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- Dey, Lankeswar, et al.
(författare)
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Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare : Improved Orbital Parameters
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 866:1
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Tidskriftsartikel (refereegranskat)abstract
- Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole no-hair theorem at the 10% level.
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| 8. |
- Meyer, L, et al.
(författare)
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Thrombectomy for secondary distal, medium vessel occlusions of the posterior circulation: seeking complete reperfusion
- 2022
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Ingår i: Journal of neurointerventional surgery. - : BMJ. - 1759-8486 .- 1759-8478. ; 14:7, s. 654-659
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Tidskriftsartikel (refereegranskat)abstract
- Whether to approach distal occlusions endovascularly or not in medium-sized vessels secondary to proximal large vessel occlusion stroke remains unanswered.ObjectiveTo investigates the technical feasibility and safety of thrombectomy for secondary posterior circulation distal, medium vessel occlusions (DMVO).MethodsTOPMOST (Treatment fOr Primary Medium vessel Occlusion STroke) is an international, retrospective, multicenter, observational registry of patients treated for distal cerebral artery occlusions. This study subanalysis endovascularly treated occlusions of the posterior cerebral artery in the P2 and P3 segment secondary preprocedural or periprocedural thrombus migration between January 2014 and June 2020. Technical feasibility was evaluated with the modified Thrombolysis in Cerebral Infarction (mTICI) scale. Procedural safety was assessed by the occurrence of symptomatic intracranial hemorrhage (sICH) and intervention-related serious adverse events.ResultsAmong 71 patients with secondary posterior circulation DMVO who met the inclusion criteria, occlusions were present in 80.3% (57/71) located in the P2 segment and in 19.7% (14/71) in the P3 segment. Periprocedural migration occurred in 54.9% (39/71) and preprocedural migration in 45.1% (32/71) of cases. The first reperfusion attempt led in 38% (27/71) of all cases to mTICI 3. On multivariable logistic regression analysis, increased numbers of reperfusion attempts (adjusted odds ratio (aOR)=0.39, 95% CI 0.29 to 0.88, p=0.009) and preprocedural migration (aOR=4.70, 95% CI,1.35 to 16.35, p=0.015) were significantly associated with mTICI 3. sICH occurred in 2.8% (2/71).ConclusionThrombectomy for secondary posterior circulation DMVO seems to be safe and technically feasible. Even though thrombi that have migrated preprocedurally may be easier to retract, successful reperfusion can be achieved in the majority of patients with secondary DMVO of the P2 and P3 segment.
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| 9. |
- Gopinathan, L., et al.
(författare)
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Emi2 Is Essential for Mouse Spermatogenesis
- 2017
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 20:3, s. 697-708
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Tidskriftsartikel (refereegranskat)abstract
- The meiotic functions of Emi2, an inhibitor of the APC/C complex, have been best characterized in oocytes where it mediates metaphase II arrest as a component of the cytostatic factor. We generated knockout mice to determine the in vivo functions of Emi2-in particular, its functions in the testis, where Emi2 is expressed at high levels. Male and female Emi2 knockout mice are viable but sterile, indicating that Emi2 is essential for meiosis but dispensable for embryonic development and mitotic cell divisions. We found that, besides regulating cell-cycle arrest in mouse eggs, Emi2 is essential for meiosis I progression in spermatocytes. In the absence of Emi2, spermatocytes arrest in early diplotene of prophase I. This arrest is associated with decreased Cdk1 activity and was partially rescued by a knockin mouse model of elevated Cdk1 activity. Additionally, we detected expression of Emi2 in spermatids and sperm, suggesting potential post-meiotic functions for Emi2.
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| 11. |
- Strittmatter, Nicole, et al.
