801 research outputs found
Visceral artery aneurysms: a single centre experience
No full textAbstract
BACKGROUND:
Splanchnic artery areurysm is a rare but clinically relevant disease, showing a high mortality rate in emergency surgery. Reports on splanchnic aneurysms are rare and often anecdotal. The aim of this study is to discuss data obtained from 16 patients in a single vascular surgery center.
MATERIALS AND METHODS:
Between January 1987 and December 2000, 16 patients underwent surgery for splanchnic artery aneurysms. In 13 patients the localization was single (in two associated with an infrarenal abdominal aortic aneurysm) and in 3 patients multiple. The arteries involved were: splenic (8), hepatic (4), celiac (3), superior mesenteric (3), ileocolic (2), and pancreatoduodenal (1). 13 patients were asymptomatic and 3 presentec with abdominal pain. All patients underwent CT scan, and abdominal aortic and selective visceral artery angiography. Before surgery, all patients underwent cerebral MR or cerebral CT scan. 13 patients underwent open vascular surgery; 3 patients (2 splenic and 1 hepatic) underwent endovascular procedure (angioembolization). Histological examination of the aneurysmal wall was obtained in 14 patients. Ultrasound examination was performed after 6 months, then yearly. 14 patients underwent abdominal CT scan during the long-term follow-up.
RESULTS:
Perioperative mortality was absent. 12 cases were classified as displastic, with minor or major secondary atherosclerotic changes, and in many cases severe calcications. 2 cases were classified as atherosclerotic. Cerebral MR did not show any cases of intracerebral displastric aneurismal disease. One patient was lost at follow-up after 9 years. One patient showed a recurrence at 6 years (superior mesenteric artery): the patient underwent a new surgical procedure and died 20 days after surgery for intestinal infarction. All abdominal follow-up CT scans show good results of the vascular reconstruction and escluded other new visceral or aortic aneurysms.
CONCLUSIONS:
Visceral artery aneurysms are an uncommon form of abdominal vascular disease showing a high postoperative mortality rate in emergencies. Surgery, and in selected cases, endovascular treatment, can successfully manage splanchnic artery aneurysms with few complications and low recurrence
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
Singular equivalence and the (Fg) condition
No full textAbstractWe show that singular equivalences of Morita type with level between finite-dimensional Gorenstein algebras over a field preserve the (Fg) condition
De functie van kraton FG als compatibilizer in blends van nylon-6 en polypropyleen
No full textHet afstudeerproject maakte deel uit van een bij KSLA lopend onderzoek naar de werking van blok-copolymeren als compatibilizer, met name de door SHELL vervaardigde SBS en SEBS blok-copolymeren. Het voorgestelde systeem om de experimenten in het kader van de afstudeeropdracht mee uit te voeren is nylon-6/polypropyleen met kraton FG als compatibilizer. Kraton FG is een met maleinezuuranhydride gefunctionaliseerd SEBS blok-copolymeer. Kraton FG is een goede compatibilizer voor blends van nylon-6 en polypropyleen. De grensvlakspanning werd verlaagd, waardoor een fijnere dispersie verkregen werd. De slagvastheid nam toe. Het is niet goed mogelijk om een verband te leggen tussen de verlaging van de grensvlakspanning en de verlaging van de deeltjesgrootte. In dit onderzoek werd de grensvlakspanning in een 'spinning drop' met behulp van enkele methoden bepaald. Bij SHELL is een methode ontwikkeld, die aanzienlijk lagere grensvlakspanningen leverde dan de andere methoden. De tijdsduur van een meting volgens deze methode is ook veel lager (1- 2 uur in plaats van 4-6 uur). De toename van de slagvastheid was het grootst in blends met 25% disperse fase (6.25% kraton FG). Dit was het maximum in de serie blends, die tijdens dit onderzoek getest werden. Om de verbetering van de slagvastheid ten gevolge van de aanwezigheid van kraton FG te begrijpen, moet ook naar de eigenschappen van de matrix fase gekeken worden. De hechting tussen beide fasen zal door de aanwezigheid van kraton FG niet verbeterd worden. Dit is ook niet nodig, daar 'shear yielding' het voornaamste 'toughening' mechanisme in nylon-6 is. Door de reactie tussen kraton FG en nylon-6 zal de viscositeit van de matrix-fase toenemen. Deze verhoging van de viscositeit zal van invloed zijn op het dispersieproces. Dit verschijnsel is nog niet goed bekend, daar het onderzoek naar compatibilizers vooral gericht is op het grensvlak tussen de matrix en disperse fase (grensvlakspanning, adhesie). Door de aanwezigheid van compatibilizers wordt coalescentie van de deeltjes tegengegaan. De verklaring, die hiervoor gegeven wordt, is kinetisch van aard. Het is goed mogelijk dat coalescentie van twee deeltjes thermodynamisch ongunstig is ten gevolge van de aanwezigheid van compatibilizers aan het grensvlak.Applied Science
A designer FG-Nup that reconstitutes the selective transport barrier of the nuclear pore complex
