In the present work the silica-based matrix effect on the luminescence properties of the nanocomposites which contain cadmium sulfide quantum dots (CdS QDs) was studied. Water alkaline solution of ...sodium silicates Na2O(SiO2)n, or liquid glass, or tetraethyl orthosilicate (TEOS) were used as simple models of a dielectric matrix. The synthesis of nanocomposites by sol-gel method using liquid glass and TEOS was carried out in two ways: mixing the prepared colloidal solution of nanoparticles with silica precursor or synthesis of nanoparticles directly in the matrix. The composite based on CdS QDs in a more complex matrix of silicate glass was also studied. The optical absorption and luminescence were studied in detail depending on the synthesis method. It was shown that various atomic defects contribute predominantly to the luminescence of QDs formed in different matrices, the matrix affects on the formation of the defects, therefore the luminescence range. In addition it was shown that method of synthesis affected the intensity of luminescence.
Display omitted
•Nanocomposites with CdS QDs in three silica-based matrix were prepared.•The silicate glass, liquid glass and TEOS were used.•Luminescence of CdS QDs is strong traps depended.•The energy levels and atomic defect contributions to the luminescent spectra are vary in different matrixes.•Main defects in glass/CdS are VCd, Is; in TEOS/CdS – Is, VCd, Vs; in liquid glass/CdS – Is, VCd, Vs.
The use of machine learning to develop neural network potentials (NNP) representing the interatomic potential energy surface allows us to achieve an optimal balance between accuracy and efficiency in ...computer simulation of materials. A key point in developing such potentials is the preparation of a training dataset of ab initio trajectories. Here we apply a deep potential molecular dynamics (DeePMD) approach to develop NNP for silica, which is the representative glassformer widely used as a model system for simulating network-forming liquids and glasses. We show that the use of a relatively small training dataset of high-temperature ab initio configurations is enough to fabricate NNP, which describes well both structural and dynamical properties of liquid silica. In particular, we calculate the pair correlation functions, angular distribution function, velocity autocorrelation functions, vibrational density of states, and mean-square displacement and reveal a close agreement with ab initio data. We show that NNP allows us to expand significantly the time-space scales achievable in simulations and thus calculating dynamical and transport properties with more accuracy than that for ab initio methods. We find that developed NNP allows us to describe the structure of the glassy silica with satisfactory accuracy even though no low-temperature configurations were included in the training procedure. The results obtained open up prospects for simulating structural and dynamical properties of liquids and glasses via NNP.
Fathers influence mothers’ breastfeeding decisions and experiences. Fathers’ perceptions of their roles as members of the breastfeeding family are likely important components of that influence. To ...explore that possibility, 21 involved fathers of breastfeeding babies volunteered to be interviewed regarding their fathering breastfed babies and their roles in the breastfeeding family. Fathers identified their unique roles as team members ensuring that their babies received the benefits of breastfeeding. A primary fathering role was that of supporting breastfeeding by becoming breastfeeding savvy, by using their knowledge to encourage and assist mothers in breastfeeding, by valuing the breastfeeding mothers, and by sharing housework and child care. Fathers’ nurturing roles involved fostering positive father-infant relationships in the face of limited opportunities to bond with their babies through feeding. The experiences of these fathers suggest the importance of assisting them to recognize their unique contributions to the nurture of their children as members of the breastfeeding team.
The results of recent experimental studies of the influence of the size of oxide, carbide and sulfide nanoparticles on changes in their nonstoichiometry are analyzed and generalized. In relation to ...intrinsically nonstoichiometric titanium oxides and niobium and vanadium carbides, on the one hand, and stoichiometric silver sulfides, on the other hand, it is shown that a decrease in the particle size to the nano scale has a strong impact on the chemical composition of nanocrystalline compounds,
viz
., it leads to the occurrence of or increase in nonstoichiometry. A conclusion is drawn that interplay between the particle size and nonstoichiometry is common to all solid nanocrystalline substances and should be taken into account in studies on the synthesis, structure and properties of these systems.
The bibliography includes 260 references.
