Molecular and cellular insights into iron regulation

The iron hormone hepcidin is regarded as the main iron homeostatic regulator in the human body. It is predominantly produced by hepatocytes in response to systemic iron excess. However, since the cellular and molecular mechanisms involved in hepcidin expression are not fully understood, this project involved studying hepcidin expression and the role of the pro-region of the hepcidin prohormone in regulation of iron homeostasis. Iron overdose in Chinese hamster ovary-transferrin receptor variant (CHO TRVb1) cells resulted in increased hepcidin peptide secretion after 30 min and 2 hours (p<0.03) as well as 24 and 48 hours (p<0.01). Also, partial characterisation of the previously unknown CHO-gene sequences of Hfe, Slc40-a1 and Irp2, was achieved. To determine the effect of intracellular iron overload on hepcidin expression, recombinant transferrin receptor 1 (rec-TfR1) HepG2 cells were created which express modified TfR1 to maximise iron uptake. Upon holotransferrin (5 g/L) treatment these cells showed significantly increased iron uptake which was in contrast to the response by Wt HepG2 cells. Also, it was shown for the first time that hepcidin peptide secretion increased upon iron overdose to HepG2 cells after 30 min, 2,4,24 and 48 hours (p<0.05). Also, holotransferrin treatment (5 g/L) increased hepcidin mRNA levels; in Wt HepG2 cells by 0.6 fold (on average) after 30 min, 2,4,6 and 24 hours and in rec-TfR1 HepG2 cells by 0.5 fold after 2 h (p<0.02). Gene expression studies of TfR1, SLC40-A1, and HFE upon iron overdose showed opposing functionalities of TfR1 and SLC40-A1 in maintaining intracellular iron homeostasis and emphasised the significance of HFE in hepcidin induction. Additionally, localisation studies with the pre-pro derivative of preprohepcidin identified its presence in the nucleus, suggesting its involvement in the gene regulation process and thus possible participation in maintaining iron homeostasis. In conclusion, rec-TfR1 HepG2 cells partially resemble haemochromatotic cells and the findings indicate that hepcidin regulation involves the interaction between several iron-related genes and the extracellular and intracellular iron levels

Characterization of a turbomolecular-pumped magnetic sector mass spectrometer

A Perkin Elmer MGA-1200, turbomolecular-pumped, magnetic sector, multiple gas analyzer mass spectrometer with modified inlet for fast response was characterized for the analysis of hydrogen, helium, oxygen and argon in nitrogen and helium background gases. This instrument was specially modified for the Vanderberg AFB SLC-6 Hydrogen Disposal Test Program, as a part of the Hydrogen Sampling System (H2S2). Linearity, precision, drift, detection limits and accuracy among other analytical parameters for each of the background gas were studied to evaluate the performance of the instrument. The result demonstrates that H2S2 mass spectrometer is a stable instrument and can be utilized for the quantitative analytical determination of hydrogen, helium, oxygen and argon in nitrogen and helium background gases

Rural buyers' perception about mosquito repellants

Mosquito repellants prevent mosquito bites and prevention of "man-mosquito contact" is a critical factor in transmission and spread of any disease through mosquitoes particularly in rural area. There has been a long standing 'bias' towards rural buyers. The rural markets are considered rigid in the nature but it is not the case in real sense. Marketing to rural buyers is not only a challenge to the marketers but to the manufacturers, communicators, national planners and economists as well. That is why it has been necessary to understand the various aspects of selected rural areas and consumption pattern for such a fast growing market i.e. mosquito repellants and rural buyers’ perception towards such urban products. The present paper aims to find out the factors influencing the purchase decisions of rural buyers for mosquito repellants and to study the perceptions of present and potential rural buyers' of selected mosquito repellant brands.mosquito, repellent, malaria, rural market, buyers

H-MAC: A Hybrid MAC Protocol for Wireless Sensor Networks

In this paper, we propose a hybrid medium access control protocol (H-MAC) for wireless sensor networks. It is based on the IEEE 802.11's power saving mechanism (PSM) and slotted aloha, and utilizes multiple slots dynamically to improve performance. Existing MAC protocols for sensor networks reduce energy consumptions by introducing variation in an active/sleep mechanism. But they may not provide energy efficiency in varying traffic conditions as well as they did not address Quality of Service (QoS) issues. H-MAC, the propose MAC protocol maintains energy efficiency as well as QoS issues like latency, throughput, and channel utilization. Our numerical results show that H-MAC has significant improvements in QoS parameters than the existing MAC protocols for sensor networks while consuming comparable amount of energy.Comment: 10 pages, IJCNC Journal 201

Overcoming Recession through Effective Business Communication Approaches (A Study in Indian Scenario)

No business activity can be completed without effective business communication network. The stage of economic turmoil is the most important time for any organization to regroup its strategy. At this juncture, strong, transparent and constant internal and external communication networks play a vital role. The global meltdown is a blessing in disguise for the organizations to invigorate their business communication network. The present paper aims to study multifarious approaches of Business Communication applied by Indian Organizations to combat the turbulent period of recession in a successful manner.

Identifying Keystone Species in the Human Gut Microbiome from Metagenomic Timeseries using Sparse Linear Regression

Human associated microbial communities exert tremendous influence over human health and disease. With modern metagenomic sequencing methods it is possible to follow the relative abundance of microbes in a community over time. These microbial communities exhibit rich ecological dynamics and an important goal of microbial ecology is to infer the interactions between species from sequence data. Any algorithm for inferring species interactions must overcome three obstacles: 1) a correlation between the abundances of two species does not imply that those species are interacting, 2) the sum constraint on the relative abundances obtained from metagenomic studies makes it difficult to infer the parameters in timeseries models, and 3) errors due to experimental uncertainty, or mis-assignment of sequencing reads into operational taxonomic units, bias inferences of species interactions. Here we introduce an approach, Learning Interactions from MIcrobial Time Series (LIMITS), that overcomes these obstacles. LIMITS uses sparse linear regression with boostrap aggregation to infer a discrete-time Lotka-Volterra model for microbial dynamics. We tested LIMITS on synthetic data and showed that it could reliably infer the topology of the inter-species ecological interactions. We then used LIMITS to characterize the species interactions in the gut microbiomes of two individuals and found that the interaction networks varied significantly between individuals. Furthermore, we found that the interaction networks of the two individuals are dominated by distinct "keystone species", Bacteroides fragilis and Bacteroided stercosis, that have a disproportionate influence on the structure of the gut microbiome even though they are only found in moderate abundance. Based on our results, we hypothesize that the abundances of certain keystone species may be responsible for individuality in the human gut microbiome