No full textNuclear Pore Complexes (NPCs) regulate bidirectional transport between the nucleus and the cytoplasm. Intrinsically disordered FG-Nups line the NPC lumen and form a selective barrier, where transport of most proteins is inhibited whereas specific transporter proteins freely pass. The mechanism underlying selective transport through the NPC is still debated. Here, we reconstitute the selective behaviour of the NPC bottom-up by introducing a rationally designed artificial FG-Nup that mimics natural Nups. Using QCM-D, we measure selective binding of the artificial FG-Nup brushes to the transport receptor Kap95 over cytosolic proteins such as BSA. Solid-state nanopores with the artificial FG-Nups lining their inner walls support fast translocation of Kap95 while blocking BSA, thus demonstrating selectivity. Coarse-grained molecular dynamics simulations highlight the formation of a selective meshwork with densities comparable to native NPCs. Our findings show that simple design rules can recapitulate the selective behaviour of native FG-Nups and demonstrate that no specific spacer sequence nor a spatial segregation of different FG-motif types are needed to create selective NPCs.</p
Analytical and FE Modeling of FG Beams Based on A Refined Shear Deformable Beam Theory for Static and Dynamic Analyses of FG BeamsWith Thermoelastic Coupling
No full textThe static and dynamic thermoelastic analyses of the beams made of functionally graded materials (FGMs) are presented in this paper. Based on the refined third-order shear deformation beam theory proposed by the senior author and the variational principle, the governing equations of FG beams are deduced. The influence of temperature on Young’s modulus and coefficients of thermal expansion is taken into account when FG beams are subjected to thermal loading. The resulting governing equations are a system of the eighth-order differential equations in terms of displacement variables, and the thermoelastic coupling is included in the equations. An accurate and reliable two-noded beam element is developed for the bending and free vibration analysis of FG beams by employing the refined thirdorder shear deformation beam theory and the quasi-conforming element technique. Several typical examples of FG beams are solved using the present FG beam element to show the effects of the material distribution and thermal loading on the defections, stresses and natural frequencies of FG beams. The accuracy of both the analytical solutions and numerical results given by the proposed models are validated against the results reported in the literature or the 2D finite element results solved by the authors. The results show that the present models are capable of yielding not only accurate displacements but also accurate stresses and higher-order frequencies of free vibration for the FG beams with thermoelastic coupling
Author response image 1. Author response
No full textNuclear pore complexes (NPCs) conduct massive transport mediated by shuttling nuclear transport receptors (NTRs), while keeping nuclear and cytoplasmic contents separated. The NPC barrier in Xenopus relies primarily on the intrinsically disordered FG domain of Nup98. We now observed that Nup98 FG domains of mammals, lancelets, insects, nematodes, fungi, plants, amoebas, ciliates, and excavates spontaneously and rapidly phase-separate from dilute (submicromolar) aqueous solutions into characteristic 'FG particles'. This required neither sophisticated experimental conditions nor auxiliary eukaryotic factors. Instead, it occurred already during FG domain expression in bacteria. All Nup98 FG phases rejected inert macromolecules and yet allowed far larger NTR cargo complexes to rapidly enter. They even recapitulated the observations that large cargo-domains counteract NPC passage of NTR.cargo complexes, while cargo shielding and increased NTR.cargo surface-ratios override this inhibition. Their exquisite NPC-typical sorting selectivity and strong intrinsic assembly propensity suggest that Nup98 FG phases can form in authentic NPCs and indeed account for the permeability properties of the pore
Resposta de variedades aprimoradas de feno-grego (Trigonella foenum-graecum L.) ao oídio (erysiphe polygoni) e sua avaliação de desempenho em condições de campo naturais na zona de Wolaita, no Sul da Etiópia
No full textPowdery mildew is one of the most important diseases that constrain fenugreek production and productivity in fenugreek-growing areas of Ethiopia where mid to high land environmental conditions prevail. Thus, this study was conducted to evaluate the performance and response of six fenugreek varieties to powdery mildew under field conditions in the Wolaita Zone, Southern Ethiopia, in the 2020/2021 cropping seasons. The treatments consisted of six released fenugreek varieties that were laid out in an RCBD with three replications. Disease severity was assessed as the proportion of leaf area affected by the disease on 10 randomly selected plants in the middle two rows. The AUDPC was estimated from the percent severity index. The results revealed that the terminal disease severity varied from 27.00 to 48.67PSI at Sodo Zuria; and 23.67 to 57.33PSI at Damot Gale, respectively. AUDPC varied from 530.80 to 907.07%-days in Sodo Zuria and from 341.80 to 668.50%-days in Damot Gale. The varieties Bishoftu, FG-10, and Challa exhibited high disease severity and high AUDPC and were categorized as susceptible fenugreek varieties. It is concluded that under field conditions, different fenugreek varieties responded differently to powdery mildew, and the disease severity was strongly affected by the use of different resistance levels of fenugreek varieties and differences in the environmental conditions. It is, therefore, promising to use the two varieties, such as Ebbisa and Hunda, which were considered resistant under