980 resultados para MGS3 stratigraphic segment
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PURPOSE To report the incidence of anterior capsule contraction syndrome (ACCS) and to present a novel minimally invasive bimanual technique for anterior segment revision surgery associated with ACCS with anterior flexion of the intraocular lens haptics. METHODS A consecutive cohort of 268 eyes of 161 patients undergoing phacoemulsification and implantation of the same type of hydrophilic acrylic aspheric intraocular lens cohort were analysed and a novel technique of minimally invasive bimanual technique for anterior segment revision surgery is described. RESULTS We identified four eyes (1.5%) of three patients with advanced ACCS. Successful restoration of a clear visual axis with minimal induction of astigmatism and rapid visual rehabilitation was achieved in all four cases. CONCLUSION This technique is a safe and minimally invasive alternative to laser or vitrector-cut capsulotomy to restore a clear visual axis. In cases of advanced ACCS, it offers the option for haptic reposition or amputation.
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Abstract. Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was tectonically formed most likely within the Pliocene and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60m water depth. According to our data, significant lake level fluctuations with prominent lowstands of ca. 60 and 35m below the present water level occurred during Marine Isotope Stage (MIS) 6 and MIS 5, respectively. The effect of these lowstands on biodiversity in most coastal parts of the lake is negligible, due to only small changes in lake surface area, coastline, and habitat. In contrast, biodiversity in shallower areas was more severely affected due to disconnection of today sublacustrine springs from the main water body. Multichannel seismic data from deeper parts of the lake clearly image several clinoform structures stacked on top of each other. These stacked clinoforms indicate significantly lower lake levels prior to MIS 6 and a stepwise rise of water level with intermittent stillstands since its existence as water-filled body, which might have caused enhanced expansion of endemic species within Lake Ohrid.
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Upper Jurassic (Kimmeridgian)±Upper Cretaceous (Cenomanian) inner platform carbonates in the Western Taurides are composed of metre-scale upward-shallowing cyclic deposits (parasequences) and important karstic surfaces capping some of the cycles. Peritidal cycles (shallow subtidal facies capped by tidal-¯at laminites or fenestrate limestones) are regressive- and transgressive-prone (upward-deepening followed by upward-shallowing facies trends). Subtidal cycles are of two types and indicate incomplete shallowing. Submerged subtidal cycles are composed of deeper subtidal facies overlain by shallow subtidal facies. Exposed subtidal cycles consist of deeper subtidal facies overlain by shallow subtidal facies that are capped by features indicative of prolonged subaerial exposure. Subtidal facies occur characteristically in the Jurassic, while peritidal cycles are typical for the Lower Cretaceous of the region. Within the foraminiferal and dasyclad algal biostratigraphic framework, four karst breccia levels are recognized as the boundaries of major second-order cycles, introduced for the ®rst time in this study. These levels correspond to the Kimmeridgian±Portlandian boundary, mid-Early Valanginian, mid-Early Aptian and mid-Cenomanian and represent important sea level falls which affected the distribution of foraminiferal fauna and dasyclad ¯ora of the Taurus carbonate platform. Within the Kimmeridgian±Cenomanian interval 26 third-order sequences (types 1 and 2) are recognized. These sequences are the records of eustatic sea level ¯uctuations rather than the records of local tectonic events because the boundaries of the sequences representing 1±4 Ma intervals are correlative with global sea level falls. Third-order sequences and metre-scale cyclic deposits are the major units used for long-distance, high-resolution sequence stratigraphic correlation in the Western Taurides. Metre-scale cyclic deposits (parasequences) in the Cretaceous show genetical stacking patterns within third-order sequences and correspond to fourth-order sequences representing 100±200 ka. These cycles are possibly the E2 signal (126 ka) of the orbital eccentricity cycles of the Milankovitch band. The slight deviation of values, calculated for parasequences, from the mean value of eccentricity cycles can be explained by the currently imprecise geochronology established in the Cretaceous and missed sea level oscillations when the platform lay above fluctuating sea level.
