Selecting features for BCI control based on a covert spatial attention paradigm

Covert attention to spatial locations in the visual field is a relatively new control signal for brain–computer interfaces. Previous EEG research has shown that trials can be classified by thresholding based on left and right hemisphere alpha power in covert spatial attention paradigms. We reexamine the covert attention paradigm based on MEG measurements for fifteen subjects. It is shown that classification performance can be improved by applying sparse logistic regression in order to select a subset of the sensors specific to each subject as the basis for classification. Furthermore, insight is gained into how classification performance changes as a function of the length of the attention period and as a function of the number of trials. Classification performance steadily increases as the length of the attention period over which is averaged is increased, although this does not necessarily translate into higher bit rates. Good classification performance using early components of the attention period may be related to evoked response. With regard to the number of used trials, classification performance became maximal after 150 samples had been obtained, requiring a training time of approximately eleven minutes under the current experimental paradigm.     

Epidemiologic and Genomic Analysis of SARS-CoV-2 Delta Variant Superspreading Event in Nightclub,the Netherlands,June 2021

We report a severe acute respiratory syndrome coronavirus 2 superspreading event in the Netherlands after distancing rules were lifted in nightclubs, despite requiring a negative test or vaccination. This occurrence illustrates the potential for rapid dissemination of variants in largely unvaccinated populations under such conditions. We detected subsequent community transmission of this strain.     

Experiences with High Doses of Furosemide in Renal Disease and Resistant Edematous States

Six cases of edema, three due to the nephrotic syndrome, one to congestive heart failure and two to chronic renal failure, are reported in which furosemide was administered in oral doses higher than those usually prescribed (up to 720 mg. a day), in order to obtain a satisfactory diuresis. In one case of severe prerenal failure secondary to cardiogenic shock and in one case of acute tubular necrosis secondary to hypotension at the time of operation, intravenous doses up to 990 and 1400 mg. per day respectively were able to reverse the oliguria. In eight additional patients who were on chronic hemodialysis, furosemide was administered to the amount of 1000 mg. per day orally in divided doses for two weeks, and produced a moderate diuretic response.

The use of high doses of furosemide in edema and renal failure resistant to the usual therapeutic measures appears to be safe and effective.

     

Rapid radiosynthesis of [11C] and [14C]azelaic,suberic, and sebacic acids for in vivo mechanistic studies of systemic acquired resistance in plants

A recent report that the aliphatic dicarboxylic acid, azelaic acid (1,9‐nonanedioic acid) but not related acids, suberic acid (1,8‐octanedioic acid) or sebacic (1,10‐decanedioic acid) acid induces systemic acquired resistance to invading pathogens in plants stimulated the development of a rapid method for labeling these dicarboxylic acids with ¹¹C and ¹⁴C for in vivo mechanistic studies in whole plants. ¹¹C‐labeling was performed by reaction of ammonium [¹¹C]cyanide with the corresponding bromonitrile precursor followed by hydrolysis with aqueous sodium hydroxide solution. Total synthesis time was 60 min. Median decay‐corrected radiochemical yield for [¹¹C]azelaic acid was 40% relative to trapped [¹¹C]cyanide, and specific activity was 15 GBq/µmol. Yields for [¹¹C]suberic and sebacic acids were similar. The ¹⁴C‐labeled version of azelaic acid was prepared from potassium [¹⁴C]cyanide in 45% overall radiochemical yield. Radiolabeling procedures were verified using ¹³C‐labeling coupled with ¹³C‐NMR and liquid chromatography–mass spectrometry analysis. The ¹¹C and ¹⁴C‐labeled azelaic acid and related dicarboxylic acids are expected to be of value in understanding the mode‐of‐action, transport, and fate of this putative signaling molecule in plants. Copyright © 2011 John Wiley & Sons, Ltd.     

Donor interleukin-4 promoter gene polymorphism influences allograft rejection after heart transplantation.

BACKGROUND: The cytokine interleukin-4 (IL-4) is secreted mainly by activated T lymphocytes and characterizes the T-helper 2 (Th2) sub-type. In transplantation Th2 cells are believed to induce graft tolerance. Previous studies revealed that patients with a relatively high frequency of IL-4 producing helper T lymphocytes (HTL) before heart transplantation (HTX) had no or less rejection episodes compared with patients with a low frequency of IL-4 producing HTL. Three single nucleotide polymorphisms (SNPs) have been identified in the promoter region of the IL-4 gene, which influence promoter strength. We investigated whether there was a correlation between SNP genotypes in the IL-4 promoter and heart failure, and rejection after HTX. METHODS: Seventy HTX patients, 61 donors, and 36 controls were genotyped for the 3 SNPs by sequencing. RESULTS: Of the SNPs at -285 and -81, only the C and A alleles, respectively, were found in this study. Both alleles were found for the -590 SNP. No relation between patient genotype of the SNP at -590 and heart failure and rejection was found. However, incidence of rejection was significantly lower in patients that received a donor heart with the T-positive genotype compared with patients that received a heart from a T-negative donor. Patients who had the T-negative genotype and received a heart from a T-positive donor, suffered significantly less from rejection than T-negative patients that received a T-negative donor heart. This was not significant in the T-positive patient group. CONCLUSIONS: This indicates that IL-4 production within the donor heart and by cells from the donor is important for reducing incidence of episodes of rejection.     

In vitro and in vivo tissue repair with laser-activated chitosan adhesive

BACKGROUND AND OBJECTIVES: Sutures are currently the gold standard for wound closure but they are still unable to seal tissue and may induce scarring or inflammation. Biocompatible glues, based on polysaccharides such as chitosan, are a possible alternative to conventional wound closure. In this study, the adhesion of laser-activated chitosan films is investigated in vitro and in vivo. In particular we examine the effect of varying the laser power, as well as adding a natural cross-linker (genipin) to the adhesive composition. STUDY DESIGN/MATERIALS AND METHODS: Flexible and insoluble strips of chitosan films (surface area approximately 34 mm(2), thickness approximately 20 microm) were bonded to sheep intestine using several laser powers (0, 80, 120, and 160 mW) at 808-nm wavelength. The strength of repaired tissue was tested by a calibrated tensiometer to select the best power. A natural cross-linker (genipin) was also added to the film and the tissue repair strength compared with the strength of plain films. The adhesive was also bonded in vivo to the sciatic nerve of rats and the thermal damage induced by the laser assessed 4 days post-operatively. RESULTS: Chitosan adhesives successfully repaired intestine tissue, attaining a maximum repair strength of 14.7+/-4.3 kPa (n = 30) at the laser power of 120 mW. The chitosan-genipin films achieved lower repair strength (9.1+/-2.9 kPa). The laser caused partial demyelination of axons at the site of operation, but the myelinated axons retained a normal morphology proximally and distally. CONCLUSIONS: The chitosan adhesive effectively bonded to tissue causing only localized thermal damage in vivo, when the appropriate laser parameters were selected.