Artículos de revistas: "MMA"

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Kang, Dae-Soo y Seung-Gag Lim. "The Performance Comparison of MMA and S-MMA Adaptive Equalization Algorithm for QAM Signal". Journal of the Institute of Webcasting, Internet and Telecommunication 13, n.º 1 (28 de febrero de 2013): 19–26. http://dx.doi.org/10.7236/jiibc.2013.13.1.19.

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Lim, Seung-Gag. "FC-MMA Adaptive Equalization Algorithm to improve the Convergence Speed of MMA in 16-QAM System". Journal of the Institute of Webcasting, Internet and Telecommunication 14, n.º 1 (28 de febrero de 2014): 93–99. http://dx.doi.org/10.7236/jiibc.2014.14.1.93.

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Lim, Seung Gag. "Performance Comparison of SE-MMA and QE-MMA for Adaptive Equalization in Nonconstant modulus signal". Journal of the Institute of Internet Broadcasting and Communication 17, n.º 2 (30 de abril de 2017): 105–11. http://dx.doi.org/10.7236/jiibc.2017.17.2.105.

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Zhang, Heng, Ming Duan, Shenwen Fang, Lei Zhai y Xiujun Wang. "Preparation of a novel flocculant and its performance for treating acidic oily wastewater". RSC Advances 6, n.º 108 (2016): 106102–8. http://dx.doi.org/10.1039/c6ra20561e.

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In this study, a series of copolymers of methyl methacrylate (MMA), methacrylic acid (MAA) and chitosan (CS), named P(MMA–MAA–CS), were prepared via emulsion copolymerization (CS content in monomer mass was less than 3 wt%).

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Liu, Guoqin, Guojin Yan, Wenjun Zou y Zhengxin Li. "Investigation of Complexation of Linear Poly(N-vinyl-2-pyrrolidone) with Poly(methacrylic acid-co-methyl methacrylate) Gel". E-Journal of Chemistry 8, s1 (2011): S481—S487. http://dx.doi.org/10.1155/2011/151607.

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The contraction of poly(methacrylic acid-co-methyl methacrylate) (P(MAA-co-MMA)) gel induced by complexation with linear poly(N-vinyl-2-pyrrolidone) (PVP) is quite different from that of poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) gel. It was found that the concentration of PVP has a strong effect on the complexation with P(MAA-co-MMA) gel. When PVP was introduced into the P(MAA-co-MMA) network, its dynamic mechanic properties vary greatly between complexed and uncomplexed networks. It had the following results: (1) the higher modulus ratio; (2) a slight contraction of gel.

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Mączka, Eryk. "Badanie MMA". BUILDER 258, n.º 1 (1 de enero de 2019): 68–70. http://dx.doi.org/10.5604/01.3001.0013.3327.

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TEST OF MINERAL ASPHALT MIXTURES IN THE STATIC FOUR POINTBENDING TEST AT TEMPERATURE 25°C The article presents an experimental method for testing beams made of AC16W mineralasphalt mix in a static four-point bending test. Tests were performed at a fixed measuring temperature of 25°C and for different load levels. The conditions of the study that specify the variable characteristics of asphalt mixtures were specified. Attention was paid to the material specificity of the mixturesand the variability of the stiffness modulus was analyzed. Different ways of its determination with different load cycles are presented. The obtained results of the modules were compared with the results obtained in the dynamic test. The identification of the secant modulus from the dependence of the load curve between strain and stress for the first cycle was indicated.

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Hakim, Mohammad Lutful, Mohammad Tariqul Islam, Touhidul Alam, Sharul Kamal Abdul Abdul Rahim, Badariah Bais, Md Shabiul Islam y Mohamed S. Soliman. "Triple-Band Square Split-Ring Resonator Metamaterial Absorber Design with High Effective Medium Ratio for 5G Sub-6 GHz Applications". Nanomaterials 13, n.º 2 (4 de enero de 2023): 222. http://dx.doi.org/10.3390/nano13020222.

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This article proposes a square split-ring resonator (SSRR) metamaterial absorber (MMA) for sub-6 GHz application. The unit cell of the MMA was designed and fabricated on commercially available low-cost FR-4 substrate material with a dielectric constant o 4.3. The higher effective medium ratio (EMR) of the designed unit cell shows the compactness of the MMA. The dimension of the unit cell is 9.5 × 9.5 × 1.6 mm3, which consists of two split rings and two arms with outer SSRR. The proposed MMA operates at 2.5 GHz, 4.9 GHz, and 6 GHz frequency bands with a 90% absorption peak and shows a single negative metamaterial property. The E-field, H-field, and surface current are also explored in support of absorption analysis. Moreover, the equivalent circuit model of the proposed MMA is modelled and simulated to validate the resonance behavior of the MMA structure. Finally, the proposed MMA can be used for the specific frequency bands of 5G applications such as signal absorption, crowdsensing, SAR reduction, etc.

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López-Muñoz, R., M. E. Treviño, G. Morales, J. A. Valdez-Garza, R. Díaz de León, H. Saade, F. J. Enríquez-Medrano y R. G. López. "Ultrafine Nanoparticles of Poly(Methyl Methacrylate-co-Methacrylic Acid) Loaded with Aspirin". Journal of Nanomaterials 2019 (14 de agosto de 2019): 1–9. http://dx.doi.org/10.1155/2019/3059098.

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Nanoparticles of the poly(methyl methacrylate-co-methacrylic acid) or copolymer of P(MMA-co-MAA), were prepared by semicontinuous heterophase polymerization; they show a mean diameter of 12 nm and a 1.75 MMA/MAA molar ratio determined by carbon-13 nuclear magnetic resonance. The content of MAA, greater than that of Eudragit S100, copolymer of P(MMA-co-MAA) accepted by the FDA for the preparation of tablets, ensures its biocompatibility and its metabolism without toxic effects. Loaded with up to 22 wt. % aspirin, that is, acetylsalicylic acid (ASA), these nanoparticles increase slightly their size, according to transmission electron microscopy; however, the presence of ASA on the nanoparticle surface decreases their stability, which leads to a certain aggregation of the particles in the dispersion. Fourier transform infrared spectrometry was used for demonstrating the loading of ASA in the nanoparticles.

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Tran, Minh-Sang y Sheng-Jye Hwang. "Design and Simulation of Electromagnetic Linear Actuators for Jet Dispensers". Applied Sciences 10, n.º 5 (1 de marzo de 2020): 1653. http://dx.doi.org/10.3390/app10051653.

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Three electromagnetic-based linear actuators, namely a solenoid actuator (SA), a moving coil actuator (MCA), and a moving magnet actuator (MMA), are proposed for driving the needle in a jet dispenser. The total resistance force acting on the needle during operation, including the damping force, the friction force, the inertia force, the compression spring force, and the backpressure, are measured by an experimental model. The thrust force required to overcome this resistance force is then predicted for each actuator using finite element analysis (FEA) simulations. Simple two-dimensional models of the SA, MCA, and MMA are constructed using the same coil dimensions in every case in order to facilitate an objective comparison between them. Simulations in ANSYS Maxwell software are then performed to adjust the specific dimensions of each actuator structure in such a way as to generate the thrust force required to drive the needle in the jet dispenser with the minimum excitation current possible. The simulation results show that for a maximum needle driving frequency of 250 Hz and a stroke length of 0.5 mm, the excitation current required to generate the necessary thrust force is equal to 1.8 A and 1.9 A for the MCA and MMA models, respectively, when a return spring is not used, and 2.2 A, 3.8 A, and 4.1 A for the SA, MCA, and MMA models, respectively, when a return spring is employed. It is additionally shown that the thrust force drop of the MCA and MMA models is far less than that of the SA model, about 0.7%, 1.8%, and 61% for three models, respectively. Three preliminary designs for jet dispensers incorporating the proposed actuators are also generated for reference purposes.

