Programmed shape-morphing into complex target shapes using architected dielectric elastomer actuators

Dielectric elastomer actuators (DEAs) are among the fastest and most energy-efficient, shape-morphing materials. To date, their shapes have been controlled using patterned electrodes or stiffening elements. While their actuated shapes can be analyzed for prescribed configurations of electrodes or stiffening elements (the forward problem), the design of DEAs that morph into target shapes (the inverse problem) has not been fully addressed. Here, we report a simple analytical solution for the inverse design and fabrication of programmable shape-morphing DEAs. To realize the target shape, two mechanisms are combined to locally control the actuation magnitude and direction by patterning the number of local active layers and stiff rings of varying shapes, respectively. Our combined design and fabrication strategy enables the creation of complex DEA architectures that shape-morph into simple target shapes, for instance, those with zero, positive, and negative Gaussian curvatures as well as complex shapes, such as a face.

Programming Cellular Alignment in Engineered Cardiac Tissue via Bioprinting Anisotropic Organ Building Blocks

The ability to replicate the 3D myocardial architecture found in human hearts is a grand challenge. Here, the fabrication of aligned cardiac tissues via bioprinting anisotropic organ building blocks (aOBBs) composed of human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) is reported. A bioink composed of contractile cardiac aOBBs is first generated and aligned cardiac tissue sheets with linear, spiral, and chevron features are printed. Next, aligned cardiac macrofilaments are printed, whose contractile force and conduction velocity increase over time and exceed the performance of spheroid-based cardiac tissues. Finally, the ability to spatially control the magnitude and direction of contractile force by printing cardiac sheets with different aOBB alignment is highlighted. This research opens new avenues to generating functional cardiac tissue with high cell density and complex cellular alignment.

Characterization of avoidable hospital admissions in patients with lung cancer in the immunotherapy and targeted therapy era

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Background: Hospitalization is the second largest contributor of cancer care spending, and over 50% of lung cancer patients are admitted to the hospital while receiving treatment. Patients who avoid hospital admission have reduced health care costs with a higher quality of life. This is the first study that characterizes the risk factors and outcomes for avoidable hospital admissions of lung cancer patients. It is the first to examine the extent to which hospitalizations from immunotherapy and targeted therapy could be avoided. Methods: A retrospective chart review of lung cancer patients admitted January 2018 through December 2018 was conducted. Demographics, disease and treatment history, admission characteristics, outcomes, and end-of-life care utilization were recorded. Following a multidisciplinary consensus review, hospitalizations were determined “avoidable” or “unavoidable.” Generalized estimating equation logistic regression models analyzed risks and outcomes associated with avoidable admissions. Kaplan-Meier estimators examined the median overall survival (mOS) between patients with and without avoidable admissions. Results: We evaluated 319 admissions from 188 patients with a median age of 66 and 16%/84% SCLC/NSCLC. Cancer-related symptoms accounted for 66% of hospitalizations; pneumonia and other infections comprised 34%, and 32% were due to cancer-related pain, vomiting, or failure to thrive (FTT). Common causes of unavoidable hospitalizations were unexpected disease progression causing symptoms, COPD exacerbation, and infection. Of the 47 hospitalizations identified as avoidable (15%), the mOS was 1.6 months; the mOS of unavoidable hospitalizations was 9.7 months (HR 2.07; 95% CI 1.34-3.19; p < 0.001). Significant reasons for avoidable admissions included cancer-related pain (p = 0.021), hypervolemia (p = 0.033), patient desire to initiate hospice services (p = 0.011), and errors in medication reconciliation or distribution (p < 0.001). Errors in medication management caused 26% of the avoidable hospitalizations. Of admissions in patients on immunotherapy (n = 102) or targeted therapy (n = 44), 9% were due to adverse effects of treatment. Patients on immunotherapy and targeted therapy were not more likely to have avoidable hospitalizations compared to patients not on the treatments (p = 0.323 and 0.133, respectively). Patients with avoidable admissions were 3.02 times more likely to enroll in hospice within 30 days of hospitalization compared to unavoidable admissions (95% CI 1.54-5.92; p = 0.001). Conclusions: Patients on immunotherapy or targeted therapy were only rarely admitted due to side effects of treatment. Hospitalizations may be avoided with more aggressive outpatient symptom management, earlier hospice discussion with at-risk patients, and outpatient pharmacist review of medications following hospital discharge.

