Sonocrystallisation of ZIF-8 in water with high excess of ligand: Effects of frequency, power and sonication time

A systematic study on the sonocrystallisation of ZIF-8 (zeolitic imidazolate framework-8) in a water-based system was investigated under different mixing speeds, ultrasound frequencies, calorimetric powers and sonication time. Regardless of the synthesis technique, pure crystals of ZIF-8 with high BET (Brunauer, Emmett and Teller) specific surface area (SSA) can be obtained in water after only 5 s. Furthermore, 5 s sonication produced even smaller crystals (~0.08 µm). The type of technique applied for producing the ZIF-8 crystals did not have any significant impact on crystallinity, purity and yield. Crystal morphology and size were affected by the use of ultrasound and mixing, obtaining nanoparticles with a more spherical shape than in silent condition (no ultrasound and mixing). However, no specific trends were observed with varying frequency, calorimetric power and mixing speed. Ultrasound and mixing may have an effect on the nucleation step, causing the fast production of nucleation centres. Furthermore, the BET SSA increased with increasing mixing speed. With ultrasound, the BET SSA is between the values obtained under silent condition and with mixing. A competition between micromixing and shockwaves has been proposed when sonication is used for ZIF-8 production. The former increases the BET SSA, while the latter could be responsible for porosity damage, causing a decrease of the surface area. © 2021 The Author(s

Treatment-responsive pudendal dysfunction in chronic inflammatory demyelinating polyneuropathy.

Contains fulltext : 52470.pdf (publisher's version ) (Open Access

Citizenship and gender: theoretical approaches and historical legacies

Recently, citizenship has become a popular concept in different countries. This article explores the reasons why citizenship has become such a 'catch-all' concept, and analyses the relation between gender and citizen ship. Throughout history, we distinguish three vocabularies of citizenship: civic-republican, liberal and communitarian. As we show, they each have advantages and disadvantages from a gender perspective, some of which crop up in current debates on citizenship, as the brief cross-national analysis of the other articles in this issue shows. © 1998 Critical Social Policy 56

Finding Optimal Pairs of Patterns

We consider the problem of finding the optimal pair of string patterns for discriminating between two sets of strings, i.e. finding the pair of patterns that is best with respect to some appropriate scoring function that gives higher scores to pattern pairs which occur more in the strings of one set, but less in the other. We present an O(N²) time algorithm for finding the optimal pair of substring patterns, where N is the total length of the strings. The algorithm looks for all possible Boolean combination of the patterns, e.g. patterns of the form p ∧ ¬q, which indicates that the pattern pair is considered to match a given string s, if p occurs in s, AND q does NOT occur in s. The same algorithm can be applied to a variant of the problem where we are given a single set of sequences along with a numeric attribute assigned to each sequence, and the problem is to find the optimal pattern pair whose occurrence in the sequences is correlated with this numeric attribute. An e#cient implementation based on suffix arrays is presented, and the algorithm is applied to several nucleotide sequence datasets of moderate size, combined with microarray gene expression data, aiming to find regulatory elements that cooperate, complement, or compete with each other in enhancing and/or silencing certain genomic functions