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Maines, Evelina, Roberto Franceschi, Francesca Rivieri, Giovanni Piccoli, Björn Schulte, Jessica Hoffmann, Andrea Bordugo et al. "Biochemical Pattern of Methylmalonyl-CoA Epimerase Deficiency Identified in Newborn Screening: A Case Report". International Journal of Neonatal Screening 10, n.º 3 (18 de julio de 2024): 53. http://dx.doi.org/10.3390/ijns10030053.

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Methylmalonyl-CoA epimerase enzyme (MCEE) is responsible for catalyzing the isomeric conversion between D- and L-methylmalonyl-CoA, an intermediate along the conversion of propionyl-CoA to succinyl-CoA. A dedicated test for MCEE deficiency is not included in the newborn screening (NBS) panels but it can be incidentally identified when investigating methylmalonic acidemia and propionic acidemia. Here, we report for the first time the biochemical description of a case detected by NBS. The NBS results showed increased levels of propionylcarnitine (C3) and 2-methylcitric acid (MCA), while methylmalonic acid (MMA) and homocysteine (Hcy) were within the reference limits. Confirmatory analyses revealed altered levels of metabolites, including MCA and MMA, suggesting a block in the propionate degradation pathway. The analysis of methylmalonic pathway genes by next-generation sequencing (NGS) allowed the identification of the known homozygous nonsense variation c.139C>T (p.R47X) in exon 2 of the MCE gene. Conclusions: Elevated concentrations of C3 with a slight increase in MCA and normal MMA and Hcy during NBS should prompt the consideration of MCEE deficiency in differential diagnosis. Increased MMA levels may be negligible at NBS as they may reach relevant values beyond the first days of life and thus could be identified only in confirmatory analyses.

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Al-Dirbashi, Osama Y., Charu Sharma, Nahid Al Dahouri, Anas Al Aidaros, Shamma Al-Muhairi, Rami Beiram, Salah Gariballa y Juma Al Kaabi. "Role of Functional Biomarkers to Identify Early Vitamin B12 Deficiency in Patients with Sleeve Gastrectomy: A Cross-Sectional Study". Medicina 56, n.º 3 (20 de marzo de 2020): 142. http://dx.doi.org/10.3390/medicina56030142.

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Background and objectives: Although laparoscopic sleeve gastrectomy (LSG) is effective for obesity management, postoperative vitamin B12 (B12) deficiency is of major concern. In this cross-sectional study, we assessed the levels of B12 and its related functional biomarkers, namely, total homocysteine (tHcy), methylmalonic acid (MMA), folate, methylcitric acid (MCA), and hemoglobin (Hb), in one-year postoperative LSG patients and matched controls. Materials and Methods: Plasma B12, tHcy, MMA, folate, and MCA were measured in matched controls (n = 66) and patients (n = 71) using validated liquid chromatography-tandem mass spectrometry techniques and protocols in the United Arab Emirates (UAE). Results: The median B12 concentration in patients (177 pmol/L) was significantly lower (p < 0.001) than in the controls (334.7 pmol/L). The tHcy and MMA levels were significantly increased (p < 0.001 and p = 0.011, respectively) and folate levels were significantly decreased (p = 0.001) in the LSG patients compared to the controls. Interestingly, no significant difference in MCA levels were observed between the two groups. The levels of tHcy and MMA were concomitantly increased with the decreased folate levels in postoperative LSG patients when compared with the controls. The Hb levels were significantly lower in males and females in the patient group compared with those in the control group, respectively (p = 0.005 and p = 0.043). Conclusions: This is the first report of serum levels of B12 and its functional biomarkers in postoperative LSG patients among a local population from the UAE. Our findings revealed significant alterations of the B12 biomarkers, total B12, MMA, and tHcy in one-year postoperative LSG patients.

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Lv, Sheng Hua y Di Li. "Preparation and Properties of Tetrabasic Graft Copolymer Adhesive of CR/TPI/MMA/MAA". Applied Mechanics and Materials 80-81 (julio de 2011): 400–404. http://dx.doi.org/10.4028/www.scientific.net/amm.80-81.400.

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The chloroprene rubber (CR) and trans isoprene rubber (TPI) combined with methyl methacrylate (MMA) and α-Methylacrylic acid (MAA) to obtain a tetrabasic graft copolymer adhesive in a low poisonous mixing solvent. The effect of solvent, ratio of CR and TPI, benzoyl peroxide (BPO) amount, the dosage of MMA and MAA on the adhesive properties was investigated by studied the relationship between graft percentage (GP) and the T peel strength (T-PS) of various graft copolymer adhesives. The results showed that an excellent tetrabasic graft copolymer adhesive was obtained by a copolymerization of CR, TPI, MMA and MAA was 85 g, 15 g, 0.8 g, 60 g and 10 g using 0.8g BPO as initiator in a low poisnouos mixing solvent consisted of 124 g ethyl acetate (EA), 44 g pyroacetic spirit (PK) and 32 g toluene (TOL) at 85 °C for 5 h. The chemical structure of the tetrabasic graft copolymer adhesive was characterized by FTIR.

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Haas, Patrick, Monika Fudali, Sophie S. Wang, Helene Hurth, Till-Karsten Hauser, Ulrike Ernemann, Marcos Tatagiba, Nadia Khan y Constantin Roder. "Quality of life impairment in adult Moyamoya patients—preoperative neuropsychological assessment and correlation to MRI and H215O PET findings". Neurosurgical Review 45, n.º 2 (20 de octubre de 2021): 1533–41. http://dx.doi.org/10.1007/s10143-021-01660-9.

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AbstractMoyamoya angiopathy (MMA) related cerebral perfusion deficits or infarctions might influence quality of life (QoL). This study examines preoperative QoL in adult patients with MMA and correlates these with findings obtained via diagnostic imaging. Sixty-seven adult Moyamoya patients underwent preoperative neuropsychological testing including questionnaires to determine QoL, as well as psychiatric and depressive symptoms. The results were checked for correlation with territorial hypoperfusions seen in H215O PET with acetazolamide (ACZ) challenge (cerebrovascular reserve) and infarction patterns observed in MRI. Each vascular territory was analyzed separately and correlated with QoL. Physical role function was restricted in 41.0% of cases and emotional role function in 34.4% of cases (SF-36). Obsessive–compulsive disorder (39.3%) (SCL-90-R), psychoticism (34.4%) (SCL-90-R), and depression (32.7%) (BDI-II) were also very common. Psychoticism was significantly more frequent in cases where perfusion deficits in PET CT were observed in both MCA territories (left p = 0.0124, right p = 0.0145) and infarctions in MRI were present in the right MCA territory (p = 0.0232). Depression was significantly associated with infarctions in the right MCA territory (SCL-90-R p = 0.0174, BDI-II p = 0.0246). Women were affected more frequently by depression (BDI-II, p = 0.0234). Physical role function impairment was significantly associated with perfusion deficits in the left MCA territory (p = 0.0178) and infarctions in the right MCA territory (p = 0.0428). MMA leads to impairments in different areas of QoL. Approximately one-third of all adult MMA patients suffered from depression, with women being most affected. In addition to depression, presence of executive dysfunctions and mental disorders such as psychoticism, obsessive–compulsive disorder, and impaired physical and emotional role function affected QoL. These patients showed significantly more often infarctions and perfusion deficits in the right MCA territory. Long-term studies with follow-up results are necessary to clarify a possible beneficial impact of early surgical revascularization on QoL and depression in adult MMA patients.

