Unknown Concentration Research Articles

Diagnosing the RGS11 Lung Cancer Biomarker: The Integration of Competitive Immunoassay and Isothermal Nucleic Acid Exponential Amplification Reaction.

Lung cancer is the primary cause of cancer-associated mortality worldwide, which makes the identification of reliable lung cancer biomarkers a pressing need for early diagnosis and prognosis. RGS11, which is a regulator of G-protein signaling and also a lung cancer biomarker, plays an important role in cancer-related metastasis. However, trace levels of RGS11 (in the range of pg/mL) in serum samples make it difficult to quantify using currently available enzyme-linked immunosorbent assay (ELISA) kits and, therefore, this hinders progress in the discovery of new approaches for treating lung cancer. The aim of this study is to develop a rapid, sensitive, and reliable platform for the detection of RGS11 lung cancer biomarker based on a suspension immunoassay coupled with an isothermal exponential amplification strategy. Our study was initiated by the functionalization of magnetic beads with anti-RGS11 antibodies (Ab-MB) by EDC (1-ethyl-3-(3-(dimethylamino)propyl)-carbodiimide)/NHS ( N-hydroxysulfosuccinimide) activation. Ab-MB served as a sensing probe for the competitive immunorecognitions between known concentrations of His-tag RGS11 and unknown concentrations of target RGS11 in serum. The reporter anti-His antibodies, which were modified with primers that induced an isothermal exponential amplification reaction, were subsequently introduced to the reaction mixture that resulted in the formation of immunosandwich complexes. The exponentially amplified DNA duplex that was intercalated with SYBR Green was designated as a signal reporter for the assessment of RGS11 in an inversely proportional relationship. The sensing platform was excellent for the determination of RGS11 with an exceptional detection limit of 148 fg/mL and a linear dynamic range of 0.1-10 pg/mL using a minimal sample volume (20 μL) and with a reaction time of 1.5 h. In addition, we challenged the sensing platform with RGS11-spiked samples (in 2× diluted serum), and an acceptable recovery rate (>90%) was observed. Finally, 24 clinical samples acquired from patients with advanced lung cancer (C), inflammation (I), and heart failure (H) were analyzed by this newly developed sensing platform and a commercial ELISA kit for validation. This sensing platform has potential in biomedical applications for clinically diagnosing liquid biopsy samples for patients with lung cancer. Moreover, the universal design of our proposed system is easily adapted to detect any other protein if a His-tag recombinant protein is available.

Uncertainties in Projections of the Baltic Sea Ecosystem Driven by an Ensemble of Global Climate Models

Many coastal seas worldwide are affected by human impacts such as eutrophication causing, inter alia, oxygen depletion and extensive areas of hypoxia. Depending on the region, global warming may reinforce these environmental changes by reducing air-sea oxygen fluxes, intensifying internal nutrient cycling and increasing river-borne nutrient loads. The development of appropriate management plans to effectively protect the marine environment requires projections of future marine ecosystem states. However, projections with regional climate models commonly suffer from shortcomings in the driving global General Circulation Models (GCMs). The differing sensitivities of GCMs to increased greenhouse gas concentrations affect regional projections considerably. In this study, we focused on one of the most threatened coastal seas, the Baltic Sea, and estimated uncertainties in projections due to climate model deficiencies and due to unknown future greenhouse gas concentration, nutrient load and sea level rise scenarios. To address the latter, simulations of the period 1975-2098 were performed using the initial conditions from an earlier reconstruction with the same Baltic Sea model (starting in 1850). To estimate the impacts of climate model uncertainties, dynamical downscaling experiments with four driving global models were carried out for two greenhouse gas concentration scenarios and for three nutrient load scenarios, covering the plausible range between low and high loads. The results of primary production, nitrogen fixation, and hypoxic areas show that uncertainties caused by the various nutrient load scenarios are greater than the uncertainties due to climate model uncertainties and future greenhouse gas concentrations. In all scenario simulations, a proposed nutrient load abatement strategy, i.e., the Baltic Sea Action Plan, will lead to a significant improvement in the overall environmental state. However, the projections cannot provide detailed information on the timing and the reductions of future hypoxic areas, due to uncertainties in salinity projections caused by uncertainties in projections of the regional water cycle and of the mean sea level outside the model domain.