Biomanufacturing human tissues via organ building blocks

The construction of human organs on demand remains a tantalizing vision to solve the organ donor shortage. Yet, engineering tissues that recapitulate the cellular and architectural complexity of native organs is a grand challenge. The use of organ building blocks (OBBs) composed of multicellular spheroids, organoids, and assembloids offers an important pathway for creating organ-specific tissues with the desired cellular-to-tissue-level organization. Here, we review the differentiation, maturation, and 3D assembly of OBBs into functional human tissues and, ultimately, organs for therapeutic repair and replacement. We also highlight future challenges and areas of opportunity for this nascent field.

Biomimetic and Biologically Compliant Soft Architectures via 3D and 4D Assembly Methods: A Perspective

Recent progress in soft material chemistry and enabling methods of 3D and 4D fabrication-emerging programmable material designs and associated assembly methods for the construction of complex functional structures-is highlighted. The underlying advances in this science allow the creation of soft material architectures with properties and shapes that programmably vary with time. The ability to control composition from the molecular to the macroscale is highlighted-most notably through examples that focus on biomimetic and biologically compliant soft materials. Such advances, when coupled with the ability to program material structure and properties across multiple scales via microfabrication, 3D printing, or other assembly techniques, give rise to responsive (4D) architectures. The challenges and prospects for progress in this emerging field in terms of its capacities for integrating chemistry, form, and function are described in the context of exemplary soft material systems demonstrating important but heretofore difficult-to-realize biomimetic and biologically compliant behaviors.

Orthogonally induced differentiation of stem cells for the programmatic patterning of vascularized organoids and bioprinted tissues

The generation of organoids and tissues with programmable cellular complexity, architecture and function would benefit from the simultaneous differentiation of human induced pluripotent stem cells (hiPSCs) into divergent cell types. Yet differentiation protocols for the overexpression of specific transcription factors typically produce a single cell type. Here we show that patterned organoids and bioprinted tissues with controlled composition and organization can be generated by simultaneously co-differentiating hiPSCs into distinct cell types via the forced overexpression of transcription factors, independently of culture-media composition. Specifically, we used such orthogonally induced differentiation to generate endothelial cells and neurons from hiPSCs in a one-pot system containing either neural or endothelial stem-cell-specifying media, and to produce vascularized and patterned cortical organoids within days by aggregating inducible-transcription-factor and wild-type hiPSCs into randomly pooled or multicore-shell embryoid bodies. Moreover, by leveraging multimaterial bioprinting of hiPSC inks without extracellular matrix, we generated patterned neural tissues with layered regions composed of neural stem cells, endothelium and neurons. Orthogonally induced differentiation of stem cells may facilitate the fabrication of engineered tissues for biomedical applications.

Photoswitchable Covalent Adaptive Networks Based on Thiol-Ene Elastomers

Covalent adaptive networks combine the advantages of cross-linked elastomers and dynamic bonding in a single system. In this work, we demonstrate a simple one-pot method to prepare thiol-ene elastomers that exhibit reversible photoinduced switching from an elastomeric gel to fluid state. This behavior can be generalized to thiol-ene cross-linked elastomers composed of different backbone chemistries (e.g., polydimethylsiloxane, polyethylene glycol, and polyurethane) and vinyl groups (e.g., allyl, vinyl ether, and acrylate). Photoswitching from the gel to fluid state occurs in seconds upon exposure to UV light and can be repeated over at least 180 cycles. These thiol-ene elastomers also exhibit the ability to heal, remold, and serve as reversible adhesives.