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Li, Qiliang, Hong Jin, Ying Liu, Yu Rong, Tana Yang, Xiaolu Nie y Wenqi Song. "Determination of Cytokines and Oxidative Stress Biomarkers in Cognitive Impairment Induced by Methylmalonic Acidemia". Neuroimmunomodulation 28, n.º 3 (2021): 178–86. http://dx.doi.org/10.1159/000511590.

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Objective: Methylmalonic acidemia (MMA) is the most common organic acidemia in children. Many patients with MMA suffered from cognitive impairments. The aim of this study was to identify the significance of cytokines and oxidative stress biomarkers in MMA-induced cognitive impairment. Methods: We enrolled 64 children with combined MMA and homocystinuria and 64 age- and sex-matched healthy volunteers. Participants were subsequently classified as with or without cognitive impairments using a uniform neuropsychological assessment test. Serum samples were collected. The serum levels of cytokines and oxidative stress biomarkers were measured using the ELISA or chemical methods. Results: Compared to control group, the serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, malondialdehyde (MDA), and nitric oxide (NO) in the MMA patients increased markedly (p < 0.05); glutathione (GSH) and superoxide dismutase (SOD) decreased obviously (p < 0.01). The levels of IL-6, TNF-α, NO, and MDA in the serum were negatively associated with DQ or IQ scores. The levels of GSH and SOD in the serum were positively correlated with DQ or IQ scores. After receiver operating characteristic curve analysis, NO was the most useful individual marker for distinguishing the cognitive dysfunction, corresponding to the area under ROC curve (AUC) of 0.82 (95% CI, 0.74–0.91), sensitivity of 76.60%, and specificity of 80.25%. GSH and MDA were also useful for diagnosis of MMA-induced cognitive dysfunction, corresponding to the AUC of 0.80 (95% CI, 0.70–0.89), and 0.73 (95% CI, 0.63–0.82), respectively. The sensitivity and specificity of GSH were 72.34 and 80.25%, respectively. The sensitivity and specificity of MDA were 85.11 and 51.85%, respectively. Conclusions: The high-concentration methylmalonic acid in the blood induced immune cells to release pro-inflammatory cytokines such as TNF-α and IL-6. These cytokines and high-concentration methylmalonic acid stimulated the immune cells to produce reactive oxygen species (ROS) and reactive nitrogen species (RNS). The serum methylmalonic acid, cytokines, ROS, and RNS were across the blood-brain barrier and induced cognitive impairment. The small molecule substances such as serum NO, MDA, and GSH participated in the process of neuroinflammation and oxidative stress injury induced by MMA and could be useful for distinguishing the cognitive impairment.

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Loosen, Sven H., Vincent van den Bosch, Joao Gorgulho, Maximilian Schulze-Hagen, Jennis Kandler, Markus S. Jördens, Frank Tacke et al. "Progressive Sarcopenia Correlates with Poor Response and Outcome to Immune Checkpoint Inhibitor Therapy". Journal of Clinical Medicine 10, n.º 7 (25 de marzo de 2021): 1361. http://dx.doi.org/10.3390/jcm10071361.

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Background: Immune checkpoint inhibitors (ICIs) represent a new therapeutic standard for an increasing number of tumor entities. Nevertheless, individual response and outcome to ICI is very heterogeneous, and the identification of the ideal ICI candidate has remained one of the major issues. Sarcopenia and the progressive loss of muscle mass and strength, as well as muscular fat deposition, have been established as negative prognostic factors for a variety of diseases, but their role in the context of ICI therapy is not fully understood. Here, we have evaluated skeletal muscle composition as a novel prognostic marker in patients undergoing ICI therapy for solid malignancies. Methods: We analyzed patients with metastasized cancers receiving ICI therapy according to the recommendation of the specific tumor board. Routine CT scans before treatment initialization and during ICI therapy were used to assess the skeletal muscle index (L3SMI) as well as the mean skeletal muscle attenuation (MMA) in n = 88 patients receiving ICI therapy. Results: While baseline L3SMI and MMA values were unsuitable for predicting the individual response and outcome to ICI therapy, longitudinal changes of the L3SMI and MMA (∆L3SMI, ∆MMA) during ICI therapy turned out to be a relevant marker of therapy response and overall survival. Patients who responded to ICI therapy at three months had a significantly higher ∆L3SMI compared to non-responders (−3.20 mm2/cm vs. 1.73 mm2/cm, p = 0.002). Moreover, overall survival (OS) was significantly lower in patients who had a strongly decreasing ∆L3SMI (<−6.18 mm2/cm) or a strongly decreasing ∆MMA (<−0.4 mm2/cm) during the first three month of ICI therapy. Median OS was only 127 days in patients with a ∆L3SMI of below −6.18 mm2/cm, compared to 547 days in patients with only mildly decreasing or even increasing ∆L3SMI values (p < 0.001). Conclusion: Both progressive sarcopenia and an increasing skeletal muscle fat deposition are associated with poor response and outcome to ICI therapy, which might help to guide treatment decisions during ICI therapy.

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Turgeon, Coleman T., Mark J. Magera, Carla D. Cuthbert, Perry R. Loken, Dimitar K. Gavrilov, Silvia Tortorelli, Kimiyo M. Raymond, Devin Oglesbee, Piero Rinaldo y Dietrich Matern. "Determination of Total Homocysteine, Methylmalonic Acid, and 2-Methylcitric Acid in Dried Blood Spots by Tandem Mass Spectrometry". Clinical Chemistry 56, n.º 11 (1 de noviembre de 2010): 1686–95. http://dx.doi.org/10.1373/clinchem.2010.148957.

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BACKGROUND Newborn screening (NBS) for inborn errors of propionate, methionine, and cobalamin metabolism relies on finding abnormal concentrations of methionine and propionylcarnitine. These analytes are not specific for these conditions and lead to frequent false-positive results. More specific markers are total homocysteine (tHCY), methylmalonic acid (MMA), and methylcitric acid (MCA), but these markers are not detected by current NBS methods. To improve this situation, we developed a method for the detection of tHCY, MMA, and MCA in dried blood spots (DBSs) by liquid chromatography–tandem mass spectrometry (LC-MS/MS). METHODS The analytes were extracted from a single 4.8-mm DBS punch with acetonitrile:water:formic acid (59:41:0.42) containing dithiothreitol and isotopically labeled standards (d3-MMA, d3-MCA, d8-homocystine). The extract was dried and treated with 3 N HCl in n-butanol to form butylesters. After evaporation of the butanol, the residue was reconstituted and centrifuged and the supernatant was subjected to LC-MS/MS analysis. Algorithms were developed to apply this method as an efficient and effective second-tier assay on samples with abnormal results by primary screening. RESULTS The 99th percentiles determined from the analysis of 200 control DBSs for MMA, MCA, and HCY were 1.5, 0.5, and 9.8 μmol/L, respectively. Since 2005, prospective application of this second-tier analysis to 2.3% of all NBS samples led to the identification of 13 affected infants. CONCLUSIONS Application of this assay reduced the false-positive rate and improved the positive predictive value of NBS for conditions associated with abnormal propionylcarnitine and methionine concentrations.

