivity did not differ significantly (MD -1.20 days; 95% CI -2.67 to 0.27). In one trial that enrolled infants with gram-negative meningitis and ventriculitis, the use of intraventricular antibiotics in addition to intravenous antibiotics resulted in a three-fold increased RR for mortality compared to standard treatment with intravenous antibiotics alone. Based on this result, intraventricular antibiotics as tested in this trial should be avoided. Further trials comparing these interventions are not justified in

  17. Reliability Of A Novel Intracardiac Electrogram Method For AV And VV Delay Optimization And Comparability To Echocardiography Procedure For Determining Optimal Conduction Delays In CRT Patients

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    N Reinsch

    2009-03-01

    Full Text Available Background: Echocardiography is widely used to optimize CRT programming. A novel intracardiac electrogram method (IEGM was recently developed as an automated programmer-based method, designed to calculate optimal atrioventricular (AV and interventricular (VV delays and provide optimized delay values as an alternative to standard echocardiographic assessment.Objective: This study was aimed at determining the reliability of this new method. Furthermore the comparability of IEGM to existing echocardiographic parameters for determining optimal conduction delays was verified.Methods: Eleven patients (age 62.9± 8.7; 81% male; 73% ischemic, previously implanted with a cardiac resynchronisation therapy defibrillator (CRT-D underwent both echocardiographic and IEGM-based delay optimization.Results: Applying the IEGM method, concordance of three consecutively performed measurements was found in 3 (27% patients for AV delay and in 5 (45% patients for VV delay. Intra-individual variation between three measurements as assessed by the IEGM technique was up to 20 ms (AV: n=6; VV: n=4. E-wave, diastolic filling time and septal-to-lateral wall motion delay emerged as significantly different between the echo and IEGM optimization techniques (p < 0.05. The final AV delay setting was significantly different between both methods (echo: 126.4 ± 29.4 ms, IEGM: 183.6 ± 16.3 ms; p < 0.001; correlation: R = 0.573, p = 0.066. VV delay showed significant differences for optimized delays (echo: 46.4 ± 23.8 ms, IEGM: 10.9 ± 7.0 ms; p <0.01; correlation: R = -0.278, p = 0.407.Conclusion: The automated programmer-based IEGM-based method provides a simple and safe method to perform CRT optimization. However, the reliability of this method appears to be limited. Thus, it remains difficult for the examiner to determine the optimal hemodynamic settings. Additionally, as there was no correlation between the optimal AV- and VV-delays calculated by the IEGM method and the echo

  18. Intraventricular flow alterations due to dyssynchronous wall motion

    Science.gov (United States)

    Pope, Audrey M.; Lai, Hong Kuan; Samaee, Milad; Santhanakrishnan, Arvind

    2015-11-01

    Roughly 30% of patients with systolic heart failure suffer from left ventricular dyssynchrony (LVD), in which mechanical discoordination of the ventricle walls leads to poor hemodynamics and suboptimal cardiac function. There is currently no clear mechanistic understanding of how abnormalities in septal-lateral (SL) wall motion affects left ventricle (LV) function, which is needed to improve the treatment of LVD using cardiac resynchronization therapy. We use an experimental flow phantom with an LV physical model to study mechanistic effects of SL wall motion delay on LV function. To simulate mechanical LVD, two rigid shafts were coupled to two segments (apical and mid sections) along the septal wall of the LV model. Flow through the LV model was driven using a piston pump, and stepper motors coupled to the above shafts were used to locally perturb the septal wall segments relative to the pump motion. 2D PIV was used to examine the intraventricular flow through the LV physical model. Alterations to SL delay results in a reduction in the kinetic energy (KE) of the flow field compared to synchronous SL motion. The effect of varying SL motion delay from 0% (synchronous) to 100% (out-of-phase) on KE and viscous dissipation will be presented. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

  19. Teratoma with intraventricular free fat on CT

    International Nuclear Information System (INIS)

    Miura, Naohisa; Fuchinoe, Tokuro; Yahagi, Yasuji; Nakamura, Toshihiko

    1983-01-01

    Intracranial fat-containing congenital tumors are characterized by negative absorption values on computed tomography(CT). We are reporting a case of teratoma with intraventricular free fat diagnosed preoperatively by CT. The case is a 19-year-old female who was admitted to our hospital because of contineous severe headache, nausea and vomiting. At the time of admission, her physical and neurological examination was negative except for bilateral papilledema. CT demonstrated marked enlargement of the right lateral ventricle. In addition, there was negative absorption value (-90 H.U.), suggesting free fat, within right frontal horn layering above the CSF with a fluid level. Metrizamide ventriculography demonstrated complete obstruction and revealed an irregular shadow defect at the right foramen of Monro. At surgery, yellowish cheese-like material, white hair was found on the surface of the CSF. Tumor arose from the floor of the right foramen of Monro and extended upward. The patient made an uneventful recovery and was discharged 17 days after surgery. Intraventricular free fat is likely that to be released from the teratoma cyst ruptured spontaneously when the patient complained of severe headache 40 days prior to admission. There have been several published reports of the CT appearances of intracranial fat-containing tumors, however, teratoma with intraventricular free fat is very rare. It was concluded that fat-containing tumors should be highly suspected, when negative absorption values were found on CT. (author)

  20. Enhancement of delayed-rectifier potassium conductance by low concentrations of local anaesthetics in spinal sensory neurones

    Science.gov (United States)

    Olschewski, Andrea; Wolff, Matthias; Bräu, Michael E; Hempelmann, Gunter; Vogel, Werner; Safronov, Boris V

    2002-01-01

    Combining the patch-clamp recordings in slice preparation with the ‘entire soma isolation' method we studied action of several local anaesthetics on delayed-rectifier K+ currents in spinal dorsal horn neurones.Bupivacaine, lidocaine and mepivacaine at low concentrations (1–100 μM) enhanced delayed-rectifier K+ current in intact neurones within the spinal cord slice, while exhibiting a partial blocking effect at higher concentrations (>100 μM). In isolated somata 0.1–10 μM bupivacaine enhanced delayed-rectifier K+ current by shifting its steady-state activation characteristic and the voltage-dependence of the activation time constant to more negative potentials by 10–20 mV.Detailed analysis has revealed that bupivacaine also increased the maximum delayed-rectifier K+ conductance by changing the open probability, rather than the unitary conductance, of the channel.It is concluded that local anaesthetics show a dual effect on delayed-rectifier K+ currents by potentiating them at low concentrations and partially suppressing at high concentrations. The phenomenon observed demonstrated the complex action of local anaesthetics during spinal and epidural anaesthesia, which is not restricted to a suppression of Na+ conductance only. PMID:12055132

  1. Intraventricular Hemorrhage in Moderate to Severe Congenital Heart Disease.

    Science.gov (United States)

    Ortinau, Cynthia M; Anadkat, Jagruti S; Smyser, Christopher D; Eghtesady, Pirooz

    2018-01-01

    Determine the prevalence of intraventricular hemorrhage in infants with moderate to severe congenital heart disease, investigate the impact of gestational age, cardiac diagnosis, and cardiac intervention on intraventricular hemorrhage, and compare intraventricular hemorrhage rates in preterm infants with and without congenital heart disease. A single-center retrospective review. A tertiary care children's hospital. All infants admitted to St. Louis Children's Hospital from 2007 to 2012 with moderate to severe congenital heart disease requiring cardiac intervention in the first 90 days of life and all preterm infants without congenital heart disease or congenital anomalies/known genetic diagnoses admitted during the same time period. None. Cranial ultrasound data were reviewed for presence/severity of intraventricular hemorrhage. Head CT and brain MRI data were also reviewed in the congenital heart disease infants. Univariate analyses were undertaken to determine associations with intraventricular hemorrhage, and a final multivariate logistic regression model was performed. There were 339 infants with congenital heart disease who met inclusion criteria and 25.4% were born preterm. Intraventricular hemorrhage was identified on cranial ultrasound in 13.3% of infants, with the majority of intraventricular hemorrhage being low-grade (grade I/II). The incidence increased as gestational age decreased such that intraventricular hemorrhage was present in 8.7% of term infants, 19.2% of late preterm infants, 26.3% of moderately preterm infants, and 53.3% of very preterm infants. There was no difference in intraventricular hemorrhage rates between cardiac diagnoses. Additionally, the rate of intraventricular hemorrhage did not increase after cardiac intervention, with only three infants demonstrating new/worsening high-grade (grade III/IV) intraventricular hemorrhage after surgery. In a multivariate model, only gestational age at birth and African-American race were predictors

  2. Genes and environment in neonatal intraventricular hemorrhage.

    Science.gov (United States)

    Ment, Laura R; Ådén, Ulrika; Bauer, Charles R; Bada, Henrietta S; Carlo, Waldemar A; Kaiser, Jeffrey R; Lin, Aiping; Cotten, Charles Michael; Murray, Jeffrey; Page, Grier; Hallman, Mikko; Lifton, Richard P; Zhang, Heping

    2015-12-01

    Emerging data suggest intraventricular hemorrhage (IVH) of the preterm neonate is a complex disorder with contributions from both the environment and the genome. Environmental analyses suggest factors mediating both cerebral blood flow and angiogenesis contribute to IVH, while candidate gene studies report variants in angiogenesis, inflammation, and vascular pathways. Gene-by-environment interactions demonstrate the interaction between the environment and the genome, and a non-replicated genome-wide association study suggests that both environmental and genetic factors contribute to the risk for severe IVH in very low-birth weight preterm neonates. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Evaluation of Intraventricular Hemorrhage in Pediatric Intracerebral hemorrhage

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    Kleinman, Jonathan T; Beslow, Lauren A; Engelmann, Kyle; Smith, Sabrina E; Licht, Daniel J; Ichord, Rebecca N; Jordan, Lori C

    2012-01-01

    Previous studies of pediatric intracerebral hemorrhage have investigated isolated intraparenchymal hemorrhage. We investigated whether detailed assessment of intraventricular hemorrhage enhanced outcome prediction after intracerebral hemorrhage. We prospectively enrolled 46 children, full-term to 17 years, median age 2.7 years with spontaneous intraparenchymal hemorrhage and/or intraventricular hemorrhage. Outcome was assessed with the King’s Outcome Scale for Childhood Head Injury. Twenty-six (57%) had intraparenchymal hemorrhage, 10 (22%) had pure intraventricular hemorrhage, and 10 (22%) had both. There were 2 deaths, both with intraparenchymal hemorrhage + intraventricular hemorrhage volume ≥4% of total brain volume. Presence of intraventricular hemorrhage was not associated with poor outcome, but hydrocephalus showed a trend (p=0.09) toward poor outcome. In receiver operating characteristic curve analysis, combined intraparenchymal hemorrhage + intraventricular hemorrhage volume also showed a trend toward better outcome prediction than intraparenchymal hemorrhage volume alone. Although not an independent outcome predictor, future studies should assess intraventricular hemorrhage qualitatively and quantitatively. PMID:22068828

  4. Intraventricular hemorrhage in preterm infants: coagulation perspectives.

    Science.gov (United States)

    Kuperman, Amir A; Kenet, Gili; Papadakis, Emmanuel; Brenner, Benjamin

    2011-10-01

    It has long been considered that a severe coagulation deficiency in premature newborns could be a major contributing factor in the occurrence of intraventricular hemorrhage (IVH). High-grade IVH has also been shown to coincide with severe derangement of coagulation in extremely low birth weight infants. This review focuses on the relevance of the physiologically developing immature hemostatic system to IVH, and the potential benefit of agents affecting hemostasis for IVH therapy or prevention in preterm infants. The findings of small, open-label interventional studies on the effect of ethamsylate, vitamin K, fresh frozen plasma, recombinant activated factor VII, and prothrombin complex concentrate on the premature coagulation system will be reviewed. © Thieme Medical Publishers.

  5. Intraventricular hydatid cyst in a child

    Directory of Open Access Journals (Sweden)

    Kamath Sulata

    2009-10-01

    Full Text Available Hydatid disease is caused by the infestation of the larvae of tapeworms of the genus Echinococcus. The definitive hosts of Echinococcus are various carnivores, the common being the dog. All mammals (more often sheep and cattle are intermediate hosts. Humans get infected through the feco-oral route by ingestion of food or milk contaminated by dog feces containing ova of the parasite or by direct contact with dogs. The most common sites of infestation are the liver (75% and lungs (15%. Various authors state a frequency of hydatidosis of the brain ranging between only 0.2-4% of cases. [1],[2],[3] The prognosis following surgical intervention is good, especially in pediatric age. [2],[3] Hence early diagnosis of this condition is crucial. We report a rare case of a child with a large intraventricular hydatid cyst that had an excellent recovery following surgery.

  6. Computed tomographic investigations on intraventricular hematomas

    International Nuclear Information System (INIS)

    Laber-Szillat, S.

    1982-01-01

    This work investigated in 106 patients with intraventricular hematomas all the known factors which can have an influence on prognosis: age, sex, anamnesis of the patients, size, extent and localization of the intracranial bleeding, underlying angiopathy and differences between arterial and venous and spontaneous and traumatic bleedings. It was shown that the state of mind was the deciding prognostic factor, whereby viligance was the cumulative expression of all other investigated influences. A computed tomography (CT) examination is deciding in the question of operative hydrocephalus care. In 13 patients it was further shown, how clearly CT results and brain dissection allowed themselves to be compared. The computed tomographic examination method is best suited to achieve even physiological and more extensive prognostic possibilities. (orig.) [de

  7. Criteria for intraventricular conduction disturbances and pre-excitation

    NARCIS (Netherlands)

    Willems, J.L.; Robles de Medina, E.O.; Bernard, R.; Coumel, Ph.; Fisch, Ch.; Mazur, N.A.; Meijler, F.L.; Mogensen, L.; Moret, P.; Pisa, Z.; Rautaharju, P.M.; Surawicz, B.; Watanabe, Y.; Wellens, H.J.J.; WHO/ISFC Task Force ad hoc

    1985-01-01

    In an effort to standardize terminology and criteria for clinical electrocardiography, and as a follow-up of its work on definitions of terms related to cardiac rhythm, an Ad Hoc Working Group established by the World Health Organization and the International Society and Federation of Cardiology

  8. CLINICAL AND MORPHOLOGICAL CLASSIFICATION OF CEREBRAL INTRAVENTRICULAR HEMORRHAGES

    Directory of Open Access Journals (Sweden)

    V. V. Vlasyuk

    2013-01-01

    Full Text Available Inconsistency of the current classification of cerebral intraventricular hemorrhages is discussed in the article. The author explains divergence of including of the subependymal (1st stage and intracerebral (4th stage hemorrhages into this classification. A new classification of cerebral intraventricular hemorrhages including their origin, phases and stages is offered. The most common origin of intraventricular hemorrhages is subependymal hemorrhage (82,2%. Two phases of hemorrhage were distinguished: bleeding phase and resorption phase. Stages of intraventricular hemorrhages reflecting the blood movement after the onset of bleeding are the following: 1 — infill of the up to ½ of the lateral ventricles without their enlargement; 2 — infill of more than ½ of the lateral ventricles with their enlargement; 3 — infill of the IV ventricle, of the cerebellomedullary cistern and its dislocation into the subarachnoid space of the cerebellum, pons varolii, medulla oblongata and spinal cord.

  9. Ventricular Zone Disruption in Human Neonates With Intraventricular Hemorrhage

    NARCIS (Netherlands)

    McAllister, James P.; Guerra, Maria Montserrat; Ruiz, Leandro Castaneyra; Jimenez, Antonio J.; Dominguez-Pinos, Dolores; Sival, Deborah; den Dunnen, Wilfred; Morales, Diego M.; Schmidt, Robert E.; Rodriguez, Esteban M.; Limbrick, David D.

    2017-01-01

    To determine if ventricular zone (VZ) and subventricular zone (SVZ) alterations are associated with intraventricular hemorrhage (IVH) and posthemorrhagic hydrocephalus, we compared postmortem frontal and subcortical brain samples from 12 infants with IVH and 3 nonneurological disease controls

  10. Experimental hydrocephalus following mechanical increment of intraventricular pulse pressure.

    Science.gov (United States)

    Di Rocco, C; Pettorossi, V E; Caldarelli, M; Mancinelli, R; Velardi, F

    1977-11-15

    Experimental hydrocephalus has been induced in lambs by artificial increase of the amplitude of intraventricular cerebrospinal fluid (CSF) oscillations related to arterial pulsations, without concomitant changes of the mean CSF-pressure. The characteristics of this hydrocephalus demonstrate that the intraventricular CSF-pulsations can play a role in the genesis of ventricular dilation. Such a method may be used to produce an original model of hydrocephalus independent of changes of CSF-circulation or absorption.

  11. Evaluation of Intraventricular Hemorrhage in Pediatric Intracerebral hemorrhage

    OpenAIRE

    Kleinman, Jonathan T; Beslow, Lauren A; Engelmann, Kyle; Smith, Sabrina E; Licht, Daniel J; Ichord, Rebecca N; Jordan, Lori C

    2011-01-01

    Previous studies of pediatric intracerebral hemorrhage have investigated isolated intraparenchymal hemorrhage. We investigated whether detailed assessment of intraventricular hemorrhage enhanced outcome prediction after intracerebral hemorrhage. We prospectively enrolled 46 children, full-term to 17 years, median age 2.7 years with spontaneous intraparenchymal hemorrhage and/or intraventricular hemorrhage. Outcome was assessed with the King’s Outcome Scale for Childhood Head Injury. Twenty-si...

  12. Prevalence of conduction delay of the right atrium in patients with SSS: implications for pacing site selection.

    Science.gov (United States)

    Verlato, Roberto; Zanon, Francesco; Bertaglia, Emanuele; Turrini, Pietro; Baccillieri, Maria Stella; Baracca, Enrico; Bongiorni, Maria Grazia; Zampiero, Aldo; Zonzin, Pietro; Pascotto, Pietro; Venturini, Diego; Corbucci, Giorgio

    2007-09-01

    To evaluate the prevalence of severe right atrial conduction delay in patients with sinus node dysfunction (SND) and atrial fibrillation (AF) and the effects of pacing in the right atrial appendage (RAA) and in the inter-atrial septum (IAS). Forty-two patients (15 male, 72 +/- 7 years) underwent electrophysiologic study to measure the difference between the conduction time from RAA to coronary sinus ostium during stimulation at 600 ms and after extrastimulus (DeltaCTos). Patients were classified as group A if DeltaCTos > 60 ms and group B if IAS pacing and algorithms ON/OFF. Fifteen patients (36%, group A) had DeltaCTos = 76 +/- 11 ms and 27 patients (64%, group B) had DeltaCTos = 36 +/- 20 ms. Twenty-two patients were paced at the RAA and 20 at the IAS. During the study, no AF recurrences were reported in 11 of 42 (26%) patients, independently of RAA or IAS pacing. Patients from group A and RAA pacing had 0.79 +/- 0.81 episodes of AF/day during DDD, which increased to 1.52 +/- 1.41 episodes of AF/day during DDDR + Alg (P = 0.046). Those with IAS pacing had 0.5 +/- 0.24 episodes of AF/day during DDD, which decreased to 0.06 +/- 0.08 episodes of AF/day during DDDR + Alg (P = 0.06). In group B, no differences were reported between pacing sites and pacing modes. Severe right atrial conduction delay is present in one-third of patients with SND and AF: continuous pacing at the IAS is superior to RAA for AF recurrences. In patients without severe conduction delay, no differences between pacing site or mode were observed.

  13. Patient-Specific Modeling of Intraventricular Hemodynamics

    Science.gov (United States)

    Vedula, Vijay; Marsden, Alison

    2017-11-01

    Heart disease is the one of the leading causes of death in the world. Apart from malfunctions in electrophysiology and myocardial mechanics, abnormal hemodynamics is a major factor attributed to heart disease across all ages. Computer simulations offer an efficient means to accurately reproduce in vivo flow conditions and also make predictions of post-operative outcomes and disease progression. We present an experimentally validated computational framework for performing patient-specific modeling of intraventricular hemodynamics. Our modeling framework employs the SimVascular open source software to build an anatomic model and employs robust image registration methods to extract ventricular motion from the image data. We then employ a stabilized finite element solver to simulate blood flow in the ventricles, solving the Navier-Stokes equations in arbitrary Lagrangian-Eulerian (ALE) coordinates by prescribing the wall motion extracted during registration. We model the fluid-structure interaction effects of the cardiac valves using an immersed boundary method and discuss the potential application of this methodology in single ventricle physiology and trans-catheter aortic valve replacement (TAVR). This research is supported in part by the Stanford Child Health Research Institute and the Stanford NIH-NCATS-CTSA through Grant UL1 TR001085 and partly through NIH NHLBI R01 Grant 5R01HL129727-02.

  14. Intraventricular trigonal meningioma: Neuronavigation? No, thanks!

    Science.gov (United States)

    Silva, Danilo O A; Matis, Georgios K; Costa, Leonardo F; Kitamura, Matheus A P; Birbilis, Theodossios A; Azevedo Filho, Hildo R C

    2011-01-01

    Most of the time meningiomas are benign brain tumors and surgical removal ensures cure in the vast majority of the cases. Thus, whenever possible, complete surgical resection should be the goal of the treatment. This is a report of our surgical technique for the operative resection of a trigonal meningioma in a resource-limited setting. The necessity of accurate and deep knowledge of the regional anatomy is outlined. A 44-year-old male presented to our outpatient clinic complaining of cephalalgia increasing in frequency and intensity over the last month. His neurological exam was normal, yet a brain computed tomography scan revealed a lesion in the right trigone of the ventricular system. The diagnosis of possible meningioma was set. After thoroughly informing the patient, tumor resection was decided. An intraparietal sulcus approach was favored without the use of any modern technological aids such as intraoperative magnetic resonance imaging or neuronavigation. The postoperative course was uneventful and a postoperative computed tomography scan demonstrated the complete resection of the tumor. The patient was discharged two days later with no neurological deficits. In a two-year-follow-up he remains recurrence-free. In the current cost-effective era it is still possible to safely remove an intraventricular trigonal meningioma without the convenience of neuronavigation. Since the best neuronavigator is the profound neuroanatomical knowledge, no technological advancement could replace a well-educated and trained neurosurgeon.

  15. Intraventricular hemorrhage in preterm infants and coagulation--ambivalent perspectives?

    Science.gov (United States)

    Kuperman, Amir A; Brenner, Benjamin; Kenet, Gili

    2013-01-01

    Intraventricular hemorrhage (IVH) is a major complication of preterm birth, and large hemorrhages may yield significant future disability. During the last few decades, the survival of preterm infants has increased dramatically. Nevertheless, morbidity is still a major problem especially for very young and extremely low birth weight infants. As both, mortality and incidence of morbidities known to influence outcome, show a weekly decline with increasing gestational age, prematurity and low birth weight have been identified as major risk factors for IVH occurrence. This stems probably from the increased vulnerability of the premature germinal matrix as well as the physiologically impaired hemostasis, demonstrated in neonates. The hypothesis that a severe coagulation deficiency in the premature newborn could be a major contributing factor for IVH has been suggested, and small open label interventional studies targeting the premature coagulation system have been conducted with ethamsylate, vitamin K, fresh frozen plasma, recombinant activated factor VII and prothrombin complex concentrate. Nevertheless, potential venous origin of hemorrhages, which may be related to thrombophilic risk factors, has also been discussed. The following manuscript will focus upon IVH pathogenesis and address potential therapies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Path integration of head direction: updating a packet of neural activity at the correct speed using axonal conduction delays.

    Science.gov (United States)

    Walters, Daniel; Stringer, Simon; Rolls, Edmund

    2013-01-01

    The head direction cell system is capable of accurately updating its current representation of head direction in the absence of visual input. This is known as the path integration of head direction. An important question is how the head direction cell system learns to perform accurate path integration of head direction. In this paper we propose a model of velocity path integration of head direction in which the natural time delay of axonal transmission between a linked continuous attractor network and competitive network acts as a timing mechanism to facilitate the correct speed of path integration. The model effectively learns a "look-up" table for the correct speed of path integration. In simulation, we show that the model is able to successfully learn two different speeds of path integration across two different axonal conduction delays, and without the need to alter any other model parameters. An implication of this model is that, by learning look-up tables for each speed of path integration, the model should exhibit a degree of robustness to damage. In simulations, we show that the speed of path integration is not significantly affected by degrading the network through removing a proportion of the cells that signal rotational velocity.

  17. ''Intraventricular'' hemorrhage and cystic periventricular leukomalacia in preterm infants: how are they related?

    NARCIS (Netherlands)

    Kusters, C.D.J.; Chen, M.L.; Follett, P.L.; Dammann, O.

    2009-01-01

    Intraventricular hemorrhage and cystic periventricular leukomalacia are often co-occurring characteristics of brain damage in preterm infants. Using data from 1016 infants born before 30 completed weeks' gestational age, we sought to clarify the relationship between severe intraventricular

  18. The delayed rectifier potassium conductance in the sarcolemma and the transverse tubular system membranes of mammalian skeletal muscle fibers

    Science.gov (United States)

    DiFranco, Marino; Quinonez, Marbella

    2012-01-01

    A two-microelectrode voltage clamp and optical measurements of membrane potential changes at the transverse tubular system (TTS) were used to characterize delayed rectifier K currents (IKV) in murine muscle fibers stained with the potentiometric dye di-8-ANEPPS. In intact fibers, IKV displays the canonical hallmarks of KV channels: voltage-dependent delayed activation and decay in time. The voltage dependence of the peak conductance (gKV) was only accounted for by double Boltzmann fits, suggesting at least two channel contributions to IKV. Osmotically treated fibers showed significant disconnection of the TTS and displayed smaller IKV, but with similar voltage dependence and time decays to intact fibers. This suggests that inactivation may be responsible for most of the decay in IKV records. A two-channel model that faithfully simulates IKV records in osmotically treated fibers comprises a low threshold and steeply voltage-dependent channel (channel A), which contributes ∼31% of gKV, and a more abundant high threshold channel (channel B), with shallower voltage dependence. Significant expression of the IKV1.4 and IKV3.4 channels was demonstrated by immunoblotting. Rectangular depolarizing pulses elicited step-like di-8-ANEPPS transients in intact fibers rendered electrically passive. In contrast, activation of IKV resulted in time- and voltage-dependent attenuations in optical transients that coincided in time with the peaks of IKV records. Normalized peak attenuations showed the same voltage dependence as peak IKV plots. A radial cable model including channels A and B and K diffusion in the TTS was used to simulate IKV and average TTS voltage changes. Model predictions and experimental data were compared to determine what fraction of gKV in the TTS accounted simultaneously for the electrical and optical data. Best predictions suggest that KV channels are approximately equally distributed in the sarcolemma and TTS membranes; under these conditions, >70% of IKV

  19. Greater efficiency of water use in poplar clones having a delayed response of mesophyll conductance to drought.

    Science.gov (United States)

    Théroux Rancourt, Guillaume; Éthier, Gilbert; Pepin, Steeve

    2015-02-01

    Improvement of water use efficiency is a key objective to improve the sustainability of cultivated plants, especially fast growing species with high water consumption like poplar. It is well known that water use efficiency (WUE) varies considerably among poplar genotypes, and it was recently suggested that the use of the mesophyll-to-stomatal conductance ratio (gm/gs) would be an appropriate trait to improve WUE. The responses of 7-week-old cuttings of four hybrid poplar clones and one native Balsam poplar (Populus balsamifera L.) to a water stress-recovery cycle were examined to evaluate the relation between the gm/gs ratio and transpiration efficiency (TE), a leaf-level component of WUE. A contrasting gs response to water stress was observed among the five clones, from stomatal closure early on during soil drying up to limited closure in Balsam poplar. However in the hybrids, the decline in gm was consistently delayed by a few days compared with gs. Moreover, in the most water use-efficient hybrids, the recovery following rehydration occurred faster for gm than for gs. Thus, the delay in the response of gm to drought and its faster recovery upon rewatering increased the gm/gs of the hybrids and this ratio scaled positively with TE. Our results support the use of the gm/gs ratio to select genotypes with improved WUE, and the notion that breeding strategies focusing mainly on stomatal responses to soil drying should also look for a strong curvilinearity between net carbon assimilation rate and gs, the indication of a significant increase in gm/gs in the earlier stages of stomatal closure. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Magnetic resonance imaging (MRI) of an intraventricular hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Ryungchan; Higashi, Tooru; Ito, Shotaro; Kadoya, Satoru; Takarada, Akira; Sato, Shuji; Kurauchi, Manabu.

    1987-08-01

    The utility of MRI was investigated in 10 patients with intraventricular hemorrhage. MRI was found to be, in many respects, superior to CT: 1) MRI is able to detect to some extent the aging of an intraventricular hematoma. 2) It can determine the character of intraventricular cerebrospinal fluid, whether it is normal, bloody, or hyperprotein. 3) It can detect the cause of hemorrhage in the case of arterio-venous malformation. 4) MRI permits the detection of the penetration course and the location of a ventricular hematoma. 5) It can clearly detect periventricular lesions of early-stage hydrocephalus, accompanied by increased intracranial pressure and followed by intraventricular hemorrhage, by imaging the periventricular high-signal-intensity area. 6) MRI can clearly diagnose complications of intracranial lesions. For instance, it can distinguish subdural fluid collection from chronic subdural hematoma and can detect whether a cerebral infarction is new or old. On the other hand, MRI also has some disadvantages: 1) The imaging time is long, and clinical application is difficult, in serious and/or infant cases. 2) It is impossible to use MRI in some patients who have magnetic material in their bodies. 3) The spatial-image resolution is not good.

  1. Periventricular-intraventricular haemorrhage in low-birth-weight ...

    African Journals Online (AJOL)

    The prevalence of periventricular-intraventricular haemorrhage (PV-IVH) aInong very-low-birthweight infants at Baragwanath Hospital has not been well docwnented. In this prospective study, a total of 282 live-born infants with birth weights of 1 000 - 1 749 g were studied over a 41/2-month period. Every infant had at least ...

  2. Clinical aspects and prognosis of intraventricular hemorrhage with cerebrovascular disease

    International Nuclear Information System (INIS)

    Ikeda, Yukio; Nakazawa, Shozo; Higuchi, Hiroshi; Ueda, Kenji; Kouzo

    1982-01-01

    Intraventricular hemorrhage with cerebrovascular disease was identified in 81 cases and death occurred within seven days in 34 cases. Hypertension was the most common etiological factor, accounting for 40 of the 81 cases. Cerebral aneurysm was the second most common cause accounting for 27 cases, arteriovenous malformation accounted for 9 of the cases, and 5 were of other causes. Signs of primary or secondary brain stem dysfunction were mainly seen in cases with hypertension and aneurysm, while cases with arteriovenous malformation had benign courses. The mortality depended on the severity of intraventricular hemorrhage; i.e., the distribution, site, and the number of cast formation. The presence of intraventricular clot in the third and/or fourth ventricles was correlated with a high mortality rate, especially in cases accompanied by cast formation and third and fourth ventricular dilatation, which affects hypothalamus and brain stem function. Analysis of CT findings for the mechanism of intraventricular hemorrhage revealed three types: extension type, in which massive intracerebral hematomas extended and ruptured into ventricles; the direct type, which bled directly into ventricles without forming definite intracerebral hematomas; and the reflux type, which was characterized by reflux of the subarachnoid blood. (J.P.N.)

  3. Prenatal intraventricular hemorrhage in a term infant with congenital ...

    African Journals Online (AJOL)

    Intraventricular hemorrhage (IVH) occurs rarely in term infant, since subependymal area is a transient structure in fetal life. IVH in term infant indicates generally that it happened prenatally. Congenital cytomegalovirus (CMV) infection is frequent, occurring in 1% of live births. It is a severe infection leading to developmental ...

  4. Hemorragia intraventricular en el neonato prematuro Intraventricular hemorrage in preterm infants

    Directory of Open Access Journals (Sweden)

    José William Cornejo Ochoa

    2005-01-01

    Full Text Available La hemorragia intraventricular (HIV es la principal complicación neurológica en los prematuros; consiste en sangrado de la matriz germinal y las regiones periventriculares del cerebro. Su frecuencia y gravedad aumentan en la medida en que es menor el peso al nacimiento; se la halla entre 10 y 20% de los neonatos de 1.000-1.500 gramos y hasta en 70% en los menores de 700 gramos; se presenta en 85% de las veces en las primeras 72 horas posparto y en 95% ya es evidente al finalizar la primera semana; son múltiples los factores maternos y fetales que se han encontrado asociados con el aumento o disminución de su frecuencia, además del uso de algunos medicamentos. Se han propuesto diversos mecanismos fisiopatogénicos asociados a la inmadurez neurológica para explicar la aparición de la HIV. Las manifestaciones clínicas son variables en cuanto a presentación y evolución. La confirmación diagnóstica, la clasificación y el pronóstico se basan en la ecografía transfontanelar. La principal medida preventiva es la disminución de la frecuencia del parto prematuro; los resultados de otras medidas como el uso prenatal y posnatal de algunos medicamentos para evitarla y tratarla han sido variables. El pronóstico depende de la extensión de la hemorragia, del desarrollo de leucomalacia periventricular y del grado de dilatación ventricular. Neonatal intraventricular hemorrage (IVH is the main neurological complication in preterm infants involving bleeding into the germinal matrix and the periventricular brain areas. Its incidence and severity are greater with lower birthweigth: from 10-20% in 1.000-1.500 g babies to 70% in those less than 700 g. Most often (85% it appears during the first 72 hours after birth and almost 95% of the cases are evident by the end of the first week of life. Many maternal and fetal risk factors are associated with the risk of neonatal IVH. Diferent pathogenic mechanisms associated with an immature central nervous

  5. A randomized, placebo-controlled pilot study of patients with spontaneous intraventricular haemorrhage treated with intraventricular thrombolysis.

    Science.gov (United States)

    King, Nicolas K K; Lai, Jin Li; Tan, Li Bing; Lee, Kah Keow; Pang, Boon Chuan; Ng, Ivan; Wang, Ernest

    2012-07-01

    Intraventricular hemorrhage (IVH) occurring after spontaneous intracerebral hemorrhage (ICH) is an independent risk factor for mortality. The use of intraventricular urokinase (Uk) to reduce intraventricular blood clot volume and improve outcome was investigated. Patients with IVH requiring external ventricular drainage were recruited and randomized into a double-blind placebo controlled study. Assessments of collected cerebrospinal fluid (CSF) haemoglobin (Hb) and serial CT scans were performed. The study outcomes were: infection rates, length of stay in the intensive care unit, survival, National Institutes of Health Stroke Scale score; and modified Rankin Scale scores. Our results showed an increase in both the drained CSF Hb concentration in patients treated with Uk compared to placebo and in the rate of resolution clot volume. No differences were found in the other outcome measures but there was a trend towards lowered mortality in the group treated with Uk. Therefore, intraventricular Uk resulted in faster resolution of IVH with no adverse events. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Unusual presentation of hydatid cyst – ruptured intraventricular hydatid

    Directory of Open Access Journals (Sweden)

    Sneha H Thakur

    2017-01-01

    Full Text Available Echinococcosis in humans occurs as a result of infection by the larval stages of taenid cestodes of the genus Echinococcus. Most of the intracranial hydatids develop in brain parenchyma. Hydatid cyst within the cerebral ventricle is quite unusual. Literature review showed few case reports of childhood as well as adult intraventricular hydatid cysts. None of these cases presented for the first time with features of ruptured intraventricular cyst. This is a very rare presentation of a common disease. The possibility of infestation with E. granulosus should be included in the differential diagnosis of raised intracranial tension in patients reporting from endemic areas, because the prognosis following surgical intervention is excellent, especially in the pediatric age group.

  7. Recurrent Candida albicans Ventriculitis Treated with Intraventricular Liposomal Amphotericin B

    Directory of Open Access Journals (Sweden)

    Demet Toprak

    2015-01-01

    Full Text Available Central nervous system (CNS infection with Candida is rare but significant because of its high morbidity and mortality. When present, it is commonly seen among immunocompromised and hospitalized patients. Herein, we describe a case of a four-year-old boy with acute lymphoblastic leukemia (ALL who experienced recurrent Candida albicans meningitis. The patient was treated successfully with intravenous liposomal amphotericin B at first attack, but 25 days after discharge he was readmitted to hospital with symptoms of meningitis. Candida albicans was grown in CFS culture again and cranial magnetic resonance imaging (MRI showed ventriculitis. We administered liposomal amphotericin B both intravenously and intraventricularly and favorable result was achieved without any adverse effects. Intraventricular amphotericin B may be considered for the treatment of recurrent CNS Candida infections in addition to intravenous administration.

  8. Mechanisms of Hydrocephalus after Neonatal and Adult Intraventricular Hemorrhage

    OpenAIRE

    Strahle, Jennifer; Garton, Hugh J.L.; Maher, Cormac O.; Muraszko, Karin M.; Keep, Richard F.; Xi, Guohua

    2012-01-01

    Intraventricular hemorrhage (IVH) is a cause of significant morbidity and mortality and is an independent predictor of a worse outcome in intracerebral hemorrhage (ICH) and germinal matrix hemorrhage (GMH). IVH may result in both injuries to the brain as well as hydrocephalus. This paper reviews evidence on the mechanisms and potential treatments for IVH-induced hydrocephalus. One frequently cited theory to explain hydrocephalus after IVH involves obliteration of the arachnoid villi by microt...

  9. Teratoma with intraventricular free fat on CT. Case report

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Naohisa; Fuchinoe, Tokuro; Yahagi, Yasuji; Nakamura, Toshihiko [Toshima Municipal Hospital of Metropolitan Tokyo (Japan)

    1983-11-01

    Intracranial fat-containing congenital tumors are characterized by negative absorption values on computed tomography(CT). We are reporting a case of teratoma with intraventricular free fat diagnosed preoperatively by CT. The case is a 19-year-old female who was admitted to our hospital because of continuous severe headache, nausea and vomiting. At the time of admission, her physical and neurological examination was negative except for bilateral papilledema. CT demonstrated marked enlargement of the right lateral ventricle. In addition, there was negative absorption value (-90 H.U.), suggesting free fat, within right frontal horn layering above the CSF with a fluid level. Metrizamide ventriculography demonstrated complete obstruction and revealed an irregular shadow defect at the right foramen of Monro. At surgery, yellowish cheese-like material, white hair was found on the surface of the CSF. Tumor arose from the floor of the right foramen of Monro and extended upward. The patient made an uneventful recovery and was discharged 17 days after surgery. Intraventricular free fat is likely that to be released from the teratoma cyst ruptured spontaneously when the patient complained of severe headache 40 days prior to admission. There have been several published reports of the CT appearances of intracranial fat-containing tumors, however, teratoma with intraventricular free fat is very rare. It was concluded that fat-containing tumors should be highly suspected, when negative absorption values were found on CT.

  10. The intraventricular filling vortex under heightened aortic blood pressure

    Science.gov (United States)

    Nelsen, Nicholas; Gaddam, Manikantam; Santhanakrishnan, Arvind

    2017-11-01

    Hypertension, or high aortic blood pressure, can induce structural changes in the left ventricle (LV) such as concentric hypertrophy. Previous studies have identified that the intraventricular filling vortex serves as an effective means of blood transport during diastolic filling. However, a fundamental understanding of how hypertension affects this vortex is unavailable. This knowledge can be useful for improving diagnosis and treatment of related heart disease conditions, including hypertensive heart failure. In this experimental study, we hypothesized that the circulation of the filling vortex would diminish with increased aortic pressure. Using a LV physical model within a left heart simulator, we performed hemodynamic measurements to acquire pressure and volumetric inflow profiles and 2D particle image velocimetry to visualize the intraventricular flow fields. Peak aortic pressures of 120 mm Hg, 140 mm Hg, and 160 mm Hg were each tested at heart rates of 70, 100, and 110 beats per minute, under: 1) reduced ejection fraction (EF), and 2) constant EF. Our results indicate that peak vortex circulation is reduced under elevated aortic pressures. Hemodynamics and characteristics of the intraventricular filling vortex in all examined experimental cases will be presented.

  11. Successful neuroendoscopic treatment of intraventricular brain abscess rupture

    Directory of Open Access Journals (Sweden)

    Takafumi Nishizaki

    2011-07-01

    Full Text Available Intraventricular rupture of a brain abscess is still associated with a high mortality rate. Here, we report such a case in a patient with normal immunity that was treated successfully using neuroendoscopic approach. A 69-yearold man who had presented with headache and fever developed confusion and restlessness. Magnetic resonance imaging revealed a mass with ring enhancement extending to the right ventricle. Emergency aspiration of cerebrospinal fluid (CSF from the spinal canal revealed severe purulent meningitis. Bacterial culture of the CSF and blood was negative. Because of prolonged consciousness disturbance, the patient underwent evacuation of the intraventrcular abscess using a neuroendoscope. The pus was centrifuged and collected for bacterial culture, and this revealed Streptococcus intermedius/milleri. After implantation of a ventricular catheter, gentamicin sulfate was administered twice a day for 9 days. Cefotaxime sodium was also administered intravenously for 14 days, followed by oral administration of cefcapene pivoxil hydrochloride for 10 days. The patient made a complete recovery, and was discharged 31 days after admission. After 20 months of follow-up, he is doing well and has returned to his work. In cases of intraventricular rupture of a brain abscess, a neuroendoscopic approach is useful for evacuation of intraventricular debris or septum, and identification of the causative bacterium for selection of antibiotics, possibly reducing the period of hospitalization.

  12. Antecedents of perinatal cerebral white matter damage with and without intraventricular hemorrhage in very preterm newborns.

    Science.gov (United States)

    Logan, J Wells; Westra, Sjirk J; Allred, Elizabeth N; O'Shea, T Michael; Kuban, Karl; Paneth, Nigel; Leviton, Alan

    2013-08-01

    Isolated periventricular leukomalacia, defined as periventricular leukomalacia unaccompanied by intraventricular hemorrhage, is reportedly increased in newborns with systemic hypotension and in infants who received treatment for systemic hypotension or a patent ductus arteriosus. This study sought to determine if the risk profile of one or more hypoechoic lesions unaccompanied by intraventricular hemorrhage, our surrogate for isolated periventricular leukomalacia, differs from that of one or more hypoechoic lesions preceded or accompanied by intraventricular hemorrhage. We compared extremely preterm infants (i.e., gestation 23-27 weeks) with each of these entities to 885 extremely preterm infants who had neither an isolated hypoechoic lesion nor a hypoechoic lesion preceded or accompanied by intraventricular hemorrhage. The risk of a hypoechoic lesion with intraventricular hemorrhage (N = 61) was associated with gestation Acute Neonatal Physiology, early recurrent or prolonged acidemia, analgesic exposure, and mechanical ventilation 1 week after birth. In this large, multicenter sample of extremely low gestational age newborns, the risk profile of a hypoechoic lesion unaccompanied by intraventricular hemorrhage differed from that of a hypoechoic lesion with intraventricular hemorrhage. This suggests that hypoechoic lesions accompanied or preceded by intraventricular hemorrhage (our surrogate for periventricular hemorrhagic infarction) may have a different causal pathway than hypoechoic lesions without intraventricular hemorrhage, our surrogate for periventricular leukomalacia. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. A Tutorial on the Use of Excel 2010 and Excel for Mac 2011 for Conducting Delay-Discounting Analyses

    Science.gov (United States)

    Reed, Derek D.; Kaplan, Brent A.; Brewer, Adam T.

    2012-01-01

    In recent years, researchers and practitioners in the behavioral sciences have profited from a growing literature on delay discounting. The purpose of this article is to provide readers with a brief tutorial on how to use Microsoft Office Excel 2010 and Excel for Mac 2011 to analyze discounting data to yield parameters for both the hyperbolic…

  14. A case report on subarachnoid and intraventricular neurocysticercosis

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    Chen Shang

    2015-01-01

    Full Text Available Neurocysticercosis is the most common central nervous system helminthic infection in humans. We hereby present a case combining two rare manifestations of neurocysticercosis: the subarachnoid and intraventricular forms. The patient presented with hydrocephalus and neurologic deficits and although endoscopic removal of the cysts and two cycles of postoperative cysticidal drugs resulted in resolution of symptoms, they later recurred. Ventriculoperitoneal shunt placement and a further cycle of albendazole plus dexamethasone led to substantial clinical improvement. Extraparenchymal neurocysticercosis may be challenging to diagnose and treat and is usually associated with a poorer prognosis. Clinicians should be aware of this condition.

  15. Developmental Outcome of Preterm Infants with Intraventricular Hemorrhage at One and Two Years of Age.

    Science.gov (United States)

    Sostek, Anita Miller; And Others

    1987-01-01

    This study examined developmental outcome at 1 and 2 years in relation to the presence and severity of neonatal intraventricular hemorrhage. Intraventricular hemorrhage related to Bayley mental and motor scores and neurologic ratings at 1 year but not at 2 years. Significant associations were found between the 1- and 2-year measures but not…

  16. Altered expressions of endothelial junction protein of placental capillaries in premature infants with intraventricular hemorrhage

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    Maria Ekawati

    2016-10-01

    Full Text Available Background: Placental hypoxia may lead to oxidative stress, which inflicts damage to capillary protein junction. The aim of this study was to evaluate altered expression of endothelial junction protein of capillaries in hypoxia condition and to observe its correlation with the incidence of  intraventricular hemorrhage in premature infants.Methods: A cross-sectional study was conducted by using placental tissues of premature infants as amodel of capillary integrity (29 hypoxic and 29 non-hypoxic. Hypoxia inducible factor (HIF-1α was measured to define placental tissue response to hypoxia; malondialdehyde (MDA and glutathione (GSH served as markers of oxidative stress. The expressions of junctional proteins, N-cadherin and occludin were analyzed by immunohistochemistry. Intraventricular hemorrhage (IVH was detected by cranial ultrasound at the third day. Unpaired t test, Mann-Whitney, and Chi-square tests were used to analyze the data.Results: The HIF-1α and MDA levels were slightly, but not significantly, higher in hypoxia group {13.64±8.70 pg/mg protein and 10.31 pmol/mg tissue (ranged 1.92–93.61, respectively}  compared to non- hypoxia group {10.65±5.35 pg/mg protein and 9.77 pmol/mg tissue (ranged 2.42–93.31}. GSH levels were not different in both groups (38.14 (ranged 9.44–118.91 and  38.47(ranged 16.49–126.76 ng/mg protein, respectively. mRNA expression of N-cadherin (0.13 and occludin (0.096 were significantly lower in hypoxia comparedto non-hypoxia group (p=0,001, while protein expression of  N-cadherin (3.4; 75.9; 6.9; 13.8% and occludin  (20.7; 3.4; 69.0; 3.4; 6.9%  in hypoxia group was not associated with IVH (p=0.783 and p=0.743.Conclusion: Hypoxia altered expression of endothelial junction protein in placental capillaries, but no association with intraventricular hemorrhage was observed.

  17. Churg-Strauss syndrome associated with rapid deterioration of left ventricular diastolic dysfunction and conduction disturbance.

    Science.gov (United States)

    Chin, Jung Yeon; Yi, Jeong Eun; Youn, Ho-Joong

    2013-10-01

    Cardiac involvement in Churg-Strauss syndrome (CSS) is a major cause of mortality. Here we report a case of a 75-year-old woman with eosinophilic endomyocarditis due to CSS. An electrocardiogram showed intraventricular conduction delay, and echocardiography showed an impaired relaxation pattern and biventricular apical thickening. Magnetic resonance imaging revealed subendocardial delayed enhancement with biventricular apical thrombi. Endomyocardial biopsy showed perivascular eosinophilic infiltration. Despite resolution of the hypereosinophilia after steroid therapy, her left ventricular (LV) diastolic function worsened into a restrictive pattern and she died with a ventricular escape rhythm on her 14th day in the hospital. This case is unusual in that there was rapid progression of the LV diastolic dysfunction and conduction disturbance due to CSS. © 2013, Wiley Periodicals, Inc.

  18. Intraventricular Hemorrhage after Epidural Blood Patching: An Unusual Complication

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    Mohammad Sorour

    2014-01-01

    Full Text Available The authors present two cases of intraventricular hemorrhage (IVH believed to be a result of epidural blood patching. The first was a 71-year-old woman who had new onset of nontraumatic IVH on computed tomography (CT scan after undergoing an epidural blood patch (EBP. This amount of intraventricular blood was deemed an incidental finding since it was of very small volume to account for her overall symptoms. The second patient, a 29-year-old woman, was found to have nontraumatic IVH three days after undergoing an EBP. This was seen on CT scan of the head for workup of pressure-like headaches, nausea, vomiting, and absence seizures. Conservative management was followed in both instances. Serial CT scan of the head in our first patient displayed complete resolution of her IVH. The second patient did not have follow-up CT scans because her overall clinical picture had improved significantly. This highlights a potential sequel of EBP that may be observed on CT scan of the head. In the event that IVH is detected, signs and symptoms of hydrocephalus should be closely monitored with the consideration for a future workup if warranted by the clinical picture.

  19. [Twin pregnancy as the risk factor for neonatal intraventricular hemorrhage].

    Science.gov (United States)

    Wieczorek, Aleksandra I; Krasomski, Grzegorz

    2015-02-01

    The aim of this study was to find the perinatal risk factors of intravenricular hemorrhage in twin neonates. A retrospective analysis of 203 twin pregnancies and deliveries between 2003 and 2009 was performed. Then data according birth state and neonatal complications in 406 twins were analyzed. Twin outcome was compared with the outcome of 105 singletons born at the same time and at the same gestational age as twins. Intraventricular hemorrhage was diagnosed in 116/406 (29%) of twins. IVH was found two times more often in the analyzed group than in singletons born at the same gestational age (29% vs. 18%, p = 0,03). In 96% I and II grade hemorrhage was diagnosed and in 4% III and IV grade hemorrhage in the Papille scale was found. 1) Intraventricular hemorrhage is found more often in twins than in singleton neonates born at the same gestational age. 2) IVH in twins correlate with preterm birth and low birth weight. IVH occur more often in twins with birth weight discordance and with too small maternal weight gain.

  20. Analysis of angiographic findings in cerebral arteriovenous malformation with hemorrhage: comparison between intracerebral and intraventricular hemorrhage

    International Nuclear Information System (INIS)

    Kim, Jae Kyun; Kim, Joon Hyung; Kwon, Jin Sook; Yoon, Soo Woong; Lee, Ho Kyu; Choi, Choong Gon; Suh, Dae Chul

    1998-01-01

    The purpose of this study was to analyze the angioarchitectures of cerebral arteriovenous malformation (AVM) and to determine whether there was correlation between angioarchitectures and patterns of intracranial hemorrhage (intracerebral, intraventricular, and both) in cerebral AVM. One hundred and twenty-eight patients who between November 1989 and December 1994 suffered supratentorial AVM with intracranial hemorrhage were studied retrospectively. Among 128 patients, intracerebral and intraventricular hemorrhage were seen in 68(53%) and 24 patients(19%), respectively, while both types were seen in the remaining 36 (28%). We analyzed the angioarchitectual characteristics of AVM, namely nidi, feeding arteries and draining veins, in three hemorrhagic groups of patients with intracerebral hemorrhage, intraventricular hemorrhage and both. The X 2 test or Fisher's exact test was used for statistical analysis. A cortically located nidus was most common in patients with intracerebral hemorrhage, while a periventricular location was most common in those with intraventricular hemorrhage (p<0.001). Location in the corpus callosum, choroid plexus, or intraventricular area was more frequent in the intraventricular than the intracerebral hemorrhagic group (p<0.05). Superficial venous drainage was most common in patients with intracerebral hemorrhage (p<0.001), and deep venous drainage in those with intraventricular hemorrhage (p=3D0.001). The angioarchitectual characteristics of cerebral arteriovenous malformation correlate significantly with patterns of intracranial hemorrhage, and awareness of the type of hemorrhage could help to manage patients and determine prognosis.=20

  1. Intracerebral Hemorrhage with Intraventricular Extension—Getting the Prognosis Right Early

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    Christoph Stretz

    2017-08-01

    Full Text Available BackgroundEarly accurate outcome prognostication for patients with intracerebral hemorrhage (ICH and accompanying intraventricular hemorrhage (IVH is often challenging (1. Acute hydrocephalus often contributes to a poor clinical exam (2 and can portend significant morbidity and mortality (3. Accordingly, the inpatient neurologist may feel inclined to recommend limitations of care for an ICH patient admitted with a large IVH burden and poor exam.Case presentationWe present a patient with significant IVH and minimal ICH who deteriorated rapidly to coma after presentation. Despite this exam, an initially non-functioning diversion of cerebrospinal fluid (CSF and temporary halt of further attempts of CSF diversion in the setting of an early “do not resuscitate order,” our patient gradually improved and, with supportive ICU care and rehabilitation, was able to communicate and ambulate with assistance at 12 weeks.ConclusionPatients with ICH with IVH do have the capacity to improve dramatically even with relatively conservative management. Unless previous limitations of care exist, we recommend that early judgments of prognosis for patients with ICH and/or IVH should be delayed for at least 72 h until the patient’s clinical trajectory over time is better understood.

  2. [Giant racemose subarachnoid and intraventricular neurocysticercosis: A case report].

    Science.gov (United States)

    Sanchez-Larsen, Alvaro; Monteagudo, Maria; Lozano-Setien, Elena; Garcia-Garcia, Jorge

    2015-01-01

    Neurocysticercosis is the most frequent parasitic disease of the central nervous system. It is caused by the larvae of Taenia solium, which can affect different anatomical sites. In Spain there is an increasing prevalence mainly due to immigration from endemic areas. The extraparenchymal forms are less common, but more serious because they usually develop complications. Neuroimaging plays a major role in the diagnosis and follow-up of this disease, supported by serology and a compatible clinical and epidemiological context. First-line treatments are cysticidal drugs such as albendazole and praziquantel, usually coadministered with corticosteroids, and in some cases surgery is indicated. We here report a case of neurocysticercosis with simultaneous intraventricular and giant racemose subarachnoid involvement. Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Pituitary apoplexy presenting as an intraventricular hemorrhage: An infrequent neurovascular emergency

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    Gabriel Torrealba-Acosta, MD

    2017-12-01

    Full Text Available Pituitary macroadenomas may present with a pituitary apoplexy, commonly with associated hemorrhage, but rarely large enough to show an intraventricular bleeding. This is a case report of a 66-year-old woman with a 3-month history of headache, hyporexia, asthenia and altered consciousness. First evaluations showed a large intraventricular hemorrhage on CT scan that was initially misdiagnosed for an aneurysmal rupture etiology but later confirmed to be a pituitary apoplexy from a large pituitary adenoma. Intraventricular hemorrhage due to a pituitary apoplexy could be mistaken for an aneurysmal origin thus warranting for a careful evaluation of the sellar region.

  4. The role of 3D volumetric MR sequences in diagnosing intraventricular neurocysticercosis: preliminar results

    Directory of Open Access Journals (Sweden)

    Francisco Edward Frota Mont'Alverne Filho

    2011-02-01

    Full Text Available OBJECTIVE: The purpose of this paper was to investigate the role of two three-dimensional magnetic resonance (MRI sequences: enhanced spoiled gradient recalled echo (SPGR, and fast imaging employing steady-state acquisition (FIESTA in the evaluation of intraventricular neurocysticercosis cysts and scolices. METHOD: Seven neurocysticercosis patients suspected of presenting intraventricular lesions were evaluated by magnetic resonance imaging using enhanced SPGR, and FIESTA. RESULTS: Enhanced SPGR detected eight cystic lesions, with scolices in four. Contrast enhancement was observed in three cysts. FIESTA also detected eight cystic lesions with the presence of scolices in seven of those cystic lesions. Four patients presented parenchymal involvement, while the remaining three presented the racemose form. CONCLUSION: FIESTA and SPGR are sequences that can detect intraventricular cysts of neurocysticercosis, and FIESTA also is good for the detection of the scolex. Considering this information we suggest that FIESTA and SPGR should be included in the MRI protocol for the investigation of intraventricular neurocysticercosis.

  5. Impact of antenatal steroids on intraventricular hemorrhage in very-low-birth weight infants.

    Science.gov (United States)

    Wei, J C; Catalano, R; Profit, J; Gould, J B; Lee, H C

    2016-05-01

    To determine the association between antenatal steroids administration and intraventricular hemorrhage rates. We used cross-sectional data from the California Perinatal Quality Care Collaborative during 2007 to 2013 for infants ⩽32 weeks gestational age. Using multivariable logistic regression, we evaluated the effect of antenatal steroids on intraventricular hemorrhage, stratified by gestational age. In 25 979 very-low-birth weight infants, antenatal steroid use was associated with a reduction in incidence of any grade of intraventricular hemorrhage (odds ratio=0.68, 95% confidence interval: 0.62, 0.75) and a reduction in incidence of severe intraventricular hemorrhage (odds ratio=0.51, 95% confidence interval: 0.45, 0.58). This association was seen across gestational ages ranging from 22 to 29 weeks. Although current guidelines recommend coverage for preterm birth at 24 to 34 weeks gestation, our results suggest that treatment with antenatal steroids may be beneficial even before 24 weeks of gestational age.

  6. Fatal Intraventricular Hemorrhage After the Extracranial Carotid Artery Angioplasty and Stent Placement

    International Nuclear Information System (INIS)

    Krajickova, Dagmar; Krajina, Antonin; Nova, Marketa; Raupach, Jan

    2005-01-01

    We report on a 72-year-old female with an unusual intracranial bleeding complication after an extracranial carotid artery stenting procedure performed for a tight left ICA stenosis associated with contralateral carotid occlusion. Two hours after the procedure, the initial signs of intracranial bleeding appeared that led to the patient's demise 5 days later. A brain CT showed and autopsy proved massive intraventricular bleeding. To our knowledge, our case is only the second report of isolated reperfusion intraventricular hemorrhage post-CAS

  7. Temporal Lobe Encephalocele in the Lateral Recess of the Sphenoid Sinus Presenting with Intraventricular Tension Pneumocephalus

    OpenAIRE

    Ohkawa, Toshika; Nakao, Naoyuki; Uematsu, Yuji; Itakura, Toru

    2010-01-01

    A basal encephalocele often shows an insidious clinical course. Only two cases of temporal lobe encephalocele accompanied with tension pneumocephalus have previously been reported. In this paper, we describe a case of lateral sphenoid sinus encephalocele presenting with intraventricular tension pneumocephalus. A 54-year-old man was referred to our institution presenting with intraventricular tension pneumocephalus. He had undergone ventriculoperitoneal shunt placement for postmeningitis hydro...

  8. In vivo quantification of intraventricular hemorrhage in a neonatal piglet model using an EEG-layout based electrical impedance tomography array.

    Science.gov (United States)

    Tang, Te; Weiss, Michael D; Borum, Peggy; Turovets, Sergei; Tucker, Don; Sadleir, Rosalind

    2016-06-01

    Intraventricular hemorrhage (IVH) is a common occurrence in the days immediately after premature birth. It has been correlated with outcomes such as periventricular leukomalacia (PVL), cerebral palsy and developmental delay. The causes and evolution of IVH are unclear; it has been associated with fluctuations in blood pressure, damage to the subventricular zone and seizures. At present, ultrasound is the most commonly used method for detection of IVH, but is used retrospectively. Without the presence of adequate therapies to avert IVH, the use of a continuous monitoring technique may be somewhat moot. While treatments to mitigate the damage caused by IVH are still under development, the principal benefit of a continuous monitoring technique will be in investigations into the etiology of IVH, and its associations with periventricular injury and blood pressure fluctuations. Electrical impedance tomography (EIT) is potentially of use in this context as accumulating blood displaces higher conductivity cerebrospinal fluid (CSF) in the ventricles. We devised an electrode array and EIT measurement strategy that performed well in detection of simulated ventricular blood in computer models and phantom studies. In this study we describe results of pilot in vivo experiments on neonatal piglets, and show that EIT has high sensitivity and specificity to small quantities of blood (slope of the curve was consistent between measurements on different subjects. Linear discriminant analysis showed a false positive rate of 0%, and receiver operator characteristic analysis found area under curve values greater than 0.98 to administered volumes between 0.5, and 2.0 ml. We believe our study indicates that this method may be well suited to quantitative monitoring of IVH in newborns, simultaneously or interleaved with electroencephalograph assessments.

  9. A study of acute expired cases with intraventricular hemorrhage

    International Nuclear Information System (INIS)

    Ikeda, Yukio; Higuchi, Hiroshi; Ueda, Kenji; Kobayashi, Shiro; Yajima, Kouzo

    1981-01-01

    Prior to the introduction of the CT scan, the diagnosis of intraventricular hemorrhage (IVH) was very difficult. The CT scan has, though, been recognized to be extremely informative in the evaluation of IVH. During the first three years we have had experience with 91 cases of IVH diagnosed by the CT scan. Acute death within seven days occurred in 42 of these cases. Hypertension was the most common Acute death within seven days occurred in 42 of these cases. Hypertension was the most common etiological factor, accounting for 18 cases. Cerebral aneurysm was the second most common cause, accounting for 10 cases. Head injury was seen in 8 cases, while the causes of 4 deaths were unknown. 31 cases were distributed over all ventricles. 30 cases revealed over two cast formations. The presence of IVH in the third and/or the fourth ventricle, which can easily affect the function of the hypothalamus and the brain stem anatomically, was closely correlated with the high mortality rate. The analysis of the CT findings regarding the mechanisms of IVH reveals three types: the direct type, which bleeds directly into ventricles without forming definite intracerebral hematomas; the extension type, which is characterized by extension and rupture from massive intracerebral hematoma, and the reflux type, which is characterized by a reflux of the subarachnoid blood. The prognosis depends on the differences in these mechanisms. (author)

  10. Prognostic value of intraventricular bleeding in spontaneous intraparenchymal cerebral hemorrhage of small volume: a prospective cohort study.

