Resonant tunneling diodes as sources for millimeter and submillimeter wavelengths

High-quality Resonant Tunneling Diodes have been fabricated and tested as sources for millimeter and submillimeter wavelengths. The devices have shown excellent I-V characteristics with peak-to-valley current ratios as high as 6:1 and current densities in the range of 50-150 kA/cm(exp 2) at 300 K. Used as local oscillators, the diodes are capable of state of the art output power delivered by AlGaAs-based tunneling devices. As harmonic multipliers, a frequency of 320 GHz has been achieved by quintupling the fundamental oscillation of a klystron source

Photonic stop bands in quasi-random nanoporous anodic alumina structures

The existence of photonic stop bands in the self-assembled arrangement of pores in porous anodic alumina structures is investigated by means of rigorous 2D finite- difference time-domain calculations. Self-assembled porous anodic alumina shows a random distribution of domains, each of them with a very definite triangular pattern, constituting a quasi-random structure. The observed stop bands are similar to those of photonic quasicrystals or random structures. As the pores of nanoporous anodic alumina can be infiltrated with noble metals, nonlinear or active media, it makes this material very attractive and cost-effective for applications including inhibition of spontaneous emission, random lasing, LEDs and biosensors

Mindfulness, worries, and parenting in parents of children with type 1 diabetes

Objective Parents of children with type 1 diabetes (T1D) often experience distress and worries, which may negatively impact their parenting behaviors. The current study investigates parental mindfulness (i.e., an enhanced attention to and awareness of current experiences or present reality) as a resilience mechanism. Using a daily diary approach, the predictive role of parental mindfulness for daily diabetes-related worries was examined, its impact upon protective parenting behaviors, and its buffering role in the relationship between daily worries and protective parenting behaviors. Methods Participants were 56 parents of 40 children with T1D (2–12 years). Trait mindfulness was assessed with the Mindful Attention Awareness Scale. Subsequently, parents completed a diary for 14 consecutive days, assessing parental worries about hypo- and hyperglycemia and general and diabetes-specific parental protective behavior. Results Multilevel analyses showed that parental diabetes-related worries fluctuated substantially across days and positively predicted daily protective behavior. Higher levels of parental mindfulness predicted less daily worries about hypoglycemia and lower engagement in general protective behavior and hypoglycemia avoidance behavior. In addition, the relationship between worries about hyperglycemia and general protective behavior was moderated by parental mindfulness. Conclusions The present findings highlight the importance of daily parental worries in explaining parental protective behaviors on a daily basis. Mindfulness emerged as a promising resilience factor in parents of children with T1D, resulting in less daily worries and protective parenting. These results have important clinical implications and point to the promising role of mindfulness interventions in this context

Families with pediatric type 1 diabetes : a comparison with the general population on child well-being, parental distress, and parenting behavior

Aims The aim of this study was to compare families with a child (2-12 years) with type 1 diabetes (T1D) to families which are not confronted with chronic illness, with regard to children's well-being, parental distress, and parenting behavior. In addition, differences were explored between families whose child has optimal vs suboptimal glycemic control. Methods Mothers, fathers, and children of 105 families with pediatric T1D completed questionnaires assessing child well-being, parental distress, and parenting. The control group consisted of 414 families without chronic illness. Results With regard to child well-being, children with T1D had more adjustment difficulties (as reported by mothers) and lower quality of life (QoL) (as reported by mothers and fathers), whereas children themselves (8-12 years) reported higher QoL compared to controls. In terms of parental distress, mothers, but not fathers, of children with T1D reported more stress, anxiety symptoms, and depressive symptoms than controls. With regard to parenting behavior, parent reports revealed less protectiveness in fathers and less autonomy support and responsiveness in both parents as compared to controls. No differences were found in parent-reported psychological control between parents of children with and without T1D, but children with T1D perceived lowered parental psychological control. Lastly, secondary analyses indicated that especially families with suboptimal child glycemic control showed more maternal distress and worse child well-being (according to parents). Conclusions Families confronted with pediatric T1D differ from families without chronic illness: childhood T1D impacts parental perceptions of child well-being and differentially affects mothers' and fathers' distress levels and behaviors