Using near infrared measurements to evaluate NaCl and KCl in water

Spectral differences between aqueous solutions of NaCl and KCl have received minimal attention in previous research due to strong similarities between the two salts and the lack of motivation to differentiate between them. Correlations between salinity and absorbance have been developed previously with varying degrees of linearity but have not been tested to saturation. This work will demonstrate that correlating spectral measurements and the concentration of NaCl and KCl in water can be extended up to the saturation point of both salts and that solutions of these salts with unknown concentrations can be distinguished. Spectral data for samples of NaCl and KCl in single-salt solutions were collected up to saturation and correlations were developed for differentiating between solutions of the two species. These correlations were able to correctly identify the solution type for all solutions in the test set and estimate their concentrations with an average error of 0.9%.

Application of novel solid phase extraction-NMR protocols for metabolic profiling of human urine.

Metabolite identification and annotation procedures are necessary for the discovery of biomarkers indicative of phenotypes or disease states, but these processes can be bottlenecked by the sheer complexity of biofluids containing thousands of different compounds. Here we describe low-cost novel SPE-NMR protocols utilising different cartridges and conditions, on both natural and artificial urine mixtures, which produce unique retention profiles useful for metabolic profiling. We find that different SPE methods applied to biofluids such as urine can be used to selectively retain metabolites based on compound taxonomy or other key functional groups, reducing peak overlap through concentration and fractionation of unknowns and hence promising greater control over the metabolite annotation/identification process.

Predictive Soil Pollution Mapping: A Hybrid Approach for a Dataset With Outliers

Spatial regression or interpolation is widely used for predictive soil pollution mapping, which aims to estimate all unobserved soil pollution based on a finite number of sample points. However, it may be unreasonable to use spatial regression or interpolation directly for an environmental soil dataset with outliers, because the mechanism generating outlier datasets is always different from that generating normal datasets, which necessitates handling outliers separately. Therefore, a hybrid approach for estimating unknown soil pollution concentrations is developed in this paper. The hybrid approach comprises three main steps: First, spatial outlier detection is used to uncover abnormal sample points and the study area is then divided into the normal and outlier areas. Second, spatial regression and interpolation are applied to analyze the normal and outlier datasets, respectively. Finally, the results of the predictive soil pollution mapping are derived from the prediction combination of spatial regression and interpolation. An environmental dataset recording heavy metal Cd and As concentrations at Huizhou, China was selected to verify the performance of the proposed approach. The numbers of identified outlier points of heavy metal Cd and As concentrations were 16 and 13. For the prediction result of Cd, the mean square error (MSE) and mean relative error (MRE) of the hybrid approach were about 0.028 and 0.332, respectively. For the prediction result of As, the MSE and MRE of the hybrid approach were about 3.834 and 0.366, respectively. All of these values were smaller than those of models used for comparison. The result of the comparative analysis demonstrates the feasibility and effectiveness of the proposed approach.

