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1
Adedayo, Sosina. "Need Assessment of Farmers in Crop-Livestock Production Systems in Ido Local Government Area, Oyo State, Nigeria." International Journal of Agricultural Extension 7, no. 2 (2019): 177–86. http://dx.doi.org/10.33687/ijae.007.02.2730.
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Agricultural projects and programmes funded by governments and donor agencies often failed to achieve the desired set objective(s) at the system levels. The study tries to assess the existing production practices with a view of coming up with a consensus farmer need in a crop-livestock production system at Ido Local Government Area (LGA). The study used a three-stage-sampling technique to elicit information from 225 respondents. Ido Local Government Area was purposively selected for the study. Three cells were randomly selected for the research, three villages were randomly selected in each cell and twenty-five farmers were selected using the snowball selection technique. The data obtained from the Participatory Rural Appraisal were analyzed using descriptive statistics. The pairwise ranking tool helped in determining the importance of the identified problems from the FGD in the study area. The researcher identified the following problems (Pb) from the focus group discussion; inadequate capital for livestock production (Pb1), poor housing for livestock (Pb2), inadequate nutrition for livestock (Pb3), diseases of crops (Pb4), livestock and predatory attack on crops (Pb5). The pairwise comparison of percentage of Pb1 versus (vs) Pb2 was 80/20%, Pb1 vs Pb3 was 68/32%, Pb1 vs Pb4 was 80/20%, Pb1 vs Pb5 was 12/88%, Pb2 vs Pb3 was 68/32%, Pb2 vs Pb4 was 20/80%, Pb2 vs Pb5 was 20/80%, Pb3 vs Pb4 was 32/68%, Pb3 vs Pb5 was 20/80%, vs Pb4 vs Pb5 was 20/80% respectively. The ultimate farmers’ problem in crop-livestock production systems (CLPS) that needs immediate intervention and technical assistance was inadequate capital as perceived from the responses of the farmers.
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Mendoza-Wilson, Ana María, and René Renato Balandrán-Quintana. "Effect of Constituent Units, Type of Interflavan Bond, and Conformation on the Antioxidant Properties of Procyanidin Dimers: A Computational Outlook." Journal of Chemistry 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/3535148.
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Procyanidin (PC) dimers are powerful antioxidants, abundant in plant tissues, and also bioavailable. However, the role of the molecular structure of PCs on their antioxidant properties is still a controversial and not fully understood issue that needs to be addressed in a more specific way. The objective of this study was to analyze the effect of the constituent units, type of interflavan bond, and conformation on the antioxidant properties of PC dimers including PB3, PB4, PB5, PB6, PB7, and PB8, using the density functional theory (DFT) computational method. The analysis was performed in function of parameters that allow determining the ability of the molecules to transfer or to capture electrons, among which the chemical potential, bond dissociation enthalpy (BDE), gap energy, Fukui indices, and charge distribution of HOMO-LUMO orbitals. The factors that showed the most notable effects on the antioxidant properties of the PC dimers were the type of interflavan bond and the conformation. The antioxidant ability of the dimers PB3 and PB4 containing the interflavan bond C4–C8, in their Compact conformation, was very similar to each other but greater than those of dimers PB5, PB6, PB7, and PB8 containing the C4–C6 interflavan bond. PB8 showed the lowest antioxidant ability.
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Sosina, A. O., and O. J. Babayemi. "Assessment of farmers' needs in Ibarapa East Local Government area of Oyo State, Nigeria." Nigerian Journal of Animal Production 47, no. 5 (2020): 92–100. http://dx.doi.org/10.51791/njap.v47i5.1352.
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Government and non-government organizations (NGOs) interventions to local farmers in the recent past had not yielded the desired result because these interventions were not tailored towards the needs of farmers. However, most information on the needs of target farmers have been very scanty thus, the need to use a bottom top approach to assess farmers' needs in Ibarapa East, Oyo state. A three-stage sampling technique was used to purposively select about 225 respondents. Parameters measured were household characteristics, farm sizes, farm labor availability, seasonal pattern and need to be assessed using a participatory rural appraisal approach comprising of focus group discussion (FGD) and structured questionnaire. Data were analyzed descriptively and the need assessed using the pair-wise ranking and simple matrix. Of challenges listed in FDG among crop-livestock farmers, only five (5) were prioritized as follows; wastage of agricultural products (Pb1), bad road network (Pb2), high cost of agricultural inputs (Pb3), lack of potable water (Pb4) and animal invasion (Pb5). The pairwise comparison of the percentage of Pb1 versus (vs.) Pb2 was 80/20%, Pb1 vs. Pb3 was 90/10%, Pb1 vs. Pb4 was 70/30%, Pb1 vs. Pb5 was 20/80%, Pb2 vs. Pb3 was 70/30%, Pb2 vs Pb4 was 30/70%, Pb2 vs. Pb5 was 10/90%, Pb3 vs. Pb4 was 20/80%, Pb3 vs. Pb5 was 10/90%, vs. Pb4 vs Pb5 was 30/70%, respectively. There were proffered solutions to the problem(s) itemized by the FGD. The animal invasion was ranked highest as farmers' need assessed for possible intervention in Ibarapa East. Governments and NGO funds should be addressing animal invasion for desirable project impact assessment. Les interventions des gouvernements et des organisations non gouvernementales (ONG) auprès des agriculteurs locaux dans un passé récent n'avaient pas donné le résultat souhaité car ces interventions n'étaient pas adaptées aux besoins des agriculteurs. Cependant, la plupart des informations sur les besoins des agriculteurs cibles ont été très rares, ce qui nécessite d'utiliser une approche ascendante pour évaluer les besoins des agriculteurs de l'est d'Ibarapa, dans l'État d'Oyo. Une technique d'échantillonnage en trois étapes a été utilisée pour sélectionner environ 225 répondants. Les paramètres mesurés étaient les caractéristiques des ménages, la taille des exploitations, la disponibilité de la main-d'oeuvre agricole, le profil saisonnier. Ils doivent être évalués à l'aide d'une approche d'évaluation rurale participative comprenant des discussions de groupe et un questionnaire structuré. Les données ont été analysées de manière descriptive et le besoin évalué en utilisant le classement par paires et une matrice simple. Parmi les défis énumérés dans le 'FDG' chez les agriculteurs et les éleveurs, seuls cinq (5) ont été classés comme suit; gaspillage des produits agricoles (le 'Pb' 1), mauvais réseau routier (le 'Pb' 2), coût élevé des intrants agricoles (le 'Pb' 3), manque d'eau potable (le 'Pb' 4) et invasion animale (le 'Pb' 5). La comparaison par paire du pourcentage de 'Pb' 1 versus (vs) 'Pb' 2 était de 80/20%, Pb1 vs Pb3 était de 90/10%, Pb1 vs Pb4 était de 70/30%, Pb1 vs Pb5 était de 20/80% Pb2 vs Pb3 était de 70/30%, le 'Pb' 2 vs le 'Pb4' était de 30/70%, le 'Pb' 2 vs le 'Pb' 5 était de 10/90%, le 'Pb' 3 vs. le 'Pb' 4 était de 20/80%, le 'Pb' 3 vs. le 'Pb' 5 etaient 10/90%,vs le 'Pb' 4 vs le 'Pb'5 était respectivement de 30/70%. Des solutions ont été proposées au (x) problème (s) détaillé (s) par le FGD. L'invasion animale a été classée au premier rang des besoins des agriculteurs évalués pour une éventuelle intervention à l'Estd'Ibarapa. Les gouvernements et les fonds d'ONG devraient s'attaquer à l'invasion animale pour une évaluation de l'impact souhaitable du projet.
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Ntita, Mbaya, Shin-Ichi Inoue, Jiun-Yu Jian, et al. "Type I interferon production elicits differential CD4+ T-cell responses in mice infected with Plasmodium berghei ANKA and P. chabaudi." International Immunology 34, no. 1 (2021): 21–33. http://dx.doi.org/10.1093/intimm/dxab090.
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Abstract Abstract Plasmodium parasites that infect humans are highly polymorphic, and induce various infections ranging from an asymptomatic state to life-threatening diseases. However, how the differences between the parasites affect host immune responses during blood-stage infection remains largely unknown. We investigated the CD4+ T-cell immune responses in mice infected with P. berghei ANKA (PbA) or P. chabaudi chabaudi AS (Pcc) using PbT-II cells, which recognize a common epitope of these parasites. In the acute phase of infection, CD4+ T-cell responses in PbA-infected mice showed a lower involvement of Th1 cells and a lower proportion of Ly6Clo effector CD4+ T cells than those in Pcc-infected mice. Transcriptome analysis of PbT-II cells indicated that type I interferon (IFN)-regulated genes were expressed at higher levels in both Th1- and Tfh-type PbT-II cells from PbA-infected mice than those from Pcc-infected mice. Moreover, IFN-α levels were considerably higher in PbA-infected mice than in Pcc-infected mice. Inhibition of type I IFN signaling increased PbT-II and partially reversed the Th1 over Tfh bias of the PbT-II cells in both PbA- and Pcc-infected mice. In the memory phase, PbT-II cells in PbA-primed mice maintained higher numbers and exhibited a better recall response to the antigen. However, recall responses were not significantly different between the infection groups after re-challenge with PbA, suggesting the effect of the inflammatory environment by the infection. These observations suggest that the differences in Plasmodium-specific CD4+ T-cell responses between PbA- and Pcc-infected mice were associated with the difference in type I IFN production during the early phase of the infection.
