| 1. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 4. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 6. |
- Ebrahimi-Fakhari, Darius, et al.
(författare)
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Defining the clinical, molecular and imaging spectrum of adaptor protein complex 4-associated hereditary spastic paraplegia
- 2020
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Ingår i: Brain. - OXFORD ENGLAND : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 143:10, s. 2929-2944
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Tidskriftsartikel (refereegranskat)abstract
- Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to prototypical yet poorly understood forms of childhood-onset and complex hereditary spastic paraplegia: SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). Here, we report a detailed cross-sectional analysis of clinical, imaging and molecular data of 156 patients from 101 families. Enrolled patients were of diverse ethnic backgrounds and covered a wide age range (1.0-49.3 years). While the mean age at symptom onset was 0.8 +/- 0.6 years [standard deviation (SD), range 0.2-5.0], the mean age at diagnosis was 10.2 +/- 8.5 years (SD, range 0.1-46.3). We define a set of core features: early-onset developmental delay with delayed motor milestones and significant speech delay (50% non-verbal); intellectual disability in the moderate to severe range; mild hypotonia in infancy followed by spastic diplegia (mean age: 8.4 +/- 5.1 years, SD) and later tetraplegia (mean age: 16.1 +/- 9.8 years, SD); postnatal microcephaly (83%); foot deformities (69%); and epilepsy (66%) that is intractable in a subset. At last follow-up, 36% ambulated with assistance (mean age: 8.9 +/- 6.4 years, SD) and 54% were wheelchair-dependent (mean age: 13.4 +/- 9.8 years, SD). Episodes of stereotypic laughing, possibly consistent with a pseudobulbar affect, were found in 56% of patients. Key features on neuroimaging include a thin corpus callosum (90%), ventriculomegaly (65%) often with colpocephaly, and periventricular white-matter signal abnormalities (68%). Iron deposition and polymicrogyria were found in a subset of patients. AP4B1-associated SPG47 and AP4M1-associated SPG50 accounted for the majority of cases. About two-thirds of patients were born to consanguineous parents, and 82% carried homozygous variants. Over 70 unique variants were present, the majority of which are frameshift or nonsense mutations. To track disease progression across the age spectrum, we defined the relationship between disease severity as measured by several rating scales and disease duration. We found that the presence of epilepsy, which manifested before the age of 3 years in the majority of patients, was associated with worse motor outcomes. Exploring genotype-phenotype correlations, we found that disease severity and major phenotypes were equally distributed among the four subtypes, establishing that SPG47, SPG50, SPG51 and SPG52 share a common phenotype, an 'AP-4 deficiency syndrome'. By delineating the core clinical, imaging, and molecular features of AP-4-associated hereditary spastic paraplegia across the age spectrum our results will facilitate early diagnosis, enable counselling and anticipatory guidance of affected families and help define endpoints for future interventional trials.
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| 8. |
- Aydin, C., et al.
(författare)
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Synthesis, diffused reflectance and electrical properties of nanocrystalline Fe-doped ZnO via sol-gel calcination technique
- 2013
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Ingår i: Optics and Laser Technology. - : Elsevier BV. - 0030-3992. ; 48, s. 447-452
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Tidskriftsartikel (refereegranskat)abstract
- The nanocrystalline ZnO:Fe semiconductor oxides were successfully synthesized via the sol-gel calcination method. Structural, optical and electrical properties of the investigated samples were characterized by various techniques such as atomic force microscopy (AFM), UV-vis absorption and electrical transport measurements. The optical band gap for undoped ZnO (3.19 eV) decreases (2.75 eV) with increasing Fe-doped ZnO (20%). The temperature dependences of the electrical conductivities of undoped ZnO and Fe-doped ZnO were measured and analyzed by Arrhenius equation. The electrical conductivity of the samples decreases with the increase of Fe doping ratio; hence, the electrical conductivity mechanism is controlled by thermally activated processes. To support the nanostructure of Fe-doped ZnO, AFM micrographs were performed. (C) 2012 Elsevier Ltd. All rights reserved.
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| 14. |
- Mahmmoud Sayed, Abd El-sadek, et al.