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Teramoto, A., H. Shoji, H. Kura, Y. Sakakibara, T. Kamiya, K. Watanabe y T. Yamashita. "Investigation of factors related to the occurrence of osteochondral lesions of the talus by 3D bone morphology of the ankle". Bone & Joint Journal 100-B, n.º 11 (noviembre de 2018): 1487–90. http://dx.doi.org/10.1302/0301-620x.100b11.bjj-2018-0346.r1.

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Aims The aims of this study were to evaluate the morphology of the ankle in patients with an osteochondral lesion of the talus using 3D CT, and to investigate factors that predispose to this condition. Patients and Methods The study involved 19 patients (19 ankles) who underwent surgery for a medial osteochondral lesion (OLT group) and a control group of 19 healthy patients (19 ankles) without ankle pathology. The mean age was significantly lower in the OLT group than in the control group (27.0 vs 38.9 years; p = 0.02). There were 13 men and six women in each group. 3D CT models of the ankle were made based on Digital Imaging and Communications in Medicine (DICOM) data. The medial malleolar articular and tibial plafond surface, and the medial and lateral surface area of the trochlea of the talus were defined. The tibial axis-medial malleolus (TMM) angle, the medial malleolar surface area and volume (MMA and MMV) and the anterior opening angle of the talus were measured. Results The mean TMM angle was significantly larger in the OLT group (34.2°, sd 4.4°) than in the control group (29.2°, sd 4.8°; p = 0.002). The mean MMA and MMV were significantly smaller in the OLT group than in the control group (219.8 mm2, sd 42.4) vs (280.5 mm2, sd 38.2), and (2119.9 mm3, sd 562.5) vs (2646.4 mm3, sd 631.4; p < 0.01 and p = 0.01, respectively). The mean anterior opening angle of the talus was significantly larger in the OLT group than in the control group (15.4°, sd 3.9°) vs (10.2°, sd 3.6°; p < 0.001). Conclusion 3D CT measurements showed that, in patients with a medial osteochondral lesion of the talus, the medial malleolus opens distally, the MMA and MMV are small, and the anterior opening angle of the talus is large. This suggests that abnormal morphology of the ankle predisposes to the development of osteochondral lesions of the talus. Cite this article: Bone Joint J 2018;100-B:1487–90.

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Kasapgil, Esra, E. Gozde Atici, Ruhi Cicek, Ilke Anac y H. Yildirim Erbil. "Superhydrophobic polysiloxane filament growth on non-activated polymer coatings". RSC Advances 6, n.º 78 (2016): 74921–28. http://dx.doi.org/10.1039/c6ra11958a.

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Negim, El-Sayed, Nurlybayeva Aisha, Grigoriy A. Mun, Rinat Iskakov, Galiya S. Irmukhametova y Mussylmanbek Sakhy. "Preparation and Characterization of Acrylic Primer for Concrete Substrate Application". International Journal of Polymer Science 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/1754168.

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This study dealt with the properties of acrylic primer for concrete substrate using acrylic syrup, made from a methyl methacrylate monomer solution of terpolymers. Terpolymer systems consisting of methyl methacrylate (MMA), 2-ethylhexyl acrylate (2-EHA), and methacrylic acid (MAA) with different chemical composition ratios of MMA and 2-EHA were synthesized through bulk polymerization using azobisisobutyronitrile (AIBN) as initiator. The terpolymer composition is characterized by FTIR,1H NMR, DSC, TGA, and SEM. The glass transition temperature and the thermal stability increased with increasing amounts of MMA in the terpolymer backbone. The effect of chemical composition of terpolymers on physicomechanical properties of primer films was investigated. However, increasing the amount of MMA in terpolymer backbone increased tensile and contact angle of primer films while elongation at break, water absorption, and bond strength are decreased. In particular, the primer syrup containing 65% 2-EHA has good bonding strength with concrete substrate around 1.1 MPa.

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Darabi Mahboub, Mohammad Jaber, Mohammad Rostamizadeh, Jean-luc Dubois y Gregory S. Patience. "Partial oxidation of 2-methyl-1,3-propanediol to methacrylic acid: experimental and neural network modeling". RSC Advances 6, n.º 115 (2016): 114123–34. http://dx.doi.org/10.1039/c6ra16605a.

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Luo, Chunrong, Hong Tang y Xiaopeng Zhao. "Design and Preparation of a Kind Metal/p (MMA-MAA) ERF". International Journal of Modern Physics B 15, n.º 06n07 (20 de marzo de 2001): 672–77. http://dx.doi.org/10.1142/s0217979201005143.

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By the classical electrodynamics, the expression of interaction energy and force between two dipoles located arbitrary orientations are derived. Using direct polymerization method, we have prepared the metal/microcapsule-particles. Meanwhile an electrorheological fluid (ERF) made up by these composite particles is prepared. The ER behaviors were investigated by microscope and mechanical test, it is found that the very visible chain's structure of ERF can observe and the induced yield stress increased with the electric field and the particles' volume fraction.

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Chen, W. C., Y. Chuang y W. Y. Chiu. "Kinetics study of an acrylic tetrapolymer: Poly(IBMA-MMA-MAA-TBMA)". Journal of Applied Polymer Science 79, n.º 5 (2000): 853–63. http://dx.doi.org/10.1002/1097-4628(20010131)79:5<853::aid-app100>3.0.co;2-i.

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Pavlovic, Vojislav, Slobodanka Vakanjac, Milos Pavlovic y Nebojsa Pavlovic. "MMA syndrome in swine". Veterinarski glasnik 60, n.º 1-2 (2006): 81–87. http://dx.doi.org/10.2298/vetgl0602081p.

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The so-called swine civilization disease, also known as the MMA syndrome, implies good housing conditions and primarily a good diet. It occurs in highly productive swine breeds, and it does not occur in primitive breeds or in free-range swine production. Coprostasis which is present because of a subatantial diet occurs just before delivery of piglets. As a result of the altered conditions resulting from the appearance of coprostasis, the normal saprophytic microflora becomes pathogenic causing toxemia and bacteriemia which lead to puerperal diseases known as the metritis-mastitis-agalactia (MMA) syndrome. This disease is characterized by inflammation of the mammary gland (mastitis), the uterus (metritis), and reduced and suspended milk secretion (agalactia). The most recent data in literature indicate the complex etiology of this disease which involves infection with coliform bacteria, stress and hormonal disbalance.

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Tong, T. N., C. M. Cserti-Gazdewich y D. R. Branch. "Value of MMA crossmatch?" Transfusion Medicine 26, n.º 4 (4 de mayo de 2016): 301–2. http://dx.doi.org/10.1111/tme.12311.

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Fiedler, Miroslav. "Characterizations of MMA-matrices". Linear Algebra and its Applications 106 (agosto de 1988): 233–44. http://dx.doi.org/10.1016/0024-3795(88)90031-6.

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Dayananda, K., A. Ramakrishnan y R. Dhamodharan. "Synthesis and Characterization of Block Copolymers of P(MMA‐b‐n‐BA‐b‐MMA) via Ambient Temperature ATRP of MMA". Journal of Macromolecular Science, Part A 42, n.º 4 (13 de abril de 2005): 471–84. http://dx.doi.org/10.1081/ma-200054354.

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Jördens, Markus S., Linda Wittig, Lisa Heinrichs, Verena Keitel, Maximilian Schulze-Hagen, Gerald Antoch, Wolfram T. Knoefel et al. "Sarcopenia and Myosteatosis as Prognostic Markers in Patients with Advanced Cholangiocarcinoma Undergoing Palliative Treatment". Journal of Clinical Medicine 10, n.º 19 (23 de septiembre de 2021): 4340. http://dx.doi.org/10.3390/jcm10194340.

