Sensitive Imaging Research Articles

A two-layer circuit cascade-based DNA machine for highly sensitive miRNA imaging in living cells.

Sensitive detection of microRNA (miRNA), one of the most promising biomarkers, plays crucial roles in cancer diagnosis. However, the low expression level of miRNA makes it extremely urgent to develop ultrasensitive and highly selective strategies for quantification of miRNA. Herein, a DNA machine is rationally constructed for amplified detection and imaging of low-abundance miRNA in living cells based on the toehold-mediated strand displacement reaction (TMSDR). The isothermal and enzyme-free DNA machine with low background leakage is fabricated by integrating two DNA circuits into a cascade system, in which the output of one circuit serves as the input of the other one. Once the DNA machine is transfected into breast cancer cells, the overexpressed miRNA-203 initiates the first-layer circuit through TMSDR, leading to the concentration variation of fuel strands, which further influences the assembly of hairpin DNA in the second-layer circuit and the occurrence of fluorescence resonance energy transfer (FRET) for fluorescence imaging. Benefiting from the cascade of the two-layer amplification reaction, the proposed DNA machine acquires a detection limit down to 4 fM for quantification of miR-203 and a 10 000-fold improvement in amplification efficiency over the single circuit. Therefore, the two-layer circuit cascade-based DNA machine provides an effective platform for amplified analysis of low-abundance miRNA with high sensitivity, which holds great promise in biomedical and clinical research.

Significant chemiluminescence enhancement by tannic acid functionalised plasmonic silver nanoparticles

Tannic acid functionalised Ag nanospheres achieved a 175-fold increase in luminol chemiluminescence. This study focused on nanostructure optimisation, spacer design, and the difference between plasmonic and catalytic effects, leading to advancements in sensitive detection and imaging.

Small Animal Multisubject PET/CT Workflow.

Positron emission tomography (PET) is a highly sensitive molecular imaging technique that uses radioactive tracers to map molecular and metabolic processes in living animals. PET can be performed as a stand-alone modality but is often combined with CT to provide for objective anatomical localization of PET signals in a multimodality approach. In order to outline the general approach to evaluating four mice simultaneously by dynamic PET imaging, the use of the aldehyde-targeted radiotracer [18F]NA3BF3 in mouse models of hepatotoxicity will be described. Indeed the production of aldehydes is upregulated in a wide range of disease and injury, making them a suitable biomarker for PET imaging of numerous pathologies.

X-ray activated near-infrared persistent luminescence nanoparticles for trimodality in vivo imaging.

As promising luminescence nanoparticles, near-infrared (NIR) persistent luminescence nanoparticles (PLNPs) have received extensive attention in the field of high-sensitivity bioimaging in recent years. However, NIR PLNPs face problems such as short excitation wavelengths and single imaging modes, which limit their applications in in vivo reactivated imaging and multimodal imaging. Here, we report for the first time novel Gd2GaTaO7:Cr3+,Yb3+ (GGTO) NIR PLNPs that integrate X-ray activated NIR persistent luminescence (PersL), high X-ray attenuation and excellent magnetic properties into a single nanoparticle (NP). In this case, Cr3+ is used as the luminescence center. The co-doped Yb3+ and coating effectively enhance the X-ray activated NIR PersL. At the same time, the presence of the high-Z element Ta also makes the GGTO NPs exhibit high X-ray attenuation performance, which can be used as a CT contrast agent to achieve in vivo CT imaging. In addition, since the matrix contains a large amount of Gd, the GGTO NPs show remarkable magnetic properties, which can realize in vivo MR imaging. GGTO NPs combine the trimodal benefits of X-ray reactivated PersL, CT and MR imaging and are suitable for single or combined applications that require high sensitivity and spatial resolution imaging.

Design strategies and biological applications of β-galactosidase fluorescent sensor in ovarian cancer research and beyond.

