Incremental Advancement Research Articles

Comparison between twin block appliance and mandibular advancement on clear aligners in the improvement of airway dimension: incremental versus maximum bite advancement.

The aim of the present retrospective study was to compare the changes resulting from treatment using the MA and the TB with special regard to the oro-and naso-pharyngeal sagittal airway dimensions in subjects with dentoskeletal Class II malocclusions and positive history of Sleep Disorder Breathing (SDB) diagnosed through the Pediatric Sleep Questionnaire (PSQ). This retrospective study involved 2 groups of subjects: patients treated with Twin Block (TB group: n = 22, 10 males, 12 females; mean age 12.0 ± 1.3 years) and patients treated with Mandibular Advancement (MA group: n = 23, 11 males, 12 females; mean age 12.2 ± 1.1 years). Pretreatment (T1) and posttreatment (T2) lateral cephalograms were analyzed. All patients underwent the PSQ to diagnose SDB. In both treated groups there was an increase in the airways dimensions and an improvement in symptoms related SDB. The statistical comparison of the changes between T1 and T2 in the TB group showed a significant increment in upper airway size (PNS-AD2, +1.50 mm + -3.30; McNamara's upper pharynx dimension, +2.21 + -4.21) after active treatment. The MA group showed similar results during active treatment with a significant increase in both upper (PNS-AD2, +2.72 + -2.65; McNamara's upper pharynx dimension, +2.97 + -3.07) and lower (PNS-AD1, +2.17 mm + -3.54) airway size. Despite the different structure of these two devices and the different advancement protocols, both appliances were valuable as a suitable treatment option for Class II patients with respiratory disorders, inducing an increase of upper and lower airway size and a significant reduction in diurnal symptoms.

Comparative analysis of efficacy and safety of ChAdOx1 nCov-19 and AD26.COV2.S

Vaccine technology has been going through some radical and incremental advancement over the years for its importance as the most crucial tool in the prevention and elimination of transmissive diseases. Since the outbreak of COVID-19, several vaccine platforms were being studied, developed, and entered the market. Among the platforms, vector viral vaccines attracted particular attention for the cooperation of viral vectors to deliver genetic material of the pathogens. While the mechanism has improved the flexibility of vaccine design and efficacy, the adverse events after vaccination were worth attention at the same time. Taking ChAdOx12 nCov-19 and AD26.COV2.S. as the subjects, the efficacy and safety of the two vaccine platforms were compared and analyzed. In this paper, the initial vaccine efficacy, the resistances against virus variants, and various post vaccination adverse events were looked in more detail to identify the different factors that could affect the performance of viral vector vaccines.

Strain-Based elevation monitoring during construction of the Salesforce Tower

Anticipated complexities associated with monitoring elevation changes during construction of the 326 m tall Salesforce Tower in San Francisco prompted the implementation of a strain-based system. This system utilizes strain gages embedded into the tower’s reinforced concrete walls and the resulting measurements are inputs into one of three shortening estimation models of varying complexity and applicability. This methodology was successfully utilized to monitor time dependent shortening due to axial, shrinkage, and creep strains in the tower. Strain-gage based systems assist with slender tower construction in urban areas because the tower’s slenderness coupled with adjacent obstacles stretch the limits of traditional or alternative instrument capabilities and they provide redundancy of measurement to ensure accuracy. This paper is a case study of how a strain-based elevation monitoring system helped this project to be successful. The most relevant findings are: 1) the shortening estimation models were in agreement with conventional survey measurements (±4.6 mm) within their recommended tower height and temperature range capabilities; 2) implementation of this system resulted in a net monitoring cost reduction on the order of 15 %, 400 less labor hours, and reduced potential for project delays; and 3) improvements are needed for supplying power to the sensors as there were interruptions, cut cables, and lack of sources that led to a 44 % sensor success rate. Given the need for structural health monitoring, the successful outcomes documented in this paper, and the potential for continued improvement by way of, for example, wireless and battery free sensing technologies, the work documented herein is believed to be an incremental advancement to the state-of-the-art of tall buildings.

