Fully decentralized robust backstepping voltage control of photovoltaic systems for DC islanded microgrids based on disturbance observer method

In this paper, a new backstepping-based nonlinear technique for control of photovoltaic systems in DC islanded microgrids (MGs) is proposed. In contrast to most existing droop/non-droop control strategies that require an exact model of the system including line impedances, loads, other distributed generation units (DGUs) parameters, and even the MG configuration, the proposed method is taking dynamics and uncertainties into account using a designed disturbance observer. Moreover, the proposed method rapidly reaches the reference values and exhibits a more accurate robust performance using local quantities measurement, irrespective of parametric uncertainties, unmodeled dynamics, unknown loads, disturbances, and the number/structure of DGs within the MG. Finally, a low-voltage DC MG is built where the robust performance of the proposed method for different operating conditions including load variation, tracking capability, nonlinear loads, and plug-play of DGs is verified.

Patient-centredness in acute stroke care - a qualitative study from the perspectives of patients, relatives and staff

BACKGROUND AND PURPOSE

Although patient-centredness is considered a key component of high-quality neurological care, it is unclear to what extent it can or should be implemented during the acute phase. Using acute stroke as an example, the aim was to identify critical junctures for patient-centredness along the acute care pathway from the perspectives of patients, relatives and staff.

METHODS

A qualitative multi-method study was conducted including 27 non-participant observations and 37 semi-structured interviews with patients, relatives and staff. Junctures were defined as critical when mentioned (as problematic) in two or three information sources (i.e. observations, staff interviews, or patient and relative interviews), as potentially critical when mentioned in one, and as uncritical when not mentioned.

RESULTS

Post-procedure communication after thrombectomy, patients' stay at the stroke unit and decision-making around transfer, discharge and rehabilitation were identified as critical junctures for patient-centredness. Arrival at the emergency department and the (thrombectomy) treatment itself were identified as uncritical junctures, whilst history-taking and treatment preparation, the treatment decision and patients' stay at the intensive care unit were identified as potentially critical junctures.

CONCLUSIONS

In acute stroke care, patients, relatives and staff prioritize fast over patient-centred decision-making in the most time-critical phases, especially before and during treatment. This is reversed after the procedure, when difficulties arise implementing a patient-centred approach in clinical practice. To improve patient-centredness where it is most needed, clear guidelines and accessible resources are recommended. Future research should investigate whether insights from acute phases of stroke care are applicable to other neurological conditions as well.

Coenzyme Q10 improves the survival and reduces inflammatory markers in septic patients

OBJECTIVE

This study aimed to evaluate the effect of Coenzyme Q10 (CoQ10) administration to patients in the early phase of sepsis to determine its effect on the markers of inflammation and the clinical outcomes of septic patients.

BACKGROUND

Previous studies showed that CoQ10 levels were decreased in septic patients and worsening of mitochondrial dysfunction was observed.

METHODS

In this randomized controlled trial septic patients (n=40) received 100 mg CoQ10 twice a day for seven days added to standard treatment of sepsis. As a primary endpoint levels of Interleukin 6 (IL-6), Tumor Necrosis Factor-α (TNF-α), Glutathione peroxidase and malondialdehyde (MDA) were assessed at baseline, third and 7th day after the intervention. Secondary endpoints included assessment of clinical scores and     in-hospital mortality.

RESULTS

There was no difference in baseline inflammatory and oxidative injury markers between the groups. TNF-α and MDA levels decreased significantly in the CoQ10 group on the 7th day of the study (P:0.003 for both). There was a significant difference in the in-hospital mortality in the CoQ10 group compared to the control group (P:0.01).

CONCLUSION

These findings suggest that CoQ10 has a positive effect on clinical parameters as well as mitochondrial dysfunction when administered in the early phase of sepsis (Tab. 2, Fig. 1, Ref. 38).