Beta-galactosidase (β-galactosidase), a lysosomal hydrolytic enzyme, plays a critical role in the catalytic hydrolysis of glycosidic bonds, leading to the conversion of lactose into galactose. This hydrolytic enzyme is used as a biomarker in various applications, including enzyme-linked immunosorbent assays (ELISAs), gene expression studies, tuberculosis classification, and in situ hybridization. β-Galactosidase abnormalities are linked to various diseases, such as ganglioside deposition, primary ovarian cancer, and cell senescence. Thus, effective detection of β-galactosidase activity may aid disease diagnoses and treatment. Activatable optical probes with high sensitivity, specificity, and spatiotemporal resolution imaging capabilities have become powerful tools for visualization and real time tracking in vivo in the past decade. This manuscript reviews the sensing mechanism, molecular design strategies, and advances of fluorescence probes in the biological application of β-galactosidase, particularly in the field of ovarian cancer research. Current challenges in tracking β-galactosidase and future directions are also discussed.

Magnetic Resonance Imaging of Spinal Bone Marrow Signal Alterations with Emphasis on Pattern Recognition: A Case Series

Magnetic Resonance Imaging (MRI) is the most sensitive imaging modality available to detect bone marrow oedema. Different pathological conditions of the spine exhibit distinct and specific bone marrow oedema patterns or signal characteristics. Understanding these patterns for various types of bone marrow oedema in the spine, such as degenerative and pathological conditions, helps to prevent unnecessary investigations and further work-up. In this article, authors detail the specific imaging characteristics of benign versus malignant or pathological fractures, tuberculosis and non tubercular infections of the spine, as well as the imaging appearance of multiple myeloma, among others. Therefore, this article mainly emphasises the approach to bone marrow oedema detected in the spine, aiding in reaching the correct diagnosis and guiding proper management.

Combined Use of Magnetization Transfer Ratio and T2-Mapping to Evaluate Extraocular Muscle Pathophysiology in Myasthenia Gravis with Ophthalmoparesis.

Background Myasthenia gravis (MG) is an autoimmune neuromuscular disorder that most frequently affects the extraocular muscles (EOMs), which causes symptoms such as ptosis and restricted eye movement. The EOMs in MG patients are representative of autoimmune inflammatory changes in muscle tissue. Currently, there is no reliable, and sensitive imaging technique for monitoring EOM changes to assist in the evaluation of underlying pathological changes. Methods This study included MG patients treated between March and November 2022 at the First Affiliated Hospital of Sun Yat-sen University. Healthy controls (matched by age and sex) were included. Participants underwent 3.0 T MRI with magnetization transfer imaging (MTI) and T2-mapping to measure the magnetization transfer ratio (MTR) and T2-mapping values in the superior, inferior, medial, and lateral rectus muscles. Comparisons were made between MG patients and healthy controls, and between MG subgroups with and without ophthalmoparesis. Results The MTR and T2-mapping values successfully reflected EOM fibrosis and inflammatory edema in MG patients. MG patients showed significantly higher MTR and T2-mapping values in the EOMs compared with healthy controls. MG patients with ophthalmoparesis exhibited a lower MTR but higher T2-mapping value compared with those without ophthalmoparesis. Combined MTR and T2-mapping values effectively distinguished between MG patients and healthy controls, and between different severities of EOM involvement, with a superior diagnostic accuracy compared with each parameter alone. Conclusion The combination of MTI and T2-mapping MRI techniques can provide key insight into the pathological changes in EOMs in MG patients. This approach enhances early diagnosis and treatment planning, and therefore may improve clinical outcomes.

An activatable fluorescent-photoacoustic dual-modal probe for highly sensitive imaging of nitroxyl in vivo.

Nitroxyl (HNO) plays a vital role in various biological functions and pharmacological activities, so the development of an excellent near-infrared fluorescent (NIRF) and photoacoustic (PA) dual-modality probe is crucial for understanding HNO-related physiological and pathological progression. Herein, we proposed and synthesized a novel NIRF/PA dual probe (QL-HNO) by substituting an indole with quinolinium in hemicyanine for the sensitive detection of exogenous and endogenous HNO in vivo. The designed probe showed the highest sensitivity in NIRF mode and a desirable PA signal-to-noise ratio for HNO detection in vitro and was further applied for NIRF/PA dual-modal imaging of HNO with high contrast in living cells and tumor-bearing animals. Based on the excellent performance of QL-HNO, we believe that this study provides a promising molecular tool for further understanding of HNO-related physiological and pathological progression.