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Chaiwat, Weerawut, Pimonpan Inthapat, Suwanna Boontanon, et al. "PRODUCTION OF TORREFIED BIOMASS PELLETS FROM WOODY AND AGRICULTURAL RESIDUES (TIChE2021)." Suranaree Journal of Science and Technology 30, no. 3 (2023): 010232(1–13). http://dx.doi.org/10.55766/sujst-2023-03-e0912.
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Two different combined process sequences of biomass pretreatment between pelletization after torrefaction (PAT) and pelletization before torrefaction (PBT) were comparatively investigated to produce torrefied biomass pellets (TBP) from woody biomasses, e.g. Leucaena (LC) and rubberwood (RW), and agricultural residues, e.g. rice straw (RS) and sugarcane leaves (SCL). In this study, each sample was thermally treated at 260-300°C for 5 min during torrefaction process. It was found that both woody biomasses and agricultural residues had mass yield lower than 63wt%, while the bulk density of TBPs were improved higher than 400kg/m3. For equilibrium moisture content (EMC) analysis, TBPs via PBT method had lower EMC than raw pellet after being kept at 30°C for 12 days. For the thermochemical properties, the TBPs had higher FC, %C, and HHVs than raw pellets in all biomasses and increased with torrefaction temperature. When comparing the TBPs between PAT and PBT torrefied pellets, the HHVs of PBT torrefied pellets at 300°C were achieved highest at 27 MJ/kg for SCL sample, leading to lower H/C and O/C ratio closely to that of lignite. In addition, the combustion performance index (Sn) of PAT and PBT torrefied pellets was lower than raw pellets, showing a similar property as coal and lignite. Briefly, this study suggests using PBT pretreatment process to produce high quality solid fuel, particularly for agricultural residues such as SCL for a potential substitute of currently used coal.
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Xu, Jian Lin, Bing Xue Ma, Cheng Hu Kang, Cheng Cheng Xu, Zhou Chen, and Yong Gang Lin. "Thermal Decomposition Kinetics of Flame Retardant Polybutylene Terephthalate Matrix Composites." Materials Science Forum 956 (June 2019): 181–91. http://dx.doi.org/10.4028/www.scientific.net/msf.956.181.
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The thermal decomposition kinetics of polybutylene terephthalate (PBT) and flame-retardant PBT (FR-PBT) were investigated by thermogravimetric analysis at various heating rates. The kinetic parameters were determined by using Kissinger, Flynn-Wall-Ozawa and Friedman methods. The y (α) and z (α) master plots were used to identify the thermal decomposition model. The results show that the rate of residual carbon of FR-PBT is higher than that of PBT and the maximum mass loss rate of FR-PBT is lower than that of PBT. The values of activation energy of PBT (208.71 kJ/mol) and FR-PBT (244.78 kJ/mol) calculated by Kissinger method were higher than those of PBT (PBT: 195.54 kJ/mol) and FR-PBT (FR-PBT: 196.00 kJ/mol) calculated by Flynn-Wall-Ozawa method and those of PBT and FR-PBT (PBT: 199.10 kJ/mol, FR-PBT: 206.03 kJ/mol) calculated by Friedman methods. There is a common thing that the values of activation energy of FR-PBT are higher than that of PBT in different methods. The thermal decomposition reaction models of the PBT and FR-PBT can be described by Avarami-Erofeyev model (A1).
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Shin, Hyeyoung, and Eun-Soo Park. "Mechanical and dielectric breakdown properties of PBT/TPE, PBT/PBT/PET, and PBT/antioxidant blends." Journal of Applied Polymer Science 114, no. 5 (2009): 3008–15. http://dx.doi.org/10.1002/app.30930.
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Wei, Xi, Chunyang Zhang, Depeng Gong, et al. "A Study on the Impermeability of Nanodispersible Modified Bentonite Based on Colloidal Osmotic Pressure Mechanisms and the Adsorption of Harmful Substances." Nanomaterials 13, no. 12 (2023): 1840. http://dx.doi.org/10.3390/nano13121840.
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With the growing demands of human beings, sanitary landfill, along with the increase in landfill depth and leachate water pressure, has put forward new and higher requirements for the impermeable layer. In particular, it is required to have a certain adsorption capacity of harmful substances from the perspective of environmental protection. Hence, the impermeability of polymer bentonite–sand mixtures (PBTS) at different water pressure and the adsorption properties of polymer bentonite (PBT) on contaminants were investigated through the modification of PBT using betaine compounded with sodium polyacrylate (SPA). It was found that the composite modification of betaine and SPA could reduce the average particle size of PBT dispersed in water (reduced to 106 nm from 201 nm) and enhance the swelling properties. As the content of SPA increased, the hydraulic conductivity of PBTS system decreases and the permeability resistance improves, while the resistance to external water pressure increases. It is proposed a concept of the potential of osmotic pressure in a constrained space to explain the impermeability mechanism of PBTS. The potential of osmotic pressure obtained by linear extrapolation of the trendline of colloidal osmotic pressure versus mass content of PBT could represent the external water pressure that the PBT resist. Additionally, the PBT also has a high adsorption capacity for both organic pollutants and heavy metal ions. The adsorption rate of PBT was up to 99.36% for phenol; up to 99.9% for methylene blue; and 99.89%, 99.9%, and 95.7% for low concentrations of Pb2+, Cd2+, and Hg+, respectively. This work is expected to provide strong technical support for the future development in the field of impermeability and removal of hazardous substances (organic and heavy metals).
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Wang, Ping, Li Hua Cheng, and Jian Qing Zhao. "Study on the Reaction and Thermo-Physical Properties of PC and PBT Blend." Advanced Materials Research 472-475 (February 2012): 1831–36. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.1831.
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Blends of polycarbonate (PC) and poly(butylene terephthalate) (PBT) were investigated. For 40 wt % PBT, it forms a continuous phase, the glass transition temperature (Tg) shifts to the lower temperature region. This direct comparison of XRD patterns of pure PBT and PBT containing 1.1% TPPi studied the impact of the crystallization of PBT and TPPi. We can see that diffraction peaks of XRD diagram of PBT/TPPi were broadened. When PBT content was added to 1.1% TPPi, the FWHM increases from 3.8 to 4.2 when diffraction angle was in the range of 16.9 degrees to 17.1 degrees. Thus, the addition of TPPi resulted in the small spherulite size of PBT phase, thus elaborating the sample transparency phenomenon.
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Yoo, Gyu Sang, Jeong Il Yu, Hee Chul Park, et al. "Do Biliary Complications after Proton Beam Therapy for Perihilar Hepatocellular Carcinoma Matter?" Cancers 12, no. 9 (2020): 2395. http://dx.doi.org/10.3390/cancers12092395.
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We aimed to evaluate the biliary complications and efficacy of proton beam therapy (PBT) for hepatocellular carcinoma (HCC). We retrospectively analyzed 167 patients who received PBT with ≥ 75 GyRBE of biological effective dose with ?/β = 10 for primary HCC. The perihilar region was defined as a 1-cm area extending from the right, left, and common hepatic ducts, including the gallbladder and cystic duct. PBT-related biliary complications were defined as follows: significant elevation in bilirubin level to > 3.0 mg/dL; elevation to more than twice of the baseline level after the completion of PBT; or newly developed radiological biliary abnormalities, which were not caused by HCC progression, comorbidities, or other treatments. Eighty (47.9%) had perihilar HCC. PBT-related events occurred in seven (4.2%), three of whom had perihilar HCC. Radiologic biliary abnormalities developed in 12 patients (7.2%); however, no events were PBT-related. All patients who experienced PBT-related biliary complications had underlying liver cirrhosis. The albumin-bilirubin grade was identified as an independent factor associated with PBT-related biliary complications. PBT at the current dose showed a low rate of PBT-related biliary complications even for patients with perihilar HCC. PBT for HCC patients with risk factors requires attention to reduce PBT-related biliary complications.
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Pham, Nga Thi-Hong, Van Tron Tran, Vo Xuan Tien, et al. "Study on recycling of Poly(butylene Terephthalate) and Polypropylene blend." Journal of Physics: Conference Series 2047, no. 1 (2021): 012005. http://dx.doi.org/10.1088/1742-6596/2047/1/012005.
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Abstract Poly (butylene terephthalate) (PBT) is a breakable plastic because its high modulus value makes it unsuitable for specific applications. Recycling PBT is even more complicated when the color is no longer the original milky white. This study takes R-PBT from the brush hair scraps and blends with 10% Polypropylene (PP). The results show that the mold continually adhered to is challenging to inject the sample 100% R-PBT. The surface of sample R-PBT / 10% PP has a good gloss and smooth texture, while there is a high shrinkage rate in sample 100% PP. The hardness of sample R-PBT / 10% PP is increased when adding PP. In addition, sample 100% R-PBT has a distinctive shape with tiny fibers, while model 100% PP has a flat surface. For the R-PBT / 10% PP sample, the microstructure has two distinct regions: PBT matrix and PP dispersed-droplets.
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Tamura, Shunsuke, Yukiyasu Okamura, Teiichi Sugiura, et al. "The comparisons of the outcomes between surgical resection and proton beam therapy for single primary hepatocellular carcinoma." Journal of Clinical Oncology 38, no. 4_suppl (2020): 482. http://dx.doi.org/10.1200/jco.2020.38.4_suppl.482.