Validation of mean upper cervical cord area (MUCCA) measurement techniques in multiple sclerosis (MS): High reproducibility and robustness to lesions, but large software and scanner effects

Introduction

Atrophy of the spinal cord is known to occur in multiple sclerosis (MS). The mean upper cervical cord area (MUCCA) can be used to measure this atrophy. Currently, several (semi-)automated methods for MUCCA measurement exist, but validation in clinical magnetic resonance (MR) images is lacking.

Methods

Five methods to measure MUCCA (SCT-PropSeg, SCT-DeepSeg, NeuroQLab, Xinapse JIM and ITK-SNAP) were investigated in a predefined upper cervical cord region. First, within-scanner reproducibility and between-scanner robustness were assessed using intra-class correlation coefficient (ICC) and Dice's similarity index (SI) in scan-rescan 3DT1-weighted images (brain, including cervical spine using a head coil) performed on three 3 T MR machines (GE MR750, Philips Ingenuity, Toshiba Vantage Titan) in 21 subjects with MS and 6 healthy controls (dataset A). Second, sensitivity of MUCCA measurement to lesions in the upper cervical cord was assessed with cervical 3D T1-weighted images (3 T GE HDxT using a head-neck-spine coil) in 7 subjects with MS without and 14 subjects with MS with cervical lesions (dataset B), using ICC and SI with manual reference segmentations.

Results

In dataset A, MUCCA differed between MR machines (p < 0.001) and methods (p < 0.001) used, but not between scan sessions. With respect to MUCCA values, Xinapse JIM showed the highest within-scanner reproducibility (ICC absolute agreement = 0.995) while Xinapse JIM and SCT-PropSeg showed the highest between-scanner robustness (ICC consistency = 0.981 and 0.976, respectively). Reproducibility of segmentations between scan sessions was highest in Xinapse JIM and SCT-PropSeg segmentations (median SI ≥ 0.921), with a significant main effect of method (p < 0.001), but not of MR machine or subject group. In dataset B, SI with manual outlines did not differ between patients with or without cervical lesions for any of the segmentation methods (p > 0.176). However, there was an effect of method for both volumetric and voxel wise agreement of the segmentations (both p < 0.001). Highest volumetric and voxel wise agreement was obtained with Xinapse JIM (ICC absolute agreement = 0.940 and median SI = 0.962).

Conclusion

Although MUCCA is highly reproducible within a scanner for each individual measurement method, MUCCA differs between scanners and between methods. Cervical cord lesions do not affect MUCCA measurement performance.

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Mean upper cervical cord area (MUCCA) was obtained with five different methods.

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MUCCA was determined in a unique scan-rescan multi-vendor MR study.

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Reproducibility: MUCCA did not differ between scan-rescan images for any method.

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Robustness: MUCCA differed between methods and between scanners.

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Performance of MUCCA methods was not affected by the presence of lesions.

Reproducibility of Deep Gray Matter Atrophy Rate Measurement in a Large Multicenter Dataset

BACKGROUND AND PURPOSE

Precise in vivo measurement of deep GM volume change is a highly demanded prerequisite for an adequate evaluation of disease progression and new treatments. However, quantitative data on the reproducibility of deep GM structure volumetry are not yet available. In this paper we aim to investigate this reproducibility using a large multicenter dataset.

MATERIALS AND METHODS

We have assessed the reproducibility of 2 automated segmentation software packages (FreeSurfer and the FMRIB Integrated Registration and Segmentation Tool) by quantifying the volume changes of deep GM structures by using back-to-back MR imaging scans from the Alzheimer Disease Neuroimaging Initiative's multicenter dataset. Five hundred sixty-two subjects with scans at baseline and 1 year were included. Reproducibility was investigated in the bilateral caudate nucleus, putamen, amygdala, globus pallidus, and thalamus by carrying out descriptives as well as multilevel and variance component analysis.

