Field spectroradiometry for discrimination of wetland components: a case study of a tropical inland wetland in India

Remote sensing has emerged as an effective tool for mapping, monitoring and assessment of wetland ecosystems. Spectral resolution of hyperspectral imagery allows collection of extensive information on dynamics of wetland components. Development of comprehensive spectral libraries using field spectroradiometry is imperative to tap the potential of hyperspectral imagery. In this study, an attempt has been made (i) to test the efficacy of field spectroradiometry data and processing techniques for identification and discrimination of wetland components, and (ii) to develop an approach for creating an extensive library for wetland components. Canopy level spectra of 13 macrophyte species representing different life-forms and water column reflectance spectra were collected seasonally at 16 sites in Bhindawas wetland of India for the years 2014 and 2015. Field spectra were processed using spectroscopic techniques including smoothing, derivative analysis and continuum removal. Results show derivative transforms to be efficient in identification and discrimination of wetland components. Magnitude and position of red-edge peak successfully discriminated different macrophytes with maximum and minimum value for Nymphoides indica and Hydrilla verticillata respectively. Continuum removal further strengthens the attributes of spectral data for species discrimination. Algorithms developed based on derivative transforms of water column spectra allow for continuous monitoring of bio-optical parameters and trophic status of the wetland. As a result of this research, sample-sets of field spectra providing a sound base for mapping and monitoring of wetland components were compiled, leading to the development of the first spectral library for an inland freshwater wetland in the Indian subcontinent. This research output in conjunction with advanced analytical tools and algorithms shall be utilized for wetland assessment in future studies.     

Real-Time DC-dynamic Biasing Method for Switching Time Improvement in Severely Underdamped Fringing-field Electrostatic MEMS Actuators

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input bias voltage. However, the tradeoff for the improved switching performance is a relatively long settling time to reach each gap height in response to various applied voltages. Transient applied bias waveforms are employed to facilitate reduced switching times for electrostatic fringing-field MEMS actuators with high mechanical quality factors. Removing the underlying substrate of the fringing-field actuator creates the low mechanical damping environment necessary to effectively test the concept. The removal of the underlying substrate also a has substantial improvement on the reliability performance of the device in regards to failure due to stiction. Although DC-dynamic biasing is useful in improving settling time, the required slew rates for typical MEMS devices may place aggressive requirements on the charge pumps for fully-integrated on-chip designs. Additionally, there may be challenges integrating the substrate removal step into the back-end-of-line commercial CMOS processing steps. Experimental validation of fabricated actuators demonstrates an improvement of 50x in switching time when compared to conventional step biasing results. Compared to theoretical calculations, the experimental results are in good agreement.     

Danger signalling during cancer cell death: origins,plasticity and regulation

Accumulating data indicates that following anti-cancer treatments, cancer cell death can be perceived as immunogenic or tolerogenic by the immune system. The former is made possible due to the ability of certain anti-cancer modalities to induce immunogenic cell death (ICD) that is associated with the emission of damage-associated molecular patterns (DAMPs), which assist in unlocking a sequence of events leading to the development of anti-tumour immunity. In response to ICD inducers, activation of endoplasmic reticulum (ER) stress has been identified to be indispensable to confer the immunogenic character of cancer cell death, due to its ability to coordinate the danger signalling pathways responsible for the trafficking of vital DAMPs and subsequent anti-cancer immune responses. However, in recent times, certain processes apart from ER stress have emerged (e.g., autophagy and possibly viral response-like signature), which have the ability to influence danger signalling. In this review, we discuss the molecular nature, emerging plasticity in the danger signalling mechanisms and immunological impact of known DAMPs in the context of immunogenic cancer cell death. We also discuss key effector mechanisms modulating the interface between dying cancer cells and the immune cells, which we believe are crucial for the therapeutic relevance of ICD in the context of human cancers, and also discuss the influence of experimental conditions and animal models on these.     