Delocalized Lithium Ion Flux by Solid-State Electrolyte Composites Coupled with 3D Porous Nanostructures for Highly Stable Lithium Metal Batteries.

This work investigates the root cause of failure with the ultimate anode, Li metal, when employing conventional/composite separators and/or porous anodes. Then a feasible route of utilizing Li metal is presented. Our operando and microscopy studies have unveiled that Li+ flux passing through the conventional separator is not uniform, resulting in preferential Li plating/stripping. Porous anodes alone are subject to clogging with moderate- or high-loading cathodes. Here we discovered it is necessary to seek synergy from our separator and anode pair to deliver delocalized Li+ to the anode and then uniformly plate Li metal over the large surface areas of the porous anode. Our polymer composite separator containing a solid-state electrolyte (SE) can provide numerous Li+ passages through the percolated SE and pore networks. Our finite element analysis and comparative tests disclosed the synergy between the homogeneous Li+ flux and current density reduction on the anode. Our composite separators have induced compact and uniform Li plating with robust inorganic-rich solid electrolyte interphase layers. The porous anode decreased the nucleation overpotential and interfacial contact impedance during Li plating. Full cell tests with LiFePO4 and Li[Ni0.8Mn0.1Co0.1]O2 (NMC811) exhibited remarkable cycling behaviors: ∼80% capacity retention at the 750th and 235th cycle, respectively. A high-loading NMC811 (4 mAh cm-2) full cell displayed maximum cell-level energy densities of 334 Wh kg-1 and 783 Wh L-1. This work proposes a solution for raising energy density by adopting Li metal, which could be a viable option considering only incremental advancement in conventional cathodes lately.

Invisalign treatment with mandibular advancement: A retrospective cohort cephalometric appraisal.

ObjectiveTo examine the skeletal, dental, and soft-tissue cephalometric effects of class II correction using Invisalign’s mandibular advancement feature in growing patients.Materials and MethodsA retrospective cohort clinical study was performed on cases that were started between 2017 and 2019. A total of 32 patients (13 females, 19 males), with an average age of 13 years old (9.9-14.8 years) had undergone Invisalign treatment (Align Technology, Inc., San Jose, CA) wherein the mandibular advancement phase was completed were included. Photos, digital study models, and cephalograms were taken once during the patients’ initial visit and again upon completing the mandibular advancement phase of treatment. The number of aligners worn and the time of treatment in months was recorded for each subject. Cephalometric analysis was performed and overjet and overbite were measured. Statistical analysis was performed using SPSS statistical software (version 25; SPSS, Chicago, Ill) and the level of significance was set at P <0.05. Descriptive statistics were performed to generate means and differences for each cephalometric measurement as well as patient data including age, treatment time, and aligner number. Differences between measurements from patients before treatment (T1) and after treatment (T2) with the mandibular advancement feature were evaluated using a paired t -test.ResultsAll 32 patients had multiple jumps staged for the precision wings, i.e., incremental advancement. The average length of treatment for the MA phase was 9.2 months (7.5-13.8 months) and the average number of aligners used during this time was 37 (30-55). Statistically significant differences between T1 and T2, in favor of class II correction, were observed in the ANB angle, WITS appraisal, facial convexity, and mandibular length. The nasolabial angle, overjet, and overbite also showed statistically significant changes between T1 and T2.ConclusionInvisalign aligners with the mandibular advancement feature took approximately 9 months for 1.5 mm of overjet correction. The lower incisor angulation was maintained during class II correction. The minimal skeletal changes are in favor of class II correction.

