Design of a Non-Dispersive Infra-Red (NDIR) based CO2 sensor to detect the human respiratory CO2

Respiratory Carbon dioxide (CO2) contains substantial amount of information that can be used to diagnose and treat pulmonary diseases. Many devices have been developed for this purpose, such as capnography, vital monitor, peak flow meter, spirometer etc. There are many CO2 sensor are available in the market but among them NDIR based sensors are considered to be most inexpensive with its accuracy in terms of sensitivity and fast response time. There are commonly two types of technology available for detection; mainstream and sidestream. Mainstream technology is preferable than sidestream because sidestream is not applicable in intubated patients and at the same time it tends to give delay in detection due to longer transmission tube. Most of the NDIR CO2 sensor are being used for the environmental CO2 detection and there are very few mainstream NDIR based CO2 sensor are available in the market. These sensor have a vast number of advantages with some disadvantages as well; such as high response time, thermal noise, temperature increase and others. This project proposed the specification of the electrical circuit of the NDIR CO2 sensor combined with a gas chamber to detect human respiratory CO2. To determine the specification of the CO2 sensor circuit, the components value has been calculated and then the circuit design has been carried out by using Multisim Software. The overall CO2 sensor circuit has six circuit blocks named oscillator, driver circuit, preamplifier, voltage regulator, rectifier, LPF and each of the blocks were built and simulated in the Multisim software. After the simulation the circuit has been built on breadboard to test the output. An IR source from International Light Technologies (ILT) 4115-2A and pyroelectric photodetector L2100X2020 from laser component were used for this project as NDIR components. After the successful simulation from breadboard a gas acquisition cell has been designed to acquire the human CO2 gas. The design has been done by using Solid Works software and printed from a 3D printing machine. The material used for this chamber was ABS. After placing all the calculated components with the source and detector the output has been observed on the digital oscilloscope as a capnograph wave form showing the voltage range. These waveforms are being used in a capnometer determining respiratory diseases. The circuit shows a response time of 6 second with less noise and the waveform showed clear view of detected CO2 without any temperature increase

Dynamics of end-pulled polymer translocation through a nanopore

We consider the translocation dynamics of a polymer chain forced through a nanopore by an external force on its head monomer on the trans side. For a proper theoretical treatment we generalize the iso-flux tension propagation (IFTP) theory to include friction arising from the trans side subchain. The theory reveals a complicated scenario of multiple scaling regimes depending on the configurations of the cis and the trans side subchains. In the limit of high driving forces $f$ such that the trans subchain is strongly stretched, the theory is in excellent agreement with molecular dynamics simulations and allows an exact analytic solution for the scaling of the translocation time ${\tau}$ as a function of the chain length $N_0$ and $f$. In this regime the asymptotic scaling exponents for ${\tau} \sim N_0^{\alpha} f^{\beta}$ are $\alpha=2$, and $\beta =-1$. The theory reveals significant correction-to-scaling terms arising from the cis side subchain and pore friction, which lead to a very slow approach to $\alpha =2$ from below as a function of increasing $N_0$.Comment: 5 pages, 4 figure

Electrochemistry of Nanostructured Materials: Implementation in Electrocatalysis for Energy Conversion Applications

The study of electrochemical phenomena and electrocatalytic properties using chemical structures at nanoscale is a rapidly emerging area in electrochemical and material science. A notable achievement in the performance of functional materials has been the understanding of the electrochemical mechanisms and the development of advanced catalytic nanostructured materials. Consequently, efforts will continue to synthesise and explore novel nanoscale materials to meet the requirement of sustainable and renewable resources owing to climate change and the decreasing availability of fossil fuels. The present review explores in depth the current state of the nanoscale frontier in electrochemistry. It includes investigation of electrochemical processes of nanostructured materials, electroanalysis using nanostructured materials, fundamental aspects of electron transfer and mass transfer at nanoscale surface during catalysis. It will also provide an understanding of the activity and stability of electrocatalysts under critical experimental conditions. A brief discussion on the utilisation of nanostructured materials in energy domains such as fuel cells is presented at the end

