Information about the relative importance of competitive or facilitative pollinator‐mediated interactions in a multi‐species context is limited. We studied interspecific pollen transfer (IPT) ...networks to evaluate quantity and quality effects of pollinator sharing among plant species on three high‐Andean communities at 1600, 1800 and 2000 m a.s.l. To estimate the sign of the effects (positive, neutral or negative), the relation between conspecific and heterospecific pollen deposited on stigmas was analysed with GLMMs. Network analyses showed that communities were characterised by the presence of pollen hub‐donors and receptors. We inferred that facilitative and neutral pollinator‐mediated interactions among plants prevailed over competition. Thus, the benefits from pollinator sharing seem to outweigh the costs (i.e. heterospecific deposition and conspecific pollen loss). The largest proportion of facilitated species was found at the highest elevation community, suggesting that under unfavourable conditions for the pollination service and at lower plant densities facilitation can be more common.
Objectives
To investigate if quantitative apparent diffusion coefficient (ADC) measurements can predict genetic subtypes of non-gadolinium-enhancing gliomas, comparing whole tumour against single ...slice analysis.
Methods
Volumetric T2-derived masks of 44 gliomas were co-registered to ADC maps with ADC mean (ADC
mean
) calculated. For the slice analysis, two observers placed regions of interest in the largest tumour cross-section. The ratio (ADC
ratio
) between ADC
mean
in the tumour and normal appearing white matter was calculated for both methods.
Results
Isocitrate dehydrogenase (IDH) wild-type gliomas showed the lowest ADC values throughout (
p
< 0.001). ADC
mean
in the IDH-mutant 1p19q intact group was significantly higher than in the IDH-mutant 1p19q co-deleted group (
p
< 0.01). A volumetric ADC
mean
threshold of 1201 × 10
−6
mm
2
/s identified IDH wild-type with a sensitivity of 83% and a specificity of 86%; a volumetric ADC
ratio
cut-off value of 1.65 provided a sensitivity of 80% and a specificity of 92% (area under the curve (AUC) 0.9–0.94). A slice ADC
ratio
threshold for observer 1 (observer 2) of 1.76 (1.83) provided a sensitivity of 80% (86%), specificity of 91% (100%) and AUC of 0.95 (0.96). The intraclass correlation coefficient was excellent (0.98).
Conclusions
ADC measurements can support the distinction of glioma subtypes. Volumetric and two-dimensional measurements yielded similar results in this study.
Key Points
• Diffusion-weighted MRI aids the identification of non-gadolinium-enhancing malignant gliomas
• ADC measurements may permit non-gadolinium-enhancing glioma molecular subtyping
• IDH wild-type gliomas have lower ADC values than IDH-mutant tumours
• Single cross-section and volumetric ADC measurements yielded comparable results in this study
To evaluate whether oligoclonal bands (OB) add information to MRI in predicting both a second attack and development of disability in patients with clinically isolated syndromes (CIS).
From 1995 to ...2006, 572 patients with CIS were included in a prospective study. Patients underwent brain MRI and determination of OB within 3 months of first attack. The number and location of lesions and presence of OB were studied. We analyzed time to second attack and to Expanded Disability Status Scale 3.0 according to number of Barkhof criteria (BC) and the presence or absence of OB.
We studied 415 (73%) patients with CIS with both baseline MRI and determination of OB. Patients were followed for a mean of 50 months (SD 31). Compared to the reference group with 0 BC at baseline MRI, patients with one to two BC showed a hazard ratio (HR) for conversion to CDMS of 3.8 (2.0 to 7.2) and patients with three to four BC of 8.9 (4.8 to 16.4). Of the total cohort, OB were positive in 61% of the patients. However, broken down by MRI group, OB were positive in 31% of those with no BC; 69% of those with one to two BC; and 85% of those with three or four BC. The presence of OB increased the risk of a second relapse (HR 1.7; 1.1 to -2.7) independently of baseline MRI but did not modify the development of disability.
Presence of oligoclonal bands doubles the risk for having a second attack, independently of MRI, but does not seem to influence the development of disability.
Many vertebrate species act as both plant pollinators and seed-dispersers, thus interconnecting these processes, particularly on islands. Ecological multilayer networks are a powerful tool to explore ...interdependencies between processes; however, quantifying the links between species engaging in different types of interactions (i.e. inter-layer edges) remains a great challenge. Here, we empirically measured inter-layer edge weights by quantifying the role of individually marked birds as both pollinators and seed-dispersers of Galápagos plant species over an entire year. Although most species (80%) engaged in both functions, we show that only a small proportion of individuals actually linked the two processes, highlighting the need to further consider intra-specific variability in individuals' functional roles. Furthermore, we found a high variation among species in linking both processes, i.e. some species contribute more than others to the modular organization of the multilayer network. Small and abundant species are particularly important for the cohesion of pollinator seed-dispersal networks, demonstrating the interplay between species traits and neutral processes structuring natural communities.
We present new microTEGs based on doped Bi2Te3 thin films deposited on polyimide membrane able to operate under a temperature difference as high as 280 K. We developed two microTEGs with different ...designs to obtain the lowest internal resistance possible. The thermoelectrical properties coupled to the low contact resistance lead to an open circuit voltage of 64 mV and a maximum output power of 36 µW under a temperature difference of 206 K. Such high temperature difference cannot be obtain in bulk commercial TEG systems; it is maintained without heat sink but only using a copper ring supporting a thin polyimide membrane. These thermoelectric devices deposited on suspended polyimide membranes open new ways for waste heat applications, in particular by direct mechanical and thermal contact with hot sources.
