Specific Tolerance Research Articles

Characterization of earthworm α-amylases for dietary supplement development and biomass utilization.

Earthworms are useful soil-decomposing animals that possess various saccharification enzymes such as cellulases and amylases. Earthworms have also been traditionally used as antipyretic agents and medicines for preventing thrombotic diseases such as brain infarction. We previously developed a novel earthworm dietary supplement with fibrinolytic, cellulase, and amylase activities using high-pressure technology. However, the optimal temperature and pH required for amylase activity in bioindustry have not yet been investigated. In the present study, we purified and characterized two α-amylases of Eisenia fetida Waki, EfAMY1 and EfAMY2, which were monomeric enzymes of 63.8kDa and 64.0kDa, with specific activities of 69.2 and 40.4units/mg, respectively. The optimal pH was 5.5 for both enzymes, and the optimal temperatures were 45°C and 35°C for EfAMY1 and EfAMY2, respectively; however, the enzymes were stable over a wide pH range (5-10) and at high temperature (up to 40°C). These amylases showed higher specific activity and cold tolerance than those previously reported. These data should help to promote the development of E. fetida AMYs as functional dietary supplements and in biomass utilization.

An optimization method for stiffness configuration of flexible connectors for multi-modular floating systems

Stiffness of flexible connectors has great impacts on responses of multi-modular floating systems but how to properly layout the anisotropic stiffness of connectors is unsettled yet. This paper presents a general approach to determine the stiffness configuration for various wave conditions. A genetic-algorithm-based routine procedure is thus proposed, which is capable to handle quite large number of influential factors in a decision making process. The linear weighted sum method is used for the preferences on individual objectives according to specific engineering requirements, tolerances and constraints. In numerical studies of eight-modular floating system, the optimal stiffness configuration is found in a full scenario of weight combinations. It indicates that the combination of small longitudinal stiffness, large transversal and large vertical stiffness is favorable for most wave conditions. This work makes the tedious task of the stiffness design be easy.

An Examination of the Association Between Emotion Reactivity and Distress Tolerance Among College Students.

The goal of the present investigation was to examine associations between emotion reactivity in global and specific distress tolerance domains. Participants were 113 undergraduates (65.5% female, 82.3% Caucasian; Mage = 20.0, SD = 4.02, range = 18-45 years) who completed a battery of self-report measures. As hypothesized, the results indicate that, after controlling for sex and negative affectivity, greater levels of emotion reactivity were significantly associated with lower levels of global distress tolerance (12.5% unique variance) and the four specific distress tolerance domains: tolerance (8.6% unique variance), absorption (11.4% unique variance), appraisal (8% unique variance), and regulation (8.1% unique variance). These findings suggest that individuals who tend to react more strongly to their emotions have greater difficulty tolerating emotional distress, and interventions that target emotion reactivity may be an effective way to improve distress tolerance and reduce the risk of developing psychopathology among undergraduates.

RelB controls adaptive responses of astrocytes during sterile inflammation.

In response to brain injury or infections, astrocytes become reactive, undergo striking morphological and functional changes, and secrete and respond to a spectrum of inflammatory mediators. We asked whether reactive astrocytes also display adaptive responses during sterile IL-1β-induced neuroinflammation, which may limit tissue injury associated with many disorders of the central nervous system. We found that astrocytes display days-to-weeks long specific tolerance of cytokine genes, which is coordinated by NF-κB family member, RelB. However, in contrast to innate immune cells, astrocytic tolerance does not involve epigenetic silencing of the cytokine genes. Establishment of tolerance depends on persistent higher levels of RelB in tolerant astrocytes and its phosphorylation on serine 472. Mechanistically, this phosphorylation prevents efficient removal of RelB from cytokine promoters by IκBα and helps to establish tolerance. Importantly, ablation of RelB from astrocytes in mice abolishes tolerance during experimental neuroinflammation in vivo.

Treatment of Surgical Brain Injury by Immune Tolerance Induced by Peripheral Intravenous Injection of Biotargeting Nanoparticles Loaded With Brain Antigens.

