No abstract

Nature has adapted different methods for surviving dry, arid, xeric conditions. It is the focus of this comparative review to pull together the relevant information gleaned from the literature that could be utilized to design moisture harvesting devices informed by biomimetics. Most water harvesting devices in current use are not informed by nature and those that do are usually based on a biomimetic principle that has been based on one species only. This review draws on the published literature to establish a list of species (animals (vertebrates/invertebrates) and plants) whose habitat is in mainly dry or arid regions and that are known to harvest airborne moisture. Key findings have been outlined and review comments and discussion set out. Following this, surface feature convergences have been identified, namely hexagonal microstructures, groove-like and cone-like geometries. This has been coupled with direction of water flow that is driven by surface energy. As far as the authors are aware, this convergent evolution has not been brought together in this manner before. In the future this information could be translated into an engineered device for collecting water from airborne sources.

Attention-deficit hyperactivity disorder (ADHD) is frequently found in childhood and persists in about 50% of cases into adulthood. Several studies demonstrate a relationship between ADHD, circadian rhythmicity and sleeping disturbances in unmedicated ADHD patients. Since ADHD is a very complex disease with a high genetic load involving multiple genes of moderate effect, we hypothesized a link between adult ADHD and genes involved in the circadian timekeeping system. A 3'-UTR polymorphism of the circadian locomotor output cycles protein kaput (CLOCK) gene, rs1801260, has been linked to disturbed sleep patterns, although both the C-allele and more controversially the T-allele have been proposed as risk factors for different measures of evening preference. This study compared self-rating and interview based measures of ADHD psychopathology of 143 subjects with and without ADHD with their rs1801260 genotype to test the hypothesis that ADHD is linked to one of the alleles of the CLOCK polymorphism. The T > C single nucleotide polymorphism rs1801260 was genotyped in DNA isolated from blood samples. The associations between genotype and ADHD-scores were compared using non-parametric ANCOVA with post hoc pairwise comparisons. There was a strong, significant association (P < 0.001) between each of the adult ADHD assessments and the rs1801260 polymorphism with at least one T-mutation being the risk allele. This is the first study suggesting that a polymorphism of a gene within the circadian "clock" mechanism is a direct or linked contributing factor in adult ADHD.

No abstract

Four species of cacti were chosen for this study: Copiapoa cinerea var. haseltoniana, Ferocactus wislizenii, Mammillaria columbiana subsp. yucatanensis and Parodia mammulosa. It has been reported that dew condenses on the spines of C. cinerea and that it does not on the spines of F. wislizenii, and our preliminary observations of M. columbiana and P. mammulosa revealed a potential for collecting dew water. This study found all four cacti to harvest dew on their stems and spines (albeit rarely on the spines of F. wislizenii). Dew harvesting experiments were carried out in the UK, recording an increase in cacti mass on dewy nights. By applying a ranking relative to a polymethyl methacrylate (Plexiglas) reference plate located nearby, it was found that C. cinerea collected the most airborne moisture followed by M. columbiana, P. mammulosa and F. wislizenii respectively, with mean efficiency ratio with respect to the Plexiglas reference of 3.48 ± 0.5, 2.44 ± 0.06, 1.81 ± 0.14 and 1.27 ± 0.49 on observed dewy nights. A maximum yield of normalized performance of 0.72 ± 0.006 l/m(-2) on one dewy night was recorded for C. cinerea. Removing the spines from M. columbiana was found to significantly decrease its dew harvesting efficiency. The spines of three of the species were found to be hydrophilic in nature, while F. wislizenii was hydrophobic; the stems of all four species were hydrophilic. The results of this study could be translated into designing a biomimetic water collecting device that utilizes cactus spines and their microstructures.

No abstract

Adult attention deficit hyperactivity disorder (ADHD) is a widely under-reported but nevertheless common condition with a clear heritable component. Several genes have been proposed to play a role in the childhood onset of this neurodevelopmental disorder; however, association studies of persistence of ADHD into adulthood have rarely been performed. Neurotrophic factors (NTFs) are known to be involved in several aspects of neuronal development and neural plasticity in adults. They have also been linked, particularly through brain-derived neurotrophic factor (BDNF) interaction with dopamine transport, to the pathophysiology of ADHD. This study compares the genotypes of six different single nucleotide polymorphisms of genes within the neurotrophin system and their possible association with adult ADHD score in 143 high-risk male subjects referred to a forensic psychiatric unit. The genes included NTF3, NTRK2 (TrkB), NTRK3 (TrkC), BDNF, and p75(NTR). While none of the SNPs showed significant association with ADHD symptoms, one polymorphism within the exon of NTF3 (rs6332) showed a trend toward an association between the A-allele and increased scores using both the retrospective childhood analysis Wender-Utah Rating Scale (WURS-k) (P = 0.05) and the adult ADHD assessment Wender-Reimherr interview (P = 0.03). This SNP is a silent mutation which might be in linkage disequilibrium with a functional risk variant for ADHD. As the association was only suggestive, however, this finding needs replication in a larger study with higher power.

Objective: To study the safety and efficacy of hydroxyethylrutosides (HR) in patients with chronic venous insufficiency (CVI) (Widmer grade II) and examine any correlation with objective measurements (plethysmography and Tc Po2). Design: Double-blind, randomized, placebo-controlled, multicentre trial. Setting: One outpatient university angiology clinic, one outpatient angiology clinic in a military hospital and one private angiological consultation, all in the Paris area. Patients: One hundred and nine patients with grade II Widmer CVI, confirmed by echo-Doppler and plethysmography. Elastic stockings were excluded. After five exclusions, 53 received HR and 51 placebo. Interventions: Patients randomized to one sachet of 1 g HR twice daily (or placebo) for 2 months, after a 1 month placebo run-in period. Examinations on entry to the trial (T–1), after 1 month run-in (T–0) and after 1 (T+1) and 2 months (T+2) treatment. Main outcome measures: These were measured at each of the four visits. Primary outcome: minimal ankle and maximal calf circumferences. Secondary outcomes: five individual leg symptoms and total symptom score, pitting oedema. Plethysmography (six calculated variables) and Tc Po2. Results: The reduction of both ankle and calf circumferences was significantly greater in the HR group ( p<0.0001), as was pitting oedema ( p<0.001), the five individual symptoms and the total symptom score ( p<0.001). Of the plethysmographic findings, there was a significant reduction in maximum venous outflow ( p<0.001 at T+1 and p<0.05 at T+2). Overall there was no significant change in Tc Po2. Conclusions: HR is an effective and well-tolerated treatment for leg oedema and symptoms of patients with CVI.