    Science.gov (United States)

    Fortes Lima, Telmo Tiburcio; Prandini, Mirto Nelso; Gallo, Pasquale; Cavalheiro, Sérgio

    2012-04-01

    The literature is controversial on whether intraventricular bleeding has a negative impact on the prognosis of spontaneous intracerebral hemorrhage. Nevertheless, an association between intraventricular bleeding and spontaneous intracerebral hemorrhage volumes has been consistently reported. To evaluate the prognostic value of intraventricular bleeding in deep intraparenchymal hypertensive spontaneous hemorrhage with a bleeding volume bleeding was calculated by the LeRoux scale. Clinical data, including neurological complications, were collected daily during hospitalization. Neurological outcome was evaluated 30 days after the event by using the Glasgow outcome scale. Patients were assigned to 1 of 3 groups according to intraventricular bleeding: Control, no intraventricular bleeding; LR 1, intraventricular bleeding with LeRoux scale scores of 1 to 8; or LR 2, intraventricular bleeding with LeRoux scale scores >8. There were no significant differences among groups concerning age, mean blood pressure, and time from onset to brain CT scan. Patients with greater intraventricular bleeding presented lower initial Glasgow coma scale scores, increased ventricular index and width of temporal horns, increased number of clinical and neurological complications, and longer hospitalization. Furthermore, their relative risk for unfavorable clinical outcome was 1.9 (95% confidence interval 1.25-2.49). Intraventricular bleeding with a LeRoux scale score >8 appears to have a negative effect on deep spontaneous intraparenchymal cerebral hemorrhage of small volume.

  11. Peri-intraventricular hemorrhage in newborns weighing less than 1500 grams: comparative analysis between 2 institutions

    Directory of Open Access Journals (Sweden)

    Ponte Marinice Duarte da

    2003-01-01

    Full Text Available PURPOSE: This study aims to characterize the peri-intraventricular hemorrhages in the neonatal period in very low birth weight newborns in 2 institutions that provide neonatal tertiary assistance. METHOD: This was a comparative and observational study in 2 neonatal intensive care units, the Maternity Hospital of Campinas and the "Centro de Atenção Integrada à Saúde da Mulher" of the State University of Campinas, from December 01, 1998 to November 30, 1999. We examined 187 newborns for peri-intraventricular hemorrhages, using transfontanel ultrasound (76 and 11 respectively at the first and second unit, and classified them into 4 grades. We observed their gender, intrauterine growth, weight, and gestational age at birth. RESULTS: We diagnosed 34 cases of peri-intraventricular hemorrhages (13 and 21, respectively, and both groups differed as to the birth weight and the adequacy of weight to the gestational age at birth. There was no difference in the prevalence or extent of peri-intraventricular hemorrhages among cases. There was a statistically significant occurrence of lower birth weight at gestational ages of less than 30 weeks. CONCLUSIONS: The prevalence of peri-intraventricular hemorrhages in our study was compared to that reported in the world literature. Although the cases of the second institution had a smaller mean birth weight, the prevalence of peri-intraventricular hemorrhages was similar to that at the first institution, probably because in the first one, 69% of the gestational ages of the neonates with hemorrhage were less than 30 weeks as compared to 48% in the second one. We stress the importance of the ultrasonographic method for diagnosing peri-intraventricular hemorrhages in very low birth weight newborns.

  12. Ethamsylate in the prevention of periventricular-intraventricular hemorrhage in premature infants.

    Science.gov (United States)

    Chen, J Y

    1993-10-01

    A random and controlled trial was conducted to evaluate the efficacy and safety of ethamsylate in the prevention of periventricular-intraventricular hemorrhage (PIVH) in premature infants. Between January 1990 and July 1992, 171 premature infants with a birth weight of ethamsylate 12.5 mg/kg (0.1 mL/kg from 250 mg/2mL ampoules) was given to group 1 intravenously within an hour of delivery and was followed by doses at six-hourly intervals for four days (total dose 200 mg/kg). Group 2 consisted of 85 premature infants with mean birth weight of 1.4 +/- 0.3 kg and mean gestational age of 30.4 +/- 2.2 weeks. Group 2 received 0.1 mL/kg normal saline intravenously in a similar fashion as the ethamsylate-treated group. Cranial ultrasound examinations were performed on postnatal days one, two, three, five, seven and 14. The incidence of PIVH in the ethamsylate-treated group was 24/86 (27.9%) and 39/85 (45.9%) in the control group (p ethamsylate-treated group was 9/86 (10.5%) and 20/85 (23.5%) in the control group (p ethamsylate therapy in this study.

  13. Intraventricular haemorrhage in preterm infants--can we improve outcome by addressing coagulation?

    Science.gov (United States)

    Kuperman, Amir A; Brenner, Benjamin; Kenet, Gili

    2015-11-01

    During the last few decades, the survival of preterm infants has increased dramatically. Nevertheless, with the increasing number of very young and extremely low birth weight infants, morbidity is still a major problem. Intraventricular Haemorrhage (IVH) is a major complication of preterm birth, and large haemorrhages or haemorrhages associated with parenchymal brain lesions may yield a high rate of future disability. IVH is a complex, multi-factorial disorder. Prematurity and low birth weight remain as its most important risk factors, affecting vulnerability of the germinal matrix as well as the coagulation system. Approximately 80% of IVHs occur by 72 h after birth, but a considerable proportion of IVH is already visible on the first cranial ultrasound scan within a few hours of birth. The hypothesis that a severe coagulation deficiency in the premature newborn could be a major contributing factor to IVH has been suggested, and small open label interventional studies targeting the premature coagulation system have been conducted with ethamsylate, vitamin K, fresh frozen plasma, recombinant activated factor VII and prothrombin complex concentrate. The outcome of these studies will be reviewed.

  14. Effect of mitral orifice shape on intra-ventricular filling fluid dynamics

    Science.gov (United States)

    Okafor, Ikechukwu; Angirish, Yagna; Yoganathan, Ajit; Santhanakrishnan, Arvind

    2013-11-01

    The natural geometry of the mitral orifice is D-shaped. However, most current designs of prosthetic valves employ O-shaped orifice geometry. The goal of this study was to compare the effect of geometrical modification between the D and O orifice on the intra-ventricular fluid dynamics during diastolic filling. The different mitral orifice geometries were incorporated into an in vitro left heart simulator consisting of a flexible-walled anatomical left ventricle (LV) physical model enclosed in an acrylic housing. Physiological flow rates and pressures were obtained via tuning systemic resistance and compliance elements in the flow loop. A programmable piston pump was used to generate the LV model wall motion. 2D Particle image velocimetry measurements were conducted along multiple longitudinal planes perpendicular to the annulus plane. During peak diastole, the incoming jet width at the LV central plane was smaller for the D-orifice than that of the O-orifice. Further, the core of the vortex ring in the D-orifice was reduced in size compared to that of the O-orifice. The spatiotemporal spreading of the inflow jet as well as the propagation of the vortex ring will be discussed. This study was funded by a grant from the National Heart, Lung and Blood Institute (RO1HL70262).

  15. Beagle puppy model of intraventricular hemorrhage: ethamsylate studies.

    Science.gov (United States)

    Ment, L R; Stewart, W B; Duncan, C C

    1984-02-01

    Intraventricular hemorrhage (IVH) remains a major problem of preterm neonates, and ethamsylate, an inhibitor of specific prostaglandin-synthetic enzymes has been demonstrated to prevent IVH in these patients. We have examined the effects of ethamsylate on newborn beagle pups who were, by randomized computerized design, assigned to four cells consisting of (a) either ethamsylate or saline pretreatment and (b) either insulted or not insulted with hemorrhagic hypovolemia/volume re-expansion. Prostaglandin levels were obtained prior to and thirty minutes following administration of the solutions and 14C iodoantipyrine autoradiography was performed for cerebral blood flow (CBF) determinations. Ethamsylate produced a significant decrease in the incidence of IVH in this model (p less than 0.05). Following drug administration, ethamsylate-pretreated pups had significant declines in thromboxane B2 and 6-keto PGF1 alpha levels, the major breakdown products of thromboxane A2 and prostacyclin. Although ethamsylate significantly lowered baseline CBF in all brain regions examined in insulted and non-insulted pups (p less than 0.05), in the drug-treated group it did not prevent the changes seen in CBF to the germinal matrix region which were detected in the saline-pretreated pups. Nor did it significantly blunt the blood pressure changes in response to the hemorrhagic hypovolemia/volume re-expansion insult found in the latter group of animals. In addition, only ethamsylate pretreated pups had marked hypotensive responses to the reperfusion phase of the insult. Although the diminution of baseline CBF may contribute to the prevention of neonatal IVH which this drug has been demonstrated to exhibit, ethamsylate may also act as a capillary stabilizing agent.

  16. Intraventricular hemorrhage in the newborn and very young infant

    International Nuclear Information System (INIS)

    Takagi, Takuji; Togari, Hajime; Shimizu, Kuniki

    1980-01-01

    CT has been established as a rapid, safe and non-invasive technique for the diagnosis of neonatal intraventricular hemorrhage (IVH). It demonstrates the precise extent of IVH after birth. Eight infants with IVH (5 boys and 3 girls) were studied with CT using an EMI (1010) scanner. Five of the eight infants survived. Three infants (cases 1, 2 and 6) developed severe hydrocephalus. Shunting procedure were performed on these 3 cases, and they survived. The remainder (cases 3, 4, 7 and 8), examined within 5 days after the onset of symptoms, showed IVH. Cases 3, 7 and 8 died. Case 3 had an extensive hematoma in the right lateral ventricle, while case 7 and 8 had a hematoma forming a cast in the whole ventricular system. Case 5 and 6 had clots in the trigonum of both lateral ventricles. In cases 4, 5 and 6, spinal taps were performed frequently to reduce intracranial pressure, and CT was repeated one time a week. Case 4 showed no hydrocephalus. In case 5, the clots became smaller gradually and disappeared on the 25th day after birth. The lateral ventricles distended gradually. However, the distension was spontaneously arrested in this case. Case 6 showed progressive hydrocephalus despite repeated spinal taps, so V-P shunt was performed. But the shunt system was removed on the 14th postoperative day because of malfunction in the system. Thereafter he showed no hydrocephalus. Types of IVH are classified by CT findings into 4 groups: 1) showing hydrocephalus, 2) clotting observed in one ventricle, 3) clotting observed in 2 ventricles, 4) clotting observed throughout the ventricular system. Thus, CT provides useful diagnostic information about the presence, site and distension of the IVH. Its findings enable the physician to make an appropriate prognostic judgement. (author)

  17. Incidence of Intraventricular Hemorrhage and Post Hemorrhagic Hydrocephalus in Preterm Infants

    Directory of Open Access Journals (Sweden)

    Negar Sajjadian

    2010-07-01

    Full Text Available "nGerminal matrix-intraventricular hemorrhage (IVH is the most common variety of neonatal intracranial hemorrhage and is characteristics of the premature infant. The importance of the lesion relates not only to its high incidence but to their attendant complications (IC: hydrocephalus. Brain sonography is the procedure of choice in diagnosis of germinal matrix- intraventricular hemorrhage and hydrocephalus. In this study we have used brain sonography for detection of intraventricular hemorrhage and post hemorrhagic hydrocephalus and their incidences. The studied population was consisted of premature neonate (birth weight equal or less than 1500g and gestational age equal or less than 37 weeks who admitted in Mofid Hospital NICU (Tehran, Iran during a one year period. For all neonate (including criteria brain sonography in first week of life was done and in presence of IVH, serial Brain sonography was done weekly for detection of hydrocephalus. A total of 57 neonate entered the study. Intraventicular-germinal matrix hemorrhage was seen in 64.4% (35 patients. Forty percent of patients with intraventricular-germinal matrix hemorrhage had grade I, 11% grade II, 25.7% grade III, 2.8% grade VI. Hydrocephalus was detected in 20 percent of patients who had intraventricular-germinal matrix hemorrhage. That incidence of IVH in our study in comparison with other area and situation is higher. Hydrocephaly had direct relation with severity of IVH. This shows that with control of risk factor of IVH, we can control Post hemorrhagic hydrocephalus.

  18. Early neurodevelopment in very low birth weight infants with mild intraventricular hemorrhage or those without intraventricular hemorrhage

    Directory of Open Access Journals (Sweden)

    Il Rak Choi

    2012-11-01

    Full Text Available &lt;B&gt;Purpose:&lt;/B&gt; This study aimed to assess early development in very low birth weight (VLBW infants with mild intraventricular hemorrhage (IVH or those without IVH and to identify the perinatal morbidities affecting early neurodevelopmental outcome. &lt;B&gt;Methods:&lt;/B&gt; Bayley Scales of Infant Development-II was used for assessing neurological development in 49 infants with a birth weight &lt;1,500 g and with low grade IVH (?#167;rade II or those without IVH at a corrected age of 12 months. &lt;B&gt;Results:&lt;/B&gt; Among the 49 infants, 19 infants (38.8% showed normal development and 14 (28.6% showed abnormal mental and psychomotor development. Infants with abnormal mental development (n=14 were mostly male and had a longer hospitalization, a higher prevalence of patent ductus arteriosus (PDA and bronchopulmonary dysplasia (BPD, and were under more frequent postnatal systemic steroid treatment compared with infants with normal mental development (n=35, P&lt;0.05. Infants with abnormal psychomotor development (n=29 had a longer hospitalization and more associated PDA compared to infants with normal psychomotor development (n=20, P&lt;0.05. Infants with abnormal mental and psychomotor development were mostly male and had a longer hospitalization and a higher prevalence of PDA and BPD compared to infants with normal mental and psychomotor development (n=19, P&lt;0.05. Using multiple logistic regression analysis, a longer duration of hospitalization and male gender were found to be significant risk factors. &lt;B&gt;Conclusion:&lt;/B&gt; Approximately 62% of VLBW infants with low grade IVH or those without IVH had impaired early development.

  19. Intracerebral hemorrhage with intraventricular extension and no hydrocephalus may not increase mortality or severe disability.

    Science.gov (United States)

    Mahta, Ali; Katz, Paul M; Kamel, Hooman; Azizi, S Ausim

    2016-08-01

    This paper aimed to test the hypothesis that intraventricular extension of spontaneous intracerebral hemorrhage (ICH) in the absence of hydrocephalus is not associated with increased mortality or severe disability. We performed a retrospective consecutive cohort study of patients with primary spontaneous ICH who were admitted to a single institution. Multivariate logistic regression analysis was used to assess the association of each variable with functional outcome as measured by the modified Rankin Scale (mRS). A total of 164 patients met our inclusion criteria and were included in the study. Only hydrocephalus (p=0.002) and hematoma volume (p=0.006) were significantly associated with mortality or poor functional outcome (mRS of 3 to 6). In contrast, the presence of intraventricular hematoma was not independently associated with poor functional outcome. The presence of intraventricular extension of ICH in the absence of hydrocephalus may not increase mortality or disability. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Intraventricular catheter placement by electromagnetic navigation safely applied in a paediatric major head injury patient.

    Science.gov (United States)

    Aufdenblatten, Christoph Alexander; Altermatt, Stefan

    2008-09-01

    In the management of severe head injuries, the use of intraventricular catheters for intracranial pressure (ICP) monitoring and the option of cerebrospinal fluid drainage is gold standard. In children and adolescents, the insertion of a cannula in a compressed ventricle in case of elevated intracranial pressure is difficult; therefore, a pressure sensor is placed more often intraparenchymal as an alternative option. In cases of persistent elevated ICP despite maximal brain pressure management, the use of an intraventricular monitoring device with the possibility of cerebrospinal fluid drainage is favourable. We present the method of intracranial catheter placement by means of an electromagnetic navigation technique.

  1. Local cerebral glucose utilization in the beagle puppy model of intraventricular hemorrhage

    International Nuclear Information System (INIS)

    Ment, L.R.; Stewart, W.B.; Duncan, C.C.

    1982-01-01

    Local cerebral glucose utilization has been measured by means of carbon-14( 14 C)-autoradiography with 2-deoxyglucose in the newborn beagle puppy model of intraventricular hemorrhage. Our studies demonstrate gray matter/white matter differentiation of uptake of 14 C-2-deoxyglucose in the control pups, as would be expected from adult animal studies. However, there is a marked homogeneity of 14 C-2-deoxyglucose uptake in all brain regions in the puppies with intraventricular hemorrhage, possibly indicating a loss of the known coupling between cerebral blood flow and metabolism in this neuropathological condition

  2. Energy dynamics of the intraventricular vortex after mitral valve surgery.

    Science.gov (United States)

    Nakashima, Kouki; Itatani, Keiichi; Kitamura, Tadashi; Oka, Norihiko; Horai, Tetsuya; Miyazaki, Shohei; Nie, Masaki; Miyaji, Kagami

    2017-09-01

    Mitral valve morphology after mitral valve surgery affects postoperative intraventricular flow patterns and long-term cardiac performance. We visualized ventricular flow by echocardiography vector flow mapping (VFM) to reveal the impact of different mitral valve procedures. Eleven cases of mechanical mitral valve replacement (nine in the anti-anatomical and two in the anatomical position), three bioprosthetic mitral valve replacements, and four mitral valve repairs were evaluated. The mean age at the procedure was 57.4 ± 17.8 year, and the echocardiography VFM in the apical long-axis view was performed 119.9 ± 126.7 months later. Flow energy loss (EL), kinetic pressure (KP), and the flow energy efficiency ratio (EL/KP) were measured. The cases with MVR in the anatomical position and with valve repair had normal vortex directionality ("Clockwise"; N = 6), whereas those with MVR in the anti-anatomical position and with a bioprosthetic mitral valve had the vortex in the opposite direction ("Counterclockwise"; N = 12). During diastole, vortex direction had no effect on EL ("Clockwise": 0.080 ± 0.025 W/m; "Counterclockwise": 0.083 ± 0.048 W/m; P = 0.31) or KP ("Clockwise": 0.117 ± 0.021 N; "Counterclockwise": 0.099 ± 0.057 N; P = 0.023). However, during systole, the EL/KP ratio was significantly higher in the "Counterclockwise" vortex than that in the "Clockwise" vortex (1.056 ± 0.463 vs. 0.617 ± 0.158; P = 0.009). MVP and MVR with a mechanical valve in the anatomical position preserve the physiological vortex, whereas MVR with a mechanical valve in the anti-anatomical position and a bioprosthetic mitral valve generate inefficient vortex flow patterns, resulting in a potential increase in excessive cardiac workload.

  3. A case of pineal teratoma with intraventricular free fat on CT scan

    International Nuclear Information System (INIS)

    Uede, Teiji; Takaya, Satoru; Shinya, Toshiyuki; Tanabe, Sumiyoshi; Hashi, Kazuo; Sohma, Tsutomu.

    1986-01-01

    Detection of an intraventricular or intratumoral fat-fluid level on the plain craniograms has been known as a characteristic sign indicating the presence of intracranial teratomatous tumors. On CT scans, however, only thirteen cases have been previously reported to be found an intraventricular and/or subarachnoid free fat associated with spontaneous ruptures of these tumors. We reported a case of pineal teratoma with intraventricular free-fat seen on CT scans. A nine-year-old male with precocious puberty was admitted to our hospital complaining a moderate nonpulsatile headache. Neurological examinations were normal without signs of meningeal irritation. The serum and CSF titer of HCG were raised markedly. The laboratory data of the CSF were normal and there were no pathological cells in the CSF. The CT scans revealed a large heterogeneous mass containing multiple areas of negative density in the pineal region. There were negative density droplets in the bilateral frontal horn on the same CT scans indicating a presence of free fats. At surgery, an yellowish oily material was drained from the tumor, but there was no sign of meningitis over the cortical surface of the occipital lobe. An intraventricular free fat on CT scan have been reported in fourteen cases including ours following the first case described by Fawcitt in 1976. Although most of the cases presented headache, only two cases was diagnosed clinically as chemical meningitis. Pathological changes indicating granulomatous meningitis, however, were noted in five cases, all of them presenting seizure attacks. (author)

  4. Hypertrophic Cardiomyopathy Associated with Mid-cavity Obstruction and High Left Intraventricular Pressure

    Science.gov (United States)

    A. Bejiqi, Ramush; J. Retkoceri, Ragip; Sh. Bejiqi, Hana

    2011-01-01

    We report a case of a child, with a rare form of the idiopathic hypertrophic cardiomyopathy, associated with mid-cavity obstruction and high intraventricular peak pressure. Cardiomyopathy, diagnosed antenataly, was followed postnataly and, despite of a lot echocardiographic findings - the growing, development and clinical signs are minimal. PMID:23407799

  5. Hypertrophic Cardiomyopathy Associated with Mid-cavity Obstruction and High Left Intraventricular Pressure

    OpenAIRE

    A. Bejiqi, Ramush; J. Retkoceri, Ragip; Sh. Bejiqi, Hana

    2011-01-01

    We report a case of a child, with a rare form of the idiopathic hypertrophic cardiomyopathy, associated with mid-cavity obstruction and high intraventricular peak pressure. Cardiomyopathy, diagnosed antenataly, was followed postnataly and, despite of a lot echocardiographic findings - the growing, development and clinical signs are minimal.

  6. Clinical aspects and prognosis of intraventricular hemorrhage with cerebrovascular disease. CT findings and etiological analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Yukio; Nakazawa, Shozo; Higuchi, Hiroshi; Ueda, Kenji; Kouzo, [Nippon Medical School, Tokyo

    1982-10-01

    Intraventricular hemorrhage with cerebrovascular disease was identified in 81 cases and death occurred within seven days in 34 cases. Hypertension was the most common etiological factor, accounting for 40 of the 81 cases. Cerebral aneurysm was the second most common cause accounting for 27 cases, arteriovenous malformation accounted for 9 of the cases, and 5 were of other causes. Signs of primary or secondary brain stem dysfunction were mainly seen in cases with hypertension and aneurysm, while cases with arteriovenous malformation had benign courses. The mortality depended on the severity of intraventricular hemorrhage; i.e., the distribution, site, and the number of cast formation. The presence of intraventricular clot in the third and/or fourth ventricles was correlated with a high mortality rate, especially in cases accompanied by cast formation and third and fourth ventricular dilatation, which affects hypothalamus and brain stem function. Analysis of CT findings for the mechanism of intraventricular hemorrhage revealed three types: extension type, in which massive intracerebral hematomas extended and ruptured into ventricles; the direct type, which bled directly into ventricles without forming definite intracerebral hematomas; and the reflux type, which was characterized by reflux of the subarachnoid blood.

  7. Comparison of clinical outcomes of intraventricular hematoma between neuroendoscopic removal and extraventricular drainage

    International Nuclear Information System (INIS)

    Komatsu, Fuminari; Komatsu, Mika; Wakuta, Naoki; Oshiro, Shinaya; Tsugu, Hitoshi; Iwaasa, Mitsutoshi; Inoue, Tooru

    2010-01-01

    The efficacy of treatment for intraventricular hematoma by neuroendoscopic surgery and extraventricular drainage was compared in 10 patients with intraventricular hematoma and hydrocephalus who underwent neuroendoscopic surgery (endoscopic group), and eight patients with intraventricular hematoma and hydrocephalus treated with extraventricular drainage (EVD group). The outcomes in each group were assessed retrospectively using the Graeb scores on the pre- and postoperative computed tomography (CT), duration of extraventricular drainage, requirement for a shunt operation, and modified Rankin scale score at 12 months. The Graeb scores on the preoperative CT were not significantly different between the two groups, but the duration of catheter placement was significantly shorter (69.3%) in the endoscopic group (2.7 days) than in the EVD group (8.8 days). None of the patients in either group required a shunt procedure for communicating hydrocephalus 12 months after surgery. Neuroendoscopic removal is a safe and effective procedure for intraventricular hematoma. Advantages include rapid removal of hematoma in the ventricular systems and reliable improvement of non-communicating hydrocephalus in the acute phase. The procedure resulted in faster removal of the catheter in the postoperative period and earlier patient ambulation. (author)

  8. Parenchymal neurocutaneous melanosis in association with intraventricular dermoid and Dandy-walker variant: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Joo; Won, Yoo Dong; Kim, Ki Tae; Chang, Eun Deok; Huh, Pil Woo [The Catholic University of Korea, College of Medicine, Uijongbu (Korea, Republic of)

    2006-06-15

    Neurocutaneous melanosis (NCM) is a rare congenital disease that is characterized by the presence of large or multiple congenital melanocytic nevi and melanotic lesions of the central nervous system. We report here on the CT and MR imaging findings of an unusual case of NCM that was associated with intraventricular dermoid and Dandy-Walker malformation.

  9. Impact of Antenatal Steroids on Intraventricular Hemorrhage in Very Low Birth Weight Infants

    Science.gov (United States)

    Wei, Julia C.; Catalano, Ralph; Profit, Jochen; Gould, Jeffrey B.; Lee, Henry C.

    2016-01-01

    Objective To determine the association between antenatal steroids administration and intraventricular hemorrhage rates. Methods We used cross-sectional data from the California Perinatal Quality Care Collaborative during 2007-2013 for infants ≤ 32 weeks gestational age. Using multivariable logistic regression, we evaluated the effect of antenatal steroids on intraventricular hemorrhage, stratified by gestational age. Results In 25,979 very low birth weight infants, antenatal steroid use was associated with a reduction in incidence of any grade of intraventricular hemorrhage (odds ratio = 0.51, 95% confidence interval: 0.45, 0.58) and a reduction in incidence of severe intraventricular hemorrhage (odds ratio = 0.62, 95% confidence interval: 0.57, 0.67). This association was seen across gestational ages ranging from 22 to 29 weeks. Conclusions While current guidelines recommend coverage for preterm birth at 24 to 34 weeks gestation, our results suggest that treatment with antenatal steroids may be beneficial even before 24 weeks of gestational age. PMID:27010109

  10. Intraventricular Hemorrhage Due to Coagulopathy After Vitamin K Administration in a Preterm Infant With Maternal Crohn Disease

    OpenAIRE

    Kazumichi Fujioka; Sachiyo Fukushima; Kosuke Nishida; Kazumoto Iijima; Ichiro Morioka

    2017-01-01

    Intraventricular hemorrhage (IVH) is a devastating morbidity in preterm infants and can result in poor neurodevelopmental outcomes. Intraventricular hemorrhage usually occurs within 72 hours after birth; post–acute-phase IVH (>1 week after birth) is uncommon. Development of the hemostatic system in fetuses and neonates is an age-dependent evolving process, and the neonatal hemostatic system is characterized by low levels of vitamin K–dependent factors, with further reduction caused by prematu...

  11. Intraventricular Hemorrhage Due to Coagulopathy After Vitamin K Administration in a Preterm Infant With Maternal Crohn Disease

    OpenAIRE

    Fujioka, Kazumichi; Fukushima, Sachiyo; Nishida, Kosuke; Iijima, Kazumoto; Morioka, Ichiro

    2017-01-01

    Intraventricular hemorrhage (IVH) is a devastating morbidity in preterm infants and can result in poor neurodevelopmental outcomes. Intraventricular hemorrhage usually occurs within 72 hours after birth; post-acute-phase IVH (> 1 week after birth) is uncommon. Development of the hemostatic system in fetuses and neonates is an age-dependent evolving process, and the neonatal hemostatic system is characterized by low levels of vitamin K-dependent factors, with further reduction caused by premat...

  12. Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

    DEFF Research Database (Denmark)

    Sørensen, Line Carøe; Maroun, Lisa Leth; Borch, K.

    2008-01-01

    AIM: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. METHODS: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). CONCLUSION: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired Udgivelsesdato: 2008/11...

  13. Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

    DEFF Research Database (Denmark)

    Sorensen, Line C; Maroun, Lisa L; Borch, Klaus

    2008-01-01

    Aim: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. Methods: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). Conclusion: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired....

  14. Differential radioautographic visualization of central catecholaminergic neurons following intracisternal or intraventricular injection of tritiated norepinephrine

    International Nuclear Information System (INIS)

    Nowaczyk, T.; Pujol, J.F.; Valatx, J.L.; Bobillier, P.

    1978-01-01

    The differential [ 3 H]NE labeling of CA groups following cerebrospinal fluid (CSF) injection procedures seems to be accounted by the dynamics of CSF formation and circulation, which is similar in the rat to that known in man. Following intraventricular injection there was a lack of labeling of CA neurons located at a distance from the cerebrospinal cavities. Labeled neurons were also visualized outside known CA groups, questioning the nature and functional significance of these cells. (C.F.)

  15. Periventricular nodular heterotopia and bilateral intraventricular xanthogranulomas in 22q11.2 deletion syndrome

    Directory of Open Access Journals (Sweden)

    Moogeh Baharnoori

    2017-09-01

    Full Text Available 22q11.2 deletion syndrome (22q11DS is the most common pathogenic copy number variant in humans. Neuropsychiatric phenotypes, including schizophrenia, are prominent. Imaging studies of individuals with this syndrome show a variety of abnormalities that may indicate abnormal neuronal migration. Here we present the neuroimaging and neuropathologic features of a 22q11DS patient with bilateral periventricular nodular heterotopias (PNH and intraventricular xanthogranulomas that were identified by post-mortem examination.

  16. In situ cardiac perfusion reveals interspecific variation of intraventricular flow separation in reptiles.

    Science.gov (United States)

    Joyce, William; Axelsson, Michael; Altimiras, Jordi; Wang, Tobias

    2016-07-15

    The ventricles of non-crocodilian reptiles are incompletely divided and provide an opportunity for mixing of oxygen-poor blood and oxygen-rich blood (intracardiac shunting). However, both cardiac morphology and in vivo shunting patterns exhibit considerable interspecific variation within reptiles. In the present study, we develop an in situ double-perfused heart approach to characterise the propensity and capacity for shunting in five reptile species: the turtle Trachemys scripta, the rock python Python sebae, the yellow anaconda Eunectes notaeus, the varanid lizard Varanus exanthematicus and the bearded dragon Pogona vitticeps To simulate changes in vascular bed resistance, pulmonary and systemic afterloads were independently manipulated and changes in blood flow distribution amongst the central outflow tracts were monitored. As previously demonstrated in Burmese pythons, rock pythons and varanid lizards exhibited pronounced intraventricular flow separation. As pulmonary or systemic afterload was raised, flow in the respective circulation decreased. However, flow in the other circulation, where afterload was constant, remained stable. This correlates with the convergent evolution of intraventricular pressure separation and the large intraventricular muscular ridge, which compartmentalises the ventricle, in these species. Conversely, in the three other species, the pulmonary and systemic flows were strongly mutually dependent, such that the decrease in pulmonary flow in response to elevated pulmonary afterload resulted in redistribution of perfusate to the systemic circuit (and vice versa). Thus, in these species, the muscular ridge appeared labile and blood could readily transverse the intraventricular cava. We conclude that relatively minor structural differences between non-crocodilian reptiles result in the fundamental changes in cardiac function. Further, our study emphasises that functionally similar intracardiac flow separation evolved independently in

  17. Intraventricular mass lesions at magnetic resonance imaging: iconographic essay - part 2

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Felipe Damasio de; Reis, Fabiano; Guerra, Jose Guilherme Giocondo, E-mail: fdamasiocastro@gmail.com [Universidade Estadual de Campinas (Unicamp), Campinas, SP (Brazil)

    2014-07-15

    The present essay is illustrated with magnetic resonance images obtained at the authors’ institution over the past 15 years and discusses the main imaging findings of intraventricular tumor-like lesions (colloid cyst, oligodendroglioma, astroblastoma, lipoma, cavernoma) and of inflammatory/infectious lesions (neurocysticercosis and an atypical presentation of neurohistoplasmosis). Such lesions represent a subgroup of intracranial lesions with unique characteristics and some imaging patterns that may facilitate the differential diagnosis. (author)

  18. In vivo proton magnetic resonance spectroscopy of intraventricular tumours of the brain

    International Nuclear Information System (INIS)

    Majos, Carles; Aguilera, Carles; Cos, Monica; Camins, Angels; Samitier, Alex; Castaner, Sara; Sanchez, Juan J.; Candiota, Ana P.; Delgado-Goni, Teresa; Mato, David; Acebes, Juan J.; Arus, Carles

    2009-01-01

    The aim of this study was to assess the usefulness of proton MR spectroscopy in the diagnosis of intraventricular tumours. Fifty-two intraventricular tumours pertaining to 16 different tumour types were derived from our database. All cases had single-voxel proton MR spectroscopy performed at TE at both 30 and 136 ms at 1.5 T. The Mann-Whitney U test was used to search for the most discriminative datapoints each tumour type. Characteristic trends were found for some groups: high Glx and Ala in meningiomas (p<0.001 and p<0.01, respectively), high mobile lipids in metastasis (p<0.001), high Cho in PNET (p<0.001), high mI+Gly in ependymoma (p<0.001), high NAC (p<0.01) in the absence of the normal brain parenchyma pattern in colloid cysts, and high mI/Gly and Ala in central neurocytoma. Proton MR spectroscopy provides additional metabolic information that could be useful in the diagnosis of intraventricular brain tumors. (orig.)

  19. In vivo proton magnetic resonance spectroscopy of intraventricular tumours of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Majos, Carles; Aguilera, Carles [Hospital Universitari de Bellvitge, Institut de Diagnostic per la Imatge (IDI). Centre Bellvitge, L' Hospitalet de Llobregat, Barcelona (Spain); Biomateriales y Nanomedicina (CIBER-BBN), Centro de Investigacion Biomedica en Red en Bioingenieria, Cerdanyola del Valles (Spain); Cos, Monica; Camins, Angels; Samitier, Alex; Castaner, Sara; Sanchez, Juan J. [Hospital Universitari de Bellvitge, Institut de Diagnostic per la Imatge (IDI). Centre Bellvitge, L' Hospitalet de Llobregat, Barcelona (Spain); Candiota, Ana P.; Delgado-Goni, Teresa [Biomateriales y Nanomedicina (CIBER-BBN), Centro de Investigacion Biomedica en Red en Bioingenieria, Cerdanyola del Valles (Spain); Unitat de Bioquimica de Biociencies, Department de Bioquimica i Biologia Molecular, Cerdanyola del Valles (Spain); Mato, David [Hospital Universitari de Bellvitge, Department of Neurosurgery, L' Hospitalet de Llobregat, Barcelona (Spain); Acebes, Juan J. [Hospital Universitari de Bellvitge, Department of Neurosurgery, L' Hospitalet de Llobregat, Barcelona (Spain); Biomateriales y Nanomedicina (CIBER-BBN), Centro de Investigacion Biomedica en Red en Bioingenieria, Cerdanyola del Valles (Spain); Arus, Carles [Unitat de Bioquimica de Biociencies, Department de Bioquimica i Biologia Molecular, Cerdanyola del Valles (Spain); Biomateriales y Nanomedicina (CIBER-BBN), Centro de Investigacion Biomedica en Red en Bioingenieria, Cerdanyola del Valles (Spain)

    2009-08-15

    The aim of this study was to assess the usefulness of proton MR spectroscopy in the diagnosis of intraventricular tumours. Fifty-two intraventricular tumours pertaining to 16 different tumour types were derived from our database. All cases had single-voxel proton MR spectroscopy performed at TE at both 30 and 136 ms at 1.5 T. The Mann-Whitney U test was used to search for the most discriminative datapoints each tumour type. Characteristic trends were found for some groups: high Glx and Ala in meningiomas (p<0.001 and p<0.01, respectively), high mobile lipids in metastasis (p<0.001), high Cho in PNET (p<0.001), high mI+Gly in ependymoma (p<0.001), high NAC (p<0.01) in the absence of the normal brain parenchyma pattern in colloid cysts, and high mI/Gly and Ala in central neurocytoma. Proton MR spectroscopy provides additional metabolic information that could be useful in the diagnosis of intraventricular brain tumors. (orig.)

  20. Assessing delay discounting in mice

    OpenAIRE

    Mitchell, Suzanne H.

    2014-01-01

    Delay discounting (also intertemporal choice or impulsive choice) is the process by which delayed outcomes, such as delayed food delivery, are valued less than the same outcomes delivered immediately or with a shorter delay. This process is of interest because many psychopathologies, including substance dependence, pathological gambling, attention deficit hyperactivity disorder and conduct disorder, are characterized by heightened levels of delay discounting. Some of these disorders are herit...

  1. Study of intraventricular hemorrhage in VLBW neonates admitted in Al-Zahra Hospital, Tabriz, Iran.

    Science.gov (United States)

    Jodeiry, B; Heidarzadeh, M; Sahmani-Asl, S; Hoseini, M; Javaherizadeh, H; Eliasi, S; Abedini, K

    2012-01-01

    Intra-ventricular hemorrhage (IVH) is an important predictor of adverse neurodevelopmental outcome. IVH risk factor identification may conduct improvement of quality of care in neonatal intensive care units. The aim of the current study was to determine possible risk factors associated with IVH in VLBW neonates admitted in our hospital. All neonates with birth weight below 1500 gr admitted to NICU. Cranial ultrasonography was done for premature neonates weighed 1000 g, sonography was done in 7 days and 30 days of life respectively. If there is any conditions such as apnea, seizure, significant decrease in level of hemoglobin, increased head circumference, increased oxygen consumption, and other significant changes another sonography was done again. Exclusion criteria were cerebral malformations, metabolic disturbances, chromosomal anomalies, central nervous system infection, and genetic syndromes. Data was analyzed by SPSS ver 16.0 (SPSS Inc, Chicago, IL, USA). In this study 64 cases with IVH and without IVH were included. Mean of gestational age was 28.78 +/- 12.08. From neonates, 54.6% were boys and 45.4% were girls. Vaginal delivery and cesarean section was done in 56 (32.2%) and 118 (67.8%) cases respectively. Mean +/- SD of pH in cases with IVH and without IVH was 7.19 +/- 0.22 and 7.30 +/- 0.12 respectively (p = 0.001). Mean ISD of pco2 in cases with IVH and without IVH was 65.15 +/- 29.89 and 49.88 +/- 40.89 respectively(p = 0.001). Mean of 5th min APGAR score in patients required CPR was 7.36 +/- 1.57 and in patients without CPR was 8.68 +/- 1.25 (P = 0.001). From cases with IVH, hydrocephaly was detected in 20 cases. From cases without IVH, hydrocephaly was detected in 6 cases. Result of chi-square show significant correlation between IVH and prematurity (chi2 = 21.94, df=1, P preclampsia in mother was significantly higher in cases without IVH (chi-square, p < 0.05). PDA, pressure support, surfactant therapy, inotrop drug administration, vaginal delivery

  2. Ultrasonic Findings of Intraventricular Hemorrhage in Preterm Newborns in Shariati Hospital (1391-1392

    Directory of Open Access Journals (Sweden)

    L. Agha Ghazvieny

    2016-08-01

    Full Text Available Background and Objective: Intracranial hemorrhage (ICH can affect newborn of all gestational ages and often is clinically silent. Germinal matrix hemorrhage and intraventricular hemorrhage (GM-IVH is most common in the premature population. Estimated of frequency have changed over the last 20 years. Currently, large series report a 15% prevalence in infants 1250g at birth Material and Methods: All the newborns whom met the inclusion criteria were included in the study, they all had a brain sonography in the first 48 hrs after, and in case of finding any abnormality sonography was performed every week until discharge. For those who had a normal sonography, no further sonography was performed an expert pediatric radiologist performed the sonographies in sagittal and coronal planes the size of corpus collosum, lateral ventricles, inter hemispheric fissure and subarachnoid spaces were measured. (My lab 70 Esaote Abnormal cystic regions in white and grey matter were evaluated and abnormal findings were documented. Results: Finally, 100 cases were included in the study GMH had a frequency of 28(28% in our study. Among those with GMH 18 were male and 10 were female. There were no significant differences between the two sex groups in this regard. (P value=0.5.2, 7 of these infants were delivered through normal vaginal delivery and 21 through c/section. There was no significant difference between the two groups in this regard. (p value=0.010. Mean gestational age among the group with positive history of bleeding was 29 weeks and 31 weeks among those with negative history of bleeding. (p value=0.005. Mean birth weight with positive history of bleeding was 1292 gr and 1490 gr with no bleeding. (p value=0.035 in both groups the highest frequency belonged to first time pregnancies. (p value=0.667. Regarding the grade of bleeding, grade I with 23 cases (82.1% had the highest frequency, grade 3 and 4 each had cases (7.1% and grade 2 had 1 cases (3

  3. Neurodevelopmental and Behavioral Outcomes in Extremely Premature Neonates With Ventriculomegaly in the Absence of Periventricular-Intraventricular Hemorrhage.

    Science.gov (United States)

    Pappas, Athina; Adams-Chapman, Ira; Shankaran, Seetha; McDonald, Scott A; Stoll, Barbara J; Laptook, Abbot R; Carlo, Waldemar A; Van Meurs, Krisa P; Hintz, Susan R; Carlson, Martha D; Brumbaugh, Jane E; Walsh, Michele C; Wyckoff, Myra H; Das, Abhik; Higgins, Rosemary D

    2018-01-01

    Studies of cranial ultrasonography and early childhood outcomes among cohorts of extremely preterm neonates have linked periventricular-intraventricular hemorrhage and cystic periventricular leukomalacia with adverse neurodevelopmental outcomes. However, the association between nonhemorrhagic ventriculomegaly and neurodevelopmental and behavioral outcomes is not fully understood. To characterize the outcomes of extremely preterm neonates younger than 27 weeks' gestational age who experienced nonhemorrhagic ventriculomegaly that was detected prior to 36 weeks' postmenstrual age. This longitudinal observational study was conducted at 16 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Infants born prior to 27 weeks' gestational age in any network facility between July 1, 2006, and June 30, 2011, were included if they had a cranial ultrasonogram performed prior to 36 weeks' postmenstrual age. Comparisons were made between those with ventriculomegaly and those with normal cranial sonograms. Data analysis was completed from August 2013 to August 2017. The main outcome was neurodevelopmental impairment, defined as a Bayley Scales of Infant and Toddler Development III cognitive score less than 70, moderate/severe cerebral palsy, a Gross Motor Function Classification System score of level 2 or more, vision impairment, or hearing impairment. Secondary outcomes included Bayley Scales of Infant and Toddler Development III subscores, components of neurodevelopmental impairment, behavioral outcomes, and death/neurodevelopmental impairment. Logistic regression was used to evaluate the association of ventriculomegaly with adverse outcomes while controlling for potentially confounding variables and center differences as a random effect. Linear regression was used similarly for continuous outcomes. Of 4193 neonates with ultrasonography data, 300 had nonhemorrhagic ventriculomegaly (7%); 3045 had normal cranial

  4. Image-guided Ommaya reservoir insertion for intraventricular chemotherapy: a retrospective series.

    Science.gov (United States)

    Lau, Jonathan C; Kosteniuk, Suzanne E; Macdonald, David R; Megyesi, Joseph F

    2018-03-01

    Ayub Ommaya proposed a surgical technique for subcutaneous reservoir and pump placement in 1963 to allow access to intraventricular cerebrospinal fluid (CSF). Currently, the most common indication for Ommaya reservoir insertion (ORI) in adults is for patients with hematologic or leptomeningeal disorders requiring repeated injection of chemotherapy into the CSF space. Historically, the intraventricular catheter has been inserted blindly based on anatomical landmarks. The purpose of this study was to examine short-term complication rates with ORI with image guidance (IG) and without image guidance (non-IG). We retrospectively evaluated all operative cases of ORI from 2000 to 2014 by the senior author. Patient demographic data, surgical outcomes, and peri-operative complications were collected. Accurate placement and early (30-day) morbidity or mortality were considered primary outcomes. Fifty-five consecutive patients underwent ORI by the senior author over the study period (43.5 ± 16.6 years; 40.0% female). Indications for placement included acute lymphoblastic leukemia, diffuse large B-cell lymphoma, and leptomeningeal carcinomatosis. There were seven (12.7%) total complications: three (37.5%) with no-IG versus four (8.5%) with IG. Catheter malpositions were significantly higher in the non-IG group at 37.5% compared to 2.1%. Catheters were also more likely to require multiple passes with non-IG at 25% compare to 0% with IG. There were no early infections in either group. We demonstrate improved accuracy and decreased complications using an image-guided approach compared with a traditional approach. Our results support routine use of intra-operative image guidance for proximal catheter insertion in elective ORI for intraventricular chemotherapy.

  5. Traumatic Intraventricular Hemorrhage In Severe Blunt Head Trauma: A One Year Analysis

    Directory of Open Access Journals (Sweden)

    G.R. Bahadorkhan

    2006-05-01

    Full Text Available Background:High resolution CT scan has made early diagnosis of intraventricular hemorrhage (IVH easier. Posttraumatic intraventricular hemorrhage has been reported to a greater extent because of the CT scan. Methods:904 patients were admitted in the NSICU from March 2001 to March 2002 with severe closed head injury, of those only 31 patients with intraventricular hemorrhage (GCS less than 8 are reported herein and the mechanism involved is discussed. Results: Nine cases had intracerebral hemorrhage (contusional group, four cases in the frontal lobe, three cases in the temporal lobe and two cases in the parietal lobe. Nine cases (basal ganglia hemorrhage group had hemorrhage in basal ganglia, six in the caudate nucleus and three in the thalamus, all spreading into the ventricles. In thirteen cases the original site of hemorrhage could not be determined. In this group six cases had accompanying peri-brain stem hemorrhage (peri-brain stem hemorrhage group and different brain stem injury signs. Four cases had IVH less than 5 mL with or without minor intracranial lesions (minor intracranial lesion group. Accompanying major intracranial hemorrhage was found in sixteen cases, six cases had epidural hematoma, four cases had subdural hematoma, and seven had a combination of ASDH, EDH and contusional prarenchymal hemorrhages, all requiring primary surgical evacuation, and seven cases had different degrees of minor abnormalities (i.e. minor epidural hemorrhage, minor subdural hemorrhage,sub-arachnoid hemorrhage, minor cortical contusions or subdural effusions which did not need surgical intervention.Two cases had acute hydrocephalus and needed ventricular external drainage. Conclusion:Acceleration-deceleration impact along the long axis of the skull might be the possible mechanism in shearing injury to perforating vessels of the basal ganglia for early appearance of hemorrhage in the caudate nucleus and thalamus. Hemorrhage in basal ganglia and brain

  6. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  7. Quantification of intraventricular hemorrhage is consistent using a spherical sensitivity matrix

    Science.gov (United States)

    Tang, Te; Sadleir, Rosalind

    2010-04-01

    We have developed a robust current pattern for detection of intraventricular hemorrhage (IVH). In this study, the current pattern was applied on two realistic shaped neonatal head models and one head-shaped phantom. We found that a sensitivity matrix calculated from a spherical model gave us satisfactory reconstructions in terms of both image quality and quantification. Incorporating correct geometry information into the forward model improved image quality. However, it did not improve quantification accuracy. The results indicate that using a spherical matrix may be a more practical choice for monitoring IVH volumes in neonates.

  8. Hypertensive peaks in the pathogenesis of intraventricular hemorrhage in the newborn. Abolition by phenobarbitone sedation

    DEFF Research Database (Denmark)

    Wimberley, P D; Lou, H C; Pedersen, H

    1982-01-01

    that the large increases in arterial blood pressure which occur with both spontaneous motor activity and in association with nursing procedures, are an important cause of development of IVH in very low birth weight infants. An example is given to show that pressure peaks can be abolished by phenobarbitone......Mean arterial blood pressure (MABP) was measured continuously for 3 to 5 days after birth in 27 premature infants with a birth weight under 1500 g, and who required umbilical artery catheterisation. All had respiratory distress syndrome (RDS). Intraventricular hemorrhage (IVH) occurred in 9 infants...

  9. An intraventricular clear cell meningioma revealed by an inflammatory syndrome in a male adult: a case report.

    Science.gov (United States)

    Cassereau, J; Lavigne, C; Michalak-Provost, S; Ghali, A; Dubas, F; Fournier, H D

    2008-07-01

    Intraventricular meningiomas are infrequent intracranial tumors. Clinical symptoms are mainly due to an increased intracranial pressure or a direct pressure on the surrounding brain structures. Inflammatory syndrome was described in some patients with chordoid meningiomas. Here we report a case of right intraventricular clear cell meningioma in a 50-year-old man who presented with fever, headache, and inflammatory syndrome. Clinical and biological normalization was rapidly obtained after tumor removal. Immunohistochemical examination showed tumor cells and lymphocytes positivity for the pyrogenic cytokine interleukin-6, with a same intensity. To our knowledge, this is the first case described in the literature concerning an adult man with an intraventricular clear cell meningioma associated with a systemic inflammatory syndrome.

  10. Post-surgical meningitis due to multiresistant Acinetobacter baumannii. Effective treatment with intravenous and/or intraventricular colistin and therapeutic dilemmas.

    Science.gov (United States)

    Paramythiotou, E; Karakitsos, D; Aggelopoulou, H; Sioutos, P; Samonis, G; Karabinis, A

    2007-02-01

    Post-surgical meningitis and/or ventriculitis caused by Gram-negative bacteria may be difficult to treat due to the emergence of multiresistant strains. Two patients with multiresistant Acinetobacter baumannii central nervous system infection, successfully treated with either intravenous and/or intraventricular colistin are presented. Unresolved issues such as dose and duration of intraventricular colistin are discussed.

  11. Intraventricular ciprofloxacin usage in treatment of multidrug-resistant central nervous system infections: report of four cases

    Directory of Open Access Journals (Sweden)

    Ayse Karaaslan

    2014-12-01

    Full Text Available In recent years, multidrug-resistant microorganisms appear as important nosocomial pathogens which treatment is quite difficult. As sufficient drug levels could not be achieved in cerebrospinal fluid during intravenous antibiotic therapy for central nervous system infections and due to multidrug-resistance treatment alternatives are limited. In this study, four cases of central nervous system infections due to multidrug-resistant microorganisms who were successfully treated with removal of the devices and intraventricular ciprofloxacin are presented. In conclusion, intraventricular ciprofloxacin can be used for treatment of central nervous system infections if the causative microorganism is sensitive to the drug and no other alternative therapy is available.

  12. Prolonged hydrocephalus induced by intraventricular hemorrhage in rats is reduced by curcumin therapy.

    Science.gov (United States)

    Qi, Zhihua; Zhang, Huiqin; Fu, Chuhua; Liu, Xiao; Chen, Bo; Dang, Yanwei; Chen, Huayun; Liu, Lijun

    2017-01-10

    Prolonged hydrocephalus is a major cause of severe disability and death of intraventricular hemorrhage (IVH) patients. However, the therapeutic options to minimize the detrimental effects of post-hemorrhagic hydrocephalus are limited. Curcumin has been reported to confer neuroprotective effects in numerous neurological diseases and injuries, but its role in IVH-induced hydrocephalus has not been determined. The aim of present study was to determine whether curcumin treatment ameliorates blood brain barrier (BBB) damage and reduces the incidence of post-hemorrhagic hydrocephalus in IVH rat model. Autologous blood intraventricular injection was used to establish the IVH model. Our results revealed that repeated intraperitoneal injection of curcumin ameliorated IVH-induced learning and memory deficits as determined by Morris water maze and reduced the incidence of post-hemorrhagic hydrocephalus in a dose-dependent manner at 28 d post-IVH induction. Further, the increased BBB permeability and brain edema induced by IVH were significantly reduced by curcumin administration. In summary, these findings highlighted the important role of curcumin in improving neurological function deficits and protecting against BBB disruption via promoting the neurovascular unit restoration, and thus it reduced the severity of post-hemorrhagic hydrocephalus in the long term. It is believed that curcumin might prove to be an effective therapeutic component in prevent the post-IVH hydrocephalus in the near future. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Mechanism of Solder Joint Cracks in Anisotropic Conductive Films Bonding and Solutions: Delaying Hot-Bar Lift-Up Time and Adding Silica Fillers

    Directory of Open Access Journals (Sweden)

    Shuye Zhang

    2018-01-01

    Full Text Available Micron sizes solder metallurgical joints have been applied in a thin film application of anisotropic conductive film and benefited three general advantages, such as lower joint resistance, higher power handling capability, and reliability, when compared with pressure based contact of metal conductor balls. Recently, flex-on-board interconnection has become more and more popular for mobile electronic applications. However, crack formation of the solder joint crack was occurred at low temperature curable acrylic polymer resins after bonding processes. In this study, the mechanism of SnBi58 solder joint crack at low temperature curable acrylic adhesive was investigated. In addition, SnBi58 solder joint cracks can be significantly removed by increasing the storage modulus of adhesives instead of coefficient of thermal expansion. The first approach of reducing the amount of polymer rebound can be achieved by using an ultrasonic bonding method to maintain a bonding pressure on the SnBi58 solder joints cooling to room temperature. The second approach is to increase storage modulus of adhesives by adding silica filler into acrylic polymer resins to prevent the solder joint from cracking. Finally, excellent acrylic based SnBi58 solder joints reliability were obtained after 1000 cycles thermal cycling test.

  14. Delayed Ejaculation

    Science.gov (United States)

    ... cases, it is due to a combination of physical and psychological concerns. Psychological causes of delayed ejaculation include: Depression, anxiety or other mental health conditions Relationship problems due to stress, poor communication ...

  15. Delayed growth

    Science.gov (United States)

    ... Slow rate of growth; Retarded growth and development; Growth delay Images Toddler development References Cooke DW, Divall SA, Radovick S. Normal and aberrant growth in children. In: Melmed S, Polonsky KS, Larsen PR, ...

  16. Rapid Pore Cranial Drilling With External Ventricular Drainage for Treatment of Intraventricular Hemorrhage: A 36-Year Case Series.

    Science.gov (United States)

    Zhang, Wei; Wei, Lin; Li, Gang; Sun, Jinlong; Jin, Peng; Yang, Jun; Wang, Daokui; Bai, Yunan; Li, Xingang; Fei, Chang; Wang, Chengwei; Wang, Baoan; Pan, Shumao; Du, Jihai; Xie, Bo; Xu, Dongfang; Xin, Changming; Wang, Jihua; Zhang, Qinglin

    2015-06-01

    This study aimed to describe the technique details of rapid pore cranial drilling with external ventricular drainage and document its clinical outcomes by highlighting the advantages over the traditional and modified cranial drilling technique. Intraventricular hemorrhage is one of the most severe subtypes of hemorrhagic stroke with high mortality. The amount of blood in the ventricles is associated with severity of outcomes, and fast removal of the blood clot is the key to a good prognosis. Between 1977 and 2013, 3773 patients admitted for intraventricular hemorrhage underwent rapid pore cranial drilling drainage. The therapeutic effects and clinical outcomes were retrospectively analyzed. Of these patients, 1049 (27.8%) experienced complete remission, 1788 (47.4%) had improved condition, and 936 (24.8%) died. A total of 3229 (85.6%) patients gained immediate remission. One typical case was illustrated to demonstrate the efficacy of the rapid pore drilling technique. Rapid pore cranial drilling drainage in patients with intraventricular hemorrhage is fast, effective, and provides immediate relief in patients with severe conditions. It could be a better alternative to the conventional drilling approach for treatment of intraventricular hemorrhage. A randomized controlled trial for direct comparison between the rapid pore cranial drilling drainage and conventional drilling technique is in urgent need.

  17. Alteplase (rtPA) treatment of intraventricular hematoma (IVH): safety of an efficient methodological approach for rapid clot removal

    DEFF Research Database (Denmark)

    Bartek, Jiri Jr.; Hansen-Schwartz, J; Bergdal, Ove Ketil

    2011-01-01

    Intraventricular hemorrhage (IVH) subsequent to intracerebral hemorrhage (ICH) or subarachnoid hemorrhage (SAH) is associated with high mortality and morbidity. The use of fibrinolytic agents to treat this condition has previously been reported in small clinical trials with limited numbers of pat...

  18. High-field spin-echo MR imaging of superficial and subependymal siderosis secondary to neonatal intraventricular hemorrhage

    International Nuclear Information System (INIS)

    Gomori, J.M.; Grossman, R.I.; Goldberg, H.I.; Zimmerman, R.A.; Bilaniuk, L.T.

    1987-01-01

    Two cases of superficial siderosis with subependymal siderosis, secondary to neonatal intraventricular hemorrhage, are presented. High-field spin-echo MR imaging (1.5 Tesla) showed marginal hypointensity of the ventricular walls as well as of the subpial regions. These findings were most evident on T 2 weighted images, characteristic of hemosiderotic deposits. (orig.)

  19. Neuroendoscopic Resection of Intraventricular Tumors and Cysts through a Working Channel with a Variable Aspiration Tissue Resector: A Feasibility and Safety Study

    Directory of Open Access Journals (Sweden)

    Edjah Kweku-Ebura Nduom

    2013-01-01

    Full Text Available Pure neuroendoscopic resection of intraventricular lesions through a burr hole is limited by the instrumentation that can be used with a working channel endoscope. We describe a safety and feasibility study of a variable aspiration tissue resector, for the resection of a variety of intraventricular lesions. Our initial experience using the variable aspiration tissue resector involved 16 patients with a variety of intraventricular tumors or cysts. Nine patients (56% presented with obstructive hydrocephalus. Patient ages ranged from 20 to 88 years (mean 44.2. All patients were operated on through a frontal burr hole, using a working channel endoscope. A total of 4 tumors were resected in a gross total fashion and the remaining intraventricular lesions were subtotally resected. Fifteen of 16 patients had relief of their preoperative symptoms. The 9 patients who presented with obstructive hydrocephalus had restoration of cerebrospinal fluid flow though one required a ventriculoperitoneal shunt. Three patients required repeat endoscopic resections. Use of a variable aspiration tissue resector provides the ability to resect a variety of intraventricular lesions in a safe, controlled manner through a working channel endoscope. Larger intraventricular tumors continue to pose a challenge for complete removal of intraventricular lesions.

  20. Tranport of p-aminohippuric acid (3H-PAH), inulin and dextran out of the cranial cavity: A methodological study using intraventricular injection and sample combustion

    International Nuclear Information System (INIS)

    Jakobson, Aa. M.

    1987-01-01

    Material injected into the cerebral ventricles can leave the cerebrospinal fluid (CSF) but remain in the cranial cavity. To analyze the disappearance of 3 H- and of 14 C-labelled material from the cranial cavity, such material was injected into the lateral ventricles together with a bulk flow marker, labelled with the other radionuclide. In the present pilot study 3 H-PAH and 14 C-inulin were used. Five μl of a mixture was injected into each lateral cerebral ventricles in rats, which were killed at various intervals. The whole skull was analyzed without opening the CSF space after homogenization in the deep-frozen state. The samples were combusted and analyzed by liquid scintillation counting. Probenecid, injected intraperitoneally, inhibited the removal of 3 H-PAH from the skull cavity, as anticipated. Immediately after the intraventricular injection, however, 3 H-PAH was transiently retained, probably by uptake into actively transporting tissue. After injection of probenecid, this delay in removal was reduced. The difference in disappearance rate between 3 H-PAH and 14 C-inulin was estimated by comparing the 3 H/ 14 C ratio in the skulls with that in the injected solution, which appeared to be a better method than comparing the recovery of each compound. (author)

  1. Automated processing of dynamic properties of intraventricular pressure by computer program and electronic circuit.

    Science.gov (United States)

    Adler, D; Mahler, Y

    1980-04-01

    A procedure for automatic detection and digital processing of the maximum first derivative of the intraventricular pressure (dp/dtmax), time to dp/dtmax(t - dp/dt) and beat-to-beat intervals have been developed. The procedure integrates simple electronic circuits with a short program using a simple algorithm for the detection of the points of interest. The tasks of differentiating the pressure signal and detecting the onset of contraction were done by electronics, while the tasks of finding the values of dp/dtmax, t - dp/dt, beat-to-beat intervals and all computations needed were done by software. Software/hardware 'trade off' considerations and the accuracy and reliability of the system are discussed.