Once excessive, neurological disorders associated with inflammatory conditions will inevitably cause secondary inflammatory damage to brain tissue. Immunosuppressive therapy can reduce the inflammatory state, but resulting infections can expose the patient to greater risk. Using specific immune tolerance organs or tissues from the body, brain antigen immune tolerance treatment can create a minimal immune response to the brain antigens that does not excessively affect the body's immunity. However, commonly used immune tolerance treatment approaches, such as those involving the nasal, gastrointestinal mucosa, thymus or liver portal vein injections, affect the clinical conversion of the therapy due to uncertain drug absorption, or inconvenient routes of administration. If hepatic portal intravenous injections of brain antigens could be replaced by normal peripheral venous infusion, the convenience of immune tolerance treatment could certainly be greatly increased. We attempted to encapsulate brain antigens with minimally immunogenic nanomaterials, to control the sizes of nanoparticles within the range of liver Kupffer cell phagocytosis and to coat the antigens with a coating material that had an affinity for liver cells. We injected these liver drug-loaded nanomaterials via peripheral intravenous injection. With the use of microparticles with liver characteristics, the brain antigens were transported into the liver out of the detection of immune armies in the blood. This approach has been demonstrated in rat models of surgical brain injury. It has been proven that the immune tolerance of brain antigens can be accomplished by peripheral intravenous infusion to achieve the effect of treating brain trauma after operations, which simplifies the clinical operation and could elicit substantial improvements in the future.

Facilitation mediates species presence beyond their environmental optimum

Species distributions are driven by abiotic conditions that filter species with specific traits and physiological tolerances and match them with their suitable environment. Plant–plant interactions can constrict (through competition) or loosen (through facilitation) the strength of these environmental filters, which in turn inhibit or enhance establishment and recruitment of plant species at a finer spatial scale. Although competition is often the focus of community assembly processes that further impede the entry of plant species into a site, facilitation is also important for potentially loosening environmental filters (especially climatic filters such as temperature and precipitation), ultimately enhancing species occurrence beyond their physiological optimum. We used multiple data sets from the arid site of Rambla del Saltador Valley to test the hypothesis that facilitation by a nurse-plant promotes the presence of herbaceous, beneficiary species beyond their environmental optimum relative to open sites. Furthermore, we propose that the median elevation and community composition of herbaceous species expands with the age of the nurse-plant, and we tested this hypothesis by examining 105 beneficiary species under 50 nurse-plant shrubs varying in age from 6 to 48 years old. We found nurse-plants both facilitate herbaceous species occurrence beyond their median elevation and support more diverse and a distinctly different composition of species in contrast to open sites. Specifically, herbaceous species that originate from a median elevation more than 600 to 700 m above the site only existed beneath nurse-plants, and below this median elevation, half the species only occurred below the nurse-plant. Moreover, the richness and elevation provenance of the herbaceous species increased with increasing nurse-plant age. Our results highlight the importance of facilitation for alleviating physiological strain (in support of the strain hypothesis) and mediating regional species distributions, which has implications for understanding species movements and community assembly at larger-scales under hotter and drier climates.

Dosimetric effect of body contour changes for prostate and head and neck volumetric modulated arc therapy plans.

Body contour changes are commonly seen in prostate and head and neck (H&N) patients undergoing volumetric modulated arc therapy (VMAT) treatments, which may cause a discrepancy between the planned dose and the delivered dose. Dosimetrists, radiation oncologists or medical physicists sometimes are required to visually assess the dosimetric impact of body contour changes and make a judgment call on whether further re‐assessment of the plan is needed. However, an intuitive judgment cannot always be made in a timely manner due to the complexity of VMAT plans as well as the complicated forms of body contour changes. This study evaluated the dosimetric effect of body contour changes for prostate and H&N patients to help with clinical decision‐making. By analyzing the one‐dimensional spatial dose profiles from the original body and the body with different body contour deformations, rules of thumb for dose percentage change and isodose line shift due to body contour changes were ascertained. Moreover, based on dose distribution comparison using three‐dimensional gamma analysis, the response of the clinical prostate and H&N VMAT plans to body contour changes was assessed. Within center specific dose deviation tolerances, prostate patients who had less than 2 cm single side body contour change or less than 1 cm uniform body contour change were unlikely to need plan re‐assessment; H&N VMAT plans with less than 1 cm uniform body contour change or less than 1 cm shoulder superior–inferior positional change were also unlikely to trigger further evaluation. Dose percentage change and isodose line shift were considered independently from the problem of volume changes in this study, but clinically, both aspects must be considered.

