Physical modelling of amorphous thermoplastic polymer and numerical simulation of micro hot embossing process

Micro hot embossing process is considered as one of the most promising micro replication processes for manufacturing of polymeric components, especially for the high aspect ratio components and large surface structural components. A large number of hot embossing experimental results have been published, the material modelling and processes simulation to improve the quality of micro replication by hot embossing process are still lacking. This paper consists to 3D modelling of micro hot embossing process with amorphous thermoplastic polymers, including the mechanical characterisation of polymers properties, identification of the viscoelastic behaviour law of the polymers, numerical simulation and experimental investigation of micro hot embossing process. Static compression creep tests have been carried out to investigate the selected polymers’ viscoelastic properties. The Generalized Maxwell model has been proposed to describe the relaxation modulus of the polymers and good agreement has been observed. The numerical simulation of the hot embossing process in 3D has been achieved by taking into account the viscoelastic behaviour of the polymers. The microfluidic devices with the thickness of 2 mm have been elaborated by hot embossing process. The hot embossing process has been carried out using horizontal injection/compression moulding equipment, especially developed for this study. A complete compression mould tool, equipped with the heating system, the cooling system, the ejection system and the vacuum system, has been designed and elaborated in our research. Polymer-based microfluidic devices have been successfully replicated by the hot embossing process using the compression system developed. Proper agreement between the numerical simulation and the experimental elaboration has been observed. It shows strong possibility for the development of the 3D numerical model to optimize the micro hot embossing process in the future

The onset and mastery of spatial language in children acquiring British Sign Language

In the course of language development children must solve arbitrary form-to-meaning mappings, in which semantic components are encoded onto linguistic labels. Because sign languages describe motion and location of entities through iconic movements and placement of the hands in space, child signers may find spatial semantics-to-language mapping easier to learn than child speakers. This hypothesis was tested in two studies: a longitudinal analysis of a native signing child's use of British Sign Language to describe motion and location events between the ages 1–10 and 3–0, and performance of 18 native signing children between the ages of 3–0 and 4–11 on a motion and location sentence comprehension task. The results from both studies argue against a developmental advantage for sign language learners for the acquisition of motion and location forms. Early forms point towards gesture and embodied actions followed by protracted mastery of the use of signs in representational space. The understanding of relative spatial relations continues to be difficult, despite the iconicity of these forms in the language, beyond 5 years of age

Telavancin for hospital-acquired pneumonia: Clinical response and 28-day survival

U.S. Food and Drug Administration draft guidance for future antibiotic clinical trials of bacterial nosocomial pneumonia recommends the use of diagnostic criteria according to American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines and the use of a primary endpoint of 28-day all-cause mortality. The effect of applying these guidelines on outcomes of phase III nosocomial pneumonia studies of telavancin was evaluated in a post hoc analysis. ATS/IDSA criteria were applied in a blind fashion to the original all-treated (AT) group. Clinical cure rates at final follow-up were determined in the refined AT and clinically evaluable (CE) groups (ATS/IDSA-AT and ATS/IDSA-CE, respectively). The exploratory endpoint of 28-day survival was evaluated for the ATS/IDSA-AT group. Noninferiority of telavancin versus vancomycin was demonstrated, with similar cure rates in the ATS/IDSA-AT (59% versus 59%) and ATS/IDSA-CE (83% versus 80%) groups. Cure rates favored telavancin in ATS/IDSA-CE patients where Staphylococcus aureus was the sole pathogen (86% versus 75%). Overall, 28-day survival rates were similar in the telavancin (76%) and vancomycin (77%) groups but lower in telavancin-treated patients with preexisting moderate-to-severe renal impairment (creatinine clearance [CL(CR)] of <50 ml/min). Telavancin should be administered to patients with moderate-to-severe renal impairment only if treatment benefit outweighs the risk or if no suitable alternatives are available

MAX: Development of a Laue diffraction lens for nuclear astrophysics

The next generation of instrumentation for nuclear astrophysics will have to achieve an improvement in sensitivity by a factor of 10-100 over present technologies. With the focusing gamma-ray telescope MAX we take up this challenge and propose to combine the required sensitivity with high spectral and angular resolution, and the capability to measure the polarization of the photons. MAX is a space-borne crystal diffraction telescope, featuring a broad-band Laue lens optimized for the observation of compact sources in two wide energy bands of high astrophysical relevance. Gamma rays will be focused from the large collecting area of a crystal diffraction lens onto a very small detector volume. As a consequence, the signal to background ratio is greatly enhanced, leading to unprecedented sensitivities

Antibody responses to the full-length VAR2CSA and its DBL domains in Cameroonian children and teenagers

Additional file 2. IgG levels to VAR2CSA domains in 10–15 year old Cameroonian girls living in Ngali II and Ntouessong villages. IgG levels to VAR2CSA DBL domains and full-length protein (FV2) were measured in 11–15 year old girls residing in Ngali II and Ntouessong villages. DBL1 domain was from 3D7 strain and all the other proteins from FCR3 parasite strain. Median MFI and Inter-Quartile Range (IQR) are plotted

Mycobacterium tuberculosis Responds to Chloride and pH as Synergistic Cues to the Immune Status of its Host Cell

PubMed ID: 23592993This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited