Moiré effect enables versatile design of topological defects in nematic liquid crystals.

Recent advances in surface-patterning techniques of liquid crystals have enabled the precise creation of topological defects, which promise a variety of emergent applications. However, the manipulation and application of these defects remain limited. Here, we harness the moiré effect to engineer topological defects in patterned nematic liquid crystal cells. Specifically, we combine simulation and experiment to examine a nematic cell confined between two substrates of periodic surface anchoring patterns; by rotating one surface against the other, we observe a rich variety of highly tunable, novel topological defects. These defects are shown to guide the three-dimensional self-assembly of colloids, which can conversely impact defects by preventing the self-annihilation of loop-defects through jamming. Finally, we demonstrate that certain nematic moiré cells can engender arbitrary shapes represented by defect regions. As such, the proposed simple twist method enables the design and tuning of mesoscopic structures in liquid crystals, facilitating applications including defect-directed self-assembly, material transport, micro-reactors, photonic devices, and anti-counterfeiting materials.

Experimental demonstration of deterministic quantum search for multiple marked states without adjusting the oracle.

Grover's search algorithm is a well-known quantum algorithm that has been extensively studied and improved to increase its success rate and enhance its flexibility. However, most improved search algorithms require an adjustment of the oracle, which may not be feasible in practical problem-solving scenarios. In this work, we report an experimental demonstration of a deterministic quantum search for multiple marked states without adjusting the oracle. A linear optical setup is designed to search for two marked states, one in a 16-state database with an initial equal-superposition state and the other in an 8-state database with different initial nonequal-superposition states. The evolution of the probability of finding each state in the database is also measured and displayed. Our experimental results agree well with the theoretical predictions, thereby proving the feasibility of the search protocol and the implementation scheme. This work is a pioneering experimental demonstration of deterministic quantum search for multiple marked states without adjusting the oracle.

A 3D-Printed Ferromagnetic Liquid Crystal Elastomer with Programmed Dual-Anisotropy and Multi-Responsiveness.

Liquid crystal elastomers (LCE) and magnetic soft materials are promising active materials in many emerging fields, such as soft robotics. Despite the high demand for developing active materials that combine the advantages of LCE and magnetic actuation, the lack of independent programming of the LCE nematic order and magnetization in a single material still hinders the desired multi-responsiveness. In this study, a ferromagnetic LCE (magLCE) ink with nematic order and magnetization is developed that can be independently programmed to be anisotropic, referred to as "dual anisotropy", via a customized 3D-printing platform. The magLCE ink is fabricated by dispersing ferromagnetic microparticles in the LCE matrix, and a 3D-printing platform is created by integrating a magnet with 3-DoF motion into an extrusion-based 3D printer. In addition to magnetic fields, magLCEs can also be actuated by heating sources (either environmental heating or photo-heating of the embedded ferromagnetic microparticles) with a high energy density and tunable actuation temperature. A programmed magLCE strip robot is demonstrated with enhanced adaptability to complex environments (different terrains, magnetic fields, and temperatures) using a multi-actuation strategy. The magLCE also has potential applications in mechanical memory, as demonstrated by the multistable mechanical metastructure array with remote writability and stable memory.

Collective transport and reconfigurable assembly of nematic colloids by light-driven cooperative molecular reorientations.

Nanomotors in nature have inspired scientists to design synthetic molecular motors to drive the motion of microscale objects by cooperative action. Light-driven molecular motors have been synthesized, but using their cooperative reorganization to control the collective transport of colloids and to realize the reconfiguration of colloidal assembly remains a challenge. In this work, topological vortices are imprinted in the monolayers of azobenzene molecules which further interface with nematic liquid crystals (LCs). The light-driven cooperative reorientations of the azobenzene molecules induce the collective motion of LC molecules and thus the spatiotemporal evolutions of the nematic disclination networks which are defined by the controlled patterns of vortices. Continuum simulations provide physical insight into the morphology change of the disclination networks. When microcolloids are dispersed in the LC medium, the colloidal assembly is not only transported and reconfigured by the collective change of the disclination lines but also controlled by the elastic energy landscape defined by the predesigned orientational patterns. The collective transport and reconfiguration of colloidal assemblies can also be programmed by manipulating the irradiated polarization. This work opens opportunities to design programmable colloidal machines and smart composite materials.

Collective vortical motion and vorticity reversals of self-propelled particles on circularly patterned substrates.

The collective behavior of self-propelled particles (SPPs) under the combined effects of a circularly patterned substrate and circular confinement is investigated through coarse-grained molecular dynamics simulations of polarized and disjoint ring polymers. The study is performed over a wide range of values of the SPPs packing fraction ϕ[over ¯], motility force F_{D}, and area fraction of the patterned region. At low packing fractions, the SPPs are excluded from the system's center and exhibit a vortical motion that is dominated by the substrate at intermediate values of F_{D}. This exclusion zone is due to the coupling between the driving force and torque induced by the substrate, which induces an outward spiral motion of the SPPs. For high values of F_{D}, the SPPs exclusion from the center is dominated by the confining boundary. At high values of ϕ[over ¯], the substrate pattern leads to reversals in the vorticity, which become quasiperiodic with increasing ϕ[over ¯]. We also found that the substrate pattern is able to separate SPPs based on their motilities.

Improved mineralization of dental enamel by electrokinetic delivery of F- and Ca2+ ions.

This in vitro study evaluated the effects of the infiltration of F- and Ca2+ ions into human enamel by electrokinetic flow (EKF) on the enamel microhardness and F- content. Sound human enamel ground sections of unerupted third molars were infiltrated with de-ionized water by EKF and with F- ion by EKF respectively. All samples were submitted to two successive transverse acid-etch biopsies (etching times of 30 s and 20 min) to quantify F- ion infiltrated deep into enamel. Remarkably, sound enamel showed a large increase in microhardness (MH) after infiltration of NaF (p < 0.00001) and CaCl2 (p = 0.013) by EKF. Additionally, NaF-EKF increased the remineralization in the lesion body of artificial enamel caries lesions compared to controls (p < 0.01). With the enamel biopsy technique, at both etching times, more F- ions were found in the EKF-treated group than the control group (p << 0.05), and more fluoride was extracted from deeper biopsies in the NaF-EKF group. In conclusion, our results show that EKF treatment is superior in transporting Ca2+ and F- ions into sound enamel when compared to molecular diffusion, enhancing both the mineralization of sound enamel and the remineralization of artificial enamel caries.

Shape Morphing by Topological Patterns and Profiles in Laser-Cut Liquid Crystal Elastomer Kirigami.

Programming shape changes in soft materials requires precise control of the directionality and magnitude of their mechanical response. Among ordered soft materials, liquid crystal elastomers (LCEs) exhibit remarkable and programmable shape shifting when their molecular order changes. In this work, we synthesized, remotely programmed, and modeled reversible and complex morphing in monolithic LCE kirigami encoded with predesigned topological patterns in its microstructure. We obtained a rich variety of out-of-plane shape transformations, including auxetic structures and undulating morphologies, by combining different topological microstructures and kirigami geometries. The spatiotemporal shape-shifting behaviors are well recapitulated by elastodynamics simulations, revealing that the complex shape changes arise from integrating the custom-cut geometry with local director profiles defined by topological defects inscribed in the material. Different functionalities, such as a bioinspired fluttering butterfly, a flower bud, dual-rotation light mills, and dual-mode locomotion, are further realized. Our proposed LCE kirigami with topological patterns opens opportunities for the future development of multifunctional devices for soft robotics, flexible electronics, and biomedicine.

Effects of resilience on impulsivity, cognition and depression during protracted withdrawal among Chinese male methamphetamine users.

BACKGROUND: Methamphetamine (METH) dependence is a complex and dynamic public health problem. Long-term abuse of METH can increase numerous risks of mental and physical problems. Currently, the methods to reduce METH dependence and improve the withdrawal symptoms are limited and ineffective. Resilience is seen as a multidimensional and dynamic capability to recover or bounce back from stressful events and is also generally considered as a protective factor against mental dysfunction. METHODS: One hundred thirty-four males with METH dependence were consecutively recruited from Huanglong Compulsory Isolated Detoxification Center between 2019 and 2021, of whom 112 were into the group. The Connor-Davidson Resilience Scale (CD-RISC), Self-rating depression scale (SDS), Self-rating anxiety scale (SAS), Barratt Impulsiveness Scale-11(BIS-11), and the Repeatable Battery for the Assessment of Neuropsychological Status (Rbans) were used to evaluate resilience, depression, anxiety, impulsivity, and cognition respectively. RESULTS: The results mainly indicated that high resilience group showed lower SDS, SAS and BIS-11 scores than low resilience group (all p < 0.05). Besides, the total scores of Rbans were higher in high resilience groups than low resilience group (both p < 0.05). Moreover, linear regression results showed that resilience may be influenced by the scores of SDS and SAS. CONCLUSIONS: Resilience is negatively correlated with impulsivity and depression. Besides, it is also positively associated with cognitive function. Drug users with higher resilience may have a strong ability to mobilize psychological resources to create a good psychological environment, which may have a positive effect on the relief or improvement of symptoms.