Pulling a folded polymer through a nanopore

We investigate the translocation dynamics of a folded linear polymer which is pulled through a nanopore by an external force. To this end, we generalize the iso-flux tension propagation (IFTP) theory for end-pulled polymer translocation to include the case of two segments of the folded polymer traversing simultaneously trough the pore. Our theory is extensively benchmarked with corresponding Molecular Dynamics (MD) simulations. The translocation process for a folded polymer can be divided into two main stages. In the first stage, both branches are traversing the pore and their dynamics is coupled. If the branches are not of equal length, there is a second stage where translocation of the shorter branch has been completed. Using the assumption of equal monomer flux of both branches, we analytically derive the equations of motion for both branches and characterise the translocation dynamics in detail from the average waiting time and its scaling form. Moreover, MD simulations are used to study additional details of translocation dynamics such as the translocation time distribution and individual monomer velocities

Dynamics of end-pulled polymer translocation through a nanopore

© 2018 EPLA. We consider the translocation dynamics of a polymer chain forced through a nanopore by an external force on its head monomer on the trans side. For a proper theoretical treatment we generalize the iso-flux tension propagation (IFTP) theory to include friction arising from the trans side subchain. The theory reveals a complicated scenario of multiple scaling regimes depending on the configurations of the cis and the trans side subchains. In the limit of high driving forces f such that the trans subchain is strongly stretched, the theory is in excellent agreement with molecular dynamics simulations and allows an exact analytic solution for the scaling of the translocation time τ as a function of the chain length N 0 and f. In this regime the asymptotic scaling exponents for are , and . The theory reveals significant correction-to-scaling terms arising from the cis side subchain and pore friction, which lead to a very slow approach to from below as a function of increasing N 0

Facile synthesis of reduced graphene oxide-gold nanohybrid for potential use in industrial waste-water treatment

Here, we report a facile approach, by the photochemical reduction technique, for in situ synthesis of Au-reduced graphene oxide (Au-RGO) nanohybrids, which demonstrate excellent adsorption capacities and recyclability for a broad range of dyes. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) data confirm the successful synthesis of Au-RGO nanohybrids. The effect of several experimental parameters (temperature and pH) variation can effectively control the dye adsorption capability. Furthermore, kinetic adsorption data reveal that the adsorption process follows a pseudo second-order model. The negative value of Gibbs free energy (Delta G(0)) confirms spontaneity while the positive enthalpy (Delta H-0) indicates the endothermic nature of the adsorption process. Picosecond resolved fluorescence technique unravels the excited state dynamical processes of dye molecules adsorbed on the Au-RGO surface. Time resolved fluorescence quenching of Rh123 after adsorption on Au-RGO nanohybrids indicates efficient energy transfer from Rh123 to Au nanoparticles. A prototype device has been fabricated using Au-RGO nanohybrids on a syringe filter (pore size: 0.220 mu m) and the experimental data indicate efficient removal of dyes from waste water with high recyclability. The application of this nanohybrid may lead to the development of an efficient reusable adsorbent in portable water purification. GRAPHICS

Four-Dimensional Flow Magnetic Resonance Imaging and Applications in Cardiology

Blood flow through the heart and great vessels moves in three dimensions (3D) throughout time. However, the assessment of its 3D nature has been limited in the human body. Recent advances in magnetic resonance imaging (MRI) allow for the comprehensive visualization and quantification of in-vivo flow dynamics using four-dimensional (4D) flow MRI. In addition, this technique provides the opportunity to obtain advanced hemodynamic biomarkers such as vorticity, helicity, wall shear stress (WSS), pressure gradients, viscous energy loss (EL), and turbulent kinetic energy (TKE). This chapter will introduce 4D flow MRI which is currently used for blood flow visualization and advanced quantification of cardiac hemodynamic biomarkers. We will discuss its advantages relative to other in-vivo flow imaging techniques and describe its potential clinical applications in cardiology

