Twelve-month results of the ADAPT randomized controlled trial: Reproducibility and sustainability of advanced hybrid closed-loop therapy outcomes versus conventional therapy in adults with type 1 diabetes.

AIMS: To reassess the 6-month efficacy and to assess the 12-month sustained efficacy of the MiniMed™ 780G advanced hybrid closed-loop automated insulin delivery (AID) system compared to multiple daily injections plus intermittently scanned glucose monitoring (MDI+isCGM) in people with type 1 diabetes not meeting glucose targets. METHODS: The ADAPT study was a prospective, multicentre, open-label, randomized control trial in people with type 1 diabetes, with a glycated haemoglobin (HbA1c) concentration of at least 8.0% (64 mmol/mol), on MDI+isCGM therapy. After a 6-month study phase, participants randomized at baseline to MDI+isCGM switched to AID (SWITCH) while the others continued AID therapy (SUSTAIN) for an additional 6 months. The primary endpoint of this continuation phase was the within-group change in mean HbA1c between 6 and 12 months, with superiority in the SWITCH group and noninferiority in the SUSTAIN group (ClinicalTrials.gov: NCT04235504). RESULTS: A total of 39 SWITCH and 36 SUSTAIN participants entered the continuation phase. In the SWITCH group, HbA1c was significantly decreased by -1.4% (95% confidence interval [CI] -1.7% to -1.1%; P < 0.001) from a mean ± SD of 8.9% ± 0.8% (73.9 ± 8.6 mmol/mol) at 6 months to 7.5% ± 0.6% (58.5 ± 6.9 mmol/mol) at 12 months. Mean HbA1c increased by 0.1% (95% CI -0.05% to +0.25%), from 7.3% ± 0.6% (56.5 ± 6.7 mmol/mol) to 7.4% ± 0.8% (57.7 ± 9.1 mmol/mol) in the SUSTAIN group, meeting noninferiority criteria. Three severe hypoglycaemia events occurred in two SWITCH participants during the continuation phase. CONCLUSION: ADAPT study phase glycaemic improvements were reproduced and sustained in the continuation phase, supporting the early adoption of AID therapy in people with type 1 diabetes not meeting glucose targets on MDI therapy.

Advanced Hybrid Closed Loop in Adult Population With Type 1 Diabetes: A Substudy From the ADAPT Randomized Controlled Trial in Users of Real-Time Continuous Glucose Monitoring.

BACKGROUND: This analysis reports the findings from a predefined exploratory cohort (cohort B) from the ADAPT (ADvanced Hybrid Closed Loop Study in Adult Population with Type 1 Diabetes) study. Adults with type 1 diabetes (T1D) with suboptimal glucose control were randomly allocated to an advanced hybrid closed-loop (AHCL) system or multiple daily injections of insulin (MDI) plus real-time continuous glucose monitoring (RT-CGM). METHODS: In this prospective, multicenter, exploratory, open-label, randomized controlled trial, 13 participants using MDI + RT-CGM and with HbA1c ≥8.0% were randomized to switch to AHCL (n = 8) or continue with MDI + RT-CGM (n = 5) for six months. Prespecified endpoints included the between-group difference in mean change from baseline in HbA1c, CGM-derived measures of glycemic control, and safety. RESULTS: The mean HbA1c level decreased by 1.70 percentage points in the AHCL group versus a 0.60 percentage point decrease in the MDI + RT-CGM group, with a model-based treatment effect of -1.08 percentage points (95% confidence interval [CI] = -2.17 to 0.00 percentage points; P = .0508) in favor of AHCL. The percentage of time spent with sensor glucose levels between 70 and 180 mg/dL in the study phase was 73.6% in the AHCL group and 46.4% in the MDI + RT-CGM group; model-based between-group difference of 28.8 percentage points (95% CI = 12.3 to 45.3 percentage points; P = .0035). No diabetic ketoacidosis or severe hypoglycemia occurred in either group. CONCLUSIONS: In people with T1D with HbA1c ≥8.0%, the use of AHCL resulted in improved glycemic control relative to MDI + RT-CGM. The scale of improvement suggests that AHCL should be considered as an option for people not achieving good glycemic control on MDI + RT-CGM.

Advanced hybrid closed loop therapy versus conventional treatment in adults with type 1 diabetes (ADAPT): a randomised controlled study.