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Background: Cholangiocarcinoma (CCA) represents the second most common primary liver cancer and is characterized by a very poor outcome, but reliable prognostic markers are largely missing. Sarcopenia, the progressive loss of muscle mass and strength, as well as myosteatosis have been associated with an unfavorable outcome in several clinical conditions, including cancer. Here, we evaluated the prognostic relevance of sarcopenia and myosteatosis using routine abdominal CT (computed tomography) scans in advanced stage CCA patients undergoing palliative treatment. Methods: Routine abdominal CT scans were used to assess the skeletal muscle and the psoas muscle index (L3SMI/L3PMI) at the level of the third lumbar vertebra as radiological indices for sarcopenia as well as the mean skeletal muscle attenuation (MMA) as a surrogate for myosteatosis. Results were correlated with clinical data and outcomes. Results: Using a calculated optimal cut-off value of 71.95 mm2/cm, CCA patients with an L3SMI value below this cut-off showed a significantly reduced median overall survival (OS) of only 250 days compared to 450 days in patients with a higher L3SMI. Moreover, the median OS of CCA patients with an L3PMI above 6345 mm2/cm was 552 days compared to 252 days in patients with a lower L3PMI. Finally, CCA patients with an MMA above 30.51 Hounsfield Units survived significantly longer (median OS: 430 days) compared to patients with an MMA value below this ideal cut-off (median OS: 215 days). The prognostic relevance of L3SMI, L3PMI, and MMA was confirmed in uni- and multivariate Cox regression analyses. Conclusion: Routine abdominal CT scans represent a unique opportunity to evaluate sarcopenia as well as myosteatosis in advanced CCA patients. We identified the L3SMI/L3PMI as well as the MMA as negative prognostic factors in CCA patients undergoing palliative therapy, arguing that the “opportunistic” evaluation of these parameters might yield important clinical information in daily routine.

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Teramoto, Atsushi, Hiroaki Shoji, Hideji Kura, Yuzuru Sakakibara, Tomoaki Kamiya, Kota Watanabe y Toshihiko Yamashita. "Factors Related to the Occurrence of Osteochondral Lesions of the Talus by 3-dimensional Bone Morphology of the Ankle". Foot & Ankle Orthopaedics 3, n.º 3 (1 de julio de 2018): 2473011418S0048. http://dx.doi.org/10.1177/2473011418s00487.

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Category: Ankle Introduction/Purpose: Repeated microtrauma is thought to play a major role in the occurrence of osteochondral lesions of the talus (OLTs), but much remains unknown. Two-dimensional assessments of the relationship between ankle bone morphology and OLTs are occasionally seen. The purpose of this study was to evaluate the bone morphology of the ankle in OLT 3-dimensionally using three-dimensional computed tomography (3DCT), and to investigate the factors related to the occurrence of OLTs. Methods: The subjects were 19 patients (19 ankles) who underwent surgery for medial OLTs (OLT group). They included 13 men and 6 women. A healthy group without ankle disease served as a control group with the same number of 19 ankles. Three-dimensional ankle joint models were made based on DICOM data obtained with CT images. In the 3D model, the medial malleolus articular surface and the tibial plafond surface, the medial surface of the trochlea of the talus, and the lateral surface of the trochlea of the talus were defined. The tibial axis-medial malleolus (TMM) angle, the medial malleolus surface area (MMA), the medial malleolus volume (MMV), and the anterior opening angle of the talus were measured 3-dimensionally and compared in the OLT and control groups. Results: The mean TMM angle was significantly larger in the OLT group (34.2 ± 4.4°) than in the control group (29.2 ± 4.8°; p = 0.002). The mean MMA was significantly smaller in the OLT group (219.8 ± 42.4 mm2) than in the control group (280.5 ± 38.2 mm2; p < 0.001). The mean MMV was significantly smaller in the OLT group (2119.9 ± 562.5 mm3) than in the control group (2646.4 ± 631.4 mm3; p = 0.01). The mean anterior opening angle of the talus was significantly larger in the OLT group (15.4 ± 3.9°) than in the control group (10.2 ± 3.6°; p < 0.001). Conclusion: It was shown with 3DCT measurements that, in medial OLT patients, the medial malleolus opens distally, the MMA and MMV are small, and the talus anterior opening angle was significantly larger than in controls. This study suggests the possibility that the 3D bone morphology of both the mortise and tenon of the ankle joint are closely related to the occurrence of OLTs.

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Auschra, Clemens y Reimund Stadler. "Synthesis of block copolymers with poly(methyl methacrylate): P(B-b-MMA), P(EB-b-MMA), P(S-b-B-b-MMA) and P(S-b-EB-b-MMA)". Polymer Bulletin 30, n.º 3 (marzo de 1993): 257–64. http://dx.doi.org/10.1007/bf00343058.

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Song, Pei-Ni y Jin-Long Hong. "Highly-stretchable, self-healable random copolymers for loading large amounts of multiwall carbon nanotubes (MWCNTs) for the preparation of stretchable and healable electric sensors". Journal of Materials Chemistry C 7, n.º 42 (2019): 13161–75. http://dx.doi.org/10.1039/c9tc03735g.

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Pan, Chih-Hong, Ching-Yu Lin, Ching-Huang Lai y Hueiwang Anna Jeng. "Arsenic Exposure and Methylation Efficiency in Relation to Oxidative Stress in Semiconductor Workers". Atmosphere 11, n.º 5 (4 de mayo de 2020): 464. http://dx.doi.org/10.3390/atmos11050464.

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This study examined associations between oxidative stress and arsenic (As) exposure and methylation efficiency in semiconductor workers. An As-exposed group (n = 427) and a control group (n = 91) were included. The As-exposure group (n = 427) included 149 maintenance staff members and 278 production staff members representing high As exposure and low As exposure, respectively. The control group included 91 administrative staff members with no or minimal As exposure. An occupational exposure assessment was conducted to assess personal As exposure by measuring As concentrations in urine, hair, and fingernails of the subjects. Urinary As(III), As(V), monomethylarsonic (MMA), and dimethylarsinic acid (DMA) were quantified to assess an internal dose of inorganic As. Urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were measured to asses oxidative DNA damage and lipid peroxidation, respectively. As concentrations in urine, hair, and fingernails significantly increased (p < 0.05) in the As-exposed group in comparison to the control group. Geometric mean urinary concentrations of As, 8-OHdG, and MDA in the As-exposed group significantly exceeded those in the control group. As exposure to As-exposed workers had increased concentrations of 8-OHdG in contrast to those in control subjects. Moreover, urinary 8-OHdG concentrations in the semiconductor workers were positively correlated with urinary total As metabolite (As(III) + As(V) + MMA + DMA) concentrations. Furthermore, urinary excretion of 8-OHdG concentrations in As-exposed workers were positively associated with urinary excretion of MMA concentrations and primary methylation index values (the ration of MMA/inorganic As). However, fingernail and hair samples did not perform as well as urinary samples to measure oxidative stress induced by As exposure. 8-OHdG could serve as a more reliable biomarker for assessing As methylation than MDA did. Occupational exposure to inorganic As was associated with increased oxidative stress among semiconductor workers.

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Li, Xinxin, Yanhua Yang, Guojun Li y Shaoliang Lin. "Synthesis and self-assembly of a novel fluorinated triphilic block copolymer". Polym. Chem. 5, n.º 15 (2014): 4553–60. http://dx.doi.org/10.1039/c4py00308j.