Active transformations of topological structures in light-driven nematic disclination networks.

SignificanceTopological defects are marvels of nature. Understanding their structures is important for their applications in, for example, directed self-assembly, sensing, and photonic devices. There is recent interest in active motion and transformation of topological defects in active nematics. In these nonequilibrium systems, however, the motion and transformation of disclinations are difficult to control, thereby hindering their applications. Here, we propose a surface-patterned system engendering periodic three-dimensional disclinations, which can be excited by light irradiation and undergo a programmable transformation between different topological states. Continuum simulations recapitulating these topological structures characterize the bending, breaking, and relinking events of the disclinations during the nonequilibrium process. Our work provides an alternative dynamic system in which active transformation of topological defects can be engineered.

Re-referring Children for Multidisciplinary Obesity Management.

OBJECTIVES: To examine characteristics of children referred for obesity management based on referral frequency, child- and referrer-related variables associated with re-referral, and determine whether re-referral increased treatment initiation. STUDY DESIGN: This population-level, retrospective analysis included all 2- to 17-year-olds referred for obesity management to 1 of 3 multidisciplinary clinics in Alberta, Canada between April 2013 and December 2017. Children were dichotomized based on referral frequency, specifically once only or more than once (re-referred). Data were retrieved from standardized referral forms and patient registries. Analyses included logistic regression and generalized estimating equations models. RESULT: We analyzed data from 2745 children (47.2% female; mean age: 11.4 years; mean body mass index z score: 3.03) and 2705 physicians (60.2% female; 65.6% pediatricians). Overall, 300 (10.2%) children were re-referred with most (n = 276; 92.0%) being referred twice. Children were less likely to be re-referred if they were referred by a family physician (vs pediatrician) (aOR 0.62; 95% CI 0.46-0.84; P = .0018) or scheduled a clinic appointment following their index referral (aOR: 0.29; 95% CI 0.21-0.4; P < .001). Treatment initiation was higher in children who were referred once only (42.1%) vs their re-referred peers (18.0%; P < .0001); however, for children who were re-referred, they were more likely to initiate treatment following their second referral (aOR 2.3; 95% CI 1.22-4.31; P = .01). This improvement was not sustained on subsequent referrals (aOR 0.44; 95% CI 0.17-1.12; P = .08). CONCLUSIONS: Few children were re-referred for pediatric obesity management; however, for those children who were re-referred, being re-referred once only increased the likelihood of treatment initiation.

Collective motion of cells modeled as ring polymers.

In this article, we use a coarse-grained model of disjoint semi-flexible ring polymers to investigate computationally the spatiotemporal collective behavior of cell colonies. A ring polymer in this model is self-propelled by a motility force along the cell's polarity, which depends on its historical kinetics. Despite the repulsive interaction between the cells, a collective behavior sets in as a result of cells pushing against each other. This cooperative motion emerges as the amplitude of the motility force is increased and/or their areal density is increased. The degree of collectivity, characterized by the average cluster size, the velocity field order parameter, and the polarity field nematic order parameter, is found to increase with increasing the amplitude of the motility force and area coverage of the cells. Furthermore, the degree of alignment exhibited by the cell velocity field within a cluster is found to be stronger than that exhibited by the cell polarity. Comparison between the collective behavior of elongated cells and that of circular cells, at the same area coverage and motility force, shows that elongated cells exhibit a stronger collective behavior than circular cells, in agreement with earlier studies of self-propelled anisotropic particles. An investigation of two-cell collisions shows that while two clustered cells move in tandem, their polarities are misaligned. As such the cells push against each other while moving coherently.

Nematic Templated Complex Nanofiber Structures by Projection Display.