The crystal structure and microstructure of pseudobinary (ZrC
0.96
)
1−
x
(NbC
0.97
)
x
carbide solid solutions has been studied. It was found that monocrystalline grains of zirconium carbide are ...spontaneously isolated on the surface of diluted solid solutions of the pseudobinary system ZrC
y
-NbC
y
′
containing less than 2.0 mol% of zirconium carbide. It is shown that the appearance of zirconium carbide is a consequence of the solid-phase decomposition of these solid solutions and anisotropy of elastic properties of monocrystalline ZrC carbide grains. The model of subregular solutions was used in the temperature interval from 300 to 3900 K to calculate and plot an equilibrium phase diagram of the ternary Zr-Nb-C system. It is shown that at temperatures above 1210 K in the Zr-Nb-C ternary system, nonstoichiometric carbides ZrC
y
and NbC
y
′
have unlimited mutual solubility and form a continuous series of (ZrC
y
)
1−
x
(NbC
y
′
)
x
solid solutions with 0.6 ≤
y
≤ 0.98, 0.7 ≤
y
′ ≤ 1.0, and 0 ≤
x
≤ 1.0. At temperatures below 1200 K, under equilibrium conditions, a discontinuity of the miscibility of the solid solutions ZrC
y
-NbC
y
′
is observed and there appears a region of solid phase decomposition. The anisotropy of elastic properties of monocrystalline grains of ZrC was considered. It is predicted that solid-phase decomposition and surface segregation can be observed in such related carbide systems as HfC
y
-NbC
y
′
, HfC
y
-TaC
y
′
, ZrC
y
-TaC
y
′
, VC
y
-TaC
y
′
and VC
y
-NbC
y
′
.
Surface segregation of ZrC in the ZrC-NbC system is connected with low-temperature solid-phase decomposition and anisotropy of ZrC elastic properties.
Fathers' support can influence mothers' breastfeeding decisions and behavior. Potentially supportive behaviors have been reported in previous studies, but no studies have directly examined which, if ...any, of those actions are actually more likely to result in desired breastfeeding outcomes. The two studies reported in this paper address this gap by examining relationships between fathers' reported breastfeeding support and mothers' perceptions of received support and breastfeeding intentions, satisfaction, and duration. The Partner Breastfeeding Influence Scale (PBIS) was used in an online survey with 64 women and 41 men (34 couples) and a telephone survey with 80 mothers and 65 fathers (63 couples). Fathers' and mothers' reports of how often fathers engage in the types of support measured by the PBIS were used to predict breastfeeding intentions, satisfaction, and duration. In Study 1, responsiveness predicted breastfeeding success and satisfaction for men and satisfaction for women. However, mothers' intended breastfeeding duration was shorter when fathers both wanted them to breastfeed for a long time and were more appreciative and savvy about breastfeeding. In Study 2, when fathers reported being more appreciative and directly involved in breastfeeding, mothers reported shorter breastfeeding duration. In both studies, mothers' perceptions of their partners' responsiveness and fathers' reports of their own responsiveness predicted longer breastfeeding intentions and duration. These findings suggest that the most effective breastfeeding support is delivered using a sensitive, coordinated teamwork approach that is responsive to the mother's needs.
Space heating is the single greatest source of building-related greenhouse gas emissions in the industrialized world, giving urgency to the development of strategies for carbon-free heating. Recent ...advances have shown that the direct capture, storage, and deployment of solar energy, without conversion to electricity, has considerable potential to address space-heating needs even in cold and cloudy climates. However, the solar energy available for direct heating at climatic and metropolitan scales is both unquantified and widely assumed to be negligible, impeding further investigation, development, and policy responses. To estimate the magnitude and distribution of solar resources concurrent with space-heating needs, we spatially integrate datasets characterizing solar radiation, outdoor temperature, and heating energy use across U.S. climates. Results show that the median resource incident upon collectors of residential scale (10m2) and distribution is much greater than previously realized, equaling 7MWh per household annually; by comparison, the median household heating need is currently 10.3MWh. Unexpectedly, cloud-diffused solar radiation accounts for over one-quarter of this resource in all but semi-arid climates. Metropolitan residential resources exceed 5TWh in areas including Detroit and Boston (cold continental), WashingtonD.C. (humid subtropical), Seattle and San Francisco (Mediterranean), and Denver (semi-arid), and national resources exceed 750TWh annually, compared to approximately 1200TWh of annual heating need. Current technology is able to capture and retain over half of a direct solar heating resource, revealing that the untapped U.S. solar heating potential is comparable to one-third of the national residential space-heating need and implying that analogous resources exist in analogous climates worldwide.