SPECTROPHOTOMETRIC DETERMINATION OF COPPER COMPLEXES OF CHLOROPHYLLINS (E141ii)

In this study, the water-soluble green food colorant copper complexes of chlorophyllins, E141ii, as one of the most popular within the food industry was investigated. First, the spectroscopic parameters, absorbance maximum, λmax-vis, and molar absorptivities, ε, of E141ii dye were determined. The impact of the presence of aspartame, citric acid and vitamin C on the change in the positions of the absorbance maximum and change of its intensity in the visible range of the E141ii spectra also was investigated. Recorded absorption spectra was show that this dye had two absorbance maxima. The average molar absorptivities were calculated. These values of molar absorptivities were later used to quantify the unknown dye concentration in the analyzed food samples. It was found that the use of additives (vitamin C, citric acid and aspartame) does not cause a change in the positions of the absorbance maximum and change of its intensity in the visible range of the E141ii spectra. Therefore, it can be concluded that it is possible to quantify the E141ii by UV-Vis spectrophotometric method in the presence of these additives. Based on determined spectroscopic parameters, the dye concentration was calculated in green rubber candy colored with E141ii.

Bead-Based Flow-Cytometric Cell Counting of Live and Dead Bacteria.

Flow cytometry(FCM) is based on the detection of scattered light and fluorescence to identify cells with characteristics of interest. Many flow cytometers cannot precisely control the flow through its interrogation point and hence the volume and concentration of the sample cannot be immediately obtained. Here we describe the optimization and evaluation of a bead-based method for absolute cell counting applicable to basic flow cytometers without specialized counting features. Prior to the application of this method to an unknown concentration of a species of bacteria, a calibration experiment should be completed to characterize limits of detection and range of linearity with respect to the plate count method. To demonstrate the calibration process, mixtures of Escherichia coli or Staphylococcus aureus with proportions of live and dead cells ranging from 0% to 100% were prepared. These samples were stained using nucleic acid-binding dyes, and 6μm reference beads were added (LIVE/DEAD® BacLight kit). The calibration samples were analyzed using bead-based FCM as well as the agar plate count method, and the results from both methods were compared.

3D Multilayered paper- and thread/paper-based microfluidic devices for bioassays.

In this paper we describe the fabrication of novel 3D microfluidic paper-based analytical devices (3D-μPADs) and a 3D microfluidic thread/paper-based analytical device (3D-μTPAD) to detect glucose and BSA through colorimetric assays. The 3D-μPAD and 3D-μTPAD consisted of three (wax, heat pressed wax-printed paper, single-sided tape) and four (hole-punched single-sided tape, blank chromatography circles, heat-pressed wax-printed paper, hole-punched single-sided tape containing trifurcated thread) layers, respectively. The saturation curves for each assay were generated for all platforms. For the glucose assay, a solution of glucose oxidase (GOx), horseradish peroxidase, and potassium iodide was flowed through each platform and, upon contact with glucose, generated a yellow-brown color indicative of the oxidation of iodide to iodine. For the protein assay, BSA was flowed through each device and, upon contact with citrate buffer and tetrabromophenol blue, resulted in a color change from yellow to blue. The devices were dried, scanned, and analyzed yielding a correlation between either yellow intensity and glucose concentration or cyan intensity and BSA concentration. A similar glucose assay, using unknown concentrations of glucose in artificial urine, was conducted and, when compared to the saturation curve, showed good correlation between the theoretical and actual concentrations (percent differences <10%). The development of 3D-μPADs and 3D-μTPADs can further facilitate the use of these platforms for colorimetric bioassays.

An approach to determine the concentration of coloured solution using android smartphones

The purpose of this research is to determining the concentration of the coloured solution NiSO4 and to know the accuracy of smartphone application usage. Determining the concentration of a coloured solution using a smartphone can be an alternative to overcome the limitations of spectrophotometric or colorimetric instruments. An approach using the smartphone is based on hue colon is read by a smartphone application, then the data generated from the application is RGB value and will be processed to determine the concentration. Determining the concentration of the coloured solution is assisted by three standards solution and the concentration are known to make the standard curves. The methodology of this research is research and development. The results in this research have a fairly good accuracy percentage, for both unknown concentrations of NiSO4 solution the percentage of accuracy is 100% and 95% with a percent error is 0% and 5%. This indicates the application on the smartphone is suitable for use in determining the concentration of the coloured solution.

