Diagnostic Dilemma of Cardiac Syncope in Pediatric Patients

Aims Syncope is defined as temporary loss of consciousness and postural tone resulting from an abrupt transient decrease in cerebral blood flow. The present work aimed at determining how diagnostic tests are used in the evaluation of pediatric syncope at a tertiary pediatric referral center and to report on the utility and the yield of these tests.Settings and Design Retrospective study conducted at a tertiary referral arrhythmolology serviceMethods and Material The clinical charts of 234 pediatric patients presenting with a primary complaint of syncope with an average age of 7.48 ± 3.82(3.5-16) years were reviewed by the investigators.Statistical analysis used Statistical Package of social science (SPSS) version 9,0 was used for analysis of data.Results The commonest trigger for syncope in the study population was early following exercise (n=65) and the commonest prodrome was palpitation, noted in 25 patients. A murmur was present in 19 of our patients (8.3%) while 10.7% (n=25) had abnormal ECGs. Of the 106 echocardiograms done, 14 (13.2%) were abnormal. Only two of them were missed by ECG. All patients were offered ambulatory 24 hour ECG. One patient with sick sinus syndrome was diagnosed only with Holter.Conclusions Clues to the presence of cardiac syncope may include acute onset of syncope, frequent episodes, low difference between blood pressure readings in supine and erect positions (after standing for 2 minutes) and most importantly an abnormal 12 lead ECG. Transthoracic echo and Holter monitoring have low yield in pediatric syncope

Diffuse Hard X-ray Sources Discovered with the ASCA Galactic Plane Survey

We found diffuse hard X-ray sources, G11.0+0.0, G25.5+0.0, and G26.6-0.1 in the ASCA Galactic plane survey data. The X-ray spectra are featureless with no emission line, and are fitted with both models of a thin thermal plasma in non-equilibrium ionization and a power-law function. The source distances are estimated to be 1-8 kpc, using the best-fit NH values on the assumption that the mean density in the line of sight is 1 H cm^-3. The source sizes and luminosities are then 4.5-27 pc and (0.8-23)x10^33 ergs/s. Although the source sizes are typical to supernova remnants (SNR) with young to intermediate ages, the X-ray luminosity, plasma temperature, and weak emission lines in the spectra are all unusual. This suggests that these objects are either shell-like SNRs dominated by X-ray synchrotron emission, like SN 1006, or, alternatively, plerionic SNRs. The total number of these classes of SNRs in our Galaxy is also estimated.Comment: 17 pages, 9 figures; to appear in Ap

Accretion Disk Spectra of the Ultra-luminous X-ray Sources in Nearby Spiral Galaxies and Galactic Superluminal Jet Sources

Ultra-luminous Compact X-ray Sources (ULXs) in nearby spiral galaxies and Galactic superluminal jet sources share the common spectral characteristic that they have unusually high disk temperatures which cannot be explained in the framework of the standard optically thick accretion disk in the Schwarzschild metric. On the other hand, the standard accretion disk around the Kerr black hole might explain the observed high disk temperature, as the inner radius of the Kerr disk gets smaller and the disk temperature can be consequently higher. However, we point out that the observable Kerr disk spectra becomes significantly harder than Schwarzschild disk spectra only when the disk is highly inclined. This is because the emission from the innermost part of the accretion disk is Doppler-boosted for an edge-on Kerr disk, while hardly seen for a face-on disk. The Galactic superluminal jet sources are known to be highly inclined systems, thus their energy spectra may be explained with the standard Kerr disk with known black hole masses. For ULXs, on the other hand, the standard Kerr disk model seems implausible, since it is highly unlikely that their accretion disks are preferentially inclined, and, if edge-on Kerr disk model is applied, the black hole mass becomes unreasonably large (> 300 M_solar). Instead, the slim disk (advection dominated optically thick disk) model is likely to explain the observed super-Eddington luminosities, hard energy spectra, and spectral variations of ULXs. We suggest that ULXs are accreting black holes with a few tens of solar mass, which is not unexpected from the standard stellar evolution scenario, and that their X-ray emission is from the slim disk shining at super-Eddington luminosities.Comment: ApJ, accepte

