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1.
IEEE Trans Biomed Eng ; 71(6): 1864-1878, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38300773

ABSTRACT

Time-resolved fluorescence imaging techniques, like confocal fluorescence lifetime imaging microscopy, are powerful photonic instrumentation tools of modern science with diverse applications, including: biology, medicine, and chemistry. However, complexities of the systems, both at specimen and device levels, cause difficulties in quantifying soft biomarkers. To address the problems, we first aim to understand and model the underlying photophysics of fluorescence decay curves. For this purpose, we provide a set of mathematical functions, called "life models", fittable with the real temporal recordings of histogram of photon counts. For each model, an equivalent electrical circuit, called a "life circuit", is derived for explaining the whole process. In confocal endomicroscopy, the components of excitation laser, specimen, and fluorescence-emission signal as the histogram of photon counts are modelled by a power source, network of resistor-inductor-capacitor circuitry, and multimetre, respectively. We then design a novel pixel-level temporal classification algorithm, called a "fit-flexible approach", where qualities of "intensity", "fall-time", and "life profile" are identified for each point. A model selection mechanism is used at each pixel to flexibly choose the best representative life model based on a proposed Misfit-percent metric. A two-dimensional arrangement of the quantified information detects some kind of structural information. This approach showed a potential of separating microbeads from lung tissue, distinguishing the tri-sensing from conventional methods. We alleviated by 7% the error of the Misfit-percent for recovering the histograms on real samples than the best state-of-the-art competitor. Codes are available online.


Subject(s)
Algorithms , Microscopy, Confocal/methods , Microscopy, Confocal/instrumentation , Optical Imaging/methods , Optical Imaging/instrumentation , Microscopy, Fluorescence/methods , Microscopy, Fluorescence/instrumentation , Image Processing, Computer-Assisted/methods , Equipment Design , Humans
2.
Front Chem ; 11: 1040873, 2023.
Article in English | MEDLINE | ID: mdl-37228864

ABSTRACT

A plug-and-play sandwich assay platform for the aptamer-based detection of molecular targets using linear dichroism (LD) spectroscopy as a read-out method has been demonstrated. A 21-mer DNA strand comprising the plug-and-play linker was bioconjugated onto the backbone of the filamentous bacteriophage M13, which gives a strong LD signal due to its ready alignment in linear flow. Extended DNA strands containing aptamer sequences that bind the protein thrombin, TBA and HD22, were then bound to the plug-and-play linker strand via complementary base pairing to generate aptamer-functionalised M13 bacteriophages. The secondary structure of the extended aptameric sequences required to bind to thrombin was checked using circular dichroism spectroscopy, with the binding confirmed using fluorescence anisotropy measurements. LD studies revealed that this sandwich sensor design is very effective at detecting thrombin down to pM levels, indicating the potential of this plug-and-play assay system as a new label-free homogenous detection system based on aptamer recognition.

3.
EURASIP J Wirel Commun Netw ; 2021(1): 33, 2021.
Article in English | MEDLINE | ID: mdl-33613666

ABSTRACT

The body area network is now the most challenging and most popular network for study and research. Communication about the body has undoubtedly taken its place due to a wide variety of applications in industry, health care, and everyday life in wireless network technologies. The body area network requires such smart antennas that can provide the best benefits and reduce interference with the same channel. The discovery of this type of antenna design is at the initiative of this research. In this work, to get a good variety, the emphasis is on examining different techniques. The ultra-wide band is designed, simulated, and manufactured because the ultra-wide band offers better performance compared to narrowband antennas. To analyze the specific absorption rate, we designed a multilayer model of human head and hand in the high-frequency structure simulator. In the final stage, we simulated our antennas designed with the head and hand model to calculate the results of the specific absorption rate. The analysis of the specific absorption rate for the head and hand was calculated by placing the antennas on the designed model.

