Expansion Ring Research Articles

Machine learning predicts conventional imaging metastasis-free survival (MFS) for oligometastatic castration-sensitive prostate cancer (omCSPC) using prostate-specific membrane antigen (PSMA) PET radiomics

PurposeThis study investigated imaging biomarkers derived from PSMA-PET acquired pre- and post-metastasis-directed therapy (MDT) to predict 2-year metastasis-free survival (MFS), which provides valuable early response assessment to improve patient outcomes. Materials/MethodsAn international cohort of 117 oligometastatic castration-sensitive prostate cancer (omCSPC) patients, comprising 34 from John Hopkins Hospital (JHH) and 83 from Baskent University (BU), were treated with stereotactic ablative radiation therapy (SABR) MDT with both pre- and post-MDT PSMA-PET/CT scans acquired. PET radiomic features were analyzed from a CT-PET fusion defined gross tumor volume ((GTV) or zone 1), and a 5 mm expansion ring area outside the GTV (zone 2). A total of 1748 PET radiomic features were extracted from these zones. The six most significant features selected using the Chi2 method, along with five clinical parameters (age, Gleason score, number of total lesions, untreated lesions, and pre-MDT prostate-specific antigen (PSA)) were extracted as inputs to the models. Various machine learning models, including Random Forest, Decision Tree, Support Vector Machine, and Naïve Bayesian, were employed for 2-year MFS prediction and tested using leave-one-out and cross-institution validation. ResultsSix radiomic features, including Total Energy, Entropy, and Standard Deviation from pre-PSMA-PET zone 1, Total Energy and Contrast from post-PSMA-PET zone 1, and Entropy from pre-PSMA-PET zone 2, along with five clinical parameters were selected for predicting 2-year MFS. In a leave-one-out test with all the patients, random forest achieved an accuracy of 80 % and an AUC of 0.82 in predicting 2-year MFS. In cross-institution validation, the model correctly predicted 2-year MFS events with an accuracy of 75 % and an AUC of 0.77 for patients from JHH, and an accuracy of 78 % and an AUC of 0.80 for BU patients, respectively. ConclusionOur study demonstrated the promise of using pre- and post-MDT PSMA-PET-based imaging biomarkers for MFS prediction for omCSPC patients.

External aortic annuloplasty with a dedicated expansible ring improves outcomes in remodeling root repair compared with homemade Dacron ring

ObjectivesIn remodeling valve-sparing root replacement with external annuloplasty, we compare long-term outcomes of a calibrated expansible extra-aortic ring with a homemade Dacron ring. MethodsAll patients (2003-2020) operated for root aneurysm with/without aortic insufficiency (AI) were included. The standardized CAVIAAR (conservation aortique valvulaire dans les insuffisances aortiques et anévrysmes de la racine-Valve sparing in aortic insufficiencies and root aneurysms) technique was root remodeling and external annuloplasty ring with the EXTRA-AORTIC Ring or homemade Dacron ring. ResultsAmong 486 patients (age 52.3 ± 14.0 years) operated for root aneurysm, 375 (repair rate: 77.1%) underwent root remodeling with annuloplasty (extra-aortic ring, n = 289, vs Dacron ring, n = 86). At 10 years (median follow-up, 4.08 years’ interquartile range, 1.95-7.61), unmatched and matched analysis showed that patients with extra-aortic ring had greater survival, similar to the general population (93.3% vs 79.9%, P = .097), lower reoperation incidence (2.0% vs 9.7%, P = .0098), and lower AI grade >2 recurrence (1.9% vs 11.2%, P = .0042), compared with patients with a Dacron ring. Mixed-effect model showed that with extra-aortic ring annuloplasty, annular dilation over time (P = .0033) was prevented and, compared with the homemade Dacron ring, root expansibility was better preserved (3.22% vs 2.12%, P = .002) and mean transvalvular gradient was lower (6.58 mm Hg vs 7.94 mm Hg, P = .001). Tricuspid and bicuspid valves with extra-aortic ring had similar reoperation (4.3% vs 0.85%, P = .65) and AI grade >2 incidence (2.7% vs 1.2%, P = .61), expansibility (P = .29), and diameter (P = .47), whereas mean transvalvular gradient was lower for tricuspid valves (5.58 mm Hg vs 7.60 mm Hg, P = .004). ConclusionsValve-sparing root remodeling with calibrated expansible extra-aortic ring annuloplasty improves the outcomes of reoperation and recurrent AI compared with a homemade Dacron ring. It prevents dilation and maintains physiological root dynamics for durable valve repair.