(författare)
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Method To Visualize the Intratumor Distribution and Impact of Gemcitabine in Pancreatic Ductal Adenocarcinoma by Multimodal Imaging
- 2022
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 94:3, s. 1795-1803
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Tidskriftsartikel (refereegranskat)abstract
- Gemcitabine (dFdC) is a common treatment for pancreatic cancer; however, it is thought that treatment may fail because tumor stroma prevents drug distribution to tumor cells. Gemcitabine is a pro-drug with active metabolites generated intracellularly; therefore, visualizing the distribution of parent drug as well as its metabolites is important. A multimodal imaging approach was developed using spatially coregistered mass spectrometry imaging (MSI), imaging mass cytometry (IMC), multiplex immunofluorescence microscopy (mIF), and hematoxylin and eosin (H&E) staining to assess the local distribution and metabolism of gemcitabine in tumors from a genetically engineered mouse model of pancreatic cancer (KPC) allowing for comparisons between effects in the tumor tissue and its microenvironment. Mass spectrometry imaging (MSI) enabled the visualization of the distribution of gemcitabine (100 mg/kg), its phosphorylated metabolites dFdCMP, dFdCDP and dFdCTP, and the inactive metabolite dFdU. Distribution was compared to small-molecule ATR inhibitor AZD6738 (25 mg/kg), which was codosed. Gemcitabine metabolites showed heterogeneous distribution within the tumor, which was different from the parent compound. The highest abundance of dFdCMP, dFdCDP, and dFdCTP correlated with distribution of endogenous AMP, ADP, and ATP in viable tumor cell regions, showing that gemcitabine active metabolites are reaching the tumor cell compartment, while AZD6738 was located to nonviable tumor regions. The method revealed that the generation of active, phosphorylated dFdC metabolites as well as treatment-induced DNA damage primarily correlated with sites of high proliferation in KPC PDAC tumor tissue, rather than sites of high parent drug abundance.
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- Niska-Blakie, Joanna, et al.
(författare)
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Knockout of the non-essential gene SUGCT creates diet-linked, age-related microbiome disbalance with a diabetes-like metabolic syndrome phenotype
- 2019
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Ingår i: Cellular and Molecular Life Sciences. - : Springer Science and Business Media LLC. - 1420-682X .- 1420-9071.
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Tidskriftsartikel (refereegranskat)abstract
- SUGCT (C7orf10) is a mitochondrial enzyme that synthesizes glutaryl-CoA from glutarate in tryptophan and lysine catabolism, but it has not been studied in vivo. Although mutations in Sugct lead to Glutaric Aciduria Type 3 disease in humans, patients remain largely asymptomatic despite high levels of glutarate in the urine. To study the disease mechanism, we generated SugctKO mice and uncovered imbalanced lipid and acylcarnitine metabolism in kidney in addition to changes in the gut microbiome. After SugctKO mice were treated with antibiotics, metabolites were comparable to WT, indicating that the microbiome affects metabolism in SugctKO mice. SUGCT loss of function contributes to gut microbiota dysbiosis, leading to age-dependent pathological changes in kidney, liver, and adipose tissue. This is associated with an obesity-related phenotype that is accompanied by lipid accumulation in kidney and liver, as well as “crown-like” structures in adipocytes. Furthermore, we show that the SugctKO kidney pathology is accelerated and exacerbated by a high-lysine diet. Our study highlights the importance of non-essential genes with no readily detectable early phenotype, but with substantial contributions to the development of age-related pathologies, which result from an interplay between genetic background, microbiome, and diet in the health of mammals.
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| 15. |
- Siow, I, et al.
