Incorporation of germanium in zeolites is well known to confer static flexibility to their framework, by stabilizing the formation of small rings. In this work, we show that the flexibility ...associated to Ge atoms in zeolites goes beyond this static effect, manifesting also a clear dynamic nature, in the sense that it leads to enhanced molecular diffusion. Our study combines experimental and theoretical methods providing evidence for this effect, which has not been described previously, as well as a rationalization for it, based on atomistic grounds. We have used both pure‐silica and silico‐germanate ITQ‐29 (LTA topology) zeolites as a case study. Based on our simulations, we identify the flexibility associated to the pore breathing‐like behavior induced by the Ge atoms, as the key factor leading to the enhanced diffusion observed experimentally in Ge‐containing zeolites.
Ge force: Incorporation of germanium in zeolites is well known to confer static flexibility to their framework by stabilizing the formation of small rings. In this work, it is shown that this flexibility goes beyond this static effect, and also manifests a clear dynamic nature (see figure), in the sense that the higher window flexibility leads to enhanced molecular diffusion.
Zeolite stability, in terms of lattice energy, is revisited from a crystal-chemistry point of view. A linearized equation relates the zeolite lattice energy using simple structural data readily ...available from experiments or modeling. The equation holds for a large range of zeolite energies, up to 3 eV per tetrahedron with respect to quartz, and has been validated internally via two simple machine learning automatic procedures for data fitting/reference partitions and externally using data from recently synthesized zeolites. The approach is certain in locating those recently synthesized zeolites in the energy range of those experimentally known zeolites used in the parametrization of the linearized equation. Hidden intrinsic structural data–energy correlations were found for data sets built from energy-relaxed structures along with energy values computed using the same energy functions employed in the structural relaxation. The asymmetry of the structural features is relevant for an accurate description of the energy.
HPM‐16 is a highly porous germanosilicate zeolite with an interrupted framework that contains a three‐dimensional system of 12+10×10(12)×12+10‐membered ring (MR) pores. The 10(12) MR pore in the b ...direction is a 10 MR pore with long 12 MR stretches forming 30 Å long tubular supercages. Along one direction the 10 MR pores are fused, meaning that the separation between adjacent pores consists of a single tetrahedron that is, additionally, connected to only three additional tetrahedra (a Q3). These fused pores are thus decorated by T‐OH groups along the whole diffusion path, creating a hydrophilic region embedded in an otherwise essentially hydrophobic environment. The structure is built from highly porous 12×12×12 MR uninterrupted layers that are connected to each other through Q3 producing a second system of 10×10×10 MR pores. This zeolite can be extensively degermanated yielding a material with high thermal stability, despite its interrupted nature.
HPM‐16 is a new interrupted zeolite with 3D intersecting 12+10×10(12)×12+10 MR channels containing 30 Å long supercages. The structure, with a very long b‐axis (>50 Å), was solved by state‐of‐the‐art 3D electron diffraction. Degermanated HPM‐16 is stable up to 800 °C. Several derived structures were studied, including a recently reported one.
Due to the very rapid development of technology as well as the increased demand of quality food, vegetables and fruits are more under spotlights for enhancing their healthy characteristics. With the ...involvement of new mathematical methods and updated variety of scientific investigations in food science, the need for better characterization of agricultural products arises. This review covers the bioimpedance method used for electrical characterization of fruits and vegetables, known as the bioimpedance spectroscopy. This electrical advantageous method offers an ecological agricultural production. By evaluating the quality factors of horticultural products, bioimpedance targets a double sustainable plan: an environmental friendly food control and an improved consumer's health care at once. An objective interpretation of the quality factors importance in the horticultural sector is presented along with a wide definition of bioimpedance spectroscopy. Moreover, the paper highlights techniques used for the bioimpedance properties measurements since their initiations. The collective data is tabulated for the destructive, non-destructive bioimpedance where clear objectives and focused conclusions of each measurement method are displayed. This paper summarizes the various findings and conclusions of these experiments seeking better oriented investigation in the future and encouraging further quality food applications in areas where data is still ambiguous. Non-destructive bioimpedance techniques open new perspectives for cleaner quality control system in industrial applications for fruit and vegetables quality determination.