Corneal morphology following use of Malyugin versus B-hex pupil expansion rings in small pupil phacoemulsification

Aim: The aim of the study is to evaluate changes in corneal parameters following the use of the Malyugin ring (MR) and B-Hex ring (BhR) in small pupil phacoemulsification. Methods: A prospective cross-sectional study. 51 eyes with small pupil underwent phacoemulsification with the use of MR and BhR as pupil expansion techniques. Best-corrected visual acuity (BCVA), endothelial cell counts density (ECD), coefficient-of-variation (CV), hexagonality, central corneal thickness (CCT), and intraocular pressure (IOP) were recorded on preoperative day and postoperative day 1 and day 30. Results: Mean age at presentation was 70.9 ± 4.1 years. The most common cause for small pupils was alpha-blockers used in benign prostate hypertrophy, followed by diabetes mellitus and pseudo-exfoliation syndrome. Mean preoperative BCVA (3/60–6/12), IOP (17.12 ± 2.81 mmHg), CCT (530.96 ± 44.47 μ), ECD (2347.96 ± 298.09 cells/mm2), 6A (48.92% ± 6.34%) and CV (39.50 ± 3.49) changed to BCVA (6/9–6/6), IOP (18.69 ± 1.91 mm of Hg), CCT (536.04 ± 37.61 μ), endothelial cell count (2201.15 ± 276.75 cells/mm2), 6A (45.12% ±4.99%), and CV (37.57 ± 3.37) at day 30 postoperatively after use of MR. Similarly, mean preoperative BCVA (3/60–6/12), IOP (16.40 ± 2.42 mmHg), CCT (532.40 ± 36.14 μ), ECD (2433.68 ± 162.01 cells/mm2), 6A (48.84% ± 3.73%), and CV (39.36 ± 3.915) changed to BCVA (6/9–6/6), IOP (17.68 ± 2.75 mmHg), CCT (546.88 ± 31.25 μ), ECD (2322.08 ± 167.97 cells/mm2), 6A (46.36% ± 3.25%) and CV (38.96 ± 4.43) at day 30 post-operatively after use of BhR. The average change was clinically insignificant at day 30. Conclusion: MR and BhRs are safe pupil expansion devices and the corneal parameters are in the acceptable range of any routine phacoemulsification for senile cataracts. Nevertheless, B-hR shows relatively less alteration in corneal parameters, when compared to MR.

Automatic Prediction of Metastasis-Free Survival (MFS) Using Prostate-Specific Membrane Antigen (PSMA) PET for Oligometastatic Castration-Sensitive Prostate Cancer (omCSPC)

Recent data have shown the promise of metastasis-directed therapy (MDT) to improve outcomes in omCSPC patients. Response biomarkers are still needed to identify patients at an early time point who will not respond to the treatment. We have shown that PSMA PET-CT SUVmax changes over time may be a useful response biomarker that correlates with MFS, an important endpoint in these omCSPC patients. This study investigated radiomic imaging biomarkers derived from PSMA-PET acquired pre- and post-MDT for MFS prediction, which may provide better features to discriminate response in the future to improve the outcome of these patients. We accrued an international multi-institutional cohort of omCSPC patients treated with stereotactic ablative radiation therapy (SABR) MDT. The cohort includes 32 patients from Institution 1 (USA) and 38 patients from Institution 2 (Europe). Both pre- and 6-month post-treatment PSMA-PET/CT were acquired. Combat was used for data harmonization in the image domain to minimize imaging variations across institutions. We defined the GTV volume as zone 1 and a 3-5 mm expansion ring area outside the GTV as zone 2 for radiomics analysis. 874 radiomics features (214 original and 660 wavelet filtered features) were extracted from both zones using open-source software and used together for MFS prediction. Function Chi2 was used to select the most significant five features. Several machine learning models (Random Forest, Logistic regression, Support Vector Machine, Naïve Bayesian) were implemented to predict MFS. The models were tested using both a leave-one-out strategy and cross-validation across the two institutions. In the leave-one-out biomarker using 70 patients, random forest achieved the best accuracy, with MFS predicted correctly for 56 (80% of 70) patients. The five radiomic features identified based on their ability to predict MFS included Entropy, Skewness, and Compactness from zone 1, Skewness, and Mesh volume from zone 2. In the cross-institution tests, random forest predicted MFS correctly for 24 (75% of 32) patients when being trained using 38 Institution 2 patients and validated against 32 Institution 1 patients. Vice versa, the model predicted MFS correctly for 28 (74% of 38) patients when being trained using Institution 1 patients and validation using Institution 2 patients. The five features identified for prediction included Entropy and Skewness from both zones and Flatness from zone 1. Our study demonstrated the promise of using pre- and post-MDT PSMA-PET-based imaging radiomic biomarkers for MFS prediction for omCSPC patients. Imaging biomarkers predictive of MFS were identified in both GTV and the ring area outside GTV. Over 74% prediction accuracy was achieved in the cross-institution validation test. The model provides a valuable tool for prognosis prediction early following MDT, which opens up a unique opportunity for monitoring or treatment interventions for patients identified with poor prognoses to improve outcomes.