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482 Background: There are many treatment choices for hepatocellular carcinoma (HCC). Proton beam therapy (PBT) is considered a treatment option for HCC. The purpose of this study was to compare surgical resection (SR) and PBT in order to clarify the prognostic factors for operable HCC based on a single institution’s database. Methods: Patients with single primary nodular HCC ≤ 100 mm without vessel invasion on pretreatment imaging were divided into the SR group and PBT group. In the PBT group, the patients with unresectable HCC due to their liver function and/or performance status (PS) were excluded. Results: There were 314 and 31 patients who underwent SR and PBT, respectively. The median survival time in the SR group was significantly better than in the PBT group (104.1 vs. 64.6 months, p = 0.008). Regarding the relapse-free survival (RFS), there was no significant difference between the SR and PBT groups (33.8 vs. 14.0 months, p = 0.099). Conclusions: In RFS, the PBT group and the SR group were comparable. However, the PBT group was significantly worse than SR group in overall survival. SR may therefore be favorable as an initial treatment for HCC compared to PBT. Clinical trial information: 1856.
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Xu, Jianlin, Bingxue Ma, Lei Niu, Chengcheng Xu, Zhou Chen, and Yonggang Lin. "Study on the flame retardancy of nano-Sb2O3/BPS-PBT composites." Advanced Composites Letters 28 (January 1, 2019): 096369351986574. http://dx.doi.org/10.1177/0963693519865743.
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To improve the flame retardancy of polybutylene terephthalate (PBT), PBT-based flame retardant composites containing antimony trioxide nanoparticles (nano-Sb2O3) and brominated polystyrene (BPS) were investigated. Nano-Sb2O3, BPS, and PBT were dispersed by ball milling method to obtain composite powders, and the nano-Sb2O3/BPS-PBT samples were prepared by melt blending and injection molding methods. The flame retardancy of nano-Sb2O3/BPS-PBT composites was investigated. The results showed that nano-Sbs2O3 can obviously improve the flame retardancy of PBT-based composites. When the nano-Sb2O3/BPS-PBT composite contains nano-Sb2O3 with 5 wt% of mass fraction and BPS with 10 wt% of mass fraction, the nano-Sb2O3/BPS-PBT composite has excellent flame retardancy, in which the UL94 degree of flame retardancy achieves V-0 grade and the limit oxygen index is 28.3%.
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Pham, Nga Thi-Hong, and Van-Thuc Nguyen. "Morphological and Mechanical Properties of Poly (Butylene Terephthalate)/High-Density Polyethylene Blends." Advances in Materials Science and Engineering 2020 (December 14, 2020): 1–9. http://dx.doi.org/10.1155/2020/8890551.
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Poly (butylene terephthalate) (PBT) is a popular thermoplastic polyester resin but has low strength and low melting point. To improve its properties, PBT is often mixed with other resins, such as high-density polyethylene (HDPE). In this study, PBT/HDPE samples with 100% PBT, 5%, 10%, 15%, and 100% HDPE are generated and tested. The samples are analyzed by tensile strength, flexural strength, impact strength, and SEM tests. Adding HDPE will reduce tensile strength compared to pure PBT, in which 5%, 10%, and 15% PBT/HDPE samples obtain the values 40.23, 38.11, and 27.77 MPa, respectively. These values are lower than that of pure PBT but still higher than that of HDPE. Improving the HDPE portion mostly results in decreasing flexural strength. The flexural strengths of these samples are 87.79, 70.47, 55.3, 58.98, and 19.14 MPa corresponding to 100% PBT, 5%, 10%, 15%, and 100% HDPE samples, respectively. Moreover, the SEM microstructure of PBT and HDPE indicates a two-phase heterogeneous mixture with little or no adhesion between these phases.
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Sultan, Saad Raheem, Amer Aziz Abdul-rahman, and Ayad Dari Jaafar. "Non-Isothermal Crystallization Kinetics Model of PBT/ MWCNTs Nanocomposites." Journal of Engineering 23, no. 3 (2017): 35–45. http://dx.doi.org/10.31026/j.eng.2017.03.03.
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The non-isothermal crystallization kinetics and crystalline properties of nanocomposites poly butyleneterephthalate, [PBT] /multiwalled-carbon nanotubes (MWCNTs) were tested by differential scanning calorimetry (DSC). PBT/(MWCNTs) nanocomposite was prepared by ultrasonicated of MWCNTs (0.5, 1, 2, 4 wt %) in dichloromethane (DCM) and after that the powdered PBT polymer was added to the MWCNTs solution. The non-isothermal crystallization results show that increasing the MWCNTs contents, decreased the melting temperature (Tm) of PBT/(MWCNTs) nanocomposite as compared with pure PBT, while resulting in improving the degree of crystallinity. These results indicated that a little amount of MWCNTs can be evident strong nucleating agent in PBT nanocomposites. Avrami kinetics model results given a good agreement with the frequent investigation. The Kissinger method shows the MWCNTs had a well nucleation effect on the crystallization of PBT, and the enhancement activation energy (Ea) with increased the MWCNTs in PBT/ (MWCNTs) nanocomposite.
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Ohki, Yuriko, Yohei Ogiwara, and Kotohiro Nomura. "Depolymerization of Polyesters by Transesterification with Ethanol Using (Cyclopentadienyl)titanium Trichlorides." Catalysts 13, no. 2 (2023): 421. http://dx.doi.org/10.3390/catal13020421.
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Exclusive chemical conversions of polyesters [poly(ethylene adipate) (PEA), poly(butylene adipate) (PBA), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT)] to the corresponding monomers (diethyl adipate, diethyl terephthalate, ethylene glycol, 1,4-butane diol) by transesterification with ethanol using Cp’TiCl3 (Cp’ = Cp, Cp*) catalyst have been demonstrated. The present acid-base-free depolymerizations by Cp’TiCl3 exhibited completed conversions (>99%) of PET, PBT to afford diethyl terephthalate and ethylene glycol or 1,4-butane diol exclusively (selectivity >99%) without formation of any other by-products in the NMR spectra (150–170 °C, Ti 1.0, or 2.0 mol%). The resultant reaction mixture after the depolymerization of PBA with ethanol via the CpTiCl3 catalyst (1.0 mol%, 150 °C, 3 h), consisting of diethyl adipate and 1,4-butane diol, was heated at 150 °C in vacuo for 24 h to afford high molecular weight recycled PBA with unimodal molecular weight distribution (Mn = 11,800, Mw/Mn = 1.6), strongly demonstrating a possibility of one-pot (acid-base-free) closed-loop chemical recycling.
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Shen, Zhiyuan, Faliang Luo, Jianghua Du, Xiaomei Lei, and Lijie Ji. "Studies on the effects of 4,4′-dihydroxyphenyl on crystallization and melting behavior of poly (butylene terephthalate)." Journal of Polymer Engineering 37, no. 8 (2017): 747–55. http://dx.doi.org/10.1515/polyeng-2016-0206.
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Abstract The blends of poly (butylene terephthalate) (PBT) and 4,4′-dihydroxyphenyl (DHP) were prepared by melt blending, and the effects of DHP on the crystallization and melting behaviors of PBT were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and polarized optical microscopy (POM). The results showed that crystallization temperature and crystallinity of PBT apparently decreased with the addition of DHP. A remarkably decline in crystallization rate of PBT was achieved, and the blends had higher σe and q values than that of pure PBT as analyzed based on the Avrami equation and Lauritzen-Hoffman equation. The crystal structure of PBT did not change by the addition of DHP, while the spherulite size of PBT decreased.
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Saini, Gagan, Rashmi Shukla, Kanika S. Sood, Sujit K. Shukla, and Ritu Chandra. "Role of Proton Beam Therapy in Current Day Radiation Oncology Practice." Asian Journal of Oncology 06, no. 03 (2020): 097–106. http://dx.doi.org/10.1055/s-0040-1713703.
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AbstractProton beam therapy (PBT), because of its unique physics of no–exit dose deposition in the tissue, is an exciting prospect. The phenomenon of Bragg peak allows protons to deposit their almost entire energy towards the end of the path of the proton and stops any further dose delivery. Braggs peak equips PBT with superior dosimetric advantage over photons or electrons because PBT doesn’t traverse the target/body but is stopped sharply at an energy dependent depth in the target/body. It also has no exit dose. Because of no exit dose and normal tissue sparing, PBT is hailed for its potential to bring superior outcomes. Pediatric malignancies is the most common malignancy where PBT have found utmost application. Nowadays, PBT is also being used in the treatment of other malignancies such as carcinoma prostate, carcinoma breast, head and neck malignancies, and gastrointestinal (GI) malignancies. Despite advantages of PBT, there is not only a high cost of setting up of PBT centers but also a lack of definitive phase-III data. Therefore, we review the role of PBT in current day practice of oncology to bring out the nuances that must guide the practice to choose suitable patients for PBT.
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Liu, Bo, and Wei Wu. "Influence of epoxidized ethylene propylene diene rubber on nonisothermal crystallization kinetics and mechanical properties of poly(butylene terephthalate)/polypropylene blend." Journal of Polymer Engineering 39, no. 3 (2019): 216–27. http://dx.doi.org/10.1515/polyeng-2018-0283.
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Abstract The epoxidized ethylene propylene diene rubber (eEPDM) was successfully prepared by the epoxidation of ethylene propylene diene rubber (EPDM) using t-butyl hydroperoxide as the oxidant in association with molybdenum oxide as the catalyst and characterized by Fourier-transform infrared (FTIR) spectrometer and 1H-nuclear magnetic resonance analyses. Then the poly(butylene terephthalate) (PBT)/eEPDM/polypropylene (PP) blends with different eEPDM contents were prepared using a twin-screw extruder, and the effect of eEPDM on nonisothermal crystallization kinetics of PBT/PP blend was investigated by differential scanning calorimetry. Meanwhile, morphological features of samples were observed using scanning electron microscopy. Also, the mechanical properties of samples were evaluated. Analyses of the crystallization data by various macro-kinetic models like Jeziorny modified Avrami and Liu-Mo model demonstrated that PP as diluents accelerated the crystallization of PBT in PBT/PP. Moreover, the addition of eEPDM into PBT/PP further facilitated the crystallization of PBT in PBT/eEPDM/PP. The eEPDM was an effective crystallization promoter for PBT/PP blend. And the presence of eEPDM promoted the uniform dispersion of PP in PBT matrix. When the content of eEPDM was 5 phr, the PBT/eEPDM/PP exhibited the highest notched impact strength and Young’s modulus among all the specimens.
