1,164 research outputs found
Enhancement of charged macromolecule capture by nanopores in a salt gradient
Nanopores spanning synthetic membranes have been used as key components in
proof-of-principle nanofluidic applications, particularly those involving
manipulation of biomolecules or sequencing of DNA. The only practical way of
manipulating charged macromolecules near nanopores is through a voltage
difference applied across the nanopore-spanning membrane. However, recent
experiments have shown that salt concentration gradients applied across
nanopores can also dramatically enhance charged particle capture from a low
concentration reservoir of charged molecules at one end of the nanopore. This
puzzling effect has hitherto eluded a physically consistent theoretical
explanation. Here, we propose an electrokinetic mechanism of this enhanced
capture that relies on the electrostatic potential near the pore mouth. For
long pores with diameter much greater than the local screening length, we
obtain accurate analytic expressions showing how salt gradients control the
local conductivity which can lead to increased local electrostatic potentials
and charged analyte capture rates. We also find that the attractive
electrostatic potential may be balanced by an outward, repulsive electroosmotic
flow (EOF) that can in certain cases conspire with the salt gradient to further
enhance the analyte capture rate.Comment: 10 pages, 6 Figure
The First Korean Case of Cutaneous Lung Tissue Heterotopia
Cutaneous lung tissue heterotopia is a very rare disorder where mature lung tissues develop in the skin. This is only the second known report of cutaneous lung tissue heterotopia, with the first by Singer et al. in 1998. A newborn infant had a hemangioma-like, freely movable mass connected to the anterior aspect of the sternal manubrium. Pathologic findings showed mature lung tissues with bronchi, bronchioles, and alveoli through the dermis and subcutis, and it was diagnosed as cutaneous lung tissue heterotopia. Cutaneous lung tissue heterotopia is hypervascular, so grossly it looks like a hemangioma. It can be differentiated from pulmonary sequestration, teratoma, bronchogenic cyst, and branchial cleft cyst by histology and the location of the mass. We describe the clinical, radiologic, and pathologic findings of a cutaneous lung tissue heterotopia, the first reported in Korea
Is early center-based child care associated with tantrums and unmanageable behavior over time up to school entry?
Background. Existing research suggests that there is a relationship between greater exposure to center-based child care and child behavioral problems though the mechanism for the impact is unclear. However the measure used to document child care has usually been average hours, which may be particularly unreliable in the early months when fewer children are in center care. In addition individual trajectories for behavior difficulties have not been studied.
Objective. The purpose of the current study was to examine whether the extent of exposure to center-based child care before two years predicted the trajectory of childrenβs difficult behavior (i.e., tantrums and unmanageable behavior) from 30 to 51 months controlling for child and maternal characteristics.
Method. Data were drawn from UK-based Families, Children and Child Care (FCCC) study (n=1201). Individual growth models were fitted to test the relation between early center-based child care experiences and subsequent difficult behavior.
Results. Children with more exposure to center-based care before two had less difficult behavior at 30 months, but more increase over time. Initial levels were predicted by higher difficult temperament and lower verbal ability. Higher difficult temperament and lower family socio-economic status predicted its change over time.
Conclusion. Findings suggest that early exposure to center-based care before two years old is a risk factor for subsequent behavior problems especially when children have a longer period of exposure. A possible explanatory process is that child coping strategies to manage frustration are less well developed in a group context, especially when they lag behind in expressive language
Correlation functions quantify super-resolution images and estimate apparent clustering due to over-counting
We present an analytical method to quantify clustering in super-resolution
localization images of static surfaces in two dimensions. The method also
describes how over-counting of labeled molecules contributes to apparent
self-clustering and how the effective lateral resolution of an image can be
determined. This treatment applies to clustering of proteins and lipids in
membranes, where there is significant interest in using super-resolution
localization techniques to probe membrane heterogeneity. When images are
quantified using pair correlation functions, the magnitude of apparent
clustering due to over-counting will vary inversely with the surface density of
labeled molecules and does not depend on the number of times an average
molecule is counted. Over-counting does not yield apparent co-clustering in
double label experiments when pair cross-correlation functions are measured. We
apply our analytical method to quantify the distribution of the IgE receptor
(Fc{\epsilon}RI) on the plasma membranes of chemically fixed RBL-2H3 mast cells
from images acquired using stochastic optical reconstruction microscopy (STORM)
and scanning electron microscopy (SEM). We find that apparent clustering of
labeled IgE bound to Fc{\epsilon}RI detected with both methods arises from
over-counting of individual complexes. Thus our results indicate that these
receptors are randomly distributed within the resolution and sensitivity limits
of these experiments.Comment: 22 pages, 5 figure
Modulating signaling networks by CRISPR/Cas9-mediated transposable element insertion
In a recent past, transposable elements (TEs) were referred to as selfish genetic components only capable of copying themselves with the aim of increasing the odds of being inherited. Nonetheless, TEs have been initially proposed as positive control elements acting in synergy with the host. Nowadays, it is well known that TE movement into host genome comprises an important evolutionary mechanism capable of increasing the adaptive fitness. As insights into TE functioning are increasing day to day, the manipulation of transposition has raised an interesting possibility of setting the host functions, although the lack of appropriate genome engineering tools has unpaved it. Fortunately, the emergence of genome editing technologies based on programmable nucleases, and especially the arrival of a multipurpose RNA-guided Cas9 endonuclease system, has made it possible to reconsider this challenge. For such purpose, a particular type of transposons referred to as miniature inverted-repeat transposable elements (MITEs) has shown a series of interesting characteristics for designing functional drivers. Here, recent insights into MITE elements and versatile RNA-guided CRISPR/Cas9 genome engineering system are given to understand how to deploy the potential of TEs for control of the host transcriptional activity.Fil: Vaschetto, Luis Maria Benjamin. Consejo Nacional de Investigaciones CientΓficas y TΓ©cnicas. Centro CientΓfico TecnolΓ³gico Conicet - CΓ³rdoba. Instituto de Diversidad y EcologΓa Animal. Universidad Nacional de CΓ³rdoba. Facultad de Ciencias Exactas FΓsicas y Naturales. Instituto de Diversidad y EcologΓa Animal; Argentina. Universidad Nacional de CΓ³rdoba. Facultad de Ciencias Exactas, FΓsicas y Naturales. CΓ‘tedra de Diversidad Animal I; Argentin
Clinical Significance of Microsatellite Instability in Sporadic Epithelial Ovarian Tumors
PURPOSE: We evaluated the expression of microsatellite instability (MSI) in sporadic ovarian tumors using 5 standard and 9 new MSI markers to determine the clinical significance of MSI in sporadic epithelial ovarian tumors.