Protecting Sensitive Images with Improved 6-D Logistic Chaotic Image Steganography

In the digital age, strong methods for safeguarding sensitive data are essential. Image steganography is a practical technique for data protection that hides information inside seemingly authentic images. The proposed method increases security by using chaotic based image encryption and decryption. Encryption approaches based on chaotic logistic theory present an abundance of attractive and novel opportunities for developing secure image encryption methods. Nevertheless, these maps are frequently used for specific, unpredictable starting parameters. This problem is addressed by the research's Tabu search optimisation method. This method optimises chaotic map initial settings using a fitness function with numerous objectives. For image encryption, the most efficient methods are used to produce confidential keys. The input picture undergoes horizontal and vertical diffusion and permutation during encryption. These operations further scramble the image data, making it even more difficult to detect the hidden information. The primary goal is to develop a safe method for encrypting both color and grayscale images. Two common grayscale and color images that are accessible to the public were used to test the suggested strategy. compare our method with key existing works, specifically on the basis of Number of Pixels Change Rate (NPCR), Unified Average Changing Intensity (UACI), Peak Signal-to-Noise Ratio (PSNR) and speed, respectively, our approach improves upon these studies. Our results demonstrate that 7.9981, 99.8245, 35.6507, and 78.871 are the greatest values of entropy, NPCR, UACI, and PSNR, respectively. Whereas the respective speeds of encryption and decryption increase to 0.8433 and 1.4387 seconds. This innovative approach presents a powerful tool for applications requiring secure image steganography

An acid-responsive DNA hydrogel-mediated cascaded enzymatic nucleic acid amplification system for the sensitive imaging of alkaline phosphatase in living cells.

Alkaline phosphatase (ALP) is a class of hydrolase that catalyzes the dephosphorylation of phosphorylated species in biological tissues, playing an important role in many physiological and pathological processes. Sensitive imaging of ALP activity in living cells is contributory to the research on these processes. Herein, we propose an acid-responsive DNA hydrogel to deliver a cascaded enzymatic nucleic acid amplification system into cells for the sensitive imaging of intracellular ALP activity. The DNA hydrogel is formed by two kinds of Y-shaped DNA monomers and acid-responsive cytosine-rich linkers. The amplification system contained Bst DNA polymerase (Bst DP), Nt.BbvCI endonuclease, a Recognition Probe (RP, containing a DNAzyme sequence, a Nt.BbvCI recognition sequence, and a phosphate group at the 3'-end), and a Signal Probe (SP, containing a cleavage site for DNAzyme, Cy3 and BHQ2 at the two ends). The amplification system was trapped into the DNA hydrogel and taken up by cells, and the cytosine-rich linkers folded into a quadruplex i-motif in the acidic lysosomes, leading to the collapse of the hydrogel and releasing the amplification system. The phosphate groups on RPs were recognized and removed by the target ALP, triggering a polymerization-nicking cycle to produce large numbers of DNAzyme sequences, which then cleaved multiple SPs, restoring Cy3 fluorescence to indicate the ALP activity. This strategy achieved sensitive imaging of ALP in living HeLa, MCF-7, and NCM460 cells, and realized the sensitive detection of ALP in vitro with a detection limit of 2.0 × 10-5 U mL-1, providing a potential tool for the research of ALP-related physiological and pathological processes.

Role of 2-(fluorine-18) Fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography in Initial Staging and Bone Marrow Involvement Prediction in Patients with Newly Diagnosed Lymphoma in Correlation with Bone Marrow Study.