Target SARS-CoV-2: theoretical exploration on clinical suitability of certain drugs

We propose a unique theoretical methodology because of the global high priority rating to search for the repurposed drugs that outfit clinical suitability to SARS-CoV-2. The approach is based on the exploration of structural analysis, computation of biothermodynamics, interactions and the prediction of entropy sign successively via molecular dynamics. We tested this methodology for Favipiravir/Dolutegravir drugs on the apo form of SARS-CoV-2 main protease. This theoretical exploration not only suggested the presence of strong interactions between (SARS-CoV-2 + Favipiravir/Dolutegravir) but also emphasized the clinical suitability of Favipiravir over Dolutegravir to treat SARS-CoV-2 main protease. The supremacy of Favipiravir over Doultegravir is well supported by the results of global clinical trials on SARS-CoV-2 infection. Thus, this work will pave the way for incremental advancement towards future design and development of more specific inhibitors to treat SARS-CoV-2 infection in humans. Communicated by Ramaswamy H. Sarma

Target SARS-CoV-2: computation of binding energies with drugs of dexamethasone/umifenovir by molecular dynamics using OPLS-AA force field

IntroductionIn recent times, myriads of public have been infected with a novel SARS-CoV-2, and the fatality toll has reached thousands and been mounting step by step, which is a major crisis in the world. The challenge for this burning issue pertinent to repurposed medicines which prevent novel coronavirus is of immense concern for all scientists around the globe until the arrival of the vaccine.MethodsBecause of the global high priority rating on the search for the repurposed drugs which outfits clinical suitability to SARS-CoV-2, a unique theoretical methodology is proposed. The approach is based on explorations of biothermodynamics computed via molecular dynamics, root-mean-square deviation (RMSD), radius of gyration (Rg) and interactions. This unique methodology is tested for umifenovir/dexamethasone drugs on (SARS-CoV-2) main protease.ResultsThis theoretical exploration not only suggested the presence of strong interactions between (SARS-CoV-2 + umifenovir/dexamethasone) but also emphasized the clinical suitability of dexamethasone over umifenovir to treat SARS-CoV-2. This supremacy of dexamethasone is well supported by the results of global clinical trials and COVID-19 therapeutic approved management guidelines of countries.ConclusionsThus, this work will pave a way for incremental advancement towards future design and development of more specific inhibitors for the treatment of SARS-CoV-2 infection in humans.

Secular trends in the incidence and survival of all leukemia types in the United States from 1975 to 2017.

Background: Various studies have indicated that the prognosis of leukemia has been improved in recent years, but the secular trends of incidence and long-term survival of all leukemia have not been thoroughly examined.Methods: We estimated the leukemia incidence and 5-year survival rate along with the temporal trends by sex, race, age, and subtype in the United States over the past four decades using Surveillance, Epidemiology, and End Results (SEER) database.Results: The overall incidence of leukemia steadily increased from 12.39/100 000 in 1975 to 14.65/100 000 in 2011, and then began to decline in recent years (13.73/100 000 in 2017), with average annual percent changes (APC) of 0.350 (P<0.001). The 5-year relative survival rate of leukemia patients significantly improved from 33.2% in 1975 to 66.1% in 2012 (APC=1.980, P<0.001). The main subtypes of leukemia, including acute lymphoblastic leukemia, acute myeloid leukemia, chronic lymphocytic leukemia, and chronic myeloid leukemia, increased in most age groups; conversely, the incidences of all other subtypes were gradually declined during the monitoring period. The incremental advancement in leukemia prognosis had been achieved in almost all histological subtypes, especially among young patients.Conclusions: Based on SEER data, the leukemia incidence increased gradually over the past decades, and then began to decline in recent years in the United States. The 5-year relative survival rate increased incrementally over time, especially among young patients. However, the huge disparities among different sexes, races, histological subtypes, and age groups, emphasize that precise causes control and innovative treatments need to be developed to reduce the incidence and improve the prognosis, especially among specific populations.