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Background: Ischemia monitoring cannot always be performed by 12-lead ECG. Hence, the individual performance of the ECG leads is crucial. No experimental data on the ECG's specificity for transient ischemia exist. Methods: In 45 patients a 19-lead ECG was registered during a 1-minute balloon occlusion of a coronary artery (left anterior descending artery [LAD], right coronary artery [RCA] or left circumflex artery [LCX]). ST-segment shifts and sensitivity/specificity of the leads were measured. Results: During LAD occlusion, V3 showed maximal ST-segment elevation (0.26 mV [IQR 0.16–0.33 mV], p = 0.001) and sensitivity/specificity (88% and 80%). During RCA occlusion, III showed maximal ST-elevation (0.2 mV [IQR 0.09–0.26 mV], p = 0.004), aVF had the best sensitivity/specificity (85% and 68%). During LCX occlusion, V6 showed maximal ST-segment elevation (0.04 mV [IQR 0.02–0.14 mV], p = 0.005), and sensitivity/specificity was (31%/92%) but could be improved (63%/72%) using an optimized cut-off for ischemia. Conclusion: V3, aVF and V6 show the best performance to detect transient ischemia.
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Aims: Arterial plaque rupture and thrombus characterise ST-elevation myocardial infarction (STEMI) and may aggravate delayed arterial healing following durable polymer drug-eluting stent (DP-DES) implantation. Biodegradable polymer (BP) may improve biocompatibility. We compared long-term outcomes in STEMI patients receiving BP-DES vs. durable polymer sirolimus-eluting stents (DP-SES). Methods and results: We pooled individual patient-level data from three randomised clinical trials (ISAR-TEST-3, ISAR-TEST-4 and LEADERS) comparing outcomes from BP-DES with DP-SES at four years. The primary endpoint (MACE) comprised cardiac death, MI, or target lesion revascularisation (TLR). Secondary endpoints were TLR, cardiac death or MI, and definite or probable stent thrombosis. Of 497 patients with STEMI, 291 received BP-DES and 206 DP-SES. At four years, MACE was significantly reduced following treatment with BP-DES (hazard ratio [HR] 0.59, 95% CI: 0.39-0.90; p=0.01) driven by reduced TLR (HR 0.54, 95% CI: 0.30-0.98; p=0.04). Trends towards reduction were seen for cardiac death or MI (HR 0.63, 95% CI: 0.37-1.05; p=0.07) and definite or probable stent thrombosis (3.6% vs. 7.1%; HR 0.49, 95% CI: 0.22-1.11; p=0.09). Conclusions: In STEMI, BP-DES demonstrated superior clinical outcomes to DP-SES at four years. Trends towards reduced cardiac death or myocardial infarction and reduced stent thrombosis require corroboration in specifically powered trials.
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We have recorded reflection profiles of firn through large areas of West Antarctica and part of the East Antarctic plateau using 400 MHz short-pulse radar. The locations show accumulation rates that vary from well above to well below the vertical radar resolution. Most reflection horizons have extensive lateral continuity, and are composed of distinctive wavelets with a consistent phase polarity sequence within their successive half-cycles. We modeled these waveforms, and conclude that they arise from thin, double layers of ice over hoar, which is consistent with the standard model of firn stratification. In addition, we conclude that ice/hoar layers are extensive throughout West Antarctica and also present (although more sparsely) beneath the Antarctic Plateau.
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We investigate causes of the stratigraphic variation revealed in a 177 km, 400 MHz short-pulse radar profile of firn from West Antarctica. The profile covers 56 m depth, and its direction was close to those of the ice flow and mean wind. The average, near-surface accumulation rates calculated from the time delays of one radar horizon consistently show minima on leeward slopes and maxima on windward slopes, confirming an earlier study based on stake observations. The stratigraphic variation includes up to 30 m depth variation in individual horizons over tens of km, fold limbs that become progressively steeper with depth, and fold-hinge loci that change direction or propagate down-ice with depth over distances far less than predicted by the ice speeds. We use an accumulation rate model to show how local rate anomalies and the effect of ice speed upon a periodic variation in accumulation rate cause these phenomena, and we reproduce two key features seen in the stratigraphic variations. We conclude that the model provides an explanation of changes in spatial stratigraphy and local measures of accumulation history given the constraints of surface topography, ice and wind velocities, and a general accumulation rate for an area.
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We track dated firn horizons within 400 MHz short-pulse radar profiles to find the continuous extent over which they can be used as historical benchmarks to study past accumulation rates in West Antarctica. The 30-40 cm pulse resolution compares with the accumulation rates of most areas. We tracked a particular set that varied from 30 to 90 m in depth over a distance of 600 km. The main limitations to continuity are fading at depth, pinching associated with accumulation rate differences within hills and valleys, and artificial fading caused by stacking along dips. The latter two may be overcome through multi-kilometer distances by matching the relative amplitude and spacing of several close horizons, along with their pulse forms and phases. Modeling of reflections from thin layers suggests that the - 37 to - 50 dB range of reflectivity and the pulse waveforms we observed are caused by the numerous thin ice layers observed in core stratigraphy. Constructive interference between reflections from these close, high-density layers can explain the maintenance of reflective strength throughout the depth of the firn despite the effects of compaction. The continuity suggests that these layers formed throughout West Antarctica and possibly into East Antarctica as well.