Lymphoma is a common malignant proliferative disease in which bone marrow infiltration will upstage the disease and thus affect prognosis of the disease. As of now bone marrow biopsy is considered as a reference standard to find out bone marrow involvement in lymphoma. Performing an invasive and painful intervention in all newly diagnosed lymphoma patients is controversial. PET-CT is a non-invasive technique that gives functional information about the cells using the glucose metabolism. It can detect early bone marrow and extra medullary organ involvement which can lead to restaging of the disease. These advantages make PET-CT a valuable adjunct in diagnosis of lymphoma. Our study aims to evaluate the usefulness of 18 F-FDG PET-CT, a non-invasive, semi quantitative whole body imaging technique for detection of early bone marrow and extra medullary organ involvement in lymphoma patients which in turn can obviate the need for bone marrow study (BMS). The primary objective of study is to categorise FDG uptake in bone marrow as diffuse /unifocal /multifocal / no uptake and to correlate pattern of FDG uptake to bone marrow study. Our study also assesses the role of FDG PET/CT in staging of lymphoma. Thirty patients with newly diagnosed lymphoma in the age group 18 to 75 years of both sexes within 3 months of diagnosis and who have not been started on any treatment was included in the study. Marrow uptake on FDG PET/CT has been categorized as diffuse, unifocal, multifocal and no uptake. Agreement between bone marrow study and FDG PET/CT has been assessed by reliability analysis using Cohen's kappa. Sensitivity, specificity, PPV, NPV of PET/CT in detecting marrow involvement have been calculated. The sensitivity, specificity, PPV, NPV and accuracy of 18 F-FDG PET-CT in detecting marrow involvement of lymphoma cases are 86.6%, 77.7%, 68.4%, 91.3% and 80.9% respectively. 18 F-FDG PET-CT detected bone marrow involvement in 86.6% (13 out of 15 total positive cases) cases of lymphoma which included both HL and NHL. Reliability analysis using Cohen's kappa is used to test the agreement between bone marrow study and 18F-FDG PET/CT. k value of 0.6 was obtained which showed a moderate agreement between bone marrow study and 18F-FDG PET/CT in marrow assessment. 18F-FDG PET/CT is a highly sensitive imaging modality which can pick up extra-nodal organ and BMI in patients with lymphoma and can upstage the disease and alter treatment strategies. PET-CT cannot completely replace the bone marrow study. However, being an invasive painful procedure, BMB can be avoided in cases with unifocal or multifocal marrow involvement on PET-CT.

Using Fuzzy Mathematical Model in the Differential Diagnosis of Pancreatic Lesions Using Ultrasonography and Echographic Texture Analysis.

Malignant tumors of the pancreas are the fourth leading cause of cancer-related deaths. This is mainly because they are often diagnosed at a late stage. One of the challenges in diagnosing focal lesions in the pancreas is the difficulty in distinguishing them from other conditions due to the unique location and anatomy of the organ, as well as the similarity in their ultrasound characteristics. One of the most sensitive imaging modalities of the pancreas is endoscopic ultrasonography. However, clinicians recognize that EUS is a difficult and highly operator-dependent method, while its results are highly dependent on the experience of the investigator. Hybrid technologies based on artificial intelligence methods can improve the accuracy and objectify the results of endosonographic diagnostics. Endoscopic ultrasonography was performed on 272 patients with focal lesions of the pancreatobiliary zone, who had been treated in the surgical section of the Kursk Regional Clinical Hospital in 2014-2023. The study utilized an Olympus EVIS EXERA II video information endoscopic system, along with an EU-ME1 ultrasound unit equipped with GF UM160 and GF UC140P-AL5 echo endoscopes. Out of the focal formations in the pancreatobiliary zone, pancreatic cancer was detected in 109 patients, accounting for 40.1% of the cases. Additionally, 40 patients (14.7%) were diagnosed with local forms of chronic pancreatitis. The reference sonograms displayed distinguishable focal pancreatic pathologies, leading to the development of hybrid fuzzy mathematical decision-making rules at the South-West State University in Kursk, Russian Federation. This research resulted in the creation of a fuzzy hybrid model for the differential diagnosis of chronic focal pancreatitis and pancreatic cancer. Endoscopic ultrasonography, combined with hybrid fuzzy logic methodology, has made it possible to create a model for differentiating between chronic focal pancreatitis and pancreatic ductal adenocarcinoma. Statistical testing on control samples has shown that the diagnostic model, based on reference endosonograms of the echographic texture of pancreatic focal pathology, has a confidence level of 0.6 for the desired diagnosis. By incorporating additional information about the contours of focal formations obtained through endosonography, the reliability of the diagnosis can be increased to 0.9. This level of reliability is considered acceptable in clinical practice and allows for the use of the developed model, even with data that is not well-structured.

Carboxylesterase-activated near-infrared fluorescence probe for highly sensitive imaging of liver tumors.

