Selectivity and specificity: pros and cons in sensing

Sensing using specific and selective receptors provides two very different but complementary strategies. This Sensor Issues article will discuss the merits and challenges of specific sensors, and selective sensors based on synthetic arrays. We will examine where each has been successfully applied to a sensing challenge, and then look at how a combined approach could take elements of both to provide new sensor platforms

Factors predicting physical activity among children with special needs.

IntroductionObesity is especially prevalent among children with special needs. Both lack of physical activity and unhealthful eating are major contributing factors. The objective of our study was to investigate barriers to physical activity among these children.MethodsWe surveyed parents of the 171 children attending Vista Del Mar School in Los Angeles, a nonprofit school serving a socioeconomically diverse group of children with special needs from kindergarten through 12th grade. Parents were asked about their child's and their own physical activity habits, barriers to their child's exercise, and demographics. The response rate was 67%. Multivariate logistic regression was used to examine predictors of children being physically active at least 3 hours per week.ResultsParents reported that 45% of the children were diagnosed with attention deficit hyperactivity disorder, 38% with autism, and 34% with learning disabilities; 47% of children and 56% of parents were physically active less than 3 hours per week. The top barriers to physical activity were reported as child's lack of interest (43%), lack of developmentally appropriate programs (33%), too many behavioral problems (32%), and parents' lack of time (29%). However, child's lack of interest was the only parent-reported barrier independently associated with children's physical activity. Meanwhile, children whose parents were physically active at least 3 hours per week were 4.2 times as likely to be physically active as children whose parents were less physically active (P = .01).ConclusionIn this group of students with special needs, children's physical activity was strongly associated with parental physical activity; parent-reported barriers may have had less direct effect. Further studies should examine the importance of parental physical activity among children with special needs

A survey on the possibility of utilizing γH2AX as a biodosimeter in radiation workers

Introduction DNA damage is among the main consequences of radiation. Of many different classes of DNA damage, double-strand breaks are the most deleterious. Development of a sensitive biodosimetry method, which utilizes a detection material with a similar construction to the body, seems essential for monitoring radiation workers. In this study, histone H2AX protein was examined as a potential biodosimeter in radiation workers. Moreover, the presence of this protein after in vitro irradiation of blood samples was assessed simultaneously. Materials and Methods Blood samples from 46 radiation workers were analyzed in Golestan province, Iran. Meanwhile, two groups of blood samples (five blood samples in each group) were irradiated in vitro by doses of 1 to 0.2 Gy and 0.09 to 0.01 Gy from a 60Co source, respectively. γH2AX level in lymphocytes was measured, using Western blot technique. ANOVA and Tukey's tests were performed, using SPSS version 16. The significance level was considered to be 0.05. Results The results of Western blotting for the identification of γH2AX protein in radiation workers were negative. However, γH2AX level in lymphocytes of two in vitro irradiated groups showed a significant correlation with the radiation dose (P<0.0001). Conclusion The results showed that γH2AX was a good indicator for acute or local exposure to ionizing radiation, while in chronically exposed individuals, including radiation workers, this protein was useless at least in autoradiography detection method. Regarding the presence of γH2AX protein in blood samples, which were irradiated in vitro at low doses, it can be concluded that this protein has powerful repair mechanisms

In-depth description of Electrohydrodynamic conduction pumping of dielectric liquids: physical model and regime analysis

In this work, we discuss the fundamental aspects of Electrohydrodynamic (EHD) conduction pumping of dielectric liquids. We build a mathematical model of conduction pumping that can be applied to all sizes, down to microsized pumps. In order to do this, we discuss the relevance of the Electrical Double Layer (EDL) that appears naturally on nonmetallic substrates. In the process, we identify a new dimensionless parameter related to the value of the zeta potential of the substrate-liquid pair, which quantifies the influence of these EDLs on the performance of the pump. This parameter also describes the transition from EHD conduction pumping to electro-osmosis. We also discuss in detail the two limiting working regimes in EHD conduction pumping: ohmic and saturation. We introduce a new dimensionless parameter, accounting for the electric field enhanced dissociation that, along with the conduction number, allows us to identify in which regime the pump operates.Ministerio de Ciencia, Innovación y Universidades PGC2018-099217-B-I0

Atom Transfer and Single-Adatom Contacts

The point contact of a tunnel tip approaching towards Ag(111) and Cu(111) surfaces is investigated with a low temperature scanning tunneling microscope. A sharp jump-to-contact, random in nature, is observed in the conductance. After point contact, the tip-apex atom is transferred to the surface, indicating that a one-atom contact is formed during the approach. In sharp contrast, the conductance over single silver and copper adatoms exhibits a smooth and reproducible transition from tunneling to contact regime. Numerical simulations show that this is a consequence of the additional dipolar bonding between the homoepitaxial adatom and the surface atoms.Comment: 4 pages, 4 figure

Robust optimization over time by learning problem space characteristics

Robust optimization over time is a new way to tackle dynamic optimization problems where the goal is to find solutions that remain acceptable over an extended period of time. The state-of-the-art methods in this domain try to identify robust solutions based on their future predicted fitness values. However, predicting future fitness values is difficult and error prone. In this paper, we propose a new framework based on a multi-population method in which sub-populations are responsible for tracking peaks and also gathering characteristic information about them. When the quality of the current robust solution falls below the acceptance threshold, the algorithm chooses the next robust solution based on the collected information. We propose four different strategies to select the next solution. The experimental results on benchmark problems show that our newly proposed methods perform significantly better than existing algorithms

Cd3As2 is Centrosymmetric

This is a revised version of a manuscript that was originally posted here in February of 2014. It has been accepted at the journal Inorganic Chemistry after reviews that included those of two crystallographers who made sure all the t's were crossed and the i's were dotted. The old work (from 1968) that said that Cd3As2 was noncentrosymmetric was mistaken, with the authors of that study making a type of error that in the 1980s became infamous in crystallography. As a result of the increased scrutiny of the issue of centrosymmetricity of the 1980's, there are now much better analysis tools to resolve the issue fully, and its important to understand that not just our crystals are centrosymmetric, even the old guy's crystals were centrosymmetric (and by implication everyone's are). There is no shame in having made that error back in the day and those authors would not find the current centrosymmetric result controversial; their paper is excellent in all other aspects. This manuscript describes how the structure is determined, explains the structure schematically, calculates the electronic structure based on the correct centrosymmetric crystal structure, and gives the structural details that should be used for future analysis and modeling.Comment: Accepted by ACS Inorganic Chemistr