(författare)
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Bridging Thrombolysis versus Direct Mechanical Thrombectomy in Stroke Due to Basilar Artery Occlusion
- 2022
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Ingår i: Journal of stroke. - : Korean Stroke Society. - 2287-6391 .- 2287-6405. ; 24:1, s. 128-
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose Mechanical thrombectomy (MT) is an effective treatment for patients with basilar artery occlusion (BAO) acute ischemic stroke. It remains unclear whether bridging intravenous thrombolysis (IVT) prior to MT confers any benefit. This study compared the outcomes of acute BAO patients who were treated with direct MT versus combined IVT plus MT.Methods This multicenter retrospective cohort study included patients who were treated for acute BAO from eight comprehensive stroke centers between January 2015 and December 2019. Patients received direct MT or combined bridging IVT plus MT. Primary outcome was favorable functional outcome defined as modified Rankin Scale 0–3 measured at 90 days. Secondary outcome measures included mortality and symptomatic intracranial hemorrhage (sICH).Results Among 322 patients, 127 (39.4%) patients underwent bridging IVT followed by MT and 195 (60.6%) underwent direct MT. The mean±standard deviation age was 67.5±14.1 years, 64.0% were male and median National Institutes of Health Stroke Scale was 16 (interquartile range, 8 to 25). At 90-day, the rate of favorable functional outcome was similar between the bridging IVT and direct MT groups (39.4% vs. 34.4%, P=0.361). On multivariable analyses, bridging IVT was not as Comorbidisociated with favorable functional outcome, mortality or sICH. In subgroup analyses, patients with underlying atherosclerosis treated with bridging IVT compared to direct MT had a higher rate of favorable functional outcome at 90 days (37.2% vs. 15.5%, P=0.013).Conclusions Functional outcomes were similar in BAO patients treated with bridging IVT versus direct MT. In the subgroup of patients with underlying large-artery atherosclerosis stroke mechanism, bridging IVT may potentially confer benefit and this warrants further investigation.
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| 16. |
- Sugawara, Yuuki, et al.
(författare)
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Anion Exchange Membrane Water Electrolyzers: An Overview
- 2023
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Ingår i: Journal of Chemical Engineering of Japan. - 0021-9592. ; 56:1
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Forskningsöversikt (refereegranskat)abstract
- The green-H-2 production through water electrolysis from renewable energies is vital in the context of developing a sustainable and cost-effective methodology. Anion exchange membrane water electrolyzer (AEMWE) is considered as a promising energy conversion device, which can be an alternative to fossil fuel-based energyplatforms. AEMWE can employ inexpensive nonprecious metal catalysts and current collectors, which is preferable forpractical applications of this technology. Membrane electrode assemblies (MEAs) for AEMWE plays a significant role forthe hydrogen production efficiency. Thus, understanding the MEA components, operation, and performance is critical forthe development of prominent materials for the AEMWE. In this review, we highlight the performances of the MEAs andtheir components, such as the AEMs and catalysts with a broad discussion of the progress with current status. Additionally,we also have put forward our assessment to lead the way for future research, to commercialize AEMWE as a provenalternative for the cost-effective production of high-purity hydrogen.
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| 18. |
- Tan, BYQ, et al.
(författare)
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Effect of Sex on Outcomes of Mechanical Thrombectomy in Basilar Artery Occlusion: A Multicentre Cohort Study
- 2022
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Ingår i: Cerebrovascular diseases (Basel, Switzerland). - : S. Karger AG. - 1421-9786 .- 1015-9770. ; 51:5, s. 639-646
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Tidskriftsartikel (refereegranskat)abstract