Carboxylesterases (CESs) are critical for metabolizing ester-containing biomolecules and are specifically important in liver metabolic disorders. The modulation of CESs is also an important issue in pharmacology and clinical applications. Herein, we present a near-infrared (NIR) CES fluorescent probe (NCES) based on the protection-deprotection of the hydroxyl group for monitoring CES levels in living systems. The NCES probe has good selectivity and sensitivity for CESs with a limit of detection (LOD) of 5.24 mU mL-1, which allows for tracing the fluctuation of cellular CES after treatment with anticancer drugs and under inflammation and apoptosis states. Furthermore, NCES can be successfully applied for guiding liver cancer surgery with high-contrast in vivo imaging and detecting clinical serum samples from liver cancer patients. This work showed that the NCES probe has great potential in drug development, imaging applications for medical diagnosis, and early-stage detection for clinical liver diseases.

A DNA nanowire based-DNAzyme walker for amplified imaging of microRNA in tumor cells.

Sensitive imaging of microRNAs (miRNAs) in tumor cells holds great significance in the domains of pathology, drug development, and personalized diagnosis and treatment. DNA nanostructures possess excellent biostability and programmability and are suitable as carriers for intracellular imaging probes. With its highly controllable motion mechanism and remarkable target recognition specificity, the DNA walker is an ideal tool for living cell imaging. Here, we report a DNA nanowire based-DNAzyme Walker (D-Walker), which loads the DNAzyme based-molecular beacon (D-MB) onto DNA nanowires (NWs) functionalized with aptamers. The experimental results demonstrated that the intracellular target miRNA can specifically activate the pre-locked DNAzyme through a strand displacement reaction, thereby triggering the cleavage of its substrate molecular beacon (MB) and subsequent fluorescence emission. NWs decorated with aptamers can effectively prevent the degradation of the D-Walker by nuclease, and can enter target cells without any transfection reagents, which enhances the stability and reliability of cell imaging. Furthermore, the D-Walker exhibited a remarkable sensitivity with a limit of detection (LOD) of 61 pM and was capable of distinguishing miRNA-21 from other closely related family members. This study provides a novel strategy for intracellular miRNA imaging, offering a promising tool for cancer diagnosis and treatment.

Enhancing image security and privacy with hybrid double random phase encoding, lorenz maps, and compressed sensing

The resilient and secure image encryption method presented in this research combines the benefits of Lorenz maps and double random phase encoding (DRPE) with compressed sensing. The suggested method attempts to maximize the use of storage resources while maintaining the security and integrity of sensitive image data during transmission and storage. Utilizing the energy compaction characteristics of the original image, compressed sensing with discrete cosine transform (DCT) is used in the encryption process to effectively represent and transmit the encrypted data. Lorenz maps are also used to create double random phase masks, adding high unpredictability and key sensitivity to strengthen the encryption scheme’s security. Utilizing a variety of performance indicators, including the PSNR, NPCR, MSE, and SSIM, experimental investigations demonstrate the usefulness of the suggested strategy.

Survey Study Image Cryptography System

Encryption is vital for data security, converting information into an unreadable format to ensure privacy in online communication and sensitive sectors. Advanced encryption balances innovation and security in user-friendly applications. Image encryption employs techniques to protect image data from unauthorized access during transmission or storage, particularly crucial for safeguarding sensitive images in various applications. The goal is to prevent unauthorized access and ensure the safety of associated information. In this paper, I present a study on previous research related to my investigation, which focuses on encryption in general and image encryption in particular. The paper also discusses the methods used, particularly those closely related to my work, involving either SHA-256, MD5, or a combination of both. The review will look at the many strategies and techniques employed, as well as how precisely the task was completed by applying a set of parameters in comparison to earlier studies.

MRI for axial SpA: Diagnosis, disease activity assessment, and recent advances.

Magnetic resonance imaging (MRI) is a sensitive imaging modality to detect early inflammatory changes in axial spondyloarthritis (SpA). Over a decade has passed since the inclusion of MRI assessment in the 2009 Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axial SpA. Evidence and clinical experience of MRI in axial SpA have accumulated rapidly since. This has led to a better understanding of the clinical utility of MRI in early diagnosis, disease activity assessment, and monitoring of treatment response in axial SpA. Furthermore, technological advancements have paved the way for the development of novel MRI sequences for the quantification of inflammation and image optimization. The field of artificial intelligence has also been explored to aid medical imaging interpretation, including MRI in axial SpA. This review serves to provide an update on the latest understanding of the evolving roles of MRI in axial SpA.

A NIR-II fluorescence probe for tracking oxidative stress in plants induced by metal contaminants.