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Gardette, Jean-Luc. "Photo-ageing of Poly(Butylene Terephthalate) and Poly(Butylene Terephthalate)-Fibre Glass Systems." Engineering Plastics 5, no. 1 (1997): 147823919700500. http://dx.doi.org/10.1177/147823919700500102.
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The photolysis and photo-oxidation mechanisms of poly(butylene terephthalate) (PBT) and poly(butylene terephthalate)-fibre glass (PBT-FG) irradiated under polychromatic light (λ ≥ 2300 nm) were studied. Derivatisation reactions coupled to FTIR analysis of the exposed samples permitted the identification of the various photo-products and the proposal of mechanisms. It was found that the same photo-products were formed in PBT and PBT-FG. Micro-FTIR analysis of the irradiated samples showed that the photochemical reactions were limited to a depth of 50 urn from the exposed surface, both in PBT and PBT-FG.
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Gardette, Jean-Luc. "Photo-ageing of Poly(Butylene Terephthalate) and Poly(Butylene Terephthalate)-Fibre Glass Systems." Polymers and Polymer Composites 5, no. 1 (1997): 7–13. http://dx.doi.org/10.1177/096739119700500102.
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The photolysis and photo-oxidation mechanisms of poly(butylene terephthalate) (PBT) and poly(butylene terephthalate)-fibre glass (PBT-FG) irradiated under polychromatic light (λ ≥ 2300 nm) were studied. Derivatisation reactions coupled to FTIR analysis of the exposed samples permitted the identification of the various photo-products and the proposal of mechanisms. It was found that the same photo-products were formed in PBT and PBT-FG. Micro-FTIR analysis of the irradiated samples showed that the photochemical reactions were limited to a depth of 50 urn from the exposed surface, both in PBT and PBT-FG.
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Tehran, Ata Chalabi, Karim Shelesh-Nezhad, and Farshid Javidi Barazandeh. "Mechanical and thermal properties of TPU-toughened PBT/CNT nanocomposites." Journal of Thermoplastic Composite Materials 32, no. 6 (2018): 815–30. http://dx.doi.org/10.1177/0892705718780198.
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This research studies the properties of poly (butylene terephthalate) (PBT)-based systems toughened with thermoplastic polyurethane (TPU; 10, 20, and 30 wt%) and reinforced with multiwalled carbon nanotubes (CNTs; 0.1, 0.2, and 0.3 wt%). Different compositions prepared via melt mixing. Morphology studies showed good compatibility between the two polymeric phases in PBT/TPU. The addition of TPU to PBT reduced crystallization rate and melt temperature, while inclusion of CNTs had nucleation effect and increased the degree of crystallinity, crystallization, and melt temperatures. The existence of TPU in PBT caused significant enhancement in notch-impact resistant. The inclusion of CNTs to PBT/TPU blend led to the substantial improvements in tensile and flexural strengths and moduli. Dynamic mechanical thermal analysis revealed that the incorporation of CNTs into PBT/TPU enhanced storage modulus and heightened glass transition temperature. The storage modulus of PBT/TPU/CNT nanocomposite containing 0.5 wt% CNT was comparable with that of pure PBT particularly at high temperatures.
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Liu, Jing, Hsiang-Ching Wang, Chean-Cheng Su, and Cheng-Fu Yang. "Chemical Interaction-Induced Evolution of Phase Compatibilization in Blends of Poly(hydroxy ether of bisphenol-A)/Poly(1,4-butylene terephthalate)." Materials 11, no. 9 (2018): 1667. http://dx.doi.org/10.3390/ma11091667.
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An immiscible blend of poly(hydroxy ether of bisphenol-A) (phenoxy) and poly(1,4-butylene terephthalate) (PBT) with phase separation was observed in as-blended samples. The compatibilization of phenoxy/PBT blends can be promoted through chemical exchange reactions of phenoxy with PBT upon annealing. The annealed phenoxy/PBT blends had a homogeneous phase with a single Tg that could be enhanced by annealing at 260 °C. Infrared (IR) spectroscopy demonstrated that phase homogenization could be promoted by annealing the phenoxy/PBT blend, where alcoholytic exchange occurred between the dangling hydroxyl group (–OH) in phenoxy and the carbonyl group (C=O) in PBT in the heated blends. The alcoholysis reaction changed the aromatic linkages to aliphatic linkages in the carbonyl groups, which initially led to the formation of a graft copolymer of phenoxy and PBT with an aliphatic/aliphatic carbonyl link. The progressive alcoholysis reaction resulted in the transformation of the initial homopolymers into block copolymers and finally into random copolymers, which promoted phase compatibilization in blends of phenoxy with PBT. As the amount of copolymers increased upon annealing, the crystallization of PBT was inhibited by alcoholytic exchange in the blends.
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Pham, Thi Hong Nga, Nguyen Phuong Duy Tran, Thien Khiem Tran, et al. "Effect of PC Percentages on Hardness and Notched Impact Strength of PBT/PC Blends." Solid State Phenomena 329 (March 25, 2022): 17–22. http://dx.doi.org/10.4028/p-781ca3.
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Polybutylene terephthalate (PBT) has been proven to be a potential material for modern car bumpers. However, the potential of PBT is limited by its low notched impact strength. The main aim of this study is the improvement in the notched impact strength of PBT by blending with polycarbonate (PC). PBT/PC blend at different ratios (95/5, 90/10, 85/15, 80/20) is investigated in notched Izod impact strength (ASTM D256) and hardness (ASTM D2240). Results are compared to those of neat PBT. It was found that notched Izod impact strength decreased with increasing PC rate in the blend, overall, from 4.35 kJ/m2 of neat PBT to 3.37 kJ/m2 of 80/20 blend. The microstructure of testing samples was observed through FESEM images taken at fracture surfaces to determine the cause of the decrease. The low interfacial adhesion between PBT and PC phases is believed to be the main reason. However, an increase in notched impact strength was shown, from 4.18 kJ/m2 of 95/5 blend to 4,71 kJ/m2 of 90/10 blend. This result is presumed to be due to the compatibilizing effect of PBT-PC copolymers formed during the melt blending process. Hardness testing result demonstrates neither significant improvement nor deterioration. It concluded that it is possible to improve the notched impact strength of PBT by blending with PC. The PBT/10% PC blend is a suitable choice for car bumper material since its notch impact strength is higher than neat PBT.
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Park, Eun-Soo. "Morphology, mechanical, and dielectric breakdown properties of PBT/PET/TPE, PBT/PET/PA66, PBT/PET/LMPE, and PBT/PET/TiO2blends." Polymer Composites 29, no. 10 (2008): 1111–18. http://dx.doi.org/10.1002/pc.20626.
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Longinos, Sotirios Nik, and Mahmut Parlaktuna. "Kinetic analysis of dual impellers on methane hydrate formation." International Journal of Chemical Reactor Engineering 19, no. 2 (2021): 155–65. http://dx.doi.org/10.1515/ijcre-2020-0231.
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Abstract This study investigates the effects of types of impellers and baffles on methane hydrate formation. Induction time, water conversion to hydrates (hydrate yield), hydrate formation rate and hydrate productivity are components that were estimated. The initial hydrate formation rate is generally higher with the use of Ruston turbine (RT) with higher values 28.93 × 10−8 mol/s in RT/RT with full baffle (FB) experiment, but the decline rate of hydrate formation was also high compared to up-pumping pitched blade turbine (PBTU). Power consumption is higher also in RT/RT and PBT/RT with higher value 392,000 W in PBT/RT with no baffle (NB) experiment compared to PBT/PBT and RT/PBT experiments respectively. Induction time values are higher in RT/RT experiments compared to PBT/PBT ones. Hydrate yield is always smaller when there is no baffle in all four groups of experiments while the higher values exist in experiments with full baffle. It should be noticed that PBT is the same with PBTU, since all experiments with mixed flow have upward trending.
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Whitten, Justin, Dawn Tarabochia, Michelle Grocke, and David Graham. "226 The Feasibility and Acceptability of Perturbation-Based Balance to Older Adults in Rural Communities." Journal of Clinical and Translational Science 7, s1 (2023): 69–70. http://dx.doi.org/10.1017/cts.2023.297.
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OBJECTIVES/GOALS: Older adults in rural communities are at an elevated risk of falling. Perturbation-Based Balance Training (PBT) is a highly effective fall prevention paradigm but its feasibility in the community is unknown. The purpose of this study was to determine the feasibility and acceptability of PBT to older adults and local clinicians in rural communities. METHODS/STUDY POPULATION: 19 older adults (60+ years) were recruited from communities in rural Montana to take part in a PBT program. The PBT program was implemented using a bespoke portable PBT treadmill developed by our research team and validated against commercial PBT treadmills. To increase ecological validity, the program was implemented by local clinicians. The PBT program lasted 6 weeks, with 1 session per week, participants received up to 35 trip perturbations per session. The feasibility and acceptability of PBT to participants and clinicians was assessed within the Theoretical Framework of Acceptability, prospectively and retrospectively via interviews and surveys, and concurrently via field notes. RESULTS/ANTICIPATED RESULTS: Data analysis is ongoing and will be complete by the time of presentation. Preliminary results suggest the portable PBT program was generally acceptable to older adults and local clinicians. Perceived effectiveness was generally positive and increased balance awareness and low burden are emerging as common themes. Local clinicians indicated the burden of implementing PBT was low, PBT fit within their views on fall prevention, and had a high level of perceived effectiveness. There appear to be a few limitations to feasibility, which are primarily related to the weight and transportation of the treadmill. We are currently working to refine the treadmill and lower its weight and are developing a grant with local clinicians and extension agents that would facilitate transportation to a broader network of communities. DISCUSSION/SIGNIFICANCE: Our preliminary findings suggest PBT is feasible in rural communities and accepted by older adults. Increased balance and fall awareness and low burden are emerging as important factors in the feasibility and acceptability of PBT. This study provides a foundation for future studies to translate other PBT modalities from the lab to the community.
