260 research outputs found

    C58 on Au(111): a scanning tunneling microscopy study

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    C58 fullerenes were adsorbed onto room temperature Au(111) surface by low-energy (~6 eV) cluster ion beam deposition under ultrahigh vacuum conditions. The topographic and electronic properties of the deposits were monitored by means of scanning tunnelling microscopy (STM at 4.2 K). Topographic images reveal that at low coverages fullerene cages are pinned by point dislocation defects on the herringbone reconstructed gold terraces (as well as by step edges). At intermediate coverages, pinned monomers, act as nucleation centres for the formation of oligomeric C58 chains and 2D islands. At the largest coverages studied, the surface becomes covered by 3D interlinked C58 cages. STM topographic images of pinned single adsorbates are essentially featureless. The corresponding local densities of states are consistent with strong cage-substrate interactions. Topographic images of [C58]n oligomers show a stripe-like intensity pattern oriented perpendicular to the axis connecting the cage centers. This striped pattern becomes even more pronounced in maps of the local density of states. As supported by density functional theory, DFT calculations, and also by analogous STM images previously obtained for C60 polymers (M. Nakaya et al., J. Nanosci. Nanotechnol. 11, 2829 (2011)), we conclude that these striped orbital patterns are a fingerprint of covalent intercage bonds. For thick C58 films we have derived a band gap of 1.2 eV from scanning tunnelling spectroscopy data, STS, confirming that the outermost C58 layer behaves as a wide band semiconductor

    Circuit-selective cell-autonomous regulation of inhibition in pyramidal neurons by Ste20-like kinase

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    Maintaining an appropriate balance between excitation and inhibition is critical for neuronal information processing. Cortical neurons can cell-autonomously adjust the inhibition they receive to individual levels of excitatory input, but the underlying mechanisms are unclear. We describe that Ste20-like kinase (SLK) mediates cell-autonomous regulation of excitation-inhibition balance in the thalamocortical feedforward circuit, but not in the feedback circuit. This effect is due to regulation of inhibition originating from parvalbumin-expressing interneurons, while inhibition via somatostatin-expressing interneurons is unaffected. Computational modeling shows that this mechanism promotes stable excitatory-inhibitory ratios across pyramidal cells and ensures robust and sparse coding. Patch-clamp RNA sequencing yields genes differentially regulated by SLK knockdown, as well as genes associated with excitation-inhibition balance participating in transsynaptic communication and cytoskeletal dynamics. These data identify a mechanism for cell-autonomous regulation of a specific inhibitory circuit that is critical to ensure that a majority of cortical pyramidal cells participate in information coding

    The Metabolic Health Index Identifies Patients That Will Benefit From Metabolic Surgery

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    Introduction: Metabolic syndrome is a modern world's major health hazard related to comorbidities like type 2 diabetes and cardiovascular disease. Bariatric surgery is well known to lower this health risk in patients with obesity. There is a need for an objective measure to assess the intended reduction in health hazard and indirectly the eligibility for bariatric surgery. The Metabolic Health Index (MHI) quantitatively summarizes the cumulative impact of the metabolic syndrome on health status on a scale from 1 to 6. This study describes the use of the MHI as a supportive tool in the decision for and outcome assessment of bariatric surgery. Methods: The general usability of the MHI was tested by extending its application to patient data of five other bariatric centers in the Netherlands. Retrospective laboratory and national bariatric quality registry data of 11,501 patients were collected. Results: The quantification of (improvement in) metabolic health burden as measured by the MHI was independent of the dataset that was used to derive the MHI model. Patients with MHI &gt; 2.8 prior to surgery improved significantly more in MHI 12 mo after surgery compared to patients with MHI ≤ 2.8 (1.1 compared to 0.4 MHI points, respectively; P &lt; 0.001). Conclusions: The MHI is robust between centers and is suitable for general use in clinical decision-making. As changes in MHI over time reflect metabolic health alterations, it is suitable as an outcome measure of surgery. An MHI cut-off value of 2.8 helps to predict the likelihood of significant improvement after surgery, independent of body mass index and known metabolic comorbidities.</p

    The Metabolic Health Index Identifies Patients That Will Benefit From Metabolic Surgery