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•The quality of vegetables and fruits are important for the future of agriculture.•The electrical characteristics of vegetables and fruits can help to quality determination.•Bioimpedance methods used for electrical characterization of fruits and vegetables are reviewed.•Non-destructive bioimpedance applications are tabulated.•An overview of bioimpedance sensor technology is done.
The filling fraction limit (FFL) of skutterudites, that is, the complex balance of formation enthalpies among different species, is an intricate but crucial parameter for achieving high ...thermoelectric performance. In this work, we synthesized a series of Ybx Co4 Sb12 samples with x=0.2-0.6 and systemically studied the FFL of Yb, which is still debated even though this system has been extensively investigated for decades. Our combined experimental efforts of X-ray diffraction, microstructural and quantitative compositional analyses clearly reveal a Yb FFL of ~0.29 in CoSb3 , which is consistent with previous theoretical calculations. The excess Yb in samples with x>0.35 mainly form metallic YbSb2 precipitates, significantly raising the Fermi level and thus increasing the electrical conductivity and decreasing the Seebeck coefficient. This result is further corroborated by the numerical calculations based on the Bergman's composite theory, which accurately reproduces the transport properties of the x>0.35 samples based on nominal Yb0.35 Co4 Sb12 and YbSb2 composites. A maximum ZT of 1.5 at 850 K is achieved for Yb0.3 Co4 Sb12 , which is the highest value for a single-element-filled CoSb3 . The high ZT originates from the high-power factor (in excess of 50 μW cm-K-2 ) and low lattice thermal conductivity (well below 1.0 W m-K-1 ). More importantly, the large average ZTs, for example, ~1.05 for 300-850 K and ~1.27 for 500-850 K, are comparable to the best values for n-type skutterudites. The high thermoelectric and thermomechanical performances and the relatively low air and moisture sensitivities of Yb make Yb-filled CoSb3 , a promising candidate for large-scale power generation applications.
Considering the effect of CO2 emission together with the depletion of fossil fuel resources on future generations, industries in particular the transportation sector are in deep need of a viable ...solution to follow the environmental regulation to limit the CO2 emission. Thermoelectrics may be a practical choice for recovering the waste heat, provided their conversion energy can be improved. Here, the high temperature thermoelectric properties of high purity Bi doped Mg2(Si,Sn) are presented. The samples Mg2Si1–x–ySn x Bi y with x(Sn) ≥ 0.6 and y(Bi) ≥ 0.03 exhibited electrical conductivities and Seebeck coefficients of approximately 1000 Ω–1 cm–1 and −200 μV K–1 at 773 K, respectively, attributable to a combination of band convergence and microstructure engineering through ball mill processing. In addition to the high electrical conductivity and Seebeck coefficient, the thermal conductivity of the solid solutions reached values below 2.5 W m–1 K–1 due to highly efficient phonon scattering from mass fluctuation and grain boundary effects. These properties combined for zT values of 1.4 at 773 K with an average zT of 0.9 between 400 and 773 K. The transport properties were both highly reproducible across several measurement systems and were stable with thermal cycling.
Proteolysis-targeting chimeras (PROTACs) are molecules that selectively degrade a protein of interest (POI). The incorporation of ligands that recruit mouse double minute 2 (MDM2) into PROTACs, ...forming the so-called MDM2-based PROTACs, has shown promise in cancer treatment due to its dual mechanism of action: a PROTAC that recruits MDM2 prevents its binding to p53, resulting not only in the degradation of POI but also in the increase of intracellular levels of the p53 suppressor, with the activation of a whole set of biological processes, such as cell cycle arrest or apoptosis. In addition, these PROTACs, in certain cases, allow for the degradation of the target, with nanomolar potency, in a rapid and sustained manner over time, with less susceptibility to the development of resistance and tolerance, without causing changes in protein expression, and with selectivity to the target, including the respective isoforms or mutations, and to the cell type, overcoming some limitations associated with the use of inhibitors for the same therapeutic target. Therefore, the aim of this review is to analyze and discuss the characteristics of MDM2-based PROTACs developed for the degradation of oncogenic proteins and to understand what potential they have as future anticancer drugs.