Chaos or coherence? Future directions for moral education

ABSTRACT This introduction attempts to draw together the various threads which comprise this special issue and place them in the context of recent disruptions to the political order occasioned by the rise of populist politics, the resurgence of widespread racial tensions in a number of polities and the emergence of a global pandemic. Central to the challenges thrown up by these ‘events’ and a motive force, has been the incremental advancement of libertarianism with its capacity to disorient and displace a more socially oriented liberalism. Together with a range of changes (some might argue enhancements) to our technological capacities these moves offer significant challenges to the advancement of a moral education that is sufficiently robust. The discussion moves from the development of historico-political readings of our present situation and challenge, through some important epistemic questions about truth-telling, integrity and sociality, and on to practical questions about the relationship between technology and personal moral capacities. This last challenge is explored with respect to the need to maintain the very analogue capacity of judgement in the face of a digitally mediated world. Moreover, this introduction also explores the structural and political challenges posed by narrow specialisation in the field of moral education, the evolution of bio-technology/materials and consciousness.

Direct Transmittance Estimation in Heterogeneous Participating Media Using Approximated Taylor Expansions.

Evaluating the transmittance between two points along a ray is a key component in solving the light transport through heterogeneous participating media and entails computing an intractable exponential of the integrated medium's extinction coefficient. While algorithms for estimating this transmittance exist, there is a lack of theoretical knowledge about their behaviour, which also prevent new theoretically sound algorithms from being developed. For this purpose, we introduce a new class of unbiased transmittance estimators based on random sampling or truncation of a Taylor expansion of the exponential function. In contrast to classical tracking algorithms, these estimators are non-analogous to the physical light transport process and directly sample the underlying extinction function without performing incremental advancement. We present several versions of the new class of estimators, based on either importance sampling or Russian roulette to provide finite unbiased estimators of the infinite Taylor series expansion. We also show that the well known ratio tracking algorithm can be seen as a special case of the new class of estimators. Lastly, we conduct performance evaluations on both the central processing unit (CPU) and the graphics processing unit (GPU), and the results demonstrate that the new algorithms outperform traditional algorithms for heterogeneous mediums.

A lifetime assessment and prediction method for large area solder joints

Mechanical bending fatigue experiments were conducted on large area Pb-rich and SnSb-based model solder joints consisting of Cu-strip/solder/DCB substrates. Experimental lifetime curves in the range between 105 and 108 loading cycles at room and elevated temperature showed an improved fatigue resistance for SnSb alloys. Crack length as a function of loading cycles (da/dN) was determined for selected samples to study the cyclic degradation behaviour of the solder layer. Crack initiation and propagation in the joints was modelled on the basis of a damage accumulation rule considering the strain rate and temperature dependency of the solder alloy. Application of the FEM model to large area solder joints allowed calculation of the incremental advancement of the crack front, determination of the crack growth rate (da/dN) and prediction of lifetime under a given loading condition.

Molecular, genomic and mutational landscape of oral leukoplakia.

Oral leukoplakia (OLK) and its more aggressive clinical variant proliferative verrucous leukoplakia (PVL) remain enigmatic disorders clinically and histopathologically. Despite decades of research into both, there has been only incremental advancement in our understanding of their aetiology and pathogenesis and only minimal improvement in effective management strategies. Currently, no specific prognostic genetic or molecular marker has been reported for leukoplakia. There is, however, an emerging body of evidence characterising the genomic and transcriptomic profile of OLK. Regardless of the significance of cellular and architectural features of OLK and PVL, it is clear from studies reported in this review that new emerging evidence points to the presence of premalignant molecular subtypes of leukoplakia which require further investigation. This up-to-date review explores the contemporary genomic, transcriptomic and mutational landscape of leukoplakia broadly, discusses concepts that may not be widely recognised or accepted and purposefully highlights studies with juxtaposed findings in an effort to challenge dogma. It also highlights the urgent need for a concerted international effort of original collaborative research which will only occur by pooling collective efforts, resources and intellect to define the molecular fingerprint of this enigmatic disorder, in the hope it will better inform diagnosis, stratification and treatment.

Does the Technique for Assessing Loss of Resistance Alter the Magnitude of Epidural Needle Tip Overshoot?

