Understanding the plasmonic properties of dewetting formed Ag nanoparticles for large area solar cell applications

Cataloged from PDF version of article.The effects of substrates with technological interest for solar cell industry are examined on the plasmonic properties of Ag nanoparticles fabricated by dewetting technique. Both surface matching (boundary element) and propagator (finite difference time domain) methods are used in numerical simulations to describe plasmonic properties and to interpret experimental data. The uncertainty on the locations of nanoparticles by the substrate in experiment is explained by the simulations of various Ag nanoparticle configurations. The change in plasmon resonance due to the location of nanoparticles with respect to the substrate, interactions among them, their shapes, and sizes as well as dielectric properties of substrate are discussed theoretically and implications of these for the experiment are deliberated. (C) 2013 Optical Society of Americ

The electrochemistry of iron oxide thin films nanostructured by high ion flux plasma exposure

Photo-electrochemical (PEC) water splitting of hematite photoanodes suffers from low performance and efficiency. One way to increase the performance is to increase the electrochemically active surface area available for the oxygen evolution reaction. In this study, we use high ion flux, low energy helium plasma exposure to nanostructure sputtered iron thin films. Subsequent annealing in air at 645&nbsp;°C leads to the formation of PEC active hematite (α-Fe2O3) phase in these films. The surface area, as derived from electrochemical impedance spectroscopy (EIS), was seen to increase 10–40 times with plasma exposure. The photocurrent density increased by 2–5 times for the plasma exposed films as compared to the unexposed films. However, the less nanostructured film showed a higher photocurrent density. These findings were explained by detailed chemical and structural characterization in combination with electrochemical characterization and attributed to the presence of secondary elements in the film as well as to the presence of secondary iron oxide phases apart from hematite. This work demonstrates the complex effect of plasma exposure on both film morphology and chemical composition of PEC thin films and provides further understanding on how this technique can be used for nanostructuring of other functional films.</p

Myelodysplastic syndrome in childhood [Çocukluk çaginda miyelodisplastik sendrom]

Myelodysplastic syndrome (MDS) constitutes 1-16% percent of haematological malignancies in childhood and is more frequently seen between two and four years of age. There are differences between pediatric and adult MDS. RA and RARS are very rare in childhood, while RAEB and RAEBt are most frequently seen. It is very difficult to diagnose childhood MDS. However, there has been an increasing number of reports during the last decades on childhood MDS owing to the better recognition of the disease. Recently, because of inadequacy of classic FAB classification, WHO has offered a new classification of pediatric MDS, at its last meeting in 2002. Cytogenetic abnormalities are frequently seen in MDS such as monosomy 7. The median survival time was 13 months and the survival rate for three years from the establishment of diagnosis was 16%. The clinical and laboratory findings of MDS are similar to many other diseases, thus delayed diagnosis and treatment can lead to increased mortality. Though the only successful treatment is stem cell transplantation, difficulties in getting a right donor and thus time lapsed leads to higher mortality. We presented this review article to attract your attention to this topic

Incidence and prognostic importance of molecular genetic defects in children with acute myeloblastic leukemia

Introduction: Acute myeloblastic leukemia (AML) accounts for 15 to 25 percent of childhood acute leukemias. The most common genetic abnormalities seen in pediatric AML patients are AML1-ETO, PML-RAR? and CBFB-MYH11 genes resulting in t(8;21), t(15;17) and inv(16). These genetic defects are seen in approximately 20-25% of AML patients. Objective: We investigated in this study, incidence and prognostic significance of the AML1-ETO, PML-RAR? and CBFB-MYH11 genes in children with AML. Materials and Methods: The authors analyzed 34 children with AML using the real time-polymerase chain reaction for AML1-ETO, PML-RAR? and CBFB-MYH11 genes. Results: Of the patients, 8.8% were positive for t(8;21), 8.8% for t(15;17) and 3% for inv(16). There were a statistically significant differences between 48 month overall survival rates of the patients positive and negative for t(8;21), t(15;17) and inv(16). Conclusion: It was concluded that t(15;17), t(8;21) and inv(16) impact on disease prognosis positively, but comprehensive studies with larger patient series are now needed for confirmation