Application of RFID Corrosion Environment Sensing System to Repair Work and Results of 10-year study

To perform preventive maintenance of reinforcing steel corrosion in reinforced concrete, developed an RFID corrosion environment detection system that can wirelessly measure iron sensors that simulate reinforcing bars. This system can be embedded in concrete for a long period of time according to the life cycle of the structure, and semiconductor parts can be used for the passive RFID used in the communication interface. Therefore, it is necessary to confirm long-term durability. In this study, applied an RFID corrosion environment detection system to the repair work of bridge piers in addition to the conventional method of diagnosing rebar corrosion, and this paper report the results of our research conducted over a period of 10 years. The RFID corrosion environment detection system was compared with the expansion ring sensor system and the rebar self-potential measurement results. In addition, EPMA was used to analyze the chloride ion permeation of cores sampled from 5- and 10-year-old structures. The reaction results of the RFID corrosion environment sensor were compared with the permeation of chloride ions inside the structure.

An investigating on explosive expanding fracture of 45 steel cylinders by SPH method

The expanding fracture of ductile alloy cylinder subject to the explosion includes multiple fracture modes, such as tensile, shear, and mixed tensile-shear fracture. The mechanism and the factors influencing the fracture processes are still enigmatic and far from understood. In this paper, the smoothed particle hydrodynamics (SPH) method is used to simulate the explosion experiment of 45 steel cylinders shell with different charges of JOB-9003 and RHT-901. The shear fracture, tension-shear mixed fracture modes and the evolution process of cylindrical shell with different charges are discussed. The simulation results are consistent with the experimental trend. The SPH results show that due to the propagation and reflection of shock wave between the inner and outer surfaces of cylinder during the loading stage of detonation wave, the distribution of equivalent plastic strain on wall-thickness of the cylinder is a convex shape, i.e. the strain in the middle of wall-thickness is larger than that of in the inner and outer walls; when loading by a higher explosive pressure (JOB-9003), the fracture cracks initiate from the middle of wall-thickness, and then develop to the inner and outer walls along the direction of maximum shear in loading stage, showingthe shear fracture mode. However, under the loading caused by charge RHT-901 with relatively low pressure, although the crack still starts from the middle of wall-thickness and propagates along the shear direction, the shear crack could not grow through the section of the wall completely in the loading stage; then the cylinder experiences the stage of free expansion, the stress state of unbroken zone changes into triaxial tensile stress state and the structural instability, similar to “necking” occurs in the unbroken zone. Consequently, the cracks turn from the shear direction to the necking zone along the radial direction, showing the mixed tensile-shear fracture mode. The proportion of tension and shear cracks is related to the occurrence time of structural instability. The results show that the explosion expanding-fracture process of a metal cylinders involves the interaction between shock wave and cylinder structure, and cannot be treated as that of a series of expansion rings.

9-Cyanopyronin probe palette for super-multiplexed vibrational imaging

Multiplexed optical imaging provides holistic visualization on a vast number of molecular targets, which has become increasingly essential for understanding complex biological processes and interactions. Vibrational microscopy has great potential owing to the sharp linewidth of vibrational spectra. In 2017, we demonstrated the coupling between electronic pre-resonant stimulated Raman scattering (epr-SRS) microscopy with a proposed library of 9-cyanopyronin-based dyes, named Manhattan Raman Scattering (MARS). Herein, we develop robust synthetic methodology to build MARS probes with different core atoms, expansion ring numbers, and stable isotope substitutions. We discover a predictive model to correlate their vibrational frequencies with structures, which guides rational design of MARS dyes with desirable Raman shifts. An expanded library of MARS probes with diverse functionalities is constructed. When coupled with epr-SRS microscopy, these MARS probes allow us to demonstrate not only many versatile labeling modalities but also increased multiplexing capacity. Hence, this work opens up next-generation vibrational imaging with greater utilities.