Postdural puncture headache due to accidental dural puncture is a consequence of excessive needle tip overshoot distance after entering the epidural space via a loss of resistance (LOR) technique. We are not aware of any quantitative comparison of the magnitude of needle tip overshoot (distance traveled by the needle tip beyond the point where LOR can be discerned) for the various LOR assessment techniques that are taught. Such a comparison may provide insight into contributing factors of accidental dural puncture and associated postdural puncture headache. A custom-built simulator was used to evaluate the following 3 LOR assessment techniques: incremental needle advancement, intermittent LOR assessment (II); continuous needle advancement, high-frequency intermittent LOR assessment (CI); and continuous needle advancement, continuous LOR assessment (CC). There were significant mean differences in maximum overshoot past a virtual LOR plane due to technique (F(2,124) = 79.31, P < 0.001) (Fig. 2). Specifically, maximum overshoot was greater with technique II [mean = 3.8 mm, 95% confidence interval (CI) = 3.4-4.3] versus either CC (mean = 1.9 mm, 95% CI = 1.5-1.8, P < 0.001) or CI (mean = 1.4 mm, 95% CI = 0.9-2.3, P < 0.001). Differences in maximum overshoot between CC and CI were not statistically different (P = 0.996). Maximum overshoot was greater at 4 cm (mean = 3.0 mm, 95% CI = 2.6-3.4) compared with 5 cm (mean = 2.3 mm, 95% CI = 2.0-2.5, P = 0.044), 6 cm (mean = 2.0 mm, 95% CI = 1.9-2.2, P = 0.054), 7 cm (mean = 1.9 mm, 95% CI = 1.7-2.1, P = 0.002), and 8 cm (mean = 1.8 mm, 95% CI = 1.6-2.1, P = 0.001). In addition, maximum overshoot at 5 cm was greater than that at 7 cm (P = 0.020) and 8 cm (P = 0.037). The other LOR depths were not statistically significantly different from each other. Depth did not have a significant interaction with technique (P = 0.517). Technique preference had neither a significant relationship to maximum overshoot (P = 0.588) nor a significant interaction with LOR assessment technique (P = 0.689). Technique II LOR assessment produced the greatest needle overshoot past the simulated LOR plane after obtaining LOR. This was consistent across all LOR depths. In this bench study, the II technique resulted in the deepest needle tip maximum overshoot. We are in the process of designing a clinical study to collect similar data in patients.

Incremental or maximal mandibular advancement in the treatment of class II malocclusion through functional appliances: A systematic review with meta-analysis.

To systematically review the effects of functional appliances (FA) using incremental vs maximal mandibular advancement regarding cephalometric measurements in class II malocclusion individuals and to assess patient-centred-outcomes. Six electronic databases were searched without restrictions up to April 2020. We included randomized and non-randomized controlled trials using identical FA. Trials involving participants who used adjunct appliances, inter-maxillary elastics, who received surgical treatment or that recruited individuals with cleft lip/palate or craniofacial deformity/syndrome were excluded. Risks of bias assessments were performed using the Cochrane risk of bias tool-2 and ROBINS-I tools. Mean differences (MD) with their 95% confidence intervals were calculated from random-effects meta-analyses. The GRADE tool was used to assess the certainty of the evidence. Six studies were included. Low to very low certainty of evidence indicated that incremental mandibular advancement resulted in greater gains in mandibular length (MD=0.89 [0.38, 1.34], P=.0005), anterior mandibular displacement (MD=0.73 [0.40, 1.06], P<.0001) and SNB angle (MD=0.44 [0.02, 0.85], P=.04). No significant differences were found for maxillary, dento-alveolar and upper airway outcomes between construction bite protocols (P>.05). Study design and appliance-related factors influenced the results of the subgroup analyses. Existing evidence is inadequate to assess patient-related response and long-term outcome could not be assessed. Currently, there are a heterogeneous number of studies with low quality and methodological issues can lead to biases that strongly limit an evidence-based conclusion. Weak evidence suggests gains in mandibular skeletal parameters in the short term using FA with incremental mandibular advancement. Randomized trials evaluating key topics such as patient-centred outcomes need to be conducted to guide clinical management. PROSPERO (CRD42019147436).

