125 research outputs found

    Comparing amine- and ammonium functionalized silsesquioxanes for large scale synthesis of hybrid polyimide high-temperature gas separation membranes

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    PolyPOSS-imide membranes are promising for separating H2 from larger molecules (CO2, N2, CH4) at temperatures up to 300 °C. Their fabrication involves two steps: interfacial polymerization of POSS and 6FDA, followed by thermal imidization. This work provides a systematic study of the effects of cations on membrane properties and performance. For this, two distinct POSS molecules were used: functionalized with -NH3+Cl− or, so far unexplored, -NH2. The ammonium groups are partially deprotonated by using three different bases, LiOH, NaOH, and KOH. We demonstrate that the introduced cations affect the film thickness but not the molecular composition of the polyamic acid. All polyamic acids can be imidized, but the cations reduce the imidization kinetics as well as the loss of organic crosslinkers. For flat disc membranes, at 200 °C, the absence of cations results in comparable permeability combined with higher selectivity for H2/N2. This, and the possibility to discard adding a base, motivated a scale-up study of the new POSS. For tubular membranes, much higher ideal and mixed gas selectivities are found than for membranes where NaOH was added. Results indicate that the new route allows more reproducible production of defect free membranes and has potential for larger-scale polyPOSSimide fabrication.publishedVersio

    Diagnose, indicate, and treat severe mental illness (DITSMI) as appropriate care: A three-year follow-up study in long-term residential psychiatric patients on the effects of re-diagnosis on medication prescription, patient functioning, and hospital bed utilization

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    BACKGROUND.: While polypharmacy is common in long-term residential psychiatric patients, prescription combinations may, from an evidence-based perspective, be irrational. Potentially, many psychiatric patients are treated on the basis of a poor diagnosis. We therefore evaluated the DITSMI model (i.e., Diagnose, Indicate, and Treat Severe Mental Illness), an intervention that involves diagnosis (or re-

    Chronic exposure of gingival fibroblasts to TLR2 or TLR4 agonist inhibits osteoclastogenesis but does not affect osteogenesis

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    Chronic exposure to periodontopathogenic bacteria such as Porphyromonas gingivalis and the products of these bacteria that interact with the cells of the tooth surrounding tissues can ultimately result in periodontitis. This is a disease that is characterized by inflammation-related alveolar bone degradation by the bone-resorbing cells, the osteoclasts. Interactions of bacterial products with Toll-like receptors (TLRs), in particular TLR2 and TLR4, play a significant role in this chronic inflammatory reaction, which possibly affects osteoclastic activity and osteogenic capacity. Little is known about how chronic exposure to specific TLR activators affects these two antagonistic activities. Here, we studied the effect of TLR activation on gingival fibroblasts (GF), cells that are anatomically close to infiltrating bacterial products in the mouth. These were co-cultured with naive osteoclast precursor cells (i.e., monocytes), as part of the peripheral blood mononuclear cells (PBMCs). Activation of GF co-cultures (GF + PBMCs) with TLR2 or TLR4 agonists resulted in a weak reduction of the osteoclastogenic potential of these cultures, predominantly due to TLR2. Interestingly, chronic exposure, especially to TLR2 agonist, resulted in increased release of TNF-α at early time points. This effect, was reversed at later time points, thus suggesting an adaptation to chronic exposure. Monocyte cultures primed with M-CSF + RANKL, led to the formation of bone-resorbing osteoclasts, irrespective of being activated with TLR agonists. Late activation of these co-cultures with TLR2 and with TLR4 agonists led to a slight decrease in bone resorption. Activation of GF with TLR2 and TLR4 agonists did not affect the osteogenic capacity of the GF cells. In conclusion, chronic exposure leads to diverse reactions; inhibitory with naive osteoclast precursors, not effecting already formed (pre-)osteoclasts. We suggest that early encounter of naive monocytes with TLR agonists may result in differentiation toward the macrophage lineage, desirable for clearing bacterial products. Once (pre-)osteoclasts are formed, these cells may be relatively insensitive for direct TLR stimulation. Possibly, TLR activation of periodontal cells indirectly stimulates osteoclasts, by secreting osteoclastogenesis stimulating inflammatory cytokines

    Interfering with DNA Decondensation as a Strategy Against Mycobacteria

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    Tuberculosis is once again a major global threat, leading to more than 1 million deaths each year. Treatment options for tuberculosis patients are limited, expensive and characterized by severe side effects, especially in the case of multidrug-resistant forms. Uncovering novel vulnerabilities of the pathogen is crucial to generate new therapeutic strategies. Using high resolution microscopy techniques, we discovered one such vulnerability of Mycobacterium tuberculosis. We demonstrate that the DNA of M. tuberculosis can condense under stressful conditions such as starvation and antibiotic treatment. The DNA condensation is reversible and specific for viable bacteria. Based on these observations, we hypothesized that blocking the recovery from the condensed state could weaken the bacteria. We showed that after inducing DNA condensation, and subsequent blocking of acetylation of DNA binding proteins, the DNA localization in the bacteria is altered. Importantly under these conditions, Mycobacterium smegmatis did not replicate and its survival was significantly reduced. Our work demonstrates that agents that block recovery from the condensed state of the nucleoid can be exploited as antibiotic. The combination of fusidic acid and inhibition of acetylation of DNA binding proteins, via the Eis enzyme, potentiate the efficacy of fusidic acid by 10 and the Eis inhibitor to 1,000-fold. Hence, we propose that successive treatment with antibiotics and drugs interfering with recovery from DNA condensation constitutes a novel approach for treatment of tuberculosis and related bacterial infections