•Solar energy resources for direct space heating are estimated for the first time.•Resources are extensive in cool, cold, and cloudy climates.•Diffuse radiation is often a sizable resource component, requiring tilted collectors.•The median U.S. household direct solar heating resource exceeds 7MWh annually.•The untapped U.S. solar heating potential equals one-third of residential needs.
Mega-earthquakes rupture flat megathrusts Bletery, Quentin; Thomas, Amanda M.; Rempel, Alan W. ...
Science (American Association for the Advancement of Science),
11/2016, Letnik:
354, Številka:
6315
Journal Article
Recenzirano
Odprti dostop
The 2004 Sumatra-Andaman and 2011 Tohoku-Oki earthquakes highlighted gaps in our understanding of mega-earthquake rupture processes and the factors controlling their global distribution: A fast ...convergence rate and young buoyant lithosphere are not required to produce mega-earthquakes. We calculated the curvature along the major subduction zones of the world, showing that mega-earthquakes preferentially rupture flat (low-curvature) interfaces. A simplified analytic model demonstrates that heterogeneity in shear strength increases with curvature. Shear strength on flat megathrusts is more homogeneous, and hence more likely to be exceeded simultaneously over large areas, than on highly curved faults.
Glioblastomas (GBM), the most common and aggressive type of malignant glioma, are characterized by increased invasion into the surrounding brain tissues. Despite intensive therapeutic strategies, the ...median survival of GBM patients has remained dismal over the last decades. In this study we examined the expression of miR-145 in glial tumors and its function in glioma cells. Using TCGA analysis and real-time PCR we found that the expression of miR-145/143 cluster was downregulated in astrocytic tumors compared to normal brain specimens and in glioma cells and glioma stem cells (GSCs) compared to normal astrocytes and neural stem cells. Moreover, the low expression of both miR-145 and miR-143 in GBM was correlated with poor patient prognosis. Transfection of glioma cells with miR-145 mimic or transduction with a lentivirus vector expressing pre-miR 145 significantly decreased the migration and invasion of glioma cells. We identified connective tissue growth factor (CTGF) as a novel target of miR-145 in glioma cells; transfection of the cells with this miRNA decreased the expression of CTGF as determined by Western blot analysis and the expression of its 3'-UTR fused to luciferase. Overexpression of a CTGF plasmid lacking the 3'-UTR and administration of recombinant CTGF protein abrogated the inhibitory effect of miR-145 on glioma cell migration. Similarly, we found that silencing of CTGF decreased the migration of glioma cells. CTGF silencing also decreased the expression of SPARC, phospho-FAK and FAK and overexpression of SPARC abrogated the inhibitory effect of CTGF silencing on cell migration. These results demonstrate that miR-145 is downregulated in glial tumors and its low expression in GBM predicts poor patient prognosis. In addition miR-145 regulates glioma cell migration by targeting CTGF which downregulates SPARC expression. Therefore, miR-145 is an attractive therapeutic target for anti-invasive treatment of astrocytic tumors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We examined the extent to which fathers can be taught and encouraged to develop positive relationships with their children, especially in infancy, and the effects of this fathering intervention on ...infant development. A multifaceted relationally focused intervention was used to assist fathers in Vietnam to engage in responsive direct and indirect involvement with their infants and work together with the mother as part of a parenting team. Fathers and mothers from 13 communes in a rural and semiurban district were recruited to the intervention group. Intervention fathers received group and individual counseling before and after birth, an interactive print resource, community messages about fathering, and the opportunity to participate in a Fathers Club. Couples from 12 comparable communes in a noncontiguous district were recruited to the control group. Fathers and mothers completed questionnaires at the prebirth recruitment and at 1-, 4-, and 9-months postbirth. Intervention fathers demonstrated greater increase in knowledge and attitudes regarding father-infant relationships. Both fathers and mothers reported that fathers engaged in more affection, care-taking, and play in the early months of their infants' lives and fathers felt more attached to their infants right from birth. A developmental assessment at 9 months showed that intervention infants demonstrated higher levels of motor, language, and personal/social development. This study demonstrated that fathers can be taught to interact more sensitively, responsively, and effectively with their newborn infants. Their increased interaction and emotional attachment appears to lay the foundation for enhanced infant development.
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