Top classic articles to read for elbow training

Articles written during the development of a particular field lay the foundation for that field’s incremental advancement. Some are more cited than others; however, each contains formative principles that drive the field forward and change modern day practices. This article reviews a number of these articles that the author believes are important in the education of residents on an upper extremity rotation.

Incremental Maxillomandibular Advancement: The Relationship Between Skeletal Advancement and Airway Volume

IntroductionObstructive sleep apnea (OSA) is characterized by repetitive episodes of supra‐laryngeal airway collapse during sleep, causing increased airflow resistance and reduced respiration. Obstruction and reduced volume mainly occurs in the retropalatal (RPS) and/or retroglossal space (RGS). The most effective surgical treatment (save tracheostomy) is maxillomandibular advancement (MMA). During MMA, the skeletal framework is modified, thereby reducing airway collapse upon inspiration. A clear mechanistic understanding of MMA surgery describing airway dimensions and resulting volumetric increases does not yet exist. The primary objective of the study was to define volume changes during incremental MMA. The secondary objective was to measure where maximal airway tissue movement occurs.MethodsAn oral surgeon performed MMA on three fresh cadaveric heads (n=3). The mandible and maxilla were advanced by four implanted distraction devices (KLS Martin Inc.). The devices were bilaterally advanced by 2mm increments to 14mm to encompass the full range of clinical advancements. Computerized tomography (CT) scans, (0.6 mm isotropic, Siemens, O‐arm), were taken at baseline (no advancement) and each advancement level (2, 4, 6, 8, 10, 12, 14mm). For the primary objective, total airway volume and linear anteroposterior (AP) and lateral (LAT) 2D dimensions of the RPS and RGS were analyzed at each incremental advancement using Amira™ (Thermo Fisher Scientific). To address the secondary objective, translation of airway tissues, radiopaque microbeads (800 μm, Ortech) were implanted at borders of the RPS and RGS using a syringe and endoscope and their movement was tracked through each advancement.ResultsDuring incremental MMA, airway volume increased at each increment compared to baseline. For 0–2, 2–4 &amp; 4–6mm, normalized volume increases were incrementally larger with each advancement [mean0–2mm = 20.3 ± 22.8%; mean2–4mm = 34.9 ± 13.8%; mean4–6mm = 62.4 ± 17.2%]. Consistent volumetric increases occurred during the advancements from 6mm to 10mm [mean6–8mm = 50.8 ± 27.0%; mean8–10mm = 45.6 ± 28.7%]. Preliminary analysis (n=1) shows that during early MMA (2mm–6mm), lateral dimensions increased at a greater magnitude compared to later advancements (8–14mm). Microbead migration supports these findings while highlighting airway wall movement.ConclusionWhile volumetric increases occur at each advancement, the greatest relative change occurs at the advancement from 4–6mm. Relative volumetric increases show a consistent increase in airway volume with each incremental advancement throughout 6–10mm. Lateral wall widening is the chief mechanism for early volume change, at advancements between 2–6mm, while AP dimensions are affected at 8–14mm advancements. The relationships between 2D (AP/LAT) changes and 3D (volume) demonstrate that volume change in initial advancements are primarily due to lateral enlargement. Depending on OSA severity, clinicians may exploit these relationships when performing MMA.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The effects of gratitude on suicidal ideation among late adolescence: A mediational chain

This study examined both the mediation effects of basic psychological needs and depression on the relationship between gratitude and suicidal ideation in late adolescence. Two hundred and eighty-seven Taiwanese university students completed measures of gratitude, basic psychological needs, depressive symptoms, and suicidal ideation. A cross-sectional design was conducted in the present study. Path analyses indicated that basic psychological needs and depression acted as full mediators of the association between gratitude and suicidal ideation. The identified model revealed a significant and sequential mediational path from gratitude through basic psychological needs, depression, and suicidal ideation. The current work is an incremental advancement in understanding the complex relationship between selected resiliency and risk factors of suicidal thinking.

