Correlation between EEG spectral power and cerebral perfusion in patients with acute ischemic stroke.

Dry electrode electroencephalography (EEG) has the potential to diagnose ischemic stroke in the acute phase. In the current study we determined the correlation between EEG spectral power and ischemic stroke size and location as determined by computed tomography perfusion (CTP). Dry electrode EEG recordings were performed in patients with acute ischemic stroke in the emergency room. CTP preceded the EEG recordings as part of standard imaging protocol. Infarct core volume, total hypoperfused volume and local cerebral blood flow (CBF) were estimated with CTP. Additionally, global and local EEG spectral power were determined. We used Spearman's correlation coefficients to evaluate the correlation between variables. We included 27 patients (median age 72 [IQR:69-80] years, 15/27 [56%] men). Median CTP-to-EEG time was 32 (range:8-138) minutes. Hypoperfused volumes were estimated for 12/27 (44%) patients. Infarct core volume correlated best with global delta power (ρ = 0.76, p < 0.01), total hypoperfused volume with global alpha power (ρ = -0.58, p = 0.05), and local CBF with local alpha power (ρ = 0.43, p < 0.01). We conclude that dry electrode EEG signals slow down with increasing hypoperfused volume, which could potentially be used to discriminate between small and large ischemic strokes.

High performance clean versus artifact dry electrode EEG data classification using Convolutional Neural Network transfer learning.

Objective: Convolutional Neural Networks (CNNs) are promising for artifact detection in electroencephalography (EEG) data, but require large amounts of data. Despite increasing use of dry electrodes for EEG data acquisition, dry electrode EEG datasets are sparse. We aim to develop an algorithm for clean versus artifact dry electrode EEG data classification using transfer learning. Methods: Dry electrode EEG data were acquired in 13 subjects while physiological and technical artifacts were induced. Data were per 2-second segment labeled as clean or artifact and split in an 80% train and 20% test set. With the train set, we fine-tuned a pre-trained CNN for clean versus artifact wet electrode EEG data classification using 3-fold cross validation. The three fine-tuned CNNs were combined in one final clean versus artifact classification algorithm, in which the majority vote was used for classification. We calculated accuracy, F1-score, precision, and recall of the pre-trained CNN and fine-tuned algorithm when applied to unseen test data. Results: The algorithm was trained on 0.40 million and tested on 0.17 million overlapping EEG segments. The pre-trained CNN had a test accuracy of 65.6%. The fine-tuned clean versus artifact classification algorithm had an improved test accuracy of 90.7%, F1-score of 90.2%, precision of 89.1% and recall of 91.2%. Conclusions: Despite a relatively small dry electrode EEG dataset, transfer learning enabled development of a high performing CNN-based algorithm for clean versus artifact classification. Significance: Development of CNNs for classification of dry electrode EEG data is challenging as dry electrode EEG datasets are sparse. Here, we show that transfer learning can be used to overcome this problem.

Short report: A co-designed psychoeducation for older autistic adults-a multiple case study.

LAY ABSTRACT: After receiving an autism diagnosis by a clinician, psychoeducation (i.e. information regarding autism) is often offered. However, older autistic adults (55+ years) may need specific information about the challenges they face in daily life as they are in a specific life phase. A psychoeducation program for this specific age group does not exist yet. We first developed such a program together with autistic adults and clinicians working with autistic people, after which we tested the program with nine autistic adults (56-73 years) and someone close to them (so-called proxy). Before testing the program, we determined together with autistic older adults what they thought should be the outcome of this intervention in order to state whether it was, indeed, a useful intervention. Earlier studies found that autistic people often think differently about their own autistic characteristics than their proxy. A reduction of this difference could increase mutual understanding. Therefore, the main hypothesis was that the program would decrease this difference with respect to autistic characteristics and cognitive challenges (e.g. memory problems). Another hypothesis was that the program would have a positive impact on a series of other factors, such as self-esteem. The results showed that the program did neither decrease the difference in insight nor the other tested factors. Nonetheless, we believe it is important to keep on working on a psychoeducation program for older autistic adults, because participants informed us the program had still helped them in certain ways and they gave helpful feedback for improvements of the program.

Immediate implant placement: the fate of the buccal crest. A retrospective cone beam computed tomography study.