(författare)
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CdTe@Cu(OH)(2) nanocomposite: Aqueous synthesis and characterization
- 2011
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Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596. ; 184:5, s. 1135-1140
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Tidskriftsartikel (refereegranskat)abstract
- CdTe@Cu(OH)(2) nanocomposites were synthesized in aqueous solution by a seed-mediated growth approach. The effect of refluxing time and the concentration of Cu2+ on the preparation of these samples were measured using UV-visible absorption and photoluminescence analysis. The emission peak of the synthesized nanocomposites (CdTe@Cu(OH)(2)) was shifted from 605 (CdTe seed) to 621 nm. The size of CdTe nanoparticles were averaged about 3.22 nm, and the CdTe@Cu(OH)(2) nanocomposites were averaged as 5.19 nm. The synthesized CdTe@Cu(OH)(2) nanocomposite were characterized with XRD, EDAX, TEM, FT-IR, EPR, and thermal analysis (TG/DTG curves). The results indicate that as-prepared nanoparticles with core/shell structure exhibit interesting optical properties. (C) 2011 Elsevier Inc. All rights reserved.
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| 15. |
- Mahmmoud Sayed, Abd El-sadek, et al.
(författare)
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Electronic transport mechanism of CdTe nanocrystalline
- 2011
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Ingår i: Materials Chemistry and Physics. - : Elsevier BV. - 0254-0584. ; 130:1-2, s. 591-597
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Tidskriftsartikel (refereegranskat)abstract
- CdTe nanocrystalline powder was synthesized by chemical process. The structure of CdTe nanocrystalline was investigated by means of X-ray diffraction (XRD) technique, energy-dispersive X-ray analysis (EDAX) spectrum and transmission electron microscopy (TEM). The selected area electron diffraction (SAED) study confirms the crystallinity of the CdTe nanocrystalline. Some structural parameters such as the mean crystallite size, the dislocation density and the strain were calculated. The temperature dependence of the dc and ac conductivity was measured in the temperature range 293-423 K. It was found that the dc conductivity is thermally activated type. Values of dc activation energy and the pre-exponential were determined. The ac conductivity was found to increase with increasing both the temperature and frequency and follows the power low. The frequency exponent s was found to decrease with increasing temperature. The correlated barrier hopping (CBH) model was found to be applying to the ac conductivity data. The maximum barrier height W(m) and the density of localized states N(E(F)) were calculated and equal to 0.47 eV and 8.82 x 10(22) to 1.43 x10(23) eV(-1) cm(-3), respectively. CdTe nanomaterial is a good candidate for semiconductor devices due to its high conductivity. (C) 2011 Elsevier B.V. All rights reserved.
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| 16. |
- Mahmmoud Sayed, Abd El-sadek, et al.
(författare)
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Influence of different stabilizers on the optical and nonlinear optical properties of CdTe nanoparticles
- 2011
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Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018. ; 284:12, s. 2900-2904
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Tidskriftsartikel (refereegranskat)abstract
- CdTe semiconductor nanocrystals were synthesized with three different stabilizers: Mercaptoacetic Acid (MM), Mercaptopropionic Acid (MPA) and 2-Mercaptoethanol (ME) at pH approximate to 11.2 by wet chemical route using potassium tellurite and cadmium chloride as starting materials. The effect of capping agent on the preparation of these samples was evaluated using UV-Visible absorption and photoluminescence analysis. With the same reaction time but with different stabilizers, nanocrystals of different diameters were obtained. The average full width at half maximum of the photoluminescence spectra was about 69 nm which indicates that the monodispersity was quite good. The particle size was calculated by Debye-Scherrer equation from XRD data. Further characterization studies such as FT-IR and optical nonlinearity studies on the samples were carried out and the results are discussed. (C) 2011 Elsevier B.V. All rights reserved.
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| 17. |
- Muser, Daniele, et al.