Synthesis and Spectral Studies of CdTe–Dendrimer Conjugates

In order to couple high cellular uptake and target specificity of dendrimer molecule with excellent optical properties of semiconductor nanoparticles, the interaction of cysteine-capped CdTe quantum dots with dendrimer was investigated through spectroscopic techniques. NH2-terminated dendrimer molecule quenched the photoluminescence of CdTe quantum dots. The binding constants and binding capacity were calculated, and the nature of binding was found to be noncovalent. Significant decrease in luminescence intensity of CdTe quantum dots owing to noncovalent binding with dendrimer limits further utilization of these nanoassemblies. Hence, an attempt is made, for the first time, to synthesize stable, highly luminescent, covalently linked CdTe–Dendrimer conjugate in aqueous medium using glutaric dialdehyde (G) linker. Conjugate has been characterized through Fourier transform infrared spectroscopy and transmission electron microscopy. In this strategy, photoluminescence quantum efficiency of CdTe quantum dots with narrow emission bandwidths remained unaffected after formation of the conjugate

High monocytic MDSC signature predicts multi-drug resistance and cancer relapse in non-Hodgkin lymphoma patients treated with R-CHOP

IntroductionNon-Hodgkin Lymphoma (NHL) is a heterogeneous lymphoproliferative malignancy with B cell origin. Combinatorial treatment of rituximab, cyclophsphamide, hydroxydaunorubicin, oncovin, prednisone (R-CHOP) is the standard treatment regimen for NHL, yielding a complete remission (CR) rate of 40-50%. Unfortunately, considerable patients undergo relapse after CR or initial treatment, resulting in poor clinical implications. Patient’s response to chemotherapy varies widely from static disease to cancer recurrence and later is primarily associated with the development of multi-drug resistance (MDR). The immunosuppressive cells within the tumor microenvironment (TME) have become a crucial target for improving the therapy efficacy. However, a better understanding of their involvement is needed for distinctive response of NHL patients after receiving chemotherapy to design more effective front-line treatment algorithms based on reliable predictive biomarkers.MethodsPeripheral blood from 61 CD20+ NHL patients before and after chemotherapy was utilized for immunophenotyping by flow-cytometry at different phases of treatment. In-vivo and in-vitro doxorubicin (Dox) resistance models were developed with murine Dalton’s lymphoma and Jurkat/Raji cell-lines respectively and impact of responsible immune cells on generation of drug resistance was studied by RT-PCR, flow-cytometry and colorimetric assays. Gene silencing, ChIP and western blot were performed to explore the involved signaling pathways.ResultsWe observed a strong positive correlation between elevated level of CD33+CD11b+CD14+CD15- monocytic MDSCs (M-MDSC) and MDR in NHL relapse cohorts. We executed the role of M-MDSCs in fostering drug resistance phenomenon in doxorubicin-resistant cancer cells in both in-vitro, in-vivo models. Moreover, in-vitro supplementation of MDSCs in murine and human lymphoma culture augments early expression of MDR phenotypes than culture without MDSCs, correlated well with in-vitro drug efflux and tumor progression. We found that MDSC secreted cytokines IL-6, IL-10, IL-1β are the dominant factors elevating MDR expression in cancer cells, neutralization of MDSC secreted IL-6, IL-10, IL-1β reversed the MDR trait. Moreover, we identified MDSC secreted IL-6/IL-10/IL-1β induced STAT1/STAT3/NF-κβ signaling axis as a targeted cascade to promote early drug resistance in cancer cells.ConclusionOur data suggests that screening patients for high titre of M-MDSCs might be considered as a new potential biomarker and treatment modality in overcoming chemo-resistance in NHL patients