2 + 2] Cycloaddition and Bond Cleavage of Boron Nitride Cages with Iminoborane: A DFT Study

We have studied the addition of reaction between iminoborane HBNH with the BnNn cages (n = 12, 16, 28 and 36) for the chemoselectivity (BN bond cleavage and expansion ring vs [2 + 2] cycloaddition) and regioselectivity (square–hexagon junctions vs hexagon–hexagon) of the reaction. Based on our results, the iminoborane molecule can either selectively break a B–N bond of the BN cages, expanding the square ring of the BN cage to a larger one at the surface, or undergo a [2 + 2]-cycloaddition on the BNNT surface. These reactions exhibit a depending on the reactive site of the cages. The square–hexagon B–N bond of the cages prefer bond-cleavage-ring-expansion processes, while hexagon–hexagon B–N bonds follow [2 + 2] cycloaddition reaction. Overall, all reactions are is exothermic while bond-cleavage-ring-expansion processes are a bit more favorable than [2 + 2] cycloadditions with smaller barrier heights. While complexes of iminoborane with hexagon–hexagon bonds at the middle of the larger cages resemble [2 + 2]-cycloaddition, BN bond cleavage also occurred and HBNH acts as a bridge at the top of the decagon. The larger values of HOMO–LUMO gaps for the most stable configurations also indicate kinetically preference the BN bond cleavage and ring expansion processes than the [2 + 2]-cycloaddition reactions.

Simulation of advanced cataract surgery - validation of a newly developed test.

PurposeTo develop and investigate an Eyesi simulator‐based test for the more experienced cataract surgeon for evidence of validity.MethodsThe study was a prospective interventional cohort study and carried out at the Copenhagen Academy for Medical Education and Simulation. The Eyesi Simulator was used for the test which was developed by three expert cataract surgeons. Ten cataract surgeons (>250 surgeries performed) and ten ophthalmic residents performed two repetitions of the test. The test consisted of four modules: Iris Expansion Ring insertion – level 1, Iris Expansion Ring extraction – level 2, Capsulorhexis – level 3 and Anterior Vitrectomy – level 6.ResultsInternal consistency reliability showed Cronbach’s alpha of 0.63. Test–retest reliabilities were significant for Iris Expansion Ring extraction – level 2 (p = 0.012) and Capsulorhexis – level 3 (p = 0.018). Differences between the two groups were only significant in both repetitions for the Iris Expansion Ring extraction – level 2 (p < 0.001 and p = 0.041, respectively). Furthermore, we found a statistically significant difference between the mean module scores for novices and the more experienced surgeons for Iris Expansion Ring insertion – level 1 (p = 0.021) and Capsulorhexis – level 3 (p = 0.019) in the first repetition.ConclusionThe investigated modules show evidence of validity within several aspects of Messick’s framework. However, the evidence is not strong enough to apply the test for certification purposes of cataract surgeons, but the modules may still be relevant in the training of advanced cataract surgical procedures.

Process parameter optimisation of a minster draw‐redraw system

Non‐conformance in Unit Depth Value (UDV) of expansion rings for metal cans makes them prone to major defects, such as swells and distortions, during the Drawing/Redrawing industrial process. In this paper, with the aim of improving the manufacturing process quality, the process parameters for the Minster Draw/Redraw machine at a generic company are optimised so as to obtain the desired UDV. The Taguchi method is used to determine the most influential process parameters. Nine experiments have been performed with four selected parameters, namely, Upper Blank Holder Pressure, Lower Blank Holder Pressure, Profile Pad Pressure, and Inner Ram Value. A multiple‐linear regression analysis is also conducted to demonstrate the relationship between UDV and the considered parameters. The best settings for the respective process parameters are obtained via Analysis of Means (ANOM). Furthermore, Analysis of Variance (ANOVA) shows that the Inner Ram Value is the process parameter that most significantly affects the formation of expansion rings. The same methodology proposed in this study can easily be extended to find the optimum settings of process parameters for different can heights. Finally, an equation is formulated to predict the setting values of the most significant process parameters under user‐specified UDVs.