Graphene for spintronics: giant Rashba splitting due to hybridization with Au

Graphene in spintronics has so far primarily meant spin current leads of high performance because the intrinsic spin-orbit coupling of its pi-electrons is very weak. If a large spin-orbit coupling could be created by a proximity effect, the material could also form active elements of a spintronic device such as the Das-Datta spin field-effect transistor, however, metal interfaces often compromise the band dispersion of massless Dirac fermions. Our measurements show that Au intercalation at the graphene-Ni interface creates a giant spin-orbit splitting (~100 meV) in the graphene Dirac cone up to the Fermi energy. Photoelectron spectroscopy reveals hybridization with Au-5d states as the source for the giant spin-orbit splitting. An ab initio model of the system shows a Rashba-split dispersion with the analytically predicted gapless band topology around the Dirac point of graphene and indicates that a sharp graphene-Au interface at equilibrium distance will account for only ~10 meV spin-orbit splitting. The ab initio calculations suggest an enhancement due to Au atoms that get closer to the graphene and do not violate the sublattice symmetry.Comment: 16 pages (3 figures) + supplementary information 16 pages (14 figures

The Nature of Ultra-Luminous Compact X-Ray Sources in Nearby Spiral Galaxies

Studies were made of ASCA spectra of seven ultra-luminous compact X-ray sources (ULXs) in nearby spiral galaxies; M33 X-8 (Takano et al. 1994), M81 X-6 (Fabbiano 1988b; Kohmura et al. 1994; Uno 1997), IC 342 Source 1 (Okada et al. 1998), Dwingeloo 1 X-1 (Reynolds et al. 1997), NGC 1313 Source B (Fabbiano & Trinchieri 1987; Petre et al. 1994), and two sources in NGC 4565 (Mizuno et al. 1999). With the 0.5--10 keV luminosities in the range 10^{39-40} ergs/s, they are thought to represent a class of enigmatic X-ray sources often found in spiral galaxies. For some of them, the ASCA data are newly processed, or the published spectra are reanalyzed. For others, the published results are quoted. The ASCA spectra of all these seven sources have been described successfully with so called multi-color disk blackbody (MCD) emission arising from optically-thick standard accretion disks around black holes. Except the case of M33 X-8, the spectra do not exhibit hard tails. For the source luminosities not to exceed the Eddington limits, the black holes are inferred to have rather high masses, up to ~100 solar masses. However, the observed innermost disk temperatures of these objects, Tin = 1.1--1.8 keV, are too high to be compatible with the required high black-hole masses, as long as the standard accretion disks around Schwarzschild black holes are assumed. Similarly high disk temperatures are also observed from two Galactic transients with superluminal motions, GRO 1655-40 and GRS 1915+105. The issue of unusually high disk temperature may be explained by the black hole rotation, which makes the disk get closer to the black hole, and hence hotter.Comment: submitted to ApJ, December 199

Hestia to Demeter: Reducing Agrochemical Pollution to Empower Women Farmers

The 2020 Farm to Fork strategy by the European Commission aimed to reduce agrochemical pollutants and protect biodiversity but stirred controversy due to conflicts between intensive agriculture demands and environmental priorities. Strict limits on agrochemical residues required farmers to produce less. The de-intensification and agroecology prone policy impacted livelihoods, sparking political upheaval. Due to lack of pesticide alternatives and extension services, Lebanese exports have faced challenges complying with residue restrictions. Agricultural laborers and consumers are exposed to high levels of pesticide residue. Undocumented refugee women form a significant part of the agricultural workforce, and women led agricultural cooperatives have minimal access to funding, exacerbating gender inequity. The American University of Beirut (AUB) has played a pivotal role in agroecology research, rural development, and gender equity. Knowledge transfer promotes civic awareness and private sector partnerships. Local Natural enemies and parasites emerged as a residue-free alternative to agrochemicals. Biocontrol-based integrated pest management holds great potential for mitigating pesticides hazards to human and environmental health. Launching the “natural predators” initiative from women-run farms holds a great promise in dually resolving the problems of agrochemical pollution and gender equity in the agricultural sector. Empowering women in agriculture aims to transform their role from care work to farm management. This paper focuses on the technical aspects of developing “natural enemies” as pesticides alternative for Lebanese agriculture, aiming to overcome export challenges and revitalize the economy. "Farm to Fork meets Hestia to Demeter" underscores AUB's commitment to sustainability aligns climate action with gender equity. By supporting women entrepreneurs and addressing climate change's impact on public health, the initiative contributes to AUB's broader mission of advancing Lebanon and the region through Education for Sustainable Development

