Optimization of the processing of bio based polymer sustainable products

Polylactic Acid (PLA) is processed by injection moulding technology. The main aim of this study is to provide guidelines for mould and part design, namely to cope with the shrinkage effect and the ejection forces related to the use of bio based polymers. Furthermore optimization of the overall process will be investigated as well as the influence of different parameters to the process and product properties. Draft angle, mould temperature and holding pressure will be related to the ejection forces and the level of shrinkage that occurs

An accurate description of quantum size effects in InP nanocrystallites over a wide range of sizes

We obtain an effective parametrization of the bulk electronic structure of InP within the Tight Binding scheme. Using these parameters, we calculate the electronic structure of InP clusters with the size ranging upto 7.5 nm. The calculated variations in the electronic structure as a function of the cluster size is found to be in excellent agreement with experimental results over the entire range of sizes, establishing the effectiveness and transferability of the obtained parameter strengths.Comment: 9 pages, 3 figures, pdf file available at http://sscu.iisc.ernet.in/~sampan/publications.htm

Photonic crystal carpet: Manipulating wave fronts in the near field at 1550 nm

Ground-plane cloaks, which transform a curved mirror into a flat one, and recently reported at wavelengths ranging from the optical to the visible spectrum, bring the realm of optical illusion a step closer to reality. However, all carpet-cloaking experiments have thus far been carried out in the far-field. Here, we demonstrate numerically and experimentally that a dielectric photonic crystal (PC) of a complex shape made of a honeycomb array of air holes can scatter waves in the near field like a PC with a at boundary at stop band frequencies. This mirage effect relies upon a specific arrangement of dielectric pillars placed at the nodes of a quasi-conformal grid dressing the PC. Our carpet is shown to work throughout the range of wavelengths 1500nm to 1650nm within the stop band extending from 1280 to 1940 nm. The device has been fabricated using a single- mask advanced nanoelectronics technique on III-V semiconductors and the near field measurements have been carried out in order to image the wave fronts's curvatures around the telecommunication wavelength 1550 nm.Comment: 6 page

Tight-binding g-Factor Calculations of CdSe Nanostructures

The Lande g-factors for CdSe quantum dots and rods are investigated within the framework of the semiempirical tight-binding method. We describe methods for treating both the n-doped and neutral nanostructures, and then apply these to a selection of nanocrystals of variable size and shape, focusing on approximately spherical dots and rods of differing aspect ratio. For the negatively charged n-doped systems, we observe that the g-factors for near-spherical CdSe dots are approximately independent of size, but show strong shape dependence as one axis of the quantum dot is extended to form rod-like structures. In particular, there is a discontinuity in the magnitude of g-factor and a transition from anisotropic to isotropic g-factor tensor at aspect ratio ~1.3. For the neutral systems, we analyze the electron g-factor of both the conduction and valence band electrons. We find that the behavior of the electron g-factor in the neutral nanocrystals is generally similar to that in the n-doped case, showing the same strong shape dependence and discontinuity in magnitude and anisotropy. In smaller systems the g-factor value is dependent on the details of the surface model. Comparison with recent measurements of g-factors for CdSe nanocrystals suggests that the shape dependent transition may be responsible for the observations of anomalous numbers of g-factors at certain nanocrystal sizes.Comment: 15 pages, 6 figures. Fixed typos to match published versio

Does Pelletizing Catalysts Influence the Efficiency Number of Activity Measurements? Spectrochemical Engineering Considerations for an Accurate Operando Study

International audienc

Native-MS analysis of monoclonal antibody conjugates by Fourier transform ion cyclotron resonance mass spectrometry

Antibody drug conjugates (ADCs) are an important class of therapeutic molecule currently being used to treat HER2-positive metastatic breast cancer, relapsed or refractory Hodgkin lymphoma, systemic anaplastic large cell lymphoma, relapsed or refractory B-cell precursor acute lymphoblastic leukemia and acute myeloid leukemia. An ADC typically consists of a small molecule or peptide-based cytotoxic moiety covalently linked, via lysine or cysteine residues, to amonoclonal antibody (mAb) scaffold. Mass spectrometric (MS) characterization of these molecules afford highly accurate molecular weight (MW) and drug-to-antibody ratio (DAR) determination, and is typically performed using orthogonal acceleration time-of-flight (oa-ToF) analysers and more recently Orbitrap instruments. Herein we describe for the first time the use of a 15 Tesla solariX Fourier transform ion cyclotron mass spectrometer to characterize an IgG1 mAb molecule conjugated with biotin via native lysine and cysteine residues, under native-MS and solution conditions. The cysteine biotin conjugates remained fully intact, demonstrating the ability of the FT-ICR to maintain the noncovalent interactions and efficiently transmit labile protein complexes. Native-MS was acquired and is displayed in magnitude mode using a symmetric Hann apodisation function. Baseline separation is achieved on all covalent biotin additions, for each charge state, for both the lysine and cysteine biotin-conjugates. Average DAR values obtained by native-MS for the lysine conjugate are compared to those derived by denaturing reversed phase liquid chromatography using an oa-ToF MS system (1.56 ±0.02 versus 2.24 ±0.02 for a 5-molar equivalent and 3.99 ±0.09 versus 4.43 ±0.01 for a 10-molar equivalent, respectively). Increased DAR value accuracy can be obtained for the higher biotin load, when using standard ESI conditions as opposed to nanoESI native-MS conditions. Both denatured LC-MS and native-MS spectral data were deconvoluted using a parsimonious based algorithm, without the need for parameter adjustment