Association of Rurality With Annual Repeat Lung Cancer Screening in the Veterans Health Administration

PURPOSE

Lung cancer causes the largest number of cancer-related deaths in the United States. Lung cancer incidence rates, mortality rates, and rates of advanced stage disease are higher among those who live in rural areas. Known disparities in lung cancer outcomes between rural and nonrural populations may be in part because of barriers faced by rural populations. The authors tested the hypothesis that among Veterans who receive initial lung cancer screening, rural Veterans would be less likely to complete annual repeat screening than nonrural Veterans.

METHODS

A retrospective cohort study was conducted of 10 Veterans Affairs medical centers from 2015 to 2019. Rural and nonrural Veterans undergoing lung cancer screening were identified. Rural status was defined using the rural-urban commuting area codes. The primary outcome was annual repeat lung cancer screening in the 9- to 15-month window (primary analysis) and 31-day to 18-month window (sensitivity analysis) after the first documented lung cancer screening. To examine rurality as a predictor of annual repeat lung cancer screening, multivariable logistic regression models were used.

RESULTS

In the final analytic sample of 11,402 Veterans, annual repeat lung cancer screening occurred in 27.7% of rural Veterans (641 of 2,316) and 31.8% of nonrural Veterans (2,891 of 9,086) (adjusted odds ratio: 0.86; 95% confidence interval: 0.73-1.03). Similar results were seen in the sensitivity analysis, with 41.6% of rural Veterans (963 of 2,316) versus 45.2% of nonrural Veterans (4,110 of 9,086) (adjusted odds ratio: 0.88; 95% confidence interval: 0.73-1.04) having annual repeat screening in the expanded 31-day to 18-month window.

CONCLUSIONS

Among a national cohort of Veterans, rural residence was associated with numerically lower odds of annual repeat lung cancer screening than nonrural residence. Continued, intentional outreach efforts to increase annual repeat lung cancer screening among rural Veterans may offer an opportunity to decrease deaths from lung cancer.

Innervated, Self-Sensing Liquid Crystal Elastomer Actuators with Closed Loop Control

The programmable assembly of innervated LCE actuators (iLCEs) with prescribed contractile actuation, self-sensing, and closed loop control via core-shell 3D printing is reported. This extrusion-based direct ink writing method enables coaxial filamentary features composed of pure LM core surrounded by an LCE shell, whose director is aligned along the print path. Specifically, the thermal response of the iLCE fiber-type actuators is programmed, measured, and modeled during Joule heating, including quantifying the concomitant changes in fiber length and resistance that arise during simultaneous heating and self-sensing. Due to their reversible, high-energy actuation and their resistive feedback, it is also demonstrated that iLCEs can be regulated with closed loop control even when perturbed with large bias loads. Finally, iLCE architectures capable of programmed, self-sensing 3D shape change with closed loop control are fabricated.

Organizational Readiness for Lung Cancer Screening: A Cross-Sectional Evaluation at a Veterans Affairs Medical Center

OBJECTIVES

Lung cancer has the highest cancer-related mortality in the United States and among Veterans. Screening of high-risk individuals with low-dose CT (LDCT) can improve survival through detection of early-stage lung cancer. Organizational factors that aid or impede implementation of this evidence-based practice in diverse populations are not well described. We evaluated organizational readiness for change and change valence (belief that change is beneficial and valuable) for implementation of LDCT screening.

METHODS

We performed a cross-sectional survey of providers, staff, and administrators in radiology and primary care at a single Veterans Affairs Medical Center. Survey measures included Shea's validated Organizational Readiness for Implementing Change (ORIC) scale and Shea's 10 items to assess change valence. ORIC and change valence were scored on a scale from 1 to 7 (higher scores representing higher readiness for change or valence). Multivariable linear regressions were conducted to determine predictors of ORIC and change valence.