field conditions and that are recommended to be used by farmers in the study areas and elsewhere with similar agroecologies in Ethiopia.O oídio é uma das doenças mais importantes que limitam a produção e produtividade do feno-grego nas áreas de cultivo desse vegetal na Etiópia, onde prevalecem condições ambientais em regiões de média a alta altitude. Assim, este estudo foi conduzido para avaliar o desempenho e a resposta de seis variedades de feno-grego ao oídio em condições de campo na Zona de Wolaita, Sul da Etiópia, durante as safras de 2020/2021. Os tratamentos consistiram em seis variedades de feno-grego lançadas, dispostas em um delineamento de blocos casualizados com três repetições cada. A gravidade da doença foi avaliada como a proporção da área foliar afetada pela doença em dez plantas selecionadas aleatoriamente nas duas fileiras do meio. O AUDPC foi estimado a partir do índice percentual de gravidade. Os resultados revelaram que a gravidade final da doença variou de 27,00 a 48,67 PSI em Sodo Zuria e de 23,67 a 57,33 PSI em Damot Gale, respectivamente. A progressão da doença, medida pela Área Abaixo da Curva de Progresso da Doença, variou entre as localidades. Em Sodo Zuria, o AUDPC variou de 530,80 a 907,07%-dias, enquanto em Damot Gale, a variação foi de 341,80 a 668,50%-dias. As variedades Bishoftu, FG-10 e Challa apresentaram alta gravidade da doença e alto AUDPC, sendo categorizadas como variedades suscetíveis de feno-grego. Conclui-se que, em condições de campo, diferentes variedades de feno-grego responderam de maneira diferente ao oídio, e a gravidade da doença foi fortemente afetada pelo uso de diferentes níveis de resistência das variedades de feno-grego e diferenças nas condições ambientais. As variedades Ebbisa e Hunda demonstraram resistência promissora ao oídio em condições de campo, sendo altamente recomendadas para cultivo por agricultores nas áreas de estudo e em outras regiões da Etiópia com condições agroecológicas similares
Algebraic dynamic multilevel method for fractured geothermal reservoir simulation
No full textA dynamic multilevel method for fully-coupled simulation of flow and heat transfer in heterogeneous and fractured geothermal reservoirs is presented (FG-ADM). The FG-ADM develops an advanced simulation method which maintains its efficiency when scaled up to field-scale applications, at the same time, it remains accurate in presence of complex fluid physics and heterogeneous rock properties. The embedded discrete fracture model is employed to accurately represent fractures without the necessity of unstructured complex grids. On the fine-scale system, FG-ADM introduces a multi-resolution nested dynamic grid, based on the dynamic time-dependent solution of the heat and mass transport equations. The fully-coupled implicit simulation strategy, in addition to the multilevel multiscale framework, makes FG-ADM to be stable and efficient in presence of strong flow-heat coupling terms. Furthermore, its finite-volume formulation preserves local conservation for both mass and heat fluxes. Multi-level local basis functions for pressure and temperature are introduced, in order to accurately represent the heterogeneous fractured rocks. These basis functions are constructed at the beginning of the simulation, and are reused during the entire dynamic time-dependent simulation. For several heterogeneous test cases with complex fracture networks we show that, by employing only a fraction of the fine-scale grid cells, FG-ADM can accurately represent the complex flow-heat solutions in the fractured subsurface formations.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Numerical AnalysisReservoir Engineerin
Metformin attenuates fluctuating glucose-induced endothelial dysfunction through enhancing GTPCH1-mediated eNOS recoupling and inhibiting NADPH oxidase
No full textAbstractAimsThe aim of this study was to investigate whether and how metformin ameliorated endothelial dysfunction induced by fluctuating glucose (FG) in human umbilical vein endothelial cells (HUVECs).MethodsHUVECs, which were exposed to FG to induce endothelial dysfunction, were incubated with nitric oxide synthase (NOS) inhibitor N-nitro-l-arginine-methyl ester (l-NAME), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin, metformin and/or adenosine monophosphate-activated protein kinase (AMPK) inhibitor compound C. The oxidative stress and endothelial NOS (eNOS) coupling were evaluated.ResultsFG induced endothelial dysfunction as indicated by increased reactive oxygen species (ROS) generation and decreased nitric oxide (NO) production. Although FG increased eNOS phosphorylation, uncoupled eNOS was evidenced by downregulated guanosine 5′-triphosphate cyclohydrolase 1 (GTPCH1) and tetrahydrobiopterin (BH4) levels. FG also upregulated the level of p47-phox, a subunit of NADPH oxidase. Similar to l-NAME and apocynin, metformin ameliorated the FG-induced endothelial dysfunction by decreasing ROS generation. Furthermore, metformin recoupled eNOS through upregulating GTPCH1 and BH4 levels, and attenuated the upregulation of p47-phox in FG-treated HUVECs. Addition of compound C abolished the above effects of metformin.ConclusionMetformin improves the FG-induced endothelial dysfunction in HUVECs. The protective effect of metformin may be mediated through activation of GTPCH1-mediated eNOS recoupling and inhibition of NADPH oxidase via an AMPK-dependent pathway
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