  2. Quantification of intraventricular hemorrhage with electrical impedance tomography using a spherical model

    International Nuclear Information System (INIS)

    Tang, T; Sadleir, R J

    2011-01-01

    We have developed a robust EEG-based current pattern which shows promise for the detection of intraventricular hemorrhage (IVH) in neonates. Our reconstructions to date are based on a layered spherical head model. In this study, the current pattern was used to gather data from three realistic-shaped neonatal head models and a physical phantom based on one of these models. We found that a sensitivity matrix calculated from a spherical model gave us satisfactory reconstructions in terms of both image quality and quantification. Incorporating correct geometry information into the forward model improved image quality. However, it did not improve quantification accuracy. The results indicate that using a spherical matrix may be a more practical choice for monitoring IVH volumes in neonates for whom patient-specific models are not available

  3. Phase Image Analysis in Conduction Disturbance Patients

    International Nuclear Information System (INIS)

    Kwark, Byeng Su; Choi, Si Wan; Kang, Seung Sik; Park, Ki Nam; Lee, Kang Wook; Jeon, Eun Seok; Park, Chong Hun

    1994-01-01

    It is known that the normal His-Purkinje system provides for nearly synchronous activation of right (RV) and left (LV) ventricles. When His-Purkinje conduction is abnormal, the resulting sequence of ventricular contraction must be correspondingly abnormal. These abnormal mechanical consequences were difficult to demonstrate because of the complexity and the rapidity of its events. To determine the relationship of the phase changes and the abnormalities of ventricular conduction, we performed phase image analysis of Tc-RBC gated blood pool scintigrams in patients with intraventricular conduction disturbances (24 complete left bundle branch block (C-LBBB), 15 complete right bundle branch block (C-RBBB), 13 Wolff-Parkinson-White syndrome (WPW), 10 controls). The results were as follows; 1) The ejection fraction (EF), peak ejection rate (PER), and peak filling rate (PFR) of LV in gated blood pool scintigraphy (GBPS) were significantly lower in patients with C-LBBB than in controls (44.4 ± 13.9% vs 69.9 ± 4.2%, 2.48 ± 0.98 vs 3.51 ± 0,62, 1.76 ± 0.71 vs 3.38 ± 0.92, respectively, p<0.05). 2) In the phase angle analysis of LV, Standard deviation (SD), width of half maximum of phase angle (FWHM), and range of phase angle were significantly increased in patients with C-LBBB than in controls (20.6 + 18.1 vs S.6 + I.8, 22. 5 + 9.2 vs 16.0 + 3.9, 95.7 + 31.7 vs 51.3 + 5.4, respectively, p<0.05). 3) There was no significant difference in EF, PER, PFR between patients with the WolffParkinson-White syndrome and controls. 4) Standard deviation and range of phase angle were significantly higher in patients with WPW syndrome than in controls (10.6 + 2.6 vs 8.6 + 1.8, p<0.05, 69.8 + 11.7 vs 51.3 + 5 4, p<0.001, respectively), however, there was no difference between the two groups in full width of half maximum. 5) Phase image analysis revealed relatively uniform phase across the both ventriles in patients with normal conduction, but markedly delayed phase in the left ventricle

  4. Phase Image Analysis in Conduction Disturbance Patients

    Energy Technology Data Exchange (ETDEWEB)

    Kwark, Byeng Su; Choi, Si Wan; Kang, Seung Sik; Park, Ki Nam; Lee, Kang Wook; Jeon, Eun Seok; Park, Chong Hun [Chung Nam University Hospital, Daejeon (Korea, Republic of)

    1994-03-15

    It is known that the normal His-Purkinje system provides for nearly synchronous activation of right (RV) and left (LV) ventricles. When His-Purkinje conduction is abnormal, the resulting sequence of ventricular contraction must be correspondingly abnormal. These abnormal mechanical consequences were difficult to demonstrate because of the complexity and the rapidity of its events. To determine the relationship of the phase changes and the abnormalities of ventricular conduction, we performed phase image analysis of Tc-RBC gated blood pool scintigrams in patients with intraventricular conduction disturbances (24 complete left bundle branch block (C-LBBB), 15 complete right bundle branch block (C-RBBB), 13 Wolff-Parkinson-White syndrome (WPW), 10 controls). The results were as follows; 1) The ejection fraction (EF), peak ejection rate (PER), and peak filling rate (PFR) of LV in gated blood pool scintigraphy (GBPS) were significantly lower in patients with C-LBBB than in controls (44.4 +- 13.9% vs 69.9 +- 4.2%, 2.48 +- 0.98 vs 3.51 +- 0,62, 1.76 +- 0.71 vs 3.38 +- 0.92, respectively, p<0.05). 2) In the phase angle analysis of LV, Standard deviation (SD), width of half maximum of phase angle (FWHM), and range of phase angle were significantly increased in patients with C-LBBB than in controls (20.6 + 18.1 vs S.6 + I.8, 22. 5 + 9.2 vs 16.0 + 3.9, 95.7 + 31.7 vs 51.3 + 5.4, respectively, p<0.05). 3) There was no significant difference in EF, PER, PFR between patients with the WolffParkinson-White syndrome and controls. 4) Standard deviation and range of phase angle were significantly higher in patients with WPW syndrome than in controls (10.6 + 2.6 vs 8.6 + 1.8, p<0.05, 69.8 + 11.7 vs 51.3 + 5 4, p<0.001, respectively), however, there was no difference between the two groups in full width of half maximum. 5) Phase image analysis revealed relatively uniform phase across the both ventriles in patients with normal conduction, but markedly delayed phase in the left ventricle

  5. Neurocitoma central com apresentação incomum por hemorragia intraventricular: relato de caso

    Directory of Open Access Journals (Sweden)

    Hanel Ricardo Alexandre

    2001-01-01

    Full Text Available O neurocitoma central foi descrito pela primeira vez na literatura em 1982 por Hassoun e colaboradores como tumor bem diferenciado de origem neuronal. O tumor geralmente localiza-se no sistema ventricular, afetando adultos jovens e geralmente cursando com hipertensão intracraniana secundária à hidrocefalia obstrutiva. O diagnóstico diferencial com outros processos intraventriculares como oligodendroglioma é realizado através de métodos imuno-histoquímicos. Raros casos de neurocitoma central associados com hemorragia têm sido descritos na literatura. Descrevemos um caso de neurocitoma central de uma paciente de 35 anos com apresentação atípica. A paciente havia procurado o hospital com quadro súbito de cefaléia, vômitos e rigidez de nuca, sugerindo a presença de hemorragia subaracnóidea. A ressonância magnética demonstrou volumosa massa no ventrículo lateral direito cujos perfis histológico e imuno-histoquímico eram condizentes com neurocitoma central, a ressecção cirúrgica foi realizada com sucesso, embora a paciente tenha evoluído para um quadro de ventriculite no pós-operatório. Salientamos a importância do estabelecimento do neurocitoma central como diagnóstico diferencial de pacientes com hemorragia intraventricular e discutimos as opções de tratamento para este tumor incomum.

  6. CT findings and prognosis of spontaneous (hypertensive) intracerebralhematoma associated with intraventricular perforation

    International Nuclear Information System (INIS)

    Sogabe, Koichiro; Gyoten, Tetsuya; Masuda, Tsutomu; Hondo, Hideki; Matsumoto, Keizo

    1982-01-01

    The prognosis of spontaneous hypertensive intracerebral hematoma associated with the intraventricular hemorrhage were discussed with the base of computerized tomography (CT) findings in their acute stage. 104 (47%) out of 219 patients with hypertensive intracerebral hemorrhage revealed intraventricular hemorrhage in our service from January 1978 to December 1980. In these cases infratentorial, cerebellar and pontine hemorrhage were not included. Namely, 22 out of 93 cases of putaminal hemorrhage, 47 out of 61 cases in thalamic type, 30 out of 39 cases in combined type and 5 out of 26 cases in subcortical type were demonstrated the ventricular hemorrhage by CT examination, respectively. In early period of CT utilization, the ventricular hemorrhage had generally been accepted as one of serious signs from the knowledges, which had been obtained from postmortem examination in such cases. Recent experiences, however, suggested that cases of intracerebral hematoma with the ventricle rupture were not always resulted to the poor prognosis. Cases, which had extension of the hematoma to the 3rd and 4th ventricle, were clearly divided into two contradictory group, namely, poor and good prognostic group. They showed nearly equal occurance. However, it was noted that cases with the cast formation below the third ventricle resulted poor prognosis. Statistical analysis of our cases led the following conclusions i.e. the influencing factors of the poor outcome are: hematoma size is larger than 3x3 cm, combination of acute ventricular enlargement, disappearance of the ambient cistern and hypothalamic extension of hematoma; cast formation of blood in the 3rd and 4th ventricle. (J.P.N.)

  7. Developmental delay

    Science.gov (United States)

    Nutrition support is essential for the care of the child with developmental delay. After a thorough evaluation, an individualized intervention plan that accounts for the child’s nutrition status, feeding ability, and medical condition may be determined. Nutrition assessments may be performed at leas...

  8. Intraventricular Hemorrhage Due to Coagulopathy After Vitamin K Administration in a Preterm Infant With Maternal Crohn Disease

    Directory of Open Access Journals (Sweden)

    Kazumichi Fujioka

    2017-12-01

    Full Text Available Intraventricular hemorrhage (IVH is a devastating morbidity in preterm infants and can result in poor neurodevelopmental outcomes. Intraventricular hemorrhage usually occurs within 72 hours after birth; post–acute-phase IVH (>1 week after birth is uncommon. Development of the hemostatic system in fetuses and neonates is an age-dependent evolving process, and the neonatal hemostatic system is characterized by low levels of vitamin K–dependent factors, with further reduction caused by prematurity. Importantly, a severe coagulation deficiency can be a major contributing factor of IVH. Active maternal Crohn disease (CD during pregnancy causes malnutrition via enteral malabsorption; this may include vitamin K deficiency, resulting in fetal vitamin K deficiency. We herein describe a preterm infant who was born to a mother with CD and developed post–acute-phase IVH due to coagulopathy despite vitamin K administration.

  9. Conduction Abnormalities and Pacemaker Implantations After SAPIEN 3 Vs SAPIEN XT Prosthesis Aortic Valve Implantation.

    Science.gov (United States)

    Husser, Oliver; Kessler, Thorsten; Burgdorf, Christof; Templin, Christian; Pellegrini, Costanza; Schneider, Simon; Kasel, Albert Markus; Kastrati, Adnan; Schunkert, Heribert; Hengstenberg, Christian

    2016-02-01

    Transcatheter aortic valve implantation is increasingly used in patients with aortic stenosis. Post-procedural intraventricular conduction abnormalities and permanent pacemaker implantations remain a serious concern. Recently, the Edwards SAPIEN 3 prosthesis has replaced the SAPIEN XT. We sought to determine the incidences of new-onset intraventricular conduction abnormalities and permanent pacemaker implantations by comparing the 2 devices. We analyzed the last consecutive 103 patients undergoing transcatheter aortic valve implantation with SAPIEN XT before SAPIEN 3 was used in the next 105 patients. To analyze permanent pacemaker implantations and new-onset intraventricular conduction abnormalities, patients with these conditions at baseline were excluded. Electrocardiograms were recorded at baseline, after the procedure, and before discharge. SAPIEN 3 was associated with higher device success (100% vs 92%; P=.005) and less paravalvular leakage (0% vs 7%; Ppacemaker implantations was 12.6% (23 of 183) with no difference between the 2 groups (SAPIEN 3: 12.5% [12 of 96] vs SAPIEN XT: 12.6% [11 of 87]; P=.99). SAPIEN 3 was associated with a higher rate of new-onset intraventricular conduction abnormalities (49% vs 27%; P=.007) due to a higher rate of fascicular blocks (17% vs 5%; P=.021). There was no statistically significant difference in transient (29% [20 of 69] vs persistent 19% [12 of 64]; P=.168) left bundle branch blocks (28% [19 of 69] vs 17% [11 of 64]; P=.154) when SAPIEN 3 was compared with SAPIEN XT. We found a trend toward a higher rate of new-onset intraventricular conduction abnormalities with SAPIEN 3 compared with SAPIEN XT, although this did not result in a higher permanent pacemaker implantation rate. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  10. In vivo behavior of 111In-DTPA in rat and mouse after intra-ventricular administration

    International Nuclear Information System (INIS)

    Matsushima, Hiroaki; Kato, Makoto; Sugimura, Yukiharu; Hazue, Masaaki

    1977-01-01

    In vivo behavior of 111 In-DTPA in rat and mouse after intra-ventricular administration was studied. Thus, 50μCi and 35μCi of 111 In-DTPA was injected intraventricularly to rat and mouse respectively. At specific time intervals, the animals were sacrificed, then distribution in organs was determined by radioactivity counting and autoradiographic method. Urinary and fecal excretion were separately collected and excretion rates were estimated. Metabolites in urine of rat were examined with chromatography. A part of 111 In-DTPA injected intra-ventricularly to the animals migrated to subarachnoid space, then radioactivity in cerebrospinal fluid effused into blood with about 1 hr initial half-life. Blood clearance was also rapid, about 1 hr after administration the blood level reached maximum and then decreased showing an initial half-life of about 1 hr. The predominant excretion route in rat was urinary and about 90% and 5% of administered dose were excreted within 48 hr through urine and feces respectively. Judging from the Rf-value of radioactivity peak on chromatograms, 111 In-DTPA seems to be excreted without suffering any metabolic change. Concerning to the behavior of 111 In-DTPA in male and female rat, no difference was observed, and the distribution pattern of 111 In-DTPA in mouse was similar to that of rat. (auth.)

  11. Delayed Puberty

    DEFF Research Database (Denmark)

    Kolby, Nanna; Busch, Alexander Siegfried; Juul, Anders

    2017-01-01

    . The underlying reasons for the large variation in the age at pubertal onset are not fully established; however, nutritional status and socioeconomic and environmental factors are known to be influencing, and a significant amount of influencing genetic factors have also been identified. The challenges...... optimal in discriminating especially CDGP from HH. Management of the delayed puberty depends on the etiology. For boys with CDGP an observational period will often reveal imminent puberty. If puberty is not progressing spontaneously, sex steroid replacement is effective in stimulating the development...

  12. Primary Intraventricular Leiomyoma in an Immunocompetent Patient: First Case Report and Review of the Literature.

    Science.gov (United States)

    Garces, Juanita; Mathkour, Mansour; Valle-Giler, Edison; Scullen, Tyler; Berry, J Franklin; Smith, Roger D

    2016-06-01

    Primary intracranial leiomyoma is an extremely rare occurrence of a low-grade mesenchymal tumor characterized by a proliferation of smooth muscle cells. When present, these lesions predominantly occur in immunocompromised patients in the setting of infection or transplant and have not been known to involve the ventricular system of the brain. In this report, we describe a case of primary leiomyoma of the lateral ventricle in an immunocompetent patient. A 30-year-old man with no medical history presented with progressive diplopia and occipital headaches. Magnetic resonance imaging of the brain revealed a homogenously enhancing mass of the left lateral ventricle with associated cerebral edema. The patient underwent interhemispheric transcallosal craniotomy for resection for symptom alleviation and surgical diagnosis. Histopathology and immunohistochemistry was subsequently consistent with that of leiomyoma. Genetic probing for Epstein-Barr virus was negative. Computed tomography of the chest and abdomen failed to uncover a primary tumor. The patient did well postoperatively and was discharged 3 days after resection. At a two-and-a-half year follow-up, there continued to be no radiologic or clinical evidence of recurrence. To date and to our knowledge, there are fewer than 25 reported cases of primary intracranial leiomyoma, with only 13 occurring in immunocompetent individuals. We believe this is the first report of this tumor type occurring within the ventricular system of the brain. As such, leiomyoma should be considered as a rare etiology in the differential diagnosis of intraventricular lesions. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Intraventricular filling under increasing left ventricular wall stiffness and heart rates

    Science.gov (United States)

    Samaee, Milad; Lai, Hong Kuan; Schovanec, Joseph; Santhanakrishnan, Arvind; Nagueh, Sherif

    2015-11-01

    Heart failure with normal ejection fraction (HFNEF) is a clinical syndrome that is prevalent in over 50% of heart failure patients. HFNEF patients show increased left ventricle (LV) wall stiffness and clinical diagnosis is difficult using ejection fraction (EF) measurements. We hypothesized that filling vortex circulation strength would decrease with increasing LV stiffness irrespective of heart rate (HR). 2D PIV and hemodynamic measurements were acquired on LV physical models of varying wall stiffness under resting and exercise HRs. The LV models were comparatively tested in an in vitro flow circuit consisting of a two-element Windkessel model driven by a piston pump. The stiffer LV models were tested in comparison with the least stiff baseline model without changing pump amplitude, circuit compliance and resistance. Increasing stiffness at resting HR resulted in diminishing cardiac output without lowering EF below 50% as in HFNEF. Increasing HR to 110 bpm in addition to stiffness resulted in lowering EF to less than 50%. The circulation strength of the intraventricular filling vortex diminished with increasing stiffness and HR. The results suggest that filling vortex circulation strength could be potentially used as a surrogate measure of LV stiffness. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

  14. MR Spectroscopy to Distinguish between Supratentorial Intraventricular Subependymoma and Central Neurocytoma.

    Science.gov (United States)

    Ueda, Fumiaki; Aburano, Hiroyuki; Ryu, Yasuji; Yoshie, Yuichi; Nakada, Mitsutoshi; Hayashi, Yutaka; Matsui, Osamu; Gabata, Toshifumi

    2017-07-10

    The purpose of this study was to discriminate supratentorial intraventricular subependymoma (SIS) from central neurocytoma (CNC) using magnetic resonance spectroscopy (MRS). Single-voxel proton MRS using a 1.5T or 3T MR scanner from five SISs, five CNCs, and normal controls were evaluated. They were examined using a point-resolved spectroscopy. Automatically calculated ratios comparing choline (Cho), N-acetylaspartate (NAA), myoinositol (MI), and/or glycine (Gly) to creatine (Cr) were determined. Evaluation of Cr to unsuppressed water (USW) was also performed. Mann-Whitney U test was carried out to test the significance of differences in the metabolite ratios. Detectability of lactate (Lac) and alanine (Ala) was evaluated. Although a statistically significant difference (P CNC, no statistical difference was noted between SIS and control spectra (P = 0.11). Statistically significant differences were observed in NAA/Cr between SIS and CNC (P = 0.04) or control spectra (P CNC and control spectra (P CNC for MI and/or Gly to Cr (P = 0.32). Significant statistical differences were found between SIS and control spectra (P CNC (P CNC (P CNC. The present study showed that MRS can be useful in discriminating SIS from CNC.

  15. Intraventricular Hemorrhage and Post Hemorrhagic Hydrocephalus among Very-Low-Birth-Weight Infants in Korea.

    Science.gov (United States)

    Ahn, So Yoon; Shim, So-Yeon; Sung, In Kyung

    2015-10-01

    Here, we aimed to evaluate the incidence and mortality of intraventricular hemorrhage (IVH) and post-hemorrhagic hydrocephalus (PHH) among very-low-birth-weight (VLBW) infants in Korea and assess the associated factors of PHH. This cohort study used prospectively collected data from the Korean Neonatal Network (KNN). Among 2,386 VLBW infants in the KNN database born between January 2013 and June 2014, 63 infants who died without brain ultrasonography results were excluded. Maternal demographics and neonatal clinical characteristics were assessed. The overall incidence of IVH in all the VLBW infants was 42.2% (987 of 2,323), while those of IVH grade 1, 2, 3, and 4 were 25.1%, 7.0%, 4.8%, and 5.5%, respectively. The incidence and severity of IVH showed a negatively correlating trend with gestational age and birth weight. PHH developed in 0%, 3.5%, 36.1%, and 63.8% of the surviving infants with IVH grades 1, 2, 3, and 4, respectively. Overall, in the VLBW infants, the IVH-associated mortality rate was 1.0% (24/2,323). Only IVH grade severity was proven to be an associated with PHH development in infants with IVH grades 3-4. This is the first Korean national report of IVH and PHH incidences in VLBW infants. Further risk factor analyses or quality improvement studies to reduce IVH are warranted.

  16. Beagle puppy model of intraventricular hemorrhage: effect of indomethacin on cerebral blood flow

    International Nuclear Information System (INIS)

    Ment, L.R.; Stewart, W.B.; Duncan, C.C.; Scott, D.T.; Lambrecht, R.

    1983-01-01

    The newborn beagle puppy has been demonstrated to provide a good model for neonatal intraventricular hemorrhage (IVH). A study was designed to determine if indomethacin can prevent IVH and if indomethacin would produce changes in cerebral blood flow (CBF). Newborn beagle puppies were randomized by computer into two groups: one was pretreated with indomethacin, a known inhibitor of prostaglandin synthetase, and the other was saline. The dogs in both groups were then assigned either to undergo hemorrhagic hypotension/volume reexpansion insult or to receive no insult. Twenty percent of all pups receiving indomethacin and undergoing the insult experienced IVH, compared to 71% of the pups undergoing insult that had been pretreated with saline. Significant alterations in the blood pressure responses to the hemorrhagic hypotension/volume reexpansion insult were noted in the former group compared to the saline-pretreated pups subjected to insult. Finally, employing carbon-14 autoradiography for the determination of CBF, it was demonstrated that indomethacin decreases resting CBF of the newborn beagle pups and, in indomethacin-pretreated animals subjected to insult, prevents the increases in CBF seen in the saline-pretreated traumatized pups. 62 references, 1 figure, 3 tables

  17. A Century of Germinal Matrix Intraventricular Hemorrhage in Autopsied Premature Infants: A Historical Account.

    Science.gov (United States)

    Hefti, Marco M; Trachtenberg, Felicia L; Haynes, Robin L; Hassett, Catherine; Volpe, Joseph J; Kinney, Hannah C

    2016-01-01

    The care of premature infants in the 20th century is remarkable for technical advances that have dramatically improved survival, but little is known about temporal changes in the neuropathology of the premature infant over this time frame. We hypothesize that the autopsy rate of germinal matrix hemorrhage changed in the 20th century relative to combined influences of clinical interventions that were both harmful and helpful. We examined germinal matrix hemorrhage with intraventricular hemorrhage (GMH-IVH) in 345 premature infants (gestational age 25-36 weeks) autopsied at Boston Children's Hospital from 1914 to 2015. There was a median of 19 cases/decade (range 7-68). Over the course of the study median gestational age decreased from 33 to 27 gestational weeks (P3-fold around the time of the introduction of positive pressure ventilation into premature intensive care in the mid-1960s. The increased incidence of GMH-IVH in the 1970s-1980s likely reflects respiratory and hemodynamic imbalances complicating mechanical ventilation. We speculate that the subsequent decreased incidence of GMH-IVH likely reflects stabilization of respiratory function with improvements in ventilators and in ventilator management beginning in the 1970s and the use of surfactant and antenatal steroids in the 1980s.

  18. [Correlation between the use of sodium bicarbonate and intraventricular hemorrhage in preterms].

    Science.gov (United States)

    García-Pasquel, María José; Iglesias-Leboreiro, José; Bernardez-Zapata, Isabel

    2015-01-01

    Being born preterm implies comorbidities, among them the risk of intraventricular hemorrhage (IVH). The use of sodium bicarbonate has been linked to the presence of IVH. The main purpose of this study was to determine if the infusion of sodium bicarbonate during the first 24 hours increases the risk of IVH in preterm infants. Our study is a cohort; we analyzed the files of 160 patients and divided them into two groups: one in which sodium bicarbonate was not used and another in which it was; this latter group was subdivided into two considering if the use was therapeutic of prophylactic. In our total group of patients 10 % presented IVH; had a mean weight of 1500 g and 31 weeks of gestational age. The incidence of IVH was identical between both groups, although patients in which bicarbonate was used were more premature, unstable, and in worse clinical conditions. Our data indicate the need of large scale studies to determine if the clinical benefits of the use of sodium bicarbonate outweigh the risk of IVH.

  19. Postoperative follow-up CT of malignant gliomas. With special reference to intraventricular and subarachnoid dissemination

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Akira; Matsukado, Yasuhiko; Hirata, Yoshifumi; Uemura, Shozaburo

    1986-02-01

    Ten postoperative patients with intraventricular and subarachnoid dissemination of supratentorial gliomas were evaluated with a follow-up CT scan. The tumors consisted of 9 malignant gliomas and 1 astrocytoma. In 5 of the 9 malignant gliomas, the ventricles were surgically opened. In 4 of these 5 patients, a regional linear enhancement of the ventricular wall was observed in the early postoperative period. These findings were the initial findings indicative of tumor dissemination in the CSF space; a postoperative CT follow-up should be done within a few weeks after the operation, especially when the ventricles were ruptured. Subarachnoid dissemination and/or ventricular implantation could also be observed in the follow-up CT of such low-grade gliomas as optic gliomas, and there was no marked difference in the CT findings between low-grade and malignant gliomas. Concomittant progressive ventricular dilatation in early postoperative period was noted in 8 of the 10 patients with serial CT studies. It was considered that hydrocephalus was the another indication for advancing subarachnoid dissemination.

  20. Intraventricular pneumocephalus associated with nasocephalic necrosis in a puppy: a case report

    Directory of Open Access Journals (Sweden)

    J.O. Sena

    Full Text Available ABSTRACT Pneumocephalus is defined as the presence of air in any of the intracranial compartments. Its most frequent causes are trauma and cranial surgery. Clinical signs occur as a result of increased intracranial pressure and vary with the location and extent of the lesion. A case involving a seven-month-old female Saint Bernard, who suffered cranial trauma caused by a bite to the face at ten days of age and had presented with seizures and localized pain four months previously is reported. A computed tomography scan of the skull revealed a nasocephalic mass with low contrast enhancement, bone lysis, and hypodensity (-940 Hounsfield units of the lateral and third ventricles, indicating intraventricular pneumocephalus. During surgery, a fragment of the mass was collected for histopathological examination, which demonstrated the presence of multifocal areas of necrosis. The computed tomography (CT is a reliable method for the characterization of intracranial lesions and diagnosis of pneumocephalus, whose occurrence must be considered in pathological processes in which there is increased intracranial pressure and in patients undergoing certain surgical procedures and anesthetic specific, and CT is indicated as a monitoring tool for these patients.

  1. 3D ultrasound system to investigate intraventricular hemorrhage in preterm neonates

    Science.gov (United States)

    Kishimoto, J.; de Ribaupierre, S.; Lee, D. S. C.; Mehta, R.; St. Lawrence, K.; Fenster, A.

    2013-11-01

    Intraventricular hemorrhage (IVH) is a common disorder among preterm neonates that is routinely diagnosed and monitored by 2D cranial ultrasound (US). The cerebral ventricles of patients with IVH often have a period of ventricular dilation (ventriculomegaly). This initial increase in ventricle size can either spontaneously resolve, which often shows clinically as a period of stabilization in ventricle size and eventual decline back towards a more normal size, or progressive ventricular dilation that does not stabilize and which may require interventional therapy to reduce symptoms relating to increased intracranial pressure. To improve the characterization of ventricle dilation, we developed a 3D US imaging system that can be used with a conventional clinical US scanner to image the ventricular system of preterm neonates at risk of ventriculomegaly. A motorized transducer housing was designed specifically for hand-held use inside an incubator using a transducer commonly used for cranial 2D US scans. This system was validated using geometric phantoms, US/MRI compatible ventricle volume phantoms, and patient images to determine 3D reconstruction accuracy and inter- and intra-observer volume estimation variability. 3D US geometric reconstruction was found to be accurate with an error of 0.05) for the measured ventricle volumes between observers. This 3D US system can reliably produce 3D US images of the neonatal ventricular system. There is the potential to use this system to monitor the progression of ventriculomegaly over time in patients with IVH.

  2. Characterization of neonatal patients with intraventricular hemorrhage using 3D ultrasound cerebral ventricle volumes

    Science.gov (United States)

    Kishimoto, Jessica; Fenster, Aaron; Lee, David S. C.; de Ribaupierre, Sandrine

    2015-03-01

    One of the major non-congenital cause of neurological impairment among neonates born very preterm is intraventricular hemorrhage (IVH) - bleeding within the lateral ventricles. Most IVH patients will have a transient period of ventricle dilation that resolves spontaneously. However, those patients most at risk of long-term impairment are those who have progressive ventricle dilation as this causes macrocephaly, an abnormally enlarged head, then later causes increases intracranial pressure (ICP). 2D ultrasound (US) images through the fontanelles of the patients are serially acquired to monitor the progression of the ventricle dilation. These images are used to determine when interventional therapies such as needle aspiration of the built up CSF might be indicated for a patient. Initial therapies usually begin during the third week of life. Such interventions have been shown to decrease morbidity and mortality in IVH patients; however, this comes with risks of further hemorrhage or infection; therefore only patients requiring it should be treated. Previously we have developed and validated a 3D US system to monitor the progression of ventricle volumes (VV) in IVH patients. This system has been validated using phantoms and a small set of patient images. The aim of this work is to determine the ability of 3D US generated VV to categorize patients into those who will require interventional therapies, and those who will have spontaneous resolution. Patients with higher risks could therefore be monitored better, by re-allocating some of the resources as the low risks infants would need less monitoring.

  3. Quantitative head ultrasound measurements to determine thresholds for preterm neonates requiring interventional therapies following intraventricular hemorrhage

    Science.gov (United States)

    Kishimoto, Jessica; Fenster, Aaron; Salehi, Fateme; Romano, Walter; Lee, David S. C.; de Ribaupierre, Sandrine

    2016-04-01

    Dilation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage (IVH). This post hemorrhagic ventricle dilation (PHVD) can lead to lifelong neurological impairment through ischemic injury due to increased intracranial pressure and without treatment, can lead to death. Clinically, 2D ultrasound (US) through the fontanelles ('soft spots') of the patients are serially acquired to monitor the progression of the ventricle dilation. These images are used to determine when interventional therapies such as needle aspiration of the built up cerebrospinal fluid (CSF) ('ventricle tap', VT) might be indicated for a patient; however, quantitative measurements of the growth of the ventricles are often not performed. There is no consensus on when a neonate with PHVD should have an intervention and often interventions are performed after the potential for brain damage is quite high. Previously we have developed and validated a 3D US system to monitor the progression of ventricle volumes (VV) in IVH patients. We will describe the potential utility of quantitative 2D and 3D US to monitor and manage PHVD in neonates. Specifically, we will look to determine image-based measurement thresholds for patients who will require VT in comparison to patients with PHVD who resolve without intervention. Additionally, since many patients who have an initial VT will require subsequent interventions, we look at the potential for US to determine which PHVD patients will require additional VT after the initial one has been performed.

  4. ETIOPATHOGENIC CHARACTERISTICS OF THE INTRAVENTRICULAR HEMORRHAGES IN THE STRUCTURE OF PERINATAL BRAIN INJURIES: A LITERATURE REVIEW AND THE RESULTS OF OWN RESEARCH

    Directory of Open Access Journals (Sweden)

    B. M. Glukhov

    2017-01-01

    Full Text Available Background. The term «intraventricular hemorrhage of the newborn» was first introduced in the Soviet Union in 1970s. In the first soviet guidelines on pediatric neurology, the intraventricular hemorrhage (IVH was considered as a complication after birth injury induced by a mechanical trauma to the fetal head due to the choroidal vascular plexus. The first large-scale studies devoted to IVH in children were conducted in the USA in the 1970s after the introduction of ultrasound examination of brain, which is the main instrumental method for IVH diagnostics. In 1978, the specialists manage to explore the germinal matrix of the brain in the fetus and newborn, which is believed to be the main source of IVH in premature newborns. This structure was shown to give rise to brain neuroblasts and glia: this is a capillary-rich area that consists of poorly differentiated randomly arranged cells, and has a soft connective-tissue carcass that can cause IVH in this area in newborns. According to a currently accepted approach, risk factors for IVH are divided into 3 pathogenetic groups: antenatal, intranatal and postnatal. Among the antenatal risk factors, the main role belongs to the prenatal infection, especially viral infection. Besides, mother comorbidities (first of all cardiovascular and endocrine diseases and pathological pregnancy (threatened abortion, severe gestosis and placental insufficiency are also considered as important predictors of IVH. The internatal risk factors include placental detachment, precipitate labor, disseminated intravascular coagulation syndrome in mother etc. In this article the authors present a detailed review of currently available data as well as the results of own studies.Objective: to provide an overview of the stages of the IVH investigation, to identify the main features of the IVH etiopathogenesis comparing to other perinatal disorders of the central nervous system, and to assess the consequences of IVH.Materials and

  5. In Premature Newborns Intraventricular Hemorrhage Causes Cerebral Vasospasm and Associated Neurodisability via Heme-Induced Inflammasome-Mediated Interleukin-1 Production and Nitric Oxide Depletion

    Directory of Open Access Journals (Sweden)

    Michael Eisenhut

    2017-08-01

    Full Text Available BackgroundIntraventricular hemorrhage (IVH occurs in 60–70% of neonates weighing 500–750 g and 10–20% of those weighing 1,000–1,500 g. All forms of IVH have been associated with neurocognitive deficits. Both subarachnoid and IVHs have been associated with delayed vasospasm leading to neurological deficits. Pathways linking hemoglobin release from blood clots to vasospasm include heme-induced activation of inflammasomes releasing interleukin-1 (IL-1 that can cause calcium dependent and independent vasospasm. Free hemoglobin is a potent scavenger of nitric oxide (NO. Depletion of NO, a potent endogenous vasodilator, has been associated with features of vasospasm.HypothesisIn premature newborns, IVH causes cerebral vasospasm and associated neurodisability via heme-induced increased inflammasome-mediated IL-1 production and NO depletion.Confirmation of hypothesis and implicationsThis hypothesis could be confirmed in the IVH animal model with visualization of any associated vasospasm by angiography and in newborns with IVH by transcranial Doppler ultrasonography and correlation with cerebrospinal fluid IL-1 and NO metabolite levels. Confirmation of the role of heme in activation of inflammasomes causing IL-1 production and NO binding could be achieved by measuring the effect of heme scavenging interventions on IL-1 levels and levels of NO metabolites. In addition to removal of the accumulated blood of an IVH by drainage, irrigation, and fibrinolytic therapy intrathecal application of vasodilators and heme scavenging agents like haptoglobin and haemopexin and systemic treatment with inhibitors of inflammasomes like telmisartan could be used to prevent and treat cerebral vasospasm, and thus reduce the risk of associated brain injury in premature neonates.

  6. Clinical Assessment of Intraventricular Blood Transport in Patients Undergoing Cardiac Resynchronization Therapy

    Science.gov (United States)

    Rossini, Lorenzo; Martinez-Legazpi, P.; Benito, Y.; Perez Del Villar, C.; Gonzalez-Mansilla, A.; Barrio, A.; Yotti, R.; Kahn, A. M.; Shadden, S. C.; Fernandez-Aviles, F.; Bermejo, J.; Del Alamo, J. C.

    2015-11-01

    In the healthy heart, left ventricular (LV) filling generates flow patterns which have been proposed to optimize blood transport by coupling diastole and systole phases. We present a novel image-based method to assess how flow patterns influence LV blood transport in patients undergoing cardiac resynchronization therapy (CRT). Solving the advection equation with time-varying inflow boundary conditions allows to track the transport of blood entering the LV in the different filling waves, as well as the transport barriers which couple filling and ejection. The velocity fields were obtained using echocardiographic color Doppler velocimetry, which provides two-dimensional time-resolved flow maps in the apical long axis three-chamber view of the LV. We analyze flow transport in a group of patients with CRT devices as well as in healthy volunteers. In the patients under CRT, the device programming was varied to analyze flow transport under different values of the atrioventricular (AV) conduction delay and to model tachycardia. This analysis illustrates how CRT influences the transit of blood inside the LV, contributes to conserving kinetic energy and favors the generation of hemodynamic forces that accelerate blood in the direction of the LV outflow tract.

  7. 12 Years delayed postoperative spinal recurrence of craniopharyngioma. Case report and literature review.

    Science.gov (United States)

    Marchesini, Nicolò; Soda, Christian; Ricci, Umberto Maria; Sedia, Mattia; Sala, Francesco; Pinna, Giampietro

    2017-12-04

    A case of delayed spinal adamantinomatous craniopharyngioma recurrence is presented. A 54-year-old male patient was admitted in our Emergency Department complaining of urinary disorders and leg pains. He underwent surgical removal of intraventricular craniopharyngioma 12 years previously. On MR imaging a well-circumscribed intradural cistyc mass at the T12 level was reavealed. A T11 and T12 laminotomy was performed and total removal of the tumour was achieved. Histology examination showed adamantinous craniopharyngioma. The authors believe that this represents the third case described of spinal craniofaryngioma recurrence and the first involving the dorsal spine.

  8. Leading causes of preterm delivery as risk factors for intraventricular hemorrhage in very preterm infants: results of the EPIPAGE 2 cohort study.

    Science.gov (United States)

    Chevallier, Marie; Debillon, Thierry; Pierrat, Veronique; Delorme, Pierre; Kayem, Gilles; Durox, Mélanie; Goffinet, François; Marret, Stephane; Ancel, Pierre Yves

    2017-05-01

    Intraventricular hemorrhage is a major risk factor for neurodevelopmental disabilities in preterm infants. However, few studies have investigated how pregnancy complications responsible for preterm delivery are related to intraventricular hemorrhage. We sought to investigate the association between the main causes of preterm delivery and intraventricular hemorrhage in very preterm infants born in France during 2011 between 22-31 weeks of gestation. The study included 3495 preterm infants from the national EPIPAGE 2 cohort study who were admitted to neonatal intensive care units and had at least 1 cranial ultrasound assessment. The primary outcome was grade I-IV intraventricular hemorrhage according to the Papile classification. Multinomial logistic regression models were used to study the relationship between risk of intraventricular hemorrhage and the leading causes of preterm delivery: vascular placental diseases, isolated intrauterine growth retardation, placental abruption, preterm labor, and premature rupture of membranes, with or without associated maternal inflammatory syndrome. The overall frequency of grade IV, III, II, and I intraventricular hemorrhage was 3.8% (95% confidence interval, 3.2-4.5), 3.3% (95% confidence interval, 2.7-3.9), 12.1% (95% confidence interval, 11.0-13.3), and 17.0% (95% confidence interval, 15.7-18.4), respectively. After adjustment for gestational age, antenatal magnesium sulfate therapy, level of care in the maternity unit, antenatal corticosteroids, and chest compressions, infants born after placental abruption had a higher risk of grade IV and III intraventricular hemorrhage compared to those born under placental vascular disease conditions, with adjusted odds ratios of 4.3 (95% confidence interval, 1.1-17.0) and 4.4 (95% confidence interval, 1.1-17.6), respectively. Similarly, preterm labor with concurrent inflammatory syndrome was associated with an increased risk of grade IV intraventricular hemorrhage (adjusted odds ratio

  9. Influence of Bleeding Pattern on Ischemic Lesions After Spontaneous Hypertensive Intracerebral Hemorrhage with Intraventricular Hemorrhage.

    Science.gov (United States)

    Rivera-Lara, Lucia; Murthy, Santosh B; Nekoovaght-Tak, Saman; Ali, Hasan; McBee, Nichol; Dlugash, Rachel; Ram, Malathi; Thompson, Richard; Awad, Issam A; Hanley, Daniel F; Ziai, Wendy C

    2018-03-27

    Concomitant acute ischemic lesions are detected in up to a quarter of patients with spontaneous intracerebral hemorrhage (ICH). Influence of bleeding pattern and intraventricular hemorrhage (IVH) on risk of ischemic lesions has not been investigated. Retrospective study of all 500 patients enrolled in the CLEAR III randomized controlled trial of thrombolytic removal of obstructive IVH using external ventricular drainage. The primary outcome measure was radiologically confirmed ischemic lesions, as reported by the Safety Event Committee and confirmed by two neurologists. We assessed predictors of ischemic lesions including analysis of bleeding patterns (ICH, IVH and subarachnoid hemorrhage) on computed tomography scans (CT). Secondary outcomes were blinded assessment of mortality and modified Rankin scale (mRS) at 30 and 180 days. Ischemic lesions occurred in 23 (4.6%) during first 30 days after ICH. Independent risk factors associated with ischemic lesions in logistic regression models adjusted for confounders were higher IVH volume (p = 0.004) and persistent subarachnoid hemorrhage on CT scan (p = 0.03). Patients with initial IVH volume ≥ 15 ml had five times the odds of concomitant ischemic lesions compared to IVH volume < 15 ml. Patients with ischemic lesions had significantly higher odds of death at 1 and 6 months (but not poor outcome; mRS 4-6) compared to patients without concurrent ischemic lesions. Occurrence of ischemic lesions in the acute phase of IVH is not uncommon and is significantly associated with increased early and late mortality. Extra-parenchymal blood (larger IVH and visible subarachnoid hemorrhage) is a strong predictor for development of concomitant ischemic lesions after ICH.

  10. Intrathecal or intraventricular therapy for post-neurosurgical Gram-negative meningitis: matched cohort study.

    Science.gov (United States)

    Shofty, B; Neuberger, A; Naffaa, M E; Binawi, T; Babitch, T; Rappaport, Z H; Zaaroor, M; Sviri, G; Paul, M

    2016-01-01

    Gram-negative post-operative meningitis due to carbapenem-resistant bacteria (CR-GNPOM) is a dire complication of neurosurgical procedures. We performed a nested propensity-matched historical cohort study aimed at examining the possible benefit of intrathecal or intraventricular (IT/IV) antibiotic treatment for CR-GNPOM. We included consecutive adults with GNPOM in two centres between 2005 and 2014. Patients receiving combined systemic and IT/IV treatment were matched to patients receiving systemic treatment only. Matching was done based on the propensity of the patients to receive IT/IV treatment. We compared patient groups with 30-day mortality defined as the primary outcome. The cohort included 95 patients with GNPOM. Of them, 37 received IT/IV therapy in addition to systemic treatment (22 with colistin and 15 with amikacin), mostly as initial therapy, through indwelling cerebrospinal fluid drains. Variables associated with IT/IV therapy in the propensity score included no previous neurosurgery, time from admission to meningitis, presence of a urinary catheter and GNPOM caused by carbapenem-resistant Gram-negative bacteria. Following propensity matching, 23 patients given IT/IV therapy and 27 controls were analysed. Mortality was significantly lower with IT/IV therapy: 2/23 (8.7%) versus 9/27 (33.3%), propensity-adjusted OR 0.19, 95% CI 0.04-0.99. Death or neurological deterioration at 30 days, 14-day and in-hospital mortality were lower with IT/IV therapy (OR <0.4 for all) without statistically significant differences. Among patients discharged alive, those receiving IT/IV therapy did not experience more neurological deterioration. Serious adverse events with IT/IV therapy were not documented. Our results support the early use of IT antibiotic treatment for CR-GNPOM when a delivery method is available. Copyright © 2015 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  11. Use of intraventricular ribbon gauze to reduce particulate emboli during aortic valve replacement

    Directory of Open Access Journals (Sweden)

    Loubani Mahmoud

    2006-11-01

    Full Text Available Abstract Background The incidence of cerebrovascular accidents following aortic valve surgery remains a devastating complication. The aim of this study was to determine the number of potential embolic material arising during aortic valve replacement and to examine the efficacy of using ribbon gauze in the left ventricle during removal of the native valve and decalcification of the aortic annulus. Methods Ribbon gauze was inserted into the left ventricular cavity prior to aortic valve excision in an unselected, prospectively studied series of 30 patients undergoing aortic valve replacement. A further 30 lengths of ribbon gauze were soaked in the pericardiotomy blood of the same patients and all were subjected to histological analysis. Results The median number of tissue fragments from the aortic valve replacement group was significantly higher than in the control group 5 (0–18 versus 0 (0–1 (p = 3.6 × 10-5. The size of tissue fragments varied between 0.1 and 9.0 mm with a mean of 0.61 ± 1.12 mm and a median of 0.2 mm. There was a significantly higher number of tissue fragments associated with patients having surgery for aortic stenosis when compared with patients who had aortic regurgitation with median of 5 (0–18 versus 0 (0–3 (p = 0.8 × 10-3. Conclusion Significant capture of particulate debris by the intraventricular ribbon gauze suggests that the technique of left ventricular ribbon gauze insertion during aortic valve excision has merit.

  12. Therapy of CNS leukemia with intraventricular chemotherapy and low-dose neuraxis radiotherapy

    International Nuclear Information System (INIS)

    Steinherz, P.; Jereb, B.; Galicich, J.

    1985-01-01

    Successful treatment of CNS leukemic relapse has been frustrated by frequent local recurrence and eventual marrow relapse. The authors describe the treatment of meningeal leukemia in 39 children with intrathecal remission induction followed by the placement of an Ommaya reservoir to facilitate the administration and distribution of chemotherapeutic agents into the CSF. Six hundred or 900 rad of craniospinal radiation and maintenance intraventricular and intrathecal chemotherapy was then administered. Systemic reinduction therapy was added in the later cases. Sixteen children (41%) experienced no further events, with 17+ months to 13+ years (median, 25 months) follow-up . Eleven patients (28%) had CNS recurrence, nine (23%) bone marrow (BM) relapse, and two (5%) testicular relapse as the next adverse event. The course of patients with first isolated CNS relapse differed from that of the others. Eleven (69%) of 16 patients treated for first isolated CNS relapse are alive and 9 are event free, while only 35% of patients whose CNS relapse occurred simultaneously or after recurrent disease at other sites are alive (P = .04). Seven of 23 in the later group are event free. The difference is due to the increased incidence of BM relapse in the later group (30% v 6%; P = .04). For patients with first isolated CNS relapse, the life-table median CNS remission duration is 42 months. The projected CNS relapse-free survival and event-free survival 8 to 10 years after CNS relapse are 40% and 32%, respectively. Headache, nausea, and emesis of short duration were frequent during therapy. In three patients, the reservoir had to be removed for infection. No patient suffered neurologic deficit related to the reservoir. The therapy described can reduce the CNS relapse rate with manageable toxicity

  13. Characterization of intraventricular and intracerebral hematomas in non-contrast CT.

    Science.gov (United States)

    Nowinski, Wieslaw L; Gomolka, Ryszard S; Qian, Guoyu; Gupta, Varsha; Ullman, Natalie L; Hanley, Daniel F

    2014-06-01

    Characterization of hematomas is essential in scan reading, manual delineation, and designing automatic segmentation algorithms. Our purpose is to characterize the distribution of intraventricular (IVH) and intracerebral hematomas (ICH) in NCCT scans, study their relationship to gray matter (GM), and to introduce a new tool for quantitative hematoma delineation. We used 289 serial retrospective scans of 51 patients. Hematomas were manually delineated in a two-stage process. Hematoma contours generated in the first stage were quantified and enhanced in the second stage. Delineation was based on new quantitative rules and hematoma profiling, and assisted by a dedicated tool superimposing quantitative information on scans with 3D hematoma display. The tool provides: density maps (40-85HU), contrast maps (8/15HU), mean horizontal/vertical contrasts for hematoma contours, and hematoma contours below a specified mean contrast (8HU). White matter (WM) and GM were segmented automatically. IVH/ICH on serial NCCT is characterized by 59.0HU mean, 60.0HU median, 11.6HU standard deviation, 23.9HU mean contrast, -0.99HU/day slope, and -0.24 skewness (changing over time from negative to positive). Its 0.1(st)-99.9(th) percentile range corresponds to 25-88HU range. WM and GM are highly correlated (R (2)=0.88; phematoma density distributions is at 55.6±5.8HU with the corresponding GM/hematoma percentiles of 88(th)/40(th). Objective characterization of IVH/ICH and stating the rules quantitatively will aid raters to delineate hematomas more robustly and facilitate designing algorithms for automatic hematoma segmentation. Our two-stage process is general and potentially applicable to delineate other pathologies on various modalities more robustly and quantitatively.

  14. Intraventricular hemorrhage risk factors in very low birth weight newborns: a case-control study

    Directory of Open Access Journals (Sweden)

    Laura Martins

    2009-09-01

    Full Text Available Objective: Identification of variables that affect the risk of severe intraventricular hemorrhage (IVH in very low birth weight (VLBW newborns. Methods: Analytic case-control study, in a population consisting of all VLBW newborns admitted to the Neonatal Intensive Care Unit of a maternity hospital, between January 2002 and December 2007. The authors considered as cases all VLBW newborns with severe IVH (grade ≥ 3, and control all VLBW newborns without IVH. Independent variables included obstetric, perinatal and neonatal diagnosis and therapy. Bivariate analysis and multivariate logistic regression analysis were performed. Rresults: During this period, of the 864 VLBW newborns admitted to the Neonatal Intensive Care Unit, 9.7% had severe IVH. With bivariate analysis an association between severe IVH, gestational age and birth weight was found. Prenatal care and pre-eclampsia were associated with a decrease in the incidence of severe IVH. Amnionitis, being outborn, vaginal delivery, male gender, intubation in the delivery room, surfactant, hyaline membrane disease, pneumothorax, necrotizing enterocolitis (NEC perforation and oscillatory high frequency ventilation were associated with an increased incidence of severe IVH. By multivariate logistic regression, the variables associated with increased risk of severe IVH were: pneumothorax (OR = 3.8; 95%CI = 1.7-8.3, NEC with perforation (OR = 8.8; 95%CI = 1.7-45.0, vaginal delivery (OR = 2.0; 95%CI = 1.0-4.1 and high frequency ventilation (OR = 4.8; 95%CI = 1.3-17.3. The following were protective of severe IVH: gestational age (OR = 0.61; 95%CI = 0.52-0.72, patent ductus arteriosus treatment with indomethacin (OR = 0.26; 95%CI = 0.11-0.6 and fertility treatment (OR = 0.24; 95%CI = 0.06-0.94. Cconclusion: These data outline the importance of improvement of pre and neonatal care to reduce severe IVH.

  15. Intraventricular hemorrhage in the preterm neonate: timing and cerebral blood flow changes

    International Nuclear Information System (INIS)

    Ment, L.R.; Duncan, C.C.; Ehrenkranz, R.A.; Lange, R.C.; Taylor, K.J.; Kleinman, C.S.; Scott, D.T.; Sivo, J.; Gettner, P.

    1984-01-01

    Serial cranial ultrasound studies, 133xenon inhalation cerebral blood flow determinations, and risk factor analyses were performed in 31 preterm neonates. Contrast echocardiographic studies were additionally performed in 16 of these 31 infants. Sixty-one percent were found to have germinal matrix or intraventricular hemorrhage. Seventy-four percent of all hemorrhages were detected by the thirtieth postnatal hour. The patients were divided into three groups: early GMH/IVH by the sixth postnatal hour (eight infants) interval GMH/IVH from 6 hours through 5 days (10), and no GMH/IVH (12). Cerebral blood flow values at 6 postnatal hours were significantly lower for the early GMH/IVH group than for the no GMH/IVH group (P less than 0.01). Progression of GMH/IVH was observed only in those infants with early hemorrhage, and these infants had a significantly higher incidence of neonatal mortality. Ventriculomegaly as determined by ultrasound studies was noted equally in infants with and without GMH/IVH (50%) and was not found to correlate with low cerebral blood flow. The patients with early hemorrhage were distinguishable by their need for more vigorous resuscitation at the time of birth and significantly higher ventilator settings during the first 36 postnatal hours, during which time they also had higher values of PCO2. An equal incidence of patent ductus arteriosus was found across all of the groups. We propose that early GMH/IVH may be related to perinatal events and that the significant decrease in cerebral blood flow found in infants with early GMH/IVH is secondary to the presence of the hemorrhage itself. Progression of early GMH/IVH and new interval GMH/IVH may be related to later neonatal events known to alter cerebral blood flow

  16. 3D ultrasound system to investigate intraventricular hemorrhage in preterm neonates

    International Nuclear Information System (INIS)

    Kishimoto, J; Lawrence, K St; De Ribaupierre, S; Fenster, A; Lee, D S C; Mehta, R

    2013-01-01

    Intraventricular hemorrhage (IVH) is a common disorder among preterm neonates that is routinely diagnosed and monitored by 2D cranial ultrasound (US). The cerebral ventricles of patients with IVH often have a period of ventricular dilation (ventriculomegaly). This initial increase in ventricle size can either spontaneously resolve, which often shows clinically as a period of stabilization in ventricle size and eventual decline back towards a more normal size, or progressive ventricular dilation that does not stabilize and which may require interventional therapy to reduce symptoms relating to increased intracranial pressure. To improve the characterization of ventricle dilation, we developed a 3D US imaging system that can be used with a conventional clinical US scanner to image the ventricular system of preterm neonates at risk of ventriculomegaly. A motorized transducer housing was designed specifically for hand-held use inside an incubator using a transducer commonly used for cranial 2D US scans. This system was validated using geometric phantoms, US/MRI compatible ventricle volume phantoms, and patient images to determine 3D reconstruction accuracy and inter- and intra-observer volume estimation variability. 3D US geometric reconstruction was found to be accurate with an error of 3 for a single observer. Results from ANOVA for three observers segmenting three patients of IVH grade II did not show any significant differences (p > 0.05) for the measured ventricle volumes between observers. This 3D US system can reliably produce 3D US images of the neonatal ventricular system. There is the potential to use this system to monitor the progression of ventriculomegaly over time in patients with IVH. (paper)

  17. Porcine pilot study of MRI-guided HIFU treatment for neonatal intraventricular hemorrhage (IVH)

    Science.gov (United States)

    Looi, Thomas; Waspe, Adam; Mougenot, Charles; Amaral, Joao; Temple, Michael; Hynynen, Kullervo; Drake, James

    2012-11-01

    Intraventricular hemorrhage (IVH) occurs in 15% of premature babies and 50% of IVH cases progress to posthemorrhagic ventricular dilation due to large blood clots forming in the ventricles. Existing treatments such as tissue plasminogen activator (tPA) and surgical intervention have severe side effects in paediatric patients that include excessive bleeding and complications. This study investigates the feasibility of MR-HIFU for sonothrombolysis of blood clots from IVH using natural acoustic windows, known as fontanelles, in the skulls of newborns. The study involved 2 elements: a phantom study to examine beam limitations and acoustic properties, and an in-vivo porcine study. A phantom skull was created from sample patient data and was used to analyze reachability of the Philips Sonavelle system. Acoustic measurements of the phantom (attenuation of 5-14 dB and speed of sound of 1722-2965 m/s) indicated the phantom effectively mimics neonatal skull bone. For the ex-vivo studies, a porcine clot was created and sonicated for 5 mins at 500W with a 0.5% duty cycle. For the in-vivo experiment, a vertex craniotomy was performed and porcine blood was injected into the lateral ventricle under ultrasound guidance. Sonication using the prior parameters induced cavitation and post-sonication T1 and T2 images verified clot lysis. Further H&E analysis showed no presence of blood in the ventricles. These positive results show that MR-HIFU has potential as a noninvasive tool for sonothrombolysis of neonatal IVH clots.

  18. Long-term animal experiments with an intraventricular axial flow blood pump.

    Science.gov (United States)

    Yamazaki, K; Kormos, R L; Litwak, P; Tagusari, O; Mori, T; Antaki, J F; Kameneva, M; Watach, M; Gordon, L; Mukuo, H; Umezu, M; Tomioka, J; Outa, E; Griffith, B P; Koyanagai, H

    1997-01-01

    A miniature intraventricular axial flow blood pump (IVAP) is undergoing in vivo evaluation in calves. The IVAP system consists of a miniature (phi 13.9 mm) axial flow pump that resides within the left ventricular (LV) chamber and a brushless DC motor. The pump is fabricated from titanium alloy, and the pump weight is 170 g. It produces a flow rate of over 5 L/min against 100 mmHg pressure at 9,000 rpm with an 8 W total power consumption. The maximum total efficiency exceeds 17%. A purged lip seal system is used in prototype no. 8, and a newly developed "Cool-Seal" (a low temperature mechanical seal) is used in prototype no. 9. In the Cool-Seal system, a large amount of purge flow is introduced behind the seal faces to augment convective heat transfer, keeping the seal face temperature at a low level for prevention of heat denaturation of blood proteins. The Cool-Seal system consumes < 10 cc purge fluid per day and has greatly extended seal life. The pumps were implanted in three calves (26, 30, and 168 days of support). The pump was inserted through a left thoracotomy at the fifth intercostal space. Two pursestring sutures were placed on the LV apex, and the apex was cored with a myocardial punch. The pump was inserted into the LV with the outlet cannula smoothly passing through the aortic valve without any difficulty. Only 5 min elapsed between the time of chest opening and initiation of pumping. Pump function remained stable throughout in all experiments. No cardiac arrhythmias were detected, even at treadmill exercise tests. The plasma free hemoglobin level remained in the acceptable range. Post mortem examination did not reveal any interference between the pump and the mitral apparatus. No major thromboembolism was detected in the vital organs in Cases 1 or 2, but a few small renal infarcts were detected in Case 3.

  19. Clinical features and prognostic factors in patients with intraventricular hemorrhage caused by ruptured arteriovenous malformations

    Science.gov (United States)

    Ye, Zengpanpan; Ai, Xiaolin; Hu, Xin; Fang, Fang; You, Chao

    2017-01-01

    Abstract Intraventricular hemorrhage (IVH) was associated with poor outcomes in patients with intracerebral hemorrhage. IVH had a high incidence in patients with ruptured arteriovenous malformations (AVMs). In this study, we aimed to discuss the clinical features and prognostic factors of outcomes in the patients with AVM-related IVH. From January 2010 to January 2016, we collected the data of the patients with AVM-related IVH retrospectively. The data, including clinical and radiological parameters, were collected to evaluate the clinical features. Univariate and multivariate logistic regression analyses were used to identify the prognostic factors for clinical outcomes (hydrocephalus, 6-month outcomes measured by the modified Rankin scale) in our cohort. A total of 67 eligible patients were included and 19 patients (28%) only presented with IVH. Thirty-three patients (49%) presented hydrocephalus, and 12 patients (18%) presented brain ischemia. Nineteen patients (28%) had a poor outcome after 6 months. In multivariate logistic regression, subarachnoid hemorrhage (SAH) (P = .028) was associated with hydrocephalus and higher Graeb score (P = .080) tended to increase the risk of hydrocephalus. The high Glasgow coma scale (P = .010), large hematoma volume of parenchyma (P = .006), and high supplemented Spetzler–Martin (sup-SM) score (P = .041) were independent factors of the poor outcome. IVH was common in ruptured AVMs and increased the poor outcomes in patients with the ruptured AVMs. The AVM-related IVH patients had a high incidence of hydrocephalus, which was associated with brain ischemia and SAH. Patients with lower Glasgow coma scale, lower sup-SM score, and smaller parenchymal hematoma had better long-term outcomes. PMID:29137064

  20. Two-dimensional intraventricular flow mapping by digital processing conventional color-Doppler echocardiography images.

    Science.gov (United States)

    Garcia, Damien; Del Alamo, Juan C; Tanne, David; Yotti, Raquel; Cortina, Cristina; Bertrand, Eric; Antoranz, José Carlos; Perez-David, Esther; Rieu, Régis; Fernandez-Aviles, Francisco; Bermejo, Javier

    2010-10-01

    Doppler echocardiography remains the most extended clinical modality for the evaluation of left ventricular (LV) function. Current Doppler ultrasound methods, however, are limited to the representation of a single flow velocity component. We thus developed a novel technique to construct 2D time-resolved (2D+t) LV velocity fields from conventional transthoracic clinical acquisitions. Combining color-Doppler velocities with LV wall positions, the cross-beam blood velocities were calculated using the continuity equation under a planar flow assumption. To validate the algorithm, 2D Doppler flow mapping and laser particle image velocimetry (PIV) measurements were carried out in an atrio-ventricular duplicator. Phase-contrast magnetic resonance (MR) acquisitions were used to measure in vivo the error due to the 2D flow assumption and to potential scan-plane misalignment. Finally, the applicability of the Doppler technique was tested in the clinical setting. In vitro experiments demonstrated that the new method yields an accurate quantitative description of the main vortex that forms during the cardiac cycle (mean error for vortex radius, position and circulation). MR image analysis evidenced that the error due to the planar flow assumption is close to 15% and does not preclude the characterization of major vortex properties neither in the normal nor in the dilated LV. These results are yet to be confirmed by a head-to-head clinical validation study. Clinical Doppler studies showed that the method is readily applicable and that a single large anterograde vortex develops in the healthy ventricle while supplementary retrograde swirling structures may appear in the diseased heart. The proposed echocardiographic method based on the continuity equation is fast, clinically-compliant and does not require complex training. This technique will potentially enable investigators to study of additional quantitative aspects of intraventricular flow dynamics in the clinical setting by

  1. Intraventricular hemorrhage in a very low birth weight infants: Associated risk factors in Isfahan, Iran

    International Nuclear Information System (INIS)

    Badiee, Z.

    2007-01-01

    Prematurely born infants with intraventricular hemorrhage (IVH) suffer significant morbidity and mortality, particularly with those infants with high-grade hemorrhage. Previous studies have proposed a number of risk factors for IVH; however, lack of adequate matching for gestational age and birth weight may have confounded the results. The purpose of this study was to identify variables that affect the risk of IVH. We identified 31 preterm infants with gestational age < 32 weeks and birth weight < 1500 g, with IVH, from November 2003 to January 2005 at Alzahra University Hospital, Isfahan, Iran. A control group of 90 infants, matched for gestational age and birth weight was selected. Maternal factors, labor and delivery characteristics and neonatal parameters were collected in both groups. Results of cranial ultrasound examinations were also collected. The significant risk factors for IVH were found to be: patent ductus artreiosus arteriosus (PDA) [4 (13.3%) versus 3(3.3%) (p=0.01)], longer duration of assisted ventilation [4 (2.8+-5.8 days versus 0.5+-2.1 days (p=0.002)], a higher number of endotracheal suctioning [9.7+-18.4 versus 3.06+-13.7 (p=0.004)], surfactant use, [7(22.6%) versus 3(3.4%) (p=0.003)], positive pressure ventilation at birth [12 (38.7%) versus 12(13.3%), (p=0.004)] and low Apgar score at 1 and 5 minutes. Whereas antenatal steroid treatments and cesarean sections have protective effect on the occurrence of IVH. Our data emphasize the importance of obstetric and prenatal care to improve outcomes of premature infants. (author)

  2. Infective Endocarditis Complicated by Intraventricular Abscesses, Pericarditis, and Mycotic Aneurysm Due to an Emerging Strain of Serotype VI Streptococcus agalactiae.

    Science.gov (United States)

    Hirai, Nobuyasu; Kasahara, Kei; Uno, Kenji; Ogawa, Yoshihiko; Ogawa, Taku; Yonekawa, Shinsuke; Nakano, Ryuichi; Yano, Hisakazu; Sakagami, Azusa; Uemura, Takayuki; Okura, Hiroyuki; Saito, Yoshihiko; Yoshikawa, Masahide; Mikasa, Keiichi

    2017-11-22

    An increasing number of invasive infections due to Streptococcus agalactiae in non-pregnant adults have been reported. We report a case of infective endocarditis complicated by intraventricular abscesses, pericarditis, and mycotic aneurysm due to S. agalactiae belonging to ST681 with a capsular serotype VI in a woman with diabetes. The patient also had a myocardial infarction and was treated with percutaneous coronary intervention, pericardiocentesis, and 6 weeks of antibiotic treatment. Invasive infections due to serotype VI S. agalactiae are common in Asian countries such as Taiwan and Japan, so continuous monitoring of invasive S. agalactiae strains is warranted.

  3. Delayed Senescence

    Science.gov (United States)

    2004-01-01

    Researcher Dr. Yi Li developed a technique to manipulate certain characteristics of plant growth such as anit-senescence. For example, the tobacco leaf was clipped from a transgenic plant (right), and a wildtype plant (left). During ground-based laboratory studies, both leaves were left in a darkened area for 4 months. When retrieved, the wildtype plant leaf was dried-out and the transgenic leaf remained fresh and green. A variation of this technology that involves manipulating plant hormones has been conducted in space-based studies on tomato plants through BioServe Space Technologies. The transport and distribution of auxin, an important plant hormone has shown to be influenced by microgravity, which could lead to improving the quality of fruits and vegetables grown on Earth.

  4. Delayed puberty in girls

    Science.gov (United States)

    ... sexual development - girls; Pubertal delay - girls; Constitutional delayed puberty ... In most cases of delayed puberty, growth changes just begin later than usual, sometimes called a late bloomer. Once puberty begins, it progresses normally. This pattern runs ...