Brain natriuretic peptide levels in pediatric cancer patients with febrile neutropenia

PubMedID: 21413834Brain natriuretic peptide (BNP) is considered as a prognostic marker in patients with sepsis, but no data are available on BNP in pediatric cancer patients with febrile neutropenia (FN). Twenty-five pediatric cancer patients with FN were included in this study. Serum BNP level was measured. The mean BNP level was 330.8 ± 765.3 pg/mL (5.9-3806 pg/mL). BNP levels of 12 patients were found over the normal level. High BNP levels were related to some conditions of the patients, and these were statistically significant (P < .05). These conditions were required erythrocyte suspension, had pneumonia, time stayed in hospital, and neutropenia time. When regression test was done, required erythrocyte suspension for anemia and had pneumonia were found to be statistically significant. In conclusion, this is one of the first studies on BNP levels in pediatric cancer patients with FN. However, further studies with large sample sizes are needed to confirm the results and provide new data about this issue. © 2011 Informa Healthcare USA, Inc

Meropenem monotherapy as an empirical treatment of febrile neutropenia in childhood cancer patients

PubMedID: 20593941Introduction: Chemotherapy related neutropenia developing in oncologic patients is a significant condition and major cause of morbidity and mortality. Febrile neutropenic attacks without complications can be successfully treated with wide-spectrum anti-pseudomonal cephalosporins or carbapenems. Objective: We investigated the efficacy and safety of meropenem in the treatment of febrile neutropenia (FN) in children with cancer. Materials and Methods: Twenty four patients who had a febrile neutropenic episodes followed by initiation of empirical meropenem therapy were included in the study. Results: Of all the patients, 13 (54.2%) had solid tumors, while 11 (45.8%) were diagnosed to have acute leukemia. Among all, 7 (29.2%) and 15 (62.5%) infections were identified microbiologically and clinically, respectively. Fever of unknown origin was observed in 2 (8.3%) patients. The mean duration of neutropenia was 7.2 ± 3.1 (4-14) days in patients with solid tumors, and 9.3 ± 4.7 (2-17) days in the group with leukemia. This difference was not statistically significant (log rank, p=0.063). Average time of stay in hospital was 10.1 ± 6.4 (4-21) days for patients with solid tumors, and 15.9 ± 11.7 (5-37) days for patients with leukemia (log rank, p=0.041). FN duration was observed to be significantly longer in patients with an absolute neutrophil count (ANC) of less than 100/mm3 and even those with an ANC of less than 200/mm3, and in children who were not in remission for the underlying malign disease (p<0.05). While 22 (91.7%) of the patients were discharged from the hospital, 2 (8.3%) died. The success rate of empirical therapy started with meropenem was 87.5%. Conclusion: Meropenem is effective and safe for treatment of FN in pediatric cancer patients

Screening of entomopathogenic fungi against the European spruce bark beetle, Dendroctonus micans (Coleoptera: Scolytidae)

The European spruce bark beetle, Dendroctonus micans Kugelann (Coleoptera: Scolytidae), is one of the most serious destructive pests of oriental spruce (Picea orientalis L.). In order to find an effective biocontrol agent against this pest, we determined the effectiveness of entomopathogenic fungi against D. micans. Virulence of nine highly pathogenic strains including Beauveria bassiana (2), Beauveria cf. bassiana (2), Metarhizium anisopliae (2), Metarhizium sp. (1), Isaria fumosorosea (1) and Evlachovaea sp. (1) was evaluated on D. micans larvae and adults under laboratory conditions. Mortality values for both larvae and adults ranged from 83 to 100% and from 23 to 100%, respectively. Larvae were more susceptible to fungi than adults (P<0.05). Based on screening tests, B. cf. bassiana isolate KTU-53 was found the most effective isolate. LC50 values were calculated as 1.77×104 and 2.65×104 conidia mL-1 for isolate KTU-53 against larvae and adults, respectively. Consequently, B. cf. bassiana isolate KTU-53 appears to be the most promising microbial control agent for biocontrol of D. micans. © 2010 Taylor & Francis