This retrospective study aimed to analyse the fate of the buccal crest after immediate implant placement (IIP) through the use of cone beam computed tomography (CBCT). In 16 consecutive patients, an implant was placed in a more palatal position after extraction, thereby creating a gap of at least 2mm between the implant and the buccal crest. Subsequently, this gap was filled with a bone substitute. Preoperatively, immediate postoperatively, and late postoperatively, a CBCT was made to measure the thickness of the buccal crest. After application of the bone substitute, the buccal crest increased in thickness from 0.9mm to 2.4mm (mean). At a mean of 103 weeks after IIP, late postoperative CBCT scans showed that the thickness of the buccal crest was compacted to 1.8mm. In the same period, the height of the buccal crest increased by 1.6mm (mean) to, on average, 1.2mm above the implant shoulder. The aesthetic outcome was analysed using the White and Pink Esthetic Score (WES and PES). Both scored high: 8.4 and 11.8, respectively. Within the limitations of this study, the results of this IIP protocol are promising. Long-term prospective research on this topic on a large number of patients is necessary.

[Immediately placed front tooth implants 1. Analysis with cone beam computed tomography after remodelling of the buccal plate]. / Immediaat geplaatste fronttandimplantaten 1. Analyse met conebeamcomputertomografie naar remodellering van de buccale botlamel.

In the period 1 January 2008 to 1 January 2012, an implant was installed in 186 patients immediately after the removal of a maxillary incisor. Subsequent to the placement of the implant, the 2 mm gap between implant and buccal plate was filled with a bone substitute. In the case of 16 patients, in addition to a preoperative and immediately postoperative cone beam computer tomogram, a late-postoperative cone beam computer tomogram was also produced.Immediately post-operative, the buccal plate thickness increased by 1.5 mmfrom 0.9 mm to 2.4 mm. During the evaluation period of 1 to 4 years a reduction took place resulting in a final buccal plate thickness of 1.8 mm on average. Surprisingly, the buccal plate bone height increased by 1.6 mm, to an average of 1.2 mm above the implant shoulder. It was crucial in this case that the implant was placed in such a way that a gap of a minimum of 2.0 mm was created between the original buccal plate and the implant, and that this gap was filled with a bone substitute.

[Immediate front implant placements 2. Objective and subjective aesthetic treatment results]. / Immediaat geplaatste fronttandimplantaten 2. Objectief en subjectief esthetisch behandelresultaat.

In this study, the aesthetic outcome of treatment was analysed after immediate implant placement in 16 patients. During implant installation the gap between the implant and the buccal plate was filled with a bone substitute. Only single tooth replacements were included; the final crowns were placed 3-6 months after implant installation, all with individual manufactured abutments with an emerging profile and platform switching. Postoperative aesthetics were analysed based on clinical photographs and satisfactionquestionnaires. The objectively attained White Esthetic Score and Pink Esthetic Score with an average value of 8.4 and 11.8 respectively, scored high, as was also observed for patient's satisfaction on both treatment and outcome (an average of 8.7). It may be concluded that flapless immediate implant placement together with the application of a bone substitute into the buccal gap in combination with a final crown with emerging profile results in objective and subjective good aesthetics and high patient satisfaction.

Novel approach to quantify immobilized-enzyme distributions.

The quantitative intraparticle enzyme distribution of Assemblase, an industrially employed polydisperse immobilized penicillin-G acylase, was measured. Because of strong autofluorescence of the carrier, the generally applied technique of confocal scanning microscopy could not be used; light microscopy was our method of choice. To do so, Assemblase particles of various sizes were sectioned, labeled with antibodies specifically against the enzyme, and analyzed light microscopically. Image analysis software was developed and used to determine the intraparticle enzyme distribution, which was found to be heterogeneous, with most enzyme located in the outer regions of the particles. Larger particles showed steeper gradients than smaller ones. A mathematical representation of the intraparticle profiles, based on in-stationary enzyme diffusion into the particles, was validated successfully for a broad range of particle sizes using data for volume-averaged particle size and enzyme loading. The enzyme gradients determined in this work will be used as input for a physical model that quantitatively describes the complex behavior of Assemblase. Such a physical model will lead to identification of the current bottlenecks in Assemblase and can serve as a starting point for the design of improved biocatalysts that also may be based on intelligent use of enzyme gradients.

[Dental ingenuity 2. Implant treatment using transitional implants]. / Hoogtandjes 2. Implantologische behandeling met gebruik van transferimplantaten.

