Some general features of limited coalescence in solid-stabilized emulsions

We produce direct and inverse emulsions stabilized by solid mineral particles. If the total amount of particles is initially insufficient to fully cover the oil-water interfaces, the emulsion droplets coalesce such that the total interfacial area between oil and water is progressively reduced. Since it is likely that the particles are irreversibly adsorbed, the degree of surface coverage by them increases until coalescence is halted. We follow the rate of droplet coalescence from the initial fragmented state to the saturated situation. Unlike surfactant-stabilized emulsions, the coalescence frequency depends on time and particle concentration. Both the transient and final droplet size distributions are relatively narrow and we obtain a linear relation between the inverse average droplet diameter and the total amount of solid particles, with a slope that depends on the mixing intensity. The phenomenology is independent of the mixing type and of the droplet volume fraction allowing the fabrication of both direct and inverse emulsion with average droplet sizes ranging from micron to millimetre.

Epidemiology of severe brain injuries: a prospective population-based study

BACKGROUND

The aim of this prospective study was to estimate annual incidences of hospitalization for severe traumatic brain injury (TBI) (maximum Abbreviated Injury Score in the head region [HAIS] 4 or 5) in a defined population of 2.8 million.

METHODS

Severe TBI patients were included in the emergency departments in the 19 hospitals of the region. A prospective data form was completed with initial neurologic state, computed tomographic scan lesions, associated injuries, length of unconsciousness, and length of stay in acute care centers. Outcome at the time the patient left acute hospitalization was retrospectively assessed from medical notes.

RESULTS

During the 1-year period (1996), 497 residents fulfilled the inclusion criteria, leading to an annual incidence rate of 17.3 per 100,000 population; 58.1% were HAIS5. Mortality rate was 5.2 per 100,000. Men accounted for 71.4% of cases. Median age was 44 years, with a quarter of patients more than 70 years old. Traffic accidents were the most frequent causes (48.3%), but falls accounted for 41.8% of all patients. Age and severity were different according to the major categories of external causes. In HAIS5 patients, 86.5% were considered as comatose (coma lasting more than 24 hours or leading to immediate death) but only 60.9% had an initial Glasgow Coma Scale score < 9. In the HAIS4 group, 7.2% had an initial Glasgow Coma Scale score < 9. Fatality rates were 30.0% in the whole study group, 7.7% in HAIS4, 12.8% in HAIS5 without coma, and 51.2% in HAIS5 with coma.

CONCLUSION

This study shows a decrease in severe TBI incidence when results are compared with another study conducted 10 years earlier in the same region. This is because of a decrease in traffic accidents. However, this results in an increase in the proportion of falls in elderly patients and an increase in the median age in our patients. This increased age influences the mortality rate.

Fluid phase generation of terminal complement complex as a novel index of bioincompatibility

Blood membrane interactions in hemodialysis have been shown to trigger complement (C) activation. As indicators of C-activation the anaphylatoxins (C3a and C5a) are problematical because of methodological difficulties and their kinetic properties. We developed a sensitive and specific micro-ELISA using a monoclonal antibody against neoantigens on the terminal complement complex (TCC); highly purified human TCC served as standard. Concentrations of TCC were measured in single-path perfusion systems (in vitro) and in the blood lines (arterial inlet; venous outlet) of patients on hemodialysis using steam-sterilized or ETO-sterilized dialyzers with the following membranes: cuprophan (CU), hemophan (HE) and polysulfone F6 (PS), respectively. All dialyzers with identical geometry were run under identical conditions. All membranes tested caused continuously ongoing net generation of TCC. In vitro, contact of serum with CU minidialyzers resulted in fivefold higher net release of TCC compared with HE and PS. In vivo TCC concentration-time profiles differed significantly between membranes in the rank order CU much much greater than HE greater than PS (mean basal concentration 58 x 10(-11) M; peak increase over baseline with CU 40-fold, HE fourfold, PS threefold). In addition, more TCC was generated from the same dialyzers with ETO than steam sterilization. TCC differed from C3a and C5a in the following respects: (i) lower detection limit (4 x 10(-11) vs. less than 5 x 10(-9) M for both C-anaphylatoxins); (ii) higher relative increment (inlet) during CU dialysis (25-fold vs. eightfold and twofold, respectively); (iii) C-anaphylatoxins yielded the same ranking (CU much greater than HE greater than PS), but TCC concentrations were not a linear function of C3a or C5a concentrations, respectively. Kinetic analysis (Bateman function) showed significant differences of invasion constants between membranes, that is, CU 0.088 min-1, HE 0.09, PS 0.168. The net amount of TCC released from the dialyzer was calculated under certain assumptions. It was 75.5 mg/4 hr for CU, 7.3 for HE and 5.0 for PS. The elimination constant was also dependent on the type of membrane. Using flow cytofluorometry and immunohistochemical methods (APAAP), TCC was demonstrated on membranes of granulocytes obtained during dialysis; this is compatible with potential in vivo cell activation. Generation of PGE2 and TNF alpha by adherent monocytes induced by cuprophan was C8 dependent: levels were significantly increased by addition of C8 to C8 deficient human serum concomitantly with generation of TCC.(ABSTRACT TRUNCATED AT 250 WORDS)