The 2018 ISDE achalasia guidelines Zaninotto, G; Bennett, C; Boeckxstaens, G ...
Diseases of the esophagus,
2018-Sep-01, 2018-09-01, 20180901, Letnik:
31, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Achalasia is a relatively rare primary motor esophageal disorder, characterized by absence of relaxations of the lower esophageal sphincter and of peristalsis along the esophageal body. As a result, ...patients typically present with dysphagia, regurgitation and occasionally chest pain, pulmonary complication and malnutrition. New diagnostic methodologies and therapeutic techniques have been recently added to the armamentarium for treating achalasia. With the aim to offer clinicians and patients an up-to-date framework for making informed decisions on the management of this disease, the International Society for Diseases of the Esophagus Guidelines proposed and endorsed the Esophageal Achalasia Guidelines (I-GOAL). The guidelines were prepared according the Appraisal of Guidelines for Research and Evaluation (AGREE-REX) tool, accredited for guideline production by NICE UK. A systematic literature search was performed and the quality of evidence and the strength of recommendations were graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Given the relative rarity of this disease and the paucity of high-level evidence in the literature, this process was integrated with a three-step process of anonymous voting on each statement (DELPHI). Only statements with an approval rate >80% were accepted in the guidelines. Fifty-one experts from 11 countries and 3 representatives from patient support associations participated to the preparations of the guidelines. These guidelines deal specifically with the following achalasia issues: Diagnostic workup, Definition of the disease, Severity of presentation, Medical treatment, Botulinum Toxin injection, Pneumatic dilatation, POEM, Other endoscopic treatments, Laparoscopic myotomy, Definition of recurrence, Follow up and risk of cancer, Management of end stage achalasia, Treatment options for failure, Achalasia in children, Achalasia secondary to Chagas' disease.
Objective
To demonstrate that delayed cord clamping (DCC) is safe in mothers with confirmed SARS‐CoV‐2 infection.
Design, setting and participants
Prospective observational study involving ...epidemiological information from 403 pregnant women with SARS‐CoV‐2 between 1 March and 31 May 2020. Data were collected from 70 centres that participate in the Spanish Registry of COVID‐19.
Methods
Patients' information was collected from their medical chart.
Main outcomes and measures
The rate of perinatal transmission of SARS‐CoV‐2 and development of the infection in neonates within 14 days postpartum.
Results
The early cord clamping (ECC) group consisted of 231 infants (57.3%) and the DCC group consisted of 172 infants (42.7%). Five positive newborns (1.7% of total tests performed) were identified with the nasopharyngeal PCR tests performed in the first 12 hours postpartum, two from the ECC group (1.7%) and three from the DCC group (3.6%). No significant differences between groups were found regarding neonatal tests for SARS‐CoV‐2. No confirmed cases of vertical transmission were detected. The percentage of mothers who made skin‐to‐skin contact within the first 24 hours after delivery was significantly higher in the DCC group (84.3% versus 45.9%). Breastfeeding in the immediate postpartum period was also significantly higher in the DCC group (77.3% versus 50.2%).
Conclusions
The results of our study show no differences in perinatal outcomes when performing ECC or DCC, and skin‐to‐skin contact, or breastfeeding.
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This study demonstrates that delayed cord clamping is safe in mothers with confirmed SARS‐CoV‐2 infection.
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This study demonstrates that delayed cord clamping is safe in mothers with confirmed SARS‐CoV‐2 infection.
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