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Wang, Zuochen, Jingjing Liu, Honghong Gong, Xiao Zhang, Junyong Lu y Zhicheng Zhang. "Synthesis of poly(methyl methacrylate–methallyl alcohol) via controllable partial hydrogenation of poly(methyl methacrylate) towards high pulse energy storage capacitor application". RSC Advances 6, n.º 41 (2016): 34855–65. http://dx.doi.org/10.1039/c6ra03757g.

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The first synthesis of poly(methyl methacrylate–methallyl alcohol) (P(MMA–MAA)) copolymersviaan indirect polymerization process involving the partial hydrogenation of PMMA with promising energy storage capability has been reported.

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van Loon, Saskia LM, Anna M. Wilbik, Uzay Kaymak, Edwin R. van den Heuvel, Volkher Scharnhorst y Arjen-Kars Boer. "Improved testing for vitamin B12 deficiency: correcting MMA for eGFR reduces the number of patients classified as vitamin B12 deficient". Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 55, n.º 6 (6 de junio de 2018): 685–92. http://dx.doi.org/10.1177/0004563218778300.

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Background Methylmalonic acid (MMA) can detect functional vitamin B12 deficiencies as it accumulates early when intracellular deficits arise. However, impaired clearance of MMA from blood due to decreased glomerular filtration rate (eGFR) also results in elevated plasma MMA concentrations. Alternative to clinical trials, a data mining approach was chosen to quantify and compensate for the effect of decreased eGFR on MMA concentration. Methods Comprehensive data on patient’s vitamin B12, eGFR and MMA concentrations were collected ( n = 2906). The relationship between vitamin B12, renal function (eGFR) and MMA was modelled using weighted multiple linear regression. The obtained model was used to estimate the influence of decreased eGFR on MMA. Clinical impact was examined by comparing the number of patients labelled vitamin B12 deficient with and without adjustment in MMA. Results Adjusting measured MMA concentrations for eGFR in the group of patients with low-normal vitamin B12 concentrations (90–300 pmol/L) showed that the use of unadjusted MMA concentrations overestimates vitamin B12 deficiency by 40%. Conclusions Through a data mining approach, the influence of eGFR on the relation between MMA and vitamin B12 can be quantified and used to correct the measured MMA concentration for decreased eGFR. Especially in the elderly, eGFR-based correction of MMA may prevent over-diagnosis of vitamin B12 deficiency and corresponding treatment.

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Solorio-Rodríguez, Luis Enrique y Alejandro Vega-Rios. "Filament Extrusion and Its 3D Printing of Poly(Lactic Acid)/Poly(Styrene-co-Methyl Methacrylate) Blends". Applied Sciences 9, n.º 23 (28 de noviembre de 2019): 5153. http://dx.doi.org/10.3390/app9235153.

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Herein, we report the melt blending of amorphous poly(lactide acid) (PLA) with poly(styrene-co-methyl methacrylate) (poly(S-co-MMA)). The PLAx/poly(S-co-MMA)y blends were made using amorphous PLA compositions from 50, 75, and 90wt.%, namely PLA50/poly(S-co-MMA)50, PLA75/poly(S-co-MMA)25, and PLA90/poly(S-co-MMA)10, respectively. The PLAx/poly(S-co-MMA)y blend pellets were extruded into filaments through a prototype extruder at 195 °C. The 3D printing was done via fused deposition modeling (FDM) at the same temperature and a 40 mm/s feed rate. Furthermore, thermogravimetric curves of the PLAx/poly(S-co-MMA)y blends showed slight thermal decomposition with less than 0.2% mass loss during filament extrusion and 3D printing. However, the thermal decomposition of the blends is lower when compared to amorphous PLA and poly(S-co-MMA). On the contrary, the PLAx/poly(S-co-MMA)y blend has a higher Young’s modulus (E) than amorphous PLA, and is closer to poly(S-co-MMA), in particular, PLA90/poly(S-co-MMA)10. The PLAx/poly(S-co-MMA)y blends proved improved properties concerning amorphous PLA through mechanical and rheological characterization.

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Syahputra, Muhammad Risfi. "Pengenalan Olahraga MMA Melalui Film Dokumenter “Fighter”". Inter Community: Journal of Communication Empowerment 3, n.º 1 (31 de mayo de 2022): 27. http://dx.doi.org/10.33376/ic.v3i1.973.

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Olahraga merupakan kegiatan yang sering dilakukan oleh semua orang, baik untuk kesehatan maupun untuk kepentingan lainya. Selain olahraga, beladiri juga banyak dilakukan, dengan tujuan untuk pertahanan diri. Bela diri yang banyak dilakukan seperti Karate, Silat, dan masih banyak lagi. Saat ini olahraga Mixed Martial Arts (MMA) sedang ramai di Indonesia. MMA merupakan jenis olahraga campuran yang didalamnya ada kontak fisik dan juga berbagai teknik, dan juga tidak banyak aturan tetap seperti olahraga lainya. Perkembangan MMA cukup baik, karena baik laki – laki atau perempuan mulai banyak yang berminat terhadap olahraga MMA. Tetapi sebagian masyarakat melihat bahwa MMA bukanlah salah satu olahraga, melainkan MMA merupakan ajang kekerasan. Oleh karena itu, pencipta karya membuat film dokumenter berjudul Fighter dengan gaya film dokumenter ekspositori. Tujuan dibuatnya film dokumenter ini untuk memberi informasi serta edukasi kepada masyarakat yang menganggap bahwa MMA adalah ajang kekerasan. Dalam film ini salah satu atlet MMA yang cukup terkenal di Indonesia, Theodorus Ginting akan menjelaskan seperti apa olahraga MMA yang sebenarnya. Alasan pencipta karya membuat film dokumenter karena dokumenter adalah sebuah tayangan yang menyajikan cerita sesuai dengan aslinya, tanpa ada yang dibuat – buat. Penonton juga akan mendapatkan audio dan visual yang bisa dirasakan secara nyata. Dalam karya ini, akan dilakukan wawancara dan juga mengikuti kegiatan atlit MMA guna mendapatkan jawaban yang diharapkan mengenai olahraga MMA. Pencipta karya berharap, dengan dibuatnya film dokumenter ini masyarakat bisa menghapus stigma negatif mengenai olahraga MMA, karena MMA merupakan olahraga yang didalamnya menjunjung tinggi nilai sportifitas dan bukan hanya kekerasan yang ada dalam MMA.

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César-Oliveira, Maria A. F., Soraia Zaioncz, Angelo R. S. Oliveira, Maria C. R. Almeida, Sônia F. Zawadzki, Leni Akcelrud, Marcelo Aguiar, David Tabak y Elizabete F. Lucas. "Síntese de copolímeros metacrílicos através da modificação química do poli(metacrilato de metila) de massa molar Controlada". Polímeros 9, n.º 4 (diciembre de 1999): 156–62. http://dx.doi.org/10.1590/s0104-14281999000400026.

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Poli(metacrilato de metila) (PMMA) de massa molar controlada foi sintetizado, em solução de tolueno, utilizando peróxido de benzoíla como iniciador e 1-dodecanotiol (DDM) como agente de transferência de cadeia. O efeito da concentração de DDM sobre a massa molar do PMMA foi investigado. Copolímeros de metacrilato de metila e ácido metacrílico, P(MMA-MAA), foram sintetizados a partir da hidrólise parcial de homopolímeros de metacrilato de metila com variadas massas molares. Utilizando uma técnica inédita na literatura para a síntese de ésteres poliméricos, foi realizada a reação das unidades ácidas do P(MMA-MAA) com álcoois de cadeia longa, na presença de 1,3-diciclo-carbodiimida e 4-dimetilamino-piridina, que produziu copolímeros contendo longos segmentos hidrocarbônicos pendentes, tais como o poli(metacrilato de metila-co-metacrilato de hexadecila).