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Feng, Tianliang, Yangzhou Li, Liang Fang, and Zhenming Chen. "The Impact of Artificial Marble Wastes on Heat Deflection Temperature, Crystallization, and Impact Properties of Polybutylene Terephthalate." Polymers 13, no. 23 (2021): 4242. http://dx.doi.org/10.3390/polym13234242.
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As artificial marble is abundant and widely used in residential and commercial fields, the resource utilization of artificial marble wastes (AMWs) has become extremely important in order to protect the environment. In this paper, polybutylene terephthalate/artificial marble wastes (PBT/AMWs) composites were prepared by melt blending to maximize resource utilization and increase PBT performance. The research results showed that the filling of AMWs was beneficial to the improvement of PBT-related performance. X-ray diffraction analysis results indicated that after filling AMWs into the PBT matrix, the crystal structure of PBT was not changed. Heat deflection temperature (HDT) analysis results indicated that the HDT of PBT composites with 20 wt% AMWs reached 66.68 °C, which was 9.12 °C higher than that of neat PBT. Differential scanning calorimetry analysis results showed that heterogeneous nucleation could be well achieved when the filling content was 15 wt%; impact and scanning electron microscope analysis results showed that due to the partial core-shell structure of the AMWs, the impact strength of PBT was significantly improved after filling. When the filling amount was 20 wt%, the impact strength of the PBT composites reached 23.20 kJ/m2, which was 17.94 kJ/m2 higher than that of neat PBT. This research will not only provide new insights into the efficient and high-value utilization of AMWs, but also provide a good reference for improved applications of other polymers.
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Wilson, Taylor Anne, Joseph I. Kang Jr, Lei Huang, Alexandra Vacaru, Kevin Nogueira Martins, and Warren W. Boling. "Adjuvant proton beam therapy in patients with grade 2 meningiomas." Surgical Neurology International 15 (March 1, 2024): 62. http://dx.doi.org/10.25259/sni_485_2023.
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Background: The World Health Organization (WHO) grade 2 meningiomas behave aggressively with a high proclivity toward recurrence despite maximal surgical resection. Our institution, a pioneer of proton therapy, uses exclusively proton beam radiation, and thus, we present a retrospective cohort analysis of patients with WHO grade 2 meningiomas treated with adjuvant proton beam therapy (PBT) at our institution between 2007 and 2019. The effects of adjuvant PBT were evaluated. Methods: Data collected include diagnosis, gender, histological subtype, WHO grade, the extent of surgical resection, adjuvant PBT radiation, details of the PBT radiation, recurrence, any additional PBT radiation, systemic medical therapy, and disease-specific survival. Results: Among the WHO grade 2 meningiomas (n = 50) recommended PBT, 80% and 78% of patients with gross-total resection (GTR) and subtotal resection (STR), respectively, followed through with PBT. The median radiation dose of PBT was 59.5 Gy and 59.92 Gy for patients with GTR and STR, respectively, with a median of 33 fractions delivered in 1.8 Gy doses for both groups. Combined 3-year progression-free survival (PFS) was 96%, and 5-year PFS was 92%. Combined overall survival was 95% at five years. Minimal radiation side effects were reported with no grade 3 or higher toxicities. Conclusion: Our results suggest that adjuvant PBT is well tolerated with minimal radiation toxicity. Alternative to photon radiation, PBT may be considered at least as safe and effective for adjuvant treatment of WHO grade 2 meningiomas when it is available.
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Афонин, М. Ю., С. Н. Конченко та Т. С. Сухих. "Синтез и конформационные особенности люминесцентного фосфогуанидина с фенилбензотиазольным заместителем". Журнал структурной химии 65, № 7 (2024): 129687. http://dx.doi.org/10.26902/jsc_id129687.
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Разработана трехстадийная схема синтеза (1) Pbt-NH2 + CS2 → (Pbt-NH)2C=S (1, Pbt = 4-(1’,3’-бензотиазол-2’-ил)фенил, (2) 1 + PPh3 + I2 → Pbt-N=C=N-Pbt (2), (3) 2 + Ph2PH → (Pbt-N)(Pbt-NH)CPPh2 (3) нового люминесцентного фосфогуанидина 3, выход которого на последней стадии в отсутствие катализатора оказался уникально высоким (90 %). Причину высокой реакционной способности соединения 2, приводящей к такому выходу, объясняет высокий электростатический потенциал при центральном атоме углерода, что показано с помощью метода теории функционала плотности (DFT). Для соединения 3 получены две полиморфные модификации 3α, 3β и сольватоморф 3γ·ТГФ. Методом рентгеноструктурного анализа на монокристаллах (РСА) установлены структуры 2, 3α, 3β и 3γ·ТГФ. Сопоставлением данных расчета (DFT) изменения энергии молекулы 3 в зависимости от торсионного угла между фенильным и бензотиазольным фрагментами, не превышающей 2 кДж/моль в диапазоне –15 ÷ 30°, объяснена тенденция к существованию разных соответствующих конформаций в кристаллах различных производных фенилбензотиазола. Изучены фотофизические свойства фаз 3β и 3γ·ТГФ, установлено, что они проявляют фотолюминесценцию с максимумом эмиссии при 510 нм.
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Ignaczak, Sobolewski, and El Fray. "Bio-Based PBT–DLA Copolyester as an Alternative Compatibilizer of PP/PBT Blends." Polymers 11, no. 9 (2019): 1421. http://dx.doi.org/10.3390/polym11091421.
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The aim of this work was to assess whether synthesized random copolyester, poly(butylene terephthalate-r-butylene dilinoleate) (PBT–DLA), containing bio-based components, can effectively compatibilize polypropylene/poly(butylene terephthalate) (PP/PBT) blends. For comparison, a commercial petrochemical triblock copolymer, poly(styrene-b-ethylene/butylene-b-styrene) (SEBS) was used. The chemical structure and block distribution of PBT–DLA was determined using nuclear magnetic resonance spectroscopy and gel permeation chromatography. PP/PBT blends with different mass ratios were prepared via twin-screw extrusion with 5 wt% of each compatibilizer. Thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis were used to assess changes in phase structure of PP/PBT blends. Static tensile testing demonstrated marked improvement in elongation at break, to ~18% and ~21% for PBT–DLA and SEBS, respectively. Importantly, the morphology of PP/PBT blends compatibilized with PBT–DLA copolymer showed that it is able to act as interphase modifier, being preferentially located at the interface. Therefore, we conclude that by using polycondensation and monomers from renewable resources, it is possible to obtain copolymers that efficiently modify blend miscibility, offering an alternative to widely used, rubber-like petrochemical styrene compatibilizers.
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Brehme, Sven, Thomas Köppl, Bernhard Schartel, and Volker Altstädt. "Competition in aluminium phosphinate-based halogen-free flame retardancy of poly(butylene terephthalate) and its glass-fibre composites." e-Polymers 14, no. 3 (2014): 193–208. http://dx.doi.org/10.1515/epoly-2014-0029.
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AbstractAluminium diethylphosphinate (AlPi-Et) and inorganic aluminium phosphinate with resorcinol-bis(di-2,6-xylyl phosphate) (AlPi-H+RXP) were compared with each other as commercially available halogen-free flame retardants in poly(butylene terephthalate) (PBT) as well as in glass-fibre-reinforced PBT (PBT/GF). Pyrolysis behaviour and flame retardancy performance are reported in detail. AlPi-H+RXP released phosphine at very low temperatures, which can become a problem during processing. AlPi-Et provided better limiting oxygen index (LOI) values and UL 94 ratings for bulk and PBT/GF than AlPi-H+RXP. Both flame retardants acted via three different flame-retardancy mechanisms in bulk as well as in PBT/GF, namely, flame inhibition, increased amount of char, and a protection effect of the char. AlPi-Et was more efficient in decreasing the total heat evolved of PBT in the cone calorimeter test. AlPi-H+RXP reduced the peak heat release rate of PBT more efficiently than AlPi-Et. An optimum loading of AlPi-Et in PBT/GF was found, which was below the supplier’s recommendation. This loading provides a maximum increase in LOI and a maximum decrease in total heat evolved.
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Tran, Ngoc-Thien, and Nga Thi-Hong Pham. "Investigation of the Effect of Polycarbonate Rate on Mechanical Properties of Polybutylene Terephthalate/Polycarbonate Blends." International Journal of Polymer Science 2021 (August 14, 2021): 1–7. http://dx.doi.org/10.1155/2021/7635048.