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Paleoenvironmental and paleoclimate reconstructions based on molecular proxies, such as those derived from leaf-wax biomarkers, in loess-paleosol sequences represent a promising line of investigation in Quaternary research. The main premise of such reconstructions is the synsedimentary deposition of biomarkers and dust, which has become a debated subject in recent years. This study uses two independent approaches to test the stratigraphic integrity of leaf-wax biomarkers: (i) long-chain n-alkanes and fatty acids are quantified in two sediment-depth profiles in glacial till on the Swiss Plateau, consisting of a Holocene topsoil and the underlying B and C horizons. Since glacial sediments are initially very poor in organic matter, significant amounts of leaf-wax biomarkers in the B and C horizons of those profiles would reflect postsedimentary root-derived or microbial contributions. (ii) Compound-specific radiocarbon measurements are conducted on n-alkanes and n-alkanoic (fatty) acids from several depth intervals in the loess section "Crvenka", Serbia, and the results are compared to independent estimates of sediment age. We find extremely low concentrations of plant-wax n-alkanes and fatty acids in the B and C horizons below the topsoils in the sediment profiles. Moreover, compound-specific radiocarbon analysis yields plant-wax 14C ages that agree well with published luminescence ages and stratigraphy of the Serbian loess deposit. Both approaches confirm that postsedimentary, root-derived or microbial contributions are negligible in the two investigated systems. The good agreement between the ages of odd and even homologues also indicates that reworking and incorporation of fossil leaf waxes is not particularly relevant either.
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PURPOSE To investigate whether the prophylactic use of bevacizumab reduces the rate of rubeosis after proton therapy for uveal melanoma and improves the possibility to treat ischemic, reapplicated retina with laser photocoagulation. DESIGN Comparative retrospective case series. METHODS Uveal melanoma patients with ischemic retinal detachment and treated with proton therapy were included in this institutional study. Twenty-four eyes received prophylactic intravitreal bevacizumab injections and were compared with a control group of 44 eyes without bevacizumab treatment. Bevacizumab injections were performed at the time of tantalum clip insertion and were repeated every 2 months during 6 months, and every 3 months thereafter. Ultra-widefield angiography allowed determination of the extent of retinal ischemia, which was treated with laser photocoagulation after retinal reapplication. Main outcome measures were the time to rubeosis, the time to retinal reattachment, and the time to laser photocoagulation of ischemic retina. RESULTS Baseline characteristics were balanced between the groups, except for thicker tumors and larger retinal detachments in the bevacizumab group, potentially to the disadvantage of the study group. Nevertheless, bevacizumab prophylaxis significantly reduced the rate of iris rubeosis from 36% to 4% (log-rank test P = .02) and tended to shorten the time to retinal reapplication until laser photocoagulation of the nonperfusion areas could be performed. CONCLUSIONS Prophylactic intravitreal bevacizumab in patients treated with proton therapy for uveal melanoma with ischemic retinal detachment prevented anterior segment neovascularization, until laser photocoagulation to the reapplied retina could be performed.
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Due to their outstanding resolution and well-constrained chronologies, Greenland ice-core records provide a master record of past climatic changes throughout the Last Interglacial–Glacial cycle in the North Atlantic region. As part of the INTIMATE (INTegration of Ice-core, MArine and TErrestrial records) project, protocols have been proposed to ensure consistent and robust correlation between different records of past climate. A key element of these protocols has been the formal definition and ordinal numbering of the sequence of Greenland Stadials (GS) and Greenland Interstadials (GI) within the most recent glacial period. The GS and GI periods are the Greenland expressions of the characteristic Dansgaard–Oeschger events that represent cold and warm phases of the North Atlantic region, respectively. We present here a more detailed and extended GS/GI template for the whole of the Last Glacial period. It is based on a synchronization of the NGRIP, GRIP, and GISP2 ice-core records that allows the parallel analysis of all three records on a common time scale. The boundaries of the GS and GI periods are defined based on a combination of stable-oxygen isotope ratios of the ice (δ18O, reflecting mainly local temperature) and calcium ion concentrations (reflecting mainly atmospheric dust loading) measured in the ice. The data not only resolve the well-known sequence of Dansgaard–Oeschger events that were first defined and numbered in the ice-core records more than two decades ago, but also better resolve a number of short-lived climatic oscillations, some defined here for the first time. Using this revised scheme, we propose a consistent approach for discriminating and naming all the significant abrupt climatic events of the Last Glacial period that are represented in the Greenland ice records. The final product constitutes an extended and better resolved Greenland stratotype sequence, against which other proxy records can be compared and correlated. It also provides a more secure basis for investigating the dynamics and fundamental causes of these climatic perturbations.