  5. Delayed Puberty (For Teens)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Delayed Puberty KidsHealth / For Teens / Delayed Puberty What's in this ... wonder if there's anything wrong. What Is Delayed Puberty? Puberty is the time when your body grows ...

  6. Effects of AV delay programming on ventricular resynchronisation: role of radionuclide ventriculography

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, Patrick T.; Comte, Nathalie; Holzmeister, Johannes; Suetsch, Gabor; Koepfli, Pascal; Namdar, Mehdi; Duru, Firat; Brunckhorst, Corinna; Scharf, Christoph [Universitiy Hospital Zurich NUK C 32, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [Universitiy Hospital Zurich NUK C 32, Cardiovascular Center, Zurich (Switzerland); University of Zurich, Zurich Center for Integrative Human Physiology, Zurich (Switzerland)

    2008-08-15

    Optimal atrioventricular delay (AVD) setting for cardiac resynchronisation therapy, i.e. biventricular pacing in patients with heart failure, remains a formidable challenge. Thus, the purpose of this study was to evaluate the effects of different AVD on inter- and intra-ventricular resynchronisation using phase histograms of radionuclide ventriculography (RNV). In 17 consecutive patients (mean age 64 {+-} 6 years), RNV was performed 236 {+-} 350 days after pacemaker implantation for cardiac resynchronisation therapy. Images were acquired during atrial pacing at 80 bpm and during biventricular pacing with AVD ranging from 80 to 160 ms. Inter-ventricular dyssynchrony was measured by the delay between the mean phase angles of the left and right ventricles. Intra-ventricular dyssynchrony was measured by the standard deviation (SD) of left ventricular phase histograms. Left ventricular (LV) ejection fraction (EF) was inversely correlated to LV dyssynchrony (SD of LV phase histogram, R = -0.82, p < 0.0001). However, the increase in LVEF by biventricular pacing (mean +4.4 {+-} 4%) showed only modest correlation to the resulting resynchronisation effect (characterised by a -13 {+-} 8 decrease in LV phase histogram SD, R = -0.38, p < 0.0001). RNV is helpful in optimising pacing parameters for resynchronisation therapy. Varying AVD did not have a major impact on intra- or inter-ventricular resynchronisation. Thus, the benefit of AVD-based LVEF optimisation seems to result from atrioventricular resynchronisation. (orig.)

  7. Echocardiographic estimation of acute haemodynamic response during optimization of multisite pace-maker using different pacing modalities and atrioventricular delays

    Directory of Open Access Journals (Sweden)

    Šalinger-Martinović Sonja

    2009-01-01

    Full Text Available Background/Aim. Cardiac resynchronization therapy (CRT improves ventricular dyssynchrony and is associated with an improvement in symptoms, quality of life and prognosis in patients with severe heart failure and intraventricular conduction delay. Different pacing modalities produce variable activation patterns and may be a cause of different haemodynamic changes. The aim of our study was to investigate acute haemodynamic changes with different CRT configurations during optimization procedure. Methods. This study included 30 patients with severe left ventricular systolic dysfunction and left bundle branch block with wide QRS (EF 24.33 ± 3.7%, QRS 159 ± 17.3 ms, New York Heart Association III/IV 25/5 with implanted CRT device. The whole group of patients had severe mitral regurgitation in order to measure dP/dt. After implantation and before discharge all the patients underwent optimization procedure guided by Doppler echocardiography. Left and right ventricular pre-ejection intervals (LVPEI and RVPEI, interventricular mechanical delay (IVD and the maximal rate of ventricular pressure rise during early systole (max dP/dt were measured during left and biventricular pacing with three different atrioventricular (AV delays. Results. After CRT device optimization, optimal AV delay and CRT mode were defined. Left ventricular pre-ejection intervals changed from 170.5 ± 24.6 to 145.9 ± 9.5 (p < 0.001, RVPEI from 102.4 ± 15.9 to 119.8 ± 10.9 (p < 0.001, IVD from 68.1 ± 18.3 to 26.5 ± 8.2 (p < 0.001 and dP/dt from 524.2 ± 67 to 678.2 ± 88.5 (p < 0.01. Conclusion. In patients receiving CRT echocardiographic assessment of the acute haemodynamic response to CRT is a useful tool in optimization procedure. The variability of Doppler parameters with different CRT modalities emphasizes the necessity of individualized approach in optimization procedure.

  8. Intraventricular Transplantation of Autologous Bone Marrow Mesenchymal Stem Cells via Ommaya Reservoir in Persistent Vegetative State Patients after Haemorrhagic Stroke: Report of Two Cases & Review of the Literature

    Directory of Open Access Journals (Sweden)

    Fauzi AA

    2016-11-01

    Full Text Available Background: One of the most devastating diseases, stroke, is a leading cause of death and disability worldwide with severe emotional and economic consequences. The purpose of this article is mainly to report the effect of intraventricular transplantation via an Ommaya reservoir using autologous bone marrow mesenchymal stem cells (BM-MSCs in haemorrhagic stroke patients. Case Presentations: Two patients, aged 51 and 52, bearing sequels of haemorrhagic stroke were managed by intraventricular transplantation of BM-MSCs obtained from their own bone marrow. Before the procedure, both patients were bedridden, tracheostomised, on nasogastric (NG tube feeding and in hemiparesis. The cells were transplanted intraventricularly (20 x 106 cells/2.5 ml using an Ommaya reservoir, and then repeated transplantations were done after 1 and 2 months consecutively. The safety and efficacy of the procedures were evaluated 3, 6 and 12 months after treatment. The National Institute of Health Stroke Scale (NIHSS was used to evaluate the patients' neurological status before and after treatment. No adverse events derived from the procedures or transplants were observed in the one-year follow-up period, and the neurological status of both patients improved after treatment. Conclusions: Our report demonstrates that the intraventricular transplantation of BM-MSCs via an Ommaya reservoir is safe and it improves the neurological status of post-haemorrhagic stroke patients. The repeated transplantation procedure is easier and safer to perform via a subcutaneously implanted Ommaya reservoir.

  9. Effects of Probiotics on Necrotizing Enterocolitis, Sepsis, Intraventricular Hemorrhage, Mortality, Length of Hospital Stay, and Weight Gain in Very Preterm Infants: A Meta-Analysis.

    Science.gov (United States)

    Sun, Jing; Marwah, Gayatri; Westgarth, Matthew; Buys, Nicholas; Ellwood, David; Gray, Peter H

    2017-09-01

    Probiotics are increasingly used as a supplement to prevent adverse health outcomes in preterm infants. We conducted a systematic review, meta-analysis, and subgroup analysis of findings from randomized controlled trials (RCTs) to assess the magnitude of the effect of the probiotics on health outcomes among very-low-birth-weight (VLBW) infants. Relevant articles from January 2003 to June 2017 were selected from a broad range of databases, including Medline, PubMed, Scopus, and Embase. Studies were included if they used an RCT design, involved a VLBW infant (birthweight probiotic intervention group, measured necrotizing enterocolitis (NEC) as a primary outcome, and measured sepsis, mortality, length of hospital stay, weight gain, and intraventricular hemorrhage (IVH) as additional outcomes. The initial database search yielded 132 potentially relevant articles and 32 ( n = 8998 infants) RCTs were included in the final meta-analysis. Subgroup analysis was used to evaluate the effects of the moderators on the outcome variables. In the probiotics group, it was found that NEC was reduced by 37% (95% CI: 0.51%, 0.78%), sepsis by 37% (95% CI: 0.72%, 0.97%), mortality by 20% (95% CI: 0.67%, 0.95%), and length of hospital stay by 3.77 d (95% CI: -5.94, -1.60 d). These findings were all significant when compared with the control group. There was inconsistent use of strain types among some of the studies. The results indicate that probiotic consumption can significantly reduce the risk of developing medical complications associated with NEC and sepsis, reduce mortality and length of hospital stay, and promote weight gain in VLBW infants. Probiotics are more effective when taken in breast milk and formula form, consumed for Probiotics are not effective in reducing the incidence of IVH in VLBW infants. © 2017 American Society for Nutrition.

  10. [Impact of screening and treatment of low systemic blood flow in the prevention of severe intraventricular haemorrhage and/or death in pre-term infants].

    Science.gov (United States)

    Oulego Erroz, Ignacio; Alonso Quintela, Paula; Jiménez Gonzalez, Aquilina; Terroba Seara, Sandra; Rodríguez Blanco, Silvia; Rosón Varas, María; Castañón López, Leticia

    2018-04-02

    To assess the effect of a protocolised intervention for low systemic blood flow (SBF) in the occurrence of severe intraventricular haemorrhage (IVH) or death in pre-term infants. A study with a quasi-experimental design with retrospective controls was conducted on pre-term infants of less than 30weeks of gestational age, born between January 2016 and July 2017, who were consecutively included in the intervention period. The control cohort included pre-term infants (born between January 2013 and December 2015) matched by gestational age, birth weight, and gender (two controls for each case). The cases of low SBF diagnosed according to functional echocardiography during the study period received dobutamine (5-10μg/kg/min) for 48hours. The study included 29 cases (intervention period) and 54 controls (pre-intervention period). Ten out of 29 (34.5%) infants received dobutamine for low SBF during the intervention period, with 3/29 (10.3%) cases of severe IVH and/or death compared to 17/54 (31.5%) in the control cohort (p=.032). There was an independent association between the intervention and a decreased occurrence of severe IVH/death after adjusting for confounding factors both in the logistic regression model [OR 0.11 (95%CI: 0.01-0.65), p=.015], as well as in the sensitivity analysis using inverse probability of treatment weighting [OR 0.23 (95%CI: 0.09-0.56); p=.001]. In this study with retrospective controls, a protocolised screening, and treatment for low SBF was associated with a decreased occurrence of severe IVH or death in preterm infants. Large, adequately powered trials, are needed in order to determine whether postnatal interventions directed at low SBF can improve neurological outcomes. Copyright © 2018. Publicado por Elsevier España, S.L.U.

  11. Postnatal phenobarbital for the prevention of intraventricular haemorrhage in preterm infants.

    Science.gov (United States)

    Smit, Elisa; Odd, David; Whitelaw, Andrew

    2013-08-13

    Intraventricular haemorrhage (IVH) is a major complication of preterm birth. Large haemorrhages are associated with a high risk of disability and hydrocephalus. Instability of blood pressure and cerebral blood flow are postulated as causative factors. Another mechanism may involve reperfusion damage from oxygen free radicals. Phenobarbital has been suggested as a safe treatment that stabilises blood pressure and may protect against free radicals. To determine the effect of postnatal administration of phenobarbital on the risk of IVH, neurodevelopmental impairment or death in preterm infants. We used the search strategy of the Neonatal Collaborative Review Group. The original review author (A Whitelaw) was an active trialist in this area and had personal contact with many groups in this field. He handsearched journals from 1976 (when cranial computed tomography (CT) scanning started) to October 2000; these included: Pediatrics, Journal of Pediatrics, Archives of Disease in Childhood, Pediatric Research, Developmental Medicine and Child Neurology, Acta Paediatrica, European Journal of Pediatrics, Neuropediatrics, New England Journal of Medicine, Lancet and British Medical Journal. We searched the National Library of Medicine (USA) database (via PubMed) and the Cochrane Central Register of Controlled Trials (CENTRAL, 2012, Issue 10) through to 31 October 2012. We did not limit the searches to the English language, as long as the article included an English abstract. We read identified articles in the original language or translated. We included randomised or quasi-randomised controlled trials in which phenobarbital was given to preterm infants identified as being at risk of IVH because of gestational age below 34 weeks, birthweight below 1500 g or respiratory failure. Adequate determination of IVH by ultrasound or CT was also required. In addition to details of patient selection and control of bias, we extracted the details of the administration of phenobarbital. We

  12. Speech and Language Delay

    Science.gov (United States)

    ... OTC Relief for Diarrhea Home Diseases and Conditions Speech and Language Delay Condition Speech and Language Delay Share Print Table of Contents1. ... Treatment6. Everyday Life7. Questions8. Resources What is a speech and language delay? A speech and language delay ...

  13. Neurological evaluation of neonates with intraventricular and periventricular hemorrhage Avaliação neurológica de recém-nascidos com hemorragia intraventricular e periventricular

    Directory of Open Access Journals (Sweden)

    MONICA SANCHEZ-STOPIGLIA

    1999-06-01

    Full Text Available We studied the clinical aspects of 100 consecutive premature newborns with and without intraventricular and periventricular hemorrhage (IPVH.The diagnosis of IPVH was obtained by ultrasonic scans of the skull during the first week of life and at the age of one month. Forty eight percent of newborns with IPVH had abnormal results, and there was a significant correlation with the neurological evaluation in 85% of the infants. The probability of normality for a child with no associated brain abnormalities was 72%, whereas for a child of the same gestational age with associated brain abnormalities was 48.7%.Foram estudados os aspectos clínicos de 100 recém-nascidos prematuros, com e sem hemorragia periventricular-intraventricular (HPIV. O diagnóstico foi obtido através de exames ultra-sonográficos de crânio, realizados durante a primeira semana de vida e na idade corrigida de um mês.Quarenta e oito por cento dos recém-nascidos com HPVI evidenciaram resultados anormais, sendo a correlação significativa com a evolução neurológica, em 85% das crianças. Crianças que não apresentaram anormalidades cerebrais associadas tiveram 72% de probabilidade de manter a evolução normal, enquanto para crianças da mesma idade gestacional porém com anormalidades cerebrais associadas, a probabilidade foi 48,7%.

  14. An evaluation and comparison of intraventricular, intraparenchymal, and fluid-coupled techniques for intracranial pressure monitoring in patients with severe traumatic brain injury.

    Science.gov (United States)

    Vender, John; Waller, Jennifer; Dhandapani, Krishnan; McDonnell, Dennis

    2011-08-01

    Intracranial pressure measurements have become one of the mainstays of traumatic brain injury management. Various technologies exist to monitor intracranial pressure from a variety of locations. Transducers are usually placed to assess pressure in the brain parenchyma and the intra-ventricular fluid, which are the two most widely accepted compartmental monitoring sites. The individual reliability and inter-reliability of these devices with and without cerebrospinal fluid diversion is not clear. The predictive capability of monitors in both of these sites to local, regional, and global changes also needs further clarification. The technique of monitoring intraventricular pressure with a fluid-coupled transducer system is also reviewed. There has been little investigation into the relationship among pressure measurements obtained from these two sources using these three techniques. Eleven consecutive patients with severe, closed traumatic brain injury not requiring intracranial mass lesion evacuation were admitted into this prospective study. Each patient underwent placement of a parenchymal and intraventricular pressure monitor. The ventricular catheter tubing was also connected to a sensor for fluid-coupled measurement. Pressure from all three sources was measured hourly with and without ventricular drainage. Statistically significant correlation within each monitoring site was seen. No monitoring location was more predictive of global pressure changes or more responsive to pressure changes related to patient stimulation. However, the intraventricular pressure measurements were not reliable in the presence of cerebrospinal fluid drainage whereas the parenchymal measurements remained unaffected. Intraparenchymal pressure monitoring provides equivalent, statistically similar pressure measurements when compared to intraventricular monitors in all care and clinical settings. This is particularly valuable when uninterrupted cerebrospinal fluid drainage is desirable.

  15. A case of pneumothorax following bougie-guided intubation in a patient undergoing excision of an intraventricular space occupying lesion

    Directory of Open Access Journals (Sweden)

    Ramanan Rajagopal

    2017-01-01

    Full Text Available A 46-year-old female with intraventricular space occupying lesion was posted for craniotomy and excision of the same. Immediately following routine induction of general anaesthesia and a bougie-guided intubation, she developed increased airway pressures and desaturation associated with a decreased air entry on the right side of the chest suggestive of a right-sided pneumothorax which was confirmed with radio imaging and following the placement of chest drain the saturation improved and airway pressures decreased. To be faced with a pneumothorax following an intubation could be surprising for a non-suspecting anaesthesiologist and it can have important implications especially in neurosurgical cases where a tight control of intracranial pressure is warranted. Hence, this case report emphasises the need for a high index of clinical suspicion for proper management and safe patient outcome.

  16. Acute alcohol intoxication, diffuse axonal injury and intraventricular bleeding in patients with isolated blunt traumatic brain injury.

    Science.gov (United States)

    Matsukawa, Hidetoshi; Shinoda, Masaki; Fujii, Motoharu; Takahashi, Osamu; Murakata, Atsushi; Yamamoto, Daisuke

    2013-01-01

    The influence of blood alcohol level (BAL) on outcome remains unclear. This study investigated the relationships between BAL, type and number of diffuse axonal injury (DAI), intraventricular bleeding (IVB) and 6-month outcome. This study reviewed 419 patients with isolated blunt traumatic brain injury. First, it compared clinical and radiological characteristics between patients with good recovery and disability. Second, it compared BAL among DAI lesions. Third, it evaluated the correlation between the BAL and severity of IVB, number of DAI and corpus callosum injury lesions. Regardless of BAL, older age, male gender, severe Glasgow Coma Scale score (injury lesions. Acute alcohol intoxication was not associated with type and number of DAI lesion, IVB and disability. This study suggested that a specific type of traumatic lesion, specifically lesion on genu of corpus callosum and IVB, might be more vital for outcome.

  17. A risk prediction model for severe intraventricular hemorrhage in very low birth weight infants and the effect of prophylactic indomethacin.

    Science.gov (United States)

    Luque, M J; Tapia, J L; Villarroel, L; Marshall, G; Musante, G; Carlo, W; Kattan, J

    2014-01-01

    Develop a risk prediction model for severe intraventricular hemorrhage (IVH) in very low birth weight infants (VLBWI). Prospectively collected data of infants with birth weight 500 to 1249 g born between 2001 and 2010 in centers from the Neocosur Network were used. Forward stepwise logistic regression model was employed. The model was tested in the 2011 cohort and then applied to the population of VLBWI that received prophylactic indomethacin to analyze its effect in the risk of severe IVH. Data from 6538 VLBWI were analyzed. The area under ROC curve for the model was 0.79 and 0.76 when tested in the 2011 cohort. The prophylactic indomethacin group had lower incidence of severe IVH, especially in the highest-risk groups. A model for early severe IVH prediction was developed and tested in our population. Prophylactic indomethacin was associated with a lower risk-adjusted incidence of severe IVH.

  18. Delivery mode and intraventricular hemorrhage risk in very-low-birth-weight infants: Observational data of the German Neonatal Network.

    Science.gov (United States)

    Humberg, Alexander; Härtel, Christoph; Paul, Pia; Hanke, Kathrin; Bossung, Verena; Hartz, Annika; Fasel, Laura; Rausch, Tanja K; Rody, Achim; Herting, Egbert; Göpel, Wolfgang

    2017-05-01

    Very-low-birth-weight infants (VLBWI) are frequently delivered by cesarean section (CS). However, it is unclear at what gestational age the benefits of spontaneous delivery outweigh the perinatal risks, i.e. intraventricular hemorrhage (IVH) or death. To assess the short-term outcome of VLBWI on IVH according to mode of delivery in a population-based cohort of the German Neonatal Network (GNN). A total cohort of 2203 singleton VLBWI with a birth weight 30 weeks of gestation prevalence for IVH was not significantly different in VD and planned CS (5.3% vs. 4.4%). Our observational data demonstrate that elective cesarean section is associated with a reduced risk of IVH in preterm infants <30 weeks gestational age when presenting with preterm labor. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Pivotal Role of Brain-Derived Neurotrophic Factor Secreted by Mesenchymal Stem Cells in Severe Intraventricular Hemorrhage in Newborn Rats.

    Science.gov (United States)

    Ahn, So Yoon; Chang, Yun Sil; Sung, Dong Kyung; Sung, Se In; Ahn, Jee-Yin; Park, Won Soon

    2017-01-24

    Mesenchymal stem cell (MSC) transplantation protects against neonatal severe intraventricular hemorrhage (IVH)-induced brain injury by a paracrine rather than regenerative mechanism; however, the paracrine factors involved and their roles have not yet been delineated. This study aimed to identify the paracrine mediator(s) and to determine their role in mediating the therapeutic effects of MSCs in severe IVH. We first identified significant upregulation of brain-derived neurotrophic factor (BDNF) in MSCs compared with fibroblasts, in both DNA and antibody microarrays, after thrombin exposure. We then knocked down BDNF in MSCs by transfection with small interfering (si)RNA specific for human BDNF. The therapeutic effects of MSCs with or without BDNF knockdown were evaluated in vitro in rat neuronal cells challenged with thrombin, and in vivo in newborn Sprague-Dawley rats by injecting 200 μl of blood on postnatal day 4 (P4), and transplanting MSCs (1 × 105 cells) intraventricularly on P6. siRNA-induced BDNF knockdown abolished the in vitro benefits of MSCs on thrombin-induced neuronal cell death. BDNF knockdown also abolished the in vivo protective effects against severe IVH-induced brain injuries such as the attenuation of posthemorrhagic hydrocephalus, impaired behavioral test performance, increased astrogliosis, increased number of TUNEL cells, ED-1+ cells, and inflammatory cytokines, and reduced myelin basic protein expression. Our data indicate that BDNF secreted by transplanted MSCs is one of the critical paracrine factors that play a seminal role in attenuating severe IVH-induced brain injuries in newborn rats.

  20. Positron emission tomography in the newborn: extensive impairment of regional cerebral blood flow with intraventricular hemorrhage and hemorrhagic intracerebral involvement

    International Nuclear Information System (INIS)

    Volpe, J.J.; Herscovitch, P.; Perlman, J.M.; Raichle, M.E.

    1983-01-01

    Positron emission tomography (PET) now provides the capability of measuring regional cerebral blood flow with high resolution and little risk. In this study, we utilized PET in six premature infants (920 to 1,200 g) with major intraventricular hemorrhage and hemorrhagic intracerebral involvement to measure regional cerebral blood flow during the acute period (5 to 17 days of age). Cerebral blood flow was determined after intravenous injection of H 2 O, labeled with the positron-emitting isotope, 15 O. Findings were similar and dramatic in all six infants. In the area of hemorrhagic intracerebral involvement, little or no cerebral blood flow was detected. However, in addition, surprisingly, a marked two- to fourfold reduction in cerebral blood flow was observed throughout the affected hemisphere, well posterior and lateral to the intracerebral hematoma, including cerebral white matter and, to a lesser extent, frontal, temporal, and parietal cortex. In the one infant studied a second time, ie, at 3 months of age, the extent and severity of the decreased cerebral blood flows in the affected hemisphere were similar to those observed on the study during the neonatal period. At the three autopsies, the affected left hemisphere showed extensive infarction, corroborating the PET scans. These observations, the first demonstration of the use of PET in the determination of regional cerebral blood flow in the newborn, show marked impairments in regional cerebral blood flow in the hemisphere containing an apparently restricted intracerebral hematoma, indicating that the hemorrhagic intracerebral involvement is only a component of a much larger lesion, ischemic in basic nature, ie, an infarction. This large ischemic lesion explains the poor neurologic outcome in infants with intraventricular hemorrhage and hemorrhagic intracerebral involvement

  1. UAVs and Control Delays

    National Research Council Canada - National Science Library

    de Vries, S. C

    2005-01-01

    .... Delays of about 250-300 ms often lead to unacceptable airplane handling qualities. Techniques such as filtering and predictive displays may extend the range of acceptable delays up to about 400 ms...

  2. Delayed puberty in boys

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007695.htm Delayed puberty in boys To use the sharing features on this page, please enable JavaScript. Delayed puberty in boys is when puberty does not begin ...

  3. Delayed Orgasm and Anorgasmia

    OpenAIRE

    Jenkins, Lawrence C.; Mulhall, John P.

    2015-01-01

    Delayed orgasm/anorgasmia defined as the persistent or recurrent difficulty, delay in, or absence of attaining orgasm after sufficient sexual stimulation, which causes personal distress. Delayed orgasm and anorgasmia are associated with significant sexual dissatisfaction. A focused medical history can shed light on the potential etiologies; which include: medications, penile sensation loss, endocrinopathies, penile hyperstimulation and psychological etiologies, amongst others. Unfortunately, ...

  4. Hysteresis in conducting ferromagnets

    International Nuclear Information System (INIS)

    Schneider, Carl S.; Winchell, Stephen D.

    2006-01-01

    Maxwell's magnetic diffusion equation is solved for conducting ferromagnetic cylinders to predict a magnetic wave velocity, a time delay for flux penetration and an eddy current field, one of five fields in the linear unified field model of hysteresis. Measured Faraday voltages for a thin steel toroid are shown to be proportional to magnetic field step amplitude and decrease exponentially in time due to maximum rather than average permeability. Dynamic permeabilities are a field convolution of quasistatic permeability and the delay function from which we derive and observe square root dependence of coercivity on rate of field change

  5. Assessment of early diastolic intraventricular pressure gradient in the left ventricle among patients with repaired tetralogy of Fallot.

    Science.gov (United States)

    Kobayashi, Maki; Takahashi, Ken; Yamada, Mariko; Yazaki, Kana; Matsui, Kotoko; Tanaka, Noboru; Shigemitsu, Sachie; Akimoto, Katsumi; Kishiro, Masahiko; Nakanishi, Keisuke; Kawasaki, Shiori; Nii, Masaki; Itatani, Keiichi; Shimizu, Toshiaki

    2017-11-01

    Assessment of left ventricular (LV) dysfunction is vital in patients with repaired tetralogy of Fallot (rTOF). The early diastolic intraventricular pressure gradient (IVPG) in the LV plays an important role in diastolic function. IVPG is calculated as the intraventricular pressure difference divided by the LV length, which allows to account for differences in LV size and therefore calculate IVPG in children. We aimed to investigate the mechanisms of LV diastolic dysfunction by measuring mid-to-apical IVPG as an indicator of the active suction force sucking blood from the left atrium into the LV. We included 38 rTOF patients and 101 healthy controls. The study population was stratified based on age group into children (4-9 years), adolescents (10-15 years), and adults (16-40 years). IVPGs were calculated based on mitral inflow measurements obtained using color M-mode Doppler echocardiography. Although total IVPGs did not differ between rTOF patients and controls, mid-to-apical IVPGs in adolescents and adults were smaller among rTOF patients than among controls (0.15 ± 0.05 vs. 0.21 ± 0.06 mmHg/cm, p < 0.05; 0.09 ± 0.07 vs. 0.17 ± 0.05 mmHg/cm, p < 0.001; respectively). Additionally, only mid-to-apical IVPG correlated linearly with peak circumferential strain (ρ = 0.217, p = 0.011), longitudinal strain (ρ = -0.231, p = 0.006), torsion (ρ = -0.200, p = 0.018), and untwisting rate in early diastole (ρ = -0.233, p = 0.006). In rTOF, the mechanisms underlying diastolic dysfunction involve reduced active suction force, which correlates with reduced LV deformation in all directions.

  6. Dispositivo de assistência circulatória mecânica intraventricular de fluxo axial: estudo in vitro In vitro evaluation of an intraventricular axial flow pump for mechanical circulatory support

    Directory of Open Access Journals (Sweden)

    Luiz Fernando KUBRUSLY

    2000-06-01

    Full Text Available É apresentado estudo in vitro de um dispositivo de assistência circulatória totalmente implantável no ventrículo esquerdo, de fluxo axial e de tamanho pequeno (30 cc - 7 cm comprimento. Apesar dessas características foi capaz de gerar fluxos entre 5 - 8 l/min com motor, operando em 8 W, sem causar hemólise em período de até 12 horas. O custo de produção, excetuando-se o sistema de baterias, foi projetado entre 5 - 8 mil dólares, o que o torna viável para utilização clínica rotineira em nosso país.We are currently studying an intraventricular axial flow blood pump in vitro. It is designed for long term left ventricular support. The small (30 cc, 7 cm length was capable of producing flows of 5 - 8 l/min on a 8 W motor, with no device related hemolysis throughout the 12 h of the study. The cost of production, except for the batteries, has been estimated at between 5 - 8 thousand dollars, a reasonable amount for routine clinical use in Brazil.

  7. Prediction of delayed neurological deficit after subarachnoid haemorrhage: a CT blood load and Doppler velocity approach

    International Nuclear Information System (INIS)

    Grosset, D.G.; McDonald, I.; Cockburn, M.; Straiton, J.; Bullock, R.R.

    1994-01-01

    The predictive value of cranial computed tomography (CT) blood load and serial transcranial Doppler sonography for the development of delayed ischaemic neurological deficit was assessed in 121 patients following subarachnoid haemorrhage. Of the 121 patients, 81 (67 %) had thick layers of blood or haematoma, including intraventricular bleeding. The proportion of patients who developed delayed deficit was higher with increasing amounts of subarachnoid blood on the admission CT (51 % of 53 cases in Fisher grade 3; 35 % of 33 cases in grade 2; 28 % of 7 cases in grade 1, P < 0.01). Doppler velocities obtained from readings at least every 2 days following admission were higher in patients with delayed neurological deficit (peak velocity for grade 3 patients 176 ± 6 cm/s (mean ± SE), versus grade 2: 164 ± 7 cm/s; grade 4 149 ± 9, both P = 0.04, Mann-Whitney). Peak velocity and maximal 24-h rise tended to be higher within different CT grades in patients with a deficit than in those without; this difference was significant for grade 3 patients (P < 0.01). We conclude that a combined approach with CT and Doppler sonography provides greater predictive value for the development of delayed ischaemic neurological deficit than either test considered independently. The value of Doppler sonography may be greatest for patients with Fisher grade 3 blood, in whom the risk of delayed ischaemia is greatest. (orig.)

  8. Physiological Effects of Early Incremental Mobilization of a Patient with Acute Intracerebral and Intraventricular Hemorrhage Requiring Dual External Ventricular Drainage.

    Science.gov (United States)

    Kumble, Sowmya; Zink, Elizabeth K; Burch, Mackenzie; Deluzio, Sandra; Stevens, Robert D; Bahouth, Mona N

    2017-08-01

    Recent trials have challenged the notion that very early mobility benefits patients with acute stroke. It is unclear how cerebral autoregulatory impairments, prevalent in this population, could be affected by mobilization. The safety of mobilizing patients who have external ventricular drainage (EVD) devices for cerebrospinal fluid diversion and intracranial pressure (ICP) monitoring is another concern due to risk of device dislodgment and potential elevation in ICP. We report hemodynamic and ICP responses during progressive, device-assisted mobility interventions performed in a critically ill patient with intracerebral hemorrhage (ICH) requiring two EVDs. A 55-year-old man was admitted to the Neuroscience Critical Care Unit with an acute thalamic ICH and complex intraventricular hemorrhage requiring placement of two EVDs. Progressive mobilization was achieved using mobility technology devices. Range of motion exercises were performed initially, progressing to supine cycle ergometry followed by incremental verticalization using a tilt table. Physiological parameters were recorded before and after the interventions. All mobility interventions were completed without any adverse event or clinically detectable change in the patient's neurological state. Physiological parameters including hemodynamic variables and ICP remained within prescribed goals throughout. Progressive, device-assisted early mobilization was feasible and safe in this critically ill patient with hemorrhagic stroke when titrated by an interdisciplinary team of skilled healthcare professionals. Studies are needed to gain insight into the hemodynamic and neurophysiological responses associated with early mobility in acute stroke to identify subsets of patients who are most likely to benefit from this intervention.

  9. Low-grade intraventricular hemorrhage disrupts cerebellar white matter in preterm infants: evidence from diffusion tensor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Takashi; Morimoto, Masafumi; Hasegawa, Tatsuji; Morioka, Shigemi; Kidowaki, Satoshi; Moroto, Masaharu; Yamashita, Satoshi; Maeda, Hiroshi; Chiyonobu, Tomohiro; Tokuda, Sachiko; Hosoi, Hajime [Kyoto Prefectural University of Medicine, Department of Pediatrics, Graduate School of Medical Science, Kyoto (Japan); Yamada, Kei [Kyoto Prefectural University of Medicine, Department of Radiology, Graduate School of Medical Science, Kyoto (Japan)

    2015-05-01

    Recent diffusion tensor imaging (DTI) studies have demonstrated that leakage of hemosiderin into cerebrospinal fluid (CSF), which is caused by high-grade intraventricular hemorrhage (IVH), can affect cerebellar development in preterm born infants. However, a direct effect of low-grade IVH on cerebellar development is unknown. Thus, we evaluated the cerebellar and cerebral white matter (WM) of preterm infants with low-grade IVH. Using DTI tractography performed at term-equivalent age, we analyzed 42 infants who were born less than 30 weeks gestational age (GA) at birth (22 with low-grade IVH, 20 without). These infants were divided into two birth groups depending on GA, and we then compared the presence and absence of IVH which was diagnosed by cerebral ultrasound (CUS) within 10 days after birth or conventional magnetic resonance imaging (MRI) at term-equivalent age in each group. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) at the superior cerebellar peduncle (SCP), middle cerebellar peduncle (MCP), motor tract, and sensory tract were measured. In the SCP, preterm born infants with IVH had lower FA values compared with infants without IVH. In particular, younger preterm birth with IVH had lower FA values in the SCP and motor tract and higher ADC values in the MCP. Low-grade IVH impaired cerebellar and cerebral WM, especially in the SCP. Moreover, younger preterm infants exhibited greater disruptions to cerebellar WM and the motor tract than infants of older preterm birth. (orig.)

  10. Biochemical markers may identify preterm infants with a patent ductus arteriosus at high risk of death or severe intraventricular haemorrhage.

    Science.gov (United States)

    El-Khuffash, A; Barry, D; Walsh, K; Davis, P G; Molloy, E J

    2008-11-01

    A patent ductus arteriosus (PDA) in preterm infants is associated with increased risk of intraventricular haemorrhage (IVH) and death. Cardiac troponin T (cTnT) and N-terminal-pro-B type natriuretic peptide (NTpBNP) are markers of cardiac function and can predict poor outcome in adults. To determine whether echocardiography and cTnT/NTpBNP levels at 48 h predict death before discharge or severe IVH in preterm infants with a PDA. Infants born closure (NTpBNP 9282, 5121 and 740 pmol/l, respectively, p = 0.008, and cTnT 0.66, 0.25 and 0.13 microg/l, respectively, p = 0.027). There were no differences in echocardiographic parameters of PDA size, left atrial to aortic ratio (LA:Ao), left and right ventricular outputs between the PDA groups. NTpBNP and cTnT in conjunction with echocardiography may provide a basis for trials of targeted medical treatment in infants with a PDA.

  11. Reduced cerebral blood flow and oxygen metabolism in extremely preterm neonates with low-grade germinal matrix- intraventricular hemorrhage

    Science.gov (United States)

    Lin, Pei-Yi; Hagan, Katherine; Fenoglio, Angela; Grant, P. Ellen; Franceschini, Maria Angela

    2016-05-01

    Low-grade germinal matrix-intraventricular hemorrhage (GM-IVH) is the most common complication in extremely premature neonates. The occurrence of GM-IVH is highly associated with hemodynamic instability in the premature brain, yet the long-term impact of low-grade GM-IVH on cerebral blood flow and neuronal health have not been fully investigated. We used an innovative combination of frequency-domain near infrared spectroscopy and diffuse correlation spectroscopy (FDNIRS-DCS) to measure cerebral oxygen saturation (SO2) and an index of cerebral blood flow (CBFi) at the infant’s bedside and compute an index of cerebral oxygen metabolism (CMRO2i). We enrolled twenty extremely low gestational age (ELGA) neonates (seven with low-grade GM-IVH) and monitored them weekly until they reached full-term equivalent age. During their hospital stay, we observed consistently lower CBFi and CMRO2i in ELGA neonates with low-grade GM-IVH compared to neonates without hemorrhages. Furthermore, lower CBFi and CMRO2i in the former group persists even after the resolution of the hemorrhage. In contrast, SO2 does not differ between groups. Thus, CBFi and CMRO2i may have better sensitivity than SO2 in detecting GM-IVH-related effects on infant brain development. FDNIRS-DCS methods may have clinical benefit for monitoring the evolution of GM-IVH, evaluating treatment response, and potentially predicting neurodevelopmental outcome.

  12. Delayed orgasm and anorgasmia.

    Science.gov (United States)

    Jenkins, Lawrence C; Mulhall, John P

    2015-11-01

    Delayed orgasm/anorgasmia defined as the persistent or recurrent difficulty, delay in, or absence of attaining orgasm after sufficient sexual stimulation, which causes personal distress. Delayed orgasm and anorgasmia are associated with significant sexual dissatisfaction. A focused medical history can shed light on the potential etiologies, which include medications, penile sensation loss, endocrinopathies, penile hyperstimulation, and psychological etiologies. Unfortunately, there are no excellent pharmacotherapies for delayed orgasm/anorgasmia, and treatment revolves largely around addressing potential causative factors and psychotherapy. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  13. Prehospital delay in acute coronary syndrome--an analysis of the components of delay

    DEFF Research Database (Denmark)

    Ottesen, Michael Mundt; Dixen, Ulrik; Torp-Pedersen, Christian

    2004-01-01

    BACKGROUND: Prompt hospital admission is essential when treating acute coronary syndrome. Delay prior to admission is unnecessarily long. Therefore, a thorough scrutiny of the influence of characteristics, circumstantial and subjective variables on elements of prehospital delay among patients...... admitted with acute coronary syndrome is warranted. METHODS: A structured interview was conducted on 250 consecutive patients admitted alive with acute coronary syndrome. RESULTS: Median prehospital, decision, physician and transportation delays were 107, 74, 25 and 22 min, respectively. Women (n=77) had...... of acute coronary syndrome among women, and thereby contributes to unnecessary long delay to treatment. The patient's prior experience and interpretation has a significant influence on behaviour....

  14. American Dream Delayed

    DEFF Research Database (Denmark)

    Khorunzhina, Natalia; Miller, Robert A.

    This paper investigates the delay in homeownership and a subsequent reduction in homeownership rate observed over the past decades. We focus on the delay in giving birth to children and increased labor market participation as contributing factors to homeownership dynamics for prime-age female hou...

  15. Air congestion delay: a review

    Directory of Open Access Journals (Sweden)

    Daniel Alberto Pamplona

    2016-04-01

    Full Text Available This article is a literature review of the air congestion delay and its costs. Air congestion is a worldwide problem. Its existence brings costs for airlines and discomfort for passengers. With the increasing demand for air transport, the study of air congestion has attracted the attention of many researchers around the world. The cause for the delays is erroneously attributed only to the lack of infrastructure investments. The literature review shows that other factors such as population growth, increasing standards of living, lack of operational planning and environmental issues exercise decisive influence. Several studies have been conducted in order to analyze and propose solutions to this problem that affects society as a whole.

  16. Conducting Polymers

    Indian Academy of Sciences (India)

    would exhibit electronic conductivity, their conductivities (of compressed pellets) were indeed measured by others, and were found to be .... Polyaniline. Polyphenylene. Polypheny lene- vinylene. Table 1. G!NeRAl I ARTICl! structure. Maximum conductivity Stem Stability. Processability. ~. 1.5 x 105. Reacts with Film not n air.

  17. Superficial Siderosis of the Central Nervous System Caused by Hemorrhagic Intraventricular Craniopharyngioma: Case Report and Literature Review

    Science.gov (United States)

    TOSAKA, Masahiko; SATO, Koji; AMANUMA, Makoto; HIGUCHI, Tetsuya; ARAI, Motohiro; AISHIMA, Kaoru; SHIMIZU, Tatsuya; HORIGUCHI, Keishi; SUGAWARA, Kenichi; YOSHIMOTO, Yuhei

    2015-01-01

    Superficial siderosis is a rare condition caused by hemosiderin deposits in the central nervous system (CNS) due to prolonged or recurrent low-grade bleeding into the cerebrospinal fluid (CSF). CNS tumor could be one of the sources of bleeding, both pre- and postoperatively. We report an extremely rare case of superficial siderosis associated with purely third ventricle craniopharyngioma, and review previously reported cases of superficial siderosis associated with CNS tumor. A 69-year-old man presented with headache, unsteady gait, blurred vision, and progressive hearing loss. Brain magnetic resonance (MR) imaging with gadolinium revealed a well enhanced, intraventricular mass in the anterior part of the third ventricle. T2*-weighted gradient echo (GE) MR imaging revealed a hypointense rim around the brain particularly marked within the depth of the sulci. Superficial siderosis was diagnosed based on these findings. The tumor was diffusely hypointense on T2*-weighted GE imaging, indicating intratumoral hemorrhage. The lateral ventricles were dilated, suggesting hydrocephalus. [18F]fluorodeoxyglucose positron emission tomography revealed increased uptake in the tumor. The whole brain surface appeared dark ocher at surgery. Histological examination showed the hemorrhagic tumor was papillary craniopharyngioma. His hearing loss progressed after removal of the tumor. T2*-weighted GE MR imaging demonstrated not only superficial siderosis but also diffuse intratumoral hemorrhage in the tumor. Superficial siderosis and its related symptoms, including hearing loss, should be considered in patients with hemorrhagic tumor related to the CSF space. Purely third ventricle craniopharyngioma rarely has hemorrhagic character, which could cause superficial siderosis and progressive hearing loss. PMID:24670310

  18. Chronic intraventricular administration of lysergic acid diethylamide (LSD) affects the sensitivity of cortical cells to monocular deprivation.

    Science.gov (United States)

    McCall, M A; Tieman, D G; Hirsch, H V

    1982-11-04

    In kittens, but not in adult cats, depriving one eye of pattern vision by suturing the lids shut (monocular deprivation or MD) for one week reduces the proportion of binocular units in the visual cortex. A sensitivity of cortical units in adult cats to MD can be produced by infusing exogenous monoamines into the visual cortex. Since LSD interacts with monoamines, we have examined the effects of chronic administration of LSD on the sensitivity to MD for cortical cells in adult cats. Cats were assigned randomly to one of four conditions: MD/LSD, MD/No-LSD, No-MD/LSD, No-MD/No-LSD. An osmotic minipump delivered either LSD or the vehicle solution alone during a one-week period of MD. The animals showed no obvious anomalies during the administration of the drug. After one week the response properties of single units in area 17 of the visual cortex were studied without knowledge of the contents of the individual minipumps. With the exception of ocular dominance, the response properties of units recorded in all animals did not differ from normal. In the control animals (MD/No-LSD, No-MD/LSD, No-MD/No-LSD) the average proportion of binocular cells was 78%; similar to that observed for normal adult cats. However, in the experimental animals, which received LSD during the period of MD, only 52% of the cells were binocular. Our results suggest that chronic intraventricular administration of LSD affects either directly or indirectly the sensitivity of cortical neurons to MD.

  19. Trends in hospitalization of preterm infants with intraventricular hemorrhage and hydrocephalus in the United States, 2000-2010.

    Science.gov (United States)

    Christian, Eisha A; Jin, Diana L; Attenello, Frank; Wen, Timothy; Cen, Steven; Mack, William J; Krieger, Mark D; McComb, J Gordon

    2016-03-01

    OBJECT Even with improved prenatal and neonatal care, intraventricular hemorrhage (IVH) occurs in approximately 25%-30% of preterm infants, with a subset of these patients developing hydrocephalus. This study was undertaken to describe current trends in hospitalization of preterm infants with posthemorrhagic hydrocephalus (PHH) using the Nationwide Inpatient Sample (NIS) and the Kids' Inpatient Database (KID). METHODS The KID and NIS were combined to generate data for the years 2000-2010. All neonatal discharges with ICD-9-CM codes for preterm birth with IVH alone or with IVH and hydrocephalus were included. RESULTS There were 147,823 preterm neonates with IVH, and 9% of this group developed hydrocephalus during the same admission. Of patients with Grade 3 and 4 IVH, 25% and 28%, respectively, developed hydrocephalus in comparison with 1% and 4% of patients with Grade 1 and 2 IVH, respectively. Thirty-eight percent of patients with PHH had permanent ventricular shunts inserted. Mortality rates were 4%, 10%, 18%, and 40%, respectively, for Grade 1, 2, 3, and 4 IVH during initial hospitalization. Length of stay has been trending upward for both groups of IVH (49 days in 2000, 56 days in 2010) and PHH (59 days in 2000, 70 days in 2010). The average hospital cost per patient (adjusted for inflation) has also increased, from $201,578 to $353,554 (for IVH) and $260,077 to $495,697 (for PHH) over 11 years. CONCLUSIONS The number of neonates admitted with IVH has increased despite a decrease in the number of preterm births. Rates of hydrocephalus and mortality correlated closely with IVH grade. The incidence of hydrocephalus in preterm infants with IVH remained stable between 8% and 10%. Over an 11-year period, there was a progressive increase in hospital cost and length of stay for preterm neonates with IVH and PHH that may be explained by a concurrent increase in the proportion of patients with congenital cardiac anomalies.

  20. Neonatal Acute Kidney Injury and the Risk of Intraventricular Hemorrhage in the Very Low Birth Weight Infant.

    Science.gov (United States)

    Stoops, Christine; Sims, Brian; Griffin, Russell; Askenazi, D J

    2016-01-01

    Despite improvements in survival of premature infants, many have comorbid conditions. The role of the kidney in multiorgan dysfunction is unclear, particularly in regard to intraventricular hemorrhage (IVH). We hypothesized that infants diagnosed with acute kidney injury (AKI) have an increased risk of IVH independent of gestational age (GA) and other variables associated with both comorbidities. This prospective cohort study consisted of 125 infants with a birth weight ≤1,200 g and/or GA ≤31 weeks. A definition of AKI was used from KDIGO, not including urine output as nonoliguria is common in this population. IVH was based on serial head ultrasounds. Neonates with AKI had a higher trend towards having IVH compared to those without [14/35 (40%) vs. 22/83 (26.5%), p = 0.1]. Infants with AKI were more likely to have stage 2 IVH or higher than those without AKI [12/36 (33.3%) vs. 6/82 (7.3%); p < 0.01]. AKI was associated with a 3.6-fold increased risk of a grade 2 or higher IVH [hazard ratio (HR) 3.55, 95% confidence interval (CI) 1.39-9.07] and over 4-fold increase in risk of a grade 3 or higher IVH (HR 4.34, 95% CI 1.43-13.21). While there was no association between AKI and IVH overall, those with AKI had a higher hazard ratio to develop a grade 2 or higher IVH even when controlling for birth weight, antenatal steroid use, and 5-min Apgar score. Future studies are indicated to expand sample size and to control for other clinical variables that could be associated with both AKI and IVH. © 2016 S. Karger AG, Basel.

  1. Delayed power analysis

    International Nuclear Information System (INIS)

    Adamovich, L.A.; Azarov, V.V.

    1999-01-01

    Time dependent core power behavior in a nuclear reactor is described with well-known neutron kinetics equations. At the same time, two portions are distinguished in energy released from uranium nuclei fission; one released directly at fission and another delayed (residual) portion produced during radioactive decay of fission products. While prompt power is definitely described with kinetics equations, the delayed power presentation still remains outstanding. Since in operation the delayed power part is relatively small (about 6%) operation, it can be neglected for small reactivity disturbances assuming that entire power obeys neutron kinetics equations. In case of a high negative reactivity rapidly inserted in core (e.g. reactor scram initiation) the prompt and delayed components can be calculated separately with practically no impact on each other, employing kinetics equations for prompt power and known approximation formulas for delayed portion, named residual in this specific case. Under substantial disturbances the prompt component in the dynamic process becomes commensurable with delayed portion, thus making necessary to take into account their cross impact. A system of differential equations to describe time-dependent behavior of delayed power is presented. Specific NPP analysis shows a way to significantly simplify the task formulation. (author)

  2. Delayed radiation neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, T.; Miyamoto, K.; Beppu, H.; Hirose, K.; Yamada, K. (Tokyo Metropolitan Neurological Hospital (Japan))

    1981-07-01

    A case of cervical plexus neuropathy was reported in association with chronic radio-dermatitis, myxedema with thyroid adenoma and epiglottic tumor. A 38-year-old man has noticed muscle weakness and wasting of the right shoulder girdle since age 33. A detailed history taking revealed a previous irradiation to the neck because of the cervical lymphadenopathy at age 10 (X-ray 3,000 rads), keroid skin change at age 19, obesity and edema since 26, and hoarseness at 34. Laryngoscopic examination revealed a tumor on the right vocal cord, diagnosed as benign papilloma by histological study. In addition, there were chronic radio-dermatitis around the neck, primary hypothyroidism with a benign functioning adenoma on the right lobe of the thyroid, the right phrenic nerve palsy and the right recurrent nerve palsy. All these lesions were considered to be the late sequellae of radiation to the neck in childhood. Other neurological signs were weakness and amyotrophy of the right shoulder girdle with patchy sensory loss, and areflexia of the right arm. Gross power was fairly well preserved in the right hand. EMG showed neurogenic changes in the tested muscles, suggesting a peripheral nerve lesion. Nerve conduction velocities were normal. No abnormal findings were revealed by myelography and spinal CT. The neurological findings of the patient were compatible with the diagnosis of middle cervical plexus palsy apparently due to late radiation effect. In the literature eight cases of post-radiation neuropathy with a long latency have been reported. The present case with the longest latency after the radiation should be included in the series of the reported cases of ''delayed radiation neuropathy.'' (author).

  3. Delayed radiation neuropathy

    International Nuclear Information System (INIS)

    Nagashima, Toshiko; Miyamoto, Kazuto; Beppu, Hirokuni; Hirose, Kazuhiko; Yamada, Katsuhiro

    1981-01-01

    A case of cervical plexus neuropathy was reported in association with chronic radio-dermatitis, myxedema with thyroid adenoma and epiglottic tumor. A 38-year-old man has noticed muscle weakness and wasting of the right shoulder girdle since age 33. A detailed history taking revealed a previous irradiation to the neck because of the cervical lymphadenopathy at age 10 (X-ray 3,000 rads), keroid skin change at age 19, obesity and edema since 26, and hoarseness at 34. Laryngoscopic examination revealed a tumor on the right vocal cord, diagnosed as benign papilloma by histological study. In addition, there were chronic radio-dermatitis around the neck, primary hypothyroidism with a benign functioning adenoma on the right lobe of the thyroid, the right phrenic nerve palsy and the right recurrent nerve palsy. All these lesions were considered to be the late sequellae of radiation to the neck in childhood. Other neurological signs were weakness and amyotrophy of the right shoulder girdle with patchy sensory loss, and areflexia of the right arm. Gross power was fairly well preserved in the right hand. EMG showed neurogenic changes in the tested muscles, suggesting a peripheral nerve lesion. Nerve conduction velocities were normal. No abnormal findings were revealed by myelography and spinal CT. The neurological findings of the patient were compatible with the diagnosis of middle cervical plexus palsy apparently due to late radiation effect. In the literature eight cases of post-radiation neuropathy with a long latency have been reported. The present case with the longest latency after the radiation should be included in the series of the reported cases of ''delayed radiation neuropathy.'' (author)

  4. Maternal Obesity: Risks for Developmental Delays in Early Childhood.

    Science.gov (United States)

    Duffany, Kathleen O'Connor; McVeigh, Katharine H; Kershaw, Trace S; Lipkind, Heather S; Ickovics, Jeannette R

    2016-02-01

    To assess the risk for neurodevelopmental delays for children of mothers who were obese (≥200 pounds) prior to pregnancy, and to characterize delays associated with maternal obesity among children referred to and found eligible to receive Early Intervention Program services. We conducted a retrospective cohort study (N = 541,816) using a population-based New York City data warehouse with linked birth and Early Intervention data. Risks for children suspected of a delay and 'significantly delayed', with two moderate or one severe delay, were calculated. Among the group of children eligible by delay for Early Intervention, analyses assessed risk for being identified with a moderate-to-severe delay across each of five functional domains as well as risks for multiple delays. Children of mothers who were obese were more likely to be suspected of a delay (adjusted RR 1.19 [CI 1.15-1.22]) and borderline association for 'significantly delayed' (adjusted RR 1.01 [CI 1.00-1.02). Among children eligible by delay, children of mothers who were obese evidenced an increased risk for moderate-to-severe cognitive (adjusted RR 1.04 [CI 1.02-1.07]) and physical (adjusted RR 1.04 [CI 1.01-1.08]) delays and for global developmental delay (adjusted RR 1.05 [CI 1.01-1.08]). Maternal obesity is associated with increased risk of developmental delay in offspring. Among children with moderate or severe delays, maternal obesity is associated with increased risk of cognitive and physical delays as well as with increased risk for global developmental delay. While causation remains uncertain, this adds to the growing body of research reporting an association between maternal obesity and neurodevelopmental delays in offspring.

  5. Neutron delayed choice experiments

    International Nuclear Information System (INIS)

    Bernstein, H.J.

    1986-01-01

    Delayed choice experiments for neutrons can help extend the interpretation of quantum mechanical phenomena. They may also rule out alternative explanations which static interference experiments allow. A simple example of a feasible neutron test is presented and discussed. (orig.)

  6. Quad nanosecond delay module

    International Nuclear Information System (INIS)

    McDonald, R.J.; Hunter, J.B.; Wozniak, G.J.

    1986-04-01

    Four nanosecond (ns) delay units have been designed to fit in a single-width NIM module. This module is particularly suited for use in conjunction with quad constant fraction timing discriminators (CFTDs) since it has four delay units that can be placed adjacent to the four units of the CFTD. A series of different length cables connected via DIP toggle switches provide delays of 0.60 ns in 4 ns increments. Thus, the CFTD delay can be optimized for pulses of different rise times from approx.10-100 ns. Design work for the PC board and silkscreening of the front panel were done with the MacDraw program on the Apple Mackintosh computer and printed with the Lasewriter printer. 6 refs

  7. Delayed rule following

    OpenAIRE

    Schmitt, David R.

    2001-01-01

    Although the elements of a fully stated rule (discriminative stimulus [SD], some behavior, and a consequence) can occur nearly contemporaneously with the statement of the rule, there is often a delay between the rule statement and the SD. The effects of this delay on rule following have not been studied in behavior analysis, but they have been investigated in rule-like settings in the areas of prospective memory (remembering to do something in the future) and goal pursuit. Discriminative even...

  8. Vernier Delay Unit

    International Nuclear Information System (INIS)

    Pierce, W.B.

    1984-10-01

    This module will accept differential ECL pulses from the auxiliary rear panel or NIM level pulses from the front panel. The pulses are produced at the output with a fixed delay that is software programmable in steps of 0.1 ns over the range of 0.1 to 10.5 ns. Multiple outputs are available at the front panel. Minimum delay through the module is 9 ns

  9. Quad precision delay generator

    International Nuclear Information System (INIS)

    Krishnan, Shanti; Gopalakrishnan, K.R.; Marballi, K.R.

    1997-01-01

    A Quad Precision Delay Generator delays a digital edge by a programmed amount of time, varying from nanoseconds to microseconds. The output of this generator has an amplitude of the order of tens of volts and rise time of the order of nanoseconds. This was specifically designed and developed to meet the stringent requirements of the plasma focus experiments. Plasma focus is a laboratory device for producing and studying nuclear fusion reactions in hot deuterium plasma. 3 figs

  10. Modelling delays in pharmacokinetics

    International Nuclear Information System (INIS)

    Farooqi, Z.H.; Lambrecht, R.M.

    1990-01-01

    Linear system analysis has come to form the backbone of pharmacokinetics. Natural systems usually involve time delays, thus models incorporating them would be an order closer approximation to the real world compared to those that do not. Delays may be modelled in several ways. The approach considered in this study is to have a discrete-time delay dependent rate with the delay respresenting the duration between the entry of a drug into a compartment and its release in some form (may be as a metabolite) from the compartment. Such a delay may be because of one or more of several physiological reasons, like, formation of a reservoir, slow metabolism, or receptor binding. The mathematical structure this gives rise to is a system of delay-differential equations. Examples are given of simple one and two compartment systems with drugs like bumetanide, carbamazepine, and quinolone-caffeine interaction. In these examples generally a good fit is obtained and the suggested models form a good approximation. 21 refs., 6 figs

  11. Heat conduction

    International Nuclear Information System (INIS)

    Grigull, U.; Sandner, H.

    1984-01-01

    Included are discussions of rates of heat transfer by conduction, the effects of varying and changing properties, thermal explosions, distributed heat sources, moving heat sources, and non-steady three-dimensional conduction processes. Throughout, the importance of thinking both numerically and symbolically is stressed, as this is essential to the development of the intuitive understanding of numerical values needed for successful designing. Extensive tables of thermophysical properties, including thermal conductivity and diffusivity, are presented. Also included are exact and approximate solutions to many of the problems that arise in practical situations

  12. The experimental investigation of glioma-trophic capacity of human umbilical cord-derived mesenchymal stem cells after intraventricular administration

    Directory of Open Access Journals (Sweden)

    FAN Cun-gang

    2013-07-01

    Full Text Available Objective To explore the glioma-trophic migration capacity of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs by intraventricular administration. Methods The umbilical cord tissue were obtained during full-term pregnancy cesarean section under sterile conditions. This study was approved by Ethics Committee and got the informed consent of patient. The hUC-MSCs were isolated by trypsin and collagenase digestion, followed by adherent culture methods. The characteristics of isolated hUC-MSCs were demonstrated by cell morphylogy, phenotype analysis and multi-differentiation potentials into adipocytes, osteoblasts and neural cells. Then the hUC-MSCs were labeled with CM-DiI and injected into contralateral ventricle of glioma of the C6 glioma-bearing Sprague-Dawley (SD rats. Two weeks later, the rats were sacrificed and the brains were taken out to examine the migration and distribution of hUC-MSCs in the tumor bed, at the interface of tumor and cerebral parenchyma as well as the tumor satelites infiltrating into the normal brain. Results The hUC-MSCs demonstrated plastic-adherent characterization and homogeneous fibroblastic-like morphylogy in culture, expression of specific surface phenotypes of MSCs (CD13, CD29, CD44, CD90 but not endothelial or hematopoietic markers (CD14, CD31, CD34, CD38, CD45, CD133, and muti-differentiatiation potentials into Oil red O stained adipocytes, Alizarin red S stained osteoblasts, neuron-specific enolase (NSE-positive neurons and glial fibrillary acidic protein (GFAP-positive astrocytes in permissive inducive conditions. Importantly, after labeled hUC-MSCs injection into contralateral ventricle of glioma, the hUC-MSCs migrated from initial injection site to the glioma mass and along the interface of tumor and brain, and some of them "chasing" the glioma satellites infiltrated into the normal parenchyma. Conclusion The hUC-MSCs possess prominent tumor-specific targeting capacity and extensive intratumoral

  13. Exercise-induced intra-ventricular gradients as a frequent potential cause of myocardial ischemia in cardiac syndrome X patients

    Directory of Open Access Journals (Sweden)

    Almeida Ana G

    2008-01-01

    Full Text Available Abstract Background The development of intra-ventricular gradients (IVG during dobutamine or exercise stress is not infrequent, and can be associated to symptoms during stress. The purpose of this study was to assess the occurrence of IVG during exercise stress echocardiography in cardiac syndrome X patients. Methods We prospectively evaluated 91 patients (pts mean aged 51 ± 12 years (age ranged 20 to 75 years old, 44 of whom were women. All pts had angina, positive exercise ECG treadmill testing, normal rest echocardiogram and no coronary artery disease on coronary angiogram (cardiac X syndrome. After complete Doppler echocardiographic evaluation with determination of left ventricular outflow tract index (LVOTi, relative left ventricular wall thickness (RLVWT and left ventricular end-diastolic volume index (LVDVi, all patients underwent stress echocardiography with two-dimensional and Doppler echographic evaluation during and after treadmill exercise. Results For analysis purpose patients were divided in 2 groups, according to the development of IVG. Doppler evidence of IVG was found in 33 (36% of the patients (Group A, with mean age 47 ± 14 years old (age ranged 20 to 72 years and with a mean end-systolic peak gradient of 86 ± 34 mmHg (ranging from 30 to 165 mmHg. The IVG development was accompanied by SAM of the mitral valve in 23 pts. Three of these pts experienced symptomatic hypotension. Ten were women (30% pts. 58 pts in group B, 34 of whom were women (59% (p = 0,01 vs group A, mean aged 53,5 ± 10,9 years old (age ranged 34 to 75 years (p = 0,03 vs group A, did not develop IVG. LVOTi was 10,29 ± 0,9 mm/m2 in group A and 11,4 ± 1 mm/m2 in group B (p 2 in group A and 56 ± 11,6 ml/m2 in group B (p = 0,000. Conclusion 1. A significant number of patients with cardiac X syndrome developed IVG during upright exercise in treadmill. These pts (group A are mainly males and younger than those who did not develop IVG. 2. The development of IVG

  14. Electrical Conductivity.

    Science.gov (United States)

    Hershey, David R.; Sand, Susan

    1993-01-01

    Explains how electrical conductivity (EC) can be used to measure ion concentration in solutions. Describes instrumentation for the measurement, temperature dependence and EC, and the EC of common substances. (PR)

  15. Conduct Disorder

    Science.gov (United States)

    ... objections runs away from home often truant from school Children who exhibit these behaviors should receive a comprehensive evaluation by an experience mental health professional. Many children with a conduct disorder may ...

  16. Pattern of labelling of the rat brain stem after intraventricular administration of 3H-leucine; low and high resolution autoradiographic study

    International Nuclear Information System (INIS)

    Jakoubek, B.; Jirmanova, I.; Soukup, T.; Krekule, I.

