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light sense [keywords]
- Apparatus for investigating the reactions of soft-bodied invertebrates to controlled humidity gradients. [JOURNAL ARTICLE]
- J Neurosci Methods 2014 Aug 28.
While many studies have assayed behavioral responses of animals to chemical, temperature and light gradients, fewer studies have assayed how animals respond to humidity gradients. Our novel humidity chamber has allowed us to study the neuromolecular basis of humidity sensation in the nematode Caenorhabditis elegans (Russell et al., 2014).We describe an easy-to-construct, low-cost humidity chamber to assay the behavior of small animals, including soft-bodied invertebrates, in controlled humidity gradients.We show that our humidity-chamber design is amenable to soft-bodied invertebrates and can produce reliable gradients ranging 0.3-8% RH/cm across a 9-cm long x 7.5-cm wide gel-covered arena.Previous humidity chambers relied on circulating dry and moist air to produce a steep humidity gradient in a small arena (e.g. Sayeed and Benzer, 1996). To remove the confound of moving air that may elicit mechanical responses independent of humidity responses, our chamber controlled the humidity gradient using reservoirs of hygroscopic materials. Additionally, to better observe the behavioral mechanisms for humidity responses, our chamber provided a larger arena. Although similar chambers have been described previously, these approaches were not suitable for soft-bodied invertebrates or for easy imaging of behavior because they required that animals move across wire or fabric mesh.The general applicability of our humidity chamber overcomes limitations of previous designs and opens the door to observe the behavioral responses of soft-bodied invertebrates, including genetically powerful C. elegans and Drosophila larvae.
- Theoretical voltammetric response of electrodes coated by solid polymer electrolyte membranes. [JOURNAL ARTICLE]
- Anal Chim Acta 2014 Sep 24.:15-26.
A model for the differential capacitance of metal electrodes coated by solid polymer electrolyte membranes, with acid/base groups attached to the membrane backbone, and in contact with an electrolyte solution is developed. With proper model parameters, the model is able to predict a limit response, given by Mott-Schottky or Gouy-Chapman-Stern theories depending on the dissociation degree and the density of ionizable acid/base groups. The model is also valid for other ionic membranes with proton donor/acceptor molecules as membrane counterions. Results are discussed in light of the electron transfer rate at membrane-coated electrodes for electrochemical reactions that strongly depend on the double layer structure. In this sense, the model provides a tool towards the understanding of the electro-catalytic activity on modified electrodes. It is shown that local maxima and minima in the differential capacitance as a function of the electrode potential may occur as consequence of the dissociation of acid/base molecular species, in absence of specific adsorption of immobile polymer anions on the electrode surface. Although the model extends the conceptual framework for the interpretation of cyclic voltammograms for these systems and the general theory about electrified interfaces, structural features of real systems are more complex and so, presented results only are qualitatively compared with experiments.
- Fabry disease: a survey of visual and ocular symptoms. [Journal Article]
- Clin Ophthalmol 2014.:1555-60.
To evaluate a visual symptoms survey on patients with a known diagnosis of Fabry disease, and to compare the scores to those from a group of healthy subjects.An ocular symptom survey instrument was used to evaluate the symptoms of general ocular problems like itching, tearing, dryness, burning sensation, sensation of foreign body, difficulty in scotopic and photopic vision, and asthenopic symptoms. The survey instrument was administered to 95 participants (75 patients with Fabry disease and 20 healthy controls; median age: 32.5 years [standard deviation: 19.1 years] and 42.6 years [standard deviation: 14.7 years], respectively). A Mann-Whitney test was performed to evaluate the difference between the Fabry group and the healthy controls for each symptom survey severity score. A P-value <0.05 was considered significant.Of the survey instrument items, it was found that compared to the control group, the mean severity score of the Fabry disease group was significant for "dryness" of the eyes (P=0.02), "blurry/dim vision" (P=0.02), "hard to see in dark places" (P=0.01), and "halos around light" (P=0.01). The Fabry group also had a mean severity score for "soreness/tiredness" that was significantly higher than that of the control group (P=0.009).The patients with Fabry disease may be suffering from ocular and visual symptoms related to manifestations of the disease. Further quantitative testing is needed to investigate the ocular and visual symptoms.
- Cerebrospinal fluid neurofilament tracks fMRI correlates of attention at the first attack of multiple sclerosis. [JOURNAL ARTICLE]
- Mult Scler 2014 Aug 28.
Identifying markers of cognitive dysfunction in multiple sclerosis (MS) is extremely challenging since it means supplying potential biomarkers for neuroprotective therapeutic strategies.The aim of this study is to investigate the relationship between fMRI correlates of attention performance and cerebrospinal fluid (CSF) neurofilament light chain (NFL) levels in patients with clinically isolated syndrome (CIS) suggestive of MS.Twenty-one untreated, cognitively preserved CIS patients underwent BOLD-fMRI while performing the Variable Attentional Control (VAC) task, a cognitive paradigm requiring increasing levels of attentional control processing. CSF NFL was assessed by ELISA technique. SPM8 random-effects models were used for statistical analyses of fMRI data (p<0.05 corrected).Repeated-measures ANOVA on imaging data showed an interaction between attentional control load and NFL levels in the right putamen. At the high level of attentional control demand CIS patients with "low NFL levels" showed greater activity in the putamen compared with subjects with "high NFL levels" (p=0.001). These results are independent of cognitive impairment index.Our findings suggest a relationship between CSF NFL levels and load-dependent failure of putaminal recruitment pattern during sustained attention in CIS and suggest a role of CSF NFL as a marker of subclinical abnormality of cognitive pathway recruitment in CIS.
