138 research outputs found
Hybrid nanoantennas for directional emission enhancement
Plasmonic and dielectric nanoparticles offer complementary strengths regarding their use as optical antenna elements. While plasmonic nanoparticles are well-known to provide strong decay rate enhancement for localized emitters, all-dielectric nanoparticles can enable high directivity combined with low losses. Here, we suggest a hybrid metal-dielectric nanoantenna consisting of a gold nanorod and a silicon nanodisk, which combines all these advantages. Our numerical analysis reveals a giant enhancement of directional emission together with simultaneously high radiation efficiency (exceeding 70%). The suggested hybrid nanoantenna has a subwavelength footprint, and all parameters and materials are chosen to be compatible with fabrication by two-step electron-beam lithography.The authors acknowledge a support from the Australian
Research Council
Crystallization of Ge2Sb2Te5 thin films by nano- and femtosecond single laser pulse irradiation
The amorphous to crystalline phase transformation of Ge2Sb2Te5 (GST) films by UV nanosecond (ns)
and femtosecond (fs) single laser pulse irradiation at the same wavelength is compared. Detailed
structural information about the phase transformation is collected by x-ray diffraction and high
resolution transmission electron microscopy (TEM). The threshold fluences to induce crystallization
are determined for both pulse lengths. A large difference between ns and fs pulse irradiation was
found regarding the grain size distribution and morphology of the crystallized films. For fs single
pulse irradiated GST thin films, columnar grains with a diameter of 20 to 60 nm were obtained as
evidenced by cross-sectional TEM analysis. The local atomic arrangement was investigated by highresolution
Cs-corrected scanning TEM. Neither tetrahedral nor off-octahedral positions of Ge-atoms
could be observed in the largely defect-free grains. A high optical reflectivity contrast (~25%) between
amorphous and completely crystallized GST films was achieved by fs laser irradiation induced at
fluences between 13 and 16 mJ/cm2 and by ns laser irradiation induced at fluences between 67 and
130 mJ/cm2. Finally, the fluence dependent increase of the reflectivity is discussed in terms of each
photon involved into the crystallization process for ns and fs pulses, respectively
Dihydropyrimidine Dehydrogenase Testing prior to Treatment with 5-Fluorouracil, Capecitabine, and Tegafur: A Consensus Paper
Background: 5-Fluorouracil (FU) is one of the most commonly used cytostatic drugs in the systemic treatment of
cancer. Treatment with FU may cause severe or life-threatening side effects and the treatment-related mortality rate is 0.2–1.0%. Summary: Among other risk factors associated
with increased toxicity, a genetic deficiency in dihydropyrimidine dehydrogenase (DPD), an enzyme responsible for
the metabolism of FU, is well known. This is due to variants
in the DPD gene (DPYD). Up to 9% of European patients carry a DPD gene variant that decreases enzyme activity, and
DPD is completely lacking in approximately 0.5% of patients.
Here we describe the clinical and genetic background and
summarize recommendations for the genetic testing and
tailoring of treatment with 5-FU derivatives. The statement
was developed as a consensus statement organized by the
German Society for Hematology and Medical Oncology in
cooperation with 13 medical associations from Austria, Germany, and Switzerland. Key Messages: (i) Patients should be
tested for the 4 most common genetic DPYD variants before
treatment with drugs containing FU. (ii) Testing forms the
basis for a differentiated, risk-adapted algorithm with recommendations for treatment with FU-containing drugs. (iii)
Testing may optionally be supplemented by therapeutic
drug monitorin
Comprehensive mutation analysis of 17 Y-chromosomal short tandem repeat polymorphisms included in the AmpFlSTR® Yfiler® PCR amplification kit
The Y-chromosomal short tandem repeat (Y-STR) polymorphisms included in the AmpFlSTR® Yfiler® polymerase chain reaction amplification kit have become widely used for forensic and evolutionary applications where a reliable knowledge on mutation properties is necessary for correct data interpretation. Therefore, we investigated the 17 Yfiler Y-STRs in 1,730–1,764 DNA-confirmed father–son pairs per locus and found 84 sequence-confirmed mutations among the 29,792 meiotic transfers covered. Of the 84 mutations, 83 (98.8%) were single-repeat changes and one (1.2%) was a double-repeat change (ratio, 1:0.01), as well as 43 (51.2%) were repeat gains and 41 (48.8%) repeat losses (ratio, 1:0.95). Medians from Bayesian estimation of locus-specific mutation rates ranged from 0.0003 for DYS448 to 0.0074 for DYS458, with a median rate across all 17 Y-STRs of 0.0025. The mean age (at the time of son’s birth) of fathers with mutations was with 34.40 (±11.63) years higher than that of fathers without ones at 30.32 (±10.22) years, a difference that is highly statistically significant (p < 0.001). A Poisson-based modeling revealed that the Y-STR mutation rate increased with increasing father’s age on a statistically significant level (α = 0.0294, 2.5% quantile = 0.0001). From combining our data with those previously published, considering all together 135,212 meiotic events and 331 mutations, we conclude for the Yfiler Y-STRs that (1) none had a mutation rate of >1%, 12 had mutation rates of >0.1% and four of <0.1%, (2) single-repeat changes were strongly favored over multiple-repeat ones for all loci but 1 and (3) considerable variation existed among loci in the ratio of repeat gains versus losses. Our finding of three Y-STR mutations in one father–son pair (and two pairs with two mutations each) has consequences for determining the threshold of allelic differences to conclude exclusion constellations in future applications of Y-STRs in paternity testing and pedigree analyses
The impact of coding germline variants on contralateral breast cancer risk and survival
Evidence linking coding germline variants in breast cancer (BC)-susceptibility genes other than BRCA1, BRCA2, and CHEK2 with contralateral breast cancer (CBC) risk and breast cancer-specific survival (BCSS) is scarce. The aim of this study was to assess the association of protein-truncating variants (PTVs) and rare missense variants (MSVs) in nine known (ATM, BARD1, BRCA1, BRCA2, CHEK2, PALB2, RAD51C, RAD51D, and TP53) and 25 suspected BC-susceptibility genes with CBC risk and BCSS. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with Cox regression models. Analyses included 34,401 women of European ancestry diagnosed with BC, including 676 CBCs and 3,449 BC deaths; the median follow-up was 10.9 years. Subtype analyses were based on estrogen receptor (ER) status of the first BC. Combined PTVs and pathogenic/likely pathogenic MSVs in BRCA1, BRCA2, and TP53 and PTVs in CHEK2 and PALB2 were associated with increased CBC risk [HRs (95% CIs): 2.88 (1.70–4.87), 2.31 (1.39–3.85), 8.29 (2.53–27.21), 2.25 (1.55–3.27), and 2.67 (1.33–5.35), respectively]. The strongest evidence of association with BCSS was for PTVs and pathogenic/likely pathogenic MSVs in BRCA2 (ER-positive BC) and TP53 and PTVs in CHEK2 [HRs (95% CIs): 1.53 (1.13–2.07), 2.08 (0.95–4.57), and 1.39 (1.13–1.72), respectively, after adjusting for tumor characteristics and treatment]. HRs were essentially unchanged when censoring for CBC, suggesting that these associations are not completely explained by increased CBC risk, tumor characteristics, or treatment. There was limited evidence of associations of PTVs and/or rare MSVs with CBC risk or BCSS for the 25 suspected BC genes. The CBC findings are relevant to treatment decisions, follow-up, and screening after BC diagnosis.</p
- …