Dietary supplementation with resveratrol and/or docosahexaenoic acid alters hippocampal gene expression in adult C57Bl/6 mice

The hippocampus is an important brain structure for multiple cognitive functions, including memory formation. It is particularly sensitive to insults, such as stress, ischemia, and aging; all of these can affect hippocampal and therefore cognitive function. To understand the potential of diet for the preservation of hippocampal function, we investigated the effects of dietary supplementation with resveratrol (RES) or docosahexaenoic acid (DHA), or their combination, on hippocampal gene expression in adult C57BL/6 mice. Animals in the supplemented group received either 50 mg/kg/day of RES or DHA, while the combination group received 50 mg/kg/day of each supplement. Dietary supplements were mixed with the AIN93G diet, and supplementation lasted 6 weeks. The control group received AIN93G diet alone for the same period. At the end of the experiment, the hippocampi were processed for genome-wide gene expression and pathway analyses. Most of the genes that were significantly altered were associated with inflammatory responses as determined by pathway analysis. RES-supplemented animals showed decreased expression of IL-6 (P=.001), MAPKapk2 (P=.015), and increased expression for PI3KR2 (P=.034) and Wnt7a (P=.004) expression. DHA-supplemented animals showed a decreased IL-6 (P=.003) and an increased Wnt7a (P=.003) expression. Animals on the combination diet showed a decreased IL-6 (P=.005) and Apolipoprotien E (ApoE) (P=.035) expression. Our findings demonstrate that hippocampal gene expression is significantly altered by all three dietary supplementation regimes. Moreover, our analysis indicates that RES and DHA likely exert their beneficial effects through antiinflammatory mechanisms.     

DNA Polymerases that Propagate the Eukaryotic DNA Replication Fork

Abstract

Three DNA polymerases are thought to function at the eukaryotic DNA replication fork. Currently, a coherent model has been derived for the composition and activities of the lagging strand machinery. RNA-DNA primers are initiated by DNA polymerase α -primase. Loading of the proliferating cell nuclear antigen, PCNA, dissociates DNA polymerase α and recruits DNA polymerase δ and the flap endonuclease FEN1 for elongation and in preparation for its requirement during maturation, respectively. Nick translation by the strand displacement action of DNA polymerase δ, coupled with the nuclease action of FEN1, results in processive RNA degradation until a proper DNA nick is reached for closure by DNA ligase I. In the event of excessive strand displacement synthesis, other factors, such as the Dna2 nuclease/helicase, are required to trim excess flaps. Paradoxically, the composition and activity of the much simpler leading strand machinery has not been clearly established. The burden of evidence suggests that DNA polymerase ε normally replicates this strand, but under conditions of dysfunction, DNA polymerase δ may substitute.     

Exome sequencing in multiplex families with left-sided cardiac defects has high yield for disease gene discovery

Congenital heart disease (CHD) is a common group of birth defects with a strong genetic contribution to their etiology, but historically the diagnostic yield from exome studies of isolated CHD has been low. Pleiotropy, variable expressivity, and the difficulty of accurately phenotyping newborns contribute to this problem. We hypothesized that performing exome sequencing on selected individuals in families with multiple members affected by left-sided CHD, then filtering variants by population frequency, in silico predictive algorithms, and phenotypic annotations from publicly available databases would increase this yield and generate a list of candidate disease-causing variants that would show a high validation rate. In eight of the nineteen families in our study (42%), we established a well-known gene/phenotype link for a candidate variant or performed confirmation of a candidate variant’s effect on protein function, including variants in genes not previously described or firmly established as disease genes in the body of CHD literature: BMP10, CASZ1, ROCK1 and SMYD1. Two plausible variants in different genes were found to segregate in the same family in two instances suggesting oligogenic inheritance. These results highlight the need for functional validation and demonstrate that in the era of next-generation sequencing, multiplex families with isolated CHD can still bring high yield to the discovery of novel disease genes.