    1982-01-01

    The pattern of labelling proteins of the periventricular grey matter was studied two hours after intraventricular administration of 3 H-leucine by low- and high-resolution autoradiography. The pattern was investigated by computer-controlled densitometry. The deposition of radioactive proteins in periventricular grey surrounding the mesencephalic part of the aquaeductus Sylvii was compared with that surrounding the fourth ventricle. In the former case, the distribution of grains was in a circular area 500 to 600 μm in diameter; the densitometric tracing revealed a homogeneous distribution of the label; in the latter case, the distribution was nonhomogeneous and was limited by the tissue components forming the wall of the fourth ventricle. A comparison of the intensity of labelling (performed by a combination of low- and high-resolution autoradiography) indicated relatively substantial labelling of proteins of ependymal cells, very sparce labelling of subependymal layers, and very high labelling of neurones adjacent to the subependymal layer. The significance of these findings for the interpretation of studies using intraventricular administration of labelled amino acids for investigating brain macromolecular metabolism is discussed. (author)

  17. Optimal Joint Expected Delay Forwarding in Delay Tolerant Networks

    OpenAIRE

    Jia Xu; Xin Feng; Wen Jun Yang; Ru Chuan Wang; Bing Qing Han

    2013-01-01

    Multicopy forwarding schemes have been employed in delay tolerant network (DTN) to improve the delivery delay and delivery rate. Much effort has been focused on reducing the routing cost while retaining high performance. This paper aims to provide an optimal joint expected delay forwarding (OJEDF) protocol which minimizes the expected delay while satisfying a certain constant on the number of forwardings per message. We propose a comprehensive forwarding metric called joint expected delay (JE...

  18. Head midline position for preventing the occurrence or extension of germinal matrix-intraventricular hemorrhage in preterm infants.

    Science.gov (United States)

    Romantsik, Olga; Calevo, Maria Grazia; Bruschettini, Matteo

    2017-07-20

    Preterm birth is known to constitute the major risk factor for development of germinal matrix-intraventricular hemorrhage (GM-IVH). Head position may affect cerebral hemodynamics and thus may be involved indirectly in development of GM-IVH. Turning the head toward one side may functionally occlude jugular venous drainage on the ipsilateral side while increasing intracranial pressure and cerebral blood volume. Thus, it has been suggested that cerebral venous pressure is reduced and hydrostatic brain drainage improved if the patient is in supine midline position with the bed tilted 30°. The midline position might be achieved in the supine position and, with the use of physical aids, in the lateral position as well. Midline position should be kept, at least when the incidence of GM-IVH is greatest, that is, during the first two to three days of life. Primary objective To assess whether head midline position is more effective than any other head position for preventing or extending germinal matrix-intraventricular hemorrhage in infants born at ≤ 32 weeks' gestational age. Secondary objectives To perform subgroup analyses regarding gestational age, birth weight, intubated versus not intubated, and with or without GM-IVH at trial entry. We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8), MEDLINE via PubMed (1966 to September 19, 2016), Embase (1980 to September 19,.2016), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to September 19, 2016). We searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials. Randomized clinical controlled trials, quasi-randomized trials, and cluster-randomized controlled trials comparing placing very preterm infants in a head midline position versus placing them in a prone or lateral decubitus

  19. Adult intraventricular craniopharyngioma

    International Nuclear Information System (INIS)

    Chin, H.W.

    1983-01-01

    A case of craniopharyngioma with unusual location confined within the third ventricle is reported. The 56 years old adult presented with symptoms and signs of increased intracranial pressure. There were no characteristic findings of craniopharyngioma in X-ray examinations, but computed tomography scan showed a mass lesion in the third ventricle. Literature survey revealed nine cases of craniopharyngioma developed solely within the third ventricle. (orig.) [de

  20. Adult intraventricular craniopharyngioma

    Energy Technology Data Exchange (ETDEWEB)

    Chin, H.W.

    1983-04-01

    A case of craniopharyngioma with unusual location confined within the third ventricle is reported. The 56 years old adult presented with symptoms and signs of increased intracranial pressure. There were no characteristic findings of craniopharyngioma in X-ray examinations, but computed tomography scan showed a mass lesion in the third ventricle. Literature survey revealed nine cases of craniopharyngioma developed solely within the third ventricle.

  1. Echo determinants of dyssynchrony (atrioventricular and inter- and intraventricular) and predictors of response to cardiac resynchronization therapy.

    Science.gov (United States)

    Kapetanakis, Stamatis; Bhan, Amit; Monaghan, Mark J

    2008-10-01

    Cardiac resynchronization therapy (CRT) has revolutionized not only the treatment of chronic heart failure but also how we assess left ventricular (LV) dysfunction on echo. Increasingly, it has become clear that identifying and quantifying delays in events during the cardiac cycle is an important assessment in LV dysfunction as it has prognostic implications for patients undergoing CRT. The delays in atrioventricular, right-to-left ventricular, and LV segmental contraction have been shown to be important components in cardiac performance, and this review provides an overview of the commonest methods used for these assessments and their implications for selecting patients for biventricular pacing.

  2. Conduct disorders

    NARCIS (Netherlands)

    Buitelaar, J.K.; Smeets, K.C.; Herpers, P.; Scheepers, F.; Glennon, J.; Rommelse, N.N.J.

    2013-01-01

    Conduct disorder (CD) is a frequently occurring psychiatric disorder characterized by a persistent pattern of aggressive and non-aggressive rule breaking antisocial behaviours that lead to considerable burden for the patients themselves, their family and society. This review paper updates diagnostic

  3. Tuberculous Lymphadenitis: Skin Delayed-Type Hypersensitivity ...

    African Journals Online (AJOL)

    Tuberculous Lymphadenitis: Skin Delayed-Type Hypersensitivity Reaction and Cellular Immune Responses. ... The tuberculin skin test (TST) and peripheral blood mono-nuclear cells (PBMCs) culture were conducted using PPD. The cytokines were measured using commercial kits. Results: The mean TST was 24.6 ±8.0 ...

  4. Estimating Delays In ASIC's

    Science.gov (United States)

    Burke, Gary; Nesheiwat, Jeffrey; Su, Ling

    1994-01-01

    Verification is important aspect of process of designing application-specific integrated circuit (ASIC). Design must not only be functionally accurate, but must also maintain correct timing. IFA, Intelligent Front Annotation program, assists in verifying timing of ASIC early in design process. This program speeds design-and-verification cycle by estimating delays before layouts completed. Written in C language.

  5. Permissible Delay in Payments

    Directory of Open Access Journals (Sweden)

    Yung-Fu Huang

    2007-01-01

    Full Text Available The main purpose of this paper wants to investigate the optimal retailer's lot-sizing policy with two warehouses under partially permissible delay in payments within the economic order quantity (EOQ framework. In this paper, we want to extend that fully permissible delay in payments to the supplier would offer the retailer partially permissible delay in payments. That is, the retailer must make a partial payment to the supplier when the order is received. Then the retailer must pay off the remaining balance at the end of the permissible delay period. In addition, we want to add the assumption that the retailer's storage space is limited. That is, the retailer will rent the warehouse to store these exceeding items when the order quantity is larger than retailer's storage space. Under these conditions, we model the retailer's inventory system as a cost minimization problem to determine the retailer's optimal cycle time and optimal order quantity. Three theorems are developed to efficiently determine the optimal replenishment policy for the retailer. Finally, numerical examples are given to illustrate these theorems and obtained a lot of managerial insights.

  6. Delayed neutrons in ANSTO

    International Nuclear Information System (INIS)

    Wall, T.

    1988-01-01

    Delayed neutron analysis carried out at the Australian Nuclear Scientific and Technology Organization facilities, provides a fast, high sensitivity, low cost, reliable method, particularly suitable for large batches of samples, and for non destructive analysis of a range of materials. While its main use has been in uranium exploration, other applications include archeological investigations, agriculture, oceanography and biology

  7. Conductivity Probe

    Science.gov (United States)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air. The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air. The needles on the probe are 15 millimeters (0.6 inch) long. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  8. System delays in breast cancer | Dalwai | South African Journal of ...

    African Journals Online (AJOL)

    Background: Centralised multidisciplinary management of breast cancer occurs in KwaZulu-Natal, South Africa, and requires a diagnostic and staging pathway at the referring hospital. Delays in this pathway are unknown. This study, conducted at a referring hospital, R K Khan (RKK), quantifies and analyses these delays.

  9. Topological Acoustic Delay Line

    Science.gov (United States)

    Zhang, Zhiwang; Tian, Ye; Cheng, Ying; Wei, Qi; Liu, Xiaojun; Christensen, Johan

    2018-03-01

    Topological protected wave engineering in artificially structured media is at the frontier of ongoing metamaterials research that is inspired by quantum mechanics. Acoustic analogues of electronic topological insulators have recently led to a wealth of new opportunities in manipulating sound propagation with strikingly unconventional acoustic edge modes immune to backscattering. Earlier fabrications of topological insulators are characterized by an unreconfigurable geometry and a very narrow frequency response, which severely hinders the exploration and design of useful devices. Here we establish topologically protected sound in reconfigurable phononic crystals that can be switched on and off simply by rotating its three-legged "atoms" without altering the lattice structure. In particular, we engineer robust phase delay defects that take advantage of the ultrabroadband reflection-free sound propagation. Such topological delay lines serve as a paradigm in compact acoustic devices, interconnects, and electroacoustic integrated circuits.

  10. Delayed traumatic intracranial hematoma

    International Nuclear Information System (INIS)

    Tomita, Hiroki

    1984-01-01

    CT was performed serially within 24 hours after head injury in 64 patients having Glasgow Coma Scale of 14 or less or cranial fracture shown on roentgenogram. Delayed traumatic extradural hematoma was observed within 7-12 hours after head injury in 6 cases (9.4%). This was prominent in the frontal and occipital regions (67%). Good recovery was seen in 83.3%. Delayed traumatic intracerebral hematoma was observed within 6-24 hours after head injury in 17 cases (26.6%). This higher incidence was related to contre coup injury. Conservative treatment was possible in 14 of the 17 patients (82.4%), showing good recovery in 70%. (Namekawa, K.)

  11. Time-Delay Interferometry

    Directory of Open Access Journals (Sweden)

    Massimo Tinto

    2014-08-01

    Full Text Available Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers, the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI. This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

  12. Conduct disorders.

    Science.gov (United States)

    Buitelaar, Jan K; Smeets, Kirsten C; Herpers, Pierre; Scheepers, Floor; Glennon, Jeffrey; Rommelse, Nanda N J

    2013-02-01

    Conduct disorder (CD) is a frequently occurring psychiatric disorder characterized by a persistent pattern of aggressive and non-aggressive rule breaking antisocial behaviours that lead to considerable burden for the patients themselves, their family and society. This review paper updates diagnostic and therapeutic approaches to CD in the light of the forthcoming DSM-5 definition. The diagnostic criteria for CD will remain unchanged in DSM-5, but the introduction of a specifier of CD with a callous-unemotional (CU) presentation is new. Linked to this, we discuss the pros and cons of various other ways to subtype aggression/CD symptoms. Existing guidelines for CD are, with few exceptions, already of a relatively older date and emphasize that clinical assessment should be systematic and comprehensive and based on a multi-informant approach. Non-medical psychosocial interventions are recommended as the first option for the treatment of CD. There is a role for medication in the treatment of comorbid syndromes and/or in case of insufficient response to psychosocial interventions and severe and dangerous aggressive and violent behaviours.

  13. Delayed child-bearing.

    Science.gov (United States)

    Johnson, Jo-Ann; Tough, Suzanne

    2012-01-01

    To provide an overview of delayed child-bearing and to describe the implications for women and health care providers. Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices. Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues. Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely

  14. Delaying information search

    Directory of Open Access Journals (Sweden)

    Yaniv Shani

    2012-11-01

    Full Text Available In three studies, we examined factors that may temporarily attenuate information search. People are generally curious and dislike uncertainty, which typically encourages them to look for relevant information. Despite these strong forces that promote information search, people sometimes deliberately delay obtaining valuable information. We find they may do so when they are concerned that the information might interfere with future pleasurable activities. Interestingly, the decision to search or to postpone searching for information is influenced not only by the value and importance of the information itself but also by well-being maintenance goals related to possible detrimental effects that negative knowledge may have on unrelated future plans.

  15. Vehicle barrier with access delay

    Science.gov (United States)

    Swahlan, David J; Wilke, Jason

    2013-09-03

    An access delay vehicle barrier for stopping unauthorized entry into secure areas by a vehicle ramming attack includes access delay features for preventing and/or delaying an adversary from defeating or compromising the barrier. A horizontally deployed barrier member can include an exterior steel casing, an interior steel reinforcing member and access delay members disposed within the casing and between the casing and the interior reinforcing member. Access delay members can include wooden structural lumber, concrete and/or polymeric members that in combination with the exterior casing and interior reinforcing member act cooperatively to impair an adversarial attach by thermal, mechanical and/or explosive tools.

  16. Delayed rule following.

    Science.gov (United States)

    Schmitt, D R

    2001-01-01

    Although the elements of a fully stated rule (discriminative stimulus [S(D)], some behavior, and a consequence) can occur nearly contemporaneously with the statement of the rule, there is often a delay between the rule statement and the S(D). The effects of this delay on rule following have not been studied in behavior analysis, but they have been investigated in rule-like settings in the areas of prospective memory (remembering to do something in the future) and goal pursuit. Discriminative events for some behavior can be event based (a specific setting stimulus) or time based. The latter are more demanding with respect to intention following and show age-related deficits. Studies suggest that the specificity with which the components of a rule (termed intention) are stated has a substantial effect on intention following, with more detailed specifications increasing following. Reminders of an intention, too, are most effective when they refer specifically to both the behavior and its occasion. Covert review and written notes are two effective strategies for remembering everyday intentions, but people who use notes appear not to be able to switch quickly to covert review. By focusing on aspects of the setting and rule structure, research on prospective memory and goal pursuit expands the agenda for a more complete explanation of rule effects.

  17. Pseudotumoral delayed cerebral radionecrosis

    International Nuclear Information System (INIS)

    Ciaudo-Lacroix, C.; Lapresle, J.

    1985-01-01

    A 60 year-old woman with a scalp epithelioma underwent radiotherapy, the dose being 57 Gray. A first epileptic seizure occurred twenty months later. Neurological examination revealed signs of left hemisphere involvement. γEG, angiography, CT scans, demonstrated a pseudotumoral avascular process. On account of the localisation, the patient being right-handed, no surgical procedure was performed. In spite of corticotherapy and anticonvulsive treatment, seizures recurred and neurological signs slowly progressed. The patient died, 22 months after the first seizure, of an associated disseminated carcinoma with cachexia. Neuropathological examination showed a massive lesion presenting all the features of delayed radionecrosis in the left hemisphere: situated mainly in the white matter; numerous vascular abnormalities; wide-spread demyelination; disappearance of oligoglial cells. The Authors recall the clinical and anatomical aspects of this condition for which the only successful treatment is surgical removal when location and size of the lesion permit. Finally, the mechanisms which have been proposed to explain this delayed cerebral radionecrosis are discussed [fr

  18. Pseudotumoral delayed cerebral radionecrosis

    Energy Technology Data Exchange (ETDEWEB)

    Ciaudo-Lacroix, C; Lapresle, J [Centre Hospitalier de Bicetre, 94 - Le Kremlin-Bicetre (France)

    1985-01-01

    A 60 year-old woman with a scalp epithelioma underwent radiotherapy, the dose being 57 Gray. A first epileptic seizure occurred twenty months later. Neurological examination revealed signs of left hemisphere involvement. ..gamma..EG, angiography, CT scans, demonstrated a pseudotumoral avascular process. On account of the localisation, the patient being right-handed, no surgical procedure was performed. In spite of corticotherapy and anticonvulsive treatment, seizures recurred and neurological signs slowly progressed. The patient died, 22 months after the first seizure, of an associated disseminated carcinoma with cachexia. Neuropathological examination showed a massive lesion presenting all the features of delayed radionecrosis in the left hemisphere: situated mainly in the white matter; numerous vascular abnormalities; wide-spread demyelination; disappearance of oligoglial cells. The Authors recall the clinical and anatomical aspects of this condition for which the only successful treatment is surgical removal when location and size of the lesion permit. Finally, the mechanisms which have been proposed to explain this delayed cerebral radionecrosis are discussed.

  19. REASONS FOR PATIENT DELAYS & HEALTH SYSTEM DELAYS FOR TUBERCULOSIS IN SOUTH INDIA

    Directory of Open Access Journals (Sweden)

    Kapil Goel

    2011-12-01

    Full Text Available Background: Globally, the burden of Tuberculosis is escalating. Early diagnosis and prompt initiation of tuberculosis treatment is essential for an effective tuberculosis control programme. Objectives: To study the self reported reasons for patient and health system (diagnosis & treatment delays in Tuberculosis patients. Methods: A community based cross sectional study was conducted among 98 new sputum positive TB cases aged > 15 years registered under RNTCP from Oct 2006 to June 2007 & receiving treatment under DOTS in Udupi taluk by interviewing them. Results: Total 98 patients were recruited and 68% were males. Out of 17 patients with patient delays, 82% felt that their symptoms were not severe, 71% felt that patient delay was due to lack of awareness and 71% did not take it seriously. Out of 86 patients with health system delays, 82.6% of patients mentioned that doctor has not advised for sputum examination, 76.7% of patients told that they first consulted a private doctor, 21% of them mentioned that doctor was unaware to diagnose TB. Conclusion: Symptoms not severe is the main reason for the patient delay and doctor didn’t advise for sputum examination is the main reason for health system delays.

  20. Research On Variable-Length Transfer Delay and Delayed Signal Cancellation Based PLLs

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2018-01-01

    large frequency drifts are anticipated and a high accuracy is required. To the best of authors' knowledge, the small-signal modeling of a variable-length delay-based PLL has not yet been conducted. The main aim of this paper is to cover this gap. The tuning procedure and analysis of these PLLs...

  1. Stability and delay sensitivity of neutral fractional-delay systems.

    Science.gov (United States)

    Xu, Qi; Shi, Min; Wang, Zaihua

    2016-08-01

    This paper generalizes the stability test method via integral estimation for integer-order neutral time-delay systems to neutral fractional-delay systems. The key step in stability test is the calculation of the number of unstable characteristic roots that is described by a definite integral over an interval from zero to a sufficient large upper limit. Algorithms for correctly estimating the upper limits of the integral are given in two concise ways, parameter dependent or independent. A special feature of the proposed method is that it judges the stability of fractional-delay systems simply by using rough integral estimation. Meanwhile, the paper shows that for some neutral fractional-delay systems, the stability is extremely sensitive to the change of time delays. Examples are given for demonstrating the proposed method as well as the delay sensitivity.

  2. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne

    2012-01-01

    We evaluated the association between radiation therapy and severe capsular contracture or reoperation after 717 delayed breast implant reconstruction procedures (288 1- and 429 2-stage procedures) identified in the prospective database of the Danish Registry for Plastic Surgery of the Breast during...... of radiation therapy was associated with a non-significantly increased risk of reoperation after both 1-stage (HR = 1.4; 95% CI: 0.7-2.5) and 2-stage (HR = 1.6; 95% CI: 0.9-3.1) procedures. Reconstruction failure was highest (13.2%) in the 2-stage procedures with a history of radiation therapy. Breast...... reconstruction approaches other than implants should be seriously considered among women who have received radiation therapy....

  3. Delay tolerant networks

    CERN Document Server

    Gao, Longxiang; Luan, Tom H

    2015-01-01

    This brief presents emerging and promising communication methods for network reliability via delay tolerant networks (DTNs). Different from traditional networks, DTNs possess unique features, such as long latency and unstable network topology. As a result, DTNs can be widely applied to critical applications, such as space communications, disaster rescue, and battlefield communications. The brief provides a complete investigation of DTNs and their current applications, from an overview to the latest development in the area. The core issue of data forward in DTNs is tackled, including the importance of social characteristics, which is an essential feature if the mobile devices are used for human communication. Security and privacy issues in DTNs are discussed, and future work is also discussed.

  4. Location Estimation using Delayed Measurements

    DEFF Research Database (Denmark)

    Bak, Martin; Larsen, Thomas Dall; Nørgård, Peter Magnus

    1998-01-01

    When combining data from various sensors it is vital to acknowledge possible measurement delays. Furthermore, the sensor fusion algorithm, often a Kalman filter, should be modified in order to handle the delay. The paper examines different possibilities for handling delays and applies a new techn...... technique to a sensor fusion system for estimating the location of an autonomous guided vehicle. The system fuses encoder and vision measurements in an extended Kalman filter. Results from experiments in a real environment are reported...

  5. Modeling delay in genetic networks: from delay birth-death processes to delay stochastic differential equations.

    Science.gov (United States)

    Gupta, Chinmaya; López, José Manuel; Azencott, Robert; Bennett, Matthew R; Josić, Krešimir; Ott, William

    2014-05-28

    Delay is an important and ubiquitous aspect of many biochemical processes. For example, delay plays a central role in the dynamics of genetic regulatory networks as it stems from the sequential assembly of first mRNA and then protein. Genetic regulatory networks are therefore frequently modeled as stochastic birth-death processes with delay. Here, we examine the relationship between delay birth-death processes and their appropriate approximating delay chemical Langevin equations. We prove a quantitative bound on the error between the pathwise realizations of these two processes. Our results hold for both fixed delay and distributed delay. Simulations demonstrate that the delay chemical Langevin approximation is accurate even at moderate system sizes. It captures dynamical features such as the oscillatory behavior in negative feedback circuits, cross-correlations between nodes in a network, and spatial and temporal information in two commonly studied motifs of metastability in biochemical systems. Overall, these results provide a foundation for using delay stochastic differential equations to approximate the dynamics of birth-death processes with delay.

  6. Modeling delay in genetic networks: From delay birth-death processes to delay stochastic differential equations

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Chinmaya; López, José Manuel; Azencott, Robert; Ott, William [Department of Mathematics, University of Houston, Houston, Texas 77004 (United States); Bennett, Matthew R. [Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77204, USA and Institute of Biosciences and Bioengineering, Rice University, Houston, Texas 77005 (United States); Josić, Krešimir [Department of Mathematics, University of Houston, Houston, Texas 77004 (United States); Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204 (United States)

    2014-05-28

    Delay is an important and ubiquitous aspect of many biochemical processes. For example, delay plays a central role in the dynamics of genetic regulatory networks as it stems from the sequential assembly of first mRNA and then protein. Genetic regulatory networks are therefore frequently modeled as stochastic birth-death processes with delay. Here, we examine the relationship between delay birth-death processes and their appropriate approximating delay chemical Langevin equations. We prove a quantitative bound on the error between the pathwise realizations of these two processes. Our results hold for both fixed delay and distributed delay. Simulations demonstrate that the delay chemical Langevin approximation is accurate even at moderate system sizes. It captures dynamical features such as the oscillatory behavior in negative feedback circuits, cross-correlations between nodes in a network, and spatial and temporal information in two commonly studied motifs of metastability in biochemical systems. Overall, these results provide a foundation for using delay stochastic differential equations to approximate the dynamics of birth-death processes with delay.

  7. Modeling delay in genetic networks: From delay birth-death processes to delay stochastic differential equations

    International Nuclear Information System (INIS)

    Gupta, Chinmaya; López, José Manuel; Azencott, Robert; Ott, William; Bennett, Matthew R.; Josić, Krešimir

    2014-01-01

    Delay is an important and ubiquitous aspect of many biochemical processes. For example, delay plays a central role in the dynamics of genetic regulatory networks as it stems from the sequential assembly of first mRNA and then protein. Genetic regulatory networks are therefore frequently modeled as stochastic birth-death processes with delay. Here, we examine the relationship between delay birth-death processes and their appropriate approximating delay chemical Langevin equations. We prove a quantitative bound on the error between the pathwise realizations of these two processes. Our results hold for both fixed delay and distributed delay. Simulations demonstrate that the delay chemical Langevin approximation is accurate even at moderate system sizes. It captures dynamical features such as the oscillatory behavior in negative feedback circuits, cross-correlations between nodes in a network, and spatial and temporal information in two commonly studied motifs of metastability in biochemical systems. Overall, these results provide a foundation for using delay stochastic differential equations to approximate the dynamics of birth-death processes with delay

  8. Systematic of delayed neutron parameters

    International Nuclear Information System (INIS)

    Isaev, S.G.; Piksaikin, V.M.

    2000-01-01

    The experimental studies of the energy dependence of the delayed neutron (DN) parameters for various fission systems has shown that the behaviour of a some combination of delayed neutron parameters has a similar features. On the basis of this findings the systematics of delayed neutron experimental data for thorium, uranium, plutonium and americium isotopes have been investigated with the purpose to find a correlation of DN parameters with characteristics of fissioning system as well as a correlation between the delayed neutron parameters themselves. It was presented the preliminary results which were obtained during study the physics interpretation of the results [ru

  9. Time Delay of CGM Sensors

    Science.gov (United States)

    Schmelzeisen-Redeker, Günther; Schoemaker, Michael; Kirchsteiger, Harald; Freckmann, Guido; Heinemann, Lutz; del Re, Luigi

    2015-01-01

    Background: Continuous glucose monitoring (CGM) is a powerful tool to support the optimization of glucose control of patients with diabetes. However, CGM systems measure glucose in interstitial fluid but not in blood. Rapid changes in one compartment are not accompanied by similar changes in the other, but follow with some delay. Such time delays hamper detection of, for example, hypoglycemic events. Our aim is to discuss the causes and extent of time delays and approaches to compensate for these. Methods: CGM data were obtained in a clinical study with 37 patients with a prototype glucose sensor. The study was divided into 5 phases over 2 years. In all, 8 patients participated in 2 phases separated by 8 months. A total number of 108 CGM data sets including raw signals were used for data analysis and were processed by statistical methods to obtain estimates of the time delay. Results: Overall mean (SD) time delay of the raw signals with respect to blood glucose was 9.5 (3.7) min, median was 9 min (interquartile range 4 min). Analysis of time delays observed in the same patients separated by 8 months suggests a patient dependent delay. No significant correlation was observed between delay and anamnestic or anthropometric data. The use of a prediction algorithm reduced the delay by 4 minutes on average. Conclusions: Prediction algorithms should be used to provide real-time CGM readings more consistent with simultaneous measurements by SMBG. Patient specificity may play an important role in improving prediction quality. PMID:26243773

  10. Finding determinants of audit delay by pooled OLS regression analysis

    Directory of Open Access Journals (Sweden)

    Tina Vuko

    2014-03-01

    Full Text Available The aim of this paper is to investigate determinants of audit delay. Audit delay is measured as the length of time (i.e. the number of calendar days from the fiscal year-end to the audit report date. It is important to understand factors that influence audit delay since it directly affects the timeliness of financial reporting. The research is conducted on a sample of Croatian listed companies, covering the period of four years (from 2008 to 2011. We use pooled OLS regression analysis, modelling audit delay as a function of the following explanatory variables: audit firm type, audit opinion, profitability, leverage, inventory and receivables to total assets, absolute value of total accruals, company size and audit committee existence. Our results indicate that audit committee existence, profitability and leverage are statistically significant determinants of audit delay in Croatia.

  11. Ranking of Delay Factors for Makkah’s Construction Industry

    Directory of Open Access Journals (Sweden)

    Al-Emad Nashwan

    2017-01-01

    Full Text Available This paper presents identification of significant delay factors encountered by Makkah’s construction industry using quantitative approach. A structured questionnaire developed based on literature review was verified through pilot study involved selected construction experts. Questionnaire survey was conducted amongst Makkah construction practitioners include contractors, consultants and project management consultancy. The survey managed to collect 100 valid responses which were used to rank the factors using average index approach. Results of the analysis for 10 most significant factors causing construction delay in Makkah construction industry are Difficulties in financing project by contractor, Poor coordination between parties, Shortage of manpower, Delays in producing design documents, Improper planning and scheduling of the project, Delay in progress payments, Low productivity level of labour, Poor communication between parties, Unqualified workforce and Poor contract management. This finding is helpful to Makkah construction’s community particularly projects’ stakeholders in avoiding potential delay for their future projects.

  12. [Late arrhythmias in the operated interatrial communication. Analysis of sinus node function and the conduction pathways by His bundle electrocardiography].

    Science.gov (United States)

    Ramírez, A; Gil, M; Martínez Ríos, M A; Cárdenas, M; Pliego, J; Zamora, C; Mata, L A

    1982-01-01

    Four hundred patients with atrial septal defect treated surgically were reviewed. Thirty five (8.7%) developed arrhytmias post-surgery which persisted for over a year. Sinus bradycardia was found in 10 patients, nodal rhythm in 21, and atrial fibrilation and flutter in 4 patients. Thirty five per cent of the patients with late arrhythmias developed related symptomatology. In 14 patients the function of the sinus node was studied with electrical stimulation of the atrium and with His registry. The interatrial conduction time, AV node and His Purkinje were analized employing various stimulation frequencies. All the cases studied had normal intra-atrial conduction; the response of the atrio-ventricular node to increasing frequencies was normal, an the intraventricular conduction remained constant. In 8 patients (52%), alterations of the sinus node were found; these consisted of prolonged post-stimulation pauses, Wenckebach's type sinoatrial block and suppression of sinus automatism employing vagal procedures or through electrical stimulation. A patient with severe bradycardia detected by dynamic electrocardiography had to be treated with a permanent pacemaker. We confirm that these arrhytmias are not produced by lesions of the internodal tracts, and that an alteration of the sinus node is frequent without a concomitant lesion of the intraventricular pathway. The lesion to the nutrient artery could be due to trauma and/or surgically induced. The response to anticholinergic drugs was good. Prolonged observation of these patients could increase the morbility of these arrythmias and raise doubts of the surgical indications in cases with moderate hemodynamic repercussion.

  13. Factors influencing diagnosis delay of advanced breast cancer in Moroccan women

    OpenAIRE

    Maghous, A.; Rais, F.; Ahid, S.; Benhmidou, N.; Bellahamou, K.; Loughlimi, H.; Marnouche, E.; Elmajjaoui, S.; Elkacemi, H.; Kebdani, T.; Benjaafar, N.

    2016-01-01

    Background Delay in the diagnosis of breast cancer in symptomatic women of 3?months or more is associated with advanced stage and low survival. We conducted this study to learn more about the extent and reasons behind diagnosis delay of advanced breast cancer in Moroccan women. Methods A group of patients with advanced breast cancer were interviewed at the National Institute of Oncology in Rabat during the period from February to December 2014. Diagnosis delay was devised into patient delay a...

  14. Delayed Auditory Feedback and Movement

    Science.gov (United States)

    Pfordresher, Peter Q.; Dalla Bella, Simone

    2011-01-01

    It is well known that timing of rhythm production is disrupted by delayed auditory feedback (DAF), and that disruption varies with delay length. We tested the hypothesis that disruption depends on the state of the movement trajectory at the onset of DAF. Participants tapped isochronous rhythms at a rate specified by a metronome while hearing DAF…

  15. #FakeNobelDelayReasons

    CERN Multimedia

    2013-01-01

    Tuesday’s hour-long delay of the Nobel Prize in Physics announcement was (and still is) quite the cause for speculation. But on the Twittersphere, it was simply the catalyst for some fantastic puns, so-bad-they're-good physics jokes and other shenanigans. Here are some of our favourite #FakeNobelDelayReasons.    

  16. Picosecond resolution programmable delay line

    International Nuclear Information System (INIS)

    Suchenek, Mariusz

    2009-01-01

    The note presents implementation of a programmable delay line for digital signals. The tested circuit has a subnanosecond delay range programmable with a resolution of picoseconds. Implementation of the circuit was based on low-cost components, easily available on the market. (technical design note)

  17. The effects of mild germinal matrix-intraventricular haemorrhage on the developmental white matter microstructure of preterm neonates. A DTI study

    International Nuclear Information System (INIS)

    Tortora, Domenico; Martinetti, Carola; Severino, Mariasavina; Morana, Giovanni; Rossi, Andrea; Uccella, Sara; Brera, Fabia; Malova, Mariya; Parodi, Alessandro; Ramenghi, Luca Antonio

    2018-01-01

    To evaluate white matter (WM) microstructural changes in preterm neonates (PN) with mild germinal matrix-intraventricular haemorrhage (mGMH-IVH) (grades I and II) and no other associated MRI abnormalities, and correlate them with gestational age (GA) and neurodevelopmental outcome. Tract-based spatial-statistics (TBSS) was performed on DTI of 103 patients studied at term-equivalent age, to compare diffusional parameters (fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD)) between mGMH-IVH neonates (24/103) and controls matched by GA at birth and sex. The relationship between DTI abnormalities, GA and neurodevelopmental outcome assessed with Griffiths' Developmental Scale-Revised:0-2 was explored using TBSS and Spearman-correlation analysis (p <.05). Affected neonates had lower FA, higher RD and MD of the corpus callosum, limbic pathways and cerebellar tracts. Extremely preterm neonates (GA < 29 weeks) presented more severe microstructural impairment (higher RD and MD) in periventricular regions. Neonates of GA ≥ 29 weeks had milder WM alterations (lower FA), also in subcortical WM. DTI abnormalities were associated with poorer locomotor, eye-hand coordination and performance outcomes at 24 months. WM microstructural changes occur in PN with mGMH-IVH with a GA-dependent selective vulnerability of WM regions, and correlate with adverse neurodevelopmental outcome at 24 months. (orig.)

  18. The effects of mild germinal matrix-intraventricular haemorrhage on the developmental white matter microstructure of preterm neonates. A DTI study

    Energy Technology Data Exchange (ETDEWEB)

    Tortora, Domenico; Martinetti, Carola; Severino, Mariasavina; Morana, Giovanni; Rossi, Andrea [Istituto Giannina Gaslini, Neuroradiology Unit, Genoa (Italy); Uccella, Sara; Brera, Fabia [Istituto Giannina Gaslini, Neuropsychiatry Unit, Genoa (Italy); Malova, Mariya; Parodi, Alessandro; Ramenghi, Luca Antonio [Istituto Giannina Gaslini, Neonatal Intensive Care Unit, Genoa (Italy)

    2018-03-15

    To evaluate white matter (WM) microstructural changes in preterm neonates (PN) with mild germinal matrix-intraventricular haemorrhage (mGMH-IVH) (grades I and II) and no other associated MRI abnormalities, and correlate them with gestational age (GA) and neurodevelopmental outcome. Tract-based spatial-statistics (TBSS) was performed on DTI of 103 patients studied at term-equivalent age, to compare diffusional parameters (fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD)) between mGMH-IVH neonates (24/103) and controls matched by GA at birth and sex. The relationship between DTI abnormalities, GA and neurodevelopmental outcome assessed with Griffiths' Developmental Scale-Revised:0-2 was explored using TBSS and Spearman-correlation analysis (p <.05). Affected neonates had lower FA, higher RD and MD of the corpus callosum, limbic pathways and cerebellar tracts. Extremely preterm neonates (GA < 29 weeks) presented more severe microstructural impairment (higher RD and MD) in periventricular regions. Neonates of GA ≥ 29 weeks had milder WM alterations (lower FA), also in subcortical WM. DTI abnormalities were associated with poorer locomotor, eye-hand coordination and performance outcomes at 24 months. WM microstructural changes occur in PN with mGMH-IVH with a GA-dependent selective vulnerability of WM regions, and correlate with adverse neurodevelopmental outcome at 24 months. (orig.)

  19. Project delay analysis of HRSG

    Science.gov (United States)

    Silvianita; Novega, A. S.; Rosyid, D. M.; Suntoyo

    2017-08-01

    Completion of HRSG (Heat Recovery Steam Generator) fabrication project sometimes is not sufficient with the targeted time written on the contract. The delay on fabrication process can cause some disadvantages for fabricator, including forfeit payment, delay on HRSG construction process up until HRSG trials delay. In this paper, the author is using semi quantitative on HRSG pressure part fabrication delay with configuration plant 1 GT (Gas Turbine) + 1 HRSG + 1 STG (Steam Turbine Generator) using bow-tie analysis method. Bow-tie analysis method is a combination from FTA (Fault tree analysis) and ETA (Event tree analysis) to develop the risk matrix of HRSG. The result from FTA analysis is use as a threat for preventive measure. The result from ETA analysis is use as impact from fabrication delay.

  20. Delayed or early sowing

    NARCIS (Netherlands)

    Tippe, Dennis E.; Rodenburg, Jonne; Ast, van Aad; Anten, Niels P.R.; Dieng, Ibnou; Kayeke, Juma; Cissoko, Mamadou; Bastiaans, Lammert

    2017-01-01

    Parasitic weeds are a severe problem in rain-fed rice production ecosystems in sub-Saharan Africa. In this study, effects of sowing time of rice on parasitic weed infection and crop yields were investigated. Field experiments were conducted in Striga asiatica-infested upland and Rhamphicarpa

  1. Finding determinants of audit delay by pooled OLS regression analysis

    OpenAIRE

    Vuko, Tina; Čular, Marko

    2014-01-01

    The aim of this paper is to investigate determinants of audit delay. Audit delay is measured as the length of time (i.e. the number of calendar days) from the fiscal year-end to the audit report date. It is important to understand factors that influence audit delay since it directly affects the timeliness of financial reporting. The research is conducted on a sample of Croatian listed companies, covering the period of four years (from 2008 to 2011). We use pooled OLS regression analysis, mode...

  2. Cardiac Delayed Rectifier Potassium Channels in Health and Disease

    Science.gov (United States)

    Chen, Lei; Sampson, Kevin J.; Kass, Robert S.

    2016-01-01

    Cardiac delayed rectifier potassium channels conduct outward potassium currents during the plateau phase of action potentials and play pivotal roles in cardiac repolarization. These include IKs, IKr and the atrial specific IKur channels. In this chapter, we will review the molecular identities and biophysical properties of these channels. Mutations in the genes encoding delayed rectifiers lead to loss- or gain-of-function phenotypes, disrupt normal cardiac repolarization and result in various cardiac rhythm disorders, including congenital Long QT Syndrome, Short QT Syndrome and familial atrial fibrillation. We will also discuss the possibility and prospect of using delayed rectifier channels as therapeutic targets to manage cardiac arrhythmia. PMID:27261823

  3. Cardiac Delayed Rectifier Potassium Channels in Health and Disease.

    Science.gov (United States)

    Chen, Lei; Sampson, Kevin J; Kass, Robert S

    2016-06-01

    Cardiac delayed rectifier potassium channels conduct outward potassium currents during the plateau phase of action potentials and play pivotal roles in cardiac repolarization. These include IKs, IKr and the atrial specific IKur channels. In this article, we will review their molecular identities and biophysical properties. Mutations in the genes encoding delayed rectifiers lead to loss- or gain-of-function phenotypes, disrupt normal cardiac repolarization and result in various cardiac rhythm disorders, including congenital Long QT Syndrome, Short QT Syndrome and familial atrial fibrillation. We will also discuss the prospect of using delayed rectifier channels as therapeutic targets to manage cardiac arrhythmia. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Prevalence and determinants of delay in diagnosis of pulmonary tuberculosis in Darjeeling district of West Bengal

    Directory of Open Access Journals (Sweden)

    Sibasis Das

    2017-01-01

    Full Text Available Background: Delayed diagnosis of tuberculosis (TB is a significant problem both in individual as well as community level. Different studies around globe revealed that these diagnostic delays are attributed to both patient delay and health system-related delay. Aims: This study aims to assess the magnitude of delay in diagnosis and the association with sociodemographic profile among new sputum-positive pulmonary TB patients in Darjeeling district. Materials and Methods: A cross-sectional study was conducted among 374 TB patients from October 2011 to March 2012 using a predesigned pretested schedule by face-to-face interview. Statistical Analysis: Logistic regression analysis, odds ratios (OR, adjusted ORs. Results: Patient delay, health system delay and total diagnostic delay were 27 days, 20.1 days, and 20.6 days; mean delays were 23.64, 5.71, and 29.46 days, and median delays were 25, 5, and 32 days, respectively. Risk factors associated with patient delay were female gender, rural residence, illiteracy, smoking, alcohol consumption, taking two, or more alternate treatments; for health system delay were female sex, rural residence, time to reach health facility, time spent per visit; and for total diagnostic delay were female sex, alcoholism, and seeking more than two alternate treatment. Conclusions: The risk factors for delay identified may be the subject of future interventions.

  5. Attosecond Delays in Molecular Photoionization.

    Science.gov (United States)

    Huppert, Martin; Jordan, Inga; Baykusheva, Denitsa; von Conta, Aaron; Wörner, Hans Jakob

    2016-08-26

    We report measurements of energy-dependent photoionization delays between the two outermost valence shells of N_{2}O and H_{2}O. The combination of single-shot signal referencing with the use of different metal foils to filter the attosecond pulse train enables us to extract delays from congested spectra. Remarkably large delays up to 160 as are observed in N_{2}O, whereas the delays in H_{2}O are all smaller than 50 as in the photon-energy range of 20-40 eV. These results are interpreted by developing a theory of molecular photoionization delays. The long delays measured in N_{2}O are shown to reflect the population of molecular shape resonances that trap the photoelectron for a duration of up to ∼110 as. The unstructured continua of H_{2}O result in much smaller delays at the same photon energies. Our experimental and theoretical methods make the study of molecular attosecond photoionization dynamics accessible.

  6. DRAWING SKILLS IN CHILDREN WITH NEURODEVELOPMENTAL DELAY AGED 2-5 YEARS.

    Science.gov (United States)

    Morović, Maja Lang; Matijević, Valentina; Divljaković, Kristina; Kraljević, Marija; Dimić, Zdenka

    2015-06-01

    In typically developing children, drawing development occurs in stages from uncontrolled strokes to complex drawing. In this study, we examined drawing development in children with neurodevelopmental delay (NDD). In order to do so, we observed the influence of age, intraventricular hemorrhage (IVH) and gender on the development of drawing skills. The sample consisted of 52 children with NDD, aged 2 years and 6 months to 5 years. All children were hospitalized for multidisciplinary team monitoring and developmental support. The evaluation of drawing development was administered by giving each child a blank A4 paper and the instruction to draw anything they wanted. All of the drawings were scored satisfactory or unsatisfactory. Descriptive statistics was employed on all relevant data to show results in frequencies and percentages. In order to determine differences between groups, the χ2-test was administered. The results showed greatest difference in drawing in children aged from 3 years to 3 years and 11 months. Children with lower IVH had better drawing scores than children with higher IVH levels. According to gender dissimilarities, a difference was found showing girls to have better drawing skills than boys. All study results pointed to the importance of early rehabilitation and continuous structured work with children with NDD.

  7. Fundamentals of Delayed Coking Joint Industry Project

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk; Keith Wisecarver

    2003-09-26

    is 2,937,439 barrels/calendar day. These cokers produce 154,607 tons of coke per day and delayed coking accounts for 88% of the world capacity. The delayed coking charge capacity in the United States is 1,787,860 b/cd. Despite its wide commercial use, only relatively few contractors and refiners are truly knowledgeable in delayed-coking design, so that this process carries with it a ''black art'' connotation. Until recently, the expected yield from cokers was determined by a simple laboratory test on the feedstock. As a result of Tulsa University's prior related research, a process model was developed that with additional work could be used to optimize existing delayed cokers over a wide range of potential feedstocks and operating conditions. The objectives of this research program are to: utilize the current micro, batch and pilot unit facilities at The University of Tulsa to enhance the understanding of the coking process; conduct additional micro and pilot unit tests with new and in-house resids and recycles to make current optimization models more robust; conduct focused kinetic experiments to enhance the furnace tube model and to enhance liquid production while minimizing sulfur in the products; conduct detailed foaming studies to optimize the process and minimize process upsets; quantify the parameters that affect coke morphology; and to utilize the knowledge gained from the experimental and modeling studies to enhance the computer programs developed in the previous JIP for optimization of the coking process. These refined computer models will then be tested against refinery data provided by the member companies. Novel concepts will also be explored for hydrogen sulfide removal of furnace gases as well as gas injection studies to reduce over-cracking.

  8. Delays and networked control systems

    CERN Document Server

    Hetel, Laurentiu; Daafouz, Jamal; Johansson, Karl

    2016-01-01

    This edited monograph includes state-of-the-art contributions on continuous time dynamical networks with delays. The book is divided into four parts. The first part presents tools and methods for the analysis of time-delay systems with a particular attention on control problems of large scale or infinite-dimensional systems with delays. The second part of the book is dedicated to the use of time-delay models for the analysis and design of Networked Control Systems. The third part of the book focuses on the analysis and design of systems with asynchronous sampling intervals which occur in Networked Control Systems. The last part of the book exposes several contributions dealing with the design of cooperative control and observation laws for networked control systems. The target audience primarily comprises researchers and experts in the field of control theory, but the book may also be beneficial for graduate students. .

  9. Linear rotary optical delay lines

    Science.gov (United States)

    Guerboukha, Hichem; Qu, Hang; Skorobogatiy, Maksim

    2016-03-01

    We present a semi-analytical solution for the design of a high-speed rotary optical delay line that use a combination of two rotating curvilinear reflectors. We demonstrate that it is possible to design an infinite variety of the optical delay lines featuring linear dependence of the optical delay on the rotation angle. This is achieved via shape optimization of the rotating reflector surfaces. Moreover, a convenient spatial separation of the incoming and outgoing beams is possible. For the sake of example, we present blades that fit into a circle of 10cm diameter. Finally, a prototype of a rotary delay line is fabricated using CNC machining, and its optical properties are characterized.

  10. Systematics in delayed neutron yields

    Energy Technology Data Exchange (ETDEWEB)

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1998-03-01

    An attempt was made to reproduce the systematic trend observed in the delayed neutron yields for actinides on the basis of the five-Gaussian representation of the fission yield together with available data sets for delayed neutron emission probability. It was found that systematic decrease in DNY for heavier actinides is mainly due to decrease of fission yields of precursors in the lighter side of the light fragment region. (author)

  11. Analytical applications for delayed neutrons

    International Nuclear Information System (INIS)

    Eccleston, G.W.

    1983-01-01

    Analytical formulations that describe the time dependence of neutron populations in nuclear materials contain delayed-neutron dependent terms. These terms are important because the delayed neutrons, even though their yields in fission are small, permit control of the fission chain reaction process. Analytical applications that use delayed neutrons range from simple problems that can be solved with the point reactor kinetics equations to complex problems that can only be solved with large codes that couple fluid calculations with the neutron dynamics. Reactor safety codes, such as SIMMER, model transients of the entire reactor core using coupled space-time neutronics and comprehensive thermal-fluid dynamics. Nondestructive delayed-neutron assay instruments are designed and modeled using a three-dimensional continuous-energy Monte Carlo code. Calculations on high-burnup spent fuels and other materials that contain a mix of uranium and plutonium isotopes require accurate and complete information on the delayed-neutron periods, yields, and energy spectra. A continuing need exists for delayed-neutron parameters for all the fissioning isotopes

  12. Complications related to the use of an intraventricular access device for the treatment of leptomeningeal metastases from solid tumor: a single centre experience in 112 patients.

    Science.gov (United States)

    Zairi, Fahed; Le Rhun, Emilie; Bertrand, Nicolas; Boulanger, Thomas; Taillibert, Sophie; Aboukais, Rabih; Assaker, Richard; Chamberlain, Marc C

    2015-09-01

    Ventricular access devices (VAD) offer several advantages compared to intralumbar injections for the administration of intra-CSF agents in the treatment of leptomeningeal metastases (LM). However, there are few prospective studies reporting on complications with the use of VADs. All complications were prospectively collected that pertained to the implantation and use of a VAD in consecutive patients with solid tumor-related LM from June 2006 to December 2013. Clinical follow-up was every 2 weeks during the initial 2 months of treatment and then once monthly. Complete neuraxis MRI was performed at baseline and then every 2-3 months. A total of 112 patients (88 women) with a mean age of 51.1 years (range 26-73) were included. Primary cancers included breast (79 patients), lung (12) and melanoma (6). All patients were treated with intra-CSF liposomal cytarabine. 72 % of the patients received concomitant systemic and intra-CSF chemotherapy. The placement of the VAD was performed under local anesthesia in all cases. The mean operative time was 15 min and no perioperative complications were reported. The mean number of intraventricular injections per patient was 9.34 (range 1-47). A total of 11 complications in 11 patients were seen including 7 infections, 1 intracranial hemorrhage, 2 instances of symptomatic leukoencephalopathy and 1 catheter malpositioning. 8 complications required an operation and 1 complication was fatal. The use of a VAD is safe and may improve patients' comfort and compliance with LM-directed therapy.

  13. The Effect of Head Positioning and Head Tilting on the Incidence of Intraventricular Hemorrhage in Very Preterm Infants: A Systematic Review.

    Science.gov (United States)

    de Bijl-Marcus, Karen A; Brouwer, Annemieke J; de Vries, Linda S; van Wezel-Meijler, Gerda

    2017-01-01

    Despite advances in neonatal intensive care, germinal matrix-intraventricular hemorrhage (GMH-IVH) remains a frequent, serious complication of premature birth. Neutral head position and head tilting have been suggested to reduce the risk of GMH-IVH in preterm infants during the first 72 h of life. The aim of this study was to provide a systematic review of the effect of neutral head positioning and head tilting on the incidence of GMH-IVH in very preterm infants (gestational age ≤30 weeks). In addition, we reviewed their effect on cerebral hemodynamics and oxygenation. Literature was searched (June 2016) in the following electronic databases: CINAHL, Embase, Medline, SCOPUS, and several trial registers. One underpowered trial studied the effect of head positioning on the incidence of GMH-IVH. This randomized controlled trial enrolled 48 preterm infants and found no effect on the occurrence of GMH-IVH. Three observational studies investigated the effect of head rotation and/or tilting on cerebral oxygenation in 68 preterm infants in total. Their results suggest that cerebral oxygenation is not significantly affected by changes in head positioning. The effect of head positioning and/or tilting on cerebral hemodynamics was described in 2 observational studies of 28 preterm infants and found no significant effect. There is insufficient evidence regarding the effect of head positioning and tilting on the incidence of GMH-IVH and cerebral hemodynamics and oxygenation in preterm infants. We recommend further research in this field, especially in extremely preterm and clinically unstable infants during the first postnatal days. © 2016 S. Karger AG, Basel.

  14. Risk Factors for Intraventricular Hemorrhage in Preterm Infants Born at 34 Weeks of Gestation or Less Following Preterm Premature Rupture of Membranes.

    Science.gov (United States)

    Lu, Hongyan; Wang, Qiuxia; Lu, Junyin; Zhang, Qiang; Kumar, Pravesh

    2016-04-01

    The objective of this study is to identify possible perinatal risk factors related to intraventricular hemorrhage (IVH) in preterm infants born at 34 weeks of gestation or less following preterm premature rupture of membranes (pPROM). A total of 292 preterm infants born at 34 weeks of gestation or less following pPROM were enrolled in the study, while 155 newborns with incomplete data, especially those that lack histological examination of the placenta, maternal details, and neonatal characteristics, have been further excluded. Finally, data of 137 preterm infants were included in the analysis. All infants underwent ultrasonographic screening for IVH. Thirty-three infants with IVH were considered as cases and 104 infants without IVH were considered as controls. The association between risk factors and IVH was evaluated by univariate and multivariate logistic regression analyses. The incidence of IVH in preterm infants born at 34 weeks of gestation or less following pPROM was 24.1%, while the incidence of maternal chorioamnionitis was 43.8%. By univariate analysis, gestational age, birth weight, asphyxia resuscitation, maternal chorioamnionitis, fetal distress, amniotic fluid index, and latency of the rupture of membranes to birth were found to be significantly different between the 2 groups. By logistic regression analysis, lower gestational age, low birth weight, asphyxia resuscitation, and maternal chorioamnionitis were found to be independent risk factors for IVH. Lower gestational age, low birth weight, asphyxia resuscitation, and maternal chorioamnionitis are independent risk factors for IVH in preterm infants born at 34 weeks of gestation or less following pPROM. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  15. Delay and reward choice in ADHD: an experimental test of the role of delay aversion.

    Science.gov (United States)

    Marco, Rafaela; Miranda, Ana; Schlotz, Wolff; Melia, Amanda; Mulligan, Aisling; Müller, Ueli; Andreou, Penny; Butler, Louise; Christiansen, Hanna; Gabriels, Isabel; Medad, Sheera; Albrecht, Bjorn; Uebel, Henrik; Asherson, Phillip; Banaschewski, Tobias; Gill, Michael; Kuntsi, Jonna; Mulas, Fernando; Oades, Robert; Roeyers, Herbert; Steinhausen, Hans-Christoph; Rothenberger, Aribert; Faraone, Stephen V; Sonuga-Barke, Edmund J S

    2009-05-01

    Children with attention deficit/hyperactivity disorder (ADHD) choose smaller sooner (SS) over larger later (LL) rewards more than controls. Here we assess the contributions of impulsive drive for immediate rewards (IDIR) and delay aversion (DAv) to this pattern. We also explore the characteristics of, and the degree of familiality in, ADHD SS responders. We had 360 ADHD probands; 349 siblings and 112 controls (aged between 6 to 17 years) chose between SS (1 point after 2 s) and LL reward (2 points after 30 s) outcomes on the Maudsley Index of Delay Aversion (Kuntsi, Oosterlaan, & Stevenson, 2001): Under one condition SS choice led to less overall trial delay under another it did not. ADHD participants chose SS more than controls under both conditions. This effect was larger when SS choice reduced trial delay. ADHD SS responders were younger, had lower IQ, more conduct disorder and had siblings who were more likely to be SS responders themselves. The results support a dual component model in which both IDIR and DAv contribute to SS choice in ADHD. SS choice may be a marker of an ADHD motivational subtype.

  16. The effect of response-delay on estimating reachability.

    Science.gov (United States)

    Gabbard, Carl; Ammar, Diala

    2008-11-01

    The experiment was conducted to compare visual imagery (VI) and motor imagery (MI) reaching tasks in a response-delay paradigm designed to explore the hypothesized dissociation between vision for perception and vision for action. Although the visual systems work cooperatively in motor control, theory suggests that they operate under different temporal constraints. From this perspective, we expected that delay would affect MI but not VI because MI operates in real time and VI is postulated to be memory-driven. Following measurement of actual reach, right-handers were presented seven (imagery) targets at midline in eight conditions: MI and VI with 0-, 1-, 2-, and 4-s delays. Results indicted that delay affected the ability to estimate reachability with MI but not with VI. These results are supportive of a general distinction between vision for perception and vision for action.

  17. Evaluación de la incidencia y los factores de riesgo para hemorragia intraventricular (HIV en la cohorte de recién nacidos prematuros atendidos en la unidad neonatal del HUSVP, de Medellín, en el período comprendido entre ene. de 1999 y dic. de 2004 Incidence and risk factors of intraventricular hemorrhage in preterm newborns

    Directory of Open Access Journals (Sweden)

    Yira Sánchez Hidalgo

    2007-12-01

    Full Text Available La hemorragia intraventricular (HIV es la principal complicación neurológica de los recién nacidos prematuros, cuyas frecuencia y gravedad aumentan con el menor peso al nacer y la menor edad gestacional. Se han encontrado otros factores asociados con el aumento o disminución de su frecuencia. Objetivo: determinar la incidencia de HIV en prematuros atendidos en el Hospital Universitario San Vicente de Paúl (HUSVP, de Medellín, Colombia, entre 1999 y 2004 y establecer su asociación con condiciones de la madre y del recién nacido. Metodología: estudio retrospectivo de los prematuros menores de 32 semanas y por debajo de 1.500 gramos, atendidos en el HUSVP entre 1999 y 2004. Se calculó una muestra de 330 historias clínicas, seleccionadas en forma aleatoria, con un nivel de confianza de 95%, error del 3% y poder del 80%,con base en una incidencia del 15% de HIV en la población general. Resultados: la incidencia encontrada de HIV fue 29,8%. Como factores protectores se encontraron los siguientes: parto por cesárea, parto en un centro de tercer nivel y maduración pulmonar. Como factores que aumentaron el riesgo de HIV se encontraron: parto vaginal, edad gestacional menor de 28 semanas, uso de surfactante, ventilación mecánica, cateterismo umbilical, acidosis e hipercapnia. Conclusiones: se debe insistir en la importancia de que haya programas adecuados de control prenatal para tratar de disminuir la frecuencia de parto prematuro, procurar la remisión oportuna de las gestantes de alto riesgo a centros de referencia, estimular el uso antenatal de esteroides y el control cuidadoso de los parámetros ventilatorios en los pacientes que requieran este soporte, buscando mantener un adecuado equilibrio ácido-base en los recién nacidos. Introduction: intraventricular hemorrhage is the main neurological complication of preterm newborns. Its frequency and severity increase as gestational age and weight at birth decrease. Other factors have been

  18. O uso da fontanela posterior no diagnóstico ultra-sonográfico das hemorragias periintraventriculares Use of posterior fontanelle in the ultrasound diagnosis of intraventricular/periventricular hemorrhage

    Directory of Open Access Journals (Sweden)

    Luciana D. V. Gauzzi

    2008-12-01

    Full Text Available OBJETIVO: Avaliar o uso da fontanela posterior em recém-nascidos prematuros (OBJECTIVE: To evaluate the use of the posterior fontanelle in premature neonates (< 37 weeks with a birth weight < 1,500 g in the ultrasound diagnosis of intraventricular/periventricular hemorrhage and to assess whether the use of the anterior fontanelle associated with the posterior fontanelle changes the interrater agreement. METHODS: Eighty-five premature neonates were evaluated in this prospective study. Ultrasound was performed using the anterior fontanelle, and later, the posterior fontanelle. A consensus diagnosis between two raters was used to analyze the agreement between the anterior fontanelle alone and in association with the posterior fontanelle. If there was no consensus, a third observer was involved to decide. RESULTS: Agreement between the first two raters had a kappa of 0.80 (95%CI 0.76-0.84. However, when the anterior fontanelle was evaluated alone, kappa was 0.74 (95%CI 0.70-0.78. Thirty-seven hemispheres had grade II hemorrhage, of which 17 (45.9% had their diagnosis performed using the anterior fontanelle; in 10 (27%, diagnosis was suspected by the anterior fontanelle and confirmed by the posterior fontanelle; and in 10 (27%, diagnosis was exclusively performed using the posterior fontanelle. Of the 454 hemispheres, in 20 (4.4% the diagnosis of intraventricular hemorrhage was performed exclusively by the posterior fontanelle (p < 0.001. CONCLUSIONS: In this study, the anterior fontanelle associated with the posterior fontanelle was better than the use of the anterior fontanelle alone in the identification of intraventricular/periventricular hemorrhage. Ultrasound using the posterior fontanelle allowed diagnosis of unsuspected grade II hemorrhage by the anterior fontanelle. Use of the posterior fontanelle was also useful to clarify presence of hemorrhage in inconclusive examinations by the anterior fontanelle.

