Computing thermomechanical properties of dry homopolymers used as raw materials for formulation of biomedical hydrogels

Different static properties have been calculated with COMPASS force field for polyacrylamide, poly(2-hydroxyethylacrylate) (HEA), poly(2-hydroxyethylmethacrylate) (HEMA), poly(glycidylmethacrylate) (GMA), polyethylene glycol (PEG), and poly(2,2,2-trifluoroethylmethacrylate) (TFEM). For each polymers, the calculated values were averaged on five equilibrated configurations of amorphous cell composed of one atactic chain containing 100 repeat units. The ranking obtained from the densities calculated at 300 K is TFEM?>?HEA?≈?xpolycrylamide?>?HEMA?≈?GMA?>?PEG. Concerning the glass transition temperature we have obtained polyacrylamide?>?HEMA?≈?GMA?≈?HEA?>?PEG, and polyacrylamide?>?HEMA?≈?HEA?>?GMA?≈?PEG?>?TFEM for the bulk modulus. The calculated results, when available, have been compared with experimental data coming from literature.     

Vampire blood: respiratory physiology of the vampire squid (Cephalopoda: Vampyromorpha) in relation to the oxygen minimum layer

The functional properties of the haemocyanin ofVampyroteuthis infernalis (Cephalopoda: Vampyromorpha), measured at 5 °C, are reported and discussed in relation to hypoxia. The oxygen affinity of this haemocyanin (P₅₀=0.47−0.55 kPa) is higher than any previously measured for a cephalopod. The high cooperativity (n₅₀=2.20−2.23) and Bohr coefficient (−0.22) suggest a true transport function for this haemocyanin. This high-affinity haemocyanin, in conjunction with moderate gill diffusion capacity, provides a sufficient oxygen gradient from the environment to the blood to support the low routine oxygen consumption rate of V. infernalis     

Rapid Diagnosis of Lung Tumors,a Feasability Study Using Maldi-Tof Mass Spectrometry

ObjectiveDespite recent advances in imaging and core or endoscopic biopsies, a percentage of patients have a major lung resection without diagnosis. We aimed to assess the feasibility of a rapid tissue preparation/analysis to discriminate cancerous from non-cancerous lung tissue.MethodsFresh sample preparations were analyzed with the Microflex LT^TM MALDI-TOF analyzer. Each main reference spectra (MSP) was consecutively included in a database. After definitive pathological diagnosis, each MSP was labeled as either cancerous or non-cancerous (normal, inflammatory, infectious nodules). A strategy was constructed based on the number of concordant responses of a mass spectrometry scoring algorithm. A 3-step evaluation included an internal and blind validation of a preliminary database (n = 182 reference spectra from the 100 first patients), followed by validation on a whole cohort database (n = 300 reference spectra from 159 patients). Diagnostic performance indicators were calculated.Results127 cancerous and 173 non-cancerous samples (144 peripheral biopsies and 29 inflammatory or infectious lesions) were processed within 30 minutes after biopsy sampling. At the most discriminatory level, the samples were correctly classified with a sensitivity, specificity and global accuracy of 92.1%, 97.1% and 95%, respectively.ConclusionsThe feasibility of rapid MALDI-TOF analysis, coupled with a very simple lung preparation procedure, appears promising and should be tested in several surgical settings where rapid on-site evaluation of abnormal tissue is required. In the operating room, it appears promising in case of tumors with an uncertain preoperative diagnosis and should be tested as a complementary approach to frozen-biopsy analysis.     

Aspiration of THP1 into a micropipette. Mechanical deformation of monocytic THP-1 cells: occurrence of two sequential phases with differential sensitivity to metabolic inhibitors

Blood leukocytes can exhibit extensive morphological changes during their passage through small capillary vessels. The human monocytic THP-1 cell line was used to explore the metabolic dependence of these changes in shape. Cells were aspirated into micropipettes for determination of the rate of protrusion formation. They were then released and the kinetics of morphological recovery was studied. Results were consistent with Evans’ model (Blood 64:1028, 1984) of a viscous liquid droplet surrounded by a tensile membrane. The estimated values of cytoplasmic viscosity and membrane tension were 162 Pa.s and 0.0142 mN/m respectively. The influence of metabolic inhibitors on cell mechanical behavior was then studied: results strongly suggested that deformation involved two sequential phases. The cell elongation rate measured during the first 30 s following the onset of aspiration was unaffected by azide, an inhibitor of energy production, and it was about doubled by cytochalasin D, a microfilament inhibitor, and colchicine, a microtubule inhibitor. However, during the following 2 min, deformation was almost abolished in cells treated with azide and cytochalasin D, whereas the protrusion of control cells exhibited an approximately threefold increase in length. It is concluded that, although cells seemed to deform as passive objects, active metabolic processes were required to allow extensive morphological changes triggered by external forces.     

Cross‐genus adoptions in delphinids: One example with taxonomic discussion

Although relatively rare, adoptions have been reported in a number of mammals, involving almost exclusively individuals of the same species, and hardly ever between species or across genera. Adoption remains poorly documented and its proximate causes are controversial. Here, we describe a unique case of a cross‐genus adoption within a small community of common bottlenose dolphins (Tursiops truncatus) at Rangiroa Atoll in French Polynesia. It involves a foster female adopting a presumed melon‐headed whale (Peponocephala electra) calf while already mothering its presumed biological offspring. While the inclusive fitness hypothesis can be rejected for this adult female mother, acquisition of parental skills is also unlikely to have driven adoption in parallel to natural motherhood. We argue that the primiparous foster mother’s inexperience and personality may have contributed to factors driving such non‐adaptive behavior. We also propose that the adoptee’s persistence in initiating and maintaining an association with the adult female bottlenose dolphin could have played a major role in the adoption’s ultimate success, as well as the persistence of this cross‐genus adoption after the disappearance of the biological offspring. A brief discussion of adoption and hybridization within the Delphinidae taxon is included to identify how this cross‐genus adoption fits into context of marine mammal parental care.