Lab-on-a-Chip Device for Hydrogen Sulfide Sensing in Biomedical and Environmental Applications Using Electrochemical Approach

2015 ◽  
Author(s):  
A. Baniya ◽  
S. Thapa ◽  
E. Borquist ◽  
D. Bailey ◽  
D. Wood ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Direct Detection ◽  
Sulfide Oxidation ◽  
Lab On A Chip ◽  
Electrode System ◽  
Sulfide Concentration ◽  
Pt Electrodes ◽  
Electrochemical Approach ◽  
And Performance

Hydrogen sulfide (H2S) is rapidly emerging as a biologically significant signaling molecule. In recent studies, sulfide level in blood or plasma has been reported to be in the concentration between 10 and 300 μM suggesting it acts in various diseases. This work reports progress on a new Lab-on-a-Chip (LOC) device for these applications. The uniquely designed, hand-held device uses advanced liberation chemistry that releases H2S from liquid sample and an electrochemical approach to detect sulfide concentration from the aqueous solution. The device itself consists of three distinct layers of Polydimethylsiloxane (PDMS) structures and a three electrode system for direct and rapid H2S concentration measurement. In this work specifically, the oxidation of sulfide at the gold (Au) and platinum (Pt.) electrodes has been examined. This is the first known application of electrochemical H2S sensing in an LOC application. The analytical utility and performance of the device has been assessed through direct detection using chronoamperometry (CA) scan and cyclic voltammetry (CV). An electrocatalytic sulfide oxidation signal has been recorded for sulfide concentration range vs, Ag/AgCl at different pH buffers at the trapping chamber. The calibration curve in the range 1 μM to 1 M was obtained using this electrode setup. The detection limit was found to be 0.1 μM. This device shows promise for providing fast and inexpensive determination of H2S concentration in aqueous samples.

Roots as a site of hydrogen sulfide uptake in the hydrocarbon seep vestimentiferan Lamellibrachia sp

1999 ◽  
Vol 202 (17) ◽  
pp. 2245-2257 ◽  
Author(s):  
D. Julian ◽  
F. Gaill ◽  
E. Wood ◽  
A.J. Arp ◽  
C.R. Fisher
Keyword(s):  
Hydrogen Sulfide ◽  
Total Mass ◽  
Sea Water ◽  
Tube Wall ◽  
Structural Characteristics ◽  
Sulfide Oxidation ◽  
Sulfide Concentration ◽  
Hydrocarbon Seep ◽  
Respiratory Organ ◽  
Root Tube

Vestimentiferan tubeworms have no mouth or gut, and the majority of their nutritional requirements are provided by endosymbiotic bacteria that utilize hydrogen sulfide oxidation to fix CO(2) into organic molecules. It has been assumed that all vestimentiferans obtain the sulfide, O(2) and CO(2) needed by the bacteria across the plume (gill) surface, but some live in locations where very little sulfide is available in the sea water surrounding the plume. We propose that at least some of these vestimentiferans can grow a posterior extension of their body and tube down into the sea-floor sediment, and that they can use this extension, which we call the ‘root’, to take up sulfide directly from the interstitial water. In this study of the vestimentiferan Lamellibrachia sp., found at hydrocarbon seeps in the Gulf of Mexico at depths of approximately 700 m, we measured seawater and interstitial sulfide concentrations in the hydrocarbon seep habitat, determined the structural characteristics of the root tube using transmission electron microscopy, characterized the biochemical composition of the tube wall, and measured the sulfide permeability of the root tube. We found that, while the sulfide concentration is less than 1 (μ)mol l(−)(1) in the sea water surrounding the gills, it can be over 1.5 mmol l(−)(1) at a depth of 10–25 cm in sediment beneath tubeworm bushes. The root tube is composed primarily of giant (β)-chitin crystallites (12–30 % of total mass) embedded in a protein matrix (50 % of total mass). Root tubes have a mean diameter of 1.4 mm, a mean wall thickness of 70 (μ)m and can be over 20 cm long. The tubeworm itself typically extends its body to the distal tip of the root tube. The root tube wall was quite permeable to sulfide, having a permeability coefficient at 20 degrees C of 0. 41×10(−)(3)cm s(−)(1), with root tube being 2.5 times more permeable to sulfide than trunk tube of the same diameter. The characteristics of the root suggest that it reaches down to the higher sulfide levels present in the deeper sediment and that it functions to increase the surface area available for sulfide uptake in a manner analogous to a respiratory organ.

scholarly journals DNA probes and PCR for diagnosis of parasitic infections.

1995 ◽  
Vol 8 (1) ◽  
pp. 113-130 ◽  
Author(s):  
J B Weiss
Keyword(s):  
Direct Detection ◽  
High Sensitivity ◽  
Clinical History ◽  
Dna Probe ◽  
Parasitic Infections ◽  
Diagnostic Assays ◽  
Reporter Probe ◽  
History Of ◽  
And Performance

DNA probe and PCR-based assays to identify and detect parasites are technically complex; however, they have high sensitivity, directly detect parasites independent of the immunocompetence or previous clinical history of the patient, and can distinguish between organisms that are morphologically similar. Diagnosis of parasites is often based on direct detection by microscopy, which is insensitive and laborious and can lack specificity. Most PCR-based assays were more sensitive than DNA probe assays. The development of PCR-based diagnostic assays requires multiple steps following the initial selection of oligonucleotide primers and reporter probe. Generally, the ability to detect the DNA of one parasite was attained by PCR; however, advances in the preparation of samples for PCR (extraction of DNA while removing PCR inhibitors) will be required to achieve that sensitivity with human specimens. Preliminary PCR systems have been developed for many different parasites, yet few have been evaluated with a large number of clinical specimens and/or under field conditions. Those evaluations are essential for determination of clinical and field utility and performance and of the most appropriate application of the assay. Several situations in which PCR-based diagnosis will result in epidemiologic, medical, or public health advances have been identified.

