Hypertension in Autosomal Dominant Polycystic Kidney Disease: A Clinical and Basic Science Perspective

Cardiovascular complications are major causes of morbidity and mortality in patients with autosomal dominant polycystic kidney disease (ADPKD). In particular, hypertension is insidious and remains a continuous problem that evolves during the course of the disease. Hypertension in ADPKD has been associated with abnormality in the renin-angiotensin-aldosterone system (RAAS). Early vascular changes have also been reported in young ADPKD patients. In addition, the cellular functions of mechanosensory cilia within vascular system have emerged recently. The basic and clinical perspectives of RAAS, vascular remodeling and sensory cilia are reviewed with regard to hypertension in ADPK

‘Foresting’ the grassland: Historical management legacies in forest-grassland mosaics in southern India, and lessons for the conservation of tropical grassy biomes

Colonial encounters with tropical ecosystems were primarily driven by profit-oriented management practices; witness the extensive network of timber and forestry practices that were set up across colonial India. In contrast, the colonial engagement with the montane forest-grassland mosaics of the higher reaches of the Western Ghats in southern India was marked by intensive investment in vegetation management by colonial foresters that yielded no profits. In this archival study, we trace the history of extensive vegetation transformation in this landscape from the early nineteenth to the early twentieth century. We show how the misperception that the grasslands within this mosaic must have resulted from tree felling, fire-setting and buffalo grazing by indigenous communities led colonial foresters into a century-long effort at ‘foresting’ the grasslands, primarily through large-scale planting of exotic tree species. These efforts persisted despite economic losses and ecological evidence that native tree seedlings planted in the grasslands repeatedly failed to establish. These policies continued unabated into the late twentieth century in newly independent India. Today, the once picturesque landscapes of these ancient forest-grassland mosaics are diminished by large-scale plantations of exotic species. Some of these species have become invasive and pose significant threats to the remnant natural grasslands. While this historical narrative is set in the forest-grassland mosaics of southern India, it finds striking parallels in the current day, with grasslands and savannas globally threatened by the misperception that they are ‘degraded ecosystems’ that can be ‘forested’ or converted to other ‘productive’ land uses. We suggest that this case history portends the potential fates of many of earth's threatened tropical grasslands and savannas

Faster Acquisition Technique for Software-defined GPS Receivers

Acquisition is a most important process and a challenge task for identifying visible satellites, coarse values of carrier frequency, and code phase of the satellite signals in designing software defined Global positioning system (GPS) receiver. This paper presents a new, simple, efficient and faster GPS acquisition via sub-sampled fast Fourier transform (ssFFT). The proposed algorithm exploits the recently developed sparse FFT (or sparse IFFT) that computes in sub-linear time. Further it uses the property of fourier transforms (FT): Aliasing a signal in the time domain corresponds to sub-sampling it in the frequency domain, and vice versa. The ssFFT is an FFT algorithm that computes sub-sampled version of the data by an integer factor ‘d’, and hence, the computational complexity is proportionately reduced by a factor of ‘d log d’ compared to conventional FFT-based algorithms for any length of the input GPS signal. The simulation results show that the proposed ssFFT based GPS acquisition computation is 8.5571 times faster than the conventional FFT-based acquisition computation time. The implementation of this method in an FPGA provides very fast processing of incoming GPS samples that satisfies real-time positioning requirements.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.5-11, DOI:http://dx.doi.org/10.14429/dsj.65.557

Historical and Projected Surface Temperature over India during the 20th and 21st century.

Surface Temperature (ST) over India has increased by ~0.055 K/decade during 1860-2005 and follows the global warming trend. Here, the natural and external forcings (e.g., natural and anthropogenic) responsible for ST variability are studied from Coupled Model Inter-comparison phase 5 (CMIP5) models during the 20th century and projections during the 21st century along with seasonal variability. Greenhouse Gases (GHG) and Land Use (LU) are the major factors that gave rise to warming during the 20th century. Anthropogenic Aerosols (AA) have slowed down the warming rate. The CMIP5 projection over India shows a sharp increase in ST under Representative Concentration Pathways (RCP) 8.5 where it reaches a maximum of 5 K by the end of the 21st century. Under RCP2.6 emission scenarios, ST increases up to the year 2050 and decreases afterwards. The seasonal variability of ST during the 21st century shows significant increase during summer. Analysis of rare heat and cold events for 2080-2099 relative to a base period of 1986-2006 under RCP8.5 scenarios reveals that both are likely to increase substantially. However, by controlling the regional AA and LU change in India, a reduction in further warming over India region might be achieved

The retinal and perceived locus of fixation in the human visual system

Due to the dramatic difference in spatial resolution between the central fovea and the surrounding retinal regions, accurate fixation on important objects is critical for humans. It is known that the preferred retinal location (PRL) for fixation of healthy human observers rarely coincides with the retinal location with the highest cone density. It is not currently known, however, whether the PRL is consistent within an observer or is subject to fluctuations and, moreover, whether observers' subjective fixation location coincides with the PRL. We studied whether the PRL changes between days. We used an adaptive optics scanning laser ophthalmoscope to project a Maltese cross fixation target on an observer's retina and continuously imaged the exact retinal location of the target. We found that observers consistently use the same PRL across days, regardless of how much the PRL is displaced from the cone density peak location. We then showed observers small stimuli near the visual field location on which they fixated, and the observers judged whether or not the stimuli appeared in fixation. Observers' precision in this task approached that of fixation itself. Observers based their judgment on both the visual scene coordinates and the retinal location of the stimuli. We conclude that the PRL in a normally functioning visual system is fixed, and observers use it as a reference point in judging stimulus locations.Peer reviewe