(författare)
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Prognostic Value of Nonischemic Ringlike Left Ventricular Scar in Patients With Apparently Idiopathic Nonsustained Ventricular Arrhythmias
- 2021
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Ingår i: Circulation. - : LIPPINCOTT WILLIAMS & WILKINS. - 0009-7322 .- 1524-4539. ; 143:14, s. 1359-1373
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Tidskriftsartikel (refereegranskat)abstract
- Background: Left ventricular (LV) scar on late gadolinium enhancement (LGE) cardiac magnetic resonance has been correlated with life-threatening arrhythmic events in patients with apparently idiopathic ventricular arrhythmias (VAs). We investigated the prognostic significance of a specific LV-LGE phenotype characterized by a ringlike pattern of fibrosis. Methods: A total of 686 patients with apparently idiopathic nonsustained VA underwent contrast-enhanced cardiac magnetic resonance. A ringlike pattern of LV scar was defined as LV subepicardial/midmyocardial LGE involving at least 3 contiguous segments in the same short-axis slice. The end point of the study was time to the composite outcome of all-cause death, resuscitated cardiac arrest because of ventricular fibrillation or hemodynamically unstable ventricular tachycardia and appropriate implantable cardioverter defibrillator therapy. Results: A total of 28 patients (4%) had a ringlike pattern of scar (group A), 78 (11%) had a non-ringlike pattern (group B), and 580 (85%) had normal cardiac magnetic resonance with no LGE (group C). Group A patients were younger compared with groups B and C (median age, 40 vs 52 vs 45 years; P<0.01), more frequently men (96% vs 82% vs 55%; P<0.01), with a higher prevalence of family history of sudden cardiac death or cardiomyopathy (39% vs 14% vs 6%; P<0.01) and more frequent history of unexplained syncope (18% vs 9% vs 3%; P<0.01). All patients in group A showed VA with a right bundle-branch block morphology versus 69% in group B and 21% in group C (P<0.01). Multifocal VAs were observed in 46% of group A patients compared with 26% of group B and 4% of group C (P<0.01). After a median follow-up of 61 months (range, 34-84 months), the composite outcome occurred in 14 patients (50.0%) in group A versus 15 (19.0%) in group B and 2 (0.3%) in group C (P<0.01). After multivariable adjustment, the presence of LGE with ringlike pattern remained independently associated with increased risk of the composite end point (hazard ratio, 68.98 [95% CI, 14.67-324.39], P<0.01). Conclusions: In patients with apparently idiopathic nonsustained VA, nonischemic LV scar with a ringlike pattern is associated with malignant arrhythmic events.
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| 18. |
- Muser, Daniele, et al.
(författare)
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Risk Stratification of Patients With Apparently Idiopathic Premature Ventricular Contractions A Multicenter International CMR Registry
- 2020
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Ingår i: JACC. - : ELSEVIER. - 2405-500X .- 2405-5018. ; 6:6, s. 722-735
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES This study investigated the prevalence and prognostic significance of concealed myocardial abnormalities identified by cardiac magnetic resonance (CMR) imaging in patients with apparently idiopathic premature ventricular contractions (PVCs). BACKGROUND The rote of CMR imaging in patients with frequent PVCs and otherwise negative diagnostic workup is uncertain. METHODS This was a multicenter, international study that included 518 patients (age 44 +/- 15 years; 57% men) with frequent (>1,000/24 h) PVCs and negative routine diagnostic workup. Patients underwent a comprehensive CMR protocol including late gadolinium enhancement imaging for detection of necrosis and/or fibrosis. The study endpoint was a composite of sudden cardiac death, resuscitated cardiac arrest, and nonfatal episodes of ventricular fibrillation or sustained ventricular tachycardia that required appropriate implantable cardioverter-defibrillator therapy. RESULTS Myocardial abnormalities were found in 85 (16%) patients. Mate gender (odds ratio [OR]: 4.28; 95% confidence interval [CI]: 2.06 to 8.93; p = 0.01), family history of sudden cardiac death and/or cardiomyopathy (OR: 3.61; 95% CI: 1.33 to 9.82; p = 0.01), multifocat PVCs (OR: 11.12; 95% CI: 4.35 to 28.46; p < 0.01), and non-left bundle branch block inferior axis morphology (OR: 14.11; 95% CI: 7.35 to 27.07; p < 0.01) were alt significantly related to the presence of myocardial abnormalities. After a median follow-up of 67 months, the composite endpoint occurred in 26 (5%) patients. Subjects with myocardial abnormalities on CMR had a higher incidence of the composite outcome (n = 25; 29%) compared with those without abnormalities (n = 1; 0.2%; p < 0.01). CONCLUSIONS CMR can identify concealed myocardial abnormalities in 16% of patients with apparently idiopathic frequent PVCs. Presence of myocardial abnormalities on CMR predict worse clinical outcomes. (C) 2019 by the American College of Cardiology Foundation.