RESULTS

Median absolute back-to-back differences varied between GM structures, ranging from 59.6-156.4 μL for volume change, and 1.26%-8.63% for percentage volume change. FreeSurfer had a better performance for the outcome of longitudinal volume change for the bilateral amygdala, putamen, left caudate nucleus (P < .005), and right thalamus (P < .001). For longitudinal percentage volume change, Freesurfer performed better for the left amygdala, bilateral caudate nucleus, and left putamen (P < .001). Smaller limits of agreement were found for FreeSurfer for both outcomes for all GM structures except the globus pallidus. Our results showed that back-to-back differences in 1-year percentage volume change were approximately 1.5-3.5 times larger than the mean measured 1-year volume change of those structures.

CONCLUSIONS

Longitudinal deep GM atrophy measures should be interpreted with caution. Furthermore, deep GM atrophy measurement techniques require substantially improved reproducibility, specifically when aiming for personalized medicine.

Hybrid segmentation of fluorescent Leschmania-infected images using a watersched and combined region merging based method

Automatic parasite segmentation in fluorescent images is of high importance as it serves as an easier and faster tool for detecting and counting parasites in each focus. In this paper we present a hybrid segmentation for the Promastigote form of Leishmania parasites in Indirect Immunofluorescence (IIF) images, combining edge and region-based techniques through the morphological algorithm of watershed. The proposed approach deals first with a pre-processing step to correct illumination non-uniformities in the fluorescence Leishmania-infected images before performing the initial segmentation by means of the watershed algorithm. A merging step using joint region homogeneity and edge integrity criteria is then applied to improve the segmentation results. Segmentation tests of 1438 parasites from 40 collected IIF images illustrate the efficiency of our approach.

Comparison of two DNA extraction protocols from leave samples of Cotinus coggygria, Citrus sinensis and Genus juglans

High quality DNA is essential for molecular research. Secondary metabolites can affect the quantity and quality DNA. In current research two DNA isolation methods including CTAB and Delaporta (protocols 1 &amp; 2 respectively) were applied in three leave samples from Cotinus coggygria, Citrus sinensis and Genus juglans that their leaves are rich of secondary metabolites. We successfully isolated DNA from C. coggygria, C. sinensis and Genus Juglans using the two protocols described above. Good quality DNA was isolated from C. coggygria, C. sinensis and Genus Juglans using protocol 1, while protocol 2 failed to produce usable DNA from these sources. The highest amount of DNA (1.3-1.6) was obtained from them using protocol 1. As we discovered, procedure 1 may work better for plants with secondary metabolites.

Adaptive automatic segmentation of Leishmaniasis parasite in Indirect Immunofluorescence images

This paper describes the first steps for the automation of the serum titration process. In fact, this process requires an Indirect Immunofluorescence (IIF) diagnosis automation. We deal with the initial phase that represents the fluorescence images segmentation. Our approach consists of three principle stages: (1) a color based segmentation which aims at extracting the fluorescent foreground based on k-means clustering, (2) the segmentation of the fluorescent clustered image, and (3) a region-based feature segmentation, intended to remove the fluorescent noisy regions and to locate fluorescent parasites. We evaluated the proposed method on 40 IIF images. Experimental results show that such a method provides reliable and robust automatic segmentation of fluorescent Promastigote parasite.

[Treatment of asymptomatic carotid artery stenosis: improvement of evidence with new SPACE-2 design necessary]

Asymptomatic carotid artery stenosis may be treated with carotid endarterectomy (CEA), carotid artery stenting (CAS) or with best medical treatment (BMT) only. Definitive and evidence-based treatment recommendations for one of these options are currently not possible. Studies showing an advantage of CEA over BMT alone do not meet current standards from a pharmacological point of view. On the other hand, more recent data point to a further stroke risk reduction using BMT according to current standards. Studies on carotid artery stenting as a third alternative treatment are partially insufficient, especially when comparing CAS with BMT. Initiated in 2009, the randomized, controlled, multicenter SPACE-2 trial is intended to answer the question about the best treatment option of asymptomatic carotid artery stenosis; however, to increase recruitment rates as a condition for the successful completion of this important study, the trial design had to be modified.