    The MEF2 transcriptional target DMPK induces loss of sarcomere structure and cardiomyopathy

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    Aims The pathology of heart failure is characterized by poorly contracting and dilated ventricles. At the cellular level, this is associated with lengthening of individual cardiomyocytes and loss of sarcomeres. While it is known that the transcription factor myocyte enhancer factor-2 (MEF2) is involved in this cardiomyocyte remodelling, the underlying mechanism remains to be elucidated. Here, we aim to mechanistically link MEF2 target genes with loss of sarcomeres during cardiomyocyte remodelling. Methods Neonatal rat cardiomyocytes overexpressing MEF2 elongated and lost their sarcomeric structure. We identified and results myotonic dystrophy protein kinase (DMPK) as direct MEF2 target gene involved in this process. Adenoviral overexpression of DMPK E, the isoform upregulated in heart failure, resulted in severe loss of sarcomeres in vitro, and transgenic mice overexpressing DMPK E displayed disruption of sarcomere structure and cardiomyopathy in vivo. Moreover, we found a decreased expression of sarcomeric genes following DMPK E gain-of-function. These genes are targets of the transcription factor serum response factor (SRF) and we found that DMPK E acts as inhibitor of SRF transcriptional activity. Conclusion Our data indicate that MEF2-induced loss of sarcomeres is mediated by DMPK via a decrease in sarcomeric gene expression by interfering with SRF transcriptional activity. Together, these results demonstrate an unexpected role for DMPK as a direct mediator of adverse cardiomyocyte remodelling and heart failure

    Surgical quality and prospective quality control of the D2-gastrectomy for gastric cancer in the multicenter randomized LOGICA-trial

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    Background: Quality of gastric cancer surgery is crucial for favorable prognosis. Generally, prospective trials lack quality control measures. This study assessed surgical quality and a novel D2-lymphadenectomy photo-scoring in the LOGICA-trial. Methods: The multicenter LOGICA-trial randomized laparoscopic versus open total/distal D2-gastrectomy for resectable gastric cancer (cT1-4aN0-3M0) in 10 Dutch hospitals. During the trial, two reviewers prospectively analyzed intraoperative photographs of dissected nodal stations for quality control, and provided centers weekly feedback on their D2-lymphadenectomy, as continuous quality-enhancing incentive. After the trial, these photographs were reanalyzed to develop a photo-scoring for future trials, rating the D2-lymphadenectomy dissection quality (optimal-good-suboptimal-unevaluable). Interobserver variability was calculated (weighted kappa). Regression analyses related the photo-scoring to nodal yield, recurrence and 5-years survival. Results: Between 2015 and 2018, 212 patients underwent total/distal D2-gastrectomy (n = 122/n = 90), and 158 (75%) received neoadjuvant chemotherapy. R0-resection rate was 95%. Rate of ≄15 retrieved lymph nodes was 95%. Moderate agreement was obtained in stations 8 + 9 (Îș = 0.522), 11p/11d (Îș = 0.446) and 12a (Îș = 0.441). Consensus was reached for discordant cases (30%). Stations 8 + 9, 11p/11d and 12a were rated ‘optimal’ in 76%, 63% and 68%. Laparoscopic photographs could be rated better than open (2% versus 12% ‘unevaluable’; 73% versus 50% ‘optimal’; p = 0.042). The photo-scoring did not show associations with nodal yield (p = 0.214), recurrence (p = 0.406) and survival (p = 0.988). Conclusions: High radicality and nodal yield demonstrated good quality of D2-gastrectomy. The prospective quality control probably contributed to this. The photo-scoring did not show good performance, but can be refined. Laparoscopic D2-gastrectomy was better suited for standardized surgical photo-evaluation than open surgery.</p

    Body Composition Is a Predictor for Postoperative Complications After Gastrectomy for Gastric Cancer:a Prospective Side Study of the LOGICA Trial