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We conducted a stratigraphic analysis of the South Polar Layered Deposits (SPLDs) in Promethei Lingula (PL, Mars) based on the identification of regional unconformities at visible and radar wavelengths. According to the terrestrial classification, this approach constrains the stratigraphy of the region and remedies the ambiguous interpretation of stratigraphy through marker layers, bypassing the problem related to the morphologic and radiometric appearance of the layers. Thus, the approach does not exclude diverse classifications, but complements them, whereas other discriminant elements are doubtful or difficult/impossible to be defined. Using this approach, we defined two stratigraphic units (or synthems: PL1 and PL2) in PL, which are morphologically different and divided by a regional unconformity (AuR1). This stratigraphic architecture implies that the geological history of PL has been conditioned by periodic changes in climate, which in turn are related to orbital variations of Mars.
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INTRODUCTION AND OBJECTIVES There is continued debate about the routine use of aspiration thrombectomy in patients with ST-segment elevation myocardial infarction. Our aim was to evaluate clinical and procedural outcomes of aspiration thrombectomy-assisted primary percutaneous coronary intervention compared with conventional primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction. METHODS We performed a meta-analysis of 26 randomized controlled trials with a total of 11 943 patients. Clinical outcomes were extracted up to maximum follow-up and random effect models were used to assess differences in outcomes. RESULTS We observed no difference in the risk of all-cause death (pooled risk ratio = 0.88; 95% confidence interval, 0.74-1.04; P = .124), reinfarction (pooled risk ratio = 0.85; 95% confidence interval, 0.67-1.08; P = .176), target vessel revascularization (pooled risk ratio = 0.86; 95% confidence interval, 0.73-1.00; P = .052), or definite stent thrombosis (pooled risk ratio = 0.76; 95% confidence interval, 0.49-1.16; P = .202) between the 2 groups at a mean weighted follow-up time of 10.4 months. There were significant reductions in failure to reach Thrombolysis In Myocardial Infarction 3 flow (pooled risk ratio = 0.70; 95% confidence interval, 0.60-0.81; P < .001) or myocardial blush grade 3 (pooled risk ratio = 0.76; 95% confidence interval, 0.65-0.89; P = .001), incomplete ST-segment resolution (pooled risk ratio = 0.72; 95% confidence interval, 0.62-0.84; P < .001), and evidence of distal embolization (pooled risk ratio = 0.61; 95% confidence interval, 0.46-0.81; P = .001) with aspiration thrombectomy but estimates were heterogeneous between trials. CONCLUSIONS Among unselected patients with ST-segment elevation myocardial infarction, aspiration thrombectomy-assisted primary percutaneous coronary intervention does not improve clinical outcomes, despite improved epicardial and myocardial parameters of reperfusion. Full English text available from:www.revespcardiol.org/en.
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BACKGROUND Previous analyses reported age- and gender-related differences in the provision of cardiac care. The objective of the study was to compare circadian disparities in the delivery of primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) according to the patient's age and gender. METHODS We investigated patients included into the Acute Myocardial Infarction in Switzerland (AMIS) registry presenting to one of 11 centers in Switzerland providing primary PCI around the clock, and stratified patients according to gender and age. FINDINGS A total of 4723 patients presented with AMI between 2005 and 2010; 1319 (28%) were women and 2172 (54%) were ≥65 years of age. More than 90% of patients <65 years of age underwent primary PCI without differences between gender. Elderly patients and particularly women were at increased risk of being withheld primary PCI (males adj. HR 4.91, 95% CI 3.93-6.13; females adj. HR 9.31, 95% CI 7.37-11.75) as compared to males <65 years of age. An increased risk of a delay in door-to-balloon time >90 minutes was found in elderly males (adj HR 1.66 (95% CI 1.40-1.95), p<0.001) and females (adj HR 1.57 (95% CI 1.27-1.93), p<0.001), as well as in females <65 years (adj HR 1.47 (95% CI 1.13-1.91), p = 0.004) as compared to males <65 years of age, with significant differences in circadian patterns during on- and off-duty hours. CONCLUSIONS In a cohort of patients with AMI in Switzerland, we observed discrimination of elderly patients and females in the circadian provision of primary PCI.