Gemeinwohlorientierte Bodennutzung in Kooperation. Ein Handlungsleitfaden für öffentlich-zivielgesellschaftliche Partnerschaften

Dieser Handlungsleitfaden möchte die gemeinwohlorientierte Vergabe von Räumen und Flächen an zivilgesellschaftliche Gruppen stärken. Er ist als Inspirationssammlung zu verstehen, die den Weg zu neuen Kooperationen zwischen öffentlichen und zivilgesellschaftlichen Akteuren erleichtern soll. Wissenswertesund inspirierende Beispiele bieten eine Starthilfe, um nicht nur einzelne stadträumliche Experimente zu wagen, sondern die gemeinwohlorientierte Flächen- und Raumvergabe an zivilgesellschaftliche Gruppen kommunal zu verankern. Denn öffentliche Liegenschaften sind nach vielen Jahren der Privatisierung eine rare Ressource, die umso mehr dem Gemeinwohl dienen sollte

Laparoscopic versus open appendectomy in children with complicated appendicitis

Introduction: Acute appendicitis represents one of the most common causes of urgent surgical interventions in pediatric age group. With the advances in minimal invasive surgery laparoscopic appendectomy (LA) has been introduced as a suitable line of treatment. We compare between laparoscopic and conventional open appendectomy in the treatment of complicated appendicitis in children.Patients and methods: During the period from October 2012 to March 2016, 390 children with acute complicated appendicitis diagnosed clinically and with laboratory and available imaging studies were operated. LA performed for 200 cases and open conventional appendectomy for 190 cases. Three ports technique was used in laparoscopic cases. The operating table is shifted in Trendelenburg position and towards the left side. The surgeon stands on the left side of the patient. The appendicular mesoappendix was secured using electro cautery. The base was secured by extracorporeal ties and the appendix was retrieval within the umbilical port. The wounds were closed. Open appendectomy was done through McBurny incision as the traditional approach.Results: A total of 390 children diagnosed with acute complicated appendicitis were operated. The mean age was 12.04 years in group A and 12.2 in group B. There were 260 were boys and 130 were girls. The mean operative time in the laparoscopic group was 56.4 min; while in the conventional group was 63.42 min.Conclusion: LA was a suitable, effective and safe procedure in complicated cases that did not involve the base. It was associated with lower complications rate withall the advances of minimal invasive surgery when compared to the conventional open appendectomy.Keywords: appendectomy, children, complicated, laparoscopi

Probiotics and ascorbic acid improved radiographic bone density and mitigated oxidative stress and multiple organ dysfunction induced by heat stress in rats

Heat stress is a substantial environmental challenge that adversely affect health and performance. This study aimed to investigate the effect of advanced short-term dietary supplementation of probiotics or vitamin C on serum biochemical parameters, antioxidant status, and radiographic bone density in heat-stressed rats. A 48 male albino rat were randomly allocated into six groups: Control, Heat stress, Probiotics, Probiotics+Heat stress, Vitamin C, Vitamin C+Heat stress group. Rats in supplementation groups received probiotics or ascorbic acid orally from week 1 to 8. Heat stress groups were subjected to elevated temperature (42 ±1 ˚C and relative humidity 65 ± 2%) 60 minutes daily for 4 weeks starting from week 5 to 8, while other groups were maintained under standard laboratory conditions. Heat stress resulted in increased serum ALT, AST, urea and creatinine (P<0.001), decreased calcium, increased phosphorus and osteocalcin (P<0.001), increased serum MDA, decreased TAC (P<0.001), decreased radiographic bone density (P<0.001) compared to other groups. Histopathological examination of liver, kidney and adrenal glands reflected the ongoing heat-stress damage. Administration of probiotics and ascorbic acid demonstrated substantial protection, suggesting their potential efficacy against heat stress. The obtained findings hold promise for the development of novel strategies to enhance heat stress resilience in animals