4.
RSC Chem Biol ; 1(5): 449-454, 2020 Dec 01.
Article in English | MEDLINE | ID: mdl-34458772

ABSTRACT

Nucleic acid detection is an important part of our bio-detection arsenal, with the COVID-19 pandemic clearly demonstrating the importance to healthcare of rapid and efficient detection of specific pathogenic sequences. As part of the drive to establish new DNA detection methodologies and signal read-outs, here we show how linear dichroism (LD) spectroscopy can be used to produce a rapid and modular detection system for detecting quantities of DNA from both bacterial and viral pathogens. The LD sensing method exploits changes in fluid alignment of bionanoparticles (bacteriophage M13) engineered with DNA stands covalently attached to their surfaces, with the read-out signal induced by the formation of complementary duplexes between DNA targets and two M13 bionanoparticles. This new sandwich assay can detect pathogenic material down to picomolar levels in under 1 minute without amplification, as demonstrated by the successful sensing of DNA sequences from a plant virus (Potato virus Y) and an ampicillin resistance gene, ampR.

5.
Chem Commun (Camb) ; 55(39): 5627-5630, 2019 May 09.
Article in English | MEDLINE | ID: mdl-31025680

ABSTRACT

The reversible photocontrol of an enzyme governing blood coagulation is demonstrated. The thrombin binding aptamer (TBA), was rendered photochromic by modification with two anthracene groups. Light-triggered anthracene photodimerisation distorts its structure, inhibiting binding of the enzyme thrombin, which in turn triggers catalysis and the resulting clotting process.


Subject(s)
Aptamers, Nucleotide/metabolism , G-Quadruplexes , Thrombin/metabolism , Ultraviolet Rays , Anthracenes/chemistry , Aptamers, Nucleotide/chemistry , Biocatalysis , Blood Coagulation , Circular Dichroism , Dimerization , Humans , Protein Binding , Temperature , Thrombin/chemistry
6.
Perioper Med (Lond) ; 5: 10, 2016.
Article in English | MEDLINE | ID: mdl-27222707

ABSTRACT

BACKGROUND: Postoperative pulmonary complications (PPC) are an under-reported but major cause of perioperative morbidity and mortality. The aim of this prospective, contemporary, multicentre cohort study of unselected patients undergoing major elective abdominal surgery was to determine the incidence and effects of PPC. METHODS: Data on all major elective abdominal operations performed over a 2-week period in December 2014 were collected in six hospitals. The primary outcome measure of PPC at 7 days was used. Univariate and multivariate analyses were performed to investigate how different factors were associated with PPC and the effects of such complications. RESULTS: Two hundred sixty-eight major elective abdominal operations were performed, and the internal validation showed that the data set was 99 % accurate. Thirty-two (11.9 %) PPC were reported at 7 days. PPC was more common in patients with a history of chronic obstructive pulmonary disease compared to those with no history (26.7 vs. 10.2 %, p < 0.001). PPC was not associated with other patient factors (e.g. age, gender, body mass index or other comorbidities), type/method of operation or postoperative analgesia. The risk of PPC appeared to increase with every additional minute of operating time independent of other factors (odds ratio 1.01 (95 % confidence intervals 1.00-1.02), p = 0.007). PPC significantly increase the length of hospital stay (10 vs. 3 days). Attendance to the emergency department within 30 days (27.3 vs. 10.6 %), 30-day readmission (21.7 vs. 9.9 %) and 30-day mortality (12.5 vs. 0.0 %) was higher in those with PPC. CONCLUSIONS: PPC are common and have profound effects on outcomes. Strategies need to be considered to reduce PPC.

