•Glass joint performance is defined by pre- and post-breakage strength and stiffness.•In adhesive joints, full cohesive failure inside the adhesive layer is desirable.•Weathering conditions may ...deteriorate adhesive and laminated joints.•In the long term, pre-compressed joints may be affected by stress relaxation.•The most common breakage cause in bolted joints is glass fracture at the borehole.
In order to increase transparency in buildings, structural elements made of laminated glass are being developed. The recent technological improvements in terms of material research, fabrication processes, and construction techniques, are creating new design opportunities for laminated glass structural elements. For laminated glass, the post-breakage strength and safety are important because of the brittle nature of glass, especially in structural applications. The connection between elements is a critical part, because high loads are concentrated in small surfaces, leading to local peak stresses. In this review, different connection types for structural glass elements are presented, and their performance is evaluated. Most common connection types are mechanical, adhesive, and laminated. The main goal of this review is to compare the experimental results obtained from different types of connections, evaluating the type of test, the materials used, the pre- and post-breakage performance, the failure mode, and the influence of ageing factors and load duration.
•Steel slag as aggregate in concrete for high temperature TES.•Concrete mixtures thermally cycled from 290 to 700 °C.•OPC and CAC with steel slag preserve integrity after thermal cycling.•Concrete ...with steel slag revealed promising specific heat capacity.•Thermal conductivity and compressive strength need further improvement.
Thermal energy storage represents a crucial element to increase solar power dispatchability. Within sensible heat storage in solid media, concrete is considered a low-cost alternative to be further developed and therefore, this has been addressed in this paper. Four concrete dosages were designed, combining each type of considered cement, ordinary Portland and calcium aluminate cement, with each type of considered aggregate, silico-calcareous and a steel slag. Thermo-mechanical properties of concrete were studied before and after 10 thermal cycles from 290 °C to 700 °C. Maximum operating temperature and heating rates were selected accordingly to the targeted application, a concentrating solar power (CSP) tower plant. At macro-level, results show thermal cycle stability of concrete with steel slag aggregate in both cement types. On the contrary, at micro-level, the petrography analysis shows the lack of bonding between steel slag aggregate and the cement paste. In contrast, concrete mixtures containing silico-calcareous aggregates collapse after thermal cycling.
Concrete is identified in the literature as a suitable material for thermal energy storage applications, with even innovative application potentials such as storage media in concentrating solar power ...plants. To ensure a suitable heat transfer among concrete components, the binder material of concrete (cement paste) require further research and understanding to this aim. In particular, the thermal stability of cement paste under temperature cycled conditions arises as a research gap. In this study, ordinary Portland and calcium aluminate cement types were selected using a low water-cement ratio. Thermo-mechanical properties were studied before and after 1, 10, and 25 or 50 thermal cycles at 200 °C, 400 °C, 600 °C, and 800 °C. Although ordinary Portland cement paste showed micro-cracking propagation after 25 thermal cycles from ambient temperature to 200 °C and 400 °C, both cement pastes preserved their integrity, being compressive strength higher in ordinary Portland cement. On the contrary, after 25 or 50 thermal cycles at 600 °C and 800 °C, only calcium aluminate cement preserved its integrity, while ordinary Portland cement revealed a fragmentation status. Despite the compressive strength decrease in calcium aluminate paste at 600 °C and 800 °C, as a result of porosity increase, the properties were maintained after 10 thermal cycles. However, thermal conductivity in calcium aluminate paste was reduced nearly 50% after the first cycle at temperatures higher than 200 °C.
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•Thermo-mechanical stability of OPC and CAC paste at high temperature.•Calcium aluminate cement paste withstand 50 cycles at 800 °C.•OPC paste has higher compressive strength after 10 cycles at 200 °C and 400 °C.•20% of porosity increase in CAC paste after 50 thermal cycles at 800 °C.•Thermal conductivity is half reduced after thermal cycles at 800 °C.
•A tensile test was performed on seven laminated glass interlayer materials.•The mechanical properties of the materials were affected by the elongation rate.•EVALAM, EVASAFE and TPU were the least ...affected by ageing factors.•Water immersion led to water absorption and transparency loss for SentryGlas and PVB.•Mechanical properties of SentryGlas and PVB dropped after water immersion.