  19. Magnetic resonance imaging assessment of intraventricular dyssynchrony and delayed enhancement as predictors of response to cardiac resynchronization therapy in patients with heart failure of ischaemic and non-ischaemic etiologies

    International Nuclear Information System (INIS)

    Petryka, Joanna; Miśko, Jolanta; Przybylski, Andrzej; Śpiewak, Mateusz; Małek, Łukasz A.; Werys, Konrad; Mazurkiewicz, Łukasz; Gepner, Katarzyna; Croisille, Pierre; Demkow, Marcin; Rużyłło, Witold

    2012-01-01

    Purpose: To assess the value of dyssynchrony and myocardial viability assessment by cardiac magnetic resonance (CMR) in prediction of response to cardiac resynchronization therapy (CRT) in patients with heart failure (HF) of both ischaemic and non-ischaemic etiologies. Materials and methods: Patients scheduled for CRT in NYHA class II–IV, left ventricular ejection fraction <35%, QRS ≥ 120 ms were included. Tagged cine and late gadolinium enhancement (LGE) images were performed. Dyssynchrony was assessed with inTag toolbox and LGE was quantified using cutoff value at half of maximal signal in the scar. Cardiopulmonary exercise test, echocardiography and blood testing for NT-proBNP levels were done at baseline and 6 months after CRT. Results: 52 patients (age 60.3 ± 13 years) were included. 26 patients (50%) met response criteria. The ischaemic etiology of HF was more frequent (69% vs. 31%, p = 0.002), the percent of LGE was higher (7.7% [0–13.5%] vs. 19.0% (0–31.9%], p = 0.013), regional vector of circumferential strain variance (RVV) was lower (0.27 ± 0.08 vs. 0.34 ± 0.09, p = 0.009) and uniformity of radial strain was higher (0.72 ± 0.25 vs. 0.56 ± 0.29, p = 0.046) in non-responders vs. responders. Multivariate logistic regression showed that RVV predicted response to CRT (HR 2.3, 95% CI 1.02–5.02, p = 0.0430) independently of LGE and the etiology of heart failure. In the subgroup of patients with ischaemic HF the extend of transmural scar within myocardium was higher in non-responders vs. responders (26.3% vs. 15.0% respectively, p = 0.01) and was a predictor of response to CRT in univariable analysis (HR 0.87, 95% CI 0.77–0.98, p = 0.025) providing the sensitivity of 76% and specificity of 75% at the cutoff point of 18% in the prediction of poor response to CRT. In patients with non-ischaemic HF QRS was wider (162 ms vs. 140 ms, p = 0.04), regional vector of strain variance (RVV) was higher (0.39 vs. 0.25, p = 0.002) and uniformity of radial strain was lower (0.52 vs. 0.80, p = 0.049) in non-responders vs. responders. Univariable logistic regression showed that RVV was a predictor of response to CRT (HR 1.50, 95% CI 1.06–2.13, p = 0.022), providing the sensitivity of 94% and specificity of 85% at the cutoff point of 0.31. Conclusions: CMR derived parameters of dyssynchrony such as RVV may provide an additive value in prediction of response to CRT, especially in patients with non-ischaemic etiology of heart failure. In patients with ischaemic HF the transmurality of LGE is an important predictor of lack of response to CRT

  20. Magnetic resonance imaging assessment of intraventricular dyssynchrony and delayed enhancement as predictors of response to cardiac resynchronization therapy in patients with heart failure of ischaemic and non-ischaemic etiologies

    Energy Technology Data Exchange (ETDEWEB)

    Petryka, Joanna, E-mail: joannapetryka@hotmail.com [Department of Coronary Artery Disease and Structural Heart Diseases, Institute of Cardiology, Warsaw (Poland); Cardiovascular Magnetic Resonance Unit, Institute of Cardiology, Warsaw (Poland); Miśko, Jolanta [Cardiovascular Magnetic Resonance Unit, Institute of Cardiology, Warsaw (Poland); Department of Radiology, Institute of Cardiology, Warsaw (Poland); Przybylski, Andrzej [Department of Arrhythmia, Institute of Cardiology, Warsaw (Poland); Śpiewak, Mateusz [Department of Coronary Artery Disease and Structural Heart Diseases, Institute of Cardiology, Warsaw (Poland); Cardiovascular Magnetic Resonance Unit, Institute of Cardiology, Warsaw (Poland); Małek, Łukasz A. [Cardiovascular Magnetic Resonance Unit, Institute of Cardiology, Warsaw (Poland); Department of Cardiology and Interventional Angiology, Institute of Cardiology, Warsaw (Poland); Werys, Konrad [Cardiovascular Magnetic Resonance Unit, Institute of Cardiology, Warsaw (Poland); Mazurkiewicz, Łukasz [Cardiovascular Magnetic Resonance Unit, Institute of Cardiology, Warsaw (Poland); Department of Cardiomyopathy, Institute of Cardiology, Warsaw (Poland); Gepner, Katarzyna [Department of Coronary Artery Disease, Institute of Cardiology, Warsaw (Poland); Croisille, Pierre [Creatis Laboratory, UMR CNRS 5515, INSERM, U1044, CHU Saint-Etienne, Universite de Lyon (France); Demkow, Marcin [Department of Coronary Artery Disease and Structural Heart Diseases, Institute of Cardiology, Warsaw (Poland); Rużyłło, Witold [Institute of Cardiology, Warsaw (Poland)

    2012-10-15

    Purpose: To assess the value of dyssynchrony and myocardial viability assessment by cardiac magnetic resonance (CMR) in prediction of response to cardiac resynchronization therapy (CRT) in patients with heart failure (HF) of both ischaemic and non-ischaemic etiologies. Materials and methods: Patients scheduled for CRT in NYHA class II–IV, left ventricular ejection fraction <35%, QRS ≥ 120 ms were included. Tagged cine and late gadolinium enhancement (LGE) images were performed. Dyssynchrony was assessed with inTag toolbox and LGE was quantified using cutoff value at half of maximal signal in the scar. Cardiopulmonary exercise test, echocardiography and blood testing for NT-proBNP levels were done at baseline and 6 months after CRT. Results: 52 patients (age 60.3 ± 13 years) were included. 26 patients (50%) met response criteria. The ischaemic etiology of HF was more frequent (69% vs. 31%, p = 0.002), the percent of LGE was higher (7.7% [0–13.5%] vs. 19.0% (0–31.9%], p = 0.013), regional vector of circumferential strain variance (RVV) was lower (0.27 ± 0.08 vs. 0.34 ± 0.09, p = 0.009) and uniformity of radial strain was higher (0.72 ± 0.25 vs. 0.56 ± 0.29, p = 0.046) in non-responders vs. responders. Multivariate logistic regression showed that RVV predicted response to CRT (HR 2.3, 95% CI 1.02–5.02, p = 0.0430) independently of LGE and the etiology of heart failure. In the subgroup of patients with ischaemic HF the extend of transmural scar within myocardium was higher in non-responders vs. responders (26.3% vs. 15.0% respectively, p = 0.01) and was a predictor of response to CRT in univariable analysis (HR 0.87, 95% CI 0.77–0.98, p = 0.025) providing the sensitivity of 76% and specificity of 75% at the cutoff point of 18% in the prediction of poor response to CRT. In patients with non-ischaemic HF QRS was wider (162 ms vs. 140 ms, p = 0.04), regional vector of strain variance (RVV) was higher (0.39 vs. 0.25, p = 0.002) and uniformity of radial strain was lower (0.52 vs. 0.80, p = 0.049) in non-responders vs. responders. Univariable logistic regression showed that RVV was a predictor of response to CRT (HR 1.50, 95% CI 1.06–2.13, p = 0.022), providing the sensitivity of 94% and specificity of 85% at the cutoff point of 0.31. Conclusions: CMR derived parameters of dyssynchrony such as RVV may provide an additive value in prediction of response to CRT, especially in patients with non-ischaemic etiology of heart failure. In patients with ischaemic HF the transmurality of LGE is an important predictor of lack of response to CRT.

  1. Fundamentals of Delayed Coking Joint Industry Project

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk Jr; Keith Wisecarver

    2005-10-01

    is 2,937,439 barrels/calendar day. These cokers produce 154,607 tons of coke per day and delayed coking accounts for 88% of the world capacity. The delayed coking charge capacity in the United States is 1,787,860 b/cd. Despite its wide commercial use, only relatively few contractors and refiners are truly knowledgeable in delayed-coking design, so that this process carries with it a ''black art'' connotation. Until recently, the expected yield from cokers was determined by a simple laboratory test on the feedstock. As a result of Tulsa University's prior related research, a process model was developed that with additional work could be used to optimize existing delayed cokers over a wide range of potential feedstocks and operating conditions. The objectives of this research program are to: utilize the current micro, batch and pilot unit facilities at The University of Tulsa to enhance the understanding of the coking process; conduct additional micro and pilot unit tests with new and in-house resids and recycles to make current optimization models more robust; conduct focused kinetic experiments to enhance the furnace tube model and to enhance liquid production while minimizing sulfur in the products; conduct detailed foaming studies to optimize the process and minimize process upsets; quantify the parameters that affect coke morphology; and to utilize the knowledge gained from the experimental and modeling studies to enhance the computer programs developed in the previous JIP for optimization of the coking process. These refined computer models will then be tested against refinery data provided by the member companies. Novel concepts will also be explored for hydrogen sulfide removal of furnace gases as well as gas injection studies to reduce over-cracking. The following deliverables are scheduled from the two projects of the three-year JIP: (1) A novel method for enhancing liquid yields from delayed cokers and data that provide insight as to

  2. UWB delay and multiply receiver

    Energy Technology Data Exchange (ETDEWEB)

    Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.

    2013-09-10

    An ultra-wideband (UWB) delay and multiply receiver is formed of a receive antenna; a variable gain attenuator connected to the receive antenna; a signal splitter connected to the variable gain attenuator; a multiplier having one input connected to an undelayed signal from the signal splitter and another input connected to a delayed signal from the signal splitter, the delay between the splitter signals being equal to the spacing between pulses from a transmitter whose pulses are being received by the receive antenna; a peak detection circuit connected to the output of the multiplier and connected to the variable gain attenuator to control the variable gain attenuator to maintain a constant amplitude output from the multiplier; and a digital output circuit connected to the output of the multiplier.

  3. Chaos in the delay logistic equation with discontinuous delays

    International Nuclear Information System (INIS)

    Sen, Ayan; Mukherjee, Debasis

    2009-01-01

    This paper analyzes a delay logistic equation which models a feedback control problem. Interval map associated to the system is derived. By calculating Lyapunov exponent, we indicate stable orbit and chaotic phenomenon respectively. The results are verified through computer simulation. We identify the parameter which controls the dynamics.

  4. Postraumatic delayed loss of vision

    International Nuclear Information System (INIS)

    Partington, C.R.; Graves, V.B.; Ruetenacht, D.A.; Weinstein, J.M.; Strother, C.M.

    1989-01-01

    The imaging studies and clinical findings in 10 patients who suffered delayed vision loss beginning 1 day to 13 years after head trauma have been reviewed. Two different primary lesions could be identified: pseudoaneurysm of the internal carotid artery and carotid cavernous fistula. The pathologic changes associated with pseudoaneurysm included compression of the optic nerves and/or chiasm by arterial aneurysm and intracranial hematoma. Carotid cavernous fistula caused delayed vision loss by compression of the optic nerves and chiasm by saccular dilatation of the cavernous sinus and by abnormal orbital venous drainage with retinal venous stasis, retinal edema, and glaucoma

  5. Time delayed Ensemble Nudging Method

    Science.gov (United States)

    An, Zhe; Abarbanel, Henry

    Optimal nudging method based on time delayed embedding theory has shows potentials on analyzing and data assimilation in previous literatures. To extend the application and promote the practical implementation, new nudging assimilation method based on the time delayed embedding space is presented and the connection with other standard assimilation methods are studied. Results shows the incorporating information from the time series of data can reduce the sufficient observation needed to preserve the quality of numerical prediction, making it a potential alternative in the field of data assimilation of large geophysical models.

  6. 49 CFR 236.563 - Delay time.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Delay time. 236.563 Section 236.563 Transportation... Cab Signal Systems Rules and Instructions; Locomotives § 236.563 Delay time. Delay time of automatic... requirements of § 236.24 shall take into consideration the delay time. ...

  7. Diphenylhydantoin and lidocaine modification of A-V conduction in halothane-anesthetized dogs.

    Science.gov (United States)

    Atlee, J L; Homer, L D; Tobey, R E

    1975-07-01

    The effect of halothane on A-V conduction was evaluated in gods during atrial pacing using the technique of His-bundle electrocardiography. In addition, the effects of lidocaine and diphenylkydantoin (DPH) on A-V conuction were examined during halothane anesthesia. Effects of these drugs on three subintervals of A-V conduction were compared. These included the -H (stimulus atifact of His-bundle deflection-atrioventricular conduction), H-Q (His-budnle deflection onset of QRS complex-His-Purkinje conduction), and H-S intervals(His-bundle delfection to end of QRS COmplex-total intraventricular conduction). Linear regression best described the relationship between duration of interval (P-H, H-V,and H-S) and heart rate during incremental increases in the atrial paced rate. Data from these experiments were fitted to a multiple lenear regression model that predicted the effect of increasing concentrations of halothan, lidocaine, and DPH on slope and intercept coefficients. In creasing concentrations of halothan ( 30 and 45 mg/100 ml arterial). Both lidocaine and DPH further depressed conduction at all levels of halothan anesthesia. The P-H interval was particularly sensitive todrug effefts. This may represent potentiation of the normal slowing of conduction through the AVnode in response to incremental increases in heart rate (fatigue response.) We conclude thatboth lidocaine and DPH fail to reverse the depressant effect of halothane on A-V conduction. This may explain their ineffectiveness in treating certain types of arrhythmias during halothane anesthesia.

  8. Dose-related ethanol intake, Cx43 and Nav1.5 remodeling: Exploring insights of altered ventricular conduction and QRS fragmentation in excessive alcohol users.

    Science.gov (United States)

    Hung, Chung-Lieh; Lai, Yu-Jun; Chi, Po-Ching; Chen, Liang-Chia; Tseng, Ya-Ming; Kuo, Jen-Yuan; Lin, Cheng-I; Chen, Yao-Chang; Lin, Shing-Jong; Yeh, Hung-I

    2018-01-01

    Chronic, excessive ethanol intake has been linked with various electrical instabilities, conduction disturbances, and even sudden cardiac death, but the underlying cause for the latter is insufficiently delineated. We studied surface electrocardiography (ECG) in a community-dwelling cohort with moderate-to-heavy daily alcohol intake (grouped as >90g/day, ≤90g/day, and nonintake). Compared with nonintake, heavier alcohol users showed markedly widened QRS duration and higher prevalence of QRS fragmentation (64.3%, 50.9%, and 33.7%, respectively, χ 2 12.0, both pchronically given a 4% or 6% alcohol diet and showed dose-related slower action potential upstroke, reduced resting membrane potential, and disorganized or decreased intraventricular conduction (all pChronic excessive alcohol ingestion is associated with dose-related phenotypic intraventricular conduction disturbances and QRS fragmentation that can be recapitulated in mice. The mechanisms may involve suppressed gap junction and sodium channel functions, together with enhanced cardiac fibrosis that may contribute to arrhythmogenesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. [Factors linked to delayed diagnosis of tuberculosis in Conakry (Guinea)].

    Science.gov (United States)

    Camara, A; Diallo, A; Camara, L M; Fielding, K; Sow, O Y; Chaperon, J

    2006-03-01

    Untreated smear-positive pulmonary tuberculosis constitutes a reservoir of infection which is highly contagious. The present study was conducted in Conakry, Guinea, to determine the different options which are available when seeking treatment or care, and to ascertain the average delay in diagnosis of pulmonary tuberculosis and the main factors linked to the delay in diagnosis after the initial onset of symptoms. Through a cross-sectional study, 113 consecutive patients with smear-positive pulmonary tuberculosis were interviewed through the use of a questionnaire. The median total delay from the onset of symptoms of pulmonary tuberculosis until the diagnosis was 11 weeks. This delay period exceeded 4 weeks for 90 of the patients (80%). The average delay linked to the conventional health care system was double that of the one at the fault of the patient (6 weeks versus 3 weeks, respectively). 54% of the patients had initially resorted to non-conventional care. To shorten this mean delay period, it is necessary to both strengthen the professional abilities and skills which train for one to better to detect tuberculosis and to sensitize the population to the subject matter and information on the illness and its symptoms.

  10. Early-delayed radiation rhombencephalopathy

    International Nuclear Information System (INIS)

    Nightingale, S.; Dawes, P.J.D.K.; Cartlidge, N.E.F.; Newcastle upon Tyne Univ.

    1982-01-01

    A 37-year-old woman developed an early-delayed rhombencephalopathy 7 weeks after completing a course of radiotherapy to a glomus jugulare tumour. The clinical features, comprising nystagmus, skew strabismus, unilateral facial weakness, dysarthria and ataxia, are compared with four previously reported patients with this syndrome. (author)

  11. Another definition for time delay

    International Nuclear Information System (INIS)

    Narnhofer, H.

    1980-01-01

    Time delay is defined by geometrical considerations which work in classical as well as in quantum mechanics, and its connection with the S-matrix and the virial is proven for potentials with V(x vector) and x vector V(x vector) vanishing as rsup(-1-epsilon) for r -> infinity. (Author)

  12. Weather delay costs to trucking.

    Science.gov (United States)

    2012-11-01

    Estimates of the nations freight sector of transportation range to upwards of $600 billion of total gross domestic product with 70 percent of total value and 60 percent of total weight moving by truck. Weather-related delays can add significantly ...

  13. Diagnostic Delay in Rheumatoid Arthritis

    DEFF Research Database (Denmark)

    Mølbaek, Karen; Hørslev-Petersen, Kim; Primdahl, Jette

    2016-01-01

    BACKGROUND: To prevent joint damage among patients with rheumatoid arthritis (RA), there is a need to minimize delays from the onset of symptoms until the initiation of appropriate therapy. The present study explored the factors that have an impact on the time it takes for Danish patients with RA...

  14. Design flaw could delay collider

    CERN Multimedia

    Cho, Adrian

    2007-01-01

    "A magnet for the Large Hadron Collider (LHC) failed during a key test at the European particle physics laboratory CERN last week. Physicists and engineers will have to repair the damaged magnet and retrofit others to correct the underlynig design flaw, which could delay the start-up of the mammouth subterranean machine." (1,5 page)

  15. Concurrent Delay in Construction Disputes

    DEFF Research Database (Denmark)

    Cavaleri, Sylvie Cécile

    the delay is contractually defined as a contractor's risk, the contractor is liable to pay liquidated damages to the employer; if it is not, the contractor can under certain circumstances claim an extension of time and in some cases also economic compensation from the employer. The situation where a given...

  16. Deconstructing delayed posttraumatic stress disorder

    NARCIS (Netherlands)

    Smid, G

    2011-01-01

    According to the Diagnostic and Statistical Manual of Mental Disorders, delayed posttraumatic stress disorder (PTSD) must be diagnosed in individuals fulfilling criteria for PTSD if the onset of symptoms is at least six months after the trauma. The purpose of this thesis was to establish the

  17. Livermore blasted for project delay

    CERN Multimedia

    1999-01-01

    In a 12 page report issued last week, a review committee set up by the University of California has concluded that mismanagement and poor planning are to blame for significant cost overruns and delays in the construction of NIF, the worlds largest laser (1 page).

  18. Providing delay guarantees in Bluetooth

    NARCIS (Netherlands)

    Ait Yaiz, R.; Heijenk, Geert; Titsworth, F.

    2003-01-01

    Bluetooth polling, also referred to as Bluetooth MAC scheduling or intra-piconet scheduling, is the mechanism that schedules the traffic between the participants in a Bluetooth network. Hence, this mechanism is highly determining with respect to the delay packets experience in a Bluetooth network.

  19. A new dimension to EU pharma antitrust product hopping and unilateral pay for delay

    OpenAIRE

    Gallasch, Sven

    2016-01-01

    Pay for delay settlements are currently high on the competition law enforcement agenda. The focus in these investigations is on the collusive nature of the agreements between a brand company and generic companies. However, this article moves the discussion away from the commonly recognized collusive anticompetitive potential, advocating for the expansion of antitrust scrutiny of pay for delay settlements to unilateral conduct. Pay for delay settlements could be used as a “facilitator” for a b...

  20. Analysis of a first-order delay differential-delay equation containing two delays

    Science.gov (United States)

    Marriott, C.; Vallée, R.; Delisle, C.

    1989-09-01

    An experimental and numerical analysis of the behavior of a two-delay differential equation is presented. It is shown that much of the system's behavior can be related to the stability behavior of the underlying linearized modes. A new phenomenon, mode crossing, is explored.

  1. Temperature dependence of nonsteady radiation conductivity of polymers

    International Nuclear Information System (INIS)

    Tyutnev, A.P.; Saenko, V.S.; Dunaev, A.F.; Sichkar', V.P.; Vannikov, A.V.

    1984-01-01

    Influence of temperature on non-steady radiation conductivity (NRC) of polymeric dielectrics is investigated. It is revealed that the temperature effects first of all delayed NRC constituent. Temperature increase up to 100 deg C is followed by certain slowing down the rate of current drop of induced conductivity, in this case the nature of the volt-ampere characteristic of delayed NRC constituent does not essentially change, as a rule. The obtained experimental results interpreted in the frames of the band model permitted to make conclusions on the effect of chemical structure of the polymer on its NRC. Presence of carbazole or phenylic groups in the elementary chain is shown to increase the delayed constituent of induced conductivity and to ensure prevailing yield of free charges. Appearance of methyl groups in the composition of the chain essentially suppresses the delayed constituent and results in high values of activation energy and rather slowed down current drop

  2. THE PREVALENCE OF INTRAVENTRICULAR HAEMORRHAGE

    African Journals Online (AJOL)

    Esem

    haemorrhage in preterm infants with birth weight 1.5kg and less was 34.2% in ... case fatality rate was 85.7% for those with grade 4 in the first three days of life. ... with case fatality rates of more than 45% (2007 and 2008 NICU ward statistics).

  3. Relations between Self Regulation, Future Time Perspective and the Delay of Gratification in University Students

    Science.gov (United States)

    Avci, Suleyman

    2013-01-01

    The present study was conducted on 508 (331 female, 144 male) first grade university students in order to investigate the relations between self regulation, the future time perspectives, and the delay of gratification in the academic field. A future time perspective scale, an academic delay of gratification scale and a motivational strategies for…

  4. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong

    2017-11-09

    We present a general framework and method for detection of an object in a video based on apparent motion. The object moves relative to background motion at some unknown time in the video, and the goal is to detect and segment the object as soon it moves in an online manner. Due to unreliability of motion between frames, more than two frames are needed to reliably detect the object. Our method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  5. Depressive illness delayed Hamlet's revenge.

    Science.gov (United States)

    Shaw, A B; Pickering, Neil

    2002-12-01

    If Hamlet had not delayed his revenge there would have been no play. Many explanations of the delay have been offered in the last four centuries. None is convincing. The interpretation which best fits the evidence best is that Hamlet was suffering from an acute depressive illness, with some obsessional features. He could not make a firm resolve to act. In Shakespeare's time there was no concept of acute depressive illness, although melancholy was well known. Melancholy, however, would have been seen as a character defect. In the tragic model the hero brings himself and others to ruin because of a character defect. Thus, at the time, the play conformed to the tragic model. With today's knowledge, it does not. This analysis adds to, but does not replace, other insights into the play.

  6. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong

    2017-01-08

    We present a general framework and method for detection of an object in a video based on apparent motion. The object moves relative to background motion at some unknown time in the video, and the goal is to detect and segment the object as soon it moves in an online manner. Due to unreliability of motion between frames, more than two frames are needed to reliably detect the object. Our method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  7. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong; Sundaramoorthi, Ganesh

    2017-01-01

    We present a general framework and method for detection of an object in a video based on apparent motion. The object moves relative to background motion at some unknown time in the video, and the goal is to detect and segment the object as soon it moves in an online manner. Due to unreliability of motion between frames, more than two frames are needed to reliably detect the object. Our method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  8. Teriparatide Induced Delayed Persistent Hypercalcemia

    Directory of Open Access Journals (Sweden)

    Nirosshan Thiruchelvam

    2014-01-01

    Full Text Available Teriparatide, a recombinant PTH, is an anabolic treatment for osteoporosis that increases bone density. Transient hypercalcemia is a reported side effect of teriparatide that is seen few hours following administration of teriparatide and resolves usually within 16 hours of drug administration. Persistent hypercalcemia, although not observed in clinical trials, is rarely reported. The current case describes a rare complication of teriparatide induced delayed persistent hypercalcemia.

  9. Assembly delay line pulse generators

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    Assembly of six of the ten delay line pulse generators that will power the ten kicker magnet modules. One modulator part contains two pulse generators. Capacitors, inductances, and voltage dividers are in the oil tank on the left. Triggered high-pressure spark gap switches are on the platforms on the right. High voltage pulse cables to the kicker magnet emerge under the spark gaps. In the centre background are the assembled master gaps.

  10. Minimum Delay Moving Object Detection

    KAUST Repository

    Lao, Dong

    2017-05-14

    This thesis presents a general framework and method for detection of an object in a video based on apparent motion. The object moves, at some unknown time, differently than the “background” motion, which can be induced from camera motion. The goal of proposed method is to detect and segment the object as soon it moves in an online manner. Since motion estimation can be unreliable between frames, more than two frames are needed to reliably detect the object. Observing more frames before declaring a detection may lead to a more accurate detection and segmentation, since more motion may be observed leading to a stronger motion cue. However, this leads to greater delay. The proposed method is designed to detect the object(s) with minimum delay, i.e., frames after the object moves, constraining the false alarms, defined as declarations of detection before the object moves or incorrect or inaccurate segmentation at the detection time. Experiments on a new extensive dataset for moving object detection show that our method achieves less delay for all false alarm constraints than existing state-of-the-art.

  11. Development of delayed radiation necrosis

    International Nuclear Information System (INIS)

    Ohara, ShigFeki; Takagi, Terumasa; Shibata, Taichiro; Nagai, Hajime.

    1983-01-01

    The authors discussed the developing process of delayed radiation necrosis of the brain from the case of a 42-year-old female who developed intracranial hypertension and left hemiparesis 5 and a half years after radiotherapy for pituitary adenoma. The initial sign of radiation necrosis was from a CT scan taken 3 and a half years after radiotherapy showing an irregular low density lesion in the right temporal lobe. CT scan 2 years later demonstrated displacement of the midline structures to the left and a larger low density lesion with partially high density in the right MCA territory that was enhanced with intravenous contrast medium. Recovery after a right temporal lobectomy and administration of steroid hormone were uneventful. Eight months later there were no signs of raised intracranial pressure nor of neurological deficits. Tissues obtained from the right temporal lobe at lobectomy revealed the characteristic changes of delayed radiation necrosis; a mixture of fresh, recent, and old vascular lesions in the same specimen. From these findings, it was speculated that delayed radiation necrosis might initially occur within several years after radiotherapy and might gradually take a progressive and extended course, even in cases whose clinical symptoms develop much later. (author)

  12. Multidimensional Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of multidimensional heat conduction. General heat conduction equation in three dimensions. Steay state, analytical solutions. The Laplace equation. Method of separation of variables. Principle of superposition. Shape factors. Transient, multidimensional heat conduction....

  13. Added value of delayed computed tomography angiography in primary intracranial hemorrhage and hematoma size for predicting spot sign.

    Science.gov (United States)

    Wu, Te Chang; Chen, Tai Yuan; Shiue, Yow Ling; Chen, Jeon Hor; Hsieh, Tsyh-Jyi; Ko, Ching Chung; Lin, Ching Po

    2018-04-01

    Background The computed tomography angiography (CTA) spot sign represents active contrast extravasation within acute primary intracerebral hemorrhage (ICH) and is an independent predictor of hematoma expansion (HE) and poor clinical outcomes. The spot sign could be detected on first-pass CTA (fpCTA) or delayed CTA (dCTA). Purpose To investigate the additional benefits of dCTA spot sign in primary ICH and hematoma size for predicting spot sign. Material and Methods This is a retrospective study of 100 patients who underwent non-contrast CT (NCCT) and CTA within 24 h of onset of primary ICH. The presence of spot sign on fpCTA or dCTA, and hematoma size on NCCT were recorded. The spot sign on fpCTA or dCTA for predicting significant HE, in-hospital mortality, and poor clinical outcomes (mRS ≥ 4) are calculated. The hematoma size for prediction of CTA spot sign was also analyzed. Results Only the spot sign on dCTA could predict high risk of significant HE and poor clinical outcomes as on fpCTA ( P spot sign on fpCTA or dCTA in the absence of intraventricular and subarachnoid hemorrhage. Conclusion This study clarifies that dCTA imaging could improve predictive performance of CTA in primary ICH. Furthermore, the XY value is the best predictor for CTA spot sign.

  14. Delayed Hospital Discharges of Older Patients: A Systematic Review on Prevalence and Costs.

    Science.gov (United States)

    Landeiro, Filipa; Roberts, Kenny; Gray, Alastair Mcintosh; Leal, José

    2017-05-23

    To determine the prevalence of delayed discharges of elderly inpatients and associated costs. We searched Medline, Embase, Global Health, CAB Abstracts, Econlit, Web of Knowledge, EBSCO - CINAHL, The Cochrane Library, Health Management Information Consortium, and SCIE - Social Care Online for evidence published between 1990 and 2015 on number of days or proportion of delayed discharges for elderly inpatients in acute hospitals. Descriptive and regression analyses were conducted. Data on proportions of delayed discharges were pooled using a random effects logistic model and the association of relevant factors was assessed. Mean costs of delayed discharge were calculated in USD adjusted for Purchasing Power Parity (PPP). Of 64 studies included, 52 (81.3%) reported delayed discharges as proportions of total hospital stay and 9 (14.1%) estimated the respective costs for these delays. Proportions of delayed discharges varied widely, from 1.6% to 91.3% with a weighted mean of 22.8%. This variation was also seen in studies from the same country, for example, in the United Kingdom, they ranged between 1.6% and 60.0%. No factor was found to be significantly associated with delays. The mean costs of delayed discharge also varied widely (between 142 and 31,935 USD PPP adjusted), reflecting the variability in mean days of delay per patient. Delayed discharges occur in most countries and the associated costs are significant. However, the variability in prevalence of delayed discharges and available data on costs limit our knowledge of the full impact of delayed discharges. A standardization of methods is necessary to allow comparisons to be made, and additional studies are required-preferably by disease area-to determine the postdischarge needs of specific patient groups and the estimated costs of delays. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Synchronization in networks with heterogeneous coupling delays

    Science.gov (United States)

    Otto, Andreas; Radons, Günter; Bachrathy, Dániel; Orosz, Gábor

    2018-01-01

    Synchronization in networks of identical oscillators with heterogeneous coupling delays is studied. A decomposition of the network dynamics is obtained by block diagonalizing a newly introduced adjacency lag operator which contains the topology of the network as well as the corresponding coupling delays. This generalizes the master stability function approach, which was developed for homogenous delays. As a result the network dynamics can be analyzed by delay differential equations with distributed delay, where different delay distributions emerge for different network modes. Frequency domain methods are used for the stability analysis of synchronized equilibria and synchronized periodic orbits. As an example, the synchronization behavior in a system of delay-coupled Hodgkin-Huxley neurons is investigated. It is shown that the parameter regions where synchronized periodic spiking is unstable expand when increasing the delay heterogeneity.

  16. The economic effect and outcome of delaying oral food challenges.

    Science.gov (United States)

    Couch, Christopher; Franxman, Tim; Greenhawt, Matthew

    2016-05-01

    Food specific IgE (sIgE) is a useful marker to assess predictability of oral food challenge (OFC) outcome. A threshold of less than 2 kUA/L for peanut, egg, and milk has been proposed as a 50% negative predictive value at which patients may pass an OFC. To assess the economic effect and outcome of delaying OFCs. A retrospective analysis was performed for peanut, egg, and milk OFCs conducted between 2001 and 2012 at a tertiary food allergy referral center. Delayed OFC was defined as greater than 12 months from the time the sIgE level became less than 2 kUA/L. Time to OFC was explored in association with skin prick test result (wheal size), OFC outcome, and the economic effect of delay. Of 319 challenges, 173 OFCs were delayed (54.2%) by a mean time of 35.5 months (range, 13-123 months) vs a mean time of 4.2 months in the 146 challenges that were not delayed (P care system. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  17. Risk-factors for surgical delay following hip fracture.

    Science.gov (United States)

    Sanz-Reig, J; Salvador Marín, J; Ferrández Martínez, J; Orozco Beltrán, D; Martínez López, J F

    To identify pre-operative risk factors for surgical delay of more than 2 days after admission in patients older than 65 years with a hip fracture. A prospective observational study was conducted on 180 hip fractures in patients older than 65 years of age admitted to our hospital from January 2015 to April 2016. The data recorded included, patient demographics, day of admission, pre-fracture comorbidities, mental state, level of mobility and physical function, type of fracture, antiaggregant and anticoagulant medication, pre-operative haemoglobin value, type of treatment, and surgical delay. The mean age of the patients was 83.7 years. The mean Charlson Index was 2.8. The pre-fracture baseline co-morbidities were equal or greater than 2 in 70% of cases. Mean timing of surgery was 3.1 days. At the time of admission, 122 (67.7%) patients were fit for surgery, of which 80 (44.4%) underwent surgery within 2 days. A Charlson index greater than 2, anticoagulant therapy, and admission on Thursday to Saturday, were independently associated with a surgical delay greater than 2 days. The rate of hip fracture patients undergoing surgery within 2 days is low. Risk factors associated to surgical delay are non-modifiable. However, their knowledge should allow the development of protocols that can reduce surgical delay in this group of patients. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Synchronization analysis of coloured delayed networks under ...

    Indian Academy of Sciences (India)

    This paper investigates synchronization of coloured delayed networks under decentralized pinning intermittent control. To begin with, the time delays are taken into account in the coloured networks. In addition, we propose a decentralized pinning intermittent control for coloured delayed networks, which is different from that ...

  19. A simulation study of the effects of communication delay on air traffic control

    Science.gov (United States)

    1990-09-01

    This study was conducted to examine the impacts of voice communications delays : characteristic of Voice Switching and Control System (VSCS) and satellite : communications systems on air traffic system performance, controller stress : and workload, a...

  20. Conducting compositions of matter

    Science.gov (United States)

    Viswanathan, Tito (Inventor)

    2000-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  1. Perceived Discrimination and Reported Delay of Pharmacy Prescriptions and Medical Tests

    Science.gov (United States)

    Van Houtven, Courtney Harold; Voils, Corrine I; Oddone, Eugene Z; Weinfurt, Kevin P; Friedman, Joëlle Y; Schulman, Kevin A; Bosworth, Hayden B

    2005-01-01

    BACKGROUND Access to health care varies according to a person's race and ethnicity. Delaying treatment is one measure of access with important health consequences. OBJECTIVE Determine whether perceptions of unfair treatment because of race or ethnicity are associated with reported treatment delays, controlling for economic constraints, self-reported health, depression, and demographics. DESIGN Cross-sectional, observational study. PARTICIPANTS A randomly selected community sample of 181 blacks, 148 Latinos, and 193 whites in Durham County, NC. MEASUREMENTS A phone survey conducted in 2002 to assess discrimination, trust in medical care, quality of care, and access to care. Treatment delays were measured by whether or not a person reported delaying or forgoing filling a prescription and delaying or forgoing having a medical test/treatment in the past 12 months. Perceived discrimination was measured as unfair treatment in health care and as racism in local health care institutions. RESULTS The odds of delaying filling prescriptions were significantly higher (odds ratio (OR)=2.02) for persons who perceived unfair treatment, whereas the odds of delaying tests or treatments were significantly higher (OR=2.42) for persons who thought racism was a problem in health care locally. People with self-reported depression and people who reported not working had greater odds of delaying both types of care. CONCLUSIONS A prospective cohort study with both personal and macro measures of discrimination, as well as more refined measures of treatment delays, would help us better understand the relationship between perceived discrimination and treatment delays. PMID:16050850

  2. Delay in Presentation, Diagnosis, and Treatment for Breast Cancer Patients in Jordan.

    Science.gov (United States)

    Abu-Helalah, Ahmad Munir; Alshraideh, Hussam Ahmad; Al-Hanaqtah, Mo'tasem; Da'na, Moh'd; Al-Omari, Asim; Mubaidin, Rasmi

    2016-01-01

    Breast cancer is the most common cancer, and one of the leading causes of death for females in Jordan and many countries in the world. Studies have shown that delay in symptoms presentation, diagnosis or treatment would result in poor prognosis. There has been no published study from Jordan on delays in patient presentation, delays in diagnosis, or delays in treatment. Therefore, we conducted this study to assess these important quality indicators aiming to improve prognosis for breast cancer patients in Jordan. This project was a cross-sectional study on female breast cancer patients in Jordan. The total number of participants was 327. The proportion of patients with presentation delay, diagnosis delay, and treatment delay was 32.2%, 49.1%, or 32.4%, respectively. The main reported reasons for delay in presentation were ignorance of the nature of the problem (65.6%), limited/lack of knowledge that symptoms were suggestive of cancer diagnosis (16.7%), and misdiagnosis (16.7%). Predictors of delay and mean time for presentation, diagnosis, and treatment were identified. Our results reveal that breast cancer patients in Jordan are experiencing delays in presentation, diagnosis, and treatment. This could justify the advanced stages at diagnosis and poor outcomes for breast cancer patients in Jordan. We recommend revising the current early detection and down-staging programs in Jordan. © 2015 Wiley Periodicals, Inc.

  3. Treatment delay among pulmonary tuberculosis patients in pastoralist communities in Bale Zone, Southeast Ethiopia

    Directory of Open Access Journals (Sweden)

    Hussen Awol

    2012-06-01

    Full Text Available Abstract Background Tuberculosis (TB is a major public health problem in Africa with Ethiopia being the most affected. Treatment delay is an important indicator of access to TB diagnosis and treatment. However, little is known about factors associated with treatment delay of pulmonary TB among pastoralists. Health facility based cross sectional study was conducted on 129 pulmonary TB patients in pastoralist community. The study was conducted in three health centers and a hospital. Time between onset of TB symptoms and first visit to a professional health care provider (patient delay, and the time between first visits to the professional health care provider to the date of diagnosis (provider's delay were analyzed using SPSS 16.0 statistical software. Findings A total of 129 new smear positive pulmonary TB patients participated in the study. The median total delay was 97 days. The median patient and health provider delays were 63 and 34 days, respectively. Ninety six percent of the patients were delayed for more than the twenty one days cutoff point. Patient delay was positively associated with first visit to traditional healer/private clinic/drug shop, rural residence, being illiterate, living in more than 10 kilometers from health facility; severity of illness at first presentation to health facility. Provider delay was positively associated with rural residence, being illiterate, patient with good functional status, patients in contact with more than two health providers, and place of first visit being traditional healer/private clinic/drug shop. Conclusions This study showed that majority of smear positive patients delayed either for diagnosis or treatment, thus continue to serve as reservoirs of infection. This indicates that there is a need for intervention to decrease patient and provider delays. Effort to reduce delays in pastoralist communities should focus on improving access to services in rural communities, engaging traditional and

  4. Delayed healing of lower limb fractures with bisphosphonate therapy.

    Science.gov (United States)

    Yue, B; Ng, A; Tang, H; Joseph, S; Richardson, M

    2015-07-01

    Bisphosphonate therapy (BT) is used commonly in the management of osteoporosis. A systematic review was conducted investigating delayed union of lower limb, long bone fractures in patients on BT. We specifically assessed whether BT increases the risk of delayed union or non-union in lower limb, long bone fractures. A literature search was conducted in the PubMed and Embase™ on 4 November 2014. Articles that investigated lower limb fractures, history of BT and fracture union were included in the review. A total of 9,809 papers were retrieved and 14 were deemed suitable for this review. The mean time to union in patients on BT was 8.5 months. A longer time to union was reported in a study investigating BT users versus controls (6.5 vs 4.8 months respectively). The mean rate of delayed or non-union for BT associated atypical fractures was 20% per fracture. Specifically in one study, delayed union was more common in the cohort with more than three years of BT (67%) than in the group with less than three years of BT (26%). Surgical fixation was associated with improved outcomes compared with non-operative management. BT has been described to be associated with multiple adverse outcomes related to atypical fractures. Current evidence recommends operative management for this patient group. Further investigation is required to evaluate the exact effects of BT on lower limb fractures, in particular typical femoral fractures.

  5. A Polynomial Estimate of Railway Line Delay

    DEFF Research Database (Denmark)

    Cerreto, Fabrizio; Harrod, Steven; Nielsen, Otto Anker

    2017-01-01

    Railway service may be measured by the aggregate delay over a time horizon or due to an event. Timetables for railway service may dampen aggregate delay by addition of additional process time, either supplement time or buffer time. The evaluation of these variables has previously been performed...... by numerical analysis with simulation. This paper proposes an analytical estimate of aggregate delay with a polynomial form. The function returns the aggregate delay of a railway line resulting from an initial, primary, delay. Analysis of the function demonstrates that there should be a balance between the two...

  6. Delay Variation Model with Two Service Queues

    Directory of Open Access Journals (Sweden)

    Filip Rezac

    2010-01-01

    Full Text Available Delay in VoIP technology is very unpleasant issue and therefore a voice packets prioritization must be ensured. To maintain the high call quality a maximum information delivery time from the sender to the recipient is set to 150 ms. This paper focuses on the design of a mathematical model of end-to-end delay of a VoIP connection, in particular on a delay variation. It describes all partial delay components and mechanisms, their generation, facilities and mathematical formulations. A new approach to the delay variation model is presented and its validation has been done by experimention.

  7. Fuzzy delay model based fault simulator for crosstalk delay fault test ...

    Indian Academy of Sciences (India)

    In this paper, a fuzzy delay model based crosstalk delay fault simulator is proposed. As design trends move towards nanometer technologies, more number of new parameters affects the delay of the component. Fuzzy delay models are ideal for modelling the uncertainty found in the design and manufacturing steps.

  8. Precise delay measurement through combinatorial logic

    Science.gov (United States)

    Burke, Gary R. (Inventor); Chen, Yuan (Inventor); Sheldon, Douglas J. (Inventor)

    2010-01-01

    A high resolution circuit and method for facilitating precise measurement of on-chip delays for FPGAs for reliability studies. The circuit embeds a pulse generator on an FPGA chip having one or more groups of LUTS (the "LUT delay chain"), also on-chip. The circuit also embeds a pulse width measurement circuit on-chip, and measures the duration of the generated pulse through the delay chain. The pulse width of the output pulse represents the delay through the delay chain without any I/O delay. The pulse width measurement circuit uses an additional asynchronous clock autonomous from the main clock and the FPGA propagation delay can be displayed on a hex display continuously for testing purposes.

  9. Reasons for diagnostic delay in gynecological malignancies

    DEFF Research Database (Denmark)

    Vandborg, Mai Partridge; Christensen, René dePont Christensen; Kragstrup, Jakob

    2011-01-01

    (≤ or > 60 years), performance of gynecological examination by the GP and notification of cancer suspicion on first referral from GP’s on the diagnostic delay (short delay ≤90 days and long delay >90 days). Results Across cancer type a median total delay of 101 days was observed. The 10% of women......Aim The primary aim of this study was to identify and describe different delay types in women with gynecologic cancer, and to analyze the relationship between diagnostic delay and a number of characteristics for patients, cancers and the health care system. Setting A cohort study of women newly......) and The Danish Gynecological Cancer Database (DGCD). 161 women were included; ovarian cancer: 63, endometrial cancer: 50, cervical cancer: 34 and vulvar cancer: 14. Outcome measures were different delay types counted in days and the influence of four clinical important variables: Presence of alarm symptoms, age...

  10. Temperature Dependent Wire Delay Estimation in Floorplanning

    DEFF Research Database (Denmark)

    Winther, Andreas Thor; Liu, Wei; Nannarelli, Alberto

    2011-01-01

    Due to large variations in temperature in VLSI circuits and the linear relationship between metal resistance and temperature, the delay through wires of the same length can be different. Traditional thermal aware floorplanning algorithms use wirelength to estimate delay and routability. In this w......Due to large variations in temperature in VLSI circuits and the linear relationship between metal resistance and temperature, the delay through wires of the same length can be different. Traditional thermal aware floorplanning algorithms use wirelength to estimate delay and routability....... In this work, we show that using wirelength as the evaluation metric does not always produce a floorplan with the shortest delay. We propose a temperature dependent wire delay estimation method for thermal aware floorplanning algorithms, which takes into account the thermal effect on wire delay. The experiment...

  11. Elite athletes and pubertal delay.

    Science.gov (United States)

    Kapczuk, Karina

    2017-10-01

    Intensive physical training and participation in competitive sports during childhood and early adolescence may affect athletes' pubertal development. On the other hand, pubertal timing, early or late, may impact on an athlete selection for a particular sport. Genetic predisposition, training load, nutritional status and psychological stress determine athletes' pubertal timing. Athletes that practice esthetic sports, especially gymnasts, are predisposed to a delay in pubertal development. The growing evidence indicates that energy deficiency, not a systemic training per se, plays a crucial role in the pathogenesis of functional hypothalamic hypogonadism in female athletes. Metabolic and psychologic stress activate hypothalamic-pituitary-adrenal axis and suppress hypothalamic-pituitary-ovarian axis. Female athletes who do not begin secondary sexual development by the age of 14 or menstruation by the age of 16 warrant a comprehensive evaluation and a targeted treatment. Somatic growth and sexual maturation of elite female athletes are largely sport-specific since each sport favors a particular somatotype and requires a specific training. Chronic negative energy balance resulting from a systemic physical training and inadequate energy intake may delay pubertal development in elite athletes. Youth athletes, especially those engaged in competitive sports that emphasize prepubertal or lean appearance, are at risk of developing relative energy deficiency in sport associated with disordered eating or eating disorders. Management strategies should address the complex conditions underlying functional hypothalamic hypogonadism.

  12. Delayed recombination and cosmic parameters

    International Nuclear Information System (INIS)

    Galli, Silvia; Melchiorri, Alessandro; Bean, Rachel; Silk, Joseph

    2008-01-01

    Current cosmological constraints from cosmic microwave background anisotropies are typically derived assuming a standard recombination scheme, however additional resonance and ionizing radiation sources can delay recombination, altering the cosmic ionization history and the cosmological inferences drawn from the cosmic microwave background data. We show that for recent observations of the cosmic microwave background anisotropy, from the Wilkinson microwave anisotropy probe satellite mission (WMAP) 5-year survey and from the arcminute cosmology bolometer array receiver experiment, additional resonance radiation is nearly degenerate with variations in the spectral index, n s , and has a marked effect on uncertainties in constraints on the Hubble constant, age of the universe, curvature and the upper bound on the neutrino mass. When a modified recombination scheme is considered, the redshift of recombination is constrained to z * =1078±11, with uncertainties in the measurement weaker by 1 order of magnitude than those obtained under the assumption of standard recombination while constraints on the shift parameter are shifted by 1σ to R=1.734±0.028. From the WMAP5 data we obtain the following constraints on the resonance and ionization sources parameters: ε α i <0.058 at 95% c.l.. Although delayed recombination limits the precision of parameter estimation from the WMAP satellite, we demonstrate that this should not be the case for future, smaller angular scales measurements, such as those by the Planck satellite mission.

  13. Asymptotic Delay Analysis for Cross-Layer Delay-Based Routing in Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Philippe Jacquet

    2007-01-01

    Full Text Available This paper addresses the problem of the evaluation of the delay distribution via analytical means in IEEE 802.11 wireless ad hoc networks. We show that the asymptotic delay distribution can be expressed as a power law. Based on the latter result, we present a cross-layer delay estimation protocol and we derive new delay-distribution-based routing algorithms, which are well adapted to the QoS requirements of real-time multimedia applications. In fact, multimedia services are not sensitive to average delays, but rather to the asymptotic delay distributions. Indeed, video streaming applications drop frames when they are received beyond a delay threshold, determined by the buffer size. Although delay-distribution-based routing is an NP-hard problem, we show that it can be solved in polynomial time when the delay threshold is large, because of the asymptotic power law distribution of the link delays.

  14. Bleeding and infection with external ventricular drainage: a systematic review in comparison with adjudicated adverse events in the ongoing Clot Lysis Evaluating Accelerated Resolution of Intraventricular Hemorrhage Phase III (CLEAR-III IHV) trial.

    Science.gov (United States)

    Dey, Mahua; Stadnik, Agnieszka; Riad, Fady; Zhang, Lingjiao; McBee, Nichol; Kase, Carlos; Carhuapoma, J Ricardo; Ram, Malathi; Lane, Karen; Ostapkovich, Noeleen; Aldrich, Francois; Aldrich, Charlene; Jallo, Jack; Butcher, Ken; Snider, Ryan; Hanley, Daniel; Ziai, Wendy; Awad, Issam A

    2015-03-01

    Retrospective series report varied rates of bleeding and infection with external ventricular drainage (EVD). There have been no prospective studies of these risks with systematic surveillance, threshold definitions, or independent adjudication. To analyze the rate of complications in the ongoing Clot Lysis: Evaluating Accelerated Resolution of Intraventricular Hemorrhage Phase III (CLEAR III) trial, providing a comparison with a systematic review of complications of EVD in the literature. Patients were prospectively enrolled in the CLEAR III trial after placement of an EVD for obstructive intraventricular hemorrhage and randomized to receive recombinant tissue-type plasminogen activator or placebo. We counted any detected new hemorrhage (catheter tract hemorrhage or any other distant hemorrhage) on computed tomography scan within 30 days from the randomization. Meta-analysis of published series of EVD placement was compiled with STATA software. Growing or unstable hemorrhage was reported as a cause of exclusion from the trial in 74 of 5707 cases (1.3%) screened for CLEAR III. The first 250 patients enrolled have completed adjudication of adverse events. Forty-two subjects (16.8%) experienced ≥1 new bleeds or expansions, and 6 of 250 subjects (2.4%) suffered symptomatic hemorrhages. Eleven cases (4.4%) had culture-proven bacterial meningitis or ventriculitis. Risks of bleeding and infection in the ongoing CLEAR III trial are comparable to those previously reported in EVD case series. In the present study, rates of new bleeds and bacterial meningitis/ventriculitis are very low despite multiple daily injections, blood in the ventricles, the use of thrombolysis in half the cases, and generalization to >60 trial sites.

  15. Nerve conduction velocity

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003927.htm Nerve conduction velocity To use the sharing features on this page, please enable JavaScript. Nerve conduction velocity (NCV) is a test to see ...

  16. Conducting Polymeric Materials

    DEFF Research Database (Denmark)

    Hvilsted, Søren

    2016-01-01

    The overall objective of this collection is to provide the most recent developments within the various areas of conducting polymeric materials. The conductivity of polymeric materials is caused by electrically charged particles, ions, protons and electrons. Materials in which electrons...

  17. Ranking of delay factors in construction projects after Egyptian revolution

    Directory of Open Access Journals (Sweden)

    Remon Fayek Aziz

    2013-09-01

    Full Text Available Time is one of the major considerations throughout project management life cycle and can be regarded as one of the most important parameters of a project and the driving force of project success. Time delay is a very frequent phenomenon and is almost associated with nearly all constructing projects. However, little effort has been made to curtail the phenomenon, this research work attempts to identify, investigate, and rank factors perceived to affect delays in the Egyptian construction projects with respect to their relative importance so as to proffer possible ways of coping with this phenomenon. To achieve this objective, researcher invited practitioners and experts, comprising a statistically representative sample to participate in a structured questionnaire survey. Brain storming was taken into consideration, through which a number of delay factors were identified in construction projects. Totally, ninety-nine (99 factors were short-listed to be made part of the questionnaire survey and were identified and categorized into nine (9 major categories. The survey was conducted with experts and representatives from private, public, and local general construction firms. The data were analyzed using Relative Importance Index (RII, ranking and simple percentages. Ranking of factors and categories was demonstrated according to their importance level on delay, especially after 25/1/2011 (Egyptian revolution. According to the case study results, the most contributing factors and categories (those need attention to delays were discussed, and some recommendations were made in order to minimize and control delays in construction projects. Also, this paper can serve as a guide for all construction parties with effective management in construction projects to achieve a competitive level of quality and a time effective project.

  18. Ignition Delay of Combustible Materials in Normoxic Equivalent Environments

    Science.gov (United States)

    McAllister, Sara; Fernandez-Pello, Carlos; Ruff, Gary; Urban, David

    2009-01-01

    Material flammability is an important factor in determining the pressure and composition (fraction of oxygen and nitrogen) of the atmosphere in the habitable volume of exploration vehicles and habitats. The method chosen in this work to quantify the flammability of a material is by its ease of ignition. The ignition delay time was defined as the time it takes a combustible material to ignite after it has been exposed to an external heat flux. Previous work in the Forced Ignition and Spread Test (FIST) apparatus has shown that the ignition delay in the currently proposed space exploration atmosphere (approximately 58.6 kPa and32% oxygen concentration) is reduced by 27% compared to the standard atmosphere used in the Space Shuttle and Space Station. In order to determine whether there is a safer environment in terms of material flammability, a series of piloted ignition delay tests using polymethylmethacrylate (PMMA) was conducted in the FIST apparatus to extend the work over a range of possible exploration atmospheres. The exploration atmospheres considered were the normoxic equivalents, i.e. reduced pressure conditions with a constant partial pressure of oxygen. The ignition delay time was seen to decrease as the pressure was reduced along the normoxic curve. The minimum ignition delay observed in the normoxic equivalent environments was nearly 30% lower than in standard atmospheric conditions. The ignition delay in the proposed exploration atmosphere is only slightly larger than this minimum. Interms of material flammability, normoxic environments with a higher pressure relative to the proposed pressure would be desired.

  19. Electrically conductive composite material

    Science.gov (United States)

    Clough, Roger L.; Sylwester, Alan P.

    1989-01-01

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistant pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like.

  20. Effect of delay in hospital presentation on clinical and imaging findings in acute pulmonary thromboembolism.

    Science.gov (United States)

    Jenab, Yaser; Alemzadeh-Ansari, Mohammad Javad; Fehri, Seyedeh Arezoo; Ghaffari-Marandi, Neda; Jalali, Arash

    2014-04-01

    There is limited information on the extent and clinical importance of the delay in hospital presentation of acute pulmonary thromboembolism (PTE). The aim of this study was to investigate the delay in hospital presentation of PTE and its association with clinical and imaging findings in PTE. This prospective study was conducted on patients admitted to our hospital with a diagnosis of acute PTE between September 2007 and September 2011. Relationships between delay in hospital presentation and clinical findings, risk factors, imaging findings, and in-hospital mortality were analyzed. Of the 195 patients enrolled, 84 (43.1%) patients presented 3 days after the onset of symptoms. Patients with chest pain, history of immobility for more than 3 days, recent surgery, and estrogen use had significantly less delayed presentation. Right ventricular dysfunction was significantly more frequent in patients with delayed presentation (odds ratio [OR] = 2.38; 95% confidence interval [CI] 1.27-4.44; p = 0.006); however, no relationship was found between delay in presentation and pulmonary computed tomographic angiography or color Doppler sonography findings. Patients with delayed presentation were at higher risk of in-hospital mortality (OR = 4.32; 95% CI 1.12-16.49; p = 0.021). Our study showed that a significant portion of patients with acute PTE had delayed presentation. Also, patients with delayed presentation had worse echocardiographic findings and higher in-hospital mortality. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Dynamics of Nonlinear Time-Delay Systems

    CERN Document Server

    Lakshmanan, Muthusamy

    2010-01-01

    Synchronization of chaotic systems, a patently nonlinear phenomenon, has emerged as a highly active interdisciplinary research topic at the interface of physics, biology, applied mathematics and engineering sciences. In this connection, time-delay systems described by delay differential equations have developed as particularly suitable tools for modeling specific dynamical systems. Indeed, time-delay is ubiquitous in many physical systems, for example due to finite switching speeds of amplifiers in electronic circuits, finite lengths of vehicles in traffic flows, finite signal propagation times in biological networks and circuits, and quite generally whenever memory effects are relevant. This monograph presents the basics of chaotic time-delay systems and their synchronization with an emphasis on the effects of time-delay feedback which give rise to new collective dynamics. Special attention is devoted to scalar chaotic/hyperchaotic time-delay systems, and some higher order models, occurring in different bran...

  2. Group Delay of High Q Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2013-01-01

    Group Delay variations versus frequency is an essential factor which can cause distortion and degradation in the signals. Usually this is an issue in wideband communication systems, such as satellite communication systems, which are used for transmitting wideband data. However, group delay can also...... become an issue, when working with high Q antennas, because of the steep phase shift over the frequency. In this paper, it is measured how large group delay variations can become, when going from a low Q antenna to a high Q antenna. The group delay of a low Q antenna is shown to be around 1.3 ns, whereas...... a high Q antenna has group delay of around 22 ns. It is due to this huge group delay variation characteristics of high Q antennas, that signal distortion might occur in the radio system with high Q antennas....

  3. Permutation entropy with vector embedding delays

    Science.gov (United States)

    Little, Douglas J.; Kane, Deb M.

    2017-12-01

    Permutation entropy (PE) is a statistic used widely for the detection of structure within a time series. Embedding delay times at which the PE is reduced are characteristic timescales for which such structure exists. Here, a generalized scheme is investigated where embedding delays are represented by vectors rather than scalars, permitting PE to be calculated over a (D -1 ) -dimensional space, where D is the embedding dimension. This scheme is applied to numerically generated noise, sine wave and logistic map series, and experimental data sets taken from a vertical-cavity surface emitting laser exhibiting temporally localized pulse structures within the round-trip time of the laser cavity. Results are visualized as PE maps as a function of embedding delay, with low PE values indicating combinations of embedding delays where correlation structure is present. It is demonstrated that vector embedding delays enable identification of structure that is ambiguous or masked, when the embedding delay is constrained to scalar form.

  4. Delays in the management of retroperitoneal sarcomas

    DEFF Research Database (Denmark)

    Seinen, Jojanneke; Almquist, Martin; Styring, Emelie

    2010-01-01

    Retroperitoneal sarcomas are rare and treatment should optimally be centralized. Despite successful centralization with 90% of the patients referred prior to surgery, delays occur, which led us to assess lead times in a population-based series. Method. Patients diagnosed with retroperitoneal...... sarcoma in the southern Sweden health care region 2003-2009 were eligible for the study. Data on referrals and diagnostic investigations were collected from clinical files from primary health care, local hospitals, and from the sarcoma centre. Lead times were divided into patient delays and health care...... delays caused by primary health care, local hospitals, or procedures at the sarcoma centre. Results. Complete data were available from 33 patients and demonstrated a median patient delay of 23¿days (0-17¿months) and median health care delay of 94¿days (1-40¿months) with delays of median 15¿days...

  5. Time Delay Estimation Algoritms for Echo Cancellation

    Directory of Open Access Journals (Sweden)

    Kirill Sakhnov

    2011-01-01

    Full Text Available The following case study describes how to eliminate echo in a VoIP network using delay estimation algorithms. It is known that echo with long transmission delays becomes more noticeable to users. Thus, time delay estimation, as a part of echo cancellation, is an important topic during transmission of voice signals over packetswitching telecommunication systems. An echo delay problem associated with IP-based transport networks is discussed in the following text. The paper introduces the comparative study of time delay estimation algorithm, used for estimation of the true time delay between two speech signals. Experimental results of MATLab simulations that describe the performance of several methods based on cross-correlation, normalized crosscorrelation and generalized cross-correlation are also presented in the paper.

  6. CGI delay compensation. [Computer Generated Image

    Science.gov (United States)

    Mcfarland, R. E.

    1986-01-01

    Computer-generated graphics in real-time helicopter simulation produces objectionable scene-presentation time delays. In the flight simulation laboratory at Ames Research Center, it has been determined that these delays have an adverse influence on pilot performance during agressive tasks such as nap of the earth (NOE) maneuvers. Using contemporary equipment, computer generated image (CGI) time delays are an unavoidable consequence of the operations required for scene generation. However, providing that magnitude distortions at higher frequencies are tolerable, delay compensation is possible over a restricted frequency range. This range, assumed to have an upper limit of perhaps 10 or 15 rad/sec, conforms approximately to the bandwidth associated with helicopter handling qualities research. A compensation algorithm is introduced here and evaluated in terms of tradeoffs in frequency responses. The algorithm has a discrete basis and accommodates both a large, constant transport delay interval and a periodic delay interval, as associated with asynchronous operations.

  7. Memorized discrete systems and time-delay

    CERN Document Server

    Luo, Albert C J

    2017-01-01

    This book examines discrete dynamical systems with memory—nonlinear systems that exist extensively in biological organisms and financial and economic organizations, and time-delay systems that can be discretized into the memorized, discrete dynamical systems. It book further discusses stability and bifurcations of time-delay dynamical systems that can be investigated through memorized dynamical systems as well as bifurcations of memorized nonlinear dynamical systems, discretization methods of time-delay systems, and periodic motions to chaos in nonlinear time-delay systems. The book helps readers find analytical solutions of MDS, change traditional perturbation analysis in time-delay systems, detect motion complexity and singularity in MDS; and determine stability, bifurcation, and chaos in any time-delay system.

  8. CAN LARGE TIME DELAYS OBSERVED IN LIGHT CURVES OF CORONAL LOOPS BE EXPLAINED IN IMPULSIVE HEATING?

    International Nuclear Information System (INIS)

    Lionello, Roberto; Linker, Jon A.; Mikić, Zoran; Alexander, Caroline E.; Winebarger, Amy R.

    2016-01-01

    The light curves of solar coronal loops often peak first in channels associated with higher temperatures and then in those associated with lower temperatures. The delay times between the different narrowband EUV channels have been measured for many individual loops and recently for every pixel of an active region observation. The time delays between channels for an active region exhibit a wide range of values. The maximum time delay in each channel pair can be quite large, i.e., >5000 s. These large time delays make-up 3%–26% (depending on the channel pair) of the pixels where a trustworthy, positive time delay is measured. It has been suggested that these time delays can be explained by simple impulsive heating, i.e., a short burst of energy that heats the plasma to a high temperature, after which the plasma is allowed to cool through radiation and conduction back to its original state. In this paper, we investigate whether the largest observed time delays can be explained by this hypothesis by simulating a series of coronal loops with different heating rates, loop lengths, abundances, and geometries to determine the range of expected time delays between a set of four EUV channels. We find that impulsive heating cannot address the largest time delays observed in two of the channel pairs and that the majority of the large time delays can only be explained by long, expanding loops with photospheric abundances. Additional observations may rule out these simulations as an explanation for the long time delays. We suggest that either the time delays found in this manner may not be representative of real loop evolution, or that the impulsive heating and cooling scenario may be too simple to explain the observations, and other potential heating scenarios must be explored

  9. Magnetic pulse sharpener and delay-line

    International Nuclear Information System (INIS)

    Li Jin; Dai Guangsen; Xia Liansheng

    2002-01-01

    This paper describes a method to achieve short rise time pulse which has been delayed with a delay-line and magnetic pulse sharpener. A delay-line and two shock-lines are designed to carry pulsed signal with a maximum voltage magnitude up to 80 kV. A pulse of High voltage with arise time of 48 ns at a level of 0.1%-0.9% were achieved, and the attenuation in the line is very small

  10. Does Bilingualism Delay the Development of Dementia?

    OpenAIRE

    Amy L Atkinson

    2016-01-01

    It has been suggested that bilingualism (where individuals speak two languages) may delay the development of dementia. However, much of the research is inconclusive. Some researchers have reported that bilingualism delays the onset and diagnosis of dementia, whilst other studies have found weak or even detrimental effects. This paper reviews a series of nine empirical studies, published up until March 2016, which investigated whether bilingualism significantly delays the onset of dementia. Th...

  11. Delayed enhanced MRI in intraparenchymal tumors

    International Nuclear Information System (INIS)

    Eguchi, Takahiko; Morimoto, Tetsuya; Takeshima, Toshikazu

    1991-01-01

    Delayed enhanced MRI was performed on 20 intraparenchymal tumors, and these findings were compared with those of early enhanced MRI. Using the spin-echo technique (SE: 400-500/20 msec), early scans were obtained 5 minutes, and delayed scans were obtained 60 minutes, after the intravenous injection of 0.1 nmol of gadolinium-DTPA/Kg. We discussed the changes in the delayed scan with regard to the change in the pattern of enhancement and the boundary of enhancement. In these twenty intraparenchymal tumors, there were three low-grade astrocytomas, two anaplastic astrocytomas, seven glioblastomas, and eight metastatic tumors. The changes in the enhanced pattern showed three types as follows: Type I: heterogeneous enhancement in both early and delayed scans; Type II: heterogeneous enhancement in early scan and homogeneous enhancement in delayed scan; Type III: homogeneous enhancement in both early and delayed scans. Most malignant tumors, such as glioblastomas (6/8), anaplastic astrocytomas (2/2), and metastatic tumors (7/8), revealed Type I, although low-grade astrocytomas showed Type II (3/2) and Type III (1/3). The heterogeneous enhancement in delayed scan was found in malignant tumors and in low-grade astrocytoma; even if the early scan revealed heterogeneous enhancement, the delayed scan showed homogeneous enhancement. In the delayed scan, most enhanced boundaries spread out of the boundaries in the early scan. Glioblastomas spread markedly in the delayed scan, although none of the low-grade astrocytomas, anaplastic astrocytomas, or metastases revealed marked spreading. We called these marked increases in the delayed scan a 'spreading sign' and thought that this sign was specific to glioblastomas. Recently some authors have emphasized the usefulness of serial scans. Delayed enhanced MRI 60 minutes after the administration of a contrast medium was here found also to be useful for the accurate diagnosis for brain tumors. (author)

  12. Graphene Conductance Uniformity Mapping

    DEFF Research Database (Denmark)

    Buron, Jonas Christian Due; Petersen, Dirch Hjorth; Bøggild, Peter

    2012-01-01

    We demonstrate a combination of micro four-point probe (M4PP) and non-contact terahertz time-domain spectroscopy (THz-TDS) measurements for centimeter scale quantitative mapping of the sheet conductance of large area chemical vapor deposited graphene films. Dual configuration M4PP measurements......, demonstrated on graphene for the first time, provide valuable statistical insight into the influence of microscale defects on the conductance, while THz-TDS has potential as a fast, non-contact metrology method for mapping of the spatially averaged nanoscopic conductance on wafer-scale graphene with scan times......, dominating the microscale conductance of the investigated graphene film....