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Polybutylene terephthalate (PBT) is a brittle polymer with the disadvantage of low impact toughness, so it is not easy to meet the requirements of both high tensile strength, flexural strength, and high impact strength. In this study, PBT/polycarbonate (PC) blends at different ratios of 95/5, 90/10, 85/15, and 80/20 are investigated. Tensile strength, flexural strength, and unnotched Izod impact strength are studied according to the ASTM D638, ASTM D790, and ASTM D256 standards. The results show that tensile strength, which increased with increasing PC content, is 53.00, 62.34, 60.59, 62.98, and 64.46 MPa for 0, 5, 10, 15, and 20% PC samples. Flexural strength and elastic flexural testing of PBT/PC blends are higher than neat PBT. In addition, the unnotched Izod impact strength of PBT/PC is also higher than PBT. However, when PC content increases, impact strength tends to decrease. Impact strength is 44.82, 80.46, 68.82, 50.45, and 48.05 kJ/m2 corresponds to 0, 5, 10, 15, and 20% PC, in which 5% PC sample is twice as high as the impact strength of PBT. Microstructure of the blends has shown that PC has become dispersed phase in PBT matrix. The size and quantity of dispersed PC particles increase with increasing PC rate in the blend. Thus, when adding PC, PBT/PC all meet the requirements of high tensile strength, flexural strength, and high impact strength. The PBT/5% PC model gives the highest impact strength while still ensuring durability, which potential application for making car door handles.
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Loughan, Ashlee, Sarah Braun, Mariya Husain, Farah Aslanzadeh, Rachel Boutte, and Autumn Lanoye. "QOLP-06. EXISTENTIAL DISTRESS: UNADDRESSED CONCERNS FOR ADULT NEURO-ONCOLOGY PATIENTS." Neuro-Oncology 21, Supplement_6 (2019): vi198. http://dx.doi.org/10.1093/neuonc/noz175.826.
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Abstract BACKGROUND Primary brain tumor (PBT) patients may experience existential distress including fear of cancer recurrence and death anxiety; however, to date few have examined this issue. The objectives of this study were twofold: first, to systematically review PBT representation in the psycho-oncology literature on existential distress, and second, to preliminarily assess the prevalence and correlates of existential distress in a sample of PBT patients. PRIMARY OBJECTIVE METHODS/ RESULTS Three databases (PsycINFO, PubMed, and CINAHL) were systematically searched to identify articles measuring fear of cancer recurrence, fear of dying, or death anxiety in oncology patients. Included studies were examined to determine the frequency of PBT patients and identify exclusion criteria relevant to neuro-oncology. For studies including PBT patients, a more thorough data extraction was undertaken. Systematic searching found 336 studies meeting inclusion criteria (N=133,027). Eight studies (0.16% of the participants) included PBT patients. Exclusion criteria such as cognitive impairment and specific treatment parameters may have prohibited PBT patient participation. Studies including PBT patients used mixed methods with limited demographic analyses; existential distress was correlated with heightened psychological distress and poor quality of life. SECONDARY OBJECTIVE METHODS/ RESULTS A cross-sectional analysis of 81 PBT patients (20–86 years old) was conducted. Patients completed validated questionnaires of death anxiety, death distress, generalized anxiety, and depressive symptoms. Descriptive analyses, t-tests, chi-square, and Pearson correlations were conducted. Up to 79% of PBT patients endorsed death anxiety. These patients were significantly younger, more likely to be female, and have a low-grade brain tumor (p< 0.05). Significant correlations were found between death anxiety and distress and symptoms of anxiety and depression (p< 0.01). CONCLUSIONS PBT patients are underrepresented in existential psycho-oncology literature, despite preliminary findings suggesting prevalence of these concerns. Future investigations of existential distress in neuro-oncology is warranted to inform psychosocial screening and treatment for PBT patients.
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Odei, Bismarck C. L., Dustin Boothe, Sameer R. Keole, et al. "A 20-Year Analysis of Clinical Trials Involving Proton Beam Therapy." International Journal of Particle Therapy 3, no. 3 (2016): 398–406. http://dx.doi.org/10.14338/ijpt-d-16-00030.1.
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Purpose: Clinical trials (CTs) in proton beam therapy (PBT) are important for determining its benefits relative to other treatments. An analysis of PBT trials is, thus, warranted to understand the current state of PBT CTs and the factors affecting current and future trials. Materials and Methods: We queried the clinicaltrials.gov Website using the search terms: proton beam therapy, proton radiation, and protons. A total of 152 PBT CTs were identified. We used χ2 analysis and logistic regression to evaluate trial characteristics. Results: Most CTs were recruiting (n = 79; 52.0%), phase II (n = 95; 62.5%), open label (n = 134; 88.2%), single-group assignment (n = 84; 55.3%), and with primary treatment endpoints of safety and efficacy (n = 94; 61.8%). The primary treatment sites included gastrointestinal (n = 32; 21.1%), central nervous system (n = 31; 20.4%), lung (n = 21; 13.8%), prostate (n = 19; 12.5%), sarcoma (n = 15; 9.9%), and others (n = 24; 15.8%). Comparison studies between radiation modalities involved PBT and intensity-modulated photon therapy (n = 11; 7.2%), PBT and general photon therapy (n = 8; 5.3%), and PBT and carbon-ion therapy (n = 7; 4.6%). The PBT CTs underwent substantial growth after 2008 but now appear to be in decline. Nongovernmental institutions, comprising university centers, hospital systems, and research groups, have funded the greatest number of CTs (n= 106; 69.7%). The National Institutes of Health (NIH) were more likely to fund CTs involving the central nervous system ( P = 0.02). Trials involving NIH funding were more likely to result in successful trial completion ( P = 0.02). Conclusion: Among PBT CTs, most were phase II trials, with a very few being phase III CTs. Funding of PBT CTs originating from industry or the NIH is limited. Recently, there has been a declining trajectory of newly initiated PBT trials. It is not yet clear whether this represents a true trend or just a pause in CT implementation. Despite multiple impediments to PBT CTs, the particle therapy community continues to work toward evidence generation.
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Xu, J. M., S. C. Ng, and H. S. O. Chan. "Preliminary study on alternating thienylene/phenylene copolymers functionalized with an electron-donating or -withdrawing group." Journal of Materials Research 16, no. 5 (2001): 1235–37. http://dx.doi.org/10.1557/jmr.2001.0171.
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Three novel regioregular polymers substituted with electron-donating or -withdrawing groups, poly[1,4-bis(3-X-2,5-thienylene)phenylene-alt-2,5-dioctyl-1,4-phenylene] [PBT(X), X = OMe, H, CN], were synthesized and characterized. They are highly fluorescent, but the absorption wavelength of PBT(CN) and PBT(OMe) are shifted toward the blue and red regions, respectively, with reference to PBT(H). The onset reduction potential of PBT(CN) is –1.11 V versus SCE (saturated calomel electrode), which is higher than that of the cyano derivative of poly(phenylene vinylene), indicating it be a good candidate as electron transport layer. The onset oxidation and reduction potentials of PBT(OMe) (0.96 and –1.28 V versus SCE respectively) suggest it would perform well as emissive layer in light-emitting display applications.
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Kwiatkowska, Magdalena, Inez Kowalczyk, Zbigniew Rozwadowski, Elżbieta Piesowicz, and Anna Szymczyk. "Hytrel-like Copolymers Based on Furan Polyester: The Effect of Poly(Butylene Furanoate) Segment on Microstructure and Mechanical/Elastic Performance." Molecules 28, no. 7 (2023): 2962. http://dx.doi.org/10.3390/molecules28072962.
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This paper aims to compare the performance of two Hytrel-like segmented copolymers: “classic” PBT-b-PTMG and fully bio-based PBF-b-PTMG, containing poly(butylene furanoate) as the rigid segment. The idea behind this research is to assess whether the sustainable copolymers can successfully replace those “classic” once at the thermoplastic elastomers’ market. Two series of copolymers were synthesized under the same process parameters, had the same compositions, but differed in aromatic ring structure in terephthalate/furanoate unit. Furthermore, the materials were processed by injection moulding as typical Hytrel products. Then, the samples were subjected to extensive characterisation including NMR, GPC, FTIR, DSC, WAXS, DMTA, TGA techniques and mechanical tests with particular interest in the microstructure formed during processing and its effect on the copolymers’ mechanical and elastic behaviour. The detailed analysis proved that PBF-b-PTMG and PBT-b-PTMG copolymers represent two kinds of materials with similar chemical structure, some features of thermoplastic elastomers, but evident differences in their physical properties.
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Ma, Meng, Lei Niu, Jinming Ma, Jiqiang Ma, and Tifeng Jiao. "Fabrication and Thermal Degradation Kinetics of PBT/BEO/Nano-Sb2O3 Composites." Journal of Nanomaterials 2020 (December 26, 2020): 1–10. http://dx.doi.org/10.1155/2020/6641702.
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Developing polybutylene terephthalate (PBT) with high thermal stability and flame-retardant properties is crucial for automotive, biomedical devices, electronics, and other fields. Herein, we focus on a PBT/brominated epoxy resin (BEO)/nano-Sb2O3 composites by a melt-blending method. The effects of heating rate and nano-Sb2O3 content on the thermal stability and thermal degradation kinetics of PBT composites were studied by TG-DSC. With the increasing of heating rate, the thermal hysteresis effect of temperature gradient is produced, which is eliminated when the temperature exceeds 400°C. With the increase of nano-Sb2O3 content, the E a of PBT/BEO/nano-Sb2O3 composites increases at first and then decreases. When the content of nano-Sb2O3 is 3 wt%, the E a of PBT/BEO/nano-Sb2O3 is the highest, which is 66.18 kJ/mol (31.43%) higher than that of neat PBT. Also, the exploration of the thermal degradation kinetics of PBT/BEO/nano-Sb2O3 composites is expected to provide research ideas for new high flame-retardant materials.