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Venkatesan, Raja, Krishnapandi Alagumalai, Chaitany Jayprakash Raorane, Vinit Raj, Divya Shastri y Seong-Cheol Kim. "Morphological, Mechanical, and Antimicrobial Properties of PBAT/Poly (Methyl Methacrylate-co-Maleic Anhydride)–SiO2 Composite Films for Food Packaging Applications". Polymers 15, n.º 1 (26 de diciembre de 2022): 101. http://dx.doi.org/10.3390/polym15010101.

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A poly (methyl methacrylate-co-maleic anhydride) P(MMA-co-MA) copolymer was synthesized via radical polymerization. The synthesized P(MMA-co-MA) copolymer was identified by 1H- and 13C-nuclear magnetic resonance spectroscopy (1H-NMR), (13C-NMR), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The poly(butylene adipate-co-terephthalate) (PBAT)/P(MMA-co-MA)–SiO2 composites were developed using a solution-casting method. The PBAT to P(MMA-co-MA) weight ratio was kept at 70:30, while the weight percentage of SiO2 nanoparticles (NPs) was varied from 0.0 to 5.0 wt.%. SiO2 was used for PBAT/P(MMA-co-MA) to solve the compatibility between PBAT and the P(MMA-co-MA) matrix. The PBAT/P(MMA-co-MA)–SiO2 composites were characterized by studied FTIR spectroscopy, XRD, SEM, and TEM. A comparison of the composite film PBAT/P(MMA-co-MA)–SiO2 (PBMS-3) with the virgin PBAT and P(MMA-co-MA) film revealed its good tensile strength (19.81 MPa). The WVTR and OTR for the PBAT/P(MMA-co-MA)–SiO2 composites were much smaller than for PBAT/P(MMA-co-MA). The PBAT/P(MMA-co-MA)–SiO2 WVTR and OTR values of the composites were 318.9 ± 2.0 (cc m−2 per 24 h) and 26.3 ± 2.5 (g m−2 per 24 h). The hydrophobicity of the PBAT/P(MMA-co-MA) blend and PBAT/P(MMA-co-MA)–SiO2 composites was strengthened by the introduction of SiO2, as measured by the water contact angle. The PBAT/P(MMA-co-MA)–SiO2 composite films showed excellent antimicrobial activity against the food-pathogenic bacteria E. coli and S. aureus from the area of inhibition. Overall, the improved packaging characteristics, such as flexibility, tensile strength, low O2 and H2O transmission rate, and good antimicrobial activities, give the PBAT/P(MMA-co-MA)–SiO2 composite film potential for use in food packaging applications.

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Soykut, Buğra, Onur Erdem, Cemal Akay y Bülent Pişkin. "Investigation of the oxidative stress condition for occupational exposure to methyl methacrylate". Toxicology and Industrial Health 33, n.º 1 (28 de julio de 2016): 61–66. http://dx.doi.org/10.1177/0748233716659840.

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The purpose of this study is the evaluation of possible toxicological effects on dental personnel, who are exposed to the production materials of prostheses during their entire working life. In this study, the level of methyl methacrylate (MMA) in ambient air was measured as an indicator of external exposure on the personnel. In order to evaluate the possible toxic effects of oxidative stress, which is thought to play an important role in the formation process of many diseases such as cancer, blood samples of volunteers were examined via the ultraviolet-spectroscopic determination of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase antioxidant enzyme activities, comparing occupationally MMA-exposed ( n = 69) and control ( n = 67) groups. In these groups, malondialdehyde (MDA) and glutathione levels were also determined by the same method. The results showed that SOD activity and MDA and glutathione levels were significantly higher in the exposed group when compared with the control group ( p < 0.001). A significant decrease was determined in the glutathione peroxidase activities of the exposed group ( p < 0.05). No significant difference in CAT activities between the groups has been found. When the results obtained in the study are considered, it is suggested that an adaptive response might be developed by dental technicians against low-level MMA exposure.

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Chudzik, Patryk. "Middle Kingdom tombs from Asasif: work in the 2015/2016 season". Polish Archaeology in the Mediterranean 26, n.º 1 (9 de julio de 2018): 183–96. http://dx.doi.org/10.5604/01.3001.0012.1775.

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In the third season of the Polish Asasif Project at the North Asasif Necropolis in West Thebes archaeological fieldwork concentrated on six of the Middle Kingdom rock-cut tombs: MMA 508/TT 311, MMA 509, MMA 512, MMA 514, MMA 515 and MMA 517/TT 240. The corridors and chambers were cleared and the architecture documented and restored. A surface survey was carried out on the slope. Of greatest interest among the finds are Middle Kingdom stonemason’s tools and cartonnages from the Third Intermediate Period.

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Menezes, Ralciane de Paula, Mário Paulo Amante Penatti y Reginaldo dos Santos Pedroso. "Different culture media containing methyldopa for melanin production by Cryptococcus species". Revista da Sociedade Brasileira de Medicina Tropical 44, n.º 5 (octubre de 2011): 591–94. http://dx.doi.org/10.1590/s0037-86822011000500012.

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INTRODUCTION: Melanin production by species of Cryptococcus is widely used to characterize C. neoformans complex in mycology laboratories. This study aims to test the efficacy of methyldopa from pharmaceutical tablet as a substrate for melanin production, to compare the production of melanin using different agar base added with methyldopa, and to compare the melanin produced in those media with that produced in Niger seed agar and sunflower seed agar by C. neoformans, C. laurentii, and C. albidus. Two isolates of each species, C. neoformans, C. laurentii, and C. albidus, and one of Candida albicans were used to experimentally detect conditions for melanin production. METHODS: The following media were tested: Mueller-Hinton agar (MHA), brain and heart infusion agar (BHIA), blood agar base (BAB), and minimal medium agar (MMA), all added with methyldopa, and the media Niger seed agar (NSA) and sunflower seed agar (SSA). RESULTS: All isolates grew in most of the culture media after 24h. Strains planted on media BAB and BHIA showed growth only after 48h. All isolates produced melanin in MMA, MHA, SSA, and NSA media. CONCLUSIONS: Methyldopa in the form pharmaceutical tablet can be used as a substrate for melanin production by Cryptococcus species; minimal medium plus methyldopa was more efficient than the BAB, MHA, and BHIA in the melanin production; and NSA and SSA, followed by MMA added with methyldopa, were more efficient than other media studied for melanin production by all strains studied.

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Kokunesoski, Maja, Djordje Janackovic, Dusan Kicevic, Svetlana Ilic y Aleksandra Saponjic. "The effect of acrylate on the properties and machinability of alumina ceramics". Science of Sintering 55, n.º 1 (2023): 103–13. http://dx.doi.org/10.2298/sos2301103k.

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Effect of methyl methacrylate (MMA) as a binder and heating treatment were investigated to improve green alumina compacts machinability. Properties of green compacts and their corresponding sintered samples prepared with and without MMA were compared. Investigation of green and sintered properties was performed on samples compacted at applied pressures up to 150 MPa. After pressing, samples with MMA were thermally treated at 115oC. The intention was to enhance the polymerization of MMA at a temperature a little higher than the glass transition temperature (Tg = 103oC) of poly (methyl methacrylate). Green compacts with MMA had higher green density values than those without MMA. Sintered samples with MMA had lower values of sintered density and higher values of total porosity; after sintering, relative linear shrinkage was around 15 % for the whole range of applied pressures. The possibility of easily machining the green compacts with MMA produces great possibilities for application in many fields

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Amin, Faisal Mohammad, Mohammad Sohail Asghar, Julie W. Ravneberg, Patrick JH de Koning, Henrik BW Larsson, Jes Olesen y Messoud Ashina. "The effect of sumatriptan on cephalic arteries: A 3T MR-angiography study in healthy volunteers". Cephalalgia 33, n.º 12 (15 de abril de 2013): 1009–16. http://dx.doi.org/10.1177/0333102413483374.

