A note on the stability of Toeplitz matrix inversion formulas

AbstractIn this paper, we consider the stability of the algorithms emerging from Toeplitz matrix inversion formulas. We show that if the Toeplitz matrix is nonsingular and well-conditioned, then they are numerically forward stable

1,1′-Methyl­enedipyridinium dichloride monohydrate

In the crystal structure of the title salt, C11H12N2 2+·2Cl−·H2O, the dication adopts a butterfly shape [dihedral angle between rings = 69.0 (1)°] with the water mol­ecule lying in the V-shaped cavity. Each O—H bond of the water molecule lies parallel to an aromatic ring and forms an O—H⋯Cl inter­action to a chloride anion. The methyl­ene C atom in the dication and the water O atoms lie on special positions of twofold site symmetry

Diaqua­bis­(5-carb­oxy-2-ethyl-1H-imidazole-4-carboxyl­ato-κ2 N 3,O 4)cobalt(II) trihydrate

In the title compound, [Co(C7H7N2O4)2(H2O)2]·3H2O, the CoII cation, located on an inversion center, is N,O-chelated by two 5-carboxy-2-ethyl-1H-imidazole-4-carboxylate anions and further coordinated by two water mol­ecules in a distorted octa­hedral geometry. Only one carboxy group of the anion is deprotonated, and the two carboxyl groups of the same anion are linked via an intra­molecular O—H⋯O hydrogen bond. One of the lattice water mol­ecules is located on an inversion center, its H atom equally disordered over two positions. One of H atoms of another lattice water mol­ecules is also equally disordered over two sites. Water H atoms and the amino H atom all are involved in an inter­molecular hydrogen-bonded network in the crystal

Size-selective purification of hepatitis B virus-like particle in flow-through chromatography: types of ion exchange adsorbent and grafted polymer architecture

Hepatitis B virus-like particles expressed in Escherichia coli were purified using anion exchange adsorbents grafted with polymer poly(oligo(ethylene glycol) methacrylate) in flow-through chromatography mode. The virus-like particles were selectively excluded, while the relatively smaller sized host cell proteins were absorbed. The exclusion of virus-like particles was governed by the accessibility of binding sites (the size of adsorbents and the charge of grafted dextran chains) as well as the architecture (branch-chain length) of the grafted polymer. The branch-chain length of grafted polymer was altered by changing the type of monomers used. The larger adsorbent (90 μm) had an approximately twofold increase in the flow-through recovery, as compared to the smaller adsorbent (30 μm). Generally, polymer-grafted adsorbents improved the exclusion of the virus-like particles. Overall, the middle branch-chain length polymer grafted on larger adsorbent showed optimal performance at 92% flow-through recovery with a purification factor of 1.53. A comparative study between the adsorbent with dextran grafts and the polymer-grafted adsorbent showed that a better exclusion of virus-like particles was achieved with the absorbent grafted with inert polymer. The grafted polymer was also shown to reduce strong interaction between binding sites and virus-like particles, which preserved the particles' structure

Using online multiple choice questions with multiple attempts: A case for self-directed learning among tertiary students

Criticisms on multiple choice questions (MCQs) include the possibility of students answering MCQs correctly by guessing, and MCQs generally are said to fall short in cultivating independent learning skills, such as taking charge of their learning goals. Countering these common concerns, this research used online MCQ exercises with multiple attempts to investigate the experiences that drove students to become self-directed learners. In this research, 60 students completed two sets of online MCQ exercises with multiple attempts outside of classroom time for six weeks consecutively. Both focus group interviews and an online survey were conducted to investigate the experiences of using online MCQ exercise with multiple attempts in relation to the development of self-directed learning (SDL). The findings of the study showed that the criticisms may be unfounded. Data leads to the conclusion that the majority of the students do not just try to guess at the correct answers. Rather, many of them attempted the online MCQ exercises more than once to improve themselves indicating that they were interested in self-learning. Students also reported that they utilised search and inquiry skills that clearly showed motivated initiatives to plan how to overcome their weaknesses by independently looking for relevant resources, determine their own learning goals, and evaluate their own learning performance as a firm indicator of SDL development. Based on the findings, this study is able to refute the claim that MCQs are unable to cultivate independent learning skills

An IoT-Based Framework of Webvr Visualization for Medical Big Data in Connected Health

Recently, telemedicine has been widely applied in remote diagnosis, treatment and counseling, where the Internet of Things (IoT) technology plays an important role. In the process of telemedicine, data are collected from remote medical equipment, such as CT machine and MRI machine, and then transmitted and reconstructed locally in three-dimensions. Due to the large amount of data to be transmitted in the reconstructed model and the small storage capacity, data need to be compressed progressively before transmission. On this basis, we proposed a lightweight progressive transmission algorithm based on large data visualization in telemedicine to improve transmission efficiency and achieve lossless transmission of original data. Moreover, a novel four-layer system architecture based on IoT has been introduced, including the sensing layer, analysis layer, network layer and application layer. In this way, the three-dimensional reconstructed data at the local end is compressed and transmitted to the remote end, and then visualized at the remote end to show reconstructed 3D models. Thus, it is conducive to doctors in remote real-time diagnosis and treatment, and then realize the data processing and transmission between doctors, patients and medical equipment

Elevated activated partial thromboplastin time-based clot waveform analysis markers have strong positive association with acute venous thromboembolism

Introduction: A hypercoagulable state is a predisposition for venous thromboembolism (VTE). The activated partial thromboplastin time (aPTT)-based clot waveform analysis (CWA) is a global haemostatic measure but its role in assessment of hypercoagulability and thrombotic disorders is uncertain. We aimed to study the changes of CWA parameters in acute VTE. We hypothesized that patients with acute VTE would demonstrate higher CWA values than control patients without VTE and having elevated CWA parameters is associated with acute VTE. Materials and methods: Clot waveform analysis data from patients (N = 45) with objectively proven acute VTE who had an aPTT performed prior to initiation of anticoagulation were compared with controls (N = 111). The CWA parameters measured were min1, min2, max2 and delta change. Results: While the mean aPTT between VTE patients and controls did not differ (P = 0.830), the mean CWA parameters were significantly higher among VTE patients than controls (min1, P < 0.001; min2, P = 0.001; max2, P = 0.002; delta change, P < 0.001). There were significantly more cases within the VTE group exhibiting CWA values above their reference intervals than the control group (all P < 0.001), with the odds ratios for VTE of 8.0, 5.2, 4.8 and 18.6 for min1, min2, max2 and delta change, respectively (all P < 0.001). Conclusions: Patients with acute VTE had elevated aPTT-based CWA parameters than controls. Higher CWA parameters were significantly associated with acute VTE