Chemical composition, antibacterial activity and cytotoxicity of essential oils of Tanacetum parthenium in different developmental stages

CONTEXT

Tanacetum parthenium Schultz Bip. (Asteraceae) is an aromatic perennial plant, widely distributed in the northern hemisphere. This species traditionally has been used in insecticides, cosmetics, balsams, dyes, medicines and preservatives.

MATERIAL AND METHODS

The essential oil of T. parthenium was obtained by hydrodistillation in three developmental stages and analyzed by gas chromatography-mass spectrometry. The antibacterial activity of the oils was investigated against four Gram-positive and four Gram-negative bacteria. The oil was tested for cytotoxicity against THP-1 cells using the Trypan blue assay.

RESULTS

Twenty-nine components were identified in the essential oil; the highest amount was extracted at the flowering stage. The main component, in the flowering stage, was camphor (18.94%) and other major components were bornyl acetate (18.35%), camphene (13.74%), bornyl isovalerate (3.15%), borneol (10.93%), juniper camphor (6.23%) and β-eudesmol (2.65%). Minimum inhibitory concentration of essential oil was evaluated from 4 µL mL(-1) against Staphylococcus subtilis to 38 µL mL(-1) against Entrobacter aerogenes. Toxicity assay showed that the oil has no significant toxicity at 5-15% v/v concentrations on THP-1 cells.

DISCUSSION AND CONCLUSION

This study demonstrates the occurrence of camphor/bornyl acetate chemotype of T. parthenium in western regions of Iran. The finding showed also the studied oils have relatively good antibacterial activity without significant toxicity, thus have great potentiality to be used as natural health product.

Intravenous dexamethasone versus morphine in relieving of acute migraine headache

Inflammation is thought to play a significant role in the underlying pathophysiology of migraine headaches which could be controlled by corticosteroids. The present study was conducted to determine and compare the pain relieving effect of dexamethasone versus morphine on patients with acute migraine headache. During this double blinded clinical trial study, 190 patients who met the International Headache Society definition of acute migraine headache were evaluated at emergency department of Tabriz Imam Reza Hospital. After giving informed consent, patients were randomly enrolled into two groups: Receiving either 8 mg dexamethasone (group A) or 0.1 mg kg(-1) morphine (group B) intravenously. Severity of the headache was determined using Visual Analog Scale (VAS) scoring method at baseline (VAS-A), 10 min (VAS-B), 60 min (VAS-C) and 24 h (VAS-D) after intervention. The mean age of patients was 44.17 +/- 16.20 years, 61.57% male and 38.43% female. The mean of VAS-A and VAS-B scores was not statistically different between two groups (p = 0.236 and p = 0.481), but the mean of VAS-C and VAS-D scores in the group A were significantly lower than the group B (p = 0.017, p = 0.010). In long-term (1 h and 24 h after administration), dexamethasone reduces the severity of acute migrant headache more than morphine.

A chimeric disposition of the elongation factor genes in Rickettsia prowazekii

An exceptional disposition of the elongation factor genes is observed in Rickettsia prowazekii, in which there is only one tuf gene, which is distant from the lone fus gene. In contrast, the closely related bacterium Agrobacterium tumefaciens has the normal bacterial arrangement of two tuf genes, of which one is tightly linked to the fus gene. Analysis of the flanking sequences of the single tuf gene in R. prowazekii shows that it is preceded by two of the four tRNA genes located in the 5' region of the Escherichia coli tufB gene and that it is followed by rpsJ as well as associated ribosomal protein genes, which in E. coli are located downstream of the tufA gene. The fus gene is located within the str operon and is followed by one tRNA gene as well as by the genes secE and nusG, which are located in the 3' region of tufB in E. coli. This atypical disposition of genes suggests that intrachromosomal recombination between duplicated tuf genes has contributed to the evolution of the unique genomic architecture of R. prowazekii.

Colonic malakoplakia in a child: report of a case and review of literature

The fifth case of colonic malakoplakia involving children under the age of 13 years is reported. Rectoscopic findings were strongly suggestive of a colonic carcinoma. A detailed review of literature on malakoplakia is also made.