Series of cataract surgeries with I-ring pupil expansion ring

Series of cataract surgeries with I-ring pupil expansion ring

Hemi-remodeling root repair with expansible aortic ring annuloplasty

Hemi-remodeling root repair with expansible aortic ring annuloplasty

Remodelling root repair with expansible aortic ring annuloplasty

Remodelling root repair with expansible aortic ring annuloplasty

New use of a pupillary expansion ring to avoid intraoperative positive vitreous pressure during triple procedures

Positivevitreous pressure can complicate cataract surgery during a triple procedure by inadvertently extending the capsulorhexis. This occurs because the procedure is open sky and positive vitreous pressure cannot be countered by injecting ophthalmic viscosurgical devices. We describe a new use of a pupillary expansion ring (Malyugin) to achieve a stable open anterior chamber under open sky during triple procedures. The scrolls are tucked under cut margins of the host cornea to create the capsulorhexis, the cataractous nucleus is removed, and an intraocular lens (IOL) is implanted in the bag. This technique is especially useful in cases of hypermature cataract and nondilating pupils with positive vitreous pressure in patients having triple procedures. The technique provides a stable open anterior chamber, increasing to the safety of the procedure and the chance of achieving a continuous curvilinear capsulorhexis and IOL implantation in the capsular bag.

Addition of borazine to boron nitride nanotubes: [2+2] cycloaddition or bond cleavage

We have studied the addition of borazine to different armchair and zigzag BNNTs to investigate the chemoselectivity (BN bond cleavage vs. [2+2] cycloaddition) and regioselectivity (parallel vs. oblique addition) of the reaction. Based on our results, the borazine can either selectively break a B–N bond of the BN nanotubes, expanding the hexagonal ring of the tube to larger one at the surface, or undergo a [2+2]-cycloaddition on the BNNT surfaces. Both of these reactions exhibit a dependence on the chirality and active site of the tubes. Diagonal BN bonds of the zigzag BN tubes, either at the edges or at the middle of the tubes, are cleaved; but BN bonds parallel to the tube axis undergo [2+2] cycloaddition reactions. In contrast, diagonal BN bonds of the armchair BNNTs prefer cycloaddition, and BN bonds perpendicular to the tube axis follow BN bond cleavage and expansion ring. Overall, the B–N bond cleavage and expansion ring reactions of the borazine and the BN nanotubes are exothermic while [2+2] cycloaddition reactions of the BN nanotubes and borazine are endothermic. Reaction energies decrease with the increase of the diameter of the tube. [2+2] cycloadditions decrease the band gaps of the BNNTs by only about 4.3–19.9% while bond cleavage process increases the band gaps of the BNNTs, by about 1.4–7.9%.

Iris hooks versus a pupil expansion ring: Operating times, complications, and visual acuity outcomes in small pupil cases

To compare iris hooks and a pupil expansion ring (Malyugin ring) in eyes with a small pupil. Epsom and St. Helier University National Health Service Trust, London, United Kingdom. Retrospective case series. Patients who had primary phacoemulsification cataract surgery from January 1, 2012, to December 30, 2016, were included. Combined procedures and surgeons with fewer than 50 cases were excluded. Anonymized data were demographics, surgeon grade, case complexity, iris hooks or Malyugin ring use, posterior capsule rupture, zonular fiber rupture or dialysis, vitreous loss, operating time, postoperative complications, and visual acuity. Of the 9552 cases included, 425 (4.4%) had a small pupil, 314 of which required a pupil expansion ring and 95 iris hooks. Compared with no pupil expander, iris hooks were associated with an additional operating time of 14minutes for consultants and 24minutes for trainees. The pupil expansion ring was associated with an additional operating time of 4minutes and 6minutes, respectively. Neither pupil expander was associated with more intraoperative complications. The pupil expansion ring was associated with higher postoperative anterior uveitis and corneal edema rates. Pupil expander cases achieved equivalent visual acuity gains. The pupil expansion ring and iris hooks were safe and effective in minimizing intraoperative complications in eyes with a small pupil. The pupil expansion ring was faster to use than iris hooks. Monitoring for signs of postoperative anterior uveitis or cornea edema with careful insertion or removal of pupil expansion rings is advocated.

