326 research outputs found

    Small and Medium Amplitude Oscillatory Shear Rheology of Model Branched Polystyrene (PS) Melts

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    Linear and nonlinear rheological properties of model comb polystyrenes (PS) with loosely to densely grafted architectures were measured under small and medium amplitude oscillatory shear (SAOS and MAOS) flow. This comb PS set had the same length of backbone and branches but varied in the number of branches from 3 to 120 branches. Linear viscoelastic properties of the comb PS were compared with the hierarchical model predictions. The model underpredicted zero-shear viscosity and backbone plateau modulus of densely branched comb with 60 or 120 branches because the model does not include the effect of side chain crowding. First- and third-harmonic nonlinearities reflected the hierarchy in the relaxation motion of comb structures. Notably, the low-frequency plateau values of first-harmonic MAOS moduli scaled with M2^{-2}w_{w} (total molecular weight), reflecting dynamic tube dilution (DTD) by relaxed branches. Relative intrinsic nonlinearity Q0_{0} exhibited the difference between comb and bottlebrush via no low-frequency Q0_{0} peak of bottlebrush corresponding to backbone relaxation, which is probably related to the stretched backbone conformation in bottlebrush

    Remineralization Property of an Orthodontic Primer Containing a Bioactive Glass with Silver and Zinc

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    White spot lesions (WSLs) are irreversible damages in orthodontic treatment due to excessive etching or demineralization by microorganisms. In this study, we conducted a mechanical and cell viability test to examine the antibacterial properties of 0.2% and 1% bioactive glass (BAG) and silver-doped and zinc-doped BAGs in a primer and evaluated their clinical applicability to prevent WSLs. The microhardness statistically significantly increased in the adhesive-containing BAG, while the other samples showed no statistically significant difference compared with the control group. The shear bond strength of all samples increased compared with that of the control group. The cell viability of the control and sample groups was similar within 24 h, but decreased slightly over 48 h. All samples showed antibacterial properties. Regarding remineralization property, the group containing 0.2% of the samples showed remineralization properties compared with the control group, but was not statistically significant; further, the group containing 1% of the samples showed a significant difference compared with the control group. Among them, the orthodontic bonding primer containing 1% silver-doped BAG showed the highest remineralization property. The new orthodontic bonding primer used in this study showed an antimicrobial effect, chemical remineralization effect, and WSL prevention as well as clinically applicable properties, both physically and biologically

    A current drive by using the fast wave in frequency range higher than two timeslower hybrid resonance frequency on tokamaks

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    An efficient current drive scheme in central or off-axis region is required for the steady state operation of tokamak fusion reactors. The current drive by using the fast wave in frequency range higher than two times lower hybrid resonance (w>2wlh) could be such a scheme in high density, high temperature reactor-grade tokamak plasmas. First, it has relatively higher parallel electric field to the magnetic field favorable to the current generation, compared to fast waves in other frequency range. Second, it can deeply penetrate into high density plasmas compared to the slow wave in the same frequency range. Third, parasitic coupling to the slow wave can contribute also to the current drive avoiding parametric instability, thermal mode conversion and ion heating occured in the frequency range w<2wlh. In this study, the propagation boundary, accessibility, and the energy flow of the fast wave are given via cold dispersion relation and group velocity. The power absorption and current drive efficiency are discussed qualitatively through the hot dispersion relation and the polarization. Finally, those characteristics are confirmed with ray tracing code GENRAY for the KSTAR plasmas

    Urachal Actinomycosis Mimicking a Urachal Tumor

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    A 26-year-old man presented with lower abdominal discomfort and a palpable mass in the right lower quadrant. An abdominal computed tomography (CT) scan revealed an abdominal wall mass that extended from the dome of the bladder. Fluorine-18 fluorodeoxyglucose (FDG) positron-emission tomography/CT (PET/CT) showed hypermetabolic wall thickening around the bladder dome area that extended to the abdominal wall and hypermetabolic mesenteric infiltration. Differential diagnosis included a urachal tumor with invasion into adjacent organs and chronic inflammatory disease. Partial cystectomy with abdominal wall mass excision was performed, and the final pathologic report was consistent with urachal actinomycosis

    Influence of anesthesia methods on surgical outcomes and renal function in retrograde intrarenal stone surgery: a prospective, randomized controlled study