Bio-inspired design for enhanced damage tolerance of self-reinforced polypropylene/carbon fibre polypropylene hybrid composites

In this work, we investigate the toughness of an inter-layer Self-Reinforced Polypropylene/Carbon Fibre Polypropylene (SRPP/CFPP) cross-ply hybrid composite and devise strategies to improve two aspects of its damage tolerance: (i) increasing the energy dissipation capability and (ii) enhancing the impact damage tolerance. To this end, we introduced discontinuities in the form of laser-cuts across the fibres of the CFPP plies, tailoring two patterns of laser-cuts to meet each specific damage tolerance requirement. We conducted penetration impact and Double Edge Notched Tensile (DEN-T) tests. The DEN-T tests, analysed via the Essential Work of Fracture method, show that engineering the microstructure successfully diffused damage. This resulted in a great increase in energy dissipation capability — 90% higher than a reference non-engineered structure. Engineering the microstructure of impact samples has led to enhanced impact damage tolerance with increased energy dissipation at a sub-critical level and delayed critical failure.

Specific Immune Tolerance Response Triggered by Extracorporal Photopheresis after Heart Transplantation

Purpose Extracorporeal photopheresis (ECP) treatment following heart transplantation (HTx) may induce transplant tolerance. A monitoring tool for successful ECP treatment would allow determination of patient-specific duration and frequency of ECP therapy. We evaluated the immunological effects of ECP long-term therapy. Methods ECP therapy started 3 months after HTx (n=19). ECP therapy included a total of 5 cycles, each on 2 consecutive days every 4-8 wks over a mean period of 8.4±0.4 months. Blood samples were drawn prior to ECP (baseline), before each cycle and 4 months after the last cycle. Flow cytometry analysis of all samples specific subsets of both dendritic cells (DCs) and regulatory T cells (Tregs), which are involved in the immune tolerance response. Results Compared to baseline, ECP reduced CD4+ T cells (baseline: 23.2±9.2%, cycle 5: 23.6±3.4%, after ECP: 16.3±7.4%, p 0.01). DC subsets expressing blood dendritic cell antigen (BDCA) 1, 2, 3 or 4 increased during ECP but returned to baseline levels 4 months after ECP (BDCA1prior ECP: 42.1±13.4%, BDCA1cycle 5: 53.4±3.7%, BDCA1after ECP: 43.6±8.7%, BDCA2prior ECP: 20.2±9.1%, BDCA2cycle 5: 32.6±3.2%, BDCA2after ECP: 24.0±6.0%, BDCA3prior ECP: 73.2±17.8%, BDCA3cycle 5: 90.4±5.0%, BDCA3after ECP: 75.4±12.4%, BDCA4prior ECP: 21.6±10.0%, BDCA4cycle 5: 31.7±3.9%, BDCA4after ECP: 21.4±5.9%, all p≤0.01). Conclusion Our results suggest that a combined increase of BDCA1+, 2+, 3+ and 4+ DCs, total Tregs and the highly suppressive CD39+ Treg subset could be useful to monitor ECP therapy after HTx, and, to establish an individual ECP treatment schedule. Future studies need to explore ECP effects on immune cells in the context with clinical events like rejection or infection.

A novel electrical proximity index for voltage control in smart distribution system

In any power system the voltage profile is a crucial performance factor which must be contained in a specific tolerance range with respect to the nominal voltage value. This paper proposes a voltage control method for smart distribution system using a novel electrical proximity index. This index is independent of the system load dynamics. The method works on the electrical proximity of the control units, viz. distributed energy resources (DER) and flexible loads, from the point where voltage control needs to be incorporated. Depending on proximity of control units from the point of operation, the contribution of these units on voltage deviation are calculated for different time steps spanning over the day. The generation or demand of the control units, which are in close electrical proximity of the point of voltage deviation, are updated. Use of electrical proximity in choice of control units makes the control strategy faster and effective in controlling system voltage profile. The effectiveness of the proposed technique is demonstrated and evaluated for different types of distribution systems.