RESULTS

Of 523 employees contacted, 282 completed survey items (53.9% overall response rate). Higher ORIC scores were associated with radiology versus primary care (mean 5.48, SD 1.42 versus 5.07, SD 1.22, β = 0.37, P = .039). Self-identified leaders in lung cancer screening had both higher ORIC (5.56, SD 1.39 versus 5.11, SD 1.26, β = 0.43, P = .050) and change valence scores (5.89, SD 1.21 versus 5.36, SD 1.19, β = 0.51, P = .012).

DISCUSSION

Radiology health professionals have higher levels of readiness for change for implementation of LDCT screening than those in primary care. Understanding health professionals' behavioral determinants for change can inform future lung cancer screening implementation strategies.

Protocol to evaluate an enterprise-wide initiative to increase access to lung cancer screening in the Veterans Health Administration

INTRODUCTION

The Veterans Affairs Partnership to increase Access to Lung Screening (VA-PALS) is an enterprise-wide initiative to implement lung cancer screening programs at VA medical centers (VAMCs). VA-PALS will be using implementation strategies that include program navigators to coordinate screening activities, trainings for navigators and radiologists, an open-source software management system, tools to standardize low-dose computed tomography image quality, and access to a support network. VAMCs can utilize strategies according to their local needs. In this protocol, we describe the planned program evaluation for the initial 10 VAMCs participating in VA-PALS.

MATERIALS AND METHODS

The implementation of programs will be evaluated using the Consolidated Framework for Implementation Research to ensure broad contextual guidance. Program evaluation measures have been developed using the Reach, Effectiveness, Adoption, Implementation and Maintenance framework. Adaptations of screening processes will be assessed using the Framework for Reporting Adaptations and Modifications to Evidence Based Interventions. Measures collected will reflect the inner settings, estimate and describe the population reached, adoption by providers, implementation of the programs, report clinical outcomes and maintenance of programs. Analyses will include descriptive statistics and regression to evaluate predictors and assess implementation over time.

DISCUSSION

This theory-based protocol will evaluate the implementation of lung cancer screening programs across the Veterans Health Administration using scientific frameworks. The findings will inform plans to expand the VA-PALS initiative beyond the original sites and can guide implementation of lung cancer screening programs more broadly.

Hierarchically Porous Ceramics via Direct Writing of Binary Colloidal Gel Foams

Hierarchically porous ceramics with a high specific surface area and interconnected porosity may find potential application as particulate filters, catalyst supports, and battery electrodes. We report the design and programmable assembly of cellular ceramic architectures with controlled pore size, volume, and interconnectivity across multiple length scales via direct foam writing. Specifically, binary colloidal gel foams are created that contain entrained bubbles stabilized by the irreversible adsorption of attractive alumina and carbon (porogen) particles at their air-water interfaces. Composition effects on foam ink rheology and printing behavior are investigated. Sintered ceramic foams exhibited specific permeabilities that increased from 2 × 10^-13 to 1 × 10^-12 m² and compressive strengths that decreased from 40 to 1 MPa, respectively, with increasing specific interfacial area. Using direct foam writing, 3D ceramic lattices composed of open-cell foam struts were fabricated with tailored mechanical properties and interconnected porosity across multiple length scales.

Evidence-based smoking cessation treatment: a comparison by healthcare system

BACKGROUND

A systems-level approach to smoking cessation treatment may optimize healthcare provider adherence to guidelines. Institutions such as the Veterans Health Administration (VHA) are unique in their systematic approach, but comparisons of provider behavior in different healthcare systems are limited.

METHODS

We surveyed general medicine providers and specialists in a large academic health center (AHC) and its affiliated VHA in the Mid-South in 2017 to determine the cross-sectional association of healthcare system in which the provider practiced (exposure: AHC versus VHA) with self-reported provision of evidence-based smoking cessation treatment (delivery of counseling plus smoking cessation medication or referral) at least once in the past 12 months (composite outcome). Multivariable logistic regression with adjustment for specialty was performed in 2017-2019.