- <b><i>Introduction:</i></b> Identifying differences in outcome of basilar artery occlusion (BAO) between males and females may be useful in aiding clinical management. Recent studies have demonstrated widespread underrepresentation of women in acute stroke clinical trials. This international multicentre study aimed to determine sex differences in outcome after mechanical thrombectomy (MT) for patients with acute BAO. <b><i>Methods:</i></b> We performed a retrospective analysis of consecutive patients with BAO who had undergone MT in seven stroke centres across five countries (Singapore, Taiwan, United Kingdom, Sweden, and Germany), between 2015 and 2020. Primary outcome was a favourable functional outcome measured by a modified Ranking Scale (mRS) of 0–3 at 90 days. Secondary outcomes were mRS 0–3 upon discharge, mortality, symptomatic intracranial haemorrhage (sICH) and subarachnoid haemorrhage (SAH). <b><i>Results:</i></b> Among the 322 patients who underwent MT, 206 (64.0%) patients were male and 116 (36.0%) were female. Females were older than males (mean ± SD 70.9 ± 14.3 years vs. 65.6 ± 133.6 years; <i>p</i> = 0.001) and had higher rates of atrial fibrillation (38.9% vs. 24.2%; <i>p</i> = 0.012). Time from groin puncture to reperfusion was shorter in females than males (mean ± SD 57.2 ± 37.2 min vs. 71.1 ± 50.9 min; <i>p</i> = 0.021). Despite these differences, primary and secondary outcome measures were similar in females and males, with comparable rates of favourable 90-day mRS scores (mean ± SD 46 ± 39.7 vs. 71 ± 34.5; OR = 1.20; 95% confidence interval [CI] = 0.59–2.43; <i>p</i> = 0.611), favourable discharge mRS scores (mean ± SD 39 ± 31.6 vs. 43 ± 25.9; OR = 1.38; 95% CI = 0.69–2.78; <i>p</i> = 0.368) and in-hospital mortality (mean ± SD 30 ± 25.9 vs. 47 ± 22.8; OR = 1.15; 95% CI = 0.55–2.43; <i>p</i> = 0.710. Rates of complications such as sICH (mean ± SD 5 ± 4.3 vs. 9 ± 4.4; OR = 0.46; 95% CI = 0.08–2.66; <i>p</i> = 0.385) and SAH (mean ± SD 4 ± 3.4 vs. 5 ± 2.4; OR = 0.29; 95% CI = 0.03–3.09; <i>p</i> = 0.303) comparably low in both groups. <b><i>Conclusion:</i></b> Females achieved comparable functional outcomes compared with males after undergoing MT for BAO acute ischemic stroke.
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| 20. |
- Yeo, LLL, et al.
(författare)
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Posterior communicating and anterior communicating arteries on pre-thrombectomy computed tomography scans are associated with good outcomes irrespective of leptomeningeal collateral status
- 2019
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Ingår i: Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences. - : SAGE Publications. - 2385-2011. ; 25:4, s. 364-370
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Tidskriftsartikel (refereegranskat)abstract
- Collateral blood flow is known to be an important factor that sustains the penumbra during acute stroke. We looked at both the leptomeningeal collateral circulation and the presence of anterior and posterior communicating arteries to determine the factors associated with good outcomes and mortality. Methods We included all patients with acute ischaemic stroke in the anterior circulation, who underwent thrombectomy with the same thrombectomy device from 2013 to 2016. We assessed the leptomeningeal circulation by the Tan, Miteff and Maas validated scoring systems on pre-treatment computed tomographic angiography scans and looked at collateral flow through anterior and posterior communicating arteries. The results were good functional outcomes at 3 months (modified Rankin scale 0–2) and mortality. Results A total of 147 consecutive acute stroke patients treated with the Embotrap device were included with a median National Institutes of Health stroke scale of 15 (range 2–26). On multivariate analysis only younger age (odds ratio (OR) 0.96/year, 95% confidence interval (CI) 0.94–0.99, P = 0.026), lower National Institutes of Health stroke scale score (OR 0.87/point, 95% CI 0.80–0.93, P < 0.001), number of attempts (OR 0.80/attempt, 95% CI 0.65–0.99, P = 0.043) and the presence of a patent anterior communicating artery (OR 14.03, 95% CI 1.42–139.07, P = 0.024) were associated with good functional outcomes. The number of attempts (OR 1.66/attempt, 95% CI 1.21–2.29, P = 0.002) was significantly associated with mortality and the presence of a patent posterior communicating artery (OR 0.098, 95% CI 0.016–0.59, P = 0.011) was inversely associated with mortality. Conclusions Our study shows that the presence of anterior and posterior communicating arteries is significantly associated with good functional outcomes and reduced mortality, respectively, independent of the leptomeningeal circulation status.
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