Tolerogenic Role of Myeloid Suppressor Cells in Organ Transplantation

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature cells of myeloid origin with a specific immune inhibitory function that negatively regulates the adaptive immune response. Since MDSC participate in the promotion of tolerance in the context of organ transplantation, therapeutic strategies that regulate the induction and development of MDSC have been the center of scientist attention. Here we review literature regarding induction of MDSC with demonstrated suppressive function among different types of allografts and their mechanism of action. While manipulation of MDSC represents a potential therapeutic approach for the promotion of donor specific tolerance in solid organ transplantation, further characterization of their specific phenotype, which distinguishes MDSC from non-suppressive myeloid cells, and detailed evaluation of the inhibitory mechanism that determines their suppressive function, is necessary for the realistic application of MDSC as biomarkers in health and disease and their potential use as immune cell therapy in organ transplantation.

A Systematic Study on the Effects of Dimensional and Materials Tolerances on Permanent Magnet Synchronous Machines Based on the IEEE Std 1812

In the process of designing and manufacturing an electrical machine, a systematic study of dimensional and material tolerances is of the utmost importance. This paper proposes a systematic method by which the effect of design specification variations on permanent magnet (PM) synchronous machine performance may be identified and quantified. The method combines design of experiments techniques, open-circuit and short-circuit physical measurements, and virtual test simulations conducted based on the recently approved IEEE Std 1812 testing guide. Three case studies, two provided by a spoke-type PM radial field machine configuration, in two designs with different electromagnetic loading, and an axial flux PM machine are discussed. It is shown that based on the output performance, out of specification tolerances for magnet remanence, steel grade, as well as dimensional variables, and stator to rotor eccentricity, may be identified under certain conditions. It is also exemplified that the ratings, magnetic loading, and configuration of the machine play critical roles and should be thoroughly considered as part of the studies.

There is an individual tolerance to mechanical loading in compression induced deep tissue injury

BackgroundDeep tissue injury is a type of pressure ulcer which originates subcutaneously due to sustained mechanical loading. The relationship between mechanical compression and damage development has been extensively studied in 2D. However, recent studies have suggested that damage develops beyond the site of indentation. The objective of this study was to compare mechanical loading conditions to the associated damage in 3D. MethodsAn indentation test was performed on the tibialis anterior muscle of rats (n = 39). Changes in the form of oedema and structural damage were monitored with MRI in an extensive region. The internal deformations were evaluated using MRI based 3D finite element models. FindingsDamage propagates away from the loaded region. The 3D analysis indicates that there is a subject specific tolerance to compression induced deep tissue injury. InterpretationIndividual tolerance is an important factor when considering the mechanical loading conditions which induce damage.

Representation of Graded Materials and Structures to Support Tolerance Specification for Additive Manufacturing Application

Additive manufacturing (AM) has enabled control over heterogeneous materials and structures in ways that were not previously possible, including functionally graded materials and structures. This paper presents a novel method for representing and communicating heterogeneous materials and structures that include tolerancing of geometry and material together. The aim of this paper is to propose a means to specify nominal materials, nominal structures and allowable material variations in parts, including (a) explicit material and structural transitions (implying abrupt changes) and (b) functional transitions to support single and multiple material and structural behaviors (implying designed function-based gradients). The transition region combines bounded regions (volumes and surfaces) and material distribution and structural variation equations. Tolerancing is defined at two levels, that of the geometry including bounded regions and that of the materials. Material tolerances are defined as allowable material variations from nominal material fractions within a unit volume at a given location computed using material distribution equations. The method is described thorough several case studies of abrupt transitions, lattice-based transitions, and multimaterial and structural transitions.

TCR Retrogenic Mice as a Model To Map Self-Tolerance Mechanisms to the Cancer Mucosa Antigen GUCY2C.

Characterizing self-tolerance mechanisms and their failure is critical to understand immune homeostasis, cancer immunity, and autoimmunity. However, examination of self-tolerance mechanisms has relied primarily on transgenic mice expressing TCRs targeting well-characterized, but nonphysiologic, model Ags, such as OVA and hemagglutinin. Identifying TCRs directed against bona fide self-antigens is made difficult by the extraordinary diversity of TCRs and the low prevalence of Ag-specific clones (<10-100 naive cells per organism), limiting dissection of tolerance mechanisms restricting immunity to self-proteins. In this study, we isolated and characterized TCRs recognizing the intestinal epithelial cell receptor and colorectal cancer Ag GUCY2C to establish a model to study self-antigen-specific tolerance mechanisms. GUCY2C-specific CD4+ effector T cells were isolated from immunized, nontolerant Gucy2c -/- mice. Next-generation sequencing identified GUCY2C-specific TCRs, which were engineered into CD4+ T cells in vitro to confirm TCR recognition of GUCY2C. Further, the generation of "retrogenic" mice by reconstitution with TCR-transduced hematopoietic stem cells resulted in normal CD4+ T cell development, responsiveness to immunization, and GUCY2C-induced tolerance in recipient mice, recapitulating observations in conventional models. This retrogenic model can be employed to define self-tolerance mechanisms restricting T and B cell responses to GUCY2C to optimize colorectal cancer immunotherapy without autoimmunity.

