Engineering of Low-Loss Metal for Nanoplasmonic and Metamaterials Applications

We have shown that alloying a noble metal (gold) with another metal (cadmium), which can contribute two electrons per atom to a free electron gas, can significantly improve the metals optical properties in certain wavelength ranges and make them worse in the other parts of the spectrum. In particular, in the gold-cadmium alloy we have demonstrated a significant expansion of the spectral range of metallic reflectance to shorter wavelengths. The experimental results and the predictions of the first principles theory demonstrate an opportunity for the improvement and optimization of low-loss metals for nanoplasmonic and metamaterials applications.Comment: 14 Pages, 4 figure

The effect of providing a USB syllabus on resident reading of landmark articles

Background: The acquisition of new knowledge is a primary goal of residency training. Retrieving and retaining influential primary and secondary medical literature can be challenging for house officers. We set out to investigate the effect of a Universal Serial Bus (USB) drive loaded with landmark scientific articles on housestaff education in a pilot study. Methods: We created a USB syllabus that contains 187 primary scientific research articles. The electronic syllabus had links to the full-text articles and was organized using an html webpage with a table of contents according to medical subspecialties. We performed a prospective cohort study of 53 house officers in the internal medicine residency program who received the USB syllabus. We evaluated the impact of the USB syllabus on resident education with surveys at the beginning and conclusion of the nine-month study period. Results: All 50 respondents (100%) reported to have used the USB syllabus. The self-reported number of original articles read each month was higher at the end of the nine-month study period compared to baseline. Housestaff rated original articles as being a more valuable educational resource after the intervention. Conclusions: An electronic syllabus with landmark scientific articles placed on a USB drive was widely utilized by housestaff, increased the self-reported reading of original scientific articles and seemed to have positively influenced residents’ attitude toward original medical literature

Stimulated emission of surface plasmon polaritons

We have observed laser-like emission of surface plasmon polaritons (SPPs) decoupled to the glass prism in an attenuated total reflection setup. SPPs were excited by optically pumped molecules in a polymeric film deposited on the top of the silver film. Stimulated emission was characterized by a distinct threshold in the input-output dependence and narrowing of the emission spectrum. The observed stimulated emission and corresponding to it compensation of the metallic absorption loss by gain enables many applications of metamaterials and nanoplasmonic devices.Comment: 8 pages; 3 figure

Arabic text classification using Polynomial Networks

In this paper, an Arabic statistical learning-based text classification system has been developed using Polynomial Neural Networks. Polynomial Networks have been recently applied to English text classification, but they were never used for Arabic text classification. In this research, we investigate the performance of Polynomial Networks in classifying Arabic texts. Experiments are conducted on a widely used Arabic dataset in text classification: Al-Jazeera News dataset. We chose this dataset to enable direct comparisons of the performance of Polynomial Networks classifier versus other well-known classifiers on this dataset in the literature of Arabic text classification. Results of experiments show that Polynomial Networks classifier is a competitive algorithm to the state-of-the-art ones in the field of Arabic text classification

Role of Protein-Protein Bridging Interactions on Cooperative Assembly of DNA-Bound CRP-CytR-CRP Complex and Regulation of the Escherichia Coli CytR Regulon

The unlinked operons that comprise the Escherichia coli CytR regulon are controlled coordinately through interactions between two gene regulatory proteins, the cAMP receptor protein (CRP) and the cytidine repressor (CytR). CytR controls the balance between CRP-mediated recruitment and activation of RNA polymerase and transcriptional repression. Cooperative interactions between CytR, when bound to an operator (CytO) located upstream of a CytR-regulated promoter, and CRP, when bound to flanking tandem promoters, are critical to the regulatory role of CytR. When CytR binds cytidine, cooperativity is reduced resulting in increased transcriptional activity. However, this cytidine-mediated effect varies among promoters, suggesting that coupling between cytidine binding to CytR and CytR−CRP association is sensitive to promoter structure. To investigate the chemical and structural basis for these effects, we investigated how cytidine binding affects association between CytR and CRP in solution and how it affects the binding of CytR deletion mutants lacking the DNA binding HTH domain, with tandem CRP dimers bound to either udpP or deoP2. Deletion mutants that, as we show here, retain the native functions of the allosteric, inducer-binding domain but do not bind DNA were expressed and purified. We refer to these as Core domain. Despite only weak association between CytR and CRP in solution, our results demonstrate the formation of a relatively stable complex in which the Core domain forms a protein bridge between tandem CRP dimers when bound to either udpP or deoP2. The ΔG° for bridge complex formation is about −7.8 kcal/mol. This is well in excess of that required to account for cooperativity (−2.5 to −3 kcal/mol). The bridge complexes are significantly destabilized by cytidine binding, and to the same extent in both promoter complexes (ΔΔG° ≈ +2 kcal/mol). Even with this destabilization, ΔG° for bridge complex formation by cytidine-liganded Core domain is still sufficient by itself to account for cooperativity. These findings demonstrate that direct coupling between cytidine binding to CytR and CytR−CRP association does not account for promoter-specific effects on cooperativity. Instead, cytidine binding must induce a CytR conformation that is more rigid or in some other way less tolerant of the variation in the geometric arrangement of operator sites between different promoters