Laminated glass is obtained by bonding two or more glass layers with a polymeric interlayer. The coupling between glass layers depends on the shear stiffness of the interlayer. The mechanical and optical properties of the interlayer may be affected by weathering factors. Since interlayer materials are viscoelastic, the strain rate may also affect its stiffness and ultimate strength. In this paper, tensile tests are conducted on seven different polymeric films (PVB BG-R20, PVB DG-41, PVB ES, SentryGlas, EVASAFE, EVALAM 80, and TPU) at three different strain rates. The mechanical and optical properties of unaged specimens are compared with specimens exposed to thermal cycles, high temperatures, and moisture. The unaged specimens of PVB DG-41, PVB ES, and SentryGlas had the highest stiffness, EVALAM 80 and EVASAFE had the highest ductility, PVB and SentryGlas had the highest tensile strength, and EVALAM 80, EVASAFE, and TPU were less affected by ageing factors and strain rate.
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•Laminated glass double-lap shear specimens with four interlayers were tested.•The type of interlayer material affected the maximum load and breakage mode.•Humidity and long-term UV ...radiation had a negative effect on some specimens.•The strength either increased or remained unaffected by thermal cycles.•The stress distribution was not homogeneous in the glass-interlayer interface.
Laminated glass is a composite laminate obtained from combining two or more glass layers with a polymeric interlayer. The adhesion between glass and interlayer, as well as the shear strength and stiffness of the interlayer, are key factors to evaluate the cohesive behaviour of laminated glass. Glass is a very durable material, while polymeric interlayers can be deteriorated by exposure to weathering factors. A double-lap shear test was carried out on laminated glass specimens, with four different interlayer materials (PVB BG-R20, Saflex DG-41, SentryGlas, and EVASAFE), after different ageing tests (unaged, thermal cycles, humidity, and UV radiation). The material selection affected the shear behaviour of the bond between glass and interlayer, and so did the previous exposure to certain ageing factors. Since the polymeric interlayers are viscoelastic materials, and therefore its mechanical properties are time- and temperature-dependant, the results here presented should be complemented with dynamic and static tests at different temperatures.
Colorectal cancer (CRC) is one of the most common types of cancer worldwide. The KRAS mutation is present in 30–50% of CRC patients. This mutation confers resistance to treatment with anti-EGFR ...therapy. This article aims at proving that computer tomography (CT)-based radiomics can predict the KRAS mutation in CRC patients. The piece is a retrospective study with 56 CRC patients from the Hospital of Santiago de Compostela, Spain. All patients had a confirmatory pathological analysis of the KRAS status. Radiomics features were obtained using an abdominal contrast enhancement CT (CECT) before applying any treatments. We used several classifiers, including AdaBoost, neural network, decision tree, support vector machine, and random forest, to predict the presence or absence of KRAS mutation. The most reliable prediction was achieved using the AdaBoost ensemble on clinical patient data, with a kappa and accuracy of 53.7% and 76.8%, respectively. The sensitivity and specificity were 73.3% and 80.8%. Using texture descriptors, the best accuracy and kappa were 73.2% and 46%, respectively, with sensitivity and specificity of 76.7% and 69.2%, also showing a correlation between texture patterns on CT images and KRAS mutation. Radiomics could help manage CRC patients, and in the future, it could have a crucial role in diagnosing CRC patients ahead of invasive methods.
Laminated glass beams without metallic or polymeric reinforcements generally lack post-breakage strength and ductility. This paper aims to perform a comparative study by testing five different fully ...transparent laminated glass beam designs in order to see how parameters such as the number and thickness of glass sheets (3 x 10 mm or 5 x 6 mm), the interlayer material (PVB Clear or SentryGlas), and the thermal treatment of glass (annealed or heat-strengthened) affect the pre-breakage performance and post-breakage safety. A buckling analysis is also performed using a numerical model with ABAQUS CAE. The study includes a comparison between the results of different experimental mechanical tests on laminated glass beams, including the tests presented in this paper, as well as other tests found in the literature. All designs presented a linear elastic behaviour until initial breakage. The interlayer material mainly affected the crack shape of laminated glass beams. Beams with five sheets of annealed glass had a more progressive breakage, and therefore a safer behaviour, than beams with three sheets of annealed or heat-strengthened glass.
Aims
To analyse the non‐glycosylated protein fraction from Melipona beecheii honey for antimicrobial activity against Escherichia coli O157:H7.
