192 research outputs found

    Utilization of sidestreams in rubbers

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    The environmental aspect is highlighted more and more every day in all fields of industry. The environmental aspects need to be noted in used techniques as well as in used raw materials. The utilization of different sidestream materials and wastes is the future also in rubber industries. The focus of the present work is on unconventional filler materials in rubber compounds. The theoretical part is comprised basic rubber theory, to help understand the rest of the work better, and a review of researches about unconventional filler materials in different rubbers. The rubber theory includes the presentation of the most commonly used elastomers, fillers, and other additional materials in rubber compounds as well as the basis of rubber compounding. In the review chapter, many different kinds of materials studied as a filler for rubber are discussed. Majority of the studied materials proved to be non-reinforcing fillers and no major property improvements were noted. None of the studied materials showed properties that could replace the most used commercial reinforcing filler, carbon black. Several possibilities as non-reinforcing filler were noted with unconventional fillers, but further research is needed. In the experimental part, the aim was to find out properties of the selected sidestream materials in rubbers. Three different materials were compounded with natural rubber and EPDM with different quantities and compared to reference compounds. Mechanical properties such as tensile properties, tear strength, and hardness, and processability such as curing characteristics, Mooney viscosity, and The Payne effect was tested. From the results it can be concluded that none of the studied materials worked as a reinforcing filler and thus could not replace carbon black as a filler in rubbers. Processability with all the studied materials was good or adequate. The main reason of the studied materials for not working as a reinforcing filler was their too large particle size. Some potential as a cost reducing filler was noted but further research is needed to unveil other effective properties and to determine potential applications

    Variation in Hsp70 Levels after Cold Shock: Signs of Evolutionary Responses to Thermal Selection among Leptinotarsa decemlineata Populations

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    Individuals of widely spread species are expected to show local adaption in temperature tolerance as they encounter a range of thermal conditions. We tracked thermal adaptations of the Colorado potato beetle (Leptinotarsa decemlineata) that invaded Europe within the last 100 years. It has occupied various conditions although, like the majority of invasive species, it lost a measurable amount of neutral genetic variation due to bottleneck effect when it invaded Europe. We exposed diapausing beetles originated from three different latitudes (54°N, 59°N, 60°N) to cold shock (−5°C, 1.5 hrs) in order to test if beetles from the northern populations express differential levels of cold-induced and constitutive Hsp70 compared to the beetles from milder temperature regime. The level of cold-induced Hsp70 was lowest in the northernmost beetle populations while the level of constitutive Hsp70 did not differ with the population. Moreover, the southernmost beetles were more plastic in their response to cold shock than the northernmost beetles. These results suggest that physiological adaptation, like the synthesis of Hsp70, can evolve very quickly

    Adaptation to fluctuations in temperature by nine species of bacteria

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    Rapid environmental fluctuations are ubiquitous in the wild, yet majority of experimental studies mostly consider effects of slow fluctuations on organism. To test the evolutionary consequences of fast fluctuations, we conducted nine independent experimental evolution experiments with bacteria. Experimental conditions were same for all species, and we allowed them to evolve either in fluctuating temperature alternating rapidly between 20°C and 40°C or at constant 30°C temperature. After experimental evolution, we tested the performance of the clones in both rapid fluctuation and in constant environments (20°C, 30°C and 40°C). Results from experiments on these nine species were combined meta-analytically. We found that overall the clones evolved in the fluctuating environment had evolved better efficiency in tolerating fluctuations (i.e., they had higher yield in fluctuating conditions) than the clones evolved in the constant environment. However, we did not find any evidence that fluctuation-adapted clones would have evolved better tolerance to any measured constant environments (20°C, 30°C, and 40°C). Our results back up recent empirical findings reporting that it is hard to predict adaptations to fast fluctuations using tolerance curves.Peer reviewe

    Intersubjectivity in action : An introduction

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    Intersubjectivity is a complex concept, and some central approaches to it have been discussed in areas of, for example, philosophy (based on e.g. early work by Schuetz 1953), developmental psychology (Trevarthen & Aitken 2001), neuroscience (Iacoboni 2008) and primatology (Tomasello 2008; Tomasello, Carpenter & Hobson 2005). In the realm of the interactional approach that the chapters in this volume represent we can initially note the following. Intersubjectivity is a precondition for all human life: for social organization as well as for individual development and well-being. A primordial site for its creation and maintenance is human interaction. By focusing on the creation and maintenance of intersubjectivity, the authors of this book approach the topic from the perspectives of turn and action design, action attribution, challenges in achieving shared understanding, embodied practices in meaning-making and synchronized participant conduct, as well as developmental aspects of intersubjectivity. The core theoretical and methodological framework is Conversation Analysis, combined with methods of interactional linguistics and multimodal interaction analysis as well as the study of gesture and psychophysiology. This research promotes an understanding that intersubjectivity involves joint understanding and sharing of experience between humans (see e.g. Linell 2017). Intersubjectivity in interaction requires referential common ground, shared understanding of the meaning of linguistic forms, shared understanding of actions and sequences of action and shared understanding of the expression of emotion in sequences of action.Non peer reviewe