Display omitted
•We present new microTEGs based on doped Bi2Te3 thin films deposited on polyimide membrane.•An open circuit voltage of 64 mV and a maximum output power of 36 µW under a temperature difference of 206 K is obtained.•The temperature difference up to 206 K is obtained without heat sink but only using a copper ring.
Background: Therapy for multiple sclerosis (MS) has a partial efficacy, and a significant proportion of treated patients will develop a suboptimal response with first‐line disease‐modifying drugs ...(DMD). Therapy switch in patients with MS can be a strategy after a treatment failure. We studied the change in clinical activity after switching of first‐line DMD because of a treatment failure.
Methods: Relapsing‐remitting multiple sclerosis (RRMS) patients treated with interferon‐beta (IFNB) or glatiramer acetate (GA) were divided into (i) patients without change in DMD, (ii) patients with a change in DMD because of a poor response, and (iii) those with a change in DMD without relation with response. Annualized relapse rate (ARR) and relapse‐free proportions were analyzed.
Results: We identified 923 patients with RRMS. Of the 180 who experienced a change because of suboptimal response, 90 switched to another first‐line DMT, 38 to mitoxantrone, and 52 to natalizumab. Median ARR in the pre‐DMD period on first DMD and second DMD was the following: 1, 1, and 0 for switchers from IFNB to another IFNB (P = 0.0001); 0.67, 1, and 0 for switchers from GA to IFNB (P = 0.01); 1, 1, and 0 for switchers from an IFNB to GA (P = 0.02); 1.1, 1.5, 0.2 for switchers from IFNB or GA to mitoxantrone (P = 0.0001); 0.9, 1, 0 for switchers from IFNB or GA to natalizumab (P = 0.0001).
Conclusions: In patients with RRMS who have a poor response, switch to another DMD may reduce the clinical activity of the disease.
Brain structural covariance networks (SCNs) based on pairwise statistical associations of cortical thickness data across brain areas reflect underlying physical and functional connections between ...them. SCNs capture the complexity of human brain cortex structure and are disrupted in neurodegenerative conditions. However, the longitudinal assessment of SCN dynamics has not yet been explored, despite its potential to unveil mechanisms underlying neurodegeneration. Here, we evaluated the changes of SCNs over 12 months in patients with a first inflammatory-demyelinating attack of the Central Nervous System and assessed their clinical relevance by comparing SCN dynamics of patients with and without conversion to multiple sclerosis (MS) over one year. All subjects underwent clinical and brain MRI assessments over one year. Brain cortical thicknesses for each subject and time point were used to obtain group-level between-area correlation matrices from which nodal connectivity metrics were obtained. Robust bootstrap-based statistical approaches (allowing sampling with replacement) assessed the significance of longitudinal changes. Patients who converted to MS exhibited significantly greater network connectivity at baseline than non-converters (p = 0.02) and a subsequent connectivity loss over time (p = 0.001-0.02), not observed in non-converters' network. These findings suggest SCN analysis is sensitive to brain tissue changes in early MS, reflecting clinically relevant aspects of the condition. However, this is preliminary work, indicated by the low sample sizes, and its results and conclusions should be treated with caution and confirmed with larger cohorts.
Background:
A pseudoatrophy effect has been held responsible for the lack of net impact of natalizumab on brain volume outcomes in 2-year trials, but no data are available beyond 24 months.
...Objective:
We aimed to investigate brain volume dynamics in natalizumab-treated patients in up to 3 years after therapy initiation with clinical correlations.
Methods:
Patients on natalizumab for at least 3 years were clinically assessed 3-monthly. Magnetic resonance imaging scans were performed at baseline and yearly. Brain volume changes were obtained with SIENA. Multivariate models were used to investigate the association between baseline inflammation and changes in brain volume and disability.
Results:
Sixty-two patients with multiple sclerosis were analysed. Mean age and disease duration were 34.7 (SD: 8.3) and 10.4 (SD: 6.6) years. Presence of gadolinium enhancement at baseline was not associated with Expanded Disability Status Scale changes (p=0.468), but was associated with larger brain volume decreases (p=0.005) in the first (p=0.024) and second year (p=0.019) but not in the third year (p=0.863). Brain volume changes at 12 and 36 months were marginally associated with disability status at month 12 (p=0.094) and 36 (p=0.084), respectively.
Conclusions:
Baseline inflammation affects brain volume measures up to 24 months after natalizumab initiation. A marginal association of brain volume changes with disability is present.
The ratios of inclusive electron scattering cross sections of 4He, 12C, and 56Fe to 3He have been measured at 1 < xB <. At Q2 > 1.4 GeV2, the ratios exhibit two separate plateaus, at 1.5 < xB < 2 and ...at xB > 2.25. This pattern is predicted by models that include 2- and 3-nucleon short-range correlations (SRC). Relative to A = 3, the per-nucleon probabilities of 3-nucleon SRC are 2.3, 3.1, and 4.4 times larger for A = 4, 12, and 56. This is the first measurement of 3-nucleon SRC probabilities in nuclei.
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