Methods and Results
The proteins from M. beecheii honey ...were separated according to their degree of glycosylation using Concanavalin A‐affinity chromatography. The total protein extract and its fractions were analysed by 1D and 2D electrophoresis. We also determined the antimicrobial and antihaemolytic activities of the total protein extract and the non‐glycosylated fraction. Furthermore, we evaluated the effect of this non‐glycosylated fraction for the expression of the Stx1, Stx2, EAE and HlyA pathogen genes. Melipona beecheii honey contained at least 24 proteins with molecular weights ranging between 7·6 and 95 kDa and isoelectric points between 3 and 10, three proteins from the 24 are non‐glycosylated. The non‐glycosylated fraction had an MIC90 of 1·128 µg ml−1, and this fraction inhibited the haemolytic activity of the pathogen, as well as reduced the expression of Stx1, Stx2 and HlyA. The MbF1‐2 protein from the non‐glycosylated fraction was sequenced and identified as a homologue of the royal jelly‐like protein of Melipona quadrifasciata.
Conclusions
The non‐glycosylated protein fraction from M. beecheii honey greatly contributes to antibacterial activity and it is composed of at least three proteins, of which MbF1‐2 provided over 50% of the antimicrobial activity.
Significance and Impact of the Study
The study showed significant antimicrobial activity from several proteins present in the honey of M. beecheii. Interestingly, the non‐glycosylated protein fraction demonstrated antihaemolytic activity and adversely affected the expression of virulence genes in Escherichia coli O157:H7; these proteins have the potential to be used in developing therapeutic agents against this bacterium.
Heterotrophic microalgae are recognized as a source of bioactive compounds. However, there are still some drawbacks for their use at an industrial scale associated with the high cost of glucose, the ...main carbon source in heterotrophic cultures. In recent years, significant efforts have been made to investigate more sustainable carbon sources to produce biomass. In this study, the capacity of Schizochytrium limacinum to grow on waste-derived volatile fatty acids and the effect that their use produces on biomass and fatty acids profiles were investigated. Acetic, propionic, butyric, valeric and caproic acid were evaluated independently, as well as in a synthetic mixture (VFA). The use of acetic and butyric resulted in a good biomass productivity, while the use of valeric and propionic acid resulted in higher content of odd-chain fatty acids (OCFA), increasingly investigated due to their potential benefits for human health. The use of industrial waste-derived VFA as a potential carbon source was validated through the utilization of biowaste derived effluents from a volatile fatty acid platform. The biomass produced was of 18.5 g/L, 54.0% lipids, 46.3% docosahexaenoic acid (DHA) and 25.0% OCFA, concluding that waste derived VFA can produce DHA and OCFA in a suitable ratio of DHA/OCFA with potential industrial applications.
La pandemia de COVID-19 va a conllevar cambios en la asistencia neurológica, que no se pueden prever fácilmente a largo plazo.
A través de un modelo de informadores clave se busca el consenso de cómo ...va a ser la especialidad en un plazo de 5 años, siendo los encuestados jefes de servicio de neurología con conocimiento amplio de la situación al haber actuado durante la pandemia.
Aunque se obtiene un grado de acuerdo bajo entre los encuestados, sí se describen acuerdos por consenso a nivel mayor (85%) y menor (70%). Los principales acuerdos se refieren al incremento de precauciones, al uso de la telemedicina, al mantenimiento de las consultas telefónicas, a la reducción de asistencia a las consultas evitando que hayan salas de espera con un número alto de personas, al desarrollo de técnicas docentes no presenciales y a la adaptación en el desarrollo de ensayos clínicos en relación con la visita de los monitores. Sin embargo, no se acuerda que haya cambios en la indicación de exploraciones complementarias, ni en la propia exploración neurológica.
El método de informadores clave ha permitido conocer qué cambios se pueden prever tras la pandemia.
The COVID-19 pandemic will give rise to long-term changes in neurological care, which are not easily predictable.
A key informant survey was used to enquire about the changes expected in the specialty over the next 5 years. The survey was completed by heads of neurology departments with broad knowledge of the situation, having been active during the pandemic.
Despite a low level of consensus between participants, there was strong (85%) and moderate consensus (70%) about certain subjects, mainly the increase in precautions to be taken, the use of telemedicine and teleconsultations, the reduction of care provided in in-person consultations to avoid the presence of large numbers of people in waiting rooms, the development of remote training solutions, and the changes in monitoring visits during clinical trials. There was consensus that there would be no changes to the indication of complementary testing or neurological examination.
The key informant survey identified the foreseeable changes in neurological care after the pandemic.
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