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| 20. |
- Sadek, Medhat M., et al.
(författare)
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Glomerular representation of plant volatiles and sex pheromone components in the antennal lobe of the female Spodoptera littoralis.
- 2002
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Ingår i: Journal of Experimental Biology. - 1477-9145. ; 205:10, s. 1363-1376
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Tidskriftsartikel (refereegranskat)abstract
- We studied the projection patterns of antennal lobe (AL) interneurones sensitive to plant volatiles and female-produced sex pheromone components in the female moth, Spodoptera littoralis. Ten compounds (eight plant-derived compounds and two sex pheromone components) were singly applied to the antenna and, using intracellular recording and staining techniques, the physiological and morphological characteristics of responding neurones were investigated. In addition, ALs stained with a synapsin antibody were optically sectioned using confocal microscopy, and a three-dimensional map of glomeruli in the anterior aspect of the AL was reconstructed. We used the map as a reference for identification of glomeruli innervated by projection neurones (PNs) that respond to plant volatiles and/or pheromone components. Nineteen PNs, responding to one to seven compounds of the ten tested stimuli, were stained with neurobiotin. These neurones each arborised in a single glomerulus in the frontal side of the AL. PNs responding to the same compound arborised in different glomeruli and PNs arborising in the same glomerulus responded to different compounds. Accordingly, glomeruli harbouring the dendritic arborisations of PNs responding to each of the tested compounds constituted a unique array of glomeruli that were not necessarily adjacent. It was thus clear that, at the output level, a single plant volatile or a sex pheromone component was not represented within a single glomerulus in the AL. We expect complex patterns of glomeruli to be involved in the coding of plant-derived compounds, as well as sex pheromone components, in female S. littoralis.
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| 21. |
- Yahia, I. S., et al.
(författare)
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Methyl orange (CI acid orange 52) as a new organic semiconductor: Conduction mechanism and dielectrical relaxation
- 2012
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Ingår i: Dyes and Pigments. - : Elsevier BV. - 1873-3743 .- 0143-7208. ; 93:1-3, s. 1434-1440
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Tidskriftsartikel (refereegranskat)abstract
- The structural, electrical and dielectrical properties of the methyl orange (MO) have been investigated by X-ray diffraction and thermal analysis methods. The electrical conduction and dielectrical relaxation mechanisms of the organic compound at various frequencies and temperatures were analyzed by impedance spectroscopy. The direct current (DC) electrical conductivity confirmed that methyl orange is an organic semiconductor with calculated electronic parameters. The alternating current (AC) electrical conductivity of the sample is controlled by the correlated barrier hopping (CBH) conduction mechanism. The values of the activation energy, the density of states and the binding energy for the alternating current mechanism were determined. The real and imaginary (Z' and Z '') parts of the impedance were found to be a frequency dependence. It was found that Cole-Cole plots of the sample confirm the existence of a temperature-dependent non-Debye relaxation mechanism. (C) 2011 Elsevier Ltd. All rights reserved.
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| 22. |
- Zheng, Kaibo, et al.
(författare)
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Effect of metal oxide morphology on electron injection from CdSe quantum dots to ZnO
- 2013
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 102:16
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Tidskriftsartikel (refereegranskat)abstract
- Performance of quantum dot sensitized solar cells relies on a rapid electron injection from quantum dot to metal oxide. We studied the injection process in CdSe-ZnO system by ultrafast time-resolved absorption spectroscopy for two types of acceptor morphologies-nanowires and nanoparticles' films. Based on comparison between experimental data and Marcus theory, we demonstrate that the acceptor morphology has a significant impact on electron injection due to (i) change in material permittivity and (ii) different density of the band-edge states. The results open a reference to improve injection efficiency in quantum dot-metal oxide system by selection of the acceptor morphology. (C) 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4803173]
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