RESULTS

Of 625 healthcare providers surveyed, 407 (65%) responded, and 366 (59%) were analyzed. Most respondents practiced at the AHC (273[75%] vs VHA 93[25%]) and were general internists (215[59%]); pulmonologists (39[11%]); hematologists/oncologists (69[19%]); and gynecologists (43[12%]). Most respondents (328[90%]) reported the primary outcome. The adjusted odds of evidence-based smoking cessation treatment were higher among VHA vs. AHC healthcare providers (aOR = 4.3; 95% CI 1.3-14.4; p = .02). Health systems differed by provision of individual treatment components, including smoking cessation medication use (98% VHA vs. 90% AHC, p = 0.02) and referral to smoking cessation services (91% VHA vs. 65% AHC p = 0.001).

CONCLUSIONS

VHA healthcare providers were significantly more likely to provide evidence-based smoking cessation treatment compared to AHC healthcare providers. Healthcare systems' prioritization of and investment in smoking cessation treatment is critical to improving providers' adherence to guidelines.

Low Provider Knowledge Is Associated With Less Evidence-Based Lung Cancer Screening

BACKGROUND

Despite widespread recommendation and supportive policies, screening with low-dose CT (LDCT) is incompletely implemented in the US healthcare system. Low provider knowledge of the lung cancer screening (LCS) guidelines represents a potential barrier to implementation. Therefore, we tested the hypothesis that low provider knowledge of guidelines is associated with less provider-reported screening with LDCT.

PATIENTS AND METHODS

A cross-sectional survey was performed in a large academic medical center and affiliated Veterans Health Administration in the Mid-South United States that comprises hospital and community-based practices. Participants included general medicine providers and specialists who treat patients aged >50 years. The primary exposure was LCS guideline knowledge (US Preventive Services Task Force/Centers for Medicare & Medicaid Services). High knowledge was defined as identifying 3 major screening eligibility criteria (55 years as initial age of screening eligibility, smoking status as current or former smoker, and smoking history of ≥30 pack-years), and low knowledge was defined as not identifying these 3 criteria. The primary outcome was self-reported LDCT order/referral within the past year, and the secondary outcome was screening chest radiograph. Multivariable logistic regression evaluated the adjusted odds ratio (aOR) of screening by knowledge.

RESULTS

Of 625 providers recruited, 407 (65%) responded, and 378 (60.5%) were analyzed. Overall, 233 providers (62%) demonstrated low LCS knowledge, and 224 (59%) reported ordering/referring for LDCT. The aOR of ordering/referring LDCT was less among providers with low knowledge (0.41; 95% CI, 0.24-0.71) than among those with high knowledge. More providers with low knowledge reported ordering screening chest radiographs (aOR, 2.7; 95% CI, 1.4-5.0) within the past year.

CONCLUSIONS

Referring provider knowledge of LCS guidelines is low and directly proportional to the ordering rate for LDCT in an at-risk US population. Strategies to advance evidence-based LCS should incorporate provider education and system-level interventions to address gaps in provider knowledge.

National Lung Cancer Screening Utilization Trends in the Veterans Health Administration

Background

Many Veterans are high risk for lung cancer. Low-dose computed tomography (LDCT) is an effective strategy for lung cancer early detection in a high-risk population. Our objective was to describe and compare annual and geographic utilization trends for LDCT screening in the Veteran's Health Administration (VHA).

Methods

A national retrospective cohort of screened Veterans from January 1, 2011 to May 31, 2018 was used to calculate annual and regional rates of initial LDCT utilization per 1000 eligible Veterans. We identified Veterans with a first LDCT exam using common procedure terminology codes G0297 or 71250 and described as "lung cancer screening," "screening," or "LCS." The number of screen-eligible Veterans per year was calculated as unique Veterans aged 55 to 80 years seen at a Veterans Affairs medical center (VAMC) in that year, multiplied by 32% (estimated proportion with eligible smoking history). We present 95% confidence intervals (CI) for rates.