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    Background We analyzed the influence of anesthesia methods on surgical outcomes and renal function in retrograde intrarenal surgery (RIRS) in a prospective, randomized controlled study. Methods Seventy patients who underwent RIRS from September 2015 to February 2017 were randomly allocated to general anesthesia (GA) or spinal anesthesia (SA) groups. Renal function was assessed using estimated glomerular filtration rate, and separate renal function was evaluated using nuclear medicine tests. Maneuverability and accessibility were evaluated after every surgery. All procedures were performed by a single experienced surgeon (SY Cho). Results Stone-free rate was higher in the GA (92.3%, 36 of 39) than the SA (71.0%, 22 of 31) (P = 0.019) group. Pain score was higher in the GA than in the SA group on the first postoperative morning (P = 0.025), but pain scores of the two groups were similar before discharge (P = 0.560). There were no differences in the changes of serum creatinine level (P = 0.792) and changes of estimated glomerular filtration rate (P = 0.807). Differences of separate renal function between operative and contralateral site increased significantly in patients under GA than under SA at postoperative 3 months (P = 0.014). Maneuverability and accessibility were better in SA with sedation than GA (P < 0.001). Conclusions RIRS under SA showed advantages in renal function change using renogram at postoperative 3 months and in lower pain score on the first postoperative morning. Performance of operator under SA was worse than that under GA and significantly improved with sedation. RIRS under SA showed advantages in lower pain score at postoperative first day. Trial registration Clinicaltrials.gov ID is NCT03957109, and registration date is 17th May 2019. This study was retrospectively registered.This study was supported by grant no. 04–2015-0680 from the SNUH Research Fund

    Reversible Pulmonary Hypertension in Adolescent with Left Atrial Myxoma

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    We report a patient of left atrial huge myxoma presenting with severe pulmonary hypertension in adolescents. A patient was a 14-year-old boy presented with sudden onset dyspnea. Transthoracic echocardiographic study revealed the presence of a nodular, 4.34 × 8.11 cm sized, mobile, hyperechoic mass in the left atrium and severe pulmonary hypertension with tricuspid insufficiency. After surgical therapy, tricuspid regurgitation and pulmonary hypertension was decreased and the patient was stabilized and had an uneventful clinical course

    Long-term survival benefits of intrathecal autologous bone marrow-derived mesenchymal stem cells (Neuronata-R®: lenzumestrocel) treatment in ALS: Propensity-score-matched control, surveillance study

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    ObjectiveNeuronata-R® (lenzumestrocel) is an autologous bone marrow-derived mesenchymal stem cell (BM-MSC) product, which was conditionally approved by the Korean Ministry of Food and Drug Safety (KMFDS, Republic of Korea) in 2013 for the treatment of amyotrophic lateral sclerosis (ALS). In the present study, we aimed to investigate the long-term survival benefits of treatment with intrathecal lenzumestrocel.MethodsA total of 157 participants who received lenzumestrocel and whose symptom duration was less than 2 years were included in the analysis (BM-MSC group). The survival data of placebo participants from the Pooled-Resource Open-Access ALS Clinical Trials (PROACT) database were used as the external control, and propensity score matching (PSM) was used to reduce confounding biases in baseline characteristics. Adverse events were recorded during the entire follow-up period after the first treatment.ResultsSurvival probability was significantly higher in the BM-MSC group compared to the external control group from the PROACT database (log-rank, p &lt; 0.001). Multivariate Cox proportional hazard analysis showed a significantly lower hazard ratio for death in the BM-MSC group and indicated that multiple injections were more effective. Additionally, there were no serious adverse drug reactions found during the safety assessment, lasting a year after the first administration.ConclusionThe results of the present study showed that lenzumestrocel treatment had a long-term survival benefit in real-world ALS patients

    Endoscopic Pancreatic Sphincterotomy: Indications and Complications

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    Background/Aims: Although a few recent studies have reported the effectiveness of endoscopic pancreatic sphincterotomy (EPST), none has compared physicians' skills and complications resulting from the procedure. Thus, we examined the indications, complications, and safety of EPST performed by a single physician at a single center. Methods: Among 2,313 patients who underwent endoscopic retrograde cholangiopancreatography between January 1996 and March 2008, 46 patients who underwent EPST were included in this retrospective study. We examined the indications, complications, safety, and effectiveness of EPST, as well as the need for a pancreatic drainage procedure and the concomitant application of EPST and endoscopic sphincterotomy (EST). Results: Diagnostic indications for EPST were chronic pancreatitis (26 cases), pancreatic divisum (4 cases), and pancreatic cancer (8 cases). Therapeutic indications for EPST were removal of a pancreaticolith (10 cases), stent insertion for pancreatic duct stenosis (9 cases), nasopancreatic drainage (7 cases), and treatment of sphincter of Oddi dysfunction (1 case). The success rate of EPST was 95.7% (44/46). Acute complications of EPST included five cases (10.9%) of pancreatitis and one of cholangitis (2.2%). EPST with EST did not reduce biliary complications. Endoscopic pancreatic drainage procedures following EPST did not reduce pancreatic complications. Conclusions: EPST showed a low incidence of complications and a high rate of treatment success; thus, EPST is a relatively safe procedure that can be used to treat pancreatic diseases. Pancreatic drainage procedures and additional EST following EPST did not reduce the incidence of procedure-related complications