Structural, kinetic and thermodynamic characterizations of SDS-induced molten globule state of a highly negatively charged cytochrome c.

This study presents the structural, kinetic and thermodynamic characterizations of previously unknown submicellar concentrations of SDS-induced molten globule (MGSDS) state of a highly negatively charged base-denatured ferricytochrome c (UB-state) at pH ∼12.8 (±0.2). The far-UV CD, near-UV CD, ANS-fluorescence data of UB-state in the presence of different concentrations of SDS indicate that the submicellar concentrations of SDS (≤0.4 mM) transform the UB-state to MGSDS-state. The MGSDS-state has native-like α-helical secondary structure but lacks tertiary structure. The free energy change (ΔG°D) for UB→ MGSDS transition determined by far-UV CD (∼2.7 kcal mol-1) is slightly higher than those determined by fluorescence (∼2.0 kcal mol-1) at 25°C. At very low SDS and NaCl concentrations, the MGSDS-state undergoes cold denaturation. As SDS concentration is increased, the thermal denaturation temperature increases and the cold denaturation temperature decrease. Kinetic experiments involving the measurement of the CO-association rate to the base-denatured ferrocytochrome c at pH ≈12.8 (±0.2), 25°C indicate that the submicellar concentrations of SDS restrict the internal dynamics of base-denatured protein.

Quantitative measurement of selected protein biomarkers of endothelial dysfunction in plasma by micro-liquid chromatography-tandem mass spectrometry based on stable isotope dilution method

The aim of this study was to develop and validate the novel microLC/MS-MRM method for the simultaneous quantification of six proteins: angiopoietin 2 (Angpt-2), soluble form of fms-like tyrosine kinase 1 (sFLT-1), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (t-PA), endocan (ESM-1), soluble form of E-selectin (sE-sel), and one peptide: adrenomedullin (ADM) in mouse plasma. Two approaches were compared: a stable isotope dilution (SID) method- used as a reference and a modified SID (mSID) procedure. In SID strategy the calibration curves were used, whereas in mSID the ratio between the chromatogram peak area of endogenous tryptic peptides at unknown concentration to chromatogram peak area of exogenous, stable isotope-labelled internal standards (SISs) added to the sample at known concentration was calculated. The microLC/MS-MRM method in the SID approach was linear from 0.250 pmol/mL to 250 pmol/mL for Angpt-2; 5 pmol/mL to 5000 pmol/mL for sFLT-1; 2.5 pmol/mL to 5000 pmol/mL for PAI-1; 0.375 pmol/mL to 250 pmol/mL for t-PA; 0.375 pmol/mL to 187.5 pmol/mL for ESM-1; 2.5 pmol/mL to 5000 pmol/mL for sE-sel and 0.375 pmol/mL to 250 pmol/mL for ADM. LPS-induced changes in plasma assessed based on SID and mSID approaches gave comparable quantitative results and featured LPS-induced dysregulation of endothelial permeability (Angpt-2, sFLT-1), glycocalyx injury (SDC-1) accompanied by a pro-thrombotic response (PAI-1). In addition, we applied microLC/MS-MRM method with mSID strategy to analyze human plasma samples from patients with chronic myeloid leukemia (CML) and obstructive sleep apnoea (OSA) and demonstrated usefulness of the method to characterize endothelial function in humans. In conclusion, the microLC/MS-MRM method with mSID strategy applied for simultaneous quantification of protein biomarkers of endothelial function in plasma represents a novel targeted proteomic platform for the comprehensive evaluation of endothelial function in mice and humans.

Developing Paper Based Diagnostic Technique to Detect Uric Acid in Urine.