Results

Screened Veterans had a mean age of 66.1 years (standard deviation [SD] = 5.6); 95.5% male; 77.4% Caucasian. There were 119 300 LDCT exams, of which 80 819 (67.7%) were initial. Nationally, initial screens increased from 0 (95% CI = 0.00 to 0.00) in 2011 to 29.6 (95% CI = 29.26 to 29.88) scans per 1000 eligible Veterans in 2018 (P_trend < .001). Initial screens increased over time within all geographic regions, most prominently in northeastern and Florida VAMCs.

Conclusion

VHA LDCT utilization increased from 2011 to 2018. However, overall utilization remained low. Future interventions are needed to increase lung cancer screening utilization among eligible Veterans.

Effect of luminal flow on doming of mpkCCD cells in a 3D perfusable kidney cortical collecting duct model

The cortical collecting duct (CCD) of the mammalian kidney plays a major role in the maintenance of total body electrolyte, acid/base, and fluid homeostasis by tubular reabsorption and excretion. The mammalian CCD is heterogeneous, composed of Na⁺-absorbing principal cells (PCs) and acid-base-transporting intercalated cells (ICs). Perturbations in luminal flow rate alter hydrodynamic forces to which these cells in the cylindrical tubules are exposed. However, most studies of tubular ion transport have been performed in cell monolayers grown on or epithelial sheets affixed to a flat support, since analysis of transepithelial transport in native tubules by in vitro microperfusion requires considerable expertise. Here, we report on the generation and characterization of an in vitro, perfusable three-dimensional kidney CCD model (3D CCD), in which immortalized mouse PC-like mpkCCD cells are seeded within a cylindrical channel embedded within an engineered extracellular matrix and subjected to luminal fluid flow. We find that a tight epithelial barrier composed of differentiated and polarized PCs forms within 1 wk. Immunofluorescence microscopy reveals the apical epithelial Na⁺ channel ENaC and basolateral Na⁺/K⁺-ATPase. On cessation of luminal flow, benzamil-inhibitable cell doming is observed within these 3D CCDs consistent with the presence of ENaC-mediated Na⁺ absorption. Our 3D CCD provides a geometrically and microphysiologically relevant platform for studying the development and physiology of renal tubule segments.

3D Printable and Reconfigurable Liquid Crystal Elastomers with Light-Induced Shape Memory via Dynamic Bond Exchange

3D printable and reconfigurable liquid crystal elastomers (LCEs) that reversibly shape-morph when cycled above and below their nematic-to-isotropic transition temperature (T_NI ) are created, whose actuated shape can be locked-in via high-temperature UV exposure. By synthesizing LCE-based inks with light-triggerable dynamic bonds, printing can be harnessed to locally program their director alignment and UV light can be used to enable controlled network reconfiguration without requiring an imposed mechanical field. Using this integrated approach, 3D LCEs are constructed in both monolithic and heterogenous layouts that exhibit complex shape changes, and whose transformed shapes could be locked-in on demand.