Matrix elasticity of void-forming hydrogels controls transplanted-stem-cell-mediated bone formation

The effectiveness of stem cell therapies has been hampered by cell death and limited control over fate. These problems can be partially circumvented by using macroporous biomaterials that improve the survival of transplanted stem cells and provide molecular cues to direct cell phenotype. Stem cell behaviour can also be controlled in vitro by manipulating the elasticity of both porous and non-porous materials, yet translation to therapeutic processes in vivo remains elusive. Here, by developing injectable, void-forming hydrogels that decouple pore formation from elasticity, we show that mesenchymal stem cell (MSC) osteogenesis in vitro, and cell deployment in vitro and in vivo, can be controlled by modifying, respectively, the hydrogel’s elastic modulus or its chemistry. When the hydrogels were used to transplant MSCs, the hydrogel’s elasticity regulated bone regeneration, with optimal bone formation at 60 kPa. Our findings show that biophysical cues can be harnessed to direct therapeutic stem cell behaviours in situ

First-in-human real-time AI-assisted instrument deocclusion during augmented reality robotic surgery

The integration of Augmented Reality (AR) into daily surgical practice is withheld by the correct registration of pre-operative data. This includes intelligent 3D model superposition whilst simultaneously handling real and virtual occlusions caused by the AR overlay. Occlusions can negatively impact surgical safety and as such deteriorate rather than improve surgical care. Robotic surgery is particularly suited to tackle these integration challenges in a stepwise approach as the robotic console allows for different inputs to be displayed in parallel to the surgeon. Nevertheless, real-time de-occlusion requires extensive computational resources which further complicates clinical integration. This work tackles the problem of instrument occlusion and presents, to the authors' best knowledge, the first-in-human on edge deployment of a real-time binary segmentation pipeline during three robot-assisted surgeries: partial nephrectomy, migrated endovascular stent removal, and liver metastasectomy. To this end, a state-of-the-art real-time segmentation and 3D model pipeline was implemented and presented to the surgeon during live surgery. The pipeline allows real-time binary segmentation of 37 non-organic surgical items, which are never occluded during AR. The application features real-time manual 3D model manipulation for correct soft tissue alignment. The proposed pipeline can contribute towards surgical safety, ergonomics, and acceptance of AR in minimally invasive surgery.This works presents the first-in-human edge deployment of a real-time AI-enabled augmented reality (AR) pipeline in robotic surgery. The application uses a binary segmentation model to effectively identify over 37 classes of non-organic items in the surgical scene, and uses this information to create an overlay visualization, solving the instrument occlusion problem, and preventing the possibly hazardous situation this implies, as well as adding a sense of depth to the AR. The solution is used during three real surgeries and segmentation results, application performance as well as qualitative surgical feedback are discussed.###imag

Matrix elasticity of void-forming hydrogels controls transplanted-stem-cell-mediated bone formation

The effectiveness of stem cell therapies has been hampered by cell death and limited control over fate. These problems can be partially circumvented by using macroporous biomaterials that improve the survival of transplanted stem cells and provide molecular cues to direct cell phenotype. Stem cell behaviour can also be controlled in vitro by manipulating the elasticity of both porous and non-porous materials, yet translation to therapeutic processes in vivo remains elusive. Here, by developing injectable, void-forming hydrogels that decouple pore formation from elasticity, we show that mesenchymal stem cell (MSC) osteogenesis in vitro, and cell deployment in vitro and in vivo, can be controlled by modifying, respectively, the hydrogel's elastic modulus or its chemistry. When the hydrogels were used to transplant MSCs, the hydrogel's elasticity regulated bone regeneration, with optimal bone formation at 60 kPa. Our findings show that biophysical cues can be harnessed to direct therapeutic stem cell behaviours in situ