Development and analysis of DAYANI arc contour intelligent technique for navigation of two-wheeled mobile robot

Purpose This paper aims to generate an obstacle free real time optimal path in a cluttered environment for a two-wheeled mobile robot (TWMR). Design/methodology/approach This TWMR resembles an inverted pendulum having an intermediate body mounted on a robotic mobile platform with two wheels driven by two DC motors separately. In this article, a novel motion planning strategy named as DAYANI arc contour intelligent technique has been proposed for navigation of the two-wheeled self-balancing robot in a global environment populated by obstacles. The developed new path planning algorithm evaluates the best next feasible point of motion considering five weight functions from an arc contour depending upon five separate navigational parameters. Findings Authenticity of the proposed navigational algorithm has been demonstrated by computing the path length and time taken through a series of simulations and experimental verifications and the average percentage of error is found to be about 6%. Practical implications This robot dynamically stabilizes itself with taller configuration, can spin on the spot and rove along through obstacles with smaller footprints. This diversifies its areas of application to both indoor and outdoor environments especially with very narrow spaces, sharp turns and inclined surfaces where its multi-wheel counterparts feel difficult to perform. Originality/value A new obstacle avoidance and path planning algorithm through incremental step advancement by evaluating the best next feasible point of motion has been established and verified through both experiment and simulation.

Analogies across auxetic models based on deformation mechanism (Phys. Status Solidi RRL 6/2017)

In his Review @ RRL (article no. 1600440), Teik-Cheng Lim establishes analogies across auxetic models by identifying mechanism similarities. On the cover, the identification of auxetic mechanism analogy from four models is shown: the rotating square model (top left), anti-tetrachiral model (top right), a type of missing rib model (bottom left), and re-entrant model (bottom right). One quadrant from each auxetic model, consisting of four rotating elements, is transposed onto corresponding quadrants in the other auxetic models to show the analogous counterparts. Likewise, the color-coded circles or linkages in the top right quadrants indicate the corresponding joints. The mechanism analogy across different auxetic models reveals that it is the mechanism comparability, rather than geometrical resemblance, that takes precedence in establishing fundamental similarities across various auxetic models. Consequently, any newly introduced auxetic model would be classified as being of only incremental advancement, even if it exhibits novelty in geometrical microstructure, as long as its deformation mechanism is well-established. The demonstration of a new deformation mechanism would be required to justify the classification of any introduced auxetic model as being fundamentally novel.

Cryoballoon ablation of persistent atrial fibrillation: feasibility and safety of left atrial roof ablation with generation of conduction block in addition to antral pulmonary vein isolation.

Although the generation of linear lesions by ablation improves success rates in patients with persistent atrial fibrillation (AF), the procedure has been considered unsuitable for cryoablation balloon catheter technologies. We developed a technique for linear ablations, using second-generation cryoballoon technology. This was a single-arm, prospective study in 76 patients with persistent AF treated consecutively at our centre. Cryoablation was performed using a 28 mm second-generation cryoballoon. The first cryoenergy application was performed in close proximity to the position during isolation of the left superior pulmonary vein (PV). Sequential overlapping freezes were applied along the left atrial (LA) roof by slight clockwise rotation of the sheath in combination with slight retraction of the sheath and incremental advancement of the cryoballoon, until reaching the original position for right superior PV isolation. The acute endpoint was the creation of a roofline, defined as complete conduction block across the LA roof >120 ms and ascending activation across the posterior LA wall. Acute success in roofline generation was achieved in 88% of patients, applying on average five (median 4-6) freezes with nadir temperature of -40°C (-36 to -44°C). In five patients, conduction block could not be achieved. No phrenic nerve injuries occurred during roofline generation. Generation of linear roofline lesions is possible with the second-generation cryoballoon. The technique can be used in combination with PV isolation to treat persistent AF with good acute success rates, short procedure times, and acceptable safety concerns. If validated by further studies, the method would be an appealing alternative to radiofrequency ablation techniques.