MATERIALS AND METHODS: MSI was examined in 21 borderline and 25 malignant ovarian tumors. Polymerase chain reaction (PCR) was performed using the 5 markers recommended by the National Cancer Institute (NCI) for colon cancer and 9 additional markers. MSI was determined using fractional analysis by mixing the PCR products and size markers.
RESULTS: Using the 5 conventional MSI markers, MSI was found in 4 of 46 (8.6%) ovarian tumors, including 2 of 21 (9.5%) borderline ovarian tumors and 2 of 25 (8%) malignant ovarian tumors. Using the 9 additional MSI markers, MSI was observed in 7 of 46 (15.2%) ovarian tumors, including 3 of 21 (14.3%) borderline ovarian tumors and 4 of 25 (16%) malignant ovarian tumors. There was no statistically significant difference between MSI and clinicopathological factors, including histology and stage, although there was a trend toward an increased incidence of MSI in the serous type.
CONCLUSION: MSI was infrequent in ovarian tumors, including both borderline and malignant tumors. MSI was found to be uncommon in sporadic ovarian tumors, even by using additional MSI markers. The clinical significance of MSI is not strong in patients with sporadic ovarian tumors.ope
Determining the neurotransmitter concentration profile at active synapses
Establishing the temporal and concentration profiles of neurotransmitters during synaptic release is an essential step towards understanding the basic properties of inter-neuronal communication in the central nervous system. A variety of ingenious attempts has been made to gain insights into this process, but the general inaccessibility of central synapses, intrinsic limitations of the techniques used, and natural variety of different synaptic environments have hindered a comprehensive description of this fundamental phenomenon. Here, we describe a number of experimental and theoretical findings that has been instrumental for advancing our knowledge of various features of neurotransmitter release, as well as newly developed tools that could overcome some limits of traditional pharmacological approaches and bring new impetus to the description of the complex mechanisms of synaptic transmission
Practitioner review: Treatments for Tourette syndrome in children and young people: a systematic review
Background:
Tourette syndrome (TS) and chronic tic disorder (CTD) affect 1β2% of children and young people, but the most effective treatment is unclear. To establish the current evidence base, we conducted a systematic review of interventions for children and young people.
Methods:
Databases were searched from inception to 1 October 2014 for placebo-controlled trials of pharmacological, behavioural, physical or alternative interventions for tics in children and young people with TS or CTD. Certainty in the evidence was assessed with the GRADE approach.
Results:
Forty trials were included [pharmacological (32), behavioural (5), physical (2), dietary (1)]. For tics/global score there was evidence favouring the intervention from four trials of a2-adrenergic receptor agonists [clonidine and guanfacine, standardised mean difference (SMD) = -0.71; 95% CI -1.03, -0.40; N = 164] and two trials of habit reversal training (HRT)/comprehensive behavioural intervention (CBIT) (SMD = -0.64; 95% CI -0.99, -0.29; N = 133). Certainty in the effect estimates was moderate. A post hoc analysis combining oral clonidine/guanfacine trials with a clonidine patch trial continued to demonstrate benefit (SMD = -0.54; 95% CI -0.92, -0.16), but statistical heterogeneity was high. Evidence from four trials suggested that antipsychotic drugs improved tic scores (SMD = -0.74; 95% CI -1.08, -0.40; N = 76), but certainty in the effect estimate was low. The evidence for other interventions was categorised as low or very low quality, or showed no conclusive benefit.
Conclusions:
When medication is considered appropriate for the treatment of tics, the balance of clinical benefits to harm favours a2-adrenergic receptor agonists (clonidine and guanfacine) as first-line agents. Antipsychotics are likely to be useful but carry the risk of harm and so should be reserved for when a2-adrenergic receptor agonists are either ineffective or poorly tolerated. There is evidence that HRT/CBIT is effective, but there is no evidence for HRT/CBIT alone relative to combining medication and HRT/CBIT. There is currently no evidence to suggest that the physical and dietary interventions reviewed are sufficiently effective and safe to be considered as treatments
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