318 research outputs found
On cubic graphs having the maximal coalition number
A coalition in a graph with vertex set consists of two disjoint sets
such that neither nor is a dominating set, but
the union is a dominating set in . A partition of graph
vertices is called a coalition partition if every non-dominating
set of is a member of a coalition and every dominating set is a
single-vertex set. The coalition number of a graph is the maximum
cardinality of its coalition partition. It is known that for cubic graphs
. The existence of cubic graphs with the maximal coalition number is
an unsolved problem. In this paper, an infinite family of cubic graphs
satisfying is constructed
Purification of immature neuronal cells from neural stem cell progeny
Large-scale proliferation and multi-lineage differentiation capabilities make neural stem cells (NSCs) a promising renewable source of cells for therapeutic applications. However, the practical application for neuronal cell replacement is limited by heterogeneity of NSC progeny, relatively low yield of neurons, predominance of astrocytes, poor survival of donor cells following transplantation and the potential for uncontrolled proliferation of precursor cells. To address these impediments, we have developed a method for the generation of highly enriched immature neurons from murine NSC progeny. Adaptation of the standard differentiation procedure in concert with flow cytometry selection, using scattered light and positive fluorescent light selection based on cell surface antibody binding, provided a near pure (97%) immature neuron population. Using the purified neurons, we screened a panel of growth factors and found that bone morphogenetic protein-4 (BMP-4) demonstrated a strong survival effect on the cells in vitro, and enhanced their functional maturity. This effect was maintained following transplantation into the adult mouse striatum where we observed a 2-fold increase in the survival of the implanted cells and a 3-fold increase in NeuN expression. Additionally, based on the neural-colony forming cell assay (N-CFCA), we noted a 64 fold reduction of the bona fide NSC frequency in neuronal cell population and that implanted donor cells showed no signs of excessive or uncontrolled proliferation. The ability to provide defined neural cell populations from renewable sources such as NSC may find application for cell replacement therapies in the central nervous system
Comparative Analysis of the Frequency and Distribution of Stem and Progenitor Cells in the Adult Mouse Brain
cells (NSCs) and progenitor cells, but it cannot discriminate
between these two populations. Given two assays
have purported to overcome this shortfall, we performed
a comparative analysis of the distribution and frequency
of NSCs and progenitor cells detected in 400 m coronal
segments along the ventricular neuraxis of the adult
mouse brain using the neurosphere assay, the neural
colony forming cell assay (N-CFCA), and label-retaining
cell (LRC) approach. We observed a large variation in the
number of progenitor/stem cells detected in serial sections
along the neuraxis, with the number of neurosphereforming
cells detected in individual 400 m sections varying
from a minimum of eight to a maximum of 891
depending upon the rostral-caudal coordinate assayed.
Moreover, the greatest variability occurred in the rostral
portion of the lateral ventricles, thereby explaining the
large variation in neurosphere frequency previously reported.
Whereas the overall number of neurospheres
(3730 276) or colonies (4275 124) we detected along
the neuraxis did not differ significantly, LRC numbers
were significantly reduced (1186 188, 7 month chase) in
comparison to both total colonies and neurospheres.
Moreover, approximately two orders of magnitude fewer
NSC-derived colonies (50 10) were detected using the
N-CFCA as compared to LRCs. Given only 5% of the
LRCs are cycling (BrdU/Ki-67) or competent to divide
(BrdU/Mcm-2), and proliferate upon transfer to culture,
it is unclear whether this technique selectively detects
endogenous NSCs. Overall, caution should be taken
with the interpretation and employment of all these techniques
A multi-depot location routing problem to reduce the differences between the vehicles’ traveled distances; a comparative study of heuristics
Study of clonal variation of 'Bidaneh Ghermez' grapevine cultivar in Iran
ArticleGrapevine (Vitis vinifera L.) is a well
- known plant including different cultivars and
clones. In spite of the extensive works at the cultivar level, identification and determination of
clonal genetic variation has remained as a challenge. To assess the genetic variation between clones of grapevine cv. 'Bidaneh Ghermez', 20 selected clones were analyzed for cluster weight (CW), cluster length (CL), cluster width (CWI), berry weight (BW), berry length (BL), berry width (BWI) and total soluble solids (TSS) in randomized complete block design with three replications. Analysis of variance reveale
d considerable genetic variation for all measured traits (except cluster width) among clones. Cluster analysis, discriminant function analysis and principal component analysis (PCA) showed same results and all clones assigned in 2 groups. First group was including 9 clones and second group was including 11 clones. Overall, our results