Urinary or serum uric acid concentration is an indicator of chronic kidney condition. An increase in uric acid concentration may indicate renal dysfunction. Reliable instantaneous detection of uric acid without requiring sophisticated laboratory and analytical instrumentation, such as: chromatographic and spectrophotometric methods, would be invaluable for patients with renal complication. This paper reports the early development of a simple, low-cost, instantaneous and user-friendly paper based diagnostic device (PAD) for the qualitative and quantitative detection of uric acid in urine. A colorimetric detection technique was developed based on the intensity of Prussian blue color formation on paper in presence of uric acid; the reaction rate of corresponding chemical reactions on paper surface was also studied. Based on the colorimetric signal produced on paper surface, a calibration curve was developed to detect unknown concentration of uric acid in urine. The effect of temperature on formation of color signal on paper surface was also analyzed. In this study, estimation of urinary uric acid using MATLAB coding on a windows platform was demonstrated as the use of software application and digital diagnostics. This paper-based technique is faster and less expensive compared to traditional detection techniques. The paper-based diagnostic can be integrated with a camera of smart phone, tablet computer or laptop and an image processing application (using windows/android/IOS platform) as a part of digital diagnostics. Therefore, with proper calibration, the paper-based technique can be compatible and economical to the sophisticated detection techniques used to detect urinary uric acid.

Alternative Pharmaceutical Formulation for Oral Administration of Rifampicin.

Tuberculosis (TB) is considered an emergency global public health, mainly due to the TB-HIV co-infection, bacillus dormancy stage, and emergence of resistant strains. In addition, the therapeutic toxicity and its pharmacokinetic interactions with other drugs may influence treatment non-compliance, low serum concentration of drugs, and, consequently, treatment failure. Strategies using nanotechnology represent a new tool for the therapy, since they are effective delivery systems due to the possibility of solubilization of hydrophobic compounds, enable the production of formulations for oral use, and, in addition, increase bioavailability of drugs. This study aimed to develop a nanoemulsion (NE) containing rifampicin (RIF-NE) and evaluate its in vitro antimycobacterial activity using Resazurin Microtiter Assay against three Mycobacterium tuberculosis strains: two susceptible and a multidrug-resistant. Using the hot solvent diffusion method associated with phase inversion technique was possible to develop a liquid formulation containing 500 μg/mL rifampicin (RIF), which is a hydrophobic compound, of average size 25 nm. The results showed that the minimum inhibitory concentration of the encapsulated RIF was equal to the free form of RIF, indicating that the process of production of NEs did not affect the activity of the compound. Thus, RIF-NE could be a promising alternative for oral administration of RIF, being considered a child-friendly pharmaceutical formulation. Its application could avoid the administration of unknown and/or non-ideal concentrations, being functional in the regimes of prevention and treatment of TB and, in addition, in the fight against drug resistance.

Hyperbolic subtraction method: Determination of the concentration of an analyte in the presence of an unknown interferent via spectral data.

A theoretical model to determine the concentration of an analyte in the presence of unknown interferents using spectral-type data is described. The method involves absorbance measurements at three wavelengths and the calculation of specific absorbances yielding a hyperbolic relationship between absorbance ratios and analyte concentrations. The concentration of the analyte of known spectrum can be determined in the presence of an interferent or mixture of interferents of unknown concentration(s) and spectra can be determined combining data for different sets of wavelengths. Application to indigo and isatin solutions in DMSO related to the so-called Maya blue problem is reported as an illustrative application example.

DMS oxidation and sulfur aerosol formation in the marine troposphere: a focus on reactive halogen and multiphase chemistry