    Comparison of the Efficacy of Glimepiride, Metformin, and Rosiglitazone Monotherapy in Korean Drug-Naïve Type 2 Diabetic Patients: The Practical Evidence of Antidiabetic Monotherapy Study

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    BackgroundAlthough many anti-diabetic drugs have been used to control hyperglycemia for decades, the efficacy of commonly-used oral glucose-lowering agents in Korean type 2 diabetic patients has yet to be clearly demonstrated.MethodsWe evaluated the efficacy of glimepiride, metformin, and rosiglitazone as initial treatment for drug-naïve type 2 diabetes mellitus patients in a 48-week, double-blind, randomized controlled study that included 349 Korean patients. Our primary goal was to determine the change in HbA1c levels from baseline to end point. Our secondary goal was to evaluate changes in fasting plasma glucose (FPG) levels, body weight, frequency of adverse events, and the proportion of participants achieving target HbA1c levels.ResultsHbA1c levels decreased from 7.8% to 6.9% in the glimepiride group (P<0.001), from 7.9% to 7.0% in the metformin group (P<0.001), and from 7.8% to 7.0% (P<0.001) in the rosiglitazone group. Glimepiride and rosiglitazone significantly increased body weight and metformin reduced body weight during the study period. Symptomatic hypoglycemia was more frequent in the glimepiride group and diarrhea was more frequent in the metformin group.ConclusionThe efficacy of glimepiride, metformin, and rosiglitazone as antidiabetic monotherapies in drug-naïve Korean type 2 diabetic patients was similar in the three groups, with no statistical difference. This study is the first randomized controlled trial to evaluate the efficacy of commonly-used oral hypoglycemic agents in Korean type 2 diabetic patients. An additional subgroup analysis is recommended to obtain more detailed information

    Efficacy and Safety of Enavogliflozin versus Dapagliflozin as Add-on to Metformin in Patients with Type 2 Diabetes Mellitus: A 24-Week, Double-Blind, Randomized Trial

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    Background Enavogliflozin is a novel sodium-glucose cotransporter-2 inhibitor currently under clinical development. This study evaluated the efficacy and safety of enavogliflozin as an add-on to metformin in Korean patients with type 2 diabetes mellitus (T2DM) against dapagliflozin. Methods In this multicenter, double-blind, randomized, phase 3 study, 200 patients were randomized to receive enavogliflozin 0.3 mg/day (n=101) or dapagliflozin 10 mg/day (n=99) in addition to ongoing metformin therapy for 24 weeks. The primary objective of the study was to prove the non-inferiority of enavogliflozin to dapagliflozin in glycosylated hemoglobin (HbA1c) change at week 24 (non-inferiority margin of 0.35%) (Clinical trial registration number: NCT04634500). Results Adjusted mean change of HbA1c at week 24 was –0.80% with enavogliflozin and –0.75% with dapagliflozin (difference, –0.04%; 95% confidence interval, –0.21% to 0.12%). Percentages of patients achieving HbA1c <7.0% were 61% and 62%, respectively. Adjusted mean change of fasting plasma glucose at week 24 was –32.53 and –29.14 mg/dL. An increase in urine glucose-creatinine ratio (60.48 vs. 44.94, P<0.0001) and decrease in homeostasis model assessment of insulin resistance (–1.85 vs. –1.31, P=0.0041) were significantly greater with enavogliflozin than dapagliflozin at week 24. Beneficial effects of enavogliflozin on body weight (–3.77 kg vs. –3.58 kg) and blood pressure (systolic/diastolic, –5.93/–5.41 mm Hg vs. –6.57/–4.26 mm Hg) were comparable with those of dapagliflozin, and both drugs were safe and well-tolerated. Conclusion Enavogliflozin added to metformin significantly improved glycemic control in patients with T2DM and was non-inferior to dapagliflozin 10 mg, suggesting enavogliflozin as a viable treatment option for patients with inadequate glycemic control on metformin alone
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