RAB3GAP1 and RAB3GAP2 modulate basal and rapamycin-induced autophagy

Macroautophagy is a degradative pathway that sequesters and transports cytosolic cargo in autophagosomes to lysosomes, and its deterioration affects intracellular proteostasis. Membrane dynamics accompanying autophagy are mostly elusive and depend on trafficking processes. RAB GTPase activating proteins (RABGAPs) are important factors for the coordination of cellular vesicle transport systems, and several TBC (TRE2-BUB2-CDC16) domain-containing RABGAPs are associated with autophagy. Employing C. elegans and human primary fibroblasts, we show that RAB3GAP1 and RAB3GAP2, which are components of the TBC domain-free RAB3GAP complex, influence protein aggregation and affect autophagy at basal and rapamycin-induced conditions. Correlating the activity of RAB3GAP1/2 with ATG3 and ATG16L1 and analyzing ATG5 punctate structures, we illustrate that the RAB3GAPs modulate autophagosomal biogenesis. Significant levels of RAB3GAP1/2 colocalize with members of the Atg8 family at lipid droplets, and their autophagy modulatory activity depends on the GTPase-activating activity of RAB3GAP1 but is independent of the RAB GTPase RAB3. Moreover, we analyzed RAB3GAP1/2 in relation to the previously reported suppressive autophagy modulators FEZ1 and FEZ2 and demonstrate that both reciprocally regulate autophagy. In conclusion, we identify RAB3GAP1/2 as novel conserved factors of the autophagy and proteostasis network.

Characterization of echoviruses that bind decay accelerating factor (CD55): evidence that some haemagglutinating strains use more than one cellular receptor

Several echoviruses (EVs) have previously been shown to use decay accelerating factor (DAF) as a cellular receptor. Since DAF is expressed on erythrocytes, EVs that use this receptor cause haemagglutination. Here we show that all EVs that haemagglutinate do so via attachment to DAF and that this interaction can be inhibited by a monoclonal antibody (MAb) specific for DAF domain SCR3. Although the viruses haemagglutinate via DAF some can bind to rhabdomyosarcoma cells from which DAF has been removed and infect in the presence of a MAb against DAF. This suggests that some EVs have the capacity to interact with more than one cellular receptor.

Synthesis of surfactant-free micro- and nanolatexes from Pickering emulsions stabilized by acetylated cellulose nanocrystals

Surfactant-free micro- and nanolatexes from Pickering emulsions stabilized by acetylated cellulose nanocrystals (CNCs).