Voxelated soft matter via multimaterial multinozzle 3D printing

There is growing interest in voxelated matter that is designed and fabricated voxel by voxel^1-4. Currently, inkjet-based three-dimensional (3D) printing is the only widely adopted method that is capable of creating 3D voxelated materials with high precision^1-4, but the physics of droplet formation requires the use of low-viscosity inks to ensure successful printing⁵. By contrast, direct ink writing, an extrusion-based 3D printing method, is capable of patterning a much broader range of materials^6-13. However, it is difficult to generate multimaterial voxelated matter by extruding monolithic cylindrical filaments in a layer-by-layer manner. Here we report the design and fabrication of voxelated soft matter using multimaterial multinozzle 3D (MM3D) printing, in which the composition, function and structure of the materials are programmed at the voxel scale. Our MM3D printheads exploit the diode-like behaviour that arises when multiple viscoelastic materials converge at a junction to enable seamless, high-frequency switching between up to eight different materials to create voxels with a volume approaching that of the nozzle diameter cubed. As exemplars, we fabricate a Miura origami pattern¹⁴ and a millipede-like soft robot that locomotes by co-printing multiple epoxy and silicone elastomer inks of stiffness varying by several orders of magnitude. Our method substantially broadens the palette of voxelated materials that can be designed and manufactured in complex motifs.

Architected Polymer Foams via Direct Bubble Writing

Polymer foams are cellular solids composed of solid and gas phases, whose mechanical, thermal, and acoustic properties are determined by the composition, volume fraction, and connectivity of both phases. A new high-throughput additive manufacturing method, referred to as direct bubble writing, for creating polymer foams with locally programmed bubble size, volume fraction, and connectivity is reported. Direct bubble writing relies on rapid generation and patterning of liquid shell-gas core droplets produced using a core-shell nozzle. The printed polymer foams are able to retain their overall shape, since the outer shell of these bubble droplets consist of a low-viscosity monomer that is rapidly polymerized during the printing process. The transition between open- and closed-cell foams is independently controlled by the gas used, while the foam can be tailored on-the-fly by adjusting the gas pressure used to produce the bubble droplets. As exemplars, homogeneous and graded polymer foams in several motifs, including 3D lattices, shells, and out-of-plane pillars are fabricated. Conductive composite foams with controlled stiffness for use as soft pressure sensors are also produced.

Association of a Lung Screening Program Coordinator With Adherence to Annual CT Lung Screening at a Large Academic Institution

BACKGROUND

Detection of early-stage lung cancer improves during subsequent rounds of screening with low-dose CT and potentially leads to saving lives with curative treatment. Therefore, adherence to annual lung screening is important. We hypothesized that adherence to annual screening would increase after hiring of a dedicated program coordinator.

METHODS

We performed a mixed-methods study in a retrospective cohort of patients who underwent lung screening at our academic institution between January 1, 2014, and March 31, 2018. Patients with baseline lung screening examinations performed between January 1, 2014, and September 30, 2016, with Lung CT Screening Reporting & Data System 1 or 2 scores and a 12-month follow-up recommendation were included. We tracked patient adherence to annual follow-up lung screening over time (before and after hiring of a program coordinator) and conducted a cross-sectional survey of patients nonadherent to annual follow-up to elicit quantitative and qualitative feedback.

RESULTS

Of the 319 patients who completed baseline lung screening with normal results, 189 (59%) were adherent to annual follow-up recommendations and 130 (41%) were nonadherent. Patient adherence varied over time: 21.7% adherence (10 of 46) before hiring a program coordinator and 65.6% adherence (179 of 273) after the program coordinator's hire date. Patients reported the following reasons for nonadherence to annual lung screening: lack of transportation, financial cost, lack of communication by physicians, and lack of current symptoms.

CONCLUSIONS

Adherence to annual lung screening after normal baseline studies increased significantly over time. Hiring a full-time program coordinator was likely associated with this increased in adherence.

Biomanufacturing of organ-specific tissues with high cellular density and embedded vascular channels

Engineering organ-specific tissues for therapeutic applications is a grand challenge, requiring the fabrication and maintenance of densely cellular constructs composed of ~10⁸ cells/ml. Organ building blocks (OBBs) composed of patient-specific-induced pluripotent stem cell-derived organoids offer a pathway to achieving tissues with the requisite cellular density, microarchitecture, and function. However, to date, scant attention has been devoted to their assembly into 3D tissue constructs. Here, we report a biomanufacturing method for assembling hundreds of thousands of these OBBs into living matrices with high cellular density into which perfusable vascular channels are introduced via embedded three-dimensional bioprinting. The OBB matrices exhibit the desired self-healing, viscoplastic behavior required for sacrificial writing into functional tissue (SWIFT). As an exemplar, we created a perfusable cardiac tissue that fuses and beats synchronously over a 7-day period. Our SWIFT biomanufacturing method enables the rapid assembly of perfusable patient- and organ-specific tissues at therapeutic scales.