- `Becoming human again': Exploring connections between nature and recovery from stress and post-traumatic distress. [JOURNAL ARTICLE]
- Work 2014 Aug 28.
Many military veterans are seeking ways beyond conventional treatments to manage their stress injuries. An increasing number is turning to nature, including hiking and fishing, farming and gardening, and building relationships with dogs or horses. Many continue to benefit from medication and therapy, but find that nature provides an additional measure of support, relief and healing in their lives.This paper examines reciprocal interactions between humans and nature during post-conflict recovery, with a focus on the experiences of four North American veterans who regard their personal recovery from stressful and traumatic military experiences as intimately tied to their nature experiences.Experience-centered narrative inquiry often sheds light on details and experiences concealed or overlooked by other research paradigms. In-depth interviews about post-military experiences with recovery were conducted with four veterans who suffer from stress and/or post-traumatic distress; these experiences are further illuminated by supporting interviews, and theories and praxis in ecopsychology, cognitive science, neuroscience, biophilia, and ecological intelligence.Through exploring themes of sensory experience, safety, sense of purpose, and renewed relationships, this research gives space to former soldiers' stories of experience and to their individual realizations that their embodied interconnections with nature provide alternative experiences to their military training and combat exposure.The veterans' experiences with nature and recovery are pointing towards an avenue of recovery that is little acknowledged in the mainstream literature and praxis, but deserving of attention.
- Short-Term Effects of Bright Light Therapy in Adults with Chronic Nonspecific Back Pain: A Randomized Controlled Trial. [JOURNAL ARTICLE]
- Pain Med 2014 Aug 26.
The present trial evaluated incorporation of bright light therapy in the treatment of chronic nonspecific back pain (CNBP).A prospective, randomized, controlled, multicenter, open design with three parallel trial arms was used.Subjects received a novel therapeutic, an expected therapeutic ineffective low dose, or no light exposure at three different medical centers.A total of 125 CNBP patients reporting pain intensity of ≥3 points on item 5 of the Brief Pain Inventory (BPI) were included.Over 3 weeks, 36 active treatment, 36 placebo controls, and 33 controls received 3 or no supplementary light exposures of 5.000 lx or 230 lx, respectively.Changes in self-reported scores of pain intensity (BPI sub-score 1) and depression (Hospital Anxiety and Depression Questionnaire) were the primary outcome measures. Secondary outcome measures were changes in self-reported overall pain sensation (BPI total score), grade of everyday life impairment (BPI sub-score 2), mood (visual analog scale), and well-being (World Health Organization-Five Well-Being Index).Changes in pain intensity were higher (1.0 [0.8-1.6]) in the bright light group compared with controls (0.3 [-0.1-0.8]; effect size D = 0.46). Changes in the depression score were also higher in the intervention group (1.5 [0.0-2.5]) compared with controls (0.0 [0.0-2.0]; effect size D = 0.86). No differences were seen in change scores between intervention vs sham group.The present randomized controlled trial shows that light therapy even in low dose could improve depressive symptoms and reduce pain intensity in CNBP patients. Further research is needed for optimizing parameters of frequency, dose, and duration of therapeutic light exposure.
- Genetic control and estimation of genetic parameters for seed-coat darkening of carioca beans. [Journal Article]
- Genet Mol Res 2014; 13(3):6486-96.
The maintenance of the light color of the grains of carioca beans is a requirement for the development of new cultivars of common beans because it enables the storage of grains for long periods so that they may be traded at a proper opportunity. Crosses of cultivar BRSMG Madrepérola, which presents slow grain darkening, were made to 10 elite lines presenting normal darkening to obtain information about the genetic control of the trait and estimates of phenotypic and genotypic parameters. Progenies at the tegument generations F3 and F4 and their parents were evaluated at the locations of Santo Antônio de Goiás and Ponta Grossa at 71, 106, and 155 days of storage for seed-coat darkening using a rank of scores ranging from 1 (very light colored grains) to 5 (very dark colored grains). Genotypic and phenotypic variances and broad-sense heritabilities were estimated for each population. The segregation ratios were subjected to the chi-square test to establish the genetic control. Some populations did not present consistent patterns of genetic control, while others presented monogenic or double-recessive digenic segregation, indicating that the trait is controlled by few genes. Six segregant populations were identified with both low means for darkening and high expected gain under selection. Despite the strong environmental influence on the expression of the traits and the occurrence of the genotype by environment interaction, the estimates of genotypic and phenotypic parameters indicate the possibility of successful selection to develop lines with slow seed-coat darkening.
