Functionalized and Nanostructured Fibers for Photocatalysis and Energy Conversion

Fiber-type / flexible materials present a unique opportunity for the incorporation of photocatalytic / energy generating technology, as they typically have a broad surface area exposed to light (clothing, curtains, carpet). In this work, several methods of harvesting incident light striking a flexible substrate to perform useful work are examined. In the first section a gold and silver nanoparticle augmented TiO2 thin film textile coating is evaluated for its self-cleaning / UV-protective / anti-microbial properties, and stability of the film / substrate over time is examined. In the second section a dye sensitized / hybrid type solar cell architecture based on flexible carbon nanotube yarn is evaluated for its ability to convert incident light into electrical energy. In the final section an entirely polymer / hybrid based solar cell architecture also based on carbon nanotube yarn is evaluated and the relative strengths of flexible polymer-type cells are discussed

Functional materials, device architecture, and flexibility of perovskite solar cell

Perovskite solar cells (PSCs) are an emerging photovoltaic technology that promises to offer facile and efficient solar power generation to meet future energy needs. PSCs have received considerable attention in recent years, have attained power conversion efficiencies (PCEs) over 22%, and are a promising candidate to potentially replace the current photovoltaic technology. The emergence of PSCs has revolutionized photovoltaic research and development because of their high efficiencies, inherent flexibility, the diversity of materials/synthetic methods that can be employed to manufacture them, and the various possible device architectures. Further optimization of material compositions and device architectures will help further improve efficiency and device stability. Moreover, the search for new functional materials will allow for mitigation of the existing limitations of PSCs. This review covers the recently developed advanced techniques and research trends related to this emerging photovoltaic technology, with a focus on the diversity of functional materials used for the various layers of PSC devices, novel PSC architectures, methods that increase overall cell efficiency, and substrates that allow for enhanced device flexibility

Zeros and the functional equation of the quadrilateral zeta function

In this paper, we show that all real zeros of the bilateral Hurwitz zeta function $Z(s,a):=\zeta (s,a) + \zeta (s,1-a)$ with $1/4 \le a \le 1/2$ are on only the non-positive even integers exactly same as in the case of $(2^s-1) \zeta (s)$. We also prove that all real zeros of the bilateral periodic zeta function $P(s,a):={\rm{Li}}_s (e^{2\pi ia}) + {\rm{Li}}_s (e^{2\pi i(1-a)})$ with $1/4 \le a \le 1/2$ are on only the negative even integers just like $\zeta (s)$. Moreover, we show that all real zeros of the quadrilateral zeta function $Q(s,a):=Z(s,a) + P(s,a)$ with $1/4 \le a \le 1/2$ are on only the negative even integers. On the other hand, we prove that $Z(s,a)$, $P(s,a)$ and $Q(s,a)$ have at least one real zero in $(0,1)$ when $0<a<1/2$ is sufficiently small. The complex zeros of these zeta functions are also discussed when $1/4 \le a \le 1/2$ is rational or transcendental. As a corollary, we show that $Q(s,a)$ with rational $1/4 < a < 1/3$ or $1/3 < a < 1/2$ does not satisfy the analogue of the Riemann hypothesis even though $Q(s,a)$ satisfies the functional equation that appeared in Hamburger's or Hecke's theorem and all real zeros of $Q(s,a)$ are located at only the negative even integers again as in the case of $\zeta (s)$.Comment: 12 pages. We changed the title. Some typos are correcte

Gene signature of the post-Chernobyl papillary thyroid cancer

Purpose: Following the nuclear accidents in Chernobyl and later in Fukushima, the nuclear community has been faced with important issues concerning how to search for and diagnose biological consequences of low-dose internal radiation contamination. Although after the Chernobyl accident an increase in childhood papillary thyroid cancer (PTC) was observed, it is still not clear whether the molecular biology of PTCs associated with low-dose radiation exposure differs from that of sporadic PTC. Methods: We investigated tissue samples from 65 children/young adults with PTC using DNA microarray (Affymetrix, Human Genome U133 2.0 Plus) with the aim of identifying molecular differences between radiation-induced (exposed to Chernobyl radiation, ECR) and sporadic PTC. All participants were resident in the same region so that confounding factors related to genetics or environment were minimized. Results: There were small but significant differences in the gene expression profiles between ECR and non-ECR PTC (global test, p &lt; 0.01), with 300 differently expressed probe sets (p &lt; 0.001) corresponding to 239 genes. Multifactorial analysis of variance showed that besides radiation exposure history, the BRAF mutation exhibited independent effects on the PTC expression profile; the histological subset and patient age at diagnosis had negligible effects. Ten genes (PPME1, HDAC11, SOCS7, CIC, THRA, ERBB2, PPP1R9A, HDGF, RAD51AP1, and CDK1) from the 19 investigated with quantitative RT-PCR were confirmed as being associated with radiation exposure in an independent, validation set of samples. Conclusion: Significant, but subtle, differences in gene expression in the post-Chernobyl PTC are associated with previous low-dose radiation exposure

Position weight matrix model as a tool for the study of regulatory elements distribution across the DNA sequence

Ab initio methods of DNA regulatory sequence region prediction known as transcription factor binding sites (TFBS) are a very big challenge to modern bioinformatics. Although the currently available methods are not perfect they are fairly reliable and can be used to search for new potential protein-DNA interaction sites. The biggest problem of ab initio approaches is the very high false positive rate of predicted sites which results mainly from the fact that TFBS are very short and highly degenerate. Because of that they can occur by chance every few hundred bases making the task of computational prediction extremely difficult if one aims to reduce the high false positive rate keeping highest possible sensitivity to predict biologically meaningful sequence regions. In this work we present a new application that can be used to predict TFBS regions in very large datasets based on position weight matrix models (PWM’s) using one of the most popular prediction methods. The presented application was used to predict the concentration of TFBS in a set of nearly 2.2 thousand unique sequences of human gene promoter regions. The study revealed that the concentration of TFBS further than 1kbp from the transcription initiation site is constant but it decreases rapidly while getting closer to the transcription initiation site. The decreasing TFBS concentration in the vicinity of genes might result from evolutionary selection which keeps only sites responsible for interactions with proteins being part of a specific regulatory mechanism leading to cells survival