Abstract. The oxidation of dimethyl sulfide (DMS) in the troposphere and subsequent chemical conversion into sulfur dioxide (SO2) and methane sulfonic acid (MSA) are key processes for the formation and growth of sulfur-containing aerosol and cloud condensation nuclei (CCN), but are highly simplified in large-scale models of the atmosphere. In this study, we implement a series of gas-phase and multiphase sulfur oxidation mechanisms into the Goddard Earth Observing System-Chemistry (GEOS-Chem) global chemical transport model – including two important intermediates, dimethyl sulfoxide (DMSO) and methane sulphinic acid (MSIA) – to investigate the sulfur cycle in the global marine troposphere. We found that DMS is mainly oxidized in the gas phase by OH (66 %), NO3 (16 %) and BrO (12 %) globally. DMS + BrO is important for the model's ability to reproduce the observed seasonality of surface DMS mixing ratio in the Southern Hemisphere. MSA is mainly produced from multiphase oxidation of MSIA by OH(aq) (66 %) and O3(aq) (30 %) in cloud droplets and aerosols. Aqueous-phase reaction with OH accounts for only 12 % of MSA removal globally, and a higher MSA removal rate is needed to reproduce observations of the MSA ∕ nssSO42- ratio. The modeled conversion yield of DMS into SO2 and MSA is 75 % and 15 %, respectively, compared to 91 % and 9 % in the standard model run that includes only gas-phase oxidation of DMS by OH and NO3. The remaining 10 % of DMS is lost via deposition of intermediates DMSO and MSIA. The largest uncertainties for modeling sulfur chemistry in the marine boundary layer (MBL) are unknown concentrations of reactive halogens (BrO and Cl) and OH(aq) concentrations in cloud droplets and aerosols. To reduce uncertainties in MBL sulfur chemistry, we should prioritize observations of reactive halogens and OH(aq).

Extension of a piezoelectric semiconductor fiber with consideration of electrical nonlinearity

We study the extension of a piezoelectric semiconductor fiber with consideration of the electrical nonlinearity due to the drift current which is the product of the unknown electric field and the unknown carrier concentration. The analysis is based on a one-dimensional model. A perturbation analysis is performed. The first-order solution is the linear solution known in the literature. The second- and third-order nonlinear solutions obtained in this paper are new. Numerical results show that when the axial load is small the linear and nonlinear solutions are essentially the same. As the axial load increases, the linear and nonlinear solutions gradually become more different. The nonlinear solution is valid for a larger range of load and establishes the range of applicability of the linear solution. It is also found that while the electromechanical fields predicted by the linear solution are either symmetric or antisymmetric about the middle of the rod, the fields described by the nonlinear solutions lose this symmetry and antisymmetry.

Analysis of a Free Boundary Problem Modeling the Growth of Spherically Symmetric Tumors with Angiogenesis

This paper is concerned with a free boundary problem modeling the growth of a spherically symmetric tumor with angiogenesis. The unknown nutrient concentration $\sigma =\sigma (r,t)$ occupies the unknown tumor region $r< R(t)$ and satisfies a nonlinear reaction diffusion equation, and the unknown tumor radius $R=R(t)$ satisfies a nonlinear integro-differential equation. Unlike existing literatures on this topic where Dirichlet boundary condition for $\sigma $ is imposed, in this paper the model uses the Robin boundary condition for $\sigma $ . We prove existence and uniqueness of a global in-time classical solution ( $\sigma (r,t),R(t)$ ) for arbitrary $c>0$ and establish asymptotic stability of the unique stationary solution ( $\sigma _{s}(r),R_{s}$ ) for sufficiently small $c$ , where $c$ is a positive constant reflecting the ratio between nutrient diffusion scale and the tumor cell-doubling scale.

Simulation Methods to Treat Some Factors Affecting Atomic Absorption measurements

Flame atomic absorption spectroscopy (FAAS) is used to quantitatively determine trace metals in the test samples. The purpose of the present study is to treat some of the factors affecting AAS measurements. Some of the factors are under the control of the operator while other factors depend on the used equipment. In the present work equipment was used with low detection limits and high sensitivity but still some factors can’t control. Using simulation methods to treat some of these measurements, obtain an estimate of the predicted concentration values for test samples. Two methods of simulation are investigated. The first simulation method is carried out by using line-of-best-fit through the experimental points using Excel programmed and using TREND function to estimate the unknown concentration directly from this calibration function. The second simulation method is based on the approximation programme which is built-in the concept of genetic programming (GP). This is carried out by the introduction of laboratory results of the known concentrations versus the absorption of known elements and finds the best curve of the approximate of each element. The results were rounded up to the laboratory results of most elements with low concentrations, the improvements of the methods were very satisfying and the results reached the imposed limits (A<0.05). Finally, a database was created for all results.