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Zhang, Duo You, Peng Liu, Chun Fa Ouyoung, et al. "Influence of PNA012 on Crystallization and Mechanical Properties of Polybutylene Terephthalate." Advanced Materials Research 624 (December 2012): 264–68. http://dx.doi.org/10.4028/www.scientific.net/amr.624.264.
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PNA012 is a new nucleating agent on polybutylene terephthalate. The effect of different dosage of PNA012 on crystallization and mechanical properties were investigated by means of differential scanning calorimetry, universal testing machine, melt flow indexer and vicat softening testing machine. It was revealed that the PNA012 could substantially accelerate the crystallization of PBT. Compared with the pure PBT,the crystallization temperature of PBT/PNA012 rises from 196.3 °C to 199.7 °C and crystallization degree from 34.2% to 39.9%. The tensile Strength of PBT/PNA012 is increased 9.7%. The Bending Strength has a rise of 9.3% and the heat distortion temperatures of PBT/PNA012 is increased from 115.07°C to 125.94°C.
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Lin, Steven H., Kaiping Liao, Xiudong Lei, et al. "Health Care Resource Utilization for Esophageal Cancer Using Proton versus Photon Radiation Therapy." International Journal of Particle Therapy 9, no. 1 (2022): 18–27. http://dx.doi.org/10.14338/ijpt-22-00001.1.
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Abstract Purpose In patients treated with chemoradiation for esophageal cancer (EC), randomized trial data demonstrate that proton beam therapy (PBT) reduces toxicities and postoperative complications (POCs) compared with intensity-modulated radiation therapy (IMRT). However, whether radiation therapy modality affects postoperative health care resource utilization remains unknown. Materials and Methods We examined 287 patients with EC who received chemoradiation (prescribed 50.4 Gy/GyE) followed by esophagectomy, including a real-world observational cohort of 237 consecutive patients treated from 2007 to 2013 with PBT (n = 81) versus IMRT (n = 156); and an independent, contemporary comparison cohort of 50 patients from a randomized trial treated from 2012 to 2019 with PBT (n = 21) versus IMRT (n = 29). Postoperative complications were abstracted from medical records. Health care charges were obtained from institutional claims and adjusted for inflation (2021 dollars). Charge differences (Δ = $PBT − $IMRT) were compared by treatment using adjusted generalized linear models with the gamma distribution. Results Baseline PBT versus IMRT characteristics were not significantly different. In the observational cohort, during the neoadjuvant chemoradiation phase, health care charges were higher for PBT versus IMRT (Δ = +$71,959; 95% confidence interval [CI], $62,274–$82,138; P &lt; .001). There was no difference in surgical charges (Δ = −$2234; 95% CI, −$6003 to $1695; P = .26). However, during postoperative hospitalization following esophagectomy, health care charges were lower for PBT versus IMRT (Δ = −$25,115; 95% CI, −$37,625 to −$9776; P = .003). In the comparison cohort, findings were analogous: Charges were higher for PBT versus IMRT during chemoradiation (Δ = +$61,818; 95% CI, $49,435–$75,069; P &lt; .001), not different for surgery (Δ = −$4784; 95% CI, −$6439 to $3487; P = .25), and lower for PBT postoperatively (Δ = −$27,048; 95% CI, −$41,974 to −$5300; P = .02). Lower postoperative charges for PBT were especially seen among patients with any POCs in the contemporary comparison (Δ = −$176,448; 95% CI, −$209,782 to −$78,813; P = .02). Conclusion Higher up-front chemoradiation resource utilization for PBT in patients with EC was partially offset postoperatively, moderated by reduction in POC risks. Results extend existing clinical evidence of toxicity reduction with PBT.
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Corkum, Mark Thomas, Wei Liu, David A. Palma, et al. "Online advertising and marketing claims by providers of proton beam therapy: Are they guideline based?" Journal of Clinical Oncology 37, no. 15_suppl (2019): 6599. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.6599.
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6599 Background: Proton beam therapy (PBT) is a radiotherapy platform that purports an improved therapeutic ratio by way of a rapid radiation dose fall-off. Despite this technology being hindered by significant capital and patient costs, the number of centres offering PBT is increasing exponentially. Consensus guidelines support PBT use in a limited number of disease sites or on clinical trials. As patients frequently obtain information about PBT from hospital or cancer centre websites, the purpose of this study was to evaluate direct to consumer advertising (DTCA) content and claims made by proton therapy centre (PTC) websites. Methods: English PTC websites worldwide were identified using the Particle Therapy Co-Operative Group website. Data abstraction of website content was performed independently by two investigators. Eight international guidelines were consulted to determine indications for PBT. Univariate and multivariate logistic regression models were used to identify website characteristics that were associated with a higher likelihood to make non-evidence-based claims of PBT such as improved disease control or cure. Results: From the 48 PTCs with 46 English websites, most (58%) did not provide any references for claims made regarding PBT. These included: improved disease control or cure (61%), fewer side effects (85%), or was the standard of care (13%). Prostate (87%), head and neck (87%) and pediatric (83%) cancers were the most frequently listed PBT-indicated disease sites, consistent with international guidelines. However, pancreatobiliary (52%), breast (50%) and esophageal (44%) cancers were frequently advertised despite not being endorsed in any consensus guidelines. On multivariate analysis, an increasing number of listed disease sites and claims of being a regional PTC leader were associated with indicating that PBT offers greater disease control or cure. The availability of PBT through a clinical trial was mentioned on 57% of websites. Conclusions: PTC websites often contain information and DTCA claims inconsistent with international consensus guidelines. As online marketing information may have significant influence on patient decision-making, alignment of such information with accepted guidelines and consensus opinion should be adopted by PBT providers.
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Petrova, G. N., and E. Ya Beider. "The Effect of Modifying Polybutylene Terephthalate on its Processability and Mechanical Properties." International Polymer Science and Technology 44, no. 9 (2017): 15–22. http://dx.doi.org/10.1177/0307174x1704400904.
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The effect of a modifying additive – a polybutylenetetramethylene oxide (PBT-PTMO) block copolymer of grade V-1000 – on the processability and mechanical properties of polybutylene terephthalate (PBT) was investigated. It was shown that the mixing of the thermoplastic elastomer – the block copolymer of grade V-1000 – with the rigid, hard, but relatively brittle structural material PBT makes it possible to produce materials with a high level of properties. The modification of PBT with the block copolymer leads to an increase in its impact strength without any perceptible loss in tensile strength. Furthermore, the addition of a small amount of block copolymer to PBT improves its processability. The developed PBT composite with the optimum content of modifying additive and fireproofing agent is recommended for the manufacture of moulded articles of decorative-structural designation, and also for the partial replacement of polyamides PA-12L and PA-610L.
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Whitten, Justin, David Graham, Michelle Grocke, Bryant O’Leary, Julie Riley, and Dawn Tarabochia. "THE FEASIBILITY AND ACCEPTABILITY OF PERTURBATION BALANCE TRAINING IN RURAL COMMUNITIES: A MIXED METHODS STUDY." Innovation in Aging 7, Supplement_1 (2023): 598. http://dx.doi.org/10.1093/geroni/igad104.1956.
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Abstract Falls are a leading cause of morbidity and mortality in older adults. Older adults in rural communities have an elevated risk of falling. Perturbation-Based Balance Training (PBT) is an effective fall-prevention paradigm. However, it’s acceptability and feasibility in community settings is unknown. The purpose of this study was to evaluate the acceptability and feasibility of a community-based PBT program to local community-dwelling older adults and practitioners. Nineteen healthy older adults (60+ years) completed a 6-week PBT program, implemented in conjunction with three community practitioners. Measures of balance, balance confidence and fear of falling were assessed before and after training. Feasibility and acceptability were assessed prospectively, concurrently, and retrospectively via field notes, surveys, and interviews within the Theoretical Framework of Acceptability. PBT was perceived as effective by older adults. Perceived increases in balance awareness, low burden/opportunity-cost and enjoyment of novel training were identified as facilitators. Notably, participants with poor balance tended to perceive PBT as less acceptable and demonstrated apprehensive and avoidant behavior, reinforcing the importance of comprehensive screening prior to participation in PBT. Practitioners perceived PBT as acceptable, with efficacy, low burden/opportunity-cost, and ethicality being primary facilitators. While the portable nature of the perturbation treadmill increased feasibility in rural communities, cost of equipment and transportation were perceived as substantial barriers to implementation. These results suggest PBT is acceptable in rural communities and demonstrate a need for training modalities that are more feasibly implemented in a community setting. Further investigation of low-tech alternatives such as manual PBT may offer potential solutions.
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Katagiri, Katsunori, Kiyoto Shiga, Daisuke Saito, et al. "Particle Beam Therapy and Surgery as Radical Treatments for Parotid Malignancies—A Single-Center Preliminary Case Study." Journal of Clinical Medicine 13, no. 11 (2024): 3314. http://dx.doi.org/10.3390/jcm13113314.
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Background/Objectives: Particle beam therapy (PBT) was approved in April 2018 for head and neck malignancies and has since been introduced as a radical therapy for parotid malignancies. However, its prevalence and effectiveness in relation to surgical treatment have not been investigated. Methods: In this study, we evaluated 36 patients with parotid malignancy who underwent surgery (n = 26) or PBT (n = 10) and then analyzed the annual changes in the number of patients, survival rates, and clinical factors affecting prognosis. Results: Of the ten patients who opted for PBT, two and eight patients underwent PBT before and after 2018, respectively. There was a significant difference between these two groups of patients (p = 0.04). Of the ten patients who underwent PBT, five patients were recurrent cases; meanwhile, all twenty-six patients who underwent surgery were receiving initial treatment. Only one patient in each group had local recurrence after the treatment. Conclusions: The use of PBT as a radical therapy for parotid malignancies has been increasing since 2018, and patients with recurrent tumors tended to choose PBT. The outcome of the patients who underwent PBT did not seem to be inferior compared with those of the patients who underwent surgery. The histopathological type was a crucial issue in the outcomes of patients who underwent radical therapy for parotid malignancies.
