Wireless body area networks for intra-spacesuit communications: modeling, measurements and wearable antennas

Doctor of PhilosophyDepartment of Electrical and Computer EngineeringWilliam B. KuhnBalasubramaniam NatarajanWireless body area networks (WBANs) are an important part of the developing internet of things (IOT). NASA currently uses space suits with wired sensors to collect limited biomedical data. Continuous monitoring and collecting more extensive body vital signs is important to assess astronaut health. This dissertation investigates wireless biomedical sensor systems that can be easily incorporated into future space suits to enable real time astronaut health monitoring. The focus of the work is on the radio-wave channel and associated antennas. We show that the space suit forms a unique propagation environment where the outer layers of the suit’s thermal micrometeoroid garment are largely radio opaque. This environment can be modeled as a coaxial one in which the body itself plays the role of the coax center conductor while the space suit shielding materials play the role of the outer shield. This model is then validated through simulations and experiments. Selecting the best frequency of operation is a complex mixture of requirements, including frequency allocations, attenuation in propagation, and antenna size. We investigate the propagation characteristics for various frequency bands from 315 MHz to 5.2 GHz. Signal attenuation is analyzed as a function of frequency for various communication pathways through 3D simulations and laboratory experiments. Small-scale radio channel results indicate that using lower frequency results in minimal path loss. On the other hand, measurements conducted on a full-scale model suggest that 433 MHz and 2400 MHz yield acceptable path loss values. Propagation between the left wrist and left ankle yielded the worst overall path loss, but signals were still above –100 dBm in raw measurements for a 0dBm transmission indicating that the intra-suit environment is conducive to wireless propagation. Our findings suggest that the UHF bands are best candidate bands since there is interplay between the body conductivity favoring lower frequencies, and the difficulty of coupling RF energy into and out of the channel using suitably sized antennas favoring higher frequencies. Finally, a new self-shielded folded bow-tie antenna is proposed that can be a promising choice for the general area of WBAN technologies as well as potential new space suit environments

Study of Some Toxic Effects of Diminazine in Vitro

Background: The trypanocidal agent, diminazine have been shown to produce some toxic effects such as itching, hypotension and gastrointestinal disturbances among the migratory domestic animals, especially in camels during the dry season in South-western Sudan.                                                                  Objective: The present study was an attempt to explain some toxic effects of diminazine in vitro. Methods: A number of qualitative and quantitative experiments have been done to elucidate these mechanisms using different concentrations of diminazine.  Results: Incubation of different concentrations of diminazine with rat lung chops and their intraperitoneal administration, produced incubates that potently stimulated the isolated guinea-pig ileum. The obtained contractions were dosedependent and effectively blocked by the anti-histamine, diphenhydramine. The yielded incubated mixtures when developed on paper chromatography with authentic samples showed two spots with Rf values and colours similar to those of heparin and histamine when sprayed with ninhydrin or exposed to iodine vapour. The extent to which diminazine released histamine was determined by measuring the concentrations of the released histamine using the three-point assay. The addition of EDTA, diltiazem and dinitrophenol separately to the incubated mixtures indicated that the release of histamine and the accompanied heparin was calcium-and energy-dependent, most probably by exocytosis and damaging the lung and peritoneal mast cells.  When tested on isolated rabbit jejunum, diminazine was found to potentiate the effect of histamine with pA1/2 value of 5.4 ± 0.13 compared to 5.6 ± 0.15 for aminoguanidine, the standard diamine oxidase inhibitors. Conclusion: Diminazine was found to have a potent histamine releasing capacity. These findings indicated that the severe toxic effects produced by diminazine might be due to its ability to release histamine and/or potentiating its effects.&nbsp

CLINICAL HYPOGLYCEMIC EFFECTS OF ALLIUM CEPA (RED ONION) IN TYPE 2 DIABETIC PATIENTS

Background: Type 2 diabetes mellitus results from defects in insulin secretion and/or insulin action or both. Objectives: The present study was conducted to investigate the hypoglycemic effects of Allium cepa in patients with type 2 diabetes mellitus.   Results: In type 2 diabetic patients (n=21) the administration of crude Allium cepa (100g) markedly reduced fasting blood glucose levels by 40 mg/dl 4 hours later, compared to glibenclamide (81 mg/dl). Also Allium cepa significantly reduced the induced hyperglycemia (GTT) after ingestion of 75 grams dextrose by 159 mg/dl in the test subgroup (n=7) of type 2 diabetic patients to a point below that produced in the negative control group after 4 hours. Conclusion: Crude Allium cepa produced hypoglycemic effects, thus it could be used as a dietary supplement in management of diabetes

The Effects of Ethanolic Extract of Handal (Citrullus colocynthis L.) Fruit Pulp on Blood Glucose level in Normal Fasting Rats