Phacoemulsification in adult patients with post-uveitis complicated cataract

Objective: To evaluate the difficulties, complications and outcome of cataract surgery in patients with complicated cataract after anterior uveitis. Methods: A retrospective study on 37 patients who suffered phacoemulsification surgery for post-uveitis complicated cataract in the period 2009-2014 was performed. 43 eyes underwent surgery. Results: Posterior synechiae were present in 25 eyes. Posterior synechiolysis ensured large pupil in 15 eyes, and, in 14 eyes, the use of iris hooks or pupil expansion ring was necessary for surgery. Posterior capsule rupture was reported in 1 eye. Opacified and thick posterior capsule was noticed in 6 eyes. After surgery, transient rising of intraocular pressure was noticed in 4 eyes and prolonged postoperative inflammation was present in 3 eyes. Posterior capsule opacification was the most frequent issue (9 eyes) and cystoid macular oedema was reported in 2 eyes. Conclusions: Post-uveitis complicated cataract surgery presents specific difficulties and postoperative complications are present in these patients, like prolonged postoperative inflammation and cystoid macular oedema.

Simultaneous pupil expansion and displacement for femtosecond laser–assisted cataract surgery in patients with lens ectopia

We describe a new approach for cataract surgery in ectopia lentis associated with an inadequately dilated pupil. A Malyugin ring 2.0 is first positioned in the eye to expand the pupil. One of the ring coils is then temporarily sutured to the limbal area with 10-0 polypropylene. With this maneuver, the pupillary expansion ring is placed in alignment with the center of the ectopic lens. Femtosecond laser anterior capsulotomy and lens fragmentation is then performed. Next, the temporary suture is released, a capsular hook(s) is placed to support the lens, and the lens is emulsified. A modified capsular tension ring is then inserted and sutured to the ciliary sulcus to center the capsular bag and the intraocular lens is implanted. This new technique for patients with insufficiently dilated pupils associated with ectopia lentis has the potential to improve surgical results and minimize complications in selected cases.

Efficacy of the Canabrava Ring (pupil expansion device) in cataract surgery for eyes with small pupils: the first 30 cases.

To evaluate the outcomes of the first 30 cataract surgeries performed with a new disposable, injector-free, small-pupil expansion device. This consecutive case series included 30 eyes from 29 patients who underwent cataract surgery using a new disposable small-pupil expansion device called the Canabrava Ring (AJL Ophthalmic S.A, Spain). It is the first iris expansion ring produced with indents that do not align with each other in the superior and inferior regions, resulting in a small vertical length (0.4 mm) that minimizes the risk of endothelial contact. All eyes had poorly dilated pupils of less than 5 mm preoperatively. Fifteen eyes had significant infective or traumatic pathologies preoperatively. Vertical and horizontal pupil diameters were evaluated preoperatively, intraoperatively, and 1 month postoperatively. The mean patient age was 64 ± 11.8 (standard deviation) years. The Canabrava Ring remained engaged throughout all surgeries, except one. All pupils were intraoperatively expanded to a diameter of 6.3 mm. Although preexisting pathology on the innervation of the pupils, the mean pupil diameter returns to a close preoperative size after 1 month surgery. The mean pupil diameters postoperatively and preoperatively were 4.41 and 3.77 mm, respectively (p<0.05). Postoperative complications occurred in eight eyes (one toxoplasmosis reactivation, one retinal detachment, one posterior capsule rupture, one posterior capsule opacification, and four posterior synechiae). These complications occurred in eyes with preexisting traumatic or infective pathologies or synechiae. The Canabrava Ring is effective for expanding and maintaining expansion of small pupils in cataract surgery. The increase in postoperative pupil diameter is clinically diminutive and can most likely be attributed to preexisting pathologies affecting pupil innervation. Further large-scale studies are required to support the present findings.

Auxetic and Negative Thermal Expansion Structure Based on Interconnected Array of Rings and Sliding Rods

An exploration by analytical method has been made herein for a mechanism‐based structure that involves a two‐dimensional array of rings and a three‐dimensional array of double‐rings, with short fixed rods and long sliding rods attached at the outer and inner surfaces of the rings, respectively. Based on the theory of thin rings, effective Poisson's ratio and effective coefficient of thermal expansion (CTE) models have been obtained for single‐ring structures, pole‐loaded double‐ring structures, and equator‐loaded double‐ring structures. Results establish a very strong correlation between these effective properties with the ring radius and rod lengths. In addition, the analysis of four of the double‐ring structures reveals that the sign of Poisson's ratio is dependent on the direction of loading. An example application is demonstrated herein in which positive thermal expansion rings, used in conjunction with rigid rods, enable the design of an overall zero thermal expansion structure (i.e., minimal thermal stress) with tunable negative thermal expansion internal microstructure for use as sieve. Finally, it is herein shown that, by judicious positioning of the short fixed rods and/or long sliding rods, one may possibly obtain various combinations of positive and negative CTEs with positive and negative Poisson's ratio.