- Do textured insoles effect postural control and spatiotemporal parameters of gait and plantar sensation in people with multiple sclerosis? [JOURNAL ARTICLE]
- PM R 2014 Aug 18.
Balance and gait deficits are common in people with multiple sclerosis (MS). Physical interventions directed at improving balance and walking abilities have implemented using various approaches. Nonetheless, no mode of training has been universally agreed upon.To determine if textured insoles have immediate effects on postural control and spatiotemporal parameters of gait and plantar sensation in people with people with MS and to explore effects 4 weeks after insole wear as to whether any immediate effects are maintained over time.Within-subject experimental study with a 4-week intervention phase.Multiple Sclerosis Center, Center of Advanced Technologies in Rehabilitation, Sheba Medical Center, Tel-Hashomer, Israel.Twenty-five relapsing-remitting patients diagnosed with MS, 16 women and 9 men, aged 49.6 (S.D= 6.5) years.Textured insoles customized according to foot size and adapted to the participant's casual shoes.Spatiotemporal parameters of gait and center of pressure (CoP) excursions during static postural control were studied using the Zebris FDM-T Treadmill (Zebris® Medical GmbH, Germany). Light-touch and pressure-sensation thresholds were determined using the Semmes-Weinstein monofilaments test RESULTS: Textured insoles did not alter static postural control parameters when examined with eyes open. Examination during the eyes closed task demonstrated an immediate reduction in the CoP path length (298.4 (S.E.=49.7) vs. 369.9 (S.E.=56.3); mm; P=.04) and sway rate (12.0 (S.E.=1.4) vs. 15.1 (S.E.=1.6); mm/s; P=.03) following insertion of the textured insoles compared to casual shoes. These findings were maintained at termination of the insole 4-week intervention period. In terms of spatiotemporal parameters of gait, differences were not observed between casual shoes and shoes with textured insoles at baseline. Likewise, no differences were observed between initial and concluding gait trials. Significant differences in plantar sensitivity measures were not observed following the insole 4-week intervention phase.Although there were improvements in some aspects of balance, the efficacy of textured insoles in the MS population remains unclear.
- Effect of arsenic on reflectance spectra and chlorophyll fluorescence of aquatic plants. [JOURNAL ARTICLE]
- Chemosphere 2014 Aug 21.:697-703.
Arsenic pollution of groundwater is a serious problem in many regions of Latin America that causes severe risks to human health. As a consequence, non-destructive monitoring methodologies, sensitive to arsenic presence in the environment and able to perform a rapid screening of large polluted areas, are highly sought-after. Both chlorophyll - a fluorescence and reflectance of aquatic plants may be potential indicators to sense toxicity in water media. In this work, the effects of arsenic on the optical and photophysical properties of leaves of different aquatic plants (Vallisneria gigantea, Azolla filiculoides and Lemna minor) were evaluated. Reflectance spectra were recorded for the plant leaves from 300 to 2400nm. The spectral distribution of the fluorescence was also studied and corrected for light re-absorption processes. Photosynthetic parameters (Fv/Fm and ΦPSII) were additionally calculated from the variable chlorophyll fluorescence recorded with a pulse amplitude modulated fluorometer. Fluorescence and reflectance properties for V. gigantea and A. filiculoides were sensitive to arsenic presence in contrast to the behaviour of L. minor. Observed changes in fluorescence spectra could be interpreted in terms of preferential damage in photosystem II. The quantum efficiency of photosystem II for the first two species was also affected, decreasing upon arsenic treatment. As a result of this research, V. gigantea and A. filiculoides were proposed as bioindicators of arsenic occurrence in aquatic media.
- When Proteins Start to Make Sense: Fine-tuning Aminoglycosides for PTC Suppression Therapy. [JOURNAL ARTICLE]
- Medchemcomm 2014 Aug 1; 5(8):1092-1105.
Aminoglycosides (AGs) are highly potent antibacterial agents, which are known to exert their deleterious effects on bacterial cells by interfering with the translation process, leading to aberrant protein synthesis that usually results in cell death. Nearly 45 years ago, AGs were shown to induce read-through activity in prokaryotic systems by selectively encoding tRNA molecules at premature termination codon (PTC) positions; resulting in the generation of full length functional proteins. However, only in the last 20 years this ability has been demonstrated in eukaryotic systems, highlighting their potential as therapeutic agents to treat PTC induced genetic disorders. Despite the great potential, AGs use in these manners is quite restricted due to relatively high toxicity values observed upon their administration. Over the last few years several synthetic derivatives were developed to overcome some of the enhanced toxicity issues, while in parallel showed significantly improved PTC suppression activity in various in-vitro, ex-vivo and in-vivo models of a variety of different diseases models underling by PTC mutations. Although these derivatives hold great promise to serve as therapeutic candidates they also demonstrate the necessity to further understand the molecular mechanisms of which AGs confer their biological activity in eukaryotic cells for further rational drug design. Recent achievements in structural research shed light on AGs mechanism of action and opened a new avenue in the development of new and improved therapeutic derivatives. The following manuscript highlights these accomplishments and summarizes their contributions to the state of art rational drug design.