  13. Electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  14. Neutron stochastic transport theory with delayed neutrons

    International Nuclear Information System (INIS)

    Munoz-Cobo, J.L.; Verdu, G.

    1987-01-01

    From the stochastic transport theory with delayed neutrons, the Boltzmann transport equation with delayed neutrons for the average flux emerges in a natural way without recourse to any approximation. From this theory a general expression is obtained for the Feynman Y-function when delayed neutrons are included. The single mode approximation for the particular case of a subcritical assembly is developed, and it is shown that Y-function reduces to the familiar expression quoted in many books, when delayed neutrons are not considered, and spatial and source effects are not included. (author)

  15. Complex conductivity of soils

    NARCIS (Netherlands)

    Revil, A.; Coperey, A.; Shao, Z.; Florsch, N.; Fabricus, I.L.; Deng, Y.; Delsman, J.R.; Pauw, P.S.; Karaoulis, M.; Louw, P.G.B. de; Baaren, E.S. van; Dabekaussen, W.; Menkovic, A.; Gunnink, J.L.

    2017-01-01

    The complex conductivity of soils remains poorly known despite the growing importance of this method in hydrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including four peat samples) and one clean sand in the frequency range 0.1 Hz

  16. Conducting polymer hydrogels

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav

    2017-01-01

    Roč. 71, č. 2 (2017), s. 269-291 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 Keywords : aerogel * conducting polymers * conductivity Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.258, year: 2016

  17. Controllability and stability of primary frequency control from thermostatic loads with delays

    DEFF Research Database (Denmark)

    Ziras, Charalampos; Vrettos, Evangelos; You, Shi

    2017-01-01

    There is an increasing interest in exploiting the flexibility of loads to provide ancillary services to the grid. In this paper we study how response delays and lockout constraints affect the controllability of an aggregation of refrigerators offering primary frequency control (PFC). First we...... examine the effect of delays in PFC provision from an aggregation of refrigerators, using a two-area power system. We propose a framework to systematically address frequency measurement and response delays and we determine safe values for the total delays via simulations. We introduce a controllability...... index to evaluate PFC provision under lockout constraints of refrigerators compressors. We conduct extensive simulations to study the effects of measurement delay, ramping times, lockout durations and rotational inertia on the controllability of the aggregation and system stability. Finally, we discuss...

  18. Conductivities from attractors

    Energy Technology Data Exchange (ETDEWEB)

    Erdmenger, Johanna [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 Munich (Germany); Institut für Theoretische Physik und Astrophysik, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg (Germany); Fernández, Daniel [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 Munich (Germany); Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavík (Iceland); Goulart, Prieslei [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 Munich (Germany); Instituto de Física Teórica, UNESP-Universidade Estadual Paulista,R. Dr. Bento T. Ferraz 271, Bl. II, São Paulo 01140-070, SP (Brazil); Witkowski, Piotr [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 Munich (Germany)

    2017-03-28

    In the context of applications of the AdS/CFT correspondence to condensed matter physics, we compute conductivities for field theory duals of dyonic planar black holes in 3+1-dimensional Einstein-Maxwell-dilaton theories at zero temperature. We combine the near-horizon data obtained via Sen’s entropy function formalism with known expressions for conductivities. In this way we express the conductivities in terms of the extremal black hole charges. We apply our approach to three different examples for dilaton theories for which the background geometry is not known explicitly. For a constant scalar potential, the thermoelectric conductivity explicitly scales as α{sub xy}∼N{sup 3/2}, as expected. For the same model, our approach yields a finite result for the heat conductivity κ/T∝N{sup 3/2} even for T→0.

  19. Thermal conductivity of technetium

    International Nuclear Information System (INIS)

    Minato, K.; Serizawa, H.; Fukuda, K.

    1998-01-01

    The thermal diffusivity of technetium was measured on a disk sample of 5 mm in diameter and 1 mm in thickness by the laser flash method from room temperature to 1173 K, and the thermal conductivity was determined by the measured thermal diffusivity and density, and the reported specific heat capacity. The thermal diffusivity of technetium decreases with increasing temperature though it is almost constant above 600 K. The thermal conductivity of technetium shows a minimum around 400 K, above which the thermal conductivity increases with temperature. The electronic and phonon components of the thermal conductivity were evaluated approximately. The increase in the thermal conductivity of technetium with temperature is due to the increase in the electronic component. (orig.)

  20. Delayed habituation in Behcet's disease.

    Science.gov (United States)

    Gulturk, Sefa; Akyol, Melih; Kececi, Hulusi; Ozcelik, Sedat; Cinar, Ziynet; Demirkazik, Ayse

    2008-01-01

    The autonomic nervous system in Behcet's patients may be affected due to various reasons. This entity may be detected with the measurement of the electrodermal activities, heart rate variability and pupillometric methods. Habituation is one of the implicit forms of learning and memory and the loss of habituation can reveal pathological changes in the synaptic regions. To determine whether there is a functional decrease in the synaptic effectiveness (habituation) of the pathways to sympathetic neurons that had been repeatedly activated in Behcet's. Twelve patients with Behcet's disease and 12 healthy controls were included in the study. Sympathetic skin potential (SSP) records were taken at normal room temperature in a quiet place within a Faraday cage. Sixteen square wave single shock impulses (duration: 1200 ms, strength: 5 mA) were applied on each case. After the 1st stimulus, the SSP amplitudes were lower in the patients compared to the controls (P0.05). Whereas there was no significant differences among the SSP amplitudes after the 9th impulse in the controls (P>0.05). The habituation rate of the SSP after consecutive impulses was slowest in the patients compared to controls (P<0.001, t value=12.39). There is a delayed habituation in Behcet's disease and that may due to pathologic changes with vasculitis through their peripheral nerves.

  1. Diagnostic and treatment delay among pulmonary tuberculosis patients in Ethiopia: a cross sectional study

    Directory of Open Access Journals (Sweden)

    Yimer Solomon

    2005-12-01

    Full Text Available Abstract Background Delayed diagnosis and treatment of tuberculosis (TB results in severe disease and a higher mortality. It also leads to an increased period of infectivity in the community. The objective of this study was to determine the length of delays, and analyze the factors affecting the delay from onset of symptoms of pulmonary tuberculosis (PTB until the commencement of treatment. Methods In randomly selected TB management units (TBMUs, i.e. government health institutions which have diagnosing and treatment facilities for TB in Amhara Region, we conducted a cross sectional study from September 1-December 31/2003. Delay was analyzed from two perspectives, 1. Period between onset of TB symptoms to first visit to any health provider (health seeking period, and from the first health provider visit to initiation of treatment (health providers' delay, and 2. Period between onset of TB symptoms to first visit to a medical provider (patients' delay, and from this visit to commencement of anti-TB treatment (health systems' delay. Patients were interviewed on the same date of diagnosis using a semi-structured questionnaire. Logistics regression analysis was applied to analyze the risk factors of delays. Results A total of 384 new smear positive PTB patients participated in the study. The median total delay was 80 days. The median health-seeking period and health providers' delays were 15 and 61 days, respectively. Conversely, the median patients' and health systems' delays were 30 and 21 days, respectively. Taking medical providers as a reference point, we found that forty eight percent of the subjects delayed for more than one month. Patients' delays were strongly associated with first visit to non-formal health providers and self treatment (P Conclusion Delay in the diagnosis and treatment of PTB is unacceptably high in Amhara region. Health providers' and health systems' delays represent the major portion of the total delay. Accessing a

  2. Feedback and feedforward adaptation to visuomotor delay during reaching and slicing movements.

    Science.gov (United States)

    Botzer, Lior; Karniel, Amir

    2013-07-01

    It has been suggested that the brain and in particular the cerebellum and motor cortex adapt to represent the environment during reaching movements under various visuomotor perturbations. It is well known that significant delay is present in neural conductance and processing; however, the possible representation of delay and adaptation to delayed visual feedback has been largely overlooked. Here we investigated the control of reaching movements in human subjects during an imposed visuomotor delay in a virtual reality environment. In the first experiment, when visual feedback was unexpectedly delayed, the hand movement overshot the end-point target, indicating a vision-based feedback control. Over the ensuing trials, movements gradually adapted and became accurate. When the delay was removed unexpectedly, movements systematically undershot the target, demonstrating that adaptation occurred within the vision-based feedback control mechanism. In a second experiment designed to broaden our understanding of the underlying mechanisms, we revealed similar after-effects for rhythmic reversal (out-and-back) movements. We present a computational model accounting for these results based on two adapted forward models, each tuned for a specific modality delay (proprioception or vision), and a third feedforward controller. The computational model, along with the experimental results, refutes delay representation in a pure forward vision-based predictor and suggests that adaptation occurred in the forward vision-based predictor, and concurrently in the state-based feedforward controller. Understanding how the brain compensates for conductance and processing delays is essential for understanding certain impairments concerning these neural delays as well as for the development of brain-machine interfaces. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  3. Radiation-induced conductivity of polynaphthoyl benzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Tiutnev, A P; Berlin, A M; Saenko, V S; Rusanov, A L; Korshak, V V

    1985-01-01

    The nonstationary radiation-induced conductivity of polynaphthoyl benzimidazole, synthesized by single-stage high-temperature catalytic polycondensation, is investigated experimentally. It is shown that the radiation-induced conductivity of this material is characterized by an anomalous (non-Gaussian) transfer of excess charge carriers. The activation energy of the delayed component (0.1 ms after pulse termination) is determined to be 0.12 eV; the volt-ampere characteristic of this component is nonlinear, with the coefficient of nonlinearity increasing with the intensity of the external electric field. Experimental results are interpreted on the basis of the phenomenological theory of jump conductivity proposed by Zviagin. 15 references.

  4. Measurement of thermal conductance

    International Nuclear Information System (INIS)

    Kuchnir, M.

    1977-01-01

    The 6-m long, 45-kG, warm-iron superconducting magnets envisioned for the Energy Doubler stage of the Fermilab accelerator require stiff supports with minimized thermal conductances in order to keep the refrigeration power reasonable. The large number of supports involved in the system required a careful study of their heat conduction from the room temperature wall to the intercepting refrigeration at 20 0 K and to the liquid helium. For this purpose the thermal conductance of this support was measured by comparing it with the thermal conductance of a copper strap of known geometry. An association of steady-state thermal analysis and experimental thermal conductivity techniques forms the basis of this method. An important advantage is the automatic simulation of the 20 0 K refrigeration intercept by the copper strap, which simplifies the apparatus considerably. This relative resistance technique, which uses electrical analogy as a guideline, is applicable with no restrictions for materials with temperature-independent thermal conductivity. For other materials the results obtained are functions of the specific temperature interval involved in the measurements. A comprehensive review of the literature on thermal conductivity indicates that this approach has not been used before. A demonstration of its self-consistency is stressed here rather than results obtained for different supports

  5. Time delays, population, and economic development

    Science.gov (United States)

    Gori, Luca; Guerrini, Luca; Sodini, Mauro

    2018-05-01

    This research develops an augmented Solow model with population dynamics and time delays. The model produces either a single stationary state or multiple stationary states (able to characterise different development regimes). The existence of time delays may cause persistent fluctuations in both economic and demographic variables. In addition, the work identifies in a simple way the reasons why economics affects demographics and vice versa.

  6. On Delay and Security in Network Coding

    Science.gov (United States)

    Dikaliotis, Theodoros K.

    2013-01-01

    In this thesis, delay and security issues in network coding are considered. First, we study the delay incurred in the transmission of a fixed number of packets through acyclic networks comprised of erasure links. The two transmission schemes studied are routing with hop-by-hop retransmissions, where every node in the network simply stores and…

  7. Delaying Developmental Mathematics: The Characteristics and Costs

    Science.gov (United States)

    Johnson, Marianne; Kuennen, Eric

    2004-01-01

    This paper investigates which students delay taking a required developmental mathematics course and the impact of delay on student performance in introductory microeconomics. Analysis of a sample of 1462 students at a large Midwestern university revealed that, although developmental-level mathematics students did not reach the same level of…

  8. ANALYSING SURFACE MOVEMENT DELAYS IN AN AIRPORT

    Directory of Open Access Journals (Sweden)

    Volodymyr Kharchenko

    2014-07-01

    Full Text Available Queuing effect can be in the different components of ground operations. Causes of surface – movement delays are long taxi – in and taxi – out operations during departure and arrival of aircraft. Surface movement delays in an airport are analyzed

  9. Analyzing delay causes in Egyptian construction projects

    Directory of Open Access Journals (Sweden)

    Mohamed M. Marzouk

    2014-01-01

    Full Text Available Construction delays are common problems in civil engineering projects in Egypt. These problems occur frequently during project life-time leading to disputes and litigation. Therefore, it is essential to study and analyze causes of construction delays. This research presents a list of construction delay causes retrieved from literature. The feedback of construction experts was obtained through interviews. Subsequently, a questionnaire survey was prepared. The questionnaire survey was distributed to thirty-three construction experts who represent owners, consultants, and contractor’s organizations. Frequency Index, Severity Index, and Importance Index are calculated and according to the highest values of them the top ten delay causes of construction projects in Egypt are determined. A case study is analyzed and compared to the most important delay causes in the research. Statistical analysis is carried out using analysis of variance ANOVA method to test delay causes, obtained from the survey. The test results reveal good correlation between groups while there is significant difference between them for some delay causes and finally roadmap for prioritizing delay causes groups is presented.

  10. Algebraic entropy for differential-delay equations

    OpenAIRE

    Viallet, Claude M.

    2014-01-01

    We extend the definition of algebraic entropy to a class of differential-delay equations. The vanishing of the entropy, as a structural property of an equation, signals its integrability. We suggest a simple way to produce differential-delay equations with vanishing entropy from known integrable differential-difference equations.

  11. A Polynomial Estimate of Railway Line Delay

    DEFF Research Database (Denmark)

    Cerreto, Fabrizio; Harrod, Steven; Nielsen, Otto Anker

    2017-01-01

    Railway service may be measured by the aggregate delay over a time horizon or due to an event. Timetables for railway service may dampen aggregate delay by addition of additional process time, either supplement time or buffer time. The evaluation of these variables has previously been performed...

  12. Test Anxiety and Academic Delay of Gratification

    Science.gov (United States)

    Bembenutty, Hefer

    2009-01-01

    The present study examined the relationship between college students' willingness to delay gratification, motivation, self-regulation of learning, and their level of test anxiety (N = 364). Academic delay of gratification refers to students' postponement of immediately available opportunities to satisfy impulses in favor of pursuing academic…

  13. Delaying gratification depends on social trust

    Science.gov (United States)

    Michaelson, Laura; de la Vega, Alejandro; Chatham, Christopher H.; Munakata, Yuko

    2013-01-01

    Delaying gratification is hard, yet predictive of important life outcomes, such as academic achievement and physical health. Prominent theories focus on the role of self-control, hypersensitivity to immediate rewards, and the cost of time spent waiting. However, delaying gratification may also require trust in people delivering future rewards as promised. To test the role of social trust, participants were presented with character vignettes and faces that varied in trustworthiness, and then choose between hypothetical smaller immediate or larger delayed rewards from those characters. Across two experiments, participants were less willing to wait for delayed rewards from less trustworthy characters, and perceived trustworthiness predicted willingness to delay gratification. These findings provide the first demonstration of a causal role for social trust in willingness to delay gratification, independent of other relevant factors, such as self-control or reward history. Thus, delaying gratification requires choosing not only a later reward, but a reward that is potentially less likely to be delivered, when there is doubt about the person promising it. Implications of this work include the need to revise prominent theories of delay of gratification, and new directions for interventions with populations characterized by impulsivity. PMID:23801977

  14. Delaying gratification depends on social trust

    Directory of Open Access Journals (Sweden)

    Laura eMichaelson

    2013-06-01

    Full Text Available Delaying gratification is hard, yet predictive of important life outcomes, such as academic achievement and physical health. Prominent theories focus on the role of self-control, hypersensitivity to immediate rewards, and the cost of time spent waiting. However, delaying gratification may also require trust in people delivering future rewards as promised. To test the role of social trust, participants were presented with character vignettes and faces that varied in trustworthiness, and then chose between hypothetical smaller immediate or larger delayed rewards from those characters. Across two experiments, participants were less willing to wait for delayed rewards from less trustworthy characters, and perceived trustworthiness predicted willingness to delay gratification. These findings provide the first demonstration of a causal role for social trust in willingness to delay gratification, independent of other relevant factors, such as self-control or reward history. Thus, delaying gratification requires choosing not only a later reward, but a reward that is potentially less likely to be delivered, when there is doubt about the person promising it. Implications of this work include the need to revise prominent theories of delay of gratification, and new directions for interventions with populations characterized by impulsivity.

  15. Beta delayed particle emission in light nuclei

    International Nuclear Information System (INIS)

    Riisager, K.; Gabelmann, H.

    1991-01-01

    A short discussion of theoretical treatments of beta delayed particle emission is followed by a presentation of data on the newly found beta delayed deuteron decay of 6 He. This decay cannot be described properly with existing theories. (author) 8 refs.; 3 figs

  16. Allee effects on population dynamics with delay

    International Nuclear Information System (INIS)

    Celik, C.; Merdan, H.; Duman, O.; Akin, O.

    2008-01-01

    In this paper, we study the stability analysis of equilibrium points of population dynamics with delay when the Allee effect occurs at low population density. Mainly, our mathematical results and numerical simulations point to the stabilizing effect of the Allee effects on population dynamics with delay

  17. Nonlinear delay monopoly with bounded rationality

    International Nuclear Information System (INIS)

    Matsumoto, Akio; Szidarovszky, Ferenc

    2012-01-01

    The purpose of this paper is to study the dynamics of a monopolistic firm in a continuous-time framework. The firm is assumed to be boundedly rational and to experience time delays in obtaining and implementing information on output. The dynamic adjustment process is based on the gradient of the expected profit. The paper is divided into three parts: we examine delay effects on dynamics caused by one-time delay and two-time delays in the first two parts. Global dynamics and analytical results on local dynamics are numerically confirmed in the third part. Four main results are demonstrated. First, the stability switch from stability to instability occurs only once in the case of a single delay. Second, the alternation of stability and instability can continue if two time delays are involved. Third, the occurence of Hopf bifurcation is analytically shown if stability is lost. Finally, in a bifurcation process, there are a period-doubling cascade to chaos and a period-halving cascade to the equilibrium point in the case of two time delays if the difference between the two delays is large.

  18. Multivalent ion conducting solids

    Energy Technology Data Exchange (ETDEWEB)

    Imanaka, N. [Osaka Univ., Suita, Osaka (Japan). Dept. of Applied Chemistry

    2008-07-01

    Solid electrolytes possess important characteristics for industrial applications. Only a single ionic species can macroscopically migrate in these solids. This paper described a the new NASICON (M-Zr-Nb-P-O) type system, exhibiting an exceptionally high level of trivalent M3+ ion conductivity on polycrystalline solids. The partial substitution of the smaller higher valent Nb5+ ion for Zr4+ stabilized the NASICON phase and realized the M3+ ion conduction in the NASICON structure. It was concluded that the conductivities of the series are comparable to those of the practically applied solid electrolytes of oxide anion conductors of YSZ and CSZ. 3 refs., 2 figs.

  19. Conducting everyday life

    DEFF Research Database (Denmark)

    Juhl, Pernille

    , they are involved in preventive interventions. I conducted participatory observations with the children in their everyday life. Overall, the study stresses that even small children must be perceived as active participants who act upon and struggle with different conditions and meaning making processes across......In the paper I discuss how small children (0-4 year) develop through ‘conducting everyday life’ across contexts (Holzkamp 2013). I discuss how this process of conducting everyday life is essential when discussing the ‘good life for children’ from a child perspective. These issues are addressed...... contexts (home, day care, part-time foster family) and in relation to other co-participants....

  20. Fuzzy delay model based fault simulator for crosstalk delay fault test ...

    Indian Academy of Sciences (India)

    In this paper, a fuzzy delay model based crosstalk delay fault simulator is proposed. As design .... To find the quality of non-robust tests, a fuzzy delay ..... Dubois D and Prade H 1989 Processing Fuzzy temporal knowledge. IEEE Transactions ...

  1. Delay-dependent exponential stability of cellular neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Zhang Qiang; Wei Xiaopeng; Xu Jin

    2005-01-01

    The global exponential stability of cellular neural networks (CNNs) with time-varying delays is analyzed. Two new sufficient conditions ensuring global exponential stability for delayed CNNs are obtained. The conditions presented here are related to the size of delay. The stability results improve the earlier publications. Two examples are given to demonstrate the effectiveness of the obtained results

  2. Synchronization of delayed systems in the presence of delay time modulation

    International Nuclear Information System (INIS)

    Kye, Won-Ho; Choi, Muhan; Kim, Myung-Woon; Lee, Soo-Young; Rim, Sunghwan; Kim, Chil-Min; Park, Young-Jai

    2004-01-01

    We investigate synchronization in the presence of delay time modulation for application to communication. We have observed that the robust synchronization is established by a common delay signal and its threshold is presented using Lyapunov exponents analysis. The influence of the delay time modulation in chaotic oscillators is also discussed

  3. Persistent Memory in Single Node Delay-Coupled Reservoir Computing.

    Directory of Open Access Journals (Sweden)

    André David Kovac

    Full Text Available Delays are ubiquitous in biological systems, ranging from genetic regulatory networks and synaptic conductances, to predator/pray population interactions. The evidence is mounting, not only to the presence of delays as physical constraints in signal propagation speed, but also to their functional role in providing dynamical diversity to the systems that comprise them. The latter observation in biological systems inspired the recent development of a computational architecture that harnesses this dynamical diversity, by delay-coupling a single nonlinear element to itself. This architecture is a particular realization of Reservoir Computing, where stimuli are injected into the system in time rather than in space as is the case with classical recurrent neural network realizations. This architecture also exhibits an internal memory which fades in time, an important prerequisite to the functioning of any reservoir computing device. However, fading memory is also a limitation to any computation that requires persistent storage. In order to overcome this limitation, the current work introduces an extended version to the single node Delay-Coupled Reservoir, that is based on trained linear feedback. We show by numerical simulations that adding task-specific linear feedback to the single node Delay-Coupled Reservoir extends the class of solvable tasks to those that require nonfading memory. We demonstrate, through several case studies, the ability of the extended system to carry out complex nonlinear computations that depend on past information, whereas the computational power of the system with fading memory alone quickly deteriorates. Our findings provide the theoretical basis for future physical realizations of a biologically-inspired ultrafast computing device with extended functionality.

  4. Factors Associated with Delayed Cancer Diagnosis in Egyptian Children

    Directory of Open Access Journals (Sweden)

    E.R. Abdelkhalek

    2014-01-01

    Full Text Available Background Despite tremendous importance of early cancer diagnosis in children, few studies on this topic have been conducted in Egypt. Early stage diagnosis can have a positive effect on prognoses and the quality of life of children with cancer. We investigated delays in the diagnosis of childhood cancers in Egypt and determined the factors associated with these delays. Methods This retrospective study included 172 children with cancer from two pediatric oncology units. The interval between symptoms onset and final diagnosis for each child was estimated and examined by univariate and multivariate analyses to determine correlations with the child's sex, age at diagnosis, type and site of malignancy, family residence, socioeconomic status, and parental educational level. Findings The median total diagnosis delay period was 47 days caused by patients and/or parents (8 days and diagnosis (28 days. Statistically significant patient factors associated with delayed diagnosis were age (<5 years, lower parental education, and socioeconomic status. Sex residence and family size were not significant. Malignancy type and tumor site significantly affected the time for diagnosis. The lowest median value was associated with germ cell tumors (GCTs and leukemia, and the highest value was in children with brain tumor. Missed diagnoses were initially recorded in 39.5% of the patients and were associated with patient and tumor factors. Interpretation Delayed diagnosis of childhood cancer is related to age, family, socioeconomic status and parental education, and cancer type and site. Efforts should be made to promote awareness, develop effective steps to eliminate possible contributing factors, and determine the best intervention method.

  5. Persistent Memory in Single Node Delay-Coupled Reservoir Computing.

    Science.gov (United States)

    Kovac, André David; Koall, Maximilian; Pipa, Gordon; Toutounji, Hazem

    2016-01-01

    Delays are ubiquitous in biological systems, ranging from genetic regulatory networks and synaptic conductances, to predator/pray population interactions. The evidence is mounting, not only to the presence of delays as physical constraints in signal propagation speed, but also to their functional role in providing dynamical diversity to the systems that comprise them. The latter observation in biological systems inspired the recent development of a computational architecture that harnesses this dynamical diversity, by delay-coupling a single nonlinear element to itself. This architecture is a particular realization of Reservoir Computing, where stimuli are injected into the system in time rather than in space as is the case with classical recurrent neural network realizations. This architecture also exhibits an internal memory which fades in time, an important prerequisite to the functioning of any reservoir computing device. However, fading memory is also a limitation to any computation that requires persistent storage. In order to overcome this limitation, the current work introduces an extended version to the single node Delay-Coupled Reservoir, that is based on trained linear feedback. We show by numerical simulations that adding task-specific linear feedback to the single node Delay-Coupled Reservoir extends the class of solvable tasks to those that require nonfading memory. We demonstrate, through several case studies, the ability of the extended system to carry out complex nonlinear computations that depend on past information, whereas the computational power of the system with fading memory alone quickly deteriorates. Our findings provide the theoretical basis for future physical realizations of a biologically-inspired ultrafast computing device with extended functionality.

  6. Delays in the diagnosis and treatment of tuberculosis patients in Vietnam: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Khanh Vu T

    2007-06-01

    Full Text Available Abstract Background Treatment delay is an important indicator of access to tuberculosis diagnosis and treatment. Analyses of patient delay (i.e. time interval between onset of symptoms and first consultation of a health care provider and health care delay (i.e. time interval between first consultation and start of treatment can inform policies to improve access. This study assesses the patient, health care provider and total delay in diagnosis and treatment of new smear-positive pulmonary tuberculosis patients, and the risk factors for long delay, in Vietnam. Methods A cross-sectional survey of new patients treated by the National Tuberculosis Control Programme was conducted in 70 randomly selected districts in Vietnam. All consecutively registered patients in one quarter of 2002 were interviewed using a pre-coded structured questionnaire. Results Median (range delay was 4 weeks (1–48 for total, 3 (1–48 weeks for patient and 1 (0–25 week for health care delay. Patients with long total delay (≥ 12 weeks, 15% accounted for 49% of the cumulative number of delay-weeks. Independent risk factors (p 5 km distance from a health facility or in the northern area. For long health care delay (≥ 6 weeks this was urban setting, residence in the central area and initial visit to a communal health post, TB hospital or the private sector. Conclusion Analyses of patient and treatment delays can indicate target groups and areas for health education and strengthening of the referral system, in particular between the private sector and the NTP.

  7. Gravitational Lens Time Delays Using Polarization Monitoring

    Directory of Open Access Journals (Sweden)

    Andrew Biggs

    2017-11-01

    Full Text Available Gravitational lens time delays provide a means of measuring the expansion of the Universe at high redshift (and therefore in the ‘Hubble flow’ that is independent of local calibrations. It was hoped that many of the radio lenses found in the JVAS/CLASS survey would yield time delays as these were selected to have flat spectra and are dominated by multiple compact components. However, despite extensive monitoring with the Very Large Array (VLA, time delays have only been measured for three of these systems (out of 22. We have begun a programme to reanalyse the existing VLA monitoring data with the goal of producing light curves in polarized flux and polarization position angle, either to improve delay measurements or to find delays for new sources. Here, we present preliminary results on the lens system B1600+434 which demonstrate the presence of correlated and substantial polarization variability in each image.

  8. Controllability of nonlinear delay oscillating systems

    Directory of Open Access Journals (Sweden)

    Chengbin Liang

    2017-05-01

    Full Text Available In this paper, we study the controllability of a system governed by second order delay differential equations. We introduce a delay Gramian matrix involving the delayed matrix sine, which is used to establish sufficient and necessary conditions of controllability for the linear problem. In addition, we also construct a specific control function for controllability. For the nonlinear problem, we construct a control function and transfer the controllability problem to a fixed point problem for a suitable operator. We give a sufficient condition to guarantee the nonlinear delay system is controllable. Two examples are given to illustrate our theoretical results by calculating a specific control function and inverse of a delay Gramian matrix.

  9. Dynamics of microbubble oscillators with delay coupling

    Science.gov (United States)

    Heckman, C. R.; Sah, S. M.; Rand, R. H.

    2010-10-01

    We investigate the stability of the in-phase mode in a system of two delay-coupled bubble oscillators. The bubble oscillator model is based on a 1956 paper by Keller and Kolodner. Delay coupling is due to the time it takes for a signal to travel from one bubble to another through the liquid medium that surrounds them. Using techniques from the theory of differential-delay equations as well as perturbation theory, we show that the equilibrium of the in-phase mode can be made unstable if the delay is long enough and if the coupling strength is large enough, resulting in a Hopf bifurcation. We then employ Lindstedt's method to compute the amplitude of the limit cycle as a function of the time delay. This work is motivated by medical applications involving noninvasive localized drug delivery via microbubbles.

  10. Electrically conductive material

    Science.gov (United States)

    Singh, J.P.; Bosak, A.L.; McPheeters, C.C.; Dees, D.W.

    1993-09-07

    An electrically conductive material is described for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO[sub 2] as a matrix and 6-19 wt. % monoclinic ZrO[sub 2] formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO[sub 2] as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns. 8 figures.

  11. Conductive open frameworks

    Science.gov (United States)

    Yaghi, Omar M.; Wan, Shun; Doonan, Christian J.; Wang, Bo; Deng, Hexiang

    2018-05-22

    The disclosure relates generally to materials that comprise conductive covalent organic frameworks. The disclosure also relates to materials that are useful to store and separate gas molecules and sensors.

  12. Sodium conducting polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Skaarup, S.; West, K. (eds.)

    1989-04-01

    This section deals with the aspects of ionic conduction in general as well as specific experimental results obtained for sodium systems. The conductivity as a function of temperature and oxygen/metal ratio are given for the systems NaI, NaCF/sub 3/SO/sub 3/ and NaClO/sub 4/ plus polyethylene oxide. Attempts have been made to produce mixed phase solid electrolytes analogous to the lithium systems that have worked well. These consist of mixtures of polymer and a solid electrolyte. The addition of both nasicon and sodium beta alumina unexpectedly decreases the ionic conductivity in contrast to the lithium systems. Addition of the nonconducting silica AEROSIL in order to increase the internal surface area has the effect of retarding the phase transition at 60 deg. C, but does not enhance the conductivity. (author) 23 refs.

  13. Conductive polypropylene composites

    International Nuclear Information System (INIS)

    Koszkul, J.

    1997-01-01

    The results of studies on polypropylene composites with three sorts of Polish-made carbon blacks were presented. It was found that composite of 20% black content had properties of an electrically conducting material

  14. Complex conductivity of soils

    DEFF Research Database (Denmark)

    Revil, A.; Coperey, A.; Shao, Z.

    2017-01-01

    The complex conductivity of soil remains poorly known despite the growing importance of this method in hyrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including 4 peat samples) and one clean sand in the frequency range 0.1 Hertz...... to 45 kHz. The soil samples are saturated with 6 different NaCl brines with conductivities (0.031, 0.53, 1.15, 5.7, 14.7, and 22 S m-1, NaCl, 25°C) in order to determine their intrinsic formation factor and surface conductivity. This dataset is used to test the predictions of the dynamic Stern...

  15. Understanding Housing Delays and Relocations Within the Housing First Model.

    Science.gov (United States)

    Zerger, Suzanne; Pridham, Katherine Francombe; Jeyaratnam, Jeyagobi; Hwang, Stephen W; O'Campo, Patricia; Kohli, Jaipreet; Stergiopoulos, Vicky

    2016-01-01

    This study explores factors contributing to delays and relocations during the implementation of the Housing First model in Toronto, Ontario. While interruptions in housing tenure are expected en route to recovery and housing stability, consumer and service provider views on finding and keeping housing remain largely unknown. In-person interviews and focus groups were conducted with 48 study participants, including 23 case managers or housing workers and 25 consumers. The following three factors contributed to housing delays and transfers: (1) the effectiveness of communication and collaboration among consumers and service providers, (2) consumer-driven preferences and ambivalence, and (3) provider prioritization of consumer choice over immediate housing access. Two strategies--targeted communications and consumer engagement in housing searches--supported the housing process. Several factors affect the timing and stability of housing. Communication between and among providers and consumers, and a shared understanding of consumer choice, can further support choice and recovery.

  16. Dual-anticipating, dual and dual-lag synchronization in modulated time-delayed systems

    International Nuclear Information System (INIS)

    Ghosh, Dibakar; Chowdhury, A. Roy

    2010-01-01

    In this Letter, dual synchronization in modulated time delay system using delay feedback controller is proposed. Based on Lyapunov stability theory, we suggest a general method to achieve the dual-anticipating, dual, dual-lag synchronization of time-delayed chaotic systems and we find both its existing and sufficient stability conditions. Numerically it is shown that the dual synchronization is also possible when driving system contain two completely different systems. Effect of parameter mismatch on dual synchronization is also discussed. As an example, numerical simulations for the Mackey-Glass and Ikeda systems are conducted, which is in good agreement with the theoretical analysis.

  17. Phase delaying the human circadian clock with a single light pulse and moderate delay of the sleep/dark episode: no influence of iris color.

    Science.gov (United States)

    Canton, Jillian L; Smith, Mark R; Choi, Ho-Sun; Eastman, Charmane I

    2009-07-17

    Light exposure in the late evening and nighttime and a delay of the sleep/dark episode can phase delay the circadian clock. This study assessed the size of the phase delay produced by a single light pulse combined with a moderate delay of the sleep/dark episode for one day. Because iris color or race has been reported to influence light-induced melatonin suppression, and we have recently reported racial differences in free-running circadian period and circadian phase shifting in response to light pulses, we also tested for differences in the magnitude of the phase delay in subjects with blue and brown irises. Subjects (blue-eyed n = 7; brown eyed n = 6) maintained a regular sleep schedule for 1 week before coming to the laboratory for a baseline phase assessment, during which saliva was collected every 30 minutes to determine the time of the dim light melatonin onset (DLMO). Immediately following the baseline phase assessment, which ended 2 hours after baseline bedtime, subjects received a 2-hour bright light pulse (~4,000 lux). An 8-hour sleep episode followed the light pulse (i.e. was delayed 4 hours from baseline). A final phase assessment was conducted the subsequent night to determine the phase shift of the DLMO from the baseline to final phase assessment.Phase delays of the DLMO were compared in subjects with blue and brown irises. Iris color was also quantified from photographs using the three dimensions of red-green-blue color axes, as well as a lightness scale. These variables were correlated with phase shift of the DLMO, with the hypothesis that subjects with lighter irises would have larger phase delays. The average phase delay of the DLMO was -1.3 +/- 0.6 h, with a maximum delay of ~2 hours, and was similar for subjects with blue and brown irises. There were no significant correlations between any of the iris color variables and the magnitude of the phase delay. A single 2-hour bright light pulse combined with a moderate delay of the sleep/dark episode

  18. Phase delaying the human circadian clock with a single light pulse and moderate delay of the sleep/dark episode: no influence of iris color

    Directory of Open Access Journals (Sweden)

    Choi Ho-Sun

    2009-07-01

    Full Text Available Abstract Background Light exposure in the late evening and nighttime and a delay of the sleep/dark episode can phase delay the circadian clock. This study assessed the size of the phase delay produced by a single light pulse combined with a moderate delay of the sleep/dark episode for one day. Because iris color or race has been reported to influence light-induced melatonin suppression, and we have recently reported racial differences in free-running circadian period and circadian phase shifting in response to light pulses, we also tested for differences in the magnitude of the phase delay in subjects with blue and brown irises. Methods Subjects (blue-eyed n = 7; brown eyed n = 6 maintained a regular sleep schedule for 1 week before coming to the laboratory for a baseline phase assessment, during which saliva was collected every 30 minutes to determine the time of the dim light melatonin onset (DLMO. Immediately following the baseline phase assessment, which ended 2 hours after baseline bedtime, subjects received a 2-hour bright light pulse (~4,000 lux. An 8-hour sleep episode followed the light pulse (i.e. was delayed 4 hours from baseline. A final phase assessment was conducted the subsequent night to determine the phase shift of the DLMO from the baseline to final phase assessment. Phase delays of the DLMO were compared in subjects with blue and brown irises. Iris color was also quantified from photographs using the three dimensions of red-green-blue color axes, as well as a lightness scale. These variables were correlated with phase shift of the DLMO, with the hypothesis that subjects with lighter irises would have larger phase delays. Results The average phase delay of the DLMO was -1.3 ± 0.6 h, with a maximum delay of ~2 hours, and was similar for subjects with blue and brown irises. There were no significant correlations between any of the iris color variables and the magnitude of the phase delay. Conclusion A single 2-hour bright light

  19. Test Report Emission Test Program EPA Information Collection Request for Delayed Coking Units 736 Coker Unit

    Science.gov (United States)

    ARI Environmental, Inc. (ARI) was retained by Houston Refining LP (HRO) to conduct an emission test program at their refinery located in Houston, Texas. The testing was conducted on on the 736 Delayed Coking Unit (DCU) in response to EPA's ICR.

  20. Examining the psychosocial determinants of women's decisions to delay childbearing.

    Science.gov (United States)

    Kearney, Allison L; White, Katherine M

    2016-08-01

    What are the psychosocial determinants of women's intentions to delay childbearing until after 35 years? Attitudes, pressure from important others, perceived self-confidence and anticipated regret all influence the decision-making process of women aged 18-30 years to defer their attempts to conceive their first child until 35+ years. Research has consistently demonstrated that, for many women, the decision to delay childbearing can lead to 'unintentional childlessness' due to a failure to consider the impact of age-related fertility decline. A large body of literature has also found strong links between age-related involuntary infertility and negative psychological impacts, including an increased prevalence of anxiety, depression, guilt, stigma and poor mental health. The study initially conducted focus groups designed to ascertain important beliefs informing participants' intentions to delay childbearing. A subsequent larger-scale quantitative questionnaire followed. Participants (n = 358) were female, aged between 18 and 30 years, lived in Australia, identified as being open to the idea of having children, were heterosexual, had not already had children, were not already pregnant, and had not received a diagnosis of medical infertility prior to participating. Hierarchical multiple regression analyses showed strong support for psychosocial predictors of attitude, pressure from others and perceived self-confidence as predictors of women's intentions to delay childbearing, accounting for 59% of total variance. The extended model that included anticipated regret, accounted for a significant additional 4.4% variance in intention to delay childbearing past the age of 35 years. Proportionally more participants were younger, Caucasian, and were university students, thus limiting the generalizability of results to the wider Australian community. Future research in this domain is recommended to adopt a prospective design and incorporate a measure of behaviour to

  1. Microscopic Control Delay Modeling at Signalized Arterials Using Bluetooth Technology

    OpenAIRE

    Rajasekhar, Lakshmi

    2011-01-01

    Real-time control delay estimation is an important performance measure for any intersection to improve the signal timing plans dynamically in real-time and hence improve the overall system performance. Control delay estimates helps to determine the level-of-service (LOS) characteristics of various approaches at an intersection and takes into account deceleration delay, stopped delay and acceleration delay. All kinds of traffic delay calculation especially control delay calculation has always ...

  2. Analysis of Delayed Sea Breeze Onset for Fort Ord Prescribed Burning Operations

    Science.gov (United States)

    2015-12-01

    DELAYED SEA BREEZE ONSET FOR FORT ORD PRESCRIBED BURNING OPERATIONS by Dustin D. Hocking December 2015 Thesis Advisor: Wendell Nuss Second...AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE ANALYSIS OF DELAYED SEA BREEZE ONSET FOR FORT ORD PRESCRIBED BURNING OPERATIONS 5...release; distribution is unlimited 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) The U.S. Army conducts prescribed burns at Fort Ord

  3. On the cost/delay tradeoff of wireless delay tolerant geographic routing

    OpenAIRE

    Tasiopoulos, Argyrios; Tsiaras, Christos; Toumpis, Stavros

    2012-01-01

    In Delay Tolerant Networks (DTNs), there is a fundamental tradeoff between the aggregate transport cost of a packet and the delay in its delivery. We study this tradeoff in the context of geographical routing in wireless DTNs.We ?rst specify the optimal cost/delay tradeoff, i.e., the tradeoff under optimal network operation, using a dynamic network construction termed the Cost/Delay Evolving Graph (C/DEG) and the Optimal Cost/Delay Curve (OC/DC), a function that gives the minimum possible agg...

  4. Electrically Conductive Epoxy Adhesives

    Directory of Open Access Journals (Sweden)

    Lan Bai

    2011-02-01

    Full Text Available Conductive adhesives are widely used in electronic packaging applications such as die attachment and solderless interconnections, component repair, display interconnections, and heat dissipation. The effects of film thickness as functions of filler volume fraction, conductive filler size, shape, as well as uncured adhesive matrix viscosity on the electrical conduction behavior of epoxy-based adhesives are presented in this work. For this purpose, epoxy-based adhesives were prepared using conductive fillers of different size, shape, and types, including Ni powder, flakes, and filaments, Ag powder, and Cu powder. The filaments were 20 μm in diameter, and 160 or 260 μm in length. HCl and H3PO4 acid solutions were used to etch and remove the surface oxide layers from the fillers. The plane resistance of filled adhesive films was measured using the four-point method. In all cases of conductive filler addition, the planar resistivity levels for the composite adhesive films increased when the film thickness was reduced. The shape of resistivity-thickness curves was negative exponential decaying type and was modeled using a mathematical relation. The relationships between the conductive film resistivities and the filler volume fractions were also derived mathematically based on the experimental data. Thus, the effects of surface treatment of filler particles, the type, size, shape of fillers, and the uncured epoxy viscosity could be included empirically by using these mathematical relations based on the experimental data. By utilizing the relations we proposed to model thickness-dependent and volume fraction-dependent conduction behaviors separately, we were able to describe the combined and coupled volume fraction-film thickness relationship mathematically based on our experimental data.

  5. Fluid conductivity sensor

    International Nuclear Information System (INIS)

    Miller, F. M.

    1985-01-01

    Apparatus for sensing the electrical conductivity of fluid which can be used to detonate an electro explosive device for operating a release mechanism for uncoupling a parachute canopy from its load upon landing in water. An operating network connected to an ignition capacitor and to a conductivity sensing circuit and connected in controlling relation to a semiconductor switch has a voltage independent portion which controls the time at which the semiconductor switch is closed to define a discharge path to detonate the electro explosive device independent of the rate of voltage rise on the ignition capacitor. The operating network also has a voltage dependent portion which when a voltage of predetermined magnitude is developed on the conductivity sensing circuit in response to fluid not having the predetermined condition of conductivity, the voltage dependent portion closes the semiconductor switch to define the discharge path when the energy level is insufficient to detonate the electro explosive device. A regulated current source is connected in relation to the conductivity sensing circuit and to the electrodes thereof in a manner placing the circuit voltage across the electrodes when the conductivity of the fluid is below a predetermined magnitude so that the sensing circuit does not respond thereto and placing the circuit voltage across the sensing circuit when the conductivity of the fluid is greater than a predetermined magnitude. The apparatus is operated from a battery, and the electrodes are of dissimilar metals so selected and connected relative to the polarity portions of the circuit to maximize utilization of the battery output voltage

  6. Transparent conducting oxide nanotubes

    Science.gov (United States)

    Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Nagpal, Prashant

    2014-09-01

    Thin film or porous membranes made of hollow, transparent, conducting oxide (TCO) nanotubes, with high chemical stability, functionalized surfaces and large surface areas, can provide an excellent platform for a wide variety of nanostructured photovoltaic, photodetector, photoelectrochemical and photocatalytic devices. While large-bandgap oxide semiconductors offer transparency for incident light (below their nominal bandgap), their low carrier concentration and poor conductivity makes them unsuitable for charge conduction. Moreover, materials with high conductivity have nominally low bandgaps and hence poor light transmittance. Here, we demonstrate thin films and membranes made from TiO2 nanotubes heavily-doped with shallow Niobium (Nb) donors (up to 10%, without phase segregation), using a modified electrochemical anodization process, to fabricate transparent conducting hollow nanotubes. Temperature dependent current-voltage characteristics revealed that TiO2 TCO nanotubes, doped with 10% Nb, show metal-like behavior with resistivity decreasing from 6.5 × 10-4 Ωcm at T = 300 K (compared to 6.5 × 10-1 Ωcm for nominally undoped nanotubes) to 2.2 × 10-4 Ωcm at T = 20 K. Optical properties, studied by reflectance measurements, showed light transmittance up to 90%, within wavelength range 400 nm-1000 nm. Nb doping also improves the field emission properties of TCO nanotubes demonstrating an order of magnitude increase in field-emitter current, compared to undoped samples.

  7. Low thermal conductivity skutterudites

    Energy Technology Data Exchange (ETDEWEB)

    Fleurial, J P; Caillat, T; Borshchevsky, A

    1997-07-01

    Recent experimental results on semiconductors with the skutterudite crystal structure show that these materials possess attractive transport properties and have a good potential for achieving ZT values substantially larger than for state-of-the-art thermoelectric materials. Both n-type and p-type conductivity samples have been obtained, using several preparation techniques. Associated with a low hole effective mass, very high carrier mobilities, low electrical resistivities and moderate Seebeck coefficients are obtained in p-type skutterudites. For a comparable doping level, the carrier mobilities of n-type samples are about an order of magnitude lower than the values achieved on p-type samples. However, the much larger electron effective masses and Seebeck coefficients on p-type samples. However, the much larger electron effective masses and Seebeck coefficients make n-type skutterudite promising candidates as well. Unfortunately, the thermal conductivities of the binary skutterudites compounds are too large, particularly at low temperatures, to be useful for thermoelectric applications. Several approaches to the reduction of the lattice thermal conductivity in skutterudites are being pursued: heavy doping, formation of solid solutions and alloys, study of novel ternary and filled skutterudite compounds. All those approaches have already resulted in skutterudite compositions with substantially lower thermal conductivity values in these materials. Recently, superior thermoelectric properties in the moderate to high temperature range were achieved for compositions combining alloying and filling of the skutterudite structure. Experimental results and mechanisms responsible for low thermal conductivity in skutterudites are discussed.

  8. N-methyl-d-aspartate receptors, learning and memory: chronic intraventricular infusion of the NMDA receptor antagonist d-AP5 interacts directly with the neural mechanisms of spatial learning.

    Science.gov (United States)

    Morris, R G M; Steele, R J; Bell, J E; Martin, S J

    2013-03-01

    Three experiments were conducted to contrast the hypothesis that hippocampal N-methyl-d-aspartate (NMDA) receptors participate directly in the mechanisms of hippocampus-dependent learning with an alternative view that apparent impairments of learning induced by NMDA receptor antagonists arise because of drug-induced neuropathological and/or sensorimotor disturbances. In experiment 1, rats given a chronic i.c.v. infusion of d-AP5 (30 mm) at 0.5 μL/h were selectively impaired, relative to aCSF-infused animals, in place but not cued navigation learning when they were trained during the 14-day drug infusion period, but were unimpaired on both tasks if trained 11 days after the minipumps were exhausted. d-AP5 caused sensorimotor disturbances in the spatial task, but these gradually worsened as the animals failed to learn. Histological assessment of potential neuropathological changes revealed no abnormalities in d-AP5-treated rats whether killed during or after chronic drug infusion. In experiment 2, a deficit in spatial learning was also apparent in d-AP5-treated rats trained on a spatial reference memory task involving two identical but visible platforms, a task chosen and shown to minimise sensorimotor disturbances. HPLC was used to identify the presence of d-AP5 in selected brain areas. In Experiment 3, rats treated with d-AP5 showed a delay-dependent deficit in spatial memory in the delayed matching-to-place protocol for the water maze. These data are discussed with respect to the learning mechanism and sensorimotor accounts of the impact of NMDA receptor antagonists on brain function. We argue that NMDA receptor mechanisms participate directly in spatial learning. © 2013 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  9. Reward acts as a signal to control delay-period activity in delayed-response tasks.

    Science.gov (United States)

    Ichihara-Takeda, Satoe; Takeda, Kazuyoshi; Funahashi, Shintaro

    2010-03-31

    Prefrontal delay-period activity represents a neural mechanism for the active maintenance of information and needs to be controlled by some signal to appropriately operate working memory. To examine whether reward-delivery acts as this signal, the effects of delay-period activity in response to unexpected reward-delivery were examined by analyzing single-neuron activity recorded in the primate dorsolateral prefrontal cortex. Among neurons that showed delay-period activity, 34% showed inhibition of this activity in response to unexpected reward-delivery. The delay-period activity of these neurons was affected by the expectation of reward-delivery. The strength of the reward signal in controlling the delay-period activity is related to the strength of the effect of reward information on the delay-period activity. These results indicate that reward-delivery acts as a signal to control delay-period activity.

  10. Chaos synchronization in time-delayed systems with parameter mismatches and variable delay times

    International Nuclear Information System (INIS)

    Shahverdiev, E.M.; Nuriev, R.A.; Hashimov, R.H.; Shore, K.A.

    2004-06-01

    We investigate synchronization between two undirectionally linearly coupled chaotic nonidentical time-delayed systems and show that parameter mismatches are of crucial importance to achieve synchronization. We establish that independent of the relation between the delay time in the coupled systems and the coupling delay time, only retarded synchronization with the coupling delay time is obtained. We show that with parameter mismatch or without it neither complete nor anticipating synchronization occurs. We derive existence and stability conditions for the retarded synchronization manifold. We demonstrate our approach using examples of the Ikeda and Mackey Glass models. Also for the first time we investigate chaos synchronization in time-delayed systems with variable delay time and find both existence and sufficient stability conditions for the retarded synchronization manifold with the coupling-delay lag time. (author)

  11. Delays in Building Construction Projects in Ghana

    Directory of Open Access Journals (Sweden)

    Adwoa B Agyakwah-Baah

    2010-07-01

    Full Text Available This study investigates the causes of delay of building construction projects in Ghana to determine the most important according to the key project participants; clients, consultants, and contractors. Thirty-two possible causes of delay were identified from the literature and semi-structured interviews of 15 key players in the implementation process. These delay factors were further categorised into nine major groups. The list of delay causes was subjected to a questionnaire survey for the identification of the most important causes of delay. The field survey included 130 respondents made up of 39 contractors, 37 clients and 54 consultants. The relative importance of the individual causes and the groups were calculated and ranked by their relative importance index. The overall results of the study indicate that the respondents generally agree that financial group factors ranked highest among the major factors causing delay in construction projects in Ghana. The financial group factors were delay in honouring payment certificates, difficulty in accessing credit and fluctuation in prices. Materials group factors are second followed by scheduling and controlling factors.

  12. Behavioral effects of delayed timeouts from reinforcement.

    Science.gov (United States)

    Byrne, Tom; Poling, Alan

    2017-03-01

    Timeouts are sometimes used in applied settings to reduce target responses, and in some circumstances delays are unavoidably imposed between the onset of a timeout and the offset of the response that produces it. The present study examined the effects of signaled and unsignaled timeouts in rats exposed to concurrent fixed-ratio 1 fixed-ratio 1 schedules of food delivery, where each response on one lever, the location of which changed across conditions, produced both food and a delayed 10-s timeout. Delays of 0 to 38 s were examined. Delayed timeouts often, but not always, substantially reduced the number of responses emitted on the lever that produced timeouts relative to the number emitted on the lever that did not produce timeouts. In general, greater sensitivity was observed to delayed timeouts when they were signaled. These results demonstrate that delayed timeouts, like other delayed consequences, can affect behavior, albeit less strongly than immediate consequences. © 2017 Society for the Experimental Analysis of Behavior.

  13. Responsible conduct of research

    CERN Document Server

    Shamoo, Adil E

    2015-01-01

    Since the early 2000s, the field of Responsible Conduct of Research has become widely recognized as essential to scientific education, investigation, and training. At present, research institutions with public funding are expected to have some minimal training and education in RCR for their graduate students, fellows and trainees. These institutions also are expected to have a system in place for investigating and reporting misconduct in research or violations of regulations in research with human subjects, or in their applications to federal agencies for funding. Public scrutiny of the conduct of scientific researchers remains high. Media reports of misconduct scandals, biased research, violations of human research ethics rules, and moral controversies in research occur on a weekly basis. Since the 2009 publication of the 2nd edition of Shamoo and Resnik's Responsible Conduct of Research, there has been a vast expansion in the information, knowledge, methods, and diagnosis of problems related to RCR and the ...

  14. Representing delayed force feedback as a combination of current and delayed states.

    Science.gov (United States)

    Avraham, Guy; Mawase, Firas; Karniel, Amir; Shmuelof, Lior; Donchin, Opher; Mussa-Ivaldi, Ferdinando A; Nisky, Ilana

    2017-10-01

    To adapt to deterministic force perturbations that depend on the current state of the hand, internal representations are formed to capture the relationships between forces experienced and motion. However, information from multiple modalities travels at different rates, resulting in intermodal delays that require compensation for these internal representations to develop. To understand how these delays are represented by the brain, we presented participants with delayed velocity-dependent force fields, i.e., forces that depend on hand velocity either 70 or 100 ms beforehand. We probed the internal representation of these delayed forces by examining the forces the participants applied to cope with the perturbations. The findings showed that for both delayed forces, the best model of internal representation consisted of a delayed velocity and current position and velocity. We show that participants relied initially on the current state, but with adaptation, the contribution of the delayed representation to adaptation increased. After adaptation, when the participants were asked to make movements with a higher velocity for which they had not previously experienced with the delayed force field, they applied forces that were consistent with current position and velocity as well as delayed velocity representations. This suggests that the sensorimotor system represents delayed force feedback using current and delayed state information and that it uses this representation when generalizing to faster movements. NEW & NOTEWORTHY The brain compensates for forces in the body and the environment to control movements, but it is unclear how it does so given the inherent delays in information transmission and processing. We examined how participants cope with delayed forces that depend on their arm velocity 70 or 100 ms beforehand. After adaptation, participants applied opposing forces that revealed a partially correct representation of the perturbation using the current and the

  15. Quantized Majorana conductance

    Science.gov (United States)

    Zhang, Hao; Liu, Chun-Xiao; Gazibegovic, Sasa; Xu, Di; Logan, John A.; Wang, Guanzhong; van Loo, Nick; Bommer, Jouri D. S.; de Moor, Michiel W. A.; Car, Diana; Op Het Veld, Roy L. M.; van Veldhoven, Petrus J.; Koelling, Sebastian; Verheijen, Marcel A.; Pendharkar, Mihir; Pennachio, Daniel J.; Shojaei, Borzoyeh; Lee, Joon Sue; Palmstrøm, Chris J.; Bakkers, Erik P. A. M.; Sarma, S. Das; Kouwenhoven, Leo P.

    2018-04-01

    Majorana zero-modes—a type of localized quasiparticle—hold great promise for topological quantum computing. Tunnelling spectroscopy in electrical transport is the primary tool for identifying the presence of Majorana zero-modes, for instance as a zero-bias peak in differential conductance. The height of the Majorana zero-bias peak is predicted to be quantized at the universal conductance value of 2e2/h at zero temperature (where e is the charge of an electron and h is the Planck constant), as a direct consequence of the famous Majorana symmetry in which a particle is its own antiparticle. The Majorana symmetry protects the quantization against disorder, interactions and variations in the tunnel coupling. Previous experiments, however, have mostly shown zero-bias peaks much smaller than 2e2/h, with a recent observation of a peak height close to 2e2/h. Here we report a quantized conductance plateau at 2e2/h in the zero-bias conductance measured in indium antimonide semiconductor nanowires covered with an aluminium superconducting shell. The height of our zero-bias peak remains constant despite changing parameters such as the magnetic field and tunnel coupling, indicating that it is a quantized conductance plateau. We distinguish this quantized Majorana peak from possible non-Majorana origins by investigating its robustness to electric and magnetic fields as well as its temperature dependence. The observation of a quantized conductance plateau strongly supports the existence of Majorana zero-modes in the system, consequently paving the way for future braiding experiments that could lead to topological quantum computing.

  16. Conducting metal dithiolate complexes

    DEFF Research Database (Denmark)

    Underhill, A. E.; Ahmad, M. M.; Turner, D. J.

    1985-01-01

    Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound......Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound...

  17. Transmission delays in hardware clock synchronization

    Science.gov (United States)

    Shin, Kang G.; Ramanathan, P.

    1988-01-01

    Various methods, both with software and hardware, have been proposed to synchronize a set of physical clocks in a system. Software methods are very flexible and economical but suffer an excessive time overhead, whereas hardware methods require no time overhead but are unable to handle transmission delays in clock signals. The effects of nonzero transmission delays in synchronization have been studied extensively in the communication area in the absence of malicious or Byzantine faults. The authors show that it is easy to incorporate the ideas from the communication area into the existing hardware clock synchronization algorithms to take into account the presence of both malicious faults and nonzero transmission delays.

  18. A continuous time Cournot duopoly with delays

    International Nuclear Information System (INIS)

    Gori, Luca; Guerrini, Luca; Sodini, Mauro

    2015-01-01

    This paper extends the classical repeated duopoly model with quantity-setting firms of Bischi et al. (1998) by assuming that production of goods is subject to some gestation lags but exchanges take place continuously in the market. The model is expressed in the form of differential equations with discrete delays. By using some recent mathematical techniques and numerical experiments, results show some dynamic phenomena that cannot be observed when delays are absent. In addition, depending on the extent of time delays and inertia, synchronisation failure can arise even in the event of homogeneous firms.

  19. Delayed encephalopathy after acute carbon monoxide poisoning

    Directory of Open Access Journals (Sweden)

    Mehmet İbrahim Turan

    2014-03-01

    Full Text Available Carbon monoxide poisoning is a major cause of death following attempted suicide and accidental exposures. Although clinical presentation depends on the duration and the intensity of exposure, the assessment of the severity of intoxication is difficult. A small percentage of patients who show complete initial recovery may develop delayed neurological deficits. Delayed encephalopathy after acute carbon monoxide poisoning is a rare and poor prognosis neurologic disorders and there is no specific treatment. We present a case with early onset of delayed encephalopathy after acute carbon monoxide poisoning with typical cranial imaging findings in a child with atypical history and clinical presentation.

  20. Bubbling in delay-coupled lasers.

    Science.gov (United States)

    Flunkert, V; D'Huys, O; Danckaert, J; Fischer, I; Schöll, E

    2009-06-01

    We theoretically study chaos synchronization of two lasers which are delay coupled via an active or a passive relay. While the lasers are synchronized, their dynamics is identical to a single laser with delayed feedback for a passive relay and identical to two delay-coupled lasers for an active relay. Depending on the coupling parameters the system exhibits bubbling, i.e., noise-induced desynchronization, or on-off intermittency. We associate the desynchronization dynamics in the coherence collapse and low-frequency fluctuation regimes with the transverse instability of some of the compound cavity's antimodes. Finally, we demonstrate how, by using an active relay, bubbling can be suppressed.

  1. Travelling wave solutions in delayed cooperative systems

    International Nuclear Information System (INIS)

    Li, Bingtuan; Zhang, Liang

    2011-01-01

    We establish the existence of travelling wave solutions for delayed cooperative recursions that are allowed to have more than two equilibria. We define an important extended real number that is used to determine the speeds of travelling wave solutions. The results can be applied to a large class of delayed cooperative reaction–diffusion models. We show that for a delayed Lotka–Volterra reaction–diffusion competition model, there exists a finite positive number c * + that can be characterized as the slowest speed of travelling wave solutions connecting two mono-culture equilibria or connecting a mono-culture with the coexistence equilibrium

  2. Transcriptional delay stabilizes bistable gene networks.

    Science.gov (United States)

    Gupta, Chinmaya; López, José Manuel; Ott, William; Josić, Krešimir; Bennett, Matthew R

    2013-08-02

    Transcriptional delay can significantly impact the dynamics of gene networks. Here we examine how such delay affects bistable systems. We investigate several stochastic models of bistable gene networks and find that increasing delay dramatically increases the mean residence times near stable states. To explain this, we introduce a non-Markovian, analytically tractable reduced model. The model shows that stabilization is the consequence of an increased number of failed transitions between stable states. Each of the bistable systems that we simulate behaves in this manner.

  3. Conducting Educational Design Research

    Science.gov (United States)

    McKenney, Susan; Reeves, Thomas

    2012-01-01

    Educational design research blends scientific investigation with systematic development and implementation of solutions to educational problems. Empirical investigation is conducted in real learning settings--not laboratories--to craft usable and effective solutions. At the same time, the research is carefully structured to produce theoretical…

  4. Conductance eigenchannels in nanocontacts

    DEFF Research Database (Denmark)

    Brandbyge, Mads; Sørensen, Mads Reinholdt; Jacobsen, Karsten Wedel

    1997-01-01

    The electronic conductance of metal nanocontacts is analyzed in terms of eigenchannels for the transmission. The transmission through individual eigenchannels is calculated numerically for realistic models of gold point contacts based on molecular-dynamics simulation of the elongation of a contac...