The contamination of some metal ions in soil and water can cause oxidative stress to plants through several mechanisms such as generation of reactive oxygen species, which impair growth, development and productivity of crops. The oxidative stress in plants results in elevation in NO levels which can be adopted as a marker for tracking the stress. Herein we report a new approach for tracking oxidative stress induced by metal ions in plants by using a NIR-II fluorescence probe (Cy-TPE-NH). As for this NIR-II probe, heptamethine cyanine serves as the fluorophore backbone, and two triphenylethenes (TPEs) are attached on its each terminal respectively; moreover, an electron-donating benzylamine is linked to its meso-position as the responsive element for NO detection, and three tri(ethylene glycol) chains are introduced to enhance the hydrophilicity of the cyanine to ensure its applicability in the aqueous environment of plants. The N-nitrosation of the benzylamine caused by the presence of NO produces an electron-withdrawing benzyl-N-nitro group, thereby changing the electronic state of the probe and resulting in strong fluorescence emission in the near infrared II region. When absorbed by plants suffering oxidative stress induced by cadmium and aluminum ions, the probe generates prominent fluorescence signals, achieving real-time and sensitive imaging of oxidative stress of plants.

Intracellular Nitroreductase-Triggered "On" and "Enhanced" Photoacoustic Signals for Sensitive Imaging of Tumor Hypoxia.

Current molecular photoacoustic (PA) probes are designed with either stimulus-turned "on" or assembly-enhanced signals to trace biological analytes/events. PA probes based on the nature-derived click reaction between 2-cyano-6-aminobenzothiazole (CBT) and cysteine (Cys) (i.e., CBT-Cys click reaction) possess both "turn-on" and "enhanced" PA signals; and thus, should have higher sensitivity. Nevertheless, such PA probes, particularly those for sensitive imaging of tumor hypoxia, remain scarce. Herein, a PA probe NI-Cys(StBu)-Dap(IR780)-CBT (NI-C-CBT) is rationally designed, which after being internalized by hypoxic tumor cells, is cleaved by nitroreductase under the reduction condition to yield cyclic dimer C-CBT-Dimer to turn the PA signal "ON" and subsequently assembled into nanoparticles C-CBT-NPs with additionally enhanced PA signal ("Enhanced"). NI-C-CBT exhibits 1.7-fold "ON" and 3.2-fold overall "Enhanced" PA signals in vitro. Moreover, it provides 1.9-fold and 2.8-fold overall enhanced PA signals for tumor hypoxia imaging in HeLa cells and HeLa tumor-bearing mice, respectively. This strategy is expected to be widely applied to design more "smart" PA probes for sensitive imaging of important biological events in vivo in near future.

Endogenous mRNA-Powered and Spatial Confinement-Derived DNA Nanomachines for Ultrarapid and Sensitive Imaging of Let-7a.

DNA nanostructure-based signal amplifiers offer new tools for imaging intracellular miRNA. However, the inadequate kinetics and susceptibility to enzymatic hydrolysis of these amplifiers, combined with a deficient cofactor concentration within the intracellular environment, significantly undermine their operational efficiency. In this study, we address these challenges by encapsulating a localized target strand displacement assembly (L-SD) and a toehold-exchange endogenous-powered component (R-mRNA) within a framework nucleic acid (FNA) structure─20 bp cubic DNA nanocage (termed RL-cube). This design enables the construction of an endogenous-powered and spatial-confinement DNA nanomachine for ratiometric fluorescence imaging of intracellular miRNA Let-7a. The R-mRNA is designed to be specifically triggered by glyceraldehyde 3-phosphate dehydrogenase (GAPDH), an abundant cellular enzyme, and concurrently releases a component that can recycle the target Let-7a. Meanwhile, L-SD reacts with Let-7a to release a stem-loop beacon, generating a FRET signal. The spatial confinement provided by the framework, combined with the ample intracellular supply of GAPDH, imparts remarkable sensitivity (7.57 pM), selectivity, stability, biocompatibility, and attractive dynamic performance (2240-fold local concentration, approximately four times reaction rate, and a response time of approximately 7 min) to the nanomachine-based biosensor. Consequently, this study introduces a potent sensing approach for detecting nucleic acid biomarkers with significant potential for application in clinical diagnostics and therapeutics.