Oriented arrays of nanofibers are ubiquitous in nature and have been widely used in recreation of the biological functions such as bone and muscle tissue regenerations. However, it remains a challenge to produce nanofiber arrays with a complex organization by using current fabrication techniques such as electrospinning and extrusion. In this work, we propose a method to fabricate the complex organization of nanofiber structures templated by a spatially varying ordered liquid crystal host, which follows the pattern produced by a maskless projection display system. By programming the synchronization of the rotated polarizer and projected segments with different shapes, various configurations of nanofiber organization ranging from a single to two-dimensional lattice of arbitrary topological defects are created in a deterministic manner. The nanofiber arrays can effectively guide and promote neurite outgrowth. The application of nanofibers with arced profiles and topological defects on neural tissue organization is also demonstrated. This finding, combined with the versatility and programmability of nanofiber structures, suggests that they will help solve challenges in nerve repair, neural regeneration, and other related tissue engineering fields.

Light-Actuated Liquid Crystal Elastomer Prepared by Projection Display.

Soft materials with programmability have been widely used in drug delivery, tissue engineering, artificial muscles, biosensors, and related biomedical engineering applications. Liquid crystal elastomers (LCEs) can easily morph into three-dimensional (3D) shapes by external stimuli such as light, heat, and humidity. In order to program two-dimensional (2D) LCE sheets into desired 3D morphologies, it is critical to precisely control the molecular orientations in LCE. In this work, we propose a simple photopatterning method based on a maskless projection display system to create spatially varying molecular orientations in LCE films. By designing different synchronized rotations of the polarizer and projected images, diverse configurations ranging from individual to 2D lattice of topological defects are fabricated. The proposed technique significantly simplified the photopatterning procedure without using fabricated masks or waveplates. Shape transformations such as a cone and a truncated square pyramid, and functionality mimicking the responsive Mimosa Pudica are demonstrated in the fabricated LCE films. The programmable LCE morphing behaviors demonstrated in this work will open opportunities in soft robotics and smart functional devices.

Physician-related predictors of referral for multidisciplinary paediatric obesity management: a population-based study.

BACKGROUND: It is recommended that primary care-based physicians refer children with overweight and obesity to multidisciplinary paediatric obesity management, which can help to improve weight and health. OBJECTIVE: To determine predictors of referral to multidisciplinary paediatric obesity management. METHODS: This retrospective, population-level study included physicians who could refer 2-17 years old with a body mass index ≥85th percentile to one of three multidisciplinary paediatric obesity management clinics in Alberta, Canada. Physician demographic and procedural data were obtained from Practitioner Claims and Provider Registry maintained by Alberta Health from January 2014 to December 2017. Physician characteristics were compared based on whether they did or did not refer children for obesity management. Univariable and multivariable logistic regression models analysed associations between physician characteristics and referral making. RESULTS: Of the 3863 physicians (3468 family physicians, 395 paediatricians; 56% male; 49.3 ± 12.2 years old; 22.3 ± 12.6 years since graduation) practicing during the study period, 1358 (35.2%) referred at least one child for multidisciplinary paediatric obesity management. Multivariable regression revealed that female physicians (versus males) [odds ratio (OR): 1.68, 95% confidence interval (CI): 1.46-1.93; P < 0.0001], paediatricians (versus family physicians) (OR: 4.89, 95% CI: 3.85-6.21; P < 0.0001) and urban-based physicians (versus non-urban-based physicians) (OR: 2.17, 95% CI: 1.79-2.65; P < 0.0001) were more likely to refer children for multidisciplinary paediatric obesity management. CONCLUSIONS: Approximately one-third of family physicians and paediatricians referred children for multidisciplinary paediatric obesity management. Strategies are needed to improve referral practices for managing paediatric obesity, especially among male physicians, family physicians and non-urban-based physicians as they were less likely to refer children.

Paediatric overweight and obesity impact one-third of children in Canada and the USA. It is recommended that physicians refer children with overweight and obesity to paediatric obesity management, which can help to improve their weight and health. While referral practices of US physicians have been well characterized, Canadian evidence remains limited. To address this gap, we examined predictors of referral making for paediatric obesity management. Our study included physicians (family physicians and paediatricians) who could refer 2­17 years old with overweight and obesity to three paediatric weight management clinics in Alberta, Canada between January 2014 and December 2017. Descriptive analyses and regression models were performed. Of the 3863 physicians practicing during the study period, 1358 (35.2%) referred at least one child for paediatric obesity management. Referring physicians were more likely to be female, paediatricians and practicing in urban-based clinics. Additional research is needed to explore physicians' decisions to refer children for obesity management, which can inform interventions to enhance referral, and ultimately, improve the health and well-being of children with obesity.