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    PURPOSE: There is a lack of prospective studies evaluating the effects of body composition on postoperative complications after gastrectomy in a Western population with predominantly advanced gastric cancer. METHODS: This is a prospective side study of the LOGICA trial, a multicenter randomized trial on laparoscopic versus open gastrectomy for gastric cancer. Trial patients who received preoperative chemotherapy followed by gastrectomy with an available preoperative restaging abdominal computed tomography (CT) scan were included. The CT scan was used to calculate the mass (M) and radiation attenuation (RA) of skeletal muscle (SM), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT). These variables were expressed as Z-scores, depicting how many standard deviations each patient’s CT value differs from the sex-specific study sample mean. Primary outcome was the association of each Z-score with the occurrence of a major postoperative complication (Clavien-Dindo grade ≄ 3b). RESULTS: From 2015 to 2018, a total of 112 patients were included. A major postoperative complication occurred in 9 patients (8%). A high SM-M Z-score was associated with a lower risk of major postoperative complications (RR 0.47, 95% CI 0.28–0.78, p = 0.004). Furthermore, high VAT-RA Z-scores and SAT-RA Z-scores were associated with a higher risk of major postoperative complications (RR 2.82, 95% CI 1.52–5.23, p = 0.001 and RR 1.95, 95% CI 1.14–3.34, p = 0.015, respectively). VAT-M, SAT-M, and SM-RA Z-scores showed no significant associations. CONCLUSION: Preoperative low skeletal muscle mass and high visceral and subcutaneous adipose tissue radiation attenuation (indicating fat depleted of triglycerides) were associated with a higher risk of developing a major postoperative complication in patients treated with preoperative chemotherapy followed by gastrectomy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11605-022-05321-0

    Pain and Opioid Consumption After Laparoscopic Versus Open Gastrectomy for Gastric Cancer:A Secondary Analysis of a Multicenter Randomized Clinical Trial (LOGICA-Trial)

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    Background:Laparoscopic gastrectomy could reduce pain and opioid consumption, compared to open gastrectomy. However, it is difficult to judge the clinical relevance of this reduction, since these outcomes are reported in few randomized trials and in limited detail. Methods: This secondary analysis of a multicenter randomized trial compared laparoscopic versus open gastrectomy for resectable gastric adenocarcinoma (cT1-4aN0-3bM0). Postoperative pain was analyzed by opioid consumption in oral morphine equivalents (OME, mg/day) at postoperative day (POD) 1–5, WHO analgesic steps, and Numeric Rating Scales (NRS, 0–10) at POD 1–10 and discharge. Regression and mixed model analyses were performed, with and without correction for epidural analgesia. Results: Between 2015 and 2018, 115 patients in the laparoscopic group and 110 in the open group underwent surgery. Some 16 patients (14%) in the laparoscopic group and 73 patients (66%) in the open group received epidural analgesia. At POD 1–3, mean opioid consumption was 131, 118, and 53 mg OME lower in the laparoscopic group, compared to the open group, respectively (all p &lt; 0.001). After correcting for epidural analgesia, these differences remained significant at POD 1–2 (47 mg OME, p = 0.002 and 69 mg OME, p &lt; 0.001, respectively). At discharge, 27% of patients in the laparoscopic group and 43% patients in the open group used oral opioids (p = 0.006). Mean highest daily pain scores were between 2 and 4 at all PODs, &lt; 2 at discharge, and did not relevantly differ between treatment arms. Conclusion: In this multicenter randomized trial, postoperative pain was comparable between laparoscopic and open gastrectomy. After laparoscopic gastrectomy, this was generally achieved without epidural analgesia and with fewer opioids. Trial Registration: NCT02248519.</p

    Soil networks become more connected and take up more carbon as nature restoration progresses

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    Soil organisms have an important role in aboveground community dynamics and ecosystem functioning in terrestrial ecosystems. However, most studies have considered soil biota as a black box or focussed on specific groups, whereas little is known about entire soil networks. Here we show that during the course of nature restoration on abandoned arable land a compositional shift in soil biota, preceded by tightening of the belowground networks, corresponds with enhanced efficiency of carbon uptake. In mid- and long-term abandoned field soil, carbon uptake by fungi increases without an increase in fungal biomass or shift in bacterial-to-fungal ratio. The implication of our findings is that during nature restoration the efficiency of nutrient cycling and carbon uptake can increase by a shift in fungal composition and/or fungal activity. Therefore, we propose that relationships between soil food web structure and carbon cycling in soils need to be reconsidered

    Chromatic periodic activity down to 120 MHz in a Fast Radio Burst

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    Fast radio bursts (FRBs) are extragalactic astrophysical transients whose brightness requires emitters that are highly energetic, yet compact enough to produce the short, millisecond-duration bursts. FRBs have thus far been detected between 300 MHz and 8 GHz, but lower-frequency emission has remained elusive. A subset of FRBs is known to repeat, and one of those sources, FRB 20180916B, does so with a 16.3 day activity period. Using simultaneous Apertif and LOFAR data, we show that FRB 20180916B emits down to 120 MHz, and that its activity window is both narrower and earlier at higher frequencies. Binary wind interaction models predict a narrower periodic activity window at lower frequencies, which is the opposite of our observations. Our detections establish that low-frequency FRB emission can escape the local medium. For bursts of the same fluence, FRB 20180916B is more active below 200 MHz than at 1.4 GHz. Combining our results with previous upper-limits on the all-sky FRB rate at 150 MHz, we find that there are 3-450 FRBs/sky/day above 50 Jy ms at 90% confidence. We are able to rule out the scenario in which companion winds cause FRB periodicity. We also demonstrate that some FRBs live in clean environments that do not absorb or scatter low-frequency radiation.Comment: 50 pages, 14 figures, 3 tables, submitte
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