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Aim To explore a possible differential effect of sumatriptan on extracerebral versus cerebral arteries, we examined the superficial temporal (STA), middle meningeal (MMA), extracranial internal carotid (ICAextra), intracranial internal carotid (ICAintra), middle cerebral (MCA) and basilar arteries (BA). Methods The arterial circumferences were recorded blindly using high-resolution magnetic resonance angiography before and after subcutaneous sumatriptan injection (6 mg) in 18 healthy volunteers. Results We found significant constrictions of MMA (16.5%), STA (16.4%) and ICAextra (15.2%) ( p ≤ 0.001). Smaller, but statistically significant, constrictions were seen in MCA (5.5%) and BA (2.1%) ( p ≤ 0.012). ICAintra change 1.8% was not significant ( p = 0.179). The constriction of cerebral arteries was significantly smaller than the constriction of extracerebral arteries ( p < 0.000001). Conclusion Sumatriptan constricts extracerebral arteries more than cerebral arteries. We suggest that sumatriptan may exert its anti-migraine action outside of the blood–brain barrier.

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Zhang, Xianfa, Jinsheng Sun, Zonglun Wang, Jingping Liu y Kaihe Lv. "Development and evaluation of a high temperature and high salinity resistant rheological enhancer for water-based drilling fluids". Journal of Physics: Conference Series 2353, n.º 1 (1 de octubre de 2022): 012001. http://dx.doi.org/10.1088/1742-6596/2353/1/012001.

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Abstract A rheology enhancer MMA for water-based drilling fluids was developed using acrylamide (AM), sodium p-styrenesulfonate (SSS), maleic anhydride (MA) and lauryl methacrylate (LMA). MMA has hydrophobic side chains that can form hydrophobic association structures in the drilling fluid, thus giving the drilling fluid the properties of NaCl-promoted viscosity enhancement. When the drilling fluid with 2% MAA was hot-rolling at 200°C and 30% NaCl for 16h, its apparent viscosity and yield point were 29.0 mPa·s and 12.0 Pa, respectively. Meanwhile, its rheological enhancement and viscosity retention properties were better than those of common oilfield products such as CMC, PAC and Driscal D at the same addition.

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Rasmussen, K., L. Moelby y M. K. Jensen. "Studies on methylmalonic acid in humans. II. Relationship between concentrations in serum and urinary excretion, and the correlation between serum cobalamin and accumulation of methylmalonic acid." Clinical Chemistry 35, n.º 12 (1 de diciembre de 1989): 2277–80. http://dx.doi.org/10.1093/clinchem/35.12.2277.

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Abstract Methylmalonic acid (MMA) concentrations are increased in cobalamin (vitamin B12) deficiency, but the relative diagnostic usefulness of determination of MMA in serum vs urine has not yet been assessed. We obtained urine collections and matched serum samples from 28 healthy volunteers and from 20 consecutive patients admitted for clinical and hematological evaluation because of low cobalamin concentrations in serum. Increased concentrations of MMA in serum were found in 12 patients, in all of whom a clinical diagnosis of cobalamin deficiency was established. By contrast, cobalamin deficiency was excluded in seven of the eight remaining patients, who all had normal MMA concentrations. Here we report that linear relationships exist between MMA concentrations in serum (investigated range: 0.05-34.2 mumol/L) and MMA concentrations in urine (r = 0.74), concentrations relative to creatinine (r = 0.98), and MMA excretion rates (r = 0.97) (P less than 0.001 in each instance). Our data are consistent with glomerular filtration and passive reabsorption of MMA by the tubules. We demonstrate, for the first time, a negative correlation between concentrations of cobalamin and MMA in serum in clinical cobalamin deficiency (r = -0.69; P less than 0.01; n = 12); when the values for MMA were log transformed, the correlation with cobalamin was much better (r = -0.84; P less than 0.0005).

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Hinther, Ashley, Steven C. Nakoneshny, Shamir P. Chandarana, T. Wayne Matthews, Robert Hart, Christiaan Schrag, Jennifer Matthews, C. David McKenzie, Gordon H. Fick y Joseph C. Dort. "Efficacy of Multimodal Analgesia for Postoperative Pain Management in Head and Neck Cancer Patients". Cancers 13, n.º 6 (12 de marzo de 2021): 1266. http://dx.doi.org/10.3390/cancers13061266.

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Postoperative opioid use has been linked to the subsequent development of opioid dependency. Multimodal analgesia (MMA) can reduce the use of opioids in the postoperative period, but MMA has not been well-studied after major head and neck surgery. Our goal is to explore the association between MMA and postoperative opioid use and pain control in patients undergoing major head and neck surgery. We performed a retrospective study in adult (age ≥ 18 years) patients undergoing primary head and neck cancer resection with free-flap reconstruction. All patients were treated using an established care pathway. The baseline group was treated between January 2015–December 2015 (n = 41), prior to the implementation of MMA, and were compared to an MMA-treated cohort treated between December 2017–June 2019 (n = 97). The primary outcome was the proportion of opioids prescribed and oral morphine equivalents (OMEs) consumed during the hospitalization. The secondary outcome was pain control. We found that the post-MMA group consumed fewer opioids in the postoperative period compared to the pre-MMA group. Prior to post-operative day (POD) 6, pain control was better in the post-MMA group; however, the pain control lines intersect on POD 6 and the pre-MMA group appeared to have better pain control from PODs 7–10. In conclusion, our data suggest MMA is an effective method of pain control and opioid reduction in patients undergoing surgery for head and neck cancer with free flap reconstruction. MMA use was associated with a significant decrease in the quantity of opioids consumed postoperatively. The MMA protocol was associated with improved pain management early in the postoperative course. Finally, the MMA protocol is a feasible method of pain control and may reduce the adverse side effects associated with opioid use.

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Zhang, Yujuan, Chunhong Wang, Defeng Wu, Xintao Guo, Lei Yu y Ming Zhang. "Probing the effect of straight chain fatty acids on the properties of lead-containing plexiglass". Reaction Chemistry & Engineering 6, n.º 9 (2021): 1628–34. http://dx.doi.org/10.1039/d1re00154j.

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By adding saturated straight chain fatty acids into the reaction system of Pb(MAA)2 with MMA, the prepared lead-containing plexiglass possessed excellent optical properties. It may provide key techniques for fabricating γ-ray shielding plexiglasses.

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Bashar, A. S., M. A. Khan y K. M. Idriss Ali. "Bamboo-Plastic Composite with MMA". Polymer-Plastics Technology and Engineering 35, n.º 4 (julio de 1996): 581–90. http://dx.doi.org/10.1080/03602559608000594.

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ROSENBAUM, STUART. "The Wisdom of Mma Ramotswe". Pluralist 3, n.º 3 (1 de octubre de 2008): 79–94. http://dx.doi.org/10.2307/20708949.

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Periac, Ianis. "Ronda Rousey, pionnière du MMA". PANARD N° 4, n.º 2 (16 de octubre de 2023): 34–45. http://dx.doi.org/10.3917/pan.004.0034.

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