Public health nurse referrals for paediatric weight management: A nested mixed-methods study.

AIMS AND OBJECTIVES: To (a) characterise and determine proportions of referred and enrolled children and (b) explore public health nurses' (PHNs) experiences, perspectives and recommendations regarding a new nurse-led referral pathway for paediatric weight management. BACKGROUND: Children with obesity and their families in Canada access specialised services for obesity management through physician referral. Since this requirement can prevent timely access to health services, we established and tested a referral pathway whereby PHNs directly refer children to specialised care for obesity management. DESIGN: Nested mixed-methods study reported using GRAMMS. METHOD: Our research study included children (2-17 years of age; body mass index ≥85th percentile) referred by a PHN to the Pediatric Centre for Weight and Health (PCWH; Stollery Children's Hospital, Edmonton, Alberta, Canada) from April 2017-September 2018. We summarised referral and enrolment data using descriptive statistics and conducted one-on-one, semi-structured telephone interviews with PHNs; interviews were audio-recorded, transcribed verbatim, managed using NVivo 12 and analysed by two independent reviewers using content analysis. RESULTS: Our sample included 79 referred children (4.4 ± 1.8 years old; 3.4 ± 1.3 BMI z-score; 52.7% male), of which 47 (59.5%) enrolled in care. PHNs' (n = 11) experiences, perspectives and recommendations regarding the new referral pathway were grouped into four categories: (a) practicality of the referral pathway (e.g., simple and straightforward), (b) utility of the referral pathway (e.g., economic and timesaving), (c) uptake of the referral pathway (e.g., physician's influence) and (d) recommendations to improve the referral pathway (e.g., having electronic access to the referral form). CONCLUSIONS: A PHN-specific referral pathway led most children and families to enrol in paediatric weight management and overall was perceived as acceptable and appropriate among PHNs. RELEVANCE TO CLINICAL PRACTICE: Our results highlight the valuable role that PHNs can play in directly referring children to specialised services for weight management. This pathway has the potential to reduce wait times and enhance treatment enrolment.

Controlled Dynamics of Neural Tumor Cells by Templated Liquid Crystalline Polymer Networks.

The ability to control the alignment and organization of cell populations has great potential for tissue engineering and regenerative medicine. A variety of approaches such as nano/microtopographical patterning, mechanical loading, and nanocomposite synthesis have been developed to engineer scaffolds able to control cellular properties and behaviors. In this work, a patterned liquid crystal polymer network (LCN) film is synthesized by using a nematic liquid crystal template in which the molecular orientations are predesigned by photopatterning technique. Various configurations of polymer networks such as linear and circular patterns are created. When neural tumor cells are plated onto the templated LCN films, the cell alignment, migration, and proliferation are directed in both linear and curvilinear fashions following the pattern of the aligned polymer chains. A complex LCN pattern with zigzag geometry is also fabricated and found to be capable of controlling cell alignment and collective cellular organization. The demonstrated control of cell dynamics and organization by LCN films with various molecular alignments opens new opportunities to design scaffolds to control cultured cell organization in a manner resembling that found in tissues and to develop novel advanced materials for nerve repair, tissue engineering, and regenerative medicine applications.

Self-Assembly of Aqueous Soft Matter Patterned by Liquid-Crystal Polymer Networks for Controlling the Dynamics of Bacteria.

The study of controlling the molecular self-assembly of aqueous soft matter is a fundamental scheme across multiple disciplines such as physics, chemistry, biology, and materials science. In this work, we use liquid-crystal polymer networks (LCNs) to control the superstructures of one aqueous soft material called lyotropic chromonic liquid crystals (LCLCs), which shows spontaneous orientational order by stacking the plank-like molecules into elongated aggregates. We synthesize a layer of patterned LCN films by a nematic liquid-crystal host in which the spatially varying molecular orientations are predesigned by plasmonic photopatterning. We demonstrate that the LCLC aggregates are oriented parallel to the polymer filaments of the LCN film. This patterned aqueous soft material shows immediate application for controlling the dynamics of swimming bacteria. The demonstrated control of the supramolecular assembly of aqueous soft matter by using a stimuli-responsive LCN film will find applications in designing dynamic advanced materials for bioengineering applications.

Enhanced teeth whitening by nanofluidic transport of hydrogen peroxide into enamel with electrokinetic flows.

