22,103 research outputs found
Quantitative extraction of Meiofauna: A comparison of two methods
Two methods for the quantitative extraction of meiofauna from natural sandy sediments were investigated and compared: Cobb's decanting and sieving technique and the Oostenbrink elutriator. Both techniques were more efficient with pre-fixed samples than with fresh samples. The results indicated that elutriation is the more reliable method due to its low variability, 7,5% for nematodes and 8,4% for harpacticoids and mystacocarids compared to 11,2% and 29,0% respectively in the case of decantation. However, with samples containing 3 000 to 5 000 animals per 200 cc, decantation yielded 25% more animals than elutriation
Dynamic screening of a localized hole during photoemission from a metal cluster
Recent advances in attosecond spectroscopy techniques have fueled the
interest in the theoretical description of electronic processes taking place in
the subfemtosecond time scale. Here we study the coupled dynamic screening of a
localized hole and a photoelectron emitted from a metal cluster using a
semi-classical model. Electron density dynamics in the cluster is calculated
with Time-Dependent Density Functional Theory and the motion of the
photoemitted electron is described classically. We show that the dynamic
screening of the hole by the cluster electrons affects the motion of the
photoemitted electron. At the very beginning of its trajectory, the
photoemitted electron interacts with the cluster electrons that pile up to
screen the hole. Within our model, this gives rise to a significant reduction
of the energy lost by the photoelectron. Thus, this is a velocity dependent
effect that should be accounted for when calculating the average losses
suffered by photoemitted electrons in metals.Comment: 15 pages, 5 figure
Palliative Electrochemotherapy in Vulvar Carcinoma: Preliminary Results of the ELECHTRA (Electrochemotherapy Vulvar Cancer) Multicenter Study
Vulvar cancer (VC) is a rare disease of which recurrence poses management problems due to patients’ advanced age and comorbidities, and to the localization of the disease. Palliative treatments, allowing local disease control in patients previously treated with multimodal therapies or with comorbidities, are lacking. In this study we tested electrochemotherapy (ECT) on recurrent VC refractory to standard therapies to assess the tumor response and to define the selection criteria for patient’s candidate to ECT. This is a multicenter observational study carried out in five Italian centers. Data about patients and tumor characteristics, treatment, toxicity, and clinical response were recorded. In all procedures, intravenous bleomycin was administered according to European Standard Operative Procedure ECT (ESOPE) guidelines. Sixty-one patients, with a median age 79 years (range: 39–85) and mainly affected by squamous cellular carcinoma (91.8%), were treated with ECT. No serious adverse events were reported. Patients were discharged after three days (median, range: 0–8 days). Two months after ECT, the clinical response rate was 83.6% and was not related to age, body mass index, International Federation of Gynecology and Obstetrics (FIGO) stage, number of treated nodules, or previous treatments. ECT is a safe procedure with a favorable cost-effectiveness ratio and should be considered as a treatment option for local disease control in patients unsuitable for standard therapies
Recommended from our members
Laboratory and field evaluation of acetic acid-based lures for male Asian citrus psyllid, Diaphorina citri.
The Asian citrus psyllid (ACP) is a vector of a pathogen associated with greening and thus a major problem in citriculture worldwide. Lures are much needed for improving ACP trapping systems for monitoring populations and surveillance. Previously, we have identified acetic acid as a putative sex pheromone and measured formic acid- and propionic acid-elicited robust electroantennographic responses. We have now thoroughly examined in indoor behavioral assays (4-way olfactometer) and field tests the feasibility of these three semiochemicals as potential lures for trapping ACP. Formic acid, acetic acid, and propionic acid at appropriate doses are male-specific attractants and suitable lures for ACP traps, but they do not act synergistically. An acetic acid-based homemade lure, prepared by impregnating the attractant in a polymer, was active for a day. A newly developed slow-release formulation had equal performance but lasted longer, thus leading to an important improvement in ACP trap capture at low population densities
Epileptic Spasms in Congenital Disorders of Glycosylation
Congenital disorders of glycosylation (CDG) are a group of rare metabolic diseases, characterized by impaired glycosylation. Multisystemic involvement is common and neurological impairment is notably severe and disabling, concerning the central and peripheral nervous system. Epilepsy is frequent, but detailed electroclinical description is rare. We describe, retrospectively, the electroclinical features in five children with CDG and epileptic spasms. Epileptic spasms were observed in patients with ALG1-, ALG6, ALG11-CDG and CDG-Ix, and occurred at an early age, before 6 months in all cases, except one who had spasms that started at 18 months. In this patient, spasms had an unusual aspect; they did not occur in clusters and were immediately preceded by a myoclonus. All but one child also presented rare myoclonias. On EEG, background activity was poorly organized with abundant posterior spike and fast rhythm activity, but without hypsarrhythmia. At the last evaluation (age range: 6-12 years), two patients still presented epileptic spasms and subcortical myoclonias, one showed rare generalized tonic-clonic seizures, and two were seizure-free. CDG disorders can be associated with epileptic spasms showing particular features, such as absence of hypsarrhythmia, posterior EEG anomalies, and an unusual combination of epileptic spasms with myoclonus. These features, associated with pre-existing developmental delay and subcortical myoclonias, may shift toward CDG screening. [Published with video sequence and supplemental EEG plates on www.epilepticdisorders.com].info:eu-repo/semantics/publishedVersio
Young children's cognitive achievement: home learning environment, language and ethnic background
For decades, research has shown differences in cognitive assessment scores between White and minority ethnic group(s) learners as well as differences across different minority ethnic groups. More recent data have indicated that the home learning environment and languages spoken can impact cognitive assessment and other corollary outcomes. This study uses the Millennium Cohort Study to jointly assess how minority ethnic group, home learning environment and home languages predict child cognitive assessment scores. Regression analyses were conducted using two assessment measures. The following is hypothesised: (1) cognitive achievement scores vary by minority ethnic group, (2) more home learning environment in early childhood leads to higher cognitive development scores and (3) English only in the home yields the highest cognitive scores while no English in the home yields the lowest. Findings reveal that there are differences in cognitive scores along ethnic group categories although there are also some unexpected findings. Home learning environment does not play as large a role as was predicted in raising the assessment scores overall for learners while speaking English in the home does, irrespective of ethnic background
Ultrahard carbon film from epitaxial two-layer graphene
Atomically thin graphene exhibits fascinating mechanical properties, although
its hardness and transverse stiffness are inferior to those of diamond. To
date, there hasn't been any practical demonstration of the transformation of
multi-layer graphene into diamond-like ultra-hard structures. Here we show that
at room temperature and after nano-indentation, two-layer graphene on SiC(0001)
exhibits a transverse stiffness and hardness comparable to diamond, resisting
to perforation with a diamond indenter, and showing a reversible drop in
electrical conductivity upon indentation. Density functional theory
calculations suggest that upon compression, the two-layer graphene film
transforms into a diamond-like film, producing both elastic deformations and
sp2-to-sp3 chemical changes. Experiments and calculations show that this
reversible phase change is not observed for a single buffer layer on SiC or
graphene films thicker than 3 to 5 layers. Indeed, calculations show that
whereas in two-layer graphene layer-stacking configuration controls the
conformation of the diamond-like film, in a multilayer film it hinders the
phase transformation.Comment: Published online on Nature Nanotechnology on December 18, 201
Recommended from our members
The blocks of the partition algebra in positive characteristic
In this paper we describe the blocks of the partition algebra over a field of positive characteristic
- …