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    Introduction: Metabolic syndrome is a modern world's major health hazard related to comorbidities like type 2 diabetes and cardiovascular disease. Bariatric surgery is well known to lower this health risk in patients with obesity. There is a need for an objective measure to assess the intended reduction in health hazard and indirectly the eligibility for bariatric surgery. The Metabolic Health Index (MHI) quantitatively summarizes the cumulative impact of the metabolic syndrome on health status on a scale from 1 to 6. This study describes the use of the MHI as a supportive tool in the decision for and outcome assessment of bariatric surgery. Methods: The general usability of the MHI was tested by extending its application to patient data of five other bariatric centers in the Netherlands. Retrospective laboratory and national bariatric quality registry data of 11,501 patients were collected. Results: The quantification of (improvement in) metabolic health burden as measured by the MHI was independent of the dataset that was used to derive the MHI model. Patients with MHI &gt; 2.8 prior to surgery improved significantly more in MHI 12 mo after surgery compared to patients with MHI ≤ 2.8 (1.1 compared to 0.4 MHI points, respectively; P &lt; 0.001). Conclusions: The MHI is robust between centers and is suitable for general use in clinical decision-making. As changes in MHI over time reflect metabolic health alterations, it is suitable as an outcome measure of surgery. An MHI cut-off value of 2.8 helps to predict the likelihood of significant improvement after surgery, independent of body mass index and known metabolic comorbidities.</p

    Long-term effect of sleeve gastrectomy vs Roux-en-Y gastric bypass in people living with severe obesity:a phase III multicentre randomised controlled trial (SleeveBypass)

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    Background: Sleeve gastrectomy is the most performed metabolic surgical procedure worldwide. However, conflicting results offer no clear evidence about its long-term clinical comparability to Roux-en-Y gastric bypass. This study aims to determine their equivalent long-term weight loss effects. Methods: This randomised open-label controlled trial was conducted from 2012 until 2017 in two Dutch bariatric hospitals with a 5-year follow-up (last follow-up July 29th, 2022). Out of 4045 patients, 628 were eligible for metabolic surgery and were randomly assigned to sleeve gastrectomy or Roux-en-Y gastric bypass (intention-to-treat). The primary endpoint was weight loss, expressed by percentage excess body mass index (BMI) loss. The predefined clinically relevant equivalence margin was −13% to 13%. Secondary endpoints included percentage total kilograms weight loss, obesity-related comorbidities, quality of life, morbidity, and mortality. This trial is registered with Dutch Trial Register NTR4741: https://onderzoekmetmensen.nl/nl/trial/25900. Findings: 628 patients were randomised between sleeve gastrectomy (n = 312) and Roux-en-Y gastric bypass (n = 316) (mean age 43 [standard deviation (SD), 11] years; mean BMI 43.5 [SD, 4.7]; 81.8% women). Excess BMI loss at 5 years was 58.8% [95% CI, 55%–63%] after sleeve gastrectomy and 67.1% [95% CI, 63%–71%] after Roux-en-Y gastric bypass (difference 8.3% [95% CI, −12.5% to −4.0%]). This was within the predefined margin (P &lt; 0.001). Total weight loss at 5 years was 22.5% [95% CI, 20.7%–24.3%] after sleeve gastrectomy and 26.0% [95% CI, 24.3%–27.8%] after Roux-en-Y gastric bypass (difference 3.5% [95% CI, −5.2% to −1.7%]). In both groups, obesity-related comorbidities significantly improved after 5 years. Dyslipidaemia improved more frequently after Roux-en-Y gastric bypass (83%, 54/65) compared to sleeve gastrectomy (62%, 44/71) (P = 0.006). De novo gastro-oesophageal reflux disease occurred more frequently after sleeve gastrectomy (16%, 46/288) vs Roux-en-Y gastric bypass (4%, 10/280) (P &lt; 0.001). Minor complications were more frequent after Roux-en-Y gastric bypass (5%, 15/316) compared to sleeve gastrectomy (2%, 5/312). No statistically significant differences in major complications and health-related quality of life were encountered. Interpretation: In people living with obesity grades 2 and 3, sleeve gastrectomy and Roux-en-Y gastric bypass had clinically comparable excess BMI loss according to the predefined definition for equivalence. However, Roux-en-Y gastric bypass showed significantly higher total weight loss and significant advantages in secondary outcomes, including dyslipidaemia and GERD, yet at a higher rate of minor complications. Major complications, other comorbidities, and overall HRQoL did not significantly differ between the groups. Funding: Not applicable.</p

    Esophageal cancer presenting with atrial fibrillation: A case report

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    <p>Abstract</p> <p>Introduction</p> <p>Atrial fibrillation was previously reported in patients with esophageal cancer as a complication of total esophagectomy or photodynamic therapy. Here, we propose that atrial fibrillation may also be caused by external compression of the left atrium by esophageal cancer.</p> <p>Case presentation</p> <p>We present a 58-year-old man who developed atrial fibrillation with rapid ventricular rate in the emergency room while being evaluated for dysphagia and weight loss. Atrial fibrillation lasted less than 12 hours and did not recur. Echocardiogram did not reveal any structural heart disease. A 10-cm, ulcerated mid-esophageal mass was seen during esophagogastroscopy. Microscopic examination showed squamous cell carcinoma. Computed tomography of the chest revealed esophageal thickening compressing the left atrium.</p> <p>Conclusion</p> <p>External compression of the left atrium was previously reported to provoke atrial fibrillation. Similarly, esophageal cancer may precipitate atrial fibrillation by mechanical compression of the left atrium or pulmonary veins, triggering ectopic beats in susceptible patients.</p