Background: Citrullus colocynthis L. is a member of the family Cucurbitaceae. It is widely available in Sudan and traditionally used for treatment of skin infections, diabetes and constipation worldwide. Objectives: This study aimed to investigate the effects of ethanolic extract of C. colocynthis fruit pulp on blood glucose level in normal fasting rats. Method: Two groups of rats, each of twenty one were used to study the effects of the extract (300 mg/kg/ml) on fasting blood glucose level (BGL) and glucose tolerance test (GTT). Results: The oral administration of ethanolic extract of C. colocynthis fruit pulp resulted in a sudden drop in BGL of normal fasting rats after four hours. This was accompanied by some toxic effects appeared as severe diarrhea, followed by deaths of some rats (2/7). Moreover, the administration of the extract did not exhibit a remarkable reduction or improvement in the induced hyperglycemia.  Conclusion: This study showed that, ethanolic extract of C. colocynthis fruit pulp reduced the BGL without significant hypoglycemic effect and the extract appeared to be highly toxic.

Quantifying the effects of temperature and noise on attention-level using EDA and EEG sensors

Most people with Autism Spectrum Disorder (ASD) experience atypical sensory modality and need help to self-regulate their sensory responses. Results of a pilot study are presented here where temperature, noise types and noise levels are used as independent variables. Attention-based tests (ABTs), Electrodermal Activity (EDA) and Electroencephalography (EEG) sensors are used as dependent variables to quantify the effects of temperature and noise. Based on the outcome of the analyses, it is feasible to use off-the-shelf sensors to recognize physiological changes, indicating a possibility to develop sensory management recommendation interventions to support people with ASD

An overview of anti-diabetic plants used in Gabon: Pharmacology and Toxicology

© 2017 Elsevier B.V. All rights reserved.Ethnopharmacological relevance: The management of diabetes mellitus management in African communities, especially in Gabon, is not well established as more than 60% of population rely on traditional treatments as primary healthcare. The aim of this review was to collect and present the scientific evidence for the use of medicinal plants that are in currect by Gabonese traditional healers to manage diabetes or hyperglycaemia based here on the pharmacological and toxicological profiles of plants with anti-diabetic activity. There are presented in order to promote their therapeutic value, ensure a safer use by population and provide some bases for further study on high potential plants reviewed. Materials and methods: Ethnobotanical studies were sourced using databases such as Online Wiley library, Pubmed, Google Scholar, PROTA, books and unpublished data including Ph.D. and Master thesis, African and Asian journals. Keywords including ‘Diabetes’ ‘Gabon’ ‘Toxicity’ ‘Constituents’ ‘hyperglycaemia’ were used. Results: A total of 69 plants currently used in Gabon with potential anti-diabetic activity have been identified in the literature, all of which have been used in in vivo or in vitro studies. Most of the plants have been studied in human or animal models for their ability to reduce blood glucose, stimulate insulin secretion or inhibit carbohydrates enzymes. Active substances have been identified in 12 out of 69 plants outlined in this review, these include Allium cepa and Tabernanthe iboga. Only eight plants have their active substances tested for anti-diabetic activity and are suitables for further investigation. Toxicological data is scarce and is dose-related to the functional parameters of major organs such as kidney and liver. Conclusion: An in-depth understanding on the pharmacology and toxicology of Gabonese anti-diabetic plants is lacking yet there is a great scope for new treatments. With further research, the use of Gabonese anti-diabetic plants is important to ensure the safety of the diabetic patients in Gabon.Peer reviewedFinal Accepted Versio

A Review of Wearable Solutions for Physiological and Emotional Monitoring for Use by People with Autism Spectrum Disorder and Their Caregivers

The goal of real-time feedback on physiological changes, stress monitoring and even emotion detection is becoming a technological reality. People in their daily life experience varying emotional states, some of which are negative and which can lead to decreased attention, decreased productivity and ultimately, reduced quality of life. Therefore, having a solution that continuously monitors the physiological signals of the person and assesses his or her emotional well-being could be a very valuable tool. This paper aims to review existing physiological and motional monitoring devices, highlight their features and compare their sensing capabilities. Such technology would be particularly useful for certain populations who experience rapidly changing emotional states such as people with autism spectrum disorder and people with intellectual disabilities. Wearable sensing devices present a potential solution that can support and complement existing behavioral interventions. This paper presents a review of existing and emerging products in the market. It reviews the literature on state-of-the-art prototypes and analyzes their usefulness, clinical validity, and discusses clinical perspectives. A small number of products offer reliable physiological internal state monitoring and may be suitable for people with Autism Spectrum Disorder (ASD). It is likely that more promising solutions will be available in the near future. Therefore, caregivers should be careful in their selection of devices that meet the care-receiver’s personal needs and have strong research support for reliability and validity