Lobar lung transplantation from deceased donors: A systematic review

AIM To systematically review reports on deceased-donor-lobar lung transplantation (ddLLTx) and uniformly describe size matching using the donor-to-recipient predicted-total lung-capacity (pTLC) ratio. METHODS We set out to systematically review reports on ddLLTx and uniformly describe size matching using the donor-to-recipient pTLC ratio and to summarize reported one-year survival data of ddLLTx and conventional-LTx. We searched in PubMed, CINAHL via EBSCO, Cochrane Database of Systematic Reviews via Wiley (CDSR), Database of Abstracts of Reviews of Effects via Wiley (DARE), Cochrane Central Register of Controlled Trials via Wiley (CENTRAL), Scopus (which includes EMBASE abstracts), and Web of Science for original reports on ddLLTx. RESULTS Nine observational cohort studies reporting on 301 ddLLTx met our inclusion criteria for systematic review of size matching, and eight for describing one-year-survival. The ddLLTx-group was often characterized by high acuity; however there was heterogeneity in transplant indications and pre-operative characteristics between studies. Data to calculate the pTLC ratio was available for 242 ddLLTx (80%). The mean pTLCratio before lobar resection was 1.25 ± 0.3 and the transplanted pTLCratio after lobar resection was 0.76 ± 0.2. One-year survival in the ddLLTx-group ranged from 50%-100%, compared to 72%-88% in the conventional-LTx group. In the largest study ddLLTx (n = 138) was associated with a lower one-year-survival compared to conventional-LTx (n = 539) (65.1% vs 84.1%, P < 0.001). CONCLUSION Further investigations of optimal donor-to-recipient size matching parameters for ddLLTx could improve outcomes of this important surgical option

Lobar lung transplantation from deceased donors: A systematic review.

AimTo systematically review reports on deceased-donor-lobar lung transplantation (ddLLTx) and uniformly describe size matching using the donor-to-recipient predicted-total lung-capacity (pTLC) ratio.MethodsWe set out to systematically review reports on ddLLTx and uniformly describe size matching using the donor-to-recipient pTLC ratio and to summarize reported one-year survival data of ddLLTx and conventional-LTx. We searched in PubMed, CINAHL via EBSCO, Cochrane Database of Systematic Reviews via Wiley (CDSR), Database of Abstracts of Reviews of Effects via Wiley (DARE), Cochrane Central Register of Controlled Trials via Wiley (CENTRAL), Scopus (which includes EMBASE abstracts), and Web of Science for original reports on ddLLTx.ResultsNine observational cohort studies reporting on 301 ddLLTx met our inclusion criteria for systematic review of size matching, and eight for describing one-year-survival. The ddLLTx-group was often characterized by high acuity; however there was heterogeneity in transplant indications and pre-operative characteristics between studies. Data to calculate the pTLC ratio was available for 242 ddLLTx (80%). The mean pTLCratio before lobar resection was 1.25 ± 0.3 and the transplanted pTLCratio after lobar resection was 0.76 ± 0.2. One-year survival in the ddLLTx-group ranged from 50%-100%, compared to 72%-88% in the conventional-LTx group. In the largest study ddLLTx (n = 138) was associated with a lower one-year-survival compared to conventional-LTx (n = 539) (65.1% vs 84.1%, P &lt; 0.001).ConclusionFurther investigations of optimal donor-to-recipient size matching parameters for ddLLTx could improve outcomes of this important surgical option