BACKGROUND: Adults with type 1 diabetes who are treated with multiple daily injections of insulin plus intermittently scanned continuous glucose monitoring (isCGM) can have suboptimal glucose control. We aimed to assess the efficacy of an advanced hybrid closed loop (AHCL) system compared with such therapy in this population. METHODS: The Advanced Hybrid Closed Loop Study in Adult Population with Type 1 Diabetes (ADAPT) trial is a prospective, multicentre, open-label, randomised controlled trial that involved 14 centres in three European countries (France, Germany, and the UK). We enrolled patients who were at least 18 years of age, had a type 1 diabetes duration of at least 2 years, HbA1c of at least 8% (64 mmol/mol), and were using multiple daily injections of insulin plus isCGM (cohort A) or real time continuous glucose monitoring (cohort B) for at least 3 months. Here, only results for cohort A are reported. Participants were randomly allocated 1:1 to AHCL therapy or continuation of multiple daily injections of insulin plus continuous glucose monitoring for 6 months with an investigator-blinded block randomisation procedure. Participants and treating clinicians could not be masked to the arm assignment. The primary endpoint was the between-group difference in mean HbA1c change from baseline to 6 months in the intention-to-treat population using AHCL therapy and those using multiple daily injections of insulin plus isCGM. The primary endpoint was analysed using a repeated measures random-effects model with the study arm and period as factors. Safety endpoints included the number of device deficiencies, severe hypoglycaemic events, diabetic ketoacidosis, and serious adverse events. This study is registered with ClinicalTrials.gov, NCT04235504. FINDINGS: Between July 13, 2020, and March 12, 2021, 105 people were screened and 82 randomly assigned to treatment (41 in each arm). At 6 months, mean HbA1c had decreased by 1·54% (SD 0·73), from 9·00% to 7·32% in the AHCL group and 0·20% (0·80) in the multiple daily injections of insulin plus isCGM from 9·07% to 8·91% (model-based difference -1·42%, 95% CI -1·74 to -1·10; p<0·0001). No diabetic ketoacidosis, severe hypoglycaemia, or serious adverse events related to study devices occurred in either group; two severe hypoglycaemic events occurred in the run-in phase. 15 device-related non-serious adverse events occurred in the AHCL group, compared with three in the multiple daily injections of insulin plus isCGM group. Two serious adverse events occurred (one in each group), these were breast cancer (in one patient in the AHCL group) and intravitreous haemorrhage (in one patient in the multiple daily injections of insulin plus isCGM group). INTERPRETATION: In people with type 1 diabetes using multiple daily injections of insulin plus isCGM and with HbA1c of at least 8%, the use of AHCL confers benefits in terms of glycaemic control beyond those that can be achieved with multiple daily injections of insulin plus isCGM. These data support wider access to AHCL in people with type 1 diabetes not at target glucose levels. FUNDING: Medtronic International Trading Sàrl.

Graphene nanoplatelet doping of P3HT:PCBM photoactive layer of bulk heterojunction organic solar cells for enhancing performance.

Hybrid organic photovoltaic (OPV) cells based on conjugated polymer photoactive materials are promising candidates for flexible, high-performance and low-cost energy sources owing to their inexpensive materials, cost-effective processing and ease of fabrication by simple solution processes. However, the modest PV performance obtained to date-in particular the low power conversion efficiency (PCE)-has impeded the large scale deployment of OPV cells. The low PCE in OPV solar cells is mainly attributed to the low carrier mobility, which is closely correlated to the transport diffusion length of the charge carriers within the photoactive layers. The 2D graphene material could be an excellent candidate for assisting charge transport improvement in the active layer of OPV cells, due to its huge carrier mobility, thermal and chemical stability, and its compatibility with the solution process. In this work, we report on the improvement of the optoelectronic properties and photovoltaic performance of graphene nanoplatelet (GNP)-doped P3HT:PCBM photoactive blended layers, integrated into a bulk heterojunction (BHJ) organic-photovoltaic-based device, using PEDOT:PSS on an ITO/glass substrate. First, the light absorption capacity was observed to increase with respect to the GNP content, while the photoluminescence showed clear quenching, indicating electron transfer between the graphene sheets and the polymeric matrix. Then, the incorporation of GNP into the BHJ active layer resulted in enhanced PV performance with respect to the reference cell, and the best PV performance was obtained with 3 wt.% of GNP loading, with an open-circuit voltage of 1.24 V, a short-circuit current density value of 6.18 mA cm-2, a fill factor of 47.12%, and a power conversion efficiency of about 3.61%. We believe that the obtained results contribute to the development of organic photovoltaic devices and to the understanding of the impact of sp2-bonded carbon therein.