Mechanistic Insight of Platelet-Rich Plasma (PRP) in Mesenchymal and Vascular Progenitors

Background: Platelet-rich plasma (PRP) is broadly used for disease intervention, pain management and tissue repair without clear elucidation of its mechanisms of action. Clinically, 100% PRP is injected and yields unknown local concentrations when applied in cardiac infarcts, osteoarthritic joints, tendon injuries and numerous other conditions. Methods: Human PRP samples (26 donors) were obtained per conventional clinical methods. Human bone-marrow mesenchymal stem/progenitor cells (MSCs) were assayed for migration, proliferation and differentiation in response to different PRP concentrations. Human umbilical cord vascular endothelial cells (HUVEC) were assayed for endothelial tube formation. Cleaved Caspase 3 and TUNEL were assayed to evaluate apoptosis. Pro-inflammatory cytokines and FasL were assayed by ELISA. Osmotic pressure and pH were measured. All quantitative data were statistically treated. Findings: MSCs treated with 50% PRP detached into Caspase-3 and TUNEL debris, relative to scarce cell death upon exposure to ≤25% PRPs. Upon 50%-PRP treatment, MSCs produced ~180-fold more IL-1β and ~20-fold more FasL, relative to ≤25% PRPs. IL-6 and TNFα surged upon MSC exposure to 50% PRP. Osmotic pressure of 50% PRP was aberrantly high. Medium pH was neutral throughout the tested 7 days. Nonetheless, 1% to 25% PRPs induced dose-dependent MSC migration. Diluted PRPs induced endothelial tube formation directly or by PRP-treated MSC secretome. Diluted PRPs further elicited context-dependent biomineralization. BMP2, PDGF-BB, VEGF and pro-inflammatory cytokines including IL-1β, IL-6, TNFα had significantly lower concentration in bone marrow than in platelets. Interpretation: PRP's clinical use by aggregating growth factors is inevitably coupled with accumulation of excessive pro-inflammatory cytokines and apoptotic ligands. Cell death elicited by ≥50% PRPs suggests that PRP concentration and composition should be tailored for a given clinical indication. Robust biomineralization induced by PRPs may have implications in fracture healing, atherosclerosis and fibrodysplasia dissecans. Certain factors are preferentially stored in platelets, rather than bone marrow, likely owing to evolution and survival. Funding Statement: This work is funded by NIH grants R01AR065023, R01DE025643, R01DE023112, and R01DE026297. Declaration of Interests: We declare no competing interests. Dr. Jeremy Mao has co-founded biotechnology companies but without reference to PRP technologies in the past and presence. Ethics Approval Statement: IRB approval mentioned by authors in acquisition and use of human blood samples.

Dopamine Detection using Mercaptopropionic Acid and Cysteamine for Electrodes Surface Modification.

Gold electrodes are often not suitable for dopamine measurements as dopamine creates a non-conducting polymer layer on the surface of the electrodes, which leads to increased amount of electrode passivity with the gradual increase in voltammograms measurement. This work presents the impedance spectroscopy and cyclic-voltammetry comparative study for dopamine detection with two modifications for the surface of Au electrodes; cysteamine and mercaptopropionic acid for thermally bonded and ultrasonically welded microfluidic chips, respectively. The effects of optimized tubing selection, bonding techniques, and cleaning methods of the devices with KOH solution played crucial role for improvements in dopamine detection, which are observed in the results. Furthermore, comparison for the modification with unmodified chips, and finding the unknown concentration of dopamine solution using flow injection techniques, is also illustrated.