Abstract P1-14-01: Final results of NorBreast-231, a randomized phase II study evaluating weekly oral vinorelbine versus weekly paclitaxel as first-line chemotherapy in patients with advanced breast cancer

Abstract Background: Single-agent chemotherapy (CT) is the standard treatment option in endocrine receptor (ER)-positive advanced breast cancer (ABC) after failure of endocrine therapy (ET) or in patients (pts) without visceral crisis. Both weekly paclitaxel (WP) and oral vinorelbine (OV) are among the recommended treatment options in this setting. The aim of this study was to evaluate the efficacy and safety profiles of OV and WP in a face to face study. Material and methods: Pts with ER-positive, HER2-negative ABC, with an age ≥18 years and with a documented locally recurrent or metastatic involvement previously untreated by CT were eligible. Pts were randomized to receive, as first-line CT, 3 weekly-cycles of either: ARM A: weekly OV, given as a 80 mg/m2 dose (following a first cycle at 60 mg/m2, dose escalation to 80 in the absence of grade 3 or 4 toxicity at cycle 1); ARM B: WP 80 mg/m2 per week. Primary endpoint was disease control rate (DCR). Pts were stratified according to prior taxane CT and visceral metastases. Results: 131 pts have been treated (OV: 66, WP: 65). Baseline pts characteristics (Arms OV/WP): median age 58/61 years; median number of prior ET: 2/2; prior (neo) adjuvant CT 74/72%; prior anthracycline 67/62%; prior taxane: 41/42%; &amp;gt;3 metastatic sites 42/48%; visceral metastases 79/79%. Median number of cycles (range): 6(1-55)/7(1-44); dose escalation of OV was performed in 75% of pts. Safety: most common non-hematological related G3/4 adverse events per pt were fatigue 8/2%, peripheral neuropathy 0/5%, nausea 3/0%, diarrhoea 3/2%, vomiting 3/0%, constipation 3/2%, alopecia (G2) 2/34%, no toxic deaths; febrile neutropenia was present in 2/0% of pts. Quality of life: over time, no major differences between both arms have been observed. Efficacy: DCR in the intent-to-treat population was [95%CI] 75.8 [63.6-85.5] /75.4 [63.1-85.2]%; overall response rate 20/40%; median progression-free survival: 5.5/6.4 months. Median overall survival was: OV 27.6/WP 22.3 months. Conclusion: Both OV and WP reached similar DCR rates of 75%. Each regimen presented a specific tolerance profile, with, in particular, a lower incidence of alopecia and peripheral neuropathy with OV. OV and WP are valid first-line CT options for ER-positive/HER2-negative pts with ABC. Citation Format: Aapro MS, Hegg R, Ruiz Borrego M, Staroslawska E, Morales S, Cinieri S, De Freitas Junior R, Garcia Estevez L, Szombara E, Hervieu H, Groc M, Villanova GR. Final results of NorBreast-231, a randomized phase II study evaluating weekly oral vinorelbine versus weekly paclitaxel as first-line chemotherapy in patients with advanced breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-14-01.

Fracture mechanics based prediction of undercut tolerances in industry

Undercuts are geometrical discontinuities or grooves along the toe of a weld caused by loss of the parent material that remain unfilled by weld metal. Regardless of their causes, undercuts can be found in structures and components, in the majority of joints and most of the welding processes. Due to their frequency of appearance in welded structures and their detrimental effects on component life, undercut acceptance criteria had to be regulated by construction codes and standards. Depending on the area where the component is in service, specific tolerances must be satisfied in order to accept or reject the part. In general, undercut depth is considered to be the limiting parameter for this kind of imperfection. However, there is currently in industry no agreement about which value of depth is tolerable for a desired fatigue strength. The purposes of the present paper are twofold. First, to summarise the state of art associated to undercut tolerances in different codes, standards and recommendation documents, for different industries and applications. Secondly, to employ a fracture mechanics based methodology to predict safe undercut dimensions for butt welds subjected to fatigue. Predictions are in good agreement with experimental results from literature, and proposed method proved to be helpful for assessing weld discontinuities.