Exposure Assessment in a Single-Walled Carbon Nanotube Primary Manufacturer.

Objectives: This study was aimed at documenting and characterizing occupational exposure to single-walled carbon nanotubes (SWCNTs) generated in a primary manufacturing plant. It also compared various strategies of exposure monitoring. Methods: A 6-day measurement protocol was scheduled (D1-D6) including both (i) quasi-personal monitoring with an array of direct reading instruments (DRIs) and (ii) offline electron microscopy analyses of surface and breathing zone filter-based samples. The first step (D1 and D2) consisted of contamination screenings resulting from the various SWCNT production tasks using a multimetric approach. Surface sampling was also carried out to assess workplace cross-contamination. The second step (D3-D6) focused on the exposure monitoring during recovery/cleaning task, by comparing three personal elemental carbon (EC) measurements [respirable EC using a cyclone following the NIOSH 5040 method (REC-CYC), respirable and thoracic EC using parallel particle impactors [REC-PPI and TEC-PPI, respectively)] and gravimetric mass concentration measurements. Results: DustTrak DRX and electrical low-pressure impactor measurements indicated that particles were released during weighing, transferring, and recovery/cleaning tasks of the manufacturing process. Electron microscopy revealed the presence of agglomerated SWCNTs only during the recovery/cleaning task. REC-CYC concentrations remained under the limits of quantification; REC-PPI showed levels up to 58 µg m-3; and TEC-PPI ranged from 40 to 70 µg m-3. Ratios calculated between gravimetric measurements and estimated DustTrak mass concentrations ranged from 2.8 to 4.9. Cross-contamination appeared to be limited since SWCNTs was only found on surface samples collected close to the reactor in the production room. Conclusions: This case study showed that the DustTrak DRX should be the preferred device among DRIs to identify potential exposure to SWCNTs. However, there is a risk of false positive since it is a non-specific instrument; therefore, the actual release of SWCNTs must be confirmed with scanning electron microscopy/transmission electron microscopy analyses. Besides, using EC measurements as a proxy for SWCNT exposure assessments, as suggested by the NIOSH, is still challenging since interferences can occur with other EC sources such as carbon black, which is also present in the workplace.

A hybrid enrichment process combining conjugated polymer extraction and silica gel adsorption for high purity semiconducting single-walled carbon nanotubes (SWCNT).

A novel purification process for the enrichment of sc-SWCNTs that combines selective conjugated polymer extraction (CPE) with selective adsorption using silica gel, termed hybrid-CPE (h-CPE), has been developed, providing a high purity sc-SWCNT material with a significant improvement in process efficiency and yield. Using the h-CPE protocol, a greater than 5 fold improvement in yield can be obtained compared to traditional CPE while obtaining sc-SWCNT with a purity >99.9% as assessed by absorption spectroscopy and Raman mapping. Thin film transistor devices using the h-CPE derived sc-SWCNTs as the semiconductor possess mobility values ranging from 10-30 cm(2) V(-1) s(-1) and current ON/OFF ratio of 10(4)-10(5) for channel lengths between 2.5 and 20 µm.

Transport logistics in pollen tubes.

Cellular organelles move within the cellular volume and the effect of the resulting drag forces on the liquid causes bulk movement in the cytosol. The movement of both organelles and cytosol leads to an overall motion pattern called cytoplasmic streaming or cyclosis. This streaming enables the active and passive transport of molecules and organelles between cellular compartments. Furthermore, the fusion and budding of vesicles with and from the plasma membrane (exo/endocytosis) allow for transport of material between the inside and the outside of the cell. In the pollen tube, cytoplasmic streaming and exo/endocytosis are very active and fulfill several different functions. In this review, we focus on the logistics of intracellular motion and transport processes as well as their biophysical underpinnings. We discuss various modeling attempts that have been performed to understand both long-distance shuttling and short-distance targeting of organelles. We show how the combination of mechanical and mathematical modeling with cell biological approaches has contributed to our understanding of intracellular transport logistics.

The pollen tube paradigm revisited.