The Frequency of Occurrence of Handwriting Performance Features Used to Predict Whether Questioned Signatures are Simulated

2018 ◽  
Vol 28 ◽  
pp. 35-42
Author(s):  
David Black ◽  
Bryan Found ◽  
Doug Rogers
Keyword(s):  
Large Population ◽  
Quality Parameters ◽  
Frequency Of Occurrence ◽  
Relative Speed ◽  
Simulation Process ◽  
Spatial Features ◽  
And Performance ◽  
Document Examiners ◽  
Line Trace

Forensic Document Examiners (FDEs) examine the physical morphology and performance attributes of a line trace when comparing questioned to specimen handwriting samples for the purpose of determining authorship. Along with spatial features, the elements of execution of the handwriting are thought to provide information as to whether or not a questioned sample is the product of a disguise or simulation process. Line features such as tremor, pen-lifts, blunt beginning and terminating strokes, indicators of relative speed, splicing and touch ups, are subjectively assessed and used in comparisons by FDEs and can contribute to the formation of an opinion as to the validity of a questioned sample of handwriting or signatures. In spite of the routine use of features such as these, there is little information available regarding the relative frequency of occurrence of these features in populations of disguised and simulated samples when compared to a large population of a single individual’s signature. This study describes a survey of the occurrence of these features in 46 disguised signatures, 620 simulated signatures (produced by 31 different amateur forgers) and 177 genuine signatures. It was found that the presence of splices and touch-ups were particularly good predictors of the simulation process and that all line quality parameters were potentially useful contributors in the determination of the authenticity of questioned signatures. Purchase Article - $10

Fluorescence chemosensors for hydrogen sulfide detection in biological systems

The Analyst ◽  
2015 ◽  
Vol 140 (6) ◽  
pp. 1772-1786 ◽  
Author(s):  
Zhi Guo ◽  
Guiqiu Chen ◽  
Guangming Zeng ◽  
Zhongwu Li ◽  
Anwei Chen ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Biological Systems ◽  
Sulfate Reducing Bacteria ◽  
Fluorescence Sensing ◽  
Sulfate Reducing ◽  
Potential Applications ◽  
Reducing Bacteria

The development of H2S fluorescence-sensing strategies and their potential applications in the determination of sulfate-reducing bacteria activity.

scholarly journals PSIX-9 Impacts of bunk management on feedlot performance, carcass characteristics, hydrogen sulfide concentration and blood oxygen saturation in steers fed 25 or 50% modified distillers grains plus solubles

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 422-422
Author(s):  
Rebecca L Moore ◽  
Cierrah J Kassetas ◽  
Leslie A LeKatz ◽  
Bryan W Neville
Keyword(s):  
Hydrogen Sulfide ◽  
Oxygen Saturation ◽  
Management Strategy ◽  
Distillers Grains ◽  
Feed Ratio ◽  
Sulfide Concentration ◽  
Blood Oxygen ◽  
Blood Oxygen Saturation ◽  
Feedlot Performance ◽  
Arterial Blood

Abstract One hundred and twenty-six yearling angus steers (initial body weight 445.87 ± 7.13 kg) were utilized in a 2 x 2 factorial design to evaluate the impacts of bunk management and modified distillers grains plus solubles (mDGS) inclusion on feedlot performance, hydrogen sulfide concentrations and blood oxygen saturation. Treatments included bunk management strategy either control bunk management (CON; clean bunks at the time of next day’s feeding) or long bunk management (LONG; feed remaining at time of next day’s feeding), and two inclusion rates of mDGS either 25% or 50% (DM Basis). On d 0, 7, 14, 21, 28 and 35 rumen gas samples were collected via rumenocentesis, and arterial blood samples were collected on two steers from each pen. No differences (P ≥ 0.09) were observed for dry matter intake, average daily gain and gain-to-feed ratio for bunk management or mDGS inclusion. Hot carcass weight, ribeye area, marbling score and quality grade were not affected (P ≥ 0.48) by either bunk management or mDGS inclusion. Back fat was greater (P = 0.04) for CON steers compared to LONG (1.30 vs 1.12 ± 0.05cm, respectively), but was not affected (P = 0.59) by mDGS inclusion. Steers on CON had greater (P = 0.03) yield grades compared to LONG (3.21 vs 2.96 ± 0.11, respectively). Bunk management strategy did not impact hydrogen sulfide concentrations or blood oxygen saturation (P = 0.82). Hydrogen sulfide concentrations increased (P < 0.001) with increasing mDGS inclusion. Blood oxygen saturation was influenced by day of sampling (P = 0.01). Blood oxygen saturation was not affected (P = 0.07) by mDGS inclusion. The fact that ruminal hydrogen sulfide concentrations increased while blood oxygen saturation remained similar raises questions about the quantity of hydrogen sulfide and metabolic fate of excess hydrogen sulfide in the blood of ruminant animals.

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