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In paper degradation studies, the viscosity-average degree of polymerisation (DPv) is often used as a key indicator of the extent of degradation of cellulosic paper. DPvcan be deduced from the viscosity of dilute paper solutions, as typically measured through glass capillary viscometry. The current study proposes an efficient, alternative method to evaluate DPvof cellulosic paper, which is based on rotational rheometry. The proposed methodology relies on the application of a shear flow in a thin film of cellulose solution to measure its dynamic viscosity, from which DPvcan be subsequently derived in a straightforward fashion. Rheometry allows to measure the viscosity for a range of shear rates, which results in multiple DPvevaluations per sample, and thus in statistically representative data from an individual test. Further, rheometry typically requires considerably less paper mass per test than glass capillary viscometry, which makes the method attractive for paper degradation studies with limited sample availability. Also, rheometry measurements are less work-intensive than glass capillary viscometry measurements. The rheometry method has been applied to 4 hygrothermally aged cellulose paper samples and the unaged counterpart. The measurement results regarding the age-dependency of DPvand the number of cellulose chain scissions are compared to those obtained by glass capillary viscometry, showing a very good agreement. At a longer ageing time, both experimental methods reveal a non-linear decrease in time of DPv, and a non-linear increase in time of the number of cellulose chain scissions, which indicate that the cellulose ageing process is realistically captured. The agreement in measurement results further demonstrates that rheometry is an easy-to-use, accurate and efficient alternative for DPvmeasurements by glass capillary viscometry.

This paper details the main factors influencing the performance of limestone calcined clay cements (LC3). The kaolinite content plays a major role in the rheological properties as well as strength development. Even in the presence of secondary phases, kaolinite can be accurately quantified by thermogravimetric analysis. The performance of LC3is slightly influenced by the calcination process of clay, but it can be optimized by using the correct calcination temperature and applying a specific mix design with adjusted sulfate and alkali content. The hydration reactions of LC3are fully characterized. They vary slightly from plain cement. There is no significant change in terms of phase assemblage. The main properties of LC3are also described. LC3blends show a lower creep compliance and a delay in shrinkage strains compared with plain cement. Concerning durability, LC3blends show outstanding performance with respect to resisting chloride ingress and expansion from the alkali–silica reaction.

Colloidal quantum dot (CQD) solar cells combine solution-processability with quantum-size-effect tunability for low-cost harvesting of the sun’s broad visible and infrared spectrum. The highest-performing colloidal quantum dot solar cells have, to date, relied on a depleted-heterojunction architecture in which an n-type transparent metal oxide such as TiO2induces a depletion region in the p-type CQD solid. These devices have, until now, been limited by a modest depletion region depth produced in the CQD solid owing to limitations in the doping available in TiO2. Herein we report a new device geometryone based on a donor–supply electrode (DSE)that leads to record-performing CQD photovoltaic devices. Only by employing this new charge-extracting approach do we deepen the depletion region in the CQD solid and thereby extract notably more photocarriers, the key element in achieving record photocurrent and device performance. With the use of optoelectronic modeling corroborated by experiment, we develop the guidelines for building a superior CQD solar cell based on the DSE concept. We confirm that using a shallow-work-function terminal electrode is essential to producing improved charge extraction and enhanced performance.

We report on a comprehensive investigation of radiation characteristics of THz emitters using structures based on the Sierpinski fractal. Self-similarity present in the geometrical properties of these antennas improves the coupling of emitted radiation to free space. Using THz-TDS it is shown that these novel antennas produce higher radiation power when compared to the bow-tie antenna. To the best of our knowledge this is the first time that Sierpinski fractal antennas have been used as emitters for generating THz radiation.

The mmu-miR-290-295 cluster codes for a family of microRNAs (miRNAs) that are expressed de novoduring early embryogenesis and are specific for mouse embryonic stem cells (ESC) and embryonic carcinoma cells (ECC). Detailed sequence analysis and alignment studies of miR-290-295 precursors demonstrated that the cluster has evolved by repeated duplication events of the ancient miR-290 precursor. We show that under serum starvation, overexpression of miR-290-295 miRNAs withhold ES cells from early differentiation, ensures their high proliferation rate and capacity for forming alkaline phosphate positive colonies. Transcriptome analysis revealed that differentiation related marker genes are underexpressed upon high miR-290-295 level. Importantly, miR-290-295 overexpression prevents ES cells from accumulation in G1 phase at low serum level, and seems to regulate cell cycle in different phases. Our data underline that miR-290-295 miRNAs contribute to the natural absence of G1 checkpoint in embryonic stem cells. We define the cell cycle regulators Wee1 and Fbxl5 as potential direct targets of miR-290-295 miRNAs in vitro. Our results suggest that miR-290-295 miRNAs exhibit their effect predominantly through the regulation of cell cycle phase distribution.