Tolerance analysis of gear trains by static analogy

Assembly-level geometric errors such as backlash, center distance errors and shaft misalignments may adversely affect the operation of a gear train. The tolerance analysis method proposed in the paper estimates these errors from tolerance specifications on gears and mounting parts (shafts, bearings, housings). The problem is solved by analogy with an equivalent problem of force analysis: on a properly defined structure, external forces correspond to the assembly-level error, and calculated internal forces and support reactions provide the sensitivities of part tolerances on the total error. Previously developed for generic assemblies, the approach proves especially simple for gear systems compared to existing methods of tolerance analysis, as it relies upon structural analysis procedures that are customary in mechanical design. The method based on static analogy includes a two-level classification of geometric errors, which helps overcome the complexity of tolerance analysis problems for gearings. Two examples of gear trains of different types and configurations are presented to demonstrate the calculation procedure and verify its correctness by comparison with geometric considerations.

Uncovering Differentially Methylated Regions (DMRs) in a Salt-Tolerant Rice Variety under Stress: One Step towards New Regulatory Regions for Enhanced Salt Tolerance.

Chromatin structure, DNA methylation, and histone modifications act in a concerted manner to influence gene expression and therefore plant phenotypes. Environmental stresses are often associated with extensive chromatin rearrangements and modifications of epigenetic levels and patterns. Stress-tolerant plants can be a good tool to unveil potential connections between specific epigenetic modifications and stress tolerance capacity. We analyzed genome wide DNA methylation of a salt-tolerant rice variety under salinity and identified a set of differentially methylated regions (DMRs) between control and stress samples using high-throughput sequencing of DNA immunoprecipitated with the 5-methylcytosine antibody (MeDIP-Seq). The examination of DNA methylation pattern at DMRs regions revealed a general tendency for demethylation events in stress samples as compared to control. In addition, DMRs appear to influence the expression of genes located in their vicinity. We hypothesize that short regions as DMRs can shape the chromatin landscape of specific genomic regions and, therefore, may modulate the function of several genes. In this sense, the identification of DMRs represents one step towards to uncover new players in the regulation of stress-responsive genes and new target genes with potential application in enhancement of plant salinity-tolerance.

Ionic Pyridinium-Oxazole Dyads: Design, Synthesis, and Application in Mitochondrial Imaging.

We recently developed an oxidative intramolecular 1,2-amino-oxygenation reaction, combining gold(I)/gold(III) catalysis, for accessing structurally unique ionic pyridinium-oxazole dyads (PODs) with tunable emission wavelengths. On further investigation, these fluorophores turned out to be potential biomarkers; in particular, the one containing -NMe2 functionality (NMe2-POD) was highly selective for mitochondrial imaging. Of note, because of mitochondria's involvement in early-stage apoptosis and degenerative conditions, tracking the dynamics of mitochondrial morphology with such imaging technology has attracted much interest. Along this line, we wanted to build a library of such PODs which are potential mitochondria trackers. However, Au/Selecfluor, our first-generation catalyst system, suffers from undesired fluorination of electronically rich PODs resulting in an inseparable mixture (1:1) of the PODs and their fluorinated derivatives. In our attempt to search for a better alternative to circumvent this issue, we developed a second-generation approach for the synthesis of PODs by employing Cu(II)/PhI(OAC)2-mediated oxidative 1,2-amino-oxygenation of alkynes. Thes newly synthesized PODs exhibit tunable emissions as well as excellent quantum efficiency up to 0.96. Further, this powerful process gives rapid access to a library of NMe2-PODs which are potential mitochondrial imaging agents. Out of the library, the randomly chosen POD-3g was studied for cell-imaging experiments which showed high mitochondrial specificity, superior photostability, and appreciable tolerance to microenvironment changes with respect to commercially available MitoTracker green.