    Diclofenac Does Not Reduce the Risk of Post-endoscopic Retrograde Cholangiopancreatography Pancreatitis in Low-Risk Units

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    Background Nonsteroidal anti-inflammatory drugs have an inhibitory role in pathogenesis of pancreatitis. Guidelines from the European Society of Gastrointestinal Endoscopy recommend routine rectal administration of 100 mg of diclofenac or indomethacin immediately before or after ERCP for all patients without contraindications. Aims Our aim was to evaluate the effect of diclofenac in preventing post-ERCP pancreatitis (PEP) in a high-volume, low-PEP-risk ERCP unit. Methods The rate and severity of PEP were compared in groups of 1000 historical controls prior to the routine use of diclofenac and in 1000 patients receiving 100 mg diclofenac before ERCP. Results PEP occurred in 56 (2.8%) of the 2000 patients, and the rate of the pancreatitis was 2.8% in control group and 2.8% in diclofenac group (p = 1.000). The PEP rate among the native papilla patients was 3.9% in control group and 3.6% in diclofenac group (p = 0.803). In subgroup analysis of patients with a high risk of PEP, diclofenac neither prevented PEP nor made its course milder. Conclusions In an unselected patient population in a center with a low incidence of PEP, diclofenac seems to have no beneficial effect.Peer reviewe

    Endoscopic therapy of sporadic non-ampullary duodenal adenomas, single centre retrospective analysis

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    Introduction Although sporadic non-ampullary duodenal adenomas (SNADA) are rare, with the risk of progression to cancer, they deserve therapy. Endoscopic therapy of SNADA is effective, but with the increased risk of complications, endotherapy should be performed in high-volume units. The results of endotherapy of SNADA in our unit are presented. Patients and methods A total of 97 patients with SNADA had endoscopic resection in 2005-2021 and control endoscopies between 3 and 24 months. Snare polypectomy, endoscopic mucosal resection (EMR), endoscopic band ligation (EBL) and endoloop were used (en bloc 37% and piecemeal 63%). In cases of residual/recurrent adenomas, endotherapy was repeated. Results The median size of the adenoma was 12 (5-60) mm and most polyps were sessile (25%) or flat (65%). Primary endotherapy eradicated adenomas in 57 (59%) cases. Residual and recurrence rates were 24% (n = 23) and 17% (n = 16) with successful endotherapy in 16 (70%) and 13 (81%) patients. Endotherapy was successful in 86 (89%) patients after a median (range) follow-up of 23 (1-166) months. Four out of 11 patients with failed endotherapy had surgery; seven patients were not fit for surgery. There were no disease-specific deaths or carcinoma. Eleven patients (11%) suffered from complications: perforation requiring surgery (n = 1), sepsis (n = 1), postprocedure bleeding (n = 7), cardiac arrest (n = 1) and coronary infarct (n = 1). The thirty-day mortality was zero. Colonoscopy was performed on 67 (69%) patients with neoplastic lesions in 33% patients during follow-up. Conclusions Endotherapy of SNADA is effective and safe. Repeat endotherapy in residual and recurrent adenomas is successful. Careful patient selection is mandatory.Peer reviewe

    Assessment of sedation level for endoscopic retrograde cholangiopancreatography - a prospective validation study

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    Background and aims: There is no consensus on how to assess the depth of sedation for endoscopic retrograde cholangiopancreatography (ERCP). This study was carried out in order to evaluate different methods of assessment of depth of sedation: bispectral index (BiS), modified Richmond Agitation/Sedation Scale (mRASS), modified Ramsay Sedation Scale (mRSS) and modified Observer Assessment of Alertness and Sedation (mOAAS) and their applicability to clinical practice.Methods: Two hundred patients were recruited. Sedation was given by standard clinical practice using propofol sedation or patient controlled sedation. Sedation was assessed on all patients using the above-mentioned methods. BiS was considered the reference point for sedation scales. Cronbach's alpha was calculated to determine the consistency of different scales in respect to each other and prediction probability and Spearman's correlation coefficients of sedation scales were calculated to show the relationship between sedation scales and BiS.Results: All scales showed high reliability with overall Cronbach's alpha 0.943. Dropping scales suggested better consistency between mOAAS, mRSS and mRASS than with BiS. Spearman's correlation and prediction probability showed similar results with all tested scales: mOAAS (0.695, 0.739), mRSS (0.673, 0.735), mRASS (0.683, 0.738), pPeer reviewe

    Benign biliary strictures treated with biodegradable stents in patients with surgically altered anatomy using double balloon enteroscopy