Coarsening of alkane-in-water emulsions stabilized by nonionic poly(oxyethylene) surfactants: the role of molecular permeation and coalescence

We produce different alkane-in-water concentrated emulsions stabilized by the same nonionic surfactant, and we follow their kinetic evolution by granulometry. The size distribution becomes remarkably narrow during the first stages of coarsening and progressively turns to a wide function as time passes. We get evidence that the size evolution occurs under the effect of molecular permeation and coalescence. A second hydrophobic species of large molecular size is dissolved in the dispersed phase. This latter is expected to inhibit the permeation mechanism, and coalescence should act alone. Surprisingly, coalescence is also suppressed, even at a very low concentration of the second component (approximately 1% w/w). We vary the chemical nature and concentration of the second species, and we propose a simple mechanism to explain the stabilizing effect with respect to coalescence.

κB-Ras proteins regulate both NF-κB-dependent inflammation and Ral-dependent proliferation

The transformation of cells generally involves multiple genetic lesions that undermine control of both cell death and proliferation. We now report that κB-Ras proteins act as regulators of NF-κB and Ral pathways, which control inflammation/cell death and proliferation, respectively. Cells lacking κB-Ras therefore not only show increased NF-κB activity, which results in increased expression of inflammatory mediators, but also exhibit elevated Ral activity, which leads to enhanced anchorage-independent proliferation (AIP). κB-Ras deficiency consequently leads to significantly increased tumor growth that can be dampened by inhibiting either Ral or NF-κB pathways, revealing the unique tumor-suppressive potential of κB-Ras proteins. Remarkably, numerous human tumors show reduced levels of κB-Ras, and increasing the level of κB-Ras in these tumor cells impairs their ability to undergo AIP, thereby implicating κB-Ras proteins in human disease.

Rheological Behavior of Fluorinated Highly Concentrated Reverse Emulsions with Temperature

Reverse highly concentrated fluorinated emulsions exist in a large temperature domain (between 10 and 50 degrees C). The study of the phase behavior reveals that the continuous medium composition varied with the temperature. Highly concentrated emulsions behave as elastic solids. Monitoring the evolution of their elasticity with time as a function of temperature by rheology is an original way to characterize their aging. This method was used to get more insight into the modification of the behavior of polydisperse emulsions with temperature and time. The elastic modulus decreased exponentially with time in the range of temperatures studied. This was interpreted as a result of coalescence due to a single film rupture frequency which was independent of its thickness. This coalescence mechanism is thermally activated with an activation energy of 50 k(B)T. Copyright 1999 Academic Press.

Peripheral neuropathy as initial manifestation of primary systemic vasculitides

Peripheral neuropathies are well-known complications of primary systemic vasculitides. In rare cases, peripheral neuropathies are among the first symptoms of these diseases. In this prospective study, 89 consecutive adult patients with newly diagnosed primary systemic vasculitis were screened, of whom 22 patients (25 %, 12 men, ten women, mean age, 59 years, range, 26-82 years) suffered from peripheral neuropathy due to systemic vasculitis at initial presentation. Peripheral neuropathy was most frequent in newly diagnosed patients with eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome, 12 out of 20 patients, 60 %) and polyarteritis nodosa (three out of six patients, 50 %), and less common in patients with granulomatosis with polyangiitis (six out of 47 patients, 13 %) and microscopic polyangiitis (one out of 16 patients, 6 %). Multiplex mononeuropathy was more frequent (n = 13, 59 %) than symmetric polyneuropathy (n = 9, 41 %). The nerves commonly affected were the peroneal nerve, followed by the sural, posterior tibial, and median nerves. Treatment options were chosen according to current guidelines of the national neurological and rheumatologic societies, with initial corticosteroid monotherapy for patients with a mild disease form and a combination of corticosteroids and intravenously pulsed cyclophosphamide for patients with a more extended organ involvement. During follow-up (mean, 34 months, range, 12-112 months), new neurological complications were rare (9 %): One patient suffered from a cerebral infarct while another patient sustained epileptic seizures. Two patients (9 %) died from sepsis (after 60 months) or severe gastrointestinal bleeding (after 13 months). The degree of neurological disability measured by the functional disability score (described by Prineas) improved in 20 of 22 patients after 12 months of therapy.