Tooth whitening, a routine procedure in dentistry, is one of the examples of medical procedures that are limited by the challenge of delivering molecules into various types of nanoporous tissues. Current bleaching methods rely on simple diffusion of peroxides into enamel nano channels, therefore requires sufficient contact time with peroxides. In-office treatments often involve enamel etching or light activation which often results in patient sensitivity and potential soft tissue damage. OBJECTIVE: To demonstrate a robust method to transport hydrogen peroxide to greater depths into enamel nanopores through nanofluidic flows driven by electrokinetics, with the intention to increase efficacy while reducing treatment time. METHODS: Freshly extracted human teeth were subjected to electrokinetic flow treatment with hydrogen peroxide under different electric fields with varying operation times. Pre- and post-operative shade matching was done using a photospectrometer. RESULTS: It is demonstrated that the operation time for the same concentration of hydrogen peroxide can be shortened by 10 times. The proposed method showed significant improvements in whitening effects over control groups and thus offers promising clinically-viable chairside applications with efficacy. SIGNIFICANCE: The demonstrated nanofluidic transport of hydrogen peroxide into enamel has a potential to be applied for enhancing tooth whitening, compared to simple diffusion, without heating the hard dental tissues.

Liquid Crystals-Enabled AC Electrokinetics.

Phenomena of electrically driven fluid flows, known as electro-osmosis, and particle transport in a liquid electrolyte, known as electrophoresis, collectively form a subject of electrokinetics. Electrokinetics shows a great potential in microscopic manipulation of matter for various scientific and technological applications. Electrokinetics is usually studied for isotropic electrolytes. Recently it has been demonstrated that replacement of an isotropic electrolyte with an anisotropic, or liquid crystal (LC), electrolyte, brings about entirely new mechanisms of spatial charge formation and electrokinetic effects. This review presents the main features of liquid crystal-enabled electrokinetics (LCEK) rooted in the field-assisted separation of electric charges at deformations of the director that describes local molecular orientation of the LC. Since the electric field separates the charges and then drives the charges, the resulting electro-osmotic and electrophoretic velocities grow as the square of the applied electric field. We describe a number of related phenomena, such as alternating current (AC) LC-enabled electrophoresis of colloidal solid particles and fluid droplets in uniform and spatially-patterned LCs, swarming of colloids guided by photoactivated surface patterns, control of LCEK polarity through the material properties of the LC electrolyte, LCEK-assisted mixing at microscale, separation and sorting of small particles. LC-enabled electrokinetics brings a new dimension to our ability to manipulate dynamics of matter at small scales and holds a major promise for future technologies of microfluidics, pumping, mixing, sensing, and diagnostics.

Weight up? Changes in children's anthropometry from time of referral to baseline assessment for paediatric weight management.

OBJECTIVES: To examine children's wait time to access a multidisciplinary, tertiary-level weight management clinic and assess anthropometric changes from time of referral to baseline assessment. METHOD: A retrospective medical record review was completed of children (5 to 17 years) enrolled in a multidisciplinary, tertiary-level paediatric weight management clinic from 2006 to 2015. Children's demographic and anthropometric data from their referral to and baseline assessment at the clinic were retrieved from medical records. Based on changes in body mass index (BMI) z-score from the time of referral to baseline assessment, children were categorized as decreasers (>0.05 unit decrease), increasers (>0.05 unit increase) or stabilizers (-0.05 to 0.05 unit change). The proportion of children with a ≥0.25 unit BMI z-score reduction was calculated. Analysis of variance and chi-squared tests were performed. RESULTS: Children (n=400) were 11.7 ± 2.9 years old at the time of referral, 52.8% (n=211) female, and had an average wait time of 4.5 ± 3.9 months. By 3 and 6 months postreferral, 44.0% (n=176) and 80.8% (n=323), respectively, had attended baseline assessments. Based on BMI z-score change, children were classified as decreasers (n=183; 45.8%), increasers (n=118; 29.5%) or stabilizers (n=99; 24.8%). One-fifth of children (n=86; 21.5%) experienced a BMI z-score reduction ≥0.25 units, a subgroup that was younger, had a higher BMI z-score at referral, and had a longer wait time between referral and baseline assessment (all P<0.05). CONCLUSIONS: Most children who enrolled in paediatric weight management initiated treatment within six months and experienced a modest decrease or stabilization in BMI z-score during their wait time.