  5. Conduct Disorder and Comorbidity.

    Science.gov (United States)

    Stahl, Nicole D.; Clarizio, Harvey F.

    1999-01-01

    Provides critical examination of research published during past ten years addressing Conduct Disorder (CD), Attention Deficit Hyperactivity Disorder, Oppositional Defiant Disorder (ODD), and internalizing disorders. Concludes comorbidity varies with age, gender, informant, diagnostic criteria, and nature of the sample. Implications of comorbidity…

  6. CERN Code of Conduct

    CERN Document Server

    Department, HR

    2010-01-01

    The Code is intended as a guide in helping us, as CERN contributors, to understand how to conduct ourselves, treat others and expect to be treated. It is based around the five core values of the Organization. We should all become familiar with it and try to incorporate it into our daily life at CERN.

  7. High Thermal Conductivity Materials

    CERN Document Server

    Shinde, Subhash L

    2006-01-01

    Thermal management has become a ‘hot’ field in recent years due to a need to obtain high performance levels in many devices used in such diverse areas as space science, mainframe and desktop computers, optoelectronics and even Formula One racing cars! Thermal solutions require not just taking care of very high thermal flux, but also ‘hot spots’, where the flux densities can exceed 200 W/cm2. High thermal conductivity materials play an important role in addressing thermal management issues. This volume provides readers a basic understanding of the thermal conduction mechanisms in these materials and discusses how the thermal conductivity may be related to their crystal structures as well as microstructures developed as a result of their processing history. The techniques for accurate measurement of these properties on large as well as small scales have been reviewed. Detailed information on the thermal conductivity of diverse materials including aluminum nitride (AlN), silicon carbide (SiC), diamond, a...

  8. Transient Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of transient heat conduction.Fourier's law. General heat conducation equation. Thermal diffusivity. Biot and Fourier numbers. Lumped analysis and time constant. Semi-infinite body: fixed surface temperature, convective heat transfer at the surface, or constant surface heat flux...

  9. Pressure dependence of conductivity

    International Nuclear Information System (INIS)

    Bracewell, B.L.; Hochheimer, H.D.

    1993-01-01

    The overall objectives of this work were to attempt the following: (1) Measure the pressure dependence of the electrical conductivity of several quasi-one-dimensional, charge-density-wave solids, including measurements along various crystal directions. (2) Measure photocurrents in selected MX solids at ambient and elevated pressures. (3) Measure the resonance Raman spectra for selected MX solids as a function of pressure

  10. New code of conduct

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    During his talk to the staff at the beginning of the year, the Director-General mentioned that a new code of conduct was being drawn up. What exactly is it and what is its purpose? Anne-Sylvie Catherin, Head of the Human Resources (HR) Department, talked to us about the whys and wherefores of the project.   Drawing by Georges Boixader from the cartoon strip “The World of Particles” by Brian Southworth. A code of conduct is a general framework laying down the behaviour expected of all members of an organisation's personnel. “CERN is one of the very few international organisations that don’t yet have one", explains Anne-Sylvie Catherin. “We have been thinking about introducing a code of conduct for a long time but lacked the necessary resources until now”. The call for a code of conduct has come from different sources within the Laboratory. “The Equal Opportunities Advisory Panel (read also the "Equal opportuni...

  11. Quantized Majorana conductance

    NARCIS (Netherlands)

    Zhang, Hao; Liu, Chun Xiao; Gazibegovic, Sasa; Xu, Di; Logan, John A.; Wang, Guanzhong; Van Loo, Nick; Bommer, Jouri D.S.; De Moor, Michiel W.A.; Car, Diana; Op Het Veld, Roy L.M.; Van Veldhoven, Petrus J.; Koelling, Sebastian; Verheijen, Marcel A.; Pendharkar, Mihir; Pennachio, Daniel J.; Shojaei, Borzoyeh; Lee, Joon Sue; Palmstrøm, Chris J.; Bakkers, Erik P.A.M.; Sarma, S. Das; Kouwenhoven, Leo P.

    2018-01-01

    Majorana zero-modes - a type of localized quasiparticle - hold great promise for topological quantum computing. Tunnelling spectroscopy in electrical transport is the primary tool for identifying the presence of Majorana zero-modes, for instance as a zero-bias peak in differential conductance. The

  12. Conductive polymer composition

    NARCIS (Netherlands)

    2010-01-01

    The present invention relates to a process for the preparation of a conductive polymer composition comprising graphene and the articles obtained by this process. The process comprises the following steps: A) contacting graphite oxide in an aqueous medium with a water-soluble or dispersible

  13. Factores de riesgo asociados para el desarrollo de hemorragia intraventricular en recién nacidos < 1500 g ingresados a una UCIN

    Directory of Open Access Journals (Sweden)

    M.Á. Segura-Roldán

    2017-12-01

    Full Text Available Resumen: Introducción: La hemorragia peri-intraventricular (HIV es la complicación neurológica más importante de la prematurez, con alteraciones en el neurodesarrollo a largo plazo. El objetivo del trabajo fue describir los factores de riesgo asociados a la HIV en neonatos < 1500 g al nacer que ingresaron a la UCIN. Material y métodos: Se realizó un estudio de cohorte de prematuros < 1500 g ingresados a la UCIN en 2016, con seguimiento hasta su egreso, a domicilio o por defunción. Se analizaron variables perinatales y neonatales. Para el análisis estadístico se comparó los que desarrollaron HIV y los que no la desarrollaron con las pruebas t de Student y Chi-cuadrado; se calculó la razón de momios (RM y las diferencias de medias (DM con intervalo de confianza del 95%. Resultados: Ingresaron 135 pacientes y 45 desarrollaron HIV (33.3%: HIV I (n = 22; 16%, HIV II (n = 6; 4.4%, HIV III (n = 8; 5.9% y HIV IV (n = 9; 6.6%. La cesárea fue protector RM: 0.18; IC 95%: 0.07-0.45 para el desarrollo de HIV. La mortalidad fue mayor en los neonatos con HIV: RM: 4.63, IC 95%: 1.76-12.11. El peso al nacer fue menor en los que tuvieron HIV (887 vs. 979 g, así como la edad gestacional (28.1 vs. 29.26, en la HIV III/IV la mortalidad fue del 64.7% y para las HIV I/II del 10.7% (p = 0.0006. Conclusiones: La HIV es una enfermedad presente en pacientes < 1500 g, sobre todo en los de menor peso y edad gestacional. Las HIV severas se asociaron a una mayor mortalidad. Abstract: Introduction: Intraventricular haemorrhage (IVH is the most frequent neurological complication of the premature infant, and is associated with an adverse neurological outcome. The objective of this study was to identify risk factors associated with IVH in preterm infants less than 1500 g in the NICU. Material and methods: A cohort of preterm infants less than 1500 g, admitted to the NICU during 2016

  14. OSCILLATION OF NONLINEAR DELAY DIFFERENCE EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper deals with the oscillatory properties of a class of nonlinear difference equations with several delays. Sufficient criteria in the form of infinite sum for the equations to be oscillatory are obtained.

  15. Compensating for telecommunication delays during robotic telerehabilitation.

    Science.gov (United States)

    Consoni, Leonardo J; Siqueira, Adriano A G; Krebs, Hermano I

    2017-07-01

    Rehabilitation robotic systems may afford better care and telerehabilitation may extend the use and benefits of robotic therapy to the home. Data transmissions over distance are bound by intrinsic communication delays which can be significant enough to deem the activity unfeasible. Here we describe an approach that combines unilateral robotic telerehabilitation and serious games. This approach has a modular and distributed design that permits different types of robots to interact without substantial code changes. We demonstrate the approach through an online multiplayer game. Two users can remotely interact with each other with no force exchanges, while a smoothing and prediction algorithm compensates motions for the delay in the Internet connection. We demonstrate that this approach can successfully compensate for data transmission delays, even when testing between the United States and Brazil. This paper presents the initial experimental results, which highlight the performance degradation with increasing delays as well as improvements provided by the proposed algorithm, and discusses planned future developments.

  16. Isolation Effect in Immediate and Delayed Recall

    Science.gov (United States)

    Bellezza, Francis S.; Cheney, Terry L.

    1973-01-01

    If the hypothesis of selective rehearsal is used to account for the isolation effect, then the recall of isolated items will depend both on the serial position of the isolated item and on whether recall is immediate or delayed. (Author)

  17. A simple chaotic delay differential equation

    International Nuclear Information System (INIS)

    Sprott, J.C.

    2007-01-01

    The simplest chaotic delay differential equation with a sinusoidal nonlinearity is described, including the route to chaos, Lyapunov exponent spectrum, and chaotic diffusion. It is prototypical of many other high-dimensional chaotic systems

  18. Time delay of quantum scattering processes

    International Nuclear Information System (INIS)

    Martin, P.A.

    1981-01-01

    The author presents various aspects of the theory of the time delay of scattering processes. The author mainly studies non-relativistic two-body scattering processes, first summarizing briefly the theory of simple scattering systems. (Auth.)

  19. Does Bilingualism Delay the Development of Dementia?

    Directory of Open Access Journals (Sweden)

    Amy L Atkinson

    2016-08-01

    Full Text Available It has been suggested that bilingualism (where individuals speak two languages may delay the development of dementia. However, much of the research is inconclusive. Some researchers have reported that bilingualism delays the onset and diagnosis of dementia, whilst other studies have found weak or even detrimental effects. This paper reviews a series of nine empirical studies, published up until March 2016, which investigated whether bilingualism significantly delays the onset of dementia. The article also explores whether the inconsistent findings can be attributed to differences in study designs or the definitions of bilingualism used between studies. Based on current evidence, it appears that lifelong bilingualism, where individuals frequently use both languages, may be protective against dementia. However, becoming bilingual in adulthood or using the second language infrequently is unlikely to substantially delay onset of the disease.

  20. Rich dynamics of discrete delay ecological models

    International Nuclear Information System (INIS)

    Peng Mingshu

    2005-01-01

    We study multiple bifurcations and chaotic behavior of a discrete delay ecological model. New form of chaos for the 2-D map is observed: the combination of potential period doubling and reverse period-doubling leads to cascading bubbles

  1. Four-channel delay generator model 5740

    International Nuclear Information System (INIS)

    Baumatz, D.; Milner, M.

    1978-01-01

    The 4-channel delay generator model 5740 generates 4-pulse groups in independent channels. The device offers the possibility of controlling both the time intervals between the pulses of a group and the rate of generation of groups

  2. Lauch of CERN particle accelerator delayed

    CERN Multimedia

    2007-01-01

    "Scientists seeking to uncover the secrets of the universe will have to wait a little longer after the CERN laboratory inSwitzerland yesterday confirmed a delay in tests of its massive new particle accelerator." (1 page)

  3. Diagnosis delay in tuberculosis and its consequences

    International Nuclear Information System (INIS)

    Habibullah, S.; Sheikh, M.A.; Sadiq, A.; Anwar, T.

    2004-01-01

    Objective: To find out the average duration from onset of symptoms to the diagnosis and treatment of tuberculosis, reasons for diagnostic delay, its consequences, association of variables and formulation of recommendations. Results: In this study it was found that average time from onset of initial symptoms to diagnosis and treatment of tuberculosis was 120 days. In 64% of the patients medical practitioners were responsible for delaying the diagnosis of tuberculosis. Loss of weight in 40% and haemoptysis is 21% were the consequences of diagnostic delay of tuberculosis. Delay in the diagnosis of tuberculosis was statistically significant in those patients who consulted private practitioners, and consequences of tuberculosis were severe in those patients who consulted late. (author)

  4. Variable Delay in port-Hamiltonian Telemanipulation

    NARCIS (Netherlands)

    Secchi, C; Stramigioli, Stefano; Fantuzzi, C.

    2006-01-01

    In several applications involving bilateral telemanipulation, master and slave act at different power scales. In this paper a strategy for passively dealing with variable communication delay in scaled port-Hamiltonian based telemanipulation over packet switched networks is proposed.

  5. Nanostructured conductive polymeric materials

    Science.gov (United States)

    Al-Saleh, Mohammed H.

    Conductive polymer composites (CPCs) are a suitable alternative to metals in many applications due to their light-weight, corrosion resistance, low cost, ease of processing and design flexibility. CPCs have been formulated using different types of conductive fillers. In this PhD thesis, the focus is on CPCs for electrostatic discharge (ESD) protection and electromagnetic interference (EMI) attenuation. Despite the versatility of conductive fillers, carbon black (CB) has been the dominant filler to make CPCs for ESD protection applications because CB/polymer composites have a cost advantage over all other CPCs. For EMI shielding, stainless steel fibres and metal coated fibers are the preferred fillers, however CPCs made of those fibers are not the dominant EMI shielding materials. Metal coated and polymer plated polymers are the most widely used EMI shielding options. The limited use of CPCs in the EMI shielding market is because the high filler loading required to formulate a composite with an adequate level of shielding remarkably increases the composite price. In order to increase the competitiveness of CPCs, percolation threshold should be minimized as much as possible and composites with high EMI shielding capabilities at low filler loading should be formulated because all conductive fillers are expensive compared to polymers. In this thesis, two different methodologies to reduce percolation threshold in CPCs have been successfully developed and a CPC with exceptional EMI shielding capability has been formulated using copper nanowires as conductive filler. The first percolation threshold reduction technique is based on the selective localization of CB at the interface of immiscible polymer blend. The technique requires adding a copolymer that prefers the blend's interface and for which CB nanoparticles has the highest affinity. The second method is based on producing a CPC powder and then using this powder as a conductive filler to produce composite by dry

  6. Nonlinear Cournot duopoly with implementation delays

    International Nuclear Information System (INIS)

    Matsumoto, Akio; Szidarovszky, Ferenc

    2015-01-01

    We study the effects of two delays on the local as well as on global stability of nonlinear Cournot duopoly dynamics. The two major findings are an analytical construction of the stability switching curve on which stability is lost and the numerical confirmation of the birth of aperiodic global dynamics when the stationary state is locally unstable. The delays matters and can generate various dynamics ranging from simple to complicated dynamics.

  7. Delay in polling systems in heavy traffic

    Science.gov (United States)

    van der Mei, Robert D.

    1998-10-01

    We study the delay in asymmetric cyclic polling systems with general mixtures of gated and exhaustive service, with generally distributed service times and switch-over times, in heavy traffic. We obtain closed-form expressions for all moments of the delay incurred at each of the queues. The expressions are strikingly simple and can even be expressed as finite products of known factors. The results provide new insights into the heavy-traffic behavior of polling systems.

  8. Acceptable Channel Switching Delays for Mobile TV

    DEFF Research Database (Denmark)

    Fleury, Alexandre; Pedersen, Jakob Schou; Larsen, Lars Bo

    2011-01-01

    as well as three potential effect factors: the transition type, the test environment and the audiovisual content. The results show that delays longer than 5.7 seconds annoyed test participants, and that the transition type had a significant impact on the rating of channel switching delays. However......, neither the test environment nor the audiovisual content influenced the ratings significantly. Finally, a discussion of these results and directions for future research are proposed....

  9. Inverse Problems for Nonlinear Delay Systems

    Science.gov (United States)

    2011-03-15

    population dynamics. We consider the delay between birth and adulthood for neonate pea aphids and present a mathematical model that treats this delay as...which there is currently no known cure. For HIV, the core of the virus is composed of single-stranded viral RNA and protein components. As depicted in...at a CD4 receptor site and the viral core is injected into the cell. Once inside, the protein components enable transcription and integration of the

  10. The Strategic Perils of Delayed Differentiation

    OpenAIRE

    Krishnan S. Anand; Karan Girotra

    2007-01-01

    The value of delayed differentiation (also known as postponement) for a monopolist has been extensively studied in the operations literature. We analyze the case of (imperfectly) competitive markets with demand uncertainty, wherein the choice of supply chain configuration (i.e., early or delayed differentiation) is endogenous to the competing firms. We characterize firms' choices in equilibrium and analyze the effects of these choices on quantities sold, profits, consumer surplus, and welfare...

  11. Diagnosis delay in Libyan female breast cancer

    Directory of Open Access Journals (Sweden)

    Ermiah Eramah

    2012-08-01

    Full Text Available Abstract Aims To study the diagnosis delay and its impact on stage of disease among women with breast cancer on Libya. Methods 200 women, aged 22 to 75 years with breast cancer diagnosed during 2008–2009 were interviewed about the period from the first symptoms to the final histological diagnosis of breast cancer. This period (diagnosis time was categorized into 3 periods: 6 months. If diagnosis time was longer than 3 months, the diagnosis was considered delayed (diagnosis delay. Consultation time was the time taken to visit the general practitioner after the first symptoms. Retrospective preclinical and clinical data were collected on a form (questionnaire during an interview with each patient and from medical records. Results The median of diagnosis time was 7.5 months. Only 30.0% of patients were diagnosed within 3 months after symptoms. 14% of patients were diagnosed within 3–6 months and 56% within a period longer than 6 months. A number of factors predicted diagnosis delay: Symptoms were not considered serious in 27% of patients. Alternative therapy (therapy not associated with cancer was applied in 13.0% of the patients. Fear and shame prevented the visit to the doctor in 10% and 4.5% of patients, respectively. Inappropriate reassurance that the lump was benign was an important reason for prolongation of the diagnosis time. Diagnosis delay was associated with initial breast symptom(s that did not include a lump (p  Diagnosis delay was associated with bigger tumour size (p Conclusions Diagnosis delay is very serious problem in Libya. Diagnosis delay was associated with complex interactions between several factors and with advanced stages. There is a need for improving breast cancer awareness and training of general practitioners to reduce breast cancer mortality by promoting early detection. The treatment guidelines should pay more attention to the early phases of breast cancer. Especially, guidelines for good practices in managing

  12. Time delay in a multichannel formalism

    International Nuclear Information System (INIS)

    Haberzettl, Helmut; Workman, Ron

    2007-01-01

    We reexamine the time-delay formalism of Wigner, Eisenbud, and Smith, which was developed to analyze both elastic and inelastic resonances. An error in the paper of Smith has propagated through the literature. We correct this error and show how the results of Eisenbud and Smith are related. We also comment on some recent time-delay studies, based on Smith's erroneous interpretation of the Eisenbud result

  13. Identification of optimal inspection interval via delay-time concept

    Directory of Open Access Journals (Sweden)

    Glauco Ricardo Simões Gomes

    2016-06-01

    Full Text Available This paper presents an application of mathematical modeling aimed at managing maintenance based on the delay-time concept. The study scenario was the manufacturing sector of an industrial unit, which operates 24 hours a day in a continuous flow of production. The main idea was to use the concepts of this approach to determine the optimal time of preventive action by the maintenance department in order to ensure the greatest availability of equipment and facilities at appropriate maintenance costs. After a brief introduction of the subject, the article presents topics that illustrate the importance of mathematical modeling in maintenance management and the delay-time concept. It also describes the characteristics of the company where the study was conducted, as well as the data related to the production process and maintenance actions. Finally, the results obtained after applying the delay-time concept are presented and discussed, as well as the limitations of the article and the proposals for future research.

  14. Emergency surgery pre-operative delays - realities and economic impacts.

    Science.gov (United States)

    O'Leary, D P; Beecher, S; McLaughlin, R

    2014-12-01

    A key principle of acute surgical service provision is the establishment of a distinct patient flow process and an emergency theatre. Time-to-theatre (TTT) is a key performance indicator of theatre efficiency. The combined impacts of an aging population, increasing demands and complexity associated with centralisation of emergency and oncology services has placed pressure on emergency theatre access. We examined our institution's experience with running a designated emergency theatre for acute surgical patients. A retrospective review of an electronic prospectively maintained database was performed between 1/1/12 and 31/12/13. A cost analysis was conducted to assess the economic impact of delayed TTT, with every 24hr delay incurring the cost of an additional overnight bed. Delays and the economic effects were assessed only after the first 24 h as an in-patient had elapsed. In total, 7041 procedures were performed. Overall mean TTT was 26 h, 2 min. There were significant differences between different age groups, with those aged under 16 year and over 65 having mean TTT at 6 h, 34 min (95% C.I. 0.51-2.15, p 65 years age group had a mean TTT of 23 h, 41 min which was significantly longer than the overall mean TTT Vascular and urological emergencies are significantly disadvantaged in competition with other services for a shared emergency theatre. The economic impact of delayed TTT was calculated at €7,116,000, or €9880/day of additional costs generated from delayed TTT over a 24 month period. One third of patients waited longer than 24 h for emergency surgery, with the elderly disproportionately represented in this group. Aside from the clinical risks of delayed and out of hours surgery, such practices incur significant additional costs. New strategies must be devised to ensure efficient access to emergency theatres, investment in such services is likely to be financially and clinically beneficial. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier

  15. Transparent Conductive Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-06-22

    The objectives of this program between UT-Battelle, LLC (the ''Contractor'') and (Battelle Memorial Institute) (the "Participant") were directed towards achieving significant improvement: in the electrical conductivity and optical/infrared transmission of single-wall carbon nanotube (SWNT)-based composite materials. These materials will be used in coating applications that range from aircraft canopies to display applications. The goal of the project was to obtain supported mats of SWNTs with sheet conductivities approaching 10 ohms/square combined with high optical transmission (>85% transmission at 550 nm), thereby permitting their application as a replacement for indium tin oxide (ITO) in a variety of applications such as flexible displays.

  16. Super ionic conductive glass

    Science.gov (United States)

    Susman, S.; Volin, K.J.

    Described is an ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A/sub 1 + x/D/sub 2-x/3/Si/sub x/P/sub 3 - x/O/sub 12 - 2x/3/, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  17. Conducting Polymer Based Nanobiosensors

    Directory of Open Access Journals (Sweden)

    Chul Soon Park

    2016-06-01

    Full Text Available In recent years, conducting polymer (CP nanomaterials have been used in a variety of fields, such as in energy, environmental, and biomedical applications, owing to their outstanding chemical and physical properties compared to conventional metal materials. In particular, nanobiosensors based on CP nanomaterials exhibit excellent performance sensing target molecules. The performance of CP nanobiosensors varies based on their size, shape, conductivity, and morphology, among other characteristics. Therefore, in this review, we provide an overview of the techniques commonly used to fabricate novel CP nanomaterials and their biosensor applications, including aptasensors, field-effect transistor (FET biosensors, human sense mimicking biosensors, and immunoassays. We also discuss prospects for state-of-the-art nanobiosensors using CP nanomaterials by focusing on strategies to overcome the current limitations.

  18. 'Stuffed' conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; Chen, Jun; West, Keld

    2005-01-01

    Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid. In the pres......Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid....... In the present work we demonstrate this principle on three different CP's: polypyrrole (PPy), poly-terthiophene (PTTh) and poly(3,4-ethylenedioxy thiophene) (PEDT), using ferrocene as a model molecule to be trapped in the polymer films. (c) 2005 Elsevier Ltd. All rights reserved....

  19. dq-Frame Cascaded Delayed Signal Cancellation-Based PLL

    DEFF Research Database (Denmark)

    Golestan, Saeed; Ramezani, Malek; Guerrero, Josep M.

    2015-01-01

    on their position in the PLL structure. Inspired from the concept of delayed signal cancellation (DSC), the idea of cascaded DSC (CDSC) has recently been introduced as an effective solution to improve the performance of the PLL under adverse grid conditions. However, the focus has been on the application of CDSC...... operator as the pre-filtering stage of PLL, and little work has been conducted on its application as the in-loop filtering stage of PLL. This paper provides a detailed analysis and design of dqCDSC-PLL (PLL with in-loop dq-frame CDSC operator). The study is started with an overview of this PLL...

  20. The reasons for delay lumbar puncture

    Directory of Open Access Journals (Sweden)

    MH. Lotfi

    2017-04-01

    Full Text Available Early diagnosis of meningitis and encephalitis and prompt initiation of appropriate therapy is vital and any delay will lead to high mortality and serious and permanent morbidity. The main purpose of this study was to evaluate the management of 220 patients with suspected central nervous system (CNS infections (meningitis and encephalitis to determine the percentage of patients’ suspected CNS infection undergo lumbar puncture in acceptable time (in accordance with conventional algorithms. In this descriptive study, patients with suspected CNS infections admitted to Bu-Ali and Qods hospitals, in the period July 2013 to December 2015 were studied. Information of 220 patients was collected. Continuous variables were summarized as means ± standard deviation and categorical variables as frequencies and percentages. Lumbar puncture (LP in patients was delayed in 200 cases (91%. Most common causes of delay in performing LP were prolongation of the process of determining patient needs to puncture, satisfying patients, CT scan delay and the delay in allowing LP by neurologist. In this study, delaying LP rate was higher than other studies. It seems certain pattern in assistants’ visits for counseling. CT requests and neurologic consultation before LP performed for all adult patients.

  1. Nuclear size and cell division delay

    International Nuclear Information System (INIS)

    Bird, R.P.

    1986-01-01

    Radiation-induced division delay has been linked to damage at the nuclear envelope. Further, cells in G 2 phase are drastically arrested by high LET radiation such that single particles traversing cell nuclei may produce measurable division delay. A modest effort was initiated using two related cell lines of different size, near-diploid cells and near-tetraploid cells of Chinese hamster origin, to compare their sensitivity for radiation-induced division delay. If the nuclear surface is the critical target, then a larger nuclear cross-section presented to an alpha-particle beam should exhibit delay induced by a lesser particle fluence. Preliminary estimates of the extent of delay in asynchronous cultures following low doses of gamma-irradiation or of alpha-irradiation were made by in-situ observation of the time of onset of mitosis and by fixation and staining of cultures to determine the mitotic index as a function of time after irradiation. The basic approach to evaluating division delay will be to use Colecemid to accumulate mitotic cells over a period of time

  2. The Limitations to Delay-Insensitivity in Asynchronous Circuits

    National Research Council Canada - National Science Library

    Martin, Alain J

    1990-01-01

    ... produced are delay-insensitive (DI). A digital circuit is DI when its correct operation is independent of the delays in operators and in the wires connecting the operators, except that the delays are finite and positive...

  3. Lag synchronization of chaotic systems with time-delayed linear ...

    Indian Academy of Sciences (India)

    delayed linear terms via impulsive control is investigated. Based on the stability theory of impulsive delayed differen- tial equations, some sufficient conditions are obtained guaranteeing the synchronized behaviours between two delayed chaotic ...

  4. Conducting interactive experiments online.

    Science.gov (United States)

    Arechar, Antonio A; Gächter, Simon; Molleman, Lucas

    2018-01-01

    Online labor markets provide new opportunities for behavioral research, but conducting economic experiments online raises important methodological challenges. This particularly holds for interactive designs. In this paper, we provide a methodological discussion of the similarities and differences between interactive experiments conducted in the laboratory and online. To this end, we conduct a repeated public goods experiment with and without punishment using samples from the laboratory and the online platform Amazon Mechanical Turk. We chose to replicate this experiment because it is long and logistically complex. It therefore provides a good case study for discussing the methodological and practical challenges of online interactive experimentation. We find that basic behavioral patterns of cooperation and punishment in the laboratory are replicable online. The most important challenge of online interactive experiments is participant dropout. We discuss measures for reducing dropout and show that, for our case study, dropouts are exogenous to the experiment. We conclude that data quality for interactive experiments via the Internet is adequate and reliable, making online interactive experimentation a potentially valuable complement to laboratory studies.

  5. Virtual unit delay for digital frequency adaptive T/4 delay phase-locked loop system

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    /processor with a fixed sampling rate considering the cost and complexity, where the number of unit delays that have been adopted should be an integer. For instance, in conventional digital control systems, a single-phase T/4 Delay Phase-Locked Loop (PLL) system takes 50 unit delays (i.e., in a 50-Hz system...... Delay PLL system should be done in its implementation. This process will result in performance degradation in the digital control system, as the exactly required number of delays is not realized. Hence, in this paper, a Virtual Unit Delay (VUD) has been proposed to address such challenges to the digital......Digital micro-controllers/processors enable the cost-effective control of grid-connected power converter systems in terms of system monitoring, signal processing (e.g., grid synchronization), control (e.g., grid current and voltage control), etc. Normally, the control is implemented in a micro-controller...

  6. Time Delay and Associated Factors in Diagnosis and Treatment of Pulmonary Tuberculosis in Markazi Province

    Directory of Open Access Journals (Sweden)

    Aliasghar Farazi

    2012-07-01

    Full Text Available Introduction: Delay in the diagnosis of tuberculosis increases the risk of death and enhances the transmission of disease in the community. This study aims to determine the patient and health service delay and factors affecting it in tuberculosis diagnosis. Materials & Methods: A cross-sectional survey that included all the public health centers was conducted in Markazi province from March 2009 till June 2011. Patients were interviewed after diagnosis by using a structured questionnaire. Results: One hundred and sixty-six patients aged between 9 and 87 (median; 66 years were included in the study. They comprised 87 (52.4% females and 79 (47.6% males. The median and mean of patient delay was 35 and 62 days, respectively; the median and mean of health system diagnosis delay was 34 and 53 days, respectively; the median and mean of health system treatment delay was 5 and 6 days, respectively; The median and mean of total delays were 86 and 121 days, respectively for all patients. The main determinants of delay were non education, poor economic, private sector, female gender and age≥55. Conclusion: The results of this review suggest that there is a need for revising case-finding strategies and reduction of infectious cases for better control of tuberculosis.

  7. Determinants of developmental delay in infants aged 12 months.

    Science.gov (United States)

    Slykerman, Rebecca F; Thompson, John M D; Clark, Phillipa M; Becroft, David M O; Robinson, Elizabeth; Pryor, Jan E; Wild, Chris J; Mitchell, Edwin A

    2007-03-01

    The aim of this study was to determine which demographic, maternal, obstetric and postnatal variables were associated with achievement of developmental milestones at the age of 12 months in term infants. Mothers and babies were enrolled in the Auckland Birthweight Collaborative Study shortly after birth. All infants were full term (gestation >or= 37 weeks). Approximately half of the sample were small for gestational age (SGA = birthweight 10th percentile). A maternal interview was conducted soon after birth. Phase 2 of the study occurred 12 months later when mothers were sent a postal questionnaire requesting information about the child's health and development during the first year of life using the Denver Prescreening Developmental Questionnaire. Seven hundred and forty-four (85.4%) European mothers returned the postal questionnaire. SGA children were not at increased risk of developmental delay at 12 months of age. In a sample representative of New Zealand European children, after adjustment for the effects of potential confounders, maternal smoking during pregnancy (OR = 2.1 [95% CI 1.1, 4.0]), maternal smoking during the first year of life (OR = 1.9 [95% CI 1.0, 3.8]) and low levels of satisfaction with parenting (OR = 2.4 [95% CI 1.1, 5.2]) were associated with significantly increased risk of developmental delay. In the subgroup of SGA children, maternal smoking during pregnancy (OR = 2.9 [95% CI 1.4, 6.2]), high levels of stress associated with parenting (OR = 2.2 [95% CI 1.2, 4.0]), and low levels of satisfaction with parenting (OR = 4.3 [95% CI 1.3, 13.5]) were significantly associated with developmental delay after adjustment for the effects of potential confounders. In conclusion, maternal and postnatal factors were better predictors of developmental delay than demographic variables.

  8. Improving Delay-Range-Dependent Stability Condition for Systems with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Wei Qian

    2013-01-01

    Full Text Available This paper discusses the delay-range-dependent stability for systems with interval time-varying delay. Through defining the new Lyapunov-Krasovskii functional and estimating the derivative of the LKF by introducing new vectors, using free matrices and reciprocally convex approach, the new delay-range-dependent stability conditions are obtained. Two well-known examples are given to illustrate the less conservatism of the proposed theoretical results.

  9. Leveraging delay discounting for health: Can time delays influence food choice?

    Science.gov (United States)

    Appelhans, Bradley M; French, Simone A; Olinger, Tamara; Bogucki, Michael; Janssen, Imke; Avery-Mamer, Elizabeth F; Powell, Lisa M

    2018-03-15

    Delay discounting, the tendency to choose smaller immediate rewards over larger delayed rewards, is theorized to promote consumption of immediately rewarding but unhealthy foods at the expense of long-term weight maintenance and nutritional health. An untested implication of delay discounting models of decision-making is that selectively delaying access to less healthy foods may promote selection of healthier (immediately available) alternatives, even if they may be less desirable. The current study tested this hypothesis by measuring healthy versus regular vending machine snack purchasing before and during the implementation of a 25-s time delay on the delivery of regular snacks. Purchasing was also examined under a $0.25 discount on healthy snacks, a $0.25 tax on regular snacks, and the combination of both pricing interventions with the 25-s time delay. Across 32,019 vending sales from three separate vending locations, the 25-s time delay increased healthy snack purchasing from 40.1% to 42.5%, which was comparable to the impact of a $0.25 discount (43.0%). Combining the delay and the discount had a roughly additive effect (46.0%). However, the strongest effects were seen under the $0.25 tax on regular snacks (53.7%) and the combination of the delay and the tax (50.2%). Intervention effects varied substantially between vending locations. Importantly, time delays did not harm overall vending sales or revenue, which is relevant to the real-world feasibility of this intervention. More investigation is needed to better understand how the impact of time delays on food choice varies across populations, evaluate the effects of time delays on beverage vending choices, and extend this approach to food choices in contexts other than vending machines. ClinicalTrials.gov, NCT02359916. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Derivation and computation of discrete-delay and continuous-delay SDEs in mathematical biology.

    Science.gov (United States)

    Allen, Edward J

    2014-06-01

    Stochastic versions of several discrete-delay and continuous-delay differential equations, useful in mathematical biology, are derived from basic principles carefully taking into account the demographic, environmental, or physiological randomness in the dynamic processes. In particular, stochastic delay differential equation (SDDE) models are derived and studied for Nicholson's blowflies equation, Hutchinson's equation, an SIS epidemic model with delay, bacteria/phage dynamics, and glucose/insulin levels. Computational methods for approximating the SDDE models are described. Comparisons between computational solutions of the SDDEs and independently formulated Monte Carlo calculations support the accuracy of the derivations and of the computational methods.

  11. Global synchronization criteria with channel time-delay for chaotic time-delay system

    International Nuclear Information System (INIS)

    Sun Jitao

    2004-01-01

    Based on the Lyapunov stabilization theory, matrix measure, and linear matrix inequality (LMIs), this paper studies the chaos synchronization of time-delay system using the unidirectional linear error feedback coupling with time-delay. Some generic conditions of chaos synchronization with time-delay in the transmission channel is established. The chaotic Chua's circuit is used for illustration, where the coupling parameters are determined according to the criteria under which the global chaos synchronization of the time-delay coupled systems is achieved

  12. The discourse of health managers on aspects related to the delay in tuberculosis diagnosis

    Directory of Open Access Journals (Sweden)

    Lenilde Duarte de Sa

    2013-10-01

    Full Text Available The aim of this study was to analyze the discourse of health managers on aspects related to delay in tuberculosis diagnosis. This was a qualitative research study, conducted with 16 Family Health Unit managers. The empirical data were obtained through semi-structured interviews. The analysis was based on the theoretical framework of the French school of discourse analysis. According to the managers’ statements, the delay in tuberculosis diagnosis is related to patient and health service aspects. As for patient aspects, managers report fear, prejudice and lack of information as factors that may promote a delayed diagnosis. Regarding health service aspects, structural problems and lack of professional skills were reported. The discourse of managers should be considered to qualify tuberculosis control actions and to prevent delays in diagnosis.

  13. Deriving cochlear delays in humans using otoacoustic emissions and auditory evoked potentials

    DEFF Research Database (Denmark)

    Pigasse, Gilles

    A great deal of the processing of incoming sounds to the auditory system occurs within the cochlear. The organ of Corti within the cochlea has differing mechanical properties along its length that broadly gives rise to frequency selectivity. Its stiffness is at maximum at the base and decreases...... relation between frequency and travel time in the cochlea defines the cochlear delay. This delay is directly associated with the signal analysis occurring in the inner ear and is therefore of primary interest to get a better knowledge of this organ. It is possible to estimate the cochlear delay by direct...... and invasive techniques, but these disrupt the normal functioning of the cochlea and are usually conducted in animals. In order to obtain an estimate of the cochlear delay that is closer to the normally functioning human cochlea, the present project investigates non-invasive methods in normal hearing adults...

  14. Thermal contact conductance

    CERN Document Server

    Madhusudana, Chakravarti V

    2013-01-01

    The work covers both theoretical and practical aspects of thermal contact conductance. The theoretical discussion focuses on heat transfer through spots, joints, and surfaces, as well as the role of interstitial materials (both planned and inadvertent). The practical discussion includes formulae and data that can be used in designing heat-transfer equipment for a variety of joints, including special geometries and configurations. All of the material has been updated to reflect the latest advances in the field.

  15. Impulsive control of time-delay systems using delayed impulse and its application to impulsive master-slave synchronization

    International Nuclear Information System (INIS)

    Sun Jitao; Han Qinglong; Jiang Xiefu

    2008-01-01

    This Letter is concerned with impulsive control of a class of nonlinear time-delay systems. Some uniform stability criteria for the closed-loop time-delay system under delayed impulsive control are derived by using piecewise Lyapunov functions. Then the criteria are applied to impulsive master-slave synchronization of some secure communication systems with transmission delays and sample delays under delayed impulsive control. Two numerical examples are given to illustrate the effectiveness of the derived results

  16. Conducting carbonized polyaniline nanotubes

    International Nuclear Information System (INIS)

    Mentus, Slavko; Ciric-Marjanovic, Gordana; Trchova, Miroslava; Stejskal, Jaroslav

    2009-01-01

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min -1 up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 μm, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 μm, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm -1 , increased to 0.7 S cm -1 upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  17. Conducting carbonized polyaniline nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Mentus, Slavko; Ciric-Marjanovic, Gordana [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Trchova, Miroslava; Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Square 2, 162 06 Prague 6 (Czech Republic)], E-mail: gordana@ffh.bg.ac.rs

    2009-06-17

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min{sup -1} up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 {mu}m, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 {mu}m, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm{sup -1}, increased to 0.7 S cm{sup -1} upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  18. Radiative thermal conduction fronts

    International Nuclear Information System (INIS)

    Borkowski, K.J.; Balbus, S.A.; Fristrom, C.C.

    1990-01-01

    The discovery of the O VI interstellar absorption lines in our Galaxy by the Copernicus observatory was a turning point in our understanding of the Interstellar Medium (ISM). It implied the presence of widespread hot (approx. 10 to the 6th power K) gas in disk galaxies. The detection of highly ionized species in quasi-stellar objects' absorption spectra may be the first indirect observation of this hot phase in external disk galaxies. Previous efforts to understand extensive O VI absorption line data from our Galaxy were not very successful in locating the regions where this absorption originates. The location at interfaces between evaporating ISM clouds and hot gas was favored, but recent studies of steady-state conduction fronts in spherical clouds by Ballet, Arnaud, and Rothenflug (1986) and Bohringer and Hartquist (1987) rejected evaporative fronts as the absorption sites. Researchers report here on time-dependent nonequilibrium calculations of planar conductive fronts whose properties match well with observations, and suggest reasons for the difference between the researchers' results and the above. They included magnetic fields in additional models, not reported here, and the conclusions are not affected by their presence

  19. Facilitating tolerance of delayed reinforcement during functional communication training.

    Science.gov (United States)

    Fisher, W W; Thompson, R H; Hagopian, L P; Bowman, L G; Krug, A

    2000-01-01

    Few clinical investigations have addressed the problem of delayed reinforcement. In this investigation, three individuals whose destructive behavior was maintained by positive reinforcement were treated using functional communication training (FCT) with extinction (EXT). Next, procedures used in the basic literature on delayed reinforcement and self-control (reinforcer delay fading, punishment of impulsive responding, and provision of an alternative activity during reinforcer delay) were used to teach participants to tolerate delayed reinforcement. With the first case, reinforcer delay fading alone was effective at maintaining low rates of destructive behavior while introducing delayed reinforcement. In the second case, the addition of a punishment component reduced destructive behavior to near-zero levels and facilitated reinforcer delay fading. With the third case, reinforcer delay fading was associated with increases in masturbation and head rolling, but prompting and praising the individual for completing work during the delay interval reduced all problem behaviors and facilitated reinforcer delay fading.

  20. Delayed neutrons in liquid metal spallation targets

    International Nuclear Information System (INIS)

    Ridikas, D.; Bokov, P.; David, J.C.; Dore, D.; Giacri, M.L.; Van Lauwe, A.; Plukiene, R.; Plukis, A.; Ignatiev, S.; Pankratov, D.

    2003-01-01

    The next generation spallation neutron sources, neutrino factories or RIB production facilities currently being designed and constructed around the world will increase the average proton beam power on target by a few orders of magnitude. Increased proton beam power results in target thermal hydraulic issues leading to new target designs, very often based on flowing liquid metal targets such as Hg, Pb, Pb-Bi. Radioactive nuclides produced in liquid metal targets are transported into hot cells, past electronics, into pumps with radiation sensitive components, etc. Besides the considerable amount of photon activity in the irradiated liquid metal, a significant amount of the delayed neutron precursor activity can be accumulated in the target fluid. The transit time from the front of a liquid metal target into areas, where delayed neutrons may be important, can be as short as a few seconds, well within one half-life of many delayed neutron precursors. Therefore, it is necessary to evaluate the total neutron flux (including delayed neutrons) as a function of time and determine if delayed neutrons contribute significantly to the dose rate. In this study the multi-particle transport code MCNPX combined with the material evolution program CINDER'90 will be used to evaluate the delayed neutron flux and spectra. The following scientific issues will be addressed in this paper: - Modeling of a typical geometry of the liquid metal spallation target; - Predictions of the prompt neutron fluxes, fission fragment and spallation product distributions; - Comparison of the above parameters with existing experimental data; - Time-dependent calculations of delayed neutron precursors; - Neutron flux estimates due to the prompt and delayed neutron emission; - Proposal of an experimental program to measure delayed neutron spectra from high energy spallation-fission reactions. The results of this study should be directly applicable in the design study of the European MegaPie (1 MW

  1. Factors associated with delays in treatment initiation after tuberculosis diagnosis in two districts of India.

    Directory of Open Access Journals (Sweden)

    Durba Paul

    Full Text Available BACKGROUND: Excessive time between diagnosis and initiation of tuberculosis (TB treatment contributes to ongoing TB transmission and should be minimized. In India, Revised National TB Control Programme (RNTCP focuses on indicator start of treatment within 7 days of diagnosis for patients with sputum smear-positive PTB for monitoring DOTS implementation. OBJECTIVES: To determine length of time between diagnosis and initiation of treatment and factors associated with delays of more than 7 days in smear-positive pulmonary TB. METHODS: Using existing programme records such as the TB Register, treatment cards, and the laboratory register, we conducted a retrospective cohort study of all patients with smear-positive pulmonary TB registered from July-September 2010 in two districts in India. A random sample of patients with pulmonary TB who experienced treatment delay of more than 7 days was interviewed using structured questionnaire. RESULTS: 2027 of 3411 patients registered with pulmonary TB were smear-positive. 711(35% patients had >7 days between diagnosis and treatment and 262(13% had delays >15 days. Mean duration between TB diagnosis and treatment initiation was 8 days (range = 0-128 days. Odds of treatment delay >7 days was 1.8 times more likely among those who had been previously treated (95% confidence interval [CI] 1.5-2.3 and 1.6 (95% CI 1.3-1.8 times more likely among those diagnosed in health facilities without microscopy centers. The main factors associated with a delay >7 days were: patient reluctance to start a re-treatment regimen, patients seeking second opinions, delay in transportation of drugs to the DOT centers and delay in initial home visits. To conclude, treatment delay >7 days was associated with a number of factors that included history of previous treatment and absence of TB diagnostic services in the local health facility. Decentralized diagnostic facilities and improved referral procedures may reduce such treatment

  2. Survival analysis for predictive factors of delay vaccination in Iranian children

    Directory of Open Access Journals (Sweden)

    Abolfazl Mohammadbeigi

    2015-01-01

    Full Text Available Background: Today, beside immunization coverage the age appropriate vaccination is another helpful index in public health. Evidences have shown that high immunization coverage rates do not necessarily imply age-appropriate vaccination status. The current study aimed to show the predictive factors of delayed vaccination by survival models. Methods: A historical cohort study conducted on 3610 children aged between 24 and 47 months who was living in the suburbs of five big cities of Iran. Time of delay in vaccination of first dose of mumps-measles-rubella (MMR was calculated from date of vaccination minus age appropriate time according to vaccine card. Kaplan-Maier and Log rank tests were used for comparison the median of delay time. For controlling of confounding variables, multivariate cox model was used and hazard ratio with 95% confidence interval (95% was reported. Results: The mean ± standard deviation and median interquartile range of delay time was 38.34 ± 73.1 and 16 (11-31 days in delayed group. The Log rank test showed that city of living, nationality, parents′ education, and birth order are related with prolonged delay time in MMR vaccination (P 0.05. Cox regression showed that city of living, mother education, and nationality are the most predictive factors of delay time duration in MMR vaccination. Conclusions: Delay time duration of vaccination increased by faring from capital to the east south. Moreover, concentration of foreign immigrants in big cities and low level of mother education are the most predictors of delayed vaccination. Educational intervention should focus on immigrants and mothers with low education level.

  3. Evaluation of electrical propagation delay with cardiomyocytes by photosensitization reaction in vitro

    Science.gov (United States)

    Doi, Marika; Ogawa, Emiyu; Arai, Tsunenori

    2017-02-01

    In order to study cardiomyocyte electrical conduction damage by a photosensitization reaction (PR) mostly comes from outside of the cells in a few minutes after the PR, we studied propagation delay of contact action potential with cardiomyocyte by the PR. To determine appropriate PR condition for tachyarrhythmia ablation, a precise electrophysiological experiment in vitro has been preferable. We measured the contact action potential using a microelectrode array system of which information may be correct than conventional Ca2+ measurement. We investigated the propagation delays of an evoked potential to evaluate the electrical conduction damage by the PR. Rat cardiomyocytes were cultivated for 5-7 days on a dish with which 64 electrodes were patterned, in an incubator controlled to 37°C, 5% CO2. The following conditions were used for the PR: 40 μg/ml talapordfin sodium and 290 mW/cm2, 40-78 J/cm2 for an irradiation. A 2D map was obtained to visualize the propagation delays of the evoked potential. The propagation speed, which was calculated based on the measured propagation delays, was decreased by about 30-50% on average of all electrodes after the PR. Therefore, we think 2D propagation delays measurement of the evoked potential with contact action potential measuring system might be available to evaluate the acute electrical conduction damage of cardiomyocyte by the PR.

  4. Data Assimilation by delay-coordinate nudging

    Science.gov (United States)

    Pazo, Diego; Lopez, Juan Manuel; Carrassi, Alberto

    2016-04-01

    A new nudging method for data assimilation, delay-coordinate nudging, is presented. Delay-coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time-step. Numerical experiments with a low order chaotic system show that the new method systematically outperforms standard nudging in different model and observational scenarios, also when using an un-optimized formulation of the delay-nudging coefficients. A connection between the optimal delay and the dominant Lyapunov exponent of the dynamics is found based on heuristic arguments and is confirmed by the numerical results, providing a guideline for the practical implementation of the algorithm. Delay-coordinate nudging preserves the easiness of implementation, the intuitive functioning and the reduced computational cost of the standard nudging, making it a potential alternative especially in the field of seasonal-to-decadal predictions with large Earth system models that limit the use of more sophisticated data assimilation procedures.

  5. Television viewing associates with delayed language development.

    Science.gov (United States)

    Chonchaiya, Weerasak; Pruksananonda, Chandhita

    2008-07-01

    To identify impact of television viewing on language development. The case-control study included 56 new patients with language delay and 110 normal children, aged 15-48 months. Language delay was diagnosed by reviewing language milestones and Denver-II. Television viewing variables and child/parental characteristics between both groups were interviewed. The data were analyzed by ANOVA and chi-square test. Adjusted odds ratios and 95% confidence intervals were calculated from multivariate logistic regression model. Forty-six boys and 10 girls; mean [+/-SD] age, 2.11+/-0.47 years of the case group and 59 boys and 51 girls; mean [+/-SD] age, 2.23+/-0.80 years of the control group were enrolled. Children who had language delay usually started watching television earlier at age 7.22+/-5.52 months vs. 11.92+/-5.86 months, p-valuetelevision than normal children (3.05+/-1.90 h/day vs. 1.85+/-1.18 h/day; p-valuetelevision attelevision>2 h/day were approximately six times more likely to have language delays. There is a relationship between early onset and high frequency of TV viewing and language delay.

  6. Theory of attosecond delays in molecular photoionization.

    Science.gov (United States)

    Baykusheva, Denitsa; Wörner, Hans Jakob

    2017-03-28

    We present a theoretical formalism for the calculation of attosecond delays in molecular photoionization. It is shown how delays relevant to one-photon-ionization, also known as Eisenbud-Wigner-Smith delays, can be obtained from the complex dipole matrix elements provided by molecular quantum scattering theory. These results are used to derive formulae for the delays measured by two-photon attosecond interferometry based on an attosecond pulse train and a dressing femtosecond infrared pulse. These effective delays are first expressed in the molecular frame where maximal information about the molecular photoionization dynamics is available. The effects of averaging over the emission direction of the electron and the molecular orientation are introduced analytically. We illustrate this general formalism for the case of two polyatomic molecules. N 2 O serves as an example of a polar linear molecule characterized by complex photoionization dynamics resulting from the presence of molecular shape resonances. H 2 O illustrates the case of a non-linear molecule with comparably simple photoionization dynamics resulting from a flat continuum. Our theory establishes the foundation for interpreting measurements of the photoionization dynamics of all molecules by attosecond metrology.

  7. Time delay interferometry with moving spacecraft arrays

    International Nuclear Information System (INIS)

    Tinto, Massimo; Estabrook, F.B.; Armstrong, J.W.

    2004-01-01

    Space-borne interferometric gravitational wave detectors, sensitive in the low-frequency (millihertz) band, will fly in the next decade. In these detectors the spacecraft-to-spacecraft light-travel-times will necessarily be unequal, time varying, and (due to aberration) have different time delays on up and down links. The reduction of data from moving interferometric laser arrays in solar orbit will in fact encounter nonsymmetric up- and down-link light time differences that are about 100 times larger than has previously been recognized. The time-delay interferometry (TDI) technique uses knowledge of these delays to cancel the otherwise dominant laser phase noise and yields a variety of data combinations sensitive to gravitational waves. Under the assumption that the (different) up- and down-link time delays are constant, we derive the TDI expressions for those combinations that rely only on four interspacecraft phase measurements. We then turn to the general problem that encompasses time dependence of the light-travel times along the laser links. By introducing a set of noncommuting time-delay operators, we show that there exists a quite general procedure for deriving generalized TDI combinations that account for the effects of time dependence of the arms. By applying our approach we are able to re-derive the 'flex-free' expression for the unequal-arm Michelson combinations X 1 , and obtain the generalized expressions for the TDI combinations called relay, beacon, monitor, and symmetric Sagnac

  8. Investigation of delayed fission gas release

    International Nuclear Information System (INIS)

    Cayet, Nicolas

    1996-05-01

    The study of the fission gas release process in the high burnup rig IFA-562 has revealed a particular fuel behaviour: a delay in the fission gas release process. It appeared that an important release of gas was measured by the pressure transducers once the power had decreased, whereas, during steady-state operation, the pressure did not increase very much. After examinations, the gap size has been concluded to be the main parameter involving this delay. However the burnup could have been a potential factor, its role is mainly to close the gap by swelling. The observations of low burnup rods have shown the same delayed fission gas release, the gap being small by design and closed essentially by thermal expansion. The study of the kinetics has demonstrated the time-independency of the phenomenon. Thus the proposed mechanism driving this delayed fission gas release would involve three consecutives stages. During steady-state, the gas is released into the interlinkage network of grain boundary bubbles and cracks. Due to the closed gap, the gas is trapped in some void volumes, unable to escape the pellet. During power reduction, the gap and some old/new cracks open, immediately providing a path for the gas to the pressure transducers and explaining this delay in the fission gas release. (author)

  9. Conducting polyamine nanocomposites development

    International Nuclear Information System (INIS)

    Nascimento, R.C.; Maciel, T.C.G.L.; Guimaraes, M.J.O.C.; Garcia, M.E.F.

    2010-01-01

    Polymeric nanocomposites are hybrid materials formed by the combination of inorganic nanoparticles dispersed in a polymeric matrix with, at least, one dimension in the nanometer range. It was used as nanoparticles layered and tubular clay minerals, and its insertion and dispersion were conducted through the in situ polymerization technique. As the polymer matrix, it was utilized a polyamine, which, later, will be inserted in a polyacrylamide gel for the development of a compound that aggregates both main characteristics. The nanocomposites were prepared in different polymerization conditions (temperature, concentration and nanoparticle type) and characterized by XRD and FTIR. It was observed that regarding the polymerization conditions, the temperature had influence on the kind of material obtained and on the reaction speed; the type of nanoparticle affected its interaction with the polymer matrix, predominantly providing the formation of nanocomposites by the intercalation mechanism in the layered clay. (author)

  10. Ion-conducting membranes

    Science.gov (United States)

    Masel, Richard I.; Sajjad, Syed Dawar; Gao, Yan; Liu, Zengcai; Chen, Qingmei

    2017-12-26

    An anion-conducting polymeric membrane comprises a terpolymer of styrene, vinylbenzyl-R.sub.s and vinylbenzyl-R.sub.x. R.sub.s is a positively charged cyclic amine group. R.sub.x is at least one constituent selected from the group consisting Cl, OH and a reaction product between an OH or Cl and a species other than a simple amine or a cyclic amine. The total weight of the vinylbenzyl-R.sub.x groups is greater than 0.3% of the total weight of the membrane. In a preferred embodiment, the membrane is a Helper Membrane that increases the faradaic efficiency of an electrochemical cell into which the membrane is incorporated, and also allows product formation at lower voltages than in cells without the Helper Membrane.

  11. Universal mesoscopic conductance fluctuations

    International Nuclear Information System (INIS)

    Evangelou, S.N.

    1992-01-01

    The theory of conductance fluctuations in disordered metallic systems with size large compared to the mean free path of the electron but small compared to localization length is considered. It is demonstrates that fluctuations have an universal character and are due to repulsion between levels and spectral rigidity. The basic fluctuation measures for the energy spectrum in the mesoscopic regime of disordered systems are consistent with the Gaussian random matrix ensemble predictions. Although our disordered electron random matrix ensemble does not belong to the Gaussian ensemble the two ensembles turn out to be essentially similar. The level repulsion and the spectral rigidity found in nuclear spectra should also be observed in the metallic regime of Anderson localization. 7 refs. (orig.)

  12. Communication key using delay times in time-delayed chaos synchronization

    International Nuclear Information System (INIS)

    Kim, Chil-Min; Kye, Won-Ho; Rim, Sunghwan; Lee, Soo-Young

    2004-01-01

    We propose an efficient key scheme, which can generate a great number of communication keys, for communication using chaos synchronization. We have attained the keys from delay times of time-delay coupled chaotic systems. We explain the scheme and the efficiency by coupling Henon and logistic maps and illustrate them by coupling Navier-Stokes and Lorenz equations as a continuous system

  13. Time-delayed autosynchronous swarm control.

    Science.gov (United States)

    Biggs, James D; Bennet, Derek J; Dadzie, S Kokou

    2012-01-01

    In this paper a general Morse potential model of self-propelling particles is considered in the presence of a time-delayed term and a spring potential. It is shown that the emergent swarm behavior is dependent on the delay term and weights of the time-delayed function, which can be set to induce a stationary swarm, a rotating swarm with uniform translation, and a rotating swarm with a stationary center of mass. An analysis of the mean field equations shows that without a spring potential the motion of the center of mass is determined explicitly by a multivalued function. For a nonzero spring potential the swarm converges to a vortex formation about a stationary center of mass, except at discrete bifurcation points where the center of mass will periodically trace an ellipse. The analytical results defining the behavior of the center of mass are shown to correspond with the numerical swarm simulations.

  14. Positive mood effects on delay discounting.

    Science.gov (United States)

    Hirsh, Jacob B; Guindon, Alex; Morisano, Dominique; Peterson, Jordan B

    2010-10-01

    Delay discounting is the process by which the value of an expected reward decreases as the delay to obtaining that reward increases. Individuals with higher discounting rates tend to prefer smaller immediate rewards over larger delayed rewards. Previous research has indicated that personality can influence an individual's discounting rates, with higher levels of Extraversion predicting a preference for immediate gratification. The current study examined how this relationship would be influenced by situational mood inductions. While main effects were observed for both Extraversion and cognitive ability in the prediction of discounting rates, a significant interaction was also observed between Extraversion and positive affect. Extraverted individuals were more likely to prefer an immediate reward when first put in a positive mood. Extraverts thus appear particularly sensitive to impulsive, incentive-reward-driven behavior by temperament and by situational factors heightening positive affect. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

  15. Delays in the management of retroperitoneal sarcomas

    DEFF Research Database (Denmark)

    Seinen, Jojanneke; Almquist, Martin; Styring, Emelie

    2010-01-01

    Retroperitoneal sarcomas are rare and treatment should optimally be centralized. Despite successful centralization with 90% of the patients referred prior to surgery, delays occur, which led us to assess lead times in a population-based series. Method. Patients diagnosed with retroperitoneal...... sarcoma in the southern Sweden health care region 2003-2009 were eligible for the study. Data on referrals and diagnostic investigations were collected from clinical files from primary health care, local hospitals, and from the sarcoma centre. Lead times were divided into patient delays and health care...... at the general practitioner, 36 days at local hospitals, and 55 days at the sarcoma centre. Conclusion. Centralization per se is not sufficient for optimized and efficient management. Our findings suggest that delays can be minimized by direct referral of patients from primary health care to sarcoma centers...

  16. On stochastic differential equations with random delay

    International Nuclear Information System (INIS)

    Krapivsky, P L; Luck, J M; Mallick, K

    2011-01-01

    We consider stochastic dynamical systems defined by differential equations with a uniform random time delay. The latter equations are shown to be equivalent to deterministic higher-order differential equations: for an nth-order equation with random delay, the corresponding deterministic equation has order n + 1. We analyze various examples of dynamical systems of this kind, and find a number of unusual behaviors. For instance, for the harmonic oscillator with random delay, the energy grows as exp((3/2) t 2/3 ) in reduced units. We then investigate the effect of introducing a discrete time step ε. At variance with the continuous situation, the discrete random recursion relations thus obtained have intrinsic fluctuations. The crossover between the fluctuating discrete problem and the deterministic continuous one as ε goes to zero is studied in detail on the example of a first-order linear differential equation

  17. Delay time and tunneling transient phenomena

    International Nuclear Information System (INIS)

    Garcia-Calderon, Gaston; Villavicencio, Jorge

    2002-01-01

    Analytic solutions to the time-dependent Schroedinger equation for cutoff wave initial conditions are used to investigate the time evolution of the transmitted probability density for tunneling. For a broad range of values of the potential barrier opacity α, we find that the probability density exhibits two evolving structures. One refers to the propagation of a forerunner related to a time domain resonance [Phys. Rev. A 64, 0121907 (2001)], while the other consists of a semiclassical propagating wave front. We find a regime where the forerunners are absent, corresponding to positive time delays, and show that this regime is characterized by opacities α c . The critical opacity α c is derived from the analytical expression for the delay time, which reflects a link between transient effects in tunneling and the delay time

  18. Delayed switching applied to memristor neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Frank Z.; Yang Xiao; Lim Guan [Future Computing Group, School of Computing, University of Kent, Canterbury (United Kingdom); Helian Na [School of Computer Science, University of Hertfordshire, Hatfield (United Kingdom); Wu Sining [Xyratex, Havant (United Kingdom); Guo Yike [Department of Computing, Imperial College, London (United Kingdom); Rashid, Md Mamunur [CERN, Geneva (Switzerland)

    2012-04-01

    Magnetic flux and electric charge are linked in a memristor. We reported recently that a memristor has a peculiar effect in which the switching takes place with a time delay because a memristor possesses a certain inertia. This effect was named the ''delayed switching effect.'' In this work, we elaborate on the importance of delayed switching in a brain-like computer using memristor neural networks. The effect is used to control the switching of a memristor synapse between two neurons that fire together (the Hebbian rule). A theoretical formula is found, and the design is verified by a simulation. We have also built an experimental setup consisting of electronic memristive synapses and electronic neurons.

  19. Delayed switching applied to memristor neural networks

    International Nuclear Information System (INIS)

    Wang, Frank Z.; Yang Xiao; Lim Guan; Helian Na; Wu Sining; Guo Yike; Rashid, Md Mamunur

    2012-01-01

    Magnetic flux and electric charge are linked in a memristor. We reported recently that a memristor has a peculiar effect in which the switching takes place with a time delay because a memristor possesses a certain inertia. This effect was named the ''delayed switching effect.'' In this work, we elaborate on the importance of delayed switching in a brain-like computer using memristor neural networks. The effect is used to control the switching of a memristor synapse between two neurons that fire together (the Hebbian rule). A theoretical formula is found, and the design is verified by a simulation. We have also built an experimental setup consisting of electronic memristive synapses and electronic neurons.

  20. Delayed feedback control in quantum transport.

    Science.gov (United States)

    Emary, Clive

    2013-09-28

    Feedback control in quantum transport has been predicted to give rise to several interesting effects, among them quantum state stabilization and the realization of a mesoscopic Maxwell's daemon. These results were derived under the assumption that control operations on the system are affected instantaneously after the measurement of electronic jumps through it. In this contribution, I describe how to include a delay between detection and control operation in the master equation theory of feedback-controlled quantum transport. I investigate the consequences of delay for the state stabilization and Maxwell's daemon schemes. Furthermore, I describe how delay can be used as a tool to probe coherent oscillations of electrons within a transport system and how this formalism can be used to model finite detector bandwidth.