The polar growth process characterizing pollen tube elongation has attracted numerous modeling attempts over the past years. While initial models focused on recreating the correct cellular geometry, recent models are increasingly based on experimentally assessed cellular parameters such as the dynamics of signaling processes and the mechanical properties of the cell wall. Recent modeling attempts have therefore substantially gained in biological relevance and predictive power. Different modeling methods are explained and the power and limitations of individual models are compared. Focus is on several recent models that use closed feedback loops in order to generate limit cycles representing the oscillatory behavior observed in growing tubes.

Sub- and suprathreshold adaptation currents have opposite effects on frequency tuning.

Natural stimuli are often characterized by statistics that can vary over orders of magnitude. Experiments have shown that sensory neurons continuously adapt their responses to changes in these statistics, thereby optimizing information transmission. However, such adaptation can also alter the neuronal transfer function by attenuating if not eliminating responses to the low frequency components of time varying stimuli,which can create ambiguity in the neural code. We recorded from electrosensory pyramidal neurons before and after pharmacological inactivation of either calcium-activated (I(AHP)) or KCNQ voltage-gated potassium currents (I(M)). We found that blocking each current decreased adaptation in a similar fashion but led to opposite changes in the neuronal transfer function. Indeed, blocking I(AHP) increased while blocking I(M) instead decreased the response to low temporal frequencies. To understand this surprising result, we built a mathematical model incorporating each channel type. This model predicted that these differential effects could be accounted for by differential activation properties. Our results show that the mechanisms that mediate adaptation can either increase or decrease the response to low frequency stimuli. As such, they suggest that the nervous system resolves ambiguity resulting from adaptation through independent control of adaptation and the neuronal transfer function.

Modeling pollen tube growth: feeling the pressure to deliver testifiable predictions.

The frequency and amplitude of oscillatory pollen tube growth can be altered by changing the osmotic value of the surrounding medium. This has motivated the proposition that the periodic change in growth velocity is caused by changes in turgor pressure. Using mathematical modeling we recently demonstrated that the oscillatory pollen tube growth does not require turgor to change but that this behavior can be explained with a mechanism that relies on changes in the mechanical properties of the cell wall which in turn are caused by temporal variations in the secretion of cell wall precursors. The model also explains why turgor and growth rate are correlated for oscillatory growth with long growth cycles while they seem uncorrelated for oscillatory growth with short growth cycles. The predictions made by the model are testifiable by experimental data and therefore represent an important step towards understanding the dynamics of the growth behavior in walled cells.

Regulator or driving force? The role of turgor pressure in oscillatory plant cell growth.

Turgor generates the stress that leads to the expansion of plant cell walls during cellular growth. This has been formalized by the Lockhart equation, which can be derived from the physical laws of the deformation of viscoelastic materials. However, the experimental evidence for such a direct correlation between growth rate and turgor is inconclusive. This has led to challenges of the Lockhart model. We model the oscillatory growth of pollen tubes to investigate this relationship. We couple the Lockhart equation to the dynamical equations for the change in material properties. We find that the correct implementation of the Lockhart equation within a feedback loop leading to low amplitude oscillatory growth predicts that in this system changes in the global turgor do not influence the average growth rate in a linear manner, consistent with experimental observations. An analytic analysis of our model demonstrates in which regime the average growth rate becomes uncorrelated from the turgor pressure.

Microfilament orientation constrains vesicle flow and spatial distribution in growing pollen tubes.

The dynamics of cellular organelles reveals important information about their functioning. The spatio-temporal movement patterns of vesicles in growing pollen tubes are controlled by the actin cytoskeleton. Vesicle flow is crucial for morphogenesis in these cells as it ensures targeted delivery of cell wall polysaccharides. Remarkably, the target region does not contain much filamentous actin. We model the vesicular trafficking in this area using as boundary conditions the expanding cell wall and the actin array forming the apical actin fringe. The shape of the fringe was obtained by imposing a steady state and constant polymerization rate of the actin filaments. Letting vesicle flux into and out of the apical region be determined by the orientation of the actin microfilaments and by exocytosis was sufficient to generate a flux that corresponds in magnitude and orientation to that observed experimentally. This model explains how the cytoplasmic streaming pattern in the apical region of the pollen tube can be generated without the presence of actin microfilaments.

Polar growth in pollen tubes is associated with spatially confined dynamic changes in cell mechanical properties.