7.
J Clin Diagn Res ; 10(1): EC04-6, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26894070

ABSTRACT

INTRODUCTION: Thrombotic disorders have been found to be associated with recurrent abortions. Several risk factors have been identified. APTT reflects the common pathway and intrinsic pathway of coagulation cascade and hence is a good marker for thrombotic work. Elevated factor VIII: C has also been identified as risk factor for recurrent miscarriage. This study aims at identifying association of elevated factor VIII levels, shortened APTT and recurrent abortions in Indian population as little has been studied about this and the literature available is also based on studies done in European population. This study also aims to find whether shortened APTT can be an independent risk as well. MATERIALS AND METHODS: Women referred to the obstetrics department with a history of early recurrent early pregnancy loss (at least three pregnancy losses before 13 weeks of gestation) were included in this study. Exclusion criteria were elevated CRP levels, positive antiphospholipid antibodies, endocrine, immunological or anatomical cause of embryo demise. A total of 68 cases of recurrent abortion were included in this study, 68 normal pregnant females (<15 weeks of gestation) were also included as controls with no history of abortion. The age group of the cases as well as control was 20-45 years. Activated partial thromboplastin time and factor VIII assay (one stage APTT based) were done on the blood samples. RESULTS: Increased factor VIII levels were seen in 25 cases (36.4%); 19 cases showed shortened APTT (27.3%); 12 cases showed both increased factor VIII levels as well as shortened APTT (18%). All risk factors were negative in 36 cases (52.9%). None of the controls showed elevated factor VIII levels or shortened APTT. The mean APTT values of the control subjects was 31.01 and cases were 27.01 (p=0.001). The mean factor VIII levels of case were 152.85% and control 144.953% (p=0.012). CONCLUSION: There was significant association between recurrent abortions and elevated factor VIII :c levels and shortened APTT. Shortened APTT was also identified as an independent risk factor.

9.
Proc Natl Acad Sci U S A ; 109(46): E3186-95, 2012 Nov 13.
Article in English | MEDLINE | ID: mdl-23100531

ABSTRACT

Although macrophages are widely recognized to have a profibrotic role in inflammation, we have used a highly tractable CCl(4)-induced model of reversible hepatic fibrosis to identify and characterize the macrophage phenotype responsible for tissue remodeling: the hitherto elusive restorative macrophage. This CD11B(hi) F4/80(int) Ly-6C(lo) macrophage subset was most abundant in livers during maximal fibrosis resolution and represented the principle matrix metalloproteinase (MMP) -expressing subset. Depletion of this population in CD11B promoter-diphtheria toxin receptor (CD11B-DTR) transgenic mice caused a failure of scar remodeling. Adoptive transfer and in situ labeling experiments showed that these restorative macrophages derive from recruited Ly-6C(hi) monocytes, a common origin with profibrotic Ly-6C(hi) macrophages, indicative of a phenotypic switch in vivo conferring proresolution properties. Microarray profiling of the Ly-6C(lo) subset, compared with Ly-6C(hi) macrophages, showed a phenotype outside the M1/M2 classification, with increased expression of MMPs, growth factors, and phagocytosis-related genes, including Mmp9, Mmp12, insulin-like growth factor 1 (Igf1), and Glycoprotein (transmembrane) nmb (Gpnmb). Confocal microscopy confirmed the postphagocytic nature of restorative macrophages. Furthermore, the restorative macrophage phenotype was recapitulated in vitro by the phagocytosis of cellular debris with associated activation of the ERK signaling cascade. Critically, induced phagocytic behavior in vivo, through administration of liposomes, increased restorative macrophage number and accelerated fibrosis resolution, offering a therapeutic strategy to this orphan pathological process.


Subject(s)
Antigens, Ly/immunology , Carbon Tetrachloride Poisoning/immunology , Gene Expression Regulation/immunology , Liver Cirrhosis/immunology , Macrophages/immunology , Monocytes/immunology , Animals , Antigens, Ly/genetics , CD11b Antigen/genetics , CD11b Antigen/immunology , Carbon Tetrachloride/toxicity , Carbon Tetrachloride Poisoning/genetics , Carbon Tetrachloride Poisoning/pathology , Gene Expression Regulation/drug effects , Gene Expression Regulation/genetics , Insulin-Like Growth Factor I/genetics , Insulin-Like Growth Factor I/immunology , Liver Cirrhosis/chemically induced , Liver Cirrhosis/genetics , Liver Cirrhosis/pathology , MAP Kinase Signaling System/drug effects , MAP Kinase Signaling System/genetics , MAP Kinase Signaling System/immunology , Macrophages/pathology , Matrix Metalloproteinase 12/genetics , Matrix Metalloproteinase 12/immunology , Matrix Metalloproteinase 9/genetics , Matrix Metalloproteinase 9/immunology , Mice , Mice, Transgenic , Monocytes/pathology
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