The applications in oral implantology are strongly increased due to the advance in the field of osseointegration and in material technology. As a result of this gained knowledge the area of indications increased in both edentulous and partially dentate patients. With the extension of the indications of dental implants there also is a growing patients' demand for direct replacement of lost tooth. Sometimes it is possible to fulfill the expressed wish of immediate loading. In case of poor bone quantity or quality this is impossible. Transitional implants supply the prosthodontist with an additional possibility to fulfill the need for uninterrupted healing as well as patients' demands for immediate functional and esthetic restorations.

[Two hospital staff with throat carriage of methicillin-resistant Staphylococcus aureus, which had to be treated with systemic antibiotics]. / Twee ziekenhuismedewerkers met keeldragerschap van meticillineresistente Staphylococcus aureus waarvoor systemische antibiotische behandeling noodzakelijk was.

Two hospital staff, women aged 20 and 22 years, were inadvertently found to be positive for methicillin-resistant Staphylococcus aureus (MRSA). Both had been in a hospital outside of the Netherlands, but due to the long period of time that had elapsed since then, they did not fall under the standard protocol for MRSA screening. After the usual wash procedure with chlorhexidine and mupirocin nasal ointment treatment, they remained positive for MRSA in the throat culture. Both patients still had their pharyngeal tonsils and were suffering from throat complaints. After systemic treatment with two antibiotics, they both became MRSA-free. Throat carriership of MRSA might be a reason why MRSA eradication fails in the case of apparently healthy healthcare workers. The addition of a throat culture to the screening of healthcare workers would therefore be useful.

Development of in vivo sponge cultures: particle feeding by the tropical sponge Pseudosuberites aff. andrewsi.

The rate of food particle uptake of the tropical sponge Pseudosuberites aff. andrewsi was studied in relation to particle concentrations and particle size. A range of different concentrations of either the marine microalga Dunaliella tertiolecta (approximately 5-8 microm) or the marine cyanobacterium Synechococcus sp. (approximately 1 microm) was supplied to the sponges. D. tertiolecta had a pronounced effect on the filtration activity of the sponges: at concentrations higher than approximately 4 x 10(5) cells/cm(3), the filtration rates dropped dramatically. Such a clear effect was not found for Synechococcus sp. The results further showed that the maximal amount of food (when expressed in organic carbon) that can be taken up per cubic centimeter of sponge volume per unit of time should in principle be sufficient to enable growth (irrespective of the food particle type). At the maximal food particle concentration that did not affect the filtration rates, the uptake of organic carbon is already highly in excess of the amount of organic carbon that the sponges need to cope with their respiratory demand. Based on these findings, a series of growth experiments was carried out in which the sponges were subjected to a constant concentration of different types of food particles (Synechococcus sp. and the microalgae Chlorella sorokiniana and Nannochloropsis sp). Although initial growth was sometimes observed, continuous growth at a constant rate could not be obtained. It is concluded that qualitative aspects of feeding rather than quantitative aspects are the key to successful in vivo sponge culture.

Improvement of the caries resistance of human dental roots by a two-step conversion of the root mineral into fluoridated hydroxylapatite.

Roots of extracted human molars were treated for both 10 and 30 min with a saturated solution of dicalcium phosphate dihydrate (DCPD) of pH 2.4 and subsequently with a 5.3 mmol.L-1 solution of sodium fluoride of pH 7.0. The objective of these combined treatments was to convert the highly-soluble root mineral into the less-soluble fluoridated hydroxylapatite, with DCPD as an intermediate, to improve caries resistance. The mineral content of the surface layer was not affected in a significant way. Roots treated in this way were subjected to 50 mmol.L-1 acetate buffer solutions of pH 5.5 and with pIOHA-values of 112, 116, and 122. The proportional reduction of the rate of demineralization (Vdem) of similarly treated roots subjected to buffer solutions of pIOHA 112 and 116 appeared to be equal initially. Since fluoridated hydroxylapatite is insoluble under these conditions, these findings are in agreement with expectations. The reduction of V dem amounted to about 45 and 70% for roots treated for 10 and 30 min, respectively. When roots were treated for 10 and 30 min and then exposed to buffer solutions with a pIOHA 122, reductions of V dem of about 30 and 55%, respectively, were found. Conversion of the root mineral into fluoridated hydroxylapatite can eliminate, in principle, the existing difference in caries susceptibility of the root and of the dental enamel.