Cellular morphogenesis involves changes to cellular size and shape which in the case of walled cells implies the mechanical deformation of the extracellular matrix. So far, technical challenges have made quantitative mechanical measurements of this process at subcellular scale impossible. We used micro-indentation to investigate the dynamic changes in the cellular mechanical properties during the onset of spatially confined growth activities in plant cells. Pollen tubes are cellular protuberances that have a strictly unidirectional growth pattern. Micro-indentation of these cells revealed that the initial formation of a cylindrical protuberance is preceded by a local reduction in cellular stiffness. Similar cellular softening was observed before the onset of a rapid growth phase in cells with oscillating growth pattern. These findings provide the first quantitative cytomechanical data that confirm the important role of the mechanical properties of the cell wall for local cellular growth processes. They are consistent with a conceptual model that explains pollen tube oscillatory growth based on the relationship between turgor pressure and tensile resistance in the apical cell wall. To further confirm the significance of cell mechanics, we artificially manipulated the mechanical cell wall properties as well as the turgor pressure. We observed that these changes affected the oscillation profile and were able to induce oscillatory behavior in steadily growing tubes.

Curvature-driven pore growth in charged membranes during charge-pulse and voltage-clamp experiments.

We find that curvature-driven growth of pores in electrically charged membranes correctly reproduces charge-pulse experiments. Our model, consisting of a Langevin equation for the time dependence of the pore radius coupled to an ordinary differential equation for the number of pores, captures the statistics of the pore population and its effect on the membrane conductance. The calculated pore radius is a linear, and not an exponential, function of time, as observed experimentally. Two other important features of charge-pulse experiments are recovered: pores reseal for low and high voltages but grow irreversibly for intermediate values of the voltage. Our set of coupled ordinary differential equations is equivalent to the partial differential equation used previously to study pore dynamics, but permits the study of longer timescales necessary for the simulations of voltage-clamp experiments. An effective phase diagram for such experiments is obtained.

Magnitude and direction of vesicle dynamics in growing pollen tubes using spatiotemporal image correlation spectroscopy and fluorescence recovery after photobleaching.

The delivery of cell wall material and membrane to growing plant cell surfaces requires the spatial and temporal coordination of secretory vesicle trafficking. Given the small size of vesicles, their dynamics is difficult to quantify. To quantitatively analyze vesicle dynamics in growing pollen tubes labeled with the styryl dye FM1-43, we applied spatiotemporal correlation spectroscopy on time-lapse series obtained with high-speed confocal laser scanning microscopy recordings. The resulting vector maps revealed that vesicles migrate toward the apex in the cell cortex and that they accumulate in an annulus-shaped region adjacent to the extreme tip and then turn back to flow rearward in the center of the tube. Fluorescence recovery after photobleaching confirmed vesicle accumulation in the shoulder of the apex, and it revealed that the extreme apex never recovers full fluorescence intensity. This is consistent with endocytotic activity occurring in this region. Fluorescence recovery after photobleaching analysis also allowed us to measure the turnover rate of the apical vesicle population, which was significantly more rapid than the theoretical rate computed based on requirements for new cell wall material. This may indicate that a significant portion of the vesicles delivered to the apex does not succeed in contacting the plasma membrane for delivery of their contents. Therefore, we propose that more than one passage into the apex may be needed for many vesicles before they fuse to the plasma membrane and deliver their contents.

Model for calcium dependent oscillatory growth in pollen tubes.

Experiments have shown that pollen tubes grow in an oscillatory mode, the mechanism of which is poorly understood. We propose a theoretical growth model of pollen tubes exhibiting such oscillatory behaviour. The pollen tube and the surrounding medium are represented by two immiscible fluids separated by an interface. The physical variables are pressure, surface tension, density and viscosity, which depend on relevant biological quantities, namely calcium concentration and thickness of the cell wall. The essential features generally believed to control oscillating growth are included in the model, namely a turgor pressure, a viscous cell wall which yields under pressure, stretch-activated calcium channels which transport calcium ions into the cytoplasm and an exocytosis rate dependent on the cytosolic calcium concentration in the apex of the cell. We find that a calcium dependent vesicle recycling mechanism is necessary to obtain an oscillating growth rate in our model. We study the variation in the frequency of the growth rate by changing the extracellular calcium concentration and the density of ion channels in the membrane. We compare the predictions of our model with experimental data on the frequency of oscillation versus growth speed, calcium concentration and density of calcium channels.