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    Objectives Surgically altered anatomy complicates endoscopical procedures of pancreatobiliary tree. Biliary or hepaticojejunal anastomosis strictures have been managed using percutaneous transhepatic or double balloon enteroscopy (DBE) techniques with multiple plastic stents, or fully covered self-expandable metal stents. We report the first seven cases with surgically altered anatomy treated with biodegradable stents with DBE. Materials and methods Seven cases with altered anatomy, all with Roux-en-Y hepaticojejunostomy (HJ), were treated for HJ anastomosis strictures (3 cases) and intrahepatic biliary stricture (4 cases). Fujifilm DB enteroscope with a 200 cm long and 3.2 mm wide working channel was used. Balloon dilatations were first performed and then 1-3 biodegradable stents were deployed with a pusher over a guidewire. Results Two patients had HJ due to liver resections, one due to biliary injury in cholecystectomy and four due to liver transplantation because of primary sclerosing cholangitis (PSC). Median duration of the procedures was 56 min. Deployment of the stents took less than 20 min per patient. There were no stent or cholangiography related adverse events, but one patient required endotracheal intubation for nose bleeding caused by the placement of nasopharyngeal tube. Two PSC patients had recurrent cholangitis in the follow up. There was one stent migration in 90 day follow up. With all the HJ anastomotic strictures resolution of strictures seemed to be achieved. Conclusions Treatment of biliary or anastomosis strictures in altered anatomy is complex and time consuming. The biodegradable stent, which can be passed through working channel of a long enteroscope, seems promising in the treatment of these strictures. The benefit is that no stent removal is needed.Peer reviewe

    Repeated Negative Urine Trypsinogen-2 Dipstick Test Rules Out Diagnosis of Post-ERCP Pancreatitis

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    Background: A dipstick test for urine trypsinogen-2 has been used in the diagnosis of acute pancreatitis, but there are only a few studies exploring the effectiveness of this test for early diagnose of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). Goals: The authors explore if the rapid point-of-care urine trypsinogen-2 dipstick test can replace assay of amylase in diagnosing PEP. Study: For this prospective study, from Helsinki University Hospital 400 ERCP patients were enrolled in whom the authors analyzed plasma amylase or pancreas-specific amylase, bilirubin, and urine trypsinogen-2, and urine trypsinogen-2 with dipstick before, 4 and 24 hours after ERCP. Results: PEP developed in 15 (3.8%) patients. Urine trypsinogen-2 concentrations were significantly higher in PEP than in non-PEP patients 24 hours after ERCP (P=0.001, Mann-Whitney U test) but not 4 hours after ERCP (P=0.094). When combined with abdominal pain symptoms at 4 hours the dipstick test had a sensitivity of 60%, a specificity of 99%, a positive predictive value of 64%, and a negative predictive value 98%. At 24 hours, sensitivity was 100%, specificity 98%, positive predictive value 71%, and negative predictive value 100%. Conclusions: A positive dipstick seems to identify PEP cases and a negative test excludes PEP with high accuracy.Peer reviewe

    An immunocapture-LC-MS-based assay for serum SPINK1 allows simultaneous quantification and detection of SPINK1 variants

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    Pancreatic secretory trypsin inhibitor Kazal type 1 (SPINK1) is a 6420 Da peptide produced by the pancreas, but also by several other tissues and many tumors. Some mutations of the SPINK1 gene, like the one causing amino acid change N34S, have been shown to confer susceptibility to recurrent or chronic pancreatitis. Detection of such variants are therefore of clinical utility. So far SPINK1 variants have been determined by DNA techniques. We have developed and validated an immunocapture-liquid chromatography-mass spectrometric (IC-LC-MS) assay for the detection and quantification of serum SPINK1, N34S-SPINK1, and P55S-SPINK1. We compared this method with a time-resolved immunofluorometric assay (TR-IFMA) for serum samples and primer extension analysis of DNA samples. We used serum and DNA samples from patients with acute pancreatitis, renal cell carcinoma, or benign urological conditions. With the help of a zygosity score calculated from the respective peak areas using the formula wild-type (wt) SPINK1/(variant SPINK1 + wt SPINK1), we were able to correctly characterize the heterozygotes and homozygotes from the samples with DNA information. The score was then used to characterize the apparent zygosity of the samples with no DNA characterization. The IC-LC-MS method for SPINK1 was linear over the concentration range 0.5-1000 mu g/L. The limit of quantitation (LOQ) was 0.5 mu g/L. The IC-LC-MS and the TR-IFMA assays showed good correlation. The median zygosity score was 1.00 (95% CI 0.98-1.01, n = 11), 0.55 (95% CI 0.43-0.61, n = 14), and 0.05 (range 0.04-0.07, n = 3) for individuals found to be wt, heterozygous, and homozygous, respectively, for the N34S-SPINK1 variant by DNA analysis. When DNA samples are not available, this assay facilitates identification of the N34S- and P55S-SPINK1 variants also in archival serum samples.Peer reviewe
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