Coupling a quantum dot, fermionic leads, and a microwave cavity on a chip

We demonstrate a hybrid architecture consisting of a quantum dot circuit coupled to a single mode of the electromagnetic field. We use single wall carbon nanotube based circuits inserted in superconducting microwave cavities. By probing the nanotube dot using a dispersive readout in the Coulomb blockade and the Kondo regime, we determine an electron-photon coupling strength which should enable circuit QED experiments with more complex quantum dot circuits.

Interleukin-36 receptor mediates the crosstalk between plasma cells and synovial fibroblasts

The IL-1 family member IL-36α has proinflammatory and pathogenic properties in psoriasis. IL-36α binds to the IL-36 receptor leading to nuclear factor kappa B/mitogen activated protein kinase mediated cytokine release. The IL-36R antagonist prevents recruitment of IL-1 receptor accessory protein and therefore IL-36-dependent cell activation. In inflamed human tissue, we previously could show that resident B cells and plasma cells (PC) express IL-36α. Further, fibroblast-like synoviocytes (FLS) produced proinflammatory cytokines upon IL-36α-stimulation. We hypothesize an IL-36-specific crosstalk between B cells/PCs and FLS permitting a proinflammatory B cell niche. Here, we firstly demonstrated that B cell lines and B cells from healthy donors express IL-36α and stimulation increased IL-36α in B cells and primary plasmablasts/PCs. Moreover, FLS respond specifically to IL-36α by proliferation and production of matrix metalloproteinases via p38/HSP27 signaling. Importantly, IL-36R-deficiency abrogated IL-36α-induced production of inflammatory mediators in FLS and changed the intrinsic FLS-phenotype. Using an in vitro co-culture system, we could show that IL-36R-deficient FLS had a limited capacity to support PC survival compared to wild-type FLS. Hence, we demonstrated an IL-36R-dependent crosstalk between B cells/PCs and FLS. Our data support the concept of initiation and maintenance of a proinflammatory niche by B cells in the joints.

Bacterial protein domains with a novel Ig-like fold target human CEACAM receptors

Streptococcus agalactiae, also known as group B Streptococcus (GBS), is the major cause of neonatal sepsis in humans. A critical step to infection is adhesion of bacteria to epithelial surfaces. GBS adhesins have been identified to bind extracellular matrix components and cellular receptors. However, several putative adhesins have no host binding partner characterised. We report here that surface-expressed β protein of GBS binds to human CEACAM1 and CEACAM5 receptors. A crystal structure of the complex showed that an IgSF domain in β represents a novel Ig-fold subtype called IgI3, in which unique features allow binding to CEACAM1. Bioinformatic assessment revealed that this newly identified IgI3 fold is not exclusively present in GBS but is predicted to be present in adhesins from other clinically important human pathogens. In agreement with this prediction, we found that CEACAM1 binds to an IgI3 domain found in an adhesin from a different streptococcal species. Overall, our results indicate that the IgI3 fold could provide a broadly applied mechanism for bacteria to target CEACAMs.

Formulation and mechanical properties of emulsion-based model polymer foams

We produce cellular material based on the formulation of model emulsions whose drop size and composition may be continuously tuned. The obtained solid foams are characterized by narrow cell and pore size distributions in direct relation with the emulsion structure. The mechanical properties are examined, by varying independently the cell size and the foam density, and compared to theoretical predictions. Surprisingly, at constant density, Young's modulus depends on the cell size. We believe that this observation results from the heterogeneous nature of the solid material constituting the cell walls and propose a mean-field approach that allows describing the experimental data. We discuss the possible origin of the heterogeneity and suggest that the presence of an excess of surfactant close to the interface results in a softer polymer layer near the surface and a harder layer in the bulk.

Characterization of a two-transmon processor with individual single-shot qubit readout

We report the characterization of a two-qubit processor implemented with two capacitively coupled tunable superconducting qubits of the transmon type, each qubit having its own nondestructive single-shot readout. The fixed capacitive coupling yields the sqrt[iSWAP] two-qubit gate for a suitable interaction time. We reconstruct by state tomography the coherent dynamics of the two-bit register as a function of the interaction time, observe a violation of the Bell inequality by 22 standard deviations after correcting readout errors, and measure by quantum process tomography a gate fidelity of 90%.