    Urban living in healthy Tanzanians is associated with an inflammatory status driven by dietary and metabolic changes

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    Sub-Saharan Africa currently experiences an unprecedented wave of urbanization, which has important consequences for health and disease patterns. This study aimed to investigate and integrate the immune and metabolic consequences of rural or urban lifestyles and the role of nutritional changes associated with urban living. In a cohort of 323 healthy Tanzanians, urban as compared to rural living was associated with a pro-inflammatory immune phenotype, both at the transcript and protein levels. We identified different food-derived and endogenous circulating metabolites accounting for these differences. Serum from urban dwellers induced reprogramming of innate immune cells with higher tumor necrosis factor production upon microbial re-stimulation in an in vitro model of trained immunity. These data demonstrate important shifts toward an inflammatory phenotype associated with an urban lifestyle and provide new insights into the underlying dietary and metabolic factors, which may affect disease epidemiology in sub-Sahara African countries. Rapid urbanization can be associated with adverse health implications. de Mast and colleagues compare urban and rural Tanzanian populations using multi-omics and observe that urbanization is associated with an elevated but reversible inflammatory state

    The gut microbiota is associated with the small intestinal paracellular permeability and the development of the immune system in healthy children during the first two years of life

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    BACKGROUND: The intestinal barrier plays an important role in the defense against infections, and nutritional, endocrine, and immune functions. The gut microbiota playing an important role in development of the gastrointestinal tract can impact intestinal permeability and immunity during early life, but data concerning this problem are scarce. METHODS: We analyzed the microbiota in fecal samples (101 samples in total) collected longitudinally over 24 months from 21 newborns to investigate whether the markers of small intestinal paracellular permeability (zonulin) and immune system development (calprotectin) are linked to the gut microbiota. The results were validated using data from an independent cohort that included the calprotectin and gut microbiota in children during the first year of life. RESULTS: Zonulin levels tended to increase for up to 6 months after childbirth and stabilize thereafter remaining at a high level while calprotectin concentration was high after childbirth and began to decline from 6 months of life. The gut microbiota composition and the related metabolic potentials changed during the first 2 years of life and were correlated with zonulin and calprotectin levels. Faecal calprotectin correlated inversely with alpha diversity (Shannon index, r = − 0.30, FDR P (Q) = 0.039). It also correlated with seven taxa; i.a. negatively with Ruminococcaceae (r = − 0.34, Q = 0.046), and Clostridiales (r = − 0.34, Q = 0.048) and positively with Staphylococcus (r = 0.38, Q = 0.023) and Staphylococcaceae (r = 0.35, Q = 0.04), whereas zonulin correlated with 19 taxa; i.a. with Bacillales (r = − 0.52, Q = 0.0004), Clostridiales (r = 0.48, Q = 0.001) and the Ruminococcus (torques group) (r = 0.40, Q = 0.026). When time intervals were considered only changes in abundance of the Ruminococcus (torques group) were associated with changes in calprotectin (β = 2.94, SE = 0.8, Q = 0.015). The dynamics of stool calprotectin was negatively associated with changes in two MetaCyc pathways: pyruvate fermentation to butanoate (β = − 4.54, SE = 1.08, Q = 0.028) and Clostridium acetobutylicum fermentation (β = − 4.48, SE = 1.16, Q = 0.026). CONCLUSIONS: The small intestinal paracellular permeability, immune system-related markers and gut microbiota change dynamically during the first 2 years of life. The Ruminococcus (torques group) seems to be especially involved in controlling paracellular permeability. Staphylococcus, Staphylococcaceae, Ruminococcaceae, and Clostridiales, may be potential biomarkers of the immune system. Despite observed correlations their clear causation and health consequences were not proven. Mechanistic studies are required

    Deterministic Encoding and Hashing to Odd Hyperelliptic Curves

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    The original publication is available at www.springerlink.comInternational audienceIn this paper we propose a very simple and efficient encoding function from Fq to points of a hyperelliptic curve over Fq of the form H : y2 = f(x) where f is an odd polynomial. Hyperelliptic curves of this type have been frequently considered in the literature to obtain Jacobians of good order and pairing-friendly curves. Our new encoding is nearly a bijection to the set of Fq -rational points on H . This makes it easy to construct well-behaved hash functions to the Jacobian J of H , as well as injective maps to J (Fq ) which can be used to encode scalars for such applications as ElGamal encryption. The new encoding is already interesting in the genus 1 case, where it provides a well-behaved encoding to Joux?s supersingular elliptic curves
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