Complete Mapping of Divergent Amino Acids Responsible for Differential Ligand Binding of Folate Receptors α and β

The folate receptor (FR) type alpha may be distinguished from FR-beta by its higher affinity for the circulating folate coenzyme, (6S)-5-methyltetrahydrofolate (5-CH3H4folate), and its opposite stereospecificity for reduced folate coenzymes. Previous studies showed that a single leucine to alanine substitution at position 49 of the mature protein sequence is responsible for the functional divergence of FR-beta (Shen, F., Zheng, X., Wang, H., and Ratnam, M. (1997) Biochemistry 36, 6157-6163); however, the results also indicated that the minimum requirement for conversion of FR-beta to the functional equivalent of FR-alpha should include amino acid substitution(s) downstream of residue 92 in addition to mutation of L49A. To pinpoint those residues, chimeric FR-betaL49A/FR-alpha constructs including progressively shorter segments of FR-alpha downstream of position 92 as well as selected point mutants were studied. Simultaneous substitution of Leu-49, Phe-104, and Gly-166 in FR-beta with the corresponding FR-alpha residues Ala, Val, and Glu, respectively, reconstituted the ligand binding characteristics of FR-alpha. The results also exclude a role for other residues in FR-alpha in determining its functional divergence. A homology model of FR-alpha based on the three-dimensional structure of the chicken riboflavin-binding protein is used to show the position of residues 49, 104, and 166 in relation to the hydrophobic cleft corresponding to the riboflavin-binding pocket

Ants, fire, and bark traits affect how African savanna trees recover following damage

Bark damage resulting from elephant feeding is common in African savanna trees with subsequent interactions with fire, insects, and other pathogens often resulting in tree mortality. Yet, surprisingly little is known about how savanna trees respond to bark damage. We addressed this by investigating how the inner bark of marula (Sclerocarya birrea), a widespread tree species favoured by elephants, recovers after bark damage. We used a long‐term fire experiment in the Kruger National Park to measure bark recovery with and without fire. At 24 months post‐damage, mean wound closure was 98, 92, and 72%, respectively, in annual and biennial burns and fire‐exclusion treatments. Fire exclusion resulted in higher rates of ant colonization of bark wounds, and such ant colonization resulted in significantly lower bark recovery. We also investigated how ten common savanna tree species respond to bark damage and tested for relationships between bark damage, bark recovery, and bark traits while accounting for phylogeny. We found phylogenetic signal in bark dry matter content, bark N and bark P, but not in bark thickness. Bark recovery and damage was highest in species which had thick moist inner bark and low wood densities (Anacardiaceae), intermediate in species which had moderate inner bark thickness and wood densities (Fabaceae) and lowest in species which had thin inner bark and high wood densities (Combretaceae). Elephants prefer species with thick, moist inner bark, traits that also appear to result in faster recovery rates

Activity of radon (222Rn) in the lower atmospheric surface layer of a typical rural site in south India

Analysis of one year measurements of in situ radon (222Rn) and its progenies along with surface air temperature, relative humidity and pressure near to the Earth’s surface has been carried out for the first time at the National Atmospheric Research Laboratory (NARL, 13.5∘N and 79.2∘E) located in a rural site in Gadanki, south India. The dataset was analysed to understand the behaviour of radon in relation to the surface air temperature and relative humidity at a rural site. It was observed that over a period of the 24 hours in a day, the activity of radon and its progenies reaches a peak in the morning hours followed by a remarkable decrease in the afternoon hours. Relatively, a higher concentration of radon was observed at NARL during fair weather days, and this can be attributed to the presence of rocky hills and dense vegetation surrounding the site. The high negative correlation between surface air temperature and activity of radon (R = – 0.70, on an annual scale) suggests that dynamical removal of radon due to increased vertical mixing is one of the most important controlling processes of the radon accumulation in the atmospheric surface layer. The annual averaged activity of radon was found to be 12.01±0.66 Bq m−3 and 4.25±0.18 Bq m−3 for its progenies, in the study period

Efficient removal of methyl orange using magnesium oxide nanoparticles loaded onto activated carbon

ABSTRACT. In this work, an activated carbon composite made with magnesium oxide nanoparticles (MgONP-AC) was effectively utilized for methyl orange (MO) adsorption. The effect of pH (6-10), mass of MgONP-AC (0.1-0.3 g/L), initial MO concentration (10-30 mg/L), and temperature (283-323 K) on MO removal was investigated using a central rotatable composite experimental design based on the response surface technique (RSM) at an equilibrium agitation period of 60 min. The studies predicted the optimal MO removal of 98.99% at pH 7.68, MgONP-AC dosage of 0.24 g/L, and starting MO concentration of 15 mg/L, and temperature of 313 K. Furthermore, an artificial neural network (ANN) was utilized to simulate MO adsorption, and it properly predicted MO removal using mean squared error (MSE) and R2 for the testing data. The ANN predicts a maximum removal of 99.63% with ANN with R2 = 0.9926. The kinetic results suited the pseudo-second order kinetic equation, and the data from the equilibrium investigations corresponded well with the Langmuir isotherm (maximum uptake capacity qmax = 346 mg/g). Endothermic, spontaneous, and physical adsorption were discovered during the thermodynamic investigations.   KEY WORDS: Adsorption, Artificial neural network, Experimental design, isotherms, Kinetics, Methyl orange, MgONP-AC   Bull. Chem. Soc. Ethiop. 2022, 36(3), 531-544.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i3.