Untethered soft robotic matter with passive control of shape morphing and propulsion

There is growing interest in creating untethered soft robotic matter that can repeatedly shape-morph and self-propel in response to external stimuli. Toward this goal, we printed soft robotic matter composed of liquid crystal elastomer (LCE) bilayers with orthogonal director alignment and different nematic-to-isotropic transition temperatures (T _NI) to form active hinges that interconnect polymeric tiles. When heated above their respective actuation temperatures, the printed LCE hinges exhibit a large, reversible bending response. Their actuation response is programmed by varying their chemistry and printed architecture. Through an integrated design and additive manufacturing approach, we created passively controlled, untethered soft robotic matter that adopts task-specific configurations on demand, including a self-twisting origami polyhedron that exhibits three stable configurations and a "rollbot" that assembles into a pentagonal prism and self-rolls in programmed responses to thermal stimuli.

National lung cancer screening utilization trends in the Veterans Health Administration

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Background: Low-dose CT (LDCT) is an effective means for early lung cancer detection, but is often underutilized. An estimated 900,000 Veterans are eligible for lung cancer screening. We are the first to describe national lung cancer screening utilization trends in the Veterans Health Administration (VHA). Methods: We assembled a retrospective cohort of patients within the VHA’s Observational Medical Outcomes Partnership (OMOP) Common Data Model who underwent lung cancer screening. LDCT scans with Common Procedure Terminology (CPT) codes G0297 or 71250 from January 1, 2011 to May 31, 2018 were eligible for inclusion. We further selected exams described as “lung cancer screening,” “screening,” or “LCS.” We used descriptive statistics with frequencies and medians to calculate the total exams per Veteran and evaluate utilization trends over time and by region. Results: At initial screening, Veterans had a median age of 66 (IQR 61, 70), 95% were male, 76% Caucasian. From January 1, 2011 to May 31, 2018, 75 VHA facilities performed 129,363 LDCT exams for lung cancer screening; 87,950 (68%) initial and 41,413 (32%) subsequent exams. Screening has increased over time (226 in 2011-2012; 7848 in 2013-2014; 41,225 in 2015-2016; 80,064 in 2017 until May 31, 2018) in all regions. Providers in primary care/internal medicine (56%), family medicine (16%), pulmonology (6%), oncology (0.3%), other specialties (21%) ordered screening exams. Conclusions: Lung cancer screening with low-dose CT within the VHA increased over time within all geographic regions. Future strategies aimed at the Veteran, provider, and healthcare system levels are needed to increase lung cancer screening utilization among eligible Veterans. [Table: see text]

Perovskite nanowire-block copolymer composites with digitally programmable polarization anisotropy

One-dimensional (1D) nanomaterials with highly anisotropic optoelectronic properties are key components in energy harvesting, flexible electronics, and biomedical imaging devices. 3D patterning methods that precisely assemble nanowires with locally controlled composition and orientation would enable new optoelectronic device designs. As an exemplar, we have created and 3D-printed nanocomposite inks composed of brightly emitting colloidal cesium lead halide perovskite (CsPbX₃, X = Cl, Br, and I) nanowires suspended in a polystyrene-polyisoprene-polystyrene block copolymer matrix. The nanowire alignment is defined by the programmed print path, resulting in optical nanocomposites that exhibit highly polarized absorption and emission properties. Several devices have been produced to highlight the versatility of this method, including optical storage, encryption, sensing, and full-color displays.