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Kostajnšek, Klara, Krste Dimitrovski, Hüseyin Kadoğlu, et al. "Functionalization of Woven Fabrics with PBT Yarns." Polymers 13, no. 2 (2021): 260. http://dx.doi.org/10.3390/polym13020260.
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Elasticity and recovery are important for clothing comfort, especially in the manufacture of apparel and sportswear. Recently, yarns containing PBT (polybutylene terephthalate), which are able to develop good elastic properties with high recovery after a finishing process (e.g., thermal treatment), have been used for this purpose. The aim of this work is to give a comprehensive overview of the use of PBT yarns in woven structure, with the aim of improving the elastic properties of cotton-like fabrics. The experimental part was divided into three main sequences to investigate the fabric properties (physical, elastic, UPF, comfort) influenced by (1) PBT-containing yarn structure, (2) weave and fabric structure (basic weaves and complex weaves) with PBT in weft direction, and (3) processing sequence—thermal treatment of PBT yarns or fabrics after weaving. According to the results, PBT-containing yarns have great potential for the production of lightweight elastic fabrics. The advantages of improving the elastic properties of fabrics by incorporating a relatively small amount of PBT yarns into the fabric only in certain areas, thereby minimally affecting the production costs, are demonstrated by a product with partially elastic areas obtained after thermal treatment.
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Zhu, Jie, Yue Ming Zhang, Zhi Cheng Tao, Nan Wei Xu, Li Qun Wang, and Xiao Lin Zhu. "The Preparation of Silk Fibroin Modified PBT-co-PBS/PEG Composite Films and their Effects on Clinical Human Salivary Epithelial Cells Transplantation." Journal of Biomimetics, Biomaterials and Tissue Engineering 18 (December 2013): 29–42. http://dx.doi.org/10.4028/www.scientific.net/jbbte.18.29.
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We reported the preparation of surface modified poly(butylene terephthalate)-co-poly(butylene succinate)-b-poly(ethylene glycol) (i.e. PBT-co-PBS/PEG) films by three methods: silk fibroin coating, SO2 plasma treatment and silk fibroin anchoring. The obtained composite films were named SF/(PBT-co-PBS/PEG), SO2/(PBT-co-PBS/PEG) and SF/SO2/(PBT-co-PBS/PEG), respectively. Their surface properties were characterized by contact angles, surface energies and XPS. The biocompatibility of the films were further evaluated by the morphology, attachment, proliferation and viability of human salivary epithelial cells (HSG cells). Results revealed that SF/SO2/(PBT-co-PBS/PEG) possessed the high surface free energy (59.67 mJ/m2) and could immobilize a great amount of fibroin (SF surface coverage: 26.39 wt%), which attributed to the formation of such polar groups as hydrosulfide group, sulfonic group, carboxyl and carbonyl ones in the process of SO2 plasma treatment. The cell tests suggested that the silk fibroin anchoring could significantly enhance the biocompatibility of PBT-co-PBS/PEG, which implied the potential application of fibroin modified PBT-co-PBS/PEG for clinical HSG cells transplantation in artificial salivary gland constructs.
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Lee, D. S., J. K. Doo, B. Kim, and J. Kim. "Structure-Property Relationships of Poly(Butylene Terephthalate)/Polyolefin Blends." Journal of Polymer Engineering 18, no. 1-2 (1998): 17–30. http://dx.doi.org/10.1515/polyeng-1998-1-204.
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Abstract Structure-property relationships of poly(butylene terephthalate) (PBT) / polyolefin (PO) (80/20) blends modified by a reactive compatibilizer, ethylene-acrylic ester-glycidyl methacrylate terpolymer (BAG), were investigated as part of studies on toughening of PBT. POs used for the study were ethylene propylene rubber (EPR), low-density polyethylene (LDPE), and high-density polyethylene (HDPE), whose deformabilities were different at room temperature. It was observed that the particle size of PO in the discrete phase was the smallest when the EAG content was 8~12 wL%. Shear viscosity of the blends increased as the particle size was decreased. It seems that the morphology and rheological properties of the blends were affected by graft copolymers formed in situ from EAG and PBT during melt mixing. Brittle-tough transition of impact strength of the PBT/EPR/EAG blends was observed when the EAG content was increased from 0 to 4 wt% at room temperature. However, blends of PBT/LDPE/EAG and PBT/HDPE/EAG showed brittle-tough transition with increasing the EAG content from 8 wt% to 12 wt%. It is postulated that toughening of the PBT depends on the deformability of the discrete PO particle as well as its size.
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Jinxin, He, Guo Yang, Sun Shulin, and Zhang Huixuan. "Influence of methyl methacrylate-co-glycidyl methacrylate copolymers on the compatibility, morphology and mechanical properties of poly(butylene terephthalate) and polycarbonate blends." Journal of Polymer Engineering 35, no. 3 (2015): 247–56. http://dx.doi.org/10.1515/polyeng-2014-0200.
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Abstract Methyl methacrylate-co-glycidyl methacrylate copolymers (MMA-co-GMA) were prepared to compatibilize the poly(butylene terephthalate) (PBT) and polycarbonate (PC) blends. The chemical reactions between the PBT and the epoxy groups and the good miscibility between the PC and the poly(methyl methacrylate) (PMMA) phase were responsible for the excellent compatibilization effect of the MMA-co-GMA copolymers. The MMA-co-GMA copolymers decreased the melting and crystallization temperature of the PBT phase in the PBT/PC blends. Dynamic mechanical analysis result showed that the exchange reactions were inhibited due to the compatibilization reactions owing to the consumption of the carboxyl/hydroxyl end groups of the PBT phase. MMA-co-GMA copolymers decreased the phase domain size of the PBT/PC blends, and with the increase in GMA content in the MMA-co-GMA copolymers, the blends changed from a double continuous phase to a single continuous phase structure. Tensile test indicated that the yield stress, elongation at break and elastic modulus of the PBT/PC blends increased due to the addition of MMA-co-GMA. The impact strength of the blends changed unnoticeably.
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Tsochatzis, Emmanouil D., Joao Alberto Lopes, Margaret V. Holland, Fabiano Reniero, Hendrik Emons, and Claude Guillou. "Isolation, Characterization and Structural Elucidation of Polybutylene Terephthalate Cyclic Oligomers and Purity Assessment using a 1H qNMR Method." Polymers 11, no. 3 (2019): 464. http://dx.doi.org/10.3390/polym11030464.
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The use of polybutylene terephthalate (PBT) as a food contact material is increasing over the last years. Typical contaminations in the final PBT product include its cyclic oligomers, which are allowed as additives in food contact plastics according to Regulation (EU) No. 10/2011.Their investigation is currently limited by the lack of analytical standards and physical-chemical information. Therefore, four PBT cyclic oligomers have been isolated and purified from a PBT raw material with an automated preparative HPLC-DAD system. Comprehensive characterization of the compounds was performed using Ultra-High Performance Liquid Chromatography (UHPLC) with high resolution time-of-flight mass spectrometry, Fourier-Transform Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Nuclear Magnetic Resonance (NMR) spectroscopy. The purity of each oligomer was assessed using a 1H qNMR method and ranged from 96.1% to 97.0% for PBT tetramer and trimer respectively. The availability of pure and well characterized PBT cyclic oligomer standards will facilitate future studies of release from plastic food packaging materials.
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Ferreira, Vera Christina Camargo de Siqueira, Elba Cristina Sá de Camargo Etchebehere, José Luiz Barbosa Bevilacqua, and Nestor de Barros. "Suspicious amorphous microcalcifications detected on full-field digital mammography: correlation with histopathology." Radiologia Brasileira 51, no. 2 (2018): 87–94. http://dx.doi.org/10.1590/0100-3984.2017.0025.
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Abstract Objective: To evaluate suspicious amorphous calcifications diagnosed on full-field digital mammography (FFDM) and establish correlations with histopathology findings. Materials and Methods: This was a retrospective study of 78 suspicious amorphous calcifications (all classified as BI-RADS® 4) detected on FFDM. Vacuum-assisted breast biopsy (VABB) was performed. The histopathological classification of VABB core samples was as follows: pB2 (benign); pB3 (uncertain malignant potential); pB4 (suspicion of malignancy); and pB5 (malignant). Treatment was recommended for pB5 lesions. To rule out malignancy, surgical excision was recommended for pB3 and pB4 lesions. Patients not submitted to surgery were followed for at least 6 months. Results: Among the 78 amorphous calcifications evaluated, the histopathological analysis indicated that 8 (10.3%) were malignant/suspicious (6 classified as pB5 and 2 classified as pB4) and 36 (46.2%) were benign (classified as pB2). The remaining 34 lesions (43.6%) were classified as pB3: 33.3% were precursor lesions (atypical ductal hyperplasia, lobular neoplasia, or flat epithelial atypia) and 10.3% were high-risk lesions. For the pB3 lesions, the underestimation rate was zero. Conclusion: The diagnosis of precursor lesions (excluding atypical ductal hyperplasia, which can be pB4 depending on the severity and extent of the lesion) should not necessarily be considered indicative of underestimation of malignancy. Suspicious amorphous calcifications correlated more often with precursor lesions than with malignant lesions, at a ratio of 3:1.