indicated C7, C10, C12 and C14 clones were best clones and have potential to introduce promising clones for stablishing new vineyard with high yield
Cinnamon Essential Oil Encapsulated into a Fish Gelatin-Bacterial Cellulose Nanocrystals Complex and Active Films Thereof
In this study, cinnamon essential oil (CEO) nanocapsules were stabilized by means of bacterial cellulose nanocrystals (BCNCs) and encapsulated using fish gelatin as the main polymer phase. Emulsions were prepared at pH 5 using different CEO concentrations (0.03, 0.06, 0.12, 0.24, 0.36, and 0.48% v/w) and a fixed amount of fish gelatin (3% w/w) and BCNCs (0.06% w/w). The controlled release of the essential oil was assessed by release studies, which revealed that the higher the CEO concentration, the lower the release rate of CEO. In addition, modelling of experimental data using five different equations showed that the best fitting was obtained for the Korsmeyer-Peppas model, according to which the CEO release obeyed a non-Fickian behavior. Films obtained from the same formulations were characterized in terms of optical properties (light transmittance and haze), surface wettability, barrier (oxygen, carbon dioxide, and water vapor transmission rates) and mechanical properties. It was observed that an increased amount of CEO in the films did not significantly affect both transparency and haze, while it yielded an increase in surface hydrophobicity (~ 120% increase in water contact angle over the control) and elongation. Finally, the barrier performances of films against O2, CO2, and water vapor suggest a potential application of CEO/GelA-BCNC matrices as antimicrobial layers (in the form of coatings deposited on plastic films or directly on food) in living foods that have a respiratory metabolism, such as modified atmosphere-packaged crustaceans and mollusks as well as fruits and vegetables. Graphical abstract: [Figure not available: see fulltext.
Topographical analysis of the subependymal zone neurogenic niche
The emerging model for the adult subependymal zone (SEZ) cell population indicates that neuronal diversity is not generated from a uniform pool of stem cells but rather from diverse and spatially confined stem cell populations. Hence, when analysing SEZ proliferation, the topography along the anterior-posterior and dorsal-ventral axes must be taken into account. However, to date, no studies have assessed SEZ proliferation according to topographical specificities and, additionally, SEZ studies in animal models of neurological/psychiatric disorders often fail to clearly specify the SEZ coordinates. This may render difficult the comparison between studies and yield contradictory results. More so, by focusing in a single spatial dimension of the SEZ, relevant findings might pass unnoticed. In this study we characterized the neural stem cell/progenitor population and its proliferation rates throughout the rat SEZ anterior-posterior and dorsal-ventral axes. We found that SEZ proliferation decreases along the anterior-posterior axis and that proliferative rates vary considerably according to the position in the dorsal-ventral axis. These were associated with relevant gradients in the neuroblasts and in the neural stem cell populations throughout the dorsal-ventral axis. In addition, we observed spatially dependent differences in BrdU/Ki67 ratios that suggest a high variability in the proliferation rate and cell cycle length throughout the SEZ; in accordance, estimation of the cell cycle length of the neuroblasts revealed shorter cell cycles at the dorsolateral SEZ. These findings highlight the need to establish standardized procedures of SEZ analysis. Herein we propose an anatomical division of the SEZ that should be considered in future studies addressing proliferation in this neural stem cell niche.Fundação para a Ciência e a Tecnologia (FCT
Comparison of serum zinc in children younger than 5 years old with febrile convulsion, children with seizures without fever and normal children
Background: Febrile seizures are the most common seizure disorder in children and have a good prognosis. Many theories about the role of neurotransmitters and trace elements in serum and cerebrospinal fluid are introduced as the pathogenesis of febrile seizures. Among these elements, the element can be noted. The purpose of this study to comparison of serum zinc in children younger than 5 years old with febrile convulsion, children with seizures without febrile and normal children.Methods: In this study, 180 children were studied in three groups. 60 children with seizures without fever and 60 children with febrile convulsions admitted to hospital and 60 healthy children without a history of seizures. Afzalipour who were referred to health centers in the city of Kerman. Serum zinc levels in all three groups were measured by atomic absorption spectrophotometry.Results: The mean serum zinc levels in children with febrile seizures in this investigation was 48.4 µg/dl, compared with the other two tense children without fever (64.61 µg/dl) and healthy children (67.33 µg/dl) was significantly lower.Conclusion:Results of this study